DIPAC2011 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOOB04	Bunch Compression, RF Curvature Correction and R₅₅, T₅₅₅ and U₅₅₅₅ Measurements at JLab FEL	FEL, cavity, SRF, sextupole	15
	P. Evtushenko, S.V. Benson, D. Douglas JLAB, Newport News, Virginia, USA
	The JLab IR/UV FEL Upgrade operates with the bunch length compressed down to 100-150 fs RMS. An indispensible part of the bunch compression scheme is the correction of the so-called LINAC RF curvature. Unlike other systems – where the RF curvature gets corrected using higher a harmonic LINAC – our system utilizes magnetic elements of the beam transport system to correct and adjust the second and third order correlation terms. These are expressed in terms of the transport matrix elements T₅₆₆ and U₅₆₆₆. The linear correlation term described by M₅₅ is adjusted using the magnetic system as well. The large energy spread induced on the beam by the FEL operation is compressed as a part of the energy recovery process. As in the case of bunch length compression, this energy compression is optimized by properly adjusting high order transport matrix elements. In this contribution we describe the system used for direct measurements of the transport matrix elements M₅₅, T₅₆₆ and U₅₆₆₆ and its impact on the operation and bunch compression. Results of the measurements are presented together with the bunch length measurements including the data showing resolution and accuracy of the system.
	Slides MOOB04 [0.999 MB]

MOOC01	Overview of Recent Trends and Developments for BPM Systems	cavity, pick-up, coupling, monitoring	18
	M. Wendt Fermilab, Batavia, USA
	Beam position monitoring (BPM) systems are the workhorse beam diagnostics for almost any kind of charged particle accelerator; linear, circular or transport-lines, operating with leptons, hadrons or heavy ions. The BPMs are essential for beam commissioning, accelerator fault analysis and trouble shooting, machine optics and lattice measurements, and finally for the accelerator optimization to achieve the ultimate beam quality. This presentation summarizes the efforts of the beam instrumentation community on recent developments and advances on BPM technologies, i.e. BPM pickup monitors and front-end electronics (analog and digital). Principles, examples, and state-of-the-art status on various BPM techniques are outlined, serving hadron and heavy ion machines, sync light synchrotron's, as well as electron linacs for FEL or HEP applications.
	Slides MOOC01 [4.123 MB]

MOPD07	Newly Installed Beam Diagnostics at the Australian Synchrotron	injection, booster, synchrotron, diagnostics	47
	E.D. van Garderen, M.J. Boland, G. LeBlanc, B. Mountford, A. Rhyder, A. C. Starritt, A. Walsh, K. Zingre ASCo, Clayton, Victoria, Australia
	The Australian Synchrotron (AS) is aiming at implementing Top-Up operations in 2012. To reduce costs only one of the two klystrons in the linac will be used. The electron beam in the linac will only be accelerated to 80 MeV, instead of 100 MeV achieved currently. The injection system will need to be recommissioned. The beam position monitors in the booster have been upgraded and YAG:Ce screens have been added to the booster-to-storage ring (BTS) transfer line. In addition the injection efficiency will be optimized and monitored. For this purpose another Fast Current Transformer has also been installed at the end of the BTS.

MOPD08	Beam Diagnostics in the J-PARC Linac for ACS Upgrade	diagnostics, pick-up, acceleration, simulation	50
	A. Miura, S. Sato JAEA/J-PARC, Tokai-mura, Japan Z. Igarashi, M. Ikegami, T. Miyao, T. Toyama KEK, Ibaraki, Japan T. Tomisawa JAEA/LINAC, Ibaraki-ken, Japan
	J-PARC had developed the beam diagnostic devices for the current J-PARC linac and has used them since the operation start. J-PARC linac began the energy upgrade project since 2009 and 21 ACS cavities will be installed. In this project, many cavities and related devices are newly installed in the ACS section and its downstream part. Because the beam parameters are updated, new beam diagnostic devices are fabricated and current diagnostic devices are developed. Beam position monitors (BPM) are newly designed and fabricated, based on the computer simulation and bench test. Because the gas proportional BLMs as the current BLM are sensitive to background noise of X-ray emitted from RF cavities, it is difficult to recognize real beam loss. We need to subtract an X-ray noise from the signal from BLM, another candidate BLMs have been tried to measure the beam loss. In addition, the bunch shape monitor for the longitudinal tuning has been developed in the corroboration with the institute for nuclear research, Russia. In this paper, we describe the new developed devices and their development process, especially for beam loss monitor and the developing bunch shape monitor.

MOPD19	Button BPM Development for the European XFEL	simulation, vacuum, cryogenics, cavity	83
	D. Lipka, B. Lorbeer, D. Nölle, M. Siemens, S. Vilcins DESY, Hamburg, Germany
	Button beam position monitors will be the main BPM type used to measure the electron beam position at the European XFEL. Two different kinds of buttons are necessary: one type will be installed in the acceleration modules of the cold linac and the other in the warm environment. The electro-magnetic design of the feedthrough for both types of buttons will be discussed. A comparison of the designed and measured RF properties will be presented. In addition to the usual RF properties, also the properties at cryogenic level will play a role. HOM power must not heat up the BPM feedthroughs, in order to keep the cryo load of an overall accelerator module low, and also to prevent damage due to large temperature gradients over the ceramics of the feedthrough. First measurements with beam at FLASH show good agreement of the measured signals with the expectation.

