Tried this out with a G-M counter, 50's Timex dial, and found it interesting. To active movie go to this link:
Radiation counter: Eberline Instruments Co., Santa Fe NM, model 10472-B161
Watch dial: Timex Southhampton, ca. 1955, radium painted
Setting: counter set to 10X, otherwise it would have been too many clicks. The actual counts you hear should be multiplied by ten. Each click is one disintegration event being recorded by the counter, and it eventually becomes a wall of sound as the clicks are too close together.
Alarm: this is arbritary and meaningless, and I was unable to turn it off. Alarm should be ignored.