IBIC2014 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPF07	Construction and Operational Performance of a Horizontally Adjustable Beam Profile Monitor at NSLS-II	injection, storage-ring, septum, controls	55
	B.N. Kosciuk, A. Blednykh, S. Seletskiy BNL, Upton, Long Island, New York, USA
	The NSLS-II Synchrotron Light Source is a 3 GeV electron storage ring currently in the early stages of commissioning at Brookhaven National Laboratory. In order to observe the electron beam cross section in the injection region, a specially designed, horizontally adjustable beam profile monitor was installed at the downstream end of the injection septum. It allows the profiles of the injected, bumped and single turn beam to be viewed and measured. In this presentation, we discuss the final design, construction challenges, and operational performance of this novel device.
	Poster MOPF07 [0.953 MB]
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MOPF16	CERN-SPS Wire Scanner Impedence and Wire Heating Studies	coupling, simulation, electromagnetic-fields, emittance	88
	E. Piselli, O.E. Berrig, F. Caspers, B. Dehning, J. Emery, M. Hamani, J. Kuczerowski, B. Salvant, R.S. Sautier, R. Veness, C. Vuitton, C. Zannini CERN, Geneva, Switzerland
	This article describes a study performed on one of the SPS vertical rotational wire scanners in order to investigate the breakage of the wire, which occurred on several occasions during the last year of operation. The thermionic emission current of the wire was measured to evaluate temperature changes, and was observed to rise significantly as the wire approached the ultimate LHC beam in the SPS, indicating the possibility of strong coupling between the beam’s electromagnetic field and the wire. Different laboratory measurements, complemented by CST Microwave Studio simulations, have therefore been performed to try and understand the RF modes responsible for this heating. These results are presented here, along with the subsequent modifications adopted on all of the operational SPS wire scanners.
	Poster MOPF16 [0.747 MB]
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MOPF19	Design of a Profile Monitor with 12 Inches of Actuation for FRIB	alignment, diagnostics, interface, feedback	97
	S. Rodriguez Esparza, G. Kiupel, I.N. Nesterenko FRIB, East Lansing, Michigan, USA
	Funding: FACILITY FOR RARE ISOTOPE BEAMS Actuated diagnostics present additional challenges that static diagnostics devices do not such as alignment, stability, and incorporating an appropriate drive mechanism. These challenges become even more apparent as the actuaded length increases. At the Facility for Rare Isotope Beams (FRIB) we plan on using a number of actuated diagnostics devices including a Profile Monitor (AKA: Wire Scanner) with 12 inches of actuation. The Profile Monitor uses tungsten wires to traverse the beam pipe aperture to measure the beam intensity with respect to it’s location in the X-Y plane. This paper will detail the design of the 12 inch Profile Monitor and how it is able to overcome the stability, alignment, and drive issues that come with the 12 inches of actuation.
	Poster MOPF19 [1.128 MB]
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MOPF31	Overview of Beam Instrumentation Activities for SwissFEL	electron, radiation, undulator, pick-up	119
	R. Ischebeck, R. Abela, F. Ardana-Lamas, V.R. Arsov, R. Baldinger, H.-H. Braun, M. Calvi, R. Ditter, C. Erny, F. Frei, R. Ganter, I. Gorgisyan, C.P. Hauri, S. Hunziker, P.N. Juranic, B. Keil, W. Koprek, R. Kramert, D. Llorente Sancho, F. Löhl, F. Marcellini, G. Marinkovic, B. Monoszlai, G.L. Orlandi, C. Ozkan, L. Patthey, M. Pedrozzi, P. Pollet, M. Radovic, L. Rivkin, M. Roggli, M. Rohrer, V. Schlott, A.G. Stepanov, J. Stettler PSI, Villigen PSI, Switzerland F. Ardana-Lamas, I. Gorgisyan, C.P. Hauri, L. Rivkin EPFL, Lausanne, Switzerland P. Peier DESY, Hamburg, Germany
	SwissFEL will provide users with brilliant X-ray pulses in 2017. A comprehensive suite of diagnostics is needed for the initial commissioning, for changes to the operating point, and for feedbacks. The development of instrumentation for SwissFEL is well underway, and solutions have been identified for most diagnostics systems. I will present here an overview of the instrumentation for SwissFEL, and give details on some recent developments.
	Poster MOPF31 [4.418 MB]
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TUCYB3	SwissFEL Beam Profile Monitor	radiation, electron, laser, detector	259
	R. Ischebeck, E. Prat, V. Schlott, V.G. Thominet PSI, Villigen PSI, Switzerland P. Krejcik, H. Loos SLAC, Menlo Park, California, USA M. Yan DESY, Hamburg, Germany
	We have developed a beam profile monitor that allows us to measure two-dimensional electron beam profiles for highly compressed electron bunches. Such bunches have plagued profile measurements in optical transition radiation monitors in the past, because coherent radiation entering the optical system has invalidated the images and even destroyed cameras. The present design makes use of a scintillating crystal, and directs coherent transition radiation away from the optical axis by careful choice of the angle. When observing Snell's law of refraction as well as the Scheimpflug imaging condition, a resolution better than the thickness of the scintillator can be achieved. We will present measurements performed at the SwissFEL Injector Test Facility and at the Linac Coherent Light Source. The high resolution and excellent sensitivity of this monitor make it ideal for installation in SwissFEL.
	Slides TUCYB3 [42.624 MB]
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TUCZB3	A Quantum Gas Jet for Non-Invasive Beam Profile Measurement	ion, focusing, photon, electron	284
