Difference between revisions of "Minutes-4-9-2015"

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# Gas puzzle
 
# Gas puzzle
−
#* CO2 monitoring [http://www.jlab.org/Hall-D/detector/fdc/gas_system/co2_monitoring_04_02.pdf]
+
#* CO2 monitoring [http://www.jlab.org/Hall-D/detector/fdc/gas_system/co2_monitoring_04_09.pdf]
 
# CDC update (Beni, Mike)
 
# CDC update (Beni, Mike)
 
# FDC update (Lubomir)
 
# FDC update (Lubomir)
−
#* Alignment status [http://www.jlab.org/Hall-D/detector/fdc/spring2015runwire_res_comp_ell_hall.pdf]
+
#* Alignment status [http://www.jlab.org/Hall-D/detector/fdc/spring2015run/wire_res_comp_ell_hall.pdf]
 
# Electronics (Fernando, Cody, Chris, Nick)
 
# Electronics (Fernando, Cody, Chris, Nick)
 
# Engineering
 
# Engineering
 
# Other
 
# Other
−
 
+
#* [http://www.jlab.org/Hall-D/detector/fdc/TR/Spare_in_TAG.jpg TR test in tagger]
−
<!--
+
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Curtis, Naomi(CMU), Sean(NU), Eugene, Luke, Mike, Dave, Chris, Nick, Cody, Beni, Simon, and Lubomir (JLab).
+
Participants: Naomi(CMU), Sean(NU), Fernando, Luke, Mike, Dave, Chris, Nick, Cody, Beni, Simon, and Lubomir (JLab).
−
 
+
−
== Running at half energy ==
+
−
 
+
−
- For the FDC we expect to have about the same e.m. background on the chambers, i.e. we will be limited by the same photon intensity as in the fall run. The number of pion tracks is expected to be about half of that in the fall. We asked for 16 hours beam time assuming we will have 8 hours at each of the two HV settings: 2200V and 2250V. As the HV filter boxes are expected to reduce the noise significantly, we ask for 16h run only at one setting - 2200V but at a lower discriminator threshold - thus compensating for the smaller number of tracks.
+
  
 
== Gas puzzle ==
 
== Gas puzzle ==
  
−
- The new pump has been installed in the EEL and data taken with the spare package using the certified gas mixture. On the attached plot: CO2 measurements (blue), atmospheric pressure (black), corrected measurements (red) using (dp/p)^2.4 pressure correction. This pump has variable flow, Nick and Chris made voltage control for that. Thus the flow was adjusted in this way, keeping the rotameter open completely, so that the pump doesn't create vacuum.  
+
- The CO2 sensor was moved last Friday to the Hall connected to the CDC (figure attached above). Beni changed the CO2 gas factor from 0.74 to 1 on Sunday: the CO2 percentage started going down. On Tuesday Beni changed the gas factor to 0.5 (just a guess) then CO2 started going up in the right direction.
  
−
- The plan is to monitor the certified gas till Friday afternoon, then move the sensor to the Hall and monitor the CDC for one more day. On Saturday afternoon Beni will change the CO2 gas factor to 1.  
+
- Beni did several other tests: Ar gas factor set from 1.391 to 1 for a short period of time. Not clear yet what the problem is with the gas mixture.  
  
 
== CDC update ==
 
== CDC update ==
  
−
- Naomi found in run 2451, some of the pedestals are wobbling by 100+/-3 units on a scale of hours. Could be temperature variations, in any case it is small compared to the thresholds of ~60.
+
- There are many files collected with the BCAL cosmics trigger to be used for the CDC alignment. They are being analyzed now.
  
 
== FDC update ==
 
== FDC update ==
  
−
- The HV channel on FDC4 cell 6 sector 2p, developed a constant current of ~3 microamps (at the nominal 2200V) after being unstable for a week (current/voltage plots attached). Most likely the problem is outside of the gas volume and we may attempt to fix it sometimes when the FDC is pulled outside of the magnet. 
+
- Lubomir finished aligning the individual packages - there are 48 parameters per package, 8 per cell. Next step: use three packages for tracking and aligning the fourth as one piece. Using the outer packages for tracking, there's an improvement of the resolution compared to the resolution obtained by using the package itself (figure attached). The new resolution is very close to the one obtained in the EEL where the timing from the scintillators that are very close to the chamber, is the best.
−
 
+
−
- Interesting results with an 55Fe source shown on the plots: ratio of the upper strip to down strip charge as a function of the avalanche position along the wire used in the trigger for both tests, with the spare package and with FDC4 in the Hall. Apart from variations along the wire caused by some differences in the gains of the strips and position w.r.t. center of the strip, there are two images 10% apart. Beni proposed these are avalanches above and below the wire, but the avalanches develop so close to the wire that is difficult to explain the 10% difference.
+
  
 
== Electronics ==
 
== Electronics ==
  
−
- The HV filter boxes will arrive next week and will be installed right away.  
+
- The HV filter boxes have arrived.  
  
−
== Engineering ==
+
- Nick and Chris will help with the spare package cabling and installation of the fADCs, HV and LV modules, as instructed by Fernando.
  
−
- We discussed if we can monitor spikes/glitches in the power, since we suspect some of the HV trips are related to that. Dave has such monitoring for the magnet, but needs to be put into the EPICS stream.
+
== Other ==
  
−
-->
+
- The FDC spare package was moved to the Tagger successfully (picture attached). It will be used to test it as a transition radiation detector.

Latest revision as of 18:15, 14 April 2015

April 9, 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. Gas puzzle
    • CO2 monitoring [2]
  2. CDC update (Beni, Mike)
  3. FDC update (Lubomir)
    • Alignment status [3]
  4. Electronics (Fernando, Cody, Chris, Nick)
  5. Engineering
  6. Other

Minutes

Participants: Naomi(CMU), Sean(NU), Fernando, Luke, Mike, Dave, Chris, Nick, Cody, Beni, Simon, and Lubomir (JLab).

Gas puzzle

- The CO2 sensor was moved last Friday to the Hall connected to the CDC (figure attached above). Beni changed the CO2 gas factor from 0.74 to 1 on Sunday: the CO2 percentage started going down. On Tuesday Beni changed the gas factor to 0.5 (just a guess) then CO2 started going up in the right direction.

- Beni did several other tests: Ar gas factor set from 1.391 to 1 for a short period of time. Not clear yet what the problem is with the gas mixture.

CDC update

- There are many files collected with the BCAL cosmics trigger to be used for the CDC alignment. They are being analyzed now.

FDC update

- Lubomir finished aligning the individual packages - there are 48 parameters per package, 8 per cell. Next step: use three packages for tracking and aligning the fourth as one piece. Using the outer packages for tracking, there's an improvement of the resolution compared to the resolution obtained by using the package itself (figure attached). The new resolution is very close to the one obtained in the EEL where the timing from the scintillators that are very close to the chamber, is the best.

Electronics

- The HV filter boxes have arrived.

- Nick and Chris will help with the spare package cabling and installation of the fADCs, HV and LV modules, as instructed by Fernando.

Other

- The FDC spare package was moved to the Tagger successfully (picture attached). It will be used to test it as a transition radiation detector.

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