Notes from Local Meeting on Jan. 29, 2004

• Septum Status - Tim

  • Recent control problems. Readback appeared frozen. Experts are still working on it.
  • Cooling is still a big issue (Left Septum cooling every 12 hours)
  • Right septum heats up when running with waterfall target, so it was necessary to run at 60 uA instead of 100 uA with this target

• Hall Status

  • Recent problem with vacuum leak on Left HRS Q3. Probably will take several weeks to replace.
    There is some rumor/speculation (propagation continued here) of the possible effects on the HAPPEX start date, including a scenario with an earlier start of HAPPEX.
  • Also some rumor/speculation about G0 gaining an additional 39 calendar days (15 or so PAC days) of production running, to make up for inefficiencies in beam delivery and the need for more background studies than originally anticipated.

• Lumi Hardware - Hachemi

  • Shows how the helium purge line will connect to the Lumi PMT.
  • May use a scintillator to look at test pulses from the PMT.
    This arrangement may also be useful for Bryan's Signal Width-HAPPEX ADC study
  • Light guides have not arrived yet.
  • Here's a figure showing the lumi construction (light_guide_PMT.eps).

• Lumi Analysis - Bryan

  • Lumi Normalized Asymmetry RMS on the H₂0 target is nearly 14000 ppm.
    Could be boiling... could be variation in target thickness due to the unconstrained nature of the target.
  • BCM Asymmetry RMS appears to have gotten smaller (~700ppm)
  • For Carbon target, Normalized asymmetry RMS is around 200ppm
    Will check to see if this agrees with Riad's estimate.
  • Will also trying running with the Prototype lumi, to find out:
    • Why one back lumi has a smaller RMS than the other.
    • Why regression slopes (vs bpm4bx) are the same sign in both back lumis (they're on opposite sides of the beam pipe).

• GDH Analysis - Ryan

  • Finished with spreadsheet documenting each run.
  • Learning about submitting jobs on the computing farm

• Laser Room - Lisa

  • Laser Room AC is back in service
  • Pockels cells are hygroscopic, therefore it is necessary to be careful to protect windowless cells from a humid environment (e.g. laser room w/ broken AC)
  • We are ordering 2 new cells from Cleveland Crystals this week

• PAN

  • Bryan wants to separate the Dacnoise and Pedestal subtraction from the ADC calibration variables in the ROOT Tree.
    This will be helpful for BCM/BPM/Lumi Calibrations.
  • Will check with Rich to see if he has any objections before the change is made