IPAC2015 - List of Keywords (detector)

Paper	Title	Other Keywords	Page
MOPWA009	Channeling Radiation Experiment at Fermilab ASTA	electron, photon, brilliance, experiment	95
	D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Edstrom, P. Piot, T. Sen Fermilab, Batavia, Illinois, USA W.D. Rush KU, Lawrence, Kansas, USA
	Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA009
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MOPWA049	Simulation of Crab Waist Collisions in DAΦNE with KLOE-2 Interaction Region	simulation, luminosity, electron, betatron	229
	M. Zobov, A. Drago, A. Gallo, C. Milardi INFN/LNF, Frascati (Roma), Italy D.N. Shatilov BINP SB RAS, Novosibirsk, Russia A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404. After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentially achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e^- ring working point was implemented and resulted in a significant performance increase.
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MOPJE037	Study and Comparison of Mode Damping Strategies for the UA9 Cherenkov Detector Tank	damping, cavity, vacuum, resonance	366
	A. Danisi, F. Caspers, R. Losito, A. Masi, B. Salvant, C. Vollinger CERN, Geneva, Switzerland T. Demma, P. Lepercq LAL, Orsay, France
	In the framework of the UA9 experiment, the Cherenkov detector is useful to measure the amount of particles deflected by a bent crystal, proving the crystal collimation principle. The tank used to host this device is taken as a case study for an in-depth analysis of different damping strategies for electromagnetic modes which otherwise would give rise to important beam-coupling impedance contributions. Such strategies involve the use of ferrite, damping resistors and a mode-coupler, a solution which intercepts the modes inside the cavity but damps the related power outside the vacuum tank (potentially avoiding heating). Such solutions are discussed through experimental measurements and the relative quality factor is taken as a figure of merit.
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MOPJE064	Beam Impedance Optimization of the TOTEM Roman Pots	impedance, simulation, cavity, vacuum	452
	N. Minafra CERN, Geneva, Switzerland
	The TOTEM experiment has been designed to measure the total proton-proton cross section and to study elastic and diffractive scattering at the LHC energy. The measurement requires detecting protons at distances as small as 1 mm from the beam center: TOTEM uses Roman Pots (RP), special beam pipe insertions, to move silicon detectors close to the beams to detect particles very near the beam axis. In the first period of running of the LHC no problems were detected with retracted Roman Pots and during insertions in special runs; however, during close insertions to highest intensity beam, impedance heating has been observed. After the LS1 the LHC beam current will increase and the equipment that can interact with the beam needed to be optimized. A new RP, optimized to minimize the beam coupling, has been designed with the help of CST Particle Studio; a prototype has been used to test the simulation results in the laboratory with wire and probe measurements. Furthermore, in both the old and the new RPs, new ferrites have been installed. The new ferrite material has a higher Curie temperature than the one used before LS1 and a thermal treatment at 1000°C has been applied to reduce the out-gassing.
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MOPJE070	Reduction of Electron Cloud in Particle Accelerator Beampipes Studied by RF Multipacting	electron, injection, vacuum, network	472
	R. Leber, F. Caspers, P. Costa Pinto, M. Taborelli CERN, Geneva, Switzerland
	For a given beam structure, chamber geometry and magnetic field configuration, the electron cloud (EC) intensity depends on the Secondary Electron Yield (SEY) of the beam pipe. The reduction of the EC density as a function of machine operation time (scrubbing) is attributed to the growth of a low SEY carbon film induced by electron bombardment. In this paper, we study the time evolution of the conditioning of stainless steel beam pipes in a laboratory setup. The EC or multipacting is induced by Radio-Frequency (RF) fields in a coaxial resonator under vacuum. Strip detectors are used to monitor the current of the EC. Induced pressure rise is simultaneously detected. The multipacting intensity shows a linear dependence on the positive DC bias voltage up to 1000 V, applied to the central electrode. An accelerated conditioning is observed for the applied bias voltage. The SEY of samples exposed to the EC is measured and the surface composition is monitored by X-ray Photoelectron Spectroscopy. The measured SEY, surface composition and multipacting behaviour are well correlated. The injection of acetylene and dodecane during multipacting proved to be ineffective in the conditioning.
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MOPJE071	New Electron Cloud Detectors for the CERN Proton Synchrotron	photon, electron, proton, extraction	476
	C. Yin Vallgren, P. Chiggiato, S.S. Gilardoni, H. Neupert, M. Taborelli CERN, Geneva, Switzerland
	Electron cloud (EC) has already been observed during normal operation of the PS using classical shielded button pick-up detectors in drift sections. In the context of the LHC Injector Upgrade (LIU project), similar measurements are also needed for the combined function magnets of the machine, where the access to the vacuum chamber is strongly limited by the presence of the yoke. Two new electron cloud detectors have been studied, developed, and installed during the Long Shutdown (LS1) in one of such magnets. The first is based on current measurement by using a shielded button-type pick-up with a special geometry to reach the bottom surface of the vacuum pipe embedded in the magnet. The second one relies on a newly developed measurement method based on detection of the photons, which are emitted by cathodoluminescence from the electron cloud impinging on the vacuum chamber walls. Part of the emitted photons is collected through a quartz window by a Micro-Channel Plate Photomultiplier Tube (MCP-PMT). First results obtained during machine development runs show the feasibility of the photon detection scheme. The results are discussed and compared with pick-up measurements.
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MOPJE082	Analytical Approach to the Beam-Beam Interaction with the Hourglass Effect	luminosity, coupling, collider, framework	510
	M.P. Crouch, R.B. Appleby UMAN, Manchester, United Kingdom B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: STFC HL-LHC The HL-LHC upgrade will allow higher luminosities to be reached in the LHC. To achieve higher luminosities the β-function at the IP is decreased, which in turn will result in the hourglass effect becoming more prominent as the transverse bunch sizes become comparable to the length of the bunch. This effect reduces the luminosity since not all particles in the bunch will collide at the minimum IP. The standard derivation of the electric and magnetic fields of the beam-beam interaction is that undertaken by Bassetti and Erskine. The derivation by Bassetti Erskine does not include a coupling between bunch planes. When the transverse bunch sizes are comparable to the length of the bunch the magnitude of the transverse kick will be dependent on the longitudinal position. Currently only numerical methods are available to evaluate this effect. Here a theoretical framework is outlined that provides an analytical approach to derive the electric field for the beam-beam interaction with a coupling between the transverse and longitudinal planes.
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MOPMA003	Reconstruction of Electron Bunch Motion During CSR Bursts using Synchronised Diagnostics	electron, synchrotron, radiation, 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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MOPMA005	Non-invasive Beam Profile Monitoring	vacuum, operation, ion, proton	537
	C.P. Welsch, T. Cybulski, A. Jeff, V. Tzoganis, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom T. Cybulski, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom A. Jeff CERN, Geneva, Switzerland V. Tzoganis RIKEN, Saitama, Japan
	Funding: Work supported by the Helmholtz Association under contract VH-NG-328, the EU under contracts 215080 and 289485, as well as the STFC Cockcroft core grant No. ST/G008248/1. State-of-the-art high energy and high intensity accelerators require new approaches to transverse beam profile monitoring as many established techniques will no longer work due to the high power stored in the beam. In addition, many accelerator applications such as ion beam cancer therapy or material irradiation would benefit significantly from the availability of non-invasive beam profile monitors. Research in the QUASAR Group has focused on this area over the past 5 years. Two different approaches were successfully developed: Firstly, a supersonic gas jet-based monitor was designed and commissioned. It enables the detection of the 2-dimensional transverse beam profile of essentially any charged particle beam with negligible disturbance of the primary beam and accelerator vacuum. Secondly, a monitor based on the Silicon strip VELO detector, originally developed for the LHCb experiment, was tested as an online beam monitor at the Clatterbridge Cancer Center in the UK. The design of both monitors is presented in this contribution. Results from measurements are discussed and complemented by numerical studies into the performance limits of either technique.
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MOPMA031	Simulations of Diamond Detectors with Schottky Contacts	electron, simulation, photon, scattering	617
	G.I. Bell, J.R. Cary, D.A. Dimitrov, D. Meiser, D.N. Smithe, C.D. Zhou Tech-X, Boulder, Colorado, USA M. Gaowei, E.M. Muller SBU, Stony Brook, New York, USA J. Smedley BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences, grant numbers DE-SC0006246 and DE-SC0007577. We present simulations of semiconductor devices using the code VSim (formerly Vorpal). The 3D simulations involve the movement and scattering of electrons and holes in the semiconductor, voltages which may be applied to external contacts, and self-consistent electrostatic fields inside the device. Particles may experience a Schottky barrier when moving between the semiconductor and a metal contact. Example devices include MOSFETs as well as a diamond X-ray detector. Our code VSim includes scattering models for GaAs and diamond, and runs in parallel on thousands of processors. We compare our simulation results with experimental results from a prototype diamond X-ray detector.
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MOPMA055	MuSim, a Graphical User Interface for Multiple Simulation Programs	simulation, interface, storage-ring, target	678
	T.J. Roberts Muons, Inc, Illinois, USA P.L. Gueye Hampton University, Hampton, Virginia, USA
	MuSim is a new user-friendly program designed to interface to many different particle simulation codes, regardless of their data formats or geometry descriptions. It presents the user with a compelling graphical user interface that includes a flexible 3-D view of the simulated world plus powerful editing and drag-and-drop capabilities. All aspects of the design can be parametrized so that parameter scans and optimizations are easy. It is simple to create plots and display events in the 3-D viewer (with a slider to vary the transparency of solids), allowing for an effortless comparison of different simulation codes. Simulation codes: G4beamline, MAD-X, and MCNP; more coming. Many accelerator design tools and beam optics codes were written long ago, with primitive user interfaces by today’s standards. MuSim is specifically designed to make it easy to interface to such codes, providing a common user experience for all, and permitting the construction and exploration of models with very little overhead. For today’s technology-driven students, graphical interfaces meet their expectations far better than text-based tools, and education in accelerator physics is one of our primary goals.
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MOPHA007	Modeling/Measurement Comparison of Signal Collection in Diamond Sensors in Extreme Conditions	electron, space-charge, simulation, scattering	787
	V. Kubytskyi, P. Bambade, S. Liu LAL, Orsay, France
	Here we present a study of charge collection dynamics in a Diamond Sensor (DS) subjected to intensities from 1 to 10⁸ Minimum Ionizing Particles (MIP). We developed a model based on the numerical solution of the 1D drift-diffusion equations, using the Scharfetter-Gummel discretization scheme. Inhomogeneity of the space-charge distribution together with the externally applied electric field are taken into account by analytically solving the Poisson equation at each time step. We identified two regimes of charge collection. The first corresponds to 1-10⁵ MIPs, in this case the externally applied electric field is negligibly perturbed by space-charge effects during the separation of the electron/hole clouds. The second corresponds to intensities larger than 10⁷ MIPs, where the space-charge effects significantly slow down the charge collection due to large concentrations of electron/hole pairs in the DS volume. The results of our modeling are in qualitative agreement with the experimental data acquired at the PHoto-Injector electron beam facility at LAL. Our model allows optimizing DS parameters to achieve desired charge collection times for different beam intensities.
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MOPHA009	Single-Shot Electro-Optic Sampling Combined With Photonic Time-Stretch: Detailed Results at SOLEIL	laser, synchrotron, storage-ring, real-time	795
	C. Szwaj, C. Evain, E. Roussel PhLAM/CERLA, Villeneuve d'Ascq, France S. Bielawski PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France J.B. Brubach, L. Cassinari, M.-E. Couprie, M. Labat, L. Manceron, J.P. Ricaud, P. Roy, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France M. Le Parquier CERLA, Villeneuve d'Ascq, France
