Difference between revisions of "Commissioning Plan for Left HRS"
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Initially we'll have the HRS at about 80 degrees. We can run with beam and check detectors and look | Initially we'll have the HRS at about 80 degrees. We can run with beam and check detectors and look | ||
at reconstructed angles at the target. We can do this parasitically or late at night when nobody | at reconstructed angles at the target. We can do this parasitically or late at night when nobody | ||
| − | is in the hall. (We need the beam on target.) | + | is in the hall. (We need the beam on target.) For the reconstructed angles, all is well if the |
| − | acceptance looks about right (a familiar rectangle) and | + | acceptance looks about right (a familiar rectangle) and if the comparison of TRANSPORT angles to |
| − | we remove Bigbite, we can put in the sieve slits and check more carefully the optics. If the optics | + | Monte Carlo looks good. Later, when we remove Bigbite, we can move the HRS to smaller angles (~30 degrees) |
| − | are really bad (blurry hole pattern) we can do an optics calibration run plan. However, I doubt that | + | and put in the sieve slits and check more carefully the optics if time permits. If the optics are |
| − | + | really bad (blurry hole pattern) we can do an optics calibration run plan. However, I doubt that | |
| + | we even need an Optics calibration. | ||
<pre> | <pre> | ||
Revision as of 12:57, 8 June 2021
Before we use the Left HRS to commission HCAL, we need to spend some time checking the HRS itself. Most checks of detector and the DAQ can be done with cosmics or with pulsers, but the two topics where we need beam are: 1) Check the HV on the Cherenkov detectors -- need electrons going in the right direction, and 2) Check the magnetic optics. We can start with an optics database from the Tritium era.
Initially we'll have the HRS at about 80 degrees. We can run with beam and check detectors and look at reconstructed angles at the target. We can do this parasitically or late at night when nobody is in the hall. (We need the beam on target.) For the reconstructed angles, all is well if the acceptance looks about right (a familiar rectangle) and if the comparison of TRANSPORT angles to Monte Carlo looks good. Later, when we remove Bigbite, we can move the HRS to smaller angles (~30 degrees) and put in the sieve slits and check more carefully the optics if time permits. If the optics are really bad (blurry hole pattern) we can do an optics calibration run plan. However, I doubt that we even need an Optics calibration.
Rate calculations for e-P elastic scattering. Assuming 15 cm LH2 target. 1 uA of beam. Here I used some of the kinematics given in the HCAL run plan. 4.4 GeV is not very practical. Note, the sieve slit will cut the rate by a factor of 200. E' is the momentum setting of the L-HRS for elastic. E theta_HRS E' Rate (GeV) (degrees) (GeV) (Hz for 1 uA beam) 4.4 30.9 2.64 2.9 Hz/uA 4.4 34.1 2.44 1.3 Hz/uA 4.4 61.1 1.29 0.018 Hz/uA 4.4 64.3 1.20 0.014 Hz/uA 4.4 67.5 1.13 0.010 Hz/uA 4.4 70.7 1.06 0.008 Hz/uA 2.2 30.9 1.65 216 Hz/uA ..... angle available when Bigbite removed (can run with sieve) 2.2 34.1 1.57 100 Hz/uA 2.2 40 1.42 29 Hz/uA 2.2 45 1.30 11.7 Hz/uA 2.2 80 0.75 0.27 Hz/uA .... run here at 40 uA (without sieve) 2.2 90 0.66 0.15 Hz/uA
