IPAC2015 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
MOBC2	High-Performance Simulations of Coherent Synchrotron Radiation on Multicore GPU and CPU Platforms	GPU, simulation, electron, synchrotron	42
	B. Terzić, A.L. Godunov ODU, Norfolk, Virginia, USA A. Arumugam, D. Ranjan, M. Zubair ODU CS, Norfolk, Virginia, USA
	Coherent synchrotron radiation (CSR) is an effect of self-interaction of an electron bunch as it traverses a curved path. It can cause a significant emittance degradation and microbunching. We present a new high-performance 2D, particle-in-cell code which uses massively parallel multicore GPU/GPU platforms to alleviate computational bottlenecks. The code formulates the CSR problem from first principles by using the retarded scalar and vector potentials to compute the self-interaction fields. The speedup due to the parallel implementation on GPU/CPU platforms exceeds three orders of magnitude, thereby bringing a previously intractable problem within reach. The accuracy of the code is verified against analytic 1D solutions (rigid bunch).
	Slides MOBC2 [4.866 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOBC2
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MOPWA014	New Functionality for Beam Dynamics in Accelerator Toolbox (AT)	lattice, dipole, simulation, emittance	113
	B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.
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MOPWA019	Status of the Robinson Wiggler Project at the Metrology Light Source	wiggler, dipole, dynamic-aperture, damping	132
	T. Goetsch, J. Feikes, M. Ries, G. Wüstefeld HZB, Berlin, Germany
	The beam lifetime in electron storage rings concerns machines running in decay mode as well as machines doing top-up. A standard procedure to increase the lifetime is via bunch lengthening as the lifetime depends on the electron density in the bunch. Bunch lengthening is typically achieved with higher harmonic (Landau) cavities. As noted in , there are several advantages in using a different approach: it is possible to increase the bunch length by installing a Transverse Gradient (Robinson) Wiggler, which allows to transfer damping between the horizontal and the longitudinal plane. While increasing the bunch length, the horizontal emittance is being reduced yielding advantages regarding the source size depending on the magnet optics. At the Metrology Light Source, a primary source standard used by Germanys national metrology institute (Physikalisch-Technische Bundesanstalt), such a scheme is being investigated. The current state of the project including dynamic aperture effects and synchrotron radiation issues of the device is being presented in the following. T. Goetsch et al.,WEPRO028 in Proceedings of IPAC2014, Dresden (Germany), 2014 ** R. Klein et al., Phys. Rev. ST-AB 11, 110701, 2008
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MOPWA021	Transverse Resonance Island Buckets at the MLS and BESSY II	resonance, operation, electron, photon	138
	M. Ries, J. Feikes, T. Goetsch, P. Goslawski, J. Li, M. Ruprecht, A. Schälicke, G. Wüstefeld HZB, Berlin, Germany
	By operating the Metrology Light Source (MLS) near horizontal resonances (fx/frev=1/2, 1/3 or 1/4), two, three or four resonance island buckets may be populated for beam storage. This paper presents experimental results and operational experience such as tuning the machine for high current, controlling inter-bucket diffusion rates, improving overall lifetime and extraction of radiation pulses with sub-revolution repetition rate. First approaches to transfer this mode of operation to the BESSY II storage ring will also be presented.
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MOPWA041	Investigation of Radiation Damage of Insertion Devices at PETRA III due to Particle Losses using Tracking Results with SixTrack	undulator, insertion, insertion-device, synchrotron	203
	G.K. Sahoo, M. Bieler, J. Keil, A. Kling, G. Kube, M. Tischer, R. Wanzenberg DESY, Hamburg, Germany
	PETRA-III is a 3rd generation synchrotron light source dedicated to users at 14 beam lines with 30 instruments since 2009. This operates in 40, 60, 480 or 960 bunches with 100 mA at an electron beam energy of 6 GeV. The horizontal beam emittance is 1nmrad while a coupling of 1% amounts to a vertical emittance of 10 pm-rad. The low emittance is achieved by deploying 80m of damping wigglers in two sections in west and north. Some of these undulators and wiggler devices have accumulated total radiation doses of about 100 kGy. Visible corrosion at the magnet structures of some permanent magnet undulators is seen. High dose rate measured regularly by Thermo Luminescent Dosimeters (TLDs) are monitored, which lead to inspect the magnetic field of all insertion devices in the PETRA tunnel. We are investigating particle losses with tracking simulation using SixTrack to gain a certain understanding of the radiation damage of the insertion devices. The goal is to develop a strategy to safeguard the insertion devices from further radiation damage.
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MOPWA059	Dynamic Aperture Studies for the FCC-ee	lattice, sextupole, collider, synchrotron	258
	L.E. Medina Medrano DCI-UG, León, Mexico R. Martin, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland R. Martin Humboldt University Berlin, Berlin, Germany
	Funding: Work supported by the Beam Project (CONACYT, Mexico). Dynamic aperture (DA) studies have been conducted on the latest Future Circular Collider - ee (FCC-ee) lattices as a function of momentum deviation. Two different schemes for the interaction region are used, which are connected to the main arcs: the crab waist approach, developed by BINP, and an update to the CERN design where the use of crab cavities is envisioned. The results presented show an improvement in the performance of both designs.
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MOPJE001	Effect on Beam Dynamics From Wakefields in Travelling Wave Structure Excited by Bunch Train	wakefield, simulation, electron, dipole	289
	D. Wang, C.-X. Tang TUB, Beijing, People's Republic of China W. Gai, C.-J. Jing, J.G. Power ANL, Argonne, Illinois, USA J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA
	Electron bunch train technology is used to excited coherent high power RF radiation in travelling wave (TW) structures. This article concentrates on the analytical expression of wakefields excited by bunch train in TW structures and the effects of wakefields on beam dynamics. We focus on the first monopole mode and the first dipole mode wakefields. The long range wake function has a linear decrease which agrees well with the ABCi simulations. Taking example of the 11.7 GHz wakefields structure at the Argonne Wakefield Accelerator (AWA) facility, with 1.3 GHz interval drive electron bunch train, we have done the beam dynamics simulation with a point to point (P2P) code. Results shows the effects of wakefields on the energy distribution and the transverse instability for each sub-bunch.
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MOPJE058	FLUKA Modeling of the ESS Accelerator	cryomodule, proton, target, linac	434
	L. Lari, M. Eshraqi, L.S. Esposito, L. Tchelidze ESS, Lund, Sweden F. Cerutti, L.S. Esposito, L. Lari, A. Mereghetti CERN, Geneva, Switzerland
	In order to evaluate the energy deposition and radiation issues concerning the ESS accelerator, a FLUKA model of the machine has been created. The geometry of the superconducting beam line is built according to the machine optics, described in the TraceWin file and the CATIA drawings of the beam elements, using the LineBuilder tool developed at CERN. The objective is to create a flexible FLUKA model that is able to be adapted to the optimization of the optics, design modifications and machine integration constraints. Preliminary results are also presented.
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MOPJE066	Single and Multi-bunch End-to-end Tracking in the LHeC	linac, lattice, synchrotron, synchrotron-radiation	459
	D. Pellegrini, A. Latina, D. Schulte CERN, Geneva, Switzerland S.A. Bogacz JLab, Newport News, Virginia, USA
	The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.
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MOPMA001	Comparison of Measurements and Simulations for Single Bunch Instabilities at Diamond	impedance, wakefield, simulation, synchrotron	521
	M. Atay, R. Bartolini JAI, Oxford, United Kingdom R. Bartolini, R.T. Fielder, I.P.S. Martin DLS, Oxfordshire, United Kingdom
	The single bunch dynamics in the Diamond storage ring has been analysed with a multiparticle tracking code and compared with the results of a wealth of diagnostics, including streak camera, Schottky diodes and FTIR spectra. The interplay of various wakefield sources has been studied and it has been found that the THz spectrum can be reproduced in many cases with simple impedance models, both below and above the bursting threshold.
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MOPMA003	Reconstruction of Electron Bunch Motion During CSR Bursts using Synchronised Diagnostics	electron, detector, synchrotron, storage-ring	529
	I.P.S. Martin, R. Bartolini, C. Bloomer, L.M. Bobb, G. Rehm DLS, Oxfordshire, United Kingdom R. Bartolini, A. Finn JAI, Oxford, United Kingdom
	Above a certain threshold current, electron bunches become unstable and emit bursts of coherent synchrotron radiation (CSR). The character and periodicity of these bursts vary with bunch current, RF voltage and lattice momentum compaction. In this paper we describe recent measurements taken at Diamond of how the electron bunch longitudinal profile and energy vary during a burst, and correlate this with CSR emission at a range of wavelengths.
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MOPMA049	Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility	laser, undulator, experiment, focusing	659
	M.B. Andorf, P. Piot Northern Illinois University, DeKalb, Illinois, USA V.A. Lebedev, P. Piot Fermilab, Batavia, Illinois, USA
	Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.
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MOPMN002	Advances in Parallel Finite Element Code Suite ACE3P	cavity, simulation, SRF, electron	702
	C.-K. Ng, L. Ge, C. Ko, O. Kononenko, Z. Li, L. Xiao SLAC, Menlo Park, California, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515. New capabilities in SLAC's parallel finite element electromagnetics simulation suite ACE3P are reported. These include integrated electromagnetic (Omega3P), thermal and mechanical (TEM3P) modules for multi-physics modeling, an interface to particle-material interaction codes for calculation of radiation effects due to dark current generation (Track3P), and coupled electromagnetic (ACE3P) and beam dynamics (IMPACT) simulation. Results from these applications are presented.
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MOPMN004	CSR Impedance for Non-Ultrarelativistic Beams	impedance, wakefield, space-charge, synchrotron	709
	R. Li JLab, Newport News, Virginia, USA C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
	Funding: This work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. For the analysis of the coherent synchrotron radiation (CSR) induced microbunching gain in the low energy regime, such as when a high-brightness electron beam is transported through a low-energy merger in an energy-recovery linac (ERL) design, it is necessary to extend the CSR impedance expression in the ultrarelativistic limit to the non-ultrarelativistic regime. This paper presents our analysis of CSR impedance for general beam energies.
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MOPMN009	Cross-platform and Cloud-based Access to Multiple Particle Accelerator Codes via Application Containers	Linux, simulation, software, FEL	720
	D.L. Bruhwiler, G. Andonian, M.A. Harrison, S. Seung RadiaBeam, Santa Monica, California, USA D.L. Bruhwiler, R. Nagler, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA P. Moeller Bivio Software Inc., Boulder, USA T.V. Shaftan BNL, Upton, Long Island, New York, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0006284. Particle accelerator and radiation modeling codes focus on specific problems, rely on complicated command-line interfaces, are sometimes limited to a small number of computing platforms, and can be difficult to install. There is also a growing need to use two or more codes together for end-to-end design or for complicated sub-systems. RadTrack is a lightweight cross-platform GUI for such codes, based on the Qt framework and PyQt bindings for Python. RadTrack is designed to support multiple codes, placing no burden on the corresponding development teams. Elegant and the Synchrotron Radiation Workshop (SRW) are supported now in a pre-beta stage, and support for GENESIS 1.3 is under development. These codes are being containerized via the open source Docker platform for use in the cloud. The open source Vagrant and Virtual Box are used for MacOS and Windows. We discuss RadTrack and our vision for cloud computing.
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MOPMN018	A Generic Formulation for Emittance and Lattice Function Evolution for Non-Hamiltonian Systems with Stochastic Effects	emittance, lattice, synchrotron, scattering	740
	J.S. Berg BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. I describe a generic formulation for the evolution of emittances and lattice functions under arbitrary, possibly non-Hamiltonian, linear equations of motion. The average effect of stochastic processes, which would include ionization interactions and synchrotron radiation, is also included. I first compute the evolution of the covariance matrix, then the evolution of emittances and lattice functions from that. I examine the particular case of a cylindrically symmetric system, which is of particular interest for ionization cooling.
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MOPHA004	Oide Limit Mitigation Studies	quadrupole, luminosity, octupole, focusing	781
	O.R. Blanco-García, P. Bambade LAL, Orsay, France R. Tomás CERN, Geneva, Switzerland
	Particle radiation when traversing a focusing quadrupole limits the minimum achievable beam size, known as the Oide limit. This effect may be compensated by a pair of multipoles which reduce the impact of the energy loss in the vertical beam size. Simulations in PLACET using the CLIC 3 TeV QD0 and L⃰ show a reduction of (4.3 ± 0.2)% in the vertical beam size.
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MOPHA023	Observation of Coherent Pulses in the Sub-THz Range at DELTA	electron, detector, laser, synchrotron	823
	C. Mai, F.H. Bahnsen, M. Bolsinger, S. Hilbrich, M. Huck, M. Höner, S. Khan, A. Meyer auf der Heide, R. Molo, H. Rast, G. Shayeganrad, P. Ungelenk DELTA, Dortmund, Germany M. Brosi, B. Kehrer, A.-S. Müller, M.J. Nasse, P. Schönfeldt, P. Schütze, S. Walther KIT, Karlsruhe, Germany H. Huck DESY Zeuthen, Zeuthen, Germany
	Funding: Work supported by the BMBF (05K13PEC). Coherent ultrashort THz pulses induced by a laser-electron interaction are routinely produced and observed at DELTA, a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The turn-by-turn evolution of the radiation spectrum is known to shift to the sub-THz regime after the initial laser-electron interaction. Recently, an ultrafast YBCO-based THz detector has been permanently installed and a Schottky diode has been tested at the THz beamline. Measurements with these detectors showing the temporal evolution of the coherent signals after several revolutions are presented. Furthermore, the concept of a recently designed Fourier-transform spectrometer optimized for the sub-THz region is shown.
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MOPHA029	Operation Experiences with the MICROTCA.4-based LLRF Control System at FLASH	LLRF, operation, electron, laser	844
	M. Omet, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany W. Cichalewski, D.R. Makowski TUL-DMCS, Łódź, Poland K. Czuba, K. Oliwa, I. Rutkowski, R. Rybaniec, D. Sikora, W. Wierba, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland A. Piotrowski FastLogic Sp. z o.o., Łódź, Poland
	The Free-Electron Laser in Hamburg (FLASH) at Deutsches Elektronen-Synchrotron (DESY), Hamburg Germany is a user facility providing ultra-short, femtosecond laser pulses up to the soft X-ray wavelength range. For the precise regulation of the radio frequency (RF) fields within the 60 superconducting cavities, which are organized in 5 RF stations, digital low level RF (LLRF) control systems based on the MTCA.4 standard were implemented in 2013. Until now experiences with failures potentially due to radiation, overheating, and ageing as well as with the general operation of the control systems have been gained. These have a direct impact on the operation and on the performance of FLASH and will allow future improvements. The lessons learned are not only important for FLASH but also in the scope of European X-ray Free-Electron Laser (X-FEL), which will be operated with the same LLRF control system.
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MOPHA037	Visible Light Diagnostics at the ANKA Storage Ring	synchrotron, photon, diagnostics, detector	866
	B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, M. Holz, A.-S. Müller, P. Schönfeldt, P. Schütze KIT, Karlsruhe, Germany
	Synchrotron radiation in the visible light range is a versatile diagnostics tool for accelerator studies. At the ANKA storage ring of the Karlsruhe Institute of Technology (KIT), we have a dedicated visible light diagnostics beamline and two additional beam ports close to the radiation's source point. The visible light diagnostics beamline hosts a time-correlated single-photon-counting unit to measure the bunch filling pattern and a streak camera for longitudinal diagnostics. Recently, the beamline has been extended with a fast-gated intensified camera to study transverse instabilities. The synchrotron light monitor ports were previously used for direct source imaging. Due to the diffraction limit the vertical beam size could not be resolved. One of the two ports has recently been equipped with a double-slit to allow for interferometric measurements of the vertical beam size. In this paper we give an overview of the different setup modifications and present first results.
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MOPHA039	A Fast Gated Intensified Camera Setup for Transversal Beam Diagnostics at the ANKA Storage Ring	storage-ring, experiment, synchrotron, bunching	872
	P. Schütze, A. Borysenko, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, P. Schönfeldt KIT, Karlsruhe, Germany
	ANKA, the synchrotron light source at Karlsruhe Institute of Technology (KIT), can be operated in different modes including the short bunch operation with bunch lengths compressed to a few picoseconds. In this mode, coherent synchrotron radiation (CSR) is emitted leading to beam instabilities. For gaining further insight into those processes, a setup based on a fast gated intensified camera was installed recently at the visible light diagnostics beamline of the ANKA storage ring. The experimental layout consists of an optical setup, which magnifies the image of the beam in the horizontal and demagnifies it in the vertical plane to obtain a projection of the horizontal beam shape, the camera itself and a fast scanning galvanometric mirror that sweeps this image across the sensor. This allows the tracking of the horizontal bunch size and position over many turns. In this paper we present the setup and show first measurement results.
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MOPHA042	Online Studies of THz-radiation in the Bursting Regime at ANKA	synchrotron, optics, synchrotron-radiation, bunching	882
	M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schwarz, P. Schönfeldt, J.L. Steinmann, M. Weber KIT, Eggenstein-Leopoldshafen, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320 The ANKA storage ring of the Karlsruhe Institute of Technology (KIT) operates in the energy range from 0.5 to 2.5 GeV and generates brilliant coherent synchrotron radiation in the THz range with a dedicated bunch length reducing optic. The producing of radiation in the so-called THz-gap is challenging, but this intense THz radiation is very attractive for certain user experiments. The high degree of compression in this so-called low-alpha optics leads to a complex longitudinal dynamics of the electron bunches. The resulting micro-bunching instability leads to time dependent fluctuations and strong bursts in the radiated THz power. The study of these fluctuations in the emitted THz radiation provides insight into the longitudinal beam dynamics. Fast THz detectors combined with KAPTURE, the dedicated KArlsruhe Pulstaking and Ultrafast Readout Electronics system developed at KIT, allow the simultaneous measurement of the radiated THz intensity for each bunch individually in a multi-bunch environment. This contribution gives an overview of the first experience gained using this setup as an online diagnostics tool.
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MOPHA043	Properties of Transition- and Synchrotron Radiation at FLUTE	synchrotron, synchrotron-radiation, electron, detector	885
	M. Schwarz, A.-S. Müller KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	FLUTE (Ferninfrarot Linac Und Test Experiment) is a 41 MeV linear accelerator currently under construction at KIT. It is aimed at accelerator physics and THz radiation research. For this reason the machine will cover a wide range of bunch charges (1 pC up to 3 nC) and lengths (1 fs to 300 fs). One aim of FLUTE is the study of different mechanisms for the generation of intense THz pulses, such as transition- (TR) or synchrotron radiation (SR). In this contribution, we calculate and compare various pulse properties, such as spectra, and electric fields, for both TR and SR.
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MOPHA053	Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity	cavity, linac, detector, coupling	917
	A. Leggieri, F. Di Paolo, D. Passi Università degli Studi di Roma "Tor Vergata", Roma, Italy A. Ciccotelli, S. De Stefano, G. Felici, F. Marangoni S.I.T., Aprilia, Italy
	Beam monitoring system are required by technical standards for the real time measurement of the dose delivered to the target while the beam is crossing them * . Traditional beam current monitoring systems are based on ionization chambers and requires high voltage biases * **. This study investigates on the measurements of the electron beam current emitted by a medical electron linear accelerator using the power exchange of the beam current with a passive resonant cavity *** placed at the output interface of the accelerator. The cavity is magnetically coupled with a coaxial transmission line loaded on a microwave envelope detector and its output signal has been documented while receiving several electron currents. This paper shows the complete equivalency, in terms of global performance, of the current revelation performed by exploiting the cavity-beam interaction principle with the classical technology, based on ionization chambers, however without need of high voltage. The most important point is that the resonant cavity system, by measuring the beam current, gives a direct measurement of a physical observable quantity directly related with the dose deposed by the beam. * EN 60601-2-1, 2009. A.P. Turner, 1979. * V.L. Uvarov, 1997. ** M. Ruf∗, 2014. *** J.B. Rosenzweig, 2003
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MOPTY002	Bunch Length Measurement of Femtosecond Electron Beam by Monitoring Coherent Transition Radiation	electron, detector, gun, linac	940
	I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultrashort electron bunches with durations of femtoseconds and attoseconds are essential for time-resolved measurements, including pulse radiolysis and ultrafast electron microscopy. However, generation of the ultrashort electron bunches is commonly difficult because of bunch length growth due to space charge effect, nonlinear momentum dispersion and so on. Several bunch length measurement methods for the ultrashort electron beams have also been considered so far, which have not been established yet. In this study, the femtosecond electron beams were generated using a laser photocathode radio-frequency gun linac and a magnetic bunch compressor. The bunch length measurement was carried out using a Michelson interferometer based on monitoring coherent transition radiation (CTR), which is characterized by square modulus of the Fourier transform of the longitudinal bunch distribution. Analyzing the experimentally obtained interferograms of CTR, the electron beams with the average duration of 5 fs were generated and measured successfully at the condition of bunch charge of 1 pC. Consideration of the longitudinal bunch shapes was also carried out using the Kramers-Kronig relation.
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MOPTY016	Study of Diamond Detector Application at the Front End of a High Intensity Hadron Accelerator	detector, cavity, hadron, proton	972
	G. Ren, D.H. He, W. Li, Y. Li USTC/NSRL, Hefei, Anhui, People's Republic of China M. Zeng Tsinghua University, Beijing, People's Republic of China
	Diamond detectors function as beam loss or luminosity monitors for high energy accelerators, such as LHC, Babar, etc. Because of regular detectors‘ insufficient protection of the front end, diamond detectors owning significant characteristics, like time resolution in the nanosecond range, radiation hardness and negligible temperature dependence. Thus, diamond detectors have been becoming promising candidates for detecting BLMs of fully super-conducting hadron accelerator, such as C-ADS, FRIB. In this paper, the sensitivity of diamond detectors was simulated by Monte Carlo program FLUKA and GEAN4. Meanwhile, we tested the performance of a new prototype of CVD diamond detector, and compared it with Si-PIN and Bergoz detectors at the storage ring of the HLS II. The results of the diamond detector were consistent with other two detectors well. More evaluation of diamond detectors in low energy radiation field are ongoing.
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MOPTY034	Distributed Beam Loss Monitor Based on the Cherenkov Effect in Optical Fiber	electron, positron, beam-losses, storage-ring	1004
	Yu. Maltseva, F.A. Emanov, A.V. Petrenko, V.G. Prisekin BINP SB RAS, Novosibirsk, Russia F.A. Emanov NSU, Novosibirsk, Russia A.V. Petrenko CERN, Geneva, Switzerland
	A distributed beam loss monitor based on the Cherenkov effect in optical fiber has been implemented for the VEPP5 electron and positron linacs and the 510 MeV damping ring at the Budker INP. The monitor operation is based on detection of the Cherenkov radiation generated in optical fiber by means of relativistic particles created in electromagnetic shower after highly relativistic beam particles (electrons or positrons) hit the vacuum pipe. The main advantage of the distributed monitor compared to local ones is that a long optical fiber section can be used instead of a large number of local beam loss monitors. In our experiments the Cherenkov light was detected by photomultiplier tube (PMT). Timing of PMT signal gives the location of the beam loss. In the experiment with 20 m long optical fiber we achieved 3 m spatial resolution. To improve spatial resolution optimization and selection process of optical fiber and PMT are needed and according to our theoretical estimations 0.5 m spatial resolution can be achieved. We also suggest similar techniques for detection of electron (or positron) losses due to Touschek effect in storage rings.
