IBIC2012 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPA42	Measurements of Martin-Puplett Interferometer Limitations using Blackbody Source	detector, radiation, FEL, experiment	153
	P.E. Evtushenko, J.M. Klopf JLAB, Newport News, Virginia, USA
	Frequency domain measurements with Martin-Puplett interferometer is one of a few techniques capable of bunch length measurements at the level of ~ 100 fs. As the bunch length becomes shorter, it is important to know and be able to measure the limitations of the instrument in terms of shortest measurable bunch length. In this paper we describe experiment of using blackbody source with the modified Matrin-Puplett interferometer that is routinely used for bunch length measurements at the JLab FEL, as a way to estimate the shortest, measurable with the device, bunch. The limitation comes from high frequency cut-off of the presently used wire-grid polarizer and is estimated to be 50 fs RMS. The measurements are made with the same Golay cell detector that is used for beam measurements. We demonstrate that, even though the blackbody source is many orders of magnitude less bright than the coherent transition or synchrotron radiation, it can be used for the measurements and gives a very good signal to noise ratio in a combination with lock-in detection. We also compare the measurements made in air and in vacuum to show the very strong effect of the atmospheric absorption.

MOPB51	Beam Monitors of NIRS Fast Scanning System for Particle Therapy	ion, controls, cathode, monitoring	182
	T. Furukawa, Y. Hara, T. Inaniwa, K. Katagiri, K. Mizushima, K. Noda, S. Sato, T. Shirai, E. Takeshita NIRS, Chiba-shi, Japan
	At National Institute of Radiological Sciences, more than 6500 patients have been successfully treated by carbon beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with three-dimensional pencil beam scanning irradiation system. The commissioning of NIRS fast scanning system installed into the new facility was started in September 2010, and the treatment with scanned ion beam was started in May 2011. In the scanning delivery system, beam monitors are some of the most important components. In order to measure and control the dose of each spot, the main and the sub ionization chambers are placed separately as flux monitors. For monitoring of the scanned beam position, a beam position monitor, which is multi-wire proportional chamber, is installed just downstream from the flux monitors. This monitor can output not only the beam position but also the 2D fluence distribution using dynamic fast convolution algorithm. In this paper, the design and the commissioning of these monitors are described.

MOPB72	First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line	detector, extraction, optics, coupling	237
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi KEK, Ibaraki, Japan G.S. Varner University of Hawaii, Honolulu, HI, USA
	Funding: Kakenhi The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented.

MOPB77	Adjustable Optics for a Non-destructive Beam Profile Monitor based on Scintillation of Residual Gas	operation, electron, injection, detector	253
	K. Reimers, V. Kamerdzhiev, A. Pernizki FZJ, Jülich, Germany
	The scintillation profile monitor (SPM) is being developed at COSY in addition to the existing ionisation profile monitor (IPM). Contrary to the IPM it does not require in-vacuum components, making it a robust and inexpensive instrument. The SPM is suitable for high intensity operation rather than operation with low intensity polarised beams. A multichannel PMT is used to detect scintillation light. The rate of detectable scintillation events is about three orders of magnitude lower compared to the rate of ionisation events. To boost the photon yield, small amounts of nitrogen are injected into the SPM vacuum chamber. An adjustable light focusing system is being built to optimise the SPM performance for different machine operation modes. The new system allows using a variety of optical components ranging from single lenses to high-grade camera objectives. Cylindrical lenses are considered to further boost the sensitivity by better fitting the beam image to the detector geometry. The latest experimental results and the new design of the optical system are presented.

