I-counter ye-Geiger-Miller, okanye i-counter ye-Geiger ngokufutshane, sisixhobo sokubala esilungiselelwe ukufumanisa ubukhulu be-ionizing radiation (i-particle ye-alpha, i-beta particles, i-gamma ray, kunye ne-X-rays).Xa amandla ombane asetyenzisiweyo kwiprobe afikelela kuluhlu oluthile, iperi nganye yeeyoni ezifakwe kwi-ray ekwityhubhu inokwandiswa ukuze ivelise i-pulse yombane yobukhulu obufanayo kwaye irekhodwe ngesixhobo sombane esiqhagamshelweyo, ngaloo ndlela ilinganisa inani lemitha ixesha leyunithi.