DIPAC2011 - List of Authors (Toyama, T.)

Paper

Title

Page

Beam Instrumentation in J-PARC

275

T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The talk will summarize the beam instrumentation at J-PARC with a focus on MW class proton beams. The measurements of beam intensities, positions, losses, profiles, and halos at each stage of accelerator, 181 MeV LINAC (to be upgraded to 400MeV), 3 GeV RCS and 50 (30 as phase I) GeV MR will be reported. Present status, including modification and improvement of instrumentations to meet with LINAC energy upgrade and a future plan will be reported with emphasis on high beam power related issues such as radiation hardness (mechanically and electrically), beam coupling impedance, etc..

Slides TUOA01 [22.777 MB]

MOPD08

Beam Diagnostics in the J-PARC Linac for ACS Upgrade

50

A. Miura, S. Sato
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Z. Igarashi, M. Ikegami, T. Miyao, T. Toyama
KEK, Ibaraki, Japan
T. Tomisawa
JAEA/LINAC, Ibaraki-ken, Japan

J-PARC had developed the beam diagnostic devices for the current J-PARC linac and has used them since the operation start. J-PARC linac began the energy upgrade project since 2009 and 21 ACS cavities will be installed. In this project, many cavities and related devices are newly installed in the ACS section and its downstream part. Because the beam parameters are updated, new beam diagnostic devices are fabricated and current diagnostic devices are developed. Beam position monitors (BPM) are newly designed and fabricated, based on the computer simulation and bench test. Because the gas proportional BLMs as the current BLM are sensitive to background noise of X-ray emitted from RF cavities, it is difficult to recognize real beam loss. We need to subtract an X-ray noise from the signal from BLM, another candidate BLMs have been tried to measure the beam loss. In addition, the bunch shape monitor for the longitudinal tuning has been developed in the corroboration with the institute for nuclear research, Russia. In this paper, we describe the new developed devices and their development process, especially for beam loss monitor and the developing bunch shape monitor.

MOPD22

Beam Based Gain Calibration of Beam Position Monitors at J-PARC MR

92

M. Tejima, T. Toyama
KEK, Ibaraki, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

The output data from a beam position monitor (BPM) system usually was calibrated on the test bench and so on. The gain of the output data may drift due to unpredictable imbalance among output signals from the pickup electrodes, because they must travel through separate paths,cables, connectors, attenuators, switches, and then are measured by detectors. The gain calibration has been tried to apply for the BPM system in J-PARC Main Ring. This paper reports the result of beam based gain callibration to estimate the imbalance, which was performed measuring the response from four output data of a BPM head.

TUPD18

Beam Position Monitors for the ACS Section of the J-PARC Linac

341

T. Miyao, Z. Igarashi, T. Toyama
KEK, Ibaraki, Japan
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC is consisted of Linac, 3GeV-RCS, and 50GeV-MR. We are aiming at the energy upgrade of J-PARC linac from 181MeV to 400MeV. We employed the ACS(Annular Coupled Structure) as the acceleration cavities. To have the energy upgrade, we need to develop beam instruments including beam position monitors (BPMs). Then, we designed them to be able to measure a horizontal and vertical beam position and employed a stripline-type as their electrodes. The BPMs are required to be calibrated to the accuracy of beam orbit within 100μm. To achieve the requirement, we did some calibrations. First, we decided a width of stripuline, whose characteristic impedance can be calibrated to 50 Ω with electric field simulations. Second, we also measured characteristic impedance of 4 different striplines per a BPM corresponding with BPM simulations. Last, we measured an electrical center position of BPMs with a simulated beam signal at 324MHz, 6dBm. A BPM will be installed at each quadrupole magnet in the ACS section to be used for a beam commissioning. Systematic calibration of developed BPMs is described in this paper. In addition, a phase measurement using these BPMs will be considered.

TUPD74

The Bunch by Bunch Feedback System in J-PARC Main Ring

482

Y. Kurimoto, Y.H. Chin, T. Obina, M. Tobiyama, T. Toyama
KEK, Ibaraki, Japan
Y. Shobuda
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We report the current status of the bunch by bunch feedback system for the J-PARC Main Ring. The J-PARC Main Ring is the synchrotron accelerating protons from 3 GeV to 30 GeV. It is normally operating at the intensity of 135 kW. The bunch by bunch feedback system have been developed and used for the normal operation of J-PARC Main Ring. The system aims to reduce the coherent transverse oscillation due to the instabilities or injection errors. It consists of a beam position monitor, a stripline kicker and a signal processing electronics. We've observed the injection error leading to the head-tail oscillation and succeed in damping such kind of oscillations and reducing the beam loss significantly.

