IBIC2013 - List of Keywords (pick-up)

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

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

MOPC09	Development of the Sirius RF BPM Electronics	BPM, controls, storage-ring, simulation	63
	D.O. Tavares, R.A. Baron, F.H. Cardoso, S.R. Marques, J.L.B. Neto, L.M. Russo LNLS, Campinas, Brazil A.P. Byszuk, G. Kasprowicz, A.J. Wojenski Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	A BPM system has been developed for the new low emmitance 3 GeV Brazilian synchrotron light source, Sirius. The Sirius BPM electronics is a modular system based on a PICMG(R) MicroTCA.4 platform using ADC mezzanine cards in ANSI/VITA 57.1 FMC form factor and standalone RF front-end boards. It has been designed under the CERN Open Hardware License (OHL) in a collaboration between Brazilian Synchrotron Light Laboratory (LNLS) and Warsaw University of Technology (WUT). This paper presents: i) overall architecture of the BPM system; ii) performance evaluation of the first prototype of the BPM electronics comprehending beam current, filling pattern and temperature dependencies as well as resolution vs. beam current; and iii) preliminary results with beam at LNLS's UVX storage ring.
	Poster MOPC09 [1.451 MB]

MOPC14	Beam Position Monitors R&D for keV Ion Beams	simulation, BPM, antiproton, multipole	78
	S. Naveed, A.A. Nosych, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom S. Naveed, A.A. Nosych, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A.A. Nosych, L. Søby CERN, Geneva, Switzerland
	Funding: Work supported by the EU within the DITANET and oPAC projects under contracts 215080 and 289485, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1. Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams on the examples of the USR and ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values and describe an experimental setup realized at the Cockcroft Institute for BPM callibration. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably.

MOPC19	Status of the Beam Position Monitors for LIPAc	BPM, simulation, beam-position, linac	93
	I. Podadera, F.M. De Aragon, A. Guirao, D. Jimenez, A. Lara, L.M. Martinez, J. Molla CIEMAT, Madrid, Spain
	Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC10-A-000441 and AIC-A-2011-0654. The LIPAc 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. Several types of Beam Position Monitors BPM’s- are placed in each section of the accelerator to ensure a good beam transport and minimize beam losses. Prototypes of almost all the BPM’s have been already fabricated. Acceptance tests have been carried out on each device. The output of the vacuum leak tests and electrical tests will be analyzed in this contribution. In addition, the test bench to characterize the BPM’s has been upgraded and validated using some prototypes in order to obtain a better global measurement accuracy of the electrical center offset. The test bench can be used to crosscheck the simulations with the real response of each BPM. The result of the comparison will be discussed in detail.

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

MOPC26	Optimization of Bunch-to-Bunch Isolation in Instability Feedback Systems	coupling, feedback, kicker, FIR	116
	D. Teytelman Private Address, San Jose, USA
	Bunch-by-bunch feedback formalism is a powerful tool for combating coupled-bunch instabilities in circular accelerators. Imperfections in the analog front and back ends lead to coupling between neighboring bunches. Such coupling limits system performance in both feedback and diagnostic capacities. In this paper, techniques for optimizing bunch-to-bunch isolation within the system will be presented. A new method for improving the performance of the existing systems will be described. The novel approach uses a "shaper" filter in the digital signal processor to compensate for the imperfect response of the power amplifier and kicker combination. An objective optimization method to derive the optimal back end configuration will be presented and illustrated with measurements from several accelerators.
	Poster MOPC26 [0.851 MB]

MOPC42	Novel Pickup for Bunch Arrival Time Monitor	LEFT, transverse, simulation, laser	170
	A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	For an optical-modulator-based BAM, main parameter of the pickup output signal is slope steepness. We suggest a novel pickup with flat thin electrodes in a transverse gap. Increasing the electrode width makes the steepness greater in the same extent as the signal increases. For a given width, reducing the electrode thickness allows to reach ultimate steepness. Wave processes in the pickup were investigated on a large scale model, using the technique described in . The DESY 40GHz button pickup was used as a reference. It is shown that steepness of the flat electrode pickup can be achieved two times greater. It is also shown that a BAM electrode pickup has a remarkable feature: the steepness does not depend on electrode sizes, if the ratio w/G (a flat electrode pickup, the width and gap length) or d/D (a button pickup, the diameters) is kept constant. This makes pickup bandwidth that is of the order of c over 2G or 2D, a free parameter. For flat electrode pickup, the steepness can be kept as high with transition to a more practical bandwidth 20GHz. The investigation results are the base for a final pickup optimisation using electrodynamic simulation. A. Kalinin, “Pickup Electrode Electrodynamics Investigation”, WEPC26, this conference
	Poster MOPC42 [0.549 MB]

TUBL3	A Multiband-Instability-Monitor for High-Frequency Intra-Bunch Beam Diagnostics	LHC, CERN, SPS, synchrotron	327
	R.J. Steinhagen CERN, Geneva, Switzerland M.J. Boland, T.G. Lucas The University of Melbourne, Melbourne, Australia
	To provide the best possible luminosity, even higher beam intensities are needed in the Large Hadron Collider (LHC) and in its injector chain. This is fundamentally limited by self-amplifying beam instabilities, intrinsic to unavoidable imperfections in accelerators. Traditionally, intra-bunch or head-tail particle motion is measured using fast digitizers, which even using state-of-the-art technology are limited in their effective intra-bunch position resolution to few tens of um in the multi-GHz regime. Oscillations at this scale cause partial or total loss of the beam due to the tight transverse constraints imposed by the LHC collimation system. To improve on the present signal processing, a prototype system has been designed, constructed and tested at the CERN Super-Proton-Synchrotron (SPS) and later on LHC. The system splits the signal into multiple equally-spaced narrow frequency bands that are processed and analysed in parallel. Working with narrow-band signals in frequency-domain permits the use of much higher resolution analogue-to-digital-converters that can be used to resolve nm-scale particle motion already during the onset of instabilities.
	Slides TUBL3 [3.165 MB]

TUPC14	Development of a Low-Beta Button BPM for PXIE Project	BPM, simulation, beam-position, longitudinal	392
	A. Lunin, N. Eddy, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev Fermilab, Batavia, USA
	The button BPM is under development for a low beta section of the Project X Injector Experiment (PXIE) at Fermilab. The presented paper includes an analytical estimation of the BPM performance as well a direct wakefield simulation with CST Particle Studio (on a hexahedral mesh). In addition we present a novel approach of a low beta beam interaction with BPM electrodes realized with ANSYS HFSS TD-solver on unstructured tetrahedral mesh. Both methods show a good agreement of BPM output signals for various beam parameters. Finally we describe the signal processing scheme and the electronics we are going to use.
	Poster TUPC14 [1.051 MB]

TUPC19	First Beam Tests of a Prototype Cavity Beam Position Monitor for the CLIC Main Beam	single-bunch, beam-position, BPM, dipole	411
	F.J. Cullinan, S.T. Boogert, A. Lyapin, J.R. Towler JAI, Egham, Surrey, United Kingdom W. Farabolini, T. Lefèvre, L. Søby, M. Wendt CERN, Geneva, Switzerland
	Beam position monitors (BPMs) throughout the CLIC (Compact Linear Collider) main linac and beam delivery system must routinely operate at 50 nm resolution and be able to make multiple position measurements within a single 156 ns long bunch train. A prototype cavity beam position monitor, designed to demonstrate this performance, has been tested on the probe beamline of CTF3 (the CLIC Test Facility). Sensitivity measurements of the dipole mode position cavity and of the monopole mode reference cavity have been made. The characteristics of signals from short and long bunch trains and the dominant systematic effects have also been studied.