MOPD21	Overview of the BPM System of the ESS-Bilbao	controls, EPICS, LLRF, impedance	89
	D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo ESS-Bilbao, Zamudio, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain N. Garmendia, L. Muguira ESS Bilbao, Bilbao, Spain
	The BPM system from ESS-Bilbao is presented, including test bench, electronics and test results. Our test bench implements 4 capacitive buttons welded to the beam pipe. The position of the internal tube simulating the beam can be changed with respect to the outer tube within a range of 20 mm, with a resolution less than 10 μm. It is connected to an Analog Front-End (AFE) where signals are conditioned and converted to baseband and a Digital Unit (DU) to sample them and calculate the position and phase. The AFE is based on logarithmic amplifiers and IQ demodulators. Signals are converted from differential to single-ended and conditioned to meet the DU requirements (FPGA and ADC). DU includes offset compensation, gain adjustment, CORDIC, delta over σ algorithm and linearization blocks. To manage the FPGA a Java interface has been developed including also the EPICS integration by means of JavaIOC and a MySQL interface. The resolution and accuracy results are promising (less than 10 μm and 1° for the position and phase) provided that the effect of several errors such as temperature variations and nonlinearities are minimized through temperature regulation and system calibration.
	Poster MOPD21 [1.476 MB]

MOPD35	Improved Signal Treatment for Capacitive Linac Pick-Ups	pick-up, DTL, rfq, radio-frequency	128
	A. Reiter, C.M. Kleffner, B. Schlitt GSI, Darmstadt, Germany
	Phase probes are a crucial diagnostic tool for pulsed particle beams of linear accelerators. In this contribution we present a simple, but very effective analysis procedure which has been established in various applications during commissioning campaigns of injector linacs for medical facilities. These injectors consist of a 400 keV/u radio-frequency quadrupole followed by a 7 MeV/u inter-digital drift tube linac, both operating at 216.8 MHz. At GSI, the new analysis was recently applied at the HITRAP decelerator, also with promising results. The data analysis exploits the periodic nature of sampling process and bunch signal improving the detector sensitivity and achieving an effective resolution of < 10 ps. If the macro-pulse is sufficiently long, the quality of the data can be improved further by a statistical average of subsequent data blocks acquired within one single macro-pulse. The latter is important for experiments with low beam intensity and low repetition rate like HITRAP where averaging over many macro-pulses is cumbersome.

MOPD36	Development of a Silicon Detector Monitor for the Superconducting Upgrade of the REX-ISOLDE Heavy-Ion Linac at CERN	cavity, ion, diagnostics, rfq	131
	F. Zocca IEM, Madrid, Spain E. Bravin, M.A. Fraser, D. Voulot, F.J.C. Wenander, F. Zocca CERN, Geneva, Switzerland M. Pasini Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium
	A silicon detector monitor has been developed and tested in the frame of the beam diagnostics development program for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac at CERN. The monitor is intended for beam energy and timing measurements as well as for phase scanning of the superconducting cavities. Tests have been performed with a stable ion beam, composed of carbon, oxygen and neon ions accelerated to energies from 300 keV/u to 2.85 MeV/u. The silicon detector was placed directly in the beam line and tested with a beam which was strongly attenuated to simulate the single particle detection regime for which the monitor is intended to finally function. The energy measurements performed allowed for beam spectroscopy and ion identification with a resolution of 3%. The principle of cavity phase scanning was also demonstrated with the REX 7-gap resonator thanks to the accurate peak energy identification. The time structure of the beam, characterized by a bunch period of 9.87 ns, was measured with a resolution better than 200 ps. This paper describes the results from all these tests as well as providing details of the detector.

MOPD42	μ-loss Detector for IFMIF-EVEDA	neutron, solenoid, cryomodule, focusing	146
	J. Marroncle, P. Abbon, J. Egberts CEA/DSM/IRFU, France M. Pomorski CEA/DRT/LIST, Gif-sur-Yvette Cedex, France
	For the IFMIF-EVEDA project, a prototype accelerator is being built in Europe and installed at Rokkasho (Japan). It is designed to accelerate 125 mA CW Deuteron to 9 MeV. The very high space charge and high power (1.125 MW) of the beam make this accelerator very challenging. For hands-on maintenance requirements, losses must be well less than 1W/m, i.e. 10^-6 of the beam. That is why, in the 5-9 MeV superconducting Linac, beam dynamics physicists search to tune the beam by minimizing the very external part of the halo. The need is thus to be able to measure very tiny beam losses, called μ-losses, at all the focusing magnets. Only neutrons and γ exit from the beam pipe due to the low deuteron beam energy. Thus such beam loss detectors have to be sensitive to neutrons, but rather insensitive for X-rays and γ to decrease their contributions coming from super-conducting cavity emission. They must be radiation hardness qualified, and capable to work at cryogenic temperature. Single CVD diamonds (4×4×0.5 mm³) are studied for these purposes and first results seem to fulfill the requirements up to now.

MOPD43	Beam Loss Detected by Scintillation Monitor	hadron, background, simulation, quadrupole	149
	A. Miura, T. Maruta JAEA/J-PARC, Tokai-mura, Japan K. Hasegawa, N. Ouchi, H. Sako JAEA, Ibaraki-ken, Japan Z. Igarashi, M. Ikegami, T. Miyao KEK, Ibaraki, Japan
	Ar gas proportional BLMs have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. We have tried to measure the beam loss using scintillation monitors which would bring more accurate beam loss measurements with suppression of X-ray noise. We measured beam loss using scintillation beam loss monitors. Because this scintillation BLM is sensitive for low energy gamma-rays and fast neutrons, small signals from X-rays would be also detected. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. And many single events are observed in the intermediate pulse bunch with about 600 ns as pulse width. After all signals passed through the filter circuit and integrated circuit, total amount of X-ray noise can become smaller. We obtained the good performances of scintillation BLM with small effect of X-ray noise. This monitor can be used for beam loss measurement and a knob for tuning. Furthermore, because the detail structure can be detected, this monitor could be employed for another diagnostic device.

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

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

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

MOPD66	Upgrade of the CERN PSB/CPS Fast Intensity Measurements	synchrotron, proton, booster, status	200
	A. Monera Martinez, M. Andersen, D. Belohrad, L.K. Jensen, L. Søby CERN, Geneva, Switzerland G. Kasprowicz CREOTECH Ltd., Warsaw, Poland
	The CERN Proton Synchrotron Booster (PSB) and Proton Synchrotron (CPS) complex fast intensity measurement is undergoing a major upgrade. The old analogue electronics no longer provides enough accuracy, resolution and versatility to perform accurate beam intensity measurements. It has also become less reliable due to the ageing equipment. A new measurement system - Transformer Integrator Card (TRIC) - replaces these obsolete acquisition systems. TRIC is a generic platform used to measure the intensity in different transfer lines at CERN. Five TRICs were installed during the year 2010 in order to evaluate their performance with different beam types, from the low intensity pilot (5×10⁹ charges per bunch) to high intensity beams (1×10¹³ charges per bunch). The aim of this article is to present the technical aspects of the new system and the different measurement scenarios. It discusses possible sources of measurement errors and presents some statistical data acquired during this period.

