July 20, 2011 Tracking CDC/FDC

Meeting Time and Place

Wednesday July 20, 2011 at 11:00am At Jefferson Lab, the meeting will be held in F326

Connections

To connect from the outside, please use ESNET

1. ) ESNET: 8542553
   
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Agenda

1. Announcements
2. FDC Update logbook
3. CDC Update
   1. Construction Progress
   2. Professional photos of layer 22 photos
   3. Update on the electrical hookup prototype photos
   4. FADC Update

Minutes

Participants: Curtis, Naomi, Beni, Eugene, Mark, Simon, Dave, Tim

FDC Update

1. There are some problems with wire planes 1 and 2 not holding HV and the currents of the sense wires are far too high (micro Amps).

Initially it was thought that washing the wire plane #1 with water and alcohol to clean off the solder flux might be the cause. But when plane number 2 showed similar issues and has not seen any water other causes were sought after. It was finally found that some of the capacitors are drawing far too much currents and the reason is residual flux underneath these capacitors. The current procedure is now to test every capacitor individually on each wire frame and redo the once that draw too much current thereby cleaning any flux very careful. This in mind the wire frame production that was on halt has now continued again.

1. While the wire frame/stringing was on hold cathode production was continuing. Now 8 cathode planes are ready.

1. So far 8 cathode planes and 3 wire are frames ready, however the stacking of these frames is delayed until the wire deadening

of the central region of the wires can be done. This procedure is waiting for the necessary chemicals to arrive.

1. Simon is looking at the tracking efficiency and resolution when the last FDC frame is moved slightly upstream by 20cm. This would minimize the gap in photon reconstruction.

CDC Update

1. Straw installation - the last stereo row (24) is nearly complete.
2. Tension tests - 6 broken wires were found in the 6 strung layers (and will be replaced during the next stringing session). All the wires did pass continuity testing soon after stringing; the tension measurements were made several weeks afterwards. The wires all broke in or near to the crimp pin. We plan to remeasure the tension in the other wires.
3. A few of the CDC photos taken by CMU's photographer are on line.[CDC photos]
4. The wire hookup prototype is finished and is being used for wiring practice. [PCB hookup prototype]
5. Naomi made a slight improvement to the prototype CDC resolution by improving the timing by sending the logic signals from scintillator discriminators and coincidence into the fADC.
6. Tim has sent out the cheeseplate spec to some vendors for comment prior to bidding. Labelling every hole will be cost-prohibitive so this might be reduced to 10% of the holes. We will have to accept stock material (polycarbonate), Tim will double-check that clear polycarbonate was specified.