TUPC20	Technologies and R&D for a High Resolution Cavity BPM for the CLIC Main Beam	BPM, CLIC, CTF3, coupling	415
	J.R. Towler, T. Lefèvre, L. Søby, M. Wendt CERN, Geneva, Switzerland S.T. Boogert, F.J. Cullinan, A. Lyapin JAI, Egham, Surrey, United Kingdom
	The Main Beam (MB) LINAC of the Compact Linear Collider (CLIC) requires a beam orbit measurement system with a high spatial (50 nm) and high temporal (50 ns) resolution to resolve the beam position within the 156 ns long bunch train, traveling on an energy-chirped, minimum dispersive trajectory. A 15 GHz prototype cavity BPM has been commissioned in the probe beam-line of the CTF3 CLIC Test Facility. The performance and technical details of this prototype installation are discussed in this paper, including the 15 GHz analog down-converter, the data acquisition and the control electronics and software. An R&D outlook is given for the next steps, which requires a system of 3 cavity BPMs to investigate the full resolution potential.

TUPC25	Design of the SwissFEL BPM System	BPM, XFEL, undulator, linac	427
	B. Keil, R. Baldinger, R. Ditter, W. Koprek, R. Kramert, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler, D.M. Treyer PSI, Villigen PSI, Switzerland
	SwissFEL is a Free Electron Laser (FEL) facility being constructed at PSI, based on a 5.8GeV normally conducting main linac. A photocathode gun will generate two bunches with 28ns spacing at 100Hz repetition rate, with a nominal charge range of 10-200pC. A fast beam distribution kicker will allow to distribute one bunch to a soft X-ray undulator line and the other bunch to a 0.1nm hard X-ray undulator line. The SwissFEL electron beam position monitor (BPM) system will employ three different types of dual-resonator cavity BPMs, since the accelerator has three different beam pipe apertures. In the injector and main linac (38mm and 16mm aperture), 3.3GHz cavity BPMs will be used, where a low Q of ~40 was chosen to minimize crosstalk of the two bunches. In the undulators that just have single bunches and 8mm BPM aperture, a higher Q will be chosen. This paper reports on the development status of the SwissFEL BPM system. Synergies as well as differences to the E-XFEL BPM system* will also be highlighted. * F. Marcellini et al., "Design of Cavity BPM Pickups For SwissFEL", Proc. IBIC'12, Tsukuba, Japan, 2012. ** B. Keil et al., "The European XFEL BPM System", Proc. IPAC'10, Kyoto, Japan, 2010.
	Poster TUPC25 [1.074 MB]

TUPC29	Grounded Coplanar Waveguide Transmission Lines as Pickups for Beam Position Monitoring in Particle Accelerators	XFEL, simulation, beam-position, coupling	438
	A. Penirschke, A. Angelovski, R. Jakoby TU Darmstadt, Darmstadt, Germany C. Gerth, U. Mavrič, D. Nölle, C. Sydlo, S. Vilcins DESY, Hamburg, Germany
	Funding: The work was supported by the MSK group at DESY Hamburg. The authors would like to thank the CST AG for providing the CST Software Package. Energy beam position monitors (EBPM) based on grounded co-planar waveguide (GCPW) transmission lines have been designed for installation in the dispersive sections of the bunch compressor chicanes at the European XFEL. In combination with beam position monitors at the entrance and exit of the bunch compressor chicanes, measurements of the beam energy with single bunch resolution are feasible. The EBPM consists of transversely mounted stripline pickups in a rectangular beam pipe section. The signal detection for the measurement of the phases of the pulses at each end of the pickups is based on the standard down-conversion and phase detection scheme used for the low-level RF-system. A measurement resolution within the lower micrometer range can be achieved for input signal reflections at the pickup of less than -25 dB at 3 GHz. In this paper, simulation results of a novel pickup geometry utilized with GCPW pickup structures and optimized transitions to perpendicular mounted coaxial connectors are presented. The simulation results exhibit small reflection coefficients with reflected signal components having less than 2% of the peak voltage signal.

TUPC35	Upgrade of the Read-out Electronics for the Energy Beam Position Monitors at FLASH and European XFEL	XFEL, beam-position, DESY, SNR	454
	U. Mavrič, C. Gerth, H. Schlarb DESY, Hamburg, Germany A. Piotrowski TUL-DMCS, Łódź, Poland
	The dispersive sections of magnetic bunch compressor chicanes at free-electron lasers are excellent candidates for beam energy measurements. In the rectangular beamline sections of the bunch compressors at FLASH, energy beam position monitors (EBPM) with transversely mounted stripline pickups are installed. In this paper, we present the upgrade of the read-out electronics for signal detection of the EBPM installed at FLASH. The system is based on the MTCA.4 standard and reuses already available MTCA.4 compliant modules. This is also true for gateware and software development which fits into standard MTCA.4 framework development. The performance of the instrument was studied at FLASH during user operation and the results are presented.

TUPF27	An Ultra Low-Noise AC Beam Transformer and Digital Signal Processing System for CERN’s ELENA Ring	CERN, diagnostics, longitudinal, extraction	571
	M.E. Angoletta, C. Carli, F. Caspers, S. Federmann, J.C. Molendijk, F. Pedersen, J. Sanchez-Quesada CERN, Geneva, Switzerland
	CERN’s Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator. Essential longitudinal diagnostics required for commissioning and operation include the intensity measurement for bunched and debunched beams and the measurement of Dp/p for debunched beams to assess the electron cooling performance. The beam phase information is also needed by the low-level RF system. The baseline system for providing the required beam parameters and signals is based upon two ultra-low-noise AC beam transformers and associated digital signal processing. The AC beam transformers cover different frequency regions and are an adaptation to the ELENA layout of those used in the AD. Two AC beam transformers will also be installed in the extraction lines to provide beam intensity and bunch shape measurements. The digital signal processing will be carried out with the leading-edge hardware family used for ELENA’s low-level RF system. The paper provides an overview of the beam transformer and head amplifier, as well as of the associated digital signal processing.

