DIPAC2011 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOOB02	Emittance and Energy Spread Measurements of Relativistic Electrons From Laser-Driven Accelerator	electron, laser, plasma, brightness	9
	G.G. Manahan, M.P. Anania, C. Aniculaesei, E. Brunetti, S. Cipiccia, B. Ersfeld, M.R. Islam, R.C. Issac, D.A. Jaroszynski, R.P. Shanks, G.H. Welsh, S.M. Wiggins USTRAT/SUPA, Glasgow, United Kingdom
	Funding: Funding supported by U.K. EPSRC and the Scottish Universities Physics Alliance. In this paper, we present a single-shot transverse emittance measurement for 125 ± 3 MeV electron beam using pepper-pot technique. A normalised transverse emittance as low as 1.1 ± 0.1 π-mm-mrad was measured using this method. Considering 60 consecutive shots, an average normalised emittance of ε_rms,x,y=2.2 ± 0.7, 2.3 ± 0.6 π-mm-mrad was obtained, which is comparable to a conventional linear accelerator. We also obtained high energy monoenergetic electron beam with relative energy spread less than 1%. The measured transverse emittance characterises the quality of an electron beam generated from laser-driven accelerator. Brightness, parallelism and focusability are all functions of the emittance. The low emittance and energy spread indicates that this type of accelerator is suitable for compact free electron laser driver.
	Slides MOOB02 [7.052 MB]

MOPD06	Capabilities and Performance of the LHC Schottky Monitors	pick-up, injection, impedance, proton	44
	M. Favier, T.B. Bogey, F. Caspers, O.R. Jones CERN, Geneva, Switzerland J. Cai, E.S.M. McCrory, R.J. Pasquinelli Fermilab, Batavia, USA A. Jansson ESS, Lund, Sweden
	The LHC Schottky system has been under commissioning since summer 2010. This non destructive observation relies on a slotted waveguide structure resonating at 4.8GHz. Four monitors, one for each plane of the two counter-rotating LHC beams, are used to measure the transverse Schottky sidebands Electronic gating allows selective bunch-by-bunch measurements, while a triple down-mixing scheme combined with heavy filtering gives an instantaneous dynamic range of over 100dB within a 20kHz bandwidth. Observations of both proton and lead ion Schottky spectra will be discussed along with a comparison of predicted and measured performance.
	Poster MOPD06 [3.484 MB]

MOPD12	Expressing Properties of BPM Measurement System in Terms of Error Emittance and Error Twiss Parameters	betatron, FEL, beam-transport, focusing	62
	V. Balandin, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The determination of variations in the beam position and in the beam energy using BPM readings is one of the standard problems of accelerator physics. If the optical model of the beam line and BPM resolutions are known, the typical choice is to let jitter parameters be a solution of the weighted linear least squares problem. For transversely uncoupled motion this least squares problem can be solved analytically, but the direct usage of the obtained solution as a tool for designing a BPM measurement system is not straightforward. A better understanding of the nature of the problem is needed. In this paper we show that properties of the BPM measurement system can be described in terms of the usual accelerator physics concepts of emittance, energy spread, dispersions and betatron functions. In this way one can compare two BPM systems comparing their so-called error emittances and error energy spreads, or, for a given measurement system, one can achieve a balance between coordinate and momentum reconstruction errors by matching the error betatron functions in the point of interest to the desired values.

MOPD45	Single-Shot Beam Characterization Device Based on the Pepper-Pot Principle	ion, electron, permanent-magnet, beam-transport	155
	S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Z.X. Yuan, J. Zhao PKU/IHIP, Beijing, People's Republic of China H.T. Ren Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Funding: National Nutural Science Foundation of China No.11075008 For the characterization of an ampere-scale microsecond single-pulse ion beam, a pepper-pot based beam profile measurement device was developed in PekingUniversity(PKU). It is a combination of Faraday cup technique with pepper-pot measurement facility. The direct Faraday cup is used to observe the total beam current and an array of pepper-pot diamond holes at the bottom of the Faraday cup is served to separate a large beam into several beamlets for beam distribution measurement. A Faraday array that locates 3.8 mm away from the pepper-pot screen is used to measure the transverse size of the beam. Two sets of permanent magnet poles that locate at the entrance of the Faraday cup and just before the Faraday array respectively are used to suppressing the second electrons produced by the interaction of the beam with target. In this paper we emphasize details of the experimental setup, the results of the measurements and we give an outlook on further developments on pepper-pot devices.

MOPD49	Beam Parameters Measurements by Ionization Cross Section Monitor on Proton LINAC of INR RAS	linac, radiation, ion, proton	161
	P.I. Reinhardt-Nickoulin, S. Bragin, A. Feschenko, S.A. Gavrilov, I.V. Vasilyev, O. Volodkevich RAS/INR, Moscow, Russia
	The ionization beam cross section monitor (BCSM) is developed and used on proton linac of INR RAS to provide non-intercepting measurements of beam parameters. Operation of the monitor is based on utilization of residual gas ionization. The BCSM configuration design and image processing system are described and estimations of influence of the linac radiation background are discussed. The monitor enables to observe beam cross section and extract from it beam profiles and position as well as their evolution in time within a wide range of beam intensities and energies. The available experimental results of beam spot, profiles and emittances measurements at the linac output are presented.

MOPD52	First Results from Beam Measurements at the 3 MeV Test Stand for CERN Linac4	solenoid, linac, rfq, proton	167
	B. Cheymol, J.-B. Lallement, A.E. Lokhovitskiy, O. Midttun, U. Raich, F. Roncarolo, R. Scrivens, E. Zorin CERN, Geneva, Switzerland B. Cheymol Université Blaise Pascal, Clermont-Ferrand, France
	The H⁻ source and the low energy beam line will determine to a large extend the performance of Linac-4, the new machine foreseen as injector into the PS Booster. For this reason a test stand will be set up consisting of the source, Low Energy Beam Transport (LEBT), RFQ and chopper line. Up to now only the source and LEBT are installed. First measurements have been performed using a Faraday Cup to measure the total source intensity, a slit-&-grid emittance meter for transverse emittance measurements and a spectrometer for energy spread measurements. This paper discusses the results from measurements on H⁻ beams at 35kV extraction voltage as well as protons at 45 kV, showing the emittance dependence on source RF power as well as the influence of a solenoid in splitting the beam into its various constituents: protons, H0, H²⁺ and H³⁺. Energy spread measurements are also presented.

MOPD57	Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations	ion, linac, target, alignment	179
	E. Gütlich, P. Forck, B. Walasek-Höhne GSI, Darmstadt, Germany W. Ensinger TU Darmstadt, Darmstadt, Germany
	Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al₂O₃ with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al₂O₃ this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators.

