This International Standard specifies a method for the simultaneous determination of the activity concentration of various gamma rays with energies of 40 keV < E < 2 MeV of emitting radionuclides in water samples by gamma spectrometry using high energy resolution germanium detectors in conjunction with a multi-channel analyzer. NOTE The determination of the activity concentration of radionuclides emitting gamma rays with energies below 40 keV and above 2 MeV is also possible within the scope of this International Standard, provided that both the calibration of the measurement system and the shielding are adapted to this purpose. This International Standard covers the procedures for energy calibration, for determining the energy-dependent sensitivity of the measuring system, for analyzing the spectra and for determining the activity concentration of the various radionuclides in the sample examined. It is only applicable to homogeneous samples. Samples with activities typically between 1 Bq and 104 Bq can be measured in this way, ie without diluting or concentrating the sample and without special (electronic) devices. Depending on various factors such as the energy of the gamma rays and the probability of emission, the size and geometry of the sample and detector, the shielding, the measurement time and other experimental parameters, the sample should be concentrated by evaporation if activities below about 1 Bq need to be measured. Even if the activity is significantly higher than 104 Bq, the sample should either be diluted or an aliquot of the sample should be taken, or the distance between source and detector should be increased, or a correction for pile-up effects should be made.
EN ISO 10703:2015 Referenced Document
ASTM E181-10 Standard Test Methods for Detector Calibration and Analysis of Radionuclides
IEC 60973:1989 Test procedures for germanium gamma-ray detectors
IEC 61151:1992 Nuclear instrumentation; amplifiers and preamplifiers used with detectors of ionizing radiation; test procedures
IEC 61452:1995 Nuclear instrumentation - Measurement of gamma-ray emission rates of radionuclides - Calibration and use of germanium spectrometers
ISO 11929 Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of ionizing radiation - Fundamentals and application
ISO 31-9:1992 Quantities and units; part 9: atomic and nuclear physics
ISO 3696:1987 Water for analytical laboratory use; Specification and test methods
ISO 5667-14:1998 Water quality - Sampling - Part 14: Guidance on quality assurance of environmental water sampling and handling
ISO 5667-1:2006 Water quality - Sampling - Part 1: Guidance on the design of sampling programmes and sampling techniques
ISO 5667-3:2003 Water quality - Sampling - Part 3: Guidance on the preservation and handling of water samples
ISO/IEC Guide 98-3:2008 Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)
EN ISO 10703:2015 history
2021EN ISO 10703:2021 Water quality - Gamma-ray emitting radionuclides - Test method using high resolution gamma-ray spectrometry (ISO 10703:2021)
2015EN ISO 10703:2015 Water quality - Determination of the activity concentration of radionuclides - Method by high resolution gamma-ray spectrometry