	A. Jeff, E.B. Holzer, T. Lefèvre CERN, Geneva, Switzerland A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom V. Tzoganis, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom
	A novel instrument for accelerator beam diagnostics is being developed by using De Broglie-wave focusing to create an ultra-thin neutral gas jet. Scanning the gas jet across a particle beam while measuring the interaction products, the beam profile can be measured. Such a jet scanner will provide an invaluable diagnostic tool in beams which are too intense for the use of wire scanners, such as the proposed CLIC Drive Beam. In order to create a sufficiently thin jet, a focusing element working on the DeBroglie wavelength of the Helium atom has been designed. Following the principles of the Photon Sieve, we have constructed an Atomic Sieve consisting of 5230 nano-holes etched into a thin film of silicon nitride. When a quasi-monochromatic Helium jet is incident on the sieve, an interference pattern with a single central maximum is created. The stream of Helium atoms passing through this central maximum is much narrower than a conventional gas jet. The first experiences with this device are presented here, along with plans for further tests.
	Slides TUCZB3 [13.880 MB]
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TUPF03	Overview of the Geometrical Non-Linear Effects of Button BPMs and Methodology for Their Efficient Suppression	pick-up, simulation, coupling, storage-ring	298
	A.A. Nosych, U. Iriso, A. Olmos ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain M. Wendt CERN, Geneva, Switzerland
	This paper describes an overview of the geometric non-linear effects common to beam position monitors (BPMs) installed in the accelerators and a methodology to correct for these effects. A typical characteristic curve of a pick-up is linear within a limited range from the BPM origin. At larger offsets the non-linearity of the curve is more pronounced and gets worse if the button diameter is small with respect to the beam pipe diameter. The general real-time linearization methods usually utilize linear correction combined with a simplistic polynomial, which may lead to inaccuracies in their limited application. We have developed a more rigorous methodology to suppress the non-linear effects of the BPMs through electromagnetic (EM) simulations and 2D fitting approximations. The focus is mainly on standard button pick-ups for the electron (ALBA) and proton machines (LHC).
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TUPF04	Numerical Calculations for the FAIR Proton Linac BPMs	linac, simulation, proton, pick-up	303
	C.S. Simon CEA/DSM/IRFU, France M.H. Almalki, P. Forck, W. Kaufmann, T. Sieber GSI, Darmstadt, Germany V. Bellego CEA/IRFU, Gif-sur-Yvette, France
	Fourteen Beam Position Monitors (BPMs) will be installed along the FAIR Proton LINAC. These monitors will be used to determine the beam position, the relative beam current and the mean beam energy by time of flight (TOF). A capacitive button type pickup was chosen for its easy mechanical realization and for the short insertion length which is important for the four BPMs locations of the inter-tank sections between the CH-cavities. Depending on the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, limited space for installation and a 30 mm or 50 mm beam pipe aperture. This paper reports wake field numerical simulations performed by the code CST PARTICLE STUDIO to design and characterize the BPMs. Time of response of monitors are presented and results of calculations for various pickup-geometries are discussed taking into account different beam velocities.
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TUPF05	Production Process for the European XFEL Re-Entrant Cavity BPM	cavity, cryomodule, quadrupole, controls	307
	C.S. Simon, P. Carbonnier, P. Contrepois, F. Éozénou, Y. Gasser, O. Napoly, J. Novo, C. Servouin CEA/DSM/IRFU, France C. Boulch, Y. Gasser CEA/IRFU, Gif-sur-Yvette, France P. Daniel-Thomas, F. Gouit CEA, Gif-sur-Yvette, France J. Kruse, D. Nölle, M. Schalwat, S. Vilcins DESY, Hamburg, Germany N. Rouvière IPN, Orsay, France
	As In-Kind contributor to the E-XFEL project, CEA is committed to the procurement of around one third (31) cold beam position monitors (BPM) of the re-entrant RF cavities type and to the assembly on the Saclay site of the 101 cryomodules of the superconducting linac. Each cryomodule is equipped with a beam position monitor connected to a quadrupole at the high-energy end of the cavity string. The industrial process of those BPMs, used in an ultra-clean environment at cryogenic temperature, includes several steps and involves a quality control in collaboration with industrial partners. This paper describes the different steps of the re-entrant cavity BPM fabrication process: machining, copper coating, thermal treatment, EB welding, cleaning and mounting in clean room on the quadrupole. Problems encountered and the lessons learnt will be also reported.
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TUPF11	Mechanical Design of Cryogenic Vacuum Feedthroughs for X-FEL Button BPMs	cryogenics, simulation, project-management, operation	332
	S. Vilcins, D. Lipka DESY, Hamburg, Germany
	The European XFEL is a 4th generation synchrotron radiation source, currently under construction in Hamburg. Based on different Free-Electron Laser and spontaneous sources and driven by a superconducting accelerator, it will be able to provide several user stations with photons simultaneously. Due to the superconducting technology in the accelerators modules many components have to operate at liquid helium temperature. This poster will concentrate on high frequency ultra high vacuum feedthrough used for the beam position monitors of the cryogenic accelerator modules. Main emphasis will be put on the design of these feedthroughs, their material composition and the production process. The capability to be used under these very special conditions was investigated with FEM simulations, as well as with a test procedure. The results of these simulations will be presented; the tests and their results will be explained in detail.
