IBIC2013 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOCL1	Beam Instrumentation at the Accelerator Test Facility 2	laser, electron, OTR, feedback	26
	S.T. Boogert JAI, Egham, Surrey, United Kingdom S.T. Boogert Royal Holloway, University of London, Surrey, United Kingdom
	The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. Four OTR (Optical Transition Radiation) monitors have been installed at the ATF2. Major characteristics is the fast measurement of projected (2D) and intrinsic (4D) emittances and the coupling corrections with skew quadrupole magnets at the upstream. The high resolution cavity beam position monitor (BPM) system is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.426 GHz, and S-band at 2.888 GHz with an increased beam aperture. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1 μm for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm. A laser-wire transverse electron beam size measurement system has been constructed and operated at the ATF2 beam line at KEK. A special set of electron beam optics was developed to generate an approximately 1μm vertical focus at the laser-wire location. Systematic measurements of a micron beam size have been successfully executed.
	Slides MOCL1 [6.059 MB]

MOCL3	Emittance and Momentum Diagnostics for Beams with Large Momentum Spread	quadrupole, CLIC, diagnostics, transverse	37
	M. Olvegård, V.G. Ziemann Uppsala University, Uppsala, Sweden
	In the drive beam complex of CLIC, but also in plasma wakefield accelerators, the momentum spread can be on the order of tens of percent while conventional diagnostic methods often assume a very small momentum spread. This leads to systematic misinterpretations of the measurements. Spectrometry and emittance measurements based on quadrupole scan rely on measuring the beam size, which depends on the beam envelope. This, in turn, depends on the momentum distribution. We have studied the systematic errors that arise and developed novel algorithms to correctly analyze these measurements for arbitrary momentum distributions. As an application we consider the CLIC drive beam decelerator, where extraction of up to 90% of the kinetic energy leads to a very large momentum spread. We study a measurement of the time-resolved momentum distribution, based on sweeping the beam in a circular pattern and recording the beam size on a screen using optical transition radiation. We present the algorithm to extract the time-resolved momentum distribution, together with simulation results to prove its applicability.
	Slides MOCL3 [2.984 MB]

MOPC03	Overview of the ESS-Bilbao Mobile Diagnostics Test Stand	ESS, rfq, diagnostics, transverse	45
	D. Belver, I. Arredondo, I. Bustinduy, P. Echevarria, J. Feuchtwanger, Z. Izaola, J. Ortega Mintegui, S. Varnasseri ESS Bilbao, Zamudio, Spain
	A MObile diagnostics Test Stand (MOTS) is being designed at ESS-Bilbao in order to characterize the beam at the end of the Radio Frequency Quadrupole (RFQ) at 3 MeV. Injection of the beam from the RFQ to the Drift Tube Linac (DTL) tank and acceleration up to 12 MeV is a sensitive operation in the accelerating chain. The output beam of the RFQ should be fully characterized and tuned to optimize this operation. To perform this characterization the MOTS is being designed with a set of diagnostics devices to measure also beam parameters after the Medium Energy Beam Transport (MEBT), and with minor modifications after the first tank of the DTL. The most important beam parameters that will be measured with the test stand are the beam current, the beam energy and the energy spread. Other important parameters are the beam emittance, the transverse beam position and the profile and bunch length. This contribution describes the beam properties that will be measured and the corresponding instrumentation devices, and presents a general layout of the MOTS.
	Poster MOPC03 [1.146 MB]

MOPC04	Electron Beam Collimation for Slice Diagnostics and Generation of Femtosecond Soft X-Ray Pulses from a Free Electron Laser	electron, diagnostics, collimation, FEL	49
	S. Di Mitri, M. Bossi, D. Castronovo, I. Cudin, M. Ferianis, L. Fröhlich Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	We present the experimental results of femtosecond slicing an ultra-relativistic, high brightness electron beam with a collimator. We demonstrate that the collimation process preserves the slice beam quality, in agreement with our theoretical expectations, and that the collimation is compatible with the operation of a linear accelerator. Thus, it turns out to be a more compact and cheaper solution for electron slice diagnostics than commonly used radiofrequency deflecting cavities and having minimal impact on the machine design. The collimated beam can also be used for the generation of stable femtosecond soft x-ray pulses of tunable duration from a free electron laser. S. Di Mitri et al., Phys. Rev. Special Topics - Accel. Beams 16, 042801 (2013).

MOPC07	Design Considerations for a New Beam Diagnostics for Medical Electron Accelerators	electron, diagnostics, transverse, controls	60
	D. Vlad Siemens AG Healthcare, H CP CV - Components and Vacuum, Erlangen, Germany M. Hänel Siemens Healthcare, Erlangen, Germany
	A new beam diagnostics system is under construction at the Siemens Healthcare Sector facility in Rudolstadt, Germany. The project goal is to develop, commission and operate a beam diagnostics system to characterize the compact medical linear electron accelerators and help improve the quality of their output beam. A brief system description together with the main electron beam parameters is given. The diagnostics will allow the characterization of the compact linear accelerators by measuring beam intensity/charge using a toroid, transverse beam profile using scintillating screens and transverse beam emittance by means of the quadrupole scan method. In the longitudinal plane the energy and energy spread will be determined using a spectrometer magnet.

MOPF02	The Wire Scanner Control Sytem for C-ADS Injector-II	controls, feedback, linac, diagnostics	197
	M. Li, X.C. Kang, R.S. Mao, J.X. Wu, Y.J. Yuan, J. Zhang, Y. Zhang, G. Zhu IMP, Lanzhou, People's Republic of China
	The C-ADS project is a strategic plan to solve the nuclear waste problem and the resource problem for nuclear power plants in China. The first step of this project is to build two 5-MeV test CW linac. The institute of Modern physics (IMP) is in charge of designing one of them. In order to measure the beam profile in this linac, a wire scanner system was designed and tested. In this paper, the mechanical design and control system of this wire scanner system are introduced. A real-time, closed loop control system is being developed and tested for more repeatable and accurate positioning of beam sense wires. All of the electronic and computational duties are handled in one the National Instruments compact RIO real-time chassis with a Field-Programmable Gate Array (FPGA). The beam test result of this system in IMP 320 KV beam line was present. The test result of this system and the measured beam profile result are discussed in this paper.