	Funding: ANR (DYNACO project), FEDER, CEMPI LABEX. Single-shot recording of pulses is possible with high repetition rates (more than 80 MHz), as was demonstrated in the framework of a PhLAM-SOLEIL collaboration * *. This can be achieved by a relatively simple upgrade of existing setups based on spectral encoding. The strategy consists to encode the sub-picosecond information into the time domain, but at a slower scale (nanoseconds), using dispersion in a long optical fiber. Then the information is recorded by a photodiode connected to an oscilloscope. In this poster, we present guidelines for the practical realization of the electro-optical setup, as well as a performance analysis. In particular, we analyze the temporal resolution and compare it to the classical electro-optical sampling setup. E. Roussel et al., Proceedings of IPAC2014, THOBA01. ** E. Roussel et al., arXiv:1410.7048
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MOPHA023	Observation of Coherent Pulses in the Sub-THz Range at DELTA	electron, radiation, 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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MOPHA026	Present and Future Optical-to-Microwave Synchronization Systems at REGAE Facility for Electron Diffraction and Plasma Acceleration Experiments	laser, electron, timing, plasma	833
	M. Titberidze, F.J. Grüner, A.R. Maier, B. Zeitler CFEL, Hamburg, Germany S.W. Epp MPSD, Hamburg, Germany M. Felber, K. Flöttmann, T. Lamb, U. Mavrič, J.M. Müller, H. Schlarb, C. Sydlo DESY, Hamburg, Germany F.J. Grüner, A.R. Maier, M. Titberidze Uni HH, Hamburg, Germany E. Janas Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Relativistic Electron Gun for Atomic Explorations (REGAE) is a Radio Frequency (RF) driven linear accelerator. It uses frequency tripled short photon pulses (~ 35 fs) from the Titanium Sapphire (Ti:Sa.) Laser system in order to generate electron bunches from the photo-cathode. The electron bunches are accelerated up to ~ 5 MeV kinetic energy and compressed down to sub-10 fs using the so called ballistic bunching technique. REGAE currently is used for electron diffraction experiments (by Prof. R.J.D. Miller's Group). In near future within the collaboration of Laboratory for Laser- and beam-driven plasma Acceleration (LAOLA), REGAE will also be employed to externally inject electron bunches into laser driven linear plasma waves. Both experiments require very precise synchronization (sub-50 fs) of the photo-injector laser and RF reference. In this paper we present experimental results of the current and new optical to microwave synchronization systems in comparison. We also address some of the issues related to the current system and give an upper limit in terms of its long-term performance.
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MOPHA027	Transverse Emittance Measurement at REGAE	emittance, electron, background, solenoid	837
	M. Hachmann, K. Flöttmann DESY, Hamburg, Germany
	The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.
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MOPHA037	Visible Light Diagnostics at the ANKA Storage Ring	synchrotron, photon, diagnostics, radiation	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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MOPHA040	First Results of Energy Measurements with a Compact Compton Backscattering Setup at ANKA	laser, electron, photon, storage-ring	876
	C. Chang, E. Bründermann, E. Hertle, N. Hiller, E. Huttel, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann KIT, Karlsruhe, Germany H.-W. Hübers, H. Richter DLR, Berlin, Germany
	Funding: This work is funded by the European Union under contract PITN-GA-2011-289191 An electron energy measurement setup based on the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam, has been proposed and developed for operation at the ANKA storage ring of the Karlsruhe Institute of Technology (KIT). In contrast to conventional methods based on head-on collisions, the setup at ANKA is, for the first time, realized in a transverse configuration where the laser beam hits the electron beam at an angle of ~90°. This makes it possible to achieve a relatively low-cost and very compact setup since it only requires a small side-port instead of a straight section. This development could benefit storage rings with restricted space or where no straight sections are available, for example due to interferences with existing beamlines. The setup and the first measurement results are presented in the paper.
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MOPHA043	Properties of Transition- and Synchrotron Radiation at FLUTE	radiation, synchrotron, synchrotron-radiation, electron	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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MOPHA048	Beam Optimization of the DAΦNE Beam Test Facility	diagnostics, linac, software, electron	901
	L.G. Foggetta, B. Buonomo INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The DAΦNE Beam Test Facility delivers electron and positron beam with a wide spread of parameters in charge, energy, transverse dimensions and time width. Thanks to the recent improvements of the diagnostics, all the beam parameters have been measured and optimized. In particular we report here some results on beam transverse size, divergence, and position stability for different energy and intensity configurations. After the upgrade of the electronic gun of the DAΦNE LINAC, the pulse time width and charge distribution have been also characterized.
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MOPHA049	Evolution of Diagnostics and Services of the DAΦNE Beam Test Facility	vacuum, linac, controls, diagnostics	904
	L.G. Foggetta, B. Buonomo INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The DAΦNE Beam Test Facility (BTF) is operational in Frascati since 2003. In the last years the beam diagnostics tools have been completely renewed and the services for users have been largely improved. We describe here the new transverse beam diagnostics based on new GEM TPC detectors and Timepix/FitPix, the new BTF network layout, the renewed DAQ system including the BCM detectors, the data caching system based on MEMCached and the integration of the new sub-systems in the new data-logging. All other services, such as the environmental monitoring system, vacuum system, payload remote handling, and gas distribution have been also improved.
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MOPHA051	Scintillating Fibers used as Profile Monitors for the CNAO HEBT Lines	proton, ion, extraction, vacuum	910
	E. Rojatti UniPV, Pavia, Italy J. Bosser, M. Haguenauer, P. Poilleux CERN, Geneva, Switzerland J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, M. Pullia, C. Viviani CNAO Foundation, Milan, Italy M. Caldara University of Bergamo, Bergamo, Italy
	The CNAO (Centro Nazionale di Adroterapia Oncologica) Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions. Several beam monitors exploiting the scintillation process have been designed to check the beam quality in the extraction lines, in order to guarantee patients safety. The SFH (Scintillating Fibers Harp), the QPM (Qualification Profile Monitor), and the SFP (Scintillating Fibers plus Photodiodes) are made up by two orthogonal scintillating fibers harps with not dead area for the horizontal and the vertical beam profiles measurement. The QPM and the SFH are both installed on the beam line and they use a CCD camera for the signal acquisition. The SFP is a SFH upgrade project aimed to replace the camera with two Photodiodes arrays coupled to the fibers in vacuum. The WD (Watch Dog) detector, not already installed, has been designed to check the beam position through the intensity of the beam tails. It uses two couples of scintillating fibers displaced transversally to the beam direction, coupled to four APDs (Avalanche Photodiodes). This work describes the beam detectors, their achieved performances and the most recent beam measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA051
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MOPHA053	Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity	cavity, linac, coupling, radiation	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, radiation, 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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MOPTY011	Operation Experience of p-Carbon Polarimeter in RHIC	target, polarization, vacuum, operation	956
	H. Huang, E.C. Aschenauer, G. Atoian, A. Bazilevsky, O. Eyser, D. Kalinkin, J. Kewisch, Y. Makdisi, S. Nemesure, A. Poblaguev, W.B. Schmidke, D. Smirnov, D. Steski, K. Yip, A. Zelenski BNL, Upton, Long Island, New York, USA I.G. Alekseev, D. Svirida ITEP, Moscow, Russia
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The spin physics program in Relativistic Heavy Ion Collider (RHIC) requires fast polarimeter to monitor the polarization evolution on the ramp and during stores. Over past decade, the polarimeter has evolved greatly to improve its performance. These include dual chamber design, monitoring camera, Si detector selection (and orientation), target quality control, and target frame modification. The preamp boards have been modified to deal with the high rate problem, too. The ultra thin carbon target lifetime is a concern. Simulations have been carried out on the target interaction with beam. Modification has also been done on the frame design. Extra caution has been put on RF shielding to deal with the pickup noises from the nearby stochastic cooling kickers. This paper summarizes the recent operation performance of this delicate device.
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MOPTY016	Study of Diamond Detector Application at the Front End of a High Intensity Hadron Accelerator	radiation, 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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MOPTY041	Prototype Results with a Complete Beam Loss Monitor System Optimized for Synchrotron Light Sources	electron, injection, electronics, impedance	1019
	P. Leban I-Tech, Solkan, Slovenia K.B. Scheidt ESRF, Grenoble, France
	Beam loss monitors in synchrotron light sources are finding an increasing utility in particular with the trend of numerous light sources pushing to lower emittances and thus higher intra-beam scattering, while operating in top-up injection modes and employing in-vacuum undulators in their rings. The development of an optimized electron BeamLoss Monitor aims at fulfilling, in one single system, all possible functionalities and applications like both the measurement of fast-time-resolved losses at injection and the possibility of ultra-sensitive detection of low & slow electron loss level variations. This optimized beam loss monitor system comprises both the acquisition electronics and up to four sensor head per unit. The sensor heads themselves, that can be configured for different sizes or volumes, are based on the detection of the electromagnetic shower resulting from an electron loss through the use of either Cherenkov radiator or gamma scintillator and a photomultiplier tube, all assembled in a single compact housing ready for installation.
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MOPTY047	ESS Cold LINAC BLM Locations Determination	simulation, linac, quadrupole, proton	1039
	M. Jarosz, A. Jansson, J.C. Kazantzidis, T.J. Shea, L. Tchelidze ESS, Lund, Sweden
	Funding: This project (oPAC) is funded by the European Union under contract PITN-GA-2011-289485. The linear accelerator of ESS will produce a 5 MW proton beam. Beam of this power must be strictly monitored by a specialized Beam Loss Monitoring (BLM) System to detect any abnormal losses and to ensure that operational losses do not lead to excessive activation. A long series of beam loss simulations was performed using MARS Monte Carlo code system in order to optimize the number and setting mounting locations of the detectors for best coverage, distinguishability and sensitivity. Simulations anticipated multiple possible beam loss scenarios resulting in different loss patterns. The results of energy deposition in air in the linac tunnel in multiple locations were analysed in several different ways. Incorporated methods varied from simple brute force approach to more sophisticated singular value decomposition based algorithms, all resulting in detector layout proposals. Locations selected for BLMs were evaluated for all methods.
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MOPTY055	Beam Loss Monitoring for Run 2 of the LHC	monitoring, injection, database, beam-losses	1057
	M.K. Kalliokoski, B. Auchmann, B. Dehning, F.S. Domingues Sousa, E. Effinger, J. Emery, V. Grishin, E.B. Holzer, S. Jackson, B. Kolad, E. Nebot Del Busto, O. Picha, C. Roderick, M. Sapinski, M. Sobieszek, C. Zamantzas CERN, Geneva, Switzerland
	The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss all the changes made to the BLM system, with the reasoning behind them.
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MOPTY057	Feasibility Study of Monitoring the Population of the CERN-LHC Abort Gap with Diamond Based Particle Detectors	beam-losses, monitoring, kicker, simulation	1065
	O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann CERN, Geneva, Switzerland
	At the end of a physics fill and in case of a failure, the LHC beams must be extracted and transferred through a 750m long line to the beam dump block. During the rise of the extraction kickers to their full strength a particle-free abort gap, with a length of 3 us in the LHC filling pattern, is required to prevent beam losses that could lead to substantial quenching of magnets, with a risk of damage. Therefore the particle population in the abort gap, which is mainly due to un-bunched beam, is monitored. Above a certain threshold an active cleaning by excitation of betatron oscillations with the transverse feedback system is initiated. This paper describes a novel method of monitoring the abort gap population using diamond particle detectors for detecting the interactions of beam in the abort gap with neon gas, injected in the beam pipe. Two different layouts of the system and the expected interaction and detection rates are discussed.