MOPB79	Design of a High-precision Fast Wire Scanner for the SPS at CERN	operation, booster, laser, acceleration	259
	R. Veness, N. Chritin, B. Dehning, J. Emery, J.F. Herranz Alvarez, M. Koujili, S. Samuelsson, J.L. Sirvent Blasco CERN, Geneva, Switzerland
	Studies are going on of a new wire scanner concept. All moving parts are inside the beam vacuum and it is specified for use in all the machines across the CERN accelerator complex. Key components have been developed and tested. Work is now focussing on the installation of a prototype for test in the Super Proton Synchrotron (SPS) accelerator. This article presents the specification of the device and constraints on the design for integration in the different accelerators at CERN. The design issues of the mechanical components are discussed and optimisation work shown. Finally, the prototype design, integrating the several components into the vacuum tank is presented.

MOPB81	Residual Gas Ionization Profile Monitors in J-PARC Slow-extraction Beam Line	electron, proton, extraction, radiation	267
	Y. Sato, A. Agari, E. Hirose, M. Ieiri, Y. Katoh, M. Minakawa, R. Muto, M. Naruki, S. Sawada, Y. Shirakabe, Y. Suzuki, H. Takahashi, M. Takasaki, K.H. Tanaka, A. Toyoda, H. Watanabe, Y. Yamanoi KEK, Tsukuba, Japan H. Noumi RCNP, Osaka, Japan
	Residual gas ionization profile monitors (RGIPMs) working in 1 Pa pressure have been developed for high-intensity proton beam (maximum: 50GeV-15uA) at J-PARC slow-extraction beam line. The transverse beam profiles are measured by collecting electrons produced by ionization of 1 Pa residual gas. The electrons are guided to the segmented electrode with a uniform electrostatic field applied in the gap. A uniform magnetic field is applied parallel to the electric field to reduce diffusion of electrons travelling to the electrodes. Typical spatial resolution of the RGIPMs with a 10 cm gap, a 10 V/cm electrostatic field, and a 400 gauss magnetic field at center is 0.5 mm. The collected charge is integrated during every extraction period (typically 2 second in 6 second accelerator cycle). Subtracting background distributions measured during off-beam period, profile distributions are measured clearly. The 14 RGIPMs installed in the slow-extraction beam line are working stably for the 30 GeV-0.46 uA proton beam at current maximum. In this contribution, detailed specifications and performance of the present RGIPMs will be reported.

MOPB82	Bunch-Compressor Transverse Profile Monitors of the SwissFEL Injector Test Facility	electron, operation, laser, undulator	271
	G.L. Orlandi, M. Aiba, S. Bettoni, B. Beutner, H. Brands, R. Ischebeck, P. Peier, E. Prat, T. Schietinger, V. Schlott, V.G. Thominet PSI, Villigen PSI, Switzerland C. Gerth DESY, Hamburg, Germany
	The 250 MeV SwissFEL Injector Test Facility (SITF) is the test bed of the future 5.7 GeV SwissFEL linac that will drive a coherent FEL light source in the wavelength range 7-0.7 and 0.7-0.1 nm. Aim of the SITF is to demonstrate the technical feasibility of producing and measuring 10 or 200pC electron bunches with normalized emittance down to 0.25 μm. A further goal is to demonstrate that the electron beam quality is preserved in the acceleration process, in the X-Band linearizer and the magnetic compression from about 10 ps down to 200 fs. The SITF movable magnetic bunch-compressor is equipped with several CCD/CMOS cameras for monitoring the beam transverse profile and determining the beam energy spread: a Ce:YAG screen and an OTR screen camera at the mid-point of the bunch compressor and a SR camera imaging in the visible the Synchrotron Radiation emitted by the electron beam crossing the third dipole. Results on the commissioning of such instrumentations, in particular in the low charge limit, and measurements of the beam energy spread vs. the compression factor will be presented.

