Design and construction of a multi-layer CsI(Tl) telescope for high-energy reaction studies

A prototype of a new CsI(Tl) telescope, which will be used in the reaction studies of light isotopes with energy of several hundred AMeV, has been constructed and tested at the Institute of Modern Physics, Chinese Academy of Sciences. The telescope has a multi-layer structure and the range information will be obtained to improve the particle identification performance. This prototype has seven layers of different thickness. A 5.0% (FWHM) energy resolution has been extracted for one of the layers in a beam test experiment. Obvious improvement for the identification of $^{14}$O and $^{15}$O isotopes was achieved by using the range information.