An Improved Shashlyk Calorimeter

Understand

Shashlyk electromagnetic calorimeter modules with an energy resolution of about 3%/sqrt{E (GeV)} for 50-1000 MeV photons has been developed, and a prototype tested.

• Details of these improved modules, including mechanical construction, selection of wave shifting fibers and photo-detectors, and development of a new scintillator with improved optical and mechanical properties are described.
• How the modules will perform in a large calorimeter was determined from prototype measurements.
• The experimentally determined characteristics of the calorimeter prototype show energy resolution of sigma_E/E=(1.96+-0.1)% \oplus (2.74+-0.05)%/sqrt{E}, time resolution of sigma_T = (72+-4)/sqrt{E} \oplus (14+-2)/E (ps), where photon energy E is given in GeV units and \oplus means a quadratic summation.