Difference between revisions of "Minutes-3-10-2016"

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February 25, 2016 Drift Chamber meeting
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March 10, 2016 Drift Chamber meeting
  
 
= Connection =
 
= Connection =
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#* [http://egbert.phys.cmu.edu/login new CDC ShareLaTex repository]  
 
#* [http://egbert.phys.cmu.edu/login new CDC ShareLaTex repository]  
 
#* svn ls https://halldsvn.jlab.org/repos/trunk/publications/GlueXFDC
 
#* svn ls https://halldsvn.jlab.org/repos/trunk/publications/GlueXFDC
 +
#* [http://www.jlab.org/Hall-D/detector/fdc/reports/LPentchev_vci2016_paper.pdf VCI contribution]
 
# Detector Status
 
# Detector Status
 
#* CDC update (Beni/Mike)
 
#* CDC update (Beni/Mike)
 
#* FDC update (Lubomir)
 
#* FDC update (Lubomir)
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#**
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#**[http://www.jlab.org/Hall-D/detector/fdc/hv_issues/FDC_currents.png FDC currents with empty target]
 
# Electronics (Fernando, Chris, Nick)
 
# Electronics (Fernando, Chris, Nick)
 
# fADC125 meeting (Naomi, Cody, Beni)
 
# fADC125 meeting (Naomi, Cody, Beni)
 
# Other
 
# Other
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−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
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Participants: Curtis, Naomi, Mike (CMU) Luke, Beni, Chris, Cody, Simon, Nick, Sergey, and Lubomir (JLab).
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Participants: Naomi, Mike (CMU) Eugene, Luke, Beni, Chris, Simon, Nick, and Lubomir (JLab).
  
  
 
== NIM papers ==
 
== NIM papers ==
  
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- As Naomi proposed for the CDC paper: Beni will write the Introduction and the Conclusions. Naomi, Mike,Simon will work out everything in between. Curtis will proofread the paper. Naomi wants to use the "old" svn system working on one file (section) at a time without interfering with somebody else.
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- Beni started working on the Introduction and Conclusion for the CDC paper.
  
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- Lubomir is working on the VCI contribution (4 pages in NIM) to be submitted by middle of March.
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- Lubomir is finalizing the 4-page NIM paper (attached) - a contribution to the VCI conference.  
  
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== Run Status ==
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== Detector Status ==
  
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- Beni: the HV channel in CDC that was problematic is now OK. The corresponding cards are oriented horizontally and are also at the top side, so most likely some kind of "dust" falls on them causing this problem.  
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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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- We see a factor of 4-5 higher currents now (both in the FDC and the CDC) compared to spring 2015 - see log entry linked above. We had half the energy at that time, but that's not likely enough to explain the difference. To understand the origin of the background we want to have measurements with empty target. We had it once but there are problems with the archiver for that period: the target status had wrong timing stamp.
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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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+
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- Two FDC HV channels (same cell4- hv4 for both, package 2 and 3) show strange behavior: they are OK as long as there's no beam, but with beam we see current jumps (plot attached) up to 5 uA for both positive and negative HV. This indicates that something is going on inside the gas volume, somehow triggered by the beam.
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+
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- Lubomir studied the average amplitude as a function of the drift time for two run periods - fall 2014 and spring 2015 (plot linked above). There's a drop of 30% for both periods. The current data is being analyzed. The plan is also to look at the data from the full test of the third package in the EEL126, but it will take some time to adjust the software for that. Mike will do the same analysis for the CDC.
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== fADC125 firmware ==
 
== fADC125 firmware ==
  
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Naomi added this:
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From Naomi:
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Cody put some more timing constraints into the firmware and and compiled it into a new version 2.09.  He and Beni tested it in the hall on Tuesday and Naomi revived the prototype setup at CMU and tested it there, this works but it is slow (only 24 channels, and slow data transfer off the computer).  Beni and Cody found that the duplicate sample words in the long readout mode are still present.  However, most of the errors in the calculated quantities due to timing problems have been corrected.  Naomi found 0 errors in leading edge times from 547060 hits.  There are a few logic issues in the peak search and possibly also a timing issue.  We will discuss this further and try again.  One of the peak search issues occurred when there were several samples of value 0 before the peak, because Naomi did not set the pedestals well.
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-->
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Cody is working on eliminating the timing errors from the firmware.  Naomi
 +
has been testing the new versions using the prototype at CMU.  A few
 +
differences in methodology have been straightened out but the timing
 +
errors are still being worked on.  Beni said that it should be possible to
 +
use the Hall D crates next week.

Latest revision as of 17:39, 15 March 2016

March 10, 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
  3. Electronics (Fernando, Chris, Nick)
  4. fADC125 meeting (Naomi, Cody, Beni)
  5. Other

Minutes

Participants: Naomi, Mike (CMU) Eugene, Luke, Beni, Chris, Simon, Nick, and Lubomir (JLab).


NIM papers

- Beni started working on the Introduction and Conclusion for the CDC paper.

- Lubomir is finalizing the 4-page NIM paper (attached) - a contribution to the VCI conference.

Detector Status

- 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.

- 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.

fADC125 firmware

From Naomi:

Cody is working on eliminating the timing errors from the firmware. Naomi has been testing the new versions using the prototype at CMU. A few differences in methodology have been straightened out but the timing errors are still being worked on. Beni said that it should be possible to use the Hall D crates next week.

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