| THP008 ポスター② 8月1日 1F大会議室 13:00-15:00 |
| 発振型FELにおける引き出し効率のシングルショット測定に向けたアレイ型二次電子放出型モニターの開発 |
| Development of array-type secondary electron emission monitor toward single-shot determination of extraction efficiency of oscillator FELs |
| ○畢 壮，田中 虎太郎，全 炳俊，大垣 英明（京大エネ研） |
| ○Zhuang Bi, Kotaro Tanaka, Heishun Zen, Hideaki Ohgaki (IAE, Kyoto Univ.) |
| The extraction efficiency is one of the key parameters of an FEL oscillator. In the conventional way of extraction efficiency measurement in Kyoto University FEL (KU-FEL), temporal evolutions of the electron beam energy distribution in a macro-pulse with and without FEL lasing were measured by a Faraday cup placed after an energy analyzer. Then the extraction efficiency is evaluated from the difference between the instantaneous average energy with and without the FEL lasing. Due to the scanning nature, the conventional way needs a long measurement time. To enable single-shot determination of the extraction efficiency, we developed a monitor that enables us to measure the temporal evolution of the electron beam energy in a macro-pulse by using an array-type secondary electron emission monitor. The monitor consists of 24 ribbon-shaped electrodes and 2 shielding electrodes are placed after the energy analyzer magnet. The beam energy evolutions in a macro-pulse with and without FEL lasing were measured in a single-shot with <100-ns temporal resolution. This monitor will enable single-shot determination of the extraction efficiency of FEL oscillators. |