IBIC2012 - List of Authors (Mitsuhashi, T.M.)

Paper

Title

Page

Development of Offner Relay Optical System for OTR Monitor at 3-50 Beam Transport Line of J-PARC

222

M. Tejima, T.M. Mitsuhashi
KEK, Ibaraki, Japan
Y. Hashimoto, T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
S. Otsu
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

An extremely wide aperture relay optical system based on Offner system has been designed and constracted for OTR monitor at 3-50 beam transport line of J-PARC. Diagnostics for beam profile and halo are very important to optimize injection beam from RCS to MR in J-PARC. For this purpose, an OTR monitor is planed to install for an observation of image of the beam and halo after the beam collimators. Since opening of OTR is very wide due to small Gamma; 3.2, extremely wide aperture (500mrad) optics will necessary to extract OTR from file target. We designed Offner type relay optics for the effective extraction of OTR having F=0.83. The clear aperture will cover 100 x 100mm aria on the target screen. Results of optical testing and design of OTR monitor will present in this paper.

MOPB72

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

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.

MOPB83

Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring

276

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process.

TUPB72

Injected Beam Profile Measurement during Top-up Operation

508

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

A coronagraph-like apparatus was constructed on the optical diagnostic beamline on the storage ring to observe the injected beam during top-up operations. An image was created on an intensified CCD that can be gated on a single bunch or on a bunch train for a stronger signal. The bright central stored beam was obscured so the comparatively faint injected beam could be observed. The injected beam comes in at a large enough offset so that it was clearly visible above any diffraction or beam halo signals. The beam profile measured was in good agreement with the observations made of the injected beam only using a telescope apparatus. The measurements were made during user beam in top-up operation mode and can be used to optimise the injection process.

WECC03

Intensity Imbalance Optical Interferometer Beam Size Monitor

566

M.J. Boland
ASCo, Clayton, Victoria, Australia
T.M. Mitsuhashi, T. Naito
KEK, Ibaraki, Japan
K.P. Wootton
The University of Melbourne, Melbourne, Australia

The technique of measuring the beam size in a particle accelerator with an optical interferometer with the Mitsuhashi apparatus is well established and one of the only direct measurement techniques available. However, one of the limitations of the technique is the dynamic range and noise level of CCD cameras when measuring ultra low emittance beams and hence visibilities close to unity. A new design has been successfully tested to overcome these limitations by introducing a know intensity imbalance in one of the light paths of the interferometer. This modification reduces the visibility in a controlled way and lifts the measured interference pattern out of the noise level of the CCD, thus increasing the dynamic range of the apparatus. Results are presented from tests at the ATF2 at KEK and on the optical diagnostic beamline at the Australian Synchrotron storage ring.

Slides WECC03 [2.383 MB]

WEIC02

Recent Progress in SR Interferometer

576

T.M. Mitsuhashi
KEK, Ibaraki, Japan

Beam size measurement in accelerator is very important to evaluate beam emittance.　SR interferometer has been used as one of powerful tools for measurement of small beam size through special coherence of visible SR. Recent progresses in this technique improve measurable range for smaller beam size less than 10μm. An application of reflective optics to eliminate chromatic aberration in focus system of SR interferometer makes it possible to measure the beam size down to 5μm range. The unbalanced input technique is developed in recent few years, and this technique magnifies beam size 2-3 times, and observation range is improved down to 2-3μm range. These progresses on SR interferometer will introduce in this talk.

Slides WEIC02 [1.687 MB]

Paper	Title	Page
MOPB67	Development of Offner Relay Optical System for OTR Monitor at 3-50 Beam Transport Line of J-PARC	222
	M. Tejima, T.M. Mitsuhashi KEK, Ibaraki, Japan Y. Hashimoto, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan S. Otsu Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	An extremely wide aperture relay optical system based on Offner system has been designed and constracted for OTR monitor at 3-50 beam transport line of J-PARC. Diagnostics for beam profile and halo are very important to optimize injection beam from RCS to MR in J-PARC. For this purpose, an OTR monitor is planed to install for an observation of image of the beam and halo after the beam collimators. Since opening of OTR is very wide due to small Gamma; 3.2, extremely wide aperture (500mrad) optics will necessary to extract OTR from file target. We designed Offner type relay optics for the effective extraction of OTR having F=0.83. The clear aperture will cover 100 x 100mm aria on the target screen. Results of optical testing and design of OTR monitor will present in this paper.

MOPB72	First Measurements with Coded Aperture X-ray Monitor at the ATF2 Extraction Line	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.

MOPB83	Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring	276
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process.

TUPB72	Injected Beam Profile Measurement during Top-up Operation	508
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	A coronagraph-like apparatus was constructed on the optical diagnostic beamline on the storage ring to observe the injected beam during top-up operations. An image was created on an intensified CCD that can be gated on a single bunch or on a bunch train for a stronger signal. The bright central stored beam was obscured so the comparatively faint injected beam could be observed. The injected beam comes in at a large enough offset so that it was clearly visible above any diffraction or beam halo signals. The beam profile measured was in good agreement with the observations made of the injected beam only using a telescope apparatus. The measurements were made during user beam in top-up operation mode and can be used to optimise the injection process.

WECC03	Intensity Imbalance Optical Interferometer Beam Size Monitor	566
	M.J. Boland ASCo, Clayton, Victoria, Australia T.M. Mitsuhashi, T. Naito KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	The technique of measuring the beam size in a particle accelerator with an optical interferometer with the Mitsuhashi apparatus is well established and one of the only direct measurement techniques available. However, one of the limitations of the technique is the dynamic range and noise level of CCD cameras when measuring ultra low emittance beams and hence visibilities close to unity. A new design has been successfully tested to overcome these limitations by introducing a know intensity imbalance in one of the light paths of the interferometer. This modification reduces the visibility in a controlled way and lifts the measured interference pattern out of the noise level of the CCD, thus increasing the dynamic range of the apparatus. Results are presented from tests at the ATF2 at KEK and on the optical diagnostic beamline at the Australian Synchrotron storage ring.
	Slides WECC03 [2.383 MB]

WEIC02	Recent Progress in SR Interferometer	576
	T.M. Mitsuhashi KEK, Ibaraki, Japan
	Beam size measurement in accelerator is very important to evaluate beam emittance.　SR interferometer has been used as one of powerful tools for measurement of small beam size through special coherence of visible SR. Recent progresses in this technique improve measurable range for smaller beam size less than 10μm. An application of reflective optics to eliminate chromatic aberration in focus system of SR interferometer makes it possible to measure the beam size down to 5μm range. The unbalanced input technique is developed in recent few years, and this technique magnifies beam size 2-3 times, and observation range is improved down to 2-3μm range. These progresses on SR interferometer will introduce in this talk.
	Slides WEIC02 [1.687 MB]