# Cyclotron

Physics

## definition

### Describe the limitations of cyclotron

Limitations of Cyclotron are as follows:
• Cyclotron cannot accelerate uncharged particles like neutrons.
• Cyclotron cannot accelerate electrons because of its small mass.
• It cannot accelerate positively charged particles with large mass due to relativistic effect.

## definition

### Cyclotron

The cyclotron is a machine to accelerate charged particles or ions to high energies.The cyclotron uses both electric and magnetic fields in combination to increase the energy of charged particles.As the fields are perpendicular to each other they are called crossed fields. Cyclotron uses the fact that the frequency of revolution of the charged particle in a magnetic field is independent of its energy. The particles move most of the time inside two semicircular disc-like metal containers, D1 and D2, which are called dees as they look like the letter D.Inside the metal boxes the particle is shielded and is not acted on by the electric field. The magnetic field, however, acts on the particle and makes it go round in a circular path inside a dee. Every time the particle moves from one dee to another it is acted upon by the electric field. The sign of the electric field is changed alternately in tune with the circular motion of the particle.This ensures that the particle is always accelerated by the electric field.Each time the acceleration increases the energy of the particle. As energy increases, the radius of the circular path increases. So the path is a spiral one.

## definition

### Cyclotron frequency

The cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicular to the direction of a uniform magnetic field  (constant magnitude and direction).

where is the particle mass, its charge and the magnetic field, is the time period and is the cyclotron frequency.

## definition

### Uses of cyclotron

The cyclotron is used to bombard nuclei with energetic particles, so accelerated by it, and study the resulting nuclear reactions. It is also used to implant ions into solids and modify their properties or even synthesise new materials. It is used in hospitals to produce radioactive substances which can be used in diagnosis and treatment.