Injected Beam Chopper System for the Intense Pulsed Neutron Source Accelerator System

A new chopper system has been designed and built to allow versatile manipulation of the H- beam for the Intense Pulsed Neutron Source (IPNS) accelerator system. The beam is chopped at an energy of 750 keV, just before injection into the 50 MeV linear accelerator. The system consists of a high speed logic control system, a high power pulse amplifier and a travelling wave beam deflection electrode. The control system allows for up to four concurrently operable functions. The first mode is dedicated to personnel and equipment protection interlocking. The second is for low frequency pulse shaping. The third is a high frequency chop mode for RF synchronized injection of the 50 MeV beam into the Rapid Cycling Synchrotron (RCS). The fourth mode allows width and/or time modulation of the RF synchronized chopping to control the loading of the RF bucket area in the RCS.