DIPAC2011 - List of Keywords (impedance)

Paper	Title	Other Keywords	Page
MOPD06	Capabilities and Performance of the LHC Schottky Monitors	pick-up, injection, emittance, proton	44
	M. Favier, T.B. Bogey, F. Caspers, O.R. Jones CERN, Geneva, Switzerland J. Cai, E.S.M. McCrory, R.J. Pasquinelli Fermilab, Batavia, USA A. Jansson ESS, Lund, Sweden
	The LHC Schottky system has been under commissioning since summer 2010. This non destructive observation relies on a slotted waveguide structure resonating at 4.8GHz. Four monitors, one for each plane of the two counter-rotating LHC beams, are used to measure the transverse Schottky sidebands Electronic gating allows selective bunch-by-bunch measurements, while a triple down-mixing scheme combined with heavy filtering gives an instantaneous dynamic range of over 100dB within a 20kHz bandwidth. Observations of both proton and lead ion Schottky spectra will be discussed along with a comparison of predicted and measured performance.
	Poster MOPD06 [3.484 MB]

MOPD13	Mode Selective Waveguide BPM	coupling, cavity, pick-up, simulation	65
	A. Lyapin JAI, Egham, Surrey, United Kingdom
	I propose a mode-selective waveguide Beam Position Monitor (BPM). It uses waveguide couplers arranged at the beampipe to create boundary conditions similar to those in slot-coupled cavity BPMs. This structure allows to couple to the differential waveguide mode co-propagating with the beam, and reject the usually much stronger monopole component of the field. As the full dynamic range of the processing electronics can be used for position measurements, and a waveguide is a native high-pass filter, such a BPM is expected to outperform stripline and button BPMs in terms of both spacial and time resolution. In this paper I give some details on the basic principle and the first simulation results and discuss possible ways of signal processing.
	Poster MOPD13 [3.052 MB]

MOPD18	Embedded Collimator Beam Position Monitors	vacuum, beam-losses, collimation, proton	80
	C.B. Boccard, A. Bertarelli, A. Dallocchio, M. Gasior, L. Gentini, A.A. Nosych CERN, Geneva, Switzerland
	The LHC collimation system is crucial for safe and reliable operation of proton beams with 350 MJ stored energy. Currently the collimator set-up is performed by observing beam losses when approaching the collimator jaws to the beam. For all 100 LHC movable collimators the procedure may take several hours and since it has to be repeated whenever the beam configuration changes significantly, the collimator setup has an important impact on the overall machine operation efficiency. To reduce the collimator setup time by two orders of magnitude the next generation of the LHC collimators will be equipped with button beam position monitors (BPMs) embedded into the collimator jaws. This paper describes the BPM design and presents prototype results obtained with beam in the CERN-SPS.
	Poster MOPD18 [1.729 MB]

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

MOPD27	A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI	pick-up, ion, electron, vacuum	107
	F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick GSI, Darmstadt, Germany Yu.A. Litvinov MPI-K, Heidelberg, Germany M.S. Sanjari IKF, Frankfurt am Main, Germany J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao IMP, Lanzhou, People's Republic of China
	A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD65	Sensitivity Optimization of the Standard Beam Current Monitors for XFEL and FLASH II	pick-up, monitoring, diagnostics, ion	197
	M. Werner, J. Lund-Nielsen, Re. Neumann, N. Wentowski DESY, Hamburg, Germany
	There is a tendency to operate 4th generation SASE driven light sources at very low charge in order to further shorten the pulse length. Therefore the operation range of XFEL and FLASH II was extended to a charge range of as low as 20 pC to 1 nC. For a reliable charge measurement down to 20 pC, a low noise design of the signal chain from the monitor head to the digitizing ADC is necessary. This paper describes the steps taken in order to increase the sensitivity and dynamic range of the monitors currently used in the FLASH accelerator, and the basic theoretical background will be explained. Finally, first results are presented.
	Poster MOPD65 [0.768 MB]

MOPD87	The LHC Beam Presence Flag System	controls, injection, monitoring, feedback	251
	M. Gasior, T.B. Bogey CERN, Geneva, Switzerland
	Before injecting any high intensity bunches into the LHC a circulating low intensity pilot bunch must be present to confirm the correct settings of the main machine parameters. For the 2010 LHC run the detection of this pilot beam was done with the beam current transformer system. To increase redundancy of this important safety function a dedicated beam presence flag system was designed, built and tested with beam to be used operationally in the 2011 run. In this system signals from four electrodes of a beam position monitor (BPM) are processed with separate channels, resulting in a quadruple system redundancy for either beam. Each system channel consists of an analogue front-end converting the BPM signals into two logic states, which are then transmitted optically to the machine protection and interlock systems. For safety reasons the system does not have any remote control or adjustable elements and its only inputs are the beam signals. This paper describes the new LHC beam presence flag system, in particular the analogue front-end based on diode peak detectors.
	Poster MOPD87 [8.200 MB]

