IBIC2012 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOCB04	Vertical Emittance Measurements using a Vertical Undulator	undulator, photon, electron, brilliance	20
	K.P. Wootton, R.P. Rassool, G. Taylor The University of Melbourne, Melbourne, Australia M.J. Boland, B.C.C. Cowie, R.T. Dowd, Y.E. Tan ASCo, Clayton, Victoria, Australia Y. Papaphilippou CERN, Geneva, Switzerland
	With vertical dimensions of several microns, direct measurement of beam size is approaching diffraction limits of visible light and hard x-ray emittance diagnostics. We report on the development of a new vertical electron beam size measurement and monitoring technique which utilizes a vertical undulator. An APPLE-II type undulator was phased to produce a horizontal magnetic field, deflecting the electron beam in the vertical plane. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. Vertical electron beam emittances of several picometres have been observed at the Australian Synchrotron storage ring. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic.
	Slides MOCB04 [3.449 MB]

MOCC04	Improvement of Screen Monitor with Suppression of Coherent-OTR Effect for SACLA	electron, target, operation, radiation	34
	S. Matsubara, Y. Otake RIKEN/SPring-8, Hyogo, Japan S.I. Inoue SES, Hyogo-pref., Japan H. Maesaka RIKEN Spring-8 Harima, Hyogo, Japan
	The construction of SACLA (SPring-8 Angstrom Compact free electron LAser) was already completed and it is under operation. A screen monitor (SCM) system has been developed and was installed in order to obtain a direct image of a transverse beam profile with a spatial resolution of about 10 um, which is required to investigate electron-beam properties, such as a beam emittance. The SCM originally has a stainless steel target as a OTR radiator or a Ce:YAG crystal as a scintillation target. At the beginning of the SACLA operation, strong coherent OTR (COTR), which made an incorrect beam profile, was observed after bunch compressors. In order to suppress the COTR on the SCM, the stainless steel target was replaced to the Ce:YAG scintillation target. Since the COTR was still generated from the Ce:YAG target, a spatial mask was employed. The mask was mounted on the center of the optical line of the SCM, because the COTR light is emitted forward within ~1/γ radian, while the scintillation light has not angular dependence. Clear beam profiles with a diameter of a few tens of micro-meter are observed by means of the SCMs with this simple improvement.
	Slides MOCC04 [1.618 MB]

MOIC02	Electron Beam Diagnostic System for the Japanese XFEL, SACLA	undulator, electron, cavity, radiation	38
	H. Maesaka, H. Ego, C. Kondo, T. Ohshima, Y. Otake, H. Tomizawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Matsubara, T. Matsumoto, K. Yanagida JASRI/SPring-8, Hyogo, Japan
	An x-ray free-electron laser (XFEL) based on self-amplified spontaneous emission (SASE) requires a highly brilliant electron beam. The Japanese XFEL facility, SACLA, requires a normalized emittance less than 1 mm mrad and a peak current more than 3 kA. To achieve this high peak current, 1 A beam with 1 ns duration from a thermionic electron gun is compressed down to 30 fs by means of a multi-stage bunch compressor system. Therefore, the beam diagnostic system for SACLA was designed for the measurements of the emittance and bunch length at each compression stage. We developed a high-resolution transverse profile monitor and a temporal bunch structure measurement system with a C-band rf deflector cavity etc. In addition, precise overlapping between an electron beam and radiated x-rays in the undulator section is necessary to ensure the XFEL interaction. Therefore, we employed a C-band sub-micron resolution RF-BPM to fulfill the demanded accuracy of 4 um. The beam diagnostic system surely contributed to the first x-ray lasing at a wavelength of 1.2 Angstrom. We present a design strategy of the whole beam diagnostic system and the achieved performance for each monitor.
	Slides MOIC02 [7.861 MB]

MOPB52	Status and Activities of the SPring-8 Diagnostics Beamlines	photon, diagnostics, optics, storage-ring	186
	S. Takano, M. Masaki, A. Mochihashi, H. Ohkuma, M. Shoji, K. Tamura JASRI/SPring-8, Hyogo-ken, Japan H. Sumitomo, M. Yoshioka SES, Hyogo-pref., Japan
	At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress.

