Real-Time Beam Loss Monitor Display using FPGA Technology

This paper outlines the design of a Real-time Beam Loss Monitor Display for the ISIS pulsed neutron source based at the Rutherford Appleton Laboratory (Oxon, UK). Synchrotron beam loss is monitored using 39 argon filled ionisation chambers positioned around the synchrotron, the levels of which are sampled four times in each cycle. Four histograms relating to synchrotron beam loss are generated and displayed within each machine cycle (50Hz). Attributes of the new system include setting limits for individual monitors; displaying excursions through limits and freezing the display field on demand. The design is based around a reconfigurable Field Programmable Gate Array (FPGA), interfacing to a TFT monitor via the VGA standard. Results gained using simulated monitor signals have proven the system.