Positron

The positron or anti-electron is an elementary particle, an antiparticle of the electron. It has the same amount of mass and spin as the electron; however, its charge is 1e, while that of the electron is -1e. It is not part of ordinary matter, but of antimatter, although they are produced in numerous radiochemical processes as part of nuclear transformations.

This particle was predicted by Paul Dirac in 1928, and later discovered in 1932 by the American physicist Carl David Anderson when photographing the traces of cosmic rays in a cloud chamber.

Currently, positrons are routinely used in nuclear medicine such as positron emission tomography.

Creation of positrons by laser pulse

In November 2008, Dr. Hui Chen of the Lawrence Livermore National Laboratory in the United States announced that she and her team had created positrons by shining a brief but intense laser pulse through a few millimeters of white gold foil. of thickness; this would have ionized the material and accelerated its electrons. The accelerated electrons emitted quanta of energy that, when decaying, gave rise to material particles and also resulting in positrons. Currently, the important laboratory production of 5 MeV positron-electron beams allows the investigation of multiple characteristics, such as the way in which how different elements react to 5 MeV positron interactions or impacts, how energy is transferred to particles, and the gamma-ray burst (GRB) shock effect.

Applications

Certain types of particle accelerator experiments involve the collision of positrons and electrons at relativistic speeds. The high-impact energy and mutual annihilation of these matter/antimatter opposites create a source of various subatomic particles. Physicists study the results of these collisions to test theoretical predictions and search for new types of particles.

The ALPHA experiment combines positrons with antiprotons to study the properties of antihydrogen.

Gamma rays, emitted indirectly by a positron-emitting radionuclide (tracer), are detected in positron emission tomography (PET) scanners used in hospitals. PET scanners create detailed three-dimensional images of metabolic activity within the human body.

An experimental tool called positron annihilation spectroscopy (PAS) is used in materials research to detect variations in density, defects, displacements, or even voids within a solid material.

The positron in science fiction

• No doubt the positron acquired fame in the different robot novels of Isaac Asimov. This particle was essential for the manufacture of positronic paths where it would then be programmed to the robot, making the times of mechanical neurons. Together the paths were coupled and positioned carefully in the head of it. The author admitted in life that he had taken this particle as a pillar of his robotic brains because it had recently been discovered and that would attract the interest of the readers of the time.

Likewise, the positron was used in different series as a source of energy for weapons and powers:

• In Digimon Adventure 02 Digimon Imperialdramon uses an attack known as "Positronic Light"
• In Neon Genesis Gospeln, by Hideaki Anno, the positronic rifle is used several times against invading angels, being the most remarkable Ramiel.
• In the new saga Star Trek, android Data is built with a positronic brain.
• In the movie The bicentennial man, the character played by the actor Robin Williams also uses a brain of the positronic type.
• In all accounts of science-fiction robots by Isaac Asimov, robots have a positronic brain. Later, the Asimov himself acknowledged that he had not thought of calling those brains computer or processor.
• In the movie GhostBusters, scientists catch ghosts using positron rays.
• In the Supergirl series, the DEO together with the president of the USA. U.S. wants to use a positron cannon to defeat the daxamite army and Mon-el's mother.
• In the film Tenet is used the physics of the positron as an example that legitimizes the possibility of travelling back in time, investing your own timeline.