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

MOPD97	Beam Position Monitor System for the CERN Linac4	pick-up, simulation, DTL, resonance	272
	J. Tan, L. Søby, M. Sordet CERN, Geneva, Switzerland
	The new LINAC4 will provide 160 MeV H¯ ion beams for charge-exchange and proton injection into the CERN accelerator complex. Among a wide variety of beam diagnostics devices, shorted stripline pick-ups will measure the absolute beam position, the relative and absolute beam current, and the average beam energy via the time-of-flight between two monitors. This paper describes the beam position monitor (BPM) with its electronic acquisition chain to be implemented on the movable test bench for beam characterization up to 12 MeV.

TUOA01	Beam Instrumentation in J-PARC	feedback, impedance, proton, septum	275
	T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The talk will summarize the beam instrumentation at J-PARC with a focus on MW class proton beams. The measurements of beam intensities, positions, losses, profiles, and halos at each stage of accelerator, 181 MeV LINAC (to be upgraded to 400MeV), 3 GeV RCS and 50 (30 as phase I) GeV MR will be reported. Present status, including modification and improvement of instrumentations to meet with LINAC energy upgrade and a future plan will be reported with emphasis on high beam power related issues such as radiation hardness (mechanically and electrically), beam coupling impedance, etc..
	Slides TUOA01 [22.777 MB]

TUOA03	The Fermilab HINS Test Facility and Beam Measurements of the Ion Source and 325 MHz RFQ	diagnostics, rfq, proton, laser	283
	V.E. Scarpine, S. Chaurize, B.M. Hanna, S. Hays, J. Steimel, R.C. Webber, D. Wildman Fermilab, Batavia, USA
	Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359. The Fermilab High Intensity Neutrino Source (HINS) project is intended to test new concepts for low-energy, high-intensity superconducting linacs. HINS initial design consists of a 50 KeV ion source, a 2.5 MeV Radiofrequency Quadrupole (RFQ) followed by room temperature and superconducting spoke resonator acceleration sections. At present, a proton ion source and the 325 MHz RFQ, followed by a beam diagnostics section, have been operated with beam. This paper will present the beam measurement results for the proton ion source and for the 325 MHz RFQ module. In addition, this paper will discuss the role of HINS as a test facility for the development of beam diagnostic instrumentation required for future high-intensity linacs.
	Slides TUOA03 [1.864 MB]

TUOC01	Highlights from the 2010 Beam Instrumentation Workshop	instrumentation, ion, ECR, ion-source	297
	J.D. Gilpatrick LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the U.S. Department of Energy. The 14th Beam Instrumentation Workshop (BIW10) was hosted by the Los Alamos National Laboratory and was held in the La Fonda Hotel in downtown Santa Fe, NM, USA from May 3 – 6, 2010. At BIW10, there were a record amount of participants including 177 registered attendees, 92 poster presentations, and 22 companies represented. The oral presentations included 3 tutorials, 8 invited, 10 contributed, a Faraday Cup Award, 2 Vendor Technical, and 1 Special. This oral presentation provides an overview of beam instrumentation areas of interest, which were discussed during the workshop. From a selection of the BIW10 presented papers, a number of technical highlights will also be described. Finally, this oral presentation will briefly discuss the BIW10 Thursday afternoon tour that took place at the Los Alamos Neutron Science Center.
	Slides TUOC01 [3.110 MB]

TUPD02	Beam Diagnostics for the ESS	diagnostics, target, cryomodule, proton	302
	A. Jansson, L. Tchelidze ESS, Lund, Sweden
	The European Spallation Source (ESS) is a based on a 2.5GeV superconducting linac, producing a 5MW beam. Since it is optimized for cold neutrons, there is no accumulator ring, and hence no need for change exchange injection. Therefore, unlike most other proposed MW-class linacs, the ESS linac will accelerate protons rather than H⁻ ions. This poses a particular challenge for beam size mesurements in the superconducting section. This paper discusses the ESS beam diagnostics requirements, along with some possible instrument design options.

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

TUPD11	Developments for IFMIF/EVEDA LIPAc Beam Position Monitors: The Sensors at the MEBT and the Wire Test Bench	pick-up, controls, quadrupole, simulation	320
	I. Podadera, J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, E. Mirones, R. Unamuno, J.G.S. de la Gama CIEMAT, Madrid, Spain
	Funding: This work has been partially supported by the Spanish Ministry of Science and Innovation under Project ENE2009-11230 The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. In the Medium Energy Beam Transport line (MEBT) connecting the RFQ and the MEBT, non-interceptive Beam Position Monitors pickups (MBPMs) will measure the transverse position and phase in order to maximize the transport efficiency of the beamline. The response of the MBPMs must be optimized for a beam current for 5 MeV, and a peak beam current of 125 mA. Due to the lack of space in the MEBT, the MBPMs will be located inside the magnets. The MBPMs will have to fit inside the magnets without perturbing the magnetic field. In this contribution, the electromagnetic and mechanical design of the MBPM will be presented. In addition, in order to validate and characterize all the BPMs type of IFMIF/EVEDA once they are manufactured, a wire test bench has been constructed and verified at CIEMAT. The design and validation results of the test bench will be discussed.