TUPF31	Intensity Control in GANIL’s Experimental Rooms	diagnostics, controls, simulation, instrumentation	587
	C. Courtois, C. Doutresssoulles, B. Ducoudret, C. Jamet, W. Le Coz, G. Ledu, C. Potier de courcy GANIL, Caen, France
	The safety re-examination of existing GANIL facilities requires the implementation of a safety system which makes a control of beam intensities sent in the experimental rooms possible. The aim is to demonstrate that beam intensities are below the authorized limits. The required characteristics should enable the measurement, by a non-interceptive method, of beam intensities from 5 nA to 5μA with a maximum uncertainty of 5%, independently of the frequency and the beam energy. After a comparative study, two types of high frequency diagnostics were selected, the capacitive peak-up and the Fast current transformer. This paper presents the signal simulations from diagnostics with different beam energies, the uncertainty calculations and the results of the first tests with beam.
	Poster TUPF31 [2.086 MB]

TUPF32	A Cryogenic Current Comparator for FAIR with Improved Resolution	cryogenics, DESY, shielding, longitudinal	590
	R. Geithner, W. Vodel HIJ, Jena, Germany R. Geithner, R. Neubert, P. Seidel FSU Jena, Jena, Germany F. Kurian, H. Reeg, M. Schwickert GSI, Darmstadt, Germany
	A Cryogenic Current Comparator is a highly sensitive tool for the non-destructive online monitoring of continuous as well as bunched beams of very low intensities. The noise-limited current resolution of such a device depends on the ferromagnetic material embedded in the pickup coil of the CCC. Therefore, the main focus of research was on the low temperature properties of ferromagnetic core materials. In this contribution we present first results of the completed Cryogenic Current Comparator for FAIR working in a laboratory environment, regarding the improvements in resolution due to the use of suitable ferromagnetic core materials.
	Poster TUPF32 [3.868 MB]

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

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

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

WEPC12	Evaluation of Strip-line Pick-up System for the SPS Wideband Transverse Feedback System	SPS, feedback, transverse, coupling	690
	G. Kotzian, W. Höfle, R.J. Steinhagen, D. Valuch, U. Wehrle CERN, Geneva, Switzerland
	The proposed SPS Wideband Transverse Feedback system requires a wide-band pick-up system to be able to detect intra-bunch motion within the SPS proton bunches, captured and accelerated in a 200 MHz bucket. We present the electro-magnetic design of transverse beam position pick-up options optimised for installation in the SPS and evaluate their performance reach with respect to direct time domain sampling of the intra-bunch motion. The analysis also discusses the achieved subsystem responses of the associated cabling with new low dispersion smooth wall cables, wide-band generation of intensity and position signals by means of 180 degree RF hybrids as well as passive techniques to electronically suppress the beam offset signal, needed to optimise the dynamic range and position resolution of the planned digital intra-bunch feedback system.

WEPC16	The Design of BPM Electronic System for CSNS RCS	BPM, extraction, injection, beam-position	706
	W. Lu, H.Y. Sheng, X.C. Tian, J.W. Zhao, Y.B. Zhao IHEP, Bejing, People's Republic of China
	A Beam Position Monitor (BPM) system has been designed for the Rapid Cycling Synchrotron (RCS) at the China Spallation Neutron Source (CSNS) to acquire beam position information. This article introduces the design and implementation of the BPM electronic system. The challenge of designing the BPM electronics is to acquire and process the signal with large dynamic range (5.8mV~32V) and changing width (80ns to 500ns). The analog circuit described in this paper, which is constructed of a single-stage operational amplifier and an analog switch, can cover the input signal with large dynamic range. Because of the minimum bunch length (80ns) and the requirement of position resolution, a 14 bit 250MHz ADC is adopted to digitize the signal. Besides, for BPM system, the demand of an accurate real-time position monitoring is mandatory. The algorithm developed in an FPGA is able to make Bunch-by-Bunch position calculation and Closed Orbit position calculation in real time. Also, some preliminary test results will be presented and discussed, which show that the resolution of Bunch-by-Bunch position is 0.8mm when the input signal is 5.8mV and the resolution of Closed Orbit position is 50um.
	Poster WEPC16 [0.937 MB]

WEPC17	Design and Simulation of Beam Position Monitor for the CADS Injector I Proton Linac	BPM, simulation, linac, impedance	710
	Y.F. Sui, J.S. Cao, H.Z. Ma, Q. Ye, J. Yue IHEP, People's Republic of China
	Funding: Work supported by the National Natural Science Foundation of China (NO. 11205172) Beam Position Monitors (BPM) based on both capacitive and stripline pick-ups are designed for the China Accelerator Driven Subcritical system (C-ADS) Injector I proton LINAC. The BPM will be installed to measure the transverse beam position in the LINAC, of which the beam parameters are listed as current 10mA, energy 10MeV and the repetition frequency 325MHz. This contribution presents the status of the BPM design development and focuses on the design of the pick-ups and CST Particle Studio simulation results, including impedance, sensitivity, time domain, frequency domain response, etc. The main goal of the simulation is optimization of the mechanical design.

WEPC21	Design and Beam Test Results of Button BPMs for the European XFEL	BPM, XFEL, controls, DESY	723
	D.M. Treyer, R. Baldinger, R. Ditter, B. Keil, W. Koprek, G. Marinkovic, M. Roggli PSI, Villigen PSI, Switzerland D. Lipka, D. Nölle, S. Vilcins DESY, Hamburg, Germany
	Funding: Swiss State Secretariat for Education, Research and Innovation The European X-ray Free Electron Laser (E-XFEL) will use a total ~300 button BPMs along the whole accelerator, as well as 160 cavity BPMs. The pickups for the button BPMs have been designed by DESY, whereas the electronics has been developed by PSI. This paper gives an overview of the button BPM system, with focus on the RF front end electronics, signal processing, and overall system performance. Measurement results achieved with prototypes installed at FLASH/DESY and at the SwissFEL Injector Test Facility (SITF) are presented. The position noise obtained with button pickups in a 40.5 mm aperture beam pipe is as low as ~11 um at 20 pC bunch charge.
	Poster WEPC21 [1.595 MB]

