DIPAC2011 - List of Keywords (radiation)

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

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

MOPD30	Bunch Length Measurement for PETRA III Light Source Storage Ring	synchrotron, ion, extraction, vacuum	113
	H.-C. Schröder, A. Affeldt, H.P. Gausepohl, G. Kube, G. Priebe DESY, Hamburg, Germany
	To fulfill the demand for a very high brilliance synchrotron light source, it is required, that the individual particle bunches, used to create the synchrotron light in special undulator sections, do not exceed certain limits in linear dimension and divergence during the storage time. The bunch length measurement in the visible region of the spectrum is the sole system to measure the longitudinal beam parameter needed for a complete description of the behavior of the PETRAIII positron beam. A detailed description of the dipole magnet visible synchrotron light extraction, the light transport and the analysis by means of a Streak Camera System (SCS) in the context of the PETRAIII storage ring is given. The influence of the custom designed apochromatic refractive optics transport line on the time resolution of the bunch length measurement is discussed and values are given. The final time resolution of the whole system transport optics and Streak camera is shown to be not bigger than 4 ps. Several measurements from PETRAIII runs are presented and results of the bunch length measurements are shown. The typical bunch length measured is about 40 ps.
	Poster MOPD30 [6.402 MB]

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

MOPD32	Bunch Length Measurement from Power Fluctuation at Diamond	synchrotron, cavity, synchrotron-radiation, lattice	119
	C.A. Thomas, I.P.S. Martin, G. Rehm Diamond, Oxfordshire, United Kingdom
	Bunch length can be measured using the visible light power fluctuation statistics of an individual bunch. This method developed at ALS has been implemented at Diamond with further improvement on the detection method and the speed of the measurement. In this paper, we firstly report on the development and implementation of the method. We will show the performance of several detector diodes used and the limits of the method. Validation of the method will be demonstrated against streak camera measurement with picosecond long bunches. Before concluding, we will discuss about the strengths and weaknesses of the method.

MOPD37	Simulations of the Coherent Gap Radiation for the Bunch Length Monitor of FERMI@Elettra	simulation, vacuum, resonance, electromagnetic-fields	134
	R. Appio, P. Craievich, M. Ferianis, M. Veronese ELETTRA, Basovizza, Italy
	Non-destructive bunch length measurements after the magnetic compression is performed in Fermi@Elettra via the so-called Bunch Length Monitor (BLM) diagnostics. The BLM system is based on the diffraction radiation from a ceramic gap, captured by three millimeter-waves diodes, and the edge radiation from the last bending magnet of the bunch compressors, captured by a pyrodetector. In this paper we report on the study of the coherent radiation from a gap which we performed both applying the analytical theory and by means of simulations of the radiated electromagnetic field (CST Particle Studio). The study started from a simple gap in vacuum; time and frequency domain results were then investigated and compared with analytical theory. Finally in order to study a more realistic system, we investigated the effect of the dielectric and metallic holed shield used to assure the electric continuity.

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

MOPD41	A Fast CVD Diamond Beam Loss Monitor for LHC	collimation, controls, beam-losses, instrumentation	143
	E. Griesmayer, B. Dehning, D. Dobos, E. Effinger, H. Pernegger CERN, Geneva, Switzerland
	Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400 MHz RF frequency as well as the nominal bunch separation of 25 ns. In future, these detectors will be used to study ghost bunches and particles in the 3 μs abort gap.

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

MOPD53	Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI	ion, heavy-ion, target, background	170
	P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne GSI, Darmstadt, Germany W. Ensinger, K. Renuka TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026 Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.
	Poster MOPD53 [1.897 MB]

