Difference between revisions of "Dec runplan"

Latest revision as of 12:00, 20 December 2011

E08-027/E08-007 Commissioning Runplan

Goal : Commission the beamline diagnostics (BCM, BPM, tungsten calorimeter, super-harp slow and fast rasters, Moller polarimeter), the septa magnets, the spectrometer detector stack, the 3<math>^{rd}</math> arm detector and all associated control/DAQ systems for E08-027 and E08-007. The polarized target, local dump and FZ chicane magnets will not be commissioned at this time.

Task I : Initial Delivery (9 shifts)

The initial delivery of beam to Hall A will be directed by Accelerator Ops, with assistance from the Hall A shift crew. This includes delivery of beam to the dump, commissioning of the BPMs, calibration with the Harp and power up of the rasters.

Full details are provided at:

• Initial Delivery Testplan (Y. Roblin). Some further details are here.
• Tungsten Calorimeter Testplan (M. Ahmad)

Start up configuration

1. Three pass beam, E0 =1.721 GeV, polarized, no raster.
2. Current: Initially pulsed up to 8<math>\mu</math>A pulsed, then up to 5 <math>\mu</math>A CW.
3. Spectrometers at 12.5 degrees, <math>P_0=1.720</math> MeV (carbon elastic).
4. Carbon Target: OUT.
5. Sieve slits : OUT.
6. Septa settings: 5.69 degrees.
7. Compton chicane: OFF (straigt-thru).
8. Polarized Target chicane : OFF and degaussed. (straigt-thru).
9. Tungsten Calorimeter : Retracted.

Collab responsibilities:

• Request slow raster radius : 1 cm. Fast raster : 1 x 1 mm<math>^2</math>.
• Checkout Happex BPM crate. ( Resp: A. Camsonne, P. Zhu)
• Request slow energy lock. Monitor Happex asymmetry feedback.
• Confirm final beam energy for delivery.
• Shift will need to run spot++.
• Start Detector checkout parasitically using scattering from <math>^4</math>He flowing in the target chamber.

Task II : Moller Commissioning (2 shifts)

Test plan of Sasha Glamazdin for Moller measurement at three-pass beam.

1. Moller settings, HV adjusment - 2 hours
2. The first Moller quad scan - 1 hour
3. The third Moller quad scan - 1 hour
4. Moller target scan - 30 min
5. New DAQ dead time test - 2 hours
6. Restore the beam parameters - 30 min

Hall A Shift Responsibilities:

1. Determine absolute beam helicity signs in Hall A.
2. Large asymmetry run. 1 hour. (Resp: Alex).
3. Record beam half-wave plate IN/OUT changes during data taking.
4. Verify that Wien filter angle and beam half-wave plate status are in EPICS data stream.

Task III: HRS/Detector Checkout

Some of these tasks can be performed parasitically to previous tests. There should be some usuable rate coming from the helium in the PVC pipe.

Hall A Shift Responsibilities:

1. Verify that FZ1 and FZ2 chicane magnets are configured for no deflection (‘straight-thru’ mode).
2. Insert 10 mil carbon foil target. ( Resp: Ed )
3. Spectrometer Magnets ( Resp: Jack, John )
   1. Test Quad and Septa cycling. 3 hours.
   2. Septa field correspondence to HRS. ( Resp: Jixie, Min.)
4. Set momentum to carbon elastic setting, <math>P_0=1720</math> MeV.
5. Request CW beam at 1 <math>\mu</math>A. No raster.
6. Adjust prescalers to obtain deadtime less than 10%. Verify DAQ rate is greater than 4 kHz.
7. Continuos online replay. Take 2 M good events per run, but atleast 15 mins for each run. No run longer than 1 hour.
8. High rate DAQ tests. 3 hours. ( Resp: Vince, Ryan).
   1. Minimize DAQ readout time, reduce deadtime.
   2. Record deadtime as a function of DAQ rate. Change rate via current or prescalers.
9. Trigger Checkout. ( Resp: Alex, Vince, Ryan, Melissa).
   1. Check deadtime via the scalers.
   2. Verify that all scalers are incrementing.
   3. Check for double pulsing.
   4. Check scalers: detector, triggers, charge, etc. ( Resp: Pengia, Vince).
      1. Online dead time calculation make sense from the scalers. (Use SRC deadtime software.)
10. Lumi checkout ( Resp: Kalyan, Pengia).
11. 3rd Arm checkout( Resp: Kalyan, Chao, Jixie). Prior to beam perform Hall probe measurement of magnetic fields at PMT location, and Mu-metal shield optimization.
    1. Put Al shielding in place before locking-up the Hall.
    2. Detector checkout with beam (check rates, helicity scalers, bcm, deadtime measurement etc..)
    3. HV adjustment if any (done with cosmics already)
    4. Threshold check (unfortunately, we don’t have remote threshold control, so need to go to the hall each time we change threshold)
    5. Check trigger (dE.AND.E) rates and understand optimal conditions to run vis-a-vis prescales vs deadtime.
    6. Check to see if buffering can implemented ( This in principle can be done before beam come to the hall)
12. Helicity ( Resp: Chao, Pengia).
13. HRS Detectors ( Resp: Alex, Vince, Melissa, Ryan) : 6 shifts.
    1. VDC ( Resp: Ryan).
    2. Gas Cerenkov ( Resp: Melissa)
       1. Gas shed checkout procedure (Resp: Jack)
       2. PMT HV gain-matched.
       3. All ADC and TDC channels have signal?
       4. Compare NPE to old short tank results.
    3. Pion rejector / Calorimeter ( Resp: Melissa).
       1. PMT HV gain-matched.
       2. All ADC and TDC channels have signal?
    4. Scintillator ( Resp: Ryan).
       1. Timing offset of S1 S2M.

Task IV: Optics Commissioning : 3 shifts

( Resp: Jixie Zhang, Min, Chao). This will be a limited commissioning of the spectrometer and septa optics. To be performed only if time available.

By Jixie: The sieve slits are not in position in this commissioning. What we can do here are the following:

1. Beam cross scan (OPs will steer with correctors and quads) 2 shifts

Try to change beam position with slow raster. At each beam position, take data for delta=0. 

1. Verify initial optics database. iterate. 1 shift.

Make a delta scan when beam position at (x=0,y=0), set delta to -4%, -2%, 0, +2%, +4%

V: Carbon Inelastic Spectrum and False Asymmetry

( Resp: Karl)

1. Acceptance scan. Sequentially shift momentum setting by factor 1/3. 1 shift.
2. Adjust Prescaler to bring deadtime below 10%. Prescaler should be approximately in range 1-10.
3. Take full spectrum of carbon, covering the elastic and accessible inelastic region. See Table below for kinematic settings. Take 2M good events per setting, with a minimum time spent on each point of one hour.