Physics:Crystal calorimeter

From HandWiki

A calorimeter made of homogeneous cells and towers, of high-Z inorganic scintillating materials, e.g. NaI(Tl), BGO, BaF2, CeF3, or CsI.

The materials may be impurity-activated scintillators such as NaI(Tl), or pure crystals like BGO; the latter are free from problems associated with non-uniform dopant distribution, but are usually also harder to grow. Materials are characterized by their radiation length X0 (ranging from 1.1 to 2.5 cm), and interaction length Hepb img157.gif (ranging from 22 to 41 cm), the light yield in photons per MeV and wavelength of emitted light, signal rise and decay times, afterglow (duration of light emission after excitation), etc. Overall, it is the physical size (cost) and the energy resolution that usually count most. Resolutions down to Hepb img158.gif have been discussed (Ferrere92, Lecoq93). For a comparison of crystals, Hepb img34.gif Gratta94 or Majewski92, also Barnett96.