InsertingTargetProcedure

From PREX Wiki
Revision as of 22:13, 28 June 2019 by Kent Paschke (Talk | contribs)

Jump to: navigation, search

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.

For a lead target that is already known and commissioned:

  1. Measure the raster size with the 90-degree carbon hole
    1. With no target, establish 5 uA beam. Move beam center to center on carbon hole location
    2. turn off beam. Move in C-hole 90deg target.
    3. 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.)
    4. Set raster to the "MCC units" listed on the white board.
    5. run spot++. verify that raster (4mm x 6mm in reality) is (approximately) appropriately filled by the 2mm diameter hole.
    6. remove the C-hole target
  2. Prepare beam for Lead target
    1. establish 1 uA beam (with no target)
    2. 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.
    3. set raster to 10x10 (MCC units)
    4. set current to 20 nanoAmps. (Again, at present, this is an attenuator setting of 107.)
    5. verify that VDC and GEM detector HV are off
  3. Move to lead target
    1. mask and insert lead target
    2. establish 20nanoAmp beam.
    3. run spot++. Verify no edges.
    4. Set raster to nominal 6mm (width) x 7.2 mm (height)
    5. run spot++ (this allows us to check the uniformity of the lead).
    6. turn off S0 voltages on left and right arms.
    7. set to desired current. No more than 50uA.
      • WATCH target temperatures, target return coolant temperature, collimator temperature, and beamline thermocouples.