The Radon Monitoring System in Daya Bay Reactor Neutrino Experiment

TL;DR

The paper presents a highly sensitive, portable radon monitoring system developed for the Daya Bay Reactor Neutrino Experiment, capable of precise measurements in underground environments with remote operation capabilities.

Contribution

It introduces a novel, integrated radon monitoring system with high sensitivity, reliability, and remote control, tailored for underground neutrino experiment environments.

Findings

System achieves less than 10% statistical error in 1-hour measurements.

Capable of detecting radon levels as low as 50 Bq/m³.

Operational in multiple experimental halls since 2013.

Abstract

We developed a highly sensitive, reliable and portable automatic system (H$^{3}$) to monitor the radon concentration of the underground experimental halls of the Daya Bay Reactor Neutrino Experiment. H$^{3}$ is able to measure radon concentration with a statistical error less than 10\% in a 1-hour measurement of dehumidified air (R.H. 5\% at 25$^{\circ}$C) with radon concentration as low as 50 Bq/m$^{3}$. This is achieved by using a large radon progeny collection chamber, semiconductor $\alpha$-particle detector with high energy resolution, improved electronics and software. The integrated radon monitoring system is highly customizable to operate in different run modes at scheduled times and can be controlled remotely to sample radon in ambient air or in water from the water pools where the antineutrino detectors are being housed. The radon monitoring system has been running in the three experimental halls of the Daya Bay Reactor Neutrino Experiment since November 2013.