Show geiger counter invented in 1920 operation simple in 1920 a couple of research ers n developed an instrument for measuring radioactive radiation today the instrument is s embodied in a compact unit and Is known as the gelger counter familiar to every uranium hunter on the colorado plateau heart of df the instrument ig Is the gelger mueller tube dev developed by W gelger geiger and M M mueller the tube utilizes two of the properties of beta and gamma radiation t the he ability of gamma rays and beta particles to ionize a gas or to make a gas conductive to elec electricity ity inside the tube commonly found I 1 in n most detectors is a thin wire sealed e aled within the evacuated tube running parallel to the surface of the metal and electrically insulated from it the tube is connected in series with a battery 1 ery and earphones or a neon indicator d di cator r and the voltage is adjusted so that the tube will not conduct except when brought in into t 0 the field of radiation when the penetrating radioactive particles or rays enter the tube they ionize the gas and an electric current Is set mt up which causes the earphones to click or the neon lamp to flicker when the ow earphones click once or the neon tube fl ickers only once a ray or particle has passed thru the tube of course larger gelger counters are equipped with meters to measure the amount of radiation and other devices to provide users with average counts alpha rays are absorbed by most materials and the outer wall of the geiger gelger counter absorbs them so that they are not recorded |