Separation of γ/π^0 showers at high energies
We have designed and carried out simulation studies of a two layer Shower Maximum Detector diagonally off-set (SMD-dos) optimized for the separation of π^0 showers from γshowers in the 30 to 150 GeV energy range. For 90% γacceptance the SMD-dos yields π^0 rejection efficiency of 92+-4%, 87+-4% and 32+-2%, respectively, for 30, 50 and 150 GeV incident energies. We find that the SMD-dos is superior to a conventional geometry single-layer or mutiple-layer shower maximum detector (SMD), of equal granularity, by an average factor of ~1.5 over the 50 to 150 GeV energy range. We also find that the SMD-dos gives better π^0 rejection, for the same number of channels, than a SMD. At hadron - hadron colliders the signature of choice for the detection of the Higgs particle, in the mass range of 120 to 160 GeV, is via the decay H-->γγ. The addition of a SMD-dos to the planned detectors at the LHC would significantly reduce the background to the γ-signal coming from prolific π^0 production.