Minutes of the forward endcap EMC eZuce SRN meeting, 29th of August 2016, 14:00-15:15

Presence:

• Basel: Werner
• Bochum: Fritz-Herbert, Matthias, Tobias T., Tom
• Bonn: Christoph
• Giessen: Hans, Markus, Stefan, Rene
• Groningen: Myroslav
• Stockholm: Karoly, Markus
• Uppsala: Pawel
• GSI: -

APD Preamps:

• The performance of the new APD preamps is very satisfying. They work stable w/o oscillation tendencies and give low noise output signals.

Glueing:

• Several things discussed:
  • The 1:2 problem of differently responding APD channels on one crystal is obviously related to the glueing even though we do not exactly understand what is going on
  • Giessen glueing tests show loss of transparency of coupling w/ primer ('milky' look). Maybe they used too much primer - we will redo such glass on glass couplings
  • Usage of Dow Corning primers clearly improves adhesion of glue to crystals
  • Maybe the usage of vacuum to the glue before coupling harms the glueing process/strength of adhesion? GI does not 'apply vacuum' and they report to have no problems w/ fallen off detectors. We will compare both glueing methods for strength of coupling

ISEG HV modules:

• Tobias and Matthias reported about several problems with our ISEG modules (wrong HV readings, unstable zero load currents, full channel failures etc.)
• Some modules have been sent to ISEG and are fixed now - they charge about EUR 750,- for repair!
• The whole HV supply situation is not satisfying: We have regularly failing modules, all modules seem to need regular calibration or repair. Serious APD screening is heavily affected by this. It is unclear how to run a 10-years-experiment with such equipment.

SADC:

• Fritz-Herbert and Tobias flashed the Bonn software to one of the FPGAs on the board
• However, there seem to be hardware communication problems. Pawel mentioned a possibly broken link-status LED that may confuse people...
• Pawel will provide a special link test tool and asked whether the correct PLL frequency is set (need to be checked)
• Johannes will be able to come to Bochum next week if still needed