IBIC2013 - List of Authors (Mitsuhashi, T.M.)

Paper

Title

Page

Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics

97

R.J. Steinhagen
CERN, Geneva, Switzerland
M.J. Boland
SLSA, Clayton, Australia
T.G. Lucas, R.P. Rassool
The University of Melbourne, Melbourne, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan

The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators the use of optical diagnostic techniques for this purpose is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependable means to measure signals deriving from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN's CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The used amplification schemes, achieved sensitivities, linearity, and dynamic range of the detector setup are presented.

Poster MOPC20 [3.065 MB]

MOPF01

Transverse Beam Size Measurements Using Interferometry at ALBA

193

U. Iriso, L. Torino
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
T.M. Mitsuhashi
KEK, Ibaraki, Japan

Double-slit interferometry using visible light has been used for measuring the transverse beam size in different accelerators. The beam size is inferred from the analysis of the spatial coherence of the synchrotron light produced by a bending magnet. At ALBA, this technique has been implemented with moderate success, mainly limited by the present imperfections in the in-vacuum mirror that is used to extract the light out of the vacuum chamber. In this paper, we report the results obtained with the current set-up, and discuss possible improvements.

TUCL2

A Development of High Sensitive Beam Profile Monitor using Multi-Screen

338

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

The diagnostics of beam halo as well as beam core are very important for the regulation of the beam collimator. We have developed a monitor to observe two-dimensional beam profile with a large dynamic range. The monitor has been installed in 122m downstream from the beam collimator in 3-50 BT in the J-PARC. For measuring the beam core and the halo alternatively, the monitor has three kinds of screens. The first one is titanium foil OTR screen to measure a beam core, the second one is aluminum foil OTR screen having a hole (50 mm diameter) in the center, and the last one is a pair of alumina fluorescent screen with a separation of 80 mm in horizontal to observe the beam halo in surroundings. We designed an optical system based on the Offner optics for the observation of fluorescence and OTR lights. This optical system has an entrance aperture of 300 mm and it can cover the large opening angle (± 13.5 degree) of the OTR from 3GeV protons. A CID camera with an image intensifier (II) was use to observe the profile. We have succeeded to observe a profile of beam halo to 10^-6 order to the peak of beam core by using proton beams of 9.6 x 10¹² protons/pulse by this multi-screen scheme.

Slides TUCL2 [3.091 MB]

TUPF20

Low Noise and High Dynamic Range Optical Interferometer Beamsize Measurements

550

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

The technique of optical interferometry to measure beam sizes requires a low noise and high dynamic range digitisation system to push the performance to ultra low emittance on storage rings. The next generation of camera sensor Scientific CMOS (sCMOS) promises to provide the technology to improve optical interferometry. A series of measurements was performed on the Australian Synchrotron storage ring using a sCMOS and a intensity imbalance optical interferometer. The coupling in the storage ring was varied from maximum to minimum using the skew quadrupoles and the beam size at the optical diagnostic beamline was varied from over 100 microns to around 1 micron. A comparison is made between interferometer measurements using the sCMOS with and without an intensity imbalance and with previous measurements using a CCD system.

WEPC34

Time Trend Observation of Certain Remarked Bunches using a Streak Camera

761

T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T.M. Mitsuhashi, T. Okugi, S. Sakanaka, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work is supported by Japan-U.S. cooperative program .
A streak camera with two dimensional sweep function can measure the trend of the longitudinal beam profile in the ring. In the case of the multi-bunch measurement, the different bunch profile sit on same timing, thus, we can not distinguish the behavior of each bunch. We have developed a trigger circuit to measure the bunch-by-bunch longitudinal beam profile, which uses non integer sweep frequency for the acceleration frequency. The bunch profile of each bunch sit on different position in this measurement. We observed the increment of the synchrotron oscillation amplitude from the first bunch to the 20th bunch in the KEK-ATF Damping Ring by using this system. This paper describes the hardware and the measurement results.

