Difference between revisions of "Minutes-7-11-2013"

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= Minutes =
 
= Minutes =
  
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Participants: Bill, Dave, Chris, Nick, Simon, Vlad, Beni, Eugene, and Lubomir.
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Participants: Bill, Dave, Chris, Nick, Vlad, Beni, Eugene, and Lubomir.
 
== Production ==
 
== Production ==
  
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- Bill: two spacers are ready, the last one will be glued right after the meeting. Pictures of the spacers, the fixture and the gluing are attached above. The carbon fiber rods are glued to the g10 cylinder. The two gusset rings needed for this procedure were taken from the spare package which is sitting now on a granite table with two Lexan sheets on both sides. Tomorrow after the last spacer is ready, we will put the gussets back. This operation requires at least 4 people, since we use metal pins inserted in the six places when lifting the Lexan sheets. As in happened already when taking the gusset ring in the same way, the pin can lift some of the planes/cells up.    
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- Final package installation (see the pictures linked above): First Casey found a tiny hole in a cooling tube and he successfully fixed it with solder. We tried to check the cooling system for leakages using CO2 at 100psi, but the leak detector was not sensitive at all to CO2 even when you have obvious leakage. The first two packages were put on the installation cart and the spacer between them installed. The spacer fits tightly on the gusset ring and it was especially difficult to insert it in the second package. For the next spacer Bill proposed to make several holes, so that one can pull and make the circular shape at the end of the spacer in order to insert it into the gusset. We also had to do several cuts at the end to make space for the fiducial holders.  
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- Lubomir and Vlad showed some results from the thick cell study with a scope. We used two differential probes connected to wires from the two top cells. We used a scope as a trigger and fADC: we triggered on coincidences from the two wires, thus selecting almost vertical MIP that crossed the whole volume above the wires. We recorded manually about a thousand events and the plots linked above represent the results from their analysis. We increased the HV to +2450/-500V which corresponds to about 2-3*10^5 and it was stable for the whole weekend. With such high gain and very low noise (threshold of 5mV) we were able to see individual electrons with about 80% efficiency. There was 30-40 % loss of electrons (somehow different for the two cells) due to recombination (oxygen was 90-100 ppm) over the very long drift time of >20usec. Increasing the flow will reduce this effect. One can see the correlation in the cluster number counted by the two cells. The width of the difference agrees with the statistics. Interesting studies of the amplitudes of the single electrons
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show a nice exponential distribution of the gas gain with a slope that agrees to the average gas gain.  
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== Engineering ==
 
== Engineering ==

Revision as of 18:41, 11 July 2013

July 11, 2013 FDC meeting

Agenda

  1. Production
  2. Engineering (Bill)
  3. Electronics (Chris, Nick)
  4. Full electronics test FDC E-log (Beni)
    • Pre-amp contact issues (Vlad)
  5. Thick cell results [8],[9],[10], [11](Lubomir, Vlad)
  6. Other


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