A new method for detecting antineutrino radiation has been developed.

Researchers have developed a detection element consisting of two distinct light-emitting materials: plastic and a new scintillator based on calcium lithium silicate. These detectors are also referred to as phosphor sandwich detectors (from the English words phosphor and sandwich).

It is known that antineutrinos interact extremely weakly with matter. For reference: their range in steel without interaction is 100,000 times greater than the distance from the Earth to the Sun. However, when an antineutrino does interact with matter, it readily engages in reactions with protons—this interaction is known as "inverse beta decay." The products of inverse beta decay are a positron and a neutron.

In the experiment conducted by scientists, the light-emitting plastic served as a proton-rich target for antineutrinos, where the detection of positrons and the products of their annihilation—gamma quanta—would occur. The calcium lithium silicate was intended for detecting neutrons that interact with lithium atoms.

The phosphor sandwich was simultaneously irradiated with gamma quanta (simulating gamma radiation from positron annihilation) and neutrons. The results exceeded all expectations: due to the different luminescence timing of the phosphor components, it was observed that gamma quanta were primarily detected by the plastic, while neutrons were detected by the calcium lithium silicate, with an accuracy greater than researchers had anticipated.

The results obtained create opportunities for the development of compact antineutrino radiation detectors operating on a coincidence scheme—where, under a certain detector geometry, signals from gamma and neutron events are registered with a known time interval. Such detectors are crucial for remote monitoring of nuclear power plants, as the antineutrino method is the only unverifiable way to "look inside" a nuclear reactor.

Additionally, using the proposed phosphor sandwich, it is possible to simultaneously detect alpha and beta particles, which is applicable for radiation dosimetry.

The project involved scientists from the Institute of Nuclear Problems at Belarusian State University, as well as the companies "Radiation Instruments and New Components" and "ATOMTECH" (Minsk).

The research findings have been published in the journal Nuclear Instruments and Methods in Physics Research.