P4-13: HALF-LIFE OF BARIUM 137

ID Code: P4-13
Purpose: Measure the half-life of Ba 137, approximately 156 seconds.
Description: The 660 keV gamma ray from a Cesium 137 source is actually from its beta decay daughter, Barium 137. The cesium decays into a metastable state of barium with a half-life of about 156 seconds. Using a chemical technique, easily done in class using the equipment in the photograph at the right above, the barium is separated out from the sample of radioactive powdered cesium. The 660 keV gamma rays from the decaying barium daughter are detected by a Geiger tube and a graph of counts versus time plotted for equal time intervals using a computer with the Universal Lab Interface and the radioactivity and graph plotting software. The decay curve, taken in about 5 minutes, is shown above
Availability: Available

Due to the age of the apparatus, this demonstration is no longer available.

However, some interesting websites to check out:
www.radprocalculator.com/
nuclear.physics.iastate.edu/npc.php