Paper	Title	Page
MOPC20	Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics	97
	R.J. Steinhagen CERN, Geneva, Switzerland M.J. Boland SLSA, Clayton, Australia T.G. Lucas, R.P. Rassool The University of Melbourne, Melbourne, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan
	The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators the use of optical diagnostic techniques for this purpose is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependable means to measure signals deriving from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN's CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The used amplification schemes, achieved sensitivities, linearity, and dynamic range of the detector setup are presented.
	Poster MOPC20 [3.065 MB]

MOPF01	Transverse Beam Size Measurements Using Interferometry at ALBA	193
	U. Iriso, L. Torino CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain T.M. Mitsuhashi KEK, Ibaraki, Japan
	Double-slit interferometry using visible light has been used for measuring the transverse beam size in different accelerators. The beam size is inferred from the analysis of the spatial coherence of the synchrotron light produced by a bending magnet. At ALBA, this technique has been implemented with moderate success, mainly limited by the present imperfections in the in-vacuum mirror that is used to extract the light out of the vacuum chamber. In this paper, we report the results obtained with the current set-up, and discuss possible improvements.

TUCL2	A Development of High Sensitive Beam Profile Monitor using Multi-Screen	338
	Y. Hashimoto, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan T.M. Mitsuhashi, M. Tejima KEK, Ibaraki, Japan S. Otsu Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	The diagnostics of beam halo as well as beam core are very important for the regulation of the beam collimator. We have developed a monitor to observe two-dimensional beam profile with a large dynamic range. The monitor has been installed in 122m downstream from the beam collimator in 3-50 BT in the J-PARC. For measuring the beam core and the halo alternatively, the monitor has three kinds of screens. The first one is titanium foil OTR screen to measure a beam core, the second one is aluminum foil OTR screen having a hole (50 mm diameter) in the center, and the last one is a pair of alumina fluorescent screen with a separation of 80 mm in horizontal to observe the beam halo in surroundings. We designed an optical system based on the Offner optics for the observation of fluorescence and OTR lights. This optical system has an entrance aperture of 300 mm and it can cover the large opening angle (± 13.5 degree) of the OTR from 3GeV protons. A CID camera with an image intensifier (II) was use to observe the profile. We have succeeded to observe a profile of beam halo to 10^-6 order to the peak of beam core by using proton beams of 9.6 x 10¹² protons/pulse by this multi-screen scheme.
	Slides TUCL2 [3.091 MB]

TUPF20	Low Noise and High Dynamic Range Optical Interferometer Beamsize Measurements	550
	M.J. Boland SLSA, Clayton, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan K.P. Wootton The University of Melbourne, Melbourne, Australia
	The technique of optical interferometry to measure beam sizes requires a low noise and high dynamic range digitisation system to push the performance to ultra low emittance on storage rings. The next generation of camera sensor Scientific CMOS (sCMOS) promises to provide the technology to improve optical interferometry. A series of measurements was performed on the Australian Synchrotron storage ring using a sCMOS and a intensity imbalance optical interferometer. The coupling in the storage ring was varied from maximum to minimum using the skew quadrupoles and the beam size at the optical diagnostic beamline was varied from over 100 microns to around 1 micron. A comparison is made between interferometer measurements using the sCMOS with and without an intensity imbalance and with previous measurements using a CCD system.

WEPC34	Time Trend Observation of Certain Remarked Bunches using a Streak Camera	761
	T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T.M. Mitsuhashi, T. Okugi, S. Sakanaka, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: This work is supported by Japan-U.S. cooperative program . A streak camera with two dimensional sweep function can measure the trend of the longitudinal beam profile in the ring. In the case of the multi-bunch measurement, the different bunch profile sit on same timing, thus, we can not distinguish the behavior of each bunch. We have developed a trigger circuit to measure the bunch-by-bunch longitudinal beam profile, which uses non integer sweep frequency for the acceleration frequency. The bunch profile of each bunch sit on different position in this measurement. We observed the increment of the synchrotron oscillation amplitude from the first bunch to the 20th bunch in the KEK-ATF Damping Ring by using this system. This paper describes the hardware and the measurement results.