DIPAC2011 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MOOB02	Emittance and Energy Spread Measurements of Relativistic Electrons From Laser-Driven Accelerator	emittance, 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]

MOOB03	Diamond-based Beam Halo Monitor Equipped with RF Fingers for SACLA	wakefield, simulation, vacuum, radiation	12
	H. Aoyagi, T. Aoki, T. Bizen, K. Fukami, N. Nariyama, S. Suzuki JASRI/SPring-8, Hyogo-ken, Japan Y. Asano, T. Itoga, H. Kitamura, T. Tanaka RIKEN/SPring-8, Hyogo, Japan
	Funding: This work is partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (c) 21604017. The diamond-based beam halo monitor has been developed for SPring-8 Angstrom Compact free electron LAser (SACLA). This monitor is an interlock sensor to protect the undulator magnets against radiation damage. Pulse-mode measurement is adopted to suppress the background noise efficiently. The diamond detectors are dipped into the beam duct in order that the intensity of the beam halo can be measured directly. However, it is important issue to avoid degradation in quality of electron beam for SPring-8 XFEL. We designed new RF fingers with aluminum windows in order to reduce the impedance to the beam. The RF fingers are made of beryllium copper, and having the aluminum windows, which is low-Z material, in front of active areas of the diamond detectors. Therefore, the influence of secondary electrons and bremsstrahlung from the finger material can be suppressed. To evaluate influence on the output signal of the diamond detector by changing the finger material, both the simulation study and the experimental measurement have been carried out. Feasibility tests of this monitor, which is equipped with the RF fingers, have also been demonstrated at the SCSS test accelerator.
	Slides MOOB03 [1.353 MB]

MOPD04	RHIC Electron Lens Test Bench Diagnostics	ion, diagnostics, gun, solenoid	38
	D.M. Gassner, E.N. Beebe, W. Fischer, X. Gu, K. Hamdi, J. Hock, C. Liu, T.A. Miller, A.I. Pikin, P. Thieberger BNL, Upton, Long Island, New York, USA
	An Electron Lens system will be installed in RHIC to increase luminosity by counteracting the head-on beam-beam interaction. The proton beam collisions at the two experimental locations will introduce a tune spread due to a difference of tune shifts between small and large amplitude particles. A low energy electron beam will be used to improve luminosity and lifetime of the colliding beams by reducing the betatron tune shift and spread. In preparation for the Electron Lens installation next year, a test bench facility will be used to gain experience with all sub-systems. This paper will discuss the diagnostics related to measuring the electron beam parameters.

MOPD09	Electron Beam Diagnostics for FLASH II	diagnostics, undulator, radiation, laser	53
	N. Baboi, D. Nölle DESY, Hamburg, Germany
	Up to now, the FLASH linac serves one SASE (Self-Amplified Spontaneous Emission) undulator. The radiation produced can be guided to one of 5 beamlines in the experimental hall. In order to increase the availability of the machine, an extension, FLASH II, will be built in the next few years. A second undulator section will be built to generate SASE light. A HHG (High Harmonic Generation) laser will alternatively be used to produce seeded radiation in the undulators. The electron beam diagnostics in FLASH II has to enable the precise control of the beam position, size, timing, as well as the overlap of the electron beam with the HHG laser. The losses have to be kept under control, and the beam has to terminate safely in the beam dump. In comparison to FLASH, which was designed to run with rather high charge, the dynamic range of the diagnostics has to be between 0.1 to 1 nC, similar to the European XFEL. This paper gives an overview of the diagnostics for FLASH II.

MOPD14	Calibration of the Electrostatic Beam Position Monitors for VEPP-2000	vacuum, pick-up, optics, positron	68
	Yu. A. Rogovsky, I. Nesterenko BINP SB RAS, Novosibirsk, Russia
	The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.
	Poster MOPD14 [0.393 MB]

MOPD17	Beam-based HOM Study in Third Harmonic SC Cavities for Beam Alignment at FLASH	HOM, cavity, dipole, polarization	77
	P. Zhang, R.M. Jones, I.R.R. Shinton UMAN, Manchester, United Kingdom N. Baboi, B. Lorbeer, P. Zhang DESY, Hamburg, Germany H. Ecklebe, T. Flisgen, H.-W. Glock Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by European Commission under the FP7 Research Infrastructures grant agreement No.227579. An electron beam entering an accelerator cavity excites higher order modes (HOM). These are radiated to HOM couplers, subsequently damped, and can also be used to facilitate beam monitoring. The modes which deflect the beam transversely are the focus of this study and are used to monitor the beam position. Results are presented on the first analysis of beam alignment based on HOM signals from the third harmonic cavities at FLASH. The electrical center of each mode is ascertained by moving the beam to minimize the HOM signal detected. A single electron bunch per RF pulse is used.

MOPD20	Applicability of the AM-PM Conversion Method to Beam Position Monitoring of Electron Beams accelerated in S-Band Frequency Range	pick-up, insertion, controls, monitoring	86
	M. Ruf, P. Quednau, L. Schmidt U. Erlangen-Nurnberg LHFT, Erlangen, Germany S. Setzer Siemens Med, Erlangen, Germany
	Funding: Work supported by Bayerische Forschungsstiftung in the project "MEDieMAS - Effiziente Bestrahlungsgeräte für Krebstherapie (Efficient radiation systems for cancer therapy)", file number AZ-735-07 In this paper, the applicability of the amplitude-to-phase-conversion (AM-PM) method to beam position monitoring (BPM) purposes in S-Band frequency range is investigated. The proof-of-principle experiment is done by AM-PM-processing of capacitive pickup signals generated by a 6 MeV S-Band electron beam. It is demonstrated that the AM-PM-output pulsed DC signal is proportional to transverse beam offsets. Furthermore, design considerations and selection criteria of appropriate RF devices are described. Additionally, results of cold measurements of a planar 2-channel AM-PM-receiver module are presented indicating that the applicability will also be given for even higher frequency ranges.

MOPD27	A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI	pick-up, ion, vacuum, impedance	107
	F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick GSI, Darmstadt, Germany Yu.A. Litvinov MPI-K, Heidelberg, Germany M.S. Sanjari IKF, Frankfurt am Main, Germany J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao IMP, Lanzhou, People's Republic of China
	A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD31	Future Timing and Synchronization Scheme at ELBE	laser, radiation, gun, controls	116
	M. Kuntzsch, A. Büchner, T. Kirschke, U. Lehnert, F. Röser HZDR, Dresden, Germany
	The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf is currently extended to offer capacity for new experiments. The reconstruction includes the setup of a THz-beamline with a dedicated user laboratory and a beamline for electron-beam - high-power laser experiments. The current synchronization scheme offers stability to the picoseconds level. The new experiments require a femtosecond synchronization in order to get field-strength resolved THz-probes and to have a stable overlap between the electron-bunches with the laser pulses. In the future there will be a MIT/DESY-like system [1] with a pulsed fiber laser as an optical reference oscillator. The laser pulses will be distributed over stabilized fiber links to the remote stations. Later on it is planned to install EOM-based beam arrival time monitors (BAMs) in order to monitor the bunch jitter and to establish a feedback system to reduce the jitter. Besides that, the timing system has to be revised to trigger experiments with low repetition rate, two guns (thermionic DC, superconducting RF) and lasers. The Poster will show the Layout of the possible future Timing and Synchronization System at ELBE. [1] J. Kim, J.A. Cox, J.J. Chen, F.X. Kärtner, "Drift-free femtosecond timing synchronization of remote optical and microwave sources", Nature Photonics, Vol. 2, pp. 733-736 (2008).

MOPD33	Pickup Design for a High Resolution Bunch Arrival Time Monitor for FLASH and XFEL	pick-up, simulation, vacuum, laser	122
	A. Angelovski, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb DESY, Hamburg, Germany J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free Electron Laser in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAM’s) which are part of the optical synchronization system [1-2]. FLASH usually works with bunch charges of 0.2 to 1 nC, but for a variety of future experiments, the system needs to operate with bunch charges in the range of 10 to 20 pC. Below 0.2 nC the sensitivity of such a BAM scales approximately linearly with the bunch charge and therefore the system no longer fulfills the time resolution requirements for these low charges. For the low bunch charge regime operation, the bandwidth has to be increased substantially. This paper shows a new design of a high frequency button pickup that can operate in a frequency band from DC up to 40 GHz. The design criteria of the pickup are the voltage slope steepness at the zero-crossing, the maximum amplitude and the ringing of the picked-up voltage. The performance of the designed model is analyzed for fabrication tolerances and orbit variations. Some manufacturing and practical issues are discussed and solutions are offered for improving the results. A full wave simulation with CST PARTICLE STUDIO is performed in order to prove the concept. [1] F. Loehl et. al.,“A Sub 100 fs Electron Bunch Arrival-time Monitor System for FLASH”, THOBFI01, EPAC 2006 [2] F. Loehl et. al.,“A Sub-50 Femtosecond bunch arrival time monitor system for FLASH”, WEPB15, DIPAC 2007
	Poster MOPD33 [27.661 MB]

MOPD34	Analysis of New Pickup Designs for the FLASH and XFEL Bunch Arrival Time Monitor System	pick-up, simulation, laser, vacuum	125
	A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp TU Darmstadt, Darmstadt, Germany M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb DESY, Hamburg, Germany J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free Electron Laser in Hamburg (FLASH) is equipped with Bunch Arrival time Monitors (BAM)[1], which provide for a time resolution of less than 10 fs for bunch charges higher than 0.2 nC. Future experiments, however, will aim at generating FEL light pulses from bunch charges of 10-20 pC. The sensitivity of the measurement system is defined by the slope of the pickup signal at the zero crossing and scales close to linear with the bunch charge. The requirements on the time resolution will no longer be fulfilled when operating at decreased bunch charges. Several designs have been developed in CST PARTICLE STUDIO®, each having an increased bandwidth larger than 40 GHz for meeting the requirements when operating at low bunch charges. Furthermore, new post-processing functions for the automatic evaluation of the signal slope and the ringing in the detected voltage signal have been developed and implemented within the CST software for defining optimization goals of the built-in optimizer for determining free design parameters. Results of the new designs are presented and compared with the current BAM pickup. [1] M.K. Bock et.al., "Recent Developments of the Beam Arrival Time Monitor with Femtosecond Resolution at FLASH", WEOCMH02, IPAC 2010
	Poster MOPD34 [3.112 MB]

MOPD38	1-MHz Line Detector for Intra-bunch-train Multichannel Feedback	laser, radiation, feedback, diagnostics	137
	L. Kotynia, D.R. Makowski, A. Mielczarek, A. Napieralski TUL-DMCS, Łódź, Poland C. Gerth, T. Jezynski, H. Schlarb, B. Schmidt, B. Steffen DESY, Hamburg, Germany
	Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285). The measurement and control of the electron bunch length is one of the key diagnostics in linac-based free-electron lasers to reach the required peak current in the electron bunches. In order to use the multi-channel signals from longitudinal bunch shape measurements for intra train feedback for the European XFEL, line readout rates in the MHz range and low latencies are required, which is far more than commercial multichannel radiation detectors (line cameras) can provide. The paper presents a 256 channel detector that allows analyzing optical or infrared radiation with 1 MHz rate and a few microseconds latency using photodiode arrays, as needed for synchrotron light monitors, electro-optical bunch length measurements, or other laser based diagnostics. The proposed architecture aims at high frequency readout with low latency by using a multichannel electronic front-end designed for HEP, combined with Si or InGaAs detector arrays with very fast response time, and a low-latency data acquisition system. Currently the device is at the conceptual design stage.
	Poster MOPD38 [3.262 MB]

MOPD40	Beam Measurements with Visible Synchrotron Light at VEPP-2000 Collider	controls, collider, diagnostics, positron	140
	Yu. A. Rogovsky, D.E. Berkaev, I. Koop, A.N. Kyrpotin, I. Nesterenko, A.L. Romanov, Y.M. Shatunov, D.B. Shwartz BINP SB RAS, Novosibirsk, Russia
	This paper describes beam diagnostics at VEPP-2000 collider, based on visible synchrotron light analysis. These beam instruments include: SR beamline and optics; acquisition tools and high resolution CCD cameras distributed around the storage ring to measure the transverse beam profile and its position in vacuum chamber; photomultiplier tubes (PMT) which enables beam current measurements. Some applications of these measurement systems and their measurement results are presented.
	Poster MOPD40 [0.599 MB]

MOPD45	Single-Shot Beam Characterization Device Based on the Pepper-Pot Principle	ion, emittance, 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.

MOPD48	Optical Electron Beam Diagnostics for Relativistic Electron Cooling Devices	laser, scattering, photon, diagnostics	158
	T. Weilbach HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany J. Dietrich FZJ, Jülich, Germany
	New magnetized high energy coolers like the one proposed for the High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) have specific demands on the diagnostic of the electron beam. Due to high voltage breakdowns they only allow a very small beam loss so non-invasive beam diagnostic methods are necessary. For beam profile measurement a system based on beam induced fluorescence (BIF) was designed and is under installation at the 100 keV polarized test setup at the Mainzer Mikrotron (MAMI) at the moment. For the diagnostic of other observables of the cooling beam, like the electron beam energy or the electron temperature, a Thomson scattering experiment is planned at the same setup. The planned experiments for the beam profile measurement are presented and the challenges of the Thomson scattering method are discussed.

MOPD54	Commissioning Results of the Photon-Electron Diagnostic Unit at sFLASH	laser, undulator, diagnostics, FEL	173
	J. Bödewadt, E. Hass, J. Roßbach Uni HH, Hamburg, Germany
	Funding: Supported by the Federal Ministry of Education and Research of Germany under contract 05 ES7GU1 Recently a seeded free-electron laser operating in the extreme ultra-violet (XUV) spectral range was installed and commissioned at the free-electron laser FLASH. The seed beam is generated by higher harmonics of near infrared laser pulses. A dedicated transport system guides the radiation into the electron accelerator environment. Within the seed undulator section compact diagnostic units were installed to control the transverse overlap of the photon and the electron beam. These units contain a BPM, horizontal and vertical wire scanners and an OTR screen for the electron diagnostic. A Ce:YAG screen and a MCP readout for the wire scanner are used to measure the photon beam position. This paper presents the commissioning results and the performance of the diagnostic units.

