IPAC2014 - List of Authors (Ishii, K.)

Paper	Title	Page
MOPME069	Upgrade of the Injection Kicker System for J-PARC Main Ring	526
	T. Sugimoto, K. Fan, K. Ishii, H. Matsumoto KEK, Ibaraki, Japan
	Four lumped inductance injection kicker magnets for the J-PARC main ring (MR) produce a kick of 0.1096 T·m with a 1% to 99% rise-time of about 400 nsec. A residual field of about 6% of the flat-top exists at the tail of the pulse due to an impedance mismatching. The residual field is required to be suppressed less than 1% to reduce injection losses. For a higher intensity beam operation, the kicker rise-time of less than 300nsec is required to inject longer beam bunches which reduces a space charge effect. During the long shutdown in FY2013, 140Ω resistor and 7nF capacitor were connected to the thyratron to improve the post-pulse shape. In addition, an optimization of a capacitance in the matching circuit was carried out to optimize the waveform. As the result, the rise-time of 195nsec and the residual tail field of 2% were achieved. However, another reflection peak of about 9% is appeared. We plan to compensate the effect of the new peak by using a new small kicker magnet. This paper discusses the detail of the circuit and the beam test results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME069
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MOPRI089	Upgrade of J-PARC Fast Extraction System	821
	K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan T. Shibata JAEA, Ibaraki-ken, Japan
	The J-PARC main ring (MR) fast extraction (FX) system has two functions: to deliver a high power beam to the neutrino experimental facility and to dump the beam at any time in case of hardware failures. The present FX system consists of five bipolar kickers and eight bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, two high performance eddy current septa have been designed and fabricated. Then downstream high field septa are redesigned and using ceramic beam pipe to eliminate eddy current effects, which meets the requirement of high repetition rate operation. A new large physical aperture quadrupole is needed to accommodate high intensity beam. In order to evaluate the beam loss in the new system, realistic 3D beam tracking is studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI089
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WEPRO065	New Design of J-PARC Main Ring Injection System for High Beam Power Operation	2097
	K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, T. Shibata, T. Sugimoto KEK, Ibaraki, Japan
	The present J-PARC main ring (MR) injection system has worked for 6 years since 2008, and the performance has been improved a lot by correcting the original design faults. But there are still problems in the existing injection system that affects the daily operation. In order to realize the MR beam power to the design limit, a high performance injection system is crucial. The remaining problems may have severe effects on high intensity beam, and become a big block to the realization of high beam power operation. Thus, upgrade the present injection system to satisfy the demands of high beam power operation is extremely important. The upgrade will redesign injection septa to obtain high performance, which will reduce the leakage field greatly. The kicker rise time will be reduced greatly by optimizing the configuration and using speed-up circuit. A compensation kicker magnet is being studied for reflection tail field cancelation. Careful 3D electromagnetic field simulations and 3D particle tracking are performed to ensure the accuracy of magnets design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO065
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Paper

Title

Page

Upgrade of the Injection Kicker System for J-PARC Main Ring

526

T. Sugimoto, K. Fan, K. Ishii, H. Matsumoto
KEK, Ibaraki, Japan

Four lumped inductance injection kicker magnets for the J-PARC main ring (MR) produce a kick of 0.1096 T·m with a 1% to 99% rise-time of about 400 nsec. A residual field of about 6% of the flat-top exists at the tail of the pulse due to an impedance mismatching. The residual field is required to be suppressed less than 1% to reduce injection losses. For a higher intensity beam operation, the kicker rise-time of less than 300nsec is required to inject longer beam bunches which reduces a space charge effect. During the long shutdown in FY2013, 140Ω resistor and 7nF capacitor were connected to the thyratron to improve the post-pulse shape. In addition, an optimization of a capacitance in the matching circuit was carried out to optimize the waveform. As the result, the rise-time of 195nsec and the residual tail field of 2% were achieved. However, another reflection peak of about 9% is appeared. We plan to compensate the effect of the new peak by using a new small kicker magnet. This paper discusses the detail of the circuit and the beam test results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI089

Upgrade of J-PARC Fast Extraction System

821

K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
T. Shibata
JAEA, Ibaraki-ken, Japan

The J-PARC main ring (MR) fast extraction (FX) system has two functions: to deliver a high power beam to the neutrino experimental facility and to dump the beam at any time in case of hardware failures. The present FX system consists of five bipolar kickers and eight bipolar septa. In order to raise the beam power to the design limit, both the beam intensity and the repetition rate will increase gradually. The FX system needs to be upgraded to satisfy the new requirements. The upgrade includes FX orbit optimization and new design of devices. Firstly, two high performance eddy current septa have been designed and fabricated. Then downstream high field septa are redesigned and using ceramic beam pipe to eliminate eddy current effects, which meets the requirement of high repetition rate operation. A new large physical aperture quadrupole is needed to accommodate high intensity beam. In order to evaluate the beam loss in the new system, realistic 3D beam tracking is studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI089

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO065

New Design of J-PARC Main Ring Injection System for High Beam Power Operation

2097

K. Fan, K. Ishii, H. Matsumoto, N. Matsumoto, T. Shibata, T. Sugimoto
KEK, Ibaraki, Japan

The present J-PARC main ring (MR) injection system has worked for 6 years since 2008, and the performance has been improved a lot by correcting the original design faults. But there are still problems in the existing injection system that affects the daily operation. In order to realize the MR beam power to the design limit, a high performance injection system is crucial. The remaining problems may have severe effects on high intensity beam, and become a big block to the realization of high beam power operation. Thus, upgrade the present injection system to satisfy the demands of high beam power operation is extremely important. The upgrade will redesign injection septa to obtain high performance, which will reduce the leakage field greatly. The kicker rise time will be reduced greatly by optimizing the configuration and using speed-up circuit. A compensation kicker magnet is being studied for reflection tail field cancelation. Careful 3D electromagnetic field simulations and 3D particle tracking are performed to ensure the accuracy of magnets design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO065

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)