Multiphase nanostructured organic scintillators for gamma-ray/neutron discrimination

The results of the research published on Advanced Materials
grafico del PSD con figura del materiale scintillatore

Scintillator materials emit pulses of light when exposed to ionizing radiation or high-energy charged particles. They are widely used are used for in security devices for against nuclear threats, radioactive materials, for medical diagnostics, and in high-energy physics experiments. For some of these applications, it is vital to be able to distinguish between neutrons, charged particles, and 𝜸 beams. This discrimination is usually possible by exploiting Pulse Shape Discrimination (PSD), a time-resolved detection technique, which is based on the dependence of the scintillation pulse duration on the nature of the incident radiation. The best PSD scintillators polymeric organic materials, which have several advantages over liquid or crystalline scintillator materials, including mechanical robustness and patternability, but are made with unversatile formulations and techniques that limit their sensitivity. 

In the article “Sensitized Triplet-Triplet Annihilation in Nanostructured Polymeric Scintillators Allows for Pulse Shape Discrimination” (doi: 10.1002/adma.202400443), published in the journal Advanced Materials (Wiley, Impact Factor 29.4, 2022 Journal Impact Factor, Journal Citation Reports (Clarivate Analytics, 2023)), Dr. Irene Villa, Prof. Francesco Meinardi and by Prof. Angelo Monguzzi propose an innovative approach for realizing PSD systems that are more sensitive and efficient in discrimination of radiation, developed with the Institute for Plasma Science and Technology of the CNR in Milan, Italy, the Adolphe Merkle research center in Freiburg, Switzerland.

This work demonstrates how a more sensitive and faster PSD sensor can be achieved by exploiting nanostructured polymer scintillators, consisting of a solid polymer matrix and liquid nanodomains in which a dye pair is dissolved. The liquid nature of the nanodomains makes it highly efficient to produce delayed scintillation through the interaction of the two dyes when the material is invested by high-energy particles.  In this way, 𝜶 particles and neutrons can be discriminated from 𝜸 beams with greater sensitivity and speed than that of several commercial scintillators, paving the way for the development of new detectors that are much more efficient for observing rare events or dark matter-related massive particles.