MOPB60	Beam Diagnostics for AREAL RF Photogun Linac	diagnostics, linac, gun, electron	212
	K. Manukyan, G.A. Amatuni, B. Grigoryan, V. Sahakyan, A. Sargsyan, G.S. Zanyan CANDLE, Yerevan, Armenia
	Advanced Research Electron Accelerator Laboratory (AREAL) based on photocathode RF gun is under construction at CANDLE. The basic approach to the new facility is the photocathode S-band RF electron gun followed by two 1 m long S-band travelling wave accelerating sections. Linac will operate in single bunch mode with final beam energy up to 20 MeV and the bunch charge 10 - 200 pC. In this paper the main approaches and characteristics of transverse and longitudinal beam diagnostics are presented.

MOPB63	Emittance Measurement using X-ray Beam Profile Monitor at KEK-ATF	controls, software, damping, electron	215
	T. Naito, H. Hayano, K. Kubo, S. Kuroda, N. Nakamura, T. Okugi, H. Sakai, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	The X-ray profile monitor (XPM) is used for the beam size measurement in the KEK-ATF damping ring(ATF-DR) at all times. The XPM consists of a crystal monochromator, two Fresnel zone plates(FZPs) and X-ray CCD camera. Two FZPs make the imaging optics. The design resolution of the selected wavelength 3.8nm is less than 1μm, which is sufficiently small for the emittance measurement of the ATF-DR. However, the measured results at the early stage were affected by the mechanical vibration. This paper describes the improvement of the resolution and the measurement results.

MOPB70	The Synchrotron Radiation Diagnostic Line at SSRF	synchrotron, radiation, synchrotron-radiation, feedback	232
	J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, K.R. Ye, W.M. Zhou SINAP, Shanghai, People's Republic of China
	The synchrotron radiation photon beam line has been operated since 2009 at Shanghai Synchrotron Radiation Facility. There are two diagnostic beam lines of the storage ring behind bending magnet, which is employed conventional X-ray and visible imaging techniques. A synchrotron radiation (SR) interferometer using visible light region in order to measure the small transverse electron beam size (about 22μm); low emittance and a low coupling. A small off-axis mirror is set for the convenience of the observation. Wave front testing is used for interferometer to calibrate the deformation effect of optical components. An X-ray pin-hole camera is also employed in the diagnostics beamline of the ring to characterize beam. Typically the point spread function of the X-ray pinhole camera is calculated via analytical or numerical method. Those two methods check each other. As a result, the measurement with SR system has quite enough resolution of itself even though the absolute beam size acquired. The existed system suffers with dynamic problem for beam physics studies. It has been measured 2.8nm.rad in small emittance mode at SSRF.

MOPB80	High Dynamic Range Beam Imaging with Two Simultaneously Sampling CCDs	FEL, linac, operation, brightness	263
	P.E. Evtushenko, D. Douglas JLAB, Newport News, Virginia, USA
	Transverse beam profile measurement with sufficiently high dynamic range (HDR) is a key diagnostic to measure the beam halo, understand its sources and evolution. In this contribution we describe our initial experience with the HDR imaging of the electron beam at the JLab FEL. On contrary to HDR measurements made with wire scanners in counting mode, which provide only two or three 1D projections of transverse beam distribution, imaging allows to measure the distribution itself. That is especially important for non-equilibrium beams in the LINACs. The measurements were made by means of simultaneous imaging with two CCD sensors with different exposure time. Two images are combined then numerically in to one HDR image. The system works as an online tool providing HDR images at 4 Hz. An optically polished YAG:Ce crystal with the thickness of 100 um was used for the measurements. When tested with a laser beam images with the DR of about 10⁺⁵ were obtained. With the electron beam the DR was somewhat smaller due to the limitations in the time structure of the tune-up beam macro pulse.

