Minutes of the forward endcap EMC eZuce SRN meeting, 18th of December 2017, 14:00-14:45
Presence:
Basel: excused
Bochum: Cathrina, Claudius, Fritz-Herbert, Malte, Matthias, Miriam, Tobias T., Tom
Bonn: Christoph
Groningen: -
Stockholm: -
Uppsala: Pawel
Giessen: Hans, Markus
GSI: -
Results from Cosmics tests stand measurements:
The two 'model units' (made with preamps of known gain) have been measured in the Bonn test stand
Cosmics peaks of 220 MeV show up at about 118 mV which would result in an equivalent maximum energy at the preamp output maximum of 2.2 V of about 10 GeV (including 40% gain loss of the VPTTs in the Panda solenoid B-Field)
That would mean the preamps have too much gain and we cannot detect the maximum of 12 GeV per crystal
Need to recheck measurement...
Production Readiness Report II (APD subunit manufacturing):
There was the second PRR for the Forward Endcap concerning APD subunit manufacturing with emphasis on the APD screening (a topic marked as being critical)
We presented an alternative to the PSL screening that we demonstrated on 90 APDs screened in Bochum, irradiated in Giessen, rescreened in Bochum and annealed and rescreened again in Bochum
We concluded that there is no need to bias the APDs during irradiation, that we need 48 hours of annealing time (at 80 degrees C), that we need to take DC characterisitic curves only and that we restrict to two temperatures (+20, -25 degrees C)
There have been visits to the PSL lab as well as to Strahlenzentrum Giessen