TUTA02	BPM Electrode and High Power Feedthrough - Special Topics in Wideband Feedthrough	simulation, impedance, kicker, linac	297
	M. Tobiyama KEK, Ibaraki, Japan
	Since most of the beam in accelerator runs in the vacuum chamber made of metal, it is needed to have 'feedthrough' to get or to put the RF signal from or to beam. For example, we can get the beam signal by using button-type electrode which have electrical isolation material to seal the vacuum. Now, many types of vacuum feedthrough with coaxial structure are available commercially. Nevertheless, it is meaningful to understand the design principle of the feedthough needed for the beam instrumentation, especially for short bunch length, high beam current machine. I will show the design method of the feedthrough such as BPM electrodes or high power feedthroughs using 3D EM-codes such as HFSS or GdfidL based on several examples developed for SuperKEKB accelerators.
	Slides TUTA02 [6.806 MB]

TUIC02	Direct Observation of the Dust-trapping Phenomenon	electron, ion, high-voltage, experiment	315
	Y. Tanimoto KEK, Ibaraki, Japan
	Dust trapping has long been an unwelcome and mysterious phenomenon in electron storage rings. As it leads to a sudden decrease in beam lifetime, dust trapping has been a perpetual nuisance at the Photon Factory Advanced Ring (PF-AR) since its beginning in the 1980s. However, during recent research on dust trapping at the PF-AR, video cameras serendipitously captured the culprit behind this phenomenon; the cameras recorded a luminous micro-particle trapped in the electron beam, just as if a shooting star were traveling in the beam tube. In the successive research, supersensitive cameras repeatedly observed trapped dust particles, and revealed that they behaved differently under different conditions. My presentation will summarize these experimental results, as well as long-term statistics supporting present dust-trapping theories.
	Slides TUIC02 [8.200 MB]

TUPA08	Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC	experiment, luminosity, data-acquisition, background	344
	M.E. Castro Carballo DESY Zeuthen, Zeuthen, Germany
	The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA10	Optical-Fiber Beam Loss Monitor for the KEK Photon Factory	injection, electron, storage-ring, kicker	351
	T. Obina, Y. Yano KEK, Ibaraki, Japan
	Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

TUPA15	Beam Postion Monitor for Energy Recovery Linac	pick-up, linac, 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.

TUPA37	FPGA Based Fast Orbit Feedback System for the Australian Synchrotron	feedback, FPGA, fibre-optics, sextupole	437
	Y.E. Tan, T.D. Cornall, S.A. Griffiths, S. Murphy, E. Vettoor ASCo, Clayton, Victoria, Australia
	An initial design for a Fast Global Orbit Feedback System based on FPGAs has been proposed for the Australian Synchrotron Light Source (ASLS). The design uses a central processor (Xilinx Virtex 6) for all the computations and fast optical connections to distribute the computed data to corrector magnet power supplies. The network topology consists of two fibre optic rings. The first ring is used by the Libera Electron's to aggregate the beam position data at 10 kHz using Instrumentation Technologies' Grouping algorithm. The second ring is used to transmit the computed data. The cycle frequency of the feedback is 10 kHz with a targeted total latency of under 350 us. We shall give an overview of the design goals and discuss the merits of the current implementation. We shall also present the measured bandwidth of the stainless steel vacuum chamber and test results from initial prototyping work.

TUPA43	First Operation of the Electro-optical Sampling Diagnostics of the FERMI@Elettra FEL	laser, electron, FEL, alignment	449
	M. Veronese, A. Abrami, E. Allaria, M. Bossi, M.B. Danailov, M. Ferianis, L. Fröhlich, S. Grulja, M. Predonzani, F. Rossi, G. Scalamera, C. Spezzani, M. Trovò, M. Tudor Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The FERMI@Elettra seeded FEL has demanding specifications in terms of longitudinal properties of the electron beam. Several diagnostics are installed along the linac. At the entrance of the FEL1 undulator chain an electro optical sampling (EOS) station based on the spatial encoding scheme is installed. The EOS provides both time jitter and longitudinal profile measurements in a non-destructive way. The layout of this system is described and the first operational measurement results obtained are reported. The paper includes also the capability of this diagnostics to perform the temporal coarse alignment of the seed laser to the electron beam. Finally a discussion on the future developments foreseen for this system is given.

