IBIC2013 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MOAL4	First Results from the Bunch Arrival-Time Monitor at the SwissFEL Test Injector	pick-up, laser, gun, feedback	8
	V.R. Arsov, M.M. Dehler, S. Hunziker, M.G. Kaiser, V. Schlott PSI, Villigen PSI, Switzerland
	Non-destructive electron bunch arrival-time monitors (BAMs) with resolution <10 fs, sensitivity down to 10 pC and high intrinsic bandwidth for double bunch detection are required for reliable operation of SwissFEL. To achieve this ultimate goal, such a monitor based on a Mach-Zehnder electro-optical intensity modulator has been under development at the SwissFEL Test Injector. The high timing precision is derived by a stable pulsed optical reference system. The first BAM is located before the bunch compressor where the bunch energy is 230 MeV and the pulse length is approximately 3 ps. At this position, the bunch arrival time is sensitive to the laser- and gun timing. In this paper, we report on the commissioning of the RF- and optical front ends, the first arrival-time jitter and drift measurements with the entire system, as well as correlation of the arrival-time with different machine and environmental parameters. We achieve a resolution of 20 fs down to 60 pC.
	Slides MOAL4 [1.228 MB]

MOBL1	Instrumentation and Results from the SwissFEL Injector Test Facility	radiation, diagnostics, transverse, laser	12
	R. Ischebeck, V.R. Arsov, S. Bettoni, B. Beutner, M.M. Dehler, A. Falone, F. Frei, I. Gorgisyan, Ye. Ivanisenko, P.N. Juranic, B. Keil, F. Löhl, G.L. Orlandi, M. Pedrozzi, P. Pollet, E. Prat, T. Schietinger, V. Schlott, B. Smit PSI, Villigen PSI, Switzerland P. Peier DESY, Hamburg, Germany
	The SwissFEL Injector Test Facility (SITF) has been equipped with numerous prototype diagnostics (BPMs, screen monitors, wire scanners, optical synchrotron radiation monitor, compression (THz) monitor, bunch arrival time monitor, EO spectral decoding monitor, charge and loss monitor) specifically designed for the low charge SwissFEL operation modes. The design of the diagnostics systems and recent measurement results will be presented.
	Slides MOBL1 [35.165 MB]

MOBL3	Electron Bunch Diagnostic at the Upgraded ELBE Accelerator: Status and Challenges	ELBE, laser, diagnostics, pick-up	23
	M. Kuntzsch, S. Findeisen, M. Gensch, B.W. Green, J. Hauser, S. Kovalev, U. Lehnert, P. Michel, F. Röser, Ch. Schneider, R. Schurig HZDR, Dresden, Germany A. Al-Shemmary, M. Bousonville, M.K. Czwalinna, T. Golz, H. Schlarb, B. Schmidt, S. Schulz, N. Stojanovic, S. Vilcins DESY, Hamburg, Germany E. Hass Uni HH, Hamburg, Germany
	Within the ELBE upgrade towards a Center for High Power Radiation Sources (HSQ), a mono energetic positron, a liquid lead photo neutron source and two new THz sources have been installed at the superconducting electron linac at ELBE. A variety of established as well as newly developed electron beam diagnostics were installed and tested. In this paper we want to present first results achieved with the currently existing prototype beam arrival time and bunch compression monitors (BAM, BCM) as well as one versatile EOS set-up. Based on these future developements and upgrades are discussed.
	Slides MOBL3 [3.578 MB]

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

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

MOPC06	Beam Diagnostics System for a Photo-Neutron Source Driven by 15MeV Electron Linac	beam-position, linac, diagnostics, BPM	57
	Y.B. Yan, J. Chen, Z.C. Chen, Y.B. Leng, L.Y. Yu, R.X. Yuan, W.M. Zhou SINAP, Shanghai, People's Republic of China
	A photo-neutron source driven by 15MeV electron LINAC is under construction at Shanghai Institute of Applied Physics (SINAP). Several kinds of beam monitors (BPM, Profile and ICT) have been installed. The stripline beam position monitor with eight electrodes was designed, also for energy spread measurement. Due to the multi-bunch operation mode, a custom RF front end was adopted, which down-converts the signal from 2856MHz to 500MHz and then brings it to Libera Single Pass E. The beam position monitor was based on the integrated step-servo motor and GigE Vision camera. For the beam charge measurement we used the ICT from Bergoz and scope from Agilent. The detail of the whole beam diagnostics system development will be reported in this paper.

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

MOPC22	A New High-Dynamic Range BPM for ELBE with Integrated Differential Current Monitor (DCM)	BPM, ELBE, single-bunch, FEL	104
	A. Büchner, B. Lange HZDR, Dresden, Germany
	ELBE is a LINAC electron accelerator for small energies (12 to 50 MeV). It serves as a beam source for many quite different experiments. The recent ELBE upgrade allows electron beams with bunches in the range of single electrons to 1 nC. The maximum beam current is 1.6 mA CW and the repetition rates covering the range from one shot single bunch pulses to 26 MHz CW. The existing BPMs and especially the DCMs which are used for the Machine Protection System cannot handle this wide parameter range. To improve this situation the development of new BPMs / DCMs was necessary. The DCMs measure the difference of the beam current between two stripline sensors and produce an interlock for differences greater 10 microamps. The new BPM electronics system has been designed including the DCM functionality because both BPMs and DCMs use the same stripline sensor signals at 1.3 GHz.

MOPC25	About BPMS to be Used for PAL-XFEL	BPM, pick-up, XFEL, beam-position	112
	H. J. Choi, H.-S. Kang, C. Kim, S.H. Kim, S.J. Lee, S.J. Park, H. Yang PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory (PAL) has been building the X-Ray Free Electron Laser (XFEL), a fourth-generation accelerator, and the construction will be complete in 2015. To successfully construct the XFEL, PAL built an injection test facility (ITF) in 2012, and the facility is in operation. The ITF examines the efficiency of various diagnostic units through extended tests. A BPM is a diagnostic unit that measures the position of an electron bunch. There are various kinds of BPM, and they have different merits and demerits. A user can select any kind of BPM that is appropriate for their purpose, and install it after going through various design and production processes. In order to measure the position of an electron bunch, a cavity BPM is installed at an undulator of PAL-XFEL and a stripline BPM is installed at an accelerator. The efficiency of the stripline BPM was tested at the ITF. The X-band cavity BPM was produced and is being tested at the ITF. This paper aims to introduce the specification and properties of the cavity BPM and stripline BPM to be installed at PAL-XFEL, and explain the physical concept and the way of measuring necessary for designing a stripline pickup.

MOPC33	Status of the Fiber Link Stabilization Units at FLASH	laser, free-electron-laser, FEL, polarization	139
	F. Zummack, M.K. Czwalinna, M. Felber, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo DESY, Hamburg, Germany S. Jabłoński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	State-of-the-art X-ray photon science with modern free-electron lasers (FEL) like FLASH and the upcoming European X-ray Free-Electron Laser Facility (XFEL) requires timing with femtosecond accuracy. For this purpose a sophisticated pulsed optical synchronization system distributes precise timing via length-stabilized fiber links throughout the entire FEL. Stations to be synchronized comprise bunch arrival time monitors, RF stations and optical cross-correlators for external lasers. The different requirements of all those stations have to be met by one optical link-stabilization-unit (LSU) design, compensating drifts and jitter in the distribution system down to a fs-level. Five years of LSU operation at FLASH have led to numerous enhancements resulting in an elaborate system. This paper presents these enhancements, their impact on synchronization performance and the latest state of the LSUs.

MOPC36	Test of a Non-Invasive Bunch Shape Monitor at GSI High Current LINAC	linac, longitudinal, GSI, MCP	151
	P. Forck, C. Dorn, O.K. Kester, P. Kowina, B. Zwicker GSI, Darmstadt, Germany O.K. Kester IAP, Frankfurt am Main, Germany
	Funding: The work is funded by European Union FP7 within CRISP. At the heavy ion LINAC at GSI, a novel scheme of non-invasive Bunch Shape Monitor has been tested with several ion beams at 11.4 MeV/u. The monitor’s principle is based on the analysis of secondary electrons as liberated from the residual gas by the beam impact. These electrons are accelerated by an electrostatic field, transported through a sophisticated electrostatic energy analyzer and an RF-deflector, acting as a time-to-space converter. Finally a MCP amplifies electrons and with a CCD camera the electron distribution is detected. For the applied beam settings this Bunch Shape Monitor is able to obtain longitudinal profiles down to a width of 400 ps with a resolution of 50 ps, corresponding to 2 degree of the 108 MHz accelerating frequency. Systematic parameter studies for the device were performed to demonstrate the applicability and to determine its resolution. The achievements and ongoing improvements for the monitor are discussed.
	Poster MOPC36 [2.665 MB]

MOPC37	Longitudinal Bunch Profile Reconstruction Using Broadband Coherent Radiation at FLASH	radiation, longitudinal, transverse, laser	154
	E. Hass Uni HH, Hamburg, Germany C. Behrens, C. Gerth, B. Schmidt, M. Yan DESY, Hamburg, Germany S. Wesch HZB, Berlin, Germany
	The required high peak current in free-electron lasers is realized by longitudinal compression of the electron bunches to sub-picosecond length. Measurement of the absolute spectral intensity of coherent radiation emitted by an electron bunch allows monitoring and reconstruction of the longitudinal bunch profile. To measure coherent radiation in the teraherz and infrared range a in-vacuum coherent radiation intensity spectrometer was developed for the free-electron laser in Hamburg(FLASH). The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels: it can be operated either in short (5-44 um) or in long wavelength mode (45-430 um). Fast parallel readout permits the monitoring of coherent radiation from single electron bunches. Large wavelength coverage and superb absolute calibration of the device allows reconstruction of the longitudinal bunch profile using Kramers-Kronig based phase retrieval technique. The device is used as a bunch length monitor and tuning tool during routine operation at FLASH. Comparative measurements with radio-frequency transverse deflecting structure show excellent agreement of both methods.

MOPC47	Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3	beam-losses, quadrupole, CLIC, simulation	189
	E. Nebot Del Busto, S. Mallows, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom E. Branger Linköping University, Linköping, Sweden S. Döbert, E.B. Holzer, R.L. Lillestøl, S. Mallows, E. Nebot Del Busto CERN, Geneva, Switzerland R.L. Lillestøl University of Oslo, Oslo, Norway C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the beam, the shielding provided by the different elements of the line, the detector sensitivity and possible saturation effects of both the radiation detectors and electronics.

MOPF06	Beam Profile Monitors at REGAE	diagnostics, photon, optics, SNR	212
	H. Delsim-Hashemi, K. Flöttmann DESY, Hamburg, Germany S. Bayesteh Uni HH, Hamburg, Germany
	A new linac is commissioned at DESY mainly as the electron source for femtosecond electron diffraction facility REGAE (Relativistic Electron Gun for Atomic Exploration). REGAE enables studies on structural dynamics of atomic transition states occurring in the sub-hundred femtosecond time-scale. REGAE comprises a photo-cathode gun followed by normal conducting 1.5 cell rf-cavity to provide sub pC electron-bunches of 2-5 MeV with a coherence length of 30nm. In order to produce and maintain such electron bunches, sophisticated single-shot diagnostics are desired e.g. emittance, energy, energy-spread and bunch-length measurement. REGAE rep-rate can be up to 50 Hz. This relatively high rep-rate makes it more challenging to deal with low intensity detection especially in single-shot mode. In this contribution the conceptual ideas, realization and results of transversal diagnostics will be presented.

MOPF09	A Gas-Jet Profile Monitor for the CLIC Drive Beam	ion, CLIC, space-charge, focusing	224
	A. Jeff, E.B. Holzer, T. Lefèvre CERN, Geneva, Switzerland A. Jeff, V. Tzoganis, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.

MOPF10	Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics	undulator, radiation, CLIC, transverse	228
	A. Jeff, T. Lefèvre CERN, Geneva, Switzerland A. Jeff, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Jeff, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMAX simulations using the CLIC Drive Beam parameters are shown.

MOPF16	Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System	laser, transverse, OTR, photon	243
	L.J. Nevay JAI, Egham, Surrey, United Kingdom A.S. Aryshev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan S.T. Boogert, P. Karataev, K.O. Kruchinin Royal Holloway, University of London, Surrey, United Kingdom L. Corner, R. Walczak Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	The laserwire system at the Accelerator Test Facility 2 (ATF2) is a transverse beam profile measurement system capable of measuring a micrometre-size electron beam. We present recent results demonstrating a measured vertical size of 1.16 ± 0.06 μm and a horizontal size of 110.1 ± 3.8 μm. Due to the high aspect ratio of the electron beam, the natural divergence of the tightly focussed laser beam across the electron beam width requires the use of the full overlap integral to deconvolve the scans. For this to be done accurately, the propagation of the 150 mJ, 167 ps long laser pulses was precisely measured at a scaled virtual interaction point.

MOPF20	Bunch Purity Measurement for BEPCII	synchrotron, photon, synchrotron-radiation, radiation	252
	H. Jun, J.S. Cao, J.H. Junhui IHEP, Beijing, People's Republic of China
	The bunch purity is very important for time-resolved experiments. It is determined by the quality of the injection system and Touschek effect. The Beijing Electron-Positron Collider (BEPC) II was constructed for both high energy physics (HEP) and synchrotron radiation (SR) researches. It can be operated in the colliding mode and synchrotron radiation mode. It is planned to measure the beam quality in a short time of several minutes by using a timecorrelated single photon counting method. The method has a time resolution of 450 ps and a dynamic range of five orders of magnitude. In this paper, we describe our experimental set up and give a series of test results for colliding mode. We plan to set up a system which can kick out the unwanted bunches in the next stage.

MOPF30	Novel Diagnostics for Breakdown Studies	CLIC, simulation, klystron, diagnostics	287
	M. Jacewicz, Ch. Borgmann, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden J.W. Kovermann CERN, Geneva, Switzerland
	The phenomenon that currently prevents achieving high accelerating gradients in high energy accelerators such as the CLIC linear collider is electrical breakdown at very high electrical field. The ongoing experimental work is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. The CLIC collaboration has commissioned a dedicated 12 GHz test-stand to validate the feasibility of accelerating structures and observe the characteristics of the RF discharges and their eroding effects on the structure. A versatile system for detection of the dark and breakdown currents and light emission is being developed for the test-stand. It consists of a collimation system with an external magnetic spectrometer for measurement of the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. These measurements can be correlated with e.g. the location of the breakdown inside the structure using information from the incident, reflected and transmitted RF powers giving a complete picture of the vacuum breakdown phenomenon.