MOPD55	SEM-GRID Prototype Electronics using Charge-Frequency-Converters	diagnostics, controls, ion, monitoring	176
	M. Witthaus, J. Adamczewski-Musch, H. Flemming, J. Frühauf, S. Löchner, H. Reeg, P. Skott GSI, Darmstadt, Germany
	A prototype system using an ASIC equipped with 8 Charge-to-Frequency Converters (CFC) was developed in collaboration between the Beam Diagnostics and Experiment Electronics Department at GSI. The maximum sensitivity is 250 fC per output pulse. It will serve as an economic alternative for the readout electronics of Secondary Electron Monitor (SEM)profile grids or comparable beam diagnostic devices like Multi-Wire Proportional Chambers (MWPC). The goal of this contribution is to report on a detailed performance test under real beam conditions at GSI beam lines. A 32-channel electronics is connected to different beam profile SEM-grids at a LINAC beam line and tested with various beam conditions. Transversal beam profiles with a time resolution down to the microsecond range have been recorded successfully. Beam profiles recorded with the new CFC-board and the old standard trans-impedance amplifiers agreed well. Further measurements were done with Multi-Wire Proportional Chamber. Therefore the prototype was extended to 64-input channels recently.
	Poster MOPD55 [1.344 MB]

MOPD59	A New Fast Acquisition Profile for the LHC and the SPS	optics, betatron, injection, alignment	182
	S. Burger, A. Boccardi, E. Bravin, A. Rabiller, R.S. Sautier CERN, Geneva, Switzerland
	The beam profile is an important parameter for the tuning of particle accelerators. These profiles are often obtained by imaging optical transition radiation from a radiator on a CCD camera. This technique works well for slow acquisitions, but in some cases it is necessary to acquire profiles with higher rates where such standard cameras are no longer suitable. In our case the aim is to sample the profiles on a turn-by-turn basis which, for the CERN-SPS, corresponds to ~44 kHz. For this reason we have developed a fast detector based on a recent Hamamatsu linear CCD and an optical system using cylindrical lenses. The readout electronics is based on CERN developed, radiation tolerant components and the digital data is transmitted to an acquisition board outside of the tunnel by mean of optical fibres. This contribution describes the system and shows the performance obtained on a test bench.

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

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

MOPD83	Performance of the Fast Beam Conditions Monitor BCM1F in the CMS Experiment at the LHC	proton, monitoring, luminosity, vacuum	239
	M.E. Castro Carballo DESY Zeuthen, Zeuthen, Germany
	In the CMS detector a series of beam condition monitors were installed and are in operation for measuring radiation doses and preventing possible damages to the detector in case of beam losses. The Fast Beam Condition Monitor, BCM1F, is installed inside the pixel volume close to the beam pipe and it consists of two planes of 4 modules each located 1.8 m away from the IP, on both sides. It uses single-crystal CVD diamond sensors and radiation hard front-end electronics, along with an optical transmission of the signal. It was designed for fast flux monitoring, measuring beam halo and collision products on a bunch by bunch basis. Early in November 2009 the LHC restarted running with beams and since then BCM1F has been recording data from beam halo, beam studies, proton-proton and lead-lead collisions. It is an invaluable tool in everyday CMS operation and, due to the high sensitivity to beam conditions, is providing the so called Background (BKGD) 1 to LHC operators. A characterization of the system on the basis of data collected during LHC operation will be presented.
	Poster MOPD83 [1.449 MB]

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

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

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

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

TUPD39	Observation of Synchrotron Radiation Using Low Noise Block (LNB) at ANKA	synchrotron, storage-ring, synchrotron-radiation, vacuum	389
	V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale KIT, Karlsruhe, Germany F. Caspers CERN, Geneva, Switzerland
	Funding: Work supported by the Initiative and Networking Fund of the Helmholtz Association under contact number VH-NG-320 Generally Coherent Synchrotron Radiation (CSR) is emitted for wavelengths longer than or equal the bunch length, so for CSR in the THz-range short bunches are required. There are two types of detectors in this range of the spectrum: slow detectors like a golay cell or pyrometric detectors (used for e.g. imaging, spectroscopy) and fast detectors like superconducting bolometer detector systems and Schottky Barrier diodes (used for e.g. the investigation of dynamic processes in accelerator physics). The hot electron bolometer (HEB) detector system is a member of second group. It is very fast and has broad spectral characteristics, but unfortunately very expensive and have to be cooled using liquid helium. If the broad spectral response is not important, it will be suitably to use a Schottky Barrier diode instead. These detectors are massively cheaper but also slower. As an alternative to a Schottky diode a LNB (Low Noise Block) can be also used. It is usually used in standard TV-SAT-receivers. Due to mass production LNBs became very cheap, moreover they are optimized to detect very low intensity "noise-like" signals. In this paper we present our experience with a LNB at ANKA.

