Difference between revisions of "Minutes-3-24-2016"

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= Minutes =
 
= Minutes =
  
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Participants: Mike (CMU) Luke, Beni, Eugene, Simon, Nick, and Lubomir (JLab).
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Participants: Mike (CMU) Luke, Beni, Eugene, Simon, Nick, David L. and Lubomir (JLab).
  
  
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- Attached is the submitted  contribution to the VCI conference.  
 
- Attached is the submitted  contribution to the VCI conference.  
  
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== Detector Status ==
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== Detector and firmware status ==
  
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- Beni looked at the connector that was showing problems before (I22 at the lower outer side of the CDC), but couldn't find anything suspicious. Right now there are no problems with these channels. Beni set the CDC HV to 500V during the accelerator down time.  
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- Beni: no HV trips in the CDC even when the gas was Argon reach (when the CO2 switch-over didn't work). Testing with Cody latest version of the firmware which in addition to some fixes, has the option for PBIT parameter to be negative.
  
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- Lubomir discussed the measurements with empty target (chart attached). When the target was emptied the currents in the central FDC channels went down from 0.6 to 0.2 uA. After 20 min. we removed the profiler (and the TPOL converter) and when the beam came back the currents went up to 0.4 uA. Plotted is also the current in the corrector magnet and it also shows some change (possibly due to the effect of the profiler?) but it is not convincing that this caused the change in the FDC current. Eugene suggested another explanation: the profiler is stopping some low energy photons that are otherwise producing high currents in the FDC. These hypotheses have to be checked with empty target again by inserting the profiler and turning off the slow feedback.  
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- For the first part of the run FDC had threshold for sparsification of 120 for all the channels, with TH=100 and TL=25. Since then we tried individual thresholds of 7 and 5 sigma the widths of the pedestal, that however have to be bigger than TH which was set to 50 and 40. The problem is that TH is the same for all the channels in the module and it has to be lower than any  sparsification threshold. Lubomir is studying the effect of the TH/TL on the resolution of the timing algorithm. This is done by comparing the time from the wire TDCs and the leading edge time from the firmware for the corresponding strip signal. Results will be presented on the next meeting.
  
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== fADC125 firmware ==
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== Other ==
  
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From Naomi:
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- David for the open house: it would be good to have the spare package on the platform, will give people an idea what's inside the magnet. The downstream side will be closed with aluminum cup, we may leave the upstream opened or have a transparent cover.
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Cody is working on eliminating the timing errors from the firmware. Naomi
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has been testing the new versions using the prototype at CMU.  A few
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differences in methodology have been straightened out but the timing
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errors are still being worked on. Beni said that it should be possible to
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use the Hall D crates next week.
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Revision as of 17:27, 25 March 2016

March 24, 2016 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. NIM Papers
  2. Detector Status
    • CDC update (Beni/Mike)
    • FDC update (Lubomir)
  3. Electronics (Fernando, Chris, Nick)
  4. fADC125 meeting (Naomi, Cody, Beni)
  5. Other


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