A MICROPULSE MONITOR FOR CONTROL OF CYCLOTRON BEAMS

A system using wall current monitors to observe the time structure of the individual beam current pulses of the Cyclotron Corp. CV28 cyclotron installed at the Instituto de Engenharia Nuclear of CNEN in Rio de Janeiro is described. The monitors are designed to give a faithful representation of the actual beam pulse, so the effects on the longitudinal phase space could be seen as the cyclotron parameters were changed. Beam pulses of width in the range of 1 to 4 ns and with a charge of 7 × 10-16 C or greater can be observed. With two units in the line transit times permit beam energy determination as well as charge distribution. For timing purposes a unit placed in front of a target is used to generate a start signal for time-of-flight measurements, and to monitor the effects of all parameters of the cyclotron tune. By measuring flight times in the beamlines of this machine, the energy for 28 MeV protons can be determined to about 50 keV and for the other available particles to about 30 keV. © 1990.