A Victoreen, Model THYAC III (also denoted Model 430), radiation-monitor control unit. The fiberglass container for the electronics and batteries measures 21 cm in length by 11 cm in width and 18 cm in height. The unit could act both as a gamma counter with an internally-mounted Geiger-tube or as a beta or alpha counter with an externally-mounted, thin window, Geiger-tube or a scintillation detector. Switches on the control unit face allowed both range changes and a choice of Geiger-tube mode (gm) or scintillation-counter mode (scint). This unit was manufactured by the Victoreen Company and was used by the Atomic Energy Control Board to investigate the contamination in tailings in the Port Hope, ON, area.