MOPD77	Broadband Digital Feedback System for the VEPP-4M Electron-Positron Collider	feedback, kicker, betatron, positron	224
	V.V. Oreshonok, V.V. Smaluk BINP SB RAS, Novosibirsk, Russia V.P. Cherepanov, V.V. Oreshonok, D.P. Sukhanov NSU, Novosibirsk, Russia
	To suppress the transverse instability, which is the main reason of beam current limitation at the VEPP-4M electron-positron collider, a digital bunch-by-bunch feedback system has been developed, installed and commissioned. The real-time data processing is performed by a special code running in an FPGA module. This provides high efficiency and flexibility of the system. During the system commissioning, a 3-times increase of the beam current injected into VEPP-4M was reached. The system design and data processing algorithms are described, the commissioning results are presented.

MOPD78	Synchronous Measurement of Stability of Electron Beam, X-ray Beam, Ground and Cavity Voltage	cavity, feedback, photon, controls	227
	G. Rehm, M.G. Abbott, C. Bloomer, I. Uzun Diamond, Oxfordshire, United Kingdom
	We have developed hardware and software that allows continuous and synchronous recording of electron and X-Ray beam position as well as cavity voltage and ground vibrations at a rate of about 10kS/s for periods of many days. To this end, additional nodes have been added to our existing fast network that feeds the Fast Orbit Feedback System, namely tungsten vane type front end XBPMs, RF cavity pickups and accelerometers. The synchronous nature of these measurements shows the correlation between electron beam motion through an insertion device and observed X-ray beam motion in the frontend or orbit distortions caused by fluctuations of the RF cavity voltage. While the additional channels currently are only observed, the potential of including these in the fast orbit feedback will be discussed.

MOPD82	Installation for Measurements of Secondary Emission Yield and Electron Cloud Lifetime in Magnetic Field	cryogenics, cathode, vacuum, simulation	236
	A.A. Krasnov, V.V. Anashin, V.K. Ovchar, V.V. Smaluk, D.P. Sukhanov BINP SB RAS, Novosibirsk, Russia
	An experimental setup for investigations of electron-surface interaction and electron cloud behavior is under commissioning at BINP. The proposed method provides direct measurements of secondary emission yield and electron clouds lifetime in the presence of strong magnetic field. In principle, the experiments can be performed at cryogenic temperatures. The experimental data will help to figure out the process of reflection of low energy electrons from a metal surface and can be useful for improvement of computer codes developed for simulation of electron clouds behavior in a cold beam pipe of particle accelerators. The structure and performance capabilities of the setup are described, first experimental results are presented.

MOPD84	Hollow Photocathode Prototype for e-Gun	laser, cathode, niobium, emittance	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]

MOPD88	Electron Beam Ion Sources, Ion Optical Elements and Beam Diagnostics for Particle Accelerators	ion, emittance, 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.

MOPD91	Pulse-By-Pulse X-ray Beam Monitor Equipped with Microstripline Structure	high-voltage, diagnostics, impedance, pick-up	260
	H. Aoyagi, S. Takahashi JASRI/SPring-8, Hyogo-ken, Japan H. Kitamura RIKEN/SPring-8, Hyogo, Japan
	Pulse-by-pulse measurement of X-ray beam is import issue for the 3rd generation light sources in order not only to stabilize X-ray beam in an experimental hutch but also to diagnose electron beam in a storage ring. A new pulse-by-pulse X-ray beam monitor equipped with microstripline structure has been developed. The detector head has the microstripline structure. The impedance of the detector head is matched to 50 ohm. Thermodynamics of the detector head is also well considered against severe heat load. The advantage of this monitor is that output signal is short and unipolar pulse, so front-end electronics can be simplified. The feasibility tests have been demonstrated at the X-ray beamline of SPring-8 in the term of (1) pulse intensity monitor, (2) pulse-by-pulse X-ray beam position monitor, and (3) the pulse-timing monitor. Then, we have improved the structure of the detector head in order to sophisticate the function as the pulse timing monitor. As a result, we successfully removed the ringing parts of output signal, and demonstrated that this monitor can be used as the timing monitor. We also describe a new scheme for beam diagnostics using this monitor.
	Poster MOPD91 [1.309 MB]

MOPD93	Investigation of Diagnostic Techniques on a Nonneutral Plasma	plasma, space-charge, ion, diagnostics	266
	K. Schulte, M. Droba, O. Meusel, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: Work supported by HIC for FAIR, BMBF No. 06FY90891. Space charge lenses use a confined electron cloud for the focusing of ion beams. The focusing strength is given by the electron density whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The plasma parameters, loss as well as production mechanisms have a strong impact on plasma beam interactions. A scaled up space charge lens was constructed to investigate the properties of a nonneutral plasmas in detail. New non-interceptive diagnostic has been developed to characterize the collective behaviour of the confined nonneutral plasma in terms of an optimized lens design and parameters. Experimental results will be presented in comparison with numerical simulations.
	Poster MOPD93 [3.587 MB]

TUOA04	Instrumentation for Machine Protection at FERMI@Elettra	undulator, FEL, radiation, diagnostics	286
	L. Fröhlich, A.I. Bogani, K. Casarin, G. Cautero, G. Gaio, D. Giuressi, A. Gubertini, R.H. Menk, E. Quai, G. Scalamera, A. Vascotto ELETTRA, Basovizza, Italy L. Catani, D. Di Giovenale INFN-Roma II, Roma, Italy
	FERMI@Elettra is a linac-driven free-electron laser currently under commissioning at Sincrotrone Trieste, Italy. In order to protect the facility's permanent undulator magnets from radiation-induced demagnetization,beam losses and radiation doses are monitored closely by an active machine protection system. The talk focuses on the design and performance of its main diagnostic subsystems: Beam loss position monitors based on the detection of Cherenkov light in quartz fibers with multi-pixel photon counters, conventional ionization chambers with a new frontend electronics package, and solid-state RadFET dosimeters providing an online measurement of the absorbed dose in the undulator magnets.
	Slides TUOA04 [2.559 MB]

TUPD04	Diagnostics for the 150 MeV Linac and Test Transport Line of Taiwan Photon Source	linac, diagnostics, emittance, site	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.

TUPD06	Beam Diagnostic Overview of the SPIRAL2 RNB Section	ion, controls, target, ion-source	314
	C. Jamet, T.A. André, E. Guéroult, B. Jacquot, N. Renoux, A. Savalle, T. Signoret, F. Varenne, J.L. Vignet GANIL, Caen, France J.-M. Fontbonne LPC, Caen, France
	An extension to the existing GANIL facility in Caen, France is under construction. The new SPIRAL 2 construction will be realized in two phases, for the first phase the construction started in January 2011 and will consists of the accelerator buildings with two experimental facilities S3 and Neutrons for science (NFS). The second phase is the so called production building where radioactive ions are produced through the ISOL (Isotope Separation On Line) method. The produced radioactive ion beams (RIBs) will be extracted and accelerated up to 60keV from the ion sources, after beam purification the beam will be driven in the secondary beam lines either to a new experimental facility DESIR (Decay, excitation and storage of radioactive ions) constructed during the second phase of the new installation or the RIBs will be charge breed to form multi-charged ions that will be driven to the existing GANIL facility and post accelerated in the CIME cyclotron. This overview article gives a description of the secondary beam lines, the foreseen beam diagnostics which will allow tuning and controlling the radioactive ion beams in the secondary beam lines constructed in the SPIRAL2 Phase 2.

TUPD13	CLIC Drive Beam Position Monitor	damping, linac, luminosity, coupling	326
	S.R. Smith, A. Cappelletti, D. Gudkov, L. Søby, I. Syratchev CERN, Geneva, Switzerland S.R. Smith SLAC, Menlo Park, California, USA
	Funding: Work supported by Department of Energy contract DE-AC02-76SF00515 CLIC, an electron-positron linear collider proposed to probe the TeV energy scale, is based on a two-beam scheme where RF power to accelerate a high energy luminosity beam is extracted from a high current drive beam. The drive beam is efficiently generated in a long train at modest frequency and current then compressed in length and multiplied in frequency via bunch interleaving. The drive beam decelerator requires >40000 quadrupoles, each holding a beam position monitor (BPM). Though resolution requirements are modest (2 microns) these BPMs face several challenges. They must be compact and inexpensive. They must operate below waveguide cutoff to insure locality of position signals, ruling out processing at the natural 12 GHz bunch spacing frequency. Wakefields must be kept low. We find compact conventional stripline BPM with signals processed below 40 MHz can meet requirements. Choices of mechanical design, operating frequency, bandwidth, calibration, and processing algorithm are presented. Calculations of wakes and trapped modes and damping are discussed.

TUPD14	Commissioning of the Cavity BPM for the FERMI@Elettra FEL Project	cavity, FEL, undulator, polarization	329
	P. Craievich, T. Borden, A.O. Borga, R. De Monte, M. Ferianis, M. Predonzani ELETTRA, Basovizza, Italy M. Dal Forno, R. Vescovo DIEIT, Trieste, Italy
	The cavity Beam Position Monitor (BPM) is a fundamental beam diagnostic device that allows the measurements of the electron beam trajectory in a non-destructively way and with sub-micron resolution. Ten cavity BPM systems have been installed along the undulators chain in the FERMI@Elettra FEL1 project. In this paper we discuss the installation, commissioning and performance of these cavity BPM systems. We have carried out preliminary operations during a pre-beam period, such as the alignment and fine tuning of the RF cavities under vacuum. During the commissioning each BPM has been calibrated by mechanically moving the support on which the BPM is mounted. We have estimated the single shot resolution in presence of beam jitter by reading the beam position synchronously over many electron bunches from three or more BPMs. The algorithms have been subsequently improved, and the results are described.
	Poster TUPD14 [0.460 MB]

TUPD15	Technology Selection for the Beam Position Tuning System in Hadrontherapy Facilities	photon, high-voltage, controls, proton	332
	C. Belver-Aguilar, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós IFIC, Valencia, Spain E. Benveniste, M. Haguenauer, P. Poilleux LLR, Palaiseau, France
	Funding: CYCIT – IN2P3: AIC10-D-000518 The Beam Delivery System of some hadrontherapy facilities is characterized by having scanning magnets, which move the beam in order to irradiate all the tumor volume. To control the beam position, a Beam Position Monitor (BPM) is needed. The BPM described in this paper is a new type of BPM based on four scintillating fibers coupled to four photodiodes to detect the light produced by the fibers when intercepting the beam. We present here the study of the possible photodiodes able to read the light emitted by the scintillating fiber, and the tests performed in order to find the most suitable photodiode to measure the beam position from the variations in the beam current. The setup used for the tests comprises a Sr-90 source, which emits electrons, a scintillating fiber, converting these electrons into photons, and a photodiode, which detects the photons leaving the fiber. The photodiodes studied have been of two types: Avalanche Photodiode (APD) and Multi Pixel Photon Counter (MPPC). In this paper both photodiodes are compared and the results are presented.

TUPD17	Spatial Resolution Test of a BPMS for DESIREE Beam Line Diagnostics	ion, rfq, diagnostics, simulation	338
	S. Das, A. Källberg MSL, Stockholm, Sweden J. Harasimowicz The University of Liverpool, Liverpool, United Kingdom
	Funding: Two of us (S.Das and J. Harasimowicz) acknowledge the financial support received from the European Commission within FP7 Marie Curie Initial Training Network DITANET Spatial resolution of a beam profile monitoring system (BPMS) was tested. It will be a part of the DESIREE [1] diagnostics to monitor and cover the wide range of beam intensities and energies. The BPMS consists of an aluminum (Al) plate, a grid placed in front of Al, a microchannel plate (MCP), a fluorescent screen (F.S.), a PC, and a CCD camera [2]. A beam collimator containing a set of circular holes of different diameter and separation between them was built to check the spatial resolution of the system [3]. Two holes of diameter 1 mm, separated by 2 mm, in the collimator were used for this purpose. A proton beam was used for the measurements. It was observed that these holes create two beams of approximately same intensity of areas each of 1 mm in diameter with 2 mm separation between the beam centers on the screen, suggesting a resolution of 2 mm of the system. The resolution was tested for different beam energy (0.5-40 keV), and voltages applied on the Al and MCP plates. The experimental results will be compared with the simulations. [1] www.msl.se;www.atom.physto.se/Cederquist/desiree_web_hc.html [2] K. Kruglov et al, NIM A, 441, 595 (2002);Nucl. Phys. A, 701, 193c (2002) [3] S. Das et al, Proceedíngs of DITANET workshop, Nov. 23-25, 2009

TUPD19	Initial Tests of New Electron and Photon Beam Position Monitor Electronics at the Advanced Photon Source	photon, brilliance, injection, controls	344
	P. Leban I-Tech, Solkan, Slovenia G. Decker ANL, Argonne, USA
	Funding: Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by ANL, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357 Measurements were done at the Advanced Photon Source (APS) with Libera Brilliance+, connected to the small-aperture insertion device vacuum chamber pickup electrodes near the beamline 35-ID source point. A photoemission-based photon beam position monitor located 16.35 meters downstream of the center of the ID straight section was also monitored using Libera Photon electronics in horizontal/vertical configuration. Top-up injection transients were recorded simultaneously on both units, providing details about the electron and photon beam motions before, during, and after injection in the storage ring and beamline front end. FFT spectra from the APS-developed BSP-100 broadband BPM data acquisition electronics were compared with the Libera instruments. This article discusses the calibration procedure for electron and photon beam position monitors along with results of these measurements.