TUCC01	Electron Storage Ring as a Single Shot Linac Beam Monitor	injection, linac, synchrotron, electron	302
	Y. Shoji, K. Takeda LASTI, Hyogo, Japan T. Asaka, Y. Minagawa, S. Suzuki, Y. Takemura JASRI/SPring-8, Hyogo-ken, Japan
	The SPring-8 linac has been operated as an injector to the electron storage ring, NewSUBARU. Because of the small acceptance of the ring, fine parameter tuning is required for the stable top-up injection. In that process, some single shot linac beam measurements were necessary to understand the shot-by-shot fluctuation of the injection efficiency. We used the electron ring itself as a linac beam monitor. The time-resolving visible light monitor in the ring records the profiles of the injected linac beam for many revolutions. The pulse width for the single rf bucket (500MHz) of the ring is normally 1 ns, which contains 3 linac bunches (2856MHz). The time profile in the ring gives the energy profile at after 1/4 of the synchrotron oscillation period. The spatial profile of several revolutions, recorded by a double-sweep streak camera or ICCD gated camera, gives a beam emittance of a single-shot. The streak camera enables the bunch by bunch measurement. The effective resolution depends on the beta function of the ring, which can easily be changed. For the vertical emittance, our spatial resolution of 0.3 mm FWHM at βy = 17 m was good enough to identify the quadrupole mismatch.
	Slides TUCC01 [1.481 MB]

TUCC03	Design and Expected Performance of the New SLS Beam Size Monitor	polarization, synchrotron, storage-ring, synchrotron-radiation	307
	N. Milas, M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun PSI, Villigen PSI, Switzerland Å. Andersson, J. Breunlin MAX-lab, Lund, Sweden
	The vertical emittance minimization campaign at SLS, realized in the context of the TIARA WP6, has already achieved the world's smallest vertical emittance of 0.9 pm in a synchrotron light source. The minimum value reached for the vertical emittance is only five times bigger than the quantum limit of 0.2 pm. However, the resolution limit of the present SLS emittance monitor has also been reached thus, to further continue the emittance minimization program the construction of an improved second monitor is necessary. In this paper we present the design and studies on the performance of this new monitor based on the image formation method using vertically polarized synchrotron radiation in the vis-UV spectral regimes. This monitor includes a new feature, providing the possibility of performing full interferometric measurement by the use of a set of vertical obstacles that can be driven on the light path. Simulations results are used to investigate the possible source of errors and their effects on imaging and the determination of the beam height. We also present the expected performance, in term of emittance accuracy and precision, and discuss possible design limitations.
	Slides TUCC03 [8.497 MB]

TUPB51	Gatling Gun Test Stand Instrumentation	electron, gun, cathode, diagnostics	474
	D.M. Gassner, I. Ben-Zvi, J.C. Brutus, C. Liu, M.G. Minty, A.I. Pikin, O.H. Rahman, E.J. Riehn, J. Skaritka, E. Wang BNL, Upton, Long Island, New York, USA
	In order to reach the design eRHIC luminosity 50mA of polarized electron current is needed. This is far beyond what the present state-of-the-art polarized electron cathode can deliver. A high average polarized current injector based on the Gatling Gun principle is being designed. This technique will employ multiple cathodes and combine their multiple bunched beams along the same axis. A proof-of-principle test bench will be constructed that includes a 220 keV Gatling Gun, beam combiner, diagnostics station, and collector. The challenges for the instrumentation systems and the beam diagnostics that will measure current, profile, position, and halo will be described.

TUPB61	The First Experience with the LHC Beam Gas Ionisation Monitor	electron, injection, controls, proton	489
	M. Sapinski, W. Andreazza, B. Dehning, A. Guerrero, M. Patecki, R. Versteegen CERN, Geneva, Switzerland
	The Beam Gas Ionisation Monitors (BGI) are used to continuously measure the beam size at the LHC. This paper describes the detectors and their operation and discusses the issues encountered during the commissioning. It also discusses the various calibration procedures used to correct for non-uniformity of Multi-Channel plates and to correct the beam size for effects affecting the electron trajectory after ionisation.

