Difference between revisions of "Minutes-7-3-2014"

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= Minutes =
 
= Minutes =
  
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Participants: Naomi (CMU), Curtis, Dave, Beni, Chris, Nick, Simon, Bill, Fernando, Eugene, and Lubomir (JLab).
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Participants: Naomi (CMU), Beni, Dave, Chris, Mike, Simon, Fernando, Eugene, Glenn, and Lubomir (JLab).
  
 
== Readiness review ==
 
== Readiness review ==
  
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- Curtis prepared (Elton requested) a draft of a commissioning plan for the CDC (linked above). Lubomir and Beni will do the same for the FDC. It doesn't have to be a final version. All the other documents needed for the review are ready.  
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- Drafts (very preliminary) for the CDC and FDC commissioning were prepared for the readiness review (page linked above). For the FDC the plan so far is to use two gas mixtures, 90/10 and 40/60, the first one is better for the alignment. The target position(s) and turning on/off the magnetic field needs to be coordinated.
  
 
== Gas system ==
 
== Gas system ==
  
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- On Wednesday Scott replaced quickly under pressure, the relief valves on the two mixing tanks (first picture). This morning he replaced also the too regulators outsides, because they had some silicon rubber inside, and installed two filters (for the CO2 and Ar lines) that will remove water and oil contaminations. Fernando was concerned about the silicon. Beni: it works with high rates (i.e. with beam), but we need to start bubbling with alcohol.
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- Last Friday, in the morning, the power in the gas room was turned off for ~15 min due to a planned electrical work there. After turning it ON, the setting in the gas control panel were wrong (40mA, while the range is 4-20mA). As a result: the flow was doubled and the PLS code didn't turned OFF the flow controllers when they reached
  
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- Scott had to stop the gas to the detectors this morning for about 4 hours and for this time the pressure in the CDC dropped almost to the atmospheric (~2-3Pa above). The fourth package dropped to about 39Pa (from 60Pa), all the other FDC packages didn't show significant changes in the pressure. Naomi proposed to look with a borescope camera at the downstream Mylar.
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- We started using the Oxygen sensor set-up. There was a small issue: the pressure sensor is supposed to stop the pump if the pressure goes below some limit to prevent under-pressure in the chambers. However, the gas is taken just next to the bubbler and the pressure there varies a lot. To avoid this Beni set the pump to run always, and Dave added in the PLS control to shut down all the valves to the Oxygen sensor if the pressure in any chamber goes below 30Pa.
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- We measured the Oxygen on Tuesday and Wednesday using the two sensors and (after some flushing) they gave more or less consistent results: CDC ~3-5ppm, FDC1 and FDC4 ~5-8ppm (extremely low values!). Bill is concerned that the sensors may need calibration. Beni: let's see first if we have problems (charge not constant with the drift time). Today Lubomir did measurements right after the gas was restored: CDC ~8ppm, FDC1 ~35ppm, FDC2 ~120ppm, FDC3 ~46ppm, and FDC4 ~25ppm. Very strangely, the chambers that had bigger leakage this morning showed smaller Oxygen contamination.
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== CDC noise ==
 
== CDC noise ==

Revision as of 16:36, 3 July 2014

July 3, 2014 FDC+CDC meeting

Agenda

  1. Commissioning plans
  2. Gas system
  3. DAQ (Beni)
  4. CDC status (Beni)
  5. FDC status (Lubomir)
  6. Electronics (Chris, Nick)
  7. Engineering (Bill)
  8. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653

Minutes

Participants: Naomi (CMU), Beni, Dave, Chris, Mike, Simon, Fernando, Eugene, Glenn, and Lubomir (JLab).

Readiness review

- Drafts (very preliminary) for the CDC and FDC commissioning were prepared for the readiness review (page linked above). For the FDC the plan so far is to use two gas mixtures, 90/10 and 40/60, the first one is better for the alignment. The target position(s) and turning on/off the magnetic field needs to be coordinated.

Gas system

- Last Friday, in the morning, the power in the gas room was turned off for ~15 min due to a planned electrical work there. After turning it ON, the setting in the gas control panel were wrong (40mA, while the range is 4-20mA). As a result: the flow was doubled and the PLS code didn't turned OFF the flow controllers when they reached


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