TUPD25	Design of Magnetic BPM and Error Corrections	simulation, shielding, vacuum, instrumentation	359
	M. Shafiee, E. Ebrahimi, S.A.H. Feghhi Shahid Beheshti University, Evin, Tehran, Iran
	For beam position monitoring (BPM) purposes, two prominent approaches as a physical effect have been applied including electrostatic and magnetic. In electrostatic types, secondary emission from the electrodes can be a problem when strong beam loss occurs, in such a situation, a magnetic BPM may be chosen. For this purpose we made a magnetic BPM including a square shape of ferromagnetic core with winding on each side. In this case study we used it for detecting the position of wire which is including a pulsed current (as an electron bunch) produced by a PROTEK G305 pulse generator. A Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of magnetic BPM. Measurement results have been compared with simulation using CST software and performed error corrections which are presented, with this regard we could measure the wire position with high resolution furthermore we deduced the wire position hasn’t linear relation with induced voltage and needs more physical and mathematical analyzing. This way propose us that we can use magnetic BPMs in this approach and calibrate them before installing on accelerators.
	Poster TUPD25 [0.120 MB]

TUPD26	Cavity-based Beam Diagnostics at ELSA	cavity, extraction, resonance, target	362
	T.R. Pusch, F. Frommberger, W. Hillert, B. Neff ELSA, Bonn, Germany
	Funding: Funded by DFG SFB/TR 16 Online monitoring of the intensity and position of an electron beam of a few hundred pA in the experiment beamlines at the ELSA facility is enabled by a system of resonant cavities. The position signal extracted from the resonators amounts to about 10^-19 W for 0.1 mm displacement at a beam current of 400 pA. It is separated from noise by phase-sensitive detection in a lock-in amplifier. The beam's position is obtained with a precision of one tenth of a millimeter, the signal strength being normalized by a beam current measurement with an uncertainty of a few pA. Via frequency mixing, the cavity signal of 1.5 GHz is converted down to a frequency below 100 kHz in order to be accepted by the amplifier, requiring a local oscillator stabilized by a feedback loop to 10^-6 precision. Details of the measurement system are presented.

TUPD28	Benchmarking the Performance of the Present Bunch Arrival Time Monitors at FLASH	pick-up, FEL, feedback, laser	365
	M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz DESY, Hamburg, Germany
	Funding: This work is partly supported by IRUVX-PP, an EU co-funded project under FP7 (Grant Agreement 211285) Presently, at FLASH four bunch arrival time monitors (BAM) are installed and in permanent operation. Moreover, they are incorporated in a longitudinal intra-bunch train feedback. In this paper, we present a review of the performance and the limitations of the current BAM design, based on the most recent machine studies. The detection principle of the monitor implements the electro-optical modulation of synchronised laser pulses. The RF and electro-optical front-ends are designed to be operated in a frequency band from DC up to 10 GHz. This allows for measuring the arrival time of each individual electron bunch at femtosecond resolution. The current design of the BAMs has been tested under the influence of disturbances on the arrival time measurement, such as variation of the bunch charge as well as deviation from the reference transverse bunch position. Those results will be incorporated in an upcoming design revision to upgrade the application and robustness of the BAMs.

TUPD30	Bunch Length Measurement using Coherent Cherenkov Radiation	laser, gun, linac, injection	368
	K. Kan, T. Kondoh, T. Kozawa, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultra-short electron bunches on the order of 100 fs or less can be used in the study of ultrafast reactions and phenomena in time-resolved pump-probe experiments involving the application of techniques such as pulse radiolysis. Such electron bunches are also useful for electro-magnetic (EM) radiation production, where the frequency of EM radiation depends on the electron bunch length. In this presentation, Coherent Cherenkov Radiation (CCR), which is a method of THz radiation emitted from relativistic electron bunches, was studied for a diagnostic of electron bunch length. A picosecond electron bunch generated by a photocahode radio frequency (RF) gun was used. CCR can emit narrow-band THz wave with a dielectric-lined waveguide structure. The intensity and frequency of CCR were measured by a Michelson interferometer and a 4.2K liquid-He cooled bolometer.

TUPD31	Measurement of the Slice Energy Spread Induced by a Transverse Deflecting RF Structure at FLASH	RF-structure, FEL, emittance, 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.

TUPD32	THz Radiation Diagnostics for Monitoring the Bunch Compression at the SwissFEL Injector Test Facility	radiation, vacuum, simulation, FEL	374
	C. Gerth, B. Schmidt, S. Wesch DESY, Hamburg, Germany R. Ischebeck, G.L. Orlandi, P. Peier, V. Schlott PSI, Villigen, Switzerland
	At the SwissFEL Injector Test Facility, installation of a magnetic chicane for longitudinal bunch compression is foreseen for the first half of 2011. Bunch compression will be accomplished by operating two S-band accelerating structures on-crest and two S-band structures at off-crest RF phases. An X-band structure for the linearization of the longitudinal phase space will be installed at a later stage. The detection of coherent synchrotron radiation or coherent diffraction radiation in the THz range can be used to monitor the bunch compression process and stabilize the RF phases by a beam-based feedback. In this paper, we study the source characteristics of the edge radiation emitted at the 4th dipole of the bunch compressor as well as the diffraction radiation generated by a metallic foil with a hole. Particle tracking simulations were used to model the bunch compression process for different operation modes. The performance of a bunch compression monitor consisting of focusing mirrors and band pass filters has been evaluated by simulating the THz radiation transport of the optical components.

TUPD33	Coherent Resonant Diffraction Radiation from Inclined Grating as a Tool for Bunch Length Diagnostics	radiation, diagnostics, vacuum, synchrotron	377
	L.G. Sukhikh, G. Kube DESY, Hamburg, Germany A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia V. Schlott PSI, Villigen, Switzerland
	There exists considerable interest in studying new types of non-invasive bunch length diagnostics for sub-picosecond bunches. In this context coherent Smith-Purcell radiation (CSPR) is a good candidate because the use of grating causes wavelength dispersive radiation emission, i.e. a CSPR based monitor does not require any additional spectrometer. In contrast to existing CSPR monitors a new scheme is proposed with two detectors placed at fixed positions, and a wavelength scan is performed by scanning the tilt angle between grating surface and beam axis. In this scheme the information of both detectors, positioned opposite to each other and perpendicular to the beam axis, can be combined by taking the intensity ratio of the signals from both detectors. The advantage of such diagnostics scheme is that one has not to rely on absolute values of the radiation yield, avoiding the need to know the sensitivity of each detector with high accuracy. In contrast to CSPR which is emitted from a grating oriented parallel to the beam, the effect is termed coherent resonant diffraction radiation when the grating is tilted. In the report we present simulation results and detailed experimental plan.

TUPD36	Progress and Status of the Laser-based Synchronization System at FLASH	laser, FEL, feedback, status	383
	S. Schulz, M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, F. Ludwig, S. Ruzin, H. Schlarb, B. Schmidt DESY, Hamburg, Germany
	Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285). The free-electron lasers FLASH and European XFEL demand a high timing accuracy between the electron bunches and external laser systems for both exploitation of the short VUV and X-ray pulses in time-resolved pump-probe experiments and seeded operation modes. The required precision can only be achieved with laser-based synchronization schemes. The prototype system installed at FLASH is continuously evolving and subject to improvements. In this paper, we give an overview on the present status, report on the latest developments and extensions, and discuss future challenges. Particularly, the recent move to a new type of master laser oscillator led to a significant enhancement of the robustness and reliability. Consequently, research can focus on the implementation of the electron bunch arrival time feedback, new technologies for timing distribution and integration of Ti:sapphire lasers into the optical synchronization system.

TUPD38	Design of a Single-Shot Prism Spectrometer in the Near- and Mid-Infrared Wavelength Range for Ultra-Short Bunch Length Diagnostics	simulation, radiation, diagnostics, optics	386
	C. Behrens DESY, Hamburg, Germany A.S. Fisher, J.C. Frisch, A. Gilevich, H. Loos, J. Loos SLAC, Menlo Park, California, USA
	The successful operation of high-gain free-electron lasers (FEL) relies on the understanding, manipulation, and control of the parameters of the driving electron bunch. Present and future FEL facilities have the tendency to push the parameters for even shorter bunches with lengths below 10 fs and charges well below 100 pC. This is also the order of magnitude at laser-driven plasma-based electron accelerators. Devices to diagnose such ultra-short bunches even need longitudinal resolutions smaller than the bunch lengths, i.e. in the range of a few femtoseconds. This resolution is currently out of reach with time-domain diagnostics like RF-based deflectors, and approaches in the frequency-domain have to be considered to overcome this limitation. Our approach is to extract the information on the longitudinal bunch profile by means of infrared spectroscopy using a prism as dispersive element. In this paper, we present the design considerations on a broadband single-shot spectrometer in the near- and mid-infrared wavelength range (0.8 - 39.0 μm).

TUPD41	The Beam Halo Monitor for FLASH	diagnostics, laser, free-electron-laser, radiation	395
	A. Ignatenko, N. Baboi, O. Hensler, M. Schmitz, K. Wittenburg DESY, Hamburg, Germany H.M. Henschel, W. Lange DESY Zeuthen, Zeuthen, Germany A. Ignatenko, W. Lohmann BTU, Cottbus, Germany S. Schuwalow University of Hamburg, Hamburg, Germany
	The Beam Halo Monitor (BHM) for FLASH based on pCVD diamond and monocrystalline sapphire sensors has been successfully commissioned and is in operation. It is a part of the beam dump diagnostics system that ensures safe beam dumping. The description of the BHM and experience gained during its operation are given in this paper.

TUPD43	XFEL Beam Loss Monitor System	beam-losses, undulator, controls, high-voltage	401
	A. Kaukher, I. Krouptchenkov, B. Michalek, D. Nölle, H. Tiessen DESY, Hamburg, Germany
	European XFEL will have a sophisticated Machine Protection System, part of which - Beam Loss Monitors(BLM). The monitors will detect losses of electron beam, in order to protect the components of the XFEL from damage and excessive activation. For protection of undulators, BLMs with a scintillator bar will be used. BLMs at places with high radiation load will be equipped with fused silica rods. Beam dumps of the XFEL will be instrumented with glass-fiber BLMs. The BLMs were tested with an electron test-beam at DESY, as well as at FLASH. Due to large amount of light produced by scintillator and high gain of the used photomultiplier, no optical grease is needed in front of the photomultiplier' window, while typical cathode voltage is only 500-600 volt. The prototype with quartz glass was typically operated at higher cathode voltage. Good operation of all three types of BLMs prototypes was obtained. It is planned to use same monitors also for the FLASH2 project. Current status of the XFEL BLM system development will be presented.

TUPD48	Transition Radiation from a Cylindrical Target and Transverse Beam Size Diagnostics	target, radiation, optics, FEL	410
	A. Potylitsyn TPU, Tomsk, Russia L.G. Sukhikh DESY, Hamburg, Germany
	For modern X-ray FELs like LCLS in SLAC, FLASH in DESY and constructed ones like European X-FEL the transverse beam profile diagnostics using well-known optical Transition Radiation (TR) is not a trivial task because of a short bunch length and instabilities. Due to these reasons a bunch emits any kind of radiation coherently that makes it impossible to determine transverse profile of such bunch. One may use radiation with wavelengths shorter than bunch length (e.g. EUV) to avoid the problem of radiation coherence. Because of a high quality of mirrors in that region needed to construct proper optical line we propose to use a cylindrical target instead of flat one. TR generated by the cylindrical target is wider than the one from the flat target. But in this case the radiation generated by particles with different impact-parameters relative to a cylinder axes depends on the point of interaction. Proper choice of cylinder parameters allows to obtain beam profile image without any additional optics. In this report we present the simulation results and show how the radiation from the cylindrical target may be used for the bunch transverse profile diagnostics with good space resolution.

TUPD50	Slice-Emittance Measurements at ELBE / SRF-Injector	emittance, 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.

TUPD51	Ionization Profile Monitors - IPM @ GSI	high-voltage, ion, synchrotron, space-charge	419
	T. Giacomini, P. Forck GSI, Darmstadt, Germany J.G. De Villiers iThemba LABS, Somerset West, South Africa J. Dietrich FZJ, Jülich, Germany D.A. Liakin ITEP, Moscow, Russia
	The Ionization Profile Monitor in the SIS18 is frequently used for machine development. The permanent availability and the elaborated software user interface make it easy and comfortable to use. Additional to the beam profile data the device records the data of synchrotron dc current, dipole ramp and accelerating rf properties. The trend curves of these data are shown correlated to the beam profile evolution for a full synchrotron cycle from injection to extraction with 100 profiles/s. The reliable function is based on the optimized in-vacuum hardware design, like the stable high voltage connections, the electric field box with very uniform field distribution and the uv-light based calibration system. The permanent availability is based on the convenient software interface using the Qt library. A new IPM generation was recently commissioned in the experimental storage ring ESR at GSI and one in the COSY ring at FZ-Jülich. These monitors are enhancements of the SIS18 multiwire IPM but equipped with an especially developed large area 50x100 mm² optical particle detector of rectangular shape that is readout by a digital camera through a viewport.

TUPD53	A Low-Power Laser Wire with Fiber Optic Distribution	laser, diagnostics, scattering, pick-up	425
	R.B. Wilcox, J.M. Byrd, M.S. Zolotorev LBNL, Berkeley, California, USA V.E. Scarpine Fermilab, Batavia, USA
	Funding: This work was supported by the US Department of Energy under contract DE-AC02-05CH11231. Laser-based position diagnostics for hydrogen ion (H⁻) beams typically use high power optical pulses that must be transported via free space to the diagnostic point. It is difficult to maintain stable alignment through such systems, especially when multiple channels are required. We describe a method for distributing low power, amplitude modulated pulse trains via fiber optic, and detecting interaction with the H⁻ beam by synchronous detection of the stripped electrons. Trains of 10 ps, 10⁶⁴ nm pulses at 400 MHz repetition rate are modulated by a 1 MHz signal that is the reference for a lockin amplifier. The average beam power is below one Watt. Synchronous detection at RF frequencies allows for efficient noise rejection when using optical powers below the nonlinear (Raman scattering) threshold of an optical fiber. The laser is synchronized with the bunch repetition rate, so the diagnostic can be used for bunch length measurements as well. We present results of tests of the optical system with 10⁰ m, single-mode fiber and realistic detected signal levels, demonstrating detection of the modulation signal with high signal-to-noise ratio and low nonlinearity.