MOPD61	Vertical Emittance Measurement at the ESRF	radiation, photon, synchrotron, dipole	188
	F. Ewald, P. Elleaume, L. Farvacque, A. Franchi, D. Robinson, K.B. Scheidt, A. Snigirev, I. Snigireva ESRF, Grenoble, France
	In the short term the ESRF aims to reach emittances of less than 2 pm. We review the existing emittance diagnostics – X-ray projection monitors and pinhole cameras – and evaluate their ability to resolve such ultra-small vertical emittances. Even though these devices are reliable and show good agreement between measurements and theoretical predictions down to vertical emittance values of less than 10 pm, they will reach their limit of resolution for emittances decreasing below a few picometers. In addition to the existing emittance diagnostics, a new device was installed that images bending magnet radiation using compound refractive lenses (CRLs).

MOPD62	Storage Ring Injector Diagnostics using Synchrotron Radiation	injection, diagnostics, radiation, booster	191
	A.F.D. Morgan, C.A. Thomas Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	The state of the Diamond injector can be passively monitored using beam profile measurements of synchrotron radiation from bending magnets. This provides us with information on the characteristics of the beam injected into the storage ring. Using a numerical fit we are able to retrieve key parameters like beam position, size and tilt angle from every shot. This enables us to gather longer term trends to monitor for any changes during top-up operation in order to better understand any variability of the injector. We present here the study and the analysis performed with this diagnostic with the results from several months of operation.
	Poster MOPD62 [0.451 MB]

MOPD69	Tune Measurements with High Intensity Beams at SIS-18	injection, acceleration, monitoring, diagnostics	206
	R. Singh, P. Forck, W. Kaufmann, P. Kowina GSI, Darmstadt, Germany R. Singh TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork), Project Number ITN-2008-215080 To achieve high current operation close to the space charge limit in a synchrotron, a precise tune measurement during a full accelerating cycle is required. A tune measurement system that was recently commissioned at GSI synchrotron SIS-18 allows for online evaluation of the actual tune. This system consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations of the beam. The BPM signals thus induced are digitized by fast ADCs at 125 MSa/s and then the post processing electronics integrates the data bunch by bunch to obtain one position value per bunch. Subsequently base band tune is determined by Fourier transformation of the position data. The tune variation during acceleration for various beam conditions was measured using this system and is discussed. A detailed investigation of the incoherent tune shift was conducted with Uranium ion beams at the injection energy of 11.6 MeV/u. The results show the influence of beam current on the tune spectrum. In addition, the effects of the measurement method on the beam emittance and beam losses are discussed.

MOPD84	Hollow Photocathode Prototype for e-Gun	laser, cathode, electron, niobium	242
	M.A. Nozdrin, N. Balalykin, A.A. Feshchenko, V. Minashkin, G. Shirkov, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia S. Gazi, J. Huran Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
	Photocathodes are important devices for contemporary electron accelerators. Significant photocathode parameters are: fast response time, quantum efficiency, long lifetime, low emittance and minimal effect on RF properties of the accelerating system. In this paper development of the hollow photocathode conception is presented and prototype is described. Such cathode geometry allows quantum efficiency rising due to surface photoelectric effect which is concerned with normal to material surface wave electric field multiplier. Experimental results of hollow photocathode using efficiency are given (266nm wavelength, 15 ns pulse time with 1 Hz repetition rate). Backside irradiation radically simplifies laser beam targeting on emitting surface, accelerator equipment adjustment and allows photocathode working surface laser cleaning.
	Poster MOPD84 [1.505 MB]

MOPD85	Beam Emittance Studies at the Heavy Ion Linac UNILAC	rfq, ion, linac, DTL	245
	P. Gerhard, W.A. Barth, L.A. Dahl, L. Groening, H. Vormann GSI, Darmstadt, Germany
	New accelerating structures for the UNILAC at GSI were commissioned in the last two years [1, 2], and major machine upgrades in order to meet the requirements for FAIR are in preparation [3, 4]. Beam emittance is one of the key beam parameters that are essential for any beam dynamics calculation, for the design of new accelerators as well as verification or investigation of existing machines. Its measurement is intricate and often time consuming. Extensive emittance measurements went along with the commissionings and were conducted to provide a reliable basis for beam dynamics simulations. In addition to the 10 permanent transverse emittance measurement devices installed all over the UNILAC, two "mobile" devices had been built and mounted at four different sites in the UNILAC. This work shows the standard slid-grid device used for transverse beam emittance measurements and gives an overview of the activities and results. The following topics will be presented with respect to design studies and simulations: Emittance growth of high current ion beams along the UNILAC, stripping, and resonance effects. [1] H. Vormann et al., LINAC10, MOP040 [2] P. Gerhard et al., IPAC10, MOPD028 [3] W. Barth et al., PAC09, FR5REP059 [4] S. Mickat et al., LINAC10, MOP042
	Poster MOPD85 [10.077 MB]

MOPD88	Electron Beam Ion Sources, Ion Optical Elements and Beam Diagnostics for Particle Accelerators	ion, electron, ion-source, injection	254
	F. Ullmann, V.P. Ovsyannikov, M. Schmidt DREEBIT GmbH, Dresden, Germany G. Zschornack Technische Universität Dresden, Institut für Angewandte Physik, Dresden, Germany
	Electron Beam Ion Sources (EBISs) provide highly charged ions (HCIs) for a variety of investigations and applications, amongst others as injection source for particle accelerators. EBISs feature a lot of advantages which qualify them for accelerator injection, and which partly compensate their comparatively low number of particles. DREEBIT GmbH provides a family of compact EBISs based on permanent magnets. A more sophisticated version is based on cryogen-free superconducting magnets providing a higher ion output. Its compact design makes them transportable, low in operational costs, and guarantee easy handling. We present latest improvements and measurements proving the feasibility of producing beams of HCIs with convenient beam properties such as low transversal and longitudinal emittance. In addition we present a variety of ion optical elements and ion beam diagnostics. The DREEBIT Wien filter allows for the charge mass separation. The DREEBIT Pepper-pot Emittance Meter allows for emittance measurements of beams of a wide range of particle intensity. Other beam diagnostics are provided, such as Beam Imaging System, Retarding Field Analyzer and different kinds of Faraday cups.

TUPD04	Diagnostics for the 150 MeV Linac and Test Transport Line of Taiwan Photon Source	linac, diagnostics, site, electron	308
	C.-Y. Liao, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo, D. Lee, K.-K. Lin, K.L. Tsai, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The TPS 150 MeV linac is in installation and commissioning phase at the test site for acceptance test. The linac will move to the final installation site after the building complete which is expected in 2012. The linac and a short transport line for main parameters measurement equips with several types of diagnostic devices, which include screen monitors, fast current transformers, integrated current transformer, wall current monitors, beam position monitors and Faraday cups. These devices are arranged to measure the specification parameters such as charge in bunch train, pulse purity, energy, energy spread, and emittance. Implementation details and preliminary test results will be summarized in this report.

