IBIC2012 - List of Keywords (pick-up)

Paper	Title	Other Keywords	Page
MOPA07	Development of a Phase Probe for the NIRS Small Cyclotron HM-18	cyclotron, ion, operation, acceleration	60
	S. Hojo, A. Goto, T. Honma, K. Katagiri, A. Sugiura NIRS, Chiba-shi, Japan Y. Takahashi AEC, Chiba, Japan
	The small cyclotron HM-18 of the National Institute of Radiological Sciences (NIRS) has been operated for use in RI production since 1994. The HM-18 allows us to accelerate protons and deuterons at fixed energies of 18 and 9 MeV, respectively. It has four trim coils for generation of the isochronous fields. Until recently, currents of the four trim coils had been adjusted only by monitoring the output beam intensity. In order to exactly produce the isochronous fields, a new phase probe has been installed in the HM-18. The phase probe has a simple structure in which four copper electrode plates of 60 mm x70 mm in area are glued to a copper base plate with a polyimide insulator between them. The thicknesses of the copper plates and the polyimide are 0.1 mm. This structure has an advantage that it can be easily installed in the cyclotron; only one part of a pair of upper and lower electrodes, which is usually adopted, is simply attached on the surface of the (lower) sector pole. The development of the phase probe and some results of a preliminary beam test using it are reported.

MOPA16	Design and Characterization of a Prototype Stripline Beam Position Monitor for the CLIC Drive Beam	simulation, damping, impedance, electronics	87
	A. Benot-Morell, L. Søby, M. Wendt CERN, Geneva, Switzerland A. Benot-Morell IFIC, Valencia, Spain J.M. Nappa, J. Tassan-Viol, S. Vilalte IN2P3-LAPP, Annecy-le-Vieux, France S.R. Smith SLAC, Menlo Park, California, USA
	Funding: FPA2010-21456-C02-01, SEIC-2010-00028 The prototype of a stripline Beam Position Monitor (BPM) with its associated readout electronics is under development at CERN, in collaboration with SLAC, LAPP and IFIC. The anticipated position resolution and accuracy are expected to be below 2μm and 20μm respectively for operation of the BPM in the CLIC drive beam (DB) linac. This paper describes the particular CLIC DB conditions with respect to the beam position monitoring, presents the measurement concept, and summarizes electromagnetic simulations and RF measurements performed on the prototype.

MOPA30	Application of EMMA BPMs to the ALICE Energy Recovery Linac	FEL, sextupole, EPICS, linac	117
	A. Kalinin, D. Angal-Kalinin, F. Jackson, J.K. Jones, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The ALICE Energy Recovery Linac arc button pickups have been recently equipped with EMMA BPM electronics. These bunch-by-bunch EPICS VME BPMs give information about charge and position, and its jitter, allowing estimates of the beam energy jitter in ALICE in different modes of operation. A Mathematica program is designed to monitor statistically individual bunches (spacing 61.54ns) as well the train as a whole (up to 1625 bunches), allowing the study of jitter and position stability of the beam through the arc. The ALICE arc has been designed to be isochronous, with the bunch compression achieved through a separate dedicated bunch compressor chicane. The arc incorporates two sextupoles for correcting non-linear longitudinal matrix terms and experimental evidence suggests that the off-centred beam in the sextupoles breaks the linear isochronicity. We present some beam measurement results collected in 2012 using these BPMs. A. Kalinin et al, MOPPR061, IPAC12

MOPA31	Design and Fabrication of the Stripline BPM at ESS-Bilbao	coupling, controls, impedance, electronics	122
	S. Varnasseri, I. Arredondo, D. Belver, F.J. Bermejo, J. Feuchtwanger, N. Garmendia, P.J. González, L. Muguira ESS Bilbao, LEIOA, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	A Stripline type BPM is designed and fabricated at ESSB. In order to compare, in the future, the functionality and response of the previous BPM capacitive pick-ups design with stripline, a design for stripline BPM is proposed. The design is based on travelling wave electrodes principles to detect the transverse position of the beam in the vacuum chamber. In the design of stripline setup, it has been considered to keep the comparison conditions with pick-ups as similar as possible. The length of strip electrodes is 200 mm and the coverage angle is 0.952 rad. The structure is rotationally pi/2 symmetric and the alignment of electrodes are pi/4, 3pi/, 5pi/4 and 7pi/4. The design is optimized for a frequency of 352 MHz, however it can function on a wide range of frequencies out coming from the measurement results. Striplines in general have well defined behavior even for low beta and low intensity beams as well as functionality at low and high frequencies. A report on the design and characteristics measurement of Stripline will be presented. The characteristics like frequency range, electrodes insulation, electrode response, sensitivities to beam power and position will be presented.