TUPB53	Abort Diagnostics and Analysis during KEKB Operation	operation, cavity, hardware, detector	477
	H. Ikeda, J.W. Flanagan, T. Furuya, M. Tobiyama KEK, Ibaraki, Japan M. Tanaka Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	KEKB has stopped since June 2010 for upgrading the luminosity 40 times, i.e. SuperKEKB. During the operation of 11 years, a pair of controlled beam abort systems worked more than 10000 times to protect the hardware components of KEKB accelerator and the detector against the high intensity beams of LER and HER. Optimization of the abort trigger was necessary to balance efficient operation with the safety of the hardware. Therefore, we analyzed one-by-one all of the aborts, and continually adjusted the abort system. The diagnostic system was based on a high-sampling-rate data logger that recorded beam currents, RF signals and beam loss monitor signals. The beam oscillation signals, vacuum pressure and detector dose rate were also examined. This paper describes the typical abort causes, optimizations of abort levels, and abort statistics over approximately eight years after having arrived at high beam current operation.

TUPB64	Methods to Reduce the System Error for High Power MSSW Emittance Meter	emittance, ion, ion-source, electron	496
	S.X. Peng, J. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Y. Xu, Z.X. Yuan, J. Zhao PKU, Beijing, People's Republic of China
	Recently a new Multi-Slit Single-Wire (MSSW) type high power beam emittance meter named as HIBEMU-5 has developed in Peking University (PKU). Compared to previous MSSW devices, HIBEMU-5 greatly reduced the system error from 16.4% to 3.7% by specific designs to solve the incomplete short-slit sampling and fixed slit-wire distance. The problems of previous PKU devices are analyzed in part one. In part two, we describe the specific updating methods to solve its short-slit disadvantage by re-designing a longer-slit board with sufficient cooling, detail the mechanical scheme of changing the slit-wire distance for different beam divergence. The commissioning results given at part three prove that this new long slits design is successful to complete the beam sampling without being distorted by high power H⁺ beam. And the movable wire cup is able to locate the best measurement position for different beam focusing.

WECD01	Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program	detector, positron, optics, electron	585
	N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad CLASSE, Ithaca, New York, USA J.W. Flanagan KEK, Ibaraki, Japan
	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 CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x10⁹ to 1x10¹¹ particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources.
	Slides WECD01 [3.480 MB]

THCB02	Twisting Wire Scanner	feedback, software, controls, monitoring	607
	V. Gharibyan, A. Delfs, I. Krouptchenkov, D. Nölle, H. Tiessen, M. Werner, K. Wittenburg DESY, Hamburg, Germany
	A new type of 'two-in-one' wire scanner is proposed. Recent advances in linear motors' technology make it possible to combine translational and rotational movements. This will allow to scan the beam in two perpendicular directions using a single driving motor and a special fork attached to it. Vertical or horizontal mounting will help to escape problems associated with the 45 deg scanners. Test results of the translational part with linear motors will be presented.
	Slides THCB02 [5.591 MB]

Paper

Title

Other Keywords

Page

MOPA42

Measurements of Martin-Puplett Interferometer Limitations using Blackbody Source

detector, radiation, FEL, experiment

153

P.E. Evtushenko, J.M. Klopf
JLAB, Newport News, Virginia, USA

Frequency domain measurements with Martin-Puplett interferometer is one of a few techniques capable of bunch length measurements at the level of ~ 100 fs. As the bunch length becomes shorter, it is important to know and be able to measure the limitations of the instrument in terms of shortest measurable bunch length. In this paper we describe experiment of using blackbody source with the modified Matrin-Puplett interferometer that is routinely used for bunch length measurements at the JLab FEL, as a way to estimate the shortest, measurable with the device, bunch. The limitation comes from high frequency cut-off of the presently used wire-grid polarizer and is estimated to be 50 fs RMS. The measurements are made with the same Golay cell detector that is used for beam measurements. We demonstrate that, even though the blackbody source is many orders of magnitude less bright than the coherent transition or synchrotron radiation, it can be used for the measurements and gives a very good signal to noise ratio in a combination with lock-in detection. We also compare the measurements made in air and in vacuum to show the very strong effect of the atmospheric absorption.

