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(gamma,p) Run Plan Draft 1

(gamma,p) Run Plan
1.152 GeV gamma p 

Instructions

  1. Estimated currents result in ~2 kHz DAQ rate. We are most interested in T3 and T5 triggers. Prescale T1, T2, and T4 triggers to ~ 100 Hz; these give us information on efficiencies. If dead time / trigger rates are high, lower currents (not below 1 microA) and / or prescale data. Current may be raised if rates are < 1 kHz.
  2. With current and time suggested, we should get about the number of good events with good FPP scattering suggested - see online replay instructions.
  3. Avoid file splitting if possible. Stop and restart runs when needed.
  4. The time estimate is based on scheduled time with 50% availability. Do not significantly shorten runs if count rate is larger than expected. If count rate is below estimates, run up to about two times longer, unless we are behind schedule.
  5. Radiator-out hydrogen runs should be about 60% as long as radiator-in runs, except all empty target runs should be for 10 minutes of data - do not worry about adjusting their time.
  6. For each angle / momentum setting, take a measurement on 12C solid target for the last ~10 minutes while the magnets are settling. This should be done with raster off. (This is used to check spectrometer offsets, which are not now regularly measured.)
  7. Comment: Pi+ background is kinematically allowed only for thetacm > 90 deg, forward-angle data should be all protons
Task Ie  Target  Radiator  th-e  p-e  th-h  p-h  FPP  Time Counts
(uA)  (%)  deg  GeV  deg  GeV  door  h or m good event+good FPP
120ocm Q2=0.39 ep elastic ~1 H out 34.96 0.941 54.99 0.658 3 4 h ~3 M
120ocm , 70 MeV offset ~1 H out 36.96 0.843 54.99 0.619 3 1.2 h ~4k
" " empty out " " " " " 10 m ?
" " empty in " " " " " 10 m ?
" " H in " " " " " 2 h ~20 k
105ocm 50 MeV offset ~2 H in 46.90 0.784 47.19 0.780 6 2 h ~60 k
" " empty in " " " " " 10 m ?
" " empty out " " " " " 10 m ?
" " H out " " " " " 1.2 h ~10 k
90ocm 40 MeV offset 2 H out 58.37 0.700 39.71 0.933 3+6 50 m ~10 k
" " empty out " " " " " 10 m ?
" " empty in " " " " " 10 m ?
" " H in " " " " " 1.5 h ~60 k
75ocm 30 MeV offset 3 H in 71.64 0.610 32.53 1.077 1.5+3+6 1.5 h ~100 k
" " empty in " " " " " 10 m ?
" " empty out " " " " " 10 m ?
" " H out " " " ' " 55 m ~20 k
60ocm 25 MeV offset ~2 H  out 87.34 0.521 25.65 1.203 1.5+3+9 35 m ~20 k
" " empty out " " " " " 10 m ?
" " empty in " " " " " 10 m ?
" " H in " " " " " 1 h 125 k
45o cm, 25 MeV offset 1 H in 106.0 0.442 19.02 1.304 1.5+6+9 1 h ~180 k
" " empty in " " " " " 10 m ?
" " empty out " " " " " 10 m ?
" " H out " " " " " 35 m ~30 k
1.152 GeV gamma d

Instructions

  1. We are only interested in hadron arm singles triggers, T3 and same T4. Prescale away T1, T2, and T5. Prescale T4 to ~ 100 Hz.
  2. Run deuteron photodisintegration at the largest current that keeps dead time small, < 20 %, but do not run above 30 microA. If you are rate-limited to below ~20 microA, contact Ron Gilman.
  3. With current and time suggested, we should get about the number of good events with good FPP scattering suggested - see online replay instructions.
  4. The time estimate is based on scheduled time with 50% availability. Do not significantly shorten runs if count rate is larger than expected. If count rate is below estimates, run up to about two times longer, unless we are behind schedule.
  5. Do not file split. Stop and restart runs if needed. Also, restart the run at least once every hour.
  6. Take in order
 
Task Ie  Target  Radiator  th-e  p-e  th-h  p-h  FPP  Time Counts
(uA)  (%)  deg  GeV  deg  GeV  door  h or m good event+good FPP
90ocm 70 MeV offset 30 D in - - 61.745 1.1424 3 + 9 12 h ~60 k
spectrometer offset check (raster off!) 5 12C out - - " " " 10 m ~1 k
" 30 D out - - " " " 7 h ~10 k
" " H out - - " " " 1 h ?
" " H in - - " " " 1 h ?