vacuum characteristics of the dtl and sdtl cavities …

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Proceedings of the4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meeting in Japan (August 1-3, 2007, Wako Japan) VACUUM CHARACTERISTICS OF THE DTL AND SDTL CAVITIES FOR J-PARC EXCITED WITH HIGH-POWER RF Hiroyuki Asano A) , Shozo Anami B) , Takashi Itou A) , Masato Kawamura B) , Chikashi Kubota B) , Tetsuya Kobayashi A) , Hiroyuki Suzuki A) , Hirokazu Tanaka B) , Etsuji Chishiro A) , Fujio Naito 1,B) , Kesao Nanmo B) , Zhigao Fang B) , Yuji Fukui B) , Toshihiko Hori A) , Masayoshi Yamazaki A) , Seiya Yamaguchi B) , A) Japan Atomic Energy Agency (JAEA) 2-4 Shirane, Shirakata, Tokai-mura, Ibaraki, 319-1195 B) High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba-shi, Ibaraki, 305-0801 Abstract The main component of the linac of J-PARC consists of three DTL and 32 SDTL cavities. Therefore the stability of the linac system strongly depends on the property of the cavities. As far as we know, the vacuum level of the tank is one of a good measure of the cavity condition. Since the variation of the cavity vacuum level is caused by the cavity structure and also the RF power level supplied to the cavity, we have measured the power dependence of the vacuum level of the cavity systematically after the basic conditioning for the cavities. J-PARC DTL SDTL 1 E-mail: [email protected] SDTL -437-

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Proceedings of the4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meeting in Japan (August 1-3, 2007, Wako Japan)

VACUUM CHARACTERISTICS OF THE DTL AND SDTL CAVITIES FORJ-PARC EXCITED WITH HIGH-POWER RF

Hiroyuki AsanoA), Shozo AnamiB), Takashi ItouA), Masato KawamuraB), Chikashi KubotaB), Tetsuya KobayashiA),Hiroyuki SuzukiA), Hirokazu TanakaB), Etsuji ChishiroA), Fujio Naito1,B), Kesao NanmoB), Zhigao FangB),

Yuji FukuiB), Toshihiko HoriA), Masayoshi YamazakiA), Seiya YamaguchiB),A) Japan Atomic Energy Agency (JAEA)

2-4 Shirane, Shirakata, Tokai-mura, Ibaraki, 319-1195B) High Energy Accelerator Research Organization (KEK)

1-1 Oho, Tsukuba-shi, Ibaraki, 305-0801

Abstract

The main component of the linac of J-PARC consists of three DTL and 32 SDTL cavities. Therefore the stability ofthe linac system strongly depends on the property of the cavities. As far as we know, the vacuum level of the tank isone of a good measure of the cavity condition. Since the variation of the cavity vacuum level is caused by thecavity structure and also the RF power level supplied to the cavity, we have measured the power dependence of thevacuum level of the cavity systematically after the basic conditioning for the cavities.

J-PARC DTL SDTL

1 E-mail: [email protected]

SDTL

-437-

Proceedings of the4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meeting in Japan (August 1-3, 2007, Wako Japan)

-

< 50kW 200 800kW

3.1 DTL

4 DTLD1 0.1MW 0.8~1.1MW

D2 0.1MW0.7~0.9MW D1

D30.4~0.6MW

D1=0.9MW, D2=1.1MW, D3=1.0MW

4DTL E0=2 2.5MV/m

E0=0.5MV//m

[2]E0 0.5MV/m E0

2.0MV/m

SDTL1 2

DTL

DTL

DTL-1

-438-

Proceedings of the4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meeting in Japan (August 1-3, 2007, Wako Japan)

3.2 SDTL

33.5MV/m

DTL

DTL SDTLDTL

SDTL

SDTL

152mm66mm 43mm

V P P[w]=V2/Z (Z=50)

P=110 500kW

SDTL 100 200kW

3 3.5MV/mDTL

J PARC DTLSDTL

DTL 2.0 2.5MV/m

SDTL2

DTL

[1] Y. Yamazaki, “STATUS OF THE J-PARC LINAC,INITIAL RESULTS AND UPGRADE PLAN”, Proc. ofLINAC 2004, Lübeck, Germany (2004) 554

[2] Albert J. Hatch and H. Bartel Williams, “MulipactingModes of High-Frequency Gaseous Breakdown”, Phys.Rev. Vol. 112 (1958) 681.

SDTL

SDTL

-439-