MOPA43	RF Front end for High Bandwidth Bunch Arrival Time Monitors in Free-Electron Lasers at DESY	simulation, operation, electron, laser	157
	A. Penirschke, A. Angelovski, M. Hansli, R. Jakoby TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany A. Kuhl Uni HH, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" The Free-Electron Laser in Hamburg FLASH is equipped with Bunch Arrival-time Monitors (BAMs) that use an electro-optical detection scheme to modulate the intensity of the femtosecond laser pulse train with the pickup signals (). The achieved resolution of the existing BAMs are less than 10 fs for bunch charges higher than 500 pC. For lower bunch charges the time resolution drops significantly. Increased demands for low bunch charge operation modes of 20 pC and less at FLASH II and the European X-ray Free-Electron Laser XFEL require an upgrade of the existing beam diagnostic equipment. High bandwidth BAMs with newly developed cone-shaped pickups () promise sub-10 fs time resolution for both, the high and low bunch charge operation mode. This paper addresses the RF signal path of the high bandwidth BAMs for FLASH II and XFEL. It comprises radiation resistant coaxial cables, combiners and limiters up to a frequency of 40 GHz from the pickup electrodes to the Electro-optical Mach-Zehnder type modulator (EOM). Detailed investigations of the signal path using measurements and simulations with AWR Microwave Office allows for a good prediction of the signal quality and shape at the EOM. () F. Löhl et al., Phys. Rev. Lett. 104,144801 (2010) (**) A. Angelovski et al. in Proceedings of the International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 2011, p.1177

MOPA46	Realization and Measurements of Cone-shaped Pickups for Bunch Arrival-time Monitors for FLASH and XFEL	simulation, electron, laser, free-electron-laser	165
	A. Angelovski, M. Hansli, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany A. Kuhl Uni HH, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors" At the Free Electron Laser FLASH at DESY, the installed Bunch Arrival-time Monitors (BAMs) use an electro-optical detection scheme for arrival-time measurements. The achieved time resolution is in the sub-10 fs range for bunch charges higher than 500 pC. The extension of FLASH II and the European X-ray Free Electron Laser Project (XFEL) foresees a low charge operation mode with bunch charge of 20 pC or less. The time resolution of the BAMs significantly drops as the bunch charge reduces (). By expanding the bandwidth of the pickups one can increase the time resolution at low charges. In this paper, we present the characterization results of the manufactured cone-shaped pickups introduced in () with a bandwidth up to 40 GHz. The pickups mounted in a vacuum body exhibit four-fold rotational symmetry with respect to the beam pipe. Due to different beam pipe apertures for FLASH and XFEL, two bodies are manufactured. The rf properties of the mounted pickups in case of open and sealed body as well as the pickups separately are measured and compared to the simulation results obtained by CST STUDIO SUITE®. ()M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany, 2011, p.365 (**)A. Angelovski et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p.1177

MOPA47	Planar Transmission Line BPM for Horizontal Aperture Chicane for XFEL	simulation, electron, electronics, kicker	168
	A. Angelovski, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany C. Gerth, U. Mavrič, C. Sydlo DESY, Hamburg, Germany
	In order to obtain ultra-short bunches in the Free Electron Laser FLASH at DESY, the electron beam is compressed in magnetic chicanes. Precise knowledge of the beam position in the chicane is of great significance for the longitudinal dynamics control. In the current implementation cylindrical pickup-striplines mounted perpendicularly to the beam are used as a Beam Position Monitor (BPM)(). One can determine the horizontal beam position by measuring the phase difference of the beam induced signal at opposite ends of a pickup. Due to the different electrical and mechanical requirements for the European XFEL a new BPM has to be developed. In this paper, we present the design and analysis of a planar transmission line structure which is planned to be used as a BPM in the European XFEL. The planar design of the pickups can provide for proper impedance match to the subsequent electronics as well as sufficient mechanical stability along the aperture when using alumina substrates. A scaled non-hermetic prototype of the BPM is built and characterized by scattering parameters. The measurement results are compared to simulations obtained by CST STUDIO SUITE®. () K. Hacker at el, Proceedings of DIPAC 2007, Venice, Italy 2007, p.108

