SIST EN ISO 10703:2016

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wasserbeschaffenheit - Bestimmung der Aktivitätskonzentration von Radionukliden - Verfahren mittels hochauflösender Gammaspektrometrie (ISO 10703:2007)Qualité de l'eau - Détermination de l'activité volumique des radionucléides - Méthode par spectrométrie gamma à haute résolution (ISO 10703:2007)Water quality - Determination of the activity concentration of radionuclides - Method by high resolution gamma-ray spectrometry (ISO 10703:2007)17.240Merjenje sevanjaRadiation measurements13.060.60Preiskava fizikalnih lastnosti vodeExamination of physical properties of waterICS:Ta slovenski standard je istoveten z:EN ISO 10703:2015SIST EN ISO 10703:2016en,fr,de01-februar-2016SIST EN ISO 10703:2016SLOVENSKI
STANDARD



SIST EN ISO 10703:2016



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN ISO 10703
October
t r s w ICS
s uä r x rä x râ
s yä t v r English Version
Water quality æ Determination of the activity concentration of radionuclides æ Method by high resolution gammaæray Qualité de l 5eau æ Détermination de l 5activité volumique des radionucléides æ Méthode par spectrométrie
Wasserbeschaffenheit æ Bestimmung der Aktivitätskonzentration von Radionukliden æ Verfahren This European Standard was approved by CEN on
t y September
t r s wä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
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t r s w CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN ISO
s r y r uã t r s w ESIST EN ISO 10703:2016



EN ISO 10703:2015 (E) 2 Contents Page European foreword . 3
SIST EN ISO 10703:2016



EN ISO 10703:2015 (E) 3 European foreword The text of ISO 10703:2007 has been prepared by Technical Committee ISO/TC 147 “Water quality” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 10703:2015 by Technical Committee CEN/TC 230 “Water analysis” the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2016, and conflicting national standards shall be withdrawn at the latest by April 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 10703:2007 has been approved by CEN as EN ISO 10703:2015 without any modification. SIST EN ISO 10703:2016



SIST EN ISO 10703:2016



Reference numberISO 10703:2007(E)© ISO 2007
INTERNATIONAL STANDARD ISO10703Second edition2007-11-15Water quality — Determination of the activity concentration of radionuclides — Method by high resolution gamma-ray spectrometry Qualité de l'eau — Détermination de l'activité volumique des radionucléides — Méthode par spectrométrie gamma à haute résolution SIST EN ISO 10703:2016



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SIST EN ISO 10703:2016



ISO 10703:2007(E) © ISO 2007 – All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.2 4 Symbols and units.4 5 Principle.5 6 Reference sources.5 7 Reagents.5 8 Gamma spectrometry equipment.6 9 Sampling.8 10 Procedure.8 11 Expression of results.11 12 Test report.16 Annex A (informative)
Example of a carrier solution which can be added to the water sample when waste water from a nuclear power plant is investigated.17 Annex B (informative)
Calculation of the activity concentration from a gamma spectrum using a linear background subtraction (undisturbed peak).18 Bibliography.20
SIST EN ISO 10703:2016



ISO 10703:2007(E) iv © ISO 2007 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 10703 was prepared by Technical Committee ISO/TC 147, Water quality. This second edition cancels and replaces the first edition (ISO 10703:1997), which has been technically revised. SIST EN ISO 10703:2016



ISO 10703:2007(E) © ISO 2007 – All rights reserved vIntroduction This International Standard allows (after proper sampling, sample handling and, when necessary or desirable, sample preparation) the simultaneous determination of the activity concentration of several gamma-ray emitting radionuclides in water samples by gamma-ray spectrometry using high purity germanium [HPGe] detectors. Gamma-ray emitting radionuclides are widespread both as naturally occurring and as man-made radionuclides. Therefore, environmental samples usually contain a multitude of different gamma-ray emitters and high resolution gamma-ray spectrometry provides a useful analytical tool for environmental measurements.
SIST EN ISO 10703:2016



SIST EN ISO 10703:2016



INTERNATIONAL STANDARD ISO 10703:2007(E) © ISO 2007 – All rights reserved 1Water quality — Determination of the activity concentration of radionuclides — Method by high resolution gamma-ray spectrometry WARNING — Persons using this International Standard should be familiar with normal laboratory practice. This International Standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. IMPORTANT — It is absolutely essential that tests conducted in accordance with this International Standard be carried out by suitably trained staff. 1 Scope This International Standard specifies a method for the simultaneous determination of the activity concentration of various radionuclides emitting gamma rays with energies 40 keV < E < 2 MeV in water samples, by gamma-ray spectrometry using germanium detectors with high energy resolution in combination with a multichannel analyser. 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 International Standard, provided both the calibration of the measuring system and the shielding are adapted to this purpose. This International Standard includes the procedures for energy calibration, determination of the energy dependent sensitivity of the measuring system, the analysis of the spectra and the determination of the activity concentration of the various radionuclides in the sample studied. It is only applicable to homogeneous samples. Samples with activities typically between 1 Bq and 104 Bq can be measured as such, i.e. without dilution or concentration of the sample or special (electronic) devices. 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 should be concentrated by evaporation when activities below about 1 Bq have to be measured. Also, when the activity is considerably higher than 104 Bq, the sample should be either diluted or an aliquot of the sample should be taken or the source to detector distance should be increased, or a correction for pile-up effects should be applied. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 31-9, Quantities and units — Part 9: Atomic and nuclear physics ISO 3696, Water for analytical laboratory use — Specification and test methods ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and sampling techniques SIST EN ISO 10703:2016



