Central Pre-Shower status

1
Central Pre-Shower status

• Drew Alton
• University of Michigan

• CPS Status
• Hardware Plans
• Software Plans

2
Spatial resolution

• Resolution in f of 1.58 mr (MC expect 1.5 mr)
• Resolution in z of 3.2 mm (MC expect 2.5 mm)

3
EM Efficiency

• Efficiency of a good CPS cluster vs.
  discriminate for two samples
• Two em (standard cuts) objects each with a track
  match.
• This does have some background in it.
• JetEM events, with low MET and the Jet has low
  EMF.

CPS Discriminant
4
Calibration

• Pedestals stable over months, but not over ticks
• Expect to be more stable over ticks after
  shutdown
• MIP calibration is about as good as it will get.
• Appears to be good.
• Stable over 5 months

CFT Timing Change
RUN Number
5
Energy

• CPS isnt being used as part of EM energy yet
  because of saturation
• Below you see the saturation of the center strip
  and the cluster with respect to Cal Et.

6
MC Study

• MC Study on energy resolution
• Green shows the improvement using the CPS.

sE/E
7
Reconstruction version issues

• The CPS hasnt been useful in TMBs for a number
  of releases of reco.
• All p13 versions of reco had issues which mean
  that the TMBs didnt have the right cps
  clusters for about 80 of Z-gtee events.
• P14.03.0N (where N isnt 0) had issues such that
  the resolution is very bad.
• P14.00, P14.01, P14.02, P14.03.00, and P14.04
  appear to work fine for the CPS.
• Harry Melanson has added CPS plots to recocert so
  this type of problem will be caught before a
  release is frozen.

8
Hardware Changes

• Change the dynamic range for all channels. (Ramp
  trim by x3)
• Make them more uniform in saturation value, but
  less uniform in threshold.
• May apply offline threshold to make them more
  uniform, and to reduce the number of noise
  hitsfakes

9
Software Changes

• Currently CPS_reco uses different parameters for
  data and MC.
• The data will be stable, so the MC will be
  changed to reflect those operating parameters.
• Need to consider rewriting parts of the CPS code
  to reduce the size of (the cps portion of) the
  DST.
• Would be nice to have the individual strip
  information at the TMB.
• Improvements in the CPS discriminate and
  inclusion in EM likelihood.

10
Summary

• For almost all its purposes the CPS is ready for
  use.
• The one exception is improving energy resolution
  for EM particles 40 GeV and above
• This exception will be fixed when we return to
  data taking after the shutdown.
• There is some good evidence that one can achieve
  serious improvements in electron identification
  with the CPS.
• Work underway on photon/p0 separation. (see next
  talk)