I will be posting some results later today:
For the landau fits for gains
The Landau fits have also been used to subtract the MIP peak from the preshower and this can be compared to the unsubtracted dEdx plots per ring to examine the effect of the preshower
We did a quick study with the preshower data at hand to see how effective it was with some estimates made from the raw data
By examining the plots, all MIP peaks should be removed at 50 ADC units above pedestal.This estimate seems true for both Tower and Preshower
i.e (ADC-ADC_PEDESTAL)-50 = Electron rich region
Also a TPC momentum cut is made at 2 < p < 3 GeV
Our Summer Student, Jay, has made some plots with these condition to see the effect of the preshower on the electron resolution
TPC Energy Loss: dEdx plots
Note: logY axis--> The black line represents the Tower MIP subtracted, no preshower cuts
--> The red line represents the Tower and Preshower MIP subtracted
The black line represents the Tower pedestal subtracted
The red line represents the Tower pedestal subtracted and Preshower MIP subtracted
1) Adding the preshower reduced the hadron spectra region (dEdx < 3) without appearing to reduce the electron spectra (dEdx > 3)
2) A shoulder is seen in the electron region
3) The preshower reduces the spectra in the hadron region dEdx=2.5 by an order of magnitude