A cyclotron is a mechanical device invented by the American nuclear scientist Ernest O. Lawrence in the year 1929-1930 to accelerate the charged particle. Initially, it was made in small size with a limit to speed up the particles or ions at low volts of energy.

The cyclotron, which was made earlier, had many limitations as it was incapable of accelerating small mass particles like electrons. These limitations of a cyclotron can be overcome by modulating the conventional cyclotron with modern particle accelerators, for example, synchro-cyclotron.

History of Cyclotron

A cyclotron is a mechanical device used to speed up the charged particle. These charged particles speed up at a huge rate. This device was invented by Ernest O. Lawrence in the year 1929-1930 to accelerate the charged particles for different purposes. He received the Nobel prize in physics for this invention in 1939.

The first construction was based on the principle of magnetic resonance accelerators. It was very small in size. While constructing the first cyclotron, Lawrence used the radio frequency oscillator, which can generate up to 10 watts. The other components of this cyclotron were electrodes, hydrogen ions, vacuum and a small size electromagnet. The base diameter of the chamber of this device was measured as 5 inches in length and can speed up the particles or ions from 5 to 45 megavolts of energy.

Facts of Cyclotron

• The earliest cyclotron made was the size of a radio set.
• A cyclotron is a type of particle accelerator which is used to speed up the ions and positively charged particles, rotating them in a circular path.
• Cyclotron is not suitable for speeding up the elements which have very low mass, such as electrons.

Limitations of Cyclotron

1. The mass of an electron is very small. Because of this reason, the cyclotron device is incapable of accelerating or speeding up the electron.
2. This device is also incapable of accelerating or speeding up the particles which have no charge (neutral particle).
3. Cyclotron devices speed up the particle at a high rate but less than the speed of the light wave.
4. In a cyclotron, it is very hard to keep the same uniform magnetic field in a huge area.

Why are cyclotrons not suitable for accelerating electrons?

The motion or the energy of the charged particle or ions in an electromagnetic field is given by the following expression.

E=q²B²R² ⁄ 2m

Here, q is the positive charge particle, R is the radius of the orbit at the time of exit, m is the mass of the particle, B is the magnetic field, and E is the kinetic energy. 

In this equation, the kinetic energy of the particle is inversely proportional to the mass of the particle. 

A cyclotron can only accelerate or speed up the particles which have high mass or heavy ions. Therefore, the cyclotron is not suitable for accelerating electrons as it is a light particle with a very low mass. Protons and neutrons are considered heavy particles, while electrons are lighter.

How to Overcome the Limitations of Cyclotron?

A cyclotron is designed to speed up the charged particles. This speeding up of the particle raises the mass of the particles. Let’s suppose the particle speed up by the cyclotron is equal to the speed of light. In this case, the mass of the charged particle will be,