August 4, 2010 Tracking CDC/FDC

Meeting Time and Place

Wednesday August 4, 2010 at 11:00am At Jefferson Lab, the meeting will be held in room F326-327

Connections

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Agenda

1. Announcements
2. FDC Update logbook
3. CDC Update
   1. Update on the new straws (Pictures).
      1. The scratches are gone.
      2. Acceptance rate has been 104 out of 108 straws. After cutting open the four rejects, we concluded that three also would have been acceptable. The one failure is a glueball on the straw (we are writing the paper now).
      3. The straws are much cleaner than anything we have seen before - just a few white spots - so we are looking modifying our cleaning procedure.
      4. Lamina told us the straws are manufactured in a clean room and any dust we see can only be mylar dust ( and we do not see very much at all).
      5. Lamina is going to do production with an interior carton so we can clear all the packing material away before opening the inner case.
   2. Our pneumatic glue injection supplier also supplies epoxies (Elsworth Adhesives). We have gotten a better price for our conducting epoxy from them. The glue is also sold in a better dispenser system -- basically a dual cartridge syringe with a very short mixing chamber. They also have a shorter (10 day) lead time than McMaster Carr. Cheaper price, less waste, quicker mixing.
   3. We have 50/50 AR-CO₂ premix.Premixed_50/50
   4. Update on noise studies with the new preamplifier (Caged prototype). Noise_studies
4. AOT

Minutes

• Discuss preamp: small scale CDC prototype was put into aluminum cage together with preamp card and temperature sensor power supply. Reduced noise to about 15mV peak to peak. Also connected HV ground to shaper card ground. Fernando is preparing a small sketch of the grounding scheme.
• FDC: position resolution of wires look good < 0.2mm! Oxygen contamination in the chamber is indeed about 0.1% as predicted by Lubomir looking at wire response vs drift time. The Oxygen was measured using our new oxygen sensor. Preliminary studies show that 90/10 Ar/CO2 might be a better operating mixture for the FDC. Further studies are needed. The current prototype is now operated with this gas mixture.
• CDC: the new straws from Lamina finally arrived at CMU. They look good. And pass inspection. Resistivity over the full length was measured to be 46 Ohm. Straw will be cut and looked at microscope shining light from the back. Lamina was contacted by Tim to give a go ahead for production and request information on time scale.