barrel
The Rugby Ball calorimeter is the most demanding detector of the LAGRANGE apparatus. It was designed and optimized for the measurement of intermediate energy photons.
The calorimeter is composed by 480 BGO crystals of 24 cm length (corresponding to 21 radiation lengths). Each crystal, housed in a carbon fibre basket, is viewed by a photomultiplier tube. This configuration allows for an excellent energy resolution to low and intermediate energy photons
Cut view of the Rugby Ball calorimeter and
Energy resolution (FWHM) of the BGO Rugby Ball calorimeter