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

TUPD42	Design and Experiences with the Beam Condition Monitor as Protection System in the CMS Experiment of the LHC	background, vacuum, monitoring, beam-losses	398
	M. Guthoff CERN, Geneva, Switzerland
	The Beam Condition Monitor (BCM) is used as protection system. In order to prevent damage to the pixel and tracker detectors it can trigger a beam dump when extremely high beam losses occur. The system consists of BCM1L with 4 diamonds per side at 1.8m away from the interaction point and BCM2 with 4 inner and 8 outer diamonds per side at 14.4m away from the interaction point. As detector material poly-crystalline CVD diamonds are used. The readout electronics is identical to the Beam Loss Monitor (BLM) system of the LHC. With cross calibration measurements a direct comparison between the BLM and the BCM systems is possible. The BCM system is therefore a transparent extension of the BLM system into the CMS cavern. The BCM2 system has been active in the beam abort system since the beginning of collisions at the LHC. Design and performance of the system during the run of the LHC so far will be presented. *on behalf of the CMS BRM group.
	Poster TUPD42 [0.736 MB]

TUPD46	Beam Species Fraction Measurement using Doppler Shift Method with FUJIKURA Fiberscope for IFMIF-EVEDA Injector	proton, diagnostics, target, neutron	407
	F. Senée, B. Pottin CEA/DSM/IRFU, France G. Adroit, R. Gobin, O. Tuske CEA/IRFU, Gif-sur-Yvette, France A. Olivier IPN, Orsay, France
	To characterize high intensity ion beam in low energy beam transport line, diagnostics based on residual gas molecule excitation are commonly used. An example is CCD sensors for beam intensity, beam position and beam profile measurements. At CEA/Saclay with the SILHI injector, beam images transports from viewport to sensor have been performed with a fiberscope. Such technique will be used to transport the beam images away from the irradiated zone of the IFMIF-EVEDA tunnel which requires using hardened radiation devices. Indeed, the (D,d) reaction, due to interaction of 140 mA-100 keV deuteron beam with vacuum pipes or scrapers, leads to high neutron and gamma ray flux. As a consequence, in addition to CID cameras for online beam positioning and shape measurements, a 20 m long Fujikura fiberscope has been selected to analyze species fraction using the Doppler shift method. Preliminary measurements have been performed with the SILHI beam to characterize the fiberscope. Its spatial resolution and transmission as well as a CCD sensor and fiberscope comparison are presented. Beam species fractions with and without the use of fiberscope will be also reported.

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

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

TUPD83	Photodiode Calibration using an Electrical Substitution Radiometer in the Hard X-ray Region	simulation, photon, alignment, cryogenics	500
	N.I. Bolibruch, R. Igarashi, J.M. Vogt CLS, Saskatoon, Saskatchewan, Canada
	Funding: Work supported by NSERC, NRC, CIHR, WEDC. An electrical substitution radiometer under development at the Canadian Light Source (CLS) has been used to calibrate a photodiode (AXUV100) from International Radiation Detectors Inc. within an energy range of 8 keV to 30 keV. These measurements were made using monochromatic X-rays on the Biomedical Imaging and Therapy bend magnet beam line and the Hard X-Ray Microanalysis beam line at the CLS. The results were then compared with silicon absorption calculations using data from the NIST mass absorption coefficient tables. Good agreement has been found between the diode calibration obtained from the radiometer and the theoretical calculation of the diode response.

