Nanoporosity imaging by positronium lifetime tomography

TL;DR

This paper introduces a novel positronium lifetime tomography technique that enables spatially resolved nanoporosity imaging, providing new insights into porous materials' structure and purity.

Contribution

It develops a new method for spatially resolved PALS, allowing for nanostructural tomography of extended objects using stationary positron sources.

Findings

First demonstration of porosity imaging with stationary positron sources.

Successful application to porous polymers, silica aerogel, and scintillator materials.

Provides detailed nanostructural characterization through positronium lifetime tomography.

Abstract

Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET tomograph is demonstrated