From PREX Wiki
Revision as of 23:07, 28 June 2019 by Kent Paschke
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:
- Measure the raster size with the 90-degree carbon hole
- With no target, establish 5 uA beam. Move beam center to center on carbon hole location
- turn off beam. 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.)
- 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.
- remove the C-hole target
- Prepare beam for Lead 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.
- 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.
- set raster to 10x10 (MCC units)
- set current to 20 nanoAmps. (Again, at present, this is an attenuator setting of 107.)
- verify that VDC and GEM detector HV are off
- Move to lead target
- mask and insert lead target
- establish 20nanoAmp beam. (At present, this is asking attenuator to use attenuator = 107.)
- run spot++. Verify no edges.
- Set raster to nominal 6mm (width) x 7.2 mm (height)
- run spot++ (uniformity check)
- turn off S0 voltages on left and right arms.
- set to desired current. No more than 50uA.
- WATCH target temperatures, target return coolant temperature, collimator temperature, and beamline thermocouples.