MOPB55	Electron Cloud Measurements using Shielded Pickups at CesrTA	electron, simulation, detector, synchrotron	198
	J.P. Sikora, J.A. Crittenden, J.S. Ginsberg, D. L. Rubin CLASSE, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. The Cornell storage ring was originally a positron/electron collider with beam energies ranging from 2 to 5 GeV. In 2008 it was reconfigured as the Cornell Electron Storage Ring Test Accelerator (CesrTA). An important part of the research at CesrTA is the study of the growth, decay and mitigation of electron clouds. Electron Cloud (EC) densities can be measured with a Shielded Pickup (SPU), where cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The signals produced by SPU have proved to be very useful in measuring the mitigating effect of different vacuum chamber surfaces - including differences in quantum efficiency as well as secondary and elastic yield. This has been accomplished through the careful comparison of observed signals with the output of the EC simulation code ECLOUD. We present example comparisons of data and simulation that show the effect of different surfaces as well as beam conditioning effects. In addition, some data has been acquired using a solenoid to produce a longitudinal magnetic field at the SPU. We will present our current understanding of the effect of a longitudinal magnetic field on SPU signals.

MOPB57	Overview of Beam Instrumentation and Tuning at RIKEN RI Beam Factory	ion, cyclotron, electron, acceleration	204
	N. Fukunishi, M. Fujimaki, O. Kamigaito, M. Kase, M. Komiyama, J. Ohnishi, H. Okuno, N. Sakamoto, H. Watanabe, T. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan R. Koyama SHI Accelerator Service Ltd., Tokyo, Japan
	RIKEN RI Beam Factory (RIBF) was constructed as the first of the next-generation radioactive-beam facilities aiming at investigating vast unknown fields of unstable nuclei. In order to obtain the world-most intense heavy-ion beams, we have employed, taking into account cost effectiveness, a multistage acceleration scheme including 4 ring cyclotrons. We have already obtained 1 pμA, 0.42 pμA, and 24 pnA beams for 18O, 48Ca and 124Xe ions, respectively. The present performance has been obtained by using very conventional beam instruments such as Faraday cups, wire scanners and so on. Beam instruments used in RIBF are briefly summarized putting emphasis on beam tuning methods using them. In addition, limitations of these conventional devices and possible upgrade of beam instruments are discussed for further intensity upgrades and more stable operations of RIBF.

MOPB85	Latest Results from the 4.8GHz LHC Schottky Systems	proton, ion, injection, experiment	279
	M. Favier, O.R. Jones CERN, Geneva, Switzerland
	This paper will present the latest results from the LHC 4.8GHz travelling wave Schottky system, summarising measurements performed during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies.

TUPA05	The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System	storage-ring, experiment, data-analysis, electron	334
	Y.L. Yang, C. Cheng, P. Lu, T.J. Ma, B.G. Sun, J.G. Wang, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by National Natural Science Project(11105141) and Chinese Universities Scientific Fund For bunch current measurement, the calibration factor is a key parameter. Usually, button electrode or stripline electrode can be selected as signal pickup, and peak value or integral of bunch signal from pickup can be used to calculate the related bunch current value. To obtain the absolute value of bunch current, the calibration factor should be determined with the help of DCCT. At HLS, the Stretch effect of bunch length was observed when bunch current decay over time and this will affect the performance of bunch current detection for different pickup type and calculate method. Theoretical analysis and experimental validation results are performed to find out an ideal solution for bunch current measurement at HLS. The results show that, bunch current measurement system can obtain the best performance by stripline and its integral signal.

TUPA15	Beam Postion Monitor for Energy Recovery Linac	linac, vacuum, electronics, monitoring	361
	I. Pinayev BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by US Department of Energy. The energy recovery linacs have co-propagating beams in the same vacuum vessel. These beams can have different trajectories, which should be distinguished by beam position monitors (BPM). In this paper we present a concept of BPM utilizing the phase information for calculation individual position of each of the two beams (accelerating and decelerating). The practical realizations are presented and achievable accuracy is estimated.

TUPA24	Design of Cavity BPM Pickups for SwissFEL	cavity, undulator, linac, coupling	390
	F. Marcellini, B. Keil, M. Rohrer, M. Stadler, J. Stettler, D.M. Treyer PSI, Villigen PSI, Switzerland D. Lipka, D. Nölle, M. Pelzer, S. Vilcins DESY, Hamburg, Germany
	SwissFEL is a 0.1nm hard X-ray Free Electron Laser being built at PSI. A photocathode gun, S-band injector and C-band linac provide 2 bunches at 28ns spacing, 10-200pC charge, and 5.8GeV maximum energy. A fast distribution kicker will provide one bunch each to one hard X-ray and one soft X-ray undulator line. For linac and undulators, first prototypes of dual-resonator cavity BPM pickups have been designed and fabricated. The pickups were optimized for low charge and short bunch spacing in the linac. Design considerations, simulation and first test results will be reported.

