Ikhawunta ye-Geiger-Miller, noma ikhawunta ye-Geiger ngamafuphi, iyithuluzi lokubala elakhelwe ukuthola ukushuba kwemisebe ye-ionizing (izinhlayiya ze-alpha, izinhlayiya ze-beta, imisebe ye-gamma, nama-X ray).Lapho i-voltage esetshenziswa ophenyweni ifinyelela ebangeni elithile, ipheya ngalinye lama-ion elenziwe umsebe eshubhu lingakhuliswa ukuze kukhiqizwe ishayela likagesi elinosayizi ofanayo futhi lirekhodwe idivayisi ye-elekthronikhi exhunyiwe, ngaleyo ndlela kukala inani lemisebe isikhathi seyunithi.