| THP043 粒子源 8月9日 大展示ホール 13:10 - 15:10 |
| CeB6カソードの仕事関数測定装置の開発状況について |
| Development status of the offline work function measurement system for CeB6 cathodes used in the electron gun of SACLA |
| ○馬込 保（高輝度光科学研究センター），渡川 和晃，稲垣 隆宏，原 徹，田中 均（理化学研究所 放射光科学研究センター） |
| ○Tamotsu Magome (JASRI), Kazuaki Togawa, Takahiro Inagaki, Toru Hara, Hitoshi Tanaka (RIKEN SPring-8 Center) |
| A CeB6 thermionic cathode is used for the electron gun of the X-ray free-electron laser, SACLA. A CeB6 thermionic cathode is typically usable for an operation time of one year due to decrease in emission currents. Since work function is the most dominant factor in emission current, we have been developing an offline measurement system for work function of the CeB6 thermionic cathode under simulative conditions of the real electron gun to investigate mechanism of this cathode degradation. The developed system adopts the photoelectron yield spectroscopy using excitation lights from 410 to 709 nm in wavelength generated by a nanosecond tunable Nd:YAG laser system. The CeB6 thermionic cathode is kept in the temperature-limited region with an acceleration voltage of 3 kV DC and a cathode temperature of 1.2E+3 degrees Celsius to reproduce the natural decay of emission current found in the real electron gun. This condition makes it possible to observe a variation of the work function over the cathode degradation. In this paper, we report the development status of the work function measurement system. |