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May 1, 2014 FDC+CDC meeting


  1. Gas system status [1],[2]
  2. DAQ trigger scintillators (Beni)
  3. CDC testing (Mike)
  4. Engineering (Bill)
  5. Electronics (Chris, Nick)
  6. Experimental Safety Assessment Document HallD_ESAD (Lubomir, Beni)
  7. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653


Participants: Curtis, Naomi (CMU), Bill, Dave, Beni, Chris, Nick, Simon, Mike, and Lubomir (JLab).

Gas system

- Pressure tests were done with industrial gas end of last week. The pure gas will come beginning of next week, then we can flush the whole system. However, we can start using the gas only after the ODH review is signed. ODH analyses show that, to have ODH-0 in the gas room, we need orifices of 0.052" on both Ar and CO2 input lines outside of the room.

- At the moment in the gas system we have only particle filters with 20 micron holes. Bill looked at possible gas filters for water, oxygen and hydrocarbons. The Matheson gas purifiers (first link) clean the gas down to 1ppm level. At CMU they used for the CDC less expensive filters (second link). Probably we need something in between and Bill is going to look into this.

- Gas filtration in the other halls: In Hall A they have expensive filtration but their gas volume is lower. In Hall B (according to Steve Christo) they have water and oxygen filters. There is no gas filtration in Hall C according to Brad Sawatzky. Generally people think that the pure gas as supplied doesn't require additional filtering, however you need filters to save the detectors in case the gas in the bottles is contaminated by mistake. We decided we can start using the gas system as it is, but we will implement additional filtration as soon as possible.


- Beni: for the FDC trigger, vertical scintillator planes were installed at both ends of the magnet (picture attached). Beni brought NIM electronics to make the trigger as a coincidence between the two planes. Beni has compiled the DAQ code (both for the FDC and CDC) to be used with external trigger.

CDC status

- Using the mini-DAQ readout with only the LV on, Mike started looking at the pedestals and working with Nick to identify and fix the problems. In the moment 10 pre-amps/cables/connectors require some fixing.


- The results from the last survey, we got from Jim Dahlberg so far, refer only to the FDC and CDC centers, using the survey results on the floor and assuming the detectors are rigid. Apart from the z-shift downstream of about 7mm, the other numbers are useless at least for the FDC where we want to know the positions and angles of each package separately. Another survey will be done in the fall.

- The mesh will be connected with a grounding cable attached at the middle top point. It may require additional grounding.


- Chris is going to look tomorrow once more with a scope on the bad 3M connectors, before attempting to fix them. The difference now is that he will be using a testing PCB without the 100 Ohm resistors on it.


- Beni is working on the gas system section.


- For the collaboration meeting we discussed what Beni is supposed to talk about the "Commissioning plans": target, trigger types, fADC125 requirements and modes of operation, amount of events etc.. We also discussed who will cover the fADC125 progress.