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MOPTY058	Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam	electron, experiment, radiation, 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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MOPTY080	A Multi-band Single Shot Spectrometer for Observation of mm-Wave Bursts at Diamond Light Source	storage-ring, synchrotron, radiation, 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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MOPWI003	Laserwire Emittance Scanner at CERN Linac 4	laser, linac, emittance, ion	1146
	K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca CERN, Geneva, Switzerland A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.
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MOPWI010	Design and Development of a Beam Stablity Mechanical Motion System Diagnostic for the APS MBA Upgrade	vacuum, insertion, insertion-device, ground-motion	1164
	R.M. Lill, G. Decker, N. Sereno, B.X. Yang ANL, Argonne, Ilinois, USA
	Funding: Results shown in this report result from work performed at Argonne National Laboratory operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357. The Advanced Photon Source (APS) is currently in the conceptual design phase for the MBA lattice upgrade. In order to achieve long-term beam stability goals, a Mechanical Motion System (MMS) has been designed to monitor critical in-tunnel beam position monitoring devices. The mechanical motion generated from changes in chamber cooling water temperature, tunnel air temperature, beam current and undulator gap positon causes erroneous changes in beam position measurements causing drift in the X-ray beam position. The MMS has been prototyped and presently provides critical information on the vacuum chamber and BPM support systems. We report on first results of the prototype system installed in the APS storage ring.
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MOPWI017	Beam Extinction Monitoring in the Mu2e Experiment	proton, target, experiment, shielding	1185
	E. Prebys, A. Gaponenko, P.H. Kasper Fermilab, Batavia, Illinois, USA L.M. Bartoszek Bartoszek Engineering, Aurora, Illinois, USA
	Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359. The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10^-10 fractional level. The verification of this level of extinction is very challenging. The proposed technique uses a special purpose spectrometer which will observe particles scattered from the production target of the experiment. The acceptance will be limited such that there will be no saturation effects from the in-time beam. The precise level and profile of the out-of-time beam can then be built up statistically, by integrating over many bunches.
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MOPWI029	Electron Bombardment of ZnTe EO Bunch Charge Detector for Signal Lifetime Studies in Radiation Environment	electron, lattice, laser, radiation	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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MOPWI036	Investigation of Continuous Scan Methods for Rapid Data Acquisition	data-acquisition, software, experiment, hardware	1243
	C.L. Li East China University of Science and Technology, Shanghai, People's Republic of China A.M. Kiss SLAC, Menlo Park, California, USA W.J. Zhang University of Saskatchewan, Saskatoon, Canada
	It is common practice to perform spatially resolved X ray data acquisition by automatically moving components to discrete locations and then measuring beam intensity with the system at rest. While effective, scanning in this manner can be time consuming, with motors needing to accelerate, move and decelerate at each location before recording data. Information between data points may be missed unless fine grid scans are performed, which accounts for a further increase of scan time. Recent advances in commercial hardware and software enables a continuous scan capability for a wide range of applications, which saves the start and end of step motors. To compare scanning performance, both step and continuous scan modes were examined using the SPEC command language with both commercial and in-house hardware. The advantages and limitations of each are discussed.
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MOPWI052	Responsivity Study of Diamond X-ray Monitors with nUNCD Contact	photon, synchrotron, plasma, database	1273
	M. Gaowei, J. Smedley BNL, Upton, Long Island, New York, USA E.M. Muller, T. Zhou SBU, Stony Brook, New York, USA A.V. Sumant Argonne National Laboratory, Center for Nanoscale Materials, Argonne, USA
	Nitrogen doped ultrananocrystalline diamond (nUNCD) grown on the surface of a CVD single crystal diamond is tested at various beamlines covering an x-ray photon energy range of 200eV to 28 keV. The nUNCD has much lower x-ray absorption than metal contacts and is designed to improve the performance of our device. The responsivity of nUNCD diamond x-ray detector is compared with the conventional platinum coated diamond x-ray beam position monitor and the results are presented in this paper.
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TUAC3	Optimization of Beam Loss Monitor Network for Fault Modes	cavity, network, simulation, lattice	1356
	Z. Liu, Z.Q. He, S.M. Lidia, D. Liu, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Beam Loss Monitoring (BLM) System is an essential part to protect accelerator from machine faults. Compared with the empirical or uniform BLM arrangement in most accelerators, our new optimization approach proposes a “minimum spatial distribution” for BLM network. In this distribution, BLMs shall be placed at a small set of “critical positions” that can detect all failure / FPS trigger-able events of each fault mode. In additional, to implement a more advanced function of fault diagnosis, BLM should also be placed at “discrimination points” for fault-induced loss pattern recognition. With examples of FRIB failure event simulations, the author demonstrates the proof of concept to locate these “critical positions” and “discrimination points” for the minimum spatial distribution of BLMs.
	Slides TUAC3 [2.341 MB]
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TUPWA016	Modeling of beam losses at ESRF	vacuum, scattering, simulation, electron	1430
	R. Versteegen, P. Berkvens, N. Carmignani, J. Chavanne, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, K.B. Scheidt, S.M. White ESRF, Grenoble, France
	As the ESRF enters the second phase of its upgrade towards ultra low emittance, the knowledge of the beam loss pattern around the storage ring is needed for radiation safety calculations and for the new machine design optimization. A model has been developed to simulate the Touschek scattering and the scattering of electrons on residual gas nuclei in view of producing a detailed loss map of the machine. Results of simulation for the ESRF are presented and compared with real beam measurements.
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TUPWA066	Development of a High Average Power Laser for High Brightness X-ray Source and Imaging at cERL	laser, cavity, electron, photon	1579
	A. Kosuge, T. Akagi, S. Araki, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan R. Hajima, M. Mori, T. Shizuma JAEA, Ibaraki-ken, Japan R. Nagai JAEA/ERL, Ibaraki, Japan
	Funding: This study is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT, Japan. High brightness X-rays via laser-Compton scattering (LCS) of laser photons stored in an optical cavity by a relativistic electron beam is useful for many scientific and industrial applications such as X-ray imaging. The construction of compact Energy Recovery Linac (cERL) is now in progress at KEK to generate low-emittance and high-current electron beams. In order to demonstrate the generation of high brightness LCS X-rays, it is necessary to develop a high average power injection laser and an optical four-mirror ring cavity with two concave mirrors which is used to produce a small spot laser beam inside the cavity. In this presentation, we will show the result of the development of the high average laser system, the LCS X-rays generation, and the X-ray imaging.
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TUPJE012	Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments	laser, synchrotron, experiment, timing	1638
	J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou IHEP, Beijing, People's Republic of China
	Funding: This work is supported by the NSFC under grant No.11305186 R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.
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TUPJE055	The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State	electron, cathode, brightness, vacuum	1748
	L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.E. Scheibler, A.S. Terekhov ISP, Novosibirsk, Russia
	The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and is increased significantly if the mean values of these quantities are reduced. To address this, ASTeC constructed a Transverse Energy Spread Spectrometer (TESS)* – an experimental facility designed to measure these transverse and longitudinal energy distributions which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. We present measurements showing evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Photocathodes were activated to negative electron affinity in our photocathode preparation facility (PPF)** with quantum efficiency around 10.5%. They were then transferred to TESS under XHV conditions, and progressively degraded through controlled exposure to oxygen. Data has been collected under photocathode illumination at 635 nm, and demonstrates a constant relationship between energy distribution and the level of electron affinity. * Proc. FEL ’13, TUPPS033, 290-293 ** Proc. IPAC '10, TUPE095, 2347-2349, Proc. IPAC ’11, THPC129, 3185-3187
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TUPMA008	Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance	impedance, space-charge, simulation, radiation	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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TUPMA017	Pulsed-wire Measurements for Insertion Devices	undulator, electron, FEL, laser	1869
	A. D'Audney, S. Biedron, S.V. Milton, S.A. Stellingwerff CSU, Fort Collins, Colorado, USA
	The performance of a Free Electron Laser (FELs) depends in part on the integrity of the magnetic field in the undulator. The magnetic field on the axis of the undulator is transverse and sinusoidally varying due to the periodic sequence of dipoles. The ideal trajectory of a relativistic electron bunch, inserted along the axis, is sinusoidal in the plane of oscillation. Phase errors are produced when the path of the electron is not the ideal sinusoidal trajectory, due to imperfections in the magnetic field. The result of such phase errors is a reduction of laser gain impacting overall FEL performance. A pulsed-wire method can be used to determine the profile of the magnetic field. This is achieved by sending a square current pulse through the wire, which will induce an interaction with the magnetic field. Measurement of the displacement in the wire over time using a motion detector yields the first or second integrals of the magnetic field. Dispersion in the wire can be corrected using algorithms resulting in higher accuracy. Once the fields are known, magnetic shims are placed where any corrections are needed.
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TUPMA036	First e-/Photon Commissioning Results for the GlueX Experiment/Hall D at CEBAF	photon, radiation, 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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TUPTY004	Tracking Simulation for Beam Loss Studies with Application to FCC	simulation, lattice, scattering, collider	2004
	M. Boscolo INFN/LNF, Frascati (Roma), Italy H. Burkhardt CERN, Geneva, Switzerland
	We present an implementation of a tracking simulation tool used to evaluate the main particle loss effects for Flavor Factories with the aim of applying these studies also to FCC. We describe the interface of the Monte Carlo tracking code with MAD-X, showing first simulations of the Touschek effect for the FCC-ee at the Z. We plan to use this approach also for multi-turn simulations of particles scattered by radiative Bhabha, beam-gas and eventually Beamstrahlung effects.
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TUPTY011	A Preliminary Design of the CEPC Interaction Region	interaction-region, dynamic-aperture, quadrupole, luminosity	2019
	Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Geng, D. Wang, Y.S. Zhu IHEP, Beijing, People's Republic of China
	CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×10³⁴/cm²/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.
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TUPTY016	Study of Background and MDI Design for CEPC	background, scattering, photon, simulation	2028
	Y. Yue, Q. Qin IHEP, Beijing, People's Republic of China
	CEPC is a project designed to obtain a large number of Higgs events by keeping e⁺e⁻ collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 10³⁴ cm^-2 s^-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.
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TUPTY017	Ion Polarization Control in the MPD and SPD Detectors of the NICA Collider	polarization, solenoid, collider, proton	2031
	A.D. Kovalenko, A.V. Butenko, V.D. Kekelidze, V.A. Mikhaylov JINR, Dubna, Moscow Region, Russia Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	Two solenoid Siberian snakes are placed in the opposite collider’s straight sections are used to control deuteron’s and proton’s polarization in the NICA collider. Solenoid snakes substantially reconstruct beam’s orbital motion. The change of the polarization direction in the vertical plane of MPD and SPD detectors occurs due to insertion of polarization control (PC) solenoids in the magnetic lattice of the collider. The solenoids rotating particle’s spin by small angels practically do not influence on the beam’s orbital motion parameters. The dynamic of the polarization vector as function of the orbit length for cases of longitudinal and vertical polarization in the MPD and SPD detectors are presented.