TUPD07	Instrumentation Needs and Solutions for the Development of an SRF Photoelectron Injector at the Energy-Recovery Linac BERLinPro	gun, SRF, laser, cavity	317
	R. Barday, T. Kamps, A. Neumann, J. Rudolph, S.G. Schubert, J. Völker HZB, Berlin, Germany A. Ferrarotto, T. Weis DELTA, Dortmund, Germany
	BERLinPro is an energy-recovery linac for an electron beam with 1 mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. Development of this source is a major part of the BERLinPro programme. The instrumentation for the first stage of the programme serves the purpose to have robust and reliable monitors for fundamental beam parameters like emittance, bunch charge, energy and energy spread. The critical issue of the second stage is the generation of an electron beam with 100 mA average current and a normalized emittance of 1 mm mrad. Therefore we plan to setup a dedicated instrumentation beamline with a compact DC gun to measure thermal emittance, current and current lifetime. In parallel an SRF gun with dedicated diagnostics will be build focused on ERL specific aspects like emittance compensation with low-energy beams and reliability of high current operation. This paper collects requirements for each development stage and discusses solutions to specific measurement problems.

TUPD31	Measurement of the Slice Energy Spread Induced by a Transverse Deflecting RF Structure at FLASH	electron, RF-structure, FEL, free-electron-laser	371
	C. Gerth, C. Behrens DESY, Hamburg, Germany
	Operation of a high-gain free-electron laser requires a high-brightness electron beam with high peak current and small slice energy spread. The slice energy spread can be measured with high longitudinal resolution by using a transverse deflecting structure in combination with viewing screen in a dispersive section. However, off-axis accelerating fields induce a correlated energy spread that depends inversely proportional on the longitudinal resolution. As a consequence, short bunches, which intrinsically require a high longitudinal resolution in order to be diagnosed, suffer from a large induced energy spread which limits the energy resolution. To be able to measure the impact of the transverse deflecting structure on the slice energy spread without distortions by space charge or coherent synchrotron radiation effects, we tailored short electron bunches with low peak currents by clipping low energy electrons in the collimator of the first bunch compressor at FLASH. In this paper, we present first systematic measurements of the correlated energy spread induced by a transverse deflecting structure. The results are compared with analytical calculations.

TUPD50	Slice-Emittance Measurements at ELBE / SRF-Injector	electron, simulation, SRF, quadrupole	416
	J. Rudolph, M. Abo-Bakr, T. Kamps HZB, Berlin, Germany J. Teichert HZDR, Dresden, Germany
	Funding: Supported by the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, contract number 227579) The linear accelerator ELBE delivers high-brightness electron bunches to multiple user stations, including an IR-FEL. The current thermionic injector is being replaced by a superconducting rf photoinjector (SRF-injector) which promises higher beam quality. Using a transfer chicane, beam from the SRF-injector can be injected into the ELBE linac. Detailed characterization of the electron beam is achieved by measuring the vertical slice emittance of the beam. To perform this measurement a combination of rf zero-phasing, spectrometer dipole and quadrupole scan is used. The electron beam is accelerated by the first cavity of the ELBE accelerator module and send through a second cavity which is operated at zero-crossing of the rf. In doing so a linear energy-time correlation is induced to the beam. The chirped beam is send through a spectrometer dipole and the longitudinal distribution can be made visible on a scintillator screen. Performing a quadrupole scan allows the determination of the emittance for different slices. This paper explains the working principle of the method and the experimental setup and shows results of performed simulations as well as first measurement results.

TUPD56	High Resolution SR Profile Monitor at ATF2 Extraction Line	extraction, background, controls, damping	434
	T. Naito, T.M. Mitsuhashi KEK, Ibaraki, Japan
	The profile monitor using visible light of the SR at ATF2 extraction line has been developed. KEK-ATF is a facility to produce extremely low emittance beam for the linear collider. The emittance in the damping ring is ex=1x10^-9 m and ey=1x10{-11} m, respectively. The ATF2 extraction line is a transport line to study the Final focus system for the linear collider. The designed beam size at the profile monitor is 230 μm in horizontal and 13 μm in vertical. We used a wide aperture optical system to reduce the Rayleigh limit of the optical system. The performance of the monitor is reported.

TUPD60	Optical Diagnostics for Frankfurt Neutron Source	diagnostics, simulation, factory, neutron	443
	H. Reichau, O. Meusel, U. Ratzinger, C. Wagner IAP, Frankfurt am Main, Germany
	A non-interceptive optical diagnostic system on the basis of beam tomography, was developed for the planned Frankfurt Neutron Source (FRANZ). The proton driver linac of FRANZ will provide energies up to 2.0 MeV. The measurement device will non-interceptively derive required beam parameters at the end of the LEBT at beam energies of 120 keV and a current of 200 mA. On a narrow space of 351.2 mm length a rotatable tomography tank will perform a multi-turn tomography with a high and stable vacuum pressure. The tank allows to plug different measurement equipment additionally to the CCD Camera installed, to perform optical beam tomography. A collection of developed algorithms provides information about the density distribution, shape, size, location and emittance on the basis of CCD images. Simulated, as well as measured data have been applied to the evaluation algorithms to test the reliability of the beam. The actual contribution gives an overview on the current diagnostic possibilities of this diagnostic system.
	Poster TUPD60 [1.886 MB]

TUPD61	Multi Optical Transition Radiation System for ATF2	target, coupling, controls, extraction	446
	C. Blanch Gutierrez, J. Alabau-Gonzalvo, A. Faus-Golfe, J.J. García-Garrigós IFIC, Valencia, Spain J. Cruz, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	Funding: FPA2010-21456-C02-00 In this paper we describe the calibration tests, software development and first measurements of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. First 2D emittance measurements have been made with success and the system is being used normally for coupling correction. 4D emittance reconstruction algorithm is under improvement and implementation before a systematic measurement campaign and comparison with wire scanners is done. This will be a definitive test of the OTR as a beam emittance diagnostic device, which will give the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter.

