S-Cool Revision Summary

S-Cool Revision Summary

Each matter particle has an antimatter counterpart that has opposite charge and spin.

Antimatter can be produced in particle collisions in accelerators.

The energy in a linear accelerator (LINAC) is limited by its length.

The energy in a cyclotron is limited by relativistic mass increase.

The energy in a synchrotron is limited by the emission of synchrotron radiation.

Particle annihilation - When a particle meets its antiparticle they annihilate. Their mass is converted into energy in the form of gamma-ray photons.

Pair-production - A single gamma-ray photon passing close to a nucleus (its recoil conserves momentum) can spontaneously produce a particle-antiparticle pair.

The mass spectrometer was developed in the early part of the last century to determine the comparative masses of ionised atoms and, later, the relative abundances of isotopes.

In the late 1970s, the physicists at CERN (European Nuclear Research Centre) came up with a brilliant idea. If you could fire two particles in opposite directions and make them collide, you would effectively double the available energy at a stroke without increasing the maximum kinetic energy of the particles. This is the principle behind the large electron-positron collider (LEP) and in the proton-antiproton super proton synchrotron at CERN. The forces used to accelerate and bend the particles and antiparticles have the same effect on both but they act in opposite directions.

The existence of antimatter came as a surprise to physicists. This strange idea, however, reveals a much more fundamental idea about our universe: if particles of matter and antimatter can meet and annihilate producing energy, then matter itself can be changed into energy and vice versa!

Some scientists like to think of matter as being a 'frozen' form of energy. Under the correct conditions this energy can be recovered by 'unfreezing' the energy.

Einstein's famous equation E = mc2 summarises this idea. To find out how much energy is produced when a certain mass is changed to energy ('unfrozen!') simply multiply the mass by the speed of light squared (c2). As the speed of light is very large a tremendous amount of energy is released when a very small amount of mass is released.