《粒子物理与核物理实验方法（二）》EmcRec0.ppt

EmcReconstructionClusteringElectro-ic shower in EMC?Cluster–A contiguous region of crystals above an energy threshold.?Clustering–Recursive searching of neighbors to find cluster.?Several clusters might be typical cluster for 1GeV photon?Seed: local maximum.?If one seed, cluster = shower.?If more seeds, the cluster is split into several showers. Each crystal in this cluster contributes a shared energy to each Splittingclusterseed findingsplittingShower Energy?E3x3: Energy sum of 9 crystals around the seed?E5x5: Energy sum of 25 crystals around the seed?EAll: Energy sum of all crystals in the shower?Energy spectrum–Peak: most probable energy– : full width at half maximum–Tail: caused by front material and crystal leakage?Energy resolution–Most important quantity–Definition: ?tailpeak/E peakE?E5x5spectrum for 1GeV photon/ %EE??Energy resolution VS photon energy?4/ ( / / )%EE E