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, `D_1` and `D_2`, which are called dees as they look like the letter `D`
The whole assembly is evacuated to minimise collisions between the ions and the air molecules. A high frequency alternating voltage is applied to the dees., positive ions or positively charged particles (e.g., protons) are released at the centre P. They move
in a semi-circular path in one of the dees and arrive in the gap between the dees in a time interval T/2; where T, the period of revolution, is given
`T = 1/v_c = (2pim)/(qB)`
`v_c = (qB)/(2pim)`
This frequency is called the cyclotron frequency for obvious reasons and is denoted by `v_c`
The kinetic energy of the ions is given by,
`KE = 1/2 mv^2 = (q^2B^2R^2)/(2m)`
The operation of the cyclotron is based on the fact that the time for one revolution of an ion is independent of its speed or radius of its orbit. The cyclotron is used to bombard nuclei with energetic particles. 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.
The whole assembly is evacuated to minimise collisions between the ions and the air molecules. A high frequency alternating voltage is applied to the dees., positive ions or positively charged particles (e.g., protons) are released at the centre P. They move
in a semi-circular path in one of the dees and arrive in the gap between the dees in a time interval T/2; where T, the period of revolution, is given
`T = 1/v_c = (2pim)/(qB)`
`v_c = (qB)/(2pim)`
This frequency is called the cyclotron frequency for obvious reasons and is denoted by `v_c`
The kinetic energy of the ions is given by,
`KE = 1/2 mv^2 = (q^2B^2R^2)/(2m)`
The operation of the cyclotron is based on the fact that the time for one revolution of an ion is independent of its speed or radius of its orbit. The cyclotron is used to bombard nuclei with energetic particles. 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.