TUPD65	Four-Dimensional Transverse Emittance Measurement Unit for High Intensity Ion Beams	ion, rfq, background, vacuum	455
	S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.R. Lu, Z.X. Yuan, J. Zhao PKU/IHIP, Beijing, People's Republic of China H.T. Ren Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China An X-Y coplaner High Intensity Beam Emittance Measurement Unit named as HIBEMU-4 has been developed recently to measure the emmitance of 2 MeV/40mA D⁺ beam at the RFQ exit of PeKing University Neutron Imaging FaciliTY (PKUNIFTY). HIBEMU-4 is based on the slit-wire method, and has two groups of slits in the orthogonal directions. Equipped with user-oriented software, it is able to provide results as root-mean-square(rms) emittance, boundary emittance, Twiss-parameters and phase diagram. In this paper we will mainly discuss the strengths and limitations of HIBEMU-4 at the aspects of mechanical designing and data processing method. In addition the testing of HIBEMU-4 on 1MeV O+ beam as well as 2 MeV/40mA D⁺ is closely presented, which shows HIBEMU-4 is competent in high intensity beam (HIB) emmitance measurements.

TUPD85	Photoinjector Based MeV Electron Microscopy	electron, gun, laser, cathode	503
	J. Yang, K. Kan, T. Kondoh, Y. Yoshida ISIR, Osaka, Japan J. Urakawa KEK, Ibaraki, Japan
	A time-resolved MeV electron microscopy based on a photocathode rf electron gun is being developed in Osaka University to reveal the hidden dynamics of intricate molecular and atomic processes in materials. A new structure rf gun has been developed to generates a high-brightness femtosecond-bunch electron beam. The microscopy has been used successfully for the single-shot MeV electron diffraction measurement and the time-resolved measurement. The transverse emittance, bunch length and energy spread were diagnosed as the functions of the laser injection phase, the laser pulse width and the bunch charge. The growths of the emittance, bunch length and energy spread due to the rf and the space charge effects in the rf gun were investigated.

TUPD91	Comparative Studies of Reconstruction Methods to Achieve Multi-Dimensional Phase Space Information	diagnostics, proton, ion, FEL	521
	C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom D. Reggiani, M. Seidel PSI, Villigen, Switzerland
	High Intensity Proton Accelerators like SNS, PSI or future machines like ESS or Isis upgrade cannot tolerate high losses due to activation. Standard beam diagnostics may not provide enough information about potential loss sources like beam filamentation or halo. Moreover, the application of interceptive methods like slits or pepperpot can be seriously discouraged by either high power deposition or explicit requirements for non-destructive methods like on-line diagnostics near superconducting cavities. Reconstruction of the beam distribution with a tomography method based on Maximum Entropy could help to overcome those problems and is easily to integrate in already existing facilities because the algorithm does not depend on the experimental profile measurement technique. Furthermore beam tomography can be employed on both spatial and phase-space reconstruction. The paper compares results from two different software packages from PSI (Maximum Entropy Tomography MENT) with the code used at RAL (MemSys 5).

TUPD97	Diagnostic System of TAC IR FEL Facility	electron, FEL, linac, diagnostics	536
	Z. Nergiz N.U, Nigde, Turkey A. Aksoy Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey S. Ceylan, S. Özkorucuklu SDU, Isparta, Turkey C. Kaya HZDR, Dresden, Germany
	The TAC (Turkish Accelerator Center) IR FEL facility which is named as Turkish Accelerator and Radiation Laboratory at Ankara, TARLA will be based on a 15-40 MeV electron linac accompanying two different undulators with 2.5 cm and 9 cm periods in order to obtain IR FEL ranging between 2-250 microns. The electron linac will consist of two sequenced modules, each housing two 9-cell superconducting TESLA cavities for cw operation. It is planned that the TARLA facility will be completed in 2013 at Golbasi campus of Ankara University. This facility will give an opportunity to the scientists and industry to use FEL in research and development in Turkey and our region. In this study, the main structure of the facility and planned electron beam diagnostics system is given in detail.
	Poster TUPD97 [0.514 MB]

WEOA01	Summary of COTR Effects	radiation, FEL, diagnostics, electron	539
	S. Wesch, B. Schmidt DESY, Hamburg, Germany
	Coherent transition radiation in the visible regime (COTR) has become a serious issue in FEL - Linacs disturbing the measurement of beam profiles by OTR screens up to a level, where this diagnostics becomes totally impossible. The talk will summarize the measured COTR effects from LCLS, FLASH and other machines and the investigations done so far into the dependence of the effect on beam and machine parameters. The status of the theoretical background and understanding of its origin will be discussed as well as proposals and experiences with possible remedies.
	Slides WEOA01 [2.520 MB]

WEOA04	Synchrotron Radiation Measurements at the CERN LHC	ion, proton, photon, booster	550
	F. Roncarolo, S. Bart Pedersen, A. Boccardi, E. Bravin, A. Guerrero, A. Jeff, T. Lefèvre, A. Rabiller CERN, Geneva, Switzerland A.S. Fisher SLAC, Menlo Park, California, USA
	The CERN LHC is equipped with two systems (one for each beam) designed to image the synchrotron radiation emitted by protons and heavy ions. After their commissioning in 2009, the detectors were extensively used and studied during the 2010 run. This allowed preliminary limits in terms of sensitivity, accuracy and resolution to be established. The upgrade to an intensified video camera capable of gating down to 25ns permitted the acquisition of single bunch profiles even with an LHC proton pilot bunch (~5·10⁹ protons) at 450 GeV or a single lead ion bunch (~10⁸ ions) from about 2 TeV. Plans for the optimization and upgrade of the system will be discussed. Since few months, part of the extracted light is deviated to the novel Longitudinal Density Monitor (LDM), consisting in an avalanche photo-diode detector providing a resolution better than 100 ps. The LDM system description will be complemented with the promising first measurement results.
	Slides WEOA04 [6.398 MB]

WEOB03	Single-shot Resolution of X-ray Monitor using Coded Aperture Imaging	photon, synchrotron, synchrotron-radiation, optics	561
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi KEK, Ibaraki, Japan J.P. Alexander, M.A. Palmer, D.P. Peterson, N.T. Rider CLASSE, Ithaca, New York, USA G.S. Varner UH, Honolulu, HI, USA
	We report on tests of an x-ray beam size monitor based on coded aperture imaging. This technique uses a mask pattern to modulate incoming light, with the resulting image being deconvolved through the mask and detector responses, including the effects of diffraction and attenuation materials in the path, over the spectral and angular distribution of the synchrotron radiation generated by the beam. We have tested mask patterns called URA masks, which have relatively flat spatial frequency response, and an open aperture of 50% for high-flux throughput, enabling single-shot (bunch-by-bunch, turn-by-turn) measurements without the need for heat-sensitive mirrors. Bunch size measurements of ~10 micron bunches with single-shot (statistics-dominated) resolutions of ~2.5 microns have been demonstrated at CesrTA, and single-shot measurements with similar or better resolution of beams in the ~5 micron range are being aimed for at the ATF2. A beam-size monitor based on these principles is also being designed for the SuperKEKB low-emittance rings. We will present estimated single-shot resolutions, along with a comparison to single-shot resolution measurements made at CesrTA.
	Slides WEOB03 [1.694 MB]

