DETECTING RADIATION

 

Photographic Film

Around 1896 Henri Becquerel (pictured above) discovered radiation accidentally. Becquerel found that a photographic plate became 'fogged' when left next to a sample of Uranium (a now well-known radioactive element).

Two of Becquerel's colleagues Marie and Pierre Curie (pictured below with their daughter) later discovered two other radioactive elements they called Radium and Polonium. In fact it was Marie Curie that originally coined the phrase radioactivity. In 1903 both Becquerel and the Curies received the Nobel prize for Physics.

Photographic film is still used today to detect radiation. Scientists who work with radioactive materials (such as in the nuclear industry or radiography) wear badges that contain a piece of photographic film on their clothing. The film is checked from time to time to see if it is fogged. Any fogging of the film suggests an over exposure to radiation.

The Geiger Muller Tube

A simple diagram of a Geiger Muller tube.

A diagram showing how a Geiger Muller tube measures radioactivity

How a Geiger Muller tube works:

1.

Argon gas fills the inside of the tube.

2.

When alpha, beta or gamma radiation enters the tube the Argon atoms are ionised to give Argon ions.

3.

The positively charged Argon ions trigger a spark inside the tube and a clicking sound that you can hear (if your computer can receive sound) when you select this page.

4.

The counter detects the clicks thereby counting the number of radioactive particles emitted by the sample.

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