Goal: reco isolated gammas from bht0,1,2 -triggered events 

Method: identify isolated EM shower and match BSMD cluster energy to tower energy, as exercised earlier on 4) demonstration of absolute calib algo on single particle M-C 

INPUT events: 7,574 events triggered by barrel HT0,1,2 (id 220500 or 220510 or 220520) from run 9047029.

Cluster finder algo (sliding window, 1+3+1 strips),  smd cluster threshold set at 5 keV,  use only barrel West.

Tower cluster is defined as 3x3 patch centered on the tower pointed by the SMD peak.

Assumed BSMD calibration:  

• ene(GeV)= (adc-ped)*1e-7, one constant for all barrel
• pedestals, status tables hand tuned, some modules are disabled, but crate 4 is on

Results for ~3,8K barrel triggered events (half of 7,6K was not used)

Fig 1, Any  Eta-cluster

TOP: a) Cluster (Geant) energy;

b) Cluster RMS, peak at 0.5 is from low energy pair of isolated strips with almost equal energy

c) # of cluster per event, 

BOTTOM: X-axis is eta location, 20 bins span eta [-1,+1]. d) cluster ene vs. eta, e) cluster RMS vs. eta,

f) cluster yield vs. eta & phi, white bands are masked modules.

Fig 2, Any  Phi-cluster

see Fig 1 for details

Fig 3, Isolated EM shower

TOP: a) cluster loss on subsequent cuts, b) # of accepted EM cluster vs. eta location,

c) ADC distribution of 3x3 tower cluster centered at SMD cluster. In principle you should see there 3 edges from bht0, bht1, and bht2 trigger.

BOTTOM: X-axis is eta location, 20 bins span eta [-1,+1].d) Eta-cluster , e) phi-cluster energy, f) hit tower ADC .

Fig 4a,b, Calibration plots

2  eta location of 0.1, 0.5  of reco EM cluster  are shown in 3 panels (2x2)

1D plots are ratios of the respective 2D plots.

The  mean values of 1D fits are  relative gains of BSMDP/BSMDP and  BSMD/BTOW .

Fig 4c, Same as above, eta=0.9