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

TUPD18	Beam Position Monitors for the ACS Section of the J-PARC Linac	impedance, cavity, ion, simulation	341
	T. Miyao, Z. Igarashi, T. Toyama KEK, Ibaraki, Japan A. Miura JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC is consisted of Linac, 3GeV-RCS, and 50GeV-MR. We are aiming at the energy upgrade of J-PARC linac from 181MeV to 400MeV. We employed the ACS(Annular Coupled Structure) as the acceleration cavities. To have the energy upgrade, we need to develop beam instruments including beam position monitors (BPMs). Then, we designed them to be able to measure a horizontal and vertical beam position and employed a stripline-type as their electrodes. The BPMs are required to be calibrated to the accuracy of beam orbit within 100μm. To achieve the requirement, we did some calibrations. First, we decided a width of stripuline, whose characteristic impedance can be calibrated to 50 Ω with electric field simulations. Second, we also measured characteristic impedance of 4 different striplines per a BPM corresponding with BPM simulations. Last, we measured an electrical center position of BPMs with a simulated beam signal at 324MHz, 6dBm. A BPM will be installed at each quadrupole magnet in the ACS section to be used for a beam commissioning. Systematic calibration of developed BPMs is described in this paper. In addition, a phase measurement using these BPMs will be considered.

TUPD24	Design Status of Beam Position Monitors for the FAIR Proton Linac	proton, simulation, cavity, vacuum	356
	C.S. Simon, F. Senée CEA/DSM/IRFU, France G. Clemente, P. Forck, W. Kaufmann, P. Kowina GSI, Darmstadt, Germany
	Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

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

TUPD49	Performance of Parabolic and Diffusive OTR Screens at the CLIC Test Facility 3	dipole, diagnostics, alignment, simulation	413
	M. Olvegård, B. Bolzon, E. Bravin, S. Burger, A.E. Dabrowski, T. Lefèvre CERN, Geneva, Switzerland C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	At the CLIC Test Facility 3, OTR screens are commonly used in beam imaging systems for energy and energy spread characterization in dedicated spectrometer lines. In these lines the horizontal beam size is typically of the order of one centimeter. Already in 2005 a limitation was observed resulting from a strong dependence of the intensity of the light captured by the camera, on the position on the screen (vignetting). The severity of this effect increases with the electron energy, as the aperture of the optical system is finite and the OTR photons are emitted in a small cone of 1/γ angle. To mitigate this effect, different shapes and surface polishing of the screens were investigated. Parabolic and diffusive OTR radiators were tested in several spectrometer lines all along the CTF3 complex. The results are presented in this paper.

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

TUPD86	RF Reference Distribution and Timing System for the Taiwan Photon Source	gun, controls, synchrotron, booster	506
	C.Y. Wu, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a low-emittance 3-GeV synchrotron light source with circumference of 518.4 m (24 straight sections for installation of insertion devices), radio-frequency cavities and electron beam from the 150 MeV linac system which being in construction at National Synchrotron Radiation Research Center (NSRRC) campus. A high stability of the novel fiber based 500 MHz RF reference distribution is required and planned to use. Timing system for the TPS will be an event based system. It is based on 6U CompactPCI form factor from Micro-Research Finland Oy. Prototyping of the RF distribution and event system are on progress in this direction. The preliminary test results and implementation details will summary in this report.

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

TUPD92	SPIRAL2 Beam Energy Measurement	pick-up, simulation, rfq, instrumentation	524
	W. Le Coz, T.A. André, C. Doutresssoulles, C. Jamet, S. Loret GANIL, Caen, France
	In order to produce high intensity exotic beams in the existing experimental rooms of the GANIL facility, the SPIRAL2 project is under development and under construction at GANIL. The first phase of the SPIRAL2 project consists to build a new accelerator composed of two sources, an ion source and a proton/neutron source, a RFQ and a superconducting Linac. The linac is designed to accelerate 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. A new electronic device has been developed at GANIL to measure phase and amplitude of pick-up signals and calculate the beam energy. The principle consists of directly digitizing the pick-up pulses by under-sampling. The Phase and amplitude of different harmonics are then calculated with a FPGA by an I/Q method before the beam energy calculation. This paper gives results of the peak-up tests in laboratory and the comparisons with simulations. The tests in laboratory and on the GANIL accelerator of an electronic prototype are shown and presented.

TUPD96	Fast and Critical Detection Devices Planned for the Machine Protection System at the Facility for Rare Isotope Beams	controls, status, EPICS, beam-losses	533
	G. Kiupel, S. Assadi, T.D. Brown, P. Chu, J.L. Crisp, S. Peng, M.W. Stettler, Y. Zhang FRIB, East Lansing, Michigan, USA
	Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) will use a 400 kW, heavy-ion cw linac to produce rare isotopes in support of a rich program of fundamental research. In the event of operational failures, the Machine Protection System (MPS) shuts off the beam within microseconds to control beam losses that may damage accelerator components. The operational mode is distributed to all fast and critical devices that have multiple hardware checkpoints and comparators. A relational database provides the framework for the development of the MPS management application. In this paper, we present the FRIB MPS architecture, plans and implementation.

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

WEOC01	Beam Charge Measurements	vacuum, coupling, impedance, pick-up	564
	D. Belohrad CERN, Geneva, Switzerland
	The measurement of beam charge is fundamental to all particle accelerators. There exist many methods to achieve this, which can broadly be classified into two categories: intercepting measurements, which are destructive for the beam and result in absorption of a significant amount of energy; non-intercepting measurements using electric or magnetic field coupling. In both categories one can find instruments that process the beam signals with high dynamic range, both in amplitude and time. The aim of this article is to present the current state of beam charge measurement technology. Various measurement methods will be described with their uses, advantages, and achievable resolution and accuracy discussed. The technological problems related to their fabrication will also be addressed.
	Slides WEOC01 [5.738 MB]

Paper

Title

Other Keywords

Page

MOOB04

Bunch Compression, RF Curvature Correction and R₅₅, T₅₅₅ and U₅₅₅₅ Measurements at JLab FEL

FEL, cavity, SRF, sextupole

15

P. Evtushenko, S.V. Benson, D. Douglas
JLAB, Newport News, Virginia, USA

The JLab IR/UV FEL Upgrade operates with the bunch length compressed down to 100-150 fs RMS. An indispensible part of the bunch compression scheme is the correction of the so-called LINAC RF curvature. Unlike other systems – where the RF curvature gets corrected using higher a harmonic LINAC – our system utilizes magnetic elements of the beam transport system to correct and adjust the second and third order correlation terms. These are expressed in terms of the transport matrix elements T₅₆₆ and U₅₆₆₆. The linear correlation term described by M₅₅ is adjusted using the magnetic system as well. The large energy spread induced on the beam by the FEL operation is compressed as a part of the energy recovery process. As in the case of bunch length compression, this energy compression is optimized by properly adjusting high order transport matrix elements. In this contribution we describe the system used for direct measurements of the transport matrix elements M₅₅, T₅₆₆ and U₅₆₆₆ and its impact on the operation and bunch compression. Results of the measurements are presented together with the bunch length measurements including the data showing resolution and accuracy of the system.