	Poster TUPF11 [0.407 MB]
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TUPF14	Newly Developed 6mm Buttons for the BPMs in the ESRF Low-Emittance-Ring	coupling, factory, simulation, operation	346
	K.B. Scheidt ESRF, Grenoble, France
	For the small beam pipe of the BPMs in the LE-ring a development of 6mm button-UHV-feedthroughs was launched and has resulted in the delivery of a total of 27 prototypes from both the Kyocera and the PMB-ALCEN companies. These buttons are flat, without skirt, with a central pin of Molybdenum ending in a male SMA connector. Among these prototype units are versions with Copper, Steel and Molybdenum material for the button itself, with the aim of assessing possible different heatload issues. All design considerations, that are compatible with a further button reduction to 4mm, will be presented next to issues of costs, mechanical tolerances and feasibility.
	Poster TUPF14 [1.420 MB]
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TUPF23	Beam Size Measurements using Synchrotron Radiation Interferometry at ALBA	radiation, extraction, synchrotron, synchrotron-radiation	374
	L. Torino, U. Iriso ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain T.M. Mitsuhashi KEK, Ibaraki, Japan
	First tests to measure the transverse beam size using interferometry at ALBA showed that the measurement reliability was limited by the inhomogeneous light wavefront arriving at the double slit system. For this reason, the optical components guiding the synchrotron radiation have been exchanged, and detailed quality checks have been carried out using techniques like the Fizeau interferometry or Hartmann mask tests. We report the results of the analysis of the optical elements installed in the beamline, and the beam size measurements performed using double slit interferometry in both horizontal and vertical planes.
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TUPF26	Linear Focal Cherenkov-Ring Camera for Single Shot Observation of Longitudinal Phase Space Distribution for Non-Relativistic Electron Beam	electron, laser, gun, photon	385
	K. Nanbu, H. Hama, F. Hinode, S. Kashiwagi, A. Lueangaramwong, T. Muto, I. Nagasawa, S. Nagasawa, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A test accelerator for the coherent THz source (t-ACTS) has been constructed at Tohoku University, in which the generation of intense coherent THz radiation from sub-picosecond electron bunches will be demonstrated. The final electron bunch length of accelerated beam is mostly dictated by the longitudinal phase space distribution at the exit of electron-gun. Therefore, measurement of Initial electron distribution in the longitudinal phase space produced by an electron gun is crucial for stable production of very short electron bunches, However, measurement of the longitudinal phase space of a relatively lower energy electron beam is especially difficult because space charge effects in drift spaces for measurement system might be strong. A method for measurement of electron energy (or momentum) applying velocity dependence of the opening angle of Cherenkov radiation in the radiator has been proposed for relatively lower energy electrons. Combined use of a streak camera and the “turtle-back” mirror that confines the Cherenkov light onto a linear focal line may allow us to observe the longitudinal phase space distribution directly. Current status of the system development will be reported in this conference.
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TUPD09	Vacuum Improvement of Bunch Shape Monitor for J-PARC Linac	target, high-voltage, electron, linac	430
	A. Miura, Y. Kawane, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan T. Miyao KEK, Ibaraki, Japan
	During the shutdown in summer 2012, we installed three BSMs (Bunch Shape Monitors) at the upstream of the ACS (Annular Coupled Structure Linac) section in order to perform longitudinal matching. ACS cavities were installed in summer 2013 to upgrade the Linac energy from 181 MeV to 400 MeV. Prior to the ACS installation, BSMs were installed and the beam commissioning of the BSMs has been conducted after the summer shutdown in 2012. During the BSM measurements, a problem of the degradation in vacuum conditions was found. One reason for this problem is the dark current resulting in the desorption of absorbed gas molecules. And another reason is the outgas released from materials when the high voltage and RF power are supplied for the electro-static lens and RF deflector, respectively. In order to solve this problem, BSMs were dismounted from the beam line and the off-line baking operations with outgas analysis had been performed to avoid the degradation of the vacuum. As the result of the gas analysis, we found that the outgas contains some heavy hydrocarbons. After these heavy hydrocarbon gaseous were removed and the vacuum level improved for about one order, we completed off-line baking. We will install all three BSMs in at the upstream of the ACS again with the additional vacuum pumps. This paper describes the vacuum degradation of the BSMs, how to conduct the baking operation for BSMs and its results. The improved set-ups of the vacuum are also introduced.
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TUPD16	Development of the Transverse Beam Profile Monitors for the PAL-XFEL	electron, diagnostics, radiation, target	452