MOPD91	Pulse-By-Pulse X-ray Beam Monitor Equipped with Microstripline Structure	electron, high-voltage, diagnostics, pick-up	260
	H. Aoyagi, S. Takahashi JASRI/SPring-8, Hyogo-ken, Japan H. Kitamura RIKEN/SPring-8, Hyogo, Japan
	Pulse-by-pulse measurement of X-ray beam is import issue for the 3rd generation light sources in order not only to stabilize X-ray beam in an experimental hutch but also to diagnose electron beam in a storage ring. A new pulse-by-pulse X-ray beam monitor equipped with microstripline structure has been developed. The detector head has the microstripline structure. The impedance of the detector head is matched to 50 ohm. Thermodynamics of the detector head is also well considered against severe heat load. The advantage of this monitor is that output signal is short and unipolar pulse, so front-end electronics can be simplified. The feasibility tests have been demonstrated at the X-ray beamline of SPring-8 in the term of (1) pulse intensity monitor, (2) pulse-by-pulse X-ray beam position monitor, and (3) the pulse-timing monitor. Then, we have improved the structure of the detector head in order to sophisticate the function as the pulse timing monitor. As a result, we successfully removed the ringing parts of output signal, and demonstrated that this monitor can be used as the timing monitor. We also describe a new scheme for beam diagnostics using this monitor.
	Poster MOPD91 [1.309 MB]

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

TUPD16	High Frequency Measurements of the Beam Position Monitors for the TBL Line of the CTF3 at CERN	bunching, pick-up, monitoring, simulation	335
	J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera-Navarrete, A. Faus-Golfe IFIC, Valencia, Spain B. Gimeno UVEG, Burjasot (Valencia), Spain
	Funding: Funding Agency: FPA2010-21456-C02-00 A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the 3rd CLIC Test Facility (CTF3) at CERN. Two different characterization tests, at low and high frequencies, were carried out on the BPS units: The low frequency test, in the beam pulse time scale (until 10ns/100MHz), determined the BPSs parameters directly related to the beam position monitoring and the high frequency test, reaching the microwave X-Ku bands around the beam bunching time scale (83ps/12GHz). In this paper we describe the results and methods used to obtain the longitudinal impedance in the frequency range of interest. This test is based on the S-parameters measurements of the propagating TEM mode in a matched coaxial waveguide, specifically designed for the BPS, which is able to emulate an ultra-relativistic electron beam.
	Poster TUPD16 [1.069 MB]

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

TUPD20	Pre-amplifier Impedance Matching for Cryogenic BPMs	cryogenics, vacuum, synchrotron, quadrupole	347
	P. Kowina, M. Freimuth, K. Gütlich, W. Kaufmann, H. Rödl, J. Wießmann GSI, Darmstadt, Germany N. Sobel, F. Völklein Hochschule RheinMain, Wiesbaden, Germany
	Beam Position Monitors (BPMs) for the FAIR fast-ramped super conducting synchrotron SIS-100 will be installed inside the cryostats of quadrupole magnets. This contribution focuses on the coupling path between BPM electrodes and low noise amplifiers installed outside the cryostat. Matching transformers (MT) meet well the requirements of reflection free signal transfer through the relative long lines without loading the capacitive BPM by 50 Ohm. Different transformers based on toroidal cores made out of Vitroperm-500F nanocrystalline were tested. The form of windings and circuit geometry were optimized to improve linearity allow for resonance-free transmission over a required frequency range from 0.1 MHz to 80 MHz. The MTs have to be balanced pair wise within 0.1 dB and the geometry of windings has to be mechanically stabilized using e.g. epoxy resin. A choice of different epoxy types and their suitability for cryogenic operation was tested in liquid Nitrogen and liquid Helium.
	Poster TUPD20 [0.655 MB]

TUPD55	Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN	vacuum, instrumentation, dipole, electron	431
	D. Egger EPFL, Lausanne, Switzerland A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca CERN, Geneva, Switzerland
	The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.
	Poster TUPD55 [0.959 MB]

