Experimental study of a simple method to chop Penning SPS H{sup {minus}} beams
Accumulator rings proposed for use in high-intensity spallation-neutron sources require a chopped beam with particle-free gaps {approx}100 ns wide at 1--2 MHz rates with rise and fall times {le} 20 ns. Chopping the beam directly in the ion source may be an attractive way to provide the desired beam structure. A grounded collar placed in the drift region next to the emission aperture lowers the e{sup {minus}}/H{sup {minus}} ratio in the 8X source H{sup {minus}} beam. We electrically isolated the collar and biased it to modulate the extracted H{sup {minus}} current. Positive collar bias decreases the H{sup {minus}} beam by up to 90%. The fastest H{sup {minus}} current fall and rise times achieved to date are 400 ns and 2 {mu}s, respectively. The fall time is close to the pulser rise time ({approx}300 ns). The rise time is considerably longer than the pulser fall time ({approx}500 ns). Negative collar bias lowers the H{sup {minus}} beam by up to 50%.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10171484
- Report Number(s):
- LA-UR-94-2662; CONF-9408125-2; ON: DE94016189
- Resource Relation:
- Conference: 17. international LINAC conference,Tsukuba (Japan),21-26 Aug 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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