Beam test of multi-bunch energy compensation system in the accelerator test facility at KEK

Shigeru Kashiwagi, Hitoshi Hayano, Kiyoshi Kubo, Timo Korhonen, Shogo Nakamura, Takashi Naito, Katsunobu Oide, Seishi Takeda, Nobuhiro Terunuma, Junji Urakawa

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7 Citations (Scopus)


A beam test of the multi-bunch energy compensation system (ECS) was performed using the AF method with the 2856 ± 4.327MHz accelerating structures in the accelerator test facility (ATF) at KEK. The 1.54GeV S-band linac of the ATF was designed to accelerate a multi-bunch beam that consists of 20 bunches with 2.8 ns spacing. The multi-bunch beam with 2.0 ± 10 10 electrons/bunch has an energy deviation of about 8.5% at the end of the linac due to transient beam loading without ECS. The ATF linac is the injector of the ATF damping ring (DR), whose energy acceptance is ±0.5%. The beam loading compensation system is necessary in the ATF linac for the successful injection of multi-bunch into DR. The rf system of the linac consists of 8 regular rf units with the SLED system and 2 ECS rf units without the SLED system. The accelerating structures of the regular units are driven at 2856 MHz and the 2 ECS structures are operated with slightly different rf frequencies of 2856±4.327 MHz. In the beam test, we have succeeded in compressing the multi-bunch energy spread within the energy acceptance of the DR using ΔF ECS. The principle of the beam loading compensation system of KEK-ATF and the experimental results are described in this paper.

Original languageEnglish
Pages (from-to)5617-5622
Number of pages6
JournalJapanese Journal of Applied Physics
Issue number8 A
Publication statusPublished - 2004 Aug


  • Beam loading
  • Energy compensation
  • Linear collider
  • Multi-bunch beam
  • ΔF method


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