MOPF31	Design and Performance of the Biased Drift Tube System in the BNL Electron Lens	RHIC, beam-losses, vacuum, ion	291
	T.A. Miller, W. Fischer, D.M. Gassner, X. Gu, A.I. Pikin, S. Polizzo, P. Thieberger BNL, Upton, Long Island, New York, USA J. Barth Barth Electronics, Boulder City, USA
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. The installation of the Electron Lenses in RHIC will be completed this year. Its design includes a series of drift tubes through which the electron beam copropagates, with the RHIC proton beams. These drift tubes are used to create an electric field gradient to sweep out ions that become trapped within the central magnetic field where the electron beam interacts with the proton beams. These isolated drift tubes are biased by high voltage power supplies. Without a path for the proton beam image currents, high voltages will develop on the drift tubes that can be detrimental to the electron beam and increase the RHIC machine impedance. This paper presents the design of the drift tubes, axial electric field gradient, and the custom high voltage RF bias tees that were designed to provide separate paths for the high frequency image currents and the DC high voltage bias over the same cables. The design and simulation of the bias tee is discussed, as well as RF signals from the proton beam current imaged on the drift tubes, as measured through the bias tees during the commissioning of the blue RHIC beam electron lens this past spring.
	Poster MOPF31 [31.237 MB]

TUAL2	Commissioning the New LCLS X-band Transverse Deflecting Cavity with Femtosecond Resolution	FEL, LCLS, undulator, linac	308
	P. Krejcik, F.-J. Decker, Y. Ding, J.C. Frisch, Z. Huang, J.R. Lewandowski, H. Loos, J.L. Turner, J.W. Wang, M.-H. Wang, J.J. Welch SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany
	Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515 The new X-band transverse deflecting cavity began operation in May 2013 and is installed downstream of the LCLS undulator. It is operated at the full 120 Hz beam rate without interfering with the normal FEL operation for the photon users. The deflected beam is observed on the electron beam dump profile monitor, which acts as an energy spectrometer in the vertical plane. We observe, on a pulse by pulse basis, the time resolved energy profile of the spent electron beam from the undulator. The structure is powered from a 50 MW X-band klystron, giving a 48 MV kick to the beam which yields a 1 fs rms time resolution on the screen. We have measured the longitudinal profile of the electron bunches both with the FEL operating and with the lasing suppressed, allowing reconstruction of both the longitudinal profile of the incoming electron beam and the time-resolved profile of the X-ray pulse generated in the FEL. We are immediately able to see whether the bunch is chirped and which parts of the bunch are lasing, giving us new insight into tuning the machine for peak performance. The performance of the system will be presented along with examples of measurements taken during LCLS operation.
	Slides TUAL2 [9.210 MB]

TUAL3	Absolute Bunch Length Measurements at Fermi@ELETTRA FEL	radiation, ELETTRA, background, instrumentation	312
	R. Appio MAX-lab, Lund, Sweden P. Craievich, G. Penco, M. Veronese Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy P. Craievich PSI, Villigen PSI, Switzerland
	Electron bunch length measurements are of crucial importance for many types of accelerators, including storage rings, energy recovery linacs, free electron lasers. Many devices and instrumentation have been developed to measure and control the electron bunch length. A very powerful class of diagnostic tools is based on the coherent radiation power emitted by the electron bunch, that allows a non-destructive shot by shot measurement, well suitable for bunch length control feedback implementation. However they usually provide measurements of the bunch length relative variation, and external instrumentation like a transverse RF deflecting cavity is usually needed to calibrate them and to obtain absolute bunch length estimations. In this paper we present a novel experimental methodology to self-calibrate a device based on diffraction radiation from a ceramic gap. We indeed demonstrate the possibility to use coherent radiation based diagnostic to provide absolute measurements of the electron bunch length. We present the theoretical basis of the proposed approach and validate it through a detailed campaign of measurements that have been carried on in the FERMI@Elettra FEL linac.
	Slides TUAL3 [1.126 MB]

TUCL1	Overview of Imaging Sensors and Systems Used in Beam Instrumentation	radiation, optics, controls, instrumentation	331
	E. Bravin CERN, Geneva, Switzerland
	The presentation will give an overview of applicable image sensors and sensor systems for an application in the beam instrumentation. The overview will cover fast imaging cameras as well as sensors and cameras to be used in radiation fields. The critical parameters will be discussed and measurements presented if available. Frame grabbers and digital cameras will also be included in the presentation.
	Slides TUCL1 [8.924 MB]

TUCL3	Gas Electron Multipliers Versus Multi Wire Proportional Chambers	CERN, antiproton, ion, transverse	342
	S.C. Duarte Pinto Delft University of Technology, Opto-electronic Section, Delft, The Netherlands J. Spanggaard CERN, Geneva, Switzerland
	Gas Electron Multiplication technology is finding more and more applications in beam instrumentation and at CERN these detectors have recently been adapted for use in transverse profile measurements at several of our facilities. In the experimental areas of CERN’s Antiproton Decelerator, low energy Gas Electron Multipliers successfully replaced all Multi-Wire Proportional Chambers in 2012 and another detector type has now been developed for high energy applications in the experimental areas of the SPS, totalling a potential of more than a hundred profile detectors to be replaced by GEM detectors of different types. This paper aims to describe the historical evolution of GEM technology by covering the many different applications but with specific focus on its potential to replace Multi-Wire Proportional Chambers for standard transverse profile measurement.
	Slides TUCL3 [3.275 MB]

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

TUPC06	Status of Beam Diagnostic Systems for TRIUMF Electron Linac	BPM, diagnostics, target, linac	361
	V.A. Verzilov, P.S. Birney, D.P. Cameron, P. Dirksen, J.V. Holek, S.Y. Kajioka, S. Kellogg, M. Lenckowski, M. Minato, W.R. Rawnsley TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada J.M. Abernathy, D. Karlen, D.W. Storey Victoria University, Victoria, B.C., Canada
	TRIUMF laboratory is currently in a phase of the construction of a superconducting 50 MeV 10 mA cw electron LINAC to drive photo-fission based rare radioactive isotope beam (RIB) production. The project imposes certain technical challenges on various accelerator systems including beam diagnostics. In the first place these are a high beam power and strongly varying operating modes ranging from microsecond beam pulses to the cw regime. Diagnostics development interleaves with the construction of the diagnostics instrumentation required for the test facility which delivered the first beam in Fall of 2011. The paper reports the present status of various diagnostics systems along with measurement results obtained at the test facility.

TUPC10	Operation of Diamond Light Source XBPMs with Zero Bias	DIAMOND, photon, synchrotron, beam-position	376
	C. Bloomer, G. Rehm Diamond, Oxfordshire, United Kingdom
	Tungsten blade X-ray Beam Position Monitors (XBPMs) have been used at Diamond Light Source since 2007, however a long-standing problem with these devices has been the growth of leakage current through the ceramic insulation within the XBPMs over time, often becoming greater than 10% of the signal current after a few years of operation. The growth of these leakage currents has been found to be exacerbated by the application of a negative bias (-70V) to the tungsten blades, a bias suggested for optimum position sensitivity. This bias is applied in order to accelerate free electrons away from the surface of the blades and to prevent cross-talk, however, we have found that the operation of the XBPMs without bias has negligible impact on our measurements. Removal of the bias has been found to prevent the growth of leakage currents over time, and can also significantly reduce the cost of our signal acquisition by removing the need for a low-current amplifier with a bias supply.
	Poster TUPC10 [0.455 MB]

TUPC18	Development of a Highly Efficient Energy Kicker for Longitudinal Bunch-by-Bunch Feedback	kicker, longitudinal, synchrotron, storage-ring	407
	M. Masaki, T. Fujita, K. Kobayashi, T. Nakamura, H. Ohkuma, M. Oishi, S. Sasaki, M. Shoji JASRI/SPring-8, Hyogo-ken, Japan
	A highly efficient energy kicker has been developed for longitudinal bunch-by-bunch feedback to suppress synchrotron oscillation of a high-current single electron bunch, and to cure possible longitudinal multi-bunch instability if lower beam energy is to be adopted for emittance reduction and electric power saving in a future upgrade plan of SPring-8. Through the performance test using a prototype kicker, a new water-cooled copper kicker was designed and fabricated, and it has been installed in the storage ring. The new kicker consists of three cells with each cavity length of 96 mm, its resonant frequency of 1.65 GHz, which is 3.25 times of RF frequency of the storage ring, and low Q-factor of 4.2. In beam kick test, the synchrotron oscillation amplitude of 0.64 ps was excited by kick voltage with continuous amplitude modulation at synchrotron frequency when the RF input power was 132 W/3cells. The kick voltage evaluated from the experimental result is 920 V/3cells. Shunt impedance of each kicker cell is estimated as 1.1 kΩ. As we intended, the shunt impedance per length is about three times higher than those of widely used waveguide overloaded cavity type kickers.
	Poster TUPC18 [9.117 MB]

TUPC36	First Realization and Performance Study of a Single-Shot Longitudinal Bunch Profile Monitor Utilizing a Transverse Deflecting Structure	longitudinal, FEL, feedback, kicker	456
	M. Yan, C. Behrens, C. Gerth, R. Kammering, A. Langner, F. Obier, V. Rybnikov DESY, Hamburg, Germany J. Wychowaniak TUL-DMCS, Łódź, Poland
	For the control and optimization of electron beam parameters at modern free-electron lasers (FEL), transverse deflecting structures (TDS) in combination with imaging screens have been widely used as robust longitudinal diagnostics with single-shot capability, high resolution and large dynamic range. At the free-electron laser in Hamburg (FLASH), a longitudinal bunch profile monitor utilizing a TDS has been realized. In combined use with a fast kicker magnet and an off-axis imaging screen, selection and measurement of a single bunch out of the bunch train with bunch spacing down to 1us can be achieved without affecting the remaining bunches which continue to generate FEL radiation during user operation. Technical obstacles have been overcome such as suppression of coherent transition radiation from the imaging screen, the continuous image acquisition and processing with the bunch train repetition rate of 10Hz. The monitor, which provides the longitudinal bunch profile and length, has been used routinely at FLASH. In this paper, we present the setup and operation of the longitudinal bunch profile monitor as well as the performance during user operation.

TUPC38	Longitudinal Profile Monitor Using Smith-Purcell Radiation: Recent Results from the E-203 Collaboration	radiation, longitudinal, SLAC, background	464
	N. Delerue, J. Barros, S. Le Corre, M. Vieille Grosjean LAL, Orsay, France H.L. Andrews LANL, Los Alamos, New Mexico, USA F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, C. Perry, A. Reichold, S. Stevenson JAI, Oxford, United Kingdom V. Bharadwaj, C.I. Clarke SLAC, Menlo Park, California, USA N. Fuster Martinez IFIC, Valencia, Spain M. Labat SOLEIL, Gif-sur-Yvette, France
	Funding: Financial support from the John Adams Institute, the Fell Fund (University of Oxford), the Université Paris-Sud (programme 'Attractivité') and the French ANR (contract ANR-12-JS05-0003-01). We report on recent measurements made at FACET by the E-203 collaboration to test a longitudinal bunch profile monitor based on Coherent Smith-Purcell radiation. The capacity of this monitor to resolve sub-picosecond bunches will be shown as well as a comparison of profile reconstructed for different beam compression settings. We will also present recent electromagnetic simulations of the interactions between the beam and the grating as well as the expected resolution of such monitor. Comparison between Coherent Smith-Purcell radiation measurement and those made with other techniques will also be discussed. Finally future upgrades of the experiment and steps toward the construction of a single shot longitudinal profile monitor will be presented.

TUPC40	Bunch Length Measurements Using Correlation Theory in Incoherent Optical Transition Radiation	OTR, radiation, longitudinal, laser	471
	B. Smit, F. Frei, R. Ischebeck, G.L. Orlandi, V. Schlott PSI, Villigen PSI, Switzerland
	Funding: Paul Scherrer Institut (PSI) As Free Electron Lasers create ultra-short bunch lengths, the longitudinal diagnostic for such femto-second bunches becomes more difficult. We suggest a bunch length method using the spectral analysis of incoherent Optical Transition Radiation (OTR) in the visible frequency domain. The frequency response of OTR is taken by inserting an aluminium coated silicon wafer into the electron beam. The OTR light is collected with mirror optics into an optical fibre, which is coupled to a spectrometer (334 THz to 1500 THz). The resolution of the spectrometer allows us to measure bunch length lower than 100 fs rms. Bunch length was varied from 100 femto-seconds down to a few femto-seconds. The spectral response of Optical Transition Radiation (OTR) showed an increase of the correlation between neighbouring frequencies as bunch length was reduced.

TUPC43	Bunch Length Measurement With Streak Camera At SSRF Storage Ring	longitudinal, storage-ring, synchrotron, diagnostics	478
	J. Chen, Z.C. Chen, Y.B. Leng, K.R. Ye, R.X. Yuan SINAP, Shanghai, People's Republic of China
	A streak camera is installed to measure the bunch length of storage ring at SSRF. The principle, structure, configuration and error analysis of the measurement is introduced. Some result of the measurement are analysed to explain the physical meaning of beam status. The system is used in daily operation and machine study at SSRF.

TUPC47	Simulation for Radiation Field Caused by Beam Loss of C-ADS Injector II	proton, photon, beam-losses, radiation	489
	G. Ren, W. Li, Y. Li USTC/NSRL, Hefei, Anhui, People's Republic of China M. Zeng Tsinghua University, Beijing, People's Republic of China
	CADS is a Chinese ADS(Accelerator Driven Sub-critical System) project. Its injector is a high current, full superconducting proton accelerator. For such a facility, a BLM system is necessary, especially in low energy segments. This paper presents some basic simulation for 10MeV proton by Monte Carlo program FLUKA, as well as the distributions we got about different secondary particles in three aspects: angular, energy spectrum and current. These results are helpful to select the detector type and its location, determine its dynamic range matching different requirements for both fast and slow beam loss. This paper also analyzes the major impact of the background, such as superconducting cavity X radiation and radiation caused by material activation. This work is meaningful in BLM system research.

