Pion Meeting May 31 2023 1:00PM ET

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

Agenda

1. issue of borosilicate vs. quartz windows for the pion detector PMTs and thermal neutrons: [1],[2]
2. quotes on PMTs from ET
3. status of PMT testing at JLab
4. AOB

Attendance

David, Dustin, Sudip, Wouter

Minutes

1. Discussion of need for quartz windows vs. borosilicate windows for pion detectors. Dustin points out that one reason for using fused silica (quartz) instead of borosilicate glass for the MD and shower-max PMTs is the increased radiation hardness - this will not be an issue for the pion detectors, with our much lower radiation dose. Dustin suggests the idea of testing PMTs for thermal neutron capture events at the Idaho State accelerator - he will inquire about what the expected thermal neutron fluxes are at that facility when medical isotope production runs are underway... maybe we can do parasitic tests. Still unsure if quartz windows is essential for pion detectors.
2. Have quotes from ET - quartz windows for the ET 9125QB compared to the UV glass ET9125WB ciost a factor of 1.75 more. In each case the envelope is from borosilicate glass. According to the ET rep, only the window is fused silica and it is attached to the borosilicate tubing via a series of graded seals that afford a progressive matching of the coefficients of expansion. The entire PMT can't be made of quartz because borosilicate glass has to be used to make reliable vacuum joints to the pins on the photomultiplier base.
3. Simona is unable to test the gains for the pion detector PMTs that were used in the Mainz beam tests until August when NPS installation is done, unless we can come up with an urgent reason to do so. Do we have one, or can we simply rely on our measurement of PEs from the widths of the amplitude spectra?
4. Some initial discussions of counting mode trigger options for pion and shower-max detectors.