TUPD54	Comparison of Different Radiators used to Measure the Transverse Characteristics of Low Energy Electron Beams at PITZ	cathode, laser, radiation, FEL	428
	S. Rimjaem, G. Asova, J.W. Bähr, H.-J. Grabosch, M. Gross, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M.A. Khojoyan, G. Klemz, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko, S. Weidinger DESY Zeuthen, Zeuthen, Germany D. Richter HZB, Berlin, Germany
	The photoinjector test facility at DESY, Zeuthen site (PITZ), has been established for developing and optimizing electron sources for linac based Free Electron Lasers (FELs). Characterizations of electron beams with maximum energies of about 25 MeV are carried out at PITZ. In order to study properties of electron beams, several diagnostic systems are applied. One of the important investigations is the study of transverse beam profiles at different beam conditions. Three screen types -YAG powder coated, optical transition radiation (OTR), and CVD-diamond screen- are used as beam profile monitors and are installed in screen stations at different locations along the beam transport line. In addition, wire scanner systems are available in the beamline for the same purpose. In this contribution a comparison of measurement results from all three screen types and the wire scanner used to characterize long pulse trains will be presented and discussed.
	Poster TUPD54 [0.193 MB]

TUPD55	Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN	vacuum, instrumentation, impedance, dipole	431
	D. Egger EPFL, Lausanne, Switzerland A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca CERN, Geneva, Switzerland
	The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.
	Poster TUPD55 [0.959 MB]

TUPD59	Suppression of Coherent Optical Transition Radiation in Transverse Beam Diagnostics by Utilising a Scintillation Screen with a Fast Gated CCD Camera	simulation, laser, FEL, linac	440
	M. Yan Uni HH, Hamburg, Germany C. Behrens, C. Gerth, G. Kube, B. Schmidt, S. Wesch DESY, Hamburg, Germany
	Micro-bunching instabilities in high-brightness beams of linac-driven FELs can lead to coherence effects in the emission of optical transition radiation (OTR) used for standard transverse profile diagnostics, thus rendering it impossible to observe a direct image of the particle beam. By using a scintillation screen in combination with a fast gated CCD camera, coherence effects can be suppressed as OTR is created in an instantaneous process while scintillation light has a certain decay time. In addition, the emission of the scintillation light is a statistical process from many atoms which is completely insensitive to the longitudinal bunch structure and does not produce coherence effects. Gating the camera during the passage of the electron bunch should eliminate any influence of the coherent OTR (COTR). First experiments using this method have been performed successfully at FLASH as a proof-of-principle. In this paper, we study the applicability of scintillation screens for high-energy electron beams under operation conditions for which COTR is emitted. Experimental results together with simulations are presented and discussed in view of COTR suppression and spatial resolution.

TUPD63	Gas Electron Multipliers for the Antiproton Decelerator	vacuum, antiproton, cathode, high-voltage	449
	S.C. Duarte Pinto, O.R. Jones, L. Ropelewski, J. Spanggaard, G. Tranquille CERN, Geneva, Switzerland
	The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light (~0.4% X₀), and measures horizontal and vertical profiles directly in one plane. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPCs) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another 3 detectors now installed in the ASACUSA beam line. This paper will provide a detailed description of the detector and discuss the initial results obtained.

TUPD68	Feasibility Study for a Single-Shot 3D Electron Bunch Charge Distribution Monitor with a Polarized Probe Laser at SPring-8 Photoinjector	laser, polarization, gun, monitoring	464
	Y. Okayasu, H. Dewa, H. Hanaki, S. Matsubara, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan T. Ishikawa RIKEN Spring-8 Harima, Hyogo, Japan A. Maekawa, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
	It is essential for precise characterizations of light sources to monitor ever-changing charge distribution of electron bunch by single-shot measurement with high resolutions. Therefore, a single-shot and non-destructive 3D bunch charge distribution (BCD) monitor was developed to characterize longitudinal and transverse BCDs simultaneously. It is based on Electro-Optical (EO) multiple sampling with a manner of spectral decoding. For the transverse detection, eight EO-crystals surround the beam axis azimuthally, and a linear-chirped probe laser pulse with a hollow shape and spirally temporal shift, passes through the EO-crystals. A principle verification experiment has been successfully carried out with two EO-crystals in our facility. In addition, we are promoting a numerical calculation of the ultra-short and radial polarized laser transportation for our own system assuming eight EO-crystals usage in order to confirm observation feasibility. We report the principle and the first experimental results of the novel 3D-BCD monitor and introduce the feasibility demonstration with a calculation about a propagation of transverse polarization distributions along probe laser optics.
	Poster TUPD68 [4.684 MB]

TUPD76	Vibration and Beam Motion Diagnostics in TLS	photon, status, diagnostics, monitoring	485
	Y.K. Chen, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo NSRRC, Hsinchu, Taiwan
	High beam stability is essential in a modern synchrotron light source due to small emittance. Beam motion caused by various factors should be remedy by various approaches to achieve high beam stability. Vibration will deteriorate beam stability and need considered as a part of beam diagnostic. An integrated environment for beam orbit and vibration monitoring systems were set up for various studies. Implementation details and some beam observation will be presented in this report.
	Poster TUPD76 [2.750 MB]

TUPD78	SOLEIL Beam Orbit Stability Improvements	photon, feedback, kicker, synchrotron	488
	N. Hubert, L. Cassinari, J.-C. Denard, P. Lebasque, L.S. Nadolski, D. Pédeau SOLEIL, Gif-sur-Yvette, France
	SOLEIL beam orbit stability is being significantly improved. A first effort was set on long term stability for specific beamlines (new 160 m long Nanoscopium and Hard X-rays beamlines). BPM and XBPM steel supports will be replaced for reducing their sensitiveness to temperature drift. Thermal expansion of INVAR and fused Silica stands has been measured. INVAR has been selected for the new BPM supports. A second effort aimed at improving the orbit stability of beamlines based on bending magnets. We plan to use their first XBPM in the global orbit feedback loops (slow and fast). For that purpose new XBPM electronics called Libera photons will be used. Soleil, having contributed to the development, tested extensively the first series. A third effort focused on noise source location. An application developed in-house has identified localized orbit perturbation sources introducing spurious spectrum lines at 46, 50 and 54 Hz on the orbit. They originate from fans rotating close to ceramics chambers of kickers, FCT and shaker. Their suppression decreases the vertical integrated noise down to 300 nm in the DC-500Hz frequency range.

TUPD85	Photoinjector Based MeV Electron Microscopy	gun, emittance, 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.

TUPD88	A Micro-Channel Plate Based RFA Electron Cloud Monitor for the ISIS Proton Synchrotron	gun, proton, synchrotron, diagnostics	512
	A. Pertica, S.J. Payne STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	Electron clouds produced inside a particle accelerator vacuum chamber by the passage of the beam can compromise the operation of the accelerator. The build up of electron clouds can produce strong transverse and longitudinal beam instabilities which in turn can lead to high levels of beam loss often requiring the accelerator to be run below its design specification. To study the phenomena of electron clouds at the ISIS Proton Synchrotron, a Micro-Channel Plate (MCP) based electron cloud detector has been developed. The detector is based on the Retarding Field Analyser (RFA) design and consists of a retarding grid, which provides energy analysis of the electron signal, and a MCP assembly placed in front of the collector plate. The MCP assembly provides a current gain over the range 300 to 25K, thereby increasing the signal to noise ratio and dynamic range of the measurements. In this paper, we describe the lab based experiment used to test our detector using a low energy electron gun. Results from our MCP based detector installed in the ISIS accelerator ring are discussed and compared to a RFA detector, installed at the same location, which has no MCP fitted.
	Poster TUPD88 [1.793 MB]

TUPD89	Polarimetry of 0.1 – 130 MeV Electron Beams at the S-DALINAC*	laser, polarization, linac, photon	515
	C. Eckardt, P. Bangert, R. Barday, U. Bonnes, R. Eichhorn, J. Enders, C. Ingenhaag, Y. Poltoratska, M. Wagner TU Darmstadt, Darmstadt, Germany
	Funding: * Work supported by DFG through SFB 634 and by the state of Hesse through the Helmholtz International Center for FAIR in the framework of the LOEWE program. A source of polarized electrons[1] has been installed at the superconducting 130 MeV Darmstadt electron linear accelerator S-DALINAC[2], augmenting the experimental program for nuclear structure studies and fundamental experiments. Polarized electrons from a strained-superlattice GaAs cathode are electrostatically accelerated to 100 keV. In the low-energy beam line the beam parameters are measured using diagnostic elements like wire scanners and RF-monitors, a Wien filter for spin manipulation and a 100 keV Mott polarimeter for polarization measurement. Following a superconducting accelerator section, electron beams with 5-10 MeV energy are used for bremsstrahlung experiments. Here, the absolute degree of polarization will be measured using a Mott polarimeter, while monitoring the beam polarization during the experiment with a Compton transmission polarimeter. Alternatively, the electron beam can be further accelerated in the recirculating superconducting main linac. For beam energies of 50-130 MeV a Moeller polarimeter as well as two Compton transmission polarimeter are foreseen. We report on the performance of the polarized source and the polarimeter design and installation. [1] C. Eckardt et al., IPAC 10, Kyoto, _{_}THPEC019_{_}, p 4083. [2] A. Richter, Proc. EPAC 96, Sitges, _{_}WEX02A_{_}, p.110.

TUPD93	Diagnostics of RF Breakdowns in High-Gradient Accelerating Structures	collider, plasma, vacuum, linear-collider	527
	A. Palaia Uppsala University, Uppsala, Sweden V.A. Dolgashev, J.R. Lewandowski, S.P. Weathersby SLAC, Menlo Park, California, USA
	Within the framework of the research on high-gradient accelerating structures for future linear colliders, diagnostics of radio-frequency (RF) breakdowns is of great importance to support the understanding of the vacuum breakdown process. Measurements of RF and electron and ion currents emitted during and after a breakdown can be used to calculate the properties of any objects responsible for such power reflection and charge emission. Possible breakdown models, breakdown localization and a time-scale of the process are here discussed and compared to dedicated measurements. First results are presented.
	Poster TUPD93 [7.029 MB]

TUPD97	Diagnostic System of TAC IR FEL Facility	FEL, emittance, 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, emittance, diagnostics	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]

WEOA02	Experimental Investigations of Backward Transition Radiation from Flat Target in Extreme Ultraviolet Region	radiation, target, diagnostics, FEL	544
	L.G. Sukhikh, G. Kube DESY, Hamburg, Germany D. Krambrich, W. Lauth IKP, Mainz, Germany Yu.A. Popov, A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia
	Forward transition radiation in X-ray range and backward transition radiation (BTR) in optical spectral region are investigated in details due to their use for purposes of particle and beam diagnostics. In order to improve diagnostics tools we proposed to use BTR in extreme ultraviolet (EUV) region [,], where theoretical models are existing only. We performed experimental investigations of BTR characteristics in EUV spectral region generated by a molybdenum target at 855 MeV electron beam of the MAMI-B (Mainz, Germany). Angular patterns and intensities of BTR both in optical and EUV regions for different observation angles were investigated. The measured intensity of optical BTR agrees with a theory with reasonable accuracy but one in EUV region is more intense than theoretically predicted. Our experimental estimation of the experimental BTR yield in EUV region is (2.4/3.6)•10⁻⁴ photons/electron and this is more than 4 / 6 times higher than the theoretical value. L.G. Sukhikh, S.Yu.Gogolev and A.P.Potylitsyn, Nucl. Instrum. Methods Phys. Res., Sect. A 623, 567 (2010) ** L.G. Sukhikh, S.Yu.Gogolev and A.P.Potylitsyn, J. Phys.: Conf. Ser. 236, 012011 (2010).
	Slides WEOA02 [6.967 MB]

WEOA03	Detailed Experimental Characterization of an Ionization Profile Monitor	extraction, ion, space-charge, target	547
	J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou CEA, Gif-sur-Yvette, France F. Becker, P. Forck, B. Walasek-Höhne GSI, Darmstadt, Germany J. Marroncle CEA/DSM/IRFU, France
	Funding: Marie Curie Fellowship by the EU In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.
	Slides WEOA03 [1.964 MB]

WEOB01	Scintillating Screen Applications in Beam Diagnostics	ion, diagnostics, photon, scattering	553
	B. Walasek-Höhne GSI, Darmstadt, Germany G. Kube DESY, Hamburg, Germany
	Scintillation screens are widely used for transverse beam profile diagnostics at particle accelerators. The monitor principle relies on the fact that a charged particle crossing the screen material will deposit a part of its energy which is converted to visible light. The resulting light spot is a direct image of the two-dimensional beam distribution and can be measured with standard optical techniques. Scintillating screen monitors were mainly deployed in hadron and low energy electron machines where the intensity of optical transition radiation (OTR) is rather low. The experience from modern linac based light sources showed that OTR diagnostics might fail even for high energetic electron beams, thus making the use of scintillators again very attractive. This contribution summarizes results and trends from "Scintillating Screen Applications in Beam Diagnostics" workshop recently held in Darmstadt. In the first part an introduction to the scintillation mechanism will be given, including demands and limitations as e.g. the dynamic range and saturation. Thereafter a brief overview on actual screen monitor applications at electron and hadron accelerators will be presented.
	Slides WEOB01 [14.721 MB]

WEOB02	Experimental Comparison of Performance of Various Fluorescent Screens Applied for Relativistic Electron/Positron Beam Imaging	positron, diagnostics, booster, laser	558
	O.I. Meshkov, V.A. Kiselev, D.P. Sukhanov, A.N. Zhuravlev BINP SB RAS, Novosibirsk, Russia V.L. Dorokhov, V.V. Smaluk BINP, Novosibirsk, Russia E.N. Galashov Nikolayev Institute of Inorganic Chemistry, Novosibirsk, Russia
	Fluorescent screens are widely used for single-pass measurements of transverse beam profile at most of accelerator facilities. Great number of materials is now used for manufacture of fluorescent screens. The linearity, sensitivity and spatial resolution of the diagnostics depend on the choice of screen substance. We made an attempt to compare a linearity and relative light yield for few types of the fluorescent materials applied for screen manufacturing. A CCD-camera and photomultiplier tube record the light flux and 2D profile of the electron/positron beam image on the screen. Experiments were carried out with the electron/positron beam energy of 350 MeV and the beam charge of 0.1 – 100 pC.
	Slides WEOB02 [3.454 MB]

WEOD01	Beam Induced Fluorescence Monitors	ion, photon, diagnostics, proton	575
	F. Becker GSI, Darmstadt, Germany
	Non-intercepting diagnostic devices in hadron accelerators offer continuous online monitoring capability. They also avoid the problem of potential thermal damage in high-current applications. Taking advantage of the residual gas as active material, the Beam Induced Fluorescence (BIF) monitor exploits gas fluorescence in the visible range for transversal profile measurements. Depending on beam parameters and vacuum-constraints, BIF monitors can be operated at base-pressure or in dedicated local pressure bumps up to the mbar range. Nowadays, BIF monitors are investigated in many accelerator laboratories for hadron energies from about 100 keV up to several 100 GeV. This talk gives an introduction to the measurement principle and typical operating conditions. It summarises recent investigations, e.g. on different working gases, and it compares various technical realisations.
	Slides WEOD01 [12.701 MB]

Paper

Title

Other Keywords

Page

MOOB02

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

emittance, 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]

MOOB03

Diamond-based Beam Halo Monitor Equipped with RF Fingers for SACLA

wakefield, simulation, vacuum, radiation

12

H. Aoyagi, T. Aoki, T. Bizen, K. Fukami, N. Nariyama, S. Suzuki
JASRI/SPring-8, Hyogo-ken, Japan
Y. Asano, T. Itoga, H. Kitamura, T. Tanaka
RIKEN/SPring-8, Hyogo, Japan

Funding: This work is partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (c) 21604017.
The diamond-based beam halo monitor has been developed for SPring-8 Angstrom Compact free electron LAser (SACLA). This monitor is an interlock sensor to protect the undulator magnets against radiation damage. Pulse-mode measurement is adopted to suppress the background noise efficiently. The diamond detectors are dipped into the beam duct in order that the intensity of the beam halo can be measured directly. However, it is important issue to avoid degradation in quality of electron beam for SPring-8 XFEL. We designed new RF fingers with aluminum windows in order to reduce the impedance to the beam. The RF fingers are made of beryllium copper, and having the aluminum windows, which is low-Z material, in front of active areas of the diamond detectors. Therefore, the influence of secondary electrons and bremsstrahlung from the finger material can be suppressed. To evaluate influence on the output signal of the diamond detector by changing the finger material, both the simulation study and the experimental measurement have been carried out. Feasibility tests of this monitor, which is equipped with the RF fingers, have also been demonstrated at the SCSS test accelerator.