TUPF02	Secondary Emission Monitor for keV Ion and Antiproton Beams	MCP, antiproton, CERN, ion	495
	A.G. Sosa, E. Bravin, A. Jeff CERN, Geneva, Switzerland J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1. Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 10⁷ and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN. This is then used for a characterization of the monitor with regard to its possible future use at different facilities. Measurements at the AD carried out with the AEgIS collaboration.
	Poster TUPF02 [1.934 MB]

TUPF06	2D Wire Grid Integrated with Faraday Cup for Low Energy H⁻ Beam Analysis at Siemens Novel Electrostatic Accelerator	ion, ion-source, simulation, plasma	507
	H. von Jagwitz-Biegnitz JAI, Oxford, United Kingdom P. Beasley, O. Heid Siemens AG, Erlangen, Germany D.C. Faircloth STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom A.J. Holmes Marcham Scientific Ltd, Hungerford, United Kingdom R.G. Selway Inspired Engineering Ltd, Climping, United Kingdom
	A wire grid with 21 wires each vertically and horizontally with a spacing of 1 mm has been developed for beam analysis at Siemens' novel electrostatic accelerator. The wire grid is integrated in a Faraday Cup and profile measurements can therefore be combined with current measurements. The grid is used to analyse the 10 keV H⁻ beam coming from the ion source and the obtained beam parameters will be used as input for simulations of the beam transport in the accelerator. All 42 wires can be read out simultaneously with a multi-channel precision electrometer and the data can be fitted instantly with LabVIEW code that was developed for this purpose. This paper reports on some details of the mechanical design and the data analysis procedure in LabVIEW as well as some results of first measurements at the novel accelerator.

TUPF07	Covariance and Temporal Causality in the Transition Radiation Emission by an Electron Bunch	radiation, transverse, longitudinal, ITY	511
	G.L. Orlandi PSI, Villigen PSI, Switzerland
	A model of the transition radiation emission by a N electron bunch must conform to covariance and causality. The covariance of the charge density must imprint the transition radiation energy spectrum via a proper formulation of the charge form factor. The emission phases of the radiation pulse must be causality correlated with the temporal sequence of the N electron collisions onto the metallic screen. Covariance and temporal causality are the two faces of the same coin: failing in implementing one of the two constraints into the model necessarily implies betraying the other one. The main formal aspects of a covariance and temporal-causality consistent formulation of the transition radiation energy spectrum by an N electron beam are here described. In the case of a transition radiator with a round surface, explicit formal results are presented.

TUPF08	Characterization of Compressed Bunches in the SwissFEL Injector Test Facility	longitudinal, transverse, simulation, acceleration	515
	G.L. Orlandi, M. Aiba, F. Baerenbold, S. Bettoni, B. Beutner, H. Brands, P. Craievich, F. Frei, R. Ischebeck, E. Prat, T. Schietinger, V. Schlott PSI, Villigen PSI, Switzerland
	The quality of the beam transverse emittance at the cathode and the uniformity of the longitudinal compression of the electron bunch are essential for the lasing efficiency of a Free Electron Laser. In SwissFEL the longitudinal compression of the electron beam is performed by means of two magnetic chicanes and an off-crest acceleration scheme. The curvature induced on the beam longitudinal phase-space during the compression can be compensated by means of an X-band cavity. The beam longitudinal phase-space can be experimentally characterized by means of a Transverse Deflecting Cavity (TDC) and a profile monitor in a dispersive section. Longitudinal phase-space measurements at the SwissFEL Injector Test Facility under compression with and without X-band linearizer are presented. In addition, energy spread measurements done by monitoring the Synchrotron Radiation (SR) emitted by the electron beam in the dispersive section of the chicane are shown. A comparison with numerical simulations is presented.

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

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

TUPF26	Laser-Based Beam Instrumentation R&D within LA3NET	laser, target, diagnostics, acceleration	567
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: LA³NET is funded by the European Commission under Grant Agreement Number 289191. Within LA3NET, Laser Applications for Accelerators are being developed by an international NETwork of more than 30 partner institutions from across the world. Laser-based beam instrumentation is at the core of this EU-funded project which will train 17 fellows during its four year project duration. In this contribution, we will present the consortium's recent research results in beam diagnostics, ranging from development of a laser velocimeter and laser emittance meter, over measurement of the bunch shape with electro-optical sampling in an electron accelerator and precision determination of electron beam energy with Compton backscattered laser photons to measurement of electron bunches with a time resolution of better than 20 femtoseconds. We will also provide a summary of past training events organized by the consortium and give an overview of future workshops, conferences and schools.

TUPF33	Electron Beam Diagnostics Using Radiation from a Free Electron Laser	radiation, space-charge, plasma, FEL	593
	M. Arbel H.I.T., Holon, Israel A. Eichenbaum Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
	In most devices based on a high energy electron beam, which used for electromagnetic radiation production, great efforts are focused on the electron beam quality improvement. This is the case in a Free-Electron Laser (FEL) where electron beam with a low normalized emittance is required. Thus, diagnostic tools are required to investigate e-beam properties, such as beam emittance, longitudinal space charge, energy spread and velocity spread. In this paper we present analysis of radiation measurements obtained from a pre-bunched e-beam FEL. The measurements were made for a wide range of frequencies and for beam currents from low currents to high currents, where space charge effects can not neglected. We apply a frequency domain formulation to analyze the measured radiation. The spectral signature of the radiation emission obtained from a pre-bunched e-beam can provide vital information on e-beam properties. We show that a rigorous analysis of the measured radiation, allows characterization of the e-beam parameters. This analysis can provide some insights to the development of e-beam accelerators and radiation sources devices and to help physicists interpreting radiated signals.

TUPF34	Resonant TE Wave Measurement of Electron Cloud Density Using Multiple Sidebands	resonance, simulation, positron, pick-up	597
	J.P. Sikora, J.A. Crittenden Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S. De Santis LBNL, Berkeley, California, USA A.J. Tencate ISU, Pocatello, Idaho, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. A change in electron cloud (EC) density will change the resonant frequency of a section of beam-pipe. With a fixed drive frequency, the resulting dynamic phase shift across the resonant section will include the convolution of the frequency shift with the impulse response of the resonance. The effect of the convolution on the calculated modulation sidebands is in agreement with measured data, including the absolute value of the EC density obtained from ECLOUD simulations. These measurements were made at the Cornell Electron Storage Ring (CESR) which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.
	Poster TUPF34 [2.423 MB]

TUPF35	Resonant TE Wave Measurement of Electron Cloud Density Using Phase Detection	resonance, positron, storage-ring, damping	601
	J.P. Sikora Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S. De Santis LBNL, Berkeley, California, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. The resonant TE wave technique can use modulation sidebands for the calculation of electron cloud (EC) density. An alternative is to mix the drive and received signals to form a phase detector. Using this technique, the phase shift across the resonant section of beam-pipe can be observed directly on an oscilloscope. The growth and decay of the EC density has a time constant of roughly 100 ns, while the measured phase shift will include a convolution of the EC density with the impulse response of the resonant beam-pipe - typically about 500 ns. So any estimate of the growth/decay of the cloud requires deconvolution of the measured signal with the response time of the resonance. We have also used this technique to look for evidence of EC density with a lifetime that is long compare to the revolution period of the stored beam. These measurements were made at the Cornell Electron Storage Ring (CESR) which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.
	Poster TUPF35 [2.554 MB]

TUPF36	Analysis of Modulation Signals Generated in the TE Wave Detection Method For Electron Cloud Measurements	resonance, vacuum, BPM, pick-up	605
	S. De Santis LBNL, Berkeley, California, USA J.P. Sikora Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by the U.S. Department of Energy and by the US National Science Foundation under Contracts No. DE-AC02-05CH11231, DE-FC02-08ER41538, DE-SC0006505, PHY-0734867, PHY-1002467. The evaluation of the electron cloud density in storage rings by measuring its effects on the transmission of electromagnetic signals across portions of the beampipe is a widely used technique and the most suited for measurements over extended regions. Recent results show that in a majority of cases the RF signal transmission takes place by coupling to standing waves excited in the vacuum chamber. In such a case the effect of a varying cloud density is a simultaneous amplitude, phase and frequency modulation of a fixed frequency drive signal. The characteristics of the modulation depend not only on the cloud density values and spatial distribution, but also on its temporal evolution and on the damping time of the standing waves. In this paper we evaluate the relationship between measured modulation sidebands amplitude and the electron cloud density when cloud and electromagnetic resonance rise and fall times are of the same order of magnitude, as it is the case in the accelerators where we have conducted our experiments.

WEAL2	Extremely Low Emittance Beam Size Diagnostics with Sub-Micrometer Resolution Using Optical Transition Radiation	OTR, laser, vacuum, transverse	615
	K.O. Kruchinin, S.T. Boogert, P. Karataev, L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom A.S. Aryshev, M.V. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan B. Bolzon The University of Liverpool, Liverpool, United Kingdom B. Bolzon, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland
	Transverse electron beam diagnostics is crucial for stable and reliable operation of the future electron-positron linear colliders such as CLIC or Higgs Factory. The-state-of-the-art in transverse beam diagnostics is based on the laser-wire technology. However, it requires a high power laser significantly increases the cost of the laser-wire system. Therefore, a simpler and relatively inexpensive method is required. A beam profile monitor based on Optical Transition Radiation (OTR) is very promising. The resolution of conventional OTR monitor is defined by a root-mean-square of the so-called Point Spread Function (PSF). In optical wavelength range the resolution is diffraction limited down to a few micrometers. However, in * we demonstrated that the OTR PSF has a structure which visibility can be used to monitor vertical beam size with sub-micrometer resolution. In this report we shall represent the recent experimental results of a micron-scale beam size measurement. We shall describe the entire method including calibration procedure, new analysis, and calculation of uncertainties. We shall discuss the hardware status and future plans. * P. Karataev et al., Physical Review Letters 107, 174801 (2011).
	Slides WEAL2 [5.120 MB]

WEAL3	Diffraction Radiation Test at CesrTA for Non-Intercepting Micron-Scale Beam Size Measurement	target, radiation, CLIC, CERN	619
	L.M. Bobb, E. Bravin, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland T. Aumeyr, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom M.G. Billing, J.V. Conway Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L.M. Bobb JAI, Egham, Surrey, United Kingdom
	Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. DR can therefore be used to develop non-invasive diagnostic tools. To achieve the micron-scale resolution required to measure the transverse (vertical) beam size using incoherent DR in CLIC, DR in UV and X-ray spectral-range must be investigated. Experimental validation of such a scheme is ongoing at CesrTA at Cornell University, USA. Here we report on the test using 0.5 mm and 1 mm target apertures on a 2.1 GeV electron beam and 400 nm wavelength.
	Slides WEAL3 [2.893 MB]

WEPC05	The ELENA Beam Diagnostics Systems	antiproton, pick-up, proton, CERN	664
	G. Tranquille CERN, Geneva, Switzerland
	The Extra Low ENergy Antiproton ring (ELENA) to be built at CERN is aimed at substantially increasing the number of antiprotons to the low energy antiproton physics community. It will be a small machine which will decelerate low intensity beams (<4x10⁷) from 5.3 MeV to 100 keV and will be equipped with an electron cooler to avoid beam losses during the deceleration and to significantly reduce beam phase space at extraction. To measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and all the way to the experiments, many systems will be needed to ensure that the desired beam characteristics are obtained. Particular attention needs to be paid to the performance of the electron cooler which depends on reliable instrumentation in order to efficiently cool the antiprotons. This contribution will present the different monitors that have been proposed to measure the various beam parameters as well as some of the developments going on to further improve the ELENA diagnostics.
	Poster WEPC05 [1.767 MB]

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

WEPC32	Past, Present and Future Aspects of Laser-Based Synchronization at FLASH	laser, controls, DESY, FEL	753
	S. Schulz, M. Bousonville, M.K. Czwalinna, M. Felber, M. Heuer, T. Lamb, J.M. Müller, P. Peier, S. Ruzin, H. Schlarb, B. Steffen, C. Sydlo, F. Zummack DESY, Hamburg, Germany T. Kozak, P. Predki TUL-DMCS, Łódź, Poland A. Kuhl Uni HH, Hamburg, Germany
	Free-electron lasers, like FLASH and the upcoming European XFEL, are capable of producing XUV and X-ray pulses of a few femtoseconds duration. For time-resolved pump-probe experiments and the externally seeded operation mode it is crucial not only to stabilize the arrival time of the electron bunches, but also to achieve a synchronization accuracy of external lasers on the same timescale. This can only be realized with a laser-based synchronization infrastructure. At FLASH, a periodic femtosecond laser pulse train is transmitted over actively stabilized optical fibers to the critical subsystems. In this paper we report on the present status and performance of the system, as well as its imminent upgrades and new installations. These include the connection of FLASH2, electron bunch arrival time monitors for low charges, a new master laser pulse distribution scheme, all-optical synchronization of the pump-probe laser and arrival time measurements of the UV pulses on the e-gun photocathode. Along with the coming connection of the acceleration modules to the master laser and the switch of the low-level hardware to the uTCA platform, an outlook to improved feedback strategies is given.

