December 22,2010 Tracking CDC/FDC

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Meeting Time and Place

Wednesday December 22, 2010 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
2.) Phone:
+1-800-377-8846 : US
+1-888-276-7715 : Canada
+1-302-709-8424 : International
then enter participant code: 77438230# (remember the "#")

Agenda

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

Minutes

Participants: Curtis, Naomi, Eugene, Beni, Mark, and Lubomir.

FDC Update

Lubomir reported on FDC construction:

  • Three weeks delay with the clean room construction, will be ready end of January.
  • After cleaning, all the PCBs that were tested so far (more than half) hold the required 2500V.
  • First article cathode foils were inspected: generally they meet the requirements, still we have some remarks to the vendor.

Lubomir presented gas gain measurements and Garfield calculations for several Ar/CO2/CH4 mixtures. The addition of 5% methane reduces significantly the afterpulses. If these cause some problems, like increasing the event size (Beni), we may consider using CH4.

CDC Update

Curtis gave an update on the construction status:

  • The spec for the electrical hookups is undergoing discussion.
  • The 7th row of straws is nearly complete. The 8th row will be started after the holiday break and will complete that block of stereo straws. Curtis is to be trained in straw fitting training this afternoon as a contingency worker because installing the straws requires 3 people working together. (In fact Curtis and Naomi both did this). It takes about 1.5h to install 30 straws. Most of the other steps in the construction just require 1 person at a time. The feedthru insertion process was slow at first as some of the parts were too tight but this is now proceeding smoothly.
  • The plastic feedthrus and donuts have been checked with 100% acceptance. About half of the pin-holders have been checked; all but one (which was squashed) have been accepted. The accepted parts have been cleaned and are in storage in the cleanroom.
  • After the first batch of straws, no more resistance issues have been encountered. The resistance of each straw (+donut+feedthru) assembly glued into the chamber has been acceptable.
  • We are waiting to hear a date for delivery of the next batch of straws.

Naomi reported that after some hardware issues she had got the new fADC working through CODA. New fADC The earliest hits in a track are in ~ sample 40 (320ns) so the buffer time ahead of the trigger will need to be increased to enable the pedestal to be fitted ahead of the event pulse. Switching back to the old ADCs somehow upset the (ageing) logic electronics and the new fADC setup is taking a break for the holidays (aka not working). [LATER: Fixed with replacement of another intermittently bad ecl cable].