BCAL Beam Test Plots, November 20, 2006

First go

• Gain Correction:
  1. Establish the means of each cell in the Monte Carlo and find the ratio wrt MC Cell 8 over whole tagger spectra
  2. Find the current ratio of each ADC in the beamtest data wrt to North 8
  3. Correct the ADC ratio to match the Monte Carlo Ratios
     • The ratio of MC Cell 8 to North 8 defines the MeV/Channel

North 7

North 8

North 9

North 12

${\frac {MC8}{North8}}=0.018{\frac {MeV}{Channel}}$

How does this look over the entire tagger spectrum?

The 0.151 MeV/Ch is for a tagger photon (digregard this). The others are for energy deposit in the scintillator.

What if we look at MC 8 vs North 8 with Tagger Energy cuts?

North8 300<Ephoton<400

MC8 300<Ephoton<400

$({\frac {MC8}{North8}})_{{300<Ephoton<400}}=0.0177{\frac {MeV}{Channel}}$

North8 500<Ephoton<600

MC8 500<Ephoton<600

$({\frac {MC8}{North8}})_{{500<Ephoton<600}}=0.0165{\frac {MeV}{Channel}}$

• Very Strange: Apparent Energy Dependence

How do we see what's going on?

1. Cuts: Trig==8 (MOR and BCal OR), Nphotons==1
   • Possibly there are e+e-, maybe. Need to check the veto but it doesn't seem to be in the Root Trees
   1. Cut out the lower hump from the ADC sum.

ADCsum South 200<Ephoton<300

ADCsum South 300<Ephoton<400

ADCsum South 500<Ephoton<600

• This seems to remove the "junk" from the left of the spectra, and will flatten out the MC8/North8 ratio. But what is the "junk?

• -This has a 2% or more effect on the mean for 300<Ephoton<400. Probably much larger effect for the lower energies.

• Compare North 8 over all spectra when cutting on adcsumN > Ch1000 ~ 140MeV to previous

${\frac {MC8}{North8}}=0.0167{\frac {MeV}{Channel}}$

Looks reasonably closer except for the excess at the front of the spectra. I expect this is the contribution of the electrons or whatnot, the "junk", that we need to cut out.