TUPB64	Methods to Reduce the System Error for High Power MSSW Emittance Meter	ion, vacuum, 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.

TUPB65	Transverse-acceptance Measurement System for the JAEA AVF Cyclotron	injection, cyclotron, ion, ion-source	499
	H. Kashiwagi, S. Kurashima, N. Miyawaki, S. Okumura JAEA/TARRI, Gunma-ken, Japan
	We are developing an acceptance measurement system to evaluate transverse phase-space matching of the emittance of an injection beam to the acceptance of the AVF cyclotron. The system is composed of a phase-space collimator in the low energy section and a beam intensity monitor in the high energy section. The phase-space collimator, which consists of two pairs of slits, allows very small-emittance beams to be injected into the cyclotron by limiting position and divergence angle of the beam from an ion source. The beam intensity monitor is used to obtain the ratio of beam intensity at the collimator to that at the monitor. In acceptance measurement, the small-emittance beams at various positions in a transverse phase-plane are injected to determine the distribution of relative transmission in the phase plane. In preliminary tests, only a part of acceptance was able to be measured because the injection-beam emittance from ion sources does not cover the whole acceptance. To expand the measurement area, a steering magnet has been added in the system. The magnet scans the injection beam in phase planes in synchronization with the acceptance measurement to simulate the large emittance.

TUPB70	The ATF2 Multi-OTR System: Studies and Design Improvements	target, coupling, operation, wakefield	505
	J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López IFIC, Valencia, Spain J. Cruz, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Funding Agency: FPA2010-21456-C02-01 Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-Optical Transition Radiation system made of four stations has been installed in the extraction line of ATF2 and has been fully operational since September 2011. The system is being used routinely for beam size and emittance measurements as well as for coupling correction and energy spread measurements. In this paper we present the beam sizes and emittance measurements performed during 2012 runs as well as a detailed study of the experimental single-shot automated coupling correction and the comparison with the simulations. Wakefields problems experimented with the simultaneous measurement has been studied and will be solved by new target holders that will be installed in the next Fall 2012 run.

TUPB78	Flying Wire Beam Profile Monitors at the J-PARC MR	injection, timing, proton, background	527
	S. Igarashi, D.A. Arakawa, Y. Hashimoto, M. Tejima, T. Toyama KEK, Ibaraki, Japan K. Hanamura Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	Transverse beam profiles have been measured using flying wire monitors at the main ring of the Japan Proton Accelerator Research Complex. The wire target should be thin and the wire scan has to be fast for the precise profile measurement. Otherwise the beam distribution would be disturbed and the measured profile would not be accurate. We use carbon fibers of 7 μm in diameter and the scan speed of 10 m/s. The wire is attached with an aluminum flame of 140 mm of the rotation radius and rotated with a DC servomotor. A potentiometer is attached to the wire flame and the angle readout is used for the feedback of the servomotor and the wire position measurement. The secondary particles from the beam-wire scattering are measured with a scintillation counter. Beam profiles are reconstructed by making the scatter plot of the scintillator signal and wire position. Both horizontal and vertical flying wire monitors have been used for the beam commissioning. We have successfully measured the beam profile of up to 1.2×10¹³ protons per bunch.

Paper

Title

Other Keywords

Page

MOCB04

Vertical Emittance Measurements using a Vertical Undulator

undulator, photon, electron, brilliance

20

K.P. Wootton, R.P. Rassool, G. Taylor
The University of Melbourne, Melbourne, Australia
M.J. Boland, B.C.C. Cowie, R.T. Dowd, Y.E. Tan
ASCo, Clayton, Victoria, Australia
Y. Papaphilippou
CERN, Geneva, Switzerland

With vertical dimensions of several microns, direct measurement of beam size is approaching diffraction limits of visible light and hard x-ray emittance diagnostics. We report on the development of a new vertical electron beam size measurement and monitoring technique which utilizes a vertical undulator. An APPLE-II type undulator was phased to produce a horizontal magnetic field, deflecting the electron beam in the vertical plane. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. Vertical electron beam emittances of several picometres have been observed at the Australian Synchrotron storage ring. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic.

