Difference between revisions of "Minutes-10-22-2015"

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(Created page with "October 15, 2015 Drift Chamber meeting = Connection = # [https://halldweb.jlab.org/wiki/index.php/Connect_to_Bluejeans_Meetings Instructions for Bluejeans meeting connection...")
 
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October 15, 2015 Drift Chamber meeting
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October 22, 2015 Drift Chamber meeting
  
 
= Connection =
 
= Connection =
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# Electronics (Fernando, Chris, Nick)
 
# Electronics (Fernando, Chris, Nick)
 
# Engineering (Dave)
 
# Engineering (Dave)
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#* gas pressure variations [http://www.jlab.org/Hall-D/detector/fdc/gas_system/press_temp_corr.png], [http://www.jlab.org/Hall-D/detector/fdc/gas_system/press_temp_corr2.png]
 
# Other
 
# Other
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= Minutes =
 
= Minutes =
  
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Participants: Naomi, Mike (CMU), Eugene, Fernando, Luke, Marc McMullen, Brian Eng, Beni, Dave, Chris, Nick, Simon, and Lubomir (JLab).
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Participants: Naomi, Mike (CMU), Sean (NU), Fernando, Luke, Dave, Chris, Nick, Simon, and Lubomir (JLab).
  
 
== CDC update ==
 
== CDC update ==
  
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- Simon is working on parametrization of the tube deformations and discussed with Naomi details. At least for the B-field corrections you don't need different maps, can just scale from one table.
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- Simon submitted changes reflecting the time-to-distance calculations. He uses Mike's table with the wire-tube offsets (as extracted with cosmics) to re-calculate the time-to-distance function (with field off and on), as he reported last week. Mike is checking the new calculations for curved tracks.
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- Lubomir used Garfield to study the ion-tails in CDC using the electronics response function as measured by Naomi. From certain distance to the wire center, 20 to 60 microns (plots attached), we start one electron and one ion and calculate the signals induced on the wire. For distances < say 30 microns the ion contribution (green) is compatible with the electron one (yellow) and there's an ion tail at ~10% of the peak. For bigger distances the tail is canceled by the electron contribution due to the tail-cancellation part of the response function. This means if the avalanche develops closer to the wire we see ion-tails.
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- It is not clear why we see such tails mostly in the CDC (scope pictures shown before by Fernando and Lubomir for cosmics and with 55Fe source), could be the electronics is little different (divider at the pre-amp input in CDC), or the detectors are different, though around the wire the field is the same.
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- Noami showed a link (see above) with her studies of the effect of the ion-tails and ways of integrating the signals. Tails are seen for the big signals. One needs first to study the effect of the tails on the position and dE/dx resolution and then decide if we want to optimize the tail cancellation for the CDC.
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== FDC update ==
 
== FDC update ==
  
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- Lubomir linked an abstract to be submitted to VCI2016 conference.
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- Lubomir almost finished converting his code with specialized FDC alignment/efficiency calculations into a plugin that runs with the standard halld analyzer. One important difference is that the multi-hit feature present in the original code could not be preserved in the pluging - halld analyzer assumes only one hit per channel. Still the resolutions obtained with the plugin are very similar to those with the original code. Some tweaks had to be made in the emulation code, as well. The plugin produces 3D hits (points) using both cathode (amplitude) and wire (timing) information. We will work on an interface that passes these points to Simon's tracking.  
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== Electronics ==
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- Fernando will compare the electronic response for the CDC and FDC on the bench.
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- Fernando used a generator to put signals at the front of the pre-amps and didn't see the reflections (reported before by Lubomir) over the 18m cable. Will repeat the measurement with a non-terminated adapter card.  
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== Engineering ==
 
== Engineering ==
  
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- The FDC chiller was replaced successfully with the new one (just to use the warranty). The only difference now is the Fluorinert flow is lower than before, ~13.6 LPM compared to ~14.8 LPM before. In both chillers this was causing alarm, for that we needed to set the low limit to 0, the other possible value for this parameter is 15 LPM.  
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- Dave: the NBX serial issue is still there, even he tried to to put all kind of possible software fixes. Next step would be to replace the hardware - the NBX module and the MFC control box.
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- Dave set the pressure in the FDC mixing tank to vary between 10.8 and 12 psi (as discussed on the last meeting). No changes for the CDC mixing tank.
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- Dave will fix the NBX serial issue in the gas system tomorrow; gas system will be stopped for a while.
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- Lubomir showed plots with correlation b/n the variations in the temperature in one of the BCAL crates (up to +/-4degC) and the FDC pressure (+/- 1Pa). These oscillations started over the weekend, when the humidity went below 30% the HVAC system stopped regulating it, but only the temperature.

Latest revision as of 15:38, 22 October 2015

October 22, 2015 Drift Chamber meeting

Connection

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

Agenda

  1. CDC update (Mike, Simon)
  2. FDC update (Luke, Lubomir)
  3. Electronics (Fernando, Chris, Nick)
  4. Engineering (Dave)
    • gas pressure variations [2], [3]
  5. Other

Minutes

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

CDC update

- Simon submitted changes reflecting the time-to-distance calculations. He uses Mike's table with the wire-tube offsets (as extracted with cosmics) to re-calculate the time-to-distance function (with field off and on), as he reported last week. Mike is checking the new calculations for curved tracks.

FDC update

- Lubomir almost finished converting his code with specialized FDC alignment/efficiency calculations into a plugin that runs with the standard halld analyzer. One important difference is that the multi-hit feature present in the original code could not be preserved in the pluging - halld analyzer assumes only one hit per channel. Still the resolutions obtained with the plugin are very similar to those with the original code. Some tweaks had to be made in the emulation code, as well. The plugin produces 3D hits (points) using both cathode (amplitude) and wire (timing) information. We will work on an interface that passes these points to Simon's tracking.

Engineering

- Dave: the NBX serial issue is still there, even he tried to to put all kind of possible software fixes. Next step would be to replace the hardware - the NBX module and the MFC control box.

- Lubomir showed plots with correlation b/n the variations in the temperature in one of the BCAL crates (up to +/-4degC) and the FDC pressure (+/- 1Pa). These oscillations started over the weekend, when the humidity went below 30% the HVAC system stopped regulating it, but only the temperature.

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