TUPD70	Conceptual Design of a High Sensitive Versatile Schottky Sensor for the Collector Ring at FAIR	cavity, coupling, antiproton, storage-ring	470
	M. Hansli, R. Jakoby, A. Penirschke TU Darmstadt, Darmstadt, Germany W. Ackermann, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany W. Kaufmann GSI, Darmstadt, Germany
	Funding: Funded by the Federal Ministry of Education and Research (BMBF): 06DA90351 The FAIR (Facility for Antiproton and Ion Research) accelerator complex includes the Collector Ring CR, i.e. a dedicated storage ring for secondary particles, rare isotopes and antiprotons. The CR features three different modes of operation: pre-cooling of antiprotons at 3 GeV, pre-cooling of rare isotope beams at 740 MeV/u and an isochronous mode for mass measurements. For beam optimizations in all three modes a sensitive Schottky setup is required to monitor very low beam intensities down to single particles. In this paper the conceptual design of a longitudinal Schottky sensor based on a pillbox cavity with adjustable coupling and frequency tuning is presented. The basic measurement principles are depicted and a possible realization is discussed with emphasize on the special requirements of the CR operational modes. Full-wave simulations of the proposed sensor cavity allow for further optimizations.
	Poster TUPD70 [1.247 MB]

TUPD81	The Petra III Multibunch Feedback System	feedback, kicker, cavity, synchrotron	494
	J. Klute, K. Balewski, A. Delfs, H.T. Duhme, M. Ebert, Ru. Neumann, F. Obier DESY, Hamburg, Germany
	In order to fulfill the demands of a high brilliance synchrotron light source like PETRA III different feedback systems are required. The high brilliance is accomplished by high beam current of 100 mA and very small transverse emittances. The current in PETRA is limited by coupled bunch instabilities to rather low values and powerful longitudinal and transverse feedback systems are necessary to achieve the design current. A careful design of the feedback is required in order to avoid any kind of beam quality degradation such as beam blow up due to noise. Additional requirements on signal processing are: very high dynamic range, adaptive signal adjustment, very high sensitivity to beam oscillations, high resolution and very high bandwidth. This contribution will describe the most important components and their properties. Results of the feedback operation will be presented and discussed. The design current of 100mA has been achieved without the indication of emittance growth and the feedback has been operated reliably during the fast user period.

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

WEOC03	Dark Current Monitor for the European XFEL	simulation, solenoid, controls, FEL	572
	D. Lipka, W. Kleen, J. Lund-Nielsen, D. Nölle, S. Vilcins, V. Vogel DESY, Hamburg, Germany
	Dark current is produced due from field emission in the accelerator. This generates a radiation background in the tunnel which damages the electronics and activates components. To decrease the dark current different methods like kickers and collimators are used. To control the dark current level and measure and optimize the efficiency of dark current reduction dark current monitors are required. To measure the dark current a cavity was designed and built with the operation frequency of the accelerator. Here the small charge of the dark current present in every RF bucket induces and superimposes a field up to a measurable level. The cavity is proven at the PITZ facility. In addition to dark current levels down to 50 nA, the monitor allows for charge measurements resolution below pC, better than the Faraday cup. In addition the ratio of amplitudes from higher order monopole modes is a function of the bunch length. Measurements show the same trend of bunch length compared with a destructive streak camera method with comparable resolution. Therefore this monitor is able to measure bunch charge, dark current and bunch length in a non-destructive manner.
	Slides WEOC03 [0.935 MB]

Paper

Title

Other Keywords

Page

MOPD06

Capabilities and Performance of the LHC Schottky Monitors

pick-up, injection, emittance, proton

44

M. Favier, T.B. Bogey, F. Caspers, O.R. Jones
CERN, Geneva, Switzerland
J. Cai, E.S.M. McCrory, R.J. Pasquinelli
Fermilab, Batavia, USA
A. Jansson
ESS, Lund, Sweden

The LHC Schottky system has been under commissioning since summer 2010. This non destructive observation relies on a slotted waveguide structure resonating at 4.8GHz. Four monitors, one for each plane of the two counter-rotating LHC beams, are used to measure the transverse Schottky sidebands Electronic gating allows selective bunch-by-bunch measurements, while a triple down-mixing scheme combined with heavy filtering gives an instantaneous dynamic range of over 100dB within a 20kHz bandwidth. Observations of both proton and lead ion Schottky spectra will be discussed along with a comparison of predicted and measured performance.

