A student sets up an experiment to measure the attenuation of gamma rays by a lead absorber as shown in the diagram.
With no lead absorber in place, the corrected count rate measured by the detector is 4800 counts per minute (cpm)4800\text{ counts per minute (cpm)}4800 counts per minute (cpm).
The half-value thickness (HVT) of lead for this specific energy of gamma radiation is 12 mm.
What is the expected count rate when a 24 mm thick lead absorber is placed between the source and the detector?
0 cpm0\text{ cpm}0 cpm
1200 cpm1200\text{ cpm}1200 cpm
2400 cpm2400\text{ cpm}2400 cpm
3600 cpm3600\text{ cpm}3600 cpm