Meeting 1/27/22 - COMTRA

Eric's update cyrstals

- I am in contact with the Alpha-Spectra company which was providing BGO crystals for a local project we had in Orsay.

  This is a US company which provides crystals with a guaranteed 8-9% resolution. At the time we were investigating for
  an order they were less expensive than Saint-Gobain and turned-out to be more performant (we performed dedicated
  measurements to test this).

- They should be back to me shortly with information about availability of improved radiation hardness crystals as well

  as radiation limits of the crystals they are currently providing.

- It should be noted that litterature about radiation aging of BGO crystals indicates that after a rapid loss of about 20%

 of transmission, the performance is kind of stable. Some experiments chose to first irradiate crystals to operate in  that 
 regime.

- we may need tools to control the overall stability of the experimental signal... dedicated cosmic ray calibration run or

 light illumination... too early stage to provide a direction of answer, but this should be kept in mind.