Update on Cherenkov M.Apollonio, Univ.of Trieste and INFN

1
Update on CherenkovM.Apollonio, Univ.of Trieste
and INFN

• remarks on calibration
• update on phase1 nt-uple analysis
• remarks on Monte Carlo
• conclusions

2
Calibration status

• may june calibration files have been completed
• need to be committed yet (next days)
• comment further files can be added in order to
  have a more refined calibration, but I consider
  2002 as done

3
Update on phase1 nt-uple examination

• attention focused on a series of runs done at
  low momentum (3 GeV/c) and with varying dipole
  current (18322?18329)
• an old exercise already done, but this time we
  can play with nt-uple1()
• use NDC to reconstruct tracks
• extrapolate the Cherenkov cone axis towards the
  PMTs plane
• match the reflected axis with the closest
  CkovHit
• study the correlation between
• number of photoelectrons seen by the Cherenkov
• Momentum as reconstructed by NDCs
• Ecal Energy
• 
  () thanks to Charles Pattison

4
Run Dipole Current
18322 2910
18323 1940
18324 970
18325 0
18326 -970
18327 -1940
18329 -2910
NDC track
Reflected ckov cone axis
5
Comparison NDC vs Ckov Hits
6
(No Transcript)
7
Selection of e-like events
8
run by run
9
(No Transcript)
10
(No Transcript)
11

• Oscillating pattern
• Basically due to PMT/Winston cones geometry
• In addition, PMT q.e.

12
Monte Carlo

• status at an early stage
• Purpose at the moment understanding geometrical
  properties (ray-trace)
• HdrCkovMcDigi.cpp for any step taken by the
  particle in the gas N50 rays are shot with an
  average angle qCKOV (if bgtbth)
• The rays are propagated and reflected as long as
  they reach the Cherenkov Mirror
• Their position on the PMT plane is recorded
• If different weights are assigned to different
  hit area (e.g. w1 for the PMT photocathode,
  w0.85 when a Winston cone is reached) one
  retrieves an oscillating pattern reminding the
  one observed in data
• Preliminary but promising

13
m
2 GeV/c
4 GeV/c
6 GeV/c
8 GeV/c
10 GeV/c
14
Conclusions

• Calibration for 2002 is OK
• Phase1 nt-uple analysis going on
• Work on MC started