Difference between revisions of "Meeting-5-3-2018"

From GlueXWiki
Jump to: navigation, search
(fADC125)
 
(17 intermediate revisions by 4 users not shown)
Line 12: Line 12:
  
 
# CDC update
 
# CDC update
 +
#* [https://halldweb.jlab.org/DocDB/0036/003605/001/20180503_nacer_gluex_pid.pdf dE/dx truncation conclusion -- Nacer]
 
<!-- #* [https://logbooks.jlab.org/files/2018/04/3554679/CDC_2018_04_04.pdf Sergey's report] --->
 
<!-- #* [https://logbooks.jlab.org/files/2018/04/3554679/CDC_2018_04_04.pdf Sergey's report] --->
 
<!-- #* [http://www.jlab.org/Hall-D/detector/fdc/spring2018run/CDC_2018_04_05.pdf latest version of Sergey's report] -->
 
<!-- #* [http://www.jlab.org/Hall-D/detector/fdc/spring2018run/CDC_2018_04_05.pdf latest version of Sergey's report] -->
 +
#* [https://logbooks.jlab.org/entry/3570987 CDC efficiency over the run]
 +
#* [https://logbooks.jlab.org/entry/3571349 effect of W-foil on CDC hit efficiency]
 +
 +
{| border="0" cellpadding="2"
 +
|[[Image:cdc_eff_n.png|thumb|x200px|efficiency vs n, doca>0.35cm ]]
 +
|[[Image:cdc_eff_n_015.png|thumb|x200px|efficiency vs n, doca>0.15cm ]]
 +
|}
 +
 
# FDC update
 
# FDC update
<!-- [https://logbooks.jlab.org/entry/3562372] --->
+
#* [https://logbooks.jlab.org/entry/3563919 effect of W-foil on FDC current]
# fADC125
+
# NIM publications [https://halldweb.jlab.org/wiki/images/3/3c/GluexCDC_27apr2018.pdf CDC pdf] [https://halldsvn.jlab.org/repos/trunk/publications/GlueXCDC/ svn repository]
# NIM publications
+
 
# Other
 
# Other
 
<!--
 
  
 
= Minutes =
 
= Minutes =
  
Participants: Naomi(CMU), Eugene, Simon, Alex B., Sergey, and Lubomir (JLab).
+
Participants: Naomi(CMU), Nacer (GSI), Eugene, Simon, Alex A., Alex B., Beni, Cody, and Lubomir (JLab).
  
 
= CDC  =
 
= CDC  =
  
-Naomi showed plots with several noisy preams with some double-peak structures. Nick looked with a scope at these during the last access, but could not reach the preamp cards being behind the UFO shielding. However, it turned the second noise band disappeared after run 42188, which is when Nick was in the Hall, maybe it was a bad connection of the cable on the fADC.
+
- Naomi showed plots demonstrating CDC gradually deteriorates its performance during Dec. 2017 - May 2018 running. The efficiency drops at big drift distances significantly; at the same time time-to-distance remains almost unchanged (Alex B.). The most probable explanation is gas contamination. It is strange that the hit efficiency exhibits 30deg phi variation. We discussed also other than gas explanations - some features in the tracking, electronics, etc. The plan is first to fix the gas leakage and than look with cosmics (also before fixing and disconnecting cables).  
  
- We looked once more at the material scan. Sergey explained the results in more details looking not only at the "photons" but also at the other background signals. Their suppression is not as big as the one for the photons.
+
- Nacer finalized his studies of the dE/dx truncation (presentation attached). He simulated pions and protons and looked at the fraction of the misidentified protons for a fixed proton efficiency as a function of the momentum and angle. The minimum of this fraction is achieved for dE/dx truncation of 20-40%. A 20% truncation is used now in the analysis.  
  