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TUPTY031	Tools for Flexible Optimisation of IR Designs with Application to FCC	radiation, synchrotron, synchrotron-radiation, simulation	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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TUPTY070	Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams	luminosity, emittance, simulation, resonance	2192
	M.P. Crouch, R.B. Appleby UMAN, Manchester, United Kingdom B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: STFC HL-LHC The HL-LHC project aims to reach larger peak luminosities, however this can lead to a high pile up in the detectors. To control the pile up, luminosity levelling has been suggested. One proposed method is β-luminosity levelling, in which beams collide at a larger than nominal β. The β* is then reduced in steps as the beam intensity decays. This allows the luminosity to be kept constant over part of a physics fill. The use of round or flat optics will change the beam-beam effect of the head on collisions as well as the long range interactions. Here simulations of β* levelling are presented for the case of flat and round beam optics and the difference in terms of the beam-beam effect is highlighted.
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TUPWI009	Development of Un-destructive Inspection System for Large Concrete Infrastructure by using Accelerator Based Compact Neutron Source	neutron, target, proton, photon	2262
	A. Taketani, H. Baba, T. Hashiguchi, G. Hu, Y. Ikeda, Q. Jia, H. Ota, Y. Otake, Y. Seki, S. Wang, Y. Yamagata, S. Yanagimachi RIKEN, Saitama, Japan K. Hirota Nagoya University, Nagoya, Japan K. Kino Hokkaido University, Sapporo, Japan S. Tanaka KEK, Tsukuba, Japan
	Aged large concrete structure, such as highway, bridges and so on, need to be inspected in order to maintain with less cost by un-destructive method. We have been developing un-destructive inspection system by using fast neutron which can penetrate thick concrete. The system will be consisted of (1) Transportable Accelerator based Neutron Source, (2) Fast neutron imaging detector, and (3) Image processing for getting 3D image. RIKEN Accelerator based compact Neutron Source (RANS), which consists of 7MeV proton LINAC and target station, has been operating since 2013. RANS can generate thermal (~25meV) and fast (~2MeV) neutron. Fast neutron detector are developed with plastic scintillator and semiconductor photon sensors. It can see 10mm thick steel rod with 2mm accuracy through 300mm thick concrete.
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TUPWI019	Neutron Shielding Optimization Studies	neutron, shielding, target, proton	2282
	A. Bungau, R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom J.R. Alonso, L.M. Bartoszek, J.M. Conrad MIT, Cambridge, Massachusetts, USA M. Shaevitz Columbia University, New York, USA
	The IsoDAR sterile-neutrino search calls for a high neutron flux from a 60 MeV proton beam striking a beryllium target, that flood a sleeve of highly-enriched ⁷Li, the beta-decay of the resulting ⁸Li giving the desired neutrinos for the very-short-baseline experiment. The target is placed very close to an existing large neutrino detector; all such existing or planned detectors are deep underground, in low-background environments. It is necessary to design a shielding enclosure to prevent neutrons from causing unacceptable activation of the environment. GEANT4 is being used to study neutron attenuation, and optimizing the layers of shielding material to minimize thickness. Materials being studied include iron and two new types of concrete developed by Jefferson Laboratory, one very light with shredded plastic aggregate, the other with high quantities of boron. Initial studies indicate that a total shielding thickness of 1.5 meters produces the required attenuation factor, further studies may allow decrease in thickness. Minimizing it will reduce the amount of cavity excavation needed to house the target system in confined underground spaces.
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TUPWI048	Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling	luminosity, optics, controls, experiment	2357
	Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen BNL, Upton, Long Island, New York, USA M. Bai FZJ, Jülich, Germany Z. Duan IHEP, Beijing, People's Republic of China
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.
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WEPWA032	CsK2Sb Growth Studies: Towards High Quantum Efficiency and Smooth Surfaces	cathode, simulation, emittance, experiment	2566
	S.G. Schubert, M. Gaowei, J. Sinsheimer, J. Smedley BNL, Upton, Long Island, New York, USA Z. Ding, E.M. Muller SBU, Stony Brook, New York, USA J. Kühn HZB, Berlin, Germany H.A. Padmore, J.J. Wong LBNL, Berkeley, California, USA J. Xie ANL, Argonne, Illinois, USA
	Funding: This work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and the German BMBF, Helmholtz-Association and Land Berlin. The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies with 7% and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a temperature gradient yield a rough surface with a rms roughness in the range of 25 nm. Surface roughness’s in this region impacts the emittance. At an accelerating field of 3 MV/m an rms surface roughness of 25 nm is the dominant effect on emittance and will limit injector performance. Studies are performed to optimize roughness. Various growth procedures are exploited and the surface roughness compared.
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WEPWA043	Progress on the Design of the Racetrack FFAG Decay Ring for nuSTORM	lattice, factory, closed-orbit, resonance	2594
	J.-B. Lagrange, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom R.B. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier UMAN, Manchester, United Kingdom R.B. Appleby Cockcroft Institute, Warrington, Cheshire, United Kingdom Y. Mori Kyoto University, Research Reactor Institute, Osaka, Japan
	The neutrino beam produced from muons decaying in a storage ring would be an ideal tool for precise neutrino cross section measurements and search for sterile neutrinos due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a storage ring, where circulating muon beam would be captured. The racetrack FFAG (Fixed Field Alternating Gradient) option for nuSTORM decay ring offers a very good performance due to a large dynamic and momentum acceptance. Machine parameters, linear optics design, beam dynamics and injection system for nuSTORM FFAG ring are discussed in this paper.
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WEPWA044	The Alignment of the MICE Tracker Detectors	alignment, emittance, experiment, scattering	2597
	M.A. Uchida Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The Muon Ionization Cooling experiment (MICE) has been designed to demonstrate the reduction of the phase-space volume (cooling) occupied by a muon beam using the ionization-cooling technique. This demonstration will be an important step in establishing the feasibility of muon accelerators for particle physics. The emittance of the beam will be measured before and after the cooling cell using a solenoidal spectrometer. Each spectrometer will be instrumented with a high-precision scintillating-fibre tracking detector (Tracker). The Trackers will be immersed in a uniform magnetic field of 4T and will measure the normalised emittance reduction with a precision of 0.1%. A thorough knowledge of the alignment of the Trackers is essential for this accuracy to be achieved. The Trackers are aligned: mechanically inside the spectrometer solenoids, with respect to the MICE experimental hall, to one another, and to the magnetic and beam axes. These methods are described here.
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WEPWA052	RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements	gun, cathode, linac, vacuum	2621
	T.L. Smith, N.P. DiMonte, A. Nassiri, Y.-E. Sun, A. Zholents ANL, Argonne, Illinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357 A new S-band photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the gun’s internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results of RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.
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WEPHA045	Design and Construction of the RF Electronic System at Taiwan Photon Source	cavity, booster, controls, LLRF	3215
	F.-T. Chung, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	The RF electronic system at NSRRC was made fully in house by the RF group from design through construction to completion. The first RF electronic system includes an analogue LLRF system, a step motor, and an ARC module of a Petra cavity. It was successfully integrated with a 100-kW RF transmitter, high-power RF transfer system, and a cooling system and applied to the booster of TPS. Two duplicated RF electronic system were then applied to the storage ring but integrated with the 300-KW transmitters. With these RF systems, the TPS storage ring achieved beam current 100 mA on 2015 March 26.
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WEPTY040	Quench Performance of the First Twin-aperture 11 T Dipole for LHC upgrades	dipole, magnet-design, status, collimation	3361
	A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, G. Chlachidze, A. Nobrega, I. Novitski, S. Stoynev, D. Turrioni Fermilab, Batavia, Illinois, USA B. Auchmann, S. Izquierdo Bermudez, M. Karppinen, L. Rossi, F. Savary, D. Smekens CERN, Geneva, Switzerland
	Funding: *Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy and European Commission under FP7 project HiLumi LHC, GA no.284404 The LHC luminosity upgrade plan foresees installation of additional collimators in Dispersion Suppressor areas around point 7 and interaction regions 1, 2 and 5. The required space for these collimators could be provided by replacing some 15-m long 8.33 T NbTi LHC main dipoles (MB) with shorter 11 T Nb3Sn dipoles (MBH) compatible with the LHC lattice and main systems. FNAL and CERN magnet groups are developing a 5.5-m long twin-aperture dipole prototype with the nominal field of 11 T at the LHC nominal current of 11.85 kA suitable for installation in the LHC. Two of these magnets with a collimator in between will replace one MB dipole. The single-aperture 2-m long dipole demonstrator and two 1-m long dipole models have been assembled and tested at FNAL in 2012-2014. The 1 m long collared coils were then assembled into the first twin-aperture Nb3Sn demonstrator dipole and tested. This paper reports test results of the first twin-aperture Nb3Sn dipole model focusing on magnet training, ramp rate sensitivity and temperature dependence of the magnet quench current. The twin-aperture dipole quench performance is compared with the data for the single-aperture models.
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THPF081	On the Suitability of a Solenoid Horn for the ESS Neutrino Superbeam	solenoid, target, focusing, linac	3873
	M. Olvegård, T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden J.-P. Koutchouk CERN, Geneva, Switzerland
	The European Spallation Source (ESS), now under construction in Lund, Sweden, offers unique opportunities for experimental physics, not only in neutron science but potentially in particle physics. The ESS neutrino superbeam project plans to use a 5 MW proton beam from the ESS linac to generate a high intensity neutrino superbeam, with the final goal of detecting leptonic CP-violation in an underground megaton Cherenkov water detector. The neutrino production requires a second target station and a complex focusing system for the pions emerging from the target. The normal-conducting magnetic horns that are normally used for these applications cannot accept the 2.86 ms long proton pulses of the ESS linac, which means that pulse shortening in an accumulator ring would be required. That, in turn, requires H⁻ operation in the linac to accommodate the high intensity. As an attractive alternative, we investigate the possibility of using superconducting solenoids for the pion focusing. This solenoid horn system needs to also separate positive and negative pion charge as completely as possible, in order to generate separately neutrino and anti-neutrino beams. We present here progress in the study of such a solenoid horn.
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THPF122	The Status of MICE Step IV	solenoid, emittance, experiment, collider	4000
	D. Rajaram Fermilab, Batavia, Illinois, USA V.C. Palladino INFN-Napoli, Napoli, Italy
	Funding: SFTC, DOE, NSF, INFN, CHIPP and more Muon (μ) beams of low emittance provide the basis for the intense, well-characterised neutrino beams of the Neutrino Factory and for 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 μ phase-space volume. In a cooling channel, the μ beam traverses a material (the absorber) in which it looses energy, then replaced longitudinally by RF cavities. The net effect is to reduce transverse emittance(transverse cooling). MICE is being constructed in a series of Steps. At Step IV, MICE will study the properties of liquid hydrogen and lithium hydride that affect cooling. A solenoidal spectrometer will measure emittance up and downstream of the absorber vessel, where a focusing coil will focus muons. The construction of Step IV at RAL is well advanced towards scheduled completion early in 2015. Its status will be described together with a summary of the performance of the principal components. Plans for the commissioning and operation and the Step IV measurement programme will be described.
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Paper