Slides MOOB03 [1.353 MB]

MOPD04

RHIC Electron Lens Test Bench Diagnostics

ion, diagnostics, gun, solenoid

38

D.M. Gassner, E.N. Beebe, W. Fischer, X. Gu, K. Hamdi, J. Hock, C. Liu, T.A. Miller, A.I. Pikin, P. Thieberger
BNL, Upton, Long Island, New York, USA

An Electron Lens system will be installed in RHIC to increase luminosity by counteracting the head-on beam-beam interaction. The proton beam collisions at the two experimental locations will introduce a tune spread due to a difference of tune shifts between small and large amplitude particles. A low energy electron beam will be used to improve luminosity and lifetime of the colliding beams by reducing the betatron tune shift and spread. In preparation for the Electron Lens installation next year, a test bench facility will be used to gain experience with all sub-systems. This paper will discuss the diagnostics related to measuring the electron beam parameters.

MOPD09

Electron Beam Diagnostics for FLASH II

diagnostics, undulator, radiation, laser

53

N. Baboi, D. Nölle
DESY, Hamburg, Germany

Up to now, the FLASH linac serves one SASE (Self-Amplified Spontaneous Emission) undulator. The radiation produced can be guided to one of 5 beamlines in the experimental hall. In order to increase the availability of the machine, an extension, FLASH II, will be built in the next few years. A second undulator section will be built to generate SASE light. A HHG (High Harmonic Generation) laser will alternatively be used to produce seeded radiation in the undulators. The electron beam diagnostics in FLASH II has to enable the precise control of the beam position, size, timing, as well as the overlap of the electron beam with the HHG laser. The losses have to be kept under control, and the beam has to terminate safely in the beam dump. In comparison to FLASH, which was designed to run with rather high charge, the dynamic range of the diagnostics has to be between 0.1 to 1 nC, similar to the European XFEL. This paper gives an overview of the diagnostics for FLASH II.

MOPD14

Calibration of the Electrostatic Beam Position Monitors for VEPP-2000

vacuum, pick-up, optics, positron

68

Yu. A. Rogovsky, I. Nesterenko
BINP SB RAS, Novosibirsk, Russia

The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.

Poster MOPD14 [0.393 MB]

MOPD17

Beam-based HOM Study in Third Harmonic SC Cavities for Beam Alignment at FLASH

HOM, cavity, dipole, polarization

77

P. Zhang, R.M. Jones, I.R.R. Shinton
UMAN, Manchester, United Kingdom
N. Baboi, B. Lorbeer, P. Zhang
DESY, Hamburg, Germany
H. Ecklebe, T. Flisgen, H.-W. Glock
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by European Commission under the FP7 Research Infrastructures grant agreement No.227579.
An electron beam entering an accelerator cavity excites higher order modes (HOM). These are radiated to HOM couplers, subsequently damped, and can also be used to facilitate beam monitoring. The modes which deflect the beam transversely are the focus of this study and are used to monitor the beam position. Results are presented on the first analysis of beam alignment based on HOM signals from the third harmonic cavities at FLASH. The electrical center of each mode is ascertained by moving the beam to minimize the HOM signal detected. A single electron bunch per RF pulse is used.

MOPD20

Applicability of the AM-PM Conversion Method to Beam Position Monitoring of Electron Beams accelerated in S-Band Frequency Range

pick-up, insertion, controls, monitoring

86

M. Ruf, P. Quednau, L. Schmidt
U. Erlangen-Nurnberg LHFT, Erlangen, Germany
S. Setzer
Siemens Med, Erlangen, Germany

Funding: Work supported by Bayerische Forschungsstiftung in the project "MEDieMAS - Effiziente Bestrahlungsgeräte für Krebstherapie (Efficient radiation systems for cancer therapy)", file number AZ-735-07
In this paper, the applicability of the amplitude-to-phase-conversion (AM-PM) method to beam position monitoring (BPM) purposes in S-Band frequency range is investigated. The proof-of-principle experiment is done by AM-PM-processing of capacitive pickup signals generated by a 6 MeV S-Band electron beam. It is demonstrated that the AM-PM-output pulsed DC signal is proportional to transverse beam offsets. Furthermore, design considerations and selection criteria of appropriate RF devices are described. Additionally, results of cold measurements of a planar 2-channel AM-PM-receiver module are presented indicating that the applicability will also be given for even higher frequency ranges.

MOPD27

A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI

pick-up, ion, vacuum, impedance

107

F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick
GSI, Darmstadt, Germany
Yu.A. Litvinov
MPI-K, Heidelberg, Germany
M.S. Sanjari
IKF, Frankfurt am Main, Germany
J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao
IMP, Lanzhou, People's Republic of China

A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD31

Future Timing and Synchronization Scheme at ELBE

laser, radiation, gun, controls

116

M. Kuntzsch, A. Büchner, T. Kirschke, U. Lehnert, F. Röser
HZDR, Dresden, Germany

The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf is currently extended to offer capacity for new experiments. The reconstruction includes the setup of a THz-beamline with a dedicated user laboratory and a beamline for electron-beam - high-power laser experiments. The current synchronization scheme offers stability to the picoseconds level. The new experiments require a femtosecond synchronization in order to get field-strength resolved THz-probes and to have a stable overlap between the electron-bunches with the laser pulses. In the future there will be a MIT/DESY-like system [1] with a pulsed fiber laser as an optical reference oscillator. The laser pulses will be distributed over stabilized fiber links to the remote stations. Later on it is planned to install EOM-based beam arrival time monitors (BAMs) in order to monitor the bunch jitter and to establish a feedback system to reduce the jitter. Besides that, the timing system has to be revised to trigger experiments with low repetition rate, two guns (thermionic DC, superconducting RF) and lasers. The Poster will show the Layout of the possible future Timing and Synchronization System at ELBE.
[1] J. Kim, J.A. Cox, J.J. Chen, F.X. Kärtner, "Drift-free femtosecond timing synchronization of remote optical and microwave sources", Nature Photonics, Vol. 2, pp. 733-736 (2008).

MOPD33

Pickup Design for a High Resolution Bunch Arrival Time Monitor for FLASH and XFEL

pick-up, simulation, vacuum, laser

122

A. Angelovski, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb
DESY, Hamburg, Germany
J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Electron Laser in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAM’s) which are part of the optical synchronization system [1-2]. FLASH usually works with bunch charges of 0.2 to 1 nC, but for a variety of future experiments, the system needs to operate with bunch charges in the range of 10 to 20 pC. Below 0.2 nC the sensitivity of such a BAM scales approximately linearly with the bunch charge and therefore the system no longer fulfills the time resolution requirements for these low charges. For the low bunch charge regime operation, the bandwidth has to be increased substantially. This paper shows a new design of a high frequency button pickup that can operate in a frequency band from DC up to 40 GHz. The design criteria of the pickup are the voltage slope steepness at the zero-crossing, the maximum amplitude and the ringing of the picked-up voltage. The performance of the designed model is analyzed for fabrication tolerances and orbit variations. Some manufacturing and practical issues are discussed and solutions are offered for improving the results. A full wave simulation with CST PARTICLE STUDIO is performed in order to prove the concept.
[1] F. Loehl et. al.,“A Sub 100 fs Electron Bunch Arrival-time Monitor System for FLASH”, THOBFI01, EPAC 2006
[2] F. Loehl et. al.,“A Sub-50 Femtosecond bunch arrival time monitor system for FLASH”, WEPB15, DIPAC 2007

Poster MOPD33 [27.661 MB]

MOPD34

Analysis of New Pickup Designs for the FLASH and XFEL Bunch Arrival Time Monitor System

pick-up, simulation, laser, vacuum

125

A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp
TU Darmstadt, Darmstadt, Germany
M.K. Bock, M. Bousonville, P. Gessler, H. Schlarb
DESY, Hamburg, Germany
J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Electron Laser in Hamburg (FLASH) is equipped with Bunch Arrival time Monitors (BAM)[1], which provide for a time resolution of less than 10 fs for bunch charges higher than 0.2 nC. Future experiments, however, will aim at generating FEL light pulses from bunch charges of 10-20 pC. The sensitivity of the measurement system is defined by the slope of the pickup signal at the zero crossing and scales close to linear with the bunch charge. The requirements on the time resolution will no longer be fulfilled when operating at decreased bunch charges. Several designs have been developed in CST PARTICLE STUDIO®, each having an increased bandwidth larger than 40 GHz for meeting the requirements when operating at low bunch charges. Furthermore, new post-processing functions for the automatic evaluation of the signal slope and the ringing in the detected voltage signal have been developed and implemented within the CST software for defining optimization goals of the built-in optimizer for determining free design parameters. Results of the new designs are presented and compared with the current BAM pickup.
[1] M.K. Bock et.al., "Recent Developments of the Beam Arrival Time Monitor with Femtosecond Resolution at FLASH", WEOCMH02, IPAC 2010

Poster MOPD34 [3.112 MB]

MOPD38

1-MHz Line Detector for Intra-bunch-train Multichannel Feedback

laser, radiation, feedback, diagnostics

137

L. Kotynia, D.R. Makowski, A. Mielczarek, A. Napieralski
TUL-DMCS, Łódź, Poland
C. Gerth, T. Jezynski, H. Schlarb, B. Schmidt, B. Steffen
DESY, Hamburg, Germany

Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285).
The measurement and control of the electron bunch length is one of the key diagnostics in linac-based free-electron lasers to reach the required peak current in the electron bunches. In order to use the multi-channel signals from longitudinal bunch shape measurements for intra train feedback for the European XFEL, line readout rates in the MHz range and low latencies are required, which is far more than commercial multichannel radiation detectors (line cameras) can provide. The paper presents a 256 channel detector that allows analyzing optical or infrared radiation with 1 MHz rate and a few microseconds latency using photodiode arrays, as needed for synchrotron light monitors, electro-optical bunch length measurements, or other laser based diagnostics. The proposed architecture aims at high frequency readout with low latency by using a multichannel electronic front-end designed for HEP, combined with Si or InGaAs detector arrays with very fast response time, and a low-latency data acquisition system. Currently the device is at the conceptual design stage.

Poster MOPD38 [3.262 MB]

MOPD40

Beam Measurements with Visible Synchrotron Light at VEPP-2000 Collider

controls, collider, diagnostics, positron

140

Yu. A. Rogovsky, D.E. Berkaev, I. Koop, A.N. Kyrpotin, I. Nesterenko, A.L. Romanov, Y.M. Shatunov, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia

This paper describes beam diagnostics at VEPP-2000 collider, based on visible synchrotron light analysis. These beam instruments include: SR beamline and optics; acquisition tools and high resolution CCD cameras distributed around the storage ring to measure the transverse beam profile and its position in vacuum chamber; photomultiplier tubes (PMT) which enables beam current measurements. Some applications of these measurement systems and their measurement results are presented.

Poster MOPD40 [0.599 MB]

MOPD45

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

ion, emittance, 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.

MOPD48

Optical Electron Beam Diagnostics for Relativistic Electron Cooling Devices

laser, scattering, photon, diagnostics

158

T. Weilbach
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany
J. Dietrich
FZJ, Jülich, Germany

New magnetized high energy coolers like the one proposed for the High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) have specific demands on the diagnostic of the electron beam. Due to high voltage breakdowns they only allow a very small beam loss so non-invasive beam diagnostic methods are necessary. For beam profile measurement a system based on beam induced fluorescence (BIF) was designed and is under installation at the 100 keV polarized test setup at the Mainzer Mikrotron (MAMI) at the moment. For the diagnostic of other observables of the cooling beam, like the electron beam energy or the electron temperature, a Thomson scattering experiment is planned at the same setup. The planned experiments for the beam profile measurement are presented and the challenges of the Thomson scattering method are discussed.

MOPD54

Commissioning Results of the Photon-Electron Diagnostic Unit at sFLASH

laser, undulator, diagnostics, FEL

173

J. Bödewadt, E. Hass, J. Roßbach
Uni HH, Hamburg, Germany

Funding: Supported by the Federal Ministry of Education and Research of Germany under contract 05 ES7GU1
Recently a seeded free-electron laser operating in the extreme ultra-violet (XUV) spectral range was installed and commissioned at the free-electron laser FLASH. The seed beam is generated by higher harmonics of near infrared laser pulses. A dedicated transport system guides the radiation into the electron accelerator environment. Within the seed undulator section compact diagnostic units were installed to control the transverse overlap of the photon and the electron beam. These units contain a BPM, horizontal and vertical wire scanners and an OTR screen for the electron diagnostic. A Ce:YAG screen and a MCP readout for the wire scanner are used to measure the photon beam position. This paper presents the commissioning results and the performance of the diagnostic units.

