Positrons are the antiparticles of electrons. The major difference from electrons is their positive charge. Positrons are formed during decay of nuclides that have an excess of protons in their nucleus compared to the number of neutrons. When decaying takes place, these radionuclides emit a positron and a neutrino.

Can we make positrons?

Cosmic ray collisions routinely produce positrons and antiprotons, but the probability of creating an antihelium atom is extremely low because of the huge amount of energy it would require.

Why does positron happen?

Positron emission happens when an up quark changes into a down quark, effectively converting a proton to a neutron. ) are stable in galactic cosmic rays, because the electrons are stripped away and the decay energy is too small for positron emission.