Some Considerations in Planning for Superhilac Timeshare Operation with Both Heavy and Light Ion Beams

One of the important problems to be solved for any accelerator, with the exception of those intended for a single purpose such as injection, is providing adequately for multiple use of the machine. Of particular importance is the possibility of timeshare operation, in which two or more experimental setups can be supplied with beam at the same time. The SuperHilac will accelerate ions of all mass numbers, with final energy continuously variable from 2.6 to 8.5 MeV/nucleon. Normally, to change particle and energy in the Hilac requires a careful retuning of many machine parameters and (optimistically) an hour of machine time. For the SuperHilac it is proposed to provide particles of different charge-to-mass ratio on alternate pulses, so that, for example, half of the pulses would be light ions, delivered to one experimental area, and the other half heavy ions, delivered to another experimental area. Consequently a number of new problems need to be solved. These occur at injection, with accelerating and focusing the beams in the linac, in the stripper area, and at the exit from the machine.