WEPC26	Pickup Electrode Electrodynamics Investigation	LEFT, transverse, impedance, vacuum	742
	A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Waves induced in a pickup by beam were investigated on a large scale model, using 10ps step in coaxial line as beam, and a differentiating capacitive probe. The probe signal was observed at 20GHz oscilloscope. In each of the front and rear transverse gaps between pickup electrode and wall (button pickup), a shorter-than-gap bunch excites a ‘plain-wave’ packet which length is of the order of gap length over c. Two packets are spaced by electrode length over c. The packets propagate along the electrode to a coaxial connector. At this low impedance common point each of the packets partially reflects back and partially passes into the opposite gap. The voltage appearing on the impedance excites two TEM-wave packets: one propagates backwards, another one propagates forward through connector. The connector output is sum of two such packets spaced the same as two incident packets. The packets propagating backwards reflect from the electrode open end, come back to the summing point and generate output in similar way. The same processes occur in a pickup with single gap electrodes (stripline pickup). This phenomenological picture can be used as a guide in pickup design and simulation.
	Poster WEPC26 [0.647 MB]

WEPC31	New Design of the 40 GHz Bunch Arrival Time Monitor Using MTCA.4 Electronics at FLASH and for the European XFEL	laser, XFEL, DESY, diagnostics	749
	M.K. Czwalinna, C. Gerth, H. Schlarb DESY, Hamburg, Germany S. Bou Habib Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland S. Korolczuk, J. Szewiński NCBJ, Świerk/Otwock, Poland A. Kuhl Uni HH, Hamburg, Germany
	At free-electron lasers, today's pump-probe experiments and seeding schemes make high demands on the electron bunch timing stability with an arrival time jitter reduction down to the femtosecond level. At FLASH and the upcoming European XFEL, the bunch train structures with their high bunch repetition rates allow for an accurate intra-train stabilisation. To realise longitudinal beam-based feedbacks a reliable and precise arrival time detection over a broad range of bunch charges, which can even change from 1 nC down to 20 pC within a bunch train, is essential. Benefitting from the experience at FLASH, the current bunch arrival time monitors (BAMs), based on detection of RF signals from broad-band pick-ups by use of electro-optic modulators, are further developed to cope with the increased requirements. In this paper, we present the new BAM prototype, including an adapted electro-optical front-end and the latest development of the read-out electronics based on the MTCA.4 platform.

WEPC40	Pickup Signal Improvement for High Bandwidth BAMs for FLASH and European - XFEL	simulation, DESY, laser, resonance	778
	A. Angelovski, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	In order to measure the arrival time of the electron bunches in low (20 pC) and high (1 nC) charge operation mode, new high bandwidth pickups were developed as a part of the Bunch Arrival-time Monitors (BAMs) for FLASH at DESY . The pickup signal is transported via radiation resistant coaxial cables to the electro-optic modulator (EOM) . Due to the high losses of the 40 GHz RF front-end the signal in the RF path is attenuated well below the optimal operation voltage of the EOM. To improve the overall performance, the signal strength of the induced pickup signal needs to be increased and at the same time the losses in the RF front-end significantly reduced. In this paper, the analysis towards improving the induced pickup signal strength is presented. Simulations are performed with the CST STUDIO SUITE package and the results are compared with the state of the art high bandwidth pickups. A. Angelovski et al., Phys. Rev. ST Accel. Beams 15, 112803 (2012) ** A. Penirschke et al., Proc. of IBIC2012, Tsukuba, Japan (2012)

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

WEPF28	Longitudinal Beam Diagnostic from a Distributed Electrostatic Pick-Up in CERN’s ELENA Ring	longitudinal, CERN, antiproton, diagnostics	883
	M.E. Angoletta, F. Caspers, S. Federmann, J.C. Molendijk, P.J. Pascal Jean, F. Pedersen, J. Sanchez-Quesada, L. Søby, M.A. Timmins CERN, Geneva, Switzerland
	The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Required longitudinal diagnostics include the intensity measurement for bunched and debunched beam and the measurement of Dp/p for a debunched beam to assess the electron cooling performance. A novel method for the calculation of these parameters is proposed for ELENA, where signals from the twenty electrostatic pick-ups (PU) used for orbit measurements will be combined to improve the signal-to-noise ratio. This requires that the signals be digitally down-converted, rotated and digitally summed so that the many electrostatic PUs will function as a single, distributed PU from to the processing system viewpoint. This method includes some challenges and will not be used as the baseline longitudinal diagnostics for the initial ELENA operation. This paper gives an overview of the hardware and digital signal processing involved, as well as of the challenges that will have to be faced.

WEPF31	A FESA DAQ for Fast Current Transformer in SIS 18	synchrotron, longitudinal, CERN, SIS	894
	O. Chorniy, H. Bräuning, T. Hoffmann, H. Reeg, A. Reiter GSI, Darmstadt, Germany
	This contribution presents the development of the data acquisition (DAQ) system for the readout of fast beam current transformers (FCT) as installed in the GSI synchrotron SIS18 and as foreseen in several FAIR ring accelerators. Fast current transformers are reliable devices that offer a large analogue bandwidth and can therefore monitor bunch structures with high resolution. At appropriate sampling rates continuous measurements throughout repeated machine cycles lead to a large amount of raw data. The analysis of those raw data may range from simple bunch parameter calculations to complex longitudinal phase space reconstructions. Consequently, a new DAQ system must be carefully designed to allow for flexible acquisition modes or to allow for data reduction methods in special applications. The aims of the development are discussed and the status of the new DAQ is presented.
	Poster WEPF31 [2.307 MB]

WEPF32	Measurement and Control of the Beam Energy for the SPIRAL2 Accelerator	controls, SPIRAL2, linac, rfq	897
	W. Le Coz, C. Doutresssoulles, C. Jamet, G. Ledu, S. Loret, C. Potier de courcy GANIL, Caen, France
	The first part of the SPIRAL2 facility, which entered last year in the construction phase at GANIL in France, will be composed of an ion source, a deuteron/proton source, a RFQ and a superconducting linear accelerator delivering high intensities, up to 5 mA and 40 MeV for the deuteron beams. As part of the MEBT commissioning, the beam energy will be measured on the BTI (Bench of Intermediate Test) at the exit of the RFQ. At the exit of the LINAC, the system has to measure but also control the beam energy. The control consists in ensuring that the beam energy is under a limit by taking account of the measurement uncertainty. The energy is measured by a method of time of flight, the signal is captured by non-intercepting capacitive pick-ups. This paper presents also the results obtained in terms of uncertainties and dynamics of measures.

