FRPP69 　ポスターセッション③　 9月4日 ポスター会場 10:30-12:30

SuperKEKB における陽電子入射ビームのエミッタンス保存

Emittance preservation of positron injection beam for SuperKEKB

○飯田 直子，菊池 光男，清宮 裕史，森 隆志，紙谷 琢哉，柿原 和久，大越 隆夫，荒木田 是夫，多和田 正文（高エネ研）

○Naoko Iida, Mitsuo Kikuchi, Yuji Seimiya, Takashi Mori, Takuya Kamitani, Kazuhisa Kakihara, Takao Oogoe, Yoshio Arakida, Masafumi Tawada (KEK)

SuperKEKB , a B-factory of electron and positron collider ring, aims for luminosity of 8x10 ^35/cm^2/sec which is about forty times the world's highest record. In order to achieve this luminosity, it is essential that not only the storage beams but also the injected beams have high charges and low emittances. The final required values for the positron injected beam from SuperKEKB are 4nC/bunch with invariant horizontal and vertical emittances of 100 μm, and 15 μm, respectively. The low emittance positron beam after damped through the 1.1 GeV-damping ring is returned to the injector LINAC via a bunch-compression-system, and a beam transport line having four arc sections with an energy-compression-system. It is not so easy to transport the beam to preserve emittances in order of 10μm. It is essential to control the dispersions generated by the arcs and chicanes at the compression cavities, and reduce x-y couplings form the arcs. Currently, the measured emittance of 1 nC beam has been reduced from 450 μm to 150 μm in horizontal, and from 70 μm to 30 μm in vertical. This paper summarizes the corrections made to preserve the emittance of the positron beam.