TUPA25	Signal Transmission Characteristics in Stripline-Type Beam Position Monitor	coupling, impedance, electronics, positron	394
	T. Suwada KEK, Ibaraki, Japan
	New stripline-type beam position monitor (BPM) system is under development at the KEKB injector linac in order to measure transverse beam positions with a high precision less than 10 micron meters towards the Super KEKB-factory (SKEKB) at KEK. During the KEKB operation, conventional stripline-type BPMs with a position resolution of 0.1 mm have been working well. However, the high-precision BPM system is strongly required for the SKEKB operation to stably accelerate single-bunch electron and positron beams with high bunch charges of ~5 nC/bunch, and also to keep the beam stability with higher brightness. The new stripline-type BPMs with large aperture compared with previously designed BPMs, which will be installed just after the positron production and capture section, have been designed. In this report, the basic design for fabricating the prototype stripline-type BPM, and, especially, theoretical analysis and experimental investigations on the signal propagation characteristics and performance along the stripling electrodes are described in detail on the base of a coupled-mode analysis of uniform coupled transmission lines.

TUPA27	Beam Test Results of Undulator Cavity BPM Electronics for the European XFEL	cavity, electronics, undulator, feedback	404
	M. Stadler, R. Baldinger, R. Ditter, B. Keil, R. Kramert, G. Marinkovic, M. Roggli PSI, Villigen PSI, Switzerland D. Lipka, D. Nölle, M. Pelzer, S. Vilcins DESY, Hamburg, Germany
	Funding: Work supported by Swiss State Secretariat for Education and Research SER The European X-ray Free Electron Laser (E-XFEL) will use dual-resonator cavity BPMs (CBPMs) in the SASE undulators to measure and stabilize the beam trajectory. The BPM electronics is developed by PSI, while the pickup mechanics is developed by DESY. First beam tests with three adjacent pickups have been performed. The system architecture and algorithms, achieved performance and noise correlation measurements of the present electronics prototypes will be presented.

TUPA32	Signal Equalizer for SPS Ecloud/TMCI Instability Feedback Control System	controls, feedback, network, resonance	424
	K.M. Pollock, J.E. Dusatko, J.D. Fox, C.H. Rivetta, D. Van Winkle SLAC, Menlo Park, California, USA R. Secondo CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract #DE-AC02-76F00515 and the US LHC Accelerator Research Program. The 4GS/sec electron cloud and transverse mode coupled instability (TMCI) control system in development for the CERN Super Proton Synchrotron (SPS) requires 1.5GHz of processing bandwidth for the beam pickups and signal digitizer. An exponentially tapered stripline pickup has sufficient bandwidth, but has a phase response that distorts the beam signal in the time domain. We report on results from the design and implementation of an equalizer for the front end signal processing with correction for the pickup and cable responses. Using a model of the transfer functions for the pickups and the cabling, we determine a desired frequency response for the equalizer. Design for the circuitry, component value fitting is discussed as well as board construction and reduction of parasitic impedances. Finally, we show results from the measurement of an assembled equalizer, compare them with simulations and show beam signals from use at the SPS.

WECC04	Analysis of the Electro-optical Front End for the New 40 GHz Bunch Arrival Time Monitor System	laser, electron, timing, FEL	571
	A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach Uni HH, Hamburg, Germany A. Angelovski, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo DESY, Hamburg, Germany S. Schnepp IFH, Zurich, Switzerland T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	The Free electron LASer in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAMs) which achieve a time resolution of less than 10 fs for bunch charges higher than 500 pC (1). In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With the current 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 (2) 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 pickup system also requires a new electro-optical frontend with a 40 GHz EOM. The theoretical limits of the time resolution depending on the RF signal at different bunch charges and on the jitter of the reference laser pulses where analyzed for the new EOM. (1) M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany,2011, p. 365 (2) A. Angelovski, A. Kuhl et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p. 1177 and p. 1186
	Slides WECC04 [12.560 MB]

THTA01	Beam Position Monitors for Circular Accelerators	impedance, coupling, resonance, closed-orbit	590
	S. Hiramatsu KEK, Ibaraki, Japan
	The electrostatic induction type beam position monitors (BPMs) for circular accelerators such as proton synchrotrons and electron accumulation rings will be discussed. Discussions on the beam induced charge on the BPM pick-up electrodes, signal detection systems, and techniques of beam based alignment and beam based calibration will be given. For high beam current machines, the evaluation of the beam coupling impedance of BPM is an important issue to avoid the beam current limit by beam instabilities caused by BPM impedances. Another serious problem is the movement of BPMs by the thermal distortion of the beam pipe by high power synchrotron radiation. These problems will be also mentioned briefly.
	Slides THTA01 [6.252 MB]