Paper

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Other Keywords

Page

MOAL4

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

laser, gun, feedback, electron

8

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

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

Slides MOAL4 [1.228 MB]

MOBL3

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

ELBE, electron, laser, diagnostics

23

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

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

Slides MOBL3 [3.578 MB]

MOPC09

Development of the Sirius RF BPM Electronics

BPM, controls, storage-ring, simulation

63

D.O. Tavares, R.A. Baron, F.H. Cardoso, S.R. Marques, J.L.B. Neto, L.M. Russo
LNLS, Campinas, Brazil
A.P. Byszuk, G. Kasprowicz, A.J. Wojenski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

A BPM system has been developed for the new low emmitance 3 GeV Brazilian synchrotron light source, Sirius. The Sirius BPM electronics is a modular system based on a PICMG(R) MicroTCA.4 platform using ADC mezzanine cards in ANSI/VITA 57.1 FMC form factor and standalone RF front-end boards. It has been designed under the CERN Open Hardware License (OHL) in a collaboration between Brazilian Synchrotron Light Laboratory (LNLS) and Warsaw University of Technology (WUT). This paper presents: i) overall architecture of the BPM system; ii) performance evaluation of the first prototype of the BPM electronics comprehending beam current, filling pattern and temperature dependencies as well as resolution vs. beam current; and iii) preliminary results with beam at LNLS's UVX storage ring.

Poster MOPC09 [1.451 MB]

MOPC14

Beam Position Monitors R&D for keV Ion Beams

simulation, BPM, antiproton, multipole

78

S. Naveed, A.A. Nosych, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S. Naveed, A.A. Nosych, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A.A. Nosych, L. Søby
CERN, Geneva, Switzerland

Funding: Work supported by the EU within the DITANET and oPAC projects under contracts 215080 and 289485, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams on the examples of the USR and ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values and describe an experimental setup realized at the Cockcroft Institute for BPM callibration. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably.

MOPC19

Status of the Beam Position Monitors for LIPAc

BPM, simulation, beam-position, linac

93

I. Podadera, F.M. De Aragon, A. Guirao, D. Jimenez, A. Lara, L.M. Martinez, J. Molla
CIEMAT, Madrid, Spain

Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC10-A-000441 and AIC-A-2011-0654.
The LIPAc 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. Several types of Beam Position Monitors BPM’s- are placed in each section of the accelerator to ensure a good beam transport and minimize beam losses. Prototypes of almost all the BPM’s have been already fabricated. Acceptance tests have been carried out on each device. The output of the vacuum leak tests and electrical tests will be analyzed in this contribution. In addition, the test bench to characterize the BPM’s has been upgraded and validated using some prototypes in order to obtain a better global measurement accuracy of the electrical center offset. The test bench can be used to crosscheck the simulations with the real response of each BPM. The result of the comparison will be discussed in detail.

MOPC25

About BPMS to be Used for PAL-XFEL

BPM, XFEL, electron, beam-position

112

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

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

MOPC26

Optimization of Bunch-to-Bunch Isolation in Instability Feedback Systems

coupling, feedback, kicker, FIR

116

D. Teytelman
Private Address, San Jose, USA

Bunch-by-bunch feedback formalism is a powerful tool for combating coupled-bunch instabilities in circular accelerators. Imperfections in the analog front and back ends lead to coupling between neighboring bunches. Such coupling limits system performance in both feedback and diagnostic capacities. In this paper, techniques for optimizing bunch-to-bunch isolation within the system will be presented. A new method for improving the performance of the existing systems will be described. The novel approach uses a "shaper" filter in the digital signal processor to compensate for the imperfect response of the power amplifier and kicker combination. An objective optimization method to derive the optimal back end configuration will be presented and illustrated with measurements from several accelerators.

Poster MOPC26 [0.851 MB]

MOPC42

Novel Pickup for Bunch Arrival Time Monitor

LEFT, transverse, simulation, laser

170

A. Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

For an optical-modulator-based BAM, main parameter of the pickup output signal is slope steepness. We suggest a novel pickup with flat thin electrodes in a transverse gap. Increasing the electrode width makes the steepness greater in the same extent as the signal increases. For a given width, reducing the electrode thickness allows to reach ultimate steepness. Wave processes in the pickup were investigated on a large scale model, using the technique described in *. The DESY 40GHz button pickup was used as a reference. It is shown that steepness of the flat electrode pickup can be achieved two times greater. It is also shown that a BAM electrode pickup has a remarkable feature: the steepness does not depend on electrode sizes, if the ratio w/G (a flat electrode pickup, the width and gap length) or d/D (a button pickup, the diameters) is kept constant. This makes pickup bandwidth that is of the order of c over 2G or 2D, a free parameter. For flat electrode pickup, the steepness can be kept as high with transition to a more practical bandwidth 20GHz. The investigation results are the base for a final pickup optimisation using electrodynamic simulation.
* A. Kalinin, “Pickup Electrode Electrodynamics Investigation”, WEPC26, this conference

Poster MOPC42 [0.549 MB]

TUBL3

A Multiband-Instability-Monitor for High-Frequency Intra-Bunch Beam Diagnostics

LHC, CERN, SPS, synchrotron

327

R.J. Steinhagen
CERN, Geneva, Switzerland
M.J. Boland, T.G. Lucas
The University of Melbourne, Melbourne, Australia

To provide the best possible luminosity, even higher beam intensities are needed in the Large Hadron Collider (LHC) and in its injector chain. This is fundamentally limited by self-amplifying beam instabilities, intrinsic to unavoidable imperfections in accelerators. Traditionally, intra-bunch or head-tail particle motion is measured using fast digitizers, which even using state-of-the-art technology are limited in their effective intra-bunch position resolution to few tens of um in the multi-GHz regime. Oscillations at this scale cause partial or total loss of the beam due to the tight transverse constraints imposed by the LHC collimation system. To improve on the present signal processing, a prototype system has been designed, constructed and tested at the CERN Super-Proton-Synchrotron (SPS) and later on LHC. The system splits the signal into multiple equally-spaced narrow frequency bands that are processed and analysed in parallel. Working with narrow-band signals in frequency-domain permits the use of much higher resolution analogue-to-digital-converters that can be used to resolve nm-scale particle motion already during the onset of instabilities.

Slides TUBL3 [3.165 MB]

TUPC14

Development of a Low-Beta Button BPM for PXIE Project

BPM, simulation, beam-position, longitudinal

392

A. Lunin, N. Eddy, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev
Fermilab, Batavia, USA

The button BPM is under development for a low beta section of the Project X Injector Experiment (PXIE) at Fermilab. The presented paper includes an analytical estimation of the BPM performance as well a direct wakefield simulation with CST Particle Studio (on a hexahedral mesh). In addition we present a novel approach of a low beta beam interaction with BPM electrodes realized with ANSYS HFSS TD-solver on unstructured tetrahedral mesh. Both methods show a good agreement of BPM output signals for various beam parameters. Finally we describe the signal processing scheme and the electronics we are going to use.