WEPC35	Progress Report of the Spectral Decoding Based EOS with Organic Pockels EO Crystals	laser, radiation, background, LEFT	765
	Y. Okayasu, S. Matsubara, H. Tomizawa JASRI/SPring-8, Hyogo-ken, Japan T. Matsukawa, H. Minamide RIKEN ASI, Sendai, Miyagi, Japan K. Ogawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	Funding: Grant-in-Aid for Scientific Research (Japan Society for the Promotion of Science, Grants No. 20612024 and No. 23360045) So far, the temporal structure of ultrashort electron bunches has been extensively investigated by various kinds of electro-optic sampling (EOS) techniques, such as temporal, spectral and spatial decoding method, at several FEL accelerator facilities since early 2000’s. Inorganic Pockels EO crystals, i.e., GaP and ZnTe, have been generally utilized for the EOS. On the other hand, since mid-1980’s, organic nonlinear optical materials have been extensively investigated and DAST, which has fast temporal response in the EO effect, was developed in 1986. DAST is transparent in visible near to IR wavelength range and absorbent in 0.8-1.3 THz. We introduced the DAST crystal into the EOS and successfully demonstrated the first observation of the bunch charge distribution at the EUV-FEL accelerator, SPring-8 on February 2012*. Through the previous experiment, it is found that the EO signal intensity was gradually decreased. On March and April 2013, we prepared DAST crystals with variety of thickness and succeeded to compare EO signal intensities with different bunch charges. Recent results of both optical and structural analysis will be reported in addition to experimental results. 4-N, N-dimethylamino-4’-N’-methyl stilbazolium tosylate S. Okada et al., Japan Patent Application 61-192404 (1986) *Y. Okayasu et al., Phys. Rev. ST Accel. Beams 16, 052801 (2013)

WEPC36	Development of Electron Bunch Compression Monitors for SwissFEL	radiation, longitudinal, synchrotron, transverse	769
	F. Frei, B. Beutner, I. Gorgisyan, R. Ischebeck, G.L. Orlandi, P. Peier, E. Prat, V. Schlott, B. Smit PSI, Villigen PSI, Switzerland P. Peier DESY, Hamburg, Germany
	SwissFEL will be a hard x-ray fourth generation light source to be built at Paul Scherrer Institut (PSI), Switzerland. In SwissFEL the electron bunches will be produced with a length of 3ps and will then be compressed by a factor of more than 1000 down to a few fs in order to generate ultra short x-ray pulses. Therefore reliable, accurate and noninvasive longitudinal diagnostic is essential after each compressing stage. In order to meet the requirements of this machine, new monitors have to be developed. We will present recent results of setups that measure electro-magnetic radiation, namely edge, synchrotron and diffraction radiation, emitted by the electron bunches (far field, spectral domain). These monitors are tested in the SwissFEL Injector Test Facility. A state of the art S-band Transverse Deflecting Cavity together with a Screen Monitor is used for calibration.

WEPC41	Comparative Analysis of Different Electro-Optical Intensity Modulator Candidates for the New 40 GHz Bunch Arrival Time Monitor System for FLASH and European XFEL	laser, pick-up, insertion, free-electron-laser	782
	A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany M.K. Czwalinna, C. Gerth, H. Schlarb, C. Sydlo DESY, Hamburg, Germany S. Schnepp ETH Zurich, Institute of Electromagnetic Fields (IFH), Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: The work is supported by Federal Ministry of Education and Research of Germany (BMBF) within FSP 301 under the contract numbers 05K10GU2 and 05K10RDA. The currently installed Bunch Arrival time Monitors (BAMs) at the Free electron LASer in Hamburg (FLASH) achieved a time resolution of less than 10 fs for bunch charges higher than 500 pC. In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With these BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz are designed and manufactured. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new BAM system also requires new EOMs for the electro-optical frontend. The available selection of commercial EOM candidates for the new frontend is very limited. In this paper we present a comparison between different EOM candidates for the new electro optical frontend. A. Angelovski et al. Proceedings Phys. Rev ST AB, DOI:10.1103/PhysRevSTAB.15.112803
	Poster WEPC41 [0.619 MB]

WEPF01	Alignment of a Nozzle-Skimmer System for a Non Invasive Gas Jet Based Beam Profile Monitor	alignment, laser, vacuum, ion	803
	V. Tzoganis, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by EU under contract 215080, Helmholtz Association and GSI under contract VH-BG-328, STFC under the Cockcroft Institute Core Grant No.ST/G008248/1 and a Liverpool - Riken fellowship. A non-invasive gas jet-based beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This shall allow monitoring ultra-low energy, as well as high energy particle beams in a way that causes least disturbance to both, primary beam and accelerator vacuum. In this setup a nozzle-skimmer system is used to generate a thin supersonic curtain-shaped gas jet. However, very small diameters of both, the gas inlet nozzle and subsequent skimmers, required to shape the jet, have caused problems in monitor operation in the past. Here, an image processing based technique is presented which follows after careful manual initial alignment using a laser beam. An algorithm has been implemented in Labview and offers a semi-automated and straightforward solution for all previously encountered alignment issues. The procedure is presented in detail and experimental results are shown.
	Poster WEPF01 [0.863 MB]

WEPF03	Scintillating Screen Monitors for Transverse Electron Beam Profile Diagnostics at the European XFEL	XFEL, OTR, transverse, DESY	807
	Ch. Wiebers, M. Holz, G. Kube, D. Nölle, G. Priebe, H.-Ch. Schröder DESY, Hamburg, Germany
	Transverse beam profile diagnostics in modern electron linear accelerators like FELs or injector LINACs are mainly based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern LINAC based 4th generation light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As a consequence, for the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. The LYSO:Ce screens are oriented such that coherent OTR generated at the screen boundaries will be geometrically suppressed. An additional advantage is that the imaging optics operate in Scheimpflug condition thus adjusting the plane of sharp focus with respect to the CCD chip and significantly increasing the apparent depth of field. This report gives an overview of the measuring principle and the monitor setup together with results of laboratory test measurements and a first prototype test at FLASH (DESY, Hamburg).

WEPF05	An Electron Beam Detector for the FLASH II Beam Dump	radiation, vacuum, target, laser	814
	F. Perlick, J.D. Good, N. Leuschner, M. Sachwitz DESY Zeuthen, Zeuthen, Germany G. Kube, M. Schmitz, K. Wittenburg, T. Wohlenberg DESY, Hamburg, Germany
	For the electron absorber at FLASH II a detector is developed to control the position, dimensions and profile of the electron beam. Scintillation light, emitted from a luminescent screen in front of the dump window, is reflected by a mirror, located in 2 m distance from the screen, and passes through a vacuum window. Two different optical systems will be installed redundantly for beam image transfer: a conventional lens-mirror-system and a system using a radiation-hard optical fibre bundle. A CCD camera, located in one and a half meter distance from the beam line, is used for the optical analysis. An experimental setup, where the terms of installation of the components correspond to the FLASH accelerator, has been built up in a lab to coordinate the interaction of the screen with the components of the optical system. It was shown that the resolution of the lens-mirror-system is about one line pair per millimeter. An experiment is set up to test the impact of radiation on the optical qualities of the fibre optic bundle by installing it onto a “radioactive hot spot” at the bunch compressor in the FLASH accelerator.
	Poster WEPF05 [1.926 MB]

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

WEPF14	A New Low Intensity Beam Profile Monitor for SPIRAL2	MCP, SPIRAL2, simulation, permanent-magnet	841
	J.L. Vignet, P. Gangnant, E. Guéroult, J. Pancin GANIL, Caen, France
	In order to obtain profiles of SPIRAL 2 ion beams, several beam profile monitors are presently being developed at GANIL. One of them is a low-intensity beam-profile monitor (EFM). This Emission-Foil Monitor (EFM) will be used in the radioactive beam lines of SPIRAL2 and in the experimental rooms of this new facility. The ions produce secondary electrons when they are stopped in an aluminium emissive foil. The electrons are then guided in an electric field placed parallel to a magnetic field in a double-stage microchannel plate (MCP). A 2D pixelated pad plane placed below the MCP is then used to collect the signal. The magnetic field created by permanent magnets in a closed magnetic circuit configuration permits the beam-profile reconstruction to be achieved with good resolution. The EFM can visualize beam-profile intensities between only a few pps to as much as 10⁹ pps and with energies as low as several keV. This profiler has been under development since 2011 and is actually manufactured. For the signal acquisition, a new dedicated electronics system will be employed. Recent results of this monitor and its associated electronics will be presented here.

WEPF18	Zemax Simulations of Diffraction and Transition Radiation	simulation, OTR, radiation, target	852
	T. Aumeyr, P. Karataev JAI, Egham, Surrey, United Kingdom M.G. Billing Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland
	Diffraction Radiation (DR) and Transition Radiation (TR) are produced when a relativistic charged particle moves in the vicinity of a medium or through a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of DR/TR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using DR or TR. This paper reports on how numerical simulations using Zemax can be used to study such a system.
	Poster WEPF18 [0.573 MB]

WEPF21	Scanning Wire Beam Position Monitor for Alignment of a High Brightness Inverse-Compton X-ray Source	laser, scattering, free-electron-laser, alignment	856
	M.R. Hadmack, E.B. Szarmes University of Hawaii, Honolulu, HI, USA
	Funding: US Department of Homeland Security DNDO ARI program GRANT NO. 2010-DN-077-ARI045-02 The Free-Electron Laser Laboratory at the University of Hawaii has constructed and tested a scanning wire beam position monitor to aid the alignment and optimization of a high spectral brightness inverse-Compton scattering X-ray source. X-rays are produced by colliding the 40 MeV electron beam from a pulsed S-band LINAC with infrared laser pulses from a mode-locked free-electron laser driven by the same electron beam. The electron and laser beams are focused to 60 micron diameters at the interaction point to achieve high scattering efficiency. This wire-scanner allows for high resolution measurements of the size and position of both the laser and electron beams at the interaction point to verify spatial coincidence. Time resolved measurements of secondary emission current allow us to monitor the transverse spatial evolution of the e-beam throughout the duration of a 4 microsecond macropulse while the laser is simultaneously profiled by pyrometer measurement of the occulted infrared beam. Using this apparatus we have demonstrated that the electron and laser beams can be co-aligned with a precision better than 10 microns as required to maximize X-ray yield.
	Poster WEPF21 [14.675 MB]

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

WEPF24	Charge Monitors at the Relativistic Electron Gun for Atomic Exploration – REGAE	laser, diagnostics, DESY, gun	868
	H. Delsim-Hashemi, K. Flöttmann, M. Seebach DESY, Hamburg, Germany S. Bayesteh Uni HH, Hamburg, Germany
	A new linac is commissioned at DESY mainly as the electron source for femtosecond electron diffraction facility REGAE (Relativistic Electron Gun for Atomic Exploration). REGAE comprises a photo-cathode gun followed by normal conducting 1.5 cell rf-cavity to provide sub pC charge electron-bunches of 2-5 MeV with a coherence length of 30nm. In order to produce and maintain such electron bunches, sophisticated single-shot diagnostics are desired e.g. emittance, energy, energy-spread and bunch-length measurement. There are three methods at REGAE for charge measurement. The most routine method is based on Faraday-cups that are distributed along machine and can provide charge reading down to ~50 fC. The second method, which is non-destructive, is a cavity based antenna that measures beam induced fields. A third method is based on beam-profile measurement diagnostics. By proper calibration of integral intensity that arrives at detector one can measure charges down to fC level. The last method has the potential to reach the limit of few electrons charge when state-of-the-art intensifiers are used in profile monitors.

WEPF27	Coherent Ultraviolet Radiation Measurements of Laser Induced Bunching in a Seeded FEL	radiation, laser, bunching, FEL	879
	M. Veronese, A. Abrami, E. Allaria, M. Ferianis, E. Ferrari, M. Trovò Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy F. Cianciosi ESRF, Grenoble, France
	Optimization of the bunching process in a seeded FEL like FERMI@Elettra is an important aspect for machine operation. In this paper we discuss about the power detection of coherent radiation in the UV range as a valuable method for optimizing the bunching induced by the seeding process on the electron beam. Experimental results obtained at FERMI@Elettra are presented here. Measurements of UV coherent transition and diffraction radiation have been used to quantify the bunching produced by the seed laser at lower laser harmonics. The dependence of the laser induced CUVTR signal on various parameters is experimentally studied. Future upgrades and possibilities for bunching measurements at shortest wavelengths are also discussed.

WEPF34	Accurate Measurement of Small Electron Beam Currents at the MLS Electron Storage Ring	storage-ring, synchrotron, synchrotron-radiation, radiation	903
	R. Klein, G. Brandt, D. Herzog, R. Thornagel PTB, Berlin, Germany
	The PTB, the German metrology institute, utilizes the electron storage ring MLS in Berlin Adlershof for the realization of the radiometric units in ultraviolet and vacuum ultraviolet spectral range. For this purpose the MLS can be operated as a primary source standard of calculable synchrotron radiation with very flexible parameters, especially in terms of electron beam energy and electron beam current. We report on improvements in the measurement of the electron beam current in the nA and pA range. In this range the electron beam current can be very accurately measured by counting the stored electrons.

WEPF36	X-ray Cherenkov Radiation as a Source for Relativistic Charged Particle Beam Diagnostics	radiation, polarization, photon, target	910
	A.S. Konkov, A.S. Gogolev, A. Potylitsyn TPU, Tomsk, Russia P. Karataev Royal Holloway, University of London, Surrey, United Kingdom
	Funding: The work was partially supported by Russian Ministry of Science and Education within the grant No. 14.B37.21.0912. Recent progress in development of accelerator technology for future linear colliders and X-ray free electron lasers has generated an interest in developing novel diagnostics equipment with resolution surpassing the unique beam parameters. Cherenkov radiation (CR) in the X-ray region in the vicinity of the absorption edges is one of the promising sources for relativistic charged particle beam diagnostics. In this work we have demonstrated CR characteristics in the X-ray region significantly depend on the energy of the emitted photons, because the CR is only generated in the frequency region in the vicinity of the atomic absorption edges, where the well-known Cherenkov condition is work. This peculiarity can be explained by resonance behaviour of the permittivity in the frequency range. It will result in the fact that the CR will stand out of any other types of polarisation radiation both on intensity and shape of angular distribution giving a unique opportunity to apply this phenomenon for charged particle beam diagnostics.
	Poster WEPF36 [42.675 MB]

THAL3	Charge Distribution Measurements at ALBA	photon, synchrotron, BPM, injection	925
	L. Torino, U. Iriso CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	Two different set-ups are used to perform quantitative measurements of the charge distribution at ALBA. The first consists in a real-time analysis of data coming from the Fast Current Transformer or from the buttons of a Beam Position Monitor installed in the Storage Ring. The second is performed at the diagnostic visible beamline Xanadu, using a Photomultiplier that measures the temporal distribution of synchrotron light. In both cases a quantitative estimation of the charge distribution is obtained after a dedicated data treatment and beam current measurements from the DCCT. We compare results with both methods, and discuss differences and limitations with respect to bunch purity measurements with the Time Correlated Single Photon Counting technique.
	Slides THAL3 [15.369 MB]

Paper

Title

Other Keywords

Page

MOAL4

First Results from the Bunch Arrival-Time Monitor at the SwissFEL Test Injector

pick-up, laser, gun, feedback

8

V.R. Arsov, M.M. Dehler, S. Hunziker, M.G. Kaiser, V. Schlott
PSI, Villigen PSI, Switzerland

Non-destructive electron bunch arrival-time monitors (BAMs) with resolution <10 fs, sensitivity down to 10 pC and high intrinsic bandwidth for double bunch detection are required for reliable operation of SwissFEL. To achieve this ultimate goal, such a monitor based on a Mach-Zehnder electro-optical intensity modulator has been under development at the SwissFEL Test Injector. The high timing precision is derived by a stable pulsed optical reference system. The first BAM is located before the bunch compressor where the bunch energy is 230 MeV and the pulse length is approximately 3 ps. At this position, the bunch arrival time is sensitive to the laser- and gun timing. In this paper, we report on the commissioning of the RF- and optical front ends, the first arrival-time jitter and drift measurements with the entire system, as well as correlation of the arrival-time with different machine and environmental parameters. We achieve a resolution of 20 fs down to 60 pC.

