A positron is a particle of elementary type (since there is no evidence that it is composed of other simpler particles) whose electrical charge is equal to that of the electron , though positive . By this characteristic, it is said that the positron is the antiparticle of this subatomic particle.
To clearly understand the notion of positron, other concepts must be addressed. Antiparticles, including positrons, are the counterpart of the particles: their masses they are identical, but the electric charges are reversed (positive / negative, negative / positive)
Antiparticles such as positrons (which are also called antielectrons ), on the other hand, form a type of matter called antimatter , as well as particles form common matter.
At the end of the decade of 1920 , the English physicist Paul Dirac supposed the existence of positrons. Finally in 1932 , the American Carl David Anderson He managed to confirm it from the study of cosmic rays. If the convention of nomenclature of particles, the name of the positron should be antielectron; the explanation that this was not the case in that it was the first antiparticle that was discovered and that its burden is positive.
The creation of positrons is produced by certain nuclear processes. In 2008 , scientists from an American laboratory managed to create positrons by applying a laser on a white gold surface.
At present, the medicine appeals to the emission of positrons for the realization of tomography that allow you to study brain activity. Positrons are also popular in the Science fiction : in the movie "The Ghostbusters" , positron rays are used to capture spectra while, in several books, Isaac Asimov He imagined that positrons could be used for the development of robotic brains.
To address the concept of antiparticle in more depth, let's take a theoretical physical object that we can call Of, of which we know all its properties, such as its load and its mass, so that we can anticipate its behavior through a series of equations. Your positron or antiparticle, which we will call antiOf, would have a behavior equal to that of Of, to the point of not being able to distinguish one object from another, if in the equations we changed the sign to the following three things:
* load : yes Of had a positive charge, so that it repel nearby positive charges, antiOf it would be negative, so it would be attracted to them and not yet meet all the requirements to be confused with the original particle;
* Parity : for this it is necessary to change the spatial coordinates of Of. For example, if it were found at point (4,4,4), its positron would be at (-4, -4, -4). Having achieved this, antiOf and the charges positive would happen to be in a "turned" world, but this would not modify the aforementioned behavior, so it would still be possible to distinguish between the particle and its antiparticle;
* time : This is the key point, since when changing sign the weather it is achieved that it travels in the opposite direction, that is, that it recedes, so that antiOf it approaches the positive charges we see it move away from them, as if it were a video played backwards, and so on.
In summary, through the conjugation of these three sign inversions, we obtain an antiparticle, a physical object that appears to behave in the same way as the original, although the reality is another, much more complex. In the case of the positron, its charge is positive, since the electron always has a negative charge; on the other hand, it is convenient to think more abstractly and simply assume that these are opposite charges, since this feature of the electron is arbitrary.