Direct gamma-X spectrometry measurement of 129I in environmental samples using experimental self-absorption corrections
Abstract
Direct gamma-X spectrometry is a suitable technique for quantifying low-level 129I activity, down to a few becquerels per kilogram, in environmental samples. Direct gamma-X spectrometry is a non-destructive technique that is rapid, which can be used for measuring several radioisotopes (multielementary) and that is easy to implement. A description is given of an experimental method for determining the self-absorption correction in the low-energy range, below 25 keV, to quantify 129I in different environmental matrices. The method is based on the measurement of the mass energy-attenuation coefficient μm( E) of the sample and the standard used to calibrate the measuring system. The μm( E) data are introduced in a simplified formulation of the correction factor that is validated for several container-detector sets commonly used in low-level activity environmental measurement. The method has also been tested on 125I, 129I and 137Cs, using different energy transitions. For marine algae species with high iodine concentrations (>2×10 -3 as a fraction of mass), an original method of determining the 129I/ totalI ratio as against the μm( E) determination in the vicinity of the iodine K-absorption edge energy is described.
- Publication:
-
Nuclear Instruments and Methods in Physics Research A
- Pub Date:
- November 1999
- DOI:
- 10.1016/S0168-9002(99)00664-6
- Bibcode:
- 1999NIMPA.437..114B