Multi-kiloampere, electron-beam generation from bare aluminum photo-cathodes driven by an ArF laser
- Los Alamos National Lab., NM (United States)
- Mission Research Corp., Albuquerque, NM (United States)
An electron-beam-pumped laser operating at ArF (193 nm) producing up to 5.0 joules in a 150-ns pulse has been used to illuminate micro-machined aluminum cathodes. The cathode was pulsed from 2.25- up to 2.95-MV across a 20-cm-AK gap producing fields up to 145 kV/cm using REX (a 4-MeV, 5-kA, 100-ns pulsed diode). Extracted current versus laser power gives a quantum efficiency increasing with power density from 0.07 to 0.11%. The present work is significant in that the cathode operates in the presence of out-gassing materials with a background vacuum pressure in the mid 10{sup {minus}6} torr region and 100-ns-long electron beams of up to 3 kA have been produced. Both emission limited (current follows laser pulse) and space-charge-limited (current follows pulsed power) regimes have been studied up to {approximately} 50 A/cm{sup 2} by varying the cathode diameter. The beam temperature has been measured to be < 5 eV and directly compared in the same experimental setup to velvet based cathodes that measure {approximately} 100 eV.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 532549
- Report Number(s):
- LA-UR-97-1664; CONF-970503-222; ON: DE97008182; TRN: 97:019442
- Resource Relation:
- Conference: 17. IEEE particle accelerator conference, Vancouver (Canada), 12-16 May 1997; Other Information: PBD: [1997]
- Country of Publication:
- United States
- Language:
- English
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