Ko Johannes Wilhelm "Hans" Geiger (; Tiamana: [ˈɡaɪɡɐ]; 30 Mahuru 1882 <unk> 24 Mahuru 1945) he kairangahau Tiamana. He tino rongonui ia hei kaihauturu o te waahanga kaitirotiro o te Geiger counter me te whakamatautau Geiger<unk>Marsden i kitea ai te karihi ngota. Ko ia te tuakana o te meteorologist me te climatologist Rudolf Geiger. Pātai: Ko wai i kitea te karihi ngota.
Ko Johannes Wilhelm "Hans" Geiger