Paper

Title

Other Keywords

Page

MOPA07

Development of a Phase Probe for the NIRS Small Cyclotron HM-18

cyclotron, ion, operation, acceleration

60

S. Hojo, A. Goto, T. Honma, K. Katagiri, A. Sugiura
NIRS, Chiba-shi, Japan
Y. Takahashi
AEC, Chiba, Japan

The small cyclotron HM-18 of the National Institute of Radiological Sciences (NIRS) has been operated for use in RI production since 1994. The HM-18 allows us to accelerate protons and deuterons at fixed energies of 18 and 9 MeV, respectively. It has four trim coils for generation of the isochronous fields. Until recently, currents of the four trim coils had been adjusted only by monitoring the output beam intensity. In order to exactly produce the isochronous fields, a new phase probe has been installed in the HM-18. The phase probe has a simple structure in which four copper electrode plates of 60 mm x70 mm in area are glued to a copper base plate with a polyimide insulator between them. The thicknesses of the copper plates and the polyimide are 0.1 mm. This structure has an advantage that it can be easily installed in the cyclotron; only one part of a pair of upper and lower electrodes, which is usually adopted, is simply attached on the surface of the (lower) sector pole. The development of the phase probe and some results of a preliminary beam test using it are reported.

MOPA16

Design and Characterization of a Prototype Stripline Beam Position Monitor for the CLIC Drive Beam

simulation, damping, impedance, electronics

87

A. Benot-Morell, L. Søby, M. Wendt
CERN, Geneva, Switzerland
A. Benot-Morell
IFIC, Valencia, Spain
J.M. Nappa, J. Tassan-Viol, S. Vilalte
IN2P3-LAPP, Annecy-le-Vieux, France
S.R. Smith
SLAC, Menlo Park, California, USA

Funding: FPA2010-21456-C02-01, SEIC-2010-00028
The prototype of a stripline Beam Position Monitor (BPM) with its associated readout electronics is under development at CERN, in collaboration with SLAC, LAPP and IFIC. The anticipated position resolution and accuracy are expected to be below 2μm and 20μm respectively for operation of the BPM in the CLIC drive beam (DB) linac. This paper describes the particular CLIC DB conditions with respect to the beam position monitoring, presents the measurement concept, and summarizes electromagnetic simulations and RF measurements performed on the prototype.

MOPA30

Application of EMMA BPMs to the ALICE Energy Recovery Linac

FEL, sextupole, EPICS, linac

117

A. Kalinin, D. Angal-Kalinin, F. Jackson, J.K. Jones, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The ALICE Energy Recovery Linac arc button pickups have been recently equipped with EMMA BPM electronics*. These bunch-by-bunch EPICS VME BPMs give information about charge and position, and its jitter, allowing estimates of the beam energy jitter in ALICE in different modes of operation. A Mathematica program is designed to monitor statistically individual bunches (spacing 61.54ns) as well the train as a whole (up to 1625 bunches), allowing the study of jitter and position stability of the beam through the arc. The ALICE arc has been designed to be isochronous, with the bunch compression achieved through a separate dedicated bunch compressor chicane. The arc incorporates two sextupoles for correcting non-linear longitudinal matrix terms and experimental evidence suggests that the off-centred beam in the sextupoles breaks the linear isochronicity. We present some beam measurement results collected in 2012 using these BPMs.
*A. Kalinin et al, MOPPR061, IPAC12

MOPA31

Design and Fabrication of the Stripline BPM at ESS-Bilbao

coupling, controls, impedance, electronics

122

S. Varnasseri, I. Arredondo, D. Belver, F.J. Bermejo, J. Feuchtwanger, N. Garmendia, P.J. González, L. Muguira
ESS Bilbao, LEIOA, Spain
V. Etxebarria, J. Jugo, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

A Stripline type BPM is designed and fabricated at ESSB. In order to compare, in the future, the functionality and response of the previous BPM capacitive pick-ups design with stripline, a design for stripline BPM is proposed. The design is based on travelling wave electrodes principles to detect the transverse position of the beam in the vacuum chamber. In the design of stripline setup, it has been considered to keep the comparison conditions with pick-ups as similar as possible. The length of strip electrodes is 200 mm and the coverage angle is 0.952 rad. The structure is rotationally pi/2 symmetric and the alignment of electrodes are pi/4, 3pi/, 5pi/4 and 7pi/4. The design is optimized for a frequency of 352 MHz, however it can function on a wide range of frequencies out coming from the measurement results. Striplines in general have well defined behavior even for low beta and low intensity beams as well as functionality at low and high frequencies. A report on the design and characteristics measurement of Stripline will be presented. The characteristics like frequency range, electrodes insulation, electrode response, sensitivities to beam power and position will be presented.