Poster TUPC14 [1.051 MB]

TUPC19

First Beam Tests of a Prototype Cavity Beam Position Monitor for the CLIC Main Beam

single-bunch, beam-position, BPM, dipole

411

F.J. Cullinan, S.T. Boogert, A. Lyapin, J.R. Towler
JAI, Egham, Surrey, United Kingdom
W. Farabolini, T. Lefèvre, L. Søby, M. Wendt
CERN, Geneva, Switzerland

Beam position monitors (BPMs) throughout the CLIC (Compact Linear Collider) main linac and beam delivery system must routinely operate at 50 nm resolution and be able to make multiple position measurements within a single 156 ns long bunch train. A prototype cavity beam position monitor, designed to demonstrate this performance, has been tested on the probe beamline of CTF3 (the CLIC Test Facility). Sensitivity measurements of the dipole mode position cavity and of the monopole mode reference cavity have been made. The characteristics of signals from short and long bunch trains and the dominant systematic effects have also been studied.

TUPC20

Technologies and R&D for a High Resolution Cavity BPM for the CLIC Main Beam

BPM, CLIC, CTF3, coupling

415

J.R. Towler, T. Lefèvre, L. Søby, M. Wendt
CERN, Geneva, Switzerland
S.T. Boogert, F.J. Cullinan, A. Lyapin
JAI, Egham, Surrey, United Kingdom

The Main Beam (MB) LINAC of the Compact Linear Collider (CLIC) requires a beam orbit measurement system with a high spatial (50 nm) and high temporal (50 ns) resolution to resolve the beam position within the 156 ns long bunch train, traveling on an energy-chirped, minimum dispersive trajectory. A 15 GHz prototype cavity BPM has been commissioned in the probe beam-line of the CTF3 CLIC Test Facility. The performance and technical details of this prototype installation are discussed in this paper, including the 15 GHz analog down-converter, the data acquisition and the control electronics and software. An R&D outlook is given for the next steps, which requires a system of 3 cavity BPMs to investigate the full resolution potential.

TUPC25

Design of the SwissFEL BPM System

BPM, XFEL, undulator, linac

427

B. Keil, R. Baldinger, R. Ditter, W. Koprek, R. Kramert, F. Marcellini, G. Marinkovic, M. Roggli, M. Rohrer, M. Stadler, D.M. Treyer
PSI, Villigen PSI, Switzerland

SwissFEL is a Free Electron Laser (FEL) facility being constructed at PSI, based on a 5.8GeV normally conducting main linac. A photocathode gun will generate two bunches with 28ns spacing at 100Hz repetition rate, with a nominal charge range of 10-200pC. A fast beam distribution kicker will allow to distribute one bunch to a soft X-ray undulator line and the other bunch to a 0.1nm hard X-ray undulator line. The SwissFEL electron beam position monitor (BPM) system will employ three different types of dual-resonator cavity BPMs, since the accelerator has three different beam pipe apertures. In the injector and main linac (38mm and 16mm aperture), 3.3GHz cavity BPMs will be used, where a low Q of ~40 was chosen to minimize crosstalk of the two bunches*. In the undulators that just have single bunches and 8mm BPM aperture, a higher Q will be chosen. This paper reports on the development status of the SwissFEL BPM system. Synergies as well as differences to the E-XFEL BPM system** will also be highlighted.
* F. Marcellini et al., "Design of Cavity BPM Pickups For SwissFEL", Proc. IBIC'12, Tsukuba, Japan, 2012.
** B. Keil et al., "The European XFEL BPM System", Proc. IPAC'10, Kyoto, Japan, 2010.

Poster TUPC25 [1.074 MB]

TUPC29

Grounded Coplanar Waveguide Transmission Lines as Pickups for Beam Position Monitoring in Particle Accelerators

XFEL, simulation, beam-position, coupling

438

A. Penirschke, A. Angelovski, R. Jakoby
TU Darmstadt, Darmstadt, Germany
C. Gerth, U. Mavrič, D. Nölle, C. Sydlo, S. Vilcins
DESY, Hamburg, Germany

Funding: The work was supported by the MSK group at DESY Hamburg. The authors would like to thank the CST AG for providing the CST Software Package.
Energy beam position monitors (EBPM) based on grounded co-planar waveguide (GCPW) transmission lines have been designed for installation in the dispersive sections of the bunch compressor chicanes at the European XFEL. In combination with beam position monitors at the entrance and exit of the bunch compressor chicanes, measurements of the beam energy with single bunch resolution are feasible. The EBPM consists of transversely mounted stripline pickups in a rectangular beam pipe section. The signal detection for the measurement of the phases of the pulses at each end of the pickups is based on the standard down-conversion and phase detection scheme used for the low-level RF-system. A measurement resolution within the lower micrometer range can be achieved for input signal reflections at the pickup of less than -25 dB at 3 GHz. In this paper, simulation results of a novel pickup geometry utilized with GCPW pickup structures and optimized transitions to perpendicular mounted coaxial connectors are presented. The simulation results exhibit small reflection coefficients with reflected signal components having less than 2% of the peak voltage signal.

TUPC35

Upgrade of the Read-out Electronics for the Energy Beam Position Monitors at FLASH and European XFEL

XFEL, beam-position, DESY, SNR

454

U. Mavrič, C. Gerth, H. Schlarb
DESY, Hamburg, Germany
A. Piotrowski
TUL-DMCS, Łódź, Poland

The dispersive sections of magnetic bunch compressor chicanes at free-electron lasers are excellent candidates for beam energy measurements. In the rectangular beamline sections of the bunch compressors at FLASH, energy beam position monitors (EBPM) with transversely mounted stripline pickups are installed. In this paper, we present the upgrade of the read-out electronics for signal detection of the EBPM installed at FLASH. The system is based on the MTCA.4 standard and reuses already available MTCA.4 compliant modules. This is also true for gateware and software development which fits into standard MTCA.4 framework development. The performance of the instrument was studied at FLASH during user operation and the results are presented.

TUPF27

An Ultra Low-Noise AC Beam Transformer and Digital Signal Processing System for CERN’s ELENA Ring

CERN, diagnostics, longitudinal, extraction

571

M.E. Angoletta, C. Carli, F. Caspers, S. Federmann, J.C. Molendijk, F. Pedersen, J. Sanchez-Quesada
CERN, Geneva, Switzerland

CERN’s Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator. Essential longitudinal diagnostics required for commissioning and operation include the intensity measurement for bunched and debunched beams and the measurement of Dp/p for debunched beams to assess the electron cooling performance. The beam phase information is also needed by the low-level RF system. The baseline system for providing the required beam parameters and signals is based upon two ultra-low-noise AC beam transformers and associated digital signal processing. The AC beam transformers cover different frequency regions and are an adaptation to the ELENA layout of those used in the AD. Two AC beam transformers will also be installed in the extraction lines to provide beam intensity and bunch shape measurements. The digital signal processing will be carried out with the leading-edge hardware family used for ELENA’s low-level RF system. The paper provides an overview of the beam transformer and head amplifier, as well as of the associated digital signal processing.