Slides MOOB04 [0.999 MB]

MOOC01

Overview of Recent Trends and Developments for BPM Systems

cavity, pick-up, coupling, monitoring

18

M. Wendt
Fermilab, Batavia, USA

Beam position monitoring (BPM) systems are the workhorse beam diagnostics for almost any kind of charged particle accelerator; linear, circular or transport-lines, operating with leptons, hadrons or heavy ions. The BPMs are essential for beam commissioning, accelerator fault analysis and trouble shooting, machine optics and lattice measurements, and finally for the accelerator optimization to achieve the ultimate beam quality. This presentation summarizes the efforts of the beam instrumentation community on recent developments and advances on BPM technologies, i.e. BPM pickup monitors and front-end electronics (analog and digital). Principles, examples, and state-of-the-art status on various BPM techniques are outlined, serving hadron and heavy ion machines, sync light synchrotron's, as well as electron linacs for FEL or HEP applications.

Slides MOOC01 [4.123 MB]

MOPD07

Newly Installed Beam Diagnostics at the Australian Synchrotron

injection, booster, synchrotron, diagnostics

47

E.D. van Garderen, M.J. Boland, G. LeBlanc, B. Mountford, A. Rhyder, A. C. Starritt, A. Walsh, K. Zingre
ASCo, Clayton, Victoria, Australia

The Australian Synchrotron (AS) is aiming at implementing Top-Up operations in 2012. To reduce costs only one of the two klystrons in the linac will be used. The electron beam in the linac will only be accelerated to 80 MeV, instead of 100 MeV achieved currently. The injection system will need to be recommissioned. The beam position monitors in the booster have been upgraded and YAG:Ce screens have been added to the booster-to-storage ring (BTS) transfer line. In addition the injection efficiency will be optimized and monitored. For this purpose another Fast Current Transformer has also been installed at the end of the BTS.

MOPD08

Beam Diagnostics in the J-PARC Linac for ACS Upgrade

diagnostics, pick-up, acceleration, simulation

50

A. Miura, S. Sato
JAEA/J-PARC, Tokai-mura, Japan
Z. Igarashi, M. Ikegami, T. Miyao, T. Toyama
KEK, Ibaraki, Japan
T. Tomisawa
JAEA/LINAC, Ibaraki-ken, Japan

J-PARC had developed the beam diagnostic devices for the current J-PARC linac and has used them since the operation start. J-PARC linac began the energy upgrade project since 2009 and 21 ACS cavities will be installed. In this project, many cavities and related devices are newly installed in the ACS section and its downstream part. Because the beam parameters are updated, new beam diagnostic devices are fabricated and current diagnostic devices are developed. Beam position monitors (BPM) are newly designed and fabricated, based on the computer simulation and bench test. Because the gas proportional BLMs as the current BLM are sensitive to background noise of X-ray emitted from RF cavities, it is difficult to recognize real beam loss. We need to subtract an X-ray noise from the signal from BLM, another candidate BLMs have been tried to measure the beam loss. In addition, the bunch shape monitor for the longitudinal tuning has been developed in the corroboration with the institute for nuclear research, Russia. In this paper, we describe the new developed devices and their development process, especially for beam loss monitor and the developing bunch shape monitor.

MOPD19

Button BPM Development for the European XFEL

simulation, vacuum, cryogenics, cavity

83

D. Lipka, B. Lorbeer, D. Nölle, M. Siemens, S. Vilcins
DESY, Hamburg, Germany

Button beam position monitors will be the main BPM type used to measure the electron beam position at the European XFEL. Two different kinds of buttons are necessary: one type will be installed in the acceleration modules of the cold linac and the other in the warm environment. The electro-magnetic design of the feedthrough for both types of buttons will be discussed. A comparison of the designed and measured RF properties will be presented. In addition to the usual RF properties, also the properties at cryogenic level will play a role. HOM power must not heat up the BPM feedthroughs, in order to keep the cryo load of an overall accelerator module low, and also to prevent damage due to large temperature gradients over the ceramics of the feedthrough. First measurements with beam at FLASH show good agreement of the measured signals with the expectation.

MOPD21

Overview of the BPM System of the ESS-Bilbao

controls, EPICS, LLRF, impedance

89

D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo
ESS-Bilbao, Zamudio, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Jugo, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
N. Garmendia, L. Muguira
ESS Bilbao, Bilbao, Spain

The BPM system from ESS-Bilbao is presented, including test bench, electronics and test results. Our test bench implements 4 capacitive buttons welded to the beam pipe. The position of the internal tube simulating the beam can be changed with respect to the outer tube within a range of 20 mm, with a resolution less than 10 μm. It is connected to an Analog Front-End (AFE) where signals are conditioned and converted to baseband and a Digital Unit (DU) to sample them and calculate the position and phase. The AFE is based on logarithmic amplifiers and IQ demodulators. Signals are converted from differential to single-ended and conditioned to meet the DU requirements (FPGA and ADC). DU includes offset compensation, gain adjustment, CORDIC, delta over σ algorithm and linearization blocks. To manage the FPGA a Java interface has been developed including also the EPICS integration by means of JavaIOC and a MySQL interface. The resolution and accuracy results are promising (less than 10 μm and 1° for the position and phase) provided that the effect of several errors such as temperature variations and nonlinearities are minimized through temperature regulation and system calibration.