MOPA43

RF Front end for High Bandwidth Bunch Arrival Time Monitors in Free-Electron Lasers at DESY

simulation, operation, electron, laser

157

A. Penirschke, A. Angelovski, M. Hansli, R. Jakoby
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
A. Kuhl
Uni HH, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free-Electron Laser in Hamburg FLASH is equipped with Bunch Arrival-time Monitors (BAMs) that use an electro-optical detection scheme to modulate the intensity of the femtosecond laser pulse train with the pickup signals (*). The achieved resolution of the existing BAMs are less than 10 fs for bunch charges higher than 500 pC. For lower bunch charges the time resolution drops significantly. Increased demands for low bunch charge operation modes of 20 pC and less at FLASH II and the European X-ray Free-Electron Laser XFEL require an upgrade of the existing beam diagnostic equipment. High bandwidth BAMs with newly developed cone-shaped pickups (**) promise sub-10 fs time resolution for both, the high and low bunch charge operation mode. This paper addresses the RF signal path of the high bandwidth BAMs for FLASH II and XFEL. It comprises radiation resistant coaxial cables, combiners and limiters up to a frequency of 40 GHz from the pickup electrodes to the Electro-optical Mach-Zehnder type modulator (EOM). Detailed investigations of the signal path using measurements and simulations with AWR Microwave Office allows for a good prediction of the signal quality and shape at the EOM.
(*) F. Löhl et al., Phys. Rev. Lett. 104,144801 (2010)
(**) A. Angelovski et al. in Proceedings of the International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 2011, p.1177

MOPA46

Realization and Measurements of Cone-shaped Pickups for Bunch Arrival-time Monitors for FLASH and XFEL

simulation, electron, laser, free-electron-laser

165

A. Angelovski, M. Hansli, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
A. Kuhl
Uni HH, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
At the Free Electron Laser FLASH at DESY, the installed Bunch Arrival-time Monitors (BAMs) use an electro-optical detection scheme for arrival-time measurements. The achieved time resolution is in the sub-10 fs range for bunch charges higher than 500 pC. The extension of FLASH II and the European X-ray Free Electron Laser Project (XFEL) foresees a low charge operation mode with bunch charge of 20 pC or less. The time resolution of the BAMs significantly drops as the bunch charge reduces (*). By expanding the bandwidth of the pickups one can increase the time resolution at low charges. In this paper, we present the characterization results of the manufactured cone-shaped pickups introduced in (**) with a bandwidth up to 40 GHz. The pickups mounted in a vacuum body exhibit four-fold rotational symmetry with respect to the beam pipe. Due to different beam pipe apertures for FLASH and XFEL, two bodies are manufactured. The rf properties of the mounted pickups in case of open and sealed body as well as the pickups separately are measured and compared to the simulation results obtained by CST STUDIO SUITE®.
(*)M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany, 2011, p.365
(**)A. Angelovski et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p.1177

MOPA47

Planar Transmission Line BPM for Horizontal Aperture Chicane for XFEL

simulation, electron, electronics, kicker

168

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

In order to obtain ultra-short bunches in the Free Electron Laser FLASH at DESY, the electron beam is compressed in magnetic chicanes. Precise knowledge of the beam position in the chicane is of great significance for the longitudinal dynamics control. In the current implementation cylindrical pickup-striplines mounted perpendicularly to the beam are used as a Beam Position Monitor (BPM)(*). One can determine the horizontal beam position by measuring the phase difference of the beam induced signal at opposite ends of a pickup. Due to the different electrical and mechanical requirements for the European XFEL a new BPM has to be developed. In this paper, we present the design and analysis of a planar transmission line structure which is planned to be used as a BPM in the European XFEL. The planar design of the pickups can provide for proper impedance match to the subsequent electronics as well as sufficient mechanical stability along the aperture when using alumina substrates. A scaled non-hermetic prototype of the BPM is built and characterized by scattering parameters. The measurement results are compared to simulations obtained by CST STUDIO SUITE®.
(*) K. Hacker at el, Proceedings of DIPAC 2007, Venice, Italy 2007, p.108

MOPB55

Electron Cloud Measurements using Shielded Pickups at CesrTA

electron, simulation, detector, synchrotron

198

J.P. Sikora, J.A. Crittenden, J.S. Ginsberg, D. L. Rubin
CLASSE, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The Cornell storage ring was originally a positron/electron collider with beam energies ranging from 2 to 5 GeV. In 2008 it was reconfigured as the Cornell Electron Storage Ring Test Accelerator (CesrTA). An important part of the research at CesrTA is the study of the growth, decay and mitigation of electron clouds. Electron Cloud (EC) densities can be measured with a Shielded Pickup (SPU), where cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The signals produced by SPU have proved to be very useful in measuring the mitigating effect of different vacuum chamber surfaces - including differences in quantum efficiency as well as secondary and elastic yield. This has been accomplished through the careful comparison of observed signals with the output of the EC simulation code ECLOUD. We present example comparisons of data and simulation that show the effect of different surfaces as well as beam conditioning effects. In addition, some data has been acquired using a solenoid to produce a longitudinal magnetic field at the SPU. We will present our current understanding of the effect of a longitudinal magnetic field on SPU signals.