Poster MOPD06 [3.484 MB]

MOPD13

Mode Selective Waveguide BPM

coupling, cavity, pick-up, simulation

65

A. Lyapin
JAI, Egham, Surrey, United Kingdom

I propose a mode-selective waveguide Beam Position Monitor (BPM). It uses waveguide couplers arranged at the beampipe to create boundary conditions similar to those in slot-coupled cavity BPMs. This structure allows to couple to the differential waveguide mode co-propagating with the beam, and reject the usually much stronger monopole component of the field. As the full dynamic range of the processing electronics can be used for position measurements, and a waveguide is a native high-pass filter, such a BPM is expected to outperform stripline and button BPMs in terms of both spacial and time resolution. In this paper I give some details on the basic principle and the first simulation results and discuss possible ways of signal processing.

Poster MOPD13 [3.052 MB]

MOPD18

Embedded Collimator Beam Position Monitors

vacuum, beam-losses, collimation, proton

80

C.B. Boccard, A. Bertarelli, A. Dallocchio, M. Gasior, L. Gentini, A.A. Nosych
CERN, Geneva, Switzerland

The LHC collimation system is crucial for safe and reliable operation of proton beams with 350 MJ stored energy. Currently the collimator set-up is performed by observing beam losses when approaching the collimator jaws to the beam. For all 100 LHC movable collimators the procedure may take several hours and since it has to be repeated whenever the beam configuration changes significantly, the collimator setup has an important impact on the overall machine operation efficiency. To reduce the collimator setup time by two orders of magnitude the next generation of the LHC collimators will be equipped with button beam position monitors (BPMs) embedded into the collimator jaws. This paper describes the BPM design and presents prototype results obtained with beam in the CERN-SPS.

Poster MOPD18 [1.729 MB]

MOPD21

Overview of the BPM System of the ESS-Bilbao

controls, EPICS, linac, LLRF

89

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

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

Poster MOPD21 [1.476 MB]

MOPD27

A Sensitive Resonant Schottky Pick-Up for the ESR Storage Ring at GSI

pick-up, ion, electron, vacuum

107

F. Nolden, P. Hülsmann, P. Moritz, C. Peschke, P. Petri, M. Steck, H. Weick
GSI, Darmstadt, Germany
Yu.A. Litvinov
MPI-K, Heidelberg, Germany
M.S. Sanjari
IKF, Frankfurt am Main, Germany
J.X. Wu, Y.D. Zang, S.H. Zhang, T.C. Zhao
IMP, Lanzhou, People's Republic of China

A cavity-like Schottky detector for the heavy ion storage ring ESR at GSI is presented. It works at resonant frequencies around 245 MHz, its loaded Q value is 511, and its loaded R/Q value is roughly 55 Ohms. It features both a very good sensitivity even for beams with single circulating ions and the possibility to take valuable spectra in short time. A few experiments with the new device are presented which show clearly that the device offers new experimental opportunities, both for accelerator diagnostics and nuclear physics experiments. A similar device will be built into the CSRe storage ring at IMP.

MOPD65

Sensitivity Optimization of the Standard Beam Current Monitors for XFEL and FLASH II

pick-up, monitoring, diagnostics, ion

197

M. Werner, J. Lund-Nielsen, Re. Neumann, N. Wentowski
DESY, Hamburg, Germany

There is a tendency to operate 4th generation SASE driven light sources at very low charge in order to further shorten the pulse length. Therefore the operation range of XFEL and FLASH II was extended to a charge range of as low as 20 pC to 1 nC. For a reliable charge measurement down to 20 pC, a low noise design of the signal chain from the monitor head to the digitizing ADC is necessary. This paper describes the steps taken in order to increase the sensitivity and dynamic range of the monitors currently used in the FLASH accelerator, and the basic theoretical background will be explained. Finally, first results are presented.

Poster MOPD65 [0.768 MB]

MOPD87

The LHC Beam Presence Flag System

controls, injection, monitoring, feedback

251

M. Gasior, T.B. Bogey
CERN, Geneva, Switzerland

Before injecting any high intensity bunches into the LHC a circulating low intensity pilot bunch must be present to confirm the correct settings of the main machine parameters. For the 2010 LHC run the detection of this pilot beam was done with the beam current transformer system. To increase redundancy of this important safety function a dedicated beam presence flag system was designed, built and tested with beam to be used operationally in the 2011 run. In this system signals from four electrodes of a beam position monitor (BPM) are processed with separate channels, resulting in a quadruple system redundancy for either beam. Each system channel consists of an analogue front-end converting the BPM signals into two logic states, which are then transmitted optically to the machine protection and interlock systems. For safety reasons the system does not have any remote control or adjustable elements and its only inputs are the beam signals. This paper describes the new LHC beam presence flag system, in particular the analogue front-end based on diode peak detectors.