Title

Other Keywords

Page

MOPWA009

Channeling Radiation Experiment at Fermilab ASTA

electron, photon, brilliance, experiment

95

D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Edstrom, P. Piot, T. Sen
Fermilab, Batavia, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.

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MOPWA049

Simulation of Crab Waist Collisions in DAΦNE with KLOE-2 Interaction Region

simulation, luminosity, electron, betatron

229

M. Zobov, A. Drago, A. Gallo, C. Milardi
INFN/LNF, Frascati (Roma), Italy
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404.
After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentially achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e^- ring working point was implemented and resulted in a significant performance increase.

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MOPJE037

Study and Comparison of Mode Damping Strategies for the UA9 Cherenkov Detector Tank

damping, cavity, vacuum, resonance

366

A. Danisi, F. Caspers, R. Losito, A. Masi, B. Salvant, C. Vollinger
CERN, Geneva, Switzerland
T. Demma, P. Lepercq
LAL, Orsay, France

In the framework of the UA9 experiment, the Cherenkov detector is useful to measure the amount of particles deflected by a bent crystal, proving the crystal collimation principle. The tank used to host this device is taken as a case study for an in-depth analysis of different damping strategies for electromagnetic modes which otherwise would give rise to important beam-coupling impedance contributions. Such strategies involve the use of ferrite, damping resistors and a mode-coupler, a solution which intercepts the modes inside the cavity but damps the related power outside the vacuum tank (potentially avoiding heating). Such solutions are discussed through experimental measurements and the relative quality factor is taken as a figure of merit.

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MOPJE064

Beam Impedance Optimization of the TOTEM Roman Pots

impedance, simulation, cavity, vacuum

452

N. Minafra
CERN, Geneva, Switzerland

The TOTEM experiment has been designed to measure the total proton-proton cross section and to study elastic and diffractive scattering at the LHC energy. The measurement requires detecting protons at distances as small as 1 mm from the beam center: TOTEM uses Roman Pots (RP), special beam pipe insertions, to move silicon detectors close to the beams to detect particles very near the beam axis. In the first period of running of the LHC no problems were detected with retracted Roman Pots and during insertions in special runs; however, during close insertions to highest intensity beam, impedance heating has been observed. After the LS1 the LHC beam current will increase and the equipment that can interact with the beam needed to be optimized. A new RP, optimized to minimize the beam coupling, has been designed with the help of CST Particle Studio; a prototype has been used to test the simulation results in the laboratory with wire and probe measurements. Furthermore, in both the old and the new RPs, new ferrites have been installed. The new ferrite material has a higher Curie temperature than the one used before LS1 and a thermal treatment at 1000°C has been applied to reduce the out-gassing.

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MOPJE070

Reduction of Electron Cloud in Particle Accelerator Beampipes Studied by RF Multipacting

electron, injection, vacuum, network

472

R. Leber, F. Caspers, P. Costa Pinto, M. Taborelli
CERN, Geneva, Switzerland

For a given beam structure, chamber geometry and magnetic field configuration, the electron cloud (EC) intensity depends on the Secondary Electron Yield (SEY) of the beam pipe. The reduction of the EC density as a function of machine operation time (scrubbing) is attributed to the growth of a low SEY carbon film induced by electron bombardment. In this paper, we study the time evolution of the conditioning of stainless steel beam pipes in a laboratory setup. The EC or multipacting is induced by Radio-Frequency (RF) fields in a coaxial resonator under vacuum. Strip detectors are used to monitor the current of the EC. Induced pressure rise is simultaneously detected. The multipacting intensity shows a linear dependence on the positive DC bias voltage up to 1000 V, applied to the central electrode. An accelerated conditioning is observed for the applied bias voltage. The SEY of samples exposed to the EC is measured and the surface composition is monitored by X-ray Photoelectron Spectroscopy. The measured SEY, surface composition and multipacting behaviour are well correlated. The injection of acetylene and dodecane during multipacting proved to be ineffective in the conditioning.

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MOPJE071

New Electron Cloud Detectors for the CERN Proton Synchrotron

photon, electron, proton, extraction

476

C. Yin Vallgren, P. Chiggiato, S.S. Gilardoni, H. Neupert, M. Taborelli
CERN, Geneva, Switzerland

Electron cloud (EC) has already been observed during normal operation of the PS using classical shielded button pick-up detectors in drift sections. In the context of the LHC Injector Upgrade (LIU project), similar measurements are also needed for the combined function magnets of the machine, where the access to the vacuum chamber is strongly limited by the presence of the yoke. Two new electron cloud detectors have been studied, developed, and installed during the Long Shutdown (LS1) in one of such magnets. The first is based on current measurement by using a shielded button-type pick-up with a special geometry to reach the bottom surface of the vacuum pipe embedded in the magnet. The second one relies on a newly developed measurement method based on detection of the photons, which are emitted by cathodoluminescence from the electron cloud impinging on the vacuum chamber walls. Part of the emitted photons is collected through a quartz window by a Micro-Channel Plate Photomultiplier Tube (MCP-PMT). First results obtained during machine development runs show the feasibility of the photon detection scheme. The results are discussed and compared with pick-up measurements.

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MOPJE082

Analytical Approach to the Beam-Beam Interaction with the Hourglass Effect

luminosity, coupling, collider, framework

510

M.P. Crouch, R.B. Appleby
UMAN, Manchester, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: STFC HL-LHC
The HL-LHC upgrade will allow higher luminosities to be reached in the LHC. To achieve higher luminosities the β-function at the IP is decreased, which in turn will result in the hourglass effect becoming more prominent as the transverse bunch sizes become comparable to the length of the bunch. This effect reduces the luminosity since not all particles in the bunch will collide at the minimum IP. The standard derivation of the electric and magnetic fields of the beam-beam interaction is that undertaken by Bassetti and Erskine. The derivation by Bassetti Erskine does not include a coupling between bunch planes. When the transverse bunch sizes are comparable to the length of the bunch the magnitude of the transverse kick will be dependent on the longitudinal position. Currently only numerical methods are available to evaluate this effect. Here a theoretical framework is outlined that provides an analytical approach to derive the electric field for the beam-beam interaction with a coupling between the transverse and longitudinal planes.

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MOPMA003

Reconstruction of Electron Bunch Motion During CSR Bursts using Synchronised Diagnostics

electron, synchrotron, radiation, 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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MOPMA005

Non-invasive Beam Profile Monitoring

vacuum, operation, ion, proton

537

C.P. Welsch, T. Cybulski, A. Jeff, V. Tzoganis, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T. Cybulski, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
A. Jeff
CERN, Geneva, Switzerland
V. Tzoganis
RIKEN, Saitama, Japan

Funding: Work supported by the Helmholtz Association under contract VH-NG-328, the EU under contracts 215080 and 289485, as well as the STFC Cockcroft core grant No. ST/G008248/1.
State-of-the-art high energy and high intensity accelerators require new approaches to transverse beam profile monitoring as many established techniques will no longer work due to the high power stored in the beam. In addition, many accelerator applications such as ion beam cancer therapy or material irradiation would benefit significantly from the availability of non-invasive beam profile monitors. Research in the QUASAR Group has focused on this area over the past 5 years. Two different approaches were successfully developed: Firstly, a supersonic gas jet-based monitor was designed and commissioned. It enables the detection of the 2-dimensional transverse beam profile of essentially any charged particle beam with negligible disturbance of the primary beam and accelerator vacuum. Secondly, a monitor based on the Silicon strip VELO detector, originally developed for the LHCb experiment, was tested as an online beam monitor at the Clatterbridge Cancer Center in the UK. The design of both monitors is presented in this contribution. Results from measurements are discussed and complemented by numerical studies into the performance limits of either technique.

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MOPMA031

Simulations of Diamond Detectors with Schottky Contacts

electron, simulation, photon, scattering

617

G.I. Bell, J.R. Cary, D.A. Dimitrov, D. Meiser, D.N. Smithe, C.D. Zhou
Tech-X, Boulder, Colorado, USA
M. Gaowei, E.M. Muller
SBU, Stony Brook, New York, USA
J. Smedley
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences, grant numbers DE-SC0006246 and DE-SC0007577.
We present simulations of semiconductor devices using the code VSim (formerly Vorpal). The 3D simulations involve the movement and scattering of electrons and holes in the semiconductor, voltages which may be applied to external contacts, and self-consistent electrostatic fields inside the device. Particles may experience a Schottky barrier when moving between the semiconductor and a metal contact. Example devices include MOSFETs as well as a diamond X-ray detector. Our code VSim includes scattering models for GaAs and diamond, and runs in parallel on thousands of processors. We compare our simulation results with experimental results from a prototype diamond X-ray detector.

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MOPMA055

MuSim, a Graphical User Interface for Multiple Simulation Programs

simulation, interface, storage-ring, target

678

T.J. Roberts
Muons, Inc, Illinois, USA
P.L. Gueye
Hampton University, Hampton, Virginia, USA

MuSim is a new user-friendly program designed to interface to many different particle simulation codes, regardless of their data formats or geometry descriptions. It presents the user with a compelling graphical user interface that includes a flexible 3-D view of the simulated world plus powerful editing and drag-and-drop capabilities. All aspects of the design can be parametrized so that parameter scans and optimizations are easy. It is simple to create plots and display events in the 3-D viewer (with a slider to vary the transparency of solids), allowing for an effortless comparison of different simulation codes. Simulation codes: G4beamline, MAD-X, and MCNP; more coming. Many accelerator design tools and beam optics codes were written long ago, with primitive user interfaces by today’s standards. MuSim is specifically designed to make it easy to interface to such codes, providing a common user experience for all, and permitting the construction and exploration of models with very little overhead. For today’s technology-driven students, graphical interfaces meet their expectations far better than text-based tools, and education in accelerator physics is one of our primary goals.

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MOPHA007

Modeling/Measurement Comparison of Signal Collection in Diamond Sensors in Extreme Conditions

electron, space-charge, simulation, scattering

787

V. Kubytskyi, P. Bambade, S. Liu
LAL, Orsay, France

Here we present a study of charge collection dynamics in a Diamond Sensor (DS) subjected to intensities from 1 to 10⁸ Minimum Ionizing Particles (MIP). We developed a model based on the numerical solution of the 1D drift-diffusion equations, using the Scharfetter-Gummel discretization scheme. Inhomogeneity of the space-charge distribution together with the externally applied electric field are taken into account by analytically solving the Poisson equation at each time step. We identified two regimes of charge collection. The first corresponds to 1-10⁵ MIPs, in this case the externally applied electric field is negligibly perturbed by space-charge effects during the separation of the electron/hole clouds. The second corresponds to intensities larger than 10⁷ MIPs, where the space-charge effects significantly slow down the charge collection due to large concentrations of electron/hole pairs in the DS volume. The results of our modeling are in qualitative agreement with the experimental data acquired at the PHoto-Injector electron beam facility at LAL. Our model allows optimizing DS parameters to achieve desired charge collection times for different beam intensities.

