Research of the Selective Beam Extraction Method for the High Energy Electron Beam in the Storage Ring

在科学研究资助基金(C)的支持下，我们致力于开发从电子同步加速器提取电子束的新方法。实验在京都大学化学研究所电子存储环（KSR）完成。60兆电子伏特的电子束被储存在环内，并成功地以极慢的速度被提取到实验目标。靶处电子束速率约为10^4 e-/秒，萃取周期为1000秒，无新注入。这种新的提取方法利用了电子束与残余气体的散射。通过调节射频横向场和注入束强度来控制抽束速率。结果，光束速率被控制在10^3 e-/sec到10^7 e-/sec之间。这种非常慢的提取光束的应用已经开始。东京大学和KEK的研究小组对液态Xe探测器进行了罕见衰变搜索的测试。日本理化研究所（RIKEN）课题组还完成了“自约束放射性离子靶（SCRIT）”电子探测器的测试。此外，还开展了大阪大学研究组的新型吸管室、京都大学研究组的气凝胶切伦科夫计数器、京都大学研究组的新型微通道板（MCP）束流监测仪等新型探测器的研发项目。

We worked for a development of the new beam extraction method from the electron synchrotron with the support of Grant-in-Aid for Scientific Research (C). The experiments were done at the electron storage ring, KSR at Institute for Chemical Research, Kyoto University. The electron beam of 60 MeV was stored in the ring and successfully extracted very slowly to the experimental target. The electron beam rate was about 10^4 e-/sec at the target and the extraction period was 1000 seconds without new injections. The scattering of the electron beam with the residual gas was utilized in this new extraction method. In order to control the extraction beam rate, the transverse RF field and the injection beam intensity were adjusted. As a result, the beam rate was controlled from 10^3 e-/sec to 10^7 e-/sec.The applications of this very slow extracted beam have already started. The test of the Liquid Xe detector for rare decay search was carried out by the group of Tokyo University and KEK. The test of the electron detectors for "Self-Confining Radioactive ion Target (SCRIT)" was also done by the group of RIKEN. Some R＆D programs of the new detectors were also carried out, such as a new straw chamber by the group of Osaka University, an aerogel Cherenkov Counter by the group of Kyoto University and a new beam monitor using a micro channel plate (MCP)by the group of Kyoto University.