MOPF22	The Effect of Space Charge Along the Tomography Section at PITZ	space-charge, PITZ, transverse, simulation	255
	G. Kourkafas, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, M. Otevřel, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria
	The Photo Injector Test facility at DESY, Zeuthen site (PITZ) focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. Among various diagnostic tools installed at PITZ, the tomography module is used to reconstruct the transverse phase-space distribution of the electron beam by capturing its projections while rotating in the normalized phase space. This technique can resolve the two transverse planes simultaneously with an improved signal-to-noise ratio, allowing measurements of individual bunches within a bunch train with kicker magnets. The low emittance, high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which induce mismatches to the reconstruction procedure. This study investigates how the phase-space transformations and thus the reconstruction result are affected when considering linear and non-linear self-fields along the tomography section for the design Twiss parameters. The described analysis proposes a preliminary approach for including the effect of space charge in the tomographic reconstruction at PITZ.
	Poster MOPF22 [1.312 MB]

TUPC01	Overview of the European Spallation Source Warm Linac Beam Instrumentation	linac, ESS, diagnostics, ion	346
	B. Cheymol, C. Böhme, I. Dolenc Kittelmann, H. Hassanzadegan, A. Jansson, T.J. Shea, L. Tchelidze ESS, Lund, Sweden
	The normal conducting front end of the European Spallation source will accelerate the beam coming for the ion source up to 90 MeV. The ESS front end will consist in an ion source, a low energy beam transport line, a radio frequency quadrupole, a medium energy beam transport line and a drift tube linac. The warm linac will be equipped with beam diagnostics to measure the beam position, the transverse and longitudinal profile as well as beam current and beam losses. This will provide efficient operation of ESS, and ensure keeping the losses at a low level. This paper gives an overview of the beam diagnostics design and their main features.

TUPC03	Commissioning and Diagnostics Development for the New Short-Pulse Injector Laser at FLASH	laser, electron, gun, SASE	353
	T. Plath, J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany H. Schlarb, S. Schreiber, B. Steffen DESY, Hamburg, Germany
	In order to extend the parameter range of FLASH towards shorter electron pulses down to a few fs SASE pulses, shorter bunches with very small charges of a few tens of picocoulombs are necessary directly at the photo injector. Therefore a new injector laser delivering pulses of 1 to 5 ps has been installed and commissioned. The influence of the laser parameters on the electron beam was studied theoretically. In this paper we discuss the required laser beam diagnostics and present measurements of critical laser and electron beam parameters.
	Poster TUPC03 [1.076 MB]

TUPC26	Beam-line Diagnostics at the Front End Test Stand (FETS), Rutherford Appleton Laboratory, Oxfordshire, UK	BPM, linac, rfq, ion-source	431
	G.E. Boorman, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, S.M. Gibson JAI, Egham, Surrey, United Kingdom R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The H⁻ ion source and beam-line at FETS will require the beam current and beam position to be continually monitored. Current transformer toroids will measure the beam current and beam position monitors (BPM) will determine the beam position. The ion source delivers pulses at a rate of 50Hz with a current up to 60mA, each pulse is 2ms long, and a 324MHz micro-bunch structure imposed by the radio frequency quadrapole (RFQ) accelerating structure. The toroid outputs will be acquired on a fast oscilloscope. The BPM design is still under consideration (shorted strip-line or button type) but the processing for both types is similar and has been designed, with simulated measurements made. Each BPM uses four pickups, at a frequency of 324MHz, which are mixed using RF electronics to an intermediate frequency of 10.125MHz. The resulting signals are then digitized at 40.500MHz and processed in an FPGA to produce the position and phase of the beam at each BPM location, with a precision of better than 100μm and 0.05rad. The measurements from the toroids and BPMs will be via EPICS servers at every pulse.
	Poster TUPC26 [0.660 MB]

TUPF01	Proton Emittance Measurements in the Brookhaven AGS	AGS, IPM, injection, space-charge	492
	H. Huang, R. Connolly, C.W. Dawson, D.M. Gassner, C.E. Harper, S.E. Jao, W. Meng, F. Méot, R.J. Michnoff, M.G. Minty, V. Schoefer, T. Summers, S. Tepikian, K. Yip, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle and a multi-wire at injection. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. In addition, helical superconducting snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need TBT measurements near injection and beta function measurements at the location of devices used to measure the emittance. A Polarimeter target has been used as flying wire for proton emittance measurement. A new type electron collecting IPM has been installed and tested in the AGS with proton beam. The Beta functions at the IPM locations have been measured with Orbit Response Matrix (ORM) methods and with a local corrector at IPM. This paper summarizes our current understanding of AGS emittances and plans for further improvements.

TUPF05	Particle Tracking for the FETS Laser Wire Emittance Scanner	laser, dipole, simulation, diagnostics	503
	J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H⁻ ion beam. The diagnostics of high power particle beams is difficult due to the power deposition on diagnostics elements introduced in the beam so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process utilizing the neutralized particles produced in the interaction between Laser and H⁻ beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.

TUPF09	Commissioning Experience and First Results From the New SLS Beam Size Monitor	SLS, polarization, alignment, optics	519
	V. Schlott, M. Rohrer, A. Saá Hernández, A. Streun PSI, Villigen PSI, Switzerland Å. Andersson, J. Breunlin MAX-lab, Lund, Sweden N. Milas LNLS, Campinas, Brazil
	Funding: The presented work has received funding from the European Commission under FP-7-INFRASTRUCTURES-2010-1/INFRA-2010- 2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905. In the context of the TIARA work package “SLS vertical emittance tuning” (SVET), an extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, was verified using an optical monitor based on imaging of pi-polarized light. Since the existing beam size monitor reached its limit of resolution, a new monitor beam line was designed and installed at the 08BD bending magnet of the storage ring of the Swiss Light Source SLS. Larger magnification and operation at shorter wavelength provide improved spatial resolution. Reflective optics enables convenient switching between different wavelengths. An optical table is located in a hutch outside the storage ring tunnel to provide access during operation. Movable obstacles in the beam path create interference patterns and thus provide redundancy of model based analysis of the images. In this paper we report on our commissioning experience and provide a comparison of the different measurement methods at different wavelengths.
	Poster TUPF09 [0.292 MB]

TUPF10	A Non-Intercepting Beam Emittance Measurement Device Based on Neutral Beam Fluorescence Method at PKU	ion, ion-source, transverse, dipole	522
	S.X. Peng, J. Chen, Z.Y. Guo, H.T. Ren, Y. Xu, J. Zhao PKU, Beijing, People's Republic of China J.E. Chen, A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China L.T. Sun, H.W. Zhao IMP, Lanzhou, People's Republic of China
	A new concept to attain ion beam emmitance through measuring the forward neutral beam without intercepting the beam transportion was proposed at PKU. The forward neutral beam produced by space charge compensation and separated from the transporting ion beam with the help of a deflecting magnetic field, carries the entire emittance information of the original particle beam and becomes a fast and non-interceptive beam diagnostic tool. This idea was tested on PKU ion source test bench and the experimental results show that the neutral beam fluorescence method is feasible. Bases on these qualification results, a formal non-intercepting emittance measurement device was designed. It is a 90 degree full-scale dipole analysis magnet combining with the classical pepper-pot technique. Test and commissioning of the device are in progress. Details of design and comnissioning results will be presented in this paper.

