spin·thar·i·scope 
(spĭn-thărĭ-skōp′)
(spĭn-thărĭ-skōp′)n.
A device for observing individual scintillations produced by ionizing radiation, as one consisting of a tube with a magnifying lens at one end and a phosphorescent screen and speck of radioactive salt at the other.
[Greek spintharis, spark + -SCOPE.]
spin·thar′i·scopic (-skŏpĭk) adj.