Difference between revisions of "Meeting-4-19-2018"

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# fADC125
 
# fADC125
 
# Other
 
# Other
 
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= Minutes =
 
= Minutes =
  
Participants: Sean(FSU), Eugene, Beni, Simon, Alex A., Alex B., Sergey, and Lubomir (JLab).
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Participants: Naomi(CMU), Eugene, Simon, Alex B., Sergey, and Lubomir (JLab).
  
 
= CDC  =
 
= CDC  =
  
- Sergey showed an updated version of his report about the CDC background studies. It includes plots of the hit occupancy as function of the beam current with physics trigger and pulser (random) for inner and outer rings. While the two curves (physics and random) are parallel for the outer rings, at high occupancy as it is in the inner ring, this is not the case. There's no quantitative description yet. The plan is to take more data at higher intensities.
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-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.
  
- The phi-asymmetry in the inner CDC rings that Sergey found in case of no radiator and that is significantly suppressed when inserting W-foil (40 um) or emptying the target, can be explained by a synchrotron radiation from the vertically-bending magnet in the ramp to the tagger (Richard proposed this).  
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- 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.
  
- Naomi suggested looking in the phi-asymmetry of the pedestals, that may be coming from the same polarized synchrotron radiation.
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- 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.
  
 
= FDC =
 
= FDC =
  
- Similar noise that has been observed last spring appeared again on two FDC wire cards (connected to one TDC module). The noise is present only after starting the DAQ and disappears soon after you stop it. Beni suggested disconnecting both cables from the TDC when looking with a scope on one of them. This was done later, but no difference in the noise was found.
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- Sergey plans to do similar signal analysis for the FDC, as well.
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 +
= Tracking =
  
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- 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%.

Latest revision as of 18:16, 19 April 2018

April 19, 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 [2] [3]
  2. FDC update
  3. fADC125
  4. Other

Minutes

Participants: Naomi(CMU), Eugene, Simon, Alex B., Sergey, and Lubomir (JLab).

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.

- 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.

- 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.

FDC

- Sergey plans to do similar signal analysis for the FDC, as well.

Tracking

- 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%.