MOPD77

Broadband Digital Feedback System for the VEPP-4M Electron-Positron Collider

feedback, kicker, betatron, positron

224

V.V. Oreshonok, V.V. Smaluk
BINP SB RAS, Novosibirsk, Russia
V.P. Cherepanov, V.V. Oreshonok, D.P. Sukhanov
NSU, Novosibirsk, Russia

To suppress the transverse instability, which is the main reason of beam current limitation at the VEPP-4M electron-positron collider, a digital bunch-by-bunch feedback system has been developed, installed and commissioned. The real-time data processing is performed by a special code running in an FPGA module. This provides high efficiency and flexibility of the system. During the system commissioning, a 3-times increase of the beam current injected into VEPP-4M was reached. The system design and data processing algorithms are described, the commissioning results are presented.

MOPD78

Synchronous Measurement of Stability of Electron Beam, X-ray Beam, Ground and Cavity Voltage

cavity, feedback, photon, controls

227

G. Rehm, M.G. Abbott, C. Bloomer, I. Uzun
Diamond, Oxfordshire, United Kingdom

We have developed hardware and software that allows continuous and synchronous recording of electron and X-Ray beam position as well as cavity voltage and ground vibrations at a rate of about 10kS/s for periods of many days. To this end, additional nodes have been added to our existing fast network that feeds the Fast Orbit Feedback System, namely tungsten vane type front end XBPMs, RF cavity pickups and accelerometers. The synchronous nature of these measurements shows the correlation between electron beam motion through an insertion device and observed X-ray beam motion in the frontend or orbit distortions caused by fluctuations of the RF cavity voltage. While the additional channels currently are only observed, the potential of including these in the fast orbit feedback will be discussed.

MOPD82

Installation for Measurements of Secondary Emission Yield and Electron Cloud Lifetime in Magnetic Field

cryogenics, cathode, vacuum, simulation

236

A.A. Krasnov, V.V. Anashin, V.K. Ovchar, V.V. Smaluk, D.P. Sukhanov
BINP SB RAS, Novosibirsk, Russia

An experimental setup for investigations of electron-surface interaction and electron cloud behavior is under commissioning at BINP. The proposed method provides direct measurements of secondary emission yield and electron clouds lifetime in the presence of strong magnetic field. In principle, the experiments can be performed at cryogenic temperatures. The experimental data will help to figure out the process of reflection of low energy electrons from a metal surface and can be useful for improvement of computer codes developed for simulation of electron clouds behavior in a cold beam pipe of particle accelerators. The structure and performance capabilities of the setup are described, first experimental results are presented.

MOPD84

Hollow Photocathode Prototype for e-Gun

laser, cathode, niobium, emittance

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]

MOPD88

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

ion, emittance, 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.

MOPD91

Pulse-By-Pulse X-ray Beam Monitor Equipped with Microstripline Structure

high-voltage, diagnostics, impedance, pick-up

260

H. Aoyagi, S. Takahashi
JASRI/SPring-8, Hyogo-ken, Japan
H. Kitamura
RIKEN/SPring-8, Hyogo, Japan

Pulse-by-pulse measurement of X-ray beam is import issue for the 3rd generation light sources in order not only to stabilize X-ray beam in an experimental hutch but also to diagnose electron beam in a storage ring. A new pulse-by-pulse X-ray beam monitor equipped with microstripline structure has been developed. The detector head has the microstripline structure. The impedance of the detector head is matched to 50 ohm. Thermodynamics of the detector head is also well considered against severe heat load. The advantage of this monitor is that output signal is short and unipolar pulse, so front-end electronics can be simplified. The feasibility tests have been demonstrated at the X-ray beamline of SPring-8 in the term of (1) pulse intensity monitor, (2) pulse-by-pulse X-ray beam position monitor, and (3) the pulse-timing monitor. Then, we have improved the structure of the detector head in order to sophisticate the function as the pulse timing monitor. As a result, we successfully removed the ringing parts of output signal, and demonstrated that this monitor can be used as the timing monitor. We also describe a new scheme for beam diagnostics using this monitor.

Poster MOPD91 [1.309 MB]

MOPD93

Investigation of Diagnostic Techniques on a Nonneutral Plasma

plasma, space-charge, ion, diagnostics

266

K. Schulte, M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: Work supported by HIC for FAIR, BMBF No. 06FY90891.
Space charge lenses use a confined electron cloud for the focusing of ion beams. The focusing strength is given by the electron density whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The plasma parameters, loss as well as production mechanisms have a strong impact on plasma beam interactions. A scaled up space charge lens was constructed to investigate the properties of a nonneutral plasmas in detail. New non-interceptive diagnostic has been developed to characterize the collective behaviour of the confined nonneutral plasma in terms of an optimized lens design and parameters. Experimental results will be presented in comparison with numerical simulations.

Poster MOPD93 [3.587 MB]

TUOA04

Instrumentation for Machine Protection at FERMI@Elettra

undulator, FEL, radiation, diagnostics

286

L. Fröhlich, A.I. Bogani, K. Casarin, G. Cautero, G. Gaio, D. Giuressi, A. Gubertini, R.H. Menk, E. Quai, G. Scalamera, A. Vascotto
ELETTRA, Basovizza, Italy
L. Catani, D. Di Giovenale
INFN-Roma II, Roma, Italy

FERMI@Elettra is a linac-driven free-electron laser currently under commissioning at Sincrotrone Trieste, Italy. In order to protect the facility's permanent undulator magnets from radiation-induced demagnetization,beam losses and radiation doses are monitored closely by an active machine protection system. The talk focuses on the design and performance of its main diagnostic subsystems: Beam loss position monitors based on the detection of Cherenkov light in quartz fibers with multi-pixel photon counters, conventional ionization chambers with a new frontend electronics package, and solid-state RadFET dosimeters providing an online measurement of the absorbed dose in the undulator magnets.

Slides TUOA04 [2.559 MB]

TUPD04

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

linac, diagnostics, emittance, site

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.

TUPD06

Beam Diagnostic Overview of the SPIRAL2 RNB Section

ion, controls, target, ion-source

314

C. Jamet, T.A. André, E. Guéroult, B. Jacquot, N. Renoux, A. Savalle, T. Signoret, F. Varenne, J.L. Vignet
GANIL, Caen, France
J.-M. Fontbonne
LPC, Caen, France

An extension to the existing GANIL facility in Caen, France is under construction. The new SPIRAL 2 construction will be realized in two phases, for the first phase the construction started in January 2011 and will consists of the accelerator buildings with two experimental facilities S3 and Neutrons for science (NFS). The second phase is the so called production building where radioactive ions are produced through the ISOL (Isotope Separation On Line) method. The produced radioactive ion beams (RIBs) will be extracted and accelerated up to 60keV from the ion sources, after beam purification the beam will be driven in the secondary beam lines either to a new experimental facility DESIR (Decay, excitation and storage of radioactive ions) constructed during the second phase of the new installation or the RIBs will be charge breed to form multi-charged ions that will be driven to the existing GANIL facility and post accelerated in the CIME cyclotron. This overview article gives a description of the secondary beam lines, the foreseen beam diagnostics which will allow tuning and controlling the radioactive ion beams in the secondary beam lines constructed in the SPIRAL2 Phase 2.

TUPD13

CLIC Drive Beam Position Monitor

damping, linac, luminosity, coupling

326

S.R. Smith, A. Cappelletti, D. Gudkov, L. Søby, I. Syratchev
CERN, Geneva, Switzerland
S.R. Smith
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE-AC02-76SF00515
CLIC, an electron-positron linear collider proposed to probe the TeV energy scale, is based on a two-beam scheme where RF power to accelerate a high energy luminosity beam is extracted from a high current drive beam. The drive beam is efficiently generated in a long train at modest frequency and current then compressed in length and multiplied in frequency via bunch interleaving. The drive beam decelerator requires >40000 quadrupoles, each holding a beam position monitor (BPM). Though resolution requirements are modest (2 microns) these BPMs face several challenges. They must be compact and inexpensive. They must operate below waveguide cutoff to insure locality of position signals, ruling out processing at the natural 12 GHz bunch spacing frequency. Wakefields must be kept low. We find compact conventional stripline BPM with signals processed below 40 MHz can meet requirements. Choices of mechanical design, operating frequency, bandwidth, calibration, and processing algorithm are presented. Calculations of wakes and trapped modes and damping are discussed.

TUPD14

Commissioning of the Cavity BPM for the FERMI@Elettra FEL Project

cavity, FEL, undulator, polarization

329

P. Craievich, T. Borden, A.O. Borga, R. De Monte, M. Ferianis, M. Predonzani
ELETTRA, Basovizza, Italy
M. Dal Forno, R. Vescovo
DIEIT, Trieste, Italy

The cavity Beam Position Monitor (BPM) is a fundamental beam diagnostic device that allows the measurements of the electron beam trajectory in a non-destructively way and with sub-micron resolution. Ten cavity BPM systems have been installed along the undulators chain in the FERMI@Elettra FEL1 project. In this paper we discuss the installation, commissioning and performance of these cavity BPM systems. We have carried out preliminary operations during a pre-beam period, such as the alignment and fine tuning of the RF cavities under vacuum. During the commissioning each BPM has been calibrated by mechanically moving the support on which the BPM is mounted. We have estimated the single shot resolution in presence of beam jitter by reading the beam position synchronously over many electron bunches from three or more BPMs. The algorithms have been subsequently improved, and the results are described.

Poster TUPD14 [0.460 MB]

TUPD15

Technology Selection for the Beam Position Tuning System in Hadrontherapy Facilities

photon, high-voltage, controls, proton

332

C. Belver-Aguilar, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós
IFIC, Valencia, Spain
E. Benveniste, M. Haguenauer, P. Poilleux
LLR, Palaiseau, France

Funding: CYCIT – IN2P3: AIC10-D-000518
The Beam Delivery System of some hadrontherapy facilities is characterized by having scanning magnets, which move the beam in order to irradiate all the tumor volume. To control the beam position, a Beam Position Monitor (BPM) is needed. The BPM described in this paper is a new type of BPM based on four scintillating fibers coupled to four photodiodes to detect the light produced by the fibers when intercepting the beam. We present here the study of the possible photodiodes able to read the light emitted by the scintillating fiber, and the tests performed in order to find the most suitable photodiode to measure the beam position from the variations in the beam current. The setup used for the tests comprises a Sr-90 source, which emits electrons, a scintillating fiber, converting these electrons into photons, and a photodiode, which detects the photons leaving the fiber. The photodiodes studied have been of two types: Avalanche Photodiode (APD) and Multi Pixel Photon Counter (MPPC). In this paper both photodiodes are compared and the results are presented.

TUPD17

Spatial Resolution Test of a BPMS for DESIREE Beam Line Diagnostics

ion, rfq, diagnostics, simulation

338

S. Das, A. Källberg
MSL, Stockholm, Sweden
J. Harasimowicz
The University of Liverpool, Liverpool, United Kingdom

Funding: Two of us (S.Das and J. Harasimowicz) acknowledge the financial support received from the European Commission within FP7 Marie Curie Initial Training Network DITANET
Spatial resolution of a beam profile monitoring system (BPMS) was tested. It will be a part of the DESIREE [1] diagnostics to monitor and cover the wide range of beam intensities and energies. The BPMS consists of an aluminum (Al) plate, a grid placed in front of Al, a microchannel plate (MCP), a fluorescent screen (F.S.), a PC, and a CCD camera [2]. A beam collimator containing a set of circular holes of different diameter and separation between them was built to check the spatial resolution of the system [3]. Two holes of diameter 1 mm, separated by 2 mm, in the collimator were used for this purpose. A proton beam was used for the measurements. It was observed that these holes create two beams of approximately same intensity of areas each of 1 mm in diameter with 2 mm separation between the beam centers on the screen, suggesting a resolution of 2 mm of the system. The resolution was tested for different beam energy (0.5-40 keV), and voltages applied on the Al and MCP plates. The experimental results will be compared with the simulations.
[1] www.msl.se;www.atom.physto.se/Cederquist/desiree_web_hc.html
[2] K. Kruglov et al, NIM A, 441, 595 (2002);Nucl. Phys. A, 701, 193c (2002)
[3] S. Das et al, Proceedíngs of DITANET workshop, Nov. 23-25, 2009

TUPD19

Initial Tests of New Electron and Photon Beam Position Monitor Electronics at the Advanced Photon Source

photon, brilliance, injection, controls

344

P. Leban
I-Tech, Solkan, Slovenia
G. Decker
ANL, Argonne, USA

Funding: Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by ANL, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357
Measurements were done at the Advanced Photon Source (APS) with Libera Brilliance+, connected to the small-aperture insertion device vacuum chamber pickup electrodes near the beamline 35-ID source point. A photoemission-based photon beam position monitor located 16.35 meters downstream of the center of the ID straight section was also monitored using Libera Photon electronics in horizontal/vertical configuration. Top-up injection transients were recorded simultaneously on both units, providing details about the electron and photon beam motions before, during, and after injection in the storage ring and beamline front end. FFT spectra from the APS-developed BSP-100 broadband BPM data acquisition electronics were compared with the Libera instruments. This article discusses the calibration procedure for electron and photon beam position monitors along with results of these measurements.

TUPD25

Design of Magnetic BPM and Error Corrections

simulation, shielding, vacuum, instrumentation

359

M. Shafiee, E. Ebrahimi, S.A.H. Feghhi
Shahid Beheshti University, Evin, Tehran, Iran

For beam position monitoring (BPM) purposes, two prominent approaches as a physical effect have been applied including electrostatic and magnetic. In electrostatic types, secondary emission from the electrodes can be a problem when strong beam loss occurs, in such a situation, a magnetic BPM may be chosen. For this purpose we made a magnetic BPM including a square shape of ferromagnetic core with winding on each side. In this case study we used it for detecting the position of wire which is including a pulsed current (as an electron bunch) produced by a PROTEK G305 pulse generator. A Tektronix 2235A oscilloscope was calibrated and used to measure the induced voltage of magnetic BPM. Measurement results have been compared with simulation using CST software and performed error corrections which are presented, with this regard we could measure the wire position with high resolution furthermore we deduced the wire position hasn’t linear relation with induced voltage and needs more physical and mathematical analyzing. This way propose us that we can use magnetic BPMs in this approach and calibrate them before installing on accelerators.