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MOPHA009

Single-Shot Electro-Optic Sampling Combined With Photonic Time-Stretch: Detailed Results at SOLEIL

laser, synchrotron, storage-ring, real-time

795

C. Szwaj, C. Evain, E. Roussel
PhLAM/CERLA, Villeneuve d'Ascq, France
S. Bielawski
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
J.B. Brubach, L. Cassinari, M.-E. Couprie, M. Labat, L. Manceron, J.P. Ricaud, P. Roy, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France
M. Le Parquier
CERLA, Villeneuve d'Ascq, France

Funding: ANR (DYNACO project), FEDER, CEMPI LABEX.
Single-shot recording of pulses is possible with high repetition rates (more than 80 MHz), as was demonstrated in the framework of a PhLAM-SOLEIL collaboration * **. This can be achieved by a relatively simple upgrade of existing setups based on spectral encoding. The strategy consists to encode the sub-picosecond information into the time domain, but at a slower scale (nanoseconds), using dispersion in a long optical fiber. Then the information is recorded by a photodiode connected to an oscilloscope. In this poster, we present guidelines for the practical realization of the electro-optical setup, as well as a performance analysis. In particular, we analyze the temporal resolution and compare it to the classical electro-optical sampling setup.
* E. Roussel et al., Proceedings of IPAC2014, THOBA01.
** E. Roussel et al., arXiv:1410.7048

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MOPHA023

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

electron, radiation, 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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MOPHA026

Present and Future Optical-to-Microwave Synchronization Systems at REGAE Facility for Electron Diffraction and Plasma Acceleration Experiments

laser, electron, timing, plasma

833

M. Titberidze, F.J. Grüner, A.R. Maier, B. Zeitler
CFEL, Hamburg, Germany
S.W. Epp
MPSD, Hamburg, Germany
M. Felber, K. Flöttmann, T. Lamb, U. Mavrič, J.M. Müller, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
F.J. Grüner, A.R. Maier, M. Titberidze
Uni HH, Hamburg, Germany
E. Janas
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Relativistic Electron Gun for Atomic Explorations (REGAE) is a Radio Frequency (RF) driven linear accelerator. It uses frequency tripled short photon pulses (~ 35 fs) from the Titanium Sapphire (Ti:Sa.) Laser system in order to generate electron bunches from the photo-cathode. The electron bunches are accelerated up to ~ 5 MeV kinetic energy and compressed down to sub-10 fs using the so called ballistic bunching technique. REGAE currently is used for electron diffraction experiments (by Prof. R.J.D. Miller's Group). In near future within the collaboration of Laboratory for Laser- and beam-driven plasma Acceleration (LAOLA), REGAE will also be employed to externally inject electron bunches into laser driven linear plasma waves. Both experiments require very precise synchronization (sub-50 fs) of the photo-injector laser and RF reference. In this paper we present experimental results of the current and new optical to microwave synchronization systems in comparison. We also address some of the issues related to the current system and give an upper limit in terms of its long-term performance.

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MOPHA027

Transverse Emittance Measurement at REGAE

emittance, electron, background, solenoid

837

M. Hachmann, K. Flöttmann
DESY, Hamburg, Germany

The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.

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MOPHA037

Visible Light Diagnostics at the ANKA Storage Ring

synchrotron, photon, diagnostics, radiation

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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MOPHA040

First Results of Energy Measurements with a Compact Compton Backscattering Setup at ANKA

laser, electron, photon, storage-ring

876

C. Chang, E. Bründermann, E. Hertle, N. Hiller, E. Huttel, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann
KIT, Karlsruhe, Germany
H.-W. Hübers, H. Richter
DLR, Berlin, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
An electron energy measurement setup based on the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam, has been proposed and developed for operation at the ANKA storage ring of the Karlsruhe Institute of Technology (KIT). In contrast to conventional methods based on head-on collisions, the setup at ANKA is, for the first time, realized in a transverse configuration where the laser beam hits the electron beam at an angle of ~90°. This makes it possible to achieve a relatively low-cost and very compact setup since it only requires a small side-port instead of a straight section. This development could benefit storage rings with restricted space or where no straight sections are available, for example due to interferences with existing beamlines. The setup and the first measurement results are presented in the paper.

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MOPHA043

Properties of Transition- and Synchrotron Radiation at FLUTE

radiation, synchrotron, synchrotron-radiation, electron

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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MOPHA048

Beam Optimization of the DAΦNE Beam Test Facility

diagnostics, linac, software, electron

901

L.G. Foggetta, B. Buonomo
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The DAΦNE Beam Test Facility delivers electron and positron beam with a wide spread of parameters in charge, energy, transverse dimensions and time width. Thanks to the recent improvements of the diagnostics, all the beam parameters have been measured and optimized. In particular we report here some results on beam transverse size, divergence, and position stability for different energy and intensity configurations. After the upgrade of the electronic gun of the DAΦNE LINAC, the pulse time width and charge distribution have been also characterized.

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MOPHA049

Evolution of Diagnostics and Services of the DAΦNE Beam Test Facility

vacuum, linac, controls, diagnostics

904

L.G. Foggetta, B. Buonomo
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The DAΦNE Beam Test Facility (BTF) is operational in Frascati since 2003. In the last years the beam diagnostics tools have been completely renewed and the services for users have been largely improved. We describe here the new transverse beam diagnostics based on new GEM TPC detectors and Timepix/FitPix, the new BTF network layout, the renewed DAQ system including the BCM detectors, the data caching system based on MEMCached and the integration of the new sub-systems in the new data-logging. All other services, such as the environmental monitoring system, vacuum system, payload remote handling, and gas distribution have been also improved.

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MOPHA051

Scintillating Fibers used as Profile Monitors for the CNAO HEBT Lines

proton, ion, extraction, vacuum

910

E. Rojatti
UniPV, Pavia, Italy
J. Bosser, M. Haguenauer, P. Poilleux
CERN, Geneva, Switzerland
J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, M. Pullia, C. Viviani
CNAO Foundation, Milan, Italy
M. Caldara
University of Bergamo, Bergamo, Italy

The CNAO (Centro Nazionale di Adroterapia Oncologica) Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions. Several beam monitors exploiting the scintillation process have been designed to check the beam quality in the extraction lines, in order to guarantee patients safety. The SFH (Scintillating Fibers Harp), the QPM (Qualification Profile Monitor), and the SFP (Scintillating Fibers plus Photodiodes) are made up by two orthogonal scintillating fibers harps with not dead area for the horizontal and the vertical beam profiles measurement. The QPM and the SFH are both installed on the beam line and they use a CCD camera for the signal acquisition. The SFP is a SFH upgrade project aimed to replace the camera with two Photodiodes arrays coupled to the fibers in vacuum. The WD (Watch Dog) detector, not already installed, has been designed to check the beam position through the intensity of the beam tails. It uses two couples of scintillating fibers displaced transversally to the beam direction, coupled to four APDs (Avalanche Photodiodes). This work describes the beam detectors, their achieved performances and the most recent beam measurements.

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MOPHA053

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

cavity, linac, coupling, radiation

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, radiation, 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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MOPTY011

Operation Experience of p-Carbon Polarimeter in RHIC

target, polarization, vacuum, operation

956

H. Huang, E.C. Aschenauer, G. Atoian, A. Bazilevsky, O. Eyser, D. Kalinkin, J. Kewisch, Y. Makdisi, S. Nemesure, A. Poblaguev, W.B. Schmidke, D. Smirnov, D. Steski, K. Yip, A. Zelenski
BNL, Upton, Long Island, New York, USA
I.G. Alekseev, D. Svirida
ITEP, Moscow, Russia

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The spin physics program in Relativistic Heavy Ion Collider (RHIC) requires fast polarimeter to monitor the polarization evolution on the ramp and during stores. Over past decade, the polarimeter has evolved greatly to improve its performance. These include dual chamber design, monitoring camera, Si detector selection (and orientation), target quality control, and target frame modification. The preamp boards have been modified to deal with the high rate problem, too. The ultra thin carbon target lifetime is a concern. Simulations have been carried out on the target interaction with beam. Modification has also been done on the frame design. Extra caution has been put on RF shielding to deal with the pickup noises from the nearby stochastic cooling kickers. This paper summarizes the recent operation performance of this delicate device.

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MOPTY016

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

radiation, 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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MOPTY041

Prototype Results with a Complete Beam Loss Monitor System Optimized for Synchrotron Light Sources

electron, injection, electronics, impedance

1019

P. Leban
I-Tech, Solkan, Slovenia
K.B. Scheidt
ESRF, Grenoble, France

Beam loss monitors in synchrotron light sources are finding an increasing utility in particular with the trend of numerous light sources pushing to lower emittances and thus higher intra-beam scattering, while operating in top-up injection modes and employing in-vacuum undulators in their rings. The development of an optimized electron BeamLoss Monitor aims at fulfilling, in one single system, all possible functionalities and applications like both the measurement of fast-time-resolved losses at injection and the possibility of ultra-sensitive detection of low & slow electron loss level variations. This optimized beam loss monitor system comprises both the acquisition electronics and up to four sensor head per unit. The sensor heads themselves, that can be configured for different sizes or volumes, are based on the detection of the electromagnetic shower resulting from an electron loss through the use of either Cherenkov radiator or gamma scintillator and a photomultiplier tube, all assembled in a single compact housing ready for installation.

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MOPTY047

ESS Cold LINAC BLM Locations Determination

simulation, linac, quadrupole, proton

1039

M. Jarosz, A. Jansson, J.C. Kazantzidis, T.J. Shea, L. Tchelidze
ESS, Lund, Sweden

Funding: This project (oPAC) is funded by the European Union under contract PITN-GA-2011-289485.
The linear accelerator of ESS will produce a 5 MW proton beam. Beam of this power must be strictly monitored by a specialized Beam Loss Monitoring (BLM) System to detect any abnormal losses and to ensure that operational losses do not lead to excessive activation. A long series of beam loss simulations was performed using MARS Monte Carlo code system in order to optimize the number and setting mounting locations of the detectors for best coverage, distinguishability and sensitivity. Simulations anticipated multiple possible beam loss scenarios resulting in different loss patterns. The results of energy deposition in air in the linac tunnel in multiple locations were analysed in several different ways. Incorporated methods varied from simple brute force approach to more sophisticated singular value decomposition based algorithms, all resulting in detector layout proposals. Locations selected for BLMs were evaluated for all methods.

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MOPTY055

Beam Loss Monitoring for Run 2 of the LHC

monitoring, injection, database, beam-losses

1057

M.K. Kalliokoski, B. Auchmann, B. Dehning, F.S. Domingues Sousa, E. Effinger, J. Emery, V. Grishin, E.B. Holzer, S. Jackson, B. Kolad, E. Nebot Del Busto, O. Picha, C. Roderick, M. Sapinski, M. Sobieszek, C. Zamantzas
CERN, Geneva, Switzerland

The Beam Loss Monitoring (BLM) system of the LHC consists of over 3600 ionization chambers. The main task of the system is to prevent the superconducting magnets from quenching and protect the machine components from damage, as a result of critical beam losses. The BLM system therefore requests a beam abort when the measured dose in the chambers exceeds a threshold value. During Long Shutdown 1 (LS1) a series of modifications were made to the system. Based on the experience from Run 1 and from improved simulation models, all the threshold settings were revised, and modified where required. This was done to improve the machine safety at 7 TeV, and to reduce beam abort requests when neither a magnet quench or damage to machine components is expected. In addition to the updates of the threshold values, about 800 monitors were relocated. This improves the response to unforeseen beam losses in the millisecond time scale due to micron size dust particles present in the vacuum chamber. This contribution will discuss all the changes made to the BLM system, with the reasoning behind them.

