IPAC2012 - List of Authors (Kinsho, M.)

Paper

Title

Page

Reduction of Outgassing from the Ferrite Cores in the Kicker Magnet of J-PARC RCS

487

N. Ogiwara, Y. Hikichi, J. Kamiya, M. Kinsho, M. Nishikawa, K. Suganuma, T. Yanagibashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Kicker magnets are used to kick out the accelerated beam to the beam transport lines in the RCS of the J-PARC. A high voltage is applied to kickers for a short period, so they must be installed in a vacuum to prevent discharge. Therefore, it is important to reduce the outgassing of water vapor from the ferrite cores. After bake-out at 200°C for 300 hours, the outgassing rate decreased to less than 1×10^-7 Pam/s. However, the small amount of water vapor and carbon monoxide were emitted from the ferrite cores at charging voltage of 80 kV. This time, we have decided to construct the reserve magnets with very low outgassing at high-voltage discharge. First of all, the thermal desorption behavior of the ferrite was investigated. Water vapor has two peaks: at ~ 100°C and 350°C. Carbon monoxide is rather largely emitted until 300°C. From these results, the ferrite cores were vacuum-fired at 450°C for 10 h. Then the good properties for the magnetic cores were confirmed. And now the assembling of the kicker magnet is undertaken. The performance of the kicker magnet made of the vacuum-fired ferrite will be shown in this meeting.

MOPPD073

Development of Transportation System for Low Energy Electron Group

532

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
M. Kinsho, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

There is a time that we want to measure the electron which occurred in the accelerator in the small situation of a noise. In that case, it is one method that we transport these electrons to the place distant form the accelerator where a noise is small. In order to realize that, development of transport line for low energy electrons is required. So, we start to develop transport line using solenoid magnets. We present status of development of this transportation system.

MOPPD074

Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection

535

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

WEOAA03

Development of the Beam Halo Monitor in the J-PARC 3-GeV RCS

2122

M. Yoshimoto, N. Hayashi, H. Hotchi, M. Kinsho, S.I. Meigo, K. Okabe, P.K. Saha, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. Transverse halo monitors, which are horizontal and vertical scanning aluminum plates type, has been installed in the extraction beam line. But the residual secondary electrons hindered the beam halo diagnostic. Thus we develop the new beam halo monitor with vibrating wire monitor.

Slides WEOAA03 [6.701 MB]

WEPPD013

Status of the Vacuum System in J-PARC RCS

2522

J. Kamiya, Y. Hikichi, M. Kinsho, M. Nishikawa, N. Ogiwara, T. Yanagibashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the vacuum system of J-PARC Rapid cycling synchrotron (RCS), we use beam pipes and bellows whose materials are vacuum fired at 700~850 oC in order to eliminate atoms in their bulk who are origin of outgassing. Until now, beam power has been increased up to 300 kW. Pressure in synchrotron beam line increased when the high power beam was accelerated. However, increment of pressure has reduced during the continuous beam operation. It is because the molecules, which adsorb on surface of the wall of the vacuum chambers, desorb by an ion bombardment and a heat generation due to an eddy current. Because the atoms in the bulk is eliminated, desorption of the molecules, which adsorb on the surface, means the reduction of the outgassing from the wall. In this presentation, we will report the past situation of the vacuum system during the beam operation. In addition, we also show the status after the Great East Japan Earthquake.

WEPPR056

Reproduction of Ceramic Chamber Impedances with Electric and Magnetic Polarities of the Ceramics

3051

Y. Shobuda, M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan

In proton synchrotron, ceramic chambers are used as vacuum chambers to avoid the effect on magnetic fields from eddy current excited by the magnetic fields. One of the standard methods of the derivation of the impedances of the ceramic chamber is the field matching technique. In this report, we reproduce the formulae of the ceramic chamber impedance in terms of electric and magnetic polarities. When the beam passes through the chamber, the impedance is mainly excited by the electric polarity of the ceramic.

