Abstract: The invention concerns use of a Geiger-Muller tube, gamma-ray detector, specifically, the method and apparatus for reducing the "dead-time" of that detector. The tube's anode is alternately connectable to either a high or low voltage through one of a pair of transistorized switches. The higher voltage is sufficient to permit ionization of the gas in the tube while the lower voltage is too low to sustain ionization. The tube is normally connected to the higher voltage source. The initial ionization of the gas in the tube by gamma-rays produces an initially small voltage drop in the anode voltage which is amplified by an amplifier, the output of which actuates a monostable driven circuit to generate a pulse having a width of 3 to 10 microseconds, preferably 5 to 6 microseconds. The leading edge of that pulse momentarily turns on the transistor switch connecting the anode to the lower voltage so that the potential is lowered thereby draining away energy and inhibiting further ionization.