Minutes of the forward endcap EMC eZuce SRN meeting, 1st of August 2016, 14:00-15:10

Presence:

• Basel: excused.
• Bochum: Cathrina, Malte, Matthias, Tobias T.
• Bonn: Merlin
• Giessen: -
• Groningen: Myroslav
• Stockholm: -
• Uppsala: -
• GSI: -

Preamps:

• The first batch of VPTT preamplifiers (160pcs.) have arrived in Bochum and we started assembling VPTT-preamp units!
• We also got a batch of 32 APD-preamps and will start producing a new APD-subunit

Glueing:

• We are stil investigating the "1:2" problem, using a crystal standing upright in one of our climate chambers, yet no clear picture evolved on whats the cause for the different signal yields.
• Up to now, all lost glue-couplings had in common, that the glue did not stick to the crystal. Thus, we are performing several additional glueing tests using pre-series PANDA-crystals (untapered) that we got from Giessen. These tests are also involving two different primer liquids from DowCorning.

SODANET:

• Myroslav reported on timing measurements he performed using two digitizers. He measured a time shift between the two boards of 30-50ps after letting it run for a complete weekend, though Myroslav is still checking the data.
• Additionally, Myrsolav measured the time difference in dependence of the temperature of an ADC board. For this purpose, he pre-warmed one board to ~70C and kept a second one cold. Then he switched the system on and measured the temperature as well as the time difference (normal working temperature of an ADC board is around 50C). The measured time difference increased from zero to 100ps after switching on the system.
• This behaviour will not be a problem for the EMC, but could be important for other subsystems which have a time resolution of better than 100ps.
• Myroslav wants to test for how much temperature variation we can allow and proposed to have look-up-tables for the FPGAs on the SODANET hubs containing values for the time difference at different temperatures to correct for the shift.

Miscellaneous:

• In Bochum we are investigating the options for feeding the cables for the low-voltage supply into the endcap inner volume. The current idea is, to have a common supply cable for 8 subunits and interconnect these 8 subunits to distribute the LV.
• The large aluminium sheets for the outer hull of the endcap have been manufactred; they will be delivered to another company for further processing (holes, etc.)
• We sent samples of different materials for the inner stiffener ring to Giessen for irradiation and received them back. Due to massive changes in color we can discard some of the materials and are left with one or two that might be usable. These samples need to be irradiated with a higher dose (~2000Gy) and will be sent to Giessen again.