MOPB57

Overview of Beam Instrumentation and Tuning at RIKEN RI Beam Factory

ion, cyclotron, electron, acceleration

204

N. Fukunishi, M. Fujimaki, O. Kamigaito, M. Kase, M. Komiyama, J. Ohnishi, H. Okuno, N. Sakamoto, H. Watanabe, T. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
R. Koyama
SHI Accelerator Service Ltd., Tokyo, Japan

RIKEN RI Beam Factory (RIBF) was constructed as the first of the next-generation radioactive-beam facilities aiming at investigating vast unknown fields of unstable nuclei. In order to obtain the world-most intense heavy-ion beams, we have employed, taking into account cost effectiveness, a multistage acceleration scheme including 4 ring cyclotrons. We have already obtained 1 pμA, 0.42 pμA, and 24 pnA beams for 18O, 48Ca and 124Xe ions, respectively. The present performance has been obtained by using very conventional beam instruments such as Faraday cups, wire scanners and so on. Beam instruments used in RIBF are briefly summarized putting emphasis on beam tuning methods using them. In addition, limitations of these conventional devices and possible upgrade of beam instruments are discussed for further intensity upgrades and more stable operations of RIBF.

MOPB85

Latest Results from the 4.8GHz LHC Schottky Systems

proton, ion, injection, experiment

279

M. Favier, O.R. Jones
CERN, Geneva, Switzerland

This paper will present the latest results from the LHC 4.8GHz travelling wave Schottky system, summarising measurements performed during the 2011 and 2012 LHC runs. It will also describe attempts to improve the system architecture in order to make it more immune to the strong coherent lines observed with proton bunches even at these very high frequencies.

TUPA05

The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System

storage-ring, experiment, data-analysis, electron

334

Y.L. Yang, C. Cheng, P. Lu, T.J. Ma, B.G. Sun, J.G. Wang, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by National Natural Science Project(11105141) and Chinese Universities Scientific Fund
For bunch current measurement, the calibration factor is a key parameter. Usually, button electrode or stripline electrode can be selected as signal pickup, and peak value or integral of bunch signal from pickup can be used to calculate the related bunch current value. To obtain the absolute value of bunch current, the calibration factor should be determined with the help of DCCT. At HLS, the Stretch effect of bunch length was observed when bunch current decay over time and this will affect the performance of bunch current detection for different pickup type and calculate method. Theoretical analysis and experimental validation results are performed to find out an ideal solution for bunch current measurement at HLS. The results show that, bunch current measurement system can obtain the best performance by stripline and its integral signal.

TUPA15

Beam Postion Monitor for Energy Recovery Linac

linac, vacuum, electronics, monitoring

361

I. Pinayev
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by US Department of Energy.
The energy recovery linacs have co-propagating beams in the same vacuum vessel. These beams can have different trajectories, which should be distinguished by beam position monitors (BPM). In this paper we present a concept of BPM utilizing the phase information for calculation individual position of each of the two beams (accelerating and decelerating). The practical realizations are presented and achievable accuracy is estimated.

TUPA24

Design of Cavity BPM Pickups for SwissFEL

cavity, undulator, linac, coupling

390

F. Marcellini, B. Keil, M. Rohrer, M. Stadler, J. Stettler, D.M. Treyer
PSI, Villigen PSI, Switzerland
D. Lipka, D. Nölle, M. Pelzer, S. Vilcins
DESY, Hamburg, Germany

SwissFEL is a 0.1nm hard X-ray Free Electron Laser being built at PSI. A photocathode gun, S-band injector and C-band linac provide 2 bunches at 28ns spacing, 10-200pC charge, and 5.8GeV maximum energy. A fast distribution kicker will provide one bunch each to one hard X-ray and one soft X-ray undulator line. For linac and undulators, first prototypes of dual-resonator cavity BPM pickups have been designed and fabricated. The pickups were optimized for low charge and short bunch spacing in the linac. Design considerations, simulation and first test results will be reported.