Slides MOAL4 [1.228 MB]

MOBL1

Instrumentation and Results from the SwissFEL Injector Test Facility

radiation, diagnostics, transverse, laser

12

R. Ischebeck, V.R. Arsov, S. Bettoni, B. Beutner, M.M. Dehler, A. Falone, F. Frei, I. Gorgisyan, Ye. Ivanisenko, P.N. Juranic, B. Keil, F. Löhl, G.L. Orlandi, M. Pedrozzi, P. Pollet, E. Prat, T. Schietinger, V. Schlott, B. Smit
PSI, Villigen PSI, Switzerland
P. Peier
DESY, Hamburg, Germany

The SwissFEL Injector Test Facility (SITF) has been equipped with numerous prototype diagnostics (BPMs, screen monitors, wire scanners, optical synchrotron radiation monitor, compression (THz) monitor, bunch arrival time monitor, EO spectral decoding monitor, charge and loss monitor) specifically designed for the low charge SwissFEL operation modes. The design of the diagnostics systems and recent measurement results will be presented.

Slides MOBL1 [35.165 MB]

MOBL3

Electron Bunch Diagnostic at the Upgraded ELBE Accelerator: Status and Challenges

ELBE, laser, diagnostics, pick-up

23

M. Kuntzsch, S. Findeisen, M. Gensch, B.W. Green, J. Hauser, S. Kovalev, U. Lehnert, P. Michel, F. Röser, Ch. Schneider, R. Schurig
HZDR, Dresden, Germany
A. Al-Shemmary, M. Bousonville, M.K. Czwalinna, T. Golz, H. Schlarb, B. Schmidt, S. Schulz, N. Stojanovic, S. Vilcins
DESY, Hamburg, Germany
E. Hass
Uni HH, Hamburg, Germany

Within the ELBE upgrade towards a Center for High Power Radiation Sources (HSQ), a mono energetic positron, a liquid lead photo neutron source and two new THz sources have been installed at the superconducting electron linac at ELBE. A variety of established as well as newly developed electron beam diagnostics were installed and tested. In this paper we want to present first results achieved with the currently existing prototype beam arrival time and bunch compression monitors (BAM, BCM) as well as one versatile EOS set-up. Based on these future developements and upgrades are discussed.

Slides MOBL3 [3.578 MB]

MOCL1

Beam Instrumentation at the Accelerator Test Facility 2

laser, OTR, feedback, emittance

26

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

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

Slides MOCL1 [6.059 MB]

MOPC04

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

emittance, diagnostics, collimation, FEL

49

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

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

MOPC06

Beam Diagnostics System for a Photo-Neutron Source Driven by 15MeV Electron Linac

beam-position, linac, diagnostics, BPM

57

Y.B. Yan, J. Chen, Z.C. Chen, Y.B. Leng, L.Y. Yu, R.X. Yuan, W.M. Zhou
SINAP, Shanghai, People's Republic of China

A photo-neutron source driven by 15MeV electron LINAC is under construction at Shanghai Institute of Applied Physics (SINAP). Several kinds of beam monitors (BPM, Profile and ICT) have been installed. The stripline beam position monitor with eight electrodes was designed, also for energy spread measurement. Due to the multi-bunch operation mode, a custom RF front end was adopted, which down-converts the signal from 2856MHz to 500MHz and then brings it to Libera Single Pass E. The beam position monitor was based on the integrated step-servo motor and GigE Vision camera. For the beam charge measurement we used the ICT from Bergoz and scope from Agilent. The detail of the whole beam diagnostics system development will be reported in this paper.

MOPC07

Design Considerations for a New Beam Diagnostics for Medical Electron Accelerators

diagnostics, transverse, controls, emittance

60

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

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

MOPC22

A New High-Dynamic Range BPM for ELBE with Integrated Differential Current Monitor (DCM)

BPM, ELBE, single-bunch, FEL

104

A. Büchner, B. Lange
HZDR, Dresden, Germany

ELBE is a LINAC electron accelerator for small energies (12 to 50 MeV). It serves as a beam source for many quite different experiments. The recent ELBE upgrade allows electron beams with bunches in the range of single electrons to 1 nC. The maximum beam current is 1.6 mA CW and the repetition rates covering the range from one shot single bunch pulses to 26 MHz CW. The existing BPMs and especially the DCMs which are used for the Machine Protection System cannot handle this wide parameter range. To improve this situation the development of new BPMs / DCMs was necessary. The DCMs measure the difference of the beam current between two stripline sensors and produce an interlock for differences greater 10 microamps. The new BPM electronics system has been designed including the DCM functionality because both BPMs and DCMs use the same stripline sensor signals at 1.3 GHz.

MOPC25

About BPMS to be Used for PAL-XFEL

BPM, pick-up, XFEL, beam-position

112

H. J. Choi, H.-S. Kang, C. Kim, S.H. Kim, S.J. Lee, S.J. Park, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) has been building the X-Ray Free Electron Laser (XFEL), a fourth-generation accelerator, and the construction will be complete in 2015. To successfully construct the XFEL, PAL built an injection test facility (ITF) in 2012, and the facility is in operation. The ITF examines the efficiency of various diagnostic units through extended tests. A BPM is a diagnostic unit that measures the position of an electron bunch. There are various kinds of BPM, and they have different merits and demerits. A user can select any kind of BPM that is appropriate for their purpose, and install it after going through various design and production processes. In order to measure the position of an electron bunch, a cavity BPM is installed at an undulator of PAL-XFEL and a stripline BPM is installed at an accelerator. The efficiency of the stripline BPM was tested at the ITF. The X-band cavity BPM was produced and is being tested at the ITF. This paper aims to introduce the specification and properties of the cavity BPM and stripline BPM to be installed at PAL-XFEL, and explain the physical concept and the way of measuring necessary for designing a stripline pickup.

MOPC33

Status of the Fiber Link Stabilization Units at FLASH

laser, free-electron-laser, FEL, polarization

139

F. Zummack, M.K. Czwalinna, M. Felber, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo
DESY, Hamburg, Germany
S. Jabłoński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

State-of-the-art X-ray photon science with modern free-electron lasers (FEL) like FLASH and the upcoming European X-ray Free-Electron Laser Facility (XFEL) requires timing with femtosecond accuracy. For this purpose a sophisticated pulsed optical synchronization system distributes precise timing via length-stabilized fiber links throughout the entire FEL. Stations to be synchronized comprise bunch arrival time monitors, RF stations and optical cross-correlators for external lasers. The different requirements of all those stations have to be met by one optical link-stabilization-unit (LSU) design, compensating drifts and jitter in the distribution system down to a fs-level. Five years of LSU operation at FLASH have led to numerous enhancements resulting in an elaborate system. This paper presents these enhancements, their impact on synchronization performance and the latest state of the LSUs.

MOPC36

Test of a Non-Invasive Bunch Shape Monitor at GSI High Current LINAC

linac, longitudinal, GSI, MCP

151

P. Forck, C. Dorn, O.K. Kester, P. Kowina, B. Zwicker
GSI, Darmstadt, Germany
O.K. Kester
IAP, Frankfurt am Main, Germany

Funding: The work is funded by European Union FP7 within CRISP.
At the heavy ion LINAC at GSI, a novel scheme of non-invasive Bunch Shape Monitor has been tested with several ion beams at 11.4 MeV/u. The monitor’s principle is based on the analysis of secondary electrons as liberated from the residual gas by the beam impact. These electrons are accelerated by an electrostatic field, transported through a sophisticated electrostatic energy analyzer and an RF-deflector, acting as a time-to-space converter. Finally a MCP amplifies electrons and with a CCD camera the electron distribution is detected. For the applied beam settings this Bunch Shape Monitor is able to obtain longitudinal profiles down to a width of 400 ps with a resolution of 50 ps, corresponding to 2 degree of the 108 MHz accelerating frequency. Systematic parameter studies for the device were performed to demonstrate the applicability and to determine its resolution. The achievements and ongoing improvements for the monitor are discussed.

Poster MOPC36 [2.665 MB]

MOPC37

Longitudinal Bunch Profile Reconstruction Using Broadband Coherent Radiation at FLASH

radiation, longitudinal, transverse, laser

154

E. Hass
Uni HH, Hamburg, Germany
C. Behrens, C. Gerth, B. Schmidt, M. Yan
DESY, Hamburg, Germany
S. Wesch
HZB, Berlin, Germany

The required high peak current in free-electron lasers is realized by longitudinal compression of the electron bunches to sub-picosecond length. Measurement of the absolute spectral intensity of coherent radiation emitted by an electron bunch allows monitoring and reconstruction of the longitudinal bunch profile. To measure coherent radiation in the teraherz and infrared range a in-vacuum coherent radiation intensity spectrometer was developed for the free-electron laser in Hamburg(FLASH). The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels: it can be operated either in short (5-44 um) or in long wavelength mode (45-430 um). Fast parallel readout permits the monitoring of coherent radiation from single electron bunches. Large wavelength coverage and superb absolute calibration of the device allows reconstruction of the longitudinal bunch profile using Kramers-Kronig based phase retrieval technique. The device is used as a bunch length monitor and tuning tool during routine operation at FLASH. Comparative measurements with radio-frequency transverse deflecting structure show excellent agreement of both methods.

MOPC47

Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3

beam-losses, quadrupole, CLIC, simulation

189

E. Nebot Del Busto, S. Mallows, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
E. Branger
Linköping University, Linköping, Sweden
S. Döbert, E.B. Holzer, R.L. Lillestøl, S. Mallows, E. Nebot Del Busto
CERN, Geneva, Switzerland
R.L. Lillestøl
University of Oslo, Oslo, Norway
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the beam, the shielding provided by the different elements of the line, the detector sensitivity and possible saturation effects of both the radiation detectors and electronics.

MOPF06

Beam Profile Monitors at REGAE

diagnostics, photon, optics, SNR

212

H. Delsim-Hashemi, K. Flöttmann
DESY, Hamburg, Germany
S. Bayesteh
Uni HH, Hamburg, Germany

A new linac is commissioned at DESY mainly as the electron source for femtosecond electron diffraction facility REGAE (Relativistic Electron Gun for Atomic Exploration). REGAE enables studies on structural dynamics of atomic transition states occurring in the sub-hundred femtosecond time-scale. REGAE comprises a photo-cathode gun followed by normal conducting 1.5 cell rf-cavity to provide sub pC electron-bunches of 2-5 MeV with a coherence length of 30nm. In order to produce and maintain such electron bunches, sophisticated single-shot diagnostics are desired e.g. emittance, energy, energy-spread and bunch-length measurement. REGAE rep-rate can be up to 50 Hz. This relatively high rep-rate makes it more challenging to deal with low intensity detection especially in single-shot mode. In this contribution the conceptual ideas, realization and results of transversal diagnostics will be presented.

MOPF09

A Gas-Jet Profile Monitor for the CLIC Drive Beam

ion, CLIC, space-charge, focusing

224

A. Jeff, E.B. Holzer, T. Lefèvre
CERN, Geneva, Switzerland
A. Jeff, V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.

MOPF10

Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics

undulator, radiation, CLIC, transverse

228

A. Jeff, T. Lefèvre
CERN, Geneva, Switzerland
A. Jeff, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Jeff, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMAX simulations using the CLIC Drive Beam parameters are shown.

MOPF16

Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System

laser, transverse, OTR, photon

243

L.J. Nevay
JAI, Egham, Surrey, United Kingdom
A.S. Aryshev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
S.T. Boogert, P. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom
L. Corner, R. Walczak
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The laserwire system at the Accelerator Test Facility 2 (ATF2) is a transverse beam profile measurement system capable of measuring a micrometre-size electron beam. We present recent results demonstrating a measured vertical size of 1.16 ± 0.06 μm and a horizontal size of 110.1 ± 3.8 μm. Due to the high aspect ratio of the electron beam, the natural divergence of the tightly focussed laser beam across the electron beam width requires the use of the full overlap integral to deconvolve the scans. For this to be done accurately, the propagation of the 150 mJ, 167 ps long laser pulses was precisely measured at a scaled virtual interaction point.

MOPF20

Bunch Purity Measurement for BEPCII

synchrotron, photon, synchrotron-radiation, radiation

252

H. Jun, J.S. Cao, J.H. Junhui
IHEP, Beijing, People's Republic of China

The bunch purity is very important for time-resolved experiments. It is determined by the quality of the injection system and Touschek effect. The Beijing Electron-Positron Collider (BEPC) II was constructed for both high energy physics (HEP) and synchrotron radiation (SR) researches. It can be operated in the colliding mode and synchrotron radiation mode. It is planned to measure the beam quality in a short time of several minutes by using a timecorrelated single photon counting method. The method has a time resolution of 450 ps and a dynamic range of five orders of magnitude. In this paper, we describe our experimental set up and give a series of test results for colliding mode. We plan to set up a system which can kick out the unwanted bunches in the next stage.

MOPF30

Novel Diagnostics for Breakdown Studies

CLIC, simulation, klystron, diagnostics

287

M. Jacewicz, Ch. Borgmann, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
J.W. Kovermann
CERN, Geneva, Switzerland

The phenomenon that currently prevents achieving high accelerating gradients in high energy accelerators such as the CLIC linear collider is electrical breakdown at very high electrical field. The ongoing experimental work is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. The CLIC collaboration has commissioned a dedicated 12 GHz test-stand to validate the feasibility of accelerating structures and observe the characteristics of the RF discharges and their eroding effects on the structure. A versatile system for detection of the dark and breakdown currents and light emission is being developed for the test-stand. It consists of a collimation system with an external magnetic spectrometer for measurement of the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. These measurements can be correlated with e.g. the location of the breakdown inside the structure using information from the incident, reflected and transmitted RF powers giving a complete picture of the vacuum breakdown phenomenon.

