H Exp – Radiation and Matter 15 – Half-value thickness

Aim – To measure the half-value thickness of lead for gamma rays

Instructions

▪ Use the counter and timer to determine the background count rate.
▪ Click on the button to put the radioactive source in place.
▪ Click on one of the pieces of lead to place it between the source and the G.M tube.
▪ Record the measurements of count rate and thickness of the lead absorber.
▪ Remove the lead by clicking on it.
▪ Repeat the measurements for each of the lead absorbers.
▪ Draw a graph to determine the half-value thickness of lead.