LINAC2014 - List of Authors (Fang, Z.)

Paper	Title	Page
MOPP072	Present Status of J-PARC LINAC LLRF Systems	224
	Z. Fang, Y. Fukui, K. Futatsukawa, T. Kobayashi, S. Michizono KEK, Ibaraki, Japan E. Chishiro, F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	The RF control systems have been developed for the J-PARC proton linac, which consists of 324-MHz and 972-MHz acceleration sections. From October 2006, we started the commissioning of the 324-MHz sections. Then the J-PARC 324-MHz 181-MeV proton linac had been operated nearly for 7 years, until May 2013. In the summer of 2013, we upgraded the J-PARC linac by adding 972-MHz acceleration sections. The output energy of the J-PARC linac was successfully upgraded to 400 MeV in December 2013, and then the operation of the J-PARC 400-MeV linac started. In the past 8 years of the J-PARC linac operation, no heavy troubles occurred in the RF control systems. Every year we made improvements on the RF control systems, according to the operation experiences. In this paper, the present status of the J-PARC 400-MeV linac RF control systems will be described in details, and an improvement plan for the LLRF systems in the future will also be introduced.

TUPP067	Chopper Operation for the Tandem Scrapers at the J-PARC Linac	581
	K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono KEK, Ibaraki, Japan E. Chishiro, K. Hirano, F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	In the J-PARC linac, the energy upgrade from 181 MeV to 400 MeV by the installation of annular-ring coupled structure (ACS) cavities was successfully achieved in 2013. In the next stage, we will schedule the intensity upgrade by the increase of the beam current by improving the front-end in this summer. Then, the high heat load of the scraper, which stops the kicked-beam by the RF chopper, is predicted to damage the surface. Therefore, we prepare the tandem scrapers to suppress the heat load. The half of the kicked beam leads to a scraper and the residual is to the other. Its chopping expedient will be achieved by reversing the phase of the RF chopper on the periodic cycle at the low-level RF system. In this paper, I would like to introduce this system and present the result of the low-level test.

THPP089	High Power Conditioning of Annular-Ring Coupled Structures for the J-PARC Linac	1053
THPOL07	use link to see paper's listing under its alternate paper code
	H. Ao, T. Ito, Y. Nemoto, H. Oguri, N. Ouchi, J. Tamura JAEA/J-PARC, Tokai-mura, Japan H. Asano Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan Z. Fang, K. Futatsukawa, K. Nanmo, T. Sugimura KEK, Ibaraki, Japan
	The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to a 3-GeV synchrotron, comprised a 3-MeV RFQ, 50-MeV DTLs and 181-MeV Separated-type DTLs. From September 2013, 25 annular-ring coupled structure (ACS) cavities were additionally installed to increase the linac beam energy up to 400 MeV and achieve 1-MW beam power of the 3-GeV synchrotron. After installation work the high power conditioning was started from December 2013 and most of the ACS cavities were conditioned within three weeks. We passed through some troubles and finally finished conditioning all the cavities until the middle of January 2014. In this paper, we present the conditioning results and how to handle the issue in the conditioning process.
	Slides THPP089 [7.756 MB]

Paper

Title

Page

Present Status of J-PARC LINAC LLRF Systems

224

Z. Fang, Y. Fukui, K. Futatsukawa, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
E. Chishiro, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

The RF control systems have been developed for the J-PARC proton linac, which consists of 324-MHz and 972-MHz acceleration sections. From October 2006, we started the commissioning of the 324-MHz sections. Then the J-PARC 324-MHz 181-MeV proton linac had been operated nearly for 7 years, until May 2013. In the summer of 2013, we upgraded the J-PARC linac by adding 972-MHz acceleration sections. The output energy of the J-PARC linac was successfully upgraded to 400 MeV in December 2013, and then the operation of the J-PARC 400-MeV linac started. In the past 8 years of the J-PARC linac operation, no heavy troubles occurred in the RF control systems. Every year we made improvements on the RF control systems, according to the operation experiences. In this paper, the present status of the J-PARC 400-MeV linac RF control systems will be described in details, and an improvement plan for the LLRF systems in the future will also be introduced.

TUPP067

Chopper Operation for the Tandem Scrapers at the J-PARC Linac

581

K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
E. Chishiro, K. Hirano, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In the J-PARC linac, the energy upgrade from 181 MeV to 400 MeV by the installation of annular-ring coupled structure (ACS) cavities was successfully achieved in 2013. In the next stage, we will schedule the intensity upgrade by the increase of the beam current by improving the front-end in this summer. Then, the high heat load of the scraper, which stops the kicked-beam by the RF chopper, is predicted to damage the surface. Therefore, we prepare the tandem scrapers to suppress the heat load. The half of the kicked beam leads to a scraper and the residual is to the other. Its chopping expedient will be achieved by reversing the phase of the RF chopper on the periodic cycle at the low-level RF system. In this paper, I would like to introduce this system and present the result of the low-level test.

THPP089

High Power Conditioning of Annular-Ring Coupled Structures for the J-PARC Linac

1053

THPOL07

use link to see paper's listing under its alternate paper code

H. Ao, T. Ito, Y. Nemoto, H. Oguri, N. Ouchi, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
H. Asano
Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
Z. Fang, K. Futatsukawa, K. Nanmo, T. Sugimura
KEK, Ibaraki, Japan

The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to a 3-GeV synchrotron, comprised a 3-MeV RFQ, 50-MeV DTLs and 181-MeV Separated-type DTLs. From September 2013, 25 annular-ring coupled structure (ACS) cavities were additionally installed to increase the linac beam energy up to 400 MeV and achieve 1-MW beam power of the 3-GeV synchrotron. After installation work the high power conditioning was started from December 2013 and most of the ACS cavities were conditioned within three weeks. We passed through some troubles and finally finished conditioning all the cavities until the middle of January 2014. In this paper, we present the conditioning results and how to handle the issue in the conditioning process.

Slides THPP089 [7.756 MB]