Oliphant spent much of his life designing and constructing particle accelerators, starting with his time at the Cavendish Laboratory, Cambridge University. Later he built a proton-synchrotron in Birmingham and tried, unsuccessfully, to establish one at the Australian National University.

Put simply, an accelerator takes a subatomic particle, speeds it up using electromagnetic fields, and fires the particle into a target. Around the target are detectors that record what happens.

The target can be a solid, liquid or a gas. In Oliphant's Cavendish Laboratory experiments, he used Lithium for his target (see Atomic Reactions).

Charged particles are such things as electrons (-), protons (+), and the nuclei of Deuterium (one neutron and one proton) and other light atoms. They all have an electric charge which can be either positive or negative.

The accelerator brings these particles to such extremely high speeds and energies by creating large electric fields which attract or repel the charged particles. This field moves down the accelerator, 'pushing' the particles along.

There are two general types of particle accelerators - linear and circular. Oliphant was involved with both kinds:

• Linear accelerators are basically built in a straight line. They are relatively easy and cheap to build, but the particles they produce are not as high-energy as those who go through a cyclotron.

• Circular accelerators (synchrotrons or cyclotrons) can provide very high-energy particles without having to be extremely long. A cyclotron is capable of generating particle energies between a few million and several tens of millions of electron volts. However, they are expensive and complicated to build.

Accelerators let physicists do two things:

• By increasing a particle's speed in an accelerator, its wavelength is decreased. It then acts more like a lump of matter than a light wave. Physicists can then use it to break up atoms, and see what's inside.

• The energy of fast particles is used to make the huge particles that physicists want to study.

Oliphant tried to establish a world-class accelerator at the Australian National University when the Research School of Physical Sciences was being established in the 1950's. He felt this would give the University international standing.

'Well, I think we were a little too late. The concept was all right ... This was a very major operation for us, and indeed it turned out to be to big really for Australia ... What I wanted was to see something in Australia in the top steps in the development of nuclear physics ... which, after all, is the physics of the universe and of the whole of matter.'^[1]