Slides MOCB04 [3.449 MB]

MOCC04

Improvement of Screen Monitor with Suppression of Coherent-OTR Effect for SACLA

electron, target, operation, radiation

34

S. Matsubara, Y. Otake
RIKEN/SPring-8, Hyogo, Japan
S.I. Inoue
SES, Hyogo-pref., Japan
H. Maesaka
RIKEN Spring-8 Harima, Hyogo, Japan

The construction of SACLA (SPring-8 Angstrom Compact free electron LAser) was already completed and it is under operation. A screen monitor (SCM) system has been developed and was installed in order to obtain a direct image of a transverse beam profile with a spatial resolution of about 10 um, which is required to investigate electron-beam properties, such as a beam emittance. The SCM originally has a stainless steel target as a OTR radiator or a Ce:YAG crystal as a scintillation target. At the beginning of the SACLA operation, strong coherent OTR (COTR), which made an incorrect beam profile, was observed after bunch compressors. In order to suppress the COTR on the SCM, the stainless steel target was replaced to the Ce:YAG scintillation target. Since the COTR was still generated from the Ce:YAG target, a spatial mask was employed. The mask was mounted on the center of the optical line of the SCM, because the COTR light is emitted forward within ~1/γ radian, while the scintillation light has not angular dependence. Clear beam profiles with a diameter of a few tens of micro-meter are observed by means of the SCMs with this simple improvement.

Slides MOCC04 [1.618 MB]

MOIC02

Electron Beam Diagnostic System for the Japanese XFEL, SACLA

undulator, electron, cavity, radiation

38

H. Maesaka, H. Ego, C. Kondo, T. Ohshima, Y. Otake, H. Tomizawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Matsubara, T. Matsumoto, K. Yanagida
JASRI/SPring-8, Hyogo, Japan

An x-ray free-electron laser (XFEL) based on self-amplified spontaneous emission (SASE) requires a highly brilliant electron beam. The Japanese XFEL facility, SACLA, requires a normalized emittance less than 1 mm mrad and a peak current more than 3 kA. To achieve this high peak current, 1 A beam with 1 ns duration from a thermionic electron gun is compressed down to 30 fs by means of a multi-stage bunch compressor system. Therefore, the beam diagnostic system for SACLA was designed for the measurements of the emittance and bunch length at each compression stage. We developed a high-resolution transverse profile monitor and a temporal bunch structure measurement system with a C-band rf deflector cavity etc. In addition, precise overlapping between an electron beam and radiated x-rays in the undulator section is necessary to ensure the XFEL interaction. Therefore, we employed a C-band sub-micron resolution RF-BPM to fulfill the demanded accuracy of 4 um. The beam diagnostic system surely contributed to the first x-ray lasing at a wavelength of 1.2 Angstrom. We present a design strategy of the whole beam diagnostic system and the achieved performance for each monitor.

Slides MOIC02 [7.861 MB]

MOPB52

Status and Activities of the SPring-8 Diagnostics Beamlines

photon, diagnostics, optics, storage-ring

186

S. Takano, M. Masaki, A. Mochihashi, H. Ohkuma, M. Shoji, K. Tamura
JASRI/SPring-8, Hyogo-ken, Japan
H. Sumitomo, M. Yoshioka
SES, Hyogo-pref., Japan