MOPB51

Beam Monitors of NIRS Fast Scanning System for Particle Therapy

ion, controls, cathode, monitoring

182

T. Furukawa, Y. Hara, T. Inaniwa, K. Katagiri, K. Mizushima, K. Noda, S. Sato, T. Shirai, E. Takeshita
NIRS, Chiba-shi, Japan

At National Institute of Radiological Sciences, more than 6500 patients have been successfully treated by carbon beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with three-dimensional pencil beam scanning irradiation system. The commissioning of NIRS fast scanning system installed into the new facility was started in September 2010, and the treatment with scanned ion beam was started in May 2011. In the scanning delivery system, beam monitors are some of the most important components. In order to measure and control the dose of each spot, the main and the sub ionization chambers are placed separately as flux monitors. For monitoring of the scanned beam position, a beam position monitor, which is multi-wire proportional chamber, is installed just downstream from the flux monitors. This monitor can output not only the beam position but also the 2D fluence distribution using dynamic fast convolution algorithm. In this paper, the design and the commissioning of these monitors are described.

MOPB72

First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line

detector, extraction, optics, coupling

237

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi
KEK, Ibaraki, Japan
G.S. Varner
University of Hawaii, Honolulu, HI, USA

Funding: Kakenhi
The ATF2 extraction line is used as a test-bed for technologies needed for the ILC final-focus region. An x-ray extraction beam line has been constructed at the final upstream bend before the extraction line straight section, for development and testing of optics and readout systems for a coded aperture-based imaging system. The x-ray monitor is expected to eventually be able to measure single-shot vertical bunch sizes down to a few microns in size at its source location in the ATF2 extraction line. Preliminary scanned measurements have been made with beams in the ~15 micron range, and it is planned to make more measurements with further-tuned beam, and with fast read-out electronics. The details of the layout, expected performance, and preliminary measurement results will be presented.

MOPB77

Adjustable Optics for a Non-destructive Beam Profile Monitor based on Scintillation of Residual Gas

operation, electron, injection, detector

253

K. Reimers, V. Kamerdzhiev, A. Pernizki
FZJ, Jülich, Germany

The scintillation profile monitor (SPM) is being developed at COSY in addition to the existing ionisation profile monitor (IPM). Contrary to the IPM it does not require in-vacuum components, making it a robust and inexpensive instrument. The SPM is suitable for high intensity operation rather than operation with low intensity polarised beams. A multichannel PMT is used to detect scintillation light. The rate of detectable scintillation events is about three orders of magnitude lower compared to the rate of ionisation events. To boost the photon yield, small amounts of nitrogen are injected into the SPM vacuum chamber. An adjustable light focusing system is being built to optimise the SPM performance for different machine operation modes. The new system allows using a variety of optical components ranging from single lenses to high-grade camera objectives. Cylindrical lenses are considered to further boost the sensitivity by better fitting the beam image to the detector geometry. The latest experimental results and the new design of the optical system are presented.

MOPB79

Design of a High-precision Fast Wire Scanner for the SPS at CERN

operation, booster, laser, acceleration

259

R. Veness, N. Chritin, B. Dehning, J. Emery, J.F. Herranz Alvarez, M. Koujili, S. Samuelsson, J.L. Sirvent Blasco
CERN, Geneva, Switzerland

Studies are going on of a new wire scanner concept. All moving parts are inside the beam vacuum and it is specified for use in all the machines across the CERN accelerator complex. Key components have been developed and tested. Work is now focussing on the installation of a prototype for test in the Super Proton Synchrotron (SPS) accelerator. This article presents the specification of the device and constraints on the design for integration in the different accelerators at CERN. The design issues of the mechanical components are discussed and optimisation work shown. Finally, the prototype design, integrating the several components into the vacuum tank is presented.