TUPD90	POMPOMs: Cost-Efficient Polarity Sensors for the MICE Muon Beamline	EPICS, monitoring, dipole, controls	518
	J.J. Nebrensky Brunel University, Middlesex, United Kingdom P.M. Hanlet IIT, Chicago, Illinois, USA
	Funding: STFC (UK) The cooling effect in MICE (Muon Ionisation Cooling Experiment) will be studied with both positive and negative muons, reversing the electrical input to the magnets by physically swapping over the power leads. Ensuring the actual operating polarity of the beamline is correctly recorded is a manual step and at risk of error or omission. We have deployed a simple system for monitoring the operating polarity of the two bending magnets by placing in each dipole bore a Honeywell LOHET-II Hall-effect sensor that operates past saturation at nominal field strengths, and thus return one of two well-defined voltages corresponding to the two possible polarities of the magnet. The environment in the experimental hall is monitored by an AKCP securityProbe 5E system integrated into our EPICS-based controls and monitoring system. We read out the beamline polarity sensors using a voltmeter module, and translate the output voltage into a polarity (or alarm) state within EPICS whence it can be accessed by the operators and stored in the output datastream. Initial test of the LOHET-II sensors indicates they will still be able to indicate beamline polarity after radiation doses of 600 Gy (Co60). We'd like to thank Prof. Peter Hobson and Dr David Smith at Brunel University for performing the sensor irradiation
	Poster TUPD90 [0.627 MB]

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

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

Paper

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MOOB03

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

wakefield, simulation, electron, vacuum

12

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

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

Slides MOOB03 [1.353 MB]

MOPD09

Electron Beam Diagnostics for FLASH II

diagnostics, undulator, electron, laser

53

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

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

MOPD30

Bunch Length Measurement for PETRA III Light Source Storage Ring

synchrotron, ion, extraction, vacuum

113

H.-C. Schröder, A. Affeldt, H.P. Gausepohl, G. Kube, G. Priebe
DESY, Hamburg, Germany

To fulfill the demand for a very high brilliance synchrotron light source, it is required, that the individual particle bunches, used to create the synchrotron light in special undulator sections, do not exceed certain limits in linear dimension and divergence during the storage time. The bunch length measurement in the visible region of the spectrum is the sole system to measure the longitudinal beam parameter needed for a complete description of the behavior of the PETRAIII positron beam. A detailed description of the dipole magnet visible synchrotron light extraction, the light transport and the analysis by means of a Streak Camera System (SCS) in the context of the PETRAIII storage ring is given. The influence of the custom designed apochromatic refractive optics transport line on the time resolution of the bunch length measurement is discussed and values are given. The final time resolution of the whole system transport optics and Streak camera is shown to be not bigger than 4 ps. Several measurements from PETRAIII runs are presented and results of the bunch length measurements are shown. The typical bunch length measured is about 40 ps.

Poster MOPD30 [6.402 MB]

MOPD31

Future Timing and Synchronization Scheme at ELBE

laser, electron, gun, controls

116

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

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

MOPD32

Bunch Length Measurement from Power Fluctuation at Diamond

synchrotron, cavity, synchrotron-radiation, lattice

119

C.A. Thomas, I.P.S. Martin, G. Rehm
Diamond, Oxfordshire, United Kingdom

Bunch length can be measured using the visible light power fluctuation statistics of an individual bunch. This method developed at ALS has been implemented at Diamond with further improvement on the detection method and the speed of the measurement. In this paper, we firstly report on the development and implementation of the method. We will show the performance of several detector diodes used and the limits of the method. Validation of the method will be demonstrated against streak camera measurement with picosecond long bunches. Before concluding, we will discuss about the strengths and weaknesses of the method.

MOPD37

Simulations of the Coherent Gap Radiation for the Bunch Length Monitor of FERMI@Elettra

simulation, vacuum, resonance, electromagnetic-fields

134

R. Appio, P. Craievich, M. Ferianis, M. Veronese
ELETTRA, Basovizza, Italy

Non-destructive bunch length measurements after the magnetic compression is performed in Fermi@Elettra via the so-called Bunch Length Monitor (BLM) diagnostics. The BLM system is based on the diffraction radiation from a ceramic gap, captured by three millimeter-waves diodes, and the edge radiation from the last bending magnet of the bunch compressors, captured by a pyrodetector. In this paper we report on the study of the coherent radiation from a gap which we performed both applying the analytical theory and by means of simulations of the radiated electromagnetic field (CST Particle Studio). The study started from a simple gap in vacuum; time and frequency domain results were then investigated and compared with analytical theory. Finally in order to study a more realistic system, we investigated the effect of the dielectric and metallic holed shield used to assure the electric continuity.

