The following video shows a demonstration of the decay of protactinium. The protactinium source is in a bottle just below the GM tube on the left hand side of the screen. Readings may be taken from the counter and corrected for background (around 6 counts every 10 seconds) and a decay curve plotted, from which the half-life may be calculated.
The readings are taken over ten second intervals with gaps of 2.5 seconds between each set of readings.
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