Difference between revisions of "Minutes-8-7-2014"

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# CDC status (Mike, Beni)
 
# CDC status (Mike, Beni)
 
#* [http://www.jlab.org/Hall-D/detector/CDC/noise/test4 noise studies]
 
#* [http://www.jlab.org/Hall-D/detector/CDC/noise/test4 noise studies]
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# FDC status [http://www.jlab.org/Hall-D/detector/fdc/DAQ/FDC_inter_cluster_tracking.pdf](Lubomir)
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# FDC status [http://www.jlab.org/Hall-D/detector/fdc/DAQ/FDC_inter_cluster_tracking.pdf interaction event reconstructed with cluster timing algorithm](Lubomir)
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
 
# Engineering  
 
# Engineering  
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= Minutes =
 
= Minutes =
  
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Participants: Sean (NU), Curtis (CMU), Eugene, Luke, Mike, Sergey, Dave, Chris, Nick, Simon, Beni, and Lubomir (JLab).
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Participants: Sean (NU), Bill, Luke, Mike, Chris, Nick, Simon, Beni, Eugene, and Lubomir (JLab).
  
 
== DAQ ==
 
== DAQ ==
  
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- Beni showed several results, explained in the logbook linked above. There are some fADC channels that don't report valid data (log entry 3290451). There's one module (ROCFDC3 slot 4) that was OK at the beginning of the run but at some point (after ~1k events) started reporting this problem for all of the channels.
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- Beni: the synchronized run (CDC +BCAL) didn't work over the weekend. Something is wrong with the data, as if the the signals were not in the time window. Still, the DAQ was running over the weekend without crushing. Will try it again this weekend.  
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- Typical CDC and FDC signals (from fADC) are shown in entry 3290447. The noise in the CDC is a factor of 2 higher than in the FDC (entries 3290447 and 3290445), also interestingly the frequency of the correlated noise in the CDC is a factor of 2 bigger. Lubomir: the CDC boards have 1/2 divider of the input signal, in contrast to the FDC. Would be interesting to check the noise without these resistors using also an FDC pre-amp.
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+
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- Beni found that there's some instability of the pedestals (3290411). For some of the channels there's even oscillation (3290403) with a period of about one hour.
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- The plan is to have a synchronized (CDC&FDC + BCAL) run over the weekend.
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== CDC update ==
 
== CDC update ==
  
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- Mike showed his studies of the noise (linked above). The burst noise (200kHz burst with 25MHz noise) disappears when turning off the HV of all/most of the channels. The other (white) noise doesn't depend on the HV. Mike showed possible sources of noise with a clock closer to 25MHz. For the FDC noise within the bursts is 12.5MHz.
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- Beni: the noise was studied with modified HVB in which the resistors, that reduce the signal by 1/2, were removed. As result, both the noise and the signals increased by factor of 2. Beni will try also with the FDC pre-amp.
  
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- Noise discussions - Eugene: you should try with the cell repeater turned off. Beni: install some kind  of copper mesh to shield the whole front of the CDC; the old FDC cathodes can be used for that? Sergey: try to shield the pre-amps with a box around them; some kind of pre-amp shield was already tried.   
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- Beni and Mike tried to improve the ground using: grounding braid connected to one HVB, Al foil covering the whole magnet opening. No improvements so far, but maybe one has to ground many more HVBs before you see any effect (Beni).   
 
   
 
   
 
== FDC update ==
 
== FDC update ==
  
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- Lubomir: pictures attached show how the track through all the chambers was fitted: first using only cathodes fitting the avalanche positions (first plot). The residuals vs drift time (converted to distance) are correlated (second plot). Applying drift time corrections with already known (from the first fit) direction results in a line fit with chi^2/21 = 17/21 assuming 1mm error. If exclude the points for which the hits are very close to the wires, or at the edge of the cell, we get chi^2/14 = 6/14 which means resolution is about 650 microns.
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- Lubomir was improving the tracking: significant advantage if one uses the timing of each ionization cluster. It should be the same for the  
  
 
== Electronics ==
 
== Electronics ==

Revision as of 16:48, 7 August 2014

August 7, 2014 FDC+CDC meeting

Agenda

  1. DAQ (Beni)
  2. CDC status (Mike, Beni)
  3. FDC status interaction event reconstructed with cluster timing algorithm(Lubomir)
  4. Electronics (Chris, Nick)
  5. Engineering
    • Chiller
    • Cathode scan [1] (Luke)
  6. Commissioning/calibration discussions (all)
  7. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653


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