MOPD38

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

laser, electron, feedback, diagnostics

137

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

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

Poster MOPD38 [3.262 MB]

MOPD41

A Fast CVD Diamond Beam Loss Monitor for LHC

collimation, controls, beam-losses, instrumentation

143

E. Griesmayer, B. Dehning, D. Dobos, E. Effinger, H. Pernegger
CERN, Geneva, Switzerland

Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400 MHz RF frequency as well as the nominal bunch separation of 25 ns. In future, these detectors will be used to study ghost bunches and particles in the 3 μs abort gap.

MOPD49

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

linac, emittance, ion, proton

161

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

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

MOPD53

Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI

ion, heavy-ion, target, background

170

P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne
GSI, Darmstadt, Germany
W. Ensinger, K. Renuka
TU Darmstadt, Darmstadt, Germany

Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026
Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.

Poster MOPD53 [1.897 MB]

MOPD55

SEM-GRID Prototype Electronics using Charge-Frequency-Converters

diagnostics, controls, ion, monitoring

176

M. Witthaus, J. Adamczewski-Musch, H. Flemming, J. Frühauf, S. Löchner, H. Reeg, P. Skott
GSI, Darmstadt, Germany

A prototype system using an ASIC equipped with 8 Charge-to-Frequency Converters (CFC) was developed in collaboration between the Beam Diagnostics and Experiment Electronics Department at GSI. The maximum sensitivity is 250 fC per output pulse. It will serve as an economic alternative for the readout electronics of Secondary Electron Monitor (SEM)profile grids or comparable beam diagnostic devices like Multi-Wire Proportional Chambers (MWPC). The goal of this contribution is to report on a detailed performance test under real beam conditions at GSI beam lines. A 32-channel electronics is connected to different beam profile SEM-grids at a LINAC beam line and tested with various beam conditions. Transversal beam profiles with a time resolution down to the microsecond range have been recorded successfully. Beam profiles recorded with the new CFC-board and the old standard trans-impedance amplifiers agreed well. Further measurements were done with Multi-Wire Proportional Chamber. Therefore the prototype was extended to 64-input channels recently.

Poster MOPD55 [1.344 MB]

MOPD59

A New Fast Acquisition Profile for the LHC and the SPS

optics, betatron, injection, alignment

182

S. Burger, A. Boccardi, E. Bravin, A. Rabiller, R.S. Sautier
CERN, Geneva, Switzerland

The beam profile is an important parameter for the tuning of particle accelerators. These profiles are often obtained by imaging optical transition radiation from a radiator on a CCD camera. This technique works well for slow acquisitions, but in some cases it is necessary to acquire profiles with higher rates where such standard cameras are no longer suitable. In our case the aim is to sample the profiles on a turn-by-turn basis which, for the CERN-SPS, corresponds to ~44 kHz. For this reason we have developed a fast detector based on a recent Hamamatsu linear CCD and an optical system using cylindrical lenses. The readout electronics is based on CERN developed, radiation tolerant components and the digital data is transmitted to an acquisition board outside of the tunnel by mean of optical fibres. This contribution describes the system and shows the performance obtained on a test bench.

MOPD61

Vertical Emittance Measurement at the ESRF

emittance, photon, synchrotron, dipole

188

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

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

MOPD62

Storage Ring Injector Diagnostics using Synchrotron Radiation

injection, emittance, diagnostics, booster

191

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

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

Poster MOPD62 [0.451 MB]

