Abstract

A hand-held gamma radiation probe is employed to locate radiation concentrations in animal tissue in conjunction with a control function providing an enhanced audio output particularly suited for cuing the user as to source position. The probe is positioned at a location on the animal body representing background radiation and a squelch low count rate is developed therefrom. The squelch low count rate is multiplied by a range factor to develop a squelch high count rate and frequencies are developed from a look-up frequency table from lowest to highest in correspondence with the developed high and low squelch count rates. Slew rate limiting of the count rates is provided by development of a squelch delta value representing the difference between the squelch high and low count rates divided by a time element. Selection of frequencies for audio output from the frequency table is limited by the value of the squelch delta value. A weighting of received radiation counts is carried out continuously to develop count rate values used by the system.