MOPB81

Residual Gas Ionization Profile Monitors in J-PARC Slow-extraction Beam Line

electron, proton, extraction, radiation

267

Y. Sato, A. Agari, E. Hirose, M. Ieiri, Y. Katoh, M. Minakawa, R. Muto, M. Naruki, S. Sawada, Y. Shirakabe, Y. Suzuki, H. Takahashi, M. Takasaki, K.H. Tanaka, A. Toyoda, H. Watanabe, Y. Yamanoi
KEK, Tsukuba, Japan
H. Noumi
RCNP, Osaka, Japan

Residual gas ionization profile monitors (RGIPMs) working in 1 Pa pressure have been developed for high-intensity proton beam (maximum: 50GeV-15uA) at J-PARC slow-extraction beam line. The transverse beam profiles are measured by collecting electrons produced by ionization of 1 Pa residual gas. The electrons are guided to the segmented electrode with a uniform electrostatic field applied in the gap. A uniform magnetic field is applied parallel to the electric field to reduce diffusion of electrons travelling to the electrodes. Typical spatial resolution of the RGIPMs with a 10 cm gap, a 10 V/cm electrostatic field, and a 400 gauss magnetic field at center is 0.5 mm. The collected charge is integrated during every extraction period (typically 2 second in 6 second accelerator cycle). Subtracting background distributions measured during off-beam period, profile distributions are measured clearly. The 14 RGIPMs installed in the slow-extraction beam line are working stably for the 30 GeV-0.46 uA proton beam at current maximum. In this contribution, detailed specifications and performance of the present RGIPMs will be reported.

MOPB82

Bunch-Compressor Transverse Profile Monitors of the SwissFEL Injector Test Facility

electron, operation, laser, undulator

271

G.L. Orlandi, M. Aiba, S. Bettoni, B. Beutner, H. Brands, R. Ischebeck, P. Peier, E. Prat, T. Schietinger, V. Schlott, V.G. Thominet
PSI, Villigen PSI, Switzerland
C. Gerth
DESY, Hamburg, Germany

The 250 MeV SwissFEL Injector Test Facility (SITF) is the test bed of the future 5.7 GeV SwissFEL linac that will drive a coherent FEL light source in the wavelength range 7-0.7 and 0.7-0.1 nm. Aim of the SITF is to demonstrate the technical feasibility of producing and measuring 10 or 200pC electron bunches with normalized emittance down to 0.25 μm. A further goal is to demonstrate that the electron beam quality is preserved in the acceleration process, in the X-Band linearizer and the magnetic compression from about 10 ps down to 200 fs. The SITF movable magnetic bunch-compressor is equipped with several CCD/CMOS cameras for monitoring the beam transverse profile and determining the beam energy spread: a Ce:YAG screen and an OTR screen camera at the mid-point of the bunch compressor and a SR camera imaging in the visible the Synchrotron Radiation emitted by the electron beam crossing the third dipole. Results on the commissioning of such instrumentations, in particular in the low charge limit, and measurements of the beam energy spread vs. the compression factor will be presented.

TUTA02

BPM Electrode and High Power Feedthrough - Special Topics in Wideband Feedthrough

simulation, impedance, kicker, linac

297

M. Tobiyama
KEK, Ibaraki, Japan

Since most of the beam in accelerator runs in the vacuum chamber made of metal, it is needed to have 'feedthrough' to get or to put the RF signal from or to beam. For example, we can get the beam signal by using button-type electrode which have electrical isolation material to seal the vacuum. Now, many types of vacuum feedthrough with coaxial structure are available commercially. Nevertheless, it is meaningful to understand the design principle of the feedthough needed for the beam instrumentation, especially for short bunch length, high beam current machine. I will show the design method of the feedthrough such as BPM electrodes or high power feedthroughs using 3D EM-codes such as HFSS or GdfidL based on several examples developed for SuperKEKB accelerators.

