From Friday 9/25/98 Swing Shift to Monday 10/5/98 Owl Shift
Run Coordinator : Sebastien Incerti
a) data with collimators in : 1.8 M b) data with collimators out : 1.7 M - Elastic data on the polarized Helium 3 target at I = 3 uA - P = 1.670 GeV : 6 M data collected with collimators in.
- Commissioning Data
- Reference cell elastic data on N2 : The beam current was I = 3 uA. Momentum P = 1.700 GeV. The collimators were in and the pressure was changed from 1 atm to 2 atm to study the pressure curve. The total number of events collected reaches 1.8 M. - Reference cell quasielastic data on N2 : The beam current was I = 3 uA. Momentum P = 1.600 GeV. The collimators were in and the pressure was set to 5 atm. The total number of events collected reaches 1.2 M. - Empty reference cell data at I = 3 uA - P = 1.700 GeV :E94010 Run Plan Data - Priority 1 - Rank 1
(GeV) |
(uA) |
(%) |
(%) |
(M = 1E6) |
(M) |
P1 = 1.607 | 3 | 65 | 25 to 28 | 97 | 37 |
P2 = 1.484 | 2 to 3 | 68 | 28 | 27 | 10 |
P3 = 1.369 | 3 | 68 | 30 | 26 | 23 |
P4 = 1.264 | 3 | 68 | 30 | 24 | 16 |
P5 = 1.167 | 3 to 5 | 68 | 30 | 21 | 13 |
P6 = 1.077 | 6 | 68 | 30 | 19 | 10 |
P7 = 0.994 | 6 | 68 | 30 | 16 | 7 |
P8 = 0.918 | 6 to 12 | 68 | 30 | 24 | 8 |
P9 = 0.847 | 13 | 68 | 30 | 24 | 8 |
P10 = 0.782 | 10 to 13 | 68 | 30 | ... /20.8 | ... /6.5 |
Those rates take into account the difference between the 70 % beam polarization assumed in the run plan and its actual value, the difference between the 40 % target polarization assumed in the run plan and its actual value, the efficiencies of the standard electron cuts and the glass target window contribution. - Reference cell filled with N2 : - P = 1.607 GeV - I = 3 uA - Press = 5 atm - Coll. in : 8.4 M data - P = 1.484 GeV - I = 6 uA - Press = 5 atm - Coll. in : 8.1 M data - P = 1.369 GeV - I = 3 to 6 uA - Press = 5 atm - Coll. in : 10.3 M data - Empty reference cell : - P = 1.607 GeV - I = 3 uA - Coll. in. : 3.0 M data - P = 1.607 GeV - I = 3 uA - Coll. out : 6.0 M data - P = 1.484 GeV - I = 8 uA - Coll. in : 2.5 M data - P = 1.484 GeV - I = 4 uA - Coll. out : 5.8 M data - Elastic on polarized Helium 3 : - P = 1.737 GeV - I = 13 uA - Coll. in. : 10 M dataPolarized Beam The polarization of the beam is about 68%. The optimal raster size given by newspot is 4 mm in X and 3.5 mm in YPolarized Target The polarization of the target reaches a plateau at ~30 % and no major polarization loss has been observed when running at high current.Summary of Beam Schedule
9/25/S | 8.0 | - | - | - |
9/26/O | 6.3 | 1.7 | - | - |
9/26/D | 7.0 | 1.0 | - | - |
9/26/S | 1.3 | 6.7 | - | - |
9/27/O | 2.0 | 6.0 | - | - |
9/27/D | 2.0 | 6.0 | - | - |
9/27/S | 0.5 | 1.5 | 6.0 | H VDC - E Cherenkov |
9/28/O | 0.5 | - | 7.5 | DAQ - Moeller |
9/28/D | 2.0 | 4.5 | 1.5 | H VDC - Raster |
9/28/S | 1.3 | 1.7 | 5.0 | He transient in magnets |
9/29/O | - | 8.0 | - | - |
9/29/D | 1.8 | 6.2 | - | - |
9/29/S | 1.0 | 3.7 | 3.3 | H VDC |
9/30/O | - | 7.0 | 1.0 | Magnets tripped - Coda |
9/30/D | 0.7 | 5.0 | 2.3 | H Q1 JT valve |
9/30/S | 1.5 | 4.9 | 1.6 | H Q1 trips - Coda |
10/1/O | - | 7.2 | 0.8 | H Q1 trips - Coda |
10/1/D | 0.3 | 3.5 | 4.2 | H Q1 trips |
10/1/S | 0.3 | 6.5 | 1.2 | Moeller - Current asym. |
10/2/O | - | 4.3 | 3.7 | ERS compressor - E VDC |
10/2/D | - | 5.4 | 2.6 | Magnets (He) |
10/2/S | 2.5 | 5.5 | - | - |
10/3/O | 0.5 | 5.9 | 1.6 | E dipole |
10/3/D | 0.2 | 7.6 | 0.2 | - |
10/3/S | - | 6.3 | 1.7 | - |
10/4/O | - | 6.5 | 1.5 | - |
10/4/D | - | 7.1 | 0.9 | - |
10/4/S | - | 6.5 | 1.5 | - |
10/5/O | 4.8 | - | 3.2 | Coda |
TOTAL : | 44.5 h | 136.2 h | 51.3 h | - |
Ratio : | 19 % | 59 % | 22 % | - |
BNA stands for Beam Not Available BIU stands for Beam In Use BABNIU stands for Beam Available But Not In UseHall A Schedule - Moeller studies : 20 h ( ~ 9 % of total time) - Target NMR : 25 h (~ 11 %) - Target EPR : 2 h (< 1 %) - Target Field Rotation : 6 h (~ 3 %) - Target problems : 7 h (~ 3 %) - DAQ problems : 9 h (~ 4 %) - Magnets problems : 22 h (~ 9 %) - Electron Arm problems (Ch, ...) : 3 h (~ 1 %) - Hadron Arm problems (VDC, Ch, ..) : 13 h (~ 6 %) - Misc (interlocks) : 5 h (~ 2 %)Problems and remaining tasks - Target polarization reaches a plateau at ~30 %. 37 % expected. - Hadron arm : 1) VDC chamber 2) Data show some unknown problems - Small leak in the reference cell (next Maintenance Days). - Fix downstream BCM cavity (idem) - Check Moeller system (idem). - Replace the damaged target heater (idem, but not crucial). - Install crash button to turn the lasers off from the Counting House A (idem). - Check target RTD system (idem) - Improve the beam intensity asymmetry correlated to helicity (.1 % now) - Display / keep track of the EPICS variable UGL1I00DI24_24M giving the status of the half wave plate (in or out) the laser beam (polarized gun) - Install the amperemeter to monitor the current in the small Helmholtz coils - Beam energy measurement wih the e-p device at 2 and 5 pass.Conclusion We have not been able to fullfill the Priority 1 - Rank 1 run plan before the maintenance day. The 2 pass running needs to be extended more after the two maintenance days, starting Monday 10/4, 11 PM.