Minutes-11-3-2011

November 3, 2011 FDC meeting

Agenda

1. Production Construction Tracking (Dave)
   • Clean room status
   • Production update
   • First package tests (Lubomir)
2. Engineering update (Bill)
3. Electronics update (?)
4. Testing set-up at EEL126 (Beni)
5. TDR (Lubomir)
6. Other

Minutes

Participants: Bill, Dave, Vladimir, Beni, Mark, and Lubomir.

Production

- Dave on production (see the link above for details): Six cathodes for package#2 ready. Scanning of wire positions: the hardware problem we have with the controller (ADC from the sensor gives numbers in 2V range instead of 10V) was "fixed" by reducing the threshold to 1.8V in the software. Surprisingly now we almost never miss wires; before we had ~10% of filed wires missed. Still, Dave will write a report about the problem that will be sent to Parker (with Larry's help) till the controller is still has warranty. Unfortunately, it may take several weeks to fix the problem and we don't want to do this now.

- Dave: yesterday we lost one phase at Blue Crab that affected the HVAC system for 2 hours. The particle counts went up to 41,000, but then dropped down to standard (~400) in few hours after the power came back. Bill suspects some dust accumulated in the returned ducks went into the clean room. Ron Bartek is aware of the problem. Fortunately only HVAC was affected and we could finish the electroplating that started before the outage, but we decided to install UPS system to be used for such critical operations. Mark offered a UPS and help to install it at Blue Crab. The UPS will be installed outside the clean room with extension cords going inside.

- Lubomir: After we found the noise on the top cell of the first package originating from two places on the wire frame (+HV traces on the back of the PCBs) we looked more carefully at the same places in the other cells. Similar noise was found on another two cells but with smaller amplitude and frequency. We found the frequency of the noise (and interestingly also the dark current) depends somehow on the pressure you apply on the PCB in this area by the torque on the nearby threated rod. Likely explanation is that we have some sparking between the HV traces and the rochacell due to possible scratches or de-lamination of the trace (Bill). In any case the frequency is no more than few hundred Hz which is not a problem.

Engineering

- Discussing without Bill the protective covers: aluminum 1/8" thick. Eugene asked why they are so thick so we can't use iron source. Lubomir: we didn't require the possibility to use a source, but actually when testing the package it will be very easy to remove the top cover and do tests with a source. Dave had a concern that the covers are too heavy and may cut the plastic rods, but it turned out that there will be plastic inserts that will cover the rods.

Electronics

- Chris: set-up is ready to start testing the first 22 pre-amps manually. It will take several days but Chris will not be at JLab next week. We will look if some of our techs, or Vladimir can do the tests. Chris wanted to know if we can have also additional brackets for the spare pre-amps.

Chamber testing at 126

- Beni: need to make 36 twisted pair ribbon cables to be connected between the translator boards and the F1TDCs. Chris will look for the cables and connectors. The production of the translator boards is in the procurement. We should check on this later.

TDR

- There's "Tracking" section before the CDC and FDC detectors that Simon will look into it. However, mainly we will concentrate on the FDC description as a detector. After the meeting Lubomir, Simon, and Eugene discussed the FDC section in more details.

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