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MOPTY057

Feasibility Study of Monitoring the Population of the CERN-LHC Abort Gap with Diamond Based Particle Detectors

beam-losses, monitoring, kicker, simulation

1065

O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann
CERN, Geneva, Switzerland

At the end of a physics fill and in case of a failure, the LHC beams must be extracted and transferred through a 750m long line to the beam dump block. During the rise of the extraction kickers to their full strength a particle-free abort gap, with a length of 3 us in the LHC filling pattern, is required to prevent beam losses that could lead to substantial quenching of magnets, with a risk of damage. Therefore the particle population in the abort gap, which is mainly due to un-bunched beam, is monitored. Above a certain threshold an active cleaning by excitation of betatron oscillations with the transverse feedback system is initiated. This paper describes a novel method of monitoring the abort gap population using diamond particle detectors for detecting the interactions of beam in the abort gap with neon gas, injected in the beam pipe. Two different layouts of the system and the expected interaction and detection rates are discussed.

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MOPTY058

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

electron, experiment, radiation, 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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MOPTY080

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

storage-ring, synchrotron, radiation, 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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MOPWI003

Laserwire Emittance Scanner at CERN Linac 4

laser, linac, emittance, ion

1146

K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.

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MOPWI010

Design and Development of a Beam Stablity Mechanical Motion System Diagnostic for the APS MBA Upgrade

vacuum, insertion, insertion-device, ground-motion

1164

R.M. Lill, G. Decker, N. Sereno, B.X. Yang
ANL, Argonne, Ilinois, USA

Funding: Results shown in this report result from work performed at Argonne National Laboratory operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357.
The Advanced Photon Source (APS) is currently in the conceptual design phase for the MBA lattice upgrade. In order to achieve long-term beam stability goals, a Mechanical Motion System (MMS) has been designed to monitor critical in-tunnel beam position monitoring devices. The mechanical motion generated from changes in chamber cooling water temperature, tunnel air temperature, beam current and undulator gap positon causes erroneous changes in beam position measurements causing drift in the X-ray beam position. The MMS has been prototyped and presently provides critical information on the vacuum chamber and BPM support systems. We report on first results of the prototype system installed in the APS storage ring.

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MOPWI017

Beam Extinction Monitoring in the Mu2e Experiment

proton, target, experiment, shielding

1185

E. Prebys, A. Gaponenko, P.H. Kasper
Fermilab, Batavia, Illinois, USA
L.M. Bartoszek
Bartoszek Engineering, Aurora, Illinois, USA

Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359.
The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10^-10 fractional level. The verification of this level of extinction is very challenging. The proposed technique uses a special purpose spectrometer which will observe particles scattered from the production target of the experiment. The acceptance will be limited such that there will be no saturation effects from the in-time beam. The precise level and profile of the out-of-time beam can then be built up statistically, by integrating over many bunches.

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MOPWI029

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

electron, lattice, laser, radiation

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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MOPWI036

Investigation of Continuous Scan Methods for Rapid Data Acquisition

data-acquisition, software, experiment, hardware

1243

C.L. Li
East China University of Science and Technology, Shanghai, People's Republic of China
A.M. Kiss
SLAC, Menlo Park, California, USA
W.J. Zhang
University of Saskatchewan, Saskatoon, Canada

It is common practice to perform spatially resolved X ray data acquisition by automatically moving components to discrete locations and then measuring beam intensity with the system at rest. While effective, scanning in this manner can be time consuming, with motors needing to accelerate, move and decelerate at each location before recording data. Information between data points may be missed unless fine grid scans are performed, which accounts for a further increase of scan time. Recent advances in commercial hardware and software enables a continuous scan capability for a wide range of applications, which saves the start and end of step motors. To compare scanning performance, both step and continuous scan modes were examined using the SPEC command language with both commercial and in-house hardware. The advantages and limitations of each are discussed.

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MOPWI052

Responsivity Study of Diamond X-ray Monitors with nUNCD Contact

photon, synchrotron, plasma, database

1273

M. Gaowei, J. Smedley
BNL, Upton, Long Island, New York, USA
E.M. Muller, T. Zhou
SBU, Stony Brook, New York, USA
A.V. Sumant
Argonne National Laboratory, Center for Nanoscale Materials, Argonne, USA

Nitrogen doped ultrananocrystalline diamond (nUNCD) grown on the surface of a CVD single crystal diamond is tested at various beamlines covering an x-ray photon energy range of 200eV to 28 keV. The nUNCD has much lower x-ray absorption than metal contacts and is designed to improve the performance of our device. The responsivity of nUNCD diamond x-ray detector is compared with the conventional platinum coated diamond x-ray beam position monitor and the results are presented in this paper.

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TUAC3

Optimization of Beam Loss Monitor Network for Fault Modes

cavity, network, simulation, lattice

1356

Z. Liu, Z.Q. He, S.M. Lidia, D. Liu, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Beam Loss Monitoring (BLM) System is an essential part to protect accelerator from machine faults. Compared with the empirical or uniform BLM arrangement in most accelerators, our new optimization approach proposes a “minimum spatial distribution” for BLM network. In this distribution, BLMs shall be placed at a small set of “critical positions” that can detect all failure / FPS trigger-able events of each fault mode. In additional, to implement a more advanced function of fault diagnosis, BLM should also be placed at “discrimination points” for fault-induced loss pattern recognition. With examples of FRIB failure event simulations, the author demonstrates the proof of concept to locate these “critical positions” and “discrimination points” for the minimum spatial distribution of BLMs.

Slides TUAC3 [2.341 MB]

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TUPWA016

Modeling of beam losses at ESRF

vacuum, scattering, simulation, electron

1430

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

As the ESRF enters the second phase of its upgrade towards ultra low emittance, the knowledge of the beam loss pattern around the storage ring is needed for radiation safety calculations and for the new machine design optimization. A model has been developed to simulate the Touschek scattering and the scattering of electrons on residual gas nuclei in view of producing a detailed loss map of the machine. Results of simulation for the ESRF are presented and compared with real beam measurements.

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TUPWA066

Development of a High Average Power Laser for High Brightness X-ray Source and Imaging at cERL

laser, cavity, electron, photon

1579

A. Kosuge, T. Akagi, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
R. Hajima, M. Mori, T. Shizuma
JAEA, Ibaraki-ken, Japan
R. Nagai
JAEA/ERL, Ibaraki, Japan

Funding: This study is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT, Japan.
High brightness X-rays via laser-Compton scattering (LCS) of laser photons stored in an optical cavity by a relativistic electron beam is useful for many scientific and industrial applications such as X-ray imaging. The construction of compact Energy Recovery Linac (cERL) is now in progress at KEK to generate low-emittance and high-current electron beams. In order to demonstrate the generation of high brightness LCS X-rays, it is necessary to develop a high average power injection laser and an optical four-mirror ring cavity with two concave mirrors which is used to produce a small spot laser beam inside the cavity. In this presentation, we will show the result of the development of the high average laser system, the LCS X-rays generation, and the X-ray imaging.

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TUPJE012

Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments

laser, synchrotron, experiment, timing

1638

J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou
IHEP, Beijing, People's Republic of China

Funding: This work is supported by the NSFC under grant No.11305186
R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.

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TUPJE055

The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State

electron, cathode, brightness, vacuum

1748

L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.E. Scheibler, A.S. Terekhov
ISP, Novosibirsk, Russia

The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and is increased significantly if the mean values of these quantities are reduced. To address this, ASTeC constructed a Transverse Energy Spread Spectrometer (TESS)* – an experimental facility designed to measure these transverse and longitudinal energy distributions which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. We present measurements showing evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Photocathodes were activated to negative electron affinity in our photocathode preparation facility (PPF)** with quantum efficiency around 10.5%. They were then transferred to TESS under XHV conditions, and progressively degraded through controlled exposure to oxygen. Data has been collected under photocathode illumination at 635 nm, and demonstrates a constant relationship between energy distribution and the level of electron affinity.
* Proc. FEL ’13, TUPPS033, 290-293
** Proc. IPAC '10, TUPE095, 2347-2349, Proc. IPAC ’11, THPC129, 3185-3187

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TUPMA008

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

impedance, space-charge, simulation, radiation

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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TUPMA017

Pulsed-wire Measurements for Insertion Devices

undulator, electron, FEL, laser

1869

A. D'Audney, S. Biedron, S.V. Milton, S.A. Stellingwerff
CSU, Fort Collins, Colorado, USA

The performance of a Free Electron Laser (FELs) depends in part on the integrity of the magnetic field in the undulator. The magnetic field on the axis of the undulator is transverse and sinusoidally varying due to the periodic sequence of dipoles. The ideal trajectory of a relativistic electron bunch, inserted along the axis, is sinusoidal in the plane of oscillation. Phase errors are produced when the path of the electron is not the ideal sinusoidal trajectory, due to imperfections in the magnetic field. The result of such phase errors is a reduction of laser gain impacting overall FEL performance. A pulsed-wire method can be used to determine the profile of the magnetic field. This is achieved by sending a square current pulse through the wire, which will induce an interaction with the magnetic field. Measurement of the displacement in the wire over time using a motion detector yields the first or second integrals of the magnetic field. Dispersion in the wire can be corrected using algorithms resulting in higher accuracy. Once the fields are known, magnetic shims are placed where any corrections are needed.

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TUPMA036

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

photon, radiation, 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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TUPTY004

Tracking Simulation for Beam Loss Studies with Application to FCC

simulation, lattice, scattering, collider

2004

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

We present an implementation of a tracking simulation tool used to evaluate the main particle loss effects for Flavor Factories with the aim of applying these studies also to FCC. We describe the interface of the Monte Carlo tracking code with MAD-X, showing first simulations of the Touschek effect for the FCC-ee at the Z. We plan to use this approach also for multi-turn simulations of particles scattered by radiative Bhabha, beam-gas and eventually Beamstrahlung effects.

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TUPTY011

A Preliminary Design of the CEPC Interaction Region

interaction-region, dynamic-aperture, quadrupole, luminosity

2019

Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Geng, D. Wang, Y.S. Zhu
IHEP, Beijing, People's Republic of China

CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×10³⁴/cm²/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.

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TUPTY016

Study of Background and MDI Design for CEPC

background, scattering, photon, simulation

2028

Y. Yue, Q. Qin
IHEP, Beijing, People's Republic of China

CEPC is a project designed to obtain a large number of Higgs events by keeping e⁺e⁻ collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 10³⁴ cm^-2 s^-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.

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TUPTY017

Ion Polarization Control in the MPD and SPD Detectors of the NICA Collider

polarization, solenoid, collider, proton

2031

A.D. Kovalenko, A.V. Butenko, V.D. Kekelidze, V.A. Mikhaylov
JINR, Dubna, Moscow Region, Russia
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Two solenoid Siberian snakes are placed in the opposite collider’s straight sections are used to control deuteron’s and proton’s polarization in the NICA collider. Solenoid snakes substantially reconstruct beam’s orbital motion. The change of the polarization direction in the vertical plane of MPD and SPD detectors occurs due to insertion of polarization control (PC) solenoids in the magnetic lattice of the collider. The solenoids rotating particle’s spin by small angels practically do not influence on the beam’s orbital motion parameters. The dynamic of the polarization vector as function of the orbit length for cases of longitudinal and vertical polarization in the MPD and SPD detectors are presented.

