Positron

These are also called anti-electrons as they possess an opposite charge to that of an electron, which is positively charged.

Positron, also known as antimatter, was discovered by an American physicist Carl Anderson. While working on research upon the cosmic rays in a cloud chamber, steam seemed to have condensed into fine droplets in the same path of the electrically charged particles. The presence of a magnetic field helps in the detection of the charges of the particles.

The positron has an electric charge of +1e, the same mass as an electron and a spin of ½.

Positrons are formed in a process where the nuclides with a higher number of protons in their nucleus undergo a decaying process from which the positron is born. During the process of decaying, it emits radionuclides which emits a positron along with a neutrino. The process of formation of the positron is known as Annihilation.

Positrons are also formed naturally. They are produced from the Beta+ decays of the radioactive isotopes that occur naturally. They are also formed from the interaction of gamma quanta with matter.

Function and uses of positrons

Positrons have a lower molecular mass. Due to their lower molecular weight, positrons can be produced in any environment with an adequately higher temperature than that of the room temperature.

The production of positrons can be both artificial and natural. The production of a positron from beta+ rays can be considered both artificial and natural. It is because of the fact that radioisotopes can be formed both naturally as well as artificially.

The best artificial production of positrons is made from the usage of a small ultra-intense laser to irradiate a thick gold foil, which in turn produces over 100 billion positrons.

Positrons, being stable in a vacuum, are highly reactive with electrons of even ordinary matter. They react with these electrons by the annihilation process and generate gamma radiation.

Positron emission takes place when a radioactive nucleus’s proton content changes into a neutron and results in the emission of positron and electron neutrino. Positrons, being beta particles, make a nucleus unstable if present in large amounts, i.e., if the number of protons is high in any nucleus, it becomes unstable. In such cases, the positron tends to decay and correct the imbalance that takes place.

In such scenarios, positron emission balances the imbalance by emitting the countably required neutrons to make the nucleus stable. Positron emission results in the emission of neutrons and decreases the number of protons. In the positron emission process, the atomic number of the particle decreases by one, and the mass number remains the same.

Examples of Positrons

Some examples of positrons are: Magnesium with a mass number 23 has 12 protons and 11 neutrons. The ratio of neutron to proton is 11:12, which has an unstable nucleus. So, it undergoes positron emission to form Sodium-23.

23                   22                   0

Mg ->   Na +      e   + ve

12             11           1         

Positrons play a vital role in medical technology. The Positron Emission Tomography (PET) is a technology that is used for the scanning of the brain and the nervous system. The PET scanner helps in the detection and mapping of the gulped substance by emitting positrons that are annihilated by surrounding electrons.

Accelerators used in hospitals use positron to produce the short-lived isotopes that are used as medical markers in positron emission tomography.

The positron emission tomography helps in the detection of cancer at an early stage. It also helps in the evaluation of cancer treatment.

Conclusion

The positron, which is known as the anti-electron, plays a very important role in balancing the presence of atoms in nature. Although they have the same mass and charge as electrons, the positron, when annihilated, gives rise to protons and neutrinos.

Positrons have many uses in hospital treatment. It helps in the detection of cancer. The  Positron Emission Tomography process uses the positron and helps in the detection and treatment of cancer at a very early stage.