Difference between revisions of "Barrel Calorimeter Expert"

Revision as of 17:18, 17 November 2014

The Barrel Calorimeter

The barrel calorimeter (BCAL) is a lead-scintillating fiber matrix readout with 3840 S12045 Hamamatsu multi-pixel photon counters (MPPCs). The MPPC light sensors operate a bias voltage less than 76 V. Liquid coolant is circulated through the readout assemblies to set and maintain the temperature of the sensors at their operating temperature between 5 and 25 degrees C.

Routine operation

Instructions for shift personnel are available in the Barrel Calorimeter instructions for shift personnel.

Voltage Setting for Specific Overvoltage and Temperature

The low voltage (LV) and bias voltages for the MPPC sensors can be set using the GUI show in Fig. 2. The voltages for normal operation are recorded in files, which can be restored using the button in the top middle of the screen. The LV and bias settings must be restored separately. Once the voltages have been restored to the memory of the voltage supplies, the user may turn the voltages on by using the "All U Bias" and "All U LV" left buttons in the middle of the BCAL sketch. The voltages for the downstream side are controlled using the buttons on the right. The voltage read back and the current draw of each channel are histogramed and plotted at the bottom of the GUI. When all voltages are on at their set values, the display turns green. Changes to the voltage settings are only allowed by an expert, or under his/her guidance.

Expert personnel

The individuals responsible for checking that the BCAL is ready to take data and setting its operating parameters are shown in following table. Problems with normal operation of the BCAL should be referred to those individuals and any changes to their settings must be approved by them. Additional experts may be trained by the system owner and their name and date added to this table.