FCAL Reconstruction 04/08/2012
There is a tunable parameter in the FCAL code with default:
MIN_CLUSTER_BLOCK_COUNT = 2;
At lower energies (<~500 MeV), this causes photon reconstruction efficiency to be lower because often only one block has energy deposited in it (above the 20 MeV threshold in mcsmear).
In single photon sample:
- red:
MIN_CLUSTER_BLOCK_COUNT = 1 - black:
MIN_CLUSTER_BLOCK_COUNT = 2
In b1pi events:
- Overall efficiency increases by ~6%: 78% -> 84%
- 15% in total photon count (after timing cut) (1.18->1.36)
1-block "clusters" will collect less energy than multi-block clusters of same photon energy-->will affect energy calibration, energy resolution
FCAL energy corrections
What's the deal with FCAL energy correction? current code by Mihajlo (DocDB 1093)
Assume form
, where E_c is the energy of clustered blocks and E_gamma is the energy of thrown photon.
Fit MC data for A,B,C,
.
In reconstruction, get E_corrected from E_clust by solving this equation iteratively.