Poster MOPD87 [8.200 MB]

MOPD91

Pulse-By-Pulse X-ray Beam Monitor Equipped with Microstripline Structure

electron, high-voltage, diagnostics, pick-up

260

H. Aoyagi, S. Takahashi
JASRI/SPring-8, Hyogo-ken, Japan
H. Kitamura
RIKEN/SPring-8, Hyogo, Japan

Pulse-by-pulse measurement of X-ray beam is import issue for the 3rd generation light sources in order not only to stabilize X-ray beam in an experimental hutch but also to diagnose electron beam in a storage ring. A new pulse-by-pulse X-ray beam monitor equipped with microstripline structure has been developed. The detector head has the microstripline structure. The impedance of the detector head is matched to 50 ohm. Thermodynamics of the detector head is also well considered against severe heat load. The advantage of this monitor is that output signal is short and unipolar pulse, so front-end electronics can be simplified. The feasibility tests have been demonstrated at the X-ray beamline of SPring-8 in the term of (1) pulse intensity monitor, (2) pulse-by-pulse X-ray beam position monitor, and (3) the pulse-timing monitor. Then, we have improved the structure of the detector head in order to sophisticate the function as the pulse timing monitor. As a result, we successfully removed the ringing parts of output signal, and demonstrated that this monitor can be used as the timing monitor. We also describe a new scheme for beam diagnostics using this monitor.

Poster MOPD91 [1.309 MB]

TUOA01

Beam Instrumentation in J-PARC

linac, feedback, proton, septum

275

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

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

Slides TUOA01 [22.777 MB]

TUPD16

High Frequency Measurements of the Beam Position Monitors for the TBL Line of the CTF3 at CERN

bunching, pick-up, monitoring, simulation

335

J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera-Navarrete, A. Faus-Golfe
IFIC, Valencia, Spain
B. Gimeno
UVEG, Burjasot (Valencia), Spain

Funding: Funding Agency: FPA2010-21456-C02-00
A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the 3rd CLIC Test Facility (CTF3) at CERN. Two different characterization tests, at low and high frequencies, were carried out on the BPS units: The low frequency test, in the beam pulse time scale (until 10ns/100MHz), determined the BPSs parameters directly related to the beam position monitoring and the high frequency test, reaching the microwave X-Ku bands around the beam bunching time scale (83ps/12GHz). In this paper we describe the results and methods used to obtain the longitudinal impedance in the frequency range of interest. This test is based on the S-parameters measurements of the propagating TEM mode in a matched coaxial waveguide, specifically designed for the BPS, which is able to emulate an ultra-relativistic electron beam.

Poster TUPD16 [1.069 MB]

TUPD18

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

linac, cavity, ion, simulation

341

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

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

TUPD20

Pre-amplifier Impedance Matching for Cryogenic BPMs

cryogenics, vacuum, synchrotron, quadrupole

347

P. Kowina, M. Freimuth, K. Gütlich, W. Kaufmann, H. Rödl, J. Wießmann
GSI, Darmstadt, Germany
N. Sobel, F. Völklein
Hochschule RheinMain, Wiesbaden, Germany

Beam Position Monitors (BPMs) for the FAIR fast-ramped super conducting synchrotron SIS-100 will be installed inside the cryostats of quadrupole magnets. This contribution focuses on the coupling path between BPM electrodes and low noise amplifiers installed outside the cryostat. Matching transformers (MT) meet well the requirements of reflection free signal transfer through the relative long lines without loading the capacitive BPM by 50 Ohm. Different transformers based on toroidal cores made out of Vitroperm-500F nanocrystalline were tested. The form of windings and circuit geometry were optimized to improve linearity allow for resonance-free transmission over a required frequency range from 0.1 MHz to 80 MHz. The MTs have to be balanced pair wise within 0.1 dB and the geometry of windings has to be mechanically stabilized using e.g. epoxy resin. A choice of different epoxy types and their suitability for cryogenic operation was tested in liquid Nitrogen and liquid Helium.

