Difference between revisions of "Minutes-1-29-2015"

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== Collaboration meeting agenda ==
 
== Collaboration meeting agenda ==
  
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- In addition to the allocated talks, Vlad needs 10 min for "FDC gain calibration". Eugene: this is a tracking session and should be devoted to tracking and calibrations, f125 stuff can go to the electronics, but there's no electronics sessions? To be discussed next time again.
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- the agenda seams to be finalized (see link above).
  
 
== Gas puzzle ==
 
== Gas puzzle ==
  
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- Lubomir investigated the effects of the alcohol in the gas using Garfield. Experimental results (first plot) from the FTD detector at HERA show increase of the drift velocity with the increase of the ethanol in their Ar/propane mixture. Garfield simulations (next two plots) describe this results well enough. Contrary, adding 1-propanol in our gas mixtures of Ar/CO2 makes the gas slower, and surprisingly increases the gain significantly - 70% if adding just 1% (absolute) alcohol. Thus, a mixture of 54/45/1 Ar/CO2/propanol explains (next two plots) both, the CDC time-to-distance and the increase by a factor of ~4 of the gain compared to the 50/50 mixture. It's difficult to estimate the propanol percentage during the last run. If using the vapor pressures and assuming equilibrium, it must be 0.2-0.5% ranging due to the temperature and pressure variations in the alcohol bubbler. If roughly estimate the alcohol consumptions it must be closer to 1%.
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- Vlad and Lubomir prepared a small setup for the CO2 measurements (pictures). The CO2 sensor was calibrated in the EEL126 with a certified gas mixture of Ar/CO2 with 59.66% CO2. Then we moved the setup to the hall and connected it at the same place where the oxygen sensor is supposed to be - right before the exhaust bubblers - where, using solenoid valves you can choose different chambers. We did short measurements with the CDC and the first FDC package - the results (including calibration) are summarized in the linked ppt file: CDC has 41.4%, FDC has 55.3% CO2 +/-0.3% RMS. The CDC measurements showed some variations but monitoring over longer period of time is needed.
  
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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.
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- Right after these measurements, the software could no longer recognize the sensor and we were not able to do more measurements. Lubomir is contacting now the company to resolve the problem. We had also another issue with the plastic cup on the top of the sensor that had holes drilled in a wrong place, but Scot fixed it.  
  
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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 from cosmics. Naomi will do also measurements with the JLab electronics.
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- Noami did measurements with the prototype at CMU for 
  
 
== FDC update ==
 
== FDC update ==

Revision as of 18:37, 29 January 2015

January 29, 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
  5. Electronics (Fernando, Cody)
    • CDC status (Nick, Chris)
  6. Engineering (Dave)
  7. Other


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