TUPF14	Description of Laser Transport and Delivery System for the FETS Laserwire Emittance Scanner	laser, coupling, diagnostics, focusing	527
	A. Bosco, G.E. Boorman, S. Emery, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	A beam emittance monitor for H⁻ beams based on laser-induced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). The laser system that will be used for the photo-neutralization of the H⁻ beam is a fiber laser emitting 110 ns pulses at λ=1064nm, with a repetition rate of 30 kHz and peak power of 8 kW. The laser will be conveyed to the interaction area over a distance of 70 m via an optical fiber. An assembly of two remotely controlled motorized translation stages will enable the system to scan across the H⁻ beam along its vertical profile. A motorized beam expander will control the output size of the collimated laser beam in order to enable the system to operate with different spatial characteristics of the ions beam. In this paper we present a full account of the laser characteristics, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber transport efficiency and final delivery laser beam parameters will be reported.
	Poster TUPF14 [4.081 MB]

TUPF15	Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators	laser, linac, ion, CERN	531
	S.M. Gibson, G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.
	Poster TUPF15 [9.196 MB]

TUPF17	Phase Space Measurement using X-ray Pinhole Camera at SSRF	storage-ring, photon, quadrupole, radiation	539
	K.R. Ye, J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, L.Y. Yu, W.M. Zhou SINAP, Shanghai, People's Republic of China
	Since 2009 an X-ray pinhole camera that has been used to present the transverse beam size on diagnostic beamline of the storage ring in Shanghai Synchrotron Radiation Facility (SSRF). Transverse beam profiles in the real(x,y) and phase(Y,Y’) spaces are obtained by an X-ray pinhole camera sensitive by moving one pinhole. The large amount of collected data has allowed a detailed reconstruction of the transverse phase space evolution in this paper. An image on a fluorescent screen is observed by a CCD camera，digitized and stored, then the phase space and the real space profiles are reconstructed．A non-linear least square program fits the resultant profiles to a vertical dimensional Gaussian distributions to derive the phase space and emittances for SSRF storage ring．

TUPF18	Vertical Undulator Emittance Measurement: A Statistical Approach	undulator, photon, electron, radiation	543
	K.P. Wootton, R.P. Rassool The University of Melbourne, Melbourne, Australia M.J. Boland, B.C.C. Cowie, R.T. Dowd SLSA, Clayton, Australia
	Direct measurement of low vertical emittance in storage rings is typically achieved via interferometric techniques. Proof of low vertical emittance is demonstrated by the measurement of a null radiation field, which is also the crux of the vertical undulator emittance measurement. Here we present strategies to improve the sensitivity to low vertical emittance beams. We move away from photon spectrum analysis to a statistical analysis of undulator radiation, showing the measured increase in signal-to-background. Reproducing simulations of previous work, we demonstrate that photon beam polarisation extends the linearity of the technique by several decades in emittance. These statistical and polarisation improvements to the signal-to-background allow realistic measurement of smallest vertical emittance.
	Poster TUPF18 [2.090 MB]

TUPF19	APPLE-II Undulator Magnetic Fields Characterised from Undulator Radiation	undulator, radiation, photon, insertion	546
	K.P. Wootton, R.P. Rassool The University of Melbourne, Melbourne, Australia M.J. Boland, B.C.C. Cowie SLSA, Clayton, Australia
	The spatial profile of APPLE-II undulator radiation has been measured at high undulator deflection parameter, high harmonic and very small emittance. Undulators are typically designed to operate with small deflection parameter to push the fundamental mode to high photon energies. This unusual choice of parameters is desirable for measurement of vertical emittance with a vertical undulator. We present 1-D and 2-D measured profiles of undulator radiation, and show that this is reproduced in numerical models using the measured magnetic field of the insertion device. Importantly these measurements confirm that for these parameters, the spatial intensity distribution departs significantly from usual Gaussian approximations, instead resembling a double-slit diffraction pattern. This could be an important consideration for photon beamlines of ultimate storage ring light sources.
	Poster TUPF19 [2.364 MB]

TUPF20	Low Noise and High Dynamic Range Optical Interferometer Beamsize Measurements	coupling, synchrotron, storage-ring, background	550
	M.J. Boland SLSA, Clayton, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	The technique of optical interferometry to measure beam sizes requires a low noise and high dynamic range digitisation system to push the performance to ultra low emittance on storage rings. The next generation of camera sensor Scientific CMOS (sCMOS) promises to provide the technology to improve optical interferometry. A series of measurements was performed on the Australian Synchrotron storage ring using a sCMOS and a intensity imbalance optical interferometer. The coupling in the storage ring was varied from maximum to minimum using the skew quadrupoles and the beam size at the optical diagnostic beamline was varied from over 100 microns to around 1 micron. A comparison is made between interferometer measurements using the sCMOS with and without an intensity imbalance and with previous measurements using a CCD system.

TUPF24	Instrumentation for the Proposed Low Energy RHIC Electron Cooling Project	electron, ion, RHIC, diagnostics	561
	D.M. Gassner, A.V. Fedotov, D. Kayran, V. Litvinenko, R.J. Michnoff, T.A. Miller, M.G. Minty, I. Pinayev, M. Wilinski BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy There is a strong interest in running RHIC at low ion beam energies of 2.5-20GeV/nucleon; this is much lower than the typical operations with 100GeV/nucleon. The primary motivation for this effort is to explore the existence and location of the critical point on the QCD phase diagram. Electron cooling can increase the average integrated luminosity and increase the length of the stored lifetime. Simulations and conceptual cooling sub-system designs are underway. The present plan is to provide 10–50mA of bunched electron beam with adequate quality and an energy range of 0.9–5MeV. The preliminary cooling facility configuration planned to be fully inside the RHIC tunnel will include a 102.74MHz SRF gun, a booster cavity, a beam transport to the Blue ring to allow electron-ion co-propagation for ~10-20m, then a 180 degree u-turn electron transport so the same electron beam can similarly cool the Yellow ion beam, then to a dump. The electron beam instrumentation systems that will be described include current transformers, BPMs, profile monitors, a pepper pot emittance station and loss monitors.
	Poster TUPF24 [1.588 MB]

