Difference between revisions of "Barrel Calorimeter Expert"

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(Chiller Operation)
(Chiller Operation)
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===Chiller Operation===
 
===Chiller Operation===
  
The chillers should be set to 'manual' mode. To change the 'set' temperature simply use the up/down arrows on the front key pad to the desired temperature. The values are in deg F. Wait for the 'readback' temperature
+
The chillers should be set to 'manual' mode. To change the 'set' temperature, use the up/down arrows on the front key pad to the desired temperature. The values are in deg F. Wait for the 'readback' temperature
 
to settle to the 'set' value, as it may overshoot at first. At startup it may be
 
to settle to the 'set' value, as it may overshoot at first. At startup it may be
 
necessary to pull a switch forward that is accessed through the hole on the side of the chiller closest to the front.
 
necessary to pull a switch forward that is accessed through the hole on the side of the chiller closest to the front.

Revision as of 08:57, 14 January 2015

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

Fig. 1. Graphical interface for setting the voltages on the BCAL. Indicated are the pulldown menus for retrieving saved voltages from a file and the menus for turning the voltages on and off.

Changes to the voltage settings are only allowed by an expert, or under his/her guidance. The bias voltages for the MPPC sensors can be set using the GUI show in Fig. 1. The bias settings must be set separately for upstream and downstream. For upstream, use the "ALL U Bias" button to select the menu and choose "BCAL U: Set Bias Parameters." Set the "ramp up/down"= 5A/s, "Set Voltage Offset" (overbias) to the desired value (nominal=1.2 V), then the "Temperature for Voltage Settings" to the desired value (nominal=18 deg C). A <carriage return> must be entered for the value to register. Once complete, click on the "Set Voltage" button. Wait for the "wait" rainbow to finish turning. If the voltages are already on, you are done, otherwise you need to use the "BCAL U: Turn ON Bias Channels" menu item to turn them on. 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.

Chiller Operation

The chillers should be set to 'manual' mode. To change the 'set' temperature, use the up/down arrows on the front key pad to the desired temperature. The values are in deg F. Wait for the 'readback' temperature to settle to the 'set' value, as it may overshoot at first. At startup it may be necessary to pull a switch forward that is accessed through the hole on the side of the chiller closest to the front.

LED calibration runs

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.

Table: Expert personnel for the BCAL system
Name Extension Date of qualification
Elton Smith 269-7625 May 20, 2014