Bull's Eye Scan

From HallCWiki
Jump to: navigation, search

Bull's Eye Scan: BPM vs Harp scan Calibration

 We want to be able to correlate the BPM ADC data with the "absolute"
 positions given by the surveyed Harp scanners for these nominal BPM
  (0, 0), (+2,+2), (+2,-2), (-2,+2), (-2,-2)

NOTE: The positions above can be experiment specific. Confirm with RC.


Starting Settings
 Beam:           5uA CW,  Raster OFF
 Beam Position:  (0, 0)
 Target:         Carbon or 'No Target'
 Have a stripchart of the 3HO4A, 3HO4B, and 3HO4C BPMs visible.  [Run go_beam_stripchart, if needed.]

Start an HCLOG entry titled 'BPM calibration' and record the following for each of the 5 (x, y) points above

  • Requested Beam Position
  • HMS/SHMS Run numbers
  • Harp Scan log entries

For each of the 5 points identified above, do the following

  • We want all BPMs to have (roughly) the same values for each point (so the beam is roughly parallel to the beamline). Tolerances of +-0.3 or so on the requested numbers are fine.
  • Be sure the BPMs and beam are stable, start a CODA in each arm for a few minutes, then call MCC and request that they run and log a harp scan for both 3H07A and 3H07B to the HCLOG.

Just leave the CODA run going during the scans.

Submit your HCLOG summary table

  • Make sure your table is complete
  • Add a screen snapshot of the BPM stripchart