Design and Experimental Application of a Radon Diffusion Chamber for Determining Diffusion Coefficients in Membrane Materials

TL;DR

This paper presents a novel radon diffusion chamber for measuring diffusion coefficients in membrane materials, aiding the selection of effective radon barriers for low-background experiments.

Contribution

It introduces a new detector design and demonstrates its application in accurately measuring radon diffusion coefficients in various membrane materials.

Findings

Successfully measured diffusion coefficients for four membrane types.

Confirmed the detector design's effectiveness and rationality.

Provided data to guide radon shielding material selection.

Abstract

In recent years, the issue of radon emanation and diffusion has become a critical concern for rare decay experiments, such as JUNO and PandaX-4T. This paper introduces a detector design featuring a symmetric radon detector cavity for the quantitative assessment of membrane materials' radon blocking capabilities. The performance of this design is evaluated through the application of Fick's Law and the diffusion equation considering material solubility. Our detector has completed measurements of radon diffusion coefficients for four types of membrane materials currently used in experiments, which also confirms the rationality of this detector design. The findings are instrumental in guiding the selection and evaluation of optimal materials for radon shielding to reduce radon background, contributing to boost sensitivities of rare event research.