SAP2014 - List of Authors (Yang, R.J.)

Paper	Title	Page
WEAMH6	Studies on Factors Affecting the Life-Time of High Average Current GaAs Photocathode	12
	D. Wu, K. Li, M. Li, Q. Pan, H. Wang, D.X. Xiao, R.J. Yang, X. Yang CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	The negative electron affinity (NEA) GaAs photocathode has been demonstrated as an important electron source for high average current accelerators, such as the free electron lasers (FELs) based on energy recovery linacs (ERLs). To increase the life-time of NEA-GaAs, some factors are studied in this paper, such as the vacuum pressure around the cathode, the temperature of the cathode surface and the ion back-bombardment inside DC gun. With these studies, some strategies are applied on the photocathode injector of FEL-THz facility in China Academy of Engineering Physics (CAEP). The cathode working life-time has been improved at least two orders of magnitude.

WEPH14	Ion Tracking in a High-Voltage DC Photo-Gun	58
	R.J. Yang, K. Li, Q. Pan, H. Wang, D. Wu, D.X. Xiao, X. Yang CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	The photocathode lifetime of GaAs in a high voltage DC gun is limited primarily by ion back bombardment. Ions produced in collisions of the electron beam with residual gas in cathode-anode gap and downstream of the anode are accelerated toward the cathode and strike the cathode surface. Systematical studies suggest that ion back bombardment is determined by gas pressure, gun voltage, laser spot and electric field profile. This paper presents a study of ion back bombardment in a high average current DC photocathode gun. This study is based on numerical analysis and particle tracking simulation. The results implies that ion generation can be suppressed by improving vacuum condition as well as gun voltage, and the back bombardment can be reduced by the optimization of laser spot position and electric field profile.

Paper

Title

Page

Studies on Factors Affecting the Life-Time of High Average Current GaAs Photocathode

12

D. Wu, K. Li, M. Li, Q. Pan, H. Wang, D.X. Xiao, R.J. Yang, X. Yang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

The negative electron affinity (NEA) GaAs photocathode has been demonstrated as an important electron source for high average current accelerators, such as the free electron lasers (FELs) based on energy recovery linacs (ERLs). To increase the life-time of NEA-GaAs, some factors are studied in this paper, such as the vacuum pressure around the cathode, the temperature of the cathode surface and the ion back-bombardment inside DC gun. With these studies, some strategies are applied on the photocathode injector of FEL-THz facility in China Academy of Engineering Physics (CAEP). The cathode working life-time has been improved at least two orders of magnitude.

WEPH14

Ion Tracking in a High-Voltage DC Photo-Gun

58

R.J. Yang, K. Li, Q. Pan, H. Wang, D. Wu, D.X. Xiao, X. Yang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

The photocathode lifetime of GaAs in a high voltage DC gun is limited primarily by ion back bombardment. Ions produced in collisions of the electron beam with residual gas in cathode-anode gap and downstream of the anode are accelerated toward the cathode and strike the cathode surface. Systematical studies suggest that ion back bombardment is determined by gas pressure, gun voltage, laser spot and electric field profile. This paper presents a study of ion back bombardment in a high average current DC photocathode gun. This study is based on numerical analysis and particle tracking simulation. The results implies that ion generation can be suppressed by improving vacuum condition as well as gun voltage, and the back bombardment can be reduced by the optimization of laser spot position and electric field profile.