Kalmar "ionization tube" yawanci tana nufin nau'in na'urar lantarki mai cike da iskar gas wanda aka ƙera don gano ko auna radiation ionizing, kamar alpha, beta, ko gamma radiation. Lokacin da radiation ya ratsa ta cikin bututu, yana sanya iskar gas a ciki, yana haifar da wutar lantarki da za a iya aunawa wanda za a iya amfani da shi don nuna kasancewar ko ƙarfin radiation. cike da iskar gas, kamar helium ko argon, da kuma sanye take da daya ko fiye da na'urorin lantarki. Lokacin da radiation ya shiga cikin bututu, yana yin karo da kwayoyin iskar gas, yana haifar da ions masu caji da kuma mummunan cajin electrons. Ana iya jan hankalin waɗannan ƙwayoyin da aka caje zuwa electrodes, suna haifar da siginar lantarki wanda za'a iya aunawa da tantancewa. hoto na likita. Ana amfani da su sau da yawa tare da wasu nau'ikan na'urorin gano radiation, irin su Geiger counters ko scintillation detectors, don samar da ƙarin bayani game da radiation da ake ganowa.