skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Versatile H/sup +/ beam chopper system at LAMPF

Conference ·
OSTI ID:6316678

The H/sup +/ chopper system at LAMPF provides two modes (A and B) of beam chopping. Mode A provides single micropulses separated by 1 ..mu..s or more. Mode B provides a single pulse 50-ns to 10-..mu..s long at the LAMPF repetition rate of 12 Hz. The mode of operation is selected with coaxial relays which can switch during the dead time between LAMPF macropulses. The chopper consists of 1-m-long push-pull helical-wound slow-wave deflecting structures having an axial pulse velocity of 0.04c, which matches the velocity of the proton beam. The helix ground-planes are biased by a pulser providing push-pull 500-V pulses to deflect the H/sup +/ beam from the injection channel. In chopping mode A, the helical windings are driven by push-pull, 1000-V, 5-ns pulses delivered by a circuit utilizing avalanche transistors and planar triodes. In mode B, the helical windings are driven by push-pull, 1000-V, 50-ns to 10-..mu..s long pulses, produced by a circuit utilizing beam-power tetrodes and fast SCRs. In both modes, these pulses cancel the ground-plane bias and permit beam pulses to be delivered to the linac.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
6316678
Report Number(s):
LA-UR-79-708; CONF-790327-28; TRN: 79-011467
Resource Relation:
Conference: IEEE particle accelerator conference, San Francisco, CA, USA, 12 Mar 1979
Country of Publication:
United States
Language:
English