HRS Checkout (Experts)

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The detector checkout is best done using a fairly uniform illumination, which is provided for by 20 μA on the optics target at the following kinematics:

The Right HRS electron rates should be about 119 Hz, and the left HRS electron rates should be about 9.8 kHz.
Make sure to adjust the prescale factors to obtain a reasonable deadtime < 10%.

HRS Ebeam [GeV] P0 [GeV/c] θe [deg] Collimator Target Fast Raster
X x Y
Beam Current Trigger
Right 2.217 0.85 48.75 None Optics 2 x 2 mm2 20 μA S0&&S2m
Left 2.217 1.0 17.5 None Optics 2 x 2 mm2 20 μA S0&&S2m
  1. With the above kinematics, take a run (at least 200K electrons or 30 minutes) and verify that all detector channels are working.
  2. Using the same run, produce a ROOT tree, and do the following: make a spectrum of x vs. y at the focal plane. What you should see is a "spider" with 5 legs. The non-straightness of the central legs indicates there is an offset in the Z or Y direction. If you don't see a "spider" or something resembling it, then of of the polarities of the HRS magnets is set wrong (or a magnet is off).
  3. Check that the signals are well timed.
  4. Determine correct thresholds.
  5. Verify all scalers are incrementing.
  6. Check for double pulsing and time the wire chamber signals.
  7. Are the scintillator signals on scale in the ADCs?
  8. PID threshold checks.