Difference between revisions of "InsertingTargetProcedure"

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If a lead target has not already been commissioned, this run plan is incomplete.  In this case, please expert documentation on "how to commission a lead target" should be used.  
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If a lead target has not already been commissioned, this run plan is incomplete.  In this case, an expert is needed. They can refer to documentation (to be written) on "how to commission a lead target".  
  
 
For a lead target that is already known and commissioned:  
 
For a lead target that is already known and commissioned:  
 +
# Check if the raster has been measured for the particular beamline quadrupole settings in use now. See "how to check if raster has been measured for these beam optics" (to be written)
 +
#* If the raster size has already been measured, then you can use the previously used raster specification in "MCC units" that correspond to this set of quadrupole setpoints.
 +
#* If the raster size has not been measured for this specific set of quadrupole settings, you must measure the raster size with the 90-degree carbon hole.
 
# Measure the raster size with the 90-degree carbon hole
 
# Measure the raster size with the 90-degree carbon hole
## With no target, establish 5 uA beam. Move beam center to center on [https://logbooks.jlab.org/entry/3695570  carbon hole location]
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## With no target, establish 2uA beam. Turn off FastFeedback.
## turn off beam. Move in C-hole 90deg target.  
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## With no target and 2 uA beam. Move beam to center on the collimator: bpm1H04a (x,y) = (0,0), bpm1H04e (x,y) = (0.6, 0.4)mm. Record the cavbpm4b and cavbpm4d readbacks at this location. (The cavity bpms will continue to work at very low current)
 +
## Move beam to center on the [https://logbooks.jlab.org/entry/3695570  carbon hole location] (Note: after a long down this might not be the accurate center.)  Record the cavbpm4b and cavbpm4d setpoints at this location.
 +
## turn off beam. (do not change correctors, and be sure target lock is turned off, so beam will recover to same location).
 +
## verify that  [[HVgui | VDC and GEM detector HV]] are off
 +
## Move in C-hole 90deg target.  
 
## turn on 20 nanoAmp beam. (At the present time, this corresponds to MCC using an attenuator setting = 107.  If you have doubts, you can always ask MCC to use Faraday Cup#2 to find an attenuator setting for approximately 20 nA.)   
 
## turn on 20 nanoAmp beam. (At the present time, this corresponds to MCC using an attenuator setting = 107.  If you have doubts, you can always ask MCC to use Faraday Cup#2 to find an attenuator setting for approximately 20 nA.)   
 
## Set raster to the "MCC units" listed on the white board.
 
## Set raster to the "MCC units" listed on the white board.
## run spot++. verify that raster (4mm x 6mm in reality) is (approximately) appropriately filled by the 2mm diameter hole.
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## run spot++. verify that raster (4mm x 6mm is desired in reality) is (approximately) appropriately filled by the 2mm diameter hole. If not, tune the MCC setpoints until the raster size scale matches the dimensions for the 2mm diameter hole. (it may not "look" round, but the horizontal and vertical dimensions should both match a 2mm diameter hole).
## remove the C-hole target
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# Prepare beam for Lead target
 
# Prepare beam for Lead target
 +
## remove the C-hole target
 
## establish 1 uA beam (with no target)
 
## establish 1 uA beam (with no target)
 
## move beam to collimator center 4A(x,y) = (0,0) and 4E(x,y) = (0.6, 0.4)mm.  
 
## move beam to collimator center 4A(x,y) = (0,0) and 4E(x,y) = (0.6, 0.4)mm.  
##* If (and only if) the cavities are in low current mode, in the present calibration they will read 4B(x,y) = (2.1,-0.2) and 4C(x,y)=(4.1,0.2), even at very low beam current.
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##* Record the cavbpm4b and cavbpm4d positions.  
 +
## turn beam off
 
## set raster to 10x10 (MCC units)
 
## set raster to 10x10 (MCC units)
## set current to 20 nanoAmps.  (Again, at present, this is an attenuator setting of 107.)
 
