Crookes Spinthariscope (ca. 1920s) |
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The spinthariscope was invented in 1903 by William Crookes. These two photos show an example of the first commercially-available version of the spinthariscope. This particular spinthariscope came from Robert Millikan's Laboratory at Cal Tech and dates from the 1920s or earlier. After dark-adapting the eyes, the viewer looks through the lens of the spintahriscope and observes a screen of zinc sulfide where tiny flashes of light appear, an image Crookes described as a "turbulent luminous sea." Each flash of light is produced by an alpha particle emitted from a tiny sample of radium on the tip of a pointer positioned just above the screen. The spinthariscope can be considered the first radiation counter, i.e., it is capable of recording individual events. |
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For a story about the spinthariscope of William Crookes, click here. |
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