Poster TUPD25 [0.120 MB]

TUPD26

Cavity-based Beam Diagnostics at ELSA

cavity, extraction, resonance, target

362

T.R. Pusch, F. Frommberger, W. Hillert, B. Neff
ELSA, Bonn, Germany

Funding: Funded by DFG SFB/TR 16
Online monitoring of the intensity and position of an electron beam of a few hundred pA in the experiment beamlines at the ELSA facility is enabled by a system of resonant cavities. The position signal extracted from the resonators amounts to about 10^-19 W for 0.1 mm displacement at a beam current of 400 pA. It is separated from noise by phase-sensitive detection in a lock-in amplifier. The beam's position is obtained with a precision of one tenth of a millimeter, the signal strength being normalized by a beam current measurement with an uncertainty of a few pA. Via frequency mixing, the cavity signal of 1.5 GHz is converted down to a frequency below 100 kHz in order to be accepted by the amplifier, requiring a local oscillator stabilized by a feedback loop to 10^-6 precision. Details of the measurement system are presented.

TUPD28

Benchmarking the Performance of the Present Bunch Arrival Time Monitors at FLASH

pick-up, FEL, feedback, laser

365

M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, S. Ruzin, H. Schlarb, B. Schmidt, S. Schulz
DESY, Hamburg, Germany

Funding: This work is partly supported by IRUVX-PP, an EU co-funded project under FP7 (Grant Agreement 211285)
Presently, at FLASH four bunch arrival time monitors (BAM) are installed and in permanent operation. Moreover, they are incorporated in a longitudinal intra-bunch train feedback. In this paper, we present a review of the performance and the limitations of the current BAM design, based on the most recent machine studies. The detection principle of the monitor implements the electro-optical modulation of synchronised laser pulses. The RF and electro-optical front-ends are designed to be operated in a frequency band from DC up to 10 GHz. This allows for measuring the arrival time of each individual electron bunch at femtosecond resolution. The current design of the BAMs has been tested under the influence of disturbances on the arrival time measurement, such as variation of the bunch charge as well as deviation from the reference transverse bunch position. Those results will be incorporated in an upcoming design revision to upgrade the application and robustness of the BAMs.

TUPD30

Bunch Length Measurement using Coherent Cherenkov Radiation

laser, gun, linac, injection

368

K. Kan, T. Kondoh, T. Kozawa, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultra-short electron bunches on the order of 100 fs or less can be used in the study of ultrafast reactions and phenomena in time-resolved pump-probe experiments involving the application of techniques such as pulse radiolysis. Such electron bunches are also useful for electro-magnetic (EM) radiation production, where the frequency of EM radiation depends on the electron bunch length. In this presentation, Coherent Cherenkov Radiation (CCR), which is a method of THz radiation emitted from relativistic electron bunches, was studied for a diagnostic of electron bunch length. A picosecond electron bunch generated by a photocahode radio frequency (RF) gun was used. CCR can emit narrow-band THz wave with a dielectric-lined waveguide structure. The intensity and frequency of CCR were measured by a Michelson interferometer and a 4.2K liquid-He cooled bolometer.

TUPD31

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

RF-structure, FEL, emittance, 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.

TUPD32

THz Radiation Diagnostics for Monitoring the Bunch Compression at the SwissFEL Injector Test Facility

radiation, vacuum, simulation, FEL

374

C. Gerth, B. Schmidt, S. Wesch
DESY, Hamburg, Germany
R. Ischebeck, G.L. Orlandi, P. Peier, V. Schlott
PSI, Villigen, Switzerland

At the SwissFEL Injector Test Facility, installation of a magnetic chicane for longitudinal bunch compression is foreseen for the first half of 2011. Bunch compression will be accomplished by operating two S-band accelerating structures on-crest and two S-band structures at off-crest RF phases. An X-band structure for the linearization of the longitudinal phase space will be installed at a later stage. The detection of coherent synchrotron radiation or coherent diffraction radiation in the THz range can be used to monitor the bunch compression process and stabilize the RF phases by a beam-based feedback. In this paper, we study the source characteristics of the edge radiation emitted at the 4th dipole of the bunch compressor as well as the diffraction radiation generated by a metallic foil with a hole. Particle tracking simulations were used to model the bunch compression process for different operation modes. The performance of a bunch compression monitor consisting of focusing mirrors and band pass filters has been evaluated by simulating the THz radiation transport of the optical components.

TUPD33

Coherent Resonant Diffraction Radiation from Inclined Grating as a Tool for Bunch Length Diagnostics

radiation, diagnostics, vacuum, synchrotron

377

L.G. Sukhikh, G. Kube
DESY, Hamburg, Germany
A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia
V. Schlott
PSI, Villigen, Switzerland

There exists considerable interest in studying new types of non-invasive bunch length diagnostics for sub-picosecond bunches. In this context coherent Smith-Purcell radiation (CSPR) is a good candidate because the use of grating causes wavelength dispersive radiation emission, i.e. a CSPR based monitor does not require any additional spectrometer. In contrast to existing CSPR monitors a new scheme is proposed with two detectors placed at fixed positions, and a wavelength scan is performed by scanning the tilt angle between grating surface and beam axis. In this scheme the information of both detectors, positioned opposite to each other and perpendicular to the beam axis, can be combined by taking the intensity ratio of the signals from both detectors. The advantage of such diagnostics scheme is that one has not to rely on absolute values of the radiation yield, avoiding the need to know the sensitivity of each detector with high accuracy. In contrast to CSPR which is emitted from a grating oriented parallel to the beam, the effect is termed coherent resonant diffraction radiation when the grating is tilted. In the report we present simulation results and detailed experimental plan.

TUPD36

Progress and Status of the Laser-based Synchronization System at FLASH

laser, FEL, feedback, status

383

S. Schulz, M.K. Bock, M. Bousonville, M. Felber, P. Gessler, T. Lamb, F. Ludwig, S. Ruzin, H. Schlarb, B. Schmidt
DESY, Hamburg, Germany

Funding: This work is partly supported by IRUVX-PP an EU co-funded project under FP7 (Grant Agreement 211285).
The free-electron lasers FLASH and European XFEL demand a high timing accuracy between the electron bunches and external laser systems for both exploitation of the short VUV and X-ray pulses in time-resolved pump-probe experiments and seeded operation modes. The required precision can only be achieved with laser-based synchronization schemes. The prototype system installed at FLASH is continuously evolving and subject to improvements. In this paper, we give an overview on the present status, report on the latest developments and extensions, and discuss future challenges. Particularly, the recent move to a new type of master laser oscillator led to a significant enhancement of the robustness and reliability. Consequently, research can focus on the implementation of the electron bunch arrival time feedback, new technologies for timing distribution and integration of Ti:sapphire lasers into the optical synchronization system.

TUPD38

Design of a Single-Shot Prism Spectrometer in the Near- and Mid-Infrared Wavelength Range for Ultra-Short Bunch Length Diagnostics

simulation, radiation, diagnostics, optics

386

C. Behrens
DESY, Hamburg, Germany
A.S. Fisher, J.C. Frisch, A. Gilevich, H. Loos, J. Loos
SLAC, Menlo Park, California, USA

The successful operation of high-gain free-electron lasers (FEL) relies on the understanding, manipulation, and control of the parameters of the driving electron bunch. Present and future FEL facilities have the tendency to push the parameters for even shorter bunches with lengths below 10 fs and charges well below 100 pC. This is also the order of magnitude at laser-driven plasma-based electron accelerators. Devices to diagnose such ultra-short bunches even need longitudinal resolutions smaller than the bunch lengths, i.e. in the range of a few femtoseconds. This resolution is currently out of reach with time-domain diagnostics like RF-based deflectors, and approaches in the frequency-domain have to be considered to overcome this limitation. Our approach is to extract the information on the longitudinal bunch profile by means of infrared spectroscopy using a prism as dispersive element. In this paper, we present the design considerations on a broadband single-shot spectrometer in the near- and mid-infrared wavelength range (0.8 - 39.0 μm).

TUPD41

The Beam Halo Monitor for FLASH

diagnostics, laser, free-electron-laser, radiation

395

A. Ignatenko, N. Baboi, O. Hensler, M. Schmitz, K. Wittenburg
DESY, Hamburg, Germany
H.M. Henschel, W. Lange
DESY Zeuthen, Zeuthen, Germany
A. Ignatenko, W. Lohmann
BTU, Cottbus, Germany
S. Schuwalow
University of Hamburg, Hamburg, Germany

The Beam Halo Monitor (BHM) for FLASH based on pCVD diamond and monocrystalline sapphire sensors has been successfully commissioned and is in operation. It is a part of the beam dump diagnostics system that ensures safe beam dumping. The description of the BHM and experience gained during its operation are given in this paper.

TUPD43

XFEL Beam Loss Monitor System

beam-losses, undulator, controls, high-voltage

401

A. Kaukher, I. Krouptchenkov, B. Michalek, D. Nölle, H. Tiessen
DESY, Hamburg, Germany

European XFEL will have a sophisticated Machine Protection System, part of which - Beam Loss Monitors(BLM). The monitors will detect losses of electron beam, in order to protect the components of the XFEL from damage and excessive activation. For protection of undulators, BLMs with a scintillator bar will be used. BLMs at places with high radiation load will be equipped with fused silica rods. Beam dumps of the XFEL will be instrumented with glass-fiber BLMs. The BLMs were tested with an electron test-beam at DESY, as well as at FLASH. Due to large amount of light produced by scintillator and high gain of the used photomultiplier, no optical grease is needed in front of the photomultiplier' window, while typical cathode voltage is only 500-600 volt. The prototype with quartz glass was typically operated at higher cathode voltage. Good operation of all three types of BLMs prototypes was obtained. It is planned to use same monitors also for the FLASH2 project. Current status of the XFEL BLM system development will be presented.

TUPD48

Transition Radiation from a Cylindrical Target and Transverse Beam Size Diagnostics

target, radiation, optics, FEL

410

A. Potylitsyn
TPU, Tomsk, Russia
L.G. Sukhikh
DESY, Hamburg, Germany

For modern X-ray FELs like LCLS in SLAC, FLASH in DESY and constructed ones like European X-FEL the transverse beam profile diagnostics using well-known optical Transition Radiation (TR) is not a trivial task because of a short bunch length and instabilities. Due to these reasons a bunch emits any kind of radiation coherently that makes it impossible to determine transverse profile of such bunch. One may use radiation with wavelengths shorter than bunch length (e.g. EUV) to avoid the problem of radiation coherence. Because of a high quality of mirrors in that region needed to construct proper optical line we propose to use a cylindrical target instead of flat one. TR generated by the cylindrical target is wider than the one from the flat target. But in this case the radiation generated by particles with different impact-parameters relative to a cylinder axes depends on the point of interaction. Proper choice of cylinder parameters allows to obtain beam profile image without any additional optics. In this report we present the simulation results and show how the radiation from the cylindrical target may be used for the bunch transverse profile diagnostics with good space resolution.

TUPD50

Slice-Emittance Measurements at ELBE / SRF-Injector

emittance, 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.

TUPD51

Ionization Profile Monitors - IPM @ GSI

high-voltage, ion, synchrotron, space-charge

419

T. Giacomini, P. Forck
GSI, Darmstadt, Germany
J.G. De Villiers
iThemba LABS, Somerset West, South Africa
J. Dietrich
FZJ, Jülich, Germany
D.A. Liakin
ITEP, Moscow, Russia

The Ionization Profile Monitor in the SIS18 is frequently used for machine development. The permanent availability and the elaborated software user interface make it easy and comfortable to use. Additional to the beam profile data the device records the data of synchrotron dc current, dipole ramp and accelerating rf properties. The trend curves of these data are shown correlated to the beam profile evolution for a full synchrotron cycle from injection to extraction with 100 profiles/s. The reliable function is based on the optimized in-vacuum hardware design, like the stable high voltage connections, the electric field box with very uniform field distribution and the uv-light based calibration system. The permanent availability is based on the convenient software interface using the Qt library. A new IPM generation was recently commissioned in the experimental storage ring ESR at GSI and one in the COSY ring at FZ-Jülich. These monitors are enhancements of the SIS18 multiwire IPM but equipped with an especially developed large area 50x100 mm² optical particle detector of rectangular shape that is readout by a digital camera through a viewport.

TUPD53

A Low-Power Laser Wire with Fiber Optic Distribution

laser, diagnostics, scattering, pick-up

425

R.B. Wilcox, J.M. Byrd, M.S. Zolotorev
LBNL, Berkeley, California, USA
V.E. Scarpine
Fermilab, Batavia, USA

Funding: This work was supported by the US Department of Energy under contract DE-AC02-05CH11231.
Laser-based position diagnostics for hydrogen ion (H⁻) beams typically use high power optical pulses that must be transported via free space to the diagnostic point. It is difficult to maintain stable alignment through such systems, especially when multiple channels are required. We describe a method for distributing low power, amplitude modulated pulse trains via fiber optic, and detecting interaction with the H⁻ beam by synchronous detection of the stripped electrons. Trains of 10 ps, 10⁶⁴ nm pulses at 400 MHz repetition rate are modulated by a 1 MHz signal that is the reference for a lockin amplifier. The average beam power is below one Watt. Synchronous detection at RF frequencies allows for efficient noise rejection when using optical powers below the nonlinear (Raman scattering) threshold of an optical fiber. The laser is synchronized with the bunch repetition rate, so the diagnostic can be used for bunch length measurements as well. We present results of tests of the optical system with 10⁰ m, single-mode fiber and realistic detected signal levels, demonstrating detection of the modulation signal with high signal-to-noise ratio and low nonlinearity.

TUPD54

Comparison of Different Radiators used to Measure the Transverse Characteristics of Low Energy Electron Beams at PITZ

cathode, laser, radiation, FEL

428

S. Rimjaem, G. Asova, J.W. Bähr, H.-J. Grabosch, M. Gross, L. Hakobyan, I.I. Isaev, Ye. Ivanisenko, M.A. Khojoyan, G. Klemz, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, A. Shapovalov, F. Stephan, G. Vashchenko, S. Weidinger
DESY Zeuthen, Zeuthen, Germany
D. Richter
HZB, Berlin, Germany

The photoinjector test facility at DESY, Zeuthen site (PITZ), has been established for developing and optimizing electron sources for linac based Free Electron Lasers (FELs). Characterizations of electron beams with maximum energies of about 25 MeV are carried out at PITZ. In order to study properties of electron beams, several diagnostic systems are applied. One of the important investigations is the study of transverse beam profiles at different beam conditions. Three screen types -YAG powder coated, optical transition radiation (OTR), and CVD-diamond screen- are used as beam profile monitors and are installed in screen stations at different locations along the beam transport line. In addition, wire scanner systems are available in the beamline for the same purpose. In this contribution a comparison of measurement results from all three screen types and the wire scanner used to characterize long pulse trains will be presented and discussed.

