Difference between revisions of "Minutes-10-1-2015"

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# CDC update (Mike, Simon)
 
# CDC update (Mike, Simon)
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#* [http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2813 Fits to Garfield calculations for dealing with straw sag]  
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#* [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=2813 Fits to Garfield calculations for dealing with straw sag]  
 
#* [https://halldweb1.jlab.org/wiki/images/9/94/CDCUpdate1Oct2015.pdf Some sag measurements]
 
#* [https://halldweb1.jlab.org/wiki/images/9/94/CDCUpdate1Oct2015.pdf Some sag measurements]
 
# FDC update (Luke, Lubomir)
 
# FDC update (Luke, Lubomir)
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#* [http://www.jlab.org/Hall-D/detector/fdc/gas_system/MFC_p2_3_4_test.png MFC issues (cont.)][http://www.jlab.org/Hall-D/detector/fdc/gas_system/MFC_p1_2_3_4_plc_problem.png channel swapping],
 
#* [http://www.jlab.org/Hall-D/detector/fdc/gas_system/MFC_p2_3_4_test.png MFC issues (cont.)][http://www.jlab.org/Hall-D/detector/fdc/gas_system/MFC_p1_2_3_4_plc_problem.png channel swapping],
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
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== CDC update ==
 
== CDC update ==
  
−
- Simon presented a report (linked) about parametrization of the time-to-distance for different offsets (delta) of the wire from the center of the tube. The time-to-distance is fitted with a function which parameters depend on delta linearly.  
+
- Simon presented a report (linked) about parametrization of the time-to-distance for different offsets (delta) of the wire from the center of the tube. The time-to-distance is fitted with a function which parameters depend on delta linearly. This works for big times, for short he uses tables and a hybrid model in between. Maximum drift time (for a few tubes only) can be up to 2 microseconds.
−
+
 
−
- 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.
+
- Mike presented another report on studying the offsets with cosmics, offering better phi coverage than with beam tracks originating from the target. The results show mostly downward deformations of the tubes (sagging) at most 2mm with a few exceptions up to 3mm. The deformations are grouped in layers mostly for the stereo ones.  
  
 
== 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).
+
- Luke showed plots for the avalanche positions with 55Fe source, this time using the max amplitude instead of the integral. The results are very similar to the previous ones.
 +
 
 +
== Electronics ==
 +
 
 +
- Cody on the f125 firmware: introduced a hold-off if the buffer is full to avoid crushing in case several events come within short time. Will test it with Sergey. Now the max window size is 300 (?) samples, still can have a different version for special cases like the one for the TRD studies.    
  
 
== Engineering ==
 
== Engineering ==
  
−
- 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.
+
-Lubomir tested the FDC MFCs in the Hall. The MFC for the second package showed the similar problem as the first one (see last meeting) - it stops regulating the flow (set at 200ccpm) when the input pressure goes below ~8 psi (the first stopped regulating below 10 psi). Eugene suggested decreasing the variations of the pressure in the mixing tank from 7-12 to say 10.8 -12 psi. The last two MFC are OK. Beni wanted to have their serial numbers and look back - the MFCs were send for repair/recalibration at different times.
 
   
 
   
 
== Other ==
 
== Other ==
  
−
- No meeting next week, all the rooms occupied by EIC activities.
+
- No meeting next week due to the collaboration meeting.
−
 
+
−
- Dave: Tina Mann, who worked very successfully on the FDC (especially cathode) production is leaving JLab soon.
+
−
 
+
−
-->
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Latest revision as of 16:53, 24 February 2017

October 1, 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)
  5. Other

Minutes

Participants: Curtis, Naomi, Mike (CMU), Sean (NU), Simon, Luke, Eugene, Marc, Beni, Dave, Chris, Sergey, Cody and Lubomir (JLab).


CDC update

- Simon presented a report (linked) about parametrization of the time-to-distance for different offsets (delta) of the wire from the center of the tube. The time-to-distance is fitted with a function which parameters depend on delta linearly. This works for big times, for short he uses tables and a hybrid model in between. Maximum drift time (for a few tubes only) can be up to 2 microseconds.

- Mike presented another report on studying the offsets with cosmics, offering better phi coverage than with beam tracks originating from the target. The results show mostly downward deformations of the tubes (sagging) at most 2mm with a few exceptions up to 3mm. The deformations are grouped in layers mostly for the stereo ones.

FDC update

- Luke showed plots for the avalanche positions with 55Fe source, this time using the max amplitude instead of the integral. The results are very similar to the previous ones.

Electronics

- Cody on the f125 firmware: introduced a hold-off if the buffer is full to avoid crushing in case several events come within short time. Will test it with Sergey. Now the max window size is 300 (?) samples, still can have a different version for special cases like the one for the TRD studies.

Engineering

-Lubomir tested the FDC MFCs in the Hall. The MFC for the second package showed the similar problem as the first one (see last meeting) - it stops regulating the flow (set at 200ccpm) when the input pressure goes below ~8 psi (the first stopped regulating below 10 psi). Eugene suggested decreasing the variations of the pressure in the mixing tank from 7-12 to say 10.8 -12 psi. The last two MFC are OK. Beni wanted to have their serial numbers and look back - the MFCs were send for repair/recalibration at different times.

Other

- No meeting next week due to the collaboration meeting.

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