Radiation shielding

Why is it so important?

Shielding ourselves from the harmful effects of radiation is crucial to our continuing ability to exploit radioactivity for the good of humankind. Whether that's scientific research at accelerator/reactor facilities, or the treatment of tumours using protons, electrons, gamma rays, and other forms of radiation.

Aim of the resource

In this resource you will investigate the ability of various materials to effectively attenuate gamma rays.


Select a material from the list and click 'Start Measurement'. This will start a 5 second long measurement without any absorber between the source and detector. Hover over the bar once the measurement has finished to see how many counts were recorded by the detector.

Next, increase the thickness of the absorbing material using the '+' button and measure for another 5 seconds (this doesn't need to be done in order, for example you could measure 1.0 mm next, then 0.3 mm and so on). Complete these steps until you have a measurement for every thickness in the chart.

This resource is only currently supported on the most modern desktop browsers. Support for mobile browsers, including those in iOS and android will be made available in future releases. For the best results, use the latest version of the Chrome desktop browser in full-screen mode.

In case you missed it on the home page, here's the workbook to accompany these experiments.

Experiment 1 - Attenuation of 99mTc γ-rays with Pb

Experiment 1 set-up

Material thickness: 0.0 mm

Experiment 2 - Comparing Attenuators

Experiment 2 set-up

Material thickness: 0.0 mm