Post by Andrei Tchentchik on Aug 25, 2020 15:35:32 GMT 2
(.#496).- How can antimatter be produced ?
How can antimatter be produced ?
Richard Taillet
Teacher, Physical Researcher.
Published 07/01/2005 - Modified 10/28/2015.
Archives
Here we are going to focus on a very different use: to extract from this antimatter the maximum of information on the laws of physics and on our Universe! In this file we will dwell on the aspects related more directly to astrophysics.
• How can antimatter be produced ?
There are mainly two physical phenomena that lead to the production of antimatter:
A - Radioactivity ß +
Radioactivity designates the set of processes by which one atomic nucleus can transform into another, by emitting particles. There are several types of radioactivity, which we classify according to the type of particle emitted :
- alpha radioactivity: emission of two neutrons and two protons in the form of a helium nucleus.
- gamma radioactivity: emission of a high energy photon.
- ß- radioactivity: emission of an electron (and an antineutrino). This concerns nuclei rich in neutrons.
- ß + radioactivity: emission of a positron (and a neutrino). This concerns nuclei rich in protons.
Antimatter (positrons) is therefore created each time the nuclei sensitive to ß + radioactivity decay.
B - High energy collisions
Creation of an electron-positron pair by converting the energy of an incident photon.
When a particle undergoes a shock with another particle, part of the energy of the shock can convert into mass, this is one of the contents of the famous formula E = mc2.
This mass: these are particles and antiparticles, which can be emitted in different directions, so that they do not re-annihilate as soon as they are formed. For this to happen, the energy involved in this shock must be greater than the mass energy of the particles / antiparticles created. It therefore takes much less energy to create an electron-positron pair than a proton-antiproton pair, the first having a mass approximately 2000 times weaker than the second. In practice, it is only extremely violent phenomena that allow such creation of antimatter.
Creation of particles and antiparticles by collision of a proton on a proton at rest.
Note that each time an anti-particle is produced, a "normal" particle must also be produced, it is one of the fundamental laws of physics.
Note also that there are other more speculative processes, we will come back to this when the time comes to speculate.
F I N .
How can antimatter be produced ?
Richard Taillet
Teacher, Physical Researcher.
Published 07/01/2005 - Modified 10/28/2015.
Archives
Here we are going to focus on a very different use: to extract from this antimatter the maximum of information on the laws of physics and on our Universe! In this file we will dwell on the aspects related more directly to astrophysics.
• How can antimatter be produced ?
There are mainly two physical phenomena that lead to the production of antimatter:
A - Radioactivity ß +
Radioactivity designates the set of processes by which one atomic nucleus can transform into another, by emitting particles. There are several types of radioactivity, which we classify according to the type of particle emitted :
- alpha radioactivity: emission of two neutrons and two protons in the form of a helium nucleus.
- gamma radioactivity: emission of a high energy photon.
- ß- radioactivity: emission of an electron (and an antineutrino). This concerns nuclei rich in neutrons.
- ß + radioactivity: emission of a positron (and a neutrino). This concerns nuclei rich in protons.
Antimatter (positrons) is therefore created each time the nuclei sensitive to ß + radioactivity decay.
B - High energy collisions
Creation of an electron-positron pair by converting the energy of an incident photon.
When a particle undergoes a shock with another particle, part of the energy of the shock can convert into mass, this is one of the contents of the famous formula E = mc2.
This mass: these are particles and antiparticles, which can be emitted in different directions, so that they do not re-annihilate as soon as they are formed. For this to happen, the energy involved in this shock must be greater than the mass energy of the particles / antiparticles created. It therefore takes much less energy to create an electron-positron pair than a proton-antiproton pair, the first having a mass approximately 2000 times weaker than the second. In practice, it is only extremely violent phenomena that allow such creation of antimatter.
Creation of particles and antiparticles by collision of a proton on a proton at rest.
Note that each time an anti-particle is produced, a "normal" particle must also be produced, it is one of the fundamental laws of physics.
Note also that there are other more speculative processes, we will come back to this when the time comes to speculate.
F I N .
