Evidence for compensation and study of lateral shower development in Si/U hadron calorimeters

In an Si/U hadron calorimeter, using a combination of low-Z and high-Z materials for the absorber allows the reduction of the calorimeter response to the electromagnetic component of the incoming hadronic showers (the local hardening effect). As a result, a ratio varying from e/ pi >1 to e/ pi <1 is obtained as a function of the low-Z material thickness, demonstrating the possibility of achieving the compensation condition e/ pi =1. The findings presented support the choice, for the next generation of colliders, of a hadron calorimeter with silicon as the active medium and a combination of low-Z and high-Z materials as the absorbers. The experiments performed to obtain the findings presented are described in detail.<>