Poster TUPD20 [0.655 MB]

TUPD55

Performance of the Time Resolved Spectrometer for the 5 MeV Photo-Injector PHIN

vacuum, instrumentation, dipole, electron

431

D. Egger
EPFL, Lausanne, Switzerland
A.E. Dabrowski, M. Divall Csatari, S. Döbert, D. Egger, T. Lefèvre, O. Mete, M. Olvegård, M. Petrarca
CERN, Geneva, Switzerland

The PHIN photo-injector test facility is being commissioned at CERN in order to fulfill the beam parameter requirements for the 3rd CLIC Test Facility (CTF3), which includes the production of a 3.5 Amp stable beam, bunched at 1.5 GHz with a relative energy spread of less than 1%. A 90° spectrometer is instrumented with an OTR screen coupled to a gated intensified camera, followed by a segmented beam dump for time resolved energy measurements. The following paper describes the transverse and temporal resolution of the instrumentation with an outlook towards single-bunch energy measurements.

Poster TUPD55 [0.959 MB]

TUPD70

Conceptual Design of a High Sensitive Versatile Schottky Sensor for the Collector Ring at FAIR

cavity, coupling, antiproton, storage-ring

470

M. Hansli, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
W. Ackermann, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
W. Kaufmann
GSI, Darmstadt, Germany

Funding: Funded by the Federal Ministry of Education and Research (BMBF): 06DA90351
The FAIR (Facility for Antiproton and Ion Research) accelerator complex includes the Collector Ring CR, i.e. a dedicated storage ring for secondary particles, rare isotopes and antiprotons. The CR features three different modes of operation: pre-cooling of antiprotons at 3 GeV, pre-cooling of rare isotope beams at 740 MeV/u and an isochronous mode for mass measurements. For beam optimizations in all three modes a sensitive Schottky setup is required to monitor very low beam intensities down to single particles. In this paper the conceptual design of a longitudinal Schottky sensor based on a pillbox cavity with adjustable coupling and frequency tuning is presented. The basic measurement principles are depicted and a possible realization is discussed with emphasize on the special requirements of the CR operational modes. Full-wave simulations of the proposed sensor cavity allow for further optimizations.

Poster TUPD70 [1.247 MB]

TUPD81

The Petra III Multibunch Feedback System

feedback, kicker, cavity, synchrotron

494

J. Klute, K. Balewski, A. Delfs, H.T. Duhme, M. Ebert, Ru. Neumann, F. Obier
DESY, Hamburg, Germany

In order to fulfill the demands of a high brilliance synchrotron light source like PETRA III different feedback systems are required. The high brilliance is accomplished by high beam current of 100 mA and very small transverse emittances. The current in PETRA is limited by coupled bunch instabilities to rather low values and powerful longitudinal and transverse feedback systems are necessary to achieve the design current. A careful design of the feedback is required in order to avoid any kind of beam quality degradation such as beam blow up due to noise. Additional requirements on signal processing are: very high dynamic range, adaptive signal adjustment, very high sensitivity to beam oscillations, high resolution and very high bandwidth. This contribution will describe the most important components and their properties. Results of the feedback operation will be presented and discussed. The design current of 100mA has been achieved without the indication of emittance growth and the feedback has been operated reliably during the fast user period.

WEOC01

Beam Charge Measurements

vacuum, coupling, pick-up, linac

564

D. Belohrad
CERN, Geneva, Switzerland

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

Slides WEOC01 [5.738 MB]

WEOC03

Dark Current Monitor for the European XFEL

simulation, solenoid, controls, FEL

572

D. Lipka, W. Kleen, J. Lund-Nielsen, D. Nölle, S. Vilcins, V. Vogel
DESY, Hamburg, Germany

Dark current is produced due from field emission in the accelerator. This generates a radiation background in the tunnel which damages the electronics and activates components. To decrease the dark current different methods like kickers and collimators are used. To control the dark current level and measure and optimize the efficiency of dark current reduction dark current monitors are required. To measure the dark current a cavity was designed and built with the operation frequency of the accelerator. Here the small charge of the dark current present in every RF bucket induces and superimposes a field up to a measurable level. The cavity is proven at the PITZ facility. In addition to dark current levels down to 50 nA, the monitor allows for charge measurements resolution below pC, better than the Faraday cup. In addition the ratio of amplitudes from higher order monopole modes is a function of the bunch length. Measurements show the same trend of bunch length compared with a destructive streak camera method with comparable resolution. Therefore this monitor is able to measure bunch charge, dark current and bunch length in a non-destructive manner.

Slides WEOC03 [0.935 MB]