IPAC2019 - List of Authors (Shimogawa, T.)

Paper	Title	Page
MOPGW036	Studies on Coherent Multi-Bunch Tune Shifts with Different Bunch Spacing at the J-PARC Main Ring	167
	A. Kobayashi, S. Igarashi, Y. Sato, T. Shimogawa, Y. Sugiyama, T. Toyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	At a high-power proton synchrotron, betatron tune shifts induced by space charge effects cause beam loss which limits the beam intensity. To achieve further high beam intensity at the main ring of the Japan Proton Accelerator Research Complex, precise control of the tune shift is indispensable. When carrying out multi-bunch measurements, we observed that the dependence of the tune shift intensity on the number of bunches follow opposite slope trends for the horizontal and vertical directions. The influence of the bunch spacing was also observed. We report on a simplified tune shift model reconstruction for understanding the origin of these phenomena and present a correction of the tune shifts for reducing beam loss up to 30 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW036
About •	paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPMP015	Magnet Power Supply Calibration with a Portable Current Measuring Unit at the J-PARC Main Ring	1263
	K. Miura, Y. Kurimoto, Y. Morita, D. Naito, T. Oogoe, T. Shimogawa KEK, Ibaraki, Japan Y. Kuniyasu Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan K. Ooya SANKYU PLANT TECHNO CO., LTD., 6-5-3, Kachidoki, Japan R. Sagawa Universal Engineering, Ibaraki-ken, Japan
	In the J-PARC MR, 96 bending magnets (BMs) are used in total. They are divided into 6 groups of 16 BMs. The 16 BMs in each group are connected in series and driven by a single power supply. Since all 96 BMs are symmetrically located in the ring, the magnet currents regulated by the 6 power supplies need to be same. Each power supply performs output current feedback control using electronic circuits including analog amplifications and AD / DA conversions. Due to individual differences of the electronic circuits, output current is generally expected to be different for each power supply. Therefore, we developed a current measurement unit with the portable DCCT as an independent reference. Further, we measured the magnet currents regulated by the 6 BM power supplies using the unit. We report the details of the unit as well as the results of the current measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP015
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP016	New Power Supply of Main Magnets for J-Parc Main Ring Upgrade	1266
	T. Shimogawa, Y. Kurimoto, K. Miura, Y. Morita, D. Naito KEK, Ibaraki, Japan R. Sagawa Universal Engineering, Ibaraki-ken, Japan
	It is plans that the proton beam power provided to experimental facilities increase with shortening repetition period in J-PARC Main Ring (MR). As the shorten repetition period, the replacement of the power converters for main magnets in J-PARC MR is necessary to cope with issues such as power fluctuation of the main grid and increase of the output voltage. We have considered and developed the power converters with a 10 MW class which have the capacitor banks with the large capacitance. In the end of 2017, the first new power converter for a bending magnets family, which is the largest power converter in this upgrade plan, was installed in J-PARC site and the power test is ongoing using a dummy and a real load. In this report, the first new power converter for a bending magnets family in J-PARC MR is reported including the test results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP016
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP007	Current Status of Slow Extraction from J-PARC Main Ring	2311
	R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, M. Okada, K. Okamura, T. Shimogawa, Y. Shirakabe, M. Tomizawa, T. Toyama, E. Yanaoka KEK, Ibaraki, Japan A. Matsumura Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan
	A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP007
About •	paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Studies on Coherent Multi-Bunch Tune Shifts with Different Bunch Spacing at the J-PARC Main Ring

167

A. Kobayashi, S. Igarashi, Y. Sato, T. Shimogawa, Y. Sugiyama, T. Toyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

At a high-power proton synchrotron, betatron tune shifts induced by space charge effects cause beam loss which limits the beam intensity. To achieve further high beam intensity at the main ring of the Japan Proton Accelerator Research Complex, precise control of the tune shift is indispensable. When carrying out multi-bunch measurements, we observed that the dependence of the tune shift intensity on the number of bunches follow opposite slope trends for the horizontal and vertical directions. The influence of the bunch spacing was also observed. We report on a simplified tune shift model reconstruction for understanding the origin of these phenomena and present a correction of the tune shifts for reducing beam loss up to 30 %.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW036

About •

paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

TUPMP015

Magnet Power Supply Calibration with a Portable Current Measuring Unit at the J-PARC Main Ring

1263

K. Miura, Y. Kurimoto, Y. Morita, D. Naito, T. Oogoe, T. Shimogawa
KEK, Ibaraki, Japan
Y. Kuniyasu
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
K. Ooya
SANKYU PLANT TECHNO CO., LTD., 6-5-3, Kachidoki, Japan
R. Sagawa
Universal Engineering, Ibaraki-ken, Japan

In the J-PARC MR, 96 bending magnets (BMs) are used in total. They are divided into 6 groups of 16 BMs. The 16 BMs in each group are connected in series and driven by a single power supply. Since all 96 BMs are symmetrically located in the ring, the magnet currents regulated by the 6 power supplies need to be same. Each power supply performs output current feedback control using electronic circuits including analog amplifications and AD / DA conversions. Due to individual differences of the electronic circuits, output current is generally expected to be different for each power supply. Therefore, we developed a current measurement unit with the portable DCCT as an independent reference. Further, we measured the magnet currents regulated by the 6 BM power supplies using the unit. We report the details of the unit as well as the results of the current measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP015

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

TUPMP016

New Power Supply of Main Magnets for J-Parc Main Ring Upgrade

1266

T. Shimogawa, Y. Kurimoto, K. Miura, Y. Morita, D. Naito
KEK, Ibaraki, Japan
R. Sagawa
Universal Engineering, Ibaraki-ken, Japan

It is plans that the proton beam power provided to experimental facilities increase with shortening repetition period in J-PARC Main Ring (MR). As the shorten repetition period, the replacement of the power converters for main magnets in J-PARC MR is necessary to cope with issues such as power fluctuation of the main grid and increase of the output voltage. We have considered and developed the power converters with a 10 MW class which have the capacitor banks with the large capacitance. In the end of 2017, the first new power converter for a bending magnets family, which is the largest power converter in this upgrade plan, was installed in J-PARC site and the power test is ongoing using a dummy and a real load. In this report, the first new power converter for a bending magnets family in J-PARC MR is reported including the test results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP016

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

WEPMP007

Current Status of Slow Extraction from J-PARC Main Ring

2311

R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, M. Okada, K. Okamura, T. Shimogawa, Y. Shirakabe, M. Tomizawa, T. Toyama, E. Yanaoka
KEK, Ibaraki, Japan
A. Matsumura
Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan

A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP007

About •

paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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