Speaker
Summary
The energy resolution of a calorimeter is determined by fluctuations. In almost all
calorimeters the electromagnetic shower fraction fluctuation dominate the energy
resolution for hadrons and jets. The DREAM sampling calorimeter was built to
eliminate this source of fluctuations by allowing a determination, on an
event-by-event basis, of the electromagnetic shower fraction. This is achieved by
sampling the energy deposited in the calorimeter with two different active media,
scintillating and quartz fibers, which measure respectively the scintillating and the
Cherenkov light produced by the shower. The energy resolution of the DREAM
calorimeter is however not only limited by the sampling fluctuations but also by the
small Cherenkov light yield (8 photoelectrons per GeV) which contributes more than
35%/sqrt(E) to the measured hadronic energy resolution. In order to improve this
we investigated the possibility of using the dual-readout
approach in homogeneous calorimeters. This can be done provided that a way is found
to distinguish the Cherenkov and the scintillating light produced by the shower in
the homogeneous medium. In this presentation a report on the studies performed with
lead-tungstate and BGO crystals will be given.