Paper

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MOOB02

Emittance and Energy Spread Measurements of Relativistic Electrons From Laser-Driven Accelerator

electron, laser, plasma, brightness

9

G.G. Manahan, M.P. Anania, C. Aniculaesei, E. Brunetti, S. Cipiccia, B. Ersfeld, M.R. Islam, R.C. Issac, D.A. Jaroszynski, R.P. Shanks, G.H. Welsh, S.M. Wiggins
USTRAT/SUPA, Glasgow, United Kingdom

Funding: Funding supported by U.K. EPSRC and the Scottish Universities Physics Alliance.
In this paper, we present a single-shot transverse emittance measurement for 125 ± 3 MeV electron beam using pepper-pot technique. A normalised transverse emittance as low as 1.1 ± 0.1 π-mm-mrad was measured using this method. Considering 60 consecutive shots, an average normalised emittance of ε_rms,x,y=2.2 ± 0.7, 2.3 ± 0.6 π-mm-mrad was obtained, which is comparable to a conventional linear accelerator. We also obtained high energy monoenergetic electron beam with relative energy spread less than 1%. The measured transverse emittance characterises the quality of an electron beam generated from laser-driven accelerator. Brightness, parallelism and focusability are all functions of the emittance. The low emittance and energy spread indicates that this type of accelerator is suitable for compact free electron laser driver.

Slides MOOB02 [7.052 MB]

MOPD06

Capabilities and Performance of the LHC Schottky Monitors

pick-up, injection, impedance, proton

44

M. Favier, T.B. Bogey, F. Caspers, O.R. Jones
CERN, Geneva, Switzerland
J. Cai, E.S.M. McCrory, R.J. Pasquinelli
Fermilab, Batavia, USA
A. Jansson
ESS, Lund, Sweden

The LHC Schottky system has been under commissioning since summer 2010. This non destructive observation relies on a slotted waveguide structure resonating at 4.8GHz. Four monitors, one for each plane of the two counter-rotating LHC beams, are used to measure the transverse Schottky sidebands Electronic gating allows selective bunch-by-bunch measurements, while a triple down-mixing scheme combined with heavy filtering gives an instantaneous dynamic range of over 100dB within a 20kHz bandwidth. Observations of both proton and lead ion Schottky spectra will be discussed along with a comparison of predicted and measured performance.

Poster MOPD06 [3.484 MB]

MOPD12

Expressing Properties of BPM Measurement System in Terms of Error Emittance and Error Twiss Parameters

betatron, FEL, beam-transport, focusing

62

V. Balandin, W. Decking, N. Golubeva
DESY, Hamburg, Germany

The determination of variations in the beam position and in the beam energy using BPM readings is one of the standard problems of accelerator physics. If the optical model of the beam line and BPM resolutions are known, the typical choice is to let jitter parameters be a solution of the weighted linear least squares problem. For transversely uncoupled motion this least squares problem can be solved analytically, but the direct usage of the obtained solution as a tool for designing a BPM measurement system is not straightforward. A better understanding of the nature of the problem is needed. In this paper we show that properties of the BPM measurement system can be described in terms of the usual accelerator physics concepts of emittance, energy spread, dispersions and betatron functions. In this way one can compare two BPM systems comparing their so-called error emittances and error energy spreads, or, for a given measurement system, one can achieve a balance between coordinate and momentum reconstruction errors by matching the error betatron functions in the point of interest to the desired values.

MOPD45

Single-Shot Beam Characterization Device Based on the Pepper-Pot Principle

ion, electron, permanent-magnet, beam-transport

155

S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Z.X. Yuan, J. Zhao
PKU/IHIP, Beijing, People's Republic of China
H.T. Ren
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Funding: National Nutural Science Foundation of China No.11075008
For the characterization of an ampere-scale microsecond single-pulse ion beam, a pepper-pot based beam profile measurement device was developed in PekingUniversity(PKU). It is a combination of Faraday cup technique with pepper-pot measurement facility. The direct Faraday cup is used to observe the total beam current and an array of pepper-pot diamond holes at the bottom of the Faraday cup is served to separate a large beam into several beamlets for beam distribution measurement. A Faraday array that locates 3.8 mm away from the pepper-pot screen is used to measure the transverse size of the beam. Two sets of permanent magnet poles that locate at the entrance of the Faraday cup and just before the Faraday array respectively are used to suppressing the second electrons produced by the interaction of the beam with target. In this paper we emphasize details of the experimental setup, the results of the measurements and we give an outlook on further developments on pepper-pot devices.

MOPD49

Beam Parameters Measurements by Ionization Cross Section Monitor on Proton LINAC of INR RAS

linac, radiation, ion, proton

161

P.I. Reinhardt-Nickoulin, S. Bragin, A. Feschenko, S.A. Gavrilov, I.V. Vasilyev, O. Volodkevich
RAS/INR, Moscow, Russia

The ionization beam cross section monitor (BCSM) is developed and used on proton linac of INR RAS to provide non-intercepting measurements of beam parameters. Operation of the monitor is based on utilization of residual gas ionization. The BCSM configuration design and image processing system are described and estimations of influence of the linac radiation background are discussed. The monitor enables to observe beam cross section and extract from it beam profiles and position as well as their evolution in time within a wide range of beam intensities and energies. The available experimental results of beam spot, profiles and emittances measurements at the linac output are presented.

MOPD52

First Results from Beam Measurements at the 3 MeV Test Stand for CERN Linac4

solenoid, linac, rfq, proton

167

B. Cheymol, J.-B. Lallement, A.E. Lokhovitskiy, O. Midttun, U. Raich, F. Roncarolo, R. Scrivens, E. Zorin
CERN, Geneva, Switzerland
B. Cheymol
Université Blaise Pascal, Clermont-Ferrand, France

The H⁻ source and the low energy beam line will determine to a large extend the performance of Linac-4, the new machine foreseen as injector into the PS Booster. For this reason a test stand will be set up consisting of the source, Low Energy Beam Transport (LEBT), RFQ and chopper line. Up to now only the source and LEBT are installed. First measurements have been performed using a Faraday Cup to measure the total source intensity, a slit-&-grid emittance meter for transverse emittance measurements and a spectrometer for energy spread measurements. This paper discusses the results from measurements on H⁻ beams at 35kV extraction voltage as well as protons at 45 kV, showing the emittance dependence on source RF power as well as the influence of a solenoid in splitting the beam into its various constituents: protons, H0, H²⁺ and H³⁺. Energy spread measurements are also presented.

MOPD57

Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations

ion, linac, target, alignment

179

E. Gütlich, P. Forck, B. Walasek-Höhne
GSI, Darmstadt, Germany
W. Ensinger
TU Darmstadt, Darmstadt, Germany

Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al₂O₃ with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al₂O₃ this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators.