Poster TUPD74 [1.107 MB]

Paper	Title	Page
TUOA01	Beam Instrumentation in J-PARC	275
	T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The talk will summarize the beam instrumentation at J-PARC with a focus on MW class proton beams. The measurements of beam intensities, positions, losses, profiles, and halos at each stage of accelerator, 181 MeV LINAC (to be upgraded to 400MeV), 3 GeV RCS and 50 (30 as phase I) GeV MR will be reported. Present status, including modification and improvement of instrumentations to meet with LINAC energy upgrade and a future plan will be reported with emphasis on high beam power related issues such as radiation hardness (mechanically and electrically), beam coupling impedance, etc..
	Slides TUOA01 [22.777 MB]

MOPD08	Beam Diagnostics in the J-PARC Linac for ACS Upgrade	50
	A. Miura, S. Sato JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Z. Igarashi, M. Ikegami, T. Miyao, T. Toyama KEK, Ibaraki, Japan T. Tomisawa JAEA/LINAC, Ibaraki-ken, Japan
	J-PARC had developed the beam diagnostic devices for the current J-PARC linac and has used them since the operation start. J-PARC linac began the energy upgrade project since 2009 and 21 ACS cavities will be installed. In this project, many cavities and related devices are newly installed in the ACS section and its downstream part. Because the beam parameters are updated, new beam diagnostic devices are fabricated and current diagnostic devices are developed. Beam position monitors (BPM) are newly designed and fabricated, based on the computer simulation and bench test. Because the gas proportional BLMs as the current BLM are sensitive to background noise of X-ray emitted from RF cavities, it is difficult to recognize real beam loss. We need to subtract an X-ray noise from the signal from BLM, another candidate BLMs have been tried to measure the beam loss. In addition, the bunch shape monitor for the longitudinal tuning has been developed in the corroboration with the institute for nuclear research, Russia. In this paper, we describe the new developed devices and their development process, especially for beam loss monitor and the developing bunch shape monitor.

MOPD22	Beam Based Gain Calibration of Beam Position Monitors at J-PARC MR	92
	M. Tejima, T. Toyama KEK, Ibaraki, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	The output data from a beam position monitor (BPM) system usually was calibrated on the test bench and so on. The gain of the output data may drift due to unpredictable imbalance among output signals from the pickup electrodes, because they must travel through separate paths,cables, connectors, attenuators, switches, and then are measured by detectors. The gain calibration has been tried to apply for the BPM system in J-PARC Main Ring. This paper reports the result of beam based gain callibration to estimate the imbalance, which was performed measuring the response from four output data of a BPM head.

TUPD18	Beam Position Monitors for the ACS Section of the J-PARC Linac	341
	T. Miyao, Z. Igarashi, T. Toyama KEK, Ibaraki, Japan A. Miura JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC is consisted of Linac, 3GeV-RCS, and 50GeV-MR. We are aiming at the energy upgrade of J-PARC linac from 181MeV to 400MeV. We employed the ACS(Annular Coupled Structure) as the acceleration cavities. To have the energy upgrade, we need to develop beam instruments including beam position monitors (BPMs). Then, we designed them to be able to measure a horizontal and vertical beam position and employed a stripline-type as their electrodes. The BPMs are required to be calibrated to the accuracy of beam orbit within 100μm. To achieve the requirement, we did some calibrations. First, we decided a width of stripuline, whose characteristic impedance can be calibrated to 50 Ω with electric field simulations. Second, we also measured characteristic impedance of 4 different striplines per a BPM corresponding with BPM simulations. Last, we measured an electrical center position of BPMs with a simulated beam signal at 324MHz, 6dBm. A BPM will be installed at each quadrupole magnet in the ACS section to be used for a beam commissioning. Systematic calibration of developed BPMs is described in this paper. In addition, a phase measurement using these BPMs will be considered.

TUPD74	The Bunch by Bunch Feedback System in J-PARC Main Ring	482
	Y. Kurimoto, Y.H. Chin, T. Obina, M. Tobiyama, T. Toyama KEK, Ibaraki, Japan Y. Shobuda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We report the current status of the bunch by bunch feedback system for the J-PARC Main Ring. The J-PARC Main Ring is the synchrotron accelerating protons from 3 GeV to 30 GeV. It is normally operating at the intensity of 135 kW. The bunch by bunch feedback system have been developed and used for the normal operation of J-PARC Main Ring. The system aims to reduce the coherent transverse oscillation due to the instabilities or injection errors. It consists of a beam position monitor, a stripline kicker and a signal processing electronics. We've observed the injection error leading to the head-tail oscillation and succeed in damping such kind of oscillations and reducing the beam loss significantly.
	Poster TUPD74 [1.107 MB]