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MOPTY036	Radiation of a Bunch Moving in the Presence of a Bounded Planar Wire Structure	vacuum, diagnostics, electronics, electromagnetic-fields	1007
	V.V. Vorobev, S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Three-dimensional* and planar periodic structures can be used for non-destructive diagnostics of charged particle bunches. Here we consider the semi-infinite planar structure comprised of thin conducting parallel wires. If the period of the structure is much less than the typical wavelength of the electromagnetic field, then the structure's influence can be described with help of the averaged boundary conditions. We study radiation of a charged particle bunch with small transversal size and arbitrary longitudinal one in two cases: (i) the bunch moves orthogonally to the grid at some distance from the edge and (ii) it moves along the edge of the grid. The problems are solved analytically. In both cases the bunch generates a surface wave which contains the information about the size of the bunch. The shape of the surface waves is similar to the radiation generated in the presence of 3D periodical wire structures, however planar structure is simpler for use in accelerating system. Some typical numerical results for bunches of various shapes are given. * V.V. Vorobev et al., Phys. Rev. Let., 108, 184801 (2012); A.V. Tyukhtin et al., Phys. Rev. ST AB (in press). * M.I. Kontorovich et al., Electrodynamics of Grid Structures (Moscow, 1987).
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MOPTY046	Personnel Safety Systems for the European Spallation Source	PLC, target, controls, neutron	1036
	S.L. Birch, A. Nordt, D. Paulic ESS, Lund, Sweden
	Providing and assuring safe conditions for personnel is a key parameter required to operate the European Spallation Source (ESS). The ESS will be responsible for developing all of the facility personnel safety related systems. All of these systems will be developed by the Integrated Control Systems Division (ICS) and all will be designed, manufactured, commissioned and operated in accordance with the IEC61508 standard, with regard to functional safety for Electrical/Electronic and Programmable Electronic (E/E/PE) safety related systems. This paper describes the ESS Personnel safety system’s scope, strategy, initial design requirements, and methodology but also provides an update of the system design progress so far.
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MOPTY054	Fibre Monitoring System for the Beam Permit Loops at the LHC and Future Evolution of the Beam Interlock System	monitoring, operation, diagnostics, interface	1054
	C. García-Argos, R. Denz, S. Gabourin, C. Martin, B. Puccio, A.P. Siemko CERN, Geneva, Switzerland
	The optical fibres that transmit the beam permit loop signals at the CERN accelerator complex are deployed along radiation areas. This may result in increased attenuation of the fibres, which reduces the power margin of the links. In addition, other events may cause the links to not function properly and result in false dumps, reducing the availability of the accelerator chain and affecting physics data taking. In order to evaluate the state of the fibres, an out-of-band fibre monitoring system is proposed, working in parallel to the actual beam permit loops. The future beam interlock system to be deployed during LHC long shutdown 2 will implement online, real-time monitoring of the fibres, a feature the current system lacks. Commercial off-the-shelf components to implement the optical transceivers are proposed whenever possible instead of ad-hoc designs.
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MOPTY058	Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam	detector, electron, experiment, beam-losses	1069
	O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria
	Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.
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MOPTY070	Online RadFET Reader for Beam Loss Monitoring System	EPICS, controls, network, interface	1097
	C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Wu NSRRC, Hsinchu, Taiwan
	To investigate the beam loss and its distribution during operation of synchrotron light sources at NSSRC, a sixteen-channel readout box is designed and implemented to read the threshold voltage of the RadFETs installed at accelerator tunnel. To simplify the design, the reader plays a role of remote I/O for EPICS IOC. The IOC collects voltage from readers distributed in the accelerator to deduce the integrated dose and dose rate. User interface is shown in the control console for real-time display and the archived data are processed off-line.
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MOPTY072	Beam Loss Study of TLS Using RadFETs	injection, storage-ring, controls, booster	1103
	C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Wu NSRRC, Hsinchu, Taiwan
	To realize the beam loss during the operation of Taiwan light source, P-type radiation-sensing field-effect transistors are setup around the storage ring. A sixteen-channel readout box is used to read the threshold voltage of the radiation-sensing field-effect transistors during irradiation. The beam loss distribution and mechanism at the injection period, decay mode and top up injection for routing operation will be studied in this report.
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MOPTY074	Preliminary Beam Test of Synchrotron Radiation Monitoring System at Taiwan Photon Source	synchrotron, storage-ring, booster, synchrotron-radiation	1109
	C.Y. Liao, Y.-S. Cheng, J. -Y. Chuang, K.T. Hsu, S.Y. Hsu, H.P. Hsueh, K.H. Hu, C.K. Kuan, C.Y. Wu NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a third generation 3 GeV synchrotron light facility. The synchrotron radiation from a dipole can be used to observe the beam parameters. The synchrotron radiation monitor (SRM) systems were designed and implemented for the booster synchrotron and storage ring. The SRM for the booster synchrotron can serve to diagnose the energy ramping process. The beam size decreases when the energy increases was observed. In the storage ring, the streak camera was preferred to observe the beam behaviour of the consecutive bunches. The bunch length and longitudinal instability were observed. The preliminary beam test results are summarized in this report.
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MOPTY080	A Multi-band Single Shot Spectrometer for Observation of mm-Wave Bursts at Diamond Light Source	detector, storage-ring, synchrotron, synchrotron-radiation	1126
	A. Finn, P. Karataev JAI, Egham, Surrey, United Kingdom G. Rehm DLS, Oxfordshire, United Kingdom
	Micro-bunch instabilities (MBI) have been detected at many light sources across the world. The radiation bursts produced as a result of this instability occur in the millimetre wavelength regime. In order to understand more about the mechanism of MBI and improve the accuracy of simulations, more information is needed about the dynamics and spectral content of the radiation. A single shot spectrometer has therefore been developed to investigate this instability at Diamond Light Source. Due to their low noise, ultra-fast response and excellent sensitivity, Schottky detector diodes are employed. Currently, seven Schottky detectors are in place covering a range of 33-750 GHz. Unlike previous measurements at Diamond, each of the Schottky detectors has been characterised thus allowing the results obtained to be more easily compared to simulations. In this paper, we present the calibration of each Schottky detector in the spectrometer, the first results of tests with beam, as well as future plans for the spectrometer.
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MOPWI004	Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation	electron, experiment, laser, optics	1150
	R.B. Fiorito, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom A.G. Shkvarunets UMD, College Park, Maryland, USA
	Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office. Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.
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MOPWI016	Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA	laser, electron, linac, optics	1181
	A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA
	Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy. The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available. A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.
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MOPWI018	New Hadron Monitor By Using A Gas-Filled RF Resonator	electron, plasma, hadron, proton	1189
	K. Yonehara, A.V. Tollestrup, R.M. Zwaska Fermilab, Batavia, Illinois, USA G. Fasce CNI, Roma, Italy G. Flanagan, R.P. Johnson Muons, Inc, Illinois, USA
	It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.
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MOPWI029	Electron Bombardment of ZnTe EO Bunch Charge Detector for Signal Lifetime Studies in Radiation Environment	electron, lattice, detector, laser	1220
	J.E. Williams, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA S.V. Benson, S. Zhang JLab, Newport News, Virginia, USA
	Electro-optic detection of bunch charge distribution utilizing the nonlinear Pockel's and Kerr effect of materials has been implemented at various facilities as a method of passive detection for beam preservation throughout characterization. Most commonly, the inorganic II-VI material ZnTe is employed due to it's strong Pockel's EO effect and relatively high temporal resolution (~90 fs). Despite early exploration of radiation damage on ZnTe in exploration of semi-conductor materials in the 1970's, full characterization of EO response over radiation lifetime has yet to be performed. The following poster presents a method for ZnTe crystal characterization studies throughout radiation exposure at various energies and dosages by analyzing the changes in index of refraction including bulk uniformity, and THz signal response changes.
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MOPWI035	Characterization of Visible Synchrotron Radiation Polarization at SPEAR3	polarization, synchrotron, synchrotron-radiation, diagnostics	1240
	W.J. Corbett, A.M. Kiss SLAC, Menlo Park, California, USA M.J. Boland The University of Melbourne, Melbourne, Victoria, Australia C.L. Li East China University of Science and Technology, Shanghai, People's Republic of China
	Schwinger's equations predict the angular- and spectral distribution of synchrotron radiation across a wide band of the electromagnetic spectrum. Using a visible-light diagnostic beam line, it is possible to characterize the electric field polarization state as a function of vertical observation angle and compare with theory. Complications include accounting for - and π-mode transmission factors at mirror surfaces and precise alignment of the polarizing optics with the principle beam axes. The Stokes parameters are measured and beam polarization ellipse reported.
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MOPWI046	eDT and Model-based Configuration of 12 GeV CEBAF	operation, controls, linac, synchrotron	1259
	D.L. Turner JLab, Newport News, Virginia, USA
	Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. This poster will discuss model-driven setup of CEBAF for the 12GeV era, focusing on the elegant Download Tool (eDT). eDT is a new operator tool that generates magnet design setpoints for various machine energies and pass configurations. eDT was developed in the effort towards a process for reducing machine configuration time and reproducibility by way of an accurate accelerator model.
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TUYB2	Accelerator Physics in ERL Based Polarized Electron Ion Collider	electron, ion, linac, luminosity	1296
	Y. Hao BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.
	Slides TUYB2 [14.101 MB]
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TUAC1	Beam Instrumentation and Diagnostics for High Luminosity LHC	synchrotron, diagnostics, pick-up, collimation	1349
	O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler CERN, Geneva, Switzerland
	The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.
	Slides TUAC1 [4.490 MB]
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TUBC3	Recent Results from FEL seeding at FLASH	FEL, electron, laser, operation	1366
	J. Bödewadt, S. Ackermann, R.W. Aßmann, N. Ekanayake, B. Faatz, G. Feng, I. Hartl, R. Ivanov, T. Laarmann, J.M. Müller, T. Tanikawa DESY, Hamburg, Germany S. Ackermann, Ph. Amstutz, A. Azima, M. Drescher, L.L. Lazzarino, C. Lechner, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Roßbach Uni HH, Hamburg, Germany K.E. Hacker, S. Khan, R. Molo DELTA, Dortmund, Germany
	The free-electron laser facility FLASH at DESY operates since several years in SASE mode, delivering high-intensity FEL pulses in the extreme ultra violet and soft x-ray wavelength range for users. In order to get more control of the characteristics of the FEL pulses external FEL seeding has proven to be a reliable method to do so. At FLASH, an experimental setup to test several different external seeding methods has been installed since 2010. After successful demonstration of direct seeding at 38 nm, the setup is now being operated in HGHG and later EEHG mode. Furthermore, other studies on laser induced effects on the electron beam dynamics have been performed. In this contribution, we give an overview of recent experimental results on FEL seeding at FLASH.
	Slides TUBC3 [6.651 MB]
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TUPWA008	Mixing and Space-Charge Effects In Free-Electron Lasers	laser, electron, FEL, space-charge	1410
	E.A. Peter, A. Endler, F.B. Rizzato IF-UFRGS, Porto Alegre, Brazil A.P.B. Serbeto UFF, Niterói - RJ, Brazil
	Funding: This work was supported by CNPq and FAPERGS, Brazil, and by the Air Force Office of Scientific Research (AFOSR), USA, under the Grant No. FA9550-12-1-0438 Free-electron lasers are devices which efficiently convert the kinetic energy from a relativistic electron beam into electromagnetic radiation, amplifying an initial small sign. The present work revisits the subject of mixing, saturation and space-charge effects in free-electron lasers. Use is made of the compressibility factor, which proves to be a helpful tool in the related systems of charged beams confined by static magnetic fields. The compressibility allows to build a semi-analytical model and to perform analytical estimates of the elapsed time until the onset of mixing, which in turn allows to estimate the saturated amplitude of the radiation field. In addition, the compressibility helps to pinpoint space-charge effects and the corresponding transition from Compton to Raman regimes. The semi-analytical model and the particles simulations are compared, exhibiting a good agreement.* * E. Peter, A. Endler, F. B. Rizzato, and A. Serbeto, Phys. Plasmas 20, 123104 (2013). ** E. Peter, A. Endler, and F. B. Rizzato, Phys. Plasmas 21, 113104 (2014)
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TUPWA017	Collimation scheme for the ESRF Upgrade	lattice, collimation, shielding, beam-losses	1434
	R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White ESRF, Grenoble, France
	The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.
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TUPWA021	A New Method to Generate Ultrashort and Coherent Pulses of Short-Wavelength Synchrotron Radiation	laser, electron, synchrotron, storage-ring	1448
	S. Khan DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF (contract 05K13PE3) A laser-based method to generate ultrashort pulses of synchrotron radiation in electron storage rings is coherent harmonic generation (CHG) using two undulators to produce coherent radiation at harmonics of the initial laser wavelength by microbunching. The bunching factor and thus the pulse intensity, however, decreases exponentially with increasing harmonic order. Echo-enabled harmonic generation (EEHG), proposed in 2009 as FEL seeding scheme, can be used to produce short synchrotron radiation pulses at higher harmonics, but requires three undulators in a straight section. In this paper, a less space-consuming method based on seeding with intensity-modulated laser pulses is introduced, which also has the potential of significant bunching factors at high harmonics. G. Stupakov, PRL 102 (2009), 074801.
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TUPWA022	Characterization and Optimization of Ultrashort and Coherent VUV Pulses at the DELTA Storage Ring	laser, electron, synchrotron, undulator	1452
	S. Khan, F.H. Bahnsen, M. Bolsinger, S. Hilbrich, M. Huck, M. Höner, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, G. Shayeganrad, P. Ungelenk DELTA, Dortmund, Germany H. Huck DESY Zeuthen, Zeuthen, Germany
	Funding: Work supported by BMBF (05K13PE3 and 05K13PEC), DFG (INST 212/236-1 FUGG) and the Land NRW At DELTA, a 1.5-GeV synchrotron light source operated by the TU Dortmund University, a source for coherent and ultrashort vacuum-ultraviolet (VUV) and terahertz (THz) pulses is now in operation. The VUV source is based on a laser-induced energy modulation and coherent harmonic generation (CHG). A subsequently developing dip in the longitudinal electron distribution gives rise to coherent THz radiation. Recent results regarding the optimization of the laser-electron interaction and characterization of the CHG pulses are presented.
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TUPWA043	Non-interferometric Spectral Analysis of Synchrotron Radiation in the THz regime at ANKA	synchrotron, synchrotron-radiation, electron, storage-ring	1509
	J.L. Steinmann, M. Brosi, E. Bründermann, C.M. Caselle, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, M. Schuh, M. Schwarz, P. Schönfeldt, P. Schütze KIT, Karlsruhe, Germany J.L. Hesler Virginia Diodes Inc., Charlottesville, USA
	Interferometry is the quasi-standard for spectral measurements in the THz- and IR-range. The frequency resolution, however, is limited by the travel range of the interferometer mirrors. Therefore, a resolution in the low megahertz range would require interferometer arms of about 100 m. As an alternative, heterodyne measurements provide a resolution in the Hertz range, an improvement of 6 orders of magnitude. Here we present measurements done at ANKA with a VDI WR3.4SAX, a mixer that can be tuned to frequencies from 220 GHz to 330 GHz and we show how the bunch filling pattern influences the amplitude of specific frequencies.
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TUPWA048	Radiative Cooled Target for the ILC Polarized Positron Source	target, positron, vacuum, photon	1526
	A. Ushakov University of Hamburg, Hamburg, Germany F. Dietrich, S. Riemann, T. Rublack DESY Zeuthen, Zeuthen, Germany P. Sievers CERN, Geneva, Switzerland
	Funding: Work supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Optimization", contract number 19XL7IC4 The target for the polarized positron source of the future International Linear Collider (ILC) is designed as wheel of 1 m diameter spinning with 2000 revolutions per minute to distribute the heat load. The target system is placed in vacuum since exit windows would not stand the load. In the current ILC design, the positron target is assumed to be water-cooled. Here, as an alternative, radiative cooling of the target has been studied. The energy deposition in the target is the input for ANSYS simulations. They include the temperature evolution as well as the corresponding thermo-mechanical stress in the target components. A principal design is suggested for further consideration.
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TUPWA061	Analyses of Light's Orbital Angular Momentum from Helical Undulator Harmonics	undulator, polarization, photon, emittance	1563
	S. Sasaki, A. Miyamoto HSRC, Higashi-Hiroshima, Japan M. Hosaka, N. Yamamoto Nagoya University, Nagoya, Japan M. Katoh, T. Konomi UVSOR, Okazaki, Japan
	Funding: Partially supported by the Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, and supported by the Joint Studies Program of the Institute for Molecular Science. The phenomenon of higher harmonic radiation from a helical undulator carrying orbital angular momentum (OAM)* attracts a great deal of attention because this novel property may be used as a new probe for synchrotron radiation science that would be performed in a diffraction limited light source facility such as the APS-II. Although a diffraction limited x-ray source does not yet exist, the 750 MeV UVSOR-III is already a diffraction limited light source in the UV region. In this ring, a tandem-aligned double-APPLE undulator system similar to that in BESSY-II* is installed for FEL and coherent light source experiments. Using this set-up, we observed spiral interference patterns between two different harmonic radiations with a scanning fiber multi-channel spectrometer and a CCD camera placed at the end of BL1U Beamline. By these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical prediction for every mode in the right or left circular polarization. The rotation of an interference pattern by rotating a polarizer was also observed. * S. Sasaki and I. McNulty, Phys. Rev. Lett. 100, 124801, 2008. M. VanVeenendaal and I. McNulty, Phys. Rev. Lett. 98, 157401 (2007). * J. Bahrdt, et al., Phys. Rev. Lett. 111, 034801, 2013.
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TUPWA070	CST Simulations of THz Cherenkov Smith-purcell Radiation from Corrugated Capillary	simulation, electron, polarization, laser	1594
	K. Lekomtsev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan P. Karataev JAI, Egham, Surrey, United Kingdom A. Ponomarenko, A.A. Tishchenko MEPhI, Moscow, Russia
	Recent advances in generation of femtosecond pre-bunched beams have a potential to generate coherent THz radiation occurring via combination of Smith-Purcell radiation (SPR) and Cherenkov radiation (ChR) generated in a corrugated capillary. This mechanism was studied theoretically . LUCX accelerator at High Energy Accelerator Research Organisation (KEK) has been upgraded by introducing fs Ti:Sa laser system and it is currently generating short tens of fs electron bunches . In this report we present EM simulations of Ch.SPR generated in a corrugated channel in infinite dielectric and in a dielectric corrugated capillary. CST PIC solver is used as a simulation tool. It was earlier used for simulation of Transition radiation *. Intensity dependencies of ChR and SPR peaks as functions of the capillary radius and the corrugation depth are compared with the theoretical investigation . Output of THz radiation from the dielectric capillary with a radiation reflector is simulated. * A.A. Ponomarenko et. al, NIMB 309 (2013) 223-226. M. Fukuda et. al, NIMA 637 (2011) S67. * K.V. Lekomtsev et. al, J. Phys.: Conf. Ser. 517, (2014) 012016.
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TUPWA072	Coherent Thomson Scattering Radiation Generated by using PEHG	electron, laser, scattering, undulator	1601
	S. Chen, K. Ohmi, D. Zhou KEK, Ibaraki, Japan S. Huang PKU, Beijing, People's Republic of China
	In this paper, we present the coherent Thomson scattering of a long wavelength laser with ultrashort electron slices. The ultrashort electron slices are generated by the longitudinal bunch density modulation method of PEHG. Coherent radiation with ultrashort pulse length is generated in EUV regime by this method.
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TUPJE001	Design of Wavelength Tunable Coherent X-Ray Source	electron, target, optics, emittance	1604
	J. Hyun Sokendai, Ibaraki, Japan K. Endo TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan K. Hayakawa, Y. Hayakawa, T. Sakai, T. Tanaka LEBRA, Funabashi, Japan I. Sato Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan M. Satoh, M. Yoshida KEK, Ibaraki, Japan
	KEK, Nihon University and TOYAMA CO., Ltd. have been developing the compact shieldless coherent X-ray source that can change the X-ray energy (3-25keV). This X-ray is the Parametric X-ray radiation (PXR) generated by relativistic charged particles passed through a single crystal. It has features that are monochromaticity, coherence and diffraction large angle for the incident beam. These indicate to the possibility for the application to the medical treatment and diagnosis. Furthermore, we try to reduce the radiation which is mainly generated when the high energy beam is damped. This system consists of an accelerating, a decelerating structure and four bending magnets (theta: 90 degree). These structures are operated under low temperature to get the high Q-value for long beam pulse. PXR is generated by colliding with a single crystal after electron beam is accelerated up to 75 MeV. The bunch passed through the crystal is transported into a decelerator structure and then is decelerated to 3 MeV there. Q-magnets are arranged that dispersion function is zero except arc sections. We calculated the beam transport, PXR intensity and emittance blow up. We'll report these details.
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TUPJE004	Narrow Band Coherent Edge Radiation at UVSOR-III	electron, experiment, laser, storage-ring	1613
	M. Hosaka, O. Oodake, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan S. Bielawski, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France M. Katoh, T. Konomi, J. Yamazaki UVSOR, Okazaki, Japan H. Zen Kyoto University, Kyoto, Japan
	Edge radiation can be an interesting new light source because of its property that the radiation is well collimated and is radially polarized. We are developing coherent light sources in the THz region at UVSOR-III storage ring. We have already succeeded in producing a narrow band coherent THz radiation by manipulating the interaction of a relativistic electron bunch with an amplitude modulated laser with. Recently a simplified tentative beamline for detection of the edge radiation is installed at downstream of a short straight section of UVSOR-III. Coherent radiation from electron bunches after the interaction with the amplitude modulated laser is observed. Detailed measurements of polarizations and special distribution of the radiation are underway. The latest status of the study will be reported.
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TUPJE007	Measurement of Temporal Electric Field of Electron Bunch using Photoconductive Antenna	electron, laser, linac, polarization	1623