WEAL1	Large Aperture X-ray Monitors for Beam Profile Diagnostics	optics, photon, undulator, diagnostics	608
	C.A. Thomas, G. Rehm Diamond, Oxfordshire, United Kingdom F. Ewald ESRF, Grenoble, France J.W. Flanagan KEK, Ibaraki, Japan
	Emittance is one of the main characteristic properties of a beam of particles in an accelerator, and it is measured generally by means of the particle beam profile. In particular, when the beam of particles is emitting an X-ray photon beam, a non perturbative way of measuring the particle beam profile is to image it using the emitted X-ray photon beam. Over the years, numerous X-ray imaging methods have been developed, fulfilling the requirements imposed by a particle beam becoming smaller, and approaching micron size for electron beam machine with vertical emittance of the order of 1pm-rad. In this paper, we will first recall the properties of the X-ray photon as function of source and its properties. From this we will derive some natural definition of a large aperture X-ray imaging system. We will then use this selection criterion to select a number of X-ray imaging devices used as a beam profile diagnostics in an attempt to give an overview of what has been achieved and what is possible to achieve with the selected devices.
	Slides WEAL1 [7.499 MB]

WEBL3	Wake Field Monitors in a Multi Purpose X Band Accelerating Structure	alignment, CERN, dipole, longitudinal	634
	M.M. Dehler, S. Bettoni, B. Beutner, G. De Michele PSI, Villigen PSI, Switzerland G. De Michele EPFL, Lausanne, Switzerland G. De Michele CERN, Geneva, Switzerland
	In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. These feature integrated wake field monitors (WFMs), which are used to measure the alignment (offset and tilt) between structure and beam. One structure has recently been installed in the SwissFEL Injector Test facility (SITF) at PSI. The WFM front end electronics will be developed within the EuCard2 framework, so for the measurements described in this paper we used the raw WFM signals. We compare these measurements to the theoretical results obtained via an equivalent circuit model used in the design and numerical calculations. The beam tests show that by minimizing the WFM signals, the emittance dilution given by the transverse wakes, crucial because of the small aperture of the structure, is minimized as well.
	Slides WEBL3 [1.668 MB]

WEPC07	Development of the RF Front End Electronics for the SIRIUS BPM System	BPM, controls, coupling, electron	670
	R.A. Baron, F.H. Cardoso, S.R. Marques, J.L.B. Neto LNLS, Campinas, Brazil J.-C. Denard SOLEIL, Gif-sur-Yvette, France
	Tight stability requirements for new low emittance light sources, such as SIRIUS being built in Brazil, strongly depend on the BPM RF Front-End performance. Small nonlinearities, uneven temperature drifts and excess noise can spoil the performance of the whole digital BPM system and orbit correction. Calibration and temperature control schemes have been tested in order to suppress position measurement drifts during user beam delivery down to a fraction of micrometer. A method for measuring electronic component nonlinearities at mdB scale is also presented.
	Poster WEPC07 [1.236 MB]

WEPF09	Profile and Emittance Measurements at the CERN LINAC-4 3 MeV Test Stand	linac, transverse, rfq, CERN	826
	F. Zocca, E. Bravin, M. Duraffourg, G.J. Focker, D. Gerard, U. Raich, F. Roncarolo CERN, Geneva, Switzerland
	A new 160 MeV H⁻ Linac named Linac-4 will be built at CERN to replace the old 50 MeV proton Linac. The ion source, the 3 MeV RFQ and the medium energy transport (MEBT) hosting a chopper, have been commissioned in a dedicated test stand. Wire grids and wire scanners were used to measure the transverse beam profile and a slit/grid emittance meter was installed on a temporary test bench plugged at the RFQ and MEBT exit in different stages. The emittance meter slit was also used as a scanning scraper able to reconstruct the transverse profile by measuring the transmission with a downstream current transformer. On the same measurement bench, a spectrometer in conjunction with a wire grid allowed measuring the energy spread of the particles. This paper summarizes the measurement results that allowed characterizing the 3 MeV beam and discusses the present understanding of monitor performance.

WEPF11	Emittance Measurement Using X-Ray Lenses at the ESRF	electron, photon, dipole, lattice	833
	F. Ewald, J.C. Biasci, L. Farvacque, K.B. Scheidt ESRF, Grenoble, France
	During the year 2011, X-ray lenses were tested as an alternative way of emittance measurement in the ESRF storage ring. Following these tests it was decided to install a new bending magnet diagnostics beam port dedicated primarily to a permanent emittance measurement using X-ray lens imaging. The new beam port is equipped with a thin (0.6 mm) double CVD diamond window instead of 3 mm aluminium used at the pinhole beam ports. This increases the X-ray transmission, especially at low energies. The imaging and emittance measurement using aluminium lenses is discussed in comparison to the emittance measurement based on pinhole imaging. Although the principle works correctly, the setup presents different practical difficulties, such as low signal intensity and heat load.

WEPF12	Characterisation of Al-Compound Refractive Lenses for X-Rays	ESRF, LEFT, photon, dipole	837
	F. Ewald, J.C. Biasci ESRF, Grenoble, France
	We report on measurements of the surface quality (shape) of aluminium compound refractive lenses using a thin collimated X-ray beam from one of our bending magnet diagnostics beam ports. Two types of lenses were tested for overall radius of curvature, surface quality and thickness: commercially available lenses (RWTH Aachen), and lenses of the same type manufactured at the ESRF. The different surface qualities can be readily discerned with our relatively simple setup. While the technique should be improved for more precise results, it already shows clearly the imperfect surface structure of the ESRF lenses. The image quality of the beam, however, is not affected to a visible extent in our emittance measurement setup at vertical emittances of typically ~ 6 pm.

WEPF22	Non Invasive Optical Synchrotron Radiation Monitor Using a Mini-Chicane	electron, radiation, diagnostics, space-charge	860
	R.B. Fiorito, R.A. Kishek, A.G. Shkvarunets UMD, College Park, Maryland, USA D. Castronovo, M. Cornacchia, S. Di Mitri, M. Veronese Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy C. Tschalär MIT, Middleton, Massachusetts, USA
	Funding: Office of Naval Research and DOD Joint Technology Office We are developing a design for a minimally perturbing mini-chicane which utilizes the optical synchrotron radiation (OSR) generated from magnetic bends to measure the rms emittance and other optical parameters of the beam. The beam is first externally focused at the first bend and the OSR generated there is used to image the beam. Subsequently, any pair of bends produces interferences (OSRI) whose visibility can used to determine the beam divergence. The properties of different configuration of bends in the chicane have been analyzed to provide an optimum diagnostic design for a given set of beam parameters which: 1) provides a sufficient number of OSRI fringes to allow a measurement of the beam divergence; 2) minimizes the competing effect of energy spread on the fringe visibility; 3) minimizes the effect of coherent synchrotron radiation and space charge on the beam emittance; and 4) minimizes the effect of compression on the bunch length, as the beam passes through the chicane. Diagnostic designs have been produced for 100-300 MeV beams with a normalized rms emittance of about 1 micron for application to Fermi@Elettra and similar high brightness free electron lasers.
	Poster WEPF22 [0.642 MB]

Paper

Title

Other Keywords

Page

MOCL1

Beam Instrumentation at the Accelerator Test Facility 2

laser, electron, OTR, feedback

26

S.T. Boogert
JAI, Egham, Surrey, United Kingdom
S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom

The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. Four OTR (Optical Transition Radiation) monitors have been installed at the ATF2. Major characteristics is the fast measurement of projected (2D) and intrinsic (4D) emittances and the coupling corrections with skew quadrupole magnets at the upstream. The high resolution cavity beam position monitor (BPM) system is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.426 GHz, and S-band at 2.888 GHz with an increased beam aperture. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1 μm for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm. A laser-wire transverse electron beam size measurement system has been constructed and operated at the ATF2 beam line at KEK. A special set of electron beam optics was developed to generate an approximately 1μm vertical focus at the laser-wire location. Systematic measurements of a micron beam size have been successfully executed.

