Notes from Meeting Mar 20, 2009

• Announcement :   Parity Collab Meeting Apr 17-18

• Simulations

• Dustin made comparisons of VDC hit distributions to projections from focal plane; results look good and confirm understanding of how Podd works.
• He projected the simulated data to Z of detector (42.5 cm from focal plane).   Idea here is to design the PREX detector.
• Dustin showed some initial comparisons of Guido's transport versus LeRose's transport (see the HAPLOG).   A work in progress.
• With LeRose's help, Dustin plans to tweak Q3 to optimize the spot size at the detector. Ideally Y would be thin enough to match a PMT. Q3 should expand one dimension and shrink the other.

• ADC Testing at JLab

• Luis is studying the linearity of the integration time scan.
• We'll get 4 more ADC18 soon, to be tested. (And 10 more arrive in June.)

• Optics Studies at UVa

• Rupesh reported on how laser beam RMS changes in a linear-array photodiode (see HAPLOG).
• Large asymmetries at distances far from the center of the spot has a significant pull (~10%) on the centroid.
• Questions regarding how the UVa setup compares to the Jlab setup and whether we can reproduce the JLab setup, which might not have the same tails. Questions also about how the tails transport.

• Nonlinearity of PMTs at CMU

• Brian Quinn reported a breakthrough in how efficiently they can study the nonlinearity of PMTs. Studies that took hours before now take minutes.
• Will soon show the effect of HV, rates, etc on the nonlinearity (~2%) and how reproducible and correctable this is.

• Compton Electron Detector

• Alexandre summarized what is known about the electron detector, see the HAPLOG.
• There is a correlation between the observed trigger rate and beam on/off, but not with laser on/off, suggesting we have a lot of background but little or no signal from Compton events.
• Worse, there are no discernable tracks.
• Plan during shutdown to shine a hot source at the detector and see if he can find tracks.


Comments to: Bob Michaels