Effect of ion excape velocity and conversion surface material on H- production
- Los Alamos National Laboratory
- UNIV OF JYVASKYLA
- UNIV OF JYASKYLA
- ORNL
According to generally accepted models surface production of negative ions depends on ion escape velocity and work function of the surface. We have conducted an experimental study addressing the role of the ion escape velocity on H{sup -} production. A converter-type ion source at Los Alamos Neutron Science Center was employed for the experiment. The ion escape velocity was changed by varying the bias voltage of the converter electrode. It was observed that due to enhanced stripping of H{sup -} no direct gain of extracted beam current can be achieved by increasing the converter voltage. At the same time the conversion efficiency of H{sup -} was observed to vary with converter voltage and follow the existing theories in qualitative manner. We discuss the role of surface material on H{sup -} formation probability and present calculations predicting relative H{sup -} yields from different cesiated surfaces. These calculations are compared with experimental observations from different types of H{sup -} ion sources. The effects caused by varying cesium coverage are also discussed. Finally, we present a novel idea of utilizing materials exhibiting so-called negative electron affinity in H{sup -}/D{sup -} production under UV-light exposure.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1036725
- Report Number(s):
- LA-UR-10-06737; LA-UR-10-6737; TRN: US1201464
- Resource Relation:
- Conference: 2nd International Symposium on Negative Ions, Beams and Sources ; November 16, 2010 ; Takayama Gifu, Japan
- Country of Publication:
- United States
- Language:
- English
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