Wiki run plan
From Hall A Wiki
Transversity run plan
(updated 10/25/2008, Xiaodong Jiang.) (Section 1, 2, 3. pretty much the same as the version on 10/23/08. Section 4-11 have many changes).
Questions and considerations to be added:
0. Limit the use of un-rastered beam to lower beam power ( < 5 uA )
1. Servey HRS_L during Dec.-Jan. down time.
2. Compass, target servey during Jan. down. Water calibration during Jan. down.
3. No other significant changes during the experiment, and Dec.-Jan. down time. Especially on DAQ, detectors.
4. Reduce the number of reference cell He3 purges, to save operation cost. 5. Decision need to be made by Oct 20th by the target expert if we can run BigBite current to 710 A. If needed, we can run at 690 A or lower to reduce fringe field effet at the target (JP + Yi).
6. Need to fill in rate estimates and total running time for H(e,e'p), He3(e,e') elastic and Delta production etc. Fill in expected physics asymmetries and raw asymmetries.
7. Need to set current limit on pol. He3 cell 15 uA JP (?), reference cell run up to 150 psi (JP ?).
8. Need to calculate the optimized beam-time distribution for reference cell runs.
9. Daily experiment operation meeting, starts 4:00pm counting house upstairs, owl shift leader call in,
i. Major problems during the last three shifts. ii. completed part of the run plan, did we miss anything ? iii. run plan of the next day. Next major changes.
10. Analysis meeting (daily during commissioning, as frequent as needed during production),
starts ~4:30 pm counting house upstairs.
i. status of online software, new variable to add, major changes. ii. on going calibration. New tasks of data analysis. iii. data quality control. Update the online standard histograms. iv. farm cooking. v. expert-shifts for data quality control.
11. Keep "target spin-signal" on at the start of commissioning, for scaler checks.
Solid target and reference cell runs keep target spin signal on.
12. If five-pass beam energy ends up lower than 5.9 GeV, H(e,e'p) calibration kinematics need to be adjusted.
Make sure HRS_L can reach 60 degree.
13. Pay attention to acceptance and detector efficiency etc. hopefully to get cross section to 8% at the end.
Collimator locations.
THE RUN PLAN,
1. Beam delivery checkout with one-pass beam, initial checks.
Start up conditions:
Beam energy lock: ON Hall A.
Beam raster: OFF.
Target: empty or BeO as needed.
Beam entrance and exit window cover OUT.
HRS_L at 16 degree, negative mode, quards cycled, P_HRS=-1.174 GeV/c
Front sieve slit piece and mounting-plate:OUT.
BigBite at 30 degree, 1.5 m drift (target to front surface of BigBite magnet),
710 A current, NEGATIVE polarity. Front sieve slit: OUT completely.
1.1 Beam tuned straight, not through Compton magnets.
1.2 !!!Dropped OUT, X. Jiang 10/22/08!!! Compton detector initial check.
1.3 Harp scan, require that beam sigma_x: 100~200 micron, sigma_y:100~200 micron on two hall A harps.
1.4 Check signals from lumi-monitors, beam position monitors, beam charge monitors.
1.5 Happex beam charge feedback check. !!! A separate commissioning plan and procedures here.!!!
1.6 Center beam on the BeO target's cross mark. Record BPM A and B readings in (x, y).
1.7 Verify settings of target Ion chamber trip limit (MCC with Radcon).
1.8 Beam goes straight to the viewer at the beam dump.
1.9 Does BigBite magnet stearing the beam ?
Turn BigBite magnet ON/OFF, let MCC watch the beam dump screen, make logbook entry.
1.10 When Arun is back from DNP, and after make sure that Hall A beam charge monitors work,
Perform a beam charge calibration, in two steps, need to coordinate with other halls:
i, MCC calibrate injector beam charge monitor against Faradi cup at injector.
ii, Hall A calibrate beam charge monitor against the injector BCM.
Run beam in steps, up to 50 uA !!!, make sure it is RASTERED beam, 2mm by 2mm.
Take CODA data at the same time.
