Beam separation experiment with prototype non-destructive electrostatic septum and study for device improvement

Nagayama, Shota; Harada, Hiroyuki  ; Shimogawa, Tetsushi*; Sato, Atsushi*; Yamada, Ippei ; Chimura, Motoki ; Kojima, Kunihiro ; Yamamoto, Kazami   ; Kinsho, Michikazu  

We have been developing "Non-destructive electrostatic septum" for a slow extraction. This septum has multiple electrodes placed around the region without the beam hitting and separate the beam by its electric field. To evaluate its electric field, we have built a prototype septum and a test machine, which consists of an electron gun and monitors. This test machine can measure the electric field indirectly by using a narrow electron beam. The experiment results of prototype septum is good agreement with the calculation one. However, this electric field distribution is not enough to separate the beam. A step function-like electric field distribution is ideal for the beam separation with minimal negative effect on the beam. We have studied to improve the electrode configuration to match the beam shape. In this paper, we present the result of the electric field measurements and the septum improvement. Additionally, we describe the future plan of this development.