- Changing the hole from 5 to 3.4mm resulted in a reduction of the FDC current (by ~35%), but the CDC current remained similar. Eugene's explanation is that since the current in the CDC comes from both synchrotron and bremsstrahlung, they compensated each other - synchrotron increased by a factor of 3 (beam current increase), while the bremsstrahlung was reduced due to the smaller hole.
+
- Beni showed the effect of the W-foil on the CDC per-ring hit multiplicity. It is reduced significantly both for random and physics trigger and also similarly for inner and outer rings, indicating higher energy photons are contributing.
  
 
= FDC =
 
= FDC =
  
- Sergey plans to do similar signal analysis for the FDC, as well.
+
- The FDC current dropped by ~25% after insertion of the W-foil at the entrance pipe, to be compared to 5% drop when the foil was directly at the front of the AC. Thus, we are considering installing the W-foil in the tagger.  
 +
 
 +
= NIM publications =
  
= Tracking =
+
- Naomi went over the current version of the CDC paper. Needs contributions from other people (svn link attached above).
  
- Sergey showed the effect of the filtering of the "photon" signals on the rho/omega yields as calculated by Simon. Combined with timing cuts, it improves the yields up to 60%.
+
= fADC125 =
  
--->
+
- Cody shared his plans for the summer and asked for an input what needs to be done. He has 10-20 spare modules that require some repair. ADCs can be fixed here, FPGAs by the company - require re-flow/re-ball $100-150/module - Eugene agreed. Work on the firmware - what should be the number of samples above threshold in the peak-finding algorithm (to avoid noise - to be discussed with Sergey), no need for high timing resolution after the first peak, implement the peak-finding procedure as it was used for the TRD studies, work on the self-triggering.

Latest revision as of 18:50, 3 May 2018

May 3, 2018 Drift Chamber meeting

Connection

  1. Instructions for Bluejeans meeting connection
  2. Meeting ID: 290664653

Headline text

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.

Agenda

  1. CDC update
efficiency vs n, doca>0.35cm
efficiency vs n, doca>0.15cm
  1. FDC update
  2. NIM publications CDC pdf svn repository
  3. Other

Minutes

Participants: Naomi(CMU), Nacer (GSI), Eugene, Simon, Alex A., Alex B., Beni, Cody, and Lubomir (JLab).

CDC

- Naomi showed plots demonstrating CDC gradually deteriorates its performance during Dec. 2017 - May 2018 running. The efficiency drops at big drift distances significantly; at the same time time-to-distance remains almost unchanged (Alex B.). The most probable explanation is gas contamination. It is strange that the hit efficiency exhibits 30deg phi variation. We discussed also other than gas explanations - some features in the tracking, electronics, etc. The plan is first to fix the gas leakage and than look with cosmics (also before fixing and disconnecting cables).

- Nacer finalized his studies of the dE/dx truncation (presentation attached). He simulated pions and protons and looked at the fraction of the misidentified protons for a fixed proton efficiency as a function of the momentum and angle. The minimum of this fraction is achieved for dE/dx truncation of 20-40%. A 20% truncation is used now in the analysis.

- Beni showed the effect of the W-foil on the CDC per-ring hit multiplicity. It is reduced significantly both for random and physics trigger and also similarly for inner and outer rings, indicating higher energy photons are contributing.

FDC

- The FDC current dropped by ~25% after insertion of the W-foil at the entrance pipe, to be compared to 5% drop when the foil was directly at the front of the AC. Thus, we are considering installing the W-foil in the tagger.

NIM publications

- Naomi went over the current version of the CDC paper. Needs contributions from other people (svn link attached above).

fADC125

- Cody shared his plans for the summer and asked for an input what needs to be done. He has 10-20 spare modules that require some repair. ADCs can be fixed here, FPGAs by the company - require re-flow/re-ball $100-150/module - Eugene agreed. Work on the firmware - what should be the number of samples above threshold in the peak-finding algorithm (to avoid noise - to be discussed with Sergey), no need for high timing resolution after the first peak, implement the peak-finding procedure as it was used for the TRD studies, work on the self-triggering.