At SPring-8 synchrotron radiation (SR) in both the X-ray and the visible bands is exploited in the two diagnostics beamlines. The diagnostics I beamline has a dipole magnet source. The beam size is measured by imaging with the zoneplate X-ray optics. Recently, the transfer line of the visible light has been upgraded. The in-vacuum mirror was replaced to increase the acceptance of the visible photons. A new dark room was built and dedicated to the gated photon counting system for bunch purity monitoring. To improve the performance, the input optics of the visible streak camera was replaced by a reflective optics. Study of the power fluctuation of visible SR pulse is in progress to develop a diagnostic method of short bunch length. The diagnostics II has an insertion device (ID). To monitor stabilities of the ID photon beam, a position monitor for the white X-ray beam based on a CVD diamond screen was installed. A turn-by-turn diagnostics system using the monochromatic X-ray beam was developed to observe fast phenomena such as beam oscillation at injection for top-up and beam blowups caused by instabilities. Study of temporal resolution of the X-ray streak camera is also in progress.

MOPB60

Beam Diagnostics for AREAL RF Photogun Linac

diagnostics, linac, gun, electron

212

K. Manukyan, G.A. Amatuni, B. Grigoryan, V. Sahakyan, A. Sargsyan, G.S. Zanyan
CANDLE, Yerevan, Armenia

Advanced Research Electron Accelerator Laboratory (AREAL) based on photocathode RF gun is under construction at CANDLE. The basic approach to the new facility is the photocathode S-band RF electron gun followed by two 1 m long S-band travelling wave accelerating sections. Linac will operate in single bunch mode with final beam energy up to 20 MeV and the bunch charge 10 - 200 pC. In this paper the main approaches and characteristics of transverse and longitudinal beam diagnostics are presented.

MOPB63

Emittance Measurement using X-ray Beam Profile Monitor at KEK-ATF

controls, software, damping, electron

215

T. Naito, H. Hayano, K. Kubo, S. Kuroda, N. Nakamura, T. Okugi, H. Sakai, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

The X-ray profile monitor (XPM) is used for the beam size measurement in the KEK-ATF damping ring(ATF-DR) at all times. The XPM consists of a crystal monochromator, two Fresnel zone plates(FZPs) and X-ray CCD camera. Two FZPs make the imaging optics. The design resolution of the selected wavelength 3.8nm is less than 1μm, which is sufficiently small for the emittance measurement of the ATF-DR. However, the measured results at the early stage were affected by the mechanical vibration. This paper describes the improvement of the resolution and the measurement results.

MOPB70

The Synchrotron Radiation Diagnostic Line at SSRF

synchrotron, radiation, synchrotron-radiation, feedback

232

J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, K.R. Ye, W.M. Zhou
SINAP, Shanghai, People's Republic of China

The synchrotron radiation photon beam line has been operated since 2009 at Shanghai Synchrotron Radiation Facility. There are two diagnostic beam lines of the storage ring behind bending magnet, which is employed conventional X-ray and visible imaging techniques. A synchrotron radiation (SR) interferometer using visible light region in order to measure the small transverse electron beam size (about 22μm); low emittance and a low coupling. A small off-axis mirror is set for the convenience of the observation. Wave front testing is used for interferometer to calibrate the deformation effect of optical components. An X-ray pin-hole camera is also employed in the diagnostics beamline of the ring to characterize beam. Typically the point spread function of the X-ray pinhole camera is calculated via analytical or numerical method. Those two methods check each other. As a result, the measurement with SR system has quite enough resolution of itself even though the absolute beam size acquired. The existed system suffers with dynamic problem for beam physics studies. It has been measured 2.8nm.rad in small emittance mode at SSRF.