	K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	A temporal electric field profile, which is a radially polarized terahertz (THz) pulse from an electron bunch, was measured by a large-aperture photoconductive antenna (PCA) with micro-structured concentric electrodes* for the detection of THz pulses. Photo-induced charge carriers were generated by irradiation of femtosecond laser pulses on semiconductor plane of the electrodes on the PCA. Time-domain measurement of coherent transition radiation (CTR) was conducted by the measurement of electric-field-induced current output from the PCA with sweeping the timing of the laser irradiation. The measurements on femtosecond electron bunches of 32 MeV and >80 pC will be reported. * K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).
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TUPJE010	Study of Cs-Te Photocathode for RF Electron Gun	electron, gun, vacuum, scattering	1632
	S. Matsuzaki, M. Nishida, K. Sakaue, M. Washio Waseda University, Tokyo, Japan H. Iijima Tokyo University of Science, Tokyo, Japan
	At Waseda University, we have been studying high quality electron beam with an rf electron gun. In recent accelerator study and application researches, high quality electron beam are strongly required. Photocathode is a key component to generate higher quality electron beam. Cs-Te photocathode shows high quantum efficiency (Q.E.) (~10%) and has long life time (~several months). From 2013, we built a photocathode evaporation chamber and started photocathode study. In this study, our purpose is to clarify their property and to establish an ideal evaporation recipe. We succeeded in producing high quality Cs-Te photocathode, and electron beam generated by our Cs-Te photocathode shows high charge (4.6nC/bunch) and high Q.E. (1.74%) in our rf electron gun. Furthermore, we found a Q.E. recovery after Cs deposition process and it causes higher Q.E. than usual due to, we believe, Cs deposition quantity or Cs deposition speed. Thus we are now surveying the optimum Cs evaporation parameters. In this conference, we will report a detail of our photocathode development system, the latest progress of optimization study of Cs-Te photocathode and future plans. Work supported by Cooperative and Supporting Program for Researches and Educations in Universities and NEDO(New Energy and Industrial Technology Development Organization.
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TUPJE016	COHERENT SYNCHROTRON RADIATION FIELD AND THE ENERGY LOSS IN A WAVY BEAM	electron, wakefield, synchrotron, synchrotron-radiation	1650
	D.R. Xu, H. Xu USTC/NSRL, Hefei, Anhui, People's Republic of China
	The synchrotron radiation will be coherent when the wavelength of the radiation can be compared with the bunch length. There are two approaches to produce Coherent Synchrotron Radiation (CSR) on a storage ring. One is to compress the bunch length, the other one is to produce a wavy beam which has high spatial repetition along the longitudinal direction. The latter one can expand the radiation frequency range of a light source. However, CSR can bring nonlinear effect which brings in extra instability. The Lienard-Wiechert potentials in three-dimensional space may have very complicated forms. The most common way to investigate CSR is numerical method. This paper try to use a simple model to obtain energy loss of the electrons in theory.
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TUPJE017	The Generation of Highly Intense THz Radiation based on Smith-Purcell Radiation	electron, factory, gun, cathode	1654
	Y.F. Xu, Z.G. He, Q.K. Jia, W.W. Li USTC/NSRL, Hefei, Anhui, People's Republic of China
	A photocathode RF gun can generate trains of THz subpicosecond electron bunches by illuminating the cathode with trains of laser pulses. Let this electron bunches passes close to the surface of a lamellar grating, THz radiation will be emitted, which is the so-called Smith-Purcell Radiation (SPR). If the lamellar grating has a narrow groove, this radiation will be narrow-band. By choosing suitable parameter, the SPR frequency can be resonant with the electron bunches frequency, and then generate high intense, narrow band THz radiation.
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TUPJE018	On-axis Injection Scheme for Ultimate Storage Ring with Double RF Systems	injection, synchrotron, emittance, storage-ring	1657
	B.C. Jiang, S.Q. Tian, M.Z. Zhang, Q.L. Zhang, Z.T. Zhentang SINAP, Shanghai, People's Republic of China
	An on-axis injection scheme using double RF systems for an ultimate storage ring which holds very small dynamic aperture is proposed. By altering RF voltages, empty RF buckets can be created which will be used for on-axis injection. After bunches are injected, a reverse voltage altering process is performed and the injected bunches can be longitudinally dumped to the main buckets.
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TUPJE019	Operating Cascaded High-gain Harmonic Generation with Double-pulse Electron Beams	electron, laser, FEL, simulation	1661
	Z. Wang, C. Feng, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China L. Yu BNL, Upton, Long Island, New York, USA
	Cascaded high gain harmonic generation (HGHG) is the primary candidate for the generation of high power, full temporal coherent radiation at the wavelength of nanometer. However, the experimental results at the existing facility show large fluctuation of the output energy pulse at the second stage of cascading. In this paper, we study the scheme of double-pulse electron beams, which is helpful to increase the stability of pulse energy against the timing jitter. The method to generate double-pulse electron beams is shown in the paper and comparison between double-pulse scheme and standard cascaded HGHG is present base on three-dimensional start-to-end simulation to give a straightforward image on the obviously improvement of the FEL stability.
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TUPJE033	A Research on the Reverse Tapering Method to Gain High Power Polarized Photon Beam with Fixed Wavelength	undulator, resonance, electron, simulation	1678
	C.H. Shim, I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Han, Y.W. Parc PAL, Pohang, Kyungbuk, Republic of Korea
	Polarization of soft X-ray photon can be controlled with combination between planar undulators and helical ones. We need to give a reverse tapering to the planar undulators to make microbunching in the electron beam while the linearly polarized radiation power is depressed. In this case, however, resonance wavelengths in each planar undulator are different each other. Therefore, proper initial undulator parameter and tapering strength parameter have to be chosen to obtain high power polarized photon beam with fixed wavelength. In this research, method for deciding suitable reverse tapering is presented using simulation results of PAL-XFEL soft X-ray case with 10 GeV electron beam energy.
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TUPJE037	Magnetic Measurements of the NSLS-II Insertion Devices	insertion, electron, insertion-device, undulator	1693
	M. Musardo, D.A. Harder, C.A. Kitegi, T. Tanabe BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. This paper presents the results and the recent progress in the magnetic measurements of the insertion devices (IDs) for the National Synchrotron Light Source-II (NSLS-II) at Brookhaven National Laboratory (BNL). A detailed analysis of the magnetic measurements is carried out for various IDs with particular attention at the influence of the magnetic field errors on the devices spectral performance. Several specific details of the measurements and the recent results from IDs commissioning are presented.
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TUPJE047	Design Studies for an Upgrade of the SLS Storage Ring	emittance, lattice, storage-ring, operation	1724
	A. Streun, M. Aiba, M. Böge, M.P. Ehrlichman, A. Saá Hernández PSI, Villigen PSI, Switzerland
	An upgrade of the Swiss Light Source (SLS) would replace the existing storage ring by a low aperture multibend achromat lattice providing an emittance of about 100–200 pm at 2.4 GeV, while maintaining the hall, the beam lines and the injector. Since emittance scales inversely cubically with the number of lattice cells, an SLS upgrade is challenged by the comparatively small ring circumference of only 288 m. A new concept for a compact low emittance lattice is based on longitudinal gradient bending magnets for emittance minimization and on anti-bends (i.e bends of opposite field polarity) to disentangle dispersion and horizontal beta function in order to provide the optimum matching to the longitudinal gradient bends while minimizing the contribution to chromaticity.
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TUPJE050	Design of a Resonant Transition Radiation Source in the soft X-ray Range	photon, electron, resonance, vacuum	1735
	P. Wang, K.C. Leou NTHU, Hsinchu, Taiwan N.Y. Huang, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan
	Resonant transition radiation (RTR) can be generated from multi-layer structures when they are driven by relativistic electron beams. In consideration of using the NSRRC 90 MeV photoinjector as driver, we examined the feasibility of generating narrow-band soft x-rays from various multi-layer structures. Based on analytical theory, the expected angular-spectral distribution and photon yield of these radiators are calculated and compared.
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TUPJE060	Development of Advanced Fourth Generation Light Sources for the Accelerator Science Laboratory	electron, simulation, cavity, laser	1765
	T. Chanwattana, R. Bartolini, A. Seryi JAI, Oxford, United Kingdom R. Bartolini DLS, Oxfordshire, United Kingdom E. Tsesmelis CERN, Geneva, Switzerland
	The John Adams Institute for Accelerator Science (JAI) has proposed the realisation of the Accelerator Science Laboratory (ASL) at the University of Oxford as a facility for the development of advanced compact light sources enabling accelerator science research and applications. The installation of a compact light source in the ASL is planned with two options for the accelerating technologies. Firstly, a conventional RF based accelerator is considered to be a driver for a short pulse THz coherent synchrotron radiation (CSR). The other option focusses on the radiation produced by a Laser Plasma Accelerator (LPA) advanced accelerator technique that will provide the possibility to shorten the length of the beamline. This paper presents results of the studies on beam dynamics for both options of compact light sources in the ASL.
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TUPJE065	Multi-Bunch Stability Analysis of the Advanced Photon Source Upgrade Including the Higher-Harmonic Cavity	HOM, damping, impedance, simulation	1784
	L. Emery, T.G. Berenc, M. Borland, R.R. Lindberg ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 Multi-bunch stability simulations were done for the very-low-emittance hybrid seven-bend-achromat (H7BA) lattice proposed for the Advanced Photon Source (APS) upgrade. The simulations, performed using tracking code elegant, were meant to determine whether the long-term wakefields of the higher-order modes (HOMs) of the main 352-MHz cavities will produce an instability. The multi-particle simulations include the important effects of the Higher-Harmonic Cavity (HHC) and the longitudinal impedance of the new vacuum chamber. These realistic simulations show that the HHC provides additional damping in the form of the Landau damping. Still, the HOMs may likely produce a multi-bunch instability which can be cured with more effective HOM damping or a longitudinal feedback system.
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TUPJE073	Results of the Magnetic Tuning of 2.8 m Long Vertically Polarizing Undulator with the Dynamic Compensation of Magnetic Forces	undulator, FEL, electron, free-electron-laser	1809
	I. Vasserman ANL, Argonne, Ilinois, USA
	A novel undulator prototype with a horizontal magnetic field and dynamic compensation of magnetic forces has been recently developed at the APS as a part of the LCLS-II R&D program. This undulator should meet stringent requirements for any LCLS-II insertion device. These requirements include limits on the field integrals and phase errors for all operational gaps, and the reproducibility and accuracy of the gap settings. Extensive mechanical testing has resulted in a performance that meets the requirements on the undulator gap setting. The magnetic tuning has been accomplished by applying a set of magnetic shims. As a result, the satisfactory performance of the undulator prototype has been demonstrated. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory. Argonne, Contract No. DE-AC02-06CH11357.
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TUPJE081	Model of Dark Current in SRF Linac	cavity, linac, electron, quadrupole	1834
	A.I. Sukhanov, A. Saini, N. Solyak, I.S. Tropin Fermilab, Batavia, Illinois, USA
	Currently, few linacs based on 9-cell TESLA-type SRF cavities are being designed or bult, including XEFL, LCLS-II and ILC. Dark current electron generated by field emission in SRF cavities can be captured and accelerated in the linac up to hundreds MeV before they removed by focusing magnets. Lost dark current electrons interact with the materials surrounding SRF cavities and magnets, produce electromagnetic showers and contribute to the radiation in the linac tunnel. In this paper we present a model of dark current in a linac based on TESLA cavities. We show preliminary results of the simulation applied to ILC main linac.
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TUPMA001	Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source	optics, injection, photon, lattice	1840
	C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallén, W. Wan LBNL, Berkeley, California, USA
	Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231. Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics.
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TUPMA007	Numerical Investigation of a Cascaded Longitudinal Space-Charge Amplifier at the Fermilab's Advanced Superconducting Test Accelerator	space-charge, bunching, simulation, impedance	1850
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	In a cascaded longitudinal space-charge amplifier (LSCA), initial density noise in a relativistic e-beam is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. This type of amplification process was shown to potentially result in large final density modulations * compatible with the production of broadband electromagnetic radiation. The technique was recently demonstrated in the optical domain *. In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA). We especially explore the properties of the produced broadband radiation. Our studies have been conducted with an effective three-dimensional space-charge algorithm. Dohlus, M. et al. Proc. SPIE 8779. doi:10.1117/12.2017369 ** Marinelli, A. et al. Phys. Rev. Lett. 110, 264802 (2013)
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TUPMA008	Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance	impedance, space-charge, simulation, detector	1853
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such "microbunching instabilities" were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body "Barnes-Hut" algorithm * to simulate the 3D space charge force in the beam combined with Elegant ** and explore the limitation of the 1D model often used. * Barnes, J. & Hut, P., Nature 324, 446-449, 1986. ** Borland, M., Advanced Photon Source LS-287, 2000.
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TUPMA021	Optimization of an Improved SASE (iSASE) FEL	FEL, lattice, undulator, simulation	1881
	L. Gupta Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA K. Fang, J. Wu SLAC, Menlo Park, California, USA
	Funding: Supported by US DOE FWP-2013-SLAC-100164 and DOE SULI. In order to improve free electron laser technology for the future LCLSII at SLAC, a new strategy for creating radiation with increased temporal coherence is under development. The improved Self-Amplified Spontaneous Emission (iSASE) FEL utilizes phase shifters which allow for the spontaneously emitted radiation to interact with and stimulate more electrons to radiate coherently. Five phase shifters were simulated, with 34 normal-conducting undulators and focusing-defocusing quadrupoles as an LCLSII FEL lattice using the FEL software Genesis 1.3. Two general schemes, one providing a total phase shift of arbitrary distribution, the other providing a sequential or distributed phase shift, were simulated and optimized using a simulated annealing algorithm. The results suggest that the phase shifters must provide a total shift comparable to the bunch length, and the shifts must be distributed with one large shift, followed by smaller shifts. * J. Wu, A. Marinelli, C. Pellegrini, Proc. FEL2012, pp. 237, Japan (2012). ** J. Wu, et al., Proc. IPAC2013, pp. 2068, China (2013).
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TUPMA023	Two-Dimensional Calculation of Channeling Radiation Spectrum for High-Brightness Hard X-Ray Production	electron, lattice, ion, brightness	1888
	W.D. Rush, J. Shi KU, Lawrence, Kansas, USA
	The channeling radiation spectrum is calculated without using the one-dimensional approximation in the planar channeling radiation model or the single-string approximation in the axial channeling radiation model. The obtained spectrum of the two-dimensional channeling radiaiton is significantly different from those previously calculated with the approximations. The calculation presented here is of the channeling radiation experiments conducted at Fermilab Advanced Superconducting Test Accelerator (ASTA) photoinjector with electron beam energies of 20-50 MeV and a diamond target. The computational method developed in this work can be applied to general cases of different crystals and beams with different energy and emittances.
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TUPMA030	Narrowband Continuously Tunable Radiation in the 5 to 10 Terahertz Range by Inverse Compton Scattering	electron, laser, photon, scattering	1901
	Z. Wu, K. Fang, M.-H. Wang, J. Wu SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy under Grants DE-AC02-76SF00515, DE-FG02-13ER41970 and by DARPA Grant N66001-11-1-4199. 5 to 10 THz has recently become the frontier of THz radiation sources development, pushed by the growing interests of spectroscopy and pump-probe material study in this frequency range. This spectrum “Gap” lies in between the several THz range covered by Electro-Optical crystal based THz generation, and the tens of THz range covered by the difference frequency generation method. The state-of-the-art EO crystal THz source using tilted pulse front technique has been able to reach ~ 100 MV/m peak field strength, large enough to be used in an inverse Compton scattering process to push these low energy photons to shorter wavelengths of the desired 5-10 THz range. The required electron beam energy is within 1~2 MeV, therefore a compact footprint of the whole system. The process would occur coherently granted the electron beam is bunched to a fraction of the radiation wavelengths (several microns). A system operating at KHz or even MHz repetition rate is possible given the low electron energy and thus low RF acceleration gradient required. This work will explore the scheme with design parameters and simulation results.
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TUPMA036	First e-/Photon Commissioning Results for the GlueX Experiment/Hall D at CEBAF	photon, detector, acceleration, target	1916
	M.D. McCaughan, J. F. Benesch, Y. Roblin, T. Satogata JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Experimental Hall D, with flagship experiment GlueX, was constructed as part of the 12 GeV CEBAF upgrade. A new magnetically extracted electron beam line was installed to support this hall. Bremsstrahlung photons from retractable radiators, are delivered to the experiment through a series of collimators following a long drift to allow for beam convergence. Coherent Bremsstrahlung generated by interaction with a diamond radiator will achieve a nominal 40% linear polarization and photon energies between 8.5 and 9 GeV from 12.1 GeV electrons, which are then tagged or diverted to a medium power 60kW electron dump. The expected photon flux is 107-10⁸ Hz. This paper discusses the experimental line design, commissioning experience gained since first beam in spring 2014, and the present results of beam commissioning by the experiment.
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TUPMA041	On the Characterization of a CCR Source	brightness, FEL, impedance, emittance	1926
	A.V. Smirnov RadiaBeam, Santa Monica, California, USA
	Funding: US Department of Energy, contract # DE- SC-FOA-0000760 Peak and spectral brightness of a resonant long-range wakefield extractor are evaluated. It is shown that the brightness is dominated by beam density within the slow wave structure and antenna gain of the outcoupling. Far field radiation patterns and brightness of circular and high-aspect-ratio planar radiators are compared. A possibility to approach the diffraction limited brightness is demonstrated. Role of group velocity in designing of the Cherenkov source is emphasized. The approach can be applied for design and characterization of various structure-dominated sources (e.g., wakefield extractors with gratings or dielectrics, or FEL-Cherenkov combined sources) radiating into a free space using an antenna (from microwave to far infra-red regions). The high group velocity structures can be also effective as energy dechirpers and for diagnostics of microbunched relativistic electron beams.
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TUPMA042	THz Radiation Generation in a Multimode Wakefield Structure	wakefield, experiment, electron, linac	1929
	S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin BNL, Upton, Long Island, New York, USA W. Gai, D. Wang, A. Zholents ANL, Argonne, Illinois, USA
	Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571 A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.
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TUPMA055	Analysis of Possible Beam Losses in the NSLS II Storage Ring	dipole, storage-ring, shielding, electron	1956
	S. Seletskiy, R.P. Fliller, W. Guo, S.L. Kramer, Y. Li, B. Podobedov, T.V. Shaftan, W.H. Wahl, F.J. Willeke BNL, Upton, Long Island, New York, USA
	The NSLS-II accelerators are installed within radiation shielding walls that are designed to attenuate the radiation generated from an assumed beam loss power to a level of <0.5mrem/h at the outer surface of the bulk shield walls. Any operational losses greater than specified level are expected to be addressed by installing supplemental shielding near the loss point in order to attenuate the radiation outside the shield wall to the design level. In this paper we report the analysis of the electron beam mis-steering in the NSLS-II storage ring for the determination of supplementary shielding.
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TUPMA056	Analysis of Possible Beam Losses in the NSLS II BSR Transfer Line	booster, storage-ring, shielding, extraction	1959
	S. Seletskiy, R.P. Fliller, W. Guo, S.L. Kramer, Y. Li, B. Podobedov, T.V. Shaftan, W.H. Wahl, F.J. Willeke BNL, Upton, Long Island, New York, USA
	The NSLS-II accelerators are installed within 0.8 – 1 m thick radiation shielding walls. The safety considerations require attenuating the radiation generated from possible electron beam losses to a level of <0.5mrem/h at the outer surface of the bulk shield walls. Any operational losses greater than specified level shall be addressed by installing supplemental shielding near the loss point. In this paper we discuss simulation studies that identified potential beam loss locations. Results of these studies were used for identification of imposed radiation risks and for specification of the supplemental shielding design necessary to mitigate those risks.
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TUPMA057	Commissioning of Active Interlock System for NSLS II Storage Ring	storage-ring, synchrotron, synchrotron-radiation, photon	1962
	S. Seletskiy, C. Amundsen, J. Choi, J.H. De Long, K.M. Ha, C. Hetzel, H.-C. Hseuh, Y. Hu, P. Ilinski, S.L. Kramer, Y. Li, M.A. Maggipinto, J. Mead, D. Padrazo, T.V. Shaftan, G. Shen, O. Singh, R.M. Smith, W.H. Wahl, G.M. Wang, F.J. Willeke, L. Yang BNL, Upton, Long Island, New York, USA
	The NSLS-II storage ring is protected from possible damage from insertion devices (IDs) synchrotron radiation by a dedicated active interlock system (AIS). It monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope. In this paper we describe functional details of the AIS and discuss our experience with commissioning of the AIS for the first six IDs installed in the storage ring.
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TUPHA003	Sputter Growth of Alkali Antimonide Photocathodes: An in Operando Materials Analysis	cathode, target, emittance, gun	1965
	J. Smedley, K. Attenkofer, M. Gaowei, J. Sinsheimer, J. Walsh BNL, Upton, Long Island, New York, USA H. Bhandari Radiation Monitoring Devices, Watertown, USA Z. Ding, E.M. Muller SBU, Stony Brook, New York, USA H.J. Frisch Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA H.A. Padmore, S.G. Schubert, J.J. Wong LBNL, Berkeley, California, USA
	Funding: Work supported by U.S. DoE, under KC0407-ALSJNT-I0013 and SBIR grant # DE-SC0009540. NSLS was supported by DOE DE-AC02-98CH10886, CHESS is supported by NSF & NIH/NIGMS via NSF DMR-1332208 Alkali antimonide photocathodes are a strong contender for the cathode of choice for next-generation photon sources such as LCLS II or the XFEL. These materials have already found extensive use in photodetectors and image intensifiers. However, only recently have modern synchrotron techniques enabled a systematic study of the formation chemistry of these materials. Such analysis has led to the understanding that these materials are inherently rough when grown through traditional sequential deposition; this roughness has a detrimental impact on the intrinsic emittance of the emitted beam. Sputter deposition may provide a path to achieving a far smoother photocathode, while maintaining adequate quantum efficiency. We report on the creation and vacuum transport of a K2CsSb sputter target, and its use to create an ultra-smooth (sub nm roughness) cathode with a 2% quantum efficiency at 532 nm.
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TUPTY001	Interaction Region for a 100 TeV Proton-Proton Collider	shielding, quadrupole, interaction-region, dipole	1996
	R. Martin, R. Tomás CERN, Geneva, Switzerland B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, FCC-hh, running at center-of-mass energies of up to 100 TeV, pushing the energy frontier of fundamental physics to a new limit. At a circumference of 80-100 km, this machine is planned to use the same tunnel as FCC-ee, a proposed 90-350 GeV high luminosity electron-positron collider. This paper presents the design progress and technical challenges for the interaction region of FCC-hh.
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Paper

