On the use of NaI scintillation for high stability nuclear decay rate measurements

TL;DR

This paper demonstrates that a NaI(Tl) scintillation detector coupled with a CMOS camera can reliably measure nuclear decay rates with high stability and linearity over a wide range of activities, highlighting its potential for precision decay studies.

Contribution

The study introduces a novel gamma-ray detection method using NaI(Tl) scintillation and CMOS imaging, showing high linearity and stability without pulse counting.

Findings

Detector exhibits excellent linearity over three decades of activity levels.

No dead-time correction needed due to continuous imaging approach.

Observed decay rate drifts of a few percent over several days.

Abstract

We demonstrate the linearity and stability of a gamma-ray scintillation detector comprised of a NaI(Tl) crystal and a scientific-grade CMOS camera. After calibration, this detector exhibits excellent linearity more than three decades of activity levels. Because the detector is not counting pulses, no dead-time correction is required. When high activity sources are brought into close proximity to the NaI crystal, several minutes are required for the scintillation to achieve a steady state. On longer time scales, we measure drifts of a few percent over several days. These instabilities have important implications for precision determinations of nuclear decay rate stability.