How are antiprotons formed?

Antiprotons are known to be very fast, so they would be hard to get. Usually, they are produced when there are collisions that will take place, but not all collisions will be able to produce antiprotons. Professionals normally use some machines in order to separate the antiprotons that have formed with the use of magnetic fields.

The antiprotons are then guided to the antiproton decelerator so that they can be considerably slowed down — the slower that they become, the more that they can be seen. People had thought before that antiprotons did not exist until such time when studies and proof about them were released to the public.

For over twenty-five years, antiprotons have been detected in cosmic rays, first by balloon-borne experiments and more recently by satellite-based detectors. The standard picture for their presence in cosmic rays is that they are produced in collisions of cosmic ray protons with nuclei in the interstellar medium, via the reaction, where A represents a nucleus.

The secondary antiprotons then propagate through the galaxy, restricted by the galactic magnetic fields. Their energy spectrum is modified by collisions with other atoms in the interstellar medium, and antiprotons can also be lost by "leaking out" of the galaxy.

Unlike protons, the antiprotons are a lot harder to make. They do not exist freely in nature like normal matter. To make the antiprotons, experimental labs use a 120 giga electron volt beam of protons taken from the main injector. This beam is incident through the side of a drum shaped target made of nickel.

The drum is rotated quickly to prevent the beam from hitting the same spot over and over. This prevents the destruction of the target. This collision with the target produces many particles a very small portion of which are antiprotons.