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TUPTY031

Tools for Flexible Optimisation of IR Designs with Application to FCC

radiation, synchrotron, synchrotron-radiation, simulation

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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TUPTY070

Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams

luminosity, emittance, simulation, resonance

2192

M.P. Crouch, R.B. Appleby
UMAN, Manchester, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: STFC HL-LHC
The HL-LHC project aims to reach larger peak luminosities, however this can lead to a high pile up in the detectors. To control the pile up, luminosity levelling has been suggested. One proposed method is β*-luminosity levelling, in which beams collide at a larger than nominal β*. The β* is then reduced in steps as the beam intensity decays. This allows the luminosity to be kept constant over part of a physics fill. The use of round or flat optics will change the beam-beam effect of the head on collisions as well as the long range interactions. Here simulations of β* levelling are presented for the case of flat and round beam optics and the difference in terms of the beam-beam effect is highlighted.

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TUPWI009

Development of Un-destructive Inspection System for Large Concrete Infrastructure by using Accelerator Based Compact Neutron Source

neutron, target, proton, photon

2262

A. Taketani, H. Baba, T. Hashiguchi, G. Hu, Y. Ikeda, Q. Jia, H. Ota, Y. Otake, Y. Seki, S. Wang, Y. Yamagata, S. Yanagimachi
RIKEN, Saitama, Japan
K. Hirota
Nagoya University, Nagoya, Japan
K. Kino
Hokkaido University, Sapporo, Japan
S. Tanaka
KEK, Tsukuba, Japan

Aged large concrete structure, such as highway, bridges and so on, need to be inspected in order to maintain with less cost by un-destructive method. We have been developing un-destructive inspection system by using fast neutron which can penetrate thick concrete. The system will be consisted of (1) Transportable Accelerator based Neutron Source, (2) Fast neutron imaging detector, and (3) Image processing for getting 3D image. RIKEN Accelerator based compact Neutron Source (RANS), which consists of 7MeV proton LINAC and target station, has been operating since 2013. RANS can generate thermal (~25meV) and fast (~2MeV) neutron. Fast neutron detector are developed with plastic scintillator and semiconductor photon sensors. It can see 10mm thick steel rod with 2mm accuracy through 300mm thick concrete.

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TUPWI019

Neutron Shielding Optimization Studies

neutron, shielding, target, proton

2282

A. Bungau, R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom
J.R. Alonso, L.M. Bartoszek, J.M. Conrad
MIT, Cambridge, Massachusetts, USA
M. Shaevitz
Columbia University, New York, USA

The IsoDAR sterile-neutrino search calls for a high neutron flux from a 60 MeV proton beam striking a beryllium target, that flood a sleeve of highly-enriched ⁷Li, the beta-decay of the resulting ⁸Li giving the desired neutrinos for the very-short-baseline experiment. The target is placed very close to an existing large neutrino detector; all such existing or planned detectors are deep underground, in low-background environments. It is necessary to design a shielding enclosure to prevent neutrons from causing unacceptable activation of the environment. GEANT4 is being used to study neutron attenuation, and optimizing the layers of shielding material to minimize thickness. Materials being studied include iron and two new types of concrete developed by Jefferson Laboratory, one very light with shredded plastic aggregate, the other with high quantities of boron. Initial studies indicate that a total shielding thickness of 1.5 meters produces the required attenuation factor, further studies may allow decrease in thickness. Minimizing it will reduce the amount of cavity excavation needed to house the target system in confined underground spaces.

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TUPWI048

Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling

luminosity, optics, controls, experiment

2357

Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen
BNL, Upton, Long Island, New York, USA
M. Bai
FZJ, Jülich, Germany
Z. Duan
IHEP, Beijing, People's Republic of China

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.

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WEPWA032

CsK2Sb Growth Studies: Towards High Quantum Efficiency and Smooth Surfaces

cathode, simulation, emittance, experiment

2566

S.G. Schubert, M. Gaowei, J. Sinsheimer, J. Smedley
BNL, Upton, Long Island, New York, USA
Z. Ding, E.M. Muller
SBU, Stony Brook, New York, USA
J. Kühn
HZB, Berlin, Germany
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
J. Xie
ANL, Argonne, Illinois, USA

Funding: This work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and the German BMBF, Helmholtz-Association and Land Berlin.
The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies with 7% and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a temperature gradient yield a rough surface with a rms roughness in the range of 25 nm. Surface roughness’s in this region impacts the emittance. At an accelerating field of 3 MV/m an rms surface roughness of 25 nm is the dominant effect on emittance and will limit injector performance. Studies are performed to optimize roughness. Various growth procedures are exploited and the surface roughness compared.

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WEPWA043

Progress on the Design of the Racetrack FFAG Decay Ring for nuSTORM

lattice, factory, closed-orbit, resonance

2594

J.-B. Lagrange, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
R.B. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
UMAN, Manchester, United Kingdom
R.B. Appleby
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

The neutrino beam produced from muons decaying in a storage ring would be an ideal tool for precise neutrino cross section measurements and search for sterile neutrinos due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a storage ring, where circulating muon beam would be captured. The racetrack FFAG (Fixed Field Alternating Gradient) option for nuSTORM decay ring offers a very good performance due to a large dynamic and momentum acceptance. Machine parameters, linear optics design, beam dynamics and injection system for nuSTORM FFAG ring are discussed in this paper.

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WEPWA044

The Alignment of the MICE Tracker Detectors

alignment, emittance, experiment, scattering

2597

M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Muon Ionization Cooling experiment (MICE) has been designed to demonstrate the reduction of the phase-space volume (cooling) occupied by a muon beam using the ionization-cooling technique. This demonstration will be an important step in establishing the feasibility of muon accelerators for particle physics. The emittance of the beam will be measured before and after the cooling cell using a solenoidal spectrometer. Each spectrometer will be instrumented with a high-precision scintillating-fibre tracking detector (Tracker). The Trackers will be immersed in a uniform magnetic field of 4T and will measure the normalised emittance reduction with a precision of 0.1%. A thorough knowledge of the alignment of the Trackers is essential for this accuracy to be achieved. The Trackers are aligned: mechanically inside the spectrometer solenoids, with respect to the MICE experimental hall, to one another, and to the magnetic and beam axes. These methods are described here.

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WEPWA052

RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements

gun, cathode, linac, vacuum

2621

T.L. Smith, N.P. DiMonte, A. Nassiri, Y.-E. Sun, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
A new S-band photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the gun’s internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results of RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.

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WEPHA045

Design and Construction of the RF Electronic System at Taiwan Photon Source

cavity, booster, controls, LLRF

3215

F.-T. Chung, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

The RF electronic system at NSRRC was made fully in house by the RF group from design through construction to completion. The first RF electronic system includes an analogue LLRF system, a step motor, and an ARC module of a Petra cavity. It was successfully integrated with a 100-kW RF transmitter, high-power RF transfer system, and a cooling system and applied to the booster of TPS. Two duplicated RF electronic system were then applied to the storage ring but integrated with the 300-KW transmitters. With these RF systems, the TPS storage ring achieved beam current 100 mA on 2015 March 26.

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WEPTY040

Quench Performance of the First Twin-aperture 11 T Dipole for LHC upgrades

dipole, magnet-design, status, collimation

3361

A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, G. Chlachidze, A. Nobrega, I. Novitski, S. Stoynev, D. Turrioni
Fermilab, Batavia, Illinois, USA
B. Auchmann, S. Izquierdo Bermudez, M. Karppinen, L. Rossi, F. Savary, D. Smekens
CERN, Geneva, Switzerland

Funding: *Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy and European Commission under FP7 project HiLumi LHC, GA no.284404
The LHC luminosity upgrade plan foresees installation of additional collimators in Dispersion Suppressor areas around point 7 and interaction regions 1, 2 and 5. The required space for these collimators could be provided by replacing some 15-m long 8.33 T NbTi LHC main dipoles (MB) with shorter 11 T Nb3Sn dipoles (MBH) compatible with the LHC lattice and main systems. FNAL and CERN magnet groups are developing a 5.5-m long twin-aperture dipole prototype with the nominal field of 11 T at the LHC nominal current of 11.85 kA suitable for installation in the LHC. Two of these magnets with a collimator in between will replace one MB dipole. The single-aperture 2-m long dipole demonstrator and two 1-m long dipole models have been assembled and tested at FNAL in 2012-2014. The 1 m long collared coils were then assembled into the first twin-aperture Nb3Sn demonstrator dipole and tested. This paper reports test results of the first twin-aperture Nb3Sn dipole model focusing on magnet training, ramp rate sensitivity and temperature dependence of the magnet quench current. The twin-aperture dipole quench performance is compared with the data for the single-aperture models.

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THPF081

On the Suitability of a Solenoid Horn for the ESS Neutrino Superbeam

solenoid, target, focusing, linac

3873

M. Olvegård, T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
J.-P. Koutchouk
CERN, Geneva, Switzerland

The European Spallation Source (ESS), now under construction in Lund, Sweden, offers unique opportunities for experimental physics, not only in neutron science but potentially in particle physics. The ESS neutrino superbeam project plans to use a 5 MW proton beam from the ESS linac to generate a high intensity neutrino superbeam, with the final goal of detecting leptonic CP-violation in an underground megaton Cherenkov water detector. The neutrino production requires a second target station and a complex focusing system for the pions emerging from the target. The normal-conducting magnetic horns that are normally used for these applications cannot accept the 2.86 ms long proton pulses of the ESS linac, which means that pulse shortening in an accumulator ring would be required. That, in turn, requires H⁻ operation in the linac to accommodate the high intensity. As an attractive alternative, we investigate the possibility of using superconducting solenoids for the pion focusing. This solenoid horn system needs to also separate positive and negative pion charge as completely as possible, in order to generate separately neutrino and anti-neutrino beams. We present here progress in the study of such a solenoid horn.

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THPF122

The Status of MICE Step IV

solenoid, emittance, experiment, collider

4000

D. Rajaram
Fermilab, Batavia, Illinois, USA
V.C. Palladino
INFN-Napoli, Napoli, Italy

Funding: SFTC, DOE, NSF, INFN, CHIPP and more
Muon (μ) beams of low emittance provide the basis for the intense, well-characterised neutrino beams of the Neutrino Factory and for 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 μ phase-space volume. In a cooling channel, the μ beam traverses a material (the absorber) in which it looses energy, then replaced longitudinally by RF cavities. The net effect is to reduce transverse emittance(transverse cooling). MICE is being constructed in a series of Steps. At Step IV, MICE will study the properties of liquid hydrogen and lithium hydride that affect cooling. A solenoidal spectrometer will measure emittance up and downstream of the absorber vessel, where a focusing coil will focus muons. The construction of Step IV at RAL is well advanced towards scheduled completion early in 2015. Its status will be described together with a summary of the performance of the principal components. Plans for the commissioning and operation and the Step IV measurement programme will be described.

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