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MOBC2

High-Performance Simulations of Coherent Synchrotron Radiation on Multicore GPU and CPU Platforms

GPU, simulation, electron, synchrotron

42

B. Terzić, A.L. Godunov
ODU, Norfolk, Virginia, USA
A. Arumugam, D. Ranjan, M. Zubair
ODU CS, Norfolk, Virginia, USA

Coherent synchrotron radiation (CSR) is an effect of self-interaction of an electron bunch as it traverses a curved path. It can cause a significant emittance degradation and microbunching. We present a new high-performance 2D, particle-in-cell code which uses massively parallel multicore GPU/GPU platforms to alleviate computational bottlenecks. The code formulates the CSR problem from first principles by using the retarded scalar and vector potentials to compute the self-interaction fields. The speedup due to the parallel implementation on GPU/CPU platforms exceeds three orders of magnitude, thereby bringing a previously intractable problem within reach. The accuracy of the code is verified against analytic 1D solutions (rigid bunch).

Slides MOBC2 [4.866 MB]

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MOPWA014

New Functionality for Beam Dynamics in Accelerator Toolbox (AT)

lattice, dipole, simulation, emittance

113

B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.

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MOPWA019

Status of the Robinson Wiggler Project at the Metrology Light Source

wiggler, dipole, dynamic-aperture, damping

132

T. Goetsch, J. Feikes, M. Ries, G. Wüstefeld
HZB, Berlin, Germany

The beam lifetime in electron storage rings concerns machines running in decay mode as well as machines doing top-up. A standard procedure to increase the lifetime is via bunch lengthening as the lifetime depends on the electron density in the bunch. Bunch lengthening is typically achieved with higher harmonic (Landau) cavities. As noted in *, there are several advantages in using a different approach: it is possible to increase the bunch length by installing a Transverse Gradient (Robinson) Wiggler, which allows to transfer damping between the horizontal and the longitudinal plane. While increasing the bunch length, the horizontal emittance is being reduced yielding advantages regarding the source size depending on the magnet optics. At the Metrology Light Source, a primary source standard used by Germanys national metrology institute (Physikalisch-Technische Bundesanstalt)**, such a scheme is being investigated. The current state of the project including dynamic aperture effects and synchrotron radiation issues of the device is being presented in the following.
* T. Goetsch et al.,WEPRO028 in Proceedings of IPAC2014, Dresden (Germany), 2014
** R. Klein et al., Phys. Rev. ST-AB 11, 110701, 2008

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MOPWA021

Transverse Resonance Island Buckets at the MLS and BESSY II

resonance, operation, electron, photon

138

M. Ries, J. Feikes, T. Goetsch, P. Goslawski, J. Li, M. Ruprecht, A. Schälicke, G. Wüstefeld
HZB, Berlin, Germany

By operating the Metrology Light Source (MLS) near horizontal resonances (fx/frev=1/2, 1/3 or 1/4), two, three or four resonance island buckets may be populated for beam storage. This paper presents experimental results and operational experience such as tuning the machine for high current, controlling inter-bucket diffusion rates, improving overall lifetime and extraction of radiation pulses with sub-revolution repetition rate. First approaches to transfer this mode of operation to the BESSY II storage ring will also be presented.

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MOPWA041

Investigation of Radiation Damage of Insertion Devices at PETRA III due to Particle Losses using Tracking Results with SixTrack

undulator, insertion, insertion-device, synchrotron

203

G.K. Sahoo, M. Bieler, J. Keil, A. Kling, G. Kube, M. Tischer, R. Wanzenberg
DESY, Hamburg, Germany

PETRA-III is a 3rd generation synchrotron light source dedicated to users at 14 beam lines with 30 instruments since 2009. This operates in 40, 60, 480 or 960 bunches with 100 mA at an electron beam energy of 6 GeV. The horizontal beam emittance is 1nmrad while a coupling of 1% amounts to a vertical emittance of 10 pm-rad. The low emittance is achieved by deploying 80m of damping wigglers in two sections in west and north. Some of these undulators and wiggler devices have accumulated total radiation doses of about 100 kGy. Visible corrosion at the magnet structures of some permanent magnet undulators is seen. High dose rate measured regularly by Thermo Luminescent Dosimeters (TLDs) are monitored, which lead to inspect the magnetic field of all insertion devices in the PETRA tunnel. We are investigating particle losses with tracking simulation using SixTrack to gain a certain understanding of the radiation damage of the insertion devices. The goal is to develop a strategy to safeguard the insertion devices from further radiation damage.

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MOPWA059

Dynamic Aperture Studies for the FCC-ee

lattice, sextupole, collider, synchrotron

258

L.E. Medina Medrano
DCI-UG, León, Mexico
R. Martin, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
R. Martin
Humboldt University Berlin, Berlin, Germany

Funding: Work supported by the Beam Project (CONACYT, Mexico).
Dynamic aperture (DA) studies have been conducted on the latest Future Circular Collider - ee (FCC-ee) lattices as a function of momentum deviation. Two different schemes for the interaction region are used, which are connected to the main arcs: the crab waist approach, developed by BINP, and an update to the CERN design where the use of crab cavities is envisioned. The results presented show an improvement in the performance of both designs.

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MOPJE001

Effect on Beam Dynamics From Wakefields in Travelling Wave Structure Excited by Bunch Train

wakefield, simulation, electron, dipole

289

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
W. Gai, C.-J. Jing, J.G. Power
ANL, Argonne, Illinois, USA
J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA

Electron bunch train technology is used to excited coherent high power RF radiation in travelling wave (TW) structures. This article concentrates on the analytical expression of wakefields excited by bunch train in TW structures and the effects of wakefields on beam dynamics. We focus on the first monopole mode and the first dipole mode wakefields. The long range wake function has a linear decrease which agrees well with the ABCi simulations. Taking example of the 11.7 GHz wakefields structure at the Argonne Wakefield Accelerator (AWA) facility, with 1.3 GHz interval drive electron bunch train, we have done the beam dynamics simulation with a point to point (P2P) code. Results shows the effects of wakefields on the energy distribution and the transverse instability for each sub-bunch.

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MOPJE058

FLUKA Modeling of the ESS Accelerator

cryomodule, proton, target, linac

434

L. Lari, M. Eshraqi, L.S. Esposito, L. Tchelidze
ESS, Lund, Sweden
F. Cerutti, L.S. Esposito, L. Lari, A. Mereghetti
CERN, Geneva, Switzerland

In order to evaluate the energy deposition and radiation issues concerning the ESS accelerator, a FLUKA model of the machine has been created. The geometry of the superconducting beam line is built according to the machine optics, described in the TraceWin file and the CATIA drawings of the beam elements, using the LineBuilder tool developed at CERN. The objective is to create a flexible FLUKA model that is able to be adapted to the optimization of the optics, design modifications and machine integration constraints. Preliminary results are also presented.

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MOPJE066

Single and Multi-bunch End-to-end Tracking in the LHeC

linac, lattice, synchrotron, synchrotron-radiation

459

D. Pellegrini, A. Latina, D. Schulte
CERN, Geneva, Switzerland
S.A. Bogacz
JLab, Newport News, Virginia, USA

The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.

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MOPMA001

Comparison of Measurements and Simulations for Single Bunch Instabilities at Diamond

impedance, wakefield, simulation, synchrotron

521

M. Atay, R. Bartolini
JAI, Oxford, United Kingdom
R. Bartolini, R.T. Fielder, I.P.S. Martin
DLS, Oxfordshire, United Kingdom

The single bunch dynamics in the Diamond storage ring has been analysed with a multiparticle tracking code and compared with the results of a wealth of diagnostics, including streak camera, Schottky diodes and FTIR spectra. The interplay of various wakefield sources has been studied and it has been found that the THz spectrum can be reproduced in many cases with simple impedance models, both below and above the bursting threshold.

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MOPMA003

Reconstruction of Electron Bunch Motion During CSR Bursts using Synchronised Diagnostics

electron, detector, synchrotron, storage-ring

529

I.P.S. Martin, R. Bartolini, C. Bloomer, L.M. Bobb, G. Rehm
DLS, Oxfordshire, United Kingdom
R. Bartolini, A. Finn
JAI, Oxford, United Kingdom

Above a certain threshold current, electron bunches become unstable and emit bursts of coherent synchrotron radiation (CSR). The character and periodicity of these bursts vary with bunch current, RF voltage and lattice momentum compaction. In this paper we describe recent measurements taken at Diamond of how the electron bunch longitudinal profile and energy vary during a burst, and correlate this with CSR emission at a range of wavelengths.

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MOPMA049

Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility

laser, undulator, experiment, focusing

659

M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, P. Piot
Fermilab, Batavia, Illinois, USA

Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.

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MOPMN002

Advances in Parallel Finite Element Code Suite ACE3P

cavity, simulation, SRF, electron

702

C.-K. Ng, L. Ge, C. Ko, O. Kononenko, Z. Li, L. Xiao
SLAC, Menlo Park, California, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515.
New capabilities in SLAC's parallel finite element electromagnetics simulation suite ACE3P are reported. These include integrated electromagnetic (Omega3P), thermal and mechanical (TEM3P) modules for multi-physics modeling, an interface to particle-material interaction codes for calculation of radiation effects due to dark current generation (Track3P), and coupled electromagnetic (ACE3P) and beam dynamics (IMPACT) simulation. Results from these applications are presented.

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MOPMN004

CSR Impedance for Non-Ultrarelativistic Beams

impedance, wakefield, space-charge, synchrotron

709

R. Li
JLab, Newport News, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Funding: This work is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
For the analysis of the coherent synchrotron radiation (CSR) induced microbunching gain in the low energy regime, such as when a high-brightness electron beam is transported through a low-energy merger in an energy-recovery linac (ERL) design, it is necessary to extend the CSR impedance expression in the ultrarelativistic limit to the non-ultrarelativistic regime. This paper presents our analysis of CSR impedance for general beam energies.

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MOPMN009

Cross-platform and Cloud-based Access to Multiple Particle Accelerator Codes via Application Containers

Linux, simulation, software, FEL

720

D.L. Bruhwiler, G. Andonian, M.A. Harrison, S. Seung
RadiaBeam, Santa Monica, California, USA
D.L. Bruhwiler, R. Nagler, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
P. Moeller
Bivio Software Inc., Boulder, USA
T.V. Shaftan
BNL, Upton, Long Island, New York, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0006284.
Particle accelerator and radiation modeling codes focus on specific problems, rely on complicated command-line interfaces, are sometimes limited to a small number of computing platforms, and can be difficult to install. There is also a growing need to use two or more codes together for end-to-end design or for complicated sub-systems. RadTrack is a lightweight cross-platform GUI for such codes, based on the Qt framework and PyQt bindings for Python. RadTrack is designed to support multiple codes, placing no burden on the corresponding development teams. Elegant and the Synchrotron Radiation Workshop (SRW) are supported now in a pre-beta stage, and support for GENESIS 1.3 is under development. These codes are being containerized via the open source Docker platform for use in the cloud. The open source Vagrant and Virtual Box are used for MacOS and Windows. We discuss RadTrack and our vision for cloud computing.

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MOPMN018

A Generic Formulation for Emittance and Lattice Function Evolution for Non-Hamiltonian Systems with Stochastic Effects

emittance, lattice, synchrotron, scattering

740

J.S. Berg
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
I describe a generic formulation for the evolution of emittances and lattice functions under arbitrary, possibly non-Hamiltonian, linear equations of motion. The average effect of stochastic processes, which would include ionization interactions and synchrotron radiation, is also included. I first compute the evolution of the covariance matrix, then the evolution of emittances and lattice functions from that. I examine the particular case of a cylindrically symmetric system, which is of particular interest for ionization cooling.

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MOPHA004

Oide Limit Mitigation Studies

quadrupole, luminosity, octupole, focusing

781

O.R. Blanco-García, P. Bambade
LAL, Orsay, France
R. Tomás
CERN, Geneva, Switzerland

Particle radiation when traversing a focusing quadrupole limits the minimum achievable beam size, known as the Oide limit. This effect may be compensated by a pair of multipoles which reduce the impact of the energy loss in the vertical beam size. Simulations in PLACET using the CLIC 3 TeV QD0 and L⃰ show a reduction of (4.3 ± 0.2)% in the vertical beam size.

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MOPHA023

Observation of Coherent Pulses in the Sub-THz Range at DELTA

electron, detector, laser, synchrotron

823

C. Mai, F.H. Bahnsen, M. Bolsinger, S. Hilbrich, M. Huck, M. Höner, S. Khan, A. Meyer auf der Heide, R. Molo, H. Rast, G. Shayeganrad, P. Ungelenk
DELTA, Dortmund, Germany
M. Brosi, B. Kehrer, A.-S. Müller, M.J. Nasse, P. Schönfeldt, P. Schütze, S. Walther
KIT, Karlsruhe, Germany
H. Huck
DESY Zeuthen, Zeuthen, Germany

Funding: Work supported by the BMBF (05K13PEC).
Coherent ultrashort THz pulses induced by a laser-electron interaction are routinely produced and observed at DELTA, a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The turn-by-turn evolution of the radiation spectrum is known to shift to the sub-THz regime after the initial laser-electron interaction. Recently, an ultrafast YBCO-based THz detector has been permanently installed and a Schottky diode has been tested at the THz beamline. Measurements with these detectors showing the temporal evolution of the coherent signals after several revolutions are presented. Furthermore, the concept of a recently designed Fourier-transform spectrometer optimized for the sub-THz region is shown.

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MOPHA029

Operation Experiences with the MICROTCA.4-based LLRF Control System at FLASH

LLRF, operation, electron, laser

844

M. Omet, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
W. Cichalewski, D.R. Makowski
TUL-DMCS, Łódź, Poland
K. Czuba, K. Oliwa, I. Rutkowski, R. Rybaniec, D. Sikora, W. Wierba, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
A. Piotrowski
FastLogic Sp. z o.o., Łódź, Poland

The Free-Electron Laser in Hamburg (FLASH) at Deutsches Elektronen-Synchrotron (DESY), Hamburg Germany is a user facility providing ultra-short, femtosecond laser pulses up to the soft X-ray wavelength range. For the precise regulation of the radio frequency (RF) fields within the 60 superconducting cavities, which are organized in 5 RF stations, digital low level RF (LLRF) control systems based on the MTCA.4 standard were implemented in 2013. Until now experiences with failures potentially due to radiation, overheating, and ageing as well as with the general operation of the control systems have been gained. These have a direct impact on the operation and on the performance of FLASH and will allow future improvements. The lessons learned are not only important for FLASH but also in the scope of European X-ray Free-Electron Laser (X-FEL), which will be operated with the same LLRF control system.

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MOPHA037

Visible Light Diagnostics at the ANKA Storage Ring

synchrotron, photon, diagnostics, detector

866

B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, M. Holz, A.-S. Müller, P. Schönfeldt, P. Schütze
KIT, Karlsruhe, Germany

Synchrotron radiation in the visible light range is a versatile diagnostics tool for accelerator studies. At the ANKA storage ring of the Karlsruhe Institute of Technology (KIT), we have a dedicated visible light diagnostics beamline and two additional beam ports close to the radiation's source point. The visible light diagnostics beamline hosts a time-correlated single-photon-counting unit to measure the bunch filling pattern and a streak camera for longitudinal diagnostics. Recently, the beamline has been extended with a fast-gated intensified camera to study transverse instabilities. The synchrotron light monitor ports were previously used for direct source imaging. Due to the diffraction limit the vertical beam size could not be resolved. One of the two ports has recently been equipped with a double-slit to allow for interferometric measurements of the vertical beam size. In this paper we give an overview of the different setup modifications and present first results.

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MOPHA039

A Fast Gated Intensified Camera Setup for Transversal Beam Diagnostics at the ANKA Storage Ring

storage-ring, experiment, synchrotron, bunching

872

P. Schütze, A. Borysenko, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, P. Schönfeldt
KIT, Karlsruhe, Germany

ANKA, the synchrotron light source at Karlsruhe Institute of Technology (KIT), can be operated in different modes including the short bunch operation with bunch lengths compressed to a few picoseconds. In this mode, coherent synchrotron radiation (CSR) is emitted leading to beam instabilities. For gaining further insight into those processes, a setup based on a fast gated intensified camera was installed recently at the visible light diagnostics beamline of the ANKA storage ring. The experimental layout consists of an optical setup, which magnifies the image of the beam in the horizontal and demagnifies it in the vertical plane to obtain a projection of the horizontal beam shape, the camera itself and a fast scanning galvanometric mirror that sweeps this image across the sensor. This allows the tracking of the horizontal bunch size and position over many turns. In this paper we present the setup and show first measurement results.

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MOPHA042

Online Studies of THz-radiation in the Bursting Regime at ANKA

synchrotron, optics, synchrotron-radiation, bunching

882

M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schwarz, P. Schönfeldt, J.L. Steinmann, M. Weber
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320
The ANKA storage ring of the Karlsruhe Institute of Technology (KIT) operates in the energy range from 0.5 to 2.5 GeV and generates brilliant coherent synchrotron radiation in the THz range with a dedicated bunch length reducing optic. The producing of radiation in the so-called THz-gap is challenging, but this intense THz radiation is very attractive for certain user experiments. The high degree of compression in this so-called low-alpha optics leads to a complex longitudinal dynamics of the electron bunches. The resulting micro-bunching instability leads to time dependent fluctuations and strong bursts in the radiated THz power. The study of these fluctuations in the emitted THz radiation provides insight into the longitudinal beam dynamics. Fast THz detectors combined with KAPTURE, the dedicated KArlsruhe Pulstaking and Ultrafast Readout Electronics system developed at KIT, allow the simultaneous measurement of the radiated THz intensity for each bunch individually in a multi-bunch environment. This contribution gives an overview of the first experience gained using this setup as an online diagnostics tool.

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MOPHA043

Properties of Transition- and Synchrotron Radiation at FLUTE

synchrotron, synchrotron-radiation, electron, detector

885

M. Schwarz, A.-S. Müller
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

FLUTE (Ferninfrarot Linac Und Test Experiment) is a 41 MeV linear accelerator currently under construction at KIT. It is aimed at accelerator physics and THz radiation research. For this reason the machine will cover a wide range of bunch charges (1 pC up to 3 nC) and lengths (1 fs to 300 fs). One aim of FLUTE is the study of different mechanisms for the generation of intense THz pulses, such as transition- (TR) or synchrotron radiation (SR). In this contribution, we calculate and compare various pulse properties, such as spectra, and electric fields, for both TR and SR.

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MOPHA053

Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity

cavity, linac, detector, coupling

917

A. Leggieri, F. Di Paolo, D. Passi
Università degli Studi di Roma "Tor Vergata", Roma, Italy
A. Ciccotelli, S. De Stefano, G. Felici, F. Marangoni
S.I.T., Aprilia, Italy

Beam monitoring system are required by technical standards for the real time measurement of the dose delivered to the target while the beam is crossing them * **. Traditional beam current monitoring systems are based on ionization chambers and requires high voltage biases *** ****. This study investigates on the measurements of the electron beam current emitted by a medical electron linear accelerator using the power exchange of the beam current with a passive resonant cavity ***** placed at the output interface of the accelerator. The cavity is magnetically coupled with a coaxial transmission line loaded on a microwave envelope detector and its output signal has been documented while receiving several electron currents. This paper shows the complete equivalency, in terms of global performance, of the current revelation performed by exploiting the cavity-beam interaction principle with the classical technology, based on ionization chambers, however without need of high voltage. The most important point is that the resonant cavity system, by measuring the beam current, gives a direct measurement of a physical observable quantity directly related with the dose deposed by the beam.
* EN 60601-2-1, 2009.
** A.P. Turner, 1979.
*** V.L. Uvarov, 1997.
**** M. Ruf∗, 2014.
***** J.B. Rosenzweig, 2003

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MOPTY002

Bunch Length Measurement of Femtosecond Electron Beam by Monitoring Coherent Transition Radiation

electron, detector, gun, linac

940

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultrashort electron bunches with durations of femtoseconds and attoseconds are essential for time-resolved measurements, including pulse radiolysis and ultrafast electron microscopy. However, generation of the ultrashort electron bunches is commonly difficult because of bunch length growth due to space charge effect, nonlinear momentum dispersion and so on. Several bunch length measurement methods for the ultrashort electron beams have also been considered so far, which have not been established yet. In this study, the femtosecond electron beams were generated using a laser photocathode radio-frequency gun linac and a magnetic bunch compressor. The bunch length measurement was carried out using a Michelson interferometer based on monitoring coherent transition radiation (CTR), which is characterized by square modulus of the Fourier transform of the longitudinal bunch distribution. Analyzing the experimentally obtained interferograms of CTR, the electron beams with the average duration of 5 fs were generated and measured successfully at the condition of bunch charge of 1 pC. Consideration of the longitudinal bunch shapes was also carried out using the Kramers-Kronig relation.

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MOPTY016

Study of Diamond Detector Application at the Front End of a High Intensity Hadron Accelerator

detector, cavity, hadron, proton

972

G. Ren, D.H. He, W. Li, Y. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
M. Zeng
Tsinghua University, Beijing, People's Republic of China

Diamond detectors function as beam loss or luminosity monitors for high energy accelerators, such as LHC, Babar, etc. Because of regular detectors‘ insufficient protection of the front end, diamond detectors owning significant characteristics, like time resolution in the nanosecond range, radiation hardness and negligible temperature dependence. Thus, diamond detectors have been becoming promising candidates for detecting BLMs of fully super-conducting hadron accelerator, such as C-ADS, FRIB. In this paper, the sensitivity of diamond detectors was simulated by Monte Carlo program FLUKA and GEAN4. Meanwhile, we tested the performance of a new prototype of CVD diamond detector, and compared it with Si-PIN and Bergoz detectors at the storage ring of the HLS II. The results of the diamond detector were consistent with other two detectors well. More evaluation of diamond detectors in low energy radiation field are ongoing.