1.11 Lumi detector commisioning plan (Dustin McNulty, 10/23/2008).
--Take data under the various run conditions/luminosities proposed for the
experiment (few hours). This means we need beam on polarized target.
--Analyze the data (online and offline)--determine and catalog optimal HV
and ADC gain settings for each target/beam current combination.
--Repeat measurements to verify proper settings.
--Iterate above two steps if necessary until settings are proper.
--Could/Should also coordinate lumi commissioning tests with target spin-flip tests.
2. One pass polarized beam, E0=1.23264 GeV, HRS single arm runs for target alignment and detector shakedown.
HRS_L@16 degree, negative polarity, quasi-elastic kinematics,
P_HRS=-1.174 GeV/c, for C12 quasi-elastic kinematics.
Front sieve slit plate:OUT.
2.1 HRS_L single arm DAQ check and detector shakedown.
Target: carbon single foil. Beam current: < 5 uA, keep it low. Beam raster: ON, 2mm by 2mm
DAQ: take HRS_L singles trigger.
If BigBite is ready, can also take BigBite singles at the same time.
check out beam position at target with spot++.
check out detectors: VDCs, S1, A1, RICH, short gas Cherenkov, S2M and Leadglass blocks.
check out beam related information in data stream for: BPMs, BCMs, beam RF timing, beam helicity.
check out scalers. Target spin signal, even if polarized target is not ready.
check target OTR if MCC confirms that it is working (need confirm with Arne Freyberger, ext-6268)
Offline analysis: beam helicity scalers make sense ?
Beam position decoding, spot++ parameters set right according to servey ?
Spot++ beam location agrees with MCC's beam spot display ?
Can we clearly see the target foil in y_tar, and in reconstructed z_tar ?
Resolution better than 2cm in z_tar (FWHM) ?
2.2 Target alignment check using carbon hole target. And beam bullseye scan.
Target: carbon hole target.
Beam current: < 5 uA. Beam raster: ON
DAQ: take HRS_L singles. BigBite magnet: ON, negative polarity, I=710 A.
Change raster size, from 2mm*2mm to 4mm*4mm, take runs with HRS_L singles,
use spot++ to tell if beam hits the carbon hole. The hole size is 1mm in diameter.
The hole might be too small (?).
Move beam around to center on the carbon hole
(through a grid of BPMA and BPMB, in parrellel lines so that the beam angle is small).
Establish this point as the nominal beam center position. Put spot++ plot in logbook.
Then do a beam bullseye scan, take separated HRS_L single arm run for each beam position:
this is for beam position calibration.
i. One run at the nominal beam center as established already.
ii. One run at (x,y) of both BPM A and B at (+3.0, +3.0).
(if it takes more than 5-10 minutes for MCC to set it up, settle with (+2.5, +2.5) or lower values)
iii. One run at (x,y) of both BPM A and B at (+3.0, -3.0).
iv. One run at (x,y) of both BPM A and B at (-3.0, -3.0).
v. One run at (x,y) of both BPM A and B at (-3.0, +3.0).
2.3 Target cell alignment check using polarized He3 cell.
Target: polarized He3. Beam current: < 5 uA. Beam raster: ON
DAQ: take HRS_L singles.
BigBite magnet: ON, NEGATIVE polarity, I=710 A.
Take runs with HRS_L, record BigBite singles rates, wire chamber rates.
Change raster size until rates have a dramatic change, that's when the beam hitting the cell wall.
If needed, move beam around with the same amount on BPMA and BPMB (through a grid in locations)
Reduce raster size, to settle around 2mm*2mm.
2.4 If beam can not go through the dump straight, check beam steering by turning BigBite
magnet ON/OFF in 200 A steps. Coordinate with target expert on turning the target correction coils
ON/OFF.
2.5 Ask Eugene Chudakov to check if beam is acceptable for a Moller measurement.
Ask MCC to record the beam tune setting, inlcuding the raster setting and the Moller quards settings.
Make a Moller measurement when we are satisfied with beam delivery,
and after we have a working polarized He3 target (Eugene Chudakov).
