procedure for target scan

  1. For the nominal intensity (30*10^11), the event rate at the beam center is about 200-500k/s (right now, Yellow vertical target 2 gives about 100k/s instead since it is very thin). If the rate is lower by 100k with this intensity, then a target scan should be done to find the center of the beam. The step size should be 5 to 10 counts. The total movement of beam between injection and store or ramp to ramp is less than 20 counts. So that is the biggest movement one should try on one direction.
  2. Use "test run" button in the Polarimeter/Control pet page to do target scan. While this pet page is open, open another pet page for Target/Blue or Target/Yellow. Change the desired target rotary position. Make sure you are using the right axis (vertical or horizontal) and right target (1,2,3 or Background).
  3. With the 5-10 step sizes find the peak rate and stop the test run and start the regular run or data run.
  4. If no counts were found with 20 counts on each side of movement, the target is likely gone. Call Osamu or Haixin.
Haixin 5/21/03