HRS Checkout (Experts)

The detector checkout is best done using a fairly uniform illumination, which is provided for by 5 μA on the optics target at the following kinematics:

E' = 0.75 GeV, θ = 48.0 degrees (W = 2.38 GeV, Q² = 2.2 GeV²). The HRS electron rates should be about 4.5 Hz.

Ebeam [GeV]	P0 [GeV/c]	θe [deg]	Collimator	Target	Fast Raster X x Y	Beam Current	Trigger
4.481	0.75	48.0	None	Optics	2 x 2 mm2	5 μA	S0&&S2m

1. With the above kinematics, take a run (at least 25K electrons or 80 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.