Slides TUTA02 [6.806 MB]

TUIC02

Direct Observation of the Dust-trapping Phenomenon

electron, ion, high-voltage, experiment

315

Y. Tanimoto
KEK, Ibaraki, Japan

Dust trapping has long been an unwelcome and mysterious phenomenon in electron storage rings. As it leads to a sudden decrease in beam lifetime, dust trapping has been a perpetual nuisance at the Photon Factory Advanced Ring (PF-AR) since its beginning in the 1980s. However, during recent research on dust trapping at the PF-AR, video cameras serendipitously captured the culprit behind this phenomenon; the cameras recorded a luminous micro-particle trapped in the electron beam, just as if a shooting star were traveling in the beam tube. In the successive research, supersensitive cameras repeatedly observed trapped dust particles, and revealed that they behaved differently under different conditions. My presentation will summarize these experimental results, as well as long-term statistics supporting present dust-trapping theories.

Slides TUIC02 [8.200 MB]

TUPA08

Application of Single Crystal Diamonds (scCVD) as Beam Conditions Monitors at LHC

experiment, luminosity, data-acquisition, background

344

M.E. Castro Carballo
DESY Zeuthen, Zeuthen, Germany

The properties of the single-crystal diamond (scCVD): radiation hardness, low leakage current and fast signal, make it suitable for use as a particle detector in areas of high radiation dose. The Beam Conditions and Radiation Monitoring system (BRM) of the CMS experiment has a monitor (BCM1F) consisting of 4 modules located 1.8 m away from the interaction point, on both sides. Each module contains a sensor, radiation hard FEE and optical transmission of the signal. It counts single particles of beam halo, beam-gas, machine induced background, and collision products. The BRM protects CMS from high beam losses and provides feedback to the LHC and CMS on the beam conditions. The BCM1F sub-detector is very helpful as it is able to provide different background information together with luminosity correlations. Additional scCVD sensors are being installed in the LHC ring to be used as BLMs. The new BLM system (BCM1F4LHC) will be composed of 8 diamonds in points likely to suffer from beam losses. Nowadays, four sensors deliver information of hit rates that are correlated to the existing BLMs. A characterization of both BCM1F systems is presented.

TUPA10

Optical-Fiber Beam Loss Monitor for the KEK Photon Factory

injection, electron, storage-ring, kicker

351

T. Obina, Y. Yano
KEK, Ibaraki, Japan

Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.

TUPA15

Beam Postion Monitor for Energy Recovery Linac

pick-up, linac, 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.

TUPA37

FPGA Based Fast Orbit Feedback System for the Australian Synchrotron

feedback, FPGA, fibre-optics, sextupole

437

Y.E. Tan, T.D. Cornall, S.A. Griffiths, S. Murphy, E. Vettoor
ASCo, Clayton, Victoria, Australia

An initial design for a Fast Global Orbit Feedback System based on FPGAs has been proposed for the Australian Synchrotron Light Source (ASLS). The design uses a central processor (Xilinx Virtex 6) for all the computations and fast optical connections to distribute the computed data to corrector magnet power supplies. The network topology consists of two fibre optic rings. The first ring is used by the Libera Electron's to aggregate the beam position data at 10 kHz using Instrumentation Technologies' Grouping algorithm. The second ring is used to transmit the computed data. The cycle frequency of the feedback is 10 kHz with a targeted total latency of under 350 us. We shall give an overview of the design goals and discuss the merits of the current implementation. We shall also present the measured bandwidth of the stainless steel vacuum chamber and test results from initial prototyping work.

