γ-Ray detection with CsI(Tl) scintillators of the FARCOS array

The measurement of the response function of the CsI(Tl) scintillators of the FARCOS array, to standard sources, cosmic rays and environmental background allows the assessment of their performance. Fast–Slow analysis discriminates between γ -rays and charged particles. The relatively good energy resolution allows the observation of well resolved escape peaks due to the interaction of the 4.44 MeV γ -ray generated by AmBe source. Furthermore, the small noise enables to discriminate from the background the annihilation 511 keV γ -rays of the 22 Na source. The energy loss of muons generated by cosmic rays has been also measured and the radioactive contaminants as 137 Cs, 40 K and 208 Tl have been identified. The quality of the detectors suggests the possibility to use the array also for the measurement of γ -ray decay in reactions induced by stable and radioactive beams, once a well-defined reaction channel has been identified. Moreover, a dedicated compact detection module as a portable, high efficiency radiation detector for the control of environmental contamination will be developed.