Poster MOPD21 [1.476 MB]

MOPD35

Improved Signal Treatment for Capacitive Linac Pick-Ups

pick-up, DTL, rfq, radio-frequency

128

A. Reiter, C.M. Kleffner, B. Schlitt
GSI, Darmstadt, Germany

Phase probes are a crucial diagnostic tool for pulsed particle beams of linear accelerators. In this contribution we present a simple, but very effective analysis procedure which has been established in various applications during commissioning campaigns of injector linacs for medical facilities. These injectors consist of a 400 keV/u radio-frequency quadrupole followed by a 7 MeV/u inter-digital drift tube linac, both operating at 216.8 MHz. At GSI, the new analysis was recently applied at the HITRAP decelerator, also with promising results. The data analysis exploits the periodic nature of sampling process and bunch signal improving the detector sensitivity and achieving an effective resolution of < 10 ps. If the macro-pulse is sufficiently long, the quality of the data can be improved further by a statistical average of subsequent data blocks acquired within one single macro-pulse. The latter is important for experiments with low beam intensity and low repetition rate like HITRAP where averaging over many macro-pulses is cumbersome.

MOPD36

Development of a Silicon Detector Monitor for the Superconducting Upgrade of the REX-ISOLDE Heavy-Ion Linac at CERN

cavity, ion, diagnostics, rfq

131

F. Zocca
IEM, Madrid, Spain
E. Bravin, M.A. Fraser, D. Voulot, F.J.C. Wenander, F. Zocca
CERN, Geneva, Switzerland
M. Pasini
Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium

A silicon detector monitor has been developed and tested in the frame of the beam diagnostics development program for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac at CERN. The monitor is intended for beam energy and timing measurements as well as for phase scanning of the superconducting cavities. Tests have been performed with a stable ion beam, composed of carbon, oxygen and neon ions accelerated to energies from 300 keV/u to 2.85 MeV/u. The silicon detector was placed directly in the beam line and tested with a beam which was strongly attenuated to simulate the single particle detection regime for which the monitor is intended to finally function. The energy measurements performed allowed for beam spectroscopy and ion identification with a resolution of 3%. The principle of cavity phase scanning was also demonstrated with the REX 7-gap resonator thanks to the accurate peak energy identification. The time structure of the beam, characterized by a bunch period of 9.87 ns, was measured with a resolution better than 200 ps. This paper describes the results from all these tests as well as providing details of the detector.

MOPD42

μ-loss Detector for IFMIF-EVEDA

neutron, solenoid, cryomodule, focusing

146

J. Marroncle, P. Abbon, J. Egberts
CEA/DSM/IRFU, France
M. Pomorski
CEA/DRT/LIST, Gif-sur-Yvette Cedex, France

For the IFMIF-EVEDA project, a prototype accelerator is being built in Europe and installed at Rokkasho (Japan). It is designed to accelerate 125 mA CW Deuteron to 9 MeV. The very high space charge and high power (1.125 MW) of the beam make this accelerator very challenging. For hands-on maintenance requirements, losses must be well less than 1W/m, i.e. 10^-6 of the beam. That is why, in the 5-9 MeV superconducting Linac, beam dynamics physicists search to tune the beam by minimizing the very external part of the halo. The need is thus to be able to measure very tiny beam losses, called μ-losses, at all the focusing magnets. Only neutrons and γ exit from the beam pipe due to the low deuteron beam energy. Thus such beam loss detectors have to be sensitive to neutrons, but rather insensitive for X-rays and γ to decrease their contributions coming from super-conducting cavity emission. They must be radiation hardness qualified, and capable to work at cryogenic temperature. Single CVD diamonds (4×4×0.5 mm³) are studied for these purposes and first results seem to fulfill the requirements up to now.

MOPD43

Beam Loss Detected by Scintillation Monitor

hadron, background, simulation, quadrupole

149

A. Miura, T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
K. Hasegawa, N. Ouchi, H. Sako
JAEA, Ibaraki-ken, Japan
Z. Igarashi, M. Ikegami, T. Miyao
KEK, Ibaraki, Japan

Ar gas proportional BLMs have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. We have tried to measure the beam loss using scintillation monitors which would bring more accurate beam loss measurements with suppression of X-ray noise. We measured beam loss using scintillation beam loss monitors. Because this scintillation BLM is sensitive for low energy gamma-rays and fast neutrons, small signals from X-rays would be also detected. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. And many single events are observed in the intermediate pulse bunch with about 600 ns as pulse width. After all signals passed through the filter circuit and integrated circuit, total amount of X-ray noise can become smaller. We obtained the good performances of scintillation BLM with small effect of X-ray noise. This monitor can be used for beam loss measurement and a knob for tuning. Furthermore, because the detail structure can be detected, this monitor could be employed for another diagnostic device.

MOPD49

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

emittance, radiation, ion, proton

161

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

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

MOPD52

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

emittance, solenoid, rfq, proton

167

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

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

MOPD57

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

ion, emittance, target, alignment

179

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

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

MOPD66

Upgrade of the CERN PSB/CPS Fast Intensity Measurements

synchrotron, proton, booster, status

200

A. Monera Martinez, M. Andersen, D. Belohrad, L.K. Jensen, L. Søby
CERN, Geneva, Switzerland
G. Kasprowicz
CREOTECH Ltd., Warsaw, Poland

The CERN Proton Synchrotron Booster (PSB) and Proton Synchrotron (CPS) complex fast intensity measurement is undergoing a major upgrade. The old analogue electronics no longer provides enough accuracy, resolution and versatility to perform accurate beam intensity measurements. It has also become less reliable due to the ageing equipment. A new measurement system - Transformer Integrator Card (TRIC) - replaces these obsolete acquisition systems. TRIC is a generic platform used to measure the intensity in different transfer lines at CERN. Five TRICs were installed during the year 2010 in order to evaluate their performance with different beam types, from the low intensity pilot (5×10⁹ charges per bunch) to high intensity beams (1×10¹³ charges per bunch). The aim of this article is to present the technical aspects of the new system and the different measurement scenarios. It discusses possible sources of measurement errors and presents some statistical data acquired during this period.

