Ever since I started diving deep into particle physics, I have been intrigued by the topic of antimatter. For antimatter to be studied, scientists have to produce it. Sure, antimatter is one of the coolest things about science, but how do you make it? It’s not like you can just go to the kitchen and whip up some antimatter on the spot. So how do you do it?
Particle-antiparticle pairs are produced simultaneously when enough energy is squeezed in a very small space, for instance, during high energy particle collisions at CERN. For this to occur, the energy given to the accelerated particles has to be at least equivalent to the mass of the new particles.
The more energy that is put into particle collisions, the more massive the particles and antiparticles that can be produced. When energy is transformed into mass, both antimatter and matter are produced. This is produced in many experiments in CERN.
In collisions at the Large Hadron Collider, the antiparticles produced cannot be trapped due to their very high energy. This leads to them being annihilated harmlessly in the detectors.
Antiproton Decelerator at CERN produces much slower antiprotons that can be trapped, where they are studied to help understand their nature better.
Inside a metal cylinder called a target, protons with an energy of 26 GeV (about 30 times their mass at rest) collide with nuclei, at CERN. For every million collisions, approximately four proton-antiproton pairs are produced.
Using magnetic fields, these antiprotons are separated from other particles. They are then guided towards the Antiproton Decelerator where they are slowed from 96% to 10% of the speed of light. For the particles to be stored and trapped, these particles are ejected and run through-beam pipes into experiments.
For humans to make one gram of antimatter with current technologies, it would take us about one billion years as CERN’s particle accelerators produce no more than 1 billionth of a gram per year, even if they were to use all of their accelerators.
Therefore, the total antimatter produced in the history of CERN is less than 10 nanograms, containing only enough energy to power a lightbulb of 60 W for four hours.
With current advancements, the efficiency of antimatter production is very low. The energy required to make antimatter is about one billion times more than is contained in its mass. Using the famous formula E = mc2, we find that 1 gram of antimatter contains:
0.001 kg x (300,000,000 m/s)2 = 90,000 GJ = 25 million kWh
To achieve one single gram of antimatter, we need 25 million billion kWh, and that is considering the low production efficiency! The cost for this would be more than a million billion euros, even at a discount for electric power.
Trapping of Antimatter
As mentioned previously, for antimatter to be studied, it needs to be separated from matter, or else it will be annihilated. Antimatter that is electrically charged, can be trapped inside what is called the Penning Trap, which requires an ultrahigh vacuum.
The charged antiparticles are forced to spiral around the magnetic field lines by the magnetic fields, while the electric fields restrict them along the magnetic axis, inside the trap.
At CERN, the Penning Trap has been used to trap electrically charged antiparticles (antiprotons). To produce antihydrogen atoms, the antiprotons were combined with positrons (antielectrons).
For storing antiparticles, the world record is held by the TRAP experiment at CERN. A single antiproton was kept in a Penning trap for 57 days! This helped the scientists to perform very precise measurements of its mass and charge before the trap was switched off and the antiproton annihilated.
Antimatter in Nature
In the form of cosmic rays, small amounts of antimatter constantly rain down on the Earth. At a rate ranging from less than one per square meter to more than 100 per square meter, these antimatter particles reach our atmosphere.
Scientists have also seen evidence of antimatter production above thunderstorms.
Only inside atoms are their true nature evident.
One of the many cool things about antimatter is that your body emits antimatter. Humans receive an annual 40-millirem dose from the natural radioactivity originating inside of them.
This is the same amount of radiation you would be exposed to from having four chest x-rays.
The radiation dose level can go up by one or two millirems for every eight hours you spend sleeping next to your similarly radioactive loved one.
Similarly, humans emit radiation because many of the foods you eat, the beverages you drink and even the air you breathe contain radionuclides such as Potassium-40 and Carbon-14.
The release of the particles occurs due to the decay of potassium K-40. They are incorporated into your molecules and eventually decay and produce radiation in your body.
When Potassium-40 decays, it releases a positron, the electron’s antimatter twin, so the human body also contains a small amount of antimatter. It is not long before these positrons bump into your electrons and annihilate into radiation in the form of gamma rays.
Other than the human body, bananas can also release antimatter! They produce one positron, the antimatter equivalent of an electron, about every 75 minutes. This occurs due to the bananas possessing a small amount of potassium-40.
Radiation in Nature
Radioactivity born inside your body is only a fraction of the radiation you naturally, and harmlessly, come in contact with, on an everyday basis. An average American receives a radiation dose of about 620 millirems every year.
From the food you eat to the house you live in, to the rocks and the soil, you walk on all expose you to low levels of radioactivity. Just eating a Brazil nut or going to the dentist can cause your radiation dose level to go up by a few millirems. Smoking cigarettes can increase it up to 16,000 millirems.
From outer space, cosmos rays and high energy radiation constantly plummet down to the Earth’s atmosphere. The collisions with other nuclei produce mesons, many of which decay into particles such as muons and neutrinos.
At a rate of about 10 per second, these particles pass through you and shower down on the surface of the Earth. They add about 27 millirems to the yearly dose of radiation and can sometimes disrupt our genetics, causing subtle mutations, and may be a contributing factor in evolution.
On top of blasting us with photons that dictate the way we see the world around us, our sun also invades the Earth’s atmosphere with particles called neutrinos. At a rate of nearly 100 trillion neutrinos, they zip through your body every second.
Other than the sun being the source for neutrinos, other sources also include nuclear reactions in other stars and on our planet. Outdating even your atoms, many neutrinos have been around since the first few seconds of the early universe.
However, since these particles are so weakly interacting, they pass right through you.
Scientists speculate that neutrinos may be their antiparticles.
From bananas to humans emitting antimatter, it, in itself, is an intriguing topic that fascinates most of us. We still have a long way to go until we can successfully use antimatter as a fuel for rocket ships, but the more we learn, the more we will know. We have come a long way since we first discovered the existence of antimatter among matter in 1932, but we still have a long path ahead. By the next century, perhaps we will be venturing the stars with the help of antimatter as fuels for our spaceships!
- Antimatter is produced during high energy particle collisions.
- Energy needs to be transformed into mass for antimatter and matter air to be produced.
- In the Large Hadron Collider, antimatter cannot be trapped, but in Antiproton Decelerators, it can.
- For antiprotons to be separated, magnetic fields are used.
- We haven’t produced a lot of antimatter; just enough to fuel a 60 W lightbulb for four hours.
- Antimatter is trapped inside what is called a Penning Trap.
- Antimatter can also be found in nature. For example, humans emit antimatter and so do bananas.
About the Author
Hey readers! If you have made it this far, then I would like to thank you for your time! Hopefully, you learned something new from this article! I am super passionate about learning about new things, specifically more about space, astronomy and anything to do with space. If you want to read more articles from me follow me on Medium and connect with me on LinkedIn! If you’d like to be tuned in for my monthly updates, subscribe to my newsletter!