An intelligent HV control and monitoring system for the PHENIX Hadron Blind Detector at the relativistic heavy ion collider

The PHENIX Hadron Blind Detector (HBD) is a high-performance Cherenkov counter used to detect electrons in relativistic heavy ion collisions at RHIC. A High Voltage Control and Monitoring System (HVC) was developed to provide optimal control over the detector for maximal performance and protection against damage from possible discharges. The HVC comprises several novel hardware components including a voltage divider board and trip detection/protection boards for each power supply module, while actual control of the HV is maintained by a software suite which incorporates Modern Optimal Control Theory and Artificial Intelligence concepts. The software suite is made up of several concurrently operating subsystems, which periodically processes measurements fed back from the HV mainframe, the HBD gas pressure (P) and temperature (T) sensors, analyzes the GEM module behavior in reference to its performance over time, determines a custom response and modifies the HV when necessary. Since the HBD gain is very sensitive to P/T fluctuations, the HVC automatically modifies the GEM/Mesh voltage accordingly in order to keep the gain variations within a nominal operating range of +/- 10%. Both hardware and software components of the HVC will be described, along with the successful performance results throughout the commissioning p+p Run-9 and the HBD's final and most important Au+Au Run-10.