Abstract
Four Geiger-Muller (G-M) type survey meters were modified for continuous use in routine clinical monitoring and emergency preparedness situations. The meters were modified using readily available components from a local electronics store at minimum cost and labor. Simple wiring of each meter enabled them to operate on standard AC line voltage using a small DC transformer to supply adequate voltage to the unit and its nickel-cadmium (Ni-Cd) batteries. All units can be removed from the transformer and operated on the Ni-Cd batteries for routine monitoring. Most survey meters will operate continuously for over 48 hr before the Ni-Cd batteries need to be recharged. Pre- and post-modification meter calibrations indicate no change in instrument response. After 6 mo of testing the systems to determine reliability and constancy, all were found to be in good working order.
