Atom-Smashers

The search for the Antiproton was a much more difficult task. The energy required to produce one of these particles would be 1,836 times that of the positron because these two particles are 1,836 times heavier. It would be impossible to get alpha particles that were that energetic and the odds of there being a cosmic ray of sufficient energy were not good but physicists had an new tool at their disposal, the particle accelerator.

The idea of a particle accelerator is rather simple. You place charged particle (nuclei and protons) in an apparatus and accelerate them to very high velocities / energies using magnetic fields.

The practical application of the idea of a particle accelerator was first pioneered by John Cockcroft and Ernest Walton who built and used their particle accelerator to bombard Lithium-7 with protons of very high energy producing Beryllium-8. Beryllium-8 is extremely unstable and immediately breaks down into two Helium-4 atoms. For this first nuclear reaction using a particle accelerator they both received the Nobel Prize in 1931. Building on this success American Ernest Lawrence built a Cyclotron using a cycling magnetic field and a curved track to make the accelerated particles accelerate in a circle. This allowed for very high energies to be reached in a relatively small device and for this he received the Nobel Prize in 1939.

Using Cyclotrons physicists could accelerate particle to very high energies and then send them smashing into target materials. They could then analyze what types of particles were produced using magnetic fields to examine the charges and masses of the resulting sea of sub-atomic particle. The Physicists Segre and Chamberlain received the Nobel Prize for the discovery of the Antiproton in 1955 using this technique.

Next
Previous