The Basis of all Particle Accelerators
Particle accelerators consist of 4 main parts:
- Particle production
- Particle acceleration
- Particle guidance
- Particle containment
These parts are common to all systems – only the design and form of the system changes.
- Particle production depends on the particles used in the accelerator.
- At its simplest, this could be a hot wire producing electrons via thermionic emission.
- More complicated systems involve the use of radioactive sources or particle collisions from other particle accelerators to produce the particles.
- One feature common is the use of charged particles.
- The section of the accelerator which increases the energy of the charged particles.
- This usually uses potential difference to accelerate the charged particle.
- The energy increase is equal to eV (where e is the charge of the particle, and V is the accelerating potential difference) and results in an increase in the kinetic energy of the particles.
- Usually the particles are accelerated multiple times.
- but the speed canot be increased indefinitely, because when the speed increases mass of the particle also increases.
- Depending on the design of the accelerator, the charged particles may need to travel in a straight or curved path. If a curved path is required, the particles are deflected by a magnetic field – magnetic fields are chosen because they cause the particles to travel in a predictable circular path, which is easily modelled.
- Groups of similarly charged particles tend to separate from each other and hence need to be contained into a tight packed or beam.
- To do this, magnetic fields are often used as a containment field.
- This also helps to keep the particles away from the walls of the containment vessel and so stop them interacting with their surroundings.
- The containment vessel is evacuated in order to stop interactions with air.