ISO 10703:2007(E) 2 © ISO 2007 – All rights reserved ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water samples ISO 5667-14, Water quality — Sampling — Part 14: Guidance on quality assurance of environmental water sampling and handling ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML IEC 60973, Test procedures for germanium gamma-ray detectors IEC 61151, Nuclear instrumentation — Amplifiers and preamplifiers used with detectors of ionizing radiation — Test procedures IEC 61452, Nuclear instrumentation — Measurement of gamma-ray emission rates of radionuclides —Calibration and use of germanium spectrometers 3 Terms and definitions For the purposes of this document, the definitions, symbols and abbreviations given in ISO 31-9 and the following apply. 3.1 blank sample container of an identical composition to the one used for the water test sample filled with radon free demineralized water 3.2 dead time time interval which must elapse between the occurrence of two consecutive pulses or ionising events for them to be recognized by the detection system as separate pulses or events 3.3 dead time correction correction to be applied to the observed number of pulses in order to take into account the number of pulses lost during the dead time 3.4 decay constant λ 〈radionuclide in a particular energy state〉 quotient of dP by dt, where dP is the probability of a given nucleus undergoing a spontaneous nuclear transition from that energy state in the time interval dt d1dddPNtNtλ==− where N is the number of nuclei of concern existing at time t 3.5 efficiency under stated conditions of detection, the ratio of the number of detected gamma-photons to the number of gamma-photons of the same type emitted by the radiation source in the same time interval SIST EN ISO 10703:2016



ISO 10703:2007(E) © ISO 2007 – All rights reserved 33.6 energy resolution measure, at a given energy, of the smallest difference between the energy of two gamma rays which can be distinguished by the apparatus used for gamma-ray spectrometry 3.7 full energy peak peak of spectral response curve corresponding to the total absorption of the photon energy in the sensitive detector volume by the photoelectric effect or by consecutive photon interactions of pair production (only for photon energy > 1 022 keV), Compton scattering and photoelectric absorption 3.8 gamma cascade two or more different gamma-photons emitted successively within the resolution time, from one nucleus when it de-excites through one or more intermediate energy levels 3.9 gamma radiation electromagnetic radiation emitted in the process of nuclear transition or particle annihilation 3.10 gamma-ray spectrometry method of measuring gamma rays yielding the energy spectrum of the gamma radiation 3.11 pile-up processing by a radiation spectrometer of pulses resulting from the simultaneous absorption of particles, or photons, originating from different decaying nuclei, in the radiation detector. NOTE As a result, they are counted as one single particle or photon with an energy between the individual energies and the sum of these energies. 3.12 transition probability fraction of the nuclei which disintegrates in a specific way SIST EN ISO 10703:2016



ISO 10703:2007(E) 4 © ISO 2007 – All rights reserved 4 Symbols and units V Volume of the water sample for test, in litres A Activity of each radionuclide in calibration source, at the calibration time, in becquerels ,c,AAcc Activity concentration1) of each radionuclide, without and with corrections, expressed in becquerels per litre tg Sample spectrum counting time, in seconds t0 Background spectrum counting time, in seconds ts Calibration spectrum counting time, in seconds ,0,s,,,NENENEnnn Number of counts in the net area of the peak, at energy E, in the sample spectrum, in the background spectrum and in the calibration spectrum, respectively g,g0,gs,,,EEEnnn Number of counts in the gross area of the peak, at energy E, in the sample spectrum, in the background spectrum and in the calibration spectrum, respectively b,b0,bs,,,EEEnnn Number of counts in the background of the peak, at energy E, in the sample spectrum in the background spectrum and in the calibration spectrum, respectively Eε=βfficiency=of=the=detecto±=at=ene±gy=E at actual measurement geometry EP Probability of the emission of a gamma ray with energy E of each radionuclide, per decay λ=αecay=constant=of=each=±adion×clide,=in=±ecip±ocal=seconds=,c(),()AAucuc Standard uncertainty associated with the measurement result, without and with corrections, in becquerels per litre U Expanded uncertainty calculated by ()AUkuc=⋅ with k = 1, 2., in becquerels per litre ,c,AAcc∗∗ Decision threshold, without and with corrections, in becquerels per litre ##,c,AAcc Detection limit, without and with corrections, in becquerels per litre ,AAcc Lower and upper limits of the confidence interval, in becquerels per litre
1) “Volumic activity” is an alternative name for “Activity concentration". SIST EN ISO 10703:2016



ISO 10703:2007(E) © ISO 2007 – All rights reserved 55 Principle Gamma rays cause electron-hole pairs when interacting with matter. When a voltage is applied across a semiