Notes from Local Meeting on Mar. 12, 2004

Announcement:

It was agreed that Thursday, 11 am, was a suitable weekly meeting time. Please contact Kent Paschke if this is not generally compatible with your schedule.

• Target Status - David
  

• Questions were raised about non-uniform windows on top racetrack cell (cell block number 1), which had obvious non-uniformity in the windows. This was the He cell, with thicker windows than the other. This cell could not be soldered to the block (electroplating failed); it was welded instead. Windows have withstood pressure tests.
• Beer can cells (15 cm, 4 cm) probably wanted for two days during hypernuclear (by hypernuclear experiment). This would conflict with our hope for a test of the 20 cm Racetrack cell.
• Questions remain concerning the alignment of beer can cells on the target ladder

• Tim

• Working on optics for Hypernuclear, working out bugs in transferring over to C++ analyzer (from ESPACE) but everything is looking good overall
• Bob raised the issue of estimating the systematic uncertainty from optics calibration. This could impact the systematic uncertainty in Q^2 determination. No conclusions were reached.
• Has begun understanding mySQL code. Will discuss plans/specifications for mySQL database implementation (run configuration, run analysis results) and start work on this.
  
• Concerning optics, Tim, Doug, Rob, and Nilanga will review the reasons for sieve-slit running.
• Tim, Doug, and Nilanga will also discuss the desired configuration for the multi-foil Carbon target.
• David will check that the multi-foil C target can be reconfigured for HAPPEX.

• Lisa

  • UMass crew comes next week to install Q² scanner
  • Doing lots of tests with Arwen in laser room.

• Rob

• Spoke w/ Dave Meekins who will order Kapton foil
• Dave will also look into a Titanium Hydride target. This would be a powder in a container with thin foil windows.
  

• Ryan

  • Has some good data of charge asymmetries from GDH run
  • From now on, will focus on work in laser room since its higher priority
  • Also, doing calculations concerning things of interest with the source
    

• Hachemi

• All 8 Back lumi detectors are installed
• Showed data taken to verify that each lumi was cabled correctly
• Will continue to look at pedestal noise
• Will start looking at issues with PANAM 
• David wants to use before and after measurements of quartz pieces in the lumi the measure transparency loss due to radiation damage. This will be useful for both Lead and Qweak detector development.

• Bob

• Worked with Musson to plan cabling for cavity monitors. Cabling will be completed soon. Musson is confident that cavity electronics will be available by April 15.
• New Cavities in BSY will be cabled to Counting House, cavities near target will be cabled to Left Spectrometer.

• Bryan

• HAPPEX crate for left spect. was installed; seems to work fine
• Will move two ADC's to Left spect next week
• ADC gains to be set to accommodate desired ranges. For two ADCs:
• for hydrogen - 2 channels, gains set to integrate 20 microamps @ 30 Hz
• for helium -1 channel, gain set to integrate 6 microamps @ 30 Hz
• 1 profile scanner, current range not yet determined
• BCM signals for the 10kHz down-converter will be available to the Parity DAQ from the V2F fanout used by the spectrometer DAQ. This will allow direct comparison with the (old) 1 MHz down-converter during April Hypernuclear run.

• Kent

• Continuing work to design collimator
• SNAKE and David's MC are being used.
• Trying to balance loss of rate with reducing the interaction on the septum bore, also planning for possible mis-alignment of target, collimator, septum, or beam.
• Collimator redesign was necessary last week. Acceptance-defining collimator is now relatively thin (1 inch), and shielding function is performed by separate blocks which should not affect acceptance. All planned septum heat shielding is installed, or will be installed soon.
• Suggested tests during Hypernuclear
  • test the Compton: signal/noise ratio
  • test dithering
  • beam monitor tests
  • Cryotarget test

• General Issues

• Thinking of moving local meeting to Thursdays
• SVT lattice has good QE after first test
  • promising start, but to avoid complications, the cathode is not anodized.
  • QE is comparable to that of strained GaAs, so still factor of 3-5x less than what superlattice should be capable of.
  • Combination of lower QE (requiring higher laser power) and no anodization may lead to shorter cathode lifetime.
• New labels for lumi monitors
  • FLumi -- refers to FRONT lumi, near target
  • BLumi -- refers to BACK lumi, 7 meters behind target
• G0 certification report:
  • Position differences integrated over 100 hours each for IHWP in and out are at or below 10 nm, before cancellation.
  • Regression slopes for each detector octant are reasonably constant, agree with dithering slopes, and are reasonably consistent with geometric considerations of the azimuthal positions.