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MOPTY034

Distributed Beam Loss Monitor Based on the Cherenkov Effect in Optical Fiber

electron, positron, beam-losses, storage-ring

1004

Yu. Maltseva, F.A. Emanov, A.V. Petrenko, V.G. Prisekin
BINP SB RAS, Novosibirsk, Russia
F.A. Emanov
NSU, Novosibirsk, Russia
A.V. Petrenko
CERN, Geneva, Switzerland

A distributed beam loss monitor based on the Cherenkov effect in optical fiber has been implemented for the VEPP5 electron and positron linacs and the 510 MeV damping ring at the Budker INP. The monitor operation is based on detection of the Cherenkov radiation generated in optical fiber by means of relativistic particles created in electromagnetic shower after highly relativistic beam particles (electrons or positrons) hit the vacuum pipe. The main advantage of the distributed monitor compared to local ones is that a long optical fiber section can be used instead of a large number of local beam loss monitors. In our experiments the Cherenkov light was detected by photomultiplier tube (PMT). Timing of PMT signal gives the location of the beam loss. In the experiment with 20 m long optical fiber we achieved 3 m spatial resolution. To improve spatial resolution optimization and selection process of optical fiber and PMT are needed and according to our theoretical estimations 0.5 m spatial resolution can be achieved. We also suggest similar techniques for detection of electron (or positron) losses due to Touschek effect in storage rings.

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MOPTY036

Radiation of a Bunch Moving in the Presence of a Bounded Planar Wire Structure

vacuum, diagnostics, electronics, electromagnetic-fields

1007

V.V. Vorobev, S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Three-dimensional* and planar** periodic structures can be used for non-destructive diagnostics of charged particle bunches. Here we consider the semi-infinite planar structure comprised of thin conducting parallel wires. If the period of the structure is much less than the typical wavelength of the electromagnetic field, then the structure's influence can be described with help of the averaged boundary conditions***. We study radiation of a charged particle bunch with small transversal size and arbitrary longitudinal one in two cases: (i) the bunch moves orthogonally to the grid at some distance from the edge and (ii) it moves along the edge of the grid. The problems are solved analytically. In both cases the bunch generates a surface wave which contains the information about the size of the bunch. The shape of the surface waves is similar to the radiation generated in the presence of 3D periodical wire structures*, however planar structure is simpler for use in accelerating system. Some typical numerical results for bunches of various shapes are given.
* V.V. Vorobev et al., Phys. Rev. Let., 108, 184801 (2012);
** A.V. Tyukhtin et al., Phys. Rev. ST AB (in press).
*** M.I. Kontorovich et al., Electrodynamics of Grid Structures (Moscow, 1987).

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MOPTY046

Personnel Safety Systems for the European Spallation Source

PLC, target, controls, neutron

1036

S.L. Birch, A. Nordt, D. Paulic
ESS, Lund, Sweden

Providing and assuring safe conditions for personnel is a key parameter required to operate the European Spallation Source (ESS). The ESS will be responsible for developing all of the facility personnel safety related systems. All of these systems will be developed by the Integrated Control Systems Division (ICS) and all will be designed, manufactured, commissioned and operated in accordance with the IEC61508 standard, with regard to functional safety for Electrical/Electronic and Programmable Electronic (E/E/PE) safety related systems. This paper describes the ESS Personnel safety system’s scope, strategy, initial design requirements, and methodology but also provides an update of the system design progress so far.

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MOPTY054

Fibre Monitoring System for the Beam Permit Loops at the LHC and Future Evolution of the Beam Interlock System

monitoring, operation, diagnostics, interface

1054

C. García-Argos, R. Denz, S. Gabourin, C. Martin, B. Puccio, A.P. Siemko
CERN, Geneva, Switzerland

The optical fibres that transmit the beam permit loop signals at the CERN accelerator complex are deployed along radiation areas. This may result in increased attenuation of the fibres, which reduces the power margin of the links. In addition, other events may cause the links to not function properly and result in false dumps, reducing the availability of the accelerator chain and affecting physics data taking. In order to evaluate the state of the fibres, an out-of-band fibre monitoring system is proposed, working in parallel to the actual beam permit loops. The future beam interlock system to be deployed during LHC long shutdown 2 will implement online, real-time monitoring of the fibres, a feature the current system lacks. Commercial off-the-shelf components to implement the optical transceivers are proposed whenever possible instead of ad-hoc designs.

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MOPTY058

Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam

detector, electron, experiment, beam-losses

1069

O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.

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MOPTY070

Online RadFET Reader for Beam Loss Monitoring System

EPICS, controls, network, interface

1097

C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Wu
NSRRC, Hsinchu, Taiwan

To investigate the beam loss and its distribution during operation of synchrotron light sources at NSSRC, a sixteen-channel readout box is designed and implemented to read the threshold voltage of the RadFETs installed at accelerator tunnel. To simplify the design, the reader plays a role of remote I/O for EPICS IOC. The IOC collects voltage from readers distributed in the accelerator to deduce the integrated dose and dose rate. User interface is shown in the control console for real-time display and the archived data are processed off-line.

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MOPTY072

Beam Loss Study of TLS Using RadFETs

injection, storage-ring, controls, booster

1103

C.H. Huang, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Wu
NSRRC, Hsinchu, Taiwan

To realize the beam loss during the operation of Taiwan light source, P-type radiation-sensing field-effect transistors are setup around the storage ring. A sixteen-channel readout box is used to read the threshold voltage of the radiation-sensing field-effect transistors during irradiation. The beam loss distribution and mechanism at the injection period, decay mode and top up injection for routing operation will be studied in this report.

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MOPTY074

Preliminary Beam Test of Synchrotron Radiation Monitoring System at Taiwan Photon Source

synchrotron, storage-ring, booster, synchrotron-radiation

1109

C.Y. Liao, Y.-S. Cheng, J. -Y. Chuang, K.T. Hsu, S.Y. Hsu, H.P. Hsueh, K.H. Hu, C.K. Kuan, C.Y. Wu
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a third generation 3 GeV synchrotron light facility. The synchrotron radiation from a dipole can be used to observe the beam parameters. The synchrotron radiation monitor (SRM) systems were designed and implemented for the booster synchrotron and storage ring. The SRM for the booster synchrotron can serve to diagnose the energy ramping process. The beam size decreases when the energy increases was observed. In the storage ring, the streak camera was preferred to observe the beam behaviour of the consecutive bunches. The bunch length and longitudinal instability were observed. The preliminary beam test results are summarized in this report.

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MOPTY080

A Multi-band Single Shot Spectrometer for Observation of mm-Wave Bursts at Diamond Light Source

detector, storage-ring, synchrotron, synchrotron-radiation

1126

A. Finn, P. Karataev
JAI, Egham, Surrey, United Kingdom
G. Rehm
DLS, Oxfordshire, United Kingdom

Micro-bunch instabilities (MBI) have been detected at many light sources across the world. The radiation bursts produced as a result of this instability occur in the millimetre wavelength regime. In order to understand more about the mechanism of MBI and improve the accuracy of simulations, more information is needed about the dynamics and spectral content of the radiation. A single shot spectrometer has therefore been developed to investigate this instability at Diamond Light Source. Due to their low noise, ultra-fast response and excellent sensitivity, Schottky detector diodes are employed. Currently, seven Schottky detectors are in place covering a range of 33-750 GHz. Unlike previous measurements at Diamond, each of the Schottky detectors has been characterised thus allowing the results obtained to be more easily compared to simulations. In this paper, we present the calibration of each Schottky detector in the spectrometer, the first results of tests with beam, as well as future plans for the spectrometer.

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MOPWI004

Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation

electron, experiment, laser, optics

1150

R.B. Fiorito, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.G. Shkvarunets
UMD, College Park, Maryland, USA

Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office.
Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.

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MOPWI016

Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA

laser, electron, linac, optics

1181

A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy.
The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps*, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available.
*A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.

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MOPWI018

New Hadron Monitor By Using A Gas-Filled RF Resonator

electron, plasma, hadron, proton

1189

K. Yonehara, A.V. Tollestrup, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
G. Fasce
CNI, Roma, Italy
G. Flanagan, R.P. Johnson
Muons, Inc, Illinois, USA

It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.

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MOPWI029

Electron Bombardment of ZnTe EO Bunch Charge Detector for Signal Lifetime Studies in Radiation Environment

electron, lattice, detector, laser

1220

J.E. Williams, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
S.V. Benson, S. Zhang
JLab, Newport News, Virginia, USA

Electro-optic detection of bunch charge distribution utilizing the nonlinear Pockel's and Kerr effect of materials has been implemented at various facilities as a method of passive detection for beam preservation throughout characterization. Most commonly, the inorganic II-VI material ZnTe is employed due to it's strong Pockel's EO effect and relatively high temporal resolution (~90 fs). Despite early exploration of radiation damage on ZnTe in exploration of semi-conductor materials in the 1970's, full characterization of EO response over radiation lifetime has yet to be performed. The following poster presents a method for ZnTe crystal characterization studies throughout radiation exposure at various energies and dosages by analyzing the changes in index of refraction including bulk uniformity, and THz signal response changes.

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MOPWI035

Characterization of Visible Synchrotron Radiation Polarization at SPEAR3

polarization, synchrotron, synchrotron-radiation, diagnostics

1240

W.J. Corbett, A.M. Kiss
SLAC, Menlo Park, California, USA
M.J. Boland
The University of Melbourne, Melbourne, Victoria, Australia
C.L. Li
East China University of Science and Technology, Shanghai, People's Republic of China

Schwinger's equations predict the angular- and spectral distribution of synchrotron radiation across a wide band of the electromagnetic spectrum. Using a visible-light diagnostic beam line, it is possible to characterize the electric field polarization state as a function of vertical observation angle and compare with theory. Complications include accounting for - and π-mode transmission factors at mirror surfaces and precise alignment of the polarizing optics with the principle beam axes. The Stokes parameters are measured and beam polarization ellipse reported.

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MOPWI046

eDT and Model-based Configuration of 12 GeV CEBAF

operation, controls, linac, synchrotron

1259

D.L. Turner
JLab, Newport News, Virginia, USA

Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This poster will discuss model-driven setup of CEBAF for the 12GeV era, focusing on the elegant Download Tool (eDT). eDT is a new operator tool that generates magnet design setpoints for various machine energies and pass configurations. eDT was developed in the effort towards a process for reducing machine configuration time and reproducibility by way of an accurate accelerator model.

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TUYB2

Accelerator Physics in ERL Based Polarized Electron Ion Collider

electron, ion, linac, luminosity

1296

Y. Hao
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

Slides TUYB2 [14.101 MB]

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TUAC1

Beam Instrumentation and Diagnostics for High Luminosity LHC

synchrotron, diagnostics, pick-up, collimation

1349

O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler
CERN, Geneva, Switzerland

The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.

Slides TUAC1 [4.490 MB]

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TUBC3

Recent Results from FEL seeding at FLASH

FEL, electron, laser, operation

1366

J. Bödewadt, S. Ackermann, R.W. Aßmann, N. Ekanayake, B. Faatz, G. Feng, I. Hartl, R. Ivanov, T. Laarmann, J.M. Müller, T. Tanikawa
DESY, Hamburg, Germany
S. Ackermann, Ph. Amstutz, A. Azima, M. Drescher, L.L. Lazzarino, C. Lechner, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Roßbach
Uni HH, Hamburg, Germany
K.E. Hacker, S. Khan, R. Molo
DELTA, Dortmund, Germany

The free-electron laser facility FLASH at DESY operates since several years in SASE mode, delivering high-intensity FEL pulses in the extreme ultra violet and soft x-ray wavelength range for users. In order to get more control of the characteristics of the FEL pulses external FEL seeding has proven to be a reliable method to do so. At FLASH, an experimental setup to test several different external seeding methods has been installed since 2010. After successful demonstration of direct seeding at 38 nm, the setup is now being operated in HGHG and later EEHG mode. Furthermore, other studies on laser induced effects on the electron beam dynamics have been performed. In this contribution, we give an overview of recent experimental results on FEL seeding at FLASH.

Slides TUBC3 [6.651 MB]

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TUPWA008

Mixing and Space-Charge Effects In Free-Electron Lasers

laser, electron, FEL, space-charge

1410

E.A. Peter, A. Endler, F.B. Rizzato
IF-UFRGS, Porto Alegre, Brazil
A.P.B. Serbeto
UFF, Niterói - RJ, Brazil

Funding: This work was supported by CNPq and FAPERGS, Brazil, and by the Air Force Office of Scientific Research (AFOSR), USA, under the Grant No. FA9550-12-1-0438
Free-electron lasers are devices which efficiently convert the kinetic energy from a relativistic electron beam into electromagnetic radiation, amplifying an initial small sign. The present work revisits the subject of mixing, saturation and space-charge effects in free-electron lasers. Use is made of the compressibility factor, which proves to be a helpful tool in the related systems of charged beams confined by static magnetic fields. The compressibility allows to build a semi-analytical model and to perform analytical estimates of the elapsed time until the onset of mixing, which in turn allows to estimate the saturated amplitude of the radiation field. In addition, the compressibility helps to pinpoint space-charge effects and the corresponding transition from Compton to Raman regimes. The semi-analytical model and the particles simulations are compared, exhibiting a good agreement.*
* E. Peter, A. Endler, F. B. Rizzato, and A. Serbeto, Phys. Plasmas 20,
123104 (2013).
** E. Peter, A. Endler, and F. B. Rizzato, Phys. Plasmas 21, 113104 (2014)

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TUPWA017

Collimation scheme for the ESRF Upgrade

lattice, collimation, shielding, beam-losses

1434

R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White
ESRF, Grenoble, France

The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.

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TUPWA021

A New Method to Generate Ultrashort and Coherent Pulses of Short-Wavelength Synchrotron Radiation

laser, electron, synchrotron, storage-ring

1448

S. Khan
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (contract 05K13PE3)
A laser-based method to generate ultrashort pulses of synchrotron radiation in electron storage rings is coherent harmonic generation (CHG) using two undulators to produce coherent radiation at harmonics of the initial laser wavelength by microbunching. The bunching factor and thus the pulse intensity, however, decreases exponentially with increasing harmonic order. Echo-enabled harmonic generation (EEHG), proposed in 2009 as FEL seeding scheme*, can be used to produce short synchrotron radiation pulses at higher harmonics, but requires three undulators in a straight section. In this paper, a less space-consuming method based on seeding with intensity-modulated laser pulses is introduced, which also has the potential of significant bunching factors at high harmonics.
* G. Stupakov, PRL 102 (2009), 074801.

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TUPWA022

Characterization and Optimization of Ultrashort and Coherent VUV Pulses at the DELTA Storage Ring

laser, electron, synchrotron, undulator

1452

S. Khan, F.H. Bahnsen, M. Bolsinger, S. Hilbrich, M. Huck, M. Höner, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, G. Shayeganrad, P. Ungelenk
DELTA, Dortmund, Germany
H. Huck
DESY Zeuthen, Zeuthen, Germany

Funding: Work supported by BMBF (05K13PE3 and 05K13PEC), DFG (INST 212/236-1 FUGG) and the Land NRW
At DELTA, a 1.5-GeV synchrotron light source operated by the TU Dortmund University, a source for coherent and ultrashort vacuum-ultraviolet (VUV) and terahertz (THz) pulses is now in operation. The VUV source is based on a laser-induced energy modulation and coherent harmonic generation (CHG). A subsequently developing dip in the longitudinal electron distribution gives rise to coherent THz radiation. Recent results regarding the optimization of the laser-electron interaction and characterization of the CHG pulses are presented.

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TUPWA043

Non-interferometric Spectral Analysis of Synchrotron Radiation in the THz regime at ANKA

synchrotron, synchrotron-radiation, electron, storage-ring

1509

J.L. Steinmann, M. Brosi, E. Bründermann, C.M. Caselle, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, M. Schuh, M. Schwarz, P. Schönfeldt, P. Schütze
KIT, Karlsruhe, Germany
J.L. Hesler
Virginia Diodes Inc., Charlottesville, USA

Interferometry is the quasi-standard for spectral measurements in the THz- and IR-range. The frequency resolution, however, is limited by the travel range of the interferometer mirrors. Therefore, a resolution in the low megahertz range would require interferometer arms of about 100 m. As an alternative, heterodyne measurements provide a resolution in the Hertz range, an improvement of 6 orders of magnitude. Here we present measurements done at ANKA with a VDI WR3.4SAX, a mixer that can be tuned to frequencies from 220 GHz to 330 GHz and we show how the bunch filling pattern influences the amplitude of specific frequencies.

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TUPWA048

Radiative Cooled Target for the ILC Polarized Positron Source

target, positron, vacuum, photon

1526

A. Ushakov
University of Hamburg, Hamburg, Germany
F. Dietrich, S. Riemann, T. Rublack
DESY Zeuthen, Zeuthen, Germany
P. Sievers
CERN, Geneva, Switzerland

Funding: Work supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Optimization", contract number 19XL7IC4
The target for the polarized positron source of the future International Linear Collider (ILC) is designed as wheel of 1 m diameter spinning with 2000 revolutions per minute to distribute the heat load. The target system is placed in vacuum since exit windows would not stand the load. In the current ILC design, the positron target is assumed to be water-cooled. Here, as an alternative, radiative cooling of the target has been studied. The energy deposition in the target is the input for ANSYS simulations. They include the temperature evolution as well as the corresponding thermo-mechanical stress in the target components. A principal design is suggested for further consideration.

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TUPWA061

Analyses of Light's Orbital Angular Momentum from Helical Undulator Harmonics

undulator, polarization, photon, emittance

1563

S. Sasaki, A. Miyamoto
HSRC, Higashi-Hiroshima, Japan
M. Hosaka, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Katoh, T. Konomi
UVSOR, Okazaki, Japan

Funding: Partially supported by the Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, and supported by the Joint Studies Program of the Institute for Molecular Science.
The phenomenon of higher harmonic radiation from a helical undulator carrying orbital angular momentum (OAM)* attracts a great deal of attention because this novel property may be used as a new probe for synchrotron radiation science** that would be performed in a diffraction limited light source facility such as the APS-II. Although a diffraction limited x-ray source does not yet exist, the 750 MeV UVSOR-III is already a diffraction limited light source in the UV region. In this ring, a tandem-aligned double-APPLE undulator system similar to that in BESSY-II*** is installed for FEL and coherent light source experiments. Using this set-up, we observed spiral interference patterns between two different harmonic radiations with a scanning fiber multi-channel spectrometer and a CCD camera placed at the end of BL1U Beamline. By these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical prediction for every mode in the right or left circular polarization. The rotation of an interference pattern by rotating a polarizer was also observed.
* S. Sasaki and I. McNulty, Phys. Rev. Lett. 100, 124801, 2008.
** M. VanVeenendaal and I. McNulty, Phys. Rev. Lett. 98, 157401 (2007).
*** J. Bahrdt, et al., Phys. Rev. Lett. 111, 034801, 2013.

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TUPWA070

CST Simulations of THz Cherenkov Smith-purcell Radiation from Corrugated Capillary

simulation, electron, polarization, laser

1594

K. Lekomtsev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
P. Karataev
JAI, Egham, Surrey, United Kingdom
A. Ponomarenko, A.A. Tishchenko
MEPhI, Moscow, Russia

Recent advances in generation of femtosecond pre-bunched beams have a potential to generate coherent THz radiation occurring via combination of Smith-Purcell radiation (SPR) and Cherenkov radiation (ChR) generated in a corrugated capillary. This mechanism was studied theoretically *. LUCX accelerator at High Energy Accelerator Research Organisation (KEK) has been upgraded by introducing fs Ti:Sa laser system and it is currently generating short tens of fs electron bunches **. In this report we present EM simulations of Ch.SPR generated in a corrugated channel in infinite dielectric and in a dielectric corrugated capillary. CST PIC solver is used as a simulation tool. It was earlier used for simulation of Transition radiation ***. Intensity dependencies of ChR and SPR peaks as functions of the capillary radius and the corrugation depth are compared with the theoretical investigation *. Output of THz radiation from the dielectric capillary with a radiation reflector is simulated.
* A.A. Ponomarenko et. al, NIMB 309 (2013) 223-226.
** M. Fukuda et. al, NIMA 637 (2011) S67.
*** K.V. Lekomtsev et. al, J. Phys.: Conf. Ser. 517, (2014) 012016.

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TUPWA072

Coherent Thomson Scattering Radiation Generated by using PEHG

electron, laser, scattering, undulator

1601

S. Chen, K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
S. Huang
PKU, Beijing, People's Republic of China

In this paper, we present the coherent Thomson scattering of a long wavelength laser with ultrashort electron slices. The ultrashort electron slices are generated by the longitudinal bunch density modulation method of PEHG. Coherent radiation with ultrashort pulse length is generated in EUV regime by this method.

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TUPJE001

Design of Wavelength Tunable Coherent X-Ray Source

electron, target, optics, emittance

1604

J. Hyun
Sokendai, Ibaraki, Japan
K. Endo
TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan
K. Hayakawa, Y. Hayakawa, T. Sakai, T. Tanaka
LEBRA, Funabashi, Japan
I. Sato
Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan
M. Satoh, M. Yoshida
KEK, Ibaraki, Japan

KEK, Nihon University and TOYAMA CO., Ltd. have been developing the compact shieldless coherent X-ray source that can change the X-ray energy (3-25keV). This X-ray is the Parametric X-ray radiation (PXR) generated by relativistic charged particles passed through a single crystal. It has features that are monochromaticity, coherence and diffraction large angle for the incident beam. These indicate to the possibility for the application to the medical treatment and diagnosis. Furthermore, we try to reduce the radiation which is mainly generated when the high energy beam is damped. This system consists of an accelerating, a decelerating structure and four bending magnets (theta: 90 degree). These structures are operated under low temperature to get the high Q-value for long beam pulse. PXR is generated by colliding with a single crystal after electron beam is accelerated up to 75 MeV. The bunch passed through the crystal is transported into a decelerator structure and then is decelerated to 3 MeV there. Q-magnets are arranged that dispersion function is zero except arc sections. We calculated the beam transport, PXR intensity and emittance blow up. We'll report these details.

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TUPJE004

Narrow Band Coherent Edge Radiation at UVSOR-III

electron, experiment, laser, storage-ring

1613

M. Hosaka, O. Oodake, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
S. Bielawski, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
M. Katoh, T. Konomi, J. Yamazaki
UVSOR, Okazaki, Japan
H. Zen
Kyoto University, Kyoto, Japan

Edge radiation can be an interesting new light source because of its property that the radiation is well collimated and is radially polarized. We are developing coherent light sources in the THz region at UVSOR-III storage ring. We have already succeeded in producing a narrow band coherent THz radiation by manipulating the interaction of a relativistic electron bunch with an amplitude modulated laser with. Recently a simplified tentative beamline for detection of the edge radiation is installed at downstream of a short straight section of UVSOR-III. Coherent radiation from electron bunches after the interaction with the amplitude modulated laser is observed. Detailed measurements of polarizations and special distribution of the radiation are underway. The latest status of the study will be reported.

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TUPJE007

Measurement of Temporal Electric Field of Electron Bunch using Photoconductive Antenna

electron, laser, linac, polarization

1623

K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

A temporal electric field profile, which is a radially polarized terahertz (THz) pulse from an electron bunch, was measured by a large-aperture photoconductive antenna (PCA) with micro-structured concentric electrodes* for the detection of THz pulses. Photo-induced charge carriers were generated by irradiation of femtosecond laser pulses on semiconductor plane of the electrodes on the PCA. Time-domain measurement of coherent transition radiation (CTR) was conducted by the measurement of electric-field-induced current output from the PCA with sweeping the timing of the laser irradiation. The measurements on femtosecond electron bunches of 32 MeV and >80 pC will be reported.
* K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).

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TUPJE010

Study of Cs-Te Photocathode for RF Electron Gun

electron, gun, vacuum, scattering

1632

S. Matsuzaki, M. Nishida, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
H. Iijima
Tokyo University of Science, Tokyo, Japan

At Waseda University, we have been studying high quality electron beam with an rf electron gun. In recent accelerator study and application researches, high quality electron beam are strongly required. Photocathode is a key component to generate higher quality electron beam. Cs-Te photocathode shows high quantum efficiency (Q.E.) (~10%) and has long life time (~several months). From 2013, we built a photocathode evaporation chamber and started photocathode study. In this study, our purpose is to clarify their property and to establish an ideal evaporation recipe. We succeeded in producing high quality Cs-Te photocathode, and electron beam generated by our Cs-Te photocathode shows high charge (4.6nC/bunch) and high Q.E. (1.74%) in our rf electron gun. Furthermore, we found a Q.E. recovery after Cs deposition process and it causes higher Q.E. than usual due to, we believe, Cs deposition quantity or Cs deposition speed. Thus we are now surveying the optimum Cs evaporation parameters. In this conference, we will report a detail of our photocathode development system, the latest progress of optimization study of Cs-Te photocathode and future plans.
Work supported by Cooperative and Supporting Program for Researches and Educations in Universities and NEDO(New Energy and Industrial Technology Development Organization.

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TUPJE016

COHERENT SYNCHROTRON RADIATION FIELD AND THE ENERGY LOSS IN A WAVY BEAM

electron, wakefield, synchrotron, synchrotron-radiation

1650

D.R. Xu, H. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

The synchrotron radiation will be coherent when the wavelength of the radiation can be compared with the bunch length. There are two approaches to produce Coherent Synchrotron Radiation (CSR) on a storage ring. One is to compress the bunch length, the other one is to produce a wavy beam which has high spatial repetition along the longitudinal direction. The latter one can expand the radiation frequency range of a light source. However, CSR can bring nonlinear effect which brings in extra instability. The Lienard-Wiechert potentials in three-dimensional space may have very complicated forms. The most common way to investigate CSR is numerical method. This paper try to use a simple model to obtain energy loss of the electrons in theory.

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TUPJE017

The Generation of Highly Intense THz Radiation based on Smith-Purcell Radiation

electron, factory, gun, cathode

1654

Y.F. Xu, Z.G. He, Q.K. Jia, W.W. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China

A photocathode RF gun can generate trains of THz subpicosecond electron bunches by illuminating the cathode with trains of laser pulses. Let this electron bunches passes close to the surface of a lamellar grating, THz radiation will be emitted, which is the so-called Smith-Purcell Radiation (SPR). If the lamellar grating has a narrow groove, this radiation will be narrow-band. By choosing suitable parameter, the SPR frequency can be resonant with the electron bunches frequency, and then generate high intense, narrow band THz radiation.

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TUPJE018

On-axis Injection Scheme for Ultimate Storage Ring with Double RF Systems

injection, synchrotron, emittance, storage-ring

1657

B.C. Jiang, S.Q. Tian, M.Z. Zhang, Q.L. Zhang, Z.T. Zhentang
SINAP, Shanghai, People's Republic of China

An on-axis injection scheme using double RF systems for an ultimate storage ring which holds very small dynamic aperture is proposed. By altering RF voltages, empty RF buckets can be created which will be used for on-axis injection. After bunches are injected, a reverse voltage altering process is performed and the injected bunches can be longitudinally dumped to the main buckets.

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TUPJE019

Operating Cascaded High-gain Harmonic Generation with Double-pulse Electron Beams

electron, laser, FEL, simulation

1661

Z. Wang, C. Feng, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
L. Yu
BNL, Upton, Long Island, New York, USA

Cascaded high gain harmonic generation (HGHG) is the primary candidate for the generation of high power, full temporal coherent radiation at the wavelength of nanometer. However, the experimental results at the existing facility show large fluctuation of the output energy pulse at the second stage of cascading. In this paper, we study the scheme of double-pulse electron beams, which is helpful to increase the stability of pulse energy against the timing jitter. The method to generate double-pulse electron beams is shown in the paper and comparison between double-pulse scheme and standard cascaded HGHG is present base on three-dimensional start-to-end simulation to give a straightforward image on the obviously improvement of the FEL stability.

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TUPJE033

A Research on the Reverse Tapering Method to Gain High Power Polarized Photon Beam with Fixed Wavelength

undulator, resonance, electron, simulation

1678

C.H. Shim, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Han, Y.W. Parc
PAL, Pohang, Kyungbuk, Republic of Korea

Polarization of soft X-ray photon can be controlled with combination between planar undulators and helical ones. We need to give a reverse tapering to the planar undulators to make microbunching in the electron beam while the linearly polarized radiation power is depressed. In this case, however, resonance wavelengths in each planar undulator are different each other. Therefore, proper initial undulator parameter and tapering strength parameter have to be chosen to obtain high power polarized photon beam with fixed wavelength. In this research, method for deciding suitable reverse tapering is presented using simulation results of PAL-XFEL soft X-ray case with 10 GeV electron beam energy.

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TUPJE037

Magnetic Measurements of the NSLS-II Insertion Devices

insertion, electron, insertion-device, undulator

1693

M. Musardo, D.A. Harder, C.A. Kitegi, T. Tanabe
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
This paper presents the results and the recent progress in the magnetic measurements of the insertion devices (IDs) for the National Synchrotron Light Source-II (NSLS-II) at Brookhaven National Laboratory (BNL). A detailed analysis of the magnetic measurements is carried out for various IDs with particular attention at the influence of the magnetic field errors on the devices spectral performance. Several specific details of the measurements and the recent results from IDs commissioning are presented.

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TUPJE047

Design Studies for an Upgrade of the SLS Storage Ring

emittance, lattice, storage-ring, operation

1724

A. Streun, M. Aiba, M. Böge, M.P. Ehrlichman, A. Saá Hernández
PSI, Villigen PSI, Switzerland

An upgrade of the Swiss Light Source (SLS) would replace the existing storage ring by a low aperture multibend achromat lattice providing an emittance of about 100–200 pm at 2.4 GeV, while maintaining the hall, the beam lines and the injector. Since emittance scales inversely cubically with the number of lattice cells, an SLS upgrade is challenged by the comparatively small ring circumference of only 288 m. A new concept for a compact low emittance lattice is based on longitudinal gradient bending magnets for emittance minimization and on anti-bends (i.e bends of opposite field polarity) to disentangle dispersion and horizontal beta function in order to provide the optimum matching to the longitudinal gradient bends while minimizing the contribution to chromaticity.

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TUPJE050

Design of a Resonant Transition Radiation Source in the soft X-ray Range

photon, electron, resonance, vacuum

1735

P. Wang, K.C. Leou
NTHU, Hsinchu, Taiwan
N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

Resonant transition radiation (RTR) can be generated from multi-layer structures when they are driven by relativistic electron beams. In consideration of using the NSRRC 90 MeV photoinjector as driver, we examined the feasibility of generating narrow-band soft x-rays from various multi-layer structures. Based on analytical theory, the expected angular-spectral distribution and photon yield of these radiators are calculated and compared.

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TUPJE060

Development of Advanced Fourth Generation Light Sources for the Accelerator Science Laboratory

electron, simulation, cavity, laser

1765

T. Chanwattana, R. Bartolini, A. Seryi
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom
E. Tsesmelis
CERN, Geneva, Switzerland

The John Adams Institute for Accelerator Science (JAI) has proposed the realisation of the Accelerator Science Laboratory (ASL) at the University of Oxford as a facility for the development of advanced compact light sources enabling accelerator science research and applications. The installation of a compact light source in the ASL is planned with two options for the accelerating technologies. Firstly, a conventional RF based accelerator is considered to be a driver for a short pulse THz coherent synchrotron radiation (CSR). The other option focusses on the radiation produced by a Laser Plasma Accelerator (LPA) advanced accelerator technique that will provide the possibility to shorten the length of the beamline. This paper presents results of the studies on beam dynamics for both options of compact light sources in the ASL.

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TUPJE065

Multi-Bunch Stability Analysis of the Advanced Photon Source Upgrade Including the Higher-Harmonic Cavity

HOM, damping, impedance, simulation

1784

L. Emery, T.G. Berenc, M. Borland, R.R. Lindberg
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Multi-bunch stability simulations were done for the very-low-emittance hybrid seven-bend-achromat (H7BA) lattice proposed for the Advanced Photon Source (APS) upgrade. The simulations, performed using tracking code elegant, were meant to determine whether the long-term wakefields of the higher-order modes (HOMs) of the main 352-MHz cavities will produce an instability. The multi-particle simulations include the important effects of the Higher-Harmonic Cavity (HHC) and the longitudinal impedance of the new vacuum chamber. These realistic simulations show that the HHC provides additional damping in the form of the Landau damping. Still, the HOMs may likely produce a multi-bunch instability which can be cured with more effective HOM damping or a longitudinal feedback system.

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TUPJE073

Results of the Magnetic Tuning of 2.8 m Long Vertically Polarizing Undulator with the Dynamic Compensation of Magnetic Forces

undulator, FEL, electron, free-electron-laser

1809

I. Vasserman
ANL, Argonne, Ilinois, USA

A novel undulator prototype with a horizontal magnetic field and dynamic compensation of magnetic forces has been recently developed at the APS as a part of the LCLS-II R&D program. This undulator should meet stringent requirements for any LCLS-II insertion device. These requirements include limits on the field integrals and phase errors for all operational gaps, and the reproducibility and accuracy of the gap settings. Extensive mechanical testing has resulted in a performance that meets the requirements on the undulator gap setting. The magnetic tuning has been accomplished by applying a set of magnetic shims. As a result, the satisfactory performance of the undulator prototype has been demonstrated.
The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory. Argonne, Contract No. DE-AC02-06CH11357.

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TUPJE081

Model of Dark Current in SRF Linac

cavity, linac, electron, quadrupole

1834

A.I. Sukhanov, A. Saini, N. Solyak, I.S. Tropin
Fermilab, Batavia, Illinois, USA

Currently, few linacs based on 9-cell TESLA-type SRF cavities are being designed or bult, including XEFL, LCLS-II and ILC. Dark current electron generated by field emission in SRF cavities can be captured and accelerated in the linac up to hundreds MeV before they removed by focusing magnets. Lost dark current electrons interact with the materials surrounding SRF cavities and magnets, produce electromagnetic showers and contribute to the radiation in the linac tunnel. In this paper we present a model of dark current in a linac based on TESLA cavities. We show preliminary results of the simulation applied to ILC main linac.

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TUPMA001

Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source

optics, injection, photon, lattice

1840

C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallén, W. Wan
LBNL, Berkeley, California, USA

Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics.

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TUPMA007

Numerical Investigation of a Cascaded Longitudinal Space-Charge Amplifier at the Fermilab's Advanced Superconducting Test Accelerator

space-charge, bunching, simulation, impedance

1850

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

In a cascaded longitudinal space-charge amplifier (LSCA), initial density noise in a relativistic e-beam is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. This type of amplification process was shown to potentially result in large final density modulations * compatible with the production of broadband electromagnetic radiation. The technique was recently demonstrated in the optical domain **. In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA). We especially explore the properties of the produced broadband radiation. Our studies have been conducted with an effective three-dimensional space-charge algorithm.
* Dohlus, M. et al. Proc. SPIE 8779. doi:10.1117/12.2017369
** Marinelli, A. et al. Phys. Rev. Lett. 110, 264802 (2013)

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TUPMA008

Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance

impedance, space-charge, simulation, detector

1853

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such "microbunching instabilities" were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body "Barnes-Hut" algorithm * to simulate the 3D space charge force in the beam combined with Elegant ** and explore the limitation of the 1D model often used.
* Barnes, J. & Hut, P., Nature 324, 446-449, 1986.
** Borland, M., Advanced Photon Source LS-287, 2000.

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TUPMA021

Optimization of an Improved SASE (iSASE) FEL

FEL, lattice, undulator, simulation

1881

L. Gupta
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
K. Fang, J. Wu
SLAC, Menlo Park, California, USA

Funding: Supported by US DOE FWP-2013-SLAC-100164 and DOE SULI.
In order to improve free electron laser technology for the future LCLSII at SLAC, a new strategy for creating radiation with increased temporal coherence is under development. The improved Self-Amplified Spontaneous Emission (iSASE) FEL utilizes phase shifters which allow for the spontaneously emitted radiation to interact with and stimulate more electrons to radiate coherently. Five phase shifters were simulated, with 34 normal-conducting undulators and focusing-defocusing quadrupoles as an LCLSII FEL lattice using the FEL software Genesis 1.3. Two general schemes, one providing a total phase shift of arbitrary distribution, the other providing a sequential or distributed phase shift, were simulated and optimized using a simulated annealing algorithm. The results suggest that the phase shifters must provide a total shift comparable to the bunch length, and the shifts must be distributed with one large shift, followed by smaller shifts.
* J. Wu, A. Marinelli, C. Pellegrini, Proc. FEL2012, pp. 237, Japan (2012).
** J. Wu, et al., Proc. IPAC2013, pp. 2068, China (2013).

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TUPMA023

Two-Dimensional Calculation of Channeling Radiation Spectrum for High-Brightness Hard X-Ray Production

electron, lattice, ion, brightness

1888

W.D. Rush, J. Shi
KU, Lawrence, Kansas, USA

The channeling radiation spectrum is calculated without using the one-dimensional approximation in the planar channeling radiation model or the single-string approximation in the axial channeling radiation model. The obtained spectrum of the two-dimensional channeling radiaiton is significantly different from those previously calculated with the approximations. The calculation presented here is of the channeling radiation experiments conducted at Fermilab Advanced Superconducting Test Accelerator (ASTA) photoinjector with electron beam energies of 20-50 MeV and a diamond target. The computational method developed in this work can be applied to general cases of different crystals and beams with different energy and emittances.

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TUPMA030

Narrowband Continuously Tunable Radiation in the 5 to 10 Terahertz Range by Inverse Compton Scattering

electron, laser, photon, scattering

1901

Z. Wu, K. Fang, M.-H. Wang, J. Wu
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy under Grants DE-AC02-76SF00515, DE-FG02-13ER41970 and by DARPA Grant N66001-11-1-4199.
5 to 10 THz has recently become the frontier of THz radiation sources development, pushed by the growing interests of spectroscopy and pump-probe material study in this frequency range. This spectrum “Gap” lies in between the several THz range covered by Electro-Optical crystal based THz generation, and the tens of THz range covered by the difference frequency generation method. The state-of-the-art EO crystal THz source using tilted pulse front technique has been able to reach ~ 100 MV/m peak field strength, large enough to be used in an inverse Compton scattering process to push these low energy photons to shorter wavelengths of the desired 5-10 THz range. The required electron beam energy is within 1~2 MeV, therefore a compact footprint of the whole system. The process would occur coherently granted the electron beam is bunched to a fraction of the radiation wavelengths (several microns). A system operating at KHz or even MHz repetition rate is possible given the low electron energy and thus low RF acceleration gradient required. This work will explore the scheme with design parameters and simulation results.

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TUPMA036

First e-/Photon Commissioning Results for the GlueX Experiment/Hall D at CEBAF

photon, detector, acceleration, target

1916

M.D. McCaughan, J. F. Benesch, Y. Roblin, T. Satogata
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Experimental Hall D, with flagship experiment GlueX, was constructed as part of the 12 GeV CEBAF upgrade. A new magnetically extracted electron beam line was installed to support this hall. Bremsstrahlung photons from retractable radiators, are delivered to the experiment through a series of collimators following a long drift to allow for beam convergence. Coherent Bremsstrahlung generated by interaction with a diamond radiator will achieve a nominal 40% linear polarization and photon energies between 8.5 and 9 GeV from 12.1 GeV electrons, which are then tagged or diverted to a medium power 60kW electron dump. The expected photon flux is 107-10⁸ Hz. This paper discusses the experimental line design, commissioning experience gained since first beam in spring 2014, and the present results of beam commissioning by the experiment.

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TUPMA041

On the Characterization of a CCR Source

brightness, FEL, impedance, emittance

1926

A.V. Smirnov
RadiaBeam, Santa Monica, California, USA

Funding: US Department of Energy, contract # DE- SC-FOA-0000760
Peak and spectral brightness of a resonant long-range wakefield extractor are evaluated. It is shown that the brightness is dominated by beam density within the slow wave structure and antenna gain of the outcoupling. Far field radiation patterns and brightness of circular and high-aspect-ratio planar radiators are compared. A possibility to approach the diffraction limited brightness is demonstrated. Role of group velocity in designing of the Cherenkov source is emphasized. The approach can be applied for design and characterization of various structure-dominated sources (e.g., wakefield extractors with gratings or dielectrics, or FEL-Cherenkov combined sources) radiating into a free space using an antenna (from microwave to far infra-red regions). The high group velocity structures can be also effective as energy dechirpers and for diagnostics of microbunched relativistic electron beams.

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TUPMA042

THz Radiation Generation in a Multimode Wakefield Structure

wakefield, experiment, electron, linac

1929

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, D. Wang, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571
A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.

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TUPMA055

Analysis of Possible Beam Losses in the NSLS II Storage Ring

dipole, storage-ring, shielding, electron

1956

S. Seletskiy, R.P. Fliller, W. Guo, S.L. Kramer, Y. Li, B. Podobedov, T.V. Shaftan, W.H. Wahl, F.J. Willeke
BNL, Upton, Long Island, New York, USA

The NSLS-II accelerators are installed within radiation shielding walls that are designed to attenuate the radiation generated from an assumed beam loss power to a level of <0.5mrem/h at the outer surface of the bulk shield walls. Any operational losses greater than specified level are expected to be addressed by installing supplemental shielding near the loss point in order to attenuate the radiation outside the shield wall to the design level. In this paper we report the analysis of the electron beam mis-steering in the NSLS-II storage ring for the determination of supplementary shielding.

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TUPMA056

Analysis of Possible Beam Losses in the NSLS II BSR Transfer Line

booster, storage-ring, shielding, extraction

1959

S. Seletskiy, R.P. Fliller, W. Guo, S.L. Kramer, Y. Li, B. Podobedov, T.V. Shaftan, W.H. Wahl, F.J. Willeke
BNL, Upton, Long Island, New York, USA

The NSLS-II accelerators are installed within 0.8 – 1 m thick radiation shielding walls. The safety considerations require attenuating the radiation generated from possible electron beam losses to a level of <0.5mrem/h at the outer surface of the bulk shield walls. Any operational losses greater than specified level shall be addressed by installing supplemental shielding near the loss point. In this paper we discuss simulation studies that identified potential beam loss locations. Results of these studies were used for identification of imposed radiation risks and for specification of the supplemental shielding design necessary to mitigate those risks.

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TUPMA057

Commissioning of Active Interlock System for NSLS II Storage Ring

storage-ring, synchrotron, synchrotron-radiation, photon

1962

S. Seletskiy, C. Amundsen, J. Choi, J.H. De Long, K.M. Ha, C. Hetzel, H.-C. Hseuh, Y. Hu, P. Ilinski, S.L. Kramer, Y. Li, M.A. Maggipinto, J. Mead, D. Padrazo, T.V. Shaftan, G. Shen, O. Singh, R.M. Smith, W.H. Wahl, G.M. Wang, F.J. Willeke, L. Yang
BNL, Upton, Long Island, New York, USA

The NSLS-II storage ring is protected from possible damage from insertion devices (IDs) synchrotron radiation by a dedicated active interlock system (AIS). It monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope. In this paper we describe functional details of the AIS and discuss our experience with commissioning of the AIS for the first six IDs installed in the storage ring.

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TUPHA003

Sputter Growth of Alkali Antimonide Photocathodes: An in Operando Materials Analysis

cathode, target, emittance, gun

1965

J. Smedley, K. Attenkofer, M. Gaowei, J. Sinsheimer, J. Walsh
BNL, Upton, Long Island, New York, USA
H. Bhandari
Radiation Monitoring Devices, Watertown, USA
Z. Ding, E.M. Muller
SBU, Stony Brook, New York, USA
H.J. Frisch
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
H.A. Padmore, S.G. Schubert, J.J. Wong
LBNL, Berkeley, California, USA

Funding: Work supported by U.S. DoE, under KC0407-ALSJNT-I0013 and SBIR grant # DE-SC0009540. NSLS was supported by DOE DE-AC02-98CH10886, CHESS is supported by NSF & NIH/NIGMS via NSF DMR-1332208
Alkali antimonide photocathodes are a strong contender for the cathode of choice for next-generation photon sources such as LCLS II or the XFEL. These materials have already found extensive use in photodetectors and image intensifiers. However, only recently have modern synchrotron techniques enabled a systematic study of the formation chemistry of these materials. Such analysis has led to the understanding that these materials are inherently rough when grown through traditional sequential deposition; this roughness has a detrimental impact on the intrinsic emittance of the emitted beam. Sputter deposition may provide a path to achieving a far smoother photocathode, while maintaining adequate quantum efficiency. We report on the creation and vacuum transport of a K2CsSb sputter target, and its use to create an ultra-smooth (sub nm roughness) cathode with a 2% quantum efficiency at 532 nm.

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TUPTY001

Interaction Region for a 100 TeV Proton-Proton Collider

shielding, quadrupole, interaction-region, dipole

1996

R. Martin, R. Tomás
CERN, Geneva, Switzerland
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, FCC-hh, running at center-of-mass energies of up to 100 TeV, pushing the energy frontier of fundamental physics to a new limit. At a circumference of 80-100 km, this machine is planned to use the same tunnel as FCC-ee, a proposed 90-350 GeV high luminosity electron-positron collider. This paper presents the design progress and technical challenges for the interaction region of FCC-hh.

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TUPTY023

Lessons Learned From the First Long Shutdown of the Lhc and Its Injector Chain

operation, superconducting-magnet, collider, hardware

2050

K. Foraz, M.B.M. Barberan Marin, M. Bernardini, J. Coupard, N. Gilbert, D. Hay, S. Mataguez, D.J. Mcfarlane, E. Vergara Fernandez
CERN, Geneva, Switzerland

The First Long Shutdown (LS1) of the LHC and its Injector chain, which started in February 2013, was completed by the first quarter 2015. A huge number of activities have been performed; this paper reviews the process of the coordination of LS1 from the preparatory phase to the testing phase. The preparatory phase is a very important process: an accurate view of what is to be done, and what can be done is essential. But reality is always different, the differences between what was planned and what was done will be described. The paper will recall the coordination, reporting and decisional processes, highlighting points of success and points to be improved in terms of general coordination, in-situ coordination, safety coordination, logistics and resource management.

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TUPTY031

Tools for Flexible Optimisation of IR Designs with Application to FCC

synchrotron, synchrotron-radiation, simulation, detector

2072

H. Burkhardt
CERN, Geneva, Switzerland
M. Boscolo
INFN/LNF, Frascati (Roma), Italy

The interaction regions of future high-luminosity colliders require well balanced designs, which provide both for a very high luminosity and at the same time keep backgrounds and radiation at tolerable levels. We describe a set of flexible tools, targeted at providing a first evaluation of losses in the interaction region as part of the design studies, and their application to FCC.

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TUPTY053

Roadmap towards High Accelerator Availability for the CERN HL-LHC Era

luminosity, operation, beam-losses, target

2143

A. Apollonio, M. Brugger, L. Rossi, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

High Luminosity-LHC is the future upgrade of the LHC that aims at delivering an integrated luminosity of 3000 fb-1 over about 10 years of operation, starting from 2025. Significant modifications [1] will be implemented to accelerator systems, including new superconducting magnets, crab cavities, superconducting links, new collimators and absorbers based on advanced materials and design and additional cryo-plants. Due to the limit imposed by the number of simultaneous events at the experiments (pile-up) on peak luminosity, the latter will be levelled to 5*1034 cm^-2s⁻¹. The target integrated luminosity can only be achieved with a significant increase of the total available time for beam collisions compared to the 2012 LHC run, despite a beam current that is planned to double the nominal 0.58 A. Therefore one of the key figures of merit to take into account for system upgrades and new designs is their impact on the accelerator availability. In this paper the main factors affecting LHC availability will be discussed and predictions on the impact of future system upgrades on integrated luminosity presented. Requirements in terms of the maximum allowed number of dumps for the main contributing systems to LHC unavailability will be derived.

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TUPTY060

The FCC-ee Study: Progress and Challenges

collider, interaction-region, synchrotron, optics

2165

M. Koratzinos
DPNC, Genève, Switzerland
S. Aumon, C. Cook, A. Doblhammer, B. Härer, B.J. Holzer, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
M. Boscolo
INFN/LNF, Frascati (Roma), Italy
L.E. Medina Medrano
UGTO, Leon, Mexico
U. Wienands
SLAC, Menlo Park, California, USA

The FCC (future circular collider) study represents a vision for the next large project in high energy physics, comprising a 80-100 km tunnel that can house a future 100TeV hadron collider. The study also includes a high luminosity e⁺e⁻ collider operating in the centre-of-mass energy range of 90-350 GeV as a possible intermediate step, the FCC-ee. The FCC-ee aims at definitive electro-weak precision measurements of the Z, W, H and top particles, and search for rare phenomena. Although FCC-ee is based on known technology, the goal performance in luminosity and energy calibration make it quite challenging. During 2014 the study went through an exploration phase and during the next three years a conceptual design report will be prepared.

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TUPTY062

FCC-hh Hadron Collider - Parameter Scenarios and Staging Options

luminosity, operation, damping, proton

2173

M. Benedikt, B. Goddard, D. Schulte, F. Zimmermann
CERN, Geneva, Switzerland
M.J. Syphers
NSCL, East Lansing, Michigan, USA
M.J. Syphers
Fermilab, Batavia, Illinois, USA

FCC-hh is a proposed future energy-frontier hadron collider, based on dipole magnets with a field around 16 T installed in a new tunnel with a circumference of about 100 km, which would provide proton collisions at a centre-of-mass energy of 100 TeV, as well as heavy-ion collisions at the equivalent energy. The FCC-hh should deliver a high integrated proton-proton luminosity at the level of several 100 fb^-1 per year, or more. The challenges for operating FCC-hh with high beam current and at high luminosity include the heat load from synchrotron radiation in a cold environment, the radiation from collision debris around the interaction region, and machine protection. In this paper, starting from the FCC-hh design baseline parameters we explore different approaches for increasing the integrated luminosity, and discuss the impact of key individual parameters, such as the turnaround time. We also present some injector considerations and options for early hadron-collider operation.

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TUPTY072

A New ILC Positron Source Target System Using Sliding Contact Cooling

target, vacuum, positron, undulator

2196

W. Gai, D.S. Doran, R.A. Erck, G.R. Fenske, V.J. Guarino, W. Liu
ANL, Argonne, Illinois, USA

The R&D of the baseline positron source target for ILC is still ongoing after TDR due to the uncertainty of rotating vacuum seal and water cooling system of the fast spinning target wheel. Different institutes around the globe have proposed different approaches to tackle this issue. A spinning target wheel system with sliding contact cooling has been proposed by ANL. The proposed system eliminated the needs of rotating vacuum seal by using magnet bearings and vacuum compatible motor driven solid spinning wheel target. The energy deposited from positron production process is taken away via sliding cooling pads sliding against the spinning wheel. Details about this new target system are presented in this paper.

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TUPWI005

Proton Irradiations of Micro-TOM Red Hairy Roots to Mimic Space Conditions

proton, experiment, controls, framework

2249

M. Vadrucci, A. Ampollini, G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
E. Benvenuto, A. Desiderio, S. Massa, C. Snels, M.E. Villani
ENEA Casaccia, Roma, Italy

Funding: Radiation Sources Laboratory UTAPRAD Department ENEA C.R. Frascati Via E. Fermi, 45 00044 Frascati (RM), Italy ENEA
The purpose of the BIOxTREME project, launched by ENEA and funded by ASI (Italian Space Agency), is to formulate new biological drugs having a stimulant activity on the immune system finalizing the production for a ready to use resource in Bioregenerative Life Support Systems (BLSSs) for space missions with extended durations, in deep space, and with multiple crews. One of the project tasks is to study the effects of physical insults on plants, simulating cosmic environment on production platforms by static magnetic fields, microgravity and ionizing radiation. In order to examine the biological effects, to test plant radio-resistance and to build dose-response curves we carried out proton irradiations of a tomato cultivar Micro-Tom red hairy roots with the TOP-IMPLART accelerator at the ENEA Frascati Research center. The biological samples were placed in a holder specially made in a movable real-time monitoring chamber calibrated in dose. The fluence-homogeneity measurements over the sample and the calibration of the monitoring system were performed using GafChromic EBT3 films. The paper describes the experimental set-up and reports the preliminary results.

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WEXC1

Machine and Personnel Protection for High Power Hadron Linacs

linac, hadron, ion, controls

2418

M. Ikegami
FRIB, East Lansing, Michigan, USA

Machine and personnel safety are increasingly important for high power hadron linacs as involved beam power increases. Design requirements and characteristic features of machine protection system and personnel protection system for operating and proposed high power hadron linacs, such as J-PARC, SNS, FRIB, ESS, and IFMIF, are reviewed.

Slides WEXC1 [9.859 MB]

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WEXC3

Improving the Energy Efficiency of Accelerator Facilities

klystron, operation, neutron, synchrotron

2428

M. Seidel
PSI, Villigen PSI, Switzerland
R. Gehring
KIT, Karlsruhe, Germany
E. Jensen
CERN, Geneva, Switzerland
T.I. Parker
ESS, Lund, Sweden
P.J. Spiller, J. Stadlmann
GSI, Darmstadt, Germany

New particle accelerator based research facilities tend to be much more productive, but often in coincidence with much higher energy consumption. The total energy consumption of mankind is steeply rising, while some European countries decided to terminate nuclear power generation and to switch to renewable energy production. Also the CO2 problem gives rise to new approaches for energy production and in all strategies the efficiency of utilization of electrical energy plays an important role. For the public acceptance of particle accelerator projects it is thus very important to optimize them for best utilization of electrical energy and to show these efforts to funding bodies and to the public. Within the European accelerator development program Eucard-2 we organise a network EnEfficient that aims at improving the energy efficiency of accelerators. In this paper we give some background information on the political situation, we describe the power flow in accelerator facilities and we give examples for developments of efficient accelerator systems, such as magnets, RF generation and beam acceleration, heat recovery and energy management.

Slides WEXC3 [2.611 MB]

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WEPWA008

Measuring the Self-modulation Instability of Electron and Positron Bunches in Plasmas

plasma, electron, cavity, positron

2506

P. Muggli, O. Reimann
MPI-P, München, Germany
E. Adli, V.K.B. Olsen
University of Oslo, Oslo, Norway
J. Allen, S.J. Gessner, S.Z. Green, M.J. Hogan, M.D. Litos, B.D. O'Shea, V. Yakimenko
SLAC, Menlo Park, California, USA
L.D. Amorim
IST, Lisboa, Portugal
G. Andonian, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi, O. Williams
UCLA, Los Angeles, California, USA
N.C. Lopes, L.O. Silva, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal

The self-modulation instability (SMI) * can be used to transform a long, charged particle bunch into a train of periodically spaced shorter bunches. The SMI occurs in a plasma when the plasma wake period is much shorter than the bunch length. The train of short bunches can then resonantly drive wakefields to much larger amplitude that the long bunch can. The SMI will be used in the AWAKE experiment at CERN, where the wakefields will be driven by a high-energy (400GeV) proton bunch. ** However, most of the SMI physics can be tested with the electron and positron bunches available at SLAC-FACET. *** In this case, the bunch is ~10 plasma wavelengths long, but can drive wakefields in the GV/m range. FACET has a meter-long plasma **** and is well equipped in terms of diagnostic for SMI detection: optical transition radiation for transverse bunch profile measurements, coherent transition radiation interferometry for radial modulation period measurements and energy spectrometer for energy loss and gain measurement of the drive bunch particles. The latest experimental results will be presented.
* N. Kumar et al., PRL 104, 255003 (2010)
** AWAKE Collaboration, PPCF 56 084013 (2014)
*** J. Vieira et al., PoP 19, 063105 (2012)
**** S.Z. Green et al., PPCF 56, 084011 (2014)

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WEPWA019

Development of Accelerator-driven Compact Neutron Sources

neutron, target, proton, status

2535

K. Hirota, G. Ichikawa, M. Kitaguchi, Y. Kiyanagi, H.M. Shimizu, K. Tsuchida, A. Uritani, K. Watanabe
Nagoya University, Nagoya, Japan

Neutron is a very good probe to investigate the inner structure of materials. The large neutron facilities like J-PARC MLF and SNS were constructed in this decade, and ESS facility are start to construct. These large facilities are very good tools to study in academic field. But the construction cost is increasing and it is hard to construct at many facilities. And also it is hard to get long beam time. One of the solution of these problems are constructing Compact Accelerator-driven Neutron Source (CANS). We will present the current situation of CANS and the status of the facility of Nagoya University.

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WEPWA024

Development of a C-band RF Gun with a Coniferous-tree-type Carbon Nanostructure Field Emission Cathode

cavity, cathode, gun, electron

2545

Y. Taira, H. Kato, R. Kuroda, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan

A C-band RF gun for compact radiation sources such as a high energy x-ray and a terahertz radiation is developed at AIST, which is designed to work at the frequency of 5.3 GHz*. A coniferous-tree-type carbon nanostructure (CCNS) is used for a field emission cathode in the C-band RF gun. A graphene sheet composed of carbon has a coniferous form, and the tip has a nanometer-size tubular structure that becomes thicker on the substrate side**. Owing to this configuration, the CCNS has a large field enhancement factor, and is considered to be more stable in high electric fields than Carbon nanotubes. We have fabricated the C-band RF gun of the single cell cavity. Emission current depending on the electric field strength on the CCNS cathode surface was measured. When the electric field strength was 30 MV/m, the total charge per a macro pulse was 30 nC. After applying a stronger electric field, a decline of the field enhancement factor was observed. We will present the experimental result of the field emission measurement of the CCNS and the simulation result of a beam trajectory using a C-band RF gun of a multi cell cavity.
* Y. Taira et al., Nucl. Instr. and Meth. Phys. Res. B 331 (2014) 27.
** R. Suzuki, Synthesiology 2 (3) (2009) 221.

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WEPWA037

Beam-Driven Terahertz Source Based on Open Ended Waveguide with a Dielectric Layer: Rigorous Approach

vacuum, interface

2578

S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin, V.V. Vorobev
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: Grant of the President of Russian Federation (No. 6765.2015.2) and Russian Foundation for Basic Research (No. 15-32-20985, 15-02-03913).
Terahertz frequency radiation (0.1-10 THz) is a promising tool for a number of scientific and practical applications. One promising scheme to obtain powerful and efficient THz emission is usage of beam-driven dielectric loaded structures [1]. Recently we have considered the problem where the microbunched ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation [2]. To investigate the applicability of utilized approximations, we analyze here the case of orthogonal end of a waveguide with continuous filling. However, presented rigorous approach can be generalized for waveguide with vacuum channel. We use the combination of Wiener-Hopf technique and tailoring technique. The infinite linear system for magnitudes of reflected waveguide modes is obtained and solved numerically. We present typical field distributions over the aperture and typical radiation patterns in the Fraunhofer zone.
* S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012).
** S.N. Galyamin et al., Opt. Express. 22(8), 8902 (2014).

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WEPWA038

Mode Transformation in Waveguide with Transversal Boundary Between Vacuum and Partially Dielectric Area

vacuum, wakefield, acceleration, electron

2581

A.A. Grigoreva, T.Yu. Alekhina, S.N. Galyamin, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

We consider the mode transformation in a circular waveguide with a transversal boundary between a vacuum part and a part with a cylindrical dielectric layer and a vacuum channel. It is assumed that an incident mode can be both propagating and evanescent. Analysis is carried out with the using the mode decomposition technique. Numerical algorithm for calculating the mode transformation at an arbitrary channel radius is also developed. Typical dependences for the reflection and transmission coefficients on the channel radius are presented and discussed.

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WEPWA040

Generation and Radiation of PHz Ring-Like Electron-Pulse Train

electron, cathode, acceleration, bunching

2587

F.H. Chao, C.H. Chen, Y.-C. Huang
NTHU, Hsinchu, Taiwan
P.J. Chou
NSRRC, Hsinchu, Taiwan

In a superradiant FEL, the constructive interference of the radiation fields from a periodic electron-pulse train rapidly increases the radiation power at the harmonics of the pulse frequency with a narrow spectrum bandwidth. To generate radiation in the X-ray spectrum, the corresponding pulse frequency of the pre-bunched electron beam should be few tens or even few hundreds PHz. The repetition rate of electron pulses generated from an ordinary RF photoinjector is usually at 10-100 Hz. Even though a superconducting RF accelerator could further increase the repetition rate of electron pulses to few MHz, it is far below the pulse frequency required for a superradiant XFEL. In this paper, we study a technique to generate a PHz ring-like electron-pulse train from an RF photoinjector with a spatially modulated driver laser and a structured photocathode. Our simulation in PARMELA confirms the feasibility of generating such a structured electron-pulse train from the photoinjector. We present our study on the beam dynamics of the structured electron-pulse train during acceleration and the radiation behavior of it in the far field in comparison with that of an ordinary electron beam.

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WEPWA056

The Sinuous Target

target, proton, electron, lattice

2630

R.M. Zwaska
Fermilab, Batavia, Illinois, USA

We report on the concept for a target material comprised of a multitude of interlaced wires of small dimension. This target material concept is primarily directed at high-power neutrino targets where the thermal shock is large due to small beam sizes and short durations; it also has applications to other high-power targets, particularly where the energy deposition is great or a high surface area is preferred. This approach ameliorates the problem of thermal shock by engineering a material with high strength on the microscale, but a very low modulus of elasticity on the mesoscale. The low modulus of elasticity is achieved by constructing the material of spring-like wire segments much smaller than the beam dimension. The intrinsic bends of the wires will allow them to absorb the strain of thermal shock with minimal stress. Furthermore, the interlaced nature of the wires provides containment of any segment that might become loose. We will discuss the progress on studies of analogue materials and fabrication techniques for sinuous target materials.

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WEPWA060

Interaction of a Volumetric Metamaterial Structure with an Electron Beam

electron, wakefield, acceleration, coupling

2640

X.Y. Lu, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: The U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0010075 and the Air Force Office of Scientific Research under MURI Grant Number FA550-12-1-0489.
A volumetric metallic metamaterial structure with a cubic unit cell is introduced. The unit cells can naturally fill all of space without additional substrates or waveguides. The structure can support a negative longitudinal electric mode that can couple to an electron beam. The dispersion characteristics of the unit cell are modeled by the effective medium theory with spatial dispersion. The theory also predicts the correct resonant frequencies of the emitted radiation excited by an electron beam traversing the structure. In the wakefield simulations, a backward radiation pattern is observed. The proposed metamaterial can be applied to beam diagnostics and wakefield acceleration.

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WEPWA068

Simulation of Laser Pulse Driven Terahertz Generation in Inhomogeneous Plasmas

plasma, laser, simulation, vacuum

2661

C.M. Miao, T.M. Antonsen
UMD, College Park, Maryland, USA
J. Palastro
Icarus Research, Inc., Bethesda, Maryland, USA

Intense, short laser pulses propagating through inhomogeneous plasma can ponderomotively drive THz radiation. Here we consider a transition radiation mechanism (TRM) for THz generation as a laser pulse crosses a plasma boundary. Full format PIC simulations and theoretical analysis are conducted demonstrating that TRM results in low frequency, broad band, coherent THz radiation. The effect of a density ramp is also considered and shown to enhance the radiated energy.

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WEPJE033

The Progress of Funnelling Gun High Voltage Condition and Beam Test

cathode, gun, electron, high-voltage

2735

E. Wang, I. Ben-Zvi, D.M. Gassner, R.F. Lambiase, W. Meng, A.I. Pikin, T. Rao, B. Sheehy, J. Skaritka
BNL, Upton, Long Island, New York, USA
M.A. Ackeret, J.R. Pietz
Transfer Engineering and Manufacturing, Inc, Fremont, California, USA
E. Dobrin, R.C. Miller, K.A. Thompson, C. Yeckel
Stangenes Industries, Palo Alto, California, USA
O.H. Rahman
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A prototype of a high average current polarized electron funneling gun as an eRHIC injector has been built at BNL. The gun was assembled and tested at Stangenes Incorporated. Two beams were generated from GaAs photocathodes and combined by a switched combiner field. We observed the combined beams on a YAG crystal and measured the photocurrent by a Faraday cup. The gun has been shipped to Stony Brook University and is being tested there. In this paper we will describe the major components of the gun and recent beam test results. High voltage conditioning is discussed as well.

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WEPMA003

Vacuum System Design for the Sirius Storage Ring

vacuum, storage-ring, dipole, synchrotron

2744

R.M. Seraphim, O.R. Bagnato, R.O. Ferraz, H.G. Filho, G.R. Gomes, M. Nardin, R.F. Oliveira, B.M. Ramos, A.R.D. Rodrigues, M.B. Silva, T.M. da Rocha
LNLS, Campinas, Brazil

Sirius is a 3 GeV 4th-generation light source under construction by the Brazilian Synchrotron Light Laboratory (LNLS). Sirius will have a low emittance storage ring, 0.28 nm-rad, based on 20 cells of a highly compact lattice – 5-bend achromat (5BA). This lattice concept leaves very little space for components and therefore requires narrow vacuum chambers with tight mechanical tolerances. Most of the storage ring vacuum chambers will be made of OFS copper and have a circular cross section with inner diameter of 24 mm and a wall thickness of 1 mm. The unused synchrotron radiation will be distributed along the water cooled walls of the chambers. Due to the small conductance of the chambers, the vacuum pumping will be based on distributed concept and then non-evaporable getter (NEG) coating will be extensively used, with more than 95% of the chambers being coated. In this paper, we present an overview of the storage ring vacuum system and the main vacuum chambers fabrication developments.

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WEPMA005

Particularities of the ARIEL e-Linac Cryogenic System

cryomodule, linac, cryogenics, TRIUMF

2750

I.V. Bylinskii, G.W. Hodgson, D. Kishi, S.R. Koscielniak, A. Koveshnikov, R.E. Laxdal, R.R. Nagimov, D. Yosifov
TRIUMF, Vancouver, Canada

Funding: Canada Foundation for Innovation, British Columbia Knowledge Development Fund, and National Research Council Canada.
The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separation and Acceleration (ISAC) facility at TRIUMF [1]. A key part of the ARIEL project is a 10 mA 50 MeV continuous-wave superconducting radiofrequency (SRF) electron linear accelerator (e-linac). The 1.3 GHz SRF cavities are cooled by liquid helium (LHe) at 2 K [2]. The 4 K 2 K LHe transition is achieved onboard of each cryomodule by the cryoinsert containing counterflow heat exchanger augmented with JT valve [3]. Air Liquide LHe cryoplant provides 4 K LHe to cryomodules. After successful commissioning of the cryoplant, 2 K sub-atmospheric (SA) system and cryomodules, the ultimate integration test confirmed stable operation of two cryomodules comprising two 9 cell SRF cavities. Particularities of this cryogenic system include conservative design of the oil removal system, original design heat exchanger in the SA pumping system, hermetic SA pumps, inline full SA flow purifier, multipurpose recovery/purification compressor, modular LHe distribution system, top-loaded design cryomodules, and overall radiation resistant design. The paper presents details of these features as well as integration tests results.

