Electron Detector

Standard Running Procedure

• from any cdaq machine, from the directory ~/compton/ execute StripTool edetectorEpics.stp . This pulls up the strip chart of some relevant epics variables for e-detector. If we are unable to locate this file, the following epics variables should be explicitly opened.
  • 4 Hall-C Chicane BPMs
    • 3P01A (IPM3P01A.XPOS , IPM3PO1A.YPOS)
    • 3P02A (IPM3P02A.XPOS , IPM3PO2A.YPOS)
    • 3P02B (IPM3P02B.XPOS , IPM3PO2B.YPOS)
    • 3P03A (IPM3P03A.XPOS , IPM3PO3A.YPOS)
  • Rates on Scintillator (cComptScintRateNorm) on the Compton laser table, along with Photon detector Rates (cComptPhotonRateNorm)
• Turn on the HV on the e-detector planes. (Current operating voltage: plane-2: -260V, plane-3: -360V, plane-4: -360V)

Request beam to be set through the chicane, with FFB turned ON

• Check Chicane view: on any cdaq machine type edmmonticello, from the Monticello screen
  • open Magnets -> Magnet Commander
    • 3C -> Compton Combo
    • In this Hall C Compton Control screen, the REQUESTED and ACTUAL current readbacks should be ~104 A
  • open BPM -> BPM Overview
    • open Absolute -> on the Hall C column from the left bottom of this screen
    • BPM 3P01A, 3P02A, 3P02B and 3P03A should have finite non-zero read back
• Check compton rates from the photon detector (typically 600 per uA per second)
  • If the Scintillator rates are too high (> 2000 Hz/uA), DO NOT proceed without talking to an expert from photon detector group.
  • The Fast feedback has been observed to give lower background rate, the status of FFB can be checked on the HALL-C general tools screen on the main-monitor of HALL-C

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Backout Procedure

https://hallcweb.jlab.org/polwiki/index.php/E-Detector_Motion_System#Parking_the_detector

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courtesy: Thanks to Dave Gaskell for the motivation to organize this information

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