Pion Meeting May 10 2023 1:00PM ET

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

Attendance

Sudip, Elham, David, Wouter, Carl

Minutes

1. (David) Still no PMT test results yet from Simona.
2. (Elham) Discussion of possible PMT choices: https://dilbert.physics.wm.edu/Pion+Detector/107
   1. (David) We probably can't use borosilicate windows, due to thermal neutron interactions in boron (n, alpha). For a reference on this, see: U. Akgun et al., 2010 JINST 5 P08005
   2. (Wouter) Let's ask Neven to estimate thermal neutron flux at pion detectors using Fluka.
   3. (Carl) UV transparent glass is a borosilicate! We need to see what boron content is; maybe is still OK, otherwise we need to go to quartz windows, and many of the possible PMTs don't have this as a catalog option.
   4. (David post meeting): typically it seems that UVT glass material is Corning 9741 (https://www.freepatentsonline.com/4792535.html) which is 15-18% B_2O_3; compare with Corning 7056 borosilicate glass which is 17%, as far as I can tell).
   5. Can be a bit bigger than 1" diameter, but must fit in the cavity on the Pb donut
   6. (David) Don't need a fast PMT - we are not doing precise timing coincidences; the FADC250 with which we read out the trigger scintillators and the pion detectors has 4 ns wide time bins, so having much faster than this is not useful. Transit time in tube is not relevant in our application. Don't need high gain in either integrating mode (where we will only use reduced number of dynodes) or counting mode (where the custom base will have an amplifier). Note: the main detectors and showerMax have selected the ET 9305KB (but with quartz window -= special order?)
   7. (David) ET 9125QB seems like a good option to me; another option might be to see if we can get a quartz option for the 9111B series.
3. (David) Will get budgetary estimates from ET and Hammamatsu.
4. (Wouter) Should we order lucite now? Should we do whole batch or enough for new prototypes?
5. (David) We need to define the exact lucite dimensions (to ensure that detector will fit in the donut cavity, including the mechanical enclosure), but we don't know that yet. This is next top priority, to get those dimensions fixed.
6. (Carl, Wouter) will send David contact information for lucite suppliers.
7. (general) Typically, the vendor will use diamond milling to cut and polish the UVT lucite, which they may have purchased in sheets/slabs from a supplier, instead of being cast from a mold.