MEASUREMENTS OF DISCHARGE PARAMETERS OF THE ION-SOURCE AT HIGH-POTENTIAL

The present measurement system is composed of signal preprocessors, an A/D conversion card, optical fibers, a microcomputer, and an interfac e. After discharge parameters of an ion source at high potential, i.e. , analog signals, are preprocessed by means of LPF, amplitude limit, a nd normalization, they are changed into digital signals by A/D convers ion. The digital signals are transferred through optical fibers to low potential, then they are gathered, processed, or stored by the microc omputer. The system can measure eight analog signals at high potential through scanning. Each measurement will take about 160 mus with a pre cision of +/-1 LSB, i.e., +/-0.4% maximum relative error at full range . Measurements of discharge parameters of the ion source at high poten tial were made for a steady state ion source and a high current pulse ion source successively, whose results are in good agreement with prac tical cases. The formation and propagation of interference and approac hes of anti-interference under high current and high pulse voltage con ditions are briefly described in the present article.