Particle accelerator

A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds.

Targets and Detectors

Targets

The output of a particle accelerator can generally be directed towards multiple lines of experiments, one at a given time, by means of a deviating electromagnet. This makes it possible to operate multiple experiments without needing to move things around or shut down the entire accelerator beam.

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Except for synchrotron radiation sources, the purpose of an accelerator is to generate high energy particles for interaction with matter.

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This is usually a fixed target, such as the phosphor coating on the back of the screen in the case of a television tube; a piece of uranium in an accelerator designed as a neutron source; or a tungsten target for an X-ray generator. In a linac, the target is simply fitted to the end of the accelerator. The particle track in a cyclotron is a spiral outwards from the centre of the circular machine, so the accelerated particles emerge from a fixed point as for a linear accelerator.

Related Topics:
Phosphor - Uranium

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For synchrotrons, the situation is more complex. Once the particles have been accelerated to the desired energy, a fast acting dipole magnet is used to switch the particles out of the circular synchrotron tube and towards the target.

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A variation commonly used for particle physics research is a collider, also called a storage ring collider. Two circular synchrotons are built in close proximity - usually on top of each other and using the same magnets (which are then of more complicated design to accommodate both beam tubes). Bunches of particles travel in opposite directions around the two accelerators and collide at intersections between them. This can increase the energy enormously; whereas in a fixed-target experiment the energy available to produce new particles is proportional to the square root of the beam energy, in a collider the available energy is linear.

Related Topics:
Particle physics - Collider

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