Cyclotron

A Cyclotron is a kind of atom smasher. It has been used to split the atoms of most elements. It is a machine which produces high speed beam of atomic particles. The beam contains protons, heavy hydrogen nuclei, our alpha particles. By firing high speed particles into the atom’s nucleus, scientist cause the nucleus to split in two. The high speed particles are called atomic bullets. Through nuclear reactions of this type, much has been learned about the nucleus and it’s structure.

How does Cyclotron work?

The main parts of a Cyclotron are an electromagnet, a vacuum chamber and two hollow, semicircular metal electrodes. The electrodes are called “dees“. Each electrode had a D shape. The dees are placed inside the vacuum chamber with their straight edges parallel and slightly separated. They look like a pillbox. The whole assembly sit between the poles of a large electromagnet. This a magnetic field runs through the dees.

Source

The dees of the Cyclotron are connected to a high voltage alternating current. The alternating current produces an electric field along the split between the dees. One dee is charged negatively. The other dee is charged positively. Since alternating current is used, the electric field and the charges on the dee keep changing. First, a dee is negative. Then it is positive. The change in charge on each dee occurs many time per second.

Atomic bullets are injected in the center of the chamber between the dees. These bullets are charged particles or “ions” travelling at very high speeds. One method of producing atomic bullets is through use of a heated wire and a gas. The hot wire inside the chamber knocks electrons from the atoms of the gas. Positively charged atomic nuclei are formed from the atoms. If the gas is hydrogen, protons are produced. Heavy hydrogen gas produces deuterons. A deuteron is a heavy hydrogen nucleus. Helium gas produces alpha particles. These particles become the bullets.

Regulating the performance parameters of accelerated particles – Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Fig-19-A-schematic-diagram-of-a-Cyclotron_fig4_280722233 [accessed 16 Jun, 2019]

What happens when atomic bullets are injected into the Cyclotron?

The particles used as bullets are acted on by two powerful forces. The two forces are the magnetic field and alternating electric current. They are deflected from a straight path into a curved path by the magnetic field. The positive particles are first drawn the negative dee. Then the magnetic field pulls the particles in a semi circular path back to the space between the dees. At the same time, the electrical charge on the dees is reversed. The positive particles are now attracted to the negative charge of the opposite dees. Again the magnetic fields pulls the particles back between the dees. And again the electric charge on the dees is reversed.

The rapid changing of the charge on the dees gives a constant acceleration to the particles. The particles soon reach a very high speed. They gain speed and kinetic energy as they whirl around through the dees. The particles travel in an ever-widening circle until they are near the our edge of the dees. Here they exit through a thin window as a beam of high particles. These alpha Ray’s have 4.5 times more energy than the natural alpha particles released from a radioactive element.

Featured Image: RFT-30 cyclotron built by the Korea Atomic Energy Research Institute in Jeollabuk-do
Source : KAERI

Author: Oyetunji

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