Not all materials around us are stable. Some materials can undergo radioactive decay with the formation of more stable isotopes. Now scientists have observed for the first time a new mode of decay. In this decay, the lighter form of oxygen, oxygen-13 (with eight protons and five neutrons), decays into three helium nuclei (an atom with no surrounding electrons), a proton, and a positron (the antimatter version of the universe). electron).

Scientists observed this decay by watching a single nucleus break apart and measuring its decay products. The study was published in the journal Physical Review Letters.

Scientists have previously observed interesting ways of radioactive decay following a process called beta-plus decay. Here the proton transforms into a neutron and emits some of the energy produced, releasing a positron and an antineutrino. After this initial beta decay, the resulting core may have enough energy to boil off additional particles and make itself more stable.

This new mode of decay is the first observation of three helium nuclei (alpha particles) and a proton released after beta decay. The findings could tell scientists about decay processes and the properties of the nucleus before it decays.

In this experiment, the researchers used a particle accelerator known as a cyclotron at Texas A&M University’s Cyclotron Institute to create a beam of high-energy (about 10% of the speed of light) radioactive nuclei. They directed this beam of radioactive material, oxygen-13, onto a piece of equipment known as the Texas Active Target Time Projection Camera (TexAT TPC).

The material stays inside this detector, which is filled with carbon dioxide, and after about ten milliseconds it decays, emitting a positron and a neutrino (beta plus decay). Using the TexAT TPC, the researchers measured the particles boiling after beta decay, placing oxygen-13 in the detector one core at a time and waiting for it to decay.

They then analyzed the data using a computer program to identify traces the particles left behind in the gas. This allowed them to identify rare events (occurring only once in 1,200 decays) in which four particles are emitted after beta decay. Source