MOPD61

Vertical Emittance Measurement at the ESRF

radiation, photon, synchrotron, dipole

188

F. Ewald, P. Elleaume, L. Farvacque, A. Franchi, D. Robinson, K.B. Scheidt, A. Snigirev, I. Snigireva
ESRF, Grenoble, France

In the short term the ESRF aims to reach emittances of less than 2 pm. We review the existing emittance diagnostics – X-ray projection monitors and pinhole cameras – and evaluate their ability to resolve such ultra-small vertical emittances. Even though these devices are reliable and show good agreement between measurements and theoretical predictions down to vertical emittance values of less than 10 pm, they will reach their limit of resolution for emittances decreasing below a few picometers. In addition to the existing emittance diagnostics, a new device was installed that images bending magnet radiation using compound refractive lenses (CRLs).

MOPD62

Storage Ring Injector Diagnostics using Synchrotron Radiation

injection, diagnostics, radiation, booster

191

A.F.D. Morgan, C.A. Thomas
Diamond, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

The state of the Diamond injector can be passively monitored using beam profile measurements of synchrotron radiation from bending magnets. This provides us with information on the characteristics of the beam injected into the storage ring. Using a numerical fit we are able to retrieve key parameters like beam position, size and tilt angle from every shot. This enables us to gather longer term trends to monitor for any changes during top-up operation in order to better understand any variability of the injector. We present here the study and the analysis performed with this diagnostic with the results from several months of operation.

Poster MOPD62 [0.451 MB]

MOPD69

Tune Measurements with High Intensity Beams at SIS-18

injection, acceleration, monitoring, diagnostics

206

R. Singh, P. Forck, W. Kaufmann, P. Kowina
GSI, Darmstadt, Germany
R. Singh
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork), Project Number ITN-2008-215080
To achieve high current operation close to the space charge limit in a synchrotron, a precise tune measurement during a full accelerating cycle is required. A tune measurement system that was recently commissioned at GSI synchrotron SIS-18 allows for online evaluation of the actual tune. This system consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations of the beam. The BPM signals thus induced are digitized by fast ADCs at 125 MSa/s and then the post processing electronics integrates the data bunch by bunch to obtain one position value per bunch. Subsequently base band tune is determined by Fourier transformation of the position data. The tune variation during acceleration for various beam conditions was measured using this system and is discussed. A detailed investigation of the incoherent tune shift was conducted with Uranium ion beams at the injection energy of 11.6 MeV/u. The results show the influence of beam current on the tune spectrum. In addition, the effects of the measurement method on the beam emittance and beam losses are discussed.

MOPD84

Hollow Photocathode Prototype for e-Gun

laser, cathode, electron, niobium

242

M.A. Nozdrin, N. Balalykin, A.A. Feshchenko, V. Minashkin, G. Shirkov, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
S. Gazi, J. Huran
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic

Photocathodes are important devices for contemporary electron accelerators. Significant photocathode parameters are: fast response time, quantum efficiency, long lifetime, low emittance and minimal effect on RF properties of the accelerating system. In this paper development of the hollow photocathode conception is presented and prototype is described. Such cathode geometry allows quantum efficiency rising due to surface photoelectric effect which is concerned with normal to material surface wave electric field multiplier. Experimental results of hollow photocathode using efficiency are given (266nm wavelength, 15 ns pulse time with 1 Hz repetition rate). Backside irradiation radically simplifies laser beam targeting on emitting surface, accelerator equipment adjustment and allows photocathode working surface laser cleaning.

Poster MOPD84 [1.505 MB]

MOPD85

Beam Emittance Studies at the Heavy Ion Linac UNILAC

rfq, ion, linac, DTL

245

P. Gerhard, W.A. Barth, L.A. Dahl, L. Groening, H. Vormann
GSI, Darmstadt, Germany

New accelerating structures for the UNILAC at GSI were commissioned in the last two years [1, 2], and major machine upgrades in order to meet the requirements for FAIR are in preparation [3, 4]. Beam emittance is one of the key beam parameters that are essential for any beam dynamics calculation, for the design of new accelerators as well as verification or investigation of existing machines. Its measurement is intricate and often time consuming. Extensive emittance measurements went along with the commissionings and were conducted to provide a reliable basis for beam dynamics simulations. In addition to the 10 permanent transverse emittance measurement devices installed all over the UNILAC, two "mobile" devices had been built and mounted at four different sites in the UNILAC. This work shows the standard slid-grid device used for transverse beam emittance measurements and gives an overview of the activities and results. The following topics will be presented with respect to design studies and simulations: Emittance growth of high current ion beams along the UNILAC, stripping, and resonance effects.
[1] H. Vormann et al., LINAC10, MOP040
[2] P. Gerhard et al., IPAC10, MOPD028
[3] W. Barth et al., PAC09, FR5REP059
[4] S. Mickat et al., LINAC10, MOP042

Poster MOPD85 [10.077 MB]

MOPD88

Electron Beam Ion Sources, Ion Optical Elements and Beam Diagnostics for Particle Accelerators

ion, electron, ion-source, injection

254

F. Ullmann, V.P. Ovsyannikov, M. Schmidt
DREEBIT GmbH, Dresden, Germany
G. Zschornack
Technische Universität Dresden, Institut für Angewandte Physik, Dresden, Germany

Electron Beam Ion Sources (EBISs) provide highly charged ions (HCIs) for a variety of investigations and applications, amongst others as injection source for particle accelerators. EBISs feature a lot of advantages which qualify them for accelerator injection, and which partly compensate their comparatively low number of particles. DREEBIT GmbH provides a family of compact EBISs based on permanent magnets. A more sophisticated version is based on cryogen-free superconducting magnets providing a higher ion output. Its compact design makes them transportable, low in operational costs, and guarantee easy handling. We present latest improvements and measurements proving the feasibility of producing beams of HCIs with convenient beam properties such as low transversal and longitudinal emittance. In addition we present a variety of ion optical elements and ion beam diagnostics. The DREEBIT Wien filter allows for the charge mass separation. The DREEBIT Pepper-pot Emittance Meter allows for emittance measurements of beams of a wide range of particle intensity. Other beam diagnostics are provided, such as Beam Imaging System, Retarding Field Analyzer and different kinds of Faraday cups.

TUPD04

Diagnostics for the 150 MeV Linac and Test Transport Line of Taiwan Photon Source

linac, diagnostics, site, electron

308

C.-Y. Liao, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, S.Y. Hsu, K.H. Hu, C.H. Kuo, D. Lee, K.-K. Lin, K.L. Tsai, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The TPS 150 MeV linac is in installation and commissioning phase at the test site for acceptance test. The linac will move to the final installation site after the building complete which is expected in 2012. The linac and a short transport line for main parameters measurement equips with several types of diagnostic devices, which include screen monitors, fast current transformers, integrated current transformer, wall current monitors, beam position monitors and Faraday cups. These devices are arranged to measure the specification parameters such as charge in bunch train, pulse purity, energy, energy spread, and emittance. Implementation details and preliminary test results will be summarized in this report.

