Cockroft & Walton Experiment


Pair Production

Pair Annihilation

Particle Accelerators

Four Fundamental Forces

Familes of Particles

Quark Model

Fun Stuff!






Antimatter was discovered in 1932, by the American physicist Carl David Anderson.

Anderson was observing the tracks produced by cosmic rays in a cloud chamber (a chamber where moving charged particles produce visible tracks). Some of the tracks produced were similar to those that would be produced by electrons , but when a magnetic field was placed in the chamber, the particles deflected in the direction that a positively charged particle would.


What did this mean?

Anderson realised that a new particle was produced. It had the same mass and charge as the electron, but the charge was of the opposite sign.

It became known as the anti-particle of the electron and was named the positron.

We now know that each particle has an anti-particle. We usually denote an anti-particle with the same symbol as the particle with a bar over it.


Anti-Proton is

History of Antimatter:

English physicist Paul Dirac predicted mathematically the existence of positrons and other anti-particles, in the late 1920's

The existance of anti-protons and anti-neutrons was confirmed experimentally in 1955

Since then, the full range of anti-particles has been confirmed.