Minutes-8-14-2014

August 14, 2014 FDC+CDC meeting

Agenda

1. DAQ (Beni)
2. CDC status (Mike, Beni)
   • noise studies no ground,with ground
3. FDC status (Lubomir)
4. Electronics (Chris, Nick)
5. Engineering (Bill)
   • Chiller
   • Cathode scan [1] (Luke)
6. Commissioning Wiki Page, FDC commissioning plan (all)
7. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653

Minutes

Participants: Curtis, Naomi(CMU), Sean (NU), Bill, Luke, Mike, Chris, Simon, Beni, Fernando and Lubomir (JLab).

CDC update

- Beni installed a wide grounding braid connecting in a chain all HV boards in one sector (#4). The pictures above demonstrate significant improvement. The 200kHz noise from the HV power supply is gone and the random noise is down by >25%. Only this one HV channel was turned on.

- Fernando contacted CAEN concerning the 200kHz noise coming from 1550 and interestingly even more from 1535 module. The noise goes through the HV return lines connected to the aluminum ring at the front of the CDC and this ring needs to be grounded first. Further we should think of a better, non-destructive way (4 pre-amp cards were somewhat damaged) of installing ground there.

- It's not clear exactly how the grounding helped, but it worked only after connecting all of the cards from this sector. It might be the stand-offs that connect the cards to ground have some resistance? (Bill). The HVBs have LV vias on the back side, so one should find a better place for connection, but that's possible (Fernando).