MOPD85

Beam Emittance Studies at the Heavy Ion Linac UNILAC

emittance, rfq, ion, DTL

245

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

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

Poster MOPD85 [10.077 MB]

MOPD97

Beam Position Monitor System for the CERN Linac4

pick-up, simulation, DTL, resonance

272

J. Tan, L. Søby, M. Sordet
CERN, Geneva, Switzerland

The new LINAC4 will provide 160 MeV H¯ ion beams for charge-exchange and proton injection into the CERN accelerator complex. Among a wide variety of beam diagnostics devices, shorted stripline pick-ups will measure the absolute beam position, the relative and absolute beam current, and the average beam energy via the time-of-flight between two monitors. This paper describes the beam position monitor (BPM) with its electronic acquisition chain to be implemented on the movable test bench for beam characterization up to 12 MeV.

TUOA01

Beam Instrumentation in J-PARC

feedback, impedance, proton, septum

275

T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The talk will summarize the beam instrumentation at J-PARC with a focus on MW class proton beams. The measurements of beam intensities, positions, losses, profiles, and halos at each stage of accelerator, 181 MeV LINAC (to be upgraded to 400MeV), 3 GeV RCS and 50 (30 as phase I) GeV MR will be reported. Present status, including modification and improvement of instrumentations to meet with LINAC energy upgrade and a future plan will be reported with emphasis on high beam power related issues such as radiation hardness (mechanically and electrically), beam coupling impedance, etc..

Slides TUOA01 [22.777 MB]

TUOA03

The Fermilab HINS Test Facility and Beam Measurements of the Ion Source and 325 MHz RFQ

diagnostics, rfq, proton, laser

283

V.E. Scarpine, S. Chaurize, B.M. Hanna, S. Hays, J. Steimel, R.C. Webber, D. Wildman
Fermilab, Batavia, USA

Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.
The Fermilab High Intensity Neutrino Source (HINS) project is intended to test new concepts for low-energy, high-intensity superconducting linacs. HINS initial design consists of a 50 KeV ion source, a 2.5 MeV Radiofrequency Quadrupole (RFQ) followed by room temperature and superconducting spoke resonator acceleration sections. At present, a proton ion source and the 325 MHz RFQ, followed by a beam diagnostics section, have been operated with beam. This paper will present the beam measurement results for the proton ion source and for the 325 MHz RFQ module. In addition, this paper will discuss the role of HINS as a test facility for the development of beam diagnostic instrumentation required for future high-intensity linacs.

Slides TUOA03 [1.864 MB]

TUOC01

Highlights from the 2010 Beam Instrumentation Workshop

instrumentation, ion, ECR, ion-source

297

J.D. Gilpatrick
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the U.S. Department of Energy.
The 14th Beam Instrumentation Workshop (BIW10) was hosted by the Los Alamos National Laboratory and was held in the La Fonda Hotel in downtown Santa Fe, NM, USA from May 3 – 6, 2010. At BIW10, there were a record amount of participants including 177 registered attendees, 92 poster presentations, and 22 companies represented. The oral presentations included 3 tutorials, 8 invited, 10 contributed, a Faraday Cup Award, 2 Vendor Technical, and 1 Special. This oral presentation provides an overview of beam instrumentation areas of interest, which were discussed during the workshop. From a selection of the BIW10 presented papers, a number of technical highlights will also be described. Finally, this oral presentation will briefly discuss the BIW10 Thursday afternoon tour that took place at the Los Alamos Neutron Science Center.

Slides TUOC01 [3.110 MB]

TUPD02

Beam Diagnostics for the ESS

diagnostics, target, cryomodule, proton

302

A. Jansson, L. Tchelidze
ESS, Lund, Sweden

The European Spallation Source (ESS) is a based on a 2.5GeV superconducting linac, producing a 5MW beam. Since it is optimized for cold neutrons, there is no accumulator ring, and hence no need for change exchange injection. Therefore, unlike most other proposed MW-class linacs, the ESS linac will accelerate protons rather than H⁻ ions. This poses a particular challenge for beam size mesurements in the superconducting section. This paper discusses the ESS beam diagnostics requirements, along with some possible instrument design options.

TUPD04

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

diagnostics, emittance, site, electron

308

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

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

TUPD11

Developments for IFMIF/EVEDA LIPAc Beam Position Monitors: The Sensors at the MEBT and the Wire Test Bench

pick-up, controls, quadrupole, simulation

320

I. Podadera, J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, E. Mirones, R. Unamuno, J.G.S. de la Gama
CIEMAT, Madrid, Spain

Funding: This work has been partially supported by the Spanish Ministry of Science and Innovation under Project ENE2009-11230
The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. In the Medium Energy Beam Transport line (MEBT) connecting the RFQ and the MEBT, non-interceptive Beam Position Monitors pickups (MBPMs) will measure the transverse position and phase in order to maximize the transport efficiency of the beamline. The response of the MBPMs must be optimized for a beam current for 5 MeV, and a peak beam current of 125 mA. Due to the lack of space in the MEBT, the MBPMs will be located inside the magnets. The MBPMs will have to fit inside the magnets without perturbing the magnetic field. In this contribution, the electromagnetic and mechanical design of the MBPM will be presented. In addition, in order to validate and characterize all the BPMs type of IFMIF/EVEDA once they are manufactured, a wire test bench has been constructed and verified at CIEMAT. The design and validation results of the test bench will be discussed.