MOPF31

Design and Performance of the Biased Drift Tube System in the BNL Electron Lens

RHIC, beam-losses, vacuum, ion

291

T.A. Miller, W. Fischer, D.M. Gassner, X. Gu, A.I. Pikin, S. Polizzo, P. Thieberger
BNL, Upton, Long Island, New York, USA
J. Barth
Barth Electronics, Boulder City, USA

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The installation of the Electron Lenses in RHIC will be completed this year. Its design includes a series of drift tubes through which the electron beam copropagates, with the RHIC proton beams. These drift tubes are used to create an electric field gradient to sweep out ions that become trapped within the central magnetic field where the electron beam interacts with the proton beams. These isolated drift tubes are biased by high voltage power supplies. Without a path for the proton beam image currents, high voltages will develop on the drift tubes that can be detrimental to the electron beam and increase the RHIC machine impedance. This paper presents the design of the drift tubes, axial electric field gradient, and the custom high voltage RF bias tees that were designed to provide separate paths for the high frequency image currents and the DC high voltage bias over the same cables. The design and simulation of the bias tee is discussed, as well as RF signals from the proton beam current imaged on the drift tubes, as measured through the bias tees during the commissioning of the blue RHIC beam electron lens this past spring.

Poster MOPF31 [31.237 MB]

TUAL2

Commissioning the New LCLS X-band Transverse Deflecting Cavity with Femtosecond Resolution

FEL, LCLS, undulator, linac

308

P. Krejcik, F.-J. Decker, Y. Ding, J.C. Frisch, Z. Huang, J.R. Lewandowski, H. Loos, J.L. Turner, J.W. Wang, M.-H. Wang, J.J. Welch
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515
The new X-band transverse deflecting cavity began operation in May 2013 and is installed downstream of the LCLS undulator. It is operated at the full 120 Hz beam rate without interfering with the normal FEL operation for the photon users. The deflected beam is observed on the electron beam dump profile monitor, which acts as an energy spectrometer in the vertical plane. We observe, on a pulse by pulse basis, the time resolved energy profile of the spent electron beam from the undulator. The structure is powered from a 50 MW X-band klystron, giving a 48 MV kick to the beam which yields a 1 fs rms time resolution on the screen. We have measured the longitudinal profile of the electron bunches both with the FEL operating and with the lasing suppressed, allowing reconstruction of both the longitudinal profile of the incoming electron beam and the time-resolved profile of the X-ray pulse generated in the FEL. We are immediately able to see whether the bunch is chirped and which parts of the bunch are lasing, giving us new insight into tuning the machine for peak performance. The performance of the system will be presented along with examples of measurements taken during LCLS operation.

Slides TUAL2 [9.210 MB]

TUAL3

Absolute Bunch Length Measurements at Fermi@ELETTRA FEL

radiation, ELETTRA, background, instrumentation

312

R. Appio
MAX-lab, Lund, Sweden
P. Craievich, G. Penco, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
P. Craievich
PSI, Villigen PSI, Switzerland

Electron bunch length measurements are of crucial importance for many types of accelerators, including storage rings, energy recovery linacs, free electron lasers. Many devices and instrumentation have been developed to measure and control the electron bunch length. A very powerful class of diagnostic tools is based on the coherent radiation power emitted by the electron bunch, that allows a non-destructive shot by shot measurement, well suitable for bunch length control feedback implementation. However they usually provide measurements of the bunch length relative variation, and external instrumentation like a transverse RF deflecting cavity is usually needed to calibrate them and to obtain absolute bunch length estimations. In this paper we present a novel experimental methodology to self-calibrate a device based on diffraction radiation from a ceramic gap. We indeed demonstrate the possibility to use coherent radiation based diagnostic to provide absolute measurements of the electron bunch length. We present the theoretical basis of the proposed approach and validate it through a detailed campaign of measurements that have been carried on in the FERMI@Elettra FEL linac.

Slides TUAL3 [1.126 MB]

TUCL1

Overview of Imaging Sensors and Systems Used in Beam Instrumentation

radiation, optics, controls, instrumentation

331

E. Bravin
CERN, Geneva, Switzerland

The presentation will give an overview of applicable image sensors and sensor systems for an application in the beam instrumentation. The overview will cover fast imaging cameras as well as sensors and cameras to be used in radiation fields. The critical parameters will be discussed and measurements presented if available. Frame grabbers and digital cameras will also be included in the presentation.

Slides TUCL1 [8.924 MB]

TUCL3

Gas Electron Multipliers Versus Multi Wire Proportional Chambers

CERN, antiproton, ion, transverse

342

S.C. Duarte Pinto
Delft University of Technology, Opto-electronic Section, Delft, The Netherlands
J. Spanggaard
CERN, Geneva, Switzerland

Gas Electron Multiplication technology is finding more and more applications in beam instrumentation and at CERN these detectors have recently been adapted for use in transverse profile measurements at several of our facilities. In the experimental areas of CERN’s Antiproton Decelerator, low energy Gas Electron Multipliers successfully replaced all Multi-Wire Proportional Chambers in 2012 and another detector type has now been developed for high energy applications in the experimental areas of the SPS, totalling a potential of more than a hundred profile detectors to be replaced by GEM detectors of different types. This paper aims to describe the historical evolution of GEM technology by covering the many different applications but with specific focus on its potential to replace Multi-Wire Proportional Chambers for standard transverse profile measurement.

Slides TUCL3 [3.275 MB]

TUPC03

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

laser, emittance, gun, SASE

353

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

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

Poster TUPC03 [1.076 MB]

TUPC06

Status of Beam Diagnostic Systems for TRIUMF Electron Linac

BPM, diagnostics, target, linac

361

V.A. Verzilov, P.S. Birney, D.P. Cameron, P. Dirksen, J.V. Holek, S.Y. Kajioka, S. Kellogg, M. Lenckowski, M. Minato, W.R. Rawnsley
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
J.M. Abernathy, D. Karlen, D.W. Storey
Victoria University, Victoria, B.C., Canada

TRIUMF laboratory is currently in a phase of the construction of a superconducting 50 MeV 10 mA cw electron LINAC to drive photo-fission based rare radioactive isotope beam (RIB) production. The project imposes certain technical challenges on various accelerator systems including beam diagnostics. In the first place these are a high beam power and strongly varying operating modes ranging from microsecond beam pulses to the cw regime. Diagnostics development interleaves with the construction of the diagnostics instrumentation required for the test facility which delivered the first beam in Fall of 2011. The paper reports the present status of various diagnostics systems along with measurement results obtained at the test facility.

TUPC10

Operation of Diamond Light Source XBPMs with Zero Bias

DIAMOND, photon, synchrotron, beam-position

376

C. Bloomer, G. Rehm
Diamond, Oxfordshire, United Kingdom

Tungsten blade X-ray Beam Position Monitors (XBPMs) have been used at Diamond Light Source since 2007, however a long-standing problem with these devices has been the growth of leakage current through the ceramic insulation within the XBPMs over time, often becoming greater than 10% of the signal current after a few years of operation. The growth of these leakage currents has been found to be exacerbated by the application of a negative bias (-70V) to the tungsten blades, a bias suggested for optimum position sensitivity. This bias is applied in order to accelerate free electrons away from the surface of the blades and to prevent cross-talk, however, we have found that the operation of the XBPMs without bias has negligible impact on our measurements. Removal of the bias has been found to prevent the growth of leakage currents over time, and can also significantly reduce the cost of our signal acquisition by removing the need for a low-current amplifier with a bias supply.

Poster TUPC10 [0.455 MB]

TUPC18

Development of a Highly Efficient Energy Kicker for Longitudinal Bunch-by-Bunch Feedback

kicker, longitudinal, synchrotron, storage-ring

407

M. Masaki, T. Fujita, K. Kobayashi, T. Nakamura, H. Ohkuma, M. Oishi, S. Sasaki, M. Shoji
JASRI/SPring-8, Hyogo-ken, Japan

A highly efficient energy kicker has been developed for longitudinal bunch-by-bunch feedback to suppress synchrotron oscillation of a high-current single electron bunch, and to cure possible longitudinal multi-bunch instability if lower beam energy is to be adopted for emittance reduction and electric power saving in a future upgrade plan of SPring-8. Through the performance test using a prototype kicker, a new water-cooled copper kicker was designed and fabricated, and it has been installed in the storage ring. The new kicker consists of three cells with each cavity length of 96 mm, its resonant frequency of 1.65 GHz, which is 3.25 times of RF frequency of the storage ring, and low Q-factor of 4.2. In beam kick test, the synchrotron oscillation amplitude of 0.64 ps was excited by kick voltage with continuous amplitude modulation at synchrotron frequency when the RF input power was 132 W/3cells. The kick voltage evaluated from the experimental result is 920 V/3cells. Shunt impedance of each kicker cell is estimated as 1.1 kΩ. As we intended, the shunt impedance per length is about three times higher than those of widely used waveguide overloaded cavity type kickers.

Poster TUPC18 [9.117 MB]

TUPC36

First Realization and Performance Study of a Single-Shot Longitudinal Bunch Profile Monitor Utilizing a Transverse Deflecting Structure

longitudinal, FEL, feedback, kicker

456

M. Yan, C. Behrens, C. Gerth, R. Kammering, A. Langner, F. Obier, V. Rybnikov
DESY, Hamburg, Germany
J. Wychowaniak
TUL-DMCS, Łódź, Poland

For the control and optimization of electron beam parameters at modern free-electron lasers (FEL), transverse deflecting structures (TDS) in combination with imaging screens have been widely used as robust longitudinal diagnostics with single-shot capability, high resolution and large dynamic range. At the free-electron laser in Hamburg (FLASH), a longitudinal bunch profile monitor utilizing a TDS has been realized. In combined use with a fast kicker magnet and an off-axis imaging screen, selection and measurement of a single bunch out of the bunch train with bunch spacing down to 1us can be achieved without affecting the remaining bunches which continue to generate FEL radiation during user operation. Technical obstacles have been overcome such as suppression of coherent transition radiation from the imaging screen, the continuous image acquisition and processing with the bunch train repetition rate of 10Hz. The monitor, which provides the longitudinal bunch profile and length, has been used routinely at FLASH. In this paper, we present the setup and operation of the longitudinal bunch profile monitor as well as the performance during user operation.

TUPC38

Longitudinal Profile Monitor Using Smith-Purcell Radiation: Recent Results from the E-203 Collaboration

radiation, longitudinal, SLAC, background

464

N. Delerue, J. Barros, S. Le Corre, M. Vieille Grosjean
LAL, Orsay, France
H.L. Andrews
LANL, Los Alamos, New Mexico, USA
F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, C. Perry, A. Reichold, S. Stevenson
JAI, Oxford, United Kingdom
V. Bharadwaj, C.I. Clarke
SLAC, Menlo Park, California, USA
N. Fuster Martinez
IFIC, Valencia, Spain
M. Labat
SOLEIL, Gif-sur-Yvette, France

Funding: Financial support from the John Adams Institute, the Fell Fund (University of Oxford), the Université Paris-Sud (programme 'Attractivité') and the French ANR (contract ANR-12-JS05-0003-01).
We report on recent measurements made at FACET by the E-203 collaboration to test a longitudinal bunch profile monitor based on Coherent Smith-Purcell radiation. The capacity of this monitor to resolve sub-picosecond bunches will be shown as well as a comparison of profile reconstructed for different beam compression settings. We will also present recent electromagnetic simulations of the interactions between the beam and the grating as well as the expected resolution of such monitor. Comparison between Coherent Smith-Purcell radiation measurement and those made with other techniques will also be discussed. Finally future upgrades of the experiment and steps toward the construction of a single shot longitudinal profile monitor will be presented.

TUPC40

Bunch Length Measurements Using Correlation Theory in Incoherent Optical Transition Radiation

OTR, radiation, longitudinal, laser

471

B. Smit, F. Frei, R. Ischebeck, G.L. Orlandi, V. Schlott
PSI, Villigen PSI, Switzerland

Funding: Paul Scherrer Institut (PSI)
As Free Electron Lasers create ultra-short bunch lengths, the longitudinal diagnostic for such femto-second bunches becomes more difficult. We suggest a bunch length method using the spectral analysis of incoherent Optical Transition Radiation (OTR) in the visible frequency domain. The frequency response of OTR is taken by inserting an aluminium coated silicon wafer into the electron beam. The OTR light is collected with mirror optics into an optical fibre, which is coupled to a spectrometer (334 THz to 1500 THz). The resolution of the spectrometer allows us to measure bunch length lower than 100 fs rms. Bunch length was varied from 100 femto-seconds down to a few femto-seconds. The spectral response of Optical Transition Radiation (OTR) showed an increase of the correlation between neighbouring frequencies as bunch length was reduced.

TUPC43

Bunch Length Measurement With Streak Camera At SSRF Storage Ring

longitudinal, storage-ring, synchrotron, diagnostics

478

J. Chen, Z.C. Chen, Y.B. Leng, K.R. Ye, R.X. Yuan
SINAP, Shanghai, People's Republic of China

A streak camera is installed to measure the bunch length of storage ring at SSRF. The principle, structure, configuration and error analysis of the measurement is introduced. Some result of the measurement are analysed to explain the physical meaning of beam status. The system is used in daily operation and machine study at SSRF.

TUPC47

Simulation for Radiation Field Caused by Beam Loss of C-ADS Injector II

proton, photon, beam-losses, radiation

489

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

CADS is a Chinese ADS(Accelerator Driven Sub-critical System) project. Its injector is a high current, full superconducting proton accelerator. For such a facility, a BLM system is necessary, especially in low energy segments. This paper presents some basic simulation for 10MeV proton by Monte Carlo program FLUKA, as well as the distributions we got about different secondary particles in three aspects: angular, energy spectrum and current. These results are helpful to select the detector type and its location, determine its dynamic range matching different requirements for both fast and slow beam loss. This paper also analyzes the major impact of the background, such as superconducting cavity X radiation and radiation caused by material activation. This work is meaningful in BLM system research.

TUPF02

Secondary Emission Monitor for keV Ion and Antiproton Beams

MCP, antiproton, CERN, ion

495

A.G. Sosa, E. Bravin, A. Jeff
CERN, Geneva, Switzerland
J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 10⁷ and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN*. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.
* Measurements at the AD carried out with the AEgIS collaboration.