Slides MOCL1 [6.059 MB]

MOCL3

Emittance and Momentum Diagnostics for Beams with Large Momentum Spread

quadrupole, CLIC, diagnostics, transverse

37

M. Olvegård, V.G. Ziemann
Uppsala University, Uppsala, Sweden

In the drive beam complex of CLIC, but also in plasma wakefield accelerators, the momentum spread can be on the order of tens of percent while conventional diagnostic methods often assume a very small momentum spread. This leads to systematic misinterpretations of the measurements. Spectrometry and emittance measurements based on quadrupole scan rely on measuring the beam size, which depends on the beam envelope. This, in turn, depends on the momentum distribution. We have studied the systematic errors that arise and developed novel algorithms to correctly analyze these measurements for arbitrary momentum distributions. As an application we consider the CLIC drive beam decelerator, where extraction of up to 90% of the kinetic energy leads to a very large momentum spread. We study a measurement of the time-resolved momentum distribution, based on sweeping the beam in a circular pattern and recording the beam size on a screen using optical transition radiation. We present the algorithm to extract the time-resolved momentum distribution, together with simulation results to prove its applicability.

Slides MOCL3 [2.984 MB]

MOPC03

Overview of the ESS-Bilbao Mobile Diagnostics Test Stand

ESS, rfq, diagnostics, transverse

45

D. Belver, I. Arredondo, I. Bustinduy, P. Echevarria, J. Feuchtwanger, Z. Izaola, J. Ortega Mintegui, S. Varnasseri
ESS Bilbao, Zamudio, Spain

A MObile diagnostics Test Stand (MOTS) is being designed at ESS-Bilbao in order to characterize the beam at the end of the Radio Frequency Quadrupole (RFQ) at 3 MeV. Injection of the beam from the RFQ to the Drift Tube Linac (DTL) tank and acceleration up to 12 MeV is a sensitive operation in the accelerating chain. The output beam of the RFQ should be fully characterized and tuned to optimize this operation. To perform this characterization the MOTS is being designed with a set of diagnostics devices to measure also beam parameters after the Medium Energy Beam Transport (MEBT), and with minor modifications after the first tank of the DTL. The most important beam parameters that will be measured with the test stand are the beam current, the beam energy and the energy spread. Other important parameters are the beam emittance, the transverse beam position and the profile and bunch length. This contribution describes the beam properties that will be measured and the corresponding instrumentation devices, and presents a general layout of the MOTS.

Poster MOPC03 [1.146 MB]

MOPC04

Electron Beam Collimation for Slice Diagnostics and Generation of Femtosecond Soft X-Ray Pulses from a Free Electron Laser

electron, diagnostics, collimation, FEL

49

S. Di Mitri, M. Bossi, D. Castronovo, I. Cudin, M. Ferianis, L. Fröhlich
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

We present the experimental results of femtosecond slicing an ultra-relativistic, high brightness electron beam with a collimator*. We demonstrate that the collimation process preserves the slice beam quality, in agreement with our theoretical expectations, and that the collimation is compatible with the operation of a linear accelerator. Thus, it turns out to be a more compact and cheaper solution for electron slice diagnostics than commonly used radiofrequency deflecting cavities and having minimal impact on the machine design. The collimated beam can also be used for the generation of stable femtosecond soft x-ray pulses of tunable duration from a free electron laser.
* S. Di Mitri et al., Phys. Rev. Special Topics - Accel. Beams 16, 042801 (2013).

MOPC07

Design Considerations for a New Beam Diagnostics for Medical Electron Accelerators

electron, diagnostics, transverse, controls

60

D. Vlad
Siemens AG Healthcare, H CP CV - Components and Vacuum, Erlangen, Germany
M. Hänel
Siemens Healthcare, Erlangen, Germany

A new beam diagnostics system is under construction at the Siemens Healthcare Sector facility in Rudolstadt, Germany. The project goal is to develop, commission and operate a beam diagnostics system to characterize the compact medical linear electron accelerators and help improve the quality of their output beam. A brief system description together with the main electron beam parameters is given. The diagnostics will allow the characterization of the compact linear accelerators by measuring beam intensity/charge using a toroid, transverse beam profile using scintillating screens and transverse beam emittance by means of the quadrupole scan method. In the longitudinal plane the energy and energy spread will be determined using a spectrometer magnet.

MOPF02

The Wire Scanner Control Sytem for C-ADS Injector-II

controls, feedback, linac, diagnostics

197

M. Li, X.C. Kang, R.S. Mao, J.X. Wu, Y.J. Yuan, J. Zhang, Y. Zhang, G. Zhu
IMP, Lanzhou, People's Republic of China

The C-ADS project is a strategic plan to solve the nuclear waste problem and the resource problem for nuclear power plants in China. The first step of this project is to build two 5-MeV test CW linac. The institute of Modern physics (IMP) is in charge of designing one of them. In order to measure the beam profile in this linac, a wire scanner system was designed and tested. In this paper, the mechanical design and control system of this wire scanner system are introduced. A real-time, closed loop control system is being developed and tested for more repeatable and accurate positioning of beam sense wires. All of the electronic and computational duties are handled in one the National Instruments compact RIO real-time chassis with a Field-Programmable Gate Array (FPGA). The beam test result of this system in IMP 320 KV beam line was present. The test result of this system and the measured beam profile result are discussed in this paper.