	I.Y. Kim, J.Y. Choi, H. Heo, H.-S. Kang, C. Kim, G. Mun, B.G. Oh, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	The PAL-XFEL is an X-ray free electron laser under construnction at the Pohang Accelerator Laboratory (PAL), Korea. In the PAL-XFEL, the electron beam can make coherent optical transition radiation (COTR) due to the microbunching instability in the compressed electron beam. In order to obtain transverse beam profiles without the COTR problem, we are developing scintillating screen monitors (with the geometric suppress method) and wire scanners. In this paper, we report test results at the test facility and progress in the development of the screen monitor and the wire scanner for the PAL-XFEL.
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TUPD23	Real-Time Display System for the Optical Fiber Beam Loss Monitor for the PHIL and ThomX Facilities	beam-losses, radiation, real-time, operation	463
	I. Chaikovska, N. Delerue, A. Variola LAL, Orsay, France
	Fiber monitors are an attractive beam loss diagnostics tool. They are based on the detection of the electromagnetic shower produced by the main beam losses. Cherenkov radiation is produced by the electromagnetic shower charged particles within the multimode fibers attached to the vacuum chamber. It is consequently converted to an electrical signal containing the information about the position and intensity of the beam losses. Therefore, a system based on the fibers installed alongside the whole accelerator together with the signal detection system forms a continuous, real-time Fiber Beam Loss Monitor (FBLM). In this context, the FBLM is a very useful tool for the commissioning and beam alignment. In this article we report on the development of the real-time display system for the FBLM at PHIL (PHotoInjector at LAL, Orsay, France) as a prototype of the beam loss monitor for the ThomX project, the compact Compton based X-ray source under construction in Orsay
	Poster TUPD23 [11.431 MB]
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WEPF03	Upgrade of the Fast Beam Intensity Measurement System for the CERN PS Complex	controls, shielding, proton, synchrotron	525
	D. Belohrad, J.C.A. Allica, M. Andersen, W. Andreazza, G. Favre, N. Favre, L.K. Jensen, L. Lenardon, W. Vollenberg CERN, Geneva, Switzerland
	The CERN Proton Synchrotron complex (CPS) has been operational for over 50 years. During this time the Fast Beam Current Transformers (FBCTs) have only been repaired when they ceased to function, or individually modified to cope with new requests. This strategy resulted in a large variation of designs, making their maintenance difficult and limiting the precision with which comparisons could be made between transformers for the measurement of beam intensity transmission. During the first long shut-down of the CERN LHC and its injectors (LS1) these systems have undergone a major consolidation, with detectors and acquisition electronics upgraded to provide a uniform measurement system throughout the PS complex. This paper discusses the solutions used and analyses the first beam measurement results.
	Poster WEPF03 [7.547 MB]
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WEPD21	BPM Data Correction at SOLEIL	electronics, storage-ring, simulation, synchrotron	684
	N. Hubert, B. Béranger, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France
	In a synchrotron light source like SOLEIL, Beam Position Monitors (BPM) are optimized to have the highest sensitivity for an electron beam passing nearby their mechanical center. Nevertheless, this optimization is done to the detriment of the response linearity when the beam is off-centered for dedicated machine physic studies. To correct the geometric non linearity of the BPM, we have applied an algorithm based on a boundary element method. Moreover the BPM electronics is able to provide position data at a turn by turn rate. Unfortunately the filtering process in this electronics mixes the information from one turn to the neighboring turns. An additional demixing algorithm has been set-up to correct this artefact. The paper reports on performances and limitations of those two algorithms that are used at SOLEIL to correct the BPM data.
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THIXB1	Commissioning of the FLASH2 Electron Beam Diagnostics in Respect to its use at the European XFEL	diagnostics, electronics, undulator, electron	712
	N. Baboi, D. Nölle DESY, Hamburg, Germany
	This report presents the first operation experience of the electron beam diagnostics at FLASH2. FLASH2 is a new undulator line at the FLASH linac at DESY. Most electron beam diagnostics installed, like the beam loss monitors, cavity beam position monitors, toroids, beam halo monitors, have been designed for the European XFEL, and will provide operational experience beforehand. A few systems, as for example the button beam position monitors and the ionization chambers, have been developed for FLASH. The controls use the new MTCA.4 standard. Both linacs, FLASH and the European XFEL, require similar performance of the diagnostics systems. Many beam parameters are similar: bunch charge of 0.1 to 1 nC, pulse repetition frequency of 10 Hz, while others will be more critical at the XFEL than the ones currently used at FLASH, like the bunch frequency of up to 4.5 MHz. versus 1 MHz. The commissioning of FLASH2 and its diagnostics is ongoing. The beam monitors have accompanied the first beam through the linac, fine tuning for some systems is still to be done. The achieved performance will be presented in view of their use at the European XFEL.
	Slides THIXB1 [3.875 MB]
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Paper

