April 24, 2013 Tracking CDC/FDC

Meeting Time and Place

Wednesday April 24, 2013 at 11:00am At Jefferson Lab, the meeting will be held in F326

Connections

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Hardware Agenda

1. Announcement
2. FDC Update
3. CDC Update CDC_odd_events

Minutes

Present: Curtis, Naomi, Beni, Simon, Lubomir

1. FDC Update
2. CDC Update
   1. Naomi reported on the CDC channel testing - so far 113 boards have been used for reading out data with HV of 2100 or 2200V, 50/50 Ar/CO2. Normally we would use 2.1kV but are going to 2.2kV now in order to save time later on if we should need to exceed 2.1kV.
   2. Only 2 sets of 3 transition boards have had trouble in reaching 2kV, all the others went to 2.2kV without a hitch. The trip setting used was 0.8uA total for 3 or 4 boards (72-96 straws). We will revisit the less cooperative boards and use a trip setting of 8uA if necessary. The boards usually draw very little current from the HV supply, 8nA or less for 3 boards is typical.
   3. Naomi has documented some unusual CDC events on the page CDC_odd_events. There are some more normal events shown on CDC_events. On page CDC_odd_events the top sets of events show pickup in strawless channels from huge hits on the straws, the pickup is about 1/10 x the amplitude of the hit signals; the lower sets of plots show some events where all 72 channels were subject to huge oscillations starting at the cosmic ray's arrival time. This was not seen on a subsequent run using the same straws. Apart from that one noisy run, this occurs in less than 1% of events.
   4. The daisy-chain LV supply cable for the preamps is starting to fall apart, 2 wires broke so far, Beni is going to look for some more cables and/or minibridge connectors.
   5. Lubomir will talk to Slava about finding drawings for the HV mounting blocks for the FDC in the hope that these can be copied for the CDC.
3. fADC125 Update
   1. Beni heard from Cody that he has almost finished testing 30 fadcs - he still has to do the full crate tests - and hopes to be able to send some to CMU by the end of next week.