Design and performance of two CsI/NaI(Tl) calorimeters in an internal target detector setup

The design, construction and performance of two total-absorption calorimeters 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 electrons with energies up to 1.9 GeV and protons up to 600 MeV. Each calorimeter consists of three layers of CsI(Tl) blocks followed by two layers of NaI(Tl) blocks, a total of 16 radiation lengths of scintillating material. Scintillation light from the CsI(Tl) is collected by wavelength-shifter plates and sensed by silicon photodiodes connected to charge-sensitive preamplifiers. The NaI(Tl) is read out with photomultiplier tubes. An overview is given of the performance of these calorimeters together with the other components of the detector system under the background conditions of the internal target setup. The electron energy resolution obtained was ∼10% (FWHM). ((orig.))