2.6 A run with a large beam charge asymmetry, with HRS_L+BigBite coda, Moller taking runs at the same time.
To verify the signs of beam helicity signal between different systems are consistent.
(Eugene Chudakov and Bob Michaels).
2.7 Beam charge calibration (Arun Saha).
!!! Turn BigBite wire chamber and pre-shower+shower HV OFF !!!
Carbon single foil target, beam current 1 uA to 50 uA, raster ON.
!!! Remember to take HRS_L singles runs while we're doing beam charge calibration. !!!
Check Lumi data to see if counts scale with beam current.
Offline analysis: update BCM convertion factors.
Plot Lumi counts vs beam currents.
Injector's BCM reading in EPICS data stream ?
3. One pass polarized beam, E0=1.23264 GeV, HRS single arm runs with the polarized He3 target.
If BigBite is ready, we can take some BigBite singles trigger at the same time.
If the polarized target is not ready yet, move to step-4.
HRS_L at16 degree, negative mode, He3 \Delta-production kinematicsfirst, P_HRS=-0.850 GeV/c
HRS_L front sieve slit and holding plate: OUT.
Hopefully BigBite is ready by this time. Take BigBite single arm trigger at the same time.
BigBite current 710 A, NEGATIVE polarity. BigBite sieve slit: OUT.
3.1 Carbon single foil run, 5 uA, raster ON/OFF, 5 min each.
3.2 Carbon multi-foil run, 5 uA, raster ON/OFF, 5 min each. 3.3 Pol. He3 target, transverse in-plane polarization, trans. asy. measurement.
Raster: ON. Beam current: 10 uA (xxx ask JP again xxx)
Total number of HRS_L trigger taken: xxx.xx
!!! Arrange a beam half-wave plate IN/OUT change half way through these runs. !!!
3.4 !!! Tests of target spin flip while in step 3.3. !!!
Offline analysis: do we see a clear double-spin asymmetry A_LT ? does it change sign when target
spin flips, beam half-wave plate IN/OUT.
3.5 Set to He3 elastic kinematics, cycle HRS_L quards, P_HRS=-1.21493 GeV/c (including energy loss),
HRS_L at 16 degree. HRS_L front sieve slit and holding plate: OUT.
!!! Arrange a beam half-wave plate IN/OUT change half way through these runs. !!!
3.5.1. Rotate target to Long., Pol. for He3 elastic Asymmetry calibration.
Target spin flip: OFF, but target spin-signal ON.
3.5.2 He3 cell run. Raster:ON, Beam current: < 15 uA (?).
Total number of HRS_L trigger taken: xxx.xx
Arrange a change of beam half wave plate IN/OUT.
Offline analysis: do we see a double spin asymmetry A_LL ?
Does it change sign with beam half-wave plate IN/OUT ?
Monte Carlo: what is the expect raw He3 elastic asymmetry ?
3.5.3 Reference cell run, He3 pressure curve. Run He3 gas pressure 20~150 psi.
Purge reference cell first.
Raster:ON. Beam current: 15 uA. 5 min each run. 5 steps total.
Offline analysis: single-arm yields and scalers scale ?
Lumi readings scale with He3 pressure ?
3.5.4 Reference cell N2 runs, gas pressure, 20~150 psi.
Purge reference cell first.
Raster:ON. Beam current: 15 uA. 5 min each run. 5 steps total.
Offline analysis: single-arm yields and scalers scale ?
Lumi readings scale with N2 pressure ?
3.6 At the end, set HRS_L back to C12 quasi-elastic kinematics, P_HRS=-1.174 GeV/c.
Don't have to cycle the quards if we are coming down in momentum setting.
3.6.1 Carbon single foil run, raster OFF, beam current 5 uA. 5 min.
3.6.2 Carbon multi-foil run, raster OFF, beam current 5 uA. 5 min.
These runs will be used in confirming spectrometer's pointing.
3.7 Take an access to insert HRS_L front sieve slit.
4. One pass polarized beam, E0=1.23264 GeV, HRS_L single arm optics runs with Sieve Slit.
Carbon elastic with sieve slit IN first, then OUT.
DAQ: take HRS_L singles. If BigBite is ready, can also take some BigBite singles for detector shakedown.
Watch out for deadtime, should be < 20%.
HRS_L@16 degree, negative mode, quasi-elastic kinematics,
P_HRS=-1.2264 GeV/c for C12 elastic kinematics, delta=0% (energy loss included). and
P_HRS=-1.1740 GeV/c for C12 quasi-elastic kinematics.
Front sieve slit insert:IN.
At C12 elastic kinematics:
4.1 Carbon single foil target run, raster ON/OFF, beam current 5 uA. 5 min each
For pionting check and BPM/raster decoding check.
Quick analysis: does the peak show up close to delta=~0% for the single foil run ?
If not, recalculate the HRS momentum settings for delta scan below.
4.2 Carbon multi-foil target run, raster OFF, beam current 5 uA. 10 min each.
Offline analysis: while cutting on c12-elastic peak, do we see clear sieve slit patterens
corresponding to each carbon foil ?
delta-scan for carbon elastic peak,
i, cycle quards,
ii, delta=+3.5%, set P_HRS=1.2693 GeV/c. One run, 5 uA beam, 10 min, or 1.0 million trigger.
iii, delta=+2.0%, set P_HRS=1.2509 GeV/c. One run, 5 uA beam, 10 min, or 1.0 million trigger.
iv, delta=0.0%, set P_HRS=1.2264 GeV/c. One run, 5 uA beam, 10 min, or 1.0 million trigger.
v, delta=-2.0%, set P_HRS=1.2019 GeV/c. One run, 5 uA beam, 10 min, or 1.0 million trigger.
vi, delta=-3.5%, set P_HRS=1.1835 GeV/c. One run, 5 uA beam, 10 min, or 1.0 million trigger.
4.3 Change to C12 qausi-elastic kinematics
Don't need to cycle quards.
4.4 Carbon multi-foil target run, raster ON/OFF, beam current 5 uA. 10 min each.
Offline analysis: do we still see a clear sieve pattern ? It's OK if we don't.
4.5 Carbon single foil target run, raster ON/OFF, beam current 5 uA. 5 min each.
Offline analysis: centrual foil should show up at the same location.
4.6 Take an access to take out HRS_L front sieve slit AND the supporting plate.
While we are taking the access, cycle HRS_L quards, set magnet back to C12 elastic kinematics.
Again, at C12 elastic kinematics delta=0.0%, P_HRS=1.2264 GeV/c
4.7 Carbon multi-foil target run, raster OFF, beam current 5 uA. 10 min each, take two runs.
Offline analysis: we should be able to understand cross sections from every foil.
4.8 Change HRS_L to C12 qausi-elastic kinematics.
Don't need to cycle the quards.
4.9 Carbon multi-foil target run, raster OFF, beam current 5 uA. 10 min each, take two runs.
Offline analysis: we should be able to understand the change of acceptance along z_tar.
Compare with HRS_L Monte Carlo for acceptance change along z_tar.
4.10 After these activities, we are ready to move HRS_L to 58.1 degree when we have a chance,
and when the BigBite is ready. !!! Follow the Operation Safety Procedures !!!
5. BigBite single-arm runs, detector and DAQ checkout. One pass polarized beam, E0=1.23264 GeV.
At the same time of HRS single-arm runs, BigBite at 30 degree, 710A magnet current, NEGATIVE polarity.
BigBite sieve slit: OUT.
5.1 Detector shakedowns, carbon single foil or multi-foil targets, 5 uA beam.
Check wire-chambers, gas Cherenkov, preshower+shower, scintillators.
5.2 When the beam is stable enough, and all wire-chamber shakedown is completed.
Wire-chamber HV scan, and PreAmp threshold voltage scan (!!! run plan by Xin Qian here !!!).
5.3 Check beam helicity sorted BigBite scalers, synk-check of HRS and BigBite scalers.
5.4 Check target spin gated BigBite scalers.
5.5 Check Lumi-monitors. "Seudo-Synk" check of Lumi and BigBite scalers.
Offline analysis: does lumi information line up in time with BigBite event ?
5.6 BigBite trigger threshold check (!!! run plan by kalyan here !!!).
5.7 Verify DAQ dead time calculaion from scalers.
5.8 Beam current vs wire chamber dark current scan.
5.9 Check start-of-run and end-of-run CODA log entry.
6. BigBite single arm runs, optics study. One pass beam, E0=1.23264 GeV, polarized. BigBite at 30 degree, 710 A current NEGATIVE polarity. BigBite sieve slit: OUT, to start with.
6.1 Carbon single foil run, < 5 uA beam, raster: OFF/ON one run each, 5 min.
6.2 Carbon multi-foil run, < 5 uA beam raster: OFF/ON one run each, 5 min.
6.3 Change target to reference cell, fill with H2 gas 150 psi.
Raster: ON, 2mm by 2 mm, beam current: 5-10 uA. Take one run H(e,e'), 5 min.
Or until we are satisfied that everything is working fine.
6.4 Take an access, drop in BigBigte sieve slit.
Reference cell filled with H2 gas, 150 psi.
Raster: ON. Beam current: 5-15 uA.
Take a few runs of H(e,e'). The expected BigBite "elastic" H(e,e') rate is ~ 20 Hz per 1 uA beam current.
Take a total of ~2.0 million BigBite triggers (or 1.5 hour maximum at 10 uA current).
6.5 Carbon single foil run, 5 uA beam, raster: OFF one run, 5 min.
6.6 Carbon multi-foil run, 5 uA beam raster: OFF one run, 5 min.
Verify that we can see each carbon foils in z_tar.
Is the sieve slit patteren visible ? (It's OK if the pattern is not clear).
6.7 While BigBite sieve slit is in, take one run with carbon multi-foil target and
BigBite field off, raster off. Reduce beam current to < 0.5 uA if necessary.
Take another run with carbon single foil target, raster:off, BigBite field off.
Coordinate with the target expert before turn off BigBite magnet in 200 A steps.
These runs help to define detector offsets.
Offline analysis: can we see tracks clearly ?
Operation time limit: 1 hour maximum with beam on. If we can't see clear tracks, move on.
6.8 At the end of this activity, make sure the HRS_L sieve slit plate is out already.
If necessary, make an access to remove the HRS_L sieve slit plate.
7. BigBite+HRS coincidence runs, (and single arm runs), optics study. E0=1.23264 GeV. (Should update beam energy with Tiefenbach Energy, recalculate the kinematics. X. Jiang 10/25/08) Kinematic table at /group/halla/www/hallaweb/html/experiment/transversity/wikifile/heep_transn_kinematics_102508.txt
HRS_L at 58.2 degree in POSITIVE polarity, P_HRS=0.61479 GeV/c. HRS_L sieve slit plate: OUT. (After energy loss corections already, X. Jiang 10/25/2008). Follow Operation Safety Processure while moving HRS_L to 58.2 degree, get tech on-call in the hall. Don't touch anything on the target, leave the RF coils alone. BigBite at 30 degree, 710 A current. BigBite sieve slit: IN, to start with.
Take all coincidence T5 trigger, take HRS_L and BigBite singles each at ~200 HZ.
7.1 Carbon single foil run, 5 uA beam, raster: OFF/ON one run each, 10 min.
For coincidence vertex reconstruction, check pointing offsets.
Offline anaysis: do we have a clear agreement between z_tar of HRS_L and that of BigBite ?
Does the reconstructed z_interaction show up different for raster IN/OUT ?
How much better can we correct z_int using beam infor from BPM+raster_current ?
This will determine our final z_tar cut in the production data.
7.2 Carbon multi-foil run, 5 uA beam, raster: OFF/ON one run each, 5 min.
Offline anaysis: do we have a clear agreement between z_tar ?
7.3 H(e,e'p) coincidence run, with reference cell H2 gas ~150 psi. raster ON 2mm by 2mm, beam current ~15 uA.
BigBite sieve slit: IN.
(Do we clearly see coincidence events ? If we are still having trouble identify coincidence events, take
an access, move out the BigBite sieve slit completely. Drop it in back again after we stablish the coincidence.)
Online replay: for T5 events, is the elastic proton peaks roughly at the middle of the HRS_L delta spectrum ?
We might need to slightly lower the HRS_L momentum to get more coincidence events.
Check coincidence trigger. Coin. Time-of-flight, S2M t0 offsets.
Beam RF timing signal check. Expected T5 rate is roughly: ~30 Hz on elastic peak for 15 uA beam.
Take 100 k coincidence trigger. Estimated time: 1 hour.
Offline anaysis: do we see the partial image of BigBite sieve slit in HRS_L \theta_tar vs \phi_tar ?
7.4 When we are satisfied with the coincidence time-of-flight spectrum, and the sieve slit image,
make an access, move out the BigBite sieve slit.
7.5 H(e,e'p) coincidence run, with reference cell H2 gas ~150 psi.
raster ON, beam current 1~5 uA. BigBite sieve slit:OUT.
7.6 Carbon multi-foil run, 5 uA beam raster: OFF/ON one run each, 5 min.
7.7 (Optional) Carbon single foil run, 5 uA beam, raster: OFF/ON one run each, 5 min.
7.8 H(e,e'p) coincidence and H(e,e') single arm run.
Reference cell H2 gas ~150 psi. raster ON, beam current 15 uA.
BigBite sieve slit:OUT.
Elastic rate for T5 is ~400 Hz, BigBite singles is ~25 kHz.
!!! Dropped OUT, (X. Jiang 10/24/08) !!!
Change BigBite magnet current, in 5 steps to ~20% of Max. (710A).
i.e. at 710A, 596A, 483A, 369A, 256A, 142A to have
elastic electron event spread over several rolls of lead-glass blocks.
These runs are for preshower+shower PMT gain calibration.
Take presacled BigBite singles, 1.0 million trigger each run (or 20 min each run).
Shower+preshower hardware gain adjustement through PMT high voltage changes.
Repeat runs at BigBite current 710 A, after HV adjustment.
Offline analysis: sotfware gain calibration.
Check trigger threshold settings.
7.9 !!! Dropped on 10/25/2008. X. Jiang. The downstream horizental RF coil bloks part of HRS view !!!
H(e,e'p) coincidence run, with reference cell H2 gas ~150 psi.
raster ON, beam current ~5 uA. BigBite sieve slit:OUT. BigBite magnet current: 710 A.
Keep beam current the same in these steps. Set prescale factors so that DAQ dead time is less than 15%.
7.9.1 One run with T5 only, nothing else. take 200k T5 (or 0.5 hour).
The expected T5 rate is ~25 Hz per 1 uA beam current.
7.9.2 One run with BigBite singles only, nothing else, take 1.0 million trigger (or 20 min).
The expected BigBite singles elastic rate is ~2 kHz per uA beam.
7.9.3 One run take all T5, and 200 Hz of HRS and BigBite singles. take 200k T5 (or 0.5 hour).
7.9.4 Same setting as in 7.9.2, turn all HRS_L mangets off. One run.
Take 1.0 million trigger (or 20 min).
Do we see any change in shower ADC spectrum ? HRS_L magnets might have an impact on BigBite PMTs.
Offlne analysis: do dead time corrections lead to consistant yields in these runs ?
Hopefully from this run, we can demonstrate consistency in dead-time corrections,
measure elastic cross section of H(e,e'p) and H(e,e').
7.10 At the end of these activities, change beaam pass to two-pass,
make an access to drop in the BigBite sieve slit,
make sure that HRS_L sieve slit plate is: OUT.
8. IF possible, take BigBite single-arm data at the same time of HRS single-arm data during polarized
target runs, as in steps 3.xxx. Make sure overall dead-time does not exceed 15%.
9. Two pass beam, BigBite+HRS coincidence runs, optics study.
E0=2.400 GeV, beam polarization is not an issue. Beam tuned through Compton magnet.
(Should update beam energy with Tiefenbach Energy, recalculate the kinematics. X. Jiang 10/25/08)
Kinematic table at /group/halla/www/hallaweb/html/experiment/transversity/wikifile/heep_transn_kinematics_102508.txt
Moller quards off (? ask Eugene Chudakov to confirm).
HARP scan to verify beam intrinsic spot size.
We don't need the polarized He3 target in two-pass calibration runs.
HRS_L at 46.37 degree in positive mode, P_HRS=1.23337 GeV/c, HRS_L front sieve slit:OUT.
BigBite at 30 degree, NEGATIVE polarity, magnet current 710 A. Front sieve slit:IN. !!! Remember to drop in BigBite sieve slit during the pass change. !!!
Take all coincidence T5 trigger, take HRS_L and BigBite singles each at ~200 HZ.
9.0 Beam delivery procedure for two-pass beam.
Not to tune through Compton magnets (X. Jiang 10/25/2008).
Moller quards: OFF (confirm with MCC+Eugene).
Carbon hole target run to establish norminal beam+target center.
Raster size change on reference cell to determine the best raster size.
9.1 Carbon single foil run, 5 uA beam, raster: OFF/ON one run each, 5 min.
For coincidence vertex reconstruction, check pointing offsets.
9.2 Carbon multi-foil run, 5 uA beam, raster: OFF/ON one run each, 5 min.
9.3 H(e,e'p) coincidence run, with reference cell H2 gas 150 psi. raster ON, 2mm by 2mm, beam current up to 15 uA.
BigBite sieve slit: IN.
(Do we clearly see coincidence events ? If we have trouble identify coincidence events, take
an access, move out the BigBite sieve slit completely. Drop it in back again only after we stablish the coincidence.)
Online replay: for T5 events, is the elastic proton peaks roughly at the center of the HRS_L delta spectrum ?
Might need to slightly lower the HRS_L momentum to center the peak in delta.
Check coincidence trigger. Coin. Time-of-flight, S2M t0 offsets.
Beam RF timing signal check. Expected T5 rate is roughly:3 Hz.
While BigBite sieve slit is in, take one run with carbon multi-foil
target, BigBite field off in 200 A steps, inform target experts first .
Reduce beam current to < 0.5 uA if necessary. 0.5 million triggers (or 20 min).
Offline analysis: can we see the BigBite sieve slit's central hole clearly ?
Take another run with single carbon foil target, I < 0.5 uA, BigBite field off. 0.5 millon triggers (or 20 min).
9.4 When we are satisfied with the coincidence time-of-flight spectrum, make an access,
take out BigBite sieve slit.
9.5 H(e,e'p) coincidence run, with reference cell H2 gas ~150 psi.
raster ON, beam current 15 uA. BigBite sieve slit:OUT.
T5 rate: ~30 Hz, BigBite singles rate: 1 kHz.
9.6 Carbon multi-foil run, 5 uA beam raster: OFF/ON one run each, 5 min.
9.7 (Optional) Carbon single foil run, 5 uA beam, raster: OFF/ON one run each, 5 min.
9.8 H(e,e'p) coincidence and H(e,e') single arm run.
Reference cell H2 gas ~150 psi. raster ON, beam current 15 uA.
BigBite sieve slit:OUT.
Take several runs, until the experts (Kalyan++) are satisfied with the coincidence data.
!!! Dropped OUT, X. Jiang 10/24/2008 !!!
Change BigBite magnet current, in 6 steps, i.e. at 710A, 596A, 483A, 369A, 256A, 142A to have
elastic electron event spread over several rolls of lead-glass blocks.
These runs are for preshower+shower PMT gain calibration.
Take presacled BigBite singles, 1.0 million trigger each run (or 20 min each run).
Shower+preshower hardware gain adjustement again.
Sotfware gain calibration.
Check trigger thrshold.
9.9 H(e,e'p) coincidence run, with reference cell H2 gas ~150 psi.
raster ON, beam current 1~5 uA. BigBite sieve slit:OUT.
These runs are for cross section measurements, hoe to understand cross section to +/- 5-10% level
Keep beam current the same in these steps.
