DESIGN AND PERFORMANCE OF 2 CSI NAI (TL) CALORIMETERS IN AN INTERNAL TARGET DETECTOR SETUP

The design, construction and performance of two total-absorption calor imeters for nuclear physics experiments is described. They are used in conjunction with an internal polarized deuterium target in the 2 GeV electron storage ring VEPP-3 in Novosibirsk to detect scattered electr ons with energies up to 1.9 GeV and protons up to 600 MeV. Each calori meter consists of three layers of CsI(Tl) blocks followed by two layer s of NaI(Tl) blocks, a total of 16 radiation lengths of scintillating material. Scintillation light from the CsI(Tl) is collected by wavelen gth-shifter plates and sensed by silicon photodiodes connected to char ge-sensitive preamplifiers. The NaI(Tl) is read out with photomultipli er tubes. An overview is given of the performance of these calorimeter s together with the other components of the detector system under the background conditions of the internal target setup. The electron energ y resolution obtained was almost-equal-to 10% (FWHM).