The spinthariscope is a brass tube
with
a zinc sulfide screen at one end, a small radium source on the end of a
needle just above the screen, and a magnifying lens at the other
end. The zinc
sulfide screen fluoresces when struck by alpha particles.
Look at the screen in a darkened
room with dark-adapted eyes and individual flashes can be seen.
The
needle can be raised and lowered using the thumbscrew.
NOTES
The spinthariscope shows what
happens inside a scintillation detector.