Minutes of the Forward Endcap EMC SADC Crate Design Vibe/eZuce meeting, 9th of March 2020, 14:00-15:15
Presence:
Bochum: Tom, Matthias, Claudius, Fritz-Herbert, Malte, Marc, Jan, Tobias H., Sebastian
Basel: -
Bonn: -
Groningen: -
Uppsala: Pawel
Giessen: Markus, Hans-Georg
Space occupancy of VPTT submodules in FWEC:
VPTT Submodule dimension measurerments result in 2 mm longer modules compared to sclaes in CAD drawings
VPTT capsules are included in the CAD model and are therefore not the origin of the extra size
Interface pieces in the CAD drawings correspond to the real existing ones (that have been changed once the VPTT submodule capsules were introduced)
We need to measure the free space between front lid and backplate on the detector in Bochum in order to see whether there is a problem with submodule front cooling overlap
Recovery LED:
Concerning the latest measurements on LED introduced noise in the APD submodules Johannes showed single APD module channels where a 52.9 MHz oscillation is observed
Oscillation in APD readout channels is a clear sign of open preamp input, that is APD coupling loss. Malte looked up the oscillation frequency of open preamps measured years ago in Bochum lab: 44 MHz, which is quite close
After the meeting Tobias measured the oscillation frequency of an open input preamp of the latest version and could confirm the 53 MHz for the current version!
So we need the corresponding APD submodule back in Bochum in order to fix the broken APD - preamp coupling of that channel! (Once the module is brought to Bochum we will give in the order of 10 new modules to Bonn).
SADC crate power supplies:
The redesigned (still temporary) power supplies arrived
Efficiency is almost 90%
Input consumption of supplies is +/- 12 V, > 10 A - considerably more during power up
Pawel will send them to Bochum along with the SADC backplane PCB and some more SADCs