MOPB80

High Dynamic Range Beam Imaging with Two Simultaneously Sampling CCDs

FEL, linac, operation, brightness

263

P.E. Evtushenko, D. Douglas
JLAB, Newport News, Virginia, USA

Transverse beam profile measurement with sufficiently high dynamic range (HDR) is a key diagnostic to measure the beam halo, understand its sources and evolution. In this contribution we describe our initial experience with the HDR imaging of the electron beam at the JLab FEL. On contrary to HDR measurements made with wire scanners in counting mode, which provide only two or three 1D projections of transverse beam distribution, imaging allows to measure the distribution itself. That is especially important for non-equilibrium beams in the LINACs. The measurements were made by means of simultaneous imaging with two CCD sensors with different exposure time. Two images are combined then numerically in to one HDR image. The system works as an online tool providing HDR images at 4 Hz. An optically polished YAG:Ce crystal with the thickness of 100 um was used for the measurements. When tested with a laser beam images with the DR of about 10⁺⁵ were obtained. With the electron beam the DR was somewhat smaller due to the limitations in the time structure of the tune-up beam macro pulse.

TUCC01

Electron Storage Ring as a Single Shot Linac Beam Monitor

injection, linac, synchrotron, electron

302

Y. Shoji, K. Takeda
LASTI, Hyogo, Japan
T. Asaka, Y. Minagawa, S. Suzuki, Y. Takemura
JASRI/SPring-8, Hyogo-ken, Japan

The SPring-8 linac has been operated as an injector to the electron storage ring, NewSUBARU. Because of the small acceptance of the ring, fine parameter tuning is required for the stable top-up injection. In that process, some single shot linac beam measurements were necessary to understand the shot-by-shot fluctuation of the injection efficiency. We used the electron ring itself as a linac beam monitor. The time-resolving visible light monitor in the ring records the profiles of the injected linac beam for many revolutions. The pulse width for the single rf bucket (500MHz) of the ring is normally 1 ns, which contains 3 linac bunches (2856MHz). The time profile in the ring gives the energy profile at after 1/4 of the synchrotron oscillation period. The spatial profile of several revolutions, recorded by a double-sweep streak camera or ICCD gated camera, gives a beam emittance of a single-shot. The streak camera enables the bunch by bunch measurement. The effective resolution depends on the beta function of the ring, which can easily be changed. For the vertical emittance, our spatial resolution of 0.3 mm FWHM at βy = 17 m was good enough to identify the quadrupole mismatch.

Slides TUCC01 [1.481 MB]

TUCC03

Design and Expected Performance of the New SLS Beam Size Monitor

polarization, synchrotron, storage-ring, synchrotron-radiation

307

N. Milas, M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun
PSI, Villigen PSI, Switzerland
Å. Andersson, J. Breunlin
MAX-lab, Lund, Sweden

The vertical emittance minimization campaign at SLS, realized in the context of the TIARA WP6, has already achieved the world's smallest vertical emittance of 0.9 pm in a synchrotron light source. The minimum value reached for the vertical emittance is only five times bigger than the quantum limit of 0.2 pm. However, the resolution limit of the present SLS emittance monitor has also been reached thus, to further continue the emittance minimization program the construction of an improved second monitor is necessary. In this paper we present the design and studies on the performance of this new monitor based on the image formation method using vertically polarized synchrotron radiation in the vis-UV spectral regimes. This monitor includes a new feature, providing the possibility of performing full interferometric measurement by the use of a set of vertical obstacles that can be driven on the light path. Simulations results are used to investigate the possible source of errors and their effects on imaging and the determination of the beam height. We also present the expected performance, in term of emittance accuracy and precision, and discuss possible design limitations.

Slides TUCC03 [8.497 MB]

TUPB51

Gatling Gun Test Stand Instrumentation

electron, gun, cathode, diagnostics

474

D.M. Gassner, I. Ben-Zvi, J.C. Brutus, C. Liu, M.G. Minty, A.I. Pikin, O.H. Rahman, E.J. Riehn, J. Skaritka, E. Wang
BNL, Upton, Long Island, New York, USA

In order to reach the design eRHIC luminosity 50mA of polarized electron current is needed. This is far beyond what the present state-of-the-art polarized electron cathode can deliver. A high average polarized current injector based on the Gatling Gun principle is being designed. This technique will employ multiple cathodes and combine their multiple bunched beams along the same axis. A proof-of-principle test bench will be constructed that includes a 220 keV Gatling Gun, beam combiner, diagnostics station, and collector. The challenges for the instrumentation systems and the beam diagnostics that will measure current, profile, position, and halo will be described.

