The world of ancient people was simple, understandable and consisted of four elements: water, earth, fire and air (in our modern understanding, these substances correspond to: liquid, solid, gaseous state and plasma). Greek philosophers went much further and found out that all matter is divided into the smallest particles - atoms (from the Greek "indivisible"). Thanks to subsequent generations, it was possible to learn that the surrounding space is much more complex than we imagined at the beginning. In this article, we will talk about what a positron is and its amazing properties.
Discovery of the positron
Scientists have found that the atom (this allegedly whole and indivisible particle) consists of electrons (negatively charged elements), protons and neutrons. Since nuclear physicists learned how to accelerate particles in special chambers, they have already found more than 200 different varieties of them that exist in space.
So what is a positron? In 1931, its appearance was theoretically predicted by the French physicist Paul Dirac. In the course of the relativistic problem being solved, he came to the conclusion that, in addition to the electron, there must exist in nature exactlythe same particle with identical mass, but only with a positive charge. It was later called the "positron".
It has a charge (+1), in contrast to (-1) for an electron and a similar mass of about 9, 103826 × 10-31 kg.
Regardless of the source, a positron will always tend to "combine" with any nearby electron.
The only differences between them are the charge and presence in the Universe, which is much lower than that of an electron. Being antimatter, a particle that comes into contact with ordinary matter explodes with pure energy.
Having found out what a positron is, the scientists went further in their experiments, allowing cosmic rays to pass through a cloud chamber, shielded with lead and installed in a magnetic field. There, electron-positron pairs could be observed, which were sometimes created, and after the appearance continued to move in opposite directions within the magnetic field.
Now I understand what a positron is. Like its negative counterpart, the antiparticle responds to electromagnetic fields and can be stored in a confined space using confinement techniques. She can also combine with anti-protons and anti-neutrons to create anti-atoms and anti-molecules.
Positrons exist at low densities throughout the space environment, so methods have even been proposed by some enthusiasts to harvest antimatter to harness its energy.
Annihilation
If a positron and an electron meet each other on the way, then this will happenphenomenon like annihilation. That is, both particles will destroy each other. However, when they collide, a certain amount of energy that they had and is called gamma radiation is ejected into space. A sign of annihilation is the appearance of two gamma quanta (photons) moving in different directions in order to maintain momentum.
There is also a reverse process - when a photon, under certain conditions, can again turn into an electron-positron pair.
In order for this pair to be born, one gamma-quantum must pass through some substance, for example, through a lead plate. In this case, the metal absorbs the momentum, but releases two oppositely charged particles in different directions.
Scope of application
We found out what happens when an electron interacts with a positron. The particle is currently most widely used in positron emission tomography, where a small amount of a radioisotope with a short half-life is injected into a patient, and after a short waiting period, the radioisotope concentrates in the tissues of interest and begins to break down, releasing positrons. These particles travel several millimeters before colliding with an electron and releasing gamma rays that can be captured by the scanner. This method is used for various diagnostic purposes, including studying the brain and detecting cancer cells throughout the body.
So, inIn this article, we learned about what a positron is, when and by whom it was discovered, its interaction with electrons, as well as the area in which knowledge about it is of practical use.
