Difference between revisions of "Minutes-10-15-2015"

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# CDC update (Mike, Simon)
 
# CDC update (Mike, Simon)
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#* [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_20microns.pdf 20mu],  
+
#* Ion tails for avalanches at [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_20microns.pdf 20mu], [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_30microns.pdf 30mu], [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_40microns.pdf 40mu], [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_50microns.pdf 50mu], [http://www.jlab.org/Hall-D/detector/fdc/garfield/signals_60microns.pdf 60mu]
 +
#* [https://halldweb.jlab.org/wiki/index.php/CDC_prototype_fADC_data Link to Naomi's studies].
 
# FDC update (Luke, Lubomir)
 
# FDC update (Luke, Lubomir)
 +
#* abstract to instrumentation conference [http://www.jlab.org/Hall-D/detector/fdc/LPentchev_VIC2016.pdf VCI]
 
# Electronics (Fernando, Chris, Nick)
 
# Electronics (Fernando, Chris, Nick)
 
# Engineering (Dave)
 
# Engineering (Dave)
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Curtis, Naomi, Mike (CMU), Luke, Beni, Dave, Chris, Nick, Simon, Sergey and Lubomir (JLab).
+
Participants: Naomi, Mike (CMU), Eugene, Fernando, Luke, Marc McMullen, Brian Eng, Beni, Dave, Chris, Nick, Simon, and Lubomir (JLab).
−
 
+
−
== Collaboration meeting ==
+
−
 
+
−
- Sergey was included in the tracking/drift chamber session with a talk about the Transition Radiation Detector.
+
  
 
== CDC update ==
 
== CDC update ==
  
−
- Simon showed new plots on the CDC tube deformation (elog linked). In addition to the last meeting results, now he has plots for positive/negative delta(phi) and most interestingly their sum and difference.
+
- 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.  
−
The sum looks very uniform indicating that the tube radius is OK and also that the wires are at the right positions.
+
−
This is not the case for the difference, which means the wires are not in the center of the tube. We conclude the tubes are deformed resulting in up to 2mm offset of the tube center w.r.t. the wire.
+
 
   
 
   
−
- Mike is working on the same studies but using cosmics. While Simon's beam result see the asymmetry in phi direction, the cosmic result would indicate asymmetry in horizontal direction. It is important to study also the z-dependence.
+
- 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.
 +
 
 +
- 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.
 +
 
 +
- 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.
  
 
== FDC update ==
 
== FDC update ==
  
−
- Cody and Sergey were able to run the new firmware with 1000-samples window on the right side of the tagger crate with the spare package. First plot above shows the signals (from bottom to top) from the first chamber wires, first chamber cathodes, and second chamber cathodes, when using 90Sr source; a second cell wire used for triggering. The max drift time (>8usec) looks bigger than expected from Garfield ~5 usec. This indicates different gas mixture (nominally 90/10 Ar/CO2) or weaker fields. Second plot shows a result with 55Fe source: total charge on x vs width of the signal in time (on y), the later estimated by the (total charge)/(max amplitude). The widening of the signal is explained by the diffusion at big drift distances which effect is amplified by the increased drift time. Nevertheless, when projecting on the x-axis one can clearly see the Ar peak and the escape peak (the structure at smaller charges).
+
- Lubomir linked an abstract to be submitted to VCI2016 conference.
  
−
== Engineering ==
+
== Electronics ==
  
−
- There are two independent problems with the FDC MFCs in the hall as explained in the log entry above. First related to the reading of the MFCs by the PLC as explained by Dave: the PLC sends reading requests for each MFC channel separately, but the data comes from a different channel. Dave fixed this issue. The other problem is that the MFC of the first package stops regulating the flow set for 200ccpm when the input pressure goes below 10 psi. According to Beni, the MFCs have been calibrated for 500 ccpm at 10 psi and thsi should never happen.
+
- Fernando will compare the electronic response for the CDC and FDC on the bench.
−
+
 
−
== Other ==
+
- 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.  
 +
 
 +
== Engineering ==
  
−
- No meeting next week, all the rooms occupied by EIC activities.
+
- 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.  
  
−
- Dave: Tina Mann, who worked very successfully on the FDC (especially cathode) production is leaving JLab soon.
+
- 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.
  
−
-->
+
- Dave will fix the NBX serial issue in the gas system tomorrow; gas system will be stopped for a while.

Latest revision as of 09:34, 16 October 2015

October 15, 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)
    • abstract to instrumentation conference VCI
  3. Electronics (Fernando, Chris, Nick)
  4. Engineering (Dave)
  5. Other

Minutes

Participants: Naomi, Mike (CMU), Eugene, Fernando, Luke, Marc McMullen, Brian Eng, Beni, Dave, Chris, Nick, Simon, and Lubomir (JLab).

CDC update

- 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.

- 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.

- 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.

- 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.

FDC update

- Lubomir linked an abstract to be submitted to VCI2016 conference.

Electronics

- Fernando will compare the electronic response for the CDC and FDC on the bench.

- 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.

Engineering

- 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.

- 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.

- Dave will fix the NBX serial issue in the gas system tomorrow; gas system will be stopped for a while.

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