THPPD051

New Power Supply of the Injection Bump Magnet for Upgrading the Injection Energy in the J-PARC 3-GeV RCS

3626

T. Takayanagi, N. Hayashi, M. Kinsho, N. Tani, T. Togashi, T. Ueno
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

With the energy upgrading of LINAC (Linear accelerator) to 400 MeV in the J-PARC (Japan Proton Accelerator Research Complex), a new power supply of the injection bump magnet has been designed for the 3-GeV RCS (Rapid Cycling Synchrotron). The new power supply is composed with the capacitor bank which has function to form the output current pattern. This power supply is a commutation strategy using the electrical charge and discharge of the capacitor, and the frequency of the switch that becomes the source of the noise is a little. Comparing to the conventional switching-type power supply, this power supply is switched only twice for the pattern formation. Thus, the ripple due to the switching can be expected to be much lower. The 1/16 scale model was manufactured and the characteristics was evaluated. This paper summarizes the design parameter and the experimental result of the new power supply.

THPPP070

Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS

3901

K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, M. Kinsho, R. Saeki, P.K. Saha, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.

THPPP083

Status of J-PARC 3 GeV RCS

3927

M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan

J-PARC RCS have delivered beam progressively since 2008. The RCS ramped up the beam power, and delivered beam of 300kW equivalent and 220kW to MR and MLF, respectively, before the earthquake disaster. The RCS was heavily affected by the last Great East Japan Earthquake. At the RCS, the circulating road went wavy and the yard area for electricity and cooling water devices was heavily distorted. We have investigated damages of each device and also have tried to restore beam operation. From middle of December last year we could start beam test and also would start to deliver beam to MR and MLF for user operation from this January. We have been performed not only recovery works but also improvement of the RCS for realizing high power stable operation with low beam losses. I report status of beam operation and near future plan for the RCS.

Paper	Title	Page
MOPPD053	Reduction of Outgassing from the Ferrite Cores in the Kicker Magnet of J-PARC RCS	487
	N. Ogiwara, Y. Hikichi, J. Kamiya, M. Kinsho, M. Nishikawa, K. Suganuma, T. Yanagibashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Kicker magnets are used to kick out the accelerated beam to the beam transport lines in the RCS of the J-PARC. A high voltage is applied to kickers for a short period, so they must be installed in a vacuum to prevent discharge. Therefore, it is important to reduce the outgassing of water vapor from the ferrite cores. After bake-out at 200°C for 300 hours, the outgassing rate decreased to less than 1×10^-7 Pam/s. However, the small amount of water vapor and carbon monoxide were emitted from the ferrite cores at charging voltage of 80 kV. This time, we have decided to construct the reserve magnets with very low outgassing at high-voltage discharge. First of all, the thermal desorption behavior of the ferrite was investigated. Water vapor has two peaks: at ~ 100°C and 350°C. Carbon monoxide is rather largely emitted until 300°C. From these results, the ferrite cores were vacuum-fired at 450°C for 10 h. Then the good properties for the magnetic cores were confirmed. And now the assembling of the kicker magnet is undertaken. The performance of the kicker magnet made of the vacuum-fired ferrite will be shown in this meeting.

MOPPD073	Development of Transportation System for Low Energy Electron Group	532
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan M. Kinsho, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	There is a time that we want to measure the electron which occurred in the accelerator in the small situation of a noise. In that case, it is one method that we transport these electrons to the place distant form the accelerator where a noise is small. In order to realize that, development of transport line for low energy electrons is required. So, we start to develop transport line using solenoid magnets. We present status of development of this transportation system.

