Saclay Drift Chambers - Operating instructions
Contents
1. e Set the ethane fraction to 10 in PLC3 See PLC3 instructions on next page Set the CF fraction to 10 for muon beam 0 for hadron beam g Changing 4 times a doublet volume 2 detectors connected in series takes 2 day Note High Voltage must be turned ON only after the gas mixture is close to nominal 3 Purging flammable gas and shut down of MMs a Set High Voltage OFF Slow Control commands are in the Saclay barrack or in the COMPASS control room b Set the ethane fraction to 0 in PLC3 See PLC3 instructions on next page c Set the CF4 fraction to 0 in PLC3 See PLC3 instructions on next page d Close the MM DC ethane valve in flammable gas arrival rack if DCs detectors have also been prepared for this operation e Purge completely all MM doublets with Neon or Argon Changing 4 times a doublet volume 2 detectors connected in series takes 2 days 4 Operation a b MMs gas flows and mixtures are controlled by PLC3 and by the flow meters in the MM DC gas rack MMs High Voltage and threshold settings are controlled by the COMPASS slow control For Slow Control commands go in the Saclay barrack Check the 6 MM bubblers twice per shift Normal bubbling is in the range 0 3 0 6 Hz 5 PLC3 operation meao op On the touch screen select MM Push the MENU button Push the R4 box in order to enter the password Type the password 6535 and then push ENTER Push the ESC button Select the R1 button2. Ethane proportion This proportion is either 0 no flammable gas or 10 during data taking Change the CF4 proportion if needed
3. 16 June 2008 Micromegas detectors Operating instructions 1 General There are 12 Micromegas detectors assembled in 3 stations MMO1 to MMO3 of 4 planes each V U X Y from upstream to downstream All detectors are identical The active area is 40x40 cm and the gas volume 6 liters per detector Detectors are assembled in doublets back to back with one gas line per doublet The gas mixture is Ne 10 C2H with voltages 380 840 V on the mesh drift electrodes when running with a hadron beam The gas mixture is Ne 10 C2H 10 CF with voltages 400 870 V on the mesh drift electrodes when running with a muon beam The gas flow about 1 liter per doublet and gas mixture is set via the touch screen of the PLC3 located in the COMPASS gas area password required to change percentages 6535 The High Voltages are set using the Saclay Slow Control software Saclay barrack on top of the Gas Area Phones Saclay on call 16 0731 A Magnon 163943 2 Start up of MMs operational gas flow a Make sure that all gas pipes are connected This should be the default situation during both beam time and winter shutdown b Purge detectors with Argon 2days c Perform leak test for all 3 detectors using Argon gas only The leak test has to be made at least once per year before the run d Open the MM DC ethane valve in flammable gas arrival rack Check whether the DCs detectors are also ready they share the same valve
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