TUPD13

CLIC Drive Beam Position Monitor

electron, damping, luminosity, coupling

326

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

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

TUPD18

Beam Position Monitors for the ACS Section of the J-PARC Linac

impedance, cavity, ion, simulation

341

T. Miyao, Z. Igarashi, T. Toyama
KEK, Ibaraki, Japan
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC is consisted of Linac, 3GeV-RCS, and 50GeV-MR. We are aiming at the energy upgrade of J-PARC linac from 181MeV to 400MeV. We employed the ACS(Annular Coupled Structure) as the acceleration cavities. To have the energy upgrade, we need to develop beam instruments including beam position monitors (BPMs). Then, we designed them to be able to measure a horizontal and vertical beam position and employed a stripline-type as their electrodes. The BPMs are required to be calibrated to the accuracy of beam orbit within 100μm. To achieve the requirement, we did some calibrations. First, we decided a width of stripuline, whose characteristic impedance can be calibrated to 50 Ω with electric field simulations. Second, we also measured characteristic impedance of 4 different striplines per a BPM corresponding with BPM simulations. Last, we measured an electrical center position of BPMs with a simulated beam signal at 324MHz, 6dBm. A BPM will be installed at each quadrupole magnet in the ACS section to be used for a beam commissioning. Systematic calibration of developed BPMs is described in this paper. In addition, a phase measurement using these BPMs will be considered.

TUPD24

Design Status of Beam Position Monitors for the FAIR Proton Linac

proton, simulation, cavity, vacuum

356

C.S. Simon, F. Senée
CEA/DSM/IRFU, France
G. Clemente, P. Forck, W. Kaufmann, P. Kowina
GSI, Darmstadt, Germany

Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

TUPD30

Bunch Length Measurement using Coherent Cherenkov Radiation

electron, laser, gun, injection

368

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

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

TUPD49

Performance of Parabolic and Diffusive OTR Screens at the CLIC Test Facility 3

dipole, diagnostics, alignment, simulation

413

M. Olvegård, B. Bolzon, E. Bravin, S. Burger, A.E. Dabrowski, T. Lefèvre
CERN, Geneva, Switzerland
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

At the CLIC Test Facility 3, OTR screens are commonly used in beam imaging systems for energy and energy spread characterization in dedicated spectrometer lines. In these lines the horizontal beam size is typically of the order of one centimeter. Already in 2005 a limitation was observed resulting from a strong dependence of the intensity of the light captured by the camera, on the position on the screen (vignetting). The severity of this effect increases with the electron energy, as the aperture of the optical system is finite and the OTR photons are emitted in a small cone of 1/γ angle. To mitigate this effect, different shapes and surface polishing of the screens were investigated. Parabolic and diffusive OTR radiators were tested in several spectrometer lines all along the CTF3 complex. The results are presented in this paper.

TUPD59

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

electron, simulation, laser, FEL

440

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

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

TUPD86

RF Reference Distribution and Timing System for the Taiwan Photon Source

gun, controls, synchrotron, booster

506

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

Taiwan Photon Source (TPS) is a low-emittance 3-GeV synchrotron light source with circumference of 518.4 m (24 straight sections for installation of insertion devices), radio-frequency cavities and electron beam from the 150 MeV linac system which being in construction at National Synchrotron Radiation Research Center (NSRRC) campus. A high stability of the novel fiber based 500 MHz RF reference distribution is required and planned to use. Timing system for the TPS will be an event based system. It is based on 6U CompactPCI form factor from Micro-Research Finland Oy. Prototyping of the RF distribution and event system are on progress in this direction. The preliminary test results and implementation details will summary in this report.

TUPD89

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

electron, laser, polarization, photon

515

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

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

TUPD92

SPIRAL2 Beam Energy Measurement

pick-up, simulation, rfq, instrumentation

524

W. Le Coz, T.A. André, C. Doutresssoulles, C. Jamet, S. Loret
GANIL, Caen, France

In order to produce high intensity exotic beams in the existing experimental rooms of the GANIL facility, the SPIRAL2 project is under development and under construction at GANIL. The first phase of the SPIRAL2 project consists to build a new accelerator composed of two sources, an ion source and a proton/neutron source, a RFQ and a superconducting Linac. The linac is designed to accelerate 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. A new electronic device has been developed at GANIL to measure phase and amplitude of pick-up signals and calculate the beam energy. The principle consists of directly digitizing the pick-up pulses by under-sampling. The Phase and amplitude of different harmonics are then calculated with a FPGA by an I/Q method before the beam energy calculation. This paper gives results of the peak-up tests in laboratory and the comparisons with simulations. The tests in laboratory and on the GANIL accelerator of an electronic prototype are shown and presented.

TUPD96

Fast and Critical Detection Devices Planned for the Machine Protection System at the Facility for Rare Isotope Beams

controls, status, EPICS, beam-losses

533

G. Kiupel, S. Assadi, T.D. Brown, P. Chu, J.L. Crisp, S. Peng, M.W. Stettler, Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) will use a 400 kW, heavy-ion cw linac to produce rare isotopes in support of a rich program of fundamental research. In the event of operational failures, the Machine Protection System (MPS) shuts off the beam within microseconds to control beam losses that may damage accelerator components. The operational mode is distributed to all fast and critical devices that have multiple hardware checkpoints and comparators. A relational database provides the framework for the development of the MPS management application. In this paper, we present the FRIB MPS architecture, plans and implementation.

TUPD97

Diagnostic System of TAC IR FEL Facility

electron, FEL, emittance, diagnostics

536

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

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

Poster TUPD97 [0.514 MB]

WEOC01

Beam Charge Measurements

vacuum, coupling, impedance, pick-up

564

D. Belohrad
CERN, Geneva, Switzerland

The measurement of beam charge is fundamental to all particle accelerators. There exist many methods to achieve this, which can broadly be classified into two categories: intercepting measurements, which are destructive for the beam and result in absorption of a significant amount of energy; non-intercepting measurements using electric or magnetic field coupling. In both categories one can find instruments that process the beam signals with high dynamic range, both in amplitude and time. The aim of this article is to present the current state of beam charge measurement technology. Various measurement methods will be described with their uses, advantages, and achievable resolution and accuracy discussed. The technological problems related to their fabrication will also be addressed.

Slides WEOC01 [5.738 MB]