June 22, 2011 Tracking CDC/FDC

Meeting Time and Place

Wednesday June 22, 2011 at 11:00am At Jefferson Lab, the meeting will be held in F326

Connections

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Agenda

1. Announcements
2. FDC Update logbook
3. CDC Update

Minutes

Participants: Curtis, Naomi, Beni, Simon, Lubomir, Dave

FDC Update

1. The first package consisting of one chamber cell, was moved to JLab EEl1126 for testing with source and DAQ. It was bubbling at low flow rate of 50ccpm (Ar/CO2 90/10) but we had to increased it to 100ccpm, because the CO2 flaw controller is not sensitive at such low values. Surprisingly, it stopped bubbling at this higher rate and the differential pressure in the chamber increased from 30 to 45 Pa indicating some blockage in the exhaust pipe. Later we reduced the pressure down to ~30Pa and surprisingly again it started bubbling. We have also HV problems on one of the sectors.
2. The second chamber cell is ready and we will start installing the first detector package.
3. The techs are working on the third cell.
4. Beni fixed the DAQ in 126 and is working on the testing software.
5. There was a meeting at JLab on possible schemes for the FDC installation, cabling, and servicing. Even it was decided before that for servicing FDC will be moved downstream it is not clear how to feed the cables. It was decided to construct a mock-up and cable 1/4 of it.

CDC Update

1. The techs are part way through installing layer 22, the second layer of the last group of stereo tubes.
2. Six axial layers have been strung: 1,2,3,4, 13 and 14.
3. They have measured the tension of all the wires in rows 1,2,3 and 4 (192 out of the 438 strung so far). All except one wire was within specifications. The one which was out of specification will be replaced during the next stringing session, but it has now been removed from the chamber. Interestingly, this wire had passed the continuity measurement, but failed the tension measurement. It appears that either the crimp did not hold, or the crimp snapped the wire inside the crimp pin. When the wire was pulled, it was in one piece, and none was visible in the lower crimp pin.
4. The tension measurement process is fast and easy and the Helmholtz coils can be used for about an hour before they get too hot.
5. We had one day where the particulate count in the clean room soared to 57,000/cu.ft, this was associated with the extreme swampy weather conditions outdoors where the outdoor count was over 1,500,000/cu.ft. This count quickly returned to below 2000 after a thunderstorm and has remained low.
6. We also had the temperature and the humidity in the room rise to uncomfortable levels. After installing a dehumidifier and then an a/c unit the room became much more pleasant to work in. Conditions are all normal in the clean room now.
7. The HVB prototype that Fernando sent is fine. CDC prototype HVB
8. Naomi has been pursuing resolution measurements with Gerard's LE algorithm, varying the gas mix used in the Garfield time:distance lookup tables used for interpolation, so far 48/52 seems to be the best fit for mixed "50/50" Ar/CO2.