Difference between revisions of "Minutes-1-22-2015"

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- At least the CO2 content will be known soon. We have received a CO2 sensor (0-100% range) that is based on UV light absorption by the CO2 molecule. Needs calibration, will use a certified Ar/CO2 bottle ~40/60, and pure CO2.
 
- At least the CO2 content will be known soon. We have received a CO2 sensor (0-100% range) that is based on UV light absorption by the CO2 molecule. Needs calibration, will use a certified Ar/CO2 bottle ~40/60, and pure CO2.
  
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- Naomi showed her latest results (linked above) from CMU using the prototype.  
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- Naomi showed her latest results (linked above) from CMU using the prototype. She used 50/50 55/45 and 60/40 Ar/CO2 gas mixtures. There's an big increase in the gain between 55/45 and 60/40 but not that much between 50/50 and 55/45, If compared with the JLab results with no filed the mixture must be between 55/45 and 60/40 if there's no alcohol. Also the JLab results correspond to tracks at much smaller angles as compared to the almost perpendicular cosmic muons, which should also be corrected for.  
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== CDC update ==
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- Mike presented a report linked above: he and Simon found a parameter in the time-based track reconstruction that was not set correctly. After fixing this the efficiency is much higher (in the >90s% region). Great result! The residuals vs drift time has an offset ~300microns at >100ns which is interpreted as an indication for a different (faster) gas mixture. Note: the results presented are with magnetic field and the tracking was done with time-to-distance as simulated with Garfield for that field. Next step: to extract the time-to-distance from the data. Mike also presented the tool he made for reading/viewing one crate of f125s using pulser.
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- CDC efficiency to be discussed on the next meeting.  
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== FDC update ==
 
== FDC update ==
  
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- Vlad used Mike's tool to test the bad FDC channels (see logbook entry). Out of 8 channels, 7 could not see the pulser signal (applied at the input of the pre-amp), i.e. having issues with the pre-amp, cable, connector or the fADC. Chris and Nick will check the 3M connectors for these channels.
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- Vlad showed some studies of the systematics of the gain calibration procedure, comparing results using all the hits, and only those that are part of reconstructed tracks for the fourth package. The are statistically very similar. The channels with correction coefficient >1 (assumed to be "bad") show some differences (up to 50%) when using the two methods.  
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- From the alcohol consumption (~0.4l/30days for FDC and ~0.6l/30days for the CDC according to Scot) Lubomir estimated ~0.8% alcohol in the FDC and ~0.4% for the CDC, very crude estimate!!! From the vapor pressure estimations we get the same order of 0.5-1% alcohol. Since the pressure in the alcohol bubbler varies between 7-12psi the alcohol percentage would vary too. As a quick fix we will make the pressure range smaller.
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- Lubomir simulated with Garfield the effect of adding 1% propanol to the standard gas of 40/60 Ar/CO2. From the attached plots one can see ~6% decrease in the drift velocity, i.e. opposite to the effect observed in the data. If this is true we would expect much bigger deviation from the standard 40/60 Ar/CO2 mixture than what was estimated from the drift velocity to be 46/54 (see January 8 meeting), i.e. should be about 50/50! We are looking now for a way to measure the gas percentages in the mixture.
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== Electronics ==
 
== Electronics ==

Revision as of 19:40, 23 January 2015

January 22, 2015 FDC+CDC meeting

Connection

  1. Instructions for Bluejeans meeting connection
  2. FDC meeting ID: 290664653
  3. To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.

Agenda

  1. Collaboration meeting agenda
  2. Gas puzzle
  3. CDC update (Mike)
  4. FDC update
    • Gain calibration (Vlad)
  5. Electronics (Fernando, Cody)
    • HVB refurbishment (Nick, Chris)
  6. Engineering (Dave)
  7. Other
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