Poster TUPD54 [0.193 MB]

TUPD55

Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN

vacuum, instrumentation, impedance, dipole

431

D. Egger
EPFL, Lausanne, Switzerland
A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca
CERN, Geneva, Switzerland

The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.

Poster TUPD55 [0.959 MB]

TUPD59

Suppression of Coherent Optical Transition Radiation in Transverse Beam Diagnostics by Utilising a Scintillation Screen with a Fast Gated CCD Camera

simulation, laser, FEL, linac

440

M. Yan
Uni HH, Hamburg, Germany
C. Behrens, C. Gerth, G. Kube, B. Schmidt, S. Wesch
DESY, Hamburg, Germany

Micro-bunching instabilities in high-brightness beams of linac-driven FELs can lead to coherence effects in the emission of optical transition radiation (OTR) used for standard transverse profile diagnostics, thus rendering it impossible to observe a direct image of the particle beam. By using a scintillation screen in combination with a fast gated CCD camera, coherence effects can be suppressed as OTR is created in an instantaneous process while scintillation light has a certain decay time. In addition, the emission of the scintillation light is a statistical process from many atoms which is completely insensitive to the longitudinal bunch structure and does not produce coherence effects. Gating the camera during the passage of the electron bunch should eliminate any influence of the coherent OTR (COTR). First experiments using this method have been performed successfully at FLASH as a proof-of-principle. In this paper, we study the applicability of scintillation screens for high-energy electron beams under operation conditions for which COTR is emitted. Experimental results together with simulations are presented and discussed in view of COTR suppression and spatial resolution.

TUPD63

Gas Electron Multipliers for the Antiproton Decelerator

vacuum, antiproton, cathode, high-voltage

449

S.C. Duarte Pinto, O.R. Jones, L. Ropelewski, J. Spanggaard, G. Tranquille
CERN, Geneva, Switzerland

The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light (~0.4% X₀), and measures horizontal and vertical profiles directly in one plane. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPCs) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another 3 detectors now installed in the ASACUSA beam line. This paper will provide a detailed description of the detector and discuss the initial results obtained.

TUPD68

Feasibility Study for a Single-Shot 3D Electron Bunch Charge Distribution Monitor with a Polarized Probe Laser at SPring-8 Photoinjector

laser, polarization, gun, monitoring

464

Y. Okayasu, H. Dewa, H. Hanaki, S. Matsubara, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan
T. Ishikawa
RIKEN Spring-8 Harima, Hyogo, Japan
A. Maekawa, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

It is essential for precise characterizations of light sources to monitor ever-changing charge distribution of electron bunch by single-shot measurement with high resolutions. Therefore, a single-shot and non-destructive 3D bunch charge distribution (BCD) monitor was developed to characterize longitudinal and transverse BCDs simultaneously. It is based on Electro-Optical (EO) multiple sampling with a manner of spectral decoding. For the transverse detection, eight EO-crystals surround the beam axis azimuthally, and a linear-chirped probe laser pulse with a hollow shape and spirally temporal shift, passes through the EO-crystals. A principle verification experiment has been successfully carried out with two EO-crystals in our facility. In addition, we are promoting a numerical calculation of the ultra-short and radial polarized laser transportation for our own system assuming eight EO-crystals usage in order to confirm observation feasibility. We report the principle and the first experimental results of the novel 3D-BCD monitor and introduce the feasibility demonstration with a calculation about a propagation of transverse polarization distributions along probe laser optics.

Poster TUPD68 [4.684 MB]

TUPD76

Vibration and Beam Motion Diagnostics in TLS

photon, status, diagnostics, monitoring

485

Y.K. Chen, J. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo
NSRRC, Hsinchu, Taiwan

High beam stability is essential in a modern synchrotron light source due to small emittance. Beam motion caused by various factors should be remedy by various approaches to achieve high beam stability. Vibration will deteriorate beam stability and need considered as a part of beam diagnostic. An integrated environment for beam orbit and vibration monitoring systems were set up for various studies. Implementation details and some beam observation will be presented in this report.

Poster TUPD76 [2.750 MB]

TUPD78

SOLEIL Beam Orbit Stability Improvements

photon, feedback, kicker, synchrotron

488

N. Hubert, L. Cassinari, J.-C. Denard, P. Lebasque, L.S. Nadolski, D. Pédeau
SOLEIL, Gif-sur-Yvette, France

SOLEIL beam orbit stability is being significantly improved. A first effort was set on long term stability for specific beamlines (new 160 m long Nanoscopium and Hard X-rays beamlines). BPM and XBPM steel supports will be replaced for reducing their sensitiveness to temperature drift. Thermal expansion of INVAR and fused Silica stands has been measured. INVAR has been selected for the new BPM supports. A second effort aimed at improving the orbit stability of beamlines based on bending magnets. We plan to use their first XBPM in the global orbit feedback loops (slow and fast). For that purpose new XBPM electronics called Libera photons will be used. Soleil, having contributed to the development, tested extensively the first series. A third effort focused on noise source location. An application developed in-house has identified localized orbit perturbation sources introducing spurious spectrum lines at 46, 50 and 54 Hz on the orbit. They originate from fans rotating close to ceramics chambers of kickers, FCT and shaker. Their suppression decreases the vertical integrated noise down to 300 nm in the DC-500Hz frequency range.

TUPD85

Photoinjector Based MeV Electron Microscopy

gun, emittance, 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.

TUPD88

A Micro-Channel Plate Based RFA Electron Cloud Monitor for the ISIS Proton Synchrotron

gun, proton, synchrotron, diagnostics

512

A. Pertica, S.J. Payne
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Electron clouds produced inside a particle accelerator vacuum chamber by the passage of the beam can compromise the operation of the accelerator. The build up of electron clouds can produce strong transverse and longitudinal beam instabilities which in turn can lead to high levels of beam loss often requiring the accelerator to be run below its design specification. To study the phenomena of electron clouds at the ISIS Proton Synchrotron, a Micro-Channel Plate (MCP) based electron cloud detector has been developed. The detector is based on the Retarding Field Analyser (RFA) design and consists of a retarding grid, which provides energy analysis of the electron signal, and a MCP assembly placed in front of the collector plate. The MCP assembly provides a current gain over the range 300 to 25K, thereby increasing the signal to noise ratio and dynamic range of the measurements. In this paper, we describe the lab based experiment used to test our detector using a low energy electron gun. Results from our MCP based detector installed in the ISIS accelerator ring are discussed and compared to a RFA detector, installed at the same location, which has no MCP fitted.

Poster TUPD88 [1.793 MB]

TUPD89

Polarimetry of 0.1 – 130 MeV Electron Beams at the S-DALINAC*

laser, polarization, linac, photon

515

C. Eckardt, P. Bangert, R. Barday, U. Bonnes, R. Eichhorn, J. Enders, C. Ingenhaag, Y. Poltoratska, M. Wagner
TU Darmstadt, Darmstadt, Germany

Funding: * Work supported by DFG through SFB 634 and by the state of Hesse through the Helmholtz International Center for FAIR in the framework of the LOEWE program.
A source of polarized electrons[1] has been installed at the superconducting 130 MeV Darmstadt electron linear accelerator S-DALINAC[2], augmenting the experimental program for nuclear structure studies and fundamental experiments. Polarized electrons from a strained-superlattice GaAs cathode are electrostatically accelerated to 100 keV. In the low-energy beam line the beam parameters are measured using diagnostic elements like wire scanners and RF-monitors, a Wien filter for spin manipulation and a 100 keV Mott polarimeter for polarization measurement. Following a superconducting accelerator section, electron beams with 5-10 MeV energy are used for bremsstrahlung experiments. Here, the absolute degree of polarization will be measured using a Mott polarimeter, while monitoring the beam polarization during the experiment with a Compton transmission polarimeter. Alternatively, the electron beam can be further accelerated in the recirculating superconducting main linac. For beam energies of 50-130 MeV a Moeller polarimeter as well as two Compton transmission polarimeter are foreseen. We report on the performance of the polarized source and the polarimeter design and installation.
[1] C. Eckardt et al., IPAC 10, Kyoto, _{_}THPEC019_{_}, p 4083.
[2] A. Richter, Proc. EPAC 96, Sitges, _{_}WEX02A_{_}, p.110.

TUPD93

Diagnostics of RF Breakdowns in High-Gradient Accelerating Structures

collider, plasma, vacuum, linear-collider

527

A. Palaia
Uppsala University, Uppsala, Sweden
V.A. Dolgashev, J.R. Lewandowski, S.P. Weathersby
SLAC, Menlo Park, California, USA

Within the framework of the research on high-gradient accelerating structures for future linear colliders, diagnostics of radio-frequency (RF) breakdowns is of great importance to support the understanding of the vacuum breakdown process. Measurements of RF and electron and ion currents emitted during and after a breakdown can be used to calculate the properties of any objects responsible for such power reflection and charge emission. Possible breakdown models, breakdown localization and a time-scale of the process are here discussed and compared to dedicated measurements. First results are presented.

Poster TUPD93 [7.029 MB]

TUPD97

Diagnostic System of TAC IR FEL Facility

FEL, emittance, 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, emittance, diagnostics

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]

WEOA02

Experimental Investigations of Backward Transition Radiation from Flat Target in Extreme Ultraviolet Region

radiation, target, diagnostics, FEL

544

L.G. Sukhikh, G. Kube
DESY, Hamburg, Germany
D. Krambrich, W. Lauth
IKP, Mainz, Germany
Yu.A. Popov, A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia

Forward transition radiation in X-ray range and backward transition radiation (BTR) in optical spectral region are investigated in details due to their use for purposes of particle and beam diagnostics. In order to improve diagnostics tools we proposed to use BTR in extreme ultraviolet (EUV) region [*,**], where theoretical models are existing only. We performed experimental investigations of BTR characteristics in EUV spectral region generated by a molybdenum target at 855 MeV electron beam of the MAMI-B (Mainz, Germany). Angular patterns and intensities of BTR both in optical and EUV regions for different observation angles were investigated. The measured intensity of optical BTR agrees with a theory with reasonable accuracy but one in EUV region is more intense than theoretically predicted. Our experimental estimation of the experimental BTR yield in EUV region is (2.4/3.6)•10⁻⁴ photons/electron and this is more than 4 / 6 times higher than the theoretical value.
* L.G. Sukhikh, S.Yu.Gogolev and A.P.Potylitsyn, Nucl. Instrum. Methods Phys. Res., Sect. A 623, 567 (2010)
** L.G. Sukhikh, S.Yu.Gogolev and A.P.Potylitsyn, J. Phys.: Conf. Ser. 236, 012011 (2010).

Slides WEOA02 [6.967 MB]

WEOA03

Detailed Experimental Characterization of an Ionization Profile Monitor

extraction, ion, space-charge, target

547

J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou
CEA, Gif-sur-Yvette, France
F. Becker, P. Forck, B. Walasek-Höhne
GSI, Darmstadt, Germany
J. Marroncle
CEA/DSM/IRFU, France

Funding: Marie Curie Fellowship by the EU
In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.

Slides WEOA03 [1.964 MB]

WEOB01

Scintillating Screen Applications in Beam Diagnostics

ion, diagnostics, photon, scattering

553

B. Walasek-Höhne
GSI, Darmstadt, Germany
G. Kube
DESY, Hamburg, Germany

Scintillation screens are widely used for transverse beam profile diagnostics at particle accelerators. The monitor principle relies on the fact that a charged particle crossing the screen material will deposit a part of its energy which is converted to visible light. The resulting light spot is a direct image of the two-dimensional beam distribution and can be measured with standard optical techniques. Scintillating screen monitors were mainly deployed in hadron and low energy electron machines where the intensity of optical transition radiation (OTR) is rather low. The experience from modern linac based light sources showed that OTR diagnostics might fail even for high energetic electron beams, thus making the use of scintillators again very attractive. This contribution summarizes results and trends from "Scintillating Screen Applications in Beam Diagnostics" workshop recently held in Darmstadt. In the first part an introduction to the scintillation mechanism will be given, including demands and limitations as e.g. the dynamic range and saturation. Thereafter a brief overview on actual screen monitor applications at electron and hadron accelerators will be presented.

Slides WEOB01 [14.721 MB]

WEOB02

Experimental Comparison of Performance of Various Fluorescent Screens Applied for Relativistic Electron/Positron Beam Imaging

positron, diagnostics, booster, laser

558

O.I. Meshkov, V.A. Kiselev, D.P. Sukhanov, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov, V.V. Smaluk
BINP, Novosibirsk, Russia
E.N. Galashov
Nikolayev Institute of Inorganic Chemistry, Novosibirsk, Russia

Fluorescent screens are widely used for single-pass measurements of transverse beam profile at most of accelerator facilities. Great number of materials is now used for manufacture of fluorescent screens. The linearity, sensitivity and spatial resolution of the diagnostics depend on the choice of screen substance. We made an attempt to compare a linearity and relative light yield for few types of the fluorescent materials applied for screen manufacturing. A CCD-camera and photomultiplier tube record the light flux and 2D profile of the electron/positron beam image on the screen. Experiments were carried out with the electron/positron beam energy of 350 MeV and the beam charge of 0.1 – 100 pC.

Slides WEOB02 [3.454 MB]

WEOD01

Beam Induced Fluorescence Monitors

ion, photon, diagnostics, proton

575

F. Becker
GSI, Darmstadt, Germany

Non-intercepting diagnostic devices in hadron accelerators offer continuous online monitoring capability. They also avoid the problem of potential thermal damage in high-current applications. Taking advantage of the residual gas as active material, the Beam Induced Fluorescence (BIF) monitor exploits gas fluorescence in the visible range for transversal profile measurements. Depending on beam parameters and vacuum-constraints, BIF monitors can be operated at base-pressure or in dedicated local pressure bumps up to the mbar range. Nowadays, BIF monitors are investigated in many accelerator laboratories for hadron energies from about 100 keV up to several 100 GeV. This talk gives an introduction to the measurement principle and typical operating conditions. It summarises recent investigations, e.g. on different working gases, and it compares various technical realisations.

Slides WEOD01 [12.701 MB]