MOLLER Pion Background Meeting Wednesday, October 5, 2016 3:00pm EST
MOLLER wiki home:MOLLER_at_11_GeV_E09-005
Previous Meeting: MOLLER_Pion_Background_Meeting_Thursday,_September_22,_2016_3:00pm_EST
BlueJeans Call Information
Phone Number: 1-800-240-2560
Meeting ID: 624029893
- Scott: Implementation of lead wall and strawman pion detector.
- Jacob: Starting to work on pion simulations.
- Initial plan: Implement single septant pion detector behind lead wall.
- To be placed behind Moller ring to begin with.
- Lead tungstate(PbWO_4) blocks.
- Wouter's initial concept of the pion detector geometry. (See previous meeting page for details)
- Any new business?
Attendees: Mark P., Rakitha, Kurtis, KK, David, Seamus, Jacob, Scott
- See Mark P. recent email for some notes on a discussion he had with KK. Will discuss more in the future.
- Scott currently working moving his lead wall and pion detector into it's own separate gdml file. Figured this would be best for future development.
- Jacob just starting on getting up to speed on the remoll simulation. Will take Scott's pion straw/wall detector and due simulations at 400 and 500 mm lead wall thickness. Planning to investigate the length of the prototype detector module, for cost estimate.
- David: Jim Dowd, working on Qweak, has a preliminary transverse pion asymmetry that is on the order of 10-20 ppm. Meaning it could be larger than the pion PV asymmetry by a factor of 2 to 10.
- KK: Need a systematic correction for the pion background also needs to bound the hyperion contribution.
- KK: Shower max and electron suppression should be talked about in terms of radiations lengths. At the 10^-4 level.
- Looking at https://dilbert.physics.wm.edu/MOLLER+Simulation/67
- What should the P/E ratio should be? Take a look at the notes from Mark P.(see email):
- What is the optimum way to extract N_pi/N_ee from remoll.
- KK: Suggests that we need a defined method for extracting these values.
- David's concern, particle ID detectors can be difficult to determine the dilutions.
- Thinking we need to know N_pi/N_ee ratio at the 10% level (for the dilution).
- 0.2 ppb uncertainty is the goal for the pion correction to A_ee
- Dilution could be measured with coincidence with MIP in the shower max with pion detector. See third bullet point from the notes.
- Simulations should be done with the shower-max/temp. stand in to check MIP coincidence.
- Single GEM plane could be used with rotator for pointing measurement to shower-max.
- KK: Doesn't think there is any crazy reason why the pion distribution should change wildly with phi.
- David: Just putting a pion detector for Moller ring, then order of magnitude correction for other rings could be down with simulation for a given normalization taken from measurement in the Moller ring and pion detector.
- David: Will have to revisit the Yuxiang's pion correction for the simultatous ring extraction, in the future.
- Paul: Interested in the energy spectrum of the pions going through the main detector rings. KK recalls energy between 1-2 GeV.
- KK: This should be confirmed in the future.
- Paul: What is the dE/dx for these low energy pions (lower than SLAC's pions)? Can be answered soon.
- David: We should be able to produce these plots soon. Definitely different lower energy spectrum than what SLAC saw.
- David: How worried(Paul) are you about pion transverse asymmetries? Paul: Worried about it, thought about it a bit.
- Paul: Could probably get away with a minimum of three detectors. KK: Full coverage would be better. David: Should segment behind open/closed/transition sector for a given septant as a base line.
- KK: Two step process - Make intial guess with best available numbers. Then do the full study.
- David: Lead glass for PbWO_4, estimate the cost for each? Radiation problems with lead glass, maybe anealing might work in this application.
- Radiation worry for the lead glass could come from the background in the hall.
- Paul: HAPPEX style shower detector might work.(Lead lucite) David: Depends on how much calorimetery we would need?
- HAPPEX 2 used quartz detectors.
- KK: Could sacrifice the stat. width with a low cost design that reduces energy resolution.
- We are looking for one to one for the light response.
- Measure the integrating asymmetry everywhere, only need to counting measurement in a few septants.