MOPF22

The Effect of Space Charge Along the Tomography Section at PITZ

space-charge, PITZ, transverse, simulation

255

G. Kourkafas, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, M. Otevřel, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria

The Photo Injector Test facility at DESY, Zeuthen site (PITZ) focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. Among various diagnostic tools installed at PITZ, the tomography module is used to reconstruct the transverse phase-space distribution of the electron beam by capturing its projections while rotating in the normalized phase space. This technique can resolve the two transverse planes simultaneously with an improved signal-to-noise ratio, allowing measurements of individual bunches within a bunch train with kicker magnets. The low emittance, high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which induce mismatches to the reconstruction procedure. This study investigates how the phase-space transformations and thus the reconstruction result are affected when considering linear and non-linear self-fields along the tomography section for the design Twiss parameters. The described analysis proposes a preliminary approach for including the effect of space charge in the tomographic reconstruction at PITZ.

Poster MOPF22 [1.312 MB]

TUPC01

Overview of the European Spallation Source Warm Linac Beam Instrumentation

linac, ESS, diagnostics, ion

346

B. Cheymol, C. Böhme, I. Dolenc Kittelmann, H. Hassanzadegan, A. Jansson, T.J. Shea, L. Tchelidze
ESS, Lund, Sweden

The normal conducting front end of the European Spallation source will accelerate the beam coming for the ion source up to 90 MeV. The ESS front end will consist in an ion source, a low energy beam transport line, a radio frequency quadrupole, a medium energy beam transport line and a drift tube linac. The warm linac will be equipped with beam diagnostics to measure the beam position, the transverse and longitudinal profile as well as beam current and beam losses. This will provide efficient operation of ESS, and ensure keeping the losses at a low level. This paper gives an overview of the beam diagnostics design and their main features.

TUPC03

Commissioning and Diagnostics Development for the New Short-Pulse Injector Laser at FLASH

laser, electron, gun, SASE

353

T. Plath, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
H. Schlarb, S. Schreiber, B. Steffen
DESY, Hamburg, Germany

In order to extend the parameter range of FLASH towards shorter electron pulses down to a few fs SASE pulses, shorter bunches with very small charges of a few tens of picocoulombs are necessary directly at the photo injector. Therefore a new injector laser delivering pulses of 1 to 5 ps has been installed and commissioned. The influence of the laser parameters on the electron beam was studied theoretically. In this paper we discuss the required laser beam diagnostics and present measurements of critical laser and electron beam parameters.

Poster TUPC03 [1.076 MB]

TUPC26

Beam-line Diagnostics at the Front End Test Stand (FETS), Rutherford Appleton Laboratory, Oxfordshire, UK

BPM, linac, rfq, ion-source

431

G.E. Boorman, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The H⁻ ion source and beam-line at FETS will require the beam current and beam position to be continually monitored. Current transformer toroids will measure the beam current and beam position monitors (BPM) will determine the beam position. The ion source delivers pulses at a rate of 50Hz with a current up to 60mA, each pulse is 2ms long, and a 324MHz micro-bunch structure imposed by the radio frequency quadrapole (RFQ) accelerating structure. The toroid outputs will be acquired on a fast oscilloscope. The BPM design is still under consideration (shorted strip-line or button type) but the processing for both types is similar and has been designed, with simulated measurements made. Each BPM uses four pickups, at a frequency of 324MHz, which are mixed using RF electronics to an intermediate frequency of 10.125MHz. The resulting signals are then digitized at 40.500MHz and processed in an FPGA to produce the position and phase of the beam at each BPM location, with a precision of better than 100μm and 0.05rad. The measurements from the toroids and BPMs will be via EPICS servers at every pulse.

Poster TUPC26 [0.660 MB]

TUPF01

Proton Emittance Measurements in the Brookhaven AGS

AGS, IPM, injection, space-charge

492

H. Huang, R. Connolly, C.W. Dawson, D.M. Gassner, C.E. Harper, S.E. Jao, W. Meng, F. Méot, R.J. Michnoff, M.G. Minty, V. Schoefer, T. Summers, S. Tepikian, K. Yip, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle and a multi-wire at injection. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. In addition, helical superconducting snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need TBT measurements near injection and beta function measurements at the location of devices used to measure the emittance. A Polarimeter target has been used as flying wire for proton emittance measurement. A new type electron collecting IPM has been installed and tested in the AGS with proton beam. The Beta functions at the IPM locations have been measured with Orbit Response Matrix (ORM) methods and with a local corrector at IPM. This paper summarizes our current understanding of AGS emittances and plans for further improvements.

TUPF05

Particle Tracking for the FETS Laser Wire Emittance Scanner

laser, dipole, simulation, diagnostics

503

J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H⁻ ion beam. The diagnostics of high power particle beams is difficult due to the power deposition on diagnostics elements introduced in the beam so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process utilizing the neutralized particles produced in the interaction between Laser and H⁻ beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.

TUPF09

Commissioning Experience and First Results From the New SLS Beam Size Monitor

SLS, polarization, alignment, optics

519

V. Schlott, M. Rohrer, A. Saá Hernández, A. Streun
PSI, Villigen PSI, Switzerland
Å. Andersson, J. Breunlin
MAX-lab, Lund, Sweden
N. Milas
LNLS, Campinas, Brazil

Funding: The presented work has received funding from the European Commission under FP-7-INFRASTRUCTURES-2010-1/INFRA-2010- 2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
In the context of the TIARA work package “SLS vertical emittance tuning” (SVET), an extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, was verified using an optical monitor based on imaging of pi-polarized light. Since the existing beam size monitor reached its limit of resolution, a new monitor beam line was designed and installed at the 08BD bending magnet of the storage ring of the Swiss Light Source SLS. Larger magnification and operation at shorter wavelength provide improved spatial resolution. Reflective optics enables convenient switching between different wavelengths. An optical table is located in a hutch outside the storage ring tunnel to provide access during operation. Movable obstacles in the beam path create interference patterns and thus provide redundancy of model based analysis of the images. In this paper we report on our commissioning experience and provide a comparison of the different measurement methods at different wavelengths.

Poster TUPF09 [0.292 MB]

TUPF10

A Non-Intercepting Beam Emittance Measurement Device Based on Neutral Beam Fluorescence Method at PKU

ion, ion-source, transverse, dipole

522

S.X. Peng, J. Chen, Z.Y. Guo, H.T. Ren, Y. Xu, J. Zhao
PKU, Beijing, People's Republic of China
J.E. Chen, A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
L.T. Sun, H.W. Zhao
IMP, Lanzhou, People's Republic of China

A new concept to attain ion beam emmitance through measuring the forward neutral beam without intercepting the beam transportion was proposed at PKU. The forward neutral beam produced by space charge compensation and separated from the transporting ion beam with the help of a deflecting magnetic field, carries the entire emittance information of the original particle beam and becomes a fast and non-interceptive beam diagnostic tool. This idea was tested on PKU ion source test bench and the experimental results show that the neutral beam fluorescence method is feasible. Bases on these qualification results, a formal non-intercepting emittance measurement device was designed. It is a 90 degree full-scale dipole analysis magnet combining with the classical pepper-pot technique. Test and commissioning of the device are in progress. Details of design and comnissioning results will be presented in this paper.