Title

Other Keywords

Page

MOPF07

Construction and Operational Performance of a Horizontally Adjustable Beam Profile Monitor at NSLS-II

injection, storage-ring, septum, controls

55

B.N. Kosciuk, A. Blednykh, S. Seletskiy
BNL, Upton, Long Island, New York, USA

The NSLS-II Synchrotron Light Source is a 3 GeV electron storage ring currently in the early stages of commissioning at Brookhaven National Laboratory. In order to observe the electron beam cross section in the injection region, a specially designed, horizontally adjustable beam profile monitor was installed at the downstream end of the injection septum. It allows the profiles of the injected, bumped and single turn beam to be viewed and measured. In this presentation, we discuss the final design, construction challenges, and operational performance of this novel device.

Poster MOPF07 [0.953 MB]

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MOPF16

CERN-SPS Wire Scanner Impedence and Wire Heating Studies

coupling, simulation, electromagnetic-fields, emittance

88

E. Piselli, O.E. Berrig, F. Caspers, B. Dehning, J. Emery, M. Hamani, J. Kuczerowski, B. Salvant, R.S. Sautier, R. Veness, C. Vuitton, C. Zannini
CERN, Geneva, Switzerland

This article describes a study performed on one of the SPS vertical rotational wire scanners in order to investigate the breakage of the wire, which occurred on several occasions during the last year of operation. The thermionic emission current of the wire was measured to evaluate temperature changes, and was observed to rise significantly as the wire approached the ultimate LHC beam in the SPS, indicating the possibility of strong coupling between the beam’s electromagnetic field and the wire. Different laboratory measurements, complemented by CST Microwave Studio simulations, have therefore been performed to try and understand the RF modes responsible for this heating. These results are presented here, along with the subsequent modifications adopted on all of the operational SPS wire scanners.

Poster MOPF16 [0.747 MB]

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MOPF19

Design of a Profile Monitor with 12 Inches of Actuation for FRIB

alignment, diagnostics, interface, feedback

97

S. Rodriguez Esparza, G. Kiupel, I.N. Nesterenko
FRIB, East Lansing, Michigan, USA

Funding: FACILITY FOR RARE ISOTOPE BEAMS
Actuated diagnostics present additional challenges that static diagnostics devices do not such as alignment, stability, and incorporating an appropriate drive mechanism. These challenges become even more apparent as the actuaded length increases. At the Facility for Rare Isotope Beams (FRIB) we plan on using a number of actuated diagnostics devices including a Profile Monitor (AKA: Wire Scanner) with 12 inches of actuation. The Profile Monitor uses tungsten wires to traverse the beam pipe aperture to measure the beam intensity with respect to it’s location in the X-Y plane. This paper will detail the design of the 12 inch Profile Monitor and how it is able to overcome the stability, alignment, and drive issues that come with the 12 inches of actuation.

Poster MOPF19 [1.128 MB]

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MOPF31

Overview of Beam Instrumentation Activities for SwissFEL

electron, radiation, undulator, pick-up

119

R. Ischebeck, R. Abela, F. Ardana-Lamas, V.R. Arsov, R. Baldinger, H.-H. Braun, M. Calvi, R. Ditter, C. Erny, F. Frei, R. Ganter, I. Gorgisyan, C.P. Hauri, S. Hunziker, P.N. Juranic, B. Keil, W. Koprek, R. Kramert, D. Llorente Sancho, F. Löhl, F. Marcellini, G. Marinkovic, B. Monoszlai, G.L. Orlandi, C. Ozkan, L. Patthey, M. Pedrozzi, P. Pollet, M. Radovic, L. Rivkin, M. Roggli, M. Rohrer, V. Schlott, A.G. Stepanov, J. Stettler
PSI, Villigen PSI, Switzerland
F. Ardana-Lamas, I. Gorgisyan, C.P. Hauri, L. Rivkin
EPFL, Lausanne, Switzerland
P. Peier
DESY, Hamburg, Germany

SwissFEL will provide users with brilliant X-ray pulses in 2017. A comprehensive suite of diagnostics is needed for the initial commissioning, for changes to the operating point, and for feedbacks. The development of instrumentation for SwissFEL is well underway, and solutions have been identified for most diagnostics systems. I will present here an overview of the instrumentation for SwissFEL, and give details on some recent developments.

Poster MOPF31 [4.418 MB]

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TUCYB3

SwissFEL Beam Profile Monitor

radiation, electron, laser, detector

259

R. Ischebeck, E. Prat, V. Schlott, V.G. Thominet
PSI, Villigen PSI, Switzerland
P. Krejcik, H. Loos
SLAC, Menlo Park, California, USA
M. Yan
DESY, Hamburg, Germany

We have developed a beam profile monitor that allows us to measure two-dimensional electron beam profiles for highly compressed electron bunches. Such bunches have plagued profile measurements in optical transition radiation monitors in the past, because coherent radiation entering the optical system has invalidated the images and even destroyed cameras. The present design makes use of a scintillating crystal, and directs coherent transition radiation away from the optical axis by careful choice of the angle. When observing Snell's law of refraction as well as the Scheimpflug imaging condition, a resolution better than the thickness of the scintillator can be achieved. We will present measurements performed at the SwissFEL Injector Test Facility and at the Linac Coherent Light Source. The high resolution and excellent sensitivity of this monitor make it ideal for installation in SwissFEL.