MOPD83

Performance of the Fast Beam Conditions Monitor BCM1F in the CMS Experiment at the LHC

proton, monitoring, luminosity, vacuum

239

M.E. Castro Carballo
DESY Zeuthen, Zeuthen, Germany

In the CMS detector a series of beam condition monitors were installed and are in operation for measuring radiation doses and preventing possible damages to the detector in case of beam losses. The Fast Beam Condition Monitor, BCM1F, is installed inside the pixel volume close to the beam pipe and it consists of two planes of 4 modules each located 1.8 m away from the IP, on both sides. It uses single-crystal CVD diamond sensors and radiation hard front-end electronics, along with an optical transmission of the signal. It was designed for fast flux monitoring, measuring beam halo and collision products on a bunch by bunch basis. Early in November 2009 the LHC restarted running with beams and since then BCM1F has been recording data from beam halo, beam studies, proton-proton and lead-lead collisions. It is an invaluable tool in everyday CMS operation and, due to the high sensitivity to beam conditions, is providing the so called Background (BKGD) 1 to LHC operators. A characterization of the system on the basis of data collected during LHC operation will be presented.

Poster MOPD83 [1.449 MB]

TUOA04

Instrumentation for Machine Protection at FERMI@Elettra

undulator, FEL, diagnostics, electron

286

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

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

Slides TUOA04 [2.559 MB]

TUPD32

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

electron, vacuum, simulation, FEL

374

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

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

TUPD33

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

diagnostics, electron, vacuum, synchrotron

377

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

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

TUPD38

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

electron, simulation, diagnostics, optics

386

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

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

TUPD39

Observation of Synchrotron Radiation Using Low Noise Block (LNB) at ANKA

synchrotron, storage-ring, synchrotron-radiation, vacuum

389

V. Judin, N. Hiller, A. Hofmann, E. Huttel, B. Kehrer, M. Klein, S. Marsching, A.-S. Müller, N.J. Smale
KIT, Karlsruhe, Germany
F. Caspers
CERN, Geneva, Switzerland

Funding: Work supported by the Initiative and Networking Fund of the Helmholtz Association under contact number VH-NG-320
Generally Coherent Synchrotron Radiation (CSR) is emitted for wavelengths longer than or equal the bunch length, so for CSR in the THz-range short bunches are required. There are two types of detectors in this range of the spectrum: slow detectors like a golay cell or pyrometric detectors (used for e.g. imaging, spectroscopy) and fast detectors like superconducting bolometer detector systems and Schottky Barrier diodes (used for e.g. the investigation of dynamic processes in accelerator physics). The hot electron bolometer (HEB) detector system is a member of second group. It is very fast and has broad spectral characteristics, but unfortunately very expensive and have to be cooled using liquid helium. If the broad spectral response is not important, it will be suitably to use a Schottky Barrier diode instead. These detectors are massively cheaper but also slower. As an alternative to a Schottky diode a LNB (Low Noise Block) can be also used. It is usually used in standard TV-SAT-receivers. Due to mass production LNBs became very cheap, moreover they are optimized to detect very low intensity "noise-like" signals. In this paper we present our experience with a LNB at ANKA.

TUPD41

The Beam Halo Monitor for FLASH

diagnostics, electron, laser, free-electron-laser

395

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

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

TUPD42

Design and Experiences with the Beam Condition Monitor as Protection System in the CMS Experiment of the LHC

background, vacuum, monitoring, beam-losses

398

M. Guthoff
CERN, Geneva, Switzerland

The Beam Condition Monitor (BCM) is used as protection system. In order to prevent damage to the pixel and tracker detectors it can trigger a beam dump when extremely high beam losses occur. The system consists of BCM1L with 4 diamonds per side at 1.8m away from the interaction point and BCM2 with 4 inner and 8 outer diamonds per side at 14.4m away from the interaction point. As detector material poly-crystalline CVD diamonds are used. The readout electronics is identical to the Beam Loss Monitor (BLM) system of the LHC. With cross calibration measurements a direct comparison between the BLM and the BCM systems is possible. The BCM system is therefore a transparent extension of the BLM system into the CMS cavern. The BCM2 system has been active in the beam abort system since the beginning of collisions at the LHC. Design and performance of the system during the run of the LHC so far will be presented.
*on behalf of the CMS BRM group.