TUPA43

First Operation of the Electro-optical Sampling Diagnostics of the FERMI@Elettra FEL

laser, electron, FEL, alignment

449

M. Veronese, A. Abrami, E. Allaria, M. Bossi, M.B. Danailov, M. Ferianis, L. Fröhlich, S. Grulja, M. Predonzani, F. Rossi, G. Scalamera, C. Spezzani, M. Trovò, M. Tudor
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The FERMI@Elettra seeded FEL has demanding specifications in terms of longitudinal properties of the electron beam. Several diagnostics are installed along the linac. At the entrance of the FEL1 undulator chain an electro optical sampling (EOS) station based on the spatial encoding scheme is installed. The EOS provides both time jitter and longitudinal profile measurements in a non-destructive way. The layout of this system is described and the first operational measurement results obtained are reported. The paper includes also the capability of this diagnostics to perform the temporal coarse alignment of the seed laser to the electron beam. Finally a discussion on the future developments foreseen for this system is given.

TUPB53

Abort Diagnostics and Analysis during KEKB Operation

operation, cavity, hardware, detector

477

H. Ikeda, J.W. Flanagan, T. Furuya, M. Tobiyama
KEK, Ibaraki, Japan
M. Tanaka
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

KEKB has stopped since June 2010 for upgrading the luminosity 40 times, i.e. SuperKEKB. During the operation of 11 years, a pair of controlled beam abort systems worked more than 10000 times to protect the hardware components of KEKB accelerator and the detector against the high intensity beams of LER and HER. Optimization of the abort trigger was necessary to balance efficient operation with the safety of the hardware. Therefore, we analyzed one-by-one all of the aborts, and continually adjusted the abort system. The diagnostic system was based on a high-sampling-rate data logger that recorded beam currents, RF signals and beam loss monitor signals. The beam oscillation signals, vacuum pressure and detector dose rate were also examined. This paper describes the typical abort causes, optimizations of abort levels, and abort statistics over approximately eight years after having arrived at high beam current operation.

TUPB64

Methods to Reduce the System Error for High Power MSSW Emittance Meter

emittance, ion, ion-source, electron

496

S.X. Peng, J. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Y. Xu, Z.X. Yuan, J. Zhao
PKU, Beijing, People's Republic of China

Recently a new Multi-Slit Single-Wire (MSSW) type high power beam emittance meter named as HIBEMU-5 has developed in Peking University (PKU). Compared to previous MSSW devices, HIBEMU-5 greatly reduced the system error from 16.4% to 3.7% by specific designs to solve the incomplete short-slit sampling and fixed slit-wire distance. The problems of previous PKU devices are analyzed in part one. In part two, we describe the specific updating methods to solve its short-slit disadvantage by re-designing a longer-slit board with sufficient cooling, detail the mechanical scheme of changing the slit-wire distance for different beam divergence. The commissioning results given at part three prove that this new long slits design is successful to complete the beam sampling without being distorted by high power H⁺ beam. And the movable wire cup is able to locate the best measurement position for different beam focusing.

WECD01

Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program

detector, positron, optics, electron

585

N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad
CLASSE, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan

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 CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x10⁹ to 1x10¹¹ particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources.

Slides WECD01 [3.480 MB]

THCB02

Twisting Wire Scanner

feedback, software, controls, monitoring

607

V. Gharibyan, A. Delfs, I. Krouptchenkov, D. Nölle, H. Tiessen, M. Werner, K. Wittenburg
DESY, Hamburg, Germany

A new type of 'two-in-one' wire scanner is proposed. Recent advances in linear motors' technology make it possible to combine translational and rotational movements. This will allow to scan the beam in two perpendicular directions using a single driving motor and a special fork attached to it. Vertical or horizontal mounting will help to escape problems associated with the 45 deg scanners. Test results of the translational part with linear motors will be presented.

Slides THCB02 [5.591 MB]