Digital Computer Control of the Bevatron Inflection System

A program is being carried out at the Bevatron, in cooperation with the 200-BeV Design Study,1 to investigate the application of computerized digital control to accelerators. Specifically, a digital-computer control system has been placed in operation at the Bevatron injector for investigation of control and operator interaction between an on-line control computer and an operating accelerator. The system controls transport and inflection of the 19.3 proton beam. The computer, which is remotely located from the accelerator, collects and disseminates control information through time-shared, hybrid (analog -- digital) interface hardware. Data transmission is via twisted pair cable. With this system the beam´s center of gravity has been maintained at the entrance of the achromatic inflector, in the transverse planes, to ±0.1 mm and ±0.1 mrad2 by closed-loop sampled-data control of steering magnets at three points along the beam-transport channel. Beam-position information is obtained from 200-MHz resonant induction electrodes3 located near each steering magnet. In addition, the inflector deflection and focussing elements may be set by the operator and then regulated automatically by the computer. The operator may request typewritten or cathode-ray-tube (CRT) alphanumeric display or a CRT plot of parameters of interest. Optimization of the circulating charge in the accelerator by automatic adjustment of the inflector magnets and on-line diagnostics of certain injector components during trouble periods are planned.