Beam current measurements for LEDA

Beam diagnostics systems for the Low Energy Demonstrator Accelerator (LEDA) at Los Alamos include beam current measurements. The LEDA machine operates in both pulsed and CW modes with a peak current of 100 mA. Two types of current sensors are employed. Some are DC- to 4-kHz-bandwidth modular parametric current transformer (MPCT) sensors from Bergoz(R) and the others are 10-Hz to 200-kHz bandwidth custom-designed transformers. Both AC and DC sensors are integrated into common shielding enclosures on the beam line. A VXI module has been developed to interface the analog sensors to the EPICS control system. The same VXI module can be used for either type of sensor and contains an on-board calibration system which provides a system absolute accuracy of /spl plusmn/0.2%. The calibration, data processing, and general operation of the VXI module is controlled by two internal DSP modules. The performance of the system on the LEDA beam line is presented.