Stabilization in gamma-ray spectometry

Abstract

A calibration source (20) for a gamma-ray spectrometer (40) is provided. The calibration source comprises a radioactive material (30) comprising a radioactive isotope having a decay transition associated with emission of a radiation particle and a gamma-ray having a known energy, e.g. Na-22, and a solid-state detector (26A, 26B), e.g. a PIN photodiode, arranged to receive radiation particles emitted from the radioactive material. A gating circuit (32) is coupled to the solid-state detector and is operable to generate a gating signal in response to detection of a radiation particle in the solid-state detector. The gating signal may thus be used as an indicator that an energy deposit in a nearby gamma-ray spectrometer is associated with a decay transition in the radioactive isotope. Since these energy deposits are of a known energy, they can be used as reference points to calibrate the spectrometer response. Thus with calibration sources according to embodiments of the invention, spectral stabilization (i.e. accounting for a changing spectrometer response, as well as base calibration) may be performed in real time and in parallel with obtaining a spectrum of observed signal events (i.e. the spectrum of interest). Furthermore, this is achieved with little contamination of the spectrum events of interest.

Dependencies are inferred from the claim text.