Sources of compensation in hadronic calorimeters

Monte Carlo simulations are presented using the CALOR code system to study the design of a large hybrid hadron calorimeter system employing a warm liquid active medium (tetramethylsilane, Si(CH3)4) and uranium plates in addition to a conventional Fe/plastic system. In the system described here, the uranium provides partial compensation by suppressing the electromagnetic cascade produced by incident electrons due to sampling inefficiencies. The results of the simulations also indicate that significant compensation is achieved (given small enough saturation) due to low energy recoil protons produced in collisions with low energy (1-20 MeV) cascade and fission neutrons in the active medium. Both compensation mechanisms are important to help balance the response of a calorimeter to incident electrons and hadrons, that is, to achieve a ratio of pulse heights (e/h≅1) which will lead to the best energy resolution. (orig.)