Slides TUCYB3 [42.624 MB]

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TUCZB3

A Quantum Gas Jet for Non-Invasive Beam Profile Measurement

ion, focusing, photon, electron

284

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

A novel instrument for accelerator beam diagnostics is being developed by using De Broglie-wave focusing to create an ultra-thin neutral gas jet. Scanning the gas jet across a particle beam while measuring the interaction products, the beam profile can be measured. Such a jet scanner will provide an invaluable diagnostic tool in beams which are too intense for the use of wire scanners, such as the proposed CLIC Drive Beam. In order to create a sufficiently thin jet, a focusing element working on the DeBroglie wavelength of the Helium atom has been designed. Following the principles of the Photon Sieve, we have constructed an Atomic Sieve consisting of 5230 nano-holes etched into a thin film of silicon nitride. When a quasi-monochromatic Helium jet is incident on the sieve, an interference pattern with a single central maximum is created. The stream of Helium atoms passing through this central maximum is much narrower than a conventional gas jet. The first experiences with this device are presented here, along with plans for further tests.

Slides TUCZB3 [13.880 MB]

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TUPF03

Overview of the Geometrical Non-Linear Effects of Button BPMs and Methodology for Their Efficient Suppression

pick-up, simulation, coupling, storage-ring

298

A.A. Nosych, U. Iriso, A. Olmos
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
M. Wendt
CERN, Geneva, Switzerland

This paper describes an overview of the geometric non-linear effects common to beam position monitors (BPMs) installed in the accelerators and a methodology to correct for these effects. A typical characteristic curve of a pick-up is linear within a limited range from the BPM origin. At larger offsets the non-linearity of the curve is more pronounced and gets worse if the button diameter is small with respect to the beam pipe diameter. The general real-time linearization methods usually utilize linear correction combined with a simplistic polynomial, which may lead to inaccuracies in their limited application. We have developed a more rigorous methodology to suppress the non-linear effects of the BPMs through electromagnetic (EM) simulations and 2D fitting approximations. The focus is mainly on standard button pick-ups for the electron (ALBA) and proton machines (LHC).

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TUPF04

Numerical Calculations for the FAIR Proton Linac BPMs

linac, simulation, proton, pick-up

303

C.S. Simon
CEA/DSM/IRFU, France
M.H. Almalki, P. Forck, W. Kaufmann, T. Sieber
GSI, Darmstadt, Germany
V. Bellego
CEA/IRFU, Gif-sur-Yvette, France

Fourteen Beam Position Monitors (BPMs) will be installed along the FAIR Proton LINAC. These monitors will be used to determine the beam position, the relative beam current and the mean beam energy by time of flight (TOF). A capacitive button type pickup was chosen for its easy mechanical realization and for the short insertion length which is important for the four BPMs locations of the inter-tank sections between the CH-cavities. Depending on the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, limited space for installation and a 30 mm or 50 mm beam pipe aperture. This paper reports wake field numerical simulations performed by the code CST PARTICLE STUDIO to design and characterize the BPMs. Time of response of monitors are presented and results of calculations for various pickup-geometries are discussed taking into account different beam velocities.

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TUPF05

Production Process for the European XFEL Re-Entrant Cavity BPM

cavity, cryomodule, quadrupole, controls

307

C.S. Simon, P. Carbonnier, P. Contrepois, F. Éozénou, Y. Gasser, O. Napoly, J. Novo, C. Servouin
CEA/DSM/IRFU, France
C. Boulch, Y. Gasser
CEA/IRFU, Gif-sur-Yvette, France
P. Daniel-Thomas, F. Gouit
CEA, Gif-sur-Yvette, France
J. Kruse, D. Nölle, M. Schalwat, S. Vilcins
DESY, Hamburg, Germany
N. Rouvière
IPN, Orsay, France

As In-Kind contributor to the E-XFEL project, CEA is committed to the procurement of around one third (31) cold beam position monitors (BPM) of the re-entrant RF cavities type and to the assembly on the Saclay site of the 101 cryomodules of the superconducting linac. Each cryomodule is equipped with a beam position monitor connected to a quadrupole at the high-energy end of the cavity string. The industrial process of those BPMs, used in an ultra-clean environment at cryogenic temperature, includes several steps and involves a quality control in collaboration with industrial partners. This paper describes the different steps of the re-entrant cavity BPM fabrication process: machining, copper coating, thermal treatment, EB welding, cleaning and mounting in clean room on the quadrupole. Problems encountered and the lessons learnt will be also reported.

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TUPF11

Mechanical Design of Cryogenic Vacuum Feedthroughs for X-FEL Button BPMs

cryogenics, simulation, project-management, operation

332

S. Vilcins, D. Lipka
DESY, Hamburg, Germany

The European XFEL is a 4th generation synchrotron radiation source, currently under construction in Hamburg. Based on different Free-Electron Laser and spontaneous sources and driven by a superconducting accelerator, it will be able to provide several user stations with photons simultaneously. Due to the superconducting technology in the accelerators modules many components have to operate at liquid helium temperature. This poster will concentrate on high frequency ultra high vacuum feedthrough used for the beam position monitors of the cryogenic accelerator modules. Main emphasis will be put on the design of these feedthroughs, their material composition and the production process. The capability to be used under these very special conditions was investigated with FEM simulations, as well as with a test procedure. The results of these simulations will be presented; the tests and their results will be explained in detail.

Poster TUPF11 [0.407 MB]

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TUPF14

Newly Developed 6mm Buttons for the BPMs in the ESRF Low-Emittance-Ring

coupling, factory, simulation, operation

346

K.B. Scheidt
ESRF, Grenoble, France

For the small beam pipe of the BPMs in the LE-ring a development of 6mm button-UHV-feedthroughs was launched and has resulted in the delivery of a total of 27 prototypes from both the Kyocera and the PMB-ALCEN companies. These buttons are flat, without skirt, with a central pin of Molybdenum ending in a male SMA connector. Among these prototype units are versions with Copper, Steel and Molybdenum material for the button itself, with the aim of assessing possible different heatload issues. All design considerations, that are compatible with a further button reduction to 4mm, will be presented next to issues of costs, mechanical tolerances and feasibility.

Poster TUPF14 [1.420 MB]

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TUPF23

Beam Size Measurements using Synchrotron Radiation Interferometry at ALBA

radiation, extraction, synchrotron, synchrotron-radiation

374

L. Torino, U. Iriso
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
T.M. Mitsuhashi
KEK, Ibaraki, Japan

First tests to measure the transverse beam size using interferometry at ALBA showed that the measurement reliability was limited by the inhomogeneous light wavefront arriving at the double slit system. For this reason, the optical components guiding the synchrotron radiation have been exchanged, and detailed quality checks have been carried out using techniques like the Fizeau interferometry or Hartmann mask tests. We report the results of the analysis of the optical elements installed in the beamline, and the beam size measurements performed using double slit interferometry in both horizontal and vertical planes.

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TUPF26

Linear Focal Cherenkov-Ring Camera for Single Shot Observation of Longitudinal Phase Space Distribution for Non-Relativistic Electron Beam

electron, laser, gun, photon

385

K. Nanbu, H. Hama, F. Hinode, S. Kashiwagi, A. Lueangaramwong, T. Muto, I. Nagasawa, S. Nagasawa, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test accelerator for the coherent THz source (t-ACTS) has been constructed at Tohoku University, in which the generation of intense coherent THz radiation from sub-picosecond electron bunches will be demonstrated. The final electron bunch length of accelerated beam is mostly dictated by the longitudinal phase space distribution at the exit of electron-gun. Therefore, measurement of Initial electron distribution in the longitudinal phase space produced by an electron gun is crucial for stable production of very short electron bunches, However, measurement of the longitudinal phase space of a relatively lower energy electron beam is especially difficult because space charge effects in drift spaces for measurement system might be strong. A method for measurement of electron energy (or momentum) applying velocity dependence of the opening angle of Cherenkov radiation in the radiator has been proposed for relatively lower energy electrons. Combined use of a streak camera and the “turtle-back” mirror that confines the Cherenkov light onto a linear focal line may allow us to observe the longitudinal phase space distribution directly. Current status of the system development will be reported in this conference.

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TUPD09

Vacuum Improvement of Bunch Shape Monitor for J-PARC Linac

target, high-voltage, electron, linac

430

A. Miura, Y. Kawane, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
T. Miyao
KEK, Ibaraki, Japan

During the shutdown in summer 2012, we installed three BSMs (Bunch Shape Monitors) at the upstream of the ACS (Annular Coupled Structure Linac) section in order to perform longitudinal matching. ACS cavities were installed in summer 2013 to upgrade the Linac energy from 181 MeV to 400 MeV. Prior to the ACS installation, BSMs were installed and the beam commissioning of the BSMs has been conducted after the summer shutdown in 2012. During the BSM measurements, a problem of the degradation in vacuum conditions was found. One reason for this problem is the dark current resulting in the desorption of absorbed gas molecules. And another reason is the outgas released from materials when the high voltage and RF power are supplied for the electro-static lens and RF deflector, respectively. In order to solve this problem, BSMs were dismounted from the beam line and the off-line baking operations with outgas analysis had been performed to avoid the degradation of the vacuum. As the result of the gas analysis, we found that the outgas contains some heavy hydrocarbons. After these heavy hydrocarbon gaseous were removed and the vacuum level improved for about one order, we completed off-line baking. We will install all three BSMs in at the upstream of the ACS again with the additional vacuum pumps. This paper describes the vacuum degradation of the BSMs, how to conduct the baking operation for BSMs and its results. The improved set-ups of the vacuum are also introduced.

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TUPD16

Development of the Transverse Beam Profile Monitors for the PAL-XFEL

electron, diagnostics, radiation, target

452

I.Y. Kim, J.Y. Choi, H. Heo, H.-S. Kang, C. Kim, G. Mun, B.G. Oh, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

The PAL-XFEL is an X-ray free electron laser under construnction at the Pohang Accelerator Laboratory (PAL), Korea. In the PAL-XFEL, the electron beam can make coherent optical transition radiation (COTR) due to the microbunching instability in the compressed electron beam. In order to obtain transverse beam profiles without the COTR problem, we are developing scintillating screen monitors (with the geometric suppress method) and wire scanners. In this paper, we report test results at the test facility and progress in the development of the screen monitor and the wire scanner for the PAL-XFEL.

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TUPD23

Real-Time Display System for the Optical Fiber Beam Loss Monitor for the PHIL and ThomX Facilities

beam-losses, radiation, real-time, operation

463

I. Chaikovska, N. Delerue, A. Variola
LAL, Orsay, France

Fiber monitors are an attractive beam loss diagnostics tool. They are based on the detection of the electromagnetic shower produced by the main beam losses. Cherenkov radiation is produced by the electromagnetic shower charged particles within the multimode fibers attached to the vacuum chamber. It is consequently converted to an electrical signal containing the information about the position and intensity of the beam losses. Therefore, a system based on the fibers installed alongside the whole accelerator together with the signal detection system forms a continuous, real-time Fiber Beam Loss Monitor (FBLM). In this context, the FBLM is a very useful tool for the commissioning and beam alignment. In this article we report on the development of the real-time display system for the FBLM at PHIL (PHotoInjector at LAL, Orsay, France) as a prototype of the beam loss monitor for the ThomX project, the compact Compton based X-ray source under construction in Orsay

Poster TUPD23 [11.431 MB]

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WEPF03

Upgrade of the Fast Beam Intensity Measurement System for the CERN PS Complex

controls, shielding, proton, synchrotron

525

D. Belohrad, J.C.A. Allica, M. Andersen, W. Andreazza, G. Favre, N. Favre, L.K. Jensen, L. Lenardon, W. Vollenberg
CERN, Geneva, Switzerland

The CERN Proton Synchrotron complex (CPS) has been operational for over 50 years. During this time the Fast Beam Current Transformers (FBCTs) have only been repaired when they ceased to function, or individually modified to cope with new requests. This strategy resulted in a large variation of designs, making their maintenance difficult and limiting the precision with which comparisons could be made between transformers for the measurement of beam intensity transmission. During the first long shut-down of the CERN LHC and its injectors (LS1) these systems have undergone a major consolidation, with detectors and acquisition electronics upgraded to provide a uniform measurement system throughout the PS complex. This paper discusses the solutions used and analyses the first beam measurement results.

Poster WEPF03 [7.547 MB]

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WEPD21

BPM Data Correction at SOLEIL

electronics, storage-ring, simulation, synchrotron

684

N. Hubert, B. Béranger, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

In a synchrotron light source like SOLEIL, Beam Position Monitors (BPM) are optimized to have the highest sensitivity for an electron beam passing nearby their mechanical center. Nevertheless, this optimization is done to the detriment of the response linearity when the beam is off-centered for dedicated machine physic studies. To correct the geometric non linearity of the BPM, we have applied an algorithm based on a boundary element method. Moreover the BPM electronics is able to provide position data at a turn by turn rate. Unfortunately the filtering process in this electronics mixes the information from one turn to the neighboring turns. An additional demixing algorithm has been set-up to correct this artefact. The paper reports on performances and limitations of those two algorithms that are used at SOLEIL to correct the BPM data.

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THIXB1

Commissioning of the FLASH2 Electron Beam Diagnostics in Respect to its use at the European XFEL

diagnostics, electronics, undulator, electron

712

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

This report presents the first operation experience of the electron beam diagnostics at FLASH2. FLASH2 is a new undulator line at the FLASH linac at DESY. Most electron beam diagnostics installed, like the beam loss monitors, cavity beam position monitors, toroids, beam halo monitors, have been designed for the European XFEL, and will provide operational experience beforehand. A few systems, as for example the button beam position monitors and the ionization chambers, have been developed for FLASH. The controls use the new MTCA.4 standard. Both linacs, FLASH and the European XFEL, require similar performance of the diagnostics systems. Many beam parameters are similar: bunch charge of 0.1 to 1 nC, pulse repetition frequency of 10 Hz, while others will be more critical at the XFEL than the ones currently used at FLASH, like the bunch frequency of up to 4.5 MHz. versus 1 MHz. The commissioning of FLASH2 and its diagnostics is ongoing. The beam monitors have accompanied the first beam through the linac, fine tuning for some systems is still to be done. The achieved performance will be presented in view of their use at the European XFEL.

Slides THIXB1 [3.875 MB]

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