Poster TUPD42 [0.736 MB]

TUPD46

Beam Species Fraction Measurement using Doppler Shift Method with FUJIKURA Fiberscope for IFMIF-EVEDA Injector

proton, diagnostics, target, neutron

407

F. Senée, B. Pottin
CEA/DSM/IRFU, France
G. Adroit, R. Gobin, O. Tuske
CEA/IRFU, Gif-sur-Yvette, France
A. Olivier
IPN, Orsay, France

To characterize high intensity ion beam in low energy beam transport line, diagnostics based on residual gas molecule excitation are commonly used. An example is CCD sensors for beam intensity, beam position and beam profile measurements. At CEA/Saclay with the SILHI injector, beam images transports from viewport to sensor have been performed with a fiberscope. Such technique will be used to transport the beam images away from the irradiated zone of the IFMIF-EVEDA tunnel which requires using hardened radiation devices. Indeed, the (D,d) reaction, due to interaction of 140 mA-100 keV deuteron beam with vacuum pipes or scrapers, leads to high neutron and gamma ray flux. As a consequence, in addition to CID cameras for online beam positioning and shape measurements, a 20 m long Fujikura fiberscope has been selected to analyze species fraction using the Doppler shift method. Preliminary measurements have been performed with the SILHI beam to characterize the fiberscope. Its spatial resolution and transmission as well as a CCD sensor and fiberscope comparison are presented. Beam species fractions with and without the use of fiberscope will be also reported.

TUPD48

Transition Radiation from a Cylindrical Target and Transverse Beam Size Diagnostics

target, electron, optics, FEL

410

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

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

TUPD54

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

electron, cathode, laser, FEL

428

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

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

Poster TUPD54 [0.193 MB]

TUPD83

Photodiode Calibration using an Electrical Substitution Radiometer in the Hard X-ray Region

simulation, photon, alignment, cryogenics

500

N.I. Bolibruch, R. Igarashi, J.M. Vogt
CLS, Saskatoon, Saskatchewan, Canada

Funding: Work supported by NSERC, NRC, CIHR, WEDC.
An electrical substitution radiometer under development at the Canadian Light Source (CLS) has been used to calibrate a photodiode (AXUV100) from International Radiation Detectors Inc. within an energy range of 8 keV to 30 keV. These measurements were made using monochromatic X-rays on the Biomedical Imaging and Therapy bend magnet beam line and the Hard X-Ray Microanalysis beam line at the CLS. The results were then compared with silicon absorption calculations using data from the NIST mass absorption coefficient tables. Good agreement has been found between the diode calibration obtained from the radiometer and the theoretical calculation of the diode response.

TUPD90

POMPOMs: Cost-Efficient Polarity Sensors for the MICE Muon Beamline

EPICS, monitoring, dipole, controls

518

J.J. Nebrensky
Brunel University, Middlesex, United Kingdom
P.M. Hanlet
IIT, Chicago, Illinois, USA

Funding: STFC (UK)
The cooling effect in MICE (Muon Ionisation Cooling Experiment) will be studied with both positive and negative muons, reversing the electrical input to the magnets by physically swapping over the power leads. Ensuring the actual operating polarity of the beamline is correctly recorded is a manual step and at risk of error or omission. We have deployed a simple system for monitoring the operating polarity of the two bending magnets by placing in each dipole bore a Honeywell LOHET-II Hall-effect sensor that operates past saturation at nominal field strengths, and thus return one of two well-defined voltages corresponding to the two possible polarities of the magnet. The environment in the experimental hall is monitored by an AKCP securityProbe 5E system integrated into our EPICS-based controls and monitoring system. We read out the beamline polarity sensors using a voltmeter module, and translate the output voltage into a polarity (or alarm) state within EPICS whence it can be accessed by the operators and stored in the output datastream. Initial test of the LOHET-II sensors indicates they will still be able to indicate beamline polarity after radiation doses of 600 Gy (Co60).
We'd like to thank Prof. Peter Hobson and Dr David Smith at Brunel University for performing the sensor irradiation

Poster TUPD90 [0.627 MB]

WEOA01

Summary of COTR Effects

FEL, emittance, diagnostics, electron

539

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

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

Slides WEOA01 [2.520 MB]

WEOA02

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

target, diagnostics, electron, FEL

544

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

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

Slides WEOA02 [6.967 MB]