TUPB61

The First Experience with the LHC Beam Gas Ionisation Monitor

electron, injection, controls, proton

489

M. Sapinski, W. Andreazza, B. Dehning, A. Guerrero, M. Patecki, R. Versteegen
CERN, Geneva, Switzerland

The Beam Gas Ionisation Monitors (BGI) are used to continuously measure the beam size at the LHC. This paper describes the detectors and their operation and discusses the issues encountered during the commissioning. It also discusses the various calibration procedures used to correct for non-uniformity of Multi-Channel plates and to correct the beam size for effects affecting the electron trajectory after ionisation.

TUPB64

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

ion, vacuum, 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.

TUPB65

Transverse-acceptance Measurement System for the JAEA AVF Cyclotron

injection, cyclotron, ion, ion-source

499

H. Kashiwagi, S. Kurashima, N. Miyawaki, S. Okumura
JAEA/TARRI, Gunma-ken, Japan

We are developing an acceptance measurement system to evaluate transverse phase-space matching of the emittance of an injection beam to the acceptance of the AVF cyclotron. The system is composed of a phase-space collimator in the low energy section and a beam intensity monitor in the high energy section. The phase-space collimator, which consists of two pairs of slits, allows very small-emittance beams to be injected into the cyclotron by limiting position and divergence angle of the beam from an ion source. The beam intensity monitor is used to obtain the ratio of beam intensity at the collimator to that at the monitor. In acceptance measurement, the small-emittance beams at various positions in a transverse phase-plane are injected to determine the distribution of relative transmission in the phase plane. In preliminary tests, only a part of acceptance was able to be measured because the injection-beam emittance from ion sources does not cover the whole acceptance. To expand the measurement area, a steering magnet has been added in the system. The magnet scans the injection beam in phase planes in synchronization with the acceptance measurement to simulate the large emittance.

TUPB70

The ATF2 Multi-OTR System: Studies and Design Improvements

target, coupling, operation, wakefield

505

J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Funding Agency: FPA2010-21456-C02-01 Work supported in part by Department of Energy Contract DE-AC02-76SF00515.
A multi-Optical Transition Radiation system made of four stations has been installed in the extraction line of ATF2 and has been fully operational since September 2011. The system is being used routinely for beam size and emittance measurements as well as for coupling correction and energy spread measurements. In this paper we present the beam sizes and emittance measurements performed during 2012 runs as well as a detailed study of the experimental single-shot automated coupling correction and the comparison with the simulations. Wakefields problems experimented with the simultaneous measurement has been studied and will be solved by new target holders that will be installed in the next Fall 2012 run.

TUPB78

Flying Wire Beam Profile Monitors at the J-PARC MR

injection, timing, proton, background

527

S. Igarashi, D.A. Arakawa, Y. Hashimoto, M. Tejima, T. Toyama
KEK, Ibaraki, Japan
K. Hanamura
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

Transverse beam profiles have been measured using flying wire monitors at the main ring of the Japan Proton Accelerator Research Complex. The wire target should be thin and the wire scan has to be fast for the precise profile measurement. Otherwise the beam distribution would be disturbed and the measured profile would not be accurate. We use carbon fibers of 7 μm in diameter and the scan speed of 10 m/s. The wire is attached with an aluminum flame of 140 mm of the rotation radius and rotated with a DC servomotor. A potentiometer is attached to the wire flame and the angle readout is used for the feedback of the servomotor and the wire position measurement. The secondary particles from the beam-wire scattering are measured with a scintillation counter. Beam profiles are reconstructed by making the scatter plot of the scintillator signal and wire position. Both horizontal and vertical flying wire monitors have been used for the beam commissioning. We have successfully measured the beam profile of up to 1.2×10¹³ protons per bunch.