Minutes-10-20-2011

October 20, 2011 FDC meeting

Agenda

1. Production Construction Tracking
   • Status (Dave)
   • First package tests (Lubomir)
   • Resistance of z-axis conductive tape (Lubomir)
2. Engineering (Bill)
   • Cooling/grounding system
   • Other: protective covers, new hubs, ...
3. Electronics update (Chris)
4. Testing set-up at EEL126 (Beni)
5. Other

Minutes

Participants: Eugene, Bill, Tim, Beni, Mark, Vladimir, Chris, Dave, Glen, Simon, Casey, and Lubomir.

Production

- Dave: Working on second package. First end window ready, second will be ready by the end of the day. Two cathodes (type-1) are ready. Another two cathodes (type-2 and 3) just need the daughter cards to be put on (the last operation). The first wire frame was strung and taped, but there were some delays with the position measurements. Wire scanning stops in the middle of the chamber, most likely due to a combination of software and hardware issues. Will try to find the Caleb's original software (Parker ACR project) and use it, at the same time to identify why it stops, which is the signal causing this.

- Lubomir: Vladimir tested all the channels from cell#4 top cathode to the top of the package. All channels are working. The exception is a noise seen on two channels, one on the bottom cathode and one on the top cathode of cell#6. Some smaller noise is seen also on their neighbors, mots likely induced from them. The noise looks like discharge, a sharp random signals (~10-20ns from the pre-amp) with amplitudes ~100-200mV and frequency ~1kHz depending on the HV. Vladimir checked carefully but couldn't find similar noise on any wire. The top and bottom strip showing noise do not cross each other. The noise appears only if there's HV on sector #4 for the top strip and on sector #2 for the bottom strip. In both cases the beginning of the strips and their traces leading to the connector are very close to the HV distribution chain on the PCBs for the corresponding sector.

- To investigate the noise problem, cell#6 was disassembled. Using a new card (made by Anatoly) now we can measure the resistance between the strip and the corresponding pin on the daughter card. We found that these noisy strips have higher resistance than normal: ~10 Ohms, compared to 1.5~4 Ohms.