Difference between revisions of "Minutes-7-31-2014"

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FDC meeting ID: 290664653
 
FDC meeting ID: 290664653
 
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= Minutes =
 
= Minutes =
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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.
 
- 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.
  
- 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 CDC (entries 3290447 and 3290445)
+
- 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 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.
  
== CDC update ==
+
- 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.
  
- Beni studied the CDC noise once again (all the results are linked above): using a scope on one channel (#4 connector C6) with a stand alone DC power. He made measurements in different conditions: turning on/off LV/HV the power for the crates itself and also ramping the HV. He was looking for is 60Hz noise and 200kHz bursts with tens of MHz within the bursts. The conclusion: the 60Hz comes when powering the south HV supply (connected to the card). The 200kHz bursts come when rumping up the HV and stay when the HV is up.
+
- The plan is to have a synchronized (CDC+FDC & BCAL) run over the weekend.  
Fernando wanted more tests with more cards and HV modules to see if this is a problem with a particular module/HV crate or a common feature of this CAEN system.
+
  
- Mike found that for the "problematic" channels (with no signals in the fADC but visible on the scope) one can actually see something (noise or signal) in the fADC but with a huge DAQ offset of 0xd000. It is not clear yet what is the quality of the signals.  
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== CDC update ==
 +
 
 +
- Mike showed his studies of the noise (linked above).
 
   
 
   
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== FDC update ==
 
== FDC update ==
  

Revision as of 16:40, 31 July 2014

July 31, 2014 FDC+CDC meeting

Agenda

  1. DAQ (Beni)
    • Pedestals FDC and CDC pedestals as a function of time
  2. CDC status (Mike, Beni)
  3. FDC status [1], [2], [3], [4] (Lubomir)
  4. Electronics (Chris, Nick)
  5. Cathode scan (Luke)
  6. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653

Minutes

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

DAQ

- 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.

- 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 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.

- 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.

- The plan is to have a synchronized (CDC+FDC & BCAL) run over the weekend.

CDC update

- Mike showed his studies of the noise (linked above).