TUPA25

Signal Transmission Characteristics in Stripline-Type Beam Position Monitor

coupling, impedance, electronics, positron

394

T. Suwada
KEK, Ibaraki, Japan

New stripline-type beam position monitor (BPM) system is under development at the KEKB injector linac in order to measure transverse beam positions with a high precision less than 10 micron meters towards the Super KEKB-factory (SKEKB) at KEK. During the KEKB operation, conventional stripline-type BPMs with a position resolution of 0.1 mm have been working well. However, the high-precision BPM system is strongly required for the SKEKB operation to stably accelerate single-bunch electron and positron beams with high bunch charges of ~5 nC/bunch, and also to keep the beam stability with higher brightness. The new stripline-type BPMs with large aperture compared with previously designed BPMs, which will be installed just after the positron production and capture section, have been designed. In this report, the basic design for fabricating the prototype stripline-type BPM, and, especially, theoretical analysis and experimental investigations on the signal propagation characteristics and performance along the stripling electrodes are described in detail on the base of a coupled-mode analysis of uniform coupled transmission lines.

TUPA27

Beam Test Results of Undulator Cavity BPM Electronics for the European XFEL

cavity, electronics, undulator, feedback

404

M. Stadler, R. Baldinger, R. Ditter, B. Keil, R. Kramert, G. Marinkovic, M. Roggli
PSI, Villigen PSI, Switzerland
D. Lipka, D. Nölle, M. Pelzer, S. Vilcins
DESY, Hamburg, Germany

Funding: Work supported by Swiss State Secretariat for Education and Research SER
The European X-ray Free Electron Laser (E-XFEL) will use dual-resonator cavity BPMs (CBPMs) in the SASE undulators to measure and stabilize the beam trajectory. The BPM electronics is developed by PSI, while the pickup mechanics is developed by DESY. First beam tests with three adjacent pickups have been performed. The system architecture and algorithms, achieved performance and noise correlation measurements of the present electronics prototypes will be presented.

TUPA32

Signal Equalizer for SPS Ecloud/TMCI Instability Feedback Control System

controls, feedback, network, resonance

424

K.M. Pollock, J.E. Dusatko, J.D. Fox, C.H. Rivetta, D. Van Winkle
SLAC, Menlo Park, California, USA
R. Secondo
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract #DE-AC02-76F00515 and the US LHC Accelerator Research Program.
The 4GS/sec electron cloud and transverse mode coupled instability (TMCI) control system in development for the CERN Super Proton Synchrotron (SPS) requires 1.5GHz of processing bandwidth for the beam pickups and signal digitizer. An exponentially tapered stripline pickup has sufficient bandwidth, but has a phase response that distorts the beam signal in the time domain. We report on results from the design and implementation of an equalizer for the front end signal processing with correction for the pickup and cable responses. Using a model of the transfer functions for the pickups and the cabling, we determine a desired frequency response for the equalizer. Design for the circuitry, component value fitting is discussed as well as board construction and reduction of parasitic impedances. Finally, we show results from the measurement of an assembled equalizer, compare them with simulations and show beam signals from use at the SPS.

WECC04

Analysis of the Electro-optical Front End for the New 40 GHz Bunch Arrival Time Monitor System

laser, electron, timing, FEL

571

A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach
Uni HH, Hamburg, Germany
A. Angelovski, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
DESY, Hamburg, Germany
S. Schnepp
IFH, Zurich, Switzerland
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

The Free electron LASer in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAMs) which achieve a time resolution of less than 10 fs for bunch charges higher than 500 pC (1). In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With the current 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 (2) 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 pickup system also requires a new electro-optical frontend with a 40 GHz EOM. The theoretical limits of the time resolution depending on the RF signal at different bunch charges and on the jitter of the reference laser pulses where analyzed for the new EOM.
(1) M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany,2011, p. 365
(2) A. Angelovski, A. Kuhl et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p. 1177 and p. 1186

Slides WECC04 [12.560 MB]

THTA01

Beam Position Monitors for Circular Accelerators

impedance, coupling, resonance, closed-orbit

590

S. Hiramatsu
KEK, Ibaraki, Japan

The electrostatic induction type beam position monitors (BPMs) for circular accelerators such as proton synchrotrons and electron accumulation rings will be discussed. Discussions on the beam induced charge on the BPM pick-up electrodes, signal detection systems, and techniques of beam based alignment and beam based calibration will be given. For high beam current machines, the evaluation of the beam coupling impedance of BPM is an important issue to avoid the beam current limit by beam instabilities caused by BPM impedances. Another serious problem is the movement of BPMs by the thermal distortion of the beam pipe by high power synchrotron radiation. These problems will be also mentioned briefly.

Slides THTA01 [6.252 MB]