Pion Meeting July 12 2023 1:00PM ET

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Zoom link: contact David Armstrong, Elham Gorgannejad, or Jennifer Finch for the link.

Agenda

1. Updates on the modified mechanical design of the pion detector prototype - (Elham)
2. Thermal neutron flux at pion detector (GEANT 4) - (Sayak)
3. Asymetry values at the pion detector system - (Elham)
4. AOB

Attendance

1. Elham, Wouter, David, Crl, Sayak

Minutes

1. (Elham) Has 3D printed a section of the "cavity" in the Pb donut. Will try test-fit with pion detector mock-up. A detector with 1.5" diameter PMT as was used in beam-test prototype will not fit, but the 29.2 mm diameter (1.13") ET 9125QB should fit (make PMT holding piece smaller diameter). Probably need 1 mm space around lucite inside enclosure for tyvek wrapping. Some discussion of tweaks to fillets on enclosure. Plan will be to also test light-tightness of the 3D-printed only design. Discussion of which 3D printed material to use (quotes for cost per module vary by up to factor of 20 depending on material, but even the most expensive is within our budget. PLA is cheapest, ABSplus most expensive. Main detector is using nylon 15 plus carbon fibre; what is ShowerMax group using? Might be able to "piggyback" production on Main Detector production at U. Manitoba.
2. (Sayak) GEANT 4 studies with beam generator, and including pion donut, showerMax materials. Total thermal neutron flux at location of pion detector PMT windows is 1.77 MHz/cm^2 at 65 muA; only about factor of 2 larger than Neven's Fluk simulation, which only included beam dump. Next steps are to restrict the active area of the virtual detector to the region in the Pb donut cavity (to avoid direct shine from showerMax at inward radial locations, for example, and to extend the plots with vertices to larger values of v_Z to look into beam dump area. Is using the default physics lists - should check with Ciprian to mae sure this is best practice for low-energy neutrons. May want to try simple test of the effect of adding the Pb around the main detector PMTs (to ensure that is also not a neutron source for our pion detectors). Aside: someone should eventually update the remoll geometry for the support stand for the Pb donut to match better what is being built.
3. (Elham)Developing tools for Bayesian analysis of MOLLER simulated data. Looking at asymmetry distributions for Moller events seen by pion detectors. Some initial puzzles - should compare with asymmetries seen by Ring 5 (and, eventually, all the main detector rings).