## verify that  [[HVgui | VDC and GEM detector HV]] are off
 
 
# Move to lead target
 
# Move to lead target
 +
## verify that  [[HVgui | VDC and GEM detector HV]] are off
 
## mask and insert lead target
 
## mask and insert lead target
## establish 20nanoAmp beam.  
+
## establish 20 nanoAmp beam. (Again, at present, this is an attenuator setting of 107.)
 
## run spot++.  Verify no edges.
 
## run spot++.  Verify no edges.
## Set raster to nominal 6mm (width) x 7.2 mm (height)
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## Set raster to nominal size. (presently 6mm width and 7mm height).
 
## run spot++ (this allows us to check the uniformity of the lead).
 
## run spot++ (this allows us to check the uniformity of the lead).
 
## turn off [[HVgui | S0 voltages]] on left and right arms.  
 
## turn off [[HVgui | S0 voltages]] on left and right arms.  
 
## set to desired current.  No more than 50uA.   
 
## set to desired current.  No more than 50uA.   
 
##* WATCH target temperatures, target return coolant temperature, collimator temperature, and beamline thermocouples.
 
##* WATCH target temperatures, target return coolant temperature, collimator temperature, and beamline thermocouples.

Revision as of 17:05, 6 July 2019

If a lead target has not already been commissioned, this run plan is incomplete. In this case, an expert is needed. They can refer to documentation (to be written) on "how to commission a lead target".

For a lead target that is already known and commissioned:

  1. Check if the raster has been measured for the particular beamline quadrupole settings in use now. See "how to check if raster has been measured for these beam optics" (to be written)
    • If the raster size has already been measured, then you can use the previously used raster specification in "MCC units" that correspond to this set of quadrupole setpoints.
    • If the raster size has not been measured for this specific set of quadrupole settings, you must measure the raster size with the 90-degree carbon hole.
  2. Measure the raster size with the 90-degree carbon hole
    1. With no target, establish 2uA beam. Turn off FastFeedback.
    2. With no target and 2 uA beam. Move beam to center on the collimator: bpm1H04a (x,y) = (0,0), bpm1H04e (x,y) = (0.6, 0.4)mm. Record the cavbpm4b and cavbpm4d readbacks at this location. (The cavity bpms will continue to work at very low current)
    3. Move beam to center on the carbon hole location (Note: after a long down this might not be the accurate center.) Record the cavbpm4b and cavbpm4d setpoints at this location.
    4. turn off beam. (do not change correctors, and be sure target lock is turned off, so beam will recover to same location).
    5. verify that VDC and GEM detector HV are off
    6. Move in C-hole 90deg target.
    7. turn on 20 nanoAmp beam. (At the present time, this corresponds to MCC using an attenuator setting = 107. If you have doubts, you can always ask MCC to use Faraday Cup#2 to find an attenuator setting for approximately 20 nA.)
    8. Set raster to the "MCC units" listed on the white board.
    9. run spot++. verify that raster (4mm x 6mm is desired in reality) is (approximately) appropriately filled by the 2mm diameter hole. If not, tune the MCC setpoints until the raster size scale matches the dimensions for the 2mm diameter hole. (it may not "look" round, but the horizontal and vertical dimensions should both match a 2mm diameter hole).
  3. Prepare beam for Lead target
    1. remove the C-hole target
    2. establish 1 uA beam (with no target)
    3. move beam to collimator center 4A(x,y) = (0,0) and 4E(x,y) = (0.6, 0.4)mm.
      • Record the cavbpm4b and cavbpm4d positions.
    4. turn beam off
    5. set raster to 10x10 (MCC units)
  4. Move to lead target
    1. verify that VDC and GEM detector HV are off
    2. mask and insert lead target
    3. establish 20 nanoAmp beam. (Again, at present, this is an attenuator setting of 107.)
    4. run spot++. Verify no edges.
    5. Set raster to nominal size. (presently 6mm width and 7mm height).
    6. run spot++ (this allows us to check the uniformity of the lead).
    7. turn off S0 voltages on left and right arms.
    8. set to desired current. No more than 50uA.
      • WATCH target temperatures, target return coolant temperature, collimator temperature, and beamline thermocouples.