Strålningsmätning

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 11 apr 2020
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This document specifies a method for the measurement of 14C activity concentration in all types of water samples by liquid scintillation counting either directly on the test sample or following a chemical separation.

The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water, marine water, as well as cooling water, industrial water, domestic, and industrial wastewater.

The detection limit depends on the sample volume, the instrument used, the sample counting time, the background count rate, the detection efficiency and the chemical recovery. The method described in this document, using currently available liquid scintillation counters and suitable technical conditions has a detection limit as low as 1 Bq l−1, which is lower than the WHO criteria for safe consumption of drinking water (100 Bq·l-1). 14C activity concentrations can be measured up to 106 Bq l-1 without any sample dilution.

It is the user’s responsibility to ensure the validity of this test method for the water samples tested.

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 8 maj 2020
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This document specifies a method for the physical pre-treatment and conditioning of water samples and the determination of the activity concentration of various radionuclides emitting gamma rays with energies 40 keV < E < 2 MeV, by gamma-ray spectrometry according to the generic test method described in ISO 20042.

NOTE The determination of the activity concentration of radionuclides emitting gamma rays with energy below 40 keV and above 2 MeV is also possible within the scope of this document, provided both the calibration of the measuring system and the shielding are adapted to this purpose.

This document is only applicable to homogeneous samples. The lowest limit that can be measured as such, i.e. without dilution or concentration of the sample or anti Compton device is about 5.10-2 Bq/l for eg 137Cs. The upper limit of the activity corresponds to a dead time of 5%.

Depending on different factors, such as the energy of the gamma rays and the emission probability per nuclear disintegration, the size and geometry of the sample and the detector, the shielding, the counting time and other experimental parameters, the sample is concentrated by evaporation when activities below 5.10-2 Bq/l have to be measured. However, volatile radionuclides (e.g. radon and radioiodine) can be lost during the source preparation.

When the dead time is higher than 5%, the sample is either diluted or an aliquot of the sample is taken or the source to detector distance is increased or a correction for pile-up effects is applied.

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 8 maj 2020
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This document provides a selection of test methods and their associated principles for the measurement of the activity of 90Sr in equilibrium with 90Y, and 89Sr, pure beta-emitting radionuclides, in water samples. Different chemical separation methods are presented to produce strontium and yttrium sources, the activity of which are determined using a proportional counter (PC) or liquid scintillation counter (LSC).

The selection of a particular test method depends on the origin of the contamination, the characteristics of the water to be analyzed, the required accuracy of test results and the available resources of the laboratory.

These test methods are used for water monitoring following past or present, accidental or routine, liquid or gaseous discharges. It also covers the monitoring of contamination caused by global fallout.

When fallout occurs immediately following a nuclear accident, the contribution of 89Sr to the total amount of strontium activity is not negligible. This document provides test methods to determine the activity concentration of 90Sr in presence of 89Sr.

Kommittébeteckning: SIS/TK 405 (Kärnenergi)
Källa: ISO
Svarsdatum: den 19 maj 2020
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This part of ISO 12749 contains the terms, definitions, notes to entry and examples corresponding to the frequently used concepts which apply to diagnostic and therapeutic nuclear medicine.

It comprises the minimum essential information for each nuclear medicine concept represented by a single term. It provides the reader with the information required to approach this multidisciplinary speciality, such as medical, radiopharmacy and medical physics point of view. It is intended to facilitate communication and promote common understanding.