26.07.2018 change 26.07.2018
Ludwika Tomala
Ludwika Tomala

#Askscientist: How to split an atom?

Photo: Fotolia Photo: Fotolia

To crack the nucleus of an atom, you must do what you do when cracking a nut - hit it with something. If you deliver enough energy, the forces binding the components of the nucleus will no longer be sufficient to keep it together, says particle physicist Prof. Grzegorz Wrochna.

During the Science Picnic, our visitors could pass their questions to scientists. Now we ask researchers some of these questions. With the question "How to split an atom?" we turned to elementary particle physicist Prof. Grzegorz Wrochna from the National Centre for Nuclear Research in Świerk.

Professor Wrochna says that this question needs to be clarified. After all, the atom consists of the atomic nucleus and electrons. "It`s easy to break down an atom by detaching the electron from the nucleus" - says Prof. Wrochna. He explains that to do this, you can, for example, apply X-rays to a material that, after all, consists of atoms. "This should be enough to tear off at least those external electrons from atoms" - says Prof. Wrochna. This is associated with the so-called photoelectric effect. Photons with sufficient energy - X-rays - can give electrons the energy needed to escape the nucleus.

"But this is probably not the answer you were looking for" - smiles the scientist. And he answers how to split the nucleus of an atom.

"Some atomic nuclei are not stable, they decay on their own. So sometimes you only have to wait to split the atom. Sometimes you have to wait a fraction of a second, and sometimes a few million years - if you have that much time" - the physicist jokes.

He explains that people have learned how to split atomic nuclei on demand. "If you want to break the nucleus, you have to hit it with something, for example with a proton accelerated to a high energy. It`s just like cracking a nut. If you apply enough energy, it can turn out that the forces binding individual elements are not sufficient to hold them together" - says the scientist.

There is also another way. "Only the atomic nuclei that have a specific configuration of neutrons and protons are stable. If a neutron is added to such a nucleus, it may stop being stable and decay after some time" - says the researcher. He adds that this is how nuclear reactors work. "We begin with an isotope of a nucleus with a slightly different number of neutrons and protons than a stable one. If that nucleus decays, it produces a neutron. If that neutron gets into a more stable nucleus, it may split it. And if that split produces more than one neutron and those neutrons have a chance to get to other nuclei and split them, we have a cascade - a chain reaction" - he says. And he adds that this is how a nuclear reactor works - a device for splitting atomic nuclei. In Poland, such a device is the MARIA reactor at the National Centre for Nuclear Research in Świerk.

The scientist adds that the nucleus of the lightest element - hydrogen - consists of a single proton. And the proton can only be split into quarks. "This is possible only in the largest accelerators - for example at the LHC near Geneva" - he concludes.

PAP - Science in Poland, Ludwika Tomala

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