Production and monitoring of short duration beam bursts from the TRIUMF cyclotron

Abstract A stable, phase restricted tune has been developed for the TRIUMF cyclotron. By use of a radially adjustable foil or skimmer on the first turn and a slit on the tenth turn of the machine, the phase acceptance may be reduced from its normal value of approximately 35° to typically 3.7°, corresponding to a beam burst duration of 450 ps FWHM. The beam intensity is reduced by a factor of ten. The time structure of the beam is measured by a time pickoff near the experimental target location. Timing information is derived from protons elastically scattered in a thin in-beam target. The timing pickoff was found to have an intrinsic resolution of 50 ps rms.