Progress Report on Zero Gradient Synchrotron H- Source Development

The operational reliability required of an H- source for direct or booster injection into a proton synchrotron has been demonstrated during several recent tests of Booster I, the developmental booster for the Zero Gradient Synchrotron (ZGS); the minimum pulsed design current of 4 mA at 50 MeV was obtained for the first time during a recent test of direct H- injection into the ZGS. On the basis of these results and anticipated further improvements in the source, preparations are being made for the permanent installation of a stripper in the ZGS for the conversion of H- to H+. Direct H- injection will become the normal mode of operation, with the 50 MeV beam going to the booster and ZING, an intense neutron generator, in the interval between ZGS pulses. The planned effort through July 31, 1975, calls for an operational tandem-acceleration sequential charge exchange source yielding a 50 MeV H- current of ~ 8 mA. In this source, a low density hydrogen target will serve as a space charge neutralizer and a buffer between the positive ion source and a sodium-vapor charge exchange cell receiving the H+, H0, and H- output from the hydrogen cell. This effort will require a relatively small and conservative extrapolation within the confines of the present state of the art.