TUPD07

Instrumentation Needs and Solutions for the Development of an SRF Photoelectron Injector at the Energy-Recovery Linac BERLinPro

gun, SRF, laser, cavity

317

R. Barday, T. Kamps, A. Neumann, J. Rudolph, S.G. Schubert, J. Völker
HZB, Berlin, Germany
A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany

BERLinPro is an energy-recovery linac for an electron beam with 1 mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. Development of this source is a major part of the BERLinPro programme. The instrumentation for the first stage of the programme serves the purpose to have robust and reliable monitors for fundamental beam parameters like emittance, bunch charge, energy and energy spread. The critical issue of the second stage is the generation of an electron beam with 100 mA average current and a normalized emittance of 1 mm mrad. Therefore we plan to setup a dedicated instrumentation beamline with a compact DC gun to measure thermal emittance, current and current lifetime. In parallel an SRF gun with dedicated diagnostics will be build focused on ERL specific aspects like emittance compensation with low-energy beams and reliability of high current operation. This paper collects requirements for each development stage and discusses solutions to specific measurement problems.

TUPD31

Measurement of the Slice Energy Spread Induced by a Transverse Deflecting RF Structure at FLASH

electron, RF-structure, FEL, free-electron-laser

371

C. Gerth, C. Behrens
DESY, Hamburg, Germany

Operation of a high-gain free-electron laser requires a high-brightness electron beam with high peak current and small slice energy spread. The slice energy spread can be measured with high longitudinal resolution by using a transverse deflecting structure in combination with viewing screen in a dispersive section. However, off-axis accelerating fields induce a correlated energy spread that depends inversely proportional on the longitudinal resolution. As a consequence, short bunches, which intrinsically require a high longitudinal resolution in order to be diagnosed, suffer from a large induced energy spread which limits the energy resolution. To be able to measure the impact of the transverse deflecting structure on the slice energy spread without distortions by space charge or coherent synchrotron radiation effects, we tailored short electron bunches with low peak currents by clipping low energy electrons in the collimator of the first bunch compressor at FLASH. In this paper, we present first systematic measurements of the correlated energy spread induced by a transverse deflecting structure. The results are compared with analytical calculations.

TUPD50

Slice-Emittance Measurements at ELBE / SRF-Injector

electron, simulation, SRF, quadrupole

416

J. Rudolph, M. Abo-Bakr, T. Kamps
HZB, Berlin, Germany
J. Teichert
HZDR, Dresden, Germany

Funding: Supported by the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, contract number 227579)
The linear accelerator ELBE delivers high-brightness electron bunches to multiple user stations, including an IR-FEL. The current thermionic injector is being replaced by a superconducting rf photoinjector (SRF-injector) which promises higher beam quality. Using a transfer chicane, beam from the SRF-injector can be injected into the ELBE linac. Detailed characterization of the electron beam is achieved by measuring the vertical slice emittance of the beam. To perform this measurement a combination of rf zero-phasing, spectrometer dipole and quadrupole scan is used. The electron beam is accelerated by the first cavity of the ELBE accelerator module and send through a second cavity which is operated at zero-crossing of the rf. In doing so a linear energy-time correlation is induced to the beam. The chirped beam is send through a spectrometer dipole and the longitudinal distribution can be made visible on a scintillator screen. Performing a quadrupole scan allows the determination of the emittance for different slices. This paper explains the working principle of the method and the experimental setup and shows results of performed simulations as well as first measurement results.

TUPD56

High Resolution SR Profile Monitor at ATF2 Extraction Line

extraction, background, controls, damping

434

T. Naito, T.M. Mitsuhashi
KEK, Ibaraki, Japan

The profile monitor using visible light of the SR at ATF2 extraction line has been developed. KEK-ATF is a facility to produce extremely low emittance beam for the linear collider. The emittance in the damping ring is ex=1x10^-9 m and ey=1x10{-11} m, respectively. The ATF2 extraction line is a transport line to study the Final focus system for the linear collider. The designed beam size at the profile monitor is 230 μm in horizontal and 13 μm in vertical. We used a wide aperture optical system to reduce the Rayleigh limit of the optical system. The performance of the monitor is reported.

TUPD60

Optical Diagnostics for Frankfurt Neutron Source

diagnostics, simulation, factory, neutron

443

H. Reichau, O. Meusel, U. Ratzinger, C. Wagner
IAP, Frankfurt am Main, Germany

A non-interceptive optical diagnostic system on the basis of beam tomography, was developed for the planned Frankfurt Neutron Source (FRANZ). The proton driver linac of FRANZ will provide energies up to 2.0 MeV. The measurement device will non-interceptively derive required beam parameters at the end of the LEBT at beam energies of 120 keV and a current of 200 mA. On a narrow space of 351.2 mm length a rotatable tomography tank will perform a multi-turn tomography with a high and stable vacuum pressure. The tank allows to plug different measurement equipment additionally to the CCD Camera installed, to perform optical beam tomography. A collection of developed algorithms provides information about the density distribution, shape, size, location and emittance on the basis of CCD images. Simulated, as well as measured data have been applied to the evaluation algorithms to test the reliability of the beam. The actual contribution gives an overview on the current diagnostic possibilities of this diagnostic system.

Poster TUPD60 [1.886 MB]

TUPD61

Multi Optical Transition Radiation System for ATF2

target, coupling, controls, extraction

446

C. Blanch Gutierrez, J. Alabau-Gonzalvo, A. Faus-Golfe, J.J. García-Garrigós
IFIC, Valencia, Spain
J. Cruz, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

Funding: FPA2010-21456-C02-00
In this paper we describe the calibration tests, software development and first measurements of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. First 2D emittance measurements have been made with success and the system is being used normally for coupling correction. 4D emittance reconstruction algorithm is under improvement and implementation before a systematic measurement campaign and comparison with wire scanners is done. This will be a definitive test of the OTR as a beam emittance diagnostic device, which will give the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter.

