Minutes of the forward endcap EMC eZuce SRN meeting, 24th of October 2016, 14:00-15:15

Presence:

• Basel: Werner
• Bochum: Cathrina, Claudius, Fritz-Herbert, Malte, Tobias H., Tobias T., Tom
• Bonn: Christoph, Matthias, Merlin
• Groningen: Myroslav
• Stockholm: -
• Uppsala: -
• GSI: -

Glueing:

• "Primer glued" APD equipped crystal has been running temperature cycles for weeks, read out ratio unchanged 1:1, mechanical stability tests by hand passed - stopped cyling with this crystal and put two new units for same tests into fridge
• "Primer glued" radiation hard glass pieces: Giessen transmission measurements show just a few percent of transparency loss below 350 nm
• Giessen irradiation of "primer glued" radiation hard glass pieces: Visually no deterioration of coupling or transparency, transmission curve to be measured (in the meantime this has been done: within measurement uncertainties no irradiation effects observable!)
• Comparison of more "Giessen-like" glueing procedure: Glueing three APDs "with pressure" (1 kg weight apllied) and three APDs without results in comparable strong coupled APDs - there is about the same torque necessary to break the couplings
• However, the resulting glue film thickness is much thinner when preassure is applied during curing of the glue

Preamps:

• Inconsistency in determination of necessary APD preamp gain: latest Bonn cosmics test stand measurement and Bonn beam time data do not fit
• Malte and Tobias H. will further investigate the problem
• 100 more VPTT preamps to be connected to spare tubes ordered - production hopefully before end of the year

ADC boards:

• Resistors in the shaping input stages need to be changed in order to adopt for correct input range with different shaping times (done in the meantime)
• If done, waveform sampling for different shaping time channels will be done (done in the meantime)
• Also planned: pile-up studies w/ CAEN detector emulator
• Myroslav suggested to keep the ADC board in Bochum in order to get the measurements running rather than send it to KVI for irradiation. Irradiation should instead be done on a different board (has to be clarified w/ Pawel - done by Malte later on)
• (As the board currently located in Bochum is the one that has been neutron irradiated at TSL it is actually preferred to also irradiate this one with protons at KVI in order to learn about cummulative irradiation effects...)

ADC crates:

• Is it possible to already produce ADC crates according to the latest drawings?
• Is it necessary to design the backplate PCB before (Pawel) and see if everything fits?