9.9.1 One run with T5 only, nothing else. 15 min. 9.9.2 One run with BigBite singles only, nothing else. 15 min. 9.9.3 One run take all T5, and 200 Hz of HRS and BigBite singles. 15 min.
10. E0=5.900 GeV, polarized beam, pre-production check out (1 day).
Beam energy lock: ON, lock on Hall A.
HRS_L at 16 degree, NEGATIVE polarity. P_HRS=-2.4 GeV/c. Front sieve slit:OUT.
BigBite at 30 degree, NEGATIVE polarity, I=710 A. Front sieve slit:OUT.
10.1 Beam tune through Compton magnets, Compton detector commisioning.
10.2 ARC beam energy measurement (Arun Saha).
10.3 HARP scan in the Hall, verify beam intrinsic spot size.
10.4 Moller run.
And a run with a large beam charge asymmetry, with HRS coda, Moller taking runs at the same time.
To verify the sign of beam helicity signal between different system.
(Eugene Chudakov and Bob Michaels, should repeat several times throughout the experiment).
10.5 Beam position vs BigBite background rate check.
Using polarized He3 cell, to establish the nominal operating beam position.
Start from the nominal beam position establised during one- and two-pass beam delivery.
10.6 Coincidence trigger check.
Carbon multi-foil target, Beam raster:ON. Beam current: 1~5 uA.
Offline analysis: check coincidence time-of-flight corrections. do we see (e,e'p) coincidence ?
protons reach HRS focal plane 8 ns later than pions.
With enough confidence, shrink TOF window from 100 ns to ~60 ns(?). Keep protons in the TOF window.
The goal of on-line corrections is to have the corrected TOF resolution to 2 ns (sigma).
10.7 Pol. He3 target, transvers in plane polarization, spin-flip check.
Offline analysis: All scalers make sense ?
Lumi reading can be clearly lined up with real triggers in time ? FAst clock serev as time marks.
The DAQ goal is to take at least 1 kHz (100 Hz coin.+900Hz singles) with 85% live time.
10.8 Are we done with the commisioning ?
10.8.1 BigBite detectors are all working, first order optics roughly working,
clearly see carbon foils and sieve slit patten.
10.8.2 HRS_L detectors are all working.
10.8.3 Coincidence trigger works. All scalers make sense.
10.8.4 Target is polarized, spin-flip is working fine.
Move on to production runs.
11 Production, target transverse polarized, in-plane left/right and verticle up/down.
With reference cell runs in between, H2 gas 110 psi, He3 gas 110 psi (?), N2 gas 110 psi.
Basic principles guiding the decisions for production run, changes include:
i, HRS_L polarity change, equally split beam charge between HRS_positive and
HRS_negative runs.
ii, Beam half-wave plate IN/OUT changes, equally split.
iii, target holding field UP/DOWN runs (?), equally split.
iv, target up/down vs left/right, equally split.
v, Roughly 10% of beam time on reference cell runs, H2 gas 150 psi.
Or, whenever the polarized target is down.
For relative yield ratio measurement for dilution factor corrections from He3 to neutron.
Reference cell runs are preffered to be taken durng the recovery of polarized He3 target.
The "true target-spin-flip" should be turned off to prevent target polarization loss.
However, the "target spin-signal" should be on for false asymmetry measurements.
12 Change target cell.
13 Production.
With reference cell runs in between, H2 gas.
14 Do we have enough calibration data ? (Xin Qian, by Jan. 12th, 2009).
15 Complete data taking, switch over to d2n, change cell, with Long. target polarization setup.
16 One pass beam again, polarized, repeat He3 elastic asymmetry calibration.
17 change to d2n production ...
Trigger types:
T1 = BigBite Total shower T2 = BigBite Total shower + Cerenkov overlap T3 = L-HRS Singles (S1.and.S2) T4 = L-HRS Efficiency (S1.or.S2) T5 = T1.AND.T3 (BigBite LHRS Coincidence) T6 = BigBite Total shower 2nd trigger(different threshold than T1) T7 = BigBite Cerenkov only T8 = 1024 Hz pulser T9 = BigBite cosmics(front-back) T10 = BigBite cosmics(top-down)
