Log entry time 20:24:44 on December 12, 2003

Entry number 70848

Run Coordinator's Report - 12 December 2003 18:20

General Comments/Problems/New Information

Problems

• The Hall C chopper slit is defunct so we are now getting our beam through the Hall A chopper slit. This means that we will be without beam for 8 hours Sunday day shift while the MCC runs an energy spread minimization program to Hall A. There will likely be a long access on Monday to repair this and install other equipment in the injector.
• Some of the data taken on owl shift was with the DAQ in "ts_scaler" mode rather than "ts_full". This means there is no French TE or Fastbus data for those runs. The DAQ should never be in "ts_scaler" mode unless explicitly called for in the run plan. If you do switch to "ts_scaler" make sure you switch back to "ts_full" at the completion of your program. Here are the nominal settings we should be using on the DAQ.
  • Configuration mode in runControl GUI should be "ts_full", not "ts_scaler
  • G0 DAQ Configuration Tool GUI
    • 30 Hz mode enabled.
    • Fastbus prescaler (PS4) = 5000
    • Fast clear disabled
    • GMS prescaler (PS5) = maximized
    • NA CFD threshold setting = 7
    • NA CFD width setting = 0
    • DMCH Reference Config = Threshold-FiB_Buddy-NPN-ON-50mV
• A couple of hours of beam were lost this afternoon because the operators were trying to tune to old nominal beam positions in the hall. Once the mistake was discovered by our shift crew beam was recovered rapidly. I'll follow up on this with the PD tomorrow. For informational purposes the nominal beam positions in the hall are in g0log 70558.

New Information

• We need to specify what data we are taking when we ask the MCC to reduce the beam current below 40 uA: Moller or other (say background). They use the slits to reduce current for the Moller and reduce laser power in all other instances. If there is an indication that there are tails on the beam after reducing the current with the laser, then you can ask them to tweak the prebuncher setting a little. We should start paying more attention to halo rates I think as an indication of beam tails.
• In order to take data on the tungsten radiator we will probably have to take an access and reset the target FSD box so that the "target in" position is centered on the radiator rather than LH2. This means we have to group all of our radiator runs into long blocks because we will not be allowed to do this often. This situation will be remedied after the new year when a new FSD box arrives that allows for multiple target positions.

Past 24 Hours

Swing

Shift started waiting for beam while the MCC completed the daily G0 Beam Health Checkup and ran a 30 Hz PZT test (the test failed and further tests have been suspended pending a resolution). When beam was given to the hall Greg Smith commissioned the tungsten radiator (g0log 70699) while Paul and Dominique did DAQ test involving the 9th DMCH board (70745). The flyswatter had been put in during day shift access so we tried to take hour long runs on radiator+FS (successful) and LH2+FS (failed due to loss of beam). At this point the MCC began diagnosing problems with the chopper slit that eventually caused us to move to the Hall A chopper slit (elog 1185419). The flyswatter was removed and there was no more beam swing shift.

Owl

Beam came back at roughly 02:30 at which point Kaz was in to do RHWP/IA/PZT scans and start the beam feedback. A different approach was taken to setting the RHWP where essentially the position difference that we have little control over was minimized rather than the charge asymmetry (details are slightly more complex but that is the gist). We then took long feedback runs for the rest of the shift with very promising results (g0log 70795 and 70821). Over a period of about three hours we were able to control the position differences to less than 20 nm. These feedback runs were taken with the LH2 target in so we have some TE data on LH2. Unfortunately, these were the runs taken in "ts_scaler" rather than "ts_full" so there is no French time encoding or Fastbus data. Also attempted to take a long run on the radiator but were not allowed to do so by the MCC. The problem is that mentioned above; that by default the target in FSD position is LH2. Without resetting the FSD box it is necessary to mask the target FSD. This cannot be done without also masking the ion chambers and the magnet vacuum which is not a safe mode for the machine or the experiment to operate in.

Day

The day shift was lost to the switch from the Hall C chopper slit to the Hall A chopper slit. There appear to have been issues with coming back up from that. Also, as mentioned previously a couple of hours were lost due to the attempt to tune to incorrect nominal positions in the hall.

Future Plans

Friday Swing/Saturday Owl

1. Deadtime studies that were punted from the previous swing.
2. Another RHWP/IA/PZT scan followed by more long runs. This will be capped by another IA/PZT/RHWP scan to check stability of the calibration parameters.
3. Time permitting the flyswatter will be put back in to get the LH2+FS data that were punted on the previous swing. Will take hour long runs at two magnet currents (5000 A and 4500 A).

Saturday Day

Moller Systematics

Saturday Swing

1. Deadtime studies.
2. Another RHWP/IA/PZT scan followed by more long runs. This will be capped by another IA/PZT/RHWP scan to check stability of the calibration parameters.

Sunday Owl

Continuation of previous shift program or the CFD threshold program necessary for Q2 and centering.

Sunday Day

Hall A energy spread minimization will be going on so there will be no beam. We will use the opportunity to access the hall for GMS checkout and TLD removal.

Sunday Swing

1. Halo target centering
2. Halo monitor calibration
3. Target density test