TUPF14

Description of Laser Transport and Delivery System for the FETS Laserwire Emittance Scanner

laser, coupling, diagnostics, focusing

527

A. Bosco, G.E. Boorman, S. Emery, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A beam emittance monitor for H⁻ beams based on laser-induced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). The laser system that will be used for the photo-neutralization of the H⁻ beam is a fiber laser emitting 110 ns pulses at λ=1064nm, with a repetition rate of 30 kHz and peak power of 8 kW. The laser will be conveyed to the interaction area over a distance of 70 m via an optical fiber. An assembly of two remotely controlled motorized translation stages will enable the system to scan across the H⁻ beam along its vertical profile. A motorized beam expander will control the output size of the collimated laser beam in order to enable the system to operate with different spatial characteristics of the ions beam. In this paper we present a full account of the laser characteristics, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber transport efficiency and final delivery laser beam parameters will be reported.

Poster TUPF14 [4.081 MB]

TUPF15

Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators

laser, linac, ion, CERN

531

S.M. Gibson, G.E. Boorman, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.

Poster TUPF15 [9.196 MB]

TUPF17

Phase Space Measurement using X-ray Pinhole Camera at SSRF

storage-ring, photon, quadrupole, radiation

539

K.R. Ye, J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, L.Y. Yu, W.M. Zhou
SINAP, Shanghai, People's Republic of China

Since 2009 an X-ray pinhole camera that has been used to present the transverse beam size on diagnostic beamline of the storage ring in Shanghai Synchrotron Radiation Facility (SSRF). Transverse beam profiles in the real(x,y) and phase(Y,Y’) spaces are obtained by an X-ray pinhole camera sensitive by moving one pinhole. The large amount of collected data has allowed a detailed reconstruction of the transverse phase space evolution in this paper. An image on a fluorescent screen is observed by a CCD camera，digitized and stored, then the phase space and the real space profiles are reconstructed．A non-linear least square program fits the resultant profiles to a vertical dimensional Gaussian distributions to derive the phase space and emittances for SSRF storage ring．

TUPF18

Vertical Undulator Emittance Measurement: A Statistical Approach

undulator, photon, electron, radiation

543

K.P. Wootton, R.P. Rassool
The University of Melbourne, Melbourne, Australia
M.J. Boland, B.C.C. Cowie, R.T. Dowd
SLSA, Clayton, Australia

Direct measurement of low vertical emittance in storage rings is typically achieved via interferometric techniques. Proof of low vertical emittance is demonstrated by the measurement of a null radiation field, which is also the crux of the vertical undulator emittance measurement. Here we present strategies to improve the sensitivity to low vertical emittance beams. We move away from photon spectrum analysis to a statistical analysis of undulator radiation, showing the measured increase in signal-to-background. Reproducing simulations of previous work, we demonstrate that photon beam polarisation extends the linearity of the technique by several decades in emittance. These statistical and polarisation improvements to the signal-to-background allow realistic measurement of smallest vertical emittance.

Poster TUPF18 [2.090 MB]

TUPF19

APPLE-II Undulator Magnetic Fields Characterised from Undulator Radiation

undulator, radiation, photon, insertion

546

K.P. Wootton, R.P. Rassool
The University of Melbourne, Melbourne, Australia
M.J. Boland, B.C.C. Cowie
SLSA, Clayton, Australia

The spatial profile of APPLE-II undulator radiation has been measured at high undulator deflection parameter, high harmonic and very small emittance. Undulators are typically designed to operate with small deflection parameter to push the fundamental mode to high photon energies. This unusual choice of parameters is desirable for measurement of vertical emittance with a vertical undulator. We present 1-D and 2-D measured profiles of undulator radiation, and show that this is reproduced in numerical models using the measured magnetic field of the insertion device. Importantly these measurements confirm that for these parameters, the spatial intensity distribution departs significantly from usual Gaussian approximations, instead resembling a double-slit diffraction pattern. This could be an important consideration for photon beamlines of ultimate storage ring light sources.

Poster TUPF19 [2.364 MB]

TUPF20

Low Noise and High Dynamic Range Optical Interferometer Beamsize Measurements

coupling, synchrotron, storage-ring, background

550

M.J. Boland
SLSA, Clayton, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

The technique of optical interferometry to measure beam sizes requires a low noise and high dynamic range digitisation system to push the performance to ultra low emittance on storage rings. The next generation of camera sensor Scientific CMOS (sCMOS) promises to provide the technology to improve optical interferometry. A series of measurements was performed on the Australian Synchrotron storage ring using a sCMOS and a intensity imbalance optical interferometer. The coupling in the storage ring was varied from maximum to minimum using the skew quadrupoles and the beam size at the optical diagnostic beamline was varied from over 100 microns to around 1 micron. A comparison is made between interferometer measurements using the sCMOS with and without an intensity imbalance and with previous measurements using a CCD system.

TUPF24

Instrumentation for the Proposed Low Energy RHIC Electron Cooling Project

electron, ion, RHIC, diagnostics

561

D.M. Gassner, A.V. Fedotov, D. Kayran, V. Litvinenko, R.J. Michnoff, T.A. Miller, M.G. Minty, I. Pinayev, M. Wilinski
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
There is a strong interest in running RHIC at low ion beam energies of 2.5-20GeV/nucleon; this is much lower than the typical operations with 100GeV/nucleon. The primary motivation for this effort is to explore the existence and location of the critical point on the QCD phase diagram. Electron cooling can increase the average integrated luminosity and increase the length of the stored lifetime. Simulations and conceptual cooling sub-system designs are underway. The present plan is to provide 10–50mA of bunched electron beam with adequate quality and an energy range of 0.9–5MeV. The preliminary cooling facility configuration planned to be fully inside the RHIC tunnel will include a 102.74MHz SRF gun, a booster cavity, a beam transport to the Blue ring to allow electron-ion co-propagation for ~10-20m, then a 180 degree u-turn electron transport so the same electron beam can similarly cool the Yellow ion beam, then to a dump. The electron beam instrumentation systems that will be described include current transformers, BPMs, profile monitors, a pepper pot emittance station and loss monitors.

