Modular variable energy post-accelerator linac

Overview & Synopsis

General outlines of a variable energy linac of modular design are given. It may be characterized by the following topics: 1. The modular conception, which affords the ability for easy extensions, with identical R.F. amplifiers and amplitude and phase control devices. 2. The use of cavities some meters long, the length of which being chosen: a) long enough to use a moderate number of sections, b) short enough to be compatible with: A cheap external focusing, which allows a small outside diameter for the drift tubes and therefore a good shunt-impedance. A good resolution of the energy, the variation of which being obtained by a very simple mean. For instance, 5 such sections, (frequency: 100 MHz, R.F. power: 30 kW, length: 4 m, diameter: 80 cm) are expected to accelerate 40Ca from 1.8 MeV/A to energies comprised between 1.8 and 8 MeV/A with an energy resolution better than 10 -3.