MOPPD074	Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection	535
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

WEOAA03	Development of the Beam Halo Monitor in the J-PARC 3-GeV RCS	2122
	M. Yoshimoto, N. Hayashi, H. Hotchi, M. Kinsho, S.I. Meigo, K. Okabe, P.K. Saha, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. Transverse halo monitors, which are horizontal and vertical scanning aluminum plates type, has been installed in the extraction beam line. But the residual secondary electrons hindered the beam halo diagnostic. Thus we develop the new beam halo monitor with vibrating wire monitor.
	Slides WEOAA03 [6.701 MB]

WEPPD013	Status of the Vacuum System in J-PARC RCS	2522
	J. Kamiya, Y. Hikichi, M. Kinsho, M. Nishikawa, N. Ogiwara, T. Yanagibashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the vacuum system of J-PARC Rapid cycling synchrotron (RCS), we use beam pipes and bellows whose materials are vacuum fired at 700~850 oC in order to eliminate atoms in their bulk who are origin of outgassing. Until now, beam power has been increased up to 300 kW. Pressure in synchrotron beam line increased when the high power beam was accelerated. However, increment of pressure has reduced during the continuous beam operation. It is because the molecules, which adsorb on surface of the wall of the vacuum chambers, desorb by an ion bombardment and a heat generation due to an eddy current. Because the atoms in the bulk is eliminated, desorption of the molecules, which adsorb on the surface, means the reduction of the outgassing from the wall. In this presentation, we will report the past situation of the vacuum system during the beam operation. In addition, we also show the status after the Great East Japan Earthquake.

WEPPR056	Reproduction of Ceramic Chamber Impedances with Electric and Magnetic Polarities of the Ceramics	3051
	Y. Shobuda, M. Kinsho JAEA/J-PARC, Tokai-mura, Japan
	In proton synchrotron, ceramic chambers are used as vacuum chambers to avoid the effect on magnetic fields from eddy current excited by the magnetic fields. One of the standard methods of the derivation of the impedances of the ceramic chamber is the field matching technique. In this report, we reproduce the formulae of the ceramic chamber impedance in terms of electric and magnetic polarities. When the beam passes through the chamber, the impedance is mainly excited by the electric polarity of the ceramic.

THPPD051	New Power Supply of the Injection Bump Magnet for Upgrading the Injection Energy in the J-PARC 3-GeV RCS	3626
	T. Takayanagi, N. Hayashi, M. Kinsho, N. Tani, T. Togashi, T. Ueno JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	With the energy upgrading of LINAC (Linear accelerator) to 400 MeV in the J-PARC (Japan Proton Accelerator Research Complex), a new power supply of the injection bump magnet has been designed for the 3-GeV RCS (Rapid Cycling Synchrotron). The new power supply is composed with the capacitor bank which has function to form the output current pattern. This power supply is a commutation strategy using the electrical charge and discharge of the capacitor, and the frequency of the switch that becomes the source of the noise is a little. Comparing to the conventional switching-type power supply, this power supply is switched only twice for the pattern formation. Thus, the ripple due to the switching can be expected to be much lower. The 1/16 scale model was manufactured and the characteristics was evaluated. This paper summarizes the design parameter and the experimental result of the new power supply.

THPPP070	Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS	3901
	K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, M. Kinsho, R. Saeki, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.

THPPP083	Status of J-PARC 3 GeV RCS	3927
	M. Kinsho JAEA/J-PARC, Tokai-mura, Japan
	J-PARC RCS have delivered beam progressively since 2008. The RCS ramped up the beam power, and delivered beam of 300kW equivalent and 220kW to MR and MLF, respectively, before the earthquake disaster. The RCS was heavily affected by the last Great East Japan Earthquake. At the RCS, the circulating road went wavy and the yard area for electricity and cooling water devices was heavily distorted. We have investigated damages of each device and also have tried to restore beam operation. From middle of December last year we could start beam test and also would start to deliver beam to MR and MLF for user operation from this January. We have been performed not only recovery works but also improvement of the RCS for realizing high power stable operation with low beam losses. I report status of beam operation and near future plan for the RCS.