Poster TUPF24 [1.588 MB]

WEAL1

Large Aperture X-ray Monitors for Beam Profile Diagnostics

optics, photon, undulator, diagnostics

608

C.A. Thomas, G. Rehm
Diamond, Oxfordshire, United Kingdom
F. Ewald
ESRF, Grenoble, France
J.W. Flanagan
KEK, Ibaraki, Japan

Emittance is one of the main characteristic properties of a beam of particles in an accelerator, and it is measured generally by means of the particle beam profile. In particular, when the beam of particles is emitting an X-ray photon beam, a non perturbative way of measuring the particle beam profile is to image it using the emitted X-ray photon beam. Over the years, numerous X-ray imaging methods have been developed, fulfilling the requirements imposed by a particle beam becoming smaller, and approaching micron size for electron beam machine with vertical emittance of the order of 1pm-rad. In this paper, we will first recall the properties of the X-ray photon as function of source and its properties. From this we will derive some natural definition of a large aperture X-ray imaging system. We will then use this selection criterion to select a number of X-ray imaging devices used as a beam profile diagnostics in an attempt to give an overview of what has been achieved and what is possible to achieve with the selected devices.

Slides WEAL1 [7.499 MB]

WEBL3

Wake Field Monitors in a Multi Purpose X Band Accelerating Structure

alignment, CERN, dipole, longitudinal

634

M.M. Dehler, S. Bettoni, B. Beutner, G. De Michele
PSI, Villigen PSI, Switzerland
G. De Michele
EPFL, Lausanne, Switzerland
G. De Michele
CERN, Geneva, Switzerland

In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. These feature integrated wake field monitors (WFMs), which are used to measure the alignment (offset and tilt) between structure and beam. One structure has recently been installed in the SwissFEL Injector Test facility (SITF) at PSI. The WFM front end electronics will be developed within the EuCard2 framework, so for the measurements described in this paper we used the raw WFM signals. We compare these measurements to the theoretical results obtained via an equivalent circuit model used in the design and numerical calculations. The beam tests show that by minimizing the WFM signals, the emittance dilution given by the transverse wakes, crucial because of the small aperture of the structure, is minimized as well.

Slides WEBL3 [1.668 MB]

WEPC07

Development of the RF Front End Electronics for the SIRIUS BPM System

BPM, controls, coupling, electron

670

R.A. Baron, F.H. Cardoso, S.R. Marques, J.L.B. Neto
LNLS, Campinas, Brazil
J.-C. Denard
SOLEIL, Gif-sur-Yvette, France

Tight stability requirements for new low emittance light sources, such as SIRIUS being built in Brazil, strongly depend on the BPM RF Front-End performance. Small nonlinearities, uneven temperature drifts and excess noise can spoil the performance of the whole digital BPM system and orbit correction. Calibration and temperature control schemes have been tested in order to suppress position measurement drifts during user beam delivery down to a fraction of micrometer. A method for measuring electronic component nonlinearities at mdB scale is also presented.

Poster WEPC07 [1.236 MB]

WEPF09

Profile and Emittance Measurements at the CERN LINAC-4 3 MeV Test Stand

linac, transverse, rfq, CERN

826

F. Zocca, E. Bravin, M. Duraffourg, G.J. Focker, D. Gerard, U. Raich, F. Roncarolo
CERN, Geneva, Switzerland

A new 160 MeV H⁻ Linac named Linac-4 will be built at CERN to replace the old 50 MeV proton Linac. The ion source, the 3 MeV RFQ and the medium energy transport (MEBT) hosting a chopper, have been commissioned in a dedicated test stand. Wire grids and wire scanners were used to measure the transverse beam profile and a slit/grid emittance meter was installed on a temporary test bench plugged at the RFQ and MEBT exit in different stages. The emittance meter slit was also used as a scanning scraper able to reconstruct the transverse profile by measuring the transmission with a downstream current transformer. On the same measurement bench, a spectrometer in conjunction with a wire grid allowed measuring the energy spread of the particles. This paper summarizes the measurement results that allowed characterizing the 3 MeV beam and discusses the present understanding of monitor performance.

WEPF11

Emittance Measurement Using X-Ray Lenses at the ESRF

electron, photon, dipole, lattice

833

F. Ewald, J.C. Biasci, L. Farvacque, K.B. Scheidt
ESRF, Grenoble, France

During the year 2011, X-ray lenses were tested as an alternative way of emittance measurement in the ESRF storage ring. Following these tests it was decided to install a new bending magnet diagnostics beam port dedicated primarily to a permanent emittance measurement using X-ray lens imaging. The new beam port is equipped with a thin (0.6 mm) double CVD diamond window instead of 3 mm aluminium used at the pinhole beam ports. This increases the X-ray transmission, especially at low energies. The imaging and emittance measurement using aluminium lenses is discussed in comparison to the emittance measurement based on pinhole imaging. Although the principle works correctly, the setup presents different practical difficulties, such as low signal intensity and heat load.

WEPF12

Characterisation of Al-Compound Refractive Lenses for X-Rays

ESRF, LEFT, photon, dipole

837

F. Ewald, J.C. Biasci
ESRF, Grenoble, France

We report on measurements of the surface quality (shape) of aluminium compound refractive lenses using a thin collimated X-ray beam from one of our bending magnet diagnostics beam ports. Two types of lenses were tested for overall radius of curvature, surface quality and thickness: commercially available lenses (RWTH Aachen), and lenses of the same type manufactured at the ESRF. The different surface qualities can be readily discerned with our relatively simple setup. While the technique should be improved for more precise results, it already shows clearly the imperfect surface structure of the ESRF lenses. The image quality of the beam, however, is not affected to a visible extent in our emittance measurement setup at vertical emittances of typically ~ 6 pm.

WEPF22

Non Invasive Optical Synchrotron Radiation Monitor Using a Mini-Chicane

electron, radiation, diagnostics, space-charge

860

R.B. Fiorito, R.A. Kishek, A.G. Shkvarunets
UMD, College Park, Maryland, USA
D. Castronovo, M. Cornacchia, S. Di Mitri, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
C. Tschalär
MIT, Middleton, Massachusetts, USA

Funding: Office of Naval Research and DOD Joint Technology Office
We are developing a design for a minimally perturbing mini-chicane which utilizes the optical synchrotron radiation (OSR) generated from magnetic bends to measure the rms emittance and other optical parameters of the beam. The beam is first externally focused at the first bend and the OSR generated there is used to image the beam. Subsequently, any pair of bends produces interferences (OSRI) whose visibility can used to determine the beam divergence. The properties of different configuration of bends in the chicane have been analyzed to provide an optimum diagnostic design for a given set of beam parameters which: 1) provides a sufficient number of OSRI fringes to allow a measurement of the beam divergence; 2) minimizes the competing effect of energy spread on the fringe visibility; 3) minimizes the effect of coherent synchrotron radiation and space charge on the beam emittance; and 4) minimizes the effect of compression on the bunch length, as the beam passes through the chicane. Diagnostic designs have been produced for 100-300 MeV beams with a normalized rms emittance of about 1 micron for application to Fermi@Elettra and similar high brightness free electron lasers.

Poster WEPF22 [0.642 MB]