Poster TUPF02 [1.934 MB]

TUPF06

2D Wire Grid Integrated with Faraday Cup for Low Energy H⁻ Beam Analysis at Siemens Novel Electrostatic Accelerator

ion, ion-source, simulation, plasma

507

H. von Jagwitz-Biegnitz
JAI, Oxford, United Kingdom
P. Beasley, O. Heid
Siemens AG, Erlangen, Germany
D.C. Faircloth
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
A.J. Holmes
Marcham Scientific Ltd, Hungerford, United Kingdom
R.G. Selway
Inspired Engineering Ltd, Climping, United Kingdom

A wire grid with 21 wires each vertically and horizontally with a spacing of 1 mm has been developed for beam analysis at Siemens' novel electrostatic accelerator. The wire grid is integrated in a Faraday Cup and profile measurements can therefore be combined with current measurements. The grid is used to analyse the 10 keV H⁻ beam coming from the ion source and the obtained beam parameters will be used as input for simulations of the beam transport in the accelerator. All 42 wires can be read out simultaneously with a multi-channel precision electrometer and the data can be fitted instantly with LabVIEW code that was developed for this purpose. This paper reports on some details of the mechanical design and the data analysis procedure in LabVIEW as well as some results of first measurements at the novel accelerator.

TUPF07

Covariance and Temporal Causality in the Transition Radiation Emission by an Electron Bunch

radiation, transverse, longitudinal, ITY

511

G.L. Orlandi
PSI, Villigen PSI, Switzerland

A model of the transition radiation emission by a N electron bunch must conform to covariance and causality. The covariance of the charge density must imprint the transition radiation energy spectrum via a proper formulation of the charge form factor. The emission phases of the radiation pulse must be causality correlated with the temporal sequence of the N electron collisions onto the metallic screen. Covariance and temporal causality are the two faces of the same coin: failing in implementing one of the two constraints into the model necessarily implies betraying the other one. The main formal aspects of a covariance and temporal-causality consistent formulation of the transition radiation energy spectrum by an N electron beam are here described. In the case of a transition radiator with a round surface, explicit formal results are presented.

TUPF08

Characterization of Compressed Bunches in the SwissFEL Injector Test Facility

longitudinal, transverse, simulation, acceleration

515

G.L. Orlandi, M. Aiba, F. Baerenbold, S. Bettoni, B. Beutner, H. Brands, P. Craievich, F. Frei, R. Ischebeck, E. Prat, T. Schietinger, V. Schlott
PSI, Villigen PSI, Switzerland

The quality of the beam transverse emittance at the cathode and the uniformity of the longitudinal compression of the electron bunch are essential for the lasing efficiency of a Free Electron Laser. In SwissFEL the longitudinal compression of the electron beam is performed by means of two magnetic chicanes and an off-crest acceleration scheme. The curvature induced on the beam longitudinal phase-space during the compression can be compensated by means of an X-band cavity. The beam longitudinal phase-space can be experimentally characterized by means of a Transverse Deflecting Cavity (TDC) and a profile monitor in a dispersive section. Longitudinal phase-space measurements at the SwissFEL Injector Test Facility under compression with and without X-band linearizer are presented. In addition, energy spread measurements done by monitoring the Synchrotron Radiation (SR) emitted by the electron beam in the dispersive section of the chicane are shown. A comparison with numerical simulations is presented.

TUPF18

Vertical Undulator Emittance Measurement: A Statistical Approach

undulator, emittance, photon, radiation

543

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

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

Poster TUPF18 [2.090 MB]

TUPF24

Instrumentation for the Proposed Low Energy RHIC Electron Cooling Project

ion, RHIC, diagnostics, emittance

561

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

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

Poster TUPF24 [1.588 MB]

TUPF26

Laser-Based Beam Instrumentation R&D within LA3NET

laser, target, diagnostics, acceleration

567

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: LA³NET is funded by the European Commission under Grant Agreement Number 289191.
Within LA3NET, Laser Applications for Accelerators are being developed by an international NETwork of more than 30 partner institutions from across the world. Laser-based beam instrumentation is at the core of this EU-funded project which will train 17 fellows during its four year project duration. In this contribution, we will present the consortium's recent research results in beam diagnostics, ranging from development of a laser velocimeter and laser emittance meter, over measurement of the bunch shape with electro-optical sampling in an electron accelerator and precision determination of electron beam energy with Compton backscattered laser photons to measurement of electron bunches with a time resolution of better than 20 femtoseconds. We will also provide a summary of past training events organized by the consortium and give an overview of future workshops, conferences and schools.

TUPF33

Electron Beam Diagnostics Using Radiation from a Free Electron Laser

radiation, space-charge, plasma, FEL

593

M. Arbel
H.I.T., Holon, Israel
A. Eichenbaum
Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel

In most devices based on a high energy electron beam, which used for electromagnetic radiation production, great efforts are focused on the electron beam quality improvement. This is the case in a Free-Electron Laser (FEL) where electron beam with a low normalized emittance is required. Thus, diagnostic tools are required to investigate e-beam properties, such as beam emittance, longitudinal space charge, energy spread and velocity spread. In this paper we present analysis of radiation measurements obtained from a pre-bunched e-beam FEL. The measurements were made for a wide range of frequencies and for beam currents from low currents to high currents, where space charge effects can not neglected. We apply a frequency domain formulation to analyze the measured radiation. The spectral signature of the radiation emission obtained from a pre-bunched e-beam can provide vital information on e-beam properties. We show that a rigorous analysis of the measured radiation, allows characterization of the e-beam parameters. This analysis can provide some insights to the development of e-beam accelerators and radiation sources devices and to help physicists interpreting radiated signals.

TUPF34

Resonant TE Wave Measurement of Electron Cloud Density Using Multiple Sidebands

resonance, simulation, positron, pick-up

597

J.P. Sikora, J.A. Crittenden
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S. De Santis
LBNL, Berkeley, California, USA
A.J. Tencate
ISU, Pocatello, Idaho, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
A change in electron cloud (EC) density will change the resonant frequency of a section of beam-pipe. With a fixed drive frequency, the resulting dynamic phase shift across the resonant section will include the convolution of the frequency shift with the impulse response of the resonance. The effect of the convolution on the calculated modulation sidebands is in agreement with measured data, including the absolute value of the EC density obtained from ECLOUD simulations. These measurements were made at the Cornell Electron Storage Ring (CESR) which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.

Poster TUPF34 [2.423 MB]

TUPF35

Resonant TE Wave Measurement of Electron Cloud Density Using Phase Detection

resonance, positron, storage-ring, damping

601

J.P. Sikora
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S. De Santis
LBNL, Berkeley, California, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The resonant TE wave technique can use modulation sidebands for the calculation of electron cloud (EC) density. An alternative is to mix the drive and received signals to form a phase detector. Using this technique, the phase shift across the resonant section of beam-pipe can be observed directly on an oscilloscope. The growth and decay of the EC density has a time constant of roughly 100 ns, while the measured phase shift will include a convolution of the EC density with the impulse response of the resonant beam-pipe - typically about 500 ns. So any estimate of the growth/decay of the cloud requires deconvolution of the measured signal with the response time of the resonance. We have also used this technique to look for evidence of EC density with a lifetime that is long compare to the revolution period of the stored beam. These measurements were made at the Cornell Electron Storage Ring (CESR) which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.

Poster TUPF35 [2.554 MB]

TUPF36

Analysis of Modulation Signals Generated in the TE Wave Detection Method For Electron Cloud Measurements

resonance, vacuum, BPM, pick-up

605

S. De Santis
LBNL, Berkeley, California, USA
J.P. Sikora
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the U.S. Department of Energy and by the US National Science Foundation under Contracts No. DE-AC02-05CH11231, DE-FC02-08ER41538, DE-SC0006505, PHY-0734867, PHY-1002467.
The evaluation of the electron cloud density in storage rings by measuring its effects on the transmission of electromagnetic signals across portions of the beampipe is a widely used technique and the most suited for measurements over extended regions. Recent results show that in a majority of cases the RF signal transmission takes place by coupling to standing waves excited in the vacuum chamber. In such a case the effect of a varying cloud density is a simultaneous amplitude, phase and frequency modulation of a fixed frequency drive signal. The characteristics of the modulation depend not only on the cloud density values and spatial distribution, but also on its temporal evolution and on the damping time of the standing waves. In this paper we evaluate the relationship between measured modulation sidebands amplitude and the electron cloud density when cloud and electromagnetic resonance rise and fall times are of the same order of magnitude, as it is the case in the accelerators where we have conducted our experiments.

WEAL2

Extremely Low Emittance Beam Size Diagnostics with Sub-Micrometer Resolution Using Optical Transition Radiation

OTR, laser, vacuum, transverse

615

K.O. Kruchinin, S.T. Boogert, P. Karataev, L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
A.S. Aryshev, M.V. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
B. Bolzon
The University of Liverpool, Liverpool, United Kingdom
B. Bolzon, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland

Transverse electron beam diagnostics is crucial for stable and reliable operation of the future electron-positron linear colliders such as CLIC or Higgs Factory. The-state-of-the-art in transverse beam diagnostics is based on the laser-wire technology. However, it requires a high power laser significantly increases the cost of the laser-wire system. Therefore, a simpler and relatively inexpensive method is required. A beam profile monitor based on Optical Transition Radiation (OTR) is very promising. The resolution of conventional OTR monitor is defined by a root-mean-square of the so-called Point Spread Function (PSF). In optical wavelength range the resolution is diffraction limited down to a few micrometers. However, in * we demonstrated that the OTR PSF has a structure which visibility can be used to monitor vertical beam size with sub-micrometer resolution. In this report we shall represent the recent experimental results of a micron-scale beam size measurement. We shall describe the entire method including calibration procedure, new analysis, and calculation of uncertainties. We shall discuss the hardware status and future plans.
* P. Karataev et al., Physical Review Letters 107, 174801 (2011).

Slides WEAL2 [5.120 MB]

WEAL3

Diffraction Radiation Test at CesrTA for Non-Intercepting Micron-Scale Beam Size Measurement

target, radiation, CLIC, CERN

619

L.M. Bobb, E. Bravin, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
T. Aumeyr, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
M.G. Billing, J.V. Conway
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L.M. Bobb
JAI, Egham, Surrey, United Kingdom

Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. DR can therefore be used to develop non-invasive diagnostic tools. To achieve the micron-scale resolution required to measure the transverse (vertical) beam size using incoherent DR in CLIC, DR in UV and X-ray spectral-range must be investigated. Experimental validation of such a scheme is ongoing at CesrTA at Cornell University, USA. Here we report on the test using 0.5 mm and 1 mm target apertures on a 2.1 GeV electron beam and 400 nm wavelength.

Slides WEAL3 [2.893 MB]

WEPC05

The ELENA Beam Diagnostics Systems

antiproton, pick-up, proton, CERN

664

G. Tranquille
CERN, Geneva, Switzerland

The Extra Low ENergy Antiproton ring (ELENA) to be built at CERN is aimed at substantially increasing the number of antiprotons to the low energy antiproton physics community. It will be a small machine which will decelerate low intensity beams (<4x10⁷) from 5.3 MeV to 100 keV and will be equipped with an electron cooler to avoid beam losses during the deceleration and to significantly reduce beam phase space at extraction. To measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and all the way to the experiments, many systems will be needed to ensure that the desired beam characteristics are obtained. Particular attention needs to be paid to the performance of the electron cooler which depends on reliable instrumentation in order to efficiently cool the antiprotons. This contribution will present the different monitors that have been proposed to measure the various beam parameters as well as some of the developments going on to further improve the ELENA diagnostics.

Poster WEPC05 [1.767 MB]

WEPC07

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

BPM, controls, coupling, emittance

670

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

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

Poster WEPC07 [1.236 MB]

WEPC32

Past, Present and Future Aspects of Laser-Based Synchronization at FLASH

laser, controls, DESY, FEL

753

S. Schulz, M. Bousonville, M.K. Czwalinna, M. Felber, M. Heuer, T. Lamb, J.M. Müller, P. Peier, S. Ruzin, H. Schlarb, B. Steffen, C. Sydlo, F. Zummack
DESY, Hamburg, Germany
T. Kozak, P. Predki
TUL-DMCS, Łódź, Poland
A. Kuhl
Uni HH, Hamburg, Germany

Free-electron lasers, like FLASH and the upcoming European XFEL, are capable of producing XUV and X-ray pulses of a few femtoseconds duration. For time-resolved pump-probe experiments and the externally seeded operation mode it is crucial not only to stabilize the arrival time of the electron bunches, but also to achieve a synchronization accuracy of external lasers on the same timescale. This can only be realized with a laser-based synchronization infrastructure. At FLASH, a periodic femtosecond laser pulse train is transmitted over actively stabilized optical fibers to the critical subsystems. In this paper we report on the present status and performance of the system, as well as its imminent upgrades and new installations. These include the connection of FLASH2, electron bunch arrival time monitors for low charges, a new master laser pulse distribution scheme, all-optical synchronization of the pump-probe laser and arrival time measurements of the UV pulses on the e-gun photocathode. Along with the coming connection of the acceleration modules to the master laser and the switch of the low-level hardware to the uTCA platform, an outlook to improved feedback strategies is given.