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WEPMA015

Water-cooled Thin Walled Beam Pipes of the Fast Ramping Storage Ring ELSA

synchrotron, electron, dipole, synchrotron-radiation

2780

P. Hänisch, W. Hillert, B. Neff
ELSA, Bonn, Germany

At the Electron Stretcher Facility ELSA of Bonn University thin walled beam pipes are in use to reduce eddy current loss to a minimum. The operation of the accelerator places high demands on the beam pipes like static stress because of the inner vacuum and additional one-sided thermal stress caused by synchrotron radiation. A first generation of thin walled beam pipes had been developed and manufactured during the construction of the stretcher ring in 1985. These pipes were successfully in operating stage the following ten years. The beam pipes had a wall thickness of 0.3mm, a length of 3m, and a bending radius of ca. 10.5m. Special pipes with a sideway branch for synchrotron radiation experiments have been manufactured in the same assembly dimension. In the course of an intensity upgrade, a second generation of beam pipes has been developed in 1995. To reduce the thermal stress caused by the synchrotron radiation an internal water cooling was mounted. In this contribution the design and manufacturing principles of the thin walled beam pipes with water cooling are presented.

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WEPMA045

Energy Deposition and DPA in the Superconducting Links for the HiLumi LHC project at the LHC Interaction Points

neutron, photon, luminosity, simulation

2865

F. Broggi, A. Bignami, C. Santini
INFN/LASA, Segrate (MI), Italy
A. Ballarino, F. Cerutti, L.S. Esposito
CERN, Geneva, Switzerland

Funding: The work is part of HiLumi LHC Design Study, partly funded by the European Commission, GA 284404, and included in the High Luminosity LHC project.
In the framework of the upgrade of the LHC machine, the powering of the LHC magnets foresees the removal of the power converters and distribution feedboxes from the tunnel and its location at the surface[1]. The Magnesium Diboride (MgB2) connecting lines in the tunnel will be exposed to the debris from 7+7 TeV p-p interaction. The Superconducting (SC) Links will arrive from the surface to the tunnel near the separation dipole, at about 80 m from the Interaction Point at IP1 and IP5. The Connection Box (where the cables of the SC Links are connected to the NbTi bus bar) will be close to the beam pipe. The debris and its effect on the MgB2 SC links in the connection box (energy deposition and displacement per atom) are presented. The effect of thermal neutrons on the Boron consumption and the contribution of the lithium nucleus and the alpha particle on the DPA are evaluated. The results are normalized to an integrated luminosity of 3000 fb-1, value that represents the LHC High Luminosity lifetime. The dose delivered to the SC Links is found to be below the damage limit. Further studies are necessary to correlate the induced displacement per atom to the superconducting properties.

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WEPMA059

Degassing of Kicker Magnet by In-situ Bake-out Method

vacuum, kicker, plasma, shielding

2911

J. Kamiya, Y. Hikichi, M. Kinsho, N. Ogiwara
JAEA/J-PARC, Tokai-mura, Japan

New method of in-situ degassing of the kicker magnet in the beam line has been developed. The heater and heat shielding panels are installed in the vacuum chamber in this method. The heater was designed considering the maintainability. The graphite was selected as the heater and the high melting point metals were used as the reflectors just near the heater. The thermal analysis and the temperature measurement with the designed heater was performed. The ideal temperature distribution for the kicker degassing was obtained. The outgassing of the graphite during rising the temperature was measured. The result showed that the outgassing was extremely suppressed by the first heating. This means the outgassing of the graphite heater was negligible as long as it is used in the beam line without exposure to the air.

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WEPMN017

High Power RF Radiation at W-band Based on Wakefields Excited by Intense Electron Beam

wakefield, electron, simulation, experiment

2960

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA

We report the experiment design and preliminary results on high power RF generation at W-band based on coherent wakefields from the metallic periodic structure of 91 GHz PETS (power extraction and transfer structure), excited by intense electron beam at the Argonne Wakefield Accelerator (AWA) facility. The recently output RF power is 0.7 MW, with 67 MeV, 1.4 nC single electron beam going through the structure. The RF pulse length is 3.4 ns. We measure the energy loss of electron beam as reference to the RF generation, which agrees well with the simulation results. Next run is to increase the output RF power with higher charge and to excite coherent wakefields with electron bunch train. The output RF peak power is expected to be ~100 MW and the electrical field gradient can reach up to 400 MV/m, with RF pulse duration adjustable from few ns to 30 ns when excited with 5~10 nC charge in a single bunch and up to 32 sub bunches in total.

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WEPMN023

Vacuum System of the Storage Ring of HLS-II

vacuum, storage-ring, synchrotron, synchrotron-radiation

2976

Y. Wang, L. Fan, Y.Z. Hong, X.T. Pei, J. Wang, W. Wei, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

HLS storage-ring has been operated for more than twenty-five years. In 2014 we began to upgrade the machine, which is called HLS-II. The emittance is reduced to 40 nmrad, five insertion devices are added and the injection energy increases to 800MeV. Now the machine commissioning has already been completed. The typical life time is 300 mins at 300mA, 800MeV. The average pressure of static and dynamic vacuum are below 2×10^-8 Pa and 1.2×10-7 Pa respectively. The design, installation and commissioning of the vacuum system of the storage ring are detailedly stated in this paper.

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WEPMN034

Electron Emission from Surface Roughness on Cavity in Low Temperature

electron, cavity, gun, vacuum

3003

H. Kim, H.J. Cha, S. Choi, W.K. Kim, G.-T. Park
IBS, Daejeon, Republic of Korea
Y. Chang
Hanshin University, Kyungki, Republic of Korea

Electron emission phenomenon from surface roughness on cavity is investigated. The distribution of the electric field from the surface roughness can be obtained on cavity surface. The field emission is calculated from the electric field distribution. The generalized electron emission from electric field and temperature effect is also calculated on the surface roughness of the cavity.

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WEPMN035

QWR and HWR Cryomodules for Heavy Ion Accelerator RAON

cryomodule, cavity, alignment, vacuum

3006

W.K. Kim, H.J. Cha, H. Kim, H.J. Kim, Y. Kim, M. Lee, G.-T. Park
IBS, Daejeon, Republic of Korea

The accelerator called RAON has five kinds of cryomodules such as QWR, HWR1, HWR2, SSR1 and SSR2. The QWR and HWR1 cryomodules are designed and fabricated. The cryomodules will be operated at 2 K and 4 K in order to operate the superconducting cavities. The static heat load of the system was analytically computed for each configuration. The functional requirement of the cryomodules and the static heat load measurement of the QWR and HWR1 cryomodules are presented in this research.

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WEPMN056

High Power Testing of the First Re-buncher Cavity for LIPAC

cavity, vacuum, electron, low-level-rf

3051

F. Toral, D. Gavela, I. Podadera, D. Regidor, M. Weber, C. de la Morena
CIEMAT, Madrid, Spain
B. Bravo, R. Fos, J.R. Ocampo, F. Pérez, A. Salom, P. Solans
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

Funding: This work is partially supported by the Spanish Ministry of Economy and Competitiveness under projects AIC-A-2011-0654 and the Agreement as published in BOE, 16/01/2013, page 1988
Two re-buncher cavities will be installed at the Medium Energy Beam Transport (MEBT) of the LIPAc accelerator, presently being built at Rokkasho (Japan). They are IH-type cavities with 5 gaps and will provide an effective voltage of 350 kV at 175 MHz for deuterons at 5 MeV. The first prototype has been designed at CIEMAT and built by the Spanish industry. The high power tests and RF conditioning have been successfully performed at the ALBA/CELLS RF laboratory. A solid state power amplifier, which has been developed by CIEMAT and its partner companies at Spain for the LIPAc RF System, has been used for the tests. The cavity has shown a performance according to calculations, regarding the dissipated power, peak temperatures and coupling factor. RF conditioning was started with a duty cycle of 3%, which was increased gradually till continuous wave (CW), which is the nominal working mode in LIPAc.

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WEPHA012

Synchrotron Radiation Distribution and Related Outgassing and Pressure Profiles for the HL-LHC Final Focus Magnets

photon, vacuum, synchrotron, synchrotron-radiation

3127

R. Kersevan
CERN, Geneva, Switzerland

The HL-LHC final focus area, from D2 to the interaction point, has been modelled based on the latest vacuum chamber geometry and orbits. The synchrotron radiation (SR) fans are computed using the Monte Carlo code SYNRAD⁺, in the dipole approximation regime. The angular and energy dependence of the reflectivity of the copper surfaces is considered, as well as the surface roughness. Once the SR distributions are computed, they are converted into outstanding profiles by using data available in literature. The test-particle Monte Carlo code Molflow+ is then used and the related pressure profiles and gas density distribution are computed. This allows an optimization of the pattern of the perforations on the tungsten-shielded beam screen proposed for this area. It is shown that the resultant gas density is below the limit dictated by the ATLAS and CMS detectors.

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WEPHA028

Power Saving Status at NSSRC

controls, synchrotron, operation, booster

3173

J.-C. Chang, W.S. Chan, Y.C. Chang, Y.F. Chiu, Y.-C. Chung, C.W. Hsu, K.C. Kuo, Y.-C. Lin, C.Y. Liu, Z.-D. Tsai, T.-S. Ueng
NSRRC, Hsinchu, Taiwan

National Synchrotron Radiation Research Center (NSRRC), Taiwan has completed the construction of the civil and utility system engineering of the Taiwan Photon Source (TPS) in 2014. The machine is in commission currently. The power consumption is much higher than ever. Currently, the contract power capacities of the Taiwan Light Source (TLS) and the TPS with the Taiwan Power Company (TPC) are 5.5 MW and 7.5 MW, respectively. The ultimate power consumption of the TPS is estimated about 12.5 MW. To cope with increasing power requirement in the near future, we have been conducting several power saving schemes, which include adjustment of supply air temperature according to the atmosphere enthalpy, replacement of old air conditioning unit (AHU), power consumption control by the operation of chillers, power factor improvement, and reduction of power consumption during long shutdown.

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WEPTY029

Measurements of Strontium Ferrite Hybrid Permanent Magnet Quadrupoles after Removal for the Fermilab NOvA Upgrade in 2012

permanent-magnet, quadrupole, dipole, injection

3331

O. Kiemschies
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
During the 2012 NOvA upgrade forty strontium ferrite hybrid permanent magnet quadrupoles from the injection, extraction and electron cooling regions of the Recycler accelerator, which had been measured in 2000 and subsequently installed in the tunnel, were replaced. The basic design of the quadrupoles * and expected decay rate ** are described in design documents. Nine of these magnets, of varying strength were measured in 2014. Measurements were made with a modified rotating coil in a fashion similar to their initial pre-installation measurements in 2000. The 2014 measurements are compared to the 2000 measurements and the expected decay. Many of these quadrupoles, as well as other strontium ferrite hybrid permanent magnets are still in operation in the Recycler and tranfer line, so understanding the rate at which the strength changes is significant to the future operation of the Recycler.
* Hybrid Permanent Quadrupoles for the. 8 GeV Transfer Line at Fermilab. (S.M. Pruss et al.)
** Time Evolution of Fields in Strontium Ferrite Permanent Magnets (J. T. Volk et al.)

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WEPTY031

Estimation of Cryogenic Heat Loads in Cryomodule due to Thermal Radiation

niobium, cryomodule, cavity, cryogenics

3338

A. Saini, V.A. Lebedev, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Cryogenic system is one of major cost drivers in high intensity superconducting (SC) continuous wave (CW) accelerators. Thermal radiations coming through the warm-ends of cryomodule and room temperature parts of the power coupler result in additional cryogenic heat loads. Excessive heat load in 2K environment may degrade overall performance of the cavity. In this paper we present studies performed to estimate additional heat load at 2K due to thermal radiation in 650 MHz cavity cryomodule in high energy section of PIP-II SC linac.

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WEPTY054

Grid Window Tests on an 805-MHz Pillbox Cavity

Windows, cavity, scattering, controls

3393

Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA
A. Moretti
Fermilab, Batavia, Illinois, USA

Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
Muon ionization cooling channel designs use pillbox shaped RF cavities for improved power efficiency and fine control over phasing of individual cavities. For minimum scattering of the muon beam, the ends should be made out of a small thickness of high radiation length material. Good electrical and thermal conductivity are required to reduce power dissipation and remove the heat efficiently. Thin curved beryllium windows with TiN coating have been used successfully in the past. We have built an alternative window set consisting of grids of tubes and tested these on a pillbox cavity previously used with both thin Be and thick Cu windows. The cavity was operated with a pair of grids as well as a single grid against a flat endplate.

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WEPTY064

Thermal-mechanical Analysis of the FRIB Nuclear Fragment Separator Dipole Magnet

dipole, quadrupole, target, cryogenics

3425

S.A. Kahn, A. Dudas, G. Flanagan
Muons, Inc, Illinois, USA
R.C. Gupta
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by the U.S. Department of Energy under Grant DE-SC-0006273
Dipole magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) are critical elements used to select the desired isotopes. These magnets are subjected to high radiation and heat loads. High temperature superconductors (HTS), which have been shown to be radiation resistant and can operate at 40 K where heat removal is substantially more efficient than 4.5 K where conventional superconductors such as NbTi and Nb3Sn operate, are proposed for the coils. The magnet coils carry large current and will be subjected to large Lorentz forces that must be constrained to avoid distortions of the coils. It is desirable to minimize the use of organic materials in the fabrication of this magnet because of the radiation environment. This paper will describe an approach to support the coils to minimize coil deformation and cryogenic heat loss.

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WEPTY073

Update on Nitrogen Doping: Quench Studies and Sample Analysis

cavity, niobium, vacuum, SRF

3450

D. Gonnella, F. Furuta, G.M. Ge, J.J. Kaufman, M. Liepe, J.T. Maniscalco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: U.S. Department of Energy, NSF
Recently, nitrogen-doping of niobium has emerged as a promising preparation method for SRF cavities to reach higher intrinsic quality factors than can be reached with typical cavity preparation. Nitrogen-doped cavities prepared at Cornell have shown quality factors higher than 4x10¹⁰ at 2.0 K and 16 MV/m. While Q results have been very exciting, a reduced quench field currently limits nitrogen-doped cavities with quench typically occurring between 15 and 25 MV/m. Here we report on recent results from Cornell on single-cell and 9-cell cavities, focusing on new preparations and maximum and critical fields. First we discuss results from over-doping niobium with nitrgoen, baking nitrogen-doped cavities at 120C, and doping with Argon. For a subset of these cavities we show results from quench studies that have been completed using temperature mapping. Finally, we present the first measurements of the higher critical field, Hc2, for nitrogen-doped niobium samples.

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WEPWI060

Cryogenic Test of Double Quarter Wave Crab Cavity for the LHC High Luminosity Upgrade

cavity, cryogenics, luminosity, higher-order-mode

3630

B. P. Xiao, S.A. Belomestnykh, I. Ben-Zvi, C. Cullen, L.R. Hammons, C. Marques, J. Skaritka, S. Verdú-Andrés, Q. Wu
BNL, Upton, Long Island, New York, USA
L. Alberty, R. Calaga, O. Capatina
CERN, Geneva, Switzerland
S.A. Belomestnykh, I. Ben-Zvi
Stony Brook University, Stony Brook, USA
Z. Li
SLAC, Menlo Park, California, USA

Funding: Work partly supported by US LARP, by US DOE under contract No. DE-AC02-05CH11231 and through BSA under contract No. DE-AC02-98CH10886. Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404.
A Proof-of-Principle (PoP) Double Quarter Wave Crab Cavity (DQWCC) was designed and fabricated for the Large Hadron Collider (LHC) luminosity upgrade. A vertical cryogenic test has been done at Brookhaven National Lab (BNL). The cavity achieved 4.5 MV deflecting voltage with a quality factor above 3×10⁹. We report the test results of this design.

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THXC2

Ion Beam Therapy with Ions Heavier than Protons: Performance and Prospects

ion, proton, neutron, shielding

3654

U. Linz
FZJ, Jülich, Germany

Starting from a short discussion on the pros and cons of heavier ions for therapy, the presentation will concentrate on two aspects of the therapy with ions heavier than protons: technical equipment and choice of ion. As major components of an IBT facility, accelerator and gantry issues will dominate the part on equipment. Biophysical, medical, and economical considerations will be discussed in the part featuring the choice of the proper ion.

Slides THXC2 [10.744 MB]

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THYC2

Recent Trends in Beam Size Measurements using the Spatial Coherence of Visible Synchrotron Radiation

synchrotron, optics, photon, operation

3662

T.M. Mitsuhashi
KEK, Ibaraki, Japan

The optical method of measuring the transverse beam profile and size using visible synchrotron radiation (SR) began with simple imaging systems. The resolution was limited by both the diffraction and the wavefront error making it difficult to resolve beam sizes less than 50 μm. Instead of imaging, a method for measuring the beam profile and size using the spatial coherence was introduced. The method is based on Van Cittert-Zernike’s theorem, and can resolve 4-5 μm beam sizes with an error of only 0.5 μm. In this presentation, the principle of the measurement, the SR interferometer design, and some resent measurement results are reviewed. The incoherent field depth effect for the horizontal beam size measurement is also described with some results. Design study calculations for the SR interferometer at the LHC will be presented.

Slides THYC2 [2.629 MB]

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THPF044

Status of the J-PARC 3 GeV RCS

operation, injection, linac, vacuum

3798

M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan

Beam injection energy of the RCS in J-PARC was increased from 181 MeV to 400 MeV, and user operation with beam energy of 300 kW for both the MLF and the MR was performed with high availability from February to Jun in 2014. Beam losses during beam injection period was decreased by reduction of space charge effect due to increase of beam injection energy. Since an ion source and an RFQ of the LINAC are replaced to realize 1 MW beam power at the RCS in summer maintenance period, injection beam peak current was increased from 30 mA to 50 mA. User operation was restarted from November with beam power of 300 kW. The beam power for user operation will be gradually increased after getting radiation safety permission from government. High intensity beam study was also performed and it was successfully to accelerate beam of 770 kW equivalent without beam loss except foil scattering loss. In this beam study it was cleared issues to realize 1MW operation in the RCS. Status of user operation and issues to realize high power operation in the RCS are presented.

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THPF124

Energy Deposition and Radiological Studies for the LBNF Hadron Absorber

target, hadron, operation, shielding

4007

I.L. Rakhno, N.V. Mokhov, I.S. Tropin
Fermilab, Batavia, Illinois, USA
Y.I. Eidelman
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: This work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Results of optimization energy deposition and radiological studies performed for the LBNF hadron absorber system are presented. The model of the LBNF complex starting from the beam extraction from the Main Injector and primary beam line through the pion-production target, focusing horns, target chase, decay channel, hadron absorber system with its beam instrumentation and civil infrastructure – all with corresponding radiation shielding – was developed using the ROOT-based geometry option in the MARS15 code. Both normal operation and accidental conditions were studied for the 120-GeV proton beam at 2.4 MW. Various design options were considered, in particular: (i) the absorber mask material and shape; (ii) the beam spoiler material and size; (iii) sculpted core aluminum blocks; (iv) various configurations of the core and its shielding and (v) numerous modifications of the overall system configurations. These helped find the optimal design solution for the absorber lifetime and radiation levels in the service building and environment to be within the design goals with an adequate safety margin.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF124

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THPF129

The MICE Demonstration of Lonization Cooling

lattice, emittance, acceleration, cavity

4023

J. Pasternak, C. Hunt, J.-B. Lagrange, K.R. Long
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V. Blackmore
Imperial College of Science and Technology, London, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy
R. Preece, J.S. Tarrant
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Fermilab, Batavia, Illinois, USA

Funding: SFTC, DOE, NSF, INFN, CHIPP and more
Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions at energies of up to several TeV at the Muon Collider. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam passes through a material (the absorber) in which it loses energy. The energy lost is then replaced using RF cavities. The combined effect of energy loss and re-acceleration is to reduce the transverse emittance of the beam (transverse cooling). A major revision of the scope of the project was carried out over the summer of 2014. The revised project plan, which has received the formal endorsement of the international MICE Project Board and the international MICE Funding Agency Committee, will deliver a demonstration of ionization cooling by September 2017. In the revised configuration a central lithium-hydride absorber provides the cooling effect. The magnetic lattice is provided by the two superconducting focus coils and acceleration is provided by two 201 MHz single-cavity modules. The phase space of the muons entering and leaving the cooling cell will be measured by two solenoidal spectrometers. All the superconducting magnets for the ionization cooling demonstration are available at the Rutherford Appleton Laboratory and the first single-cavity prototype is under test in the MuCool Test Area at Fermilab. The design of the cooling demonstration experiment will be described together with a summary of the performance of each of its components. The cooling performance of the revised configuration will also be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF129

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THPF134

Magnet Design and Synchrotron Damping Considerations for a 100 TeV Hadron Collider

collider, dipole, synchrotron, luminosity

4034

P.M. McIntyre, S. Assadi, J. Gerity, T.L. Mann, A. Sattarov
Texas A&M University, College Station, Texas, USA
D. Chavez
DCI-UG, León, Mexico
N. Pogue
PSI, Villigen, Villigen, Switzerland
M. Tomsic
Hypertech Research, Inc., Columbus, USA

A conceptual design is presented for a 100 TeV hadron collider based upon a 4.5 T NbTi cable-in-conduit dipole technology. It incorporates a side radiation channel to extract synchrotron radiation from the beam channel so that it does not produce limitations from heating on a beam liner or gas load limits on collider performance. Synchrotron damping can be used to support ‘bottom-up’ stacking to sustain maximum luminosity in the collisions.

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FRXC2

The High Luminosity LHC Project

luminosity, operation, dipole, experiment

4096

O.S. Brüning
CERN, Geneva, Switzerland

This presentation reviews the status of the high luminosity LHC project, and highlights the main challenges from the technology and beam physics point of view. It will mention the outcome of the 2015 Cost and Schedule review for the HL-LHC project and summarizes the status of the high field quadrupole and crab cavity development.

Slides FRXC2 [7.951 MB]

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