TUPD65

Four-Dimensional Transverse Emittance Measurement Unit for High Intensity Ion Beams

ion, rfq, background, vacuum

455

S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.R. Lu, Z.X. Yuan, J. Zhao
PKU/IHIP, Beijing, People's Republic of China
H.T. Ren
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China
An X-Y coplaner High Intensity Beam Emittance Measurement Unit named as HIBEMU-4 has been developed recently to measure the emmitance of 2 MeV/40mA D⁺ beam at the RFQ exit of PeKing University Neutron Imaging FaciliTY (PKUNIFTY). HIBEMU-4 is based on the slit-wire method, and has two groups of slits in the orthogonal directions. Equipped with user-oriented software, it is able to provide results as root-mean-square(rms) emittance, boundary emittance, Twiss-parameters and phase diagram. In this paper we will mainly discuss the strengths and limitations of HIBEMU-4 at the aspects of mechanical designing and data processing method. In addition the testing of HIBEMU-4 on 1MeV O+ beam as well as 2 MeV/40mA D⁺ is closely presented, which shows HIBEMU-4 is competent in high intensity beam (HIB) emmitance measurements.

TUPD85

Photoinjector Based MeV Electron Microscopy

electron, gun, laser, cathode

503

J. Yang, K. Kan, T. Kondoh, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

A time-resolved MeV electron microscopy based on a photocathode rf electron gun is being developed in Osaka University to reveal the hidden dynamics of intricate molecular and atomic processes in materials. A new structure rf gun has been developed to generates a high-brightness femtosecond-bunch electron beam. The microscopy has been used successfully for the single-shot MeV electron diffraction measurement and the time-resolved measurement. The transverse emittance, bunch length and energy spread were diagnosed as the functions of the laser injection phase, the laser pulse width and the bunch charge. The growths of the emittance, bunch length and energy spread due to the rf and the space charge effects in the rf gun were investigated.

TUPD91

Comparative Studies of Reconstruction Methods to Achieve Multi-Dimensional Phase Space Information

diagnostics, proton, ion, FEL

521

C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
D. Reggiani, M. Seidel
PSI, Villigen, Switzerland

High Intensity Proton Accelerators like SNS, PSI or future machines like ESS or Isis upgrade cannot tolerate high losses due to activation. Standard beam diagnostics may not provide enough information about potential loss sources like beam filamentation or halo. Moreover, the application of interceptive methods like slits or pepperpot can be seriously discouraged by either high power deposition or explicit requirements for non-destructive methods like on-line diagnostics near superconducting cavities. Reconstruction of the beam distribution with a tomography method based on Maximum Entropy could help to overcome those problems and is easily to integrate in already existing facilities because the algorithm does not depend on the experimental profile measurement technique. Furthermore beam tomography can be employed on both spatial and phase-space reconstruction. The paper compares results from two different software packages from PSI (Maximum Entropy Tomography MENT) with the code used at RAL (MemSys 5).

TUPD97

Diagnostic System of TAC IR FEL Facility

electron, FEL, linac, diagnostics

536

Z. Nergiz
N.U, Nigde, Turkey
A. Aksoy
Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey
S. Ceylan, S. Özkorucuklu
SDU, Isparta, Turkey
C. Kaya
HZDR, Dresden, Germany

The TAC (Turkish Accelerator Center) IR FEL facility which is named as Turkish Accelerator and Radiation Laboratory at Ankara, TARLA will be based on a 15-40 MeV electron linac accompanying two different undulators with 2.5 cm and 9 cm periods in order to obtain IR FEL ranging between 2-250 microns. The electron linac will consist of two sequenced modules, each housing two 9-cell superconducting TESLA cavities for cw operation. It is planned that the TARLA facility will be completed in 2013 at Golbasi campus of Ankara University. This facility will give an opportunity to the scientists and industry to use FEL in research and development in Turkey and our region. In this study, the main structure of the facility and planned electron beam diagnostics system is given in detail.

Poster TUPD97 [0.514 MB]

WEOA01

Summary of COTR Effects

radiation, FEL, diagnostics, electron

539

S. Wesch, B. Schmidt
DESY, Hamburg, Germany

Coherent transition radiation in the visible regime (COTR) has become a serious issue in FEL - Linacs disturbing the measurement of beam profiles by OTR screens up to a level, where this diagnostics becomes totally impossible. The talk will summarize the measured COTR effects from LCLS, FLASH and other machines and the investigations done so far into the dependence of the effect on beam and machine parameters. The status of the theoretical background and understanding of its origin will be discussed as well as proposals and experiences with possible remedies.

Slides WEOA01 [2.520 MB]

WEOA04

Synchrotron Radiation Measurements at the CERN LHC

ion, proton, photon, booster

550

F. Roncarolo, S. Bart Pedersen, A. Boccardi, E. Bravin, A. Guerrero, A. Jeff, T. Lefèvre, A. Rabiller
CERN, Geneva, Switzerland
A.S. Fisher
SLAC, Menlo Park, California, USA

The CERN LHC is equipped with two systems (one for each beam) designed to image the synchrotron radiation emitted by protons and heavy ions. After their commissioning in 2009, the detectors were extensively used and studied during the 2010 run. This allowed preliminary limits in terms of sensitivity, accuracy and resolution to be established. The upgrade to an intensified video camera capable of gating down to 25ns permitted the acquisition of single bunch profiles even with an LHC proton pilot bunch (~5·10⁹ protons) at 450 GeV or a single lead ion bunch (~10⁸ ions) from about 2 TeV. Plans for the optimization and upgrade of the system will be discussed. Since few months, part of the extracted light is deviated to the novel Longitudinal Density Monitor (LDM), consisting in an avalanche photo-diode detector providing a resolution better than 100 ps. The LDM system description will be complemented with the promising first measurement results.

Slides WEOA04 [6.398 MB]

WEOB03

Single-shot Resolution of X-ray Monitor using Coded Aperture Imaging

photon, synchrotron, synchrotron-radiation, optics

561

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi
KEK, Ibaraki, Japan
J.P. Alexander, M.A. Palmer, D.P. Peterson, N.T. Rider
CLASSE, Ithaca, New York, USA
G.S. Varner
UH, Honolulu, HI, USA

We report on tests of an x-ray beam size monitor based on coded aperture imaging. This technique uses a mask pattern to modulate incoming light, with the resulting image being deconvolved through the mask and detector responses, including the effects of diffraction and attenuation materials in the path, over the spectral and angular distribution of the synchrotron radiation generated by the beam. We have tested mask patterns called URA masks, which have relatively flat spatial frequency response, and an open aperture of 50% for high-flux throughput, enabling single-shot (bunch-by-bunch, turn-by-turn) measurements without the need for heat-sensitive mirrors. Bunch size measurements of ~10 micron bunches with single-shot (statistics-dominated) resolutions of ~2.5 microns have been demonstrated at CesrTA, and single-shot measurements with similar or better resolution of beams in the ~5 micron range are being aimed for at the ATF2. A beam-size monitor based on these principles is also being designed for the SuperKEKB low-emittance rings. We will present estimated single-shot resolutions, along with a comparison to single-shot resolution measurements made at CesrTA.

Slides WEOB03 [1.694 MB]