Dynamic Enhancement of Nitric Oxide Radioluminescence with Nitrogen Purge

Thomas Kerst,Juha Toivonen

doi:10.1038/s41598-019-50396-6

Abstract

Remote detection of alpha radiation is commonly realised by collecting the light, the radioluminescence, that is produced when alpha particles are stopped in air. Radioluminescence of nitric oxide (NO) is primarily emitted between 200 nm and 300 nm, which makes it possible to use it for remote detection under daylight conditions. Quenching by ambient oxygen and water vapour, however, makes it generally difficult to effectively create NO radioluminescence. We present the detection of intense NO radioluminescence in ambient air under standard indoor lighting conditions using a nitrogen purge. The nitrogen contained NO impurities that were intrinsic to the gas and had not explicitly been added. We study the mechanisms that govern the NO radioluminescence production and introduce a model to describe the dynamics of the process. The level of NO contained in the gas was found to determine how successful a purge can be. We conclude by discussing possible applications of the technique in nitrogen-flushed gloveboxes at nuclear facilities where NO concentration of 100 ppb–1 ppm would be sufficient for efficient optical alpha radiation detection in standard lighting conditions.

Highlights

Radioluminescence is a useful indicator for the presence of alpha radiation
The remote detection schemes demonstrated so far rely on the assumption that the presence of UV light is an indicator good enough to potentially reveal the presence of alpha radiation
With arrangement B we studied how useful of a nitrogen flush can be in producing nitric oxide (NO) radioluminescence in otherwise ambient air

Summary

Introduction

Radioluminescence is a useful indicator for the presence of alpha radiation. Unlike other forms of nuclear radiation, alpha radiation is very localised. Sunlight reaching the surface of the earth is such a light source[14] It is for this reason that remote detection of alpha radiation with sunlight present is a much more challenging task than without it[8,15]. Sand et al successfully built and demonstrated such a system in a field environment using a caesium-telluride PMT and a set of bandpass filters centred around 260 nm[8] Another successful demonstration of an optical system with a tailored response was by Ivanov et al who imaged N2 radioluminescence using a UVC-sensitive camera that at the same time was insensitive to sunlight[17]. By using solar blind optics, the detection system gains the ability to operate under daylight conditions but at the same time severely reduces its sensitivity

Methods

Results

Conclusion