WEPC35

Progress Report of the Spectral Decoding Based EOS with Organic Pockels EO Crystals

laser, radiation, background, LEFT

765

Y. Okayasu, S. Matsubara, H. Tomizawa
JASRI/SPring-8, Hyogo-ken, Japan
T. Matsukawa, H. Minamide
RIKEN ASI, Sendai, Miyagi, Japan
K. Ogawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Funding: Grant-in-Aid for Scientific Research (Japan Society for the Promotion of Science, Grants No. 20612024 and No. 23360045)
So far, the temporal structure of ultrashort electron bunches has been extensively investigated by various kinds of electro-optic sampling (EOS) techniques, such as temporal, spectral and spatial decoding method, at several FEL accelerator facilities since early 2000’s. Inorganic Pockels EO crystals, i.e., GaP and ZnTe, have been generally utilized for the EOS. On the other hand, since mid-1980’s, organic nonlinear optical materials have been extensively investigated and DAST*, which has fast temporal response in the EO effect, was developed in 1986**. DAST is transparent in visible near to IR wavelength range and absorbent in 0.8-1.3 THz. We introduced the DAST crystal into the EOS and successfully demonstrated the first observation of the bunch charge distribution at the EUV-FEL accelerator, SPring-8 on February 2012***. Through the previous experiment, it is found that the EO signal intensity was gradually decreased. On March and April 2013, we prepared DAST crystals with variety of thickness and succeeded to compare EO signal intensities with different bunch charges. Recent results of both optical and structural analysis will be reported in addition to experimental results.
*4-N, N-dimethylamino-4’-N’-methyl stilbazolium tosylate
**S. Okada et al., Japan Patent Application 61-192404 (1986)
***Y. Okayasu et al., Phys. Rev. ST Accel. Beams 16, 052801 (2013)

WEPC36

Development of Electron Bunch Compression Monitors for SwissFEL

radiation, longitudinal, synchrotron, transverse

769

F. Frei, B. Beutner, I. Gorgisyan, R. Ischebeck, G.L. Orlandi, P. Peier, E. Prat, V. Schlott, B. Smit
PSI, Villigen PSI, Switzerland
P. Peier
DESY, Hamburg, Germany

SwissFEL will be a hard x-ray fourth generation light source to be built at Paul Scherrer Institut (PSI), Switzerland. In SwissFEL the electron bunches will be produced with a length of 3ps and will then be compressed by a factor of more than 1000 down to a few fs in order to generate ultra short x-ray pulses. Therefore reliable, accurate and noninvasive longitudinal diagnostic is essential after each compressing stage. In order to meet the requirements of this machine, new monitors have to be developed. We will present recent results of setups that measure electro-magnetic radiation, namely edge, synchrotron and diffraction radiation, emitted by the electron bunches (far field, spectral domain). These monitors are tested in the SwissFEL Injector Test Facility. A state of the art S-band Transverse Deflecting Cavity together with a Screen Monitor is used for calibration.

WEPC41

Comparative Analysis of Different Electro-Optical Intensity Modulator Candidates for the New 40 GHz Bunch Arrival Time Monitor System for FLASH and European XFEL

laser, pick-up, insertion, free-electron-laser

782

A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
M.K. Czwalinna, C. Gerth, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
S. Schnepp
ETH Zurich, Institute of Electromagnetic Fields (IFH), Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: The work is supported by Federal Ministry of Education and Research of Germany (BMBF) within FSP 301 under the contract numbers 05K10GU2 and 05K10RDA.
The currently installed Bunch Arrival time Monitors (BAMs) at the Free electron LASer in Hamburg (FLASH) achieved a time resolution of less than 10 fs for bunch charges higher than 500 pC. In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With these BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz are designed and manufactured*. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new BAM system also requires new EOMs for the electro-optical frontend. The available selection of commercial EOM candidates for the new frontend is very limited. In this paper we present a comparison between different EOM candidates for the new electro optical frontend.
* A. Angelovski et al. Proceedings Phys. Rev ST AB, DOI:10.1103/PhysRevSTAB.15.112803

Poster WEPC41 [0.619 MB]

WEPF01

Alignment of a Nozzle-Skimmer System for a Non Invasive Gas Jet Based Beam Profile Monitor

alignment, laser, vacuum, ion

803

V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by EU under contract 215080, Helmholtz Association and GSI under contract VH-BG-328, STFC under the Cockcroft Institute Core Grant No.ST/G008248/1 and a Liverpool - Riken fellowship.
A non-invasive gas jet-based beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This shall allow monitoring ultra-low energy, as well as high energy particle beams in a way that causes least disturbance to both, primary beam and accelerator vacuum. In this setup a nozzle-skimmer system is used to generate a thin supersonic curtain-shaped gas jet. However, very small diameters of both, the gas inlet nozzle and subsequent skimmers, required to shape the jet, have caused problems in monitor operation in the past. Here, an image processing based technique is presented which follows after careful manual initial alignment using a laser beam. An algorithm has been implemented in Labview and offers a semi-automated and straightforward solution for all previously encountered alignment issues. The procedure is presented in detail and experimental results are shown.

Poster WEPF01 [0.863 MB]

WEPF03

Scintillating Screen Monitors for Transverse Electron Beam Profile Diagnostics at the European XFEL

XFEL, OTR, transverse, DESY

807

Ch. Wiebers, M. Holz, G. Kube, D. Nölle, G. Priebe, H.-Ch. Schröder
DESY, Hamburg, Germany

Transverse beam profile diagnostics in modern electron linear accelerators like FELs or injector LINACs are mainly based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern LINAC based 4th generation light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As a consequence, for the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. The LYSO:Ce screens are oriented such that coherent OTR generated at the screen boundaries will be geometrically suppressed. An additional advantage is that the imaging optics operate in Scheimpflug condition thus adjusting the plane of sharp focus with respect to the CCD chip and significantly increasing the apparent depth of field. This report gives an overview of the measuring principle and the monitor setup together with results of laboratory test measurements and a first prototype test at FLASH (DESY, Hamburg).

WEPF05

An Electron Beam Detector for the FLASH II Beam Dump

radiation, vacuum, target, laser

814

F. Perlick, J.D. Good, N. Leuschner, M. Sachwitz
DESY Zeuthen, Zeuthen, Germany
G. Kube, M. Schmitz, K. Wittenburg, T. Wohlenberg
DESY, Hamburg, Germany

For the electron absorber at FLASH II a detector is developed to control the position, dimensions and profile of the electron beam. Scintillation light, emitted from a luminescent screen in front of the dump window, is reflected by a mirror, located in 2 m distance from the screen, and passes through a vacuum window. Two different optical systems will be installed redundantly for beam image transfer: a conventional lens-mirror-system and a system using a radiation-hard optical fibre bundle. A CCD camera, located in one and a half meter distance from the beam line, is used for the optical analysis. An experimental setup, where the terms of installation of the components correspond to the FLASH accelerator, has been built up in a lab to coordinate the interaction of the screen with the components of the optical system. It was shown that the resolution of the lens-mirror-system is about one line pair per millimeter. An experiment is set up to test the impact of radiation on the optical qualities of the fibre optic bundle by installing it onto a “radioactive hot spot” at the bunch compressor in the FLASH accelerator.

Poster WEPF05 [1.926 MB]

WEPF11

Emittance Measurement Using X-Ray Lenses at the ESRF

emittance, photon, dipole, lattice

833

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

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

WEPF14

A New Low Intensity Beam Profile Monitor for SPIRAL2

MCP, SPIRAL2, simulation, permanent-magnet

841

J.L. Vignet, P. Gangnant, E. Guéroult, J. Pancin
GANIL, Caen, France

In order to obtain profiles of SPIRAL 2 ion beams, several beam profile monitors are presently being developed at GANIL. One of them is a low-intensity beam-profile monitor (EFM). This Emission-Foil Monitor (EFM) will be used in the radioactive beam lines of SPIRAL2 and in the experimental rooms of this new facility. The ions produce secondary electrons when they are stopped in an aluminium emissive foil. The electrons are then guided in an electric field placed parallel to a magnetic field in a double-stage microchannel plate (MCP). A 2D pixelated pad plane placed below the MCP is then used to collect the signal. The magnetic field created by permanent magnets in a closed magnetic circuit configuration permits the beam-profile reconstruction to be achieved with good resolution. The EFM can visualize beam-profile intensities between only a few pps to as much as 10⁹ pps and with energies as low as several keV. This profiler has been under development since 2011 and is actually manufactured. For the signal acquisition, a new dedicated electronics system will be employed. Recent results of this monitor and its associated electronics will be presented here.

WEPF18

Zemax Simulations of Diffraction and Transition Radiation

simulation, OTR, radiation, target

852

T. Aumeyr, P. Karataev
JAI, Egham, Surrey, United Kingdom
M.G. Billing
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland

Diffraction Radiation (DR) and Transition Radiation (TR) are produced when a relativistic charged particle moves in the vicinity of a medium or through a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of DR/TR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using DR or TR. This paper reports on how numerical simulations using Zemax can be used to study such a system.

Poster WEPF18 [0.573 MB]

WEPF21

Scanning Wire Beam Position Monitor for Alignment of a High Brightness Inverse-Compton X-ray Source

laser, scattering, free-electron-laser, alignment

856

M.R. Hadmack, E.B. Szarmes
University of Hawaii, Honolulu, HI, USA

Funding: US Department of Homeland Security DNDO ARI program GRANT NO. 2010-DN-077-ARI045-02
The Free-Electron Laser Laboratory at the University of Hawaii has constructed and tested a scanning wire beam position monitor to aid the alignment and optimization of a high spectral brightness inverse-Compton scattering X-ray source. X-rays are produced by colliding the 40 MeV electron beam from a pulsed S-band LINAC with infrared laser pulses from a mode-locked free-electron laser driven by the same electron beam. The electron and laser beams are focused to 60 micron diameters at the interaction point to achieve high scattering efficiency. This wire-scanner allows for high resolution measurements of the size and position of both the laser and electron beams at the interaction point to verify spatial coincidence. Time resolved measurements of secondary emission current allow us to monitor the transverse spatial evolution of the e-beam throughout the duration of a 4 microsecond macropulse while the laser is simultaneously profiled by pyrometer measurement of the occulted infrared beam. Using this apparatus we have demonstrated that the electron and laser beams can be co-aligned with a precision better than 10 microns as required to maximize X-ray yield.

Poster WEPF21 [14.675 MB]

WEPF22

Non Invasive Optical Synchrotron Radiation Monitor Using a Mini-Chicane

emittance, radiation, diagnostics, space-charge

860

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

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

Poster WEPF22 [0.642 MB]

WEPF24

Charge Monitors at the Relativistic Electron Gun for Atomic Exploration – REGAE

laser, diagnostics, DESY, gun

868

H. Delsim-Hashemi, K. Flöttmann, M. Seebach
DESY, Hamburg, Germany
S. Bayesteh
Uni HH, Hamburg, Germany

A new linac is commissioned at DESY mainly as the electron source for femtosecond electron diffraction facility REGAE (Relativistic Electron Gun for Atomic Exploration). REGAE comprises a photo-cathode gun followed by normal conducting 1.5 cell rf-cavity to provide sub pC charge electron-bunches of 2-5 MeV with a coherence length of 30nm. In order to produce and maintain such electron bunches, sophisticated single-shot diagnostics are desired e.g. emittance, energy, energy-spread and bunch-length measurement. There are three methods at REGAE for charge measurement. The most routine method is based on Faraday-cups that are distributed along machine and can provide charge reading down to ~50 fC. The second method, which is non-destructive, is a cavity based antenna that measures beam induced fields. A third method is based on beam-profile measurement diagnostics. By proper calibration of integral intensity that arrives at detector one can measure charges down to fC level. The last method has the potential to reach the limit of few electrons charge when state-of-the-art intensifiers are used in profile monitors.

WEPF27

Coherent Ultraviolet Radiation Measurements of Laser Induced Bunching in a Seeded FEL

radiation, laser, bunching, FEL

879

M. Veronese, A. Abrami, E. Allaria, M. Ferianis, E. Ferrari, M. Trovò
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
F. Cianciosi
ESRF, Grenoble, France

Optimization of the bunching process in a seeded FEL like FERMI@Elettra is an important aspect for machine operation. In this paper we discuss about the power detection of coherent radiation in the UV range as a valuable method for optimizing the bunching induced by the seeding process on the electron beam. Experimental results obtained at FERMI@Elettra are presented here. Measurements of UV coherent transition and diffraction radiation have been used to quantify the bunching produced by the seed laser at lower laser harmonics. The dependence of the laser induced CUVTR signal on various parameters is experimentally studied. Future upgrades and possibilities for bunching measurements at shortest wavelengths are also discussed.

WEPF34

Accurate Measurement of Small Electron Beam Currents at the MLS Electron Storage Ring

storage-ring, synchrotron, synchrotron-radiation, radiation

903

R. Klein, G. Brandt, D. Herzog, R. Thornagel
PTB, Berlin, Germany

The PTB, the German metrology institute, utilizes the electron storage ring MLS in Berlin Adlershof for the realization of the radiometric units in ultraviolet and vacuum ultraviolet spectral range. For this purpose the MLS can be operated as a primary source standard of calculable synchrotron radiation with very flexible parameters, especially in terms of electron beam energy and electron beam current. We report on improvements in the measurement of the electron beam current in the nA and pA range. In this range the electron beam current can be very accurately measured by counting the stored electrons.

WEPF36

X-ray Cherenkov Radiation as a Source for Relativistic Charged Particle Beam Diagnostics

radiation, polarization, photon, target

910

A.S. Konkov, A.S. Gogolev, A. Potylitsyn
TPU, Tomsk, Russia
P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom

Funding: The work was partially supported by Russian Ministry of Science and Education within the grant No. 14.B37.21.0912.
Recent progress in development of accelerator technology for future linear colliders and X-ray free electron lasers has generated an interest in developing novel diagnostics equipment with resolution surpassing the unique beam parameters. Cherenkov radiation (CR) in the X-ray region in the vicinity of the absorption edges is one of the promising sources for relativistic charged particle beam diagnostics. In this work we have demonstrated CR characteristics in the X-ray region significantly depend on the energy of the emitted photons, because the CR is only generated in the frequency region in the vicinity of the atomic absorption edges, where the well-known Cherenkov condition is work. This peculiarity can be explained by resonance behaviour of the permittivity in the frequency range. It will result in the fact that the CR will stand out of any other types of polarisation radiation both on intensity and shape of angular distribution giving a unique opportunity to apply this phenomenon for charged particle beam diagnostics.

Poster WEPF36 [42.675 MB]

THAL3

Charge Distribution Measurements at ALBA

photon, synchrotron, BPM, injection

925

L. Torino, U. Iriso
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

Two different set-ups are used to perform quantitative measurements of the charge distribution at ALBA. The first consists in a real-time analysis of data coming from the Fast Current Transformer or from the buttons of a Beam Position Monitor installed in the Storage Ring. The second is performed at the diagnostic visible beamline Xanadu, using a Photomultiplier that measures the temporal distribution of synchrotron light. In both cases a quantitative estimation of the charge distribution is obtained after a dedicated data treatment and beam current measurements from the DCCT. We compare results with both methods, and discuss differences and limitations with respect to bunch purity measurements with the Time Correlated Single Photon Counting technique.

Slides THAL3 [15.369 MB]