Setup of a Drift Tube Muon Tracker and Calibration of Muon ...

Figure 3.6: Display of the slow control software. In the main menu, one can choosethe kind of control board to be addressed (OSUB or OTB). The following sub menusallow to set thresholds, delays, etc. The slow control software is text based, so that itcan be easily controlled via non graphical terminals.signal in this case) and the delay ∆ of the trigger signal can be modified. Alsorandom trigger test pulses can be generated which are used to test the noise behaviorof the detector. A detailed description of the OTB can be found in [61].For the CAN bus communication a PEAK PCAN-USB CAN to USB interfacehas been used. A Linux kernel module was provided by the manufacturer. Onceit is loaded and the adapter is connected via USB, it can be addressed from thecontroller PC as /dev/pcan32 by simply sending text messages to the device [62].Test Pulses To test the functionality of the preamp electronics as well as the dataacquisition, test pulses can be sent from the OSUB boards. A test pulse for a certaintube mimics a hit. Test pulses can either be sent to a single tube or to all odd oreven channels of one OSUB board. The test pulse itself serves as a start signal; astop signal is also generated by the OSUB and distributed to all TDCs via the backplane of the crate.3.2.6 High VoltageThe HV is provided by a CAEN SY127 Power Supply. It is equipped with a 6 kV,1mA positive HV module containing four channels. Each HV channel is connectedto four layers of drift tubes, always one layer per module. This way it is ensured thatthree layers per module remain active if one HV channel trips. The cosmic muontracker is operated with a voltage of 2350 V. The Power Supply can be controlled28