TUPF31

Intensity Control in GANIL’s Experimental Rooms

diagnostics, controls, simulation, instrumentation

587

C. Courtois, C. Doutresssoulles, B. Ducoudret, C. Jamet, W. Le Coz, G. Ledu, C. Potier de courcy
GANIL, Caen, France

The safety re-examination of existing GANIL facilities requires the implementation of a safety system which makes a control of beam intensities sent in the experimental rooms possible. The aim is to demonstrate that beam intensities are below the authorized limits. The required characteristics should enable the measurement, by a non-interceptive method, of beam intensities from 5 nA to 5μA with a maximum uncertainty of 5%, independently of the frequency and the beam energy. After a comparative study, two types of high frequency diagnostics were selected, the capacitive peak-up and the Fast current transformer. This paper presents the signal simulations from diagnostics with different beam energies, the uncertainty calculations and the results of the first tests with beam.

Poster TUPF31 [2.086 MB]

TUPF32

A Cryogenic Current Comparator for FAIR with Improved Resolution

cryogenics, DESY, shielding, longitudinal

590

R. Geithner, W. Vodel
HIJ, Jena, Germany
R. Geithner, R. Neubert, P. Seidel
FSU Jena, Jena, Germany
F. Kurian, H. Reeg, M. Schwickert
GSI, Darmstadt, Germany

A Cryogenic Current Comparator is a highly sensitive tool for the non-destructive online monitoring of continuous as well as bunched beams of very low intensities. The noise-limited current resolution of such a device depends on the ferromagnetic material embedded in the pickup coil of the CCC. Therefore, the main focus of research was on the low temperature properties of ferromagnetic core materials. In this contribution we present first results of the completed Cryogenic Current Comparator for FAIR working in a laboratory environment, regarding the improvements in resolution due to the use of suitable ferromagnetic core materials.

Poster TUPF32 [3.868 MB]

TUPF34

Resonant TE Wave Measurement of Electron Cloud Density Using Multiple Sidebands

resonance, simulation, electron, positron

597

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

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

Poster TUPF34 [2.423 MB]

TUPF36

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

electron, resonance, vacuum, BPM

605

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

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

WEPC05

The ELENA Beam Diagnostics Systems

antiproton, electron, proton, CERN

664

G. Tranquille
CERN, Geneva, Switzerland

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

Poster WEPC05 [1.767 MB]

WEPC12

Evaluation of Strip-line Pick-up System for the SPS Wideband Transverse Feedback System

SPS, feedback, transverse, coupling

690

G. Kotzian, W. Höfle, R.J. Steinhagen, D. Valuch, U. Wehrle
CERN, Geneva, Switzerland

The proposed SPS Wideband Transverse Feedback system requires a wide-band pick-up system to be able to detect intra-bunch motion within the SPS proton bunches, captured and accelerated in a 200 MHz bucket. We present the electro-magnetic design of transverse beam position pick-up options optimised for installation in the SPS and evaluate their performance reach with respect to direct time domain sampling of the intra-bunch motion. The analysis also discusses the achieved subsystem responses of the associated cabling with new low dispersion smooth wall cables, wide-band generation of intensity and position signals by means of 180 degree RF hybrids as well as passive techniques to electronically suppress the beam offset signal, needed to optimise the dynamic range and position resolution of the planned digital intra-bunch feedback system.

WEPC16

The Design of BPM Electronic System for CSNS RCS

BPM, extraction, injection, beam-position

706

W. Lu, H.Y. Sheng, X.C. Tian, J.W. Zhao, Y.B. Zhao
IHEP, Bejing, People's Republic of China

A Beam Position Monitor (BPM) system has been designed for the Rapid Cycling Synchrotron (RCS) at the China Spallation Neutron Source (CSNS) to acquire beam position information. This article introduces the design and implementation of the BPM electronic system. The challenge of designing the BPM electronics is to acquire and process the signal with large dynamic range (5.8mV~32V) and changing width (80ns to 500ns). The analog circuit described in this paper, which is constructed of a single-stage operational amplifier and an analog switch, can cover the input signal with large dynamic range. Because of the minimum bunch length (80ns) and the requirement of position resolution, a 14 bit 250MHz ADC is adopted to digitize the signal. Besides, for BPM system, the demand of an accurate real-time position monitoring is mandatory. The algorithm developed in an FPGA is able to make Bunch-by-Bunch position calculation and Closed Orbit position calculation in real time. Also, some preliminary test results will be presented and discussed, which show that the resolution of Bunch-by-Bunch position is 0.8mm when the input signal is 5.8mV and the resolution of Closed Orbit position is 50um.

Poster WEPC16 [0.937 MB]

WEPC17

Design and Simulation of Beam Position Monitor for the CADS Injector I Proton Linac

BPM, simulation, linac, impedance

710

Y.F. Sui, J.S. Cao, H.Z. Ma, Q. Ye, J. Yue
IHEP, People's Republic of China

Funding: Work supported by the National Natural Science Foundation of China (NO. 11205172)
Beam Position Monitors (BPM) based on both capacitive and stripline pick-ups are designed for the China Accelerator Driven Subcritical system (C-ADS) Injector I proton LINAC. The BPM will be installed to measure the transverse beam position in the LINAC, of which the beam parameters are listed as current 10mA, energy 10MeV and the repetition frequency 325MHz. This contribution presents the status of the BPM design development and focuses on the design of the pick-ups and CST Particle Studio simulation results, including impedance, sensitivity, time domain, frequency domain response, etc. The main goal of the simulation is optimization of the mechanical design.

WEPC21

Design and Beam Test Results of Button BPMs for the European XFEL

BPM, XFEL, controls, DESY

723

D.M. Treyer, R. Baldinger, R. Ditter, B. Keil, W. Koprek, G. Marinkovic, M. Roggli
PSI, Villigen PSI, Switzerland
D. Lipka, D. Nölle, S. Vilcins
DESY, Hamburg, Germany

Funding: Swiss State Secretariat for Education, Research and Innovation
The European X-ray Free Electron Laser (E-XFEL) will use a total ~300 button BPMs along the whole accelerator, as well as 160 cavity BPMs. The pickups for the button BPMs have been designed by DESY, whereas the electronics has been developed by PSI. This paper gives an overview of the button BPM system, with focus on the RF front end electronics, signal processing, and overall system performance. Measurement results achieved with prototypes installed at FLASH/DESY and at the SwissFEL Injector Test Facility (SITF) are presented. The position noise obtained with button pickups in a 40.5 mm aperture beam pipe is as low as ~11 um at 20 pC bunch charge.

