High power operation of a 17 GHz photocathode RF gun
- Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
We report the first operation of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. Such electron guns have the potential for achieving record high values of electron beam quality. The 1(1)/(2) cell, {pi}-mode, copper cavity was tested with 5{endash}10 MW, 100 ns, 17.145 GHz pulses from a 24 MW Haimson Research Corp. klystron amplifier. Klystron power is stable to within {plus_minus}5{percent} up to 15 MW. Conditioning resulted in a maximum surface field of 250 MV/m, corresponding to an on-axis gradient of 150 MV/m. Dark current of 0.5 mA was observed at 175 MV/m, consistent with Fowler-Nordheim field emission theory if a field enhancement factor of about 100 is assumed. Electron bunches were generated by a regenerative laser amplifier that produces 2 ps, 1.9 mJ pulses at 800 nm with {plus_minus}10{percent} energy stability. These pulses were frequency tripled to 46 {mu}J of UV, and then focused on the wall of the cavity. Preliminary beam measurements indicate 0.12 nC bunches were produced with a kinetic energy of about 1 MeV. This corresponds to a peak current of about 100 A, and a density at the cathode of 2kA/cm{sup 2}. Both single and multiple pulse laser induced beam emission were observed. {copyright} {ital 1997 American Institute of Physics.}
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-91ER40648
- OSTI ID:
- 580189
- Report Number(s):
- CONF-9610281-; ISSN 0094-243X; TRN: 98:004050
- Journal Information:
- AIP Conference Proceedings, Vol. 398, Issue 1; Conference: 7. advanced accelerator concepts workshop, Lake Tahoe, NV (United States), Oct 1996; Other Information: PBD: Mar 1997
- Country of Publication:
- United States
- Language:
- English
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