Radphi Video Conference 7/8/2003

July 8, 2003
University of Connecticut
Storrs, CT

Meeting Agenda:

1. Shower energy resolution in LGD - M. Kornicer
2. Nonlinearity correction in LGD - R. Jones
3. Radiation damage in LGD - D. Armstrong
4. Selection of figures, tables for NIM paper - discussion
5. Progress on PWA - D. Krop
6. Progress on BGV calibration - D. Steiner

• http://dustbunny.physics.indiana.edu/~teige/nim
• http://zeus.phys.uconn.edu/radphi/call-notes
• http://zeus.phys.uconn.edu/~kornicer/radphi/LGDresolution
• http://zeus.phys.uconn.edu/radphi/calibration/figs.html
• http://dustbunny.physics.indiana.edu/~dkrop/2pi
• http://www.physics.wm.edu/~steiner/radphi

Present: R. Jones, M. Kornicer, D. Steiner, D. Armstrong, S. Teige, D. Krop, D. Sober

• On the work reported in this note, Mihajlo has done a definitive study of the resolution of the LGD, both in shower energy and centroid. He was able to obtain clear sample of 2-cluster events that reconstruct to π° and η. For the η sample he found the signal was clean if he required at least 20cm of separation between the clusters. He formed mass plots for several selections of well defined energy pairs E1, E2 and measured the mass resolution. He interpreted this as a combination of shower energy and centroid resolution. He separated the two effects by using both η and π° samples in a global fit to a resolution function based on the known parametrization of lead-glass resolution. The overall fit is good, resulting in
  and
  
  • He showed a plot and table that will be included in the NIM article as measured LGD performance.
  R. Jones: Report on: MC study
  • he has done a study of the Monte Carlo shower generation, to compare with the latest findings from MK. He showed a number of plots that gave details on comparison. The resolution from MC
    
    compares well with real data for most of our energy range. He showed that the fit varies with θ from
    
    to
    
    with the above reflecting the average, and agreeing well with real data. Nonlinearities that are not presently treated correctly in the MC+reconstruction were shown to be small, so no readjustment + recalibration is planed.
  • There was some discussion of the mass walk seen in MK's TechNote plots. Two ideas will be tried to seek understanding
    1. generate and reconstruct MC η, π° > 2γ.
    2. see if a phenomenological gain-suppression at low energies might account for the walk.
    It was not clear whether this could be showed in time for the article. If not, we will simply note the presence of bias and say it is not explained as a nonlinearity in our MC.
  Dan Steiner: BGV calibration http://www.physics.wm.edu/~steiner/radphi/bgv_cal.htm"
  • He showed his progress on the above web site. His Ln(E_up/E_down) is not linear in Z as one would expect, leading to suspect either his (t_up -t_down) Z measurement or the reliability of the ADC value - threshold affects or pedestal. He will look into it. It is obvious that one and has much better resolution in t than the other. I suspect varying resolution can also produce such effect.
  Next meeting: Wednesday July 23, 2003, 8:30am

  ---

  This page is created by Mihajlo Kornicer