The sensor comprises three 3"x3" NaI(Tl) detectors housed in 6" diameter lead shields. Each detector uses a NaI(Tl) crystal optically coupled to a photomultiplier tube and a Multi-Channel Analyser (MCA). The detectors make measurements over 1024 channels calibrated to correspond to 0-3 MeV energy range. The complete system is controlled through custom-designed Geotek MSCL software, which enables either multi-channel spectral measurements or simply total counts to be recorded. The software gives the user full control of sampling positions and intervals down the core and control of count times. All the electronics are supplied in a single integrated 19" rack unit that contains of all the necessary external electronics including the motor control unit, the microprocessor and rack mounted PC. |