Poster WEPC21 [1.595 MB]

WEPC26

Pickup Electrode Electrodynamics Investigation

LEFT, transverse, impedance, vacuum

742

A. Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Waves induced in a pickup by beam were investigated on a large scale model, using 10ps step in coaxial line as beam, and a differentiating capacitive probe. The probe signal was observed at 20GHz oscilloscope. In each of the front and rear transverse gaps between pickup electrode and wall (button pickup), a shorter-than-gap bunch excites a ‘plain-wave’ packet which length is of the order of gap length over c. Two packets are spaced by electrode length over c. The packets propagate along the electrode to a coaxial connector. At this low impedance common point each of the packets partially reflects back and partially passes into the opposite gap. The voltage appearing on the impedance excites two TEM-wave packets: one propagates backwards, another one propagates forward through connector. The connector output is sum of two such packets spaced the same as two incident packets. The packets propagating backwards reflect from the electrode open end, come back to the summing point and generate output in similar way. The same processes occur in a pickup with single gap electrodes (stripline pickup). This phenomenological picture can be used as a guide in pickup design and simulation.

Poster WEPC26 [0.647 MB]

WEPC31

New Design of the 40 GHz Bunch Arrival Time Monitor Using MTCA.4 Electronics at FLASH and for the European XFEL

laser, XFEL, DESY, diagnostics

749

M.K. Czwalinna, C. Gerth, H. Schlarb
DESY, Hamburg, Germany
S. Bou Habib
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
S. Korolczuk, J. Szewiński
NCBJ, Świerk/Otwock, Poland
A. Kuhl
Uni HH, Hamburg, Germany

At free-electron lasers, today's pump-probe experiments and seeding schemes make high demands on the electron bunch timing stability with an arrival time jitter reduction down to the femtosecond level. At FLASH and the upcoming European XFEL, the bunch train structures with their high bunch repetition rates allow for an accurate intra-train stabilisation. To realise longitudinal beam-based feedbacks a reliable and precise arrival time detection over a broad range of bunch charges, which can even change from 1 nC down to 20 pC within a bunch train, is essential. Benefitting from the experience at FLASH, the current bunch arrival time monitors (BAMs), based on detection of RF signals from broad-band pick-ups by use of electro-optic modulators, are further developed to cope with the increased requirements. In this paper, we present the new BAM prototype, including an adapted electro-optical front-end and the latest development of the read-out electronics based on the MTCA.4 platform.

WEPC40

Pickup Signal Improvement for High Bandwidth BAMs for FLASH and European - XFEL

simulation, DESY, laser, resonance

778

A. Angelovski, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

In order to measure the arrival time of the electron bunches in low (20 pC) and high (1 nC) charge operation mode, new high bandwidth pickups were developed as a part of the Bunch Arrival-time Monitors (BAMs) for FLASH at DESY *. The pickup signal is transported via radiation resistant coaxial cables to the electro-optic modulator (EOM) **. Due to the high losses of the 40 GHz RF front-end the signal in the RF path is attenuated well below the optimal operation voltage of the EOM. To improve the overall performance, the signal strength of the induced pickup signal needs to be increased and at the same time the losses in the RF front-end significantly reduced. In this paper, the analysis towards improving the induced pickup signal strength is presented. Simulations are performed with the CST STUDIO SUITE package and the results are compared with the state of the art high bandwidth pickups.
* A. Angelovski et al., Phys. Rev. ST Accel. Beams 15, 112803 (2012)
** A. Penirschke et al., Proc. of IBIC2012, Tsukuba, Japan (2012)

WEPC41

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

laser, electron, insertion, free-electron-laser

782

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

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

Poster WEPC41 [0.619 MB]

WEPF28

Longitudinal Beam Diagnostic from a Distributed Electrostatic Pick-Up in CERN’s ELENA Ring

longitudinal, CERN, antiproton, diagnostics

883

M.E. Angoletta, F. Caspers, S. Federmann, J.C. Molendijk, P.J. Pascal Jean, F. Pedersen, J. Sanchez-Quesada, L. Søby, M.A. Timmins
CERN, Geneva, Switzerland

The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Required longitudinal diagnostics include the intensity measurement for bunched and debunched beam and the measurement of Dp/p for a debunched beam to assess the electron cooling performance. A novel method for the calculation of these parameters is proposed for ELENA, where signals from the twenty electrostatic pick-ups (PU) used for orbit measurements will be combined to improve the signal-to-noise ratio. This requires that the signals be digitally down-converted, rotated and digitally summed so that the many electrostatic PUs will function as a single, distributed PU from to the processing system viewpoint. This method includes some challenges and will not be used as the baseline longitudinal diagnostics for the initial ELENA operation. This paper gives an overview of the hardware and digital signal processing involved, as well as of the challenges that will have to be faced.

WEPF31

A FESA DAQ for Fast Current Transformer in SIS 18

synchrotron, longitudinal, CERN, SIS

894

O. Chorniy, H. Bräuning, T. Hoffmann, H. Reeg, A. Reiter
GSI, Darmstadt, Germany

This contribution presents the development of the data acquisition (DAQ) system for the readout of fast beam current transformers (FCT) as installed in the GSI synchrotron SIS18 and as foreseen in several FAIR ring accelerators. Fast current transformers are reliable devices that offer a large analogue bandwidth and can therefore monitor bunch structures with high resolution. At appropriate sampling rates continuous measurements throughout repeated machine cycles lead to a large amount of raw data. The analysis of those raw data may range from simple bunch parameter calculations to complex longitudinal phase space reconstructions. Consequently, a new DAQ system must be carefully designed to allow for flexible acquisition modes or to allow for data reduction methods in special applications. The aims of the development are discussed and the status of the new DAQ is presented.

Poster WEPF31 [2.307 MB]

WEPF32

Measurement and Control of the Beam Energy for the SPIRAL2 Accelerator

controls, SPIRAL2, linac, rfq

897

W. Le Coz, C. Doutresssoulles, C. Jamet, G. Ledu, S. Loret, C. Potier de courcy
GANIL, Caen, France

The first part of the SPIRAL2 facility, which entered last year in the construction phase at GANIL in France, will be composed of an ion source, a deuteron/proton source, a RFQ and a superconducting linear accelerator delivering high intensities, up to 5 mA and 40 MeV for the deuteron beams. As part of the MEBT commissioning, the beam energy will be measured on the BTI (Bench of Intermediate Test) at the exit of the RFQ. At the exit of the LINAC, the system has to measure but also control the beam energy. The control consists in ensuring that the beam energy is under a limit by taking account of the measurement uncertainty. The energy is measured by a method of time of flight, the signal is captured by non-intercepting capacitive pick-ups. This paper presents also the results obtained in terms of uncertainties and dynamics of measures.