Pion Meeting April 22 2022 3:30PM ET

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Zoom link: https://jlab-org.zoomgov.com/j/1608212513?pwd=M25LR1hzN3hLWm0xaFFETjZ0U1lQZz09

Agenda

Agenda:

1. Update on prototyping the pion detector, still blackening the Lucite is in progress- (Elham)
2. Comparing rates from different generators (beam, Moller, pion, elastic, and inelastic) with different analysis methods (python analysis and root analysis)- (Raj)
3. Update on Fair Sampling - (David) [1]
4. AOB

Attendance

Elham, Wouter, Raj, David, Jim, Neven, Sudip

Minutes

1. Continued work on setting up for cosmic studies of lucite. Some issues with understanding calibration of trigger scintillator signals. Idea (David): compare to expected cosmic rate of 1/cm^2/min for horizontal detector, to ensure signal dominated by cosmic muons. Don't really understand auto-trigger mode of the CAEN digitizer, but self-triggered spectra look reasonable for scintillators. See what appears to be cosmic muons in the acrylic. Idea (Neven): should one try using LED pulser to calibrate single PE peak? Will start with selective blackening studies soon.
2. Comparing rates at lucite for various generators, Raj finds significantly larger rate for the beam generators than from the sum of the individual process generators. Is this beam-pipe or beam dump background? Idea: look at p_z=negative events, and vertex locations to see if this is beam dump or beam-line background.
3. David sees, again, imperfect "fair sampling" of pion momenta with latest version of pion detector/donut geometry. Some of this might be improved by moving lucite radially outward somewhat. Idea (David): look at open/transition/closed pion detectors to see if one get empirical handle on any momentum-dependence of asymmetry. Still don't understand the events that appears in the lucite which were generated at theta > 0.023 radians (i.e. outside nominal acceptance). Idea (Jim): replace primary collimator with kryptonite in the simulation.
4. AOB: We might want to try Phythia-8 as alternative source for pion generator (Wouter).
5. AOB: Ryan B. had asked David if the thickness of the Al fins that connect the pion donut to the beam pipe could be increased from 1/2" to 3/4" or 1". In discussion, we confirmed that there appears to be little Moller leakage background coming from this region... when the frame materials were changed to "Galactic" in the simulation, the leakage rate did not significantly change. Also, don't see "image" of the fins in our plots of vertices for leakage events. So, this change is likely OK for pion detectors.