Difference between revisions of "Electron Detector"

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== Standard Running Procedure ==
 
== Standard Running Procedure ==
 
=== with the previous beam activity ongoing (parasitically) ===
 
=== with the previous beam activity ongoing (parasitically) ===
* Turn ON High Voltages to the e-detector
+
* take a quick CODA run to check DAQ functionality
** take a quick run to check DAQ functionality
+
* check analyzer functionality
** check analyzer functionality
+
* 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 you are unable to locate this file, the following epics variables should be explicitly opened.  
* from any cdaq machine, from the directory ~/compton open the strip chart by '''StripTool  edetectorEpics.stp''' . This pulls up the strip chart of some relevant epics variables for e-detector. If you are unable to locate this file, the following epics variables should be explicitly opened.  
 
 
** 4 Hall-C Chicane BPMs
 
** 4 Hall-C Chicane BPMs
 
*** 3P01A (IPM3P01A.XPOS , IPM3PO1A.YPOS)
 
*** 3P01A (IPM3P01A.XPOS , IPM3PO1A.YPOS)
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** Take a few long runs with 2/3 and 3/3 trigger at 1.5 cm from the beam, with and without beam, with and without laser
 
** Take a few long runs with 2/3 and 3/3 trigger at 1.5 cm from the beam, with and without beam, with and without laser
 
==== Upcoming ====
 
==== Upcoming ====
Seek a beam time of ~ 5hrs. Following is what is intended:
+
Seek a beam time of ~ 5hrs. Following tasks to be accomplished:
 
+
* With laser turned off for this entire running period resolve the plane-4 HV ambiguity:  (~ 0.5 hrs)
* Resolve the plane-4 HV ambiguity:  (~ 0.5 hrs)
+
**look at output from all 3 planes on the scope, triggering on 2-plane coin while turning on HV of only one plane at a time
**look at output from all 3 planes on the scope, turning on HV of only one plane at a time
+
***do this for plane-2 and plane-3 first
***do this for p2 and p3 first
 
 
***finally turn on p4  (repeat for a few neighboring strips if needed)
 
***finally turn on p4  (repeat for a few neighboring strips if needed)
***record scope shots including coincidences.
+
***record scope shots triggered on coincidences
  
 
* with the DAQ, try to observe a shift in the strip pattern as the detector is lowered towards the beam. (~ 3.5 hrs)
 
* with the DAQ, try to observe a shift in the strip pattern as the detector is lowered towards the beam. (~ 3.5 hrs)
**use 3 active planes if HV ambiguity is resolved, use 3-plane trigger if possible
+
**If the plane-4 ambiguity is resolved then use all 3 active planes for trigger decision
**use smaller min. width rejection if needed.
+
**If plane-4 is not resolved, turn off the HV input to "plane-1" as well as "plane-4", mask the plane-4 signals and use 2-plane triggers only with plane-2 & plane-3.
**unmask the strips neighboring the closest active strip
+
**take quick runs to check if smaller or higher cut on minimum width helps
**take 30 min runs with 5 uA and 3 uA beam with the detector at a reasonably close position (say 1.6 cm from beam)
+
**try to find a trade-off between unmasking the strips neighboring the closest active strip and noise rates
 +
**take 30 min runs with 5 uA, 3 uA and 1 uA beam with the detector at a reasonably close position (say 1.6 cm from beam)
 
**Repeat in steps of 1 mm as the detector is moved closer to the beam (~ 3 steps should be sufficient)
 
**Repeat in steps of 1 mm as the detector is moved closer to the beam (~ 3 steps should be sufficient)
**a 30 min no beam run when the detector is at its closest proximity to beam.
 
  
 
* HV scan for plane 2 only (~1 hr)
 
* HV scan for plane 2 only (~1 hr)
**With the detector at the closest position, and a 3 uA beam scan the HV from 350 - 700V in steps of 50 V taking short 5-10 min runs at each voltage
+
**With the detector at the closest position, and a 3 uA beam scan the HV from 300 - 700V in steps of 100 V taking 10 min runs at each voltage
 +
***use 2 plane trigger, taking background run for each of the applied HV (
 +
***use a single plane trigger, taking background run for each of the applied HV.
 +
**** It might be useful to increase the cut on minimum width in order to get over the excessive noise in the single-plane trigger.
  
  

Revision as of 18:57, 19 November 2010

Standard Running Procedure

with the previous beam activity ongoing (parasitically)

  • take a quick CODA run to check DAQ functionality
  • check analyzer functionality
  • 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 you 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)
    • Normalized Compton Photon Rates (cComptPhotonRateNorm)

Request beam to be set through the chicane and verify the same

  • 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)

Request beam to be taken off, for lowering the e-detector

  • Lower the e-detector to a position in accordance with current run plan
    • Motion mechanism [[1]]
      • begin with the program Go Home
      • jog to the intended position

Run Plan

Previous (Nov 17)

  • Form an external coincidence between strip #5 or 6 of all three planes.
    • count it on a visual scaler. look at each of the 3 plane signals on a scope to determine a good coincidence window.[this setup is ready]
    • record 1/3, 2/3 and 3/3 at 2.8, 2.0 and 1.2 cm from the beam, with and without beam. Collecting statistics for ~ 3-5 minutes
  • Repeat above with the full DAQ. Again 1/3, 2/3 and 3/3 at same distances from the beam, with and without beam.
    • Try a couple of different trigger coincidence widths in the 100 - 250 ns range.
    • Take a few long runs with 2/3 and 3/3 trigger at 1.5 cm from the beam, with and without beam, with and without laser

Upcoming

Seek a beam time of ~ 5hrs. Following tasks to be accomplished:

  • With laser turned off for this entire running period resolve the plane-4 HV ambiguity: (~ 0.5 hrs)
    • look at output from all 3 planes on the scope, triggering on 2-plane coin while turning on HV of only one plane at a time
      • do this for plane-2 and plane-3 first
      • finally turn on p4 (repeat for a few neighboring strips if needed)
      • record scope shots triggered on coincidences
  • with the DAQ, try to observe a shift in the strip pattern as the detector is lowered towards the beam. (~ 3.5 hrs)
    • If the plane-4 ambiguity is resolved then use all 3 active planes for trigger decision
    • If plane-4 is not resolved, turn off the HV input to "plane-1" as well as "plane-4", mask the plane-4 signals and use 2-plane triggers only with plane-2 & plane-3.
    • take quick runs to check if smaller or higher cut on minimum width helps
    • try to find a trade-off between unmasking the strips neighboring the closest active strip and noise rates
    • take 30 min runs with 5 uA, 3 uA and 1 uA beam with the detector at a reasonably close position (say 1.6 cm from beam)
    • Repeat in steps of 1 mm as the detector is moved closer to the beam (~ 3 steps should be sufficient)
  • HV scan for plane 2 only (~1 hr)
    • With the detector at the closest position, and a 3 uA beam scan the HV from 300 - 700V in steps of 100 V taking 10 min runs at each voltage
      • use 2 plane trigger, taking background run for each of the applied HV (
      • use a single plane trigger, taking background run for each of the applied HV.
        • It might be useful to increase the cut on minimum width in order to get over the excessive noise in the single-plane trigger.


Backout Procedure

  1. Turn OFF HV
  2. Retract the detector to position defined as Go Home
  3. Retract further to position defined as Garage
  4. make hclog entry to inform completion of the intended studies, with any quick conclusion which are obvious



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

Request beam according to the intended run plan

Diamond strip electron detector

Test Box

Shielded Flex Cables

Q-Weak Amplifier Discriminator

Low Voltage Power supply for QWAD

e-Detector Motion System

e-Detector Assembly