All the detector elements require the use of High Voltage. The high voltage supplies for the detectors are located in the electronics room of the counting house. During experiments the control of the high voltage supplies is done via computer and a display is available on one of the xterms around the console in the Hall C counting house. The control is via EPICS and includes a graphical display so that the status of each HV channel can be seen at a glance. Operating instructions are in section 2.6.6. Typical high voltages for SOS detector elements are shown in Table 2.21.
As a general rule no work should be done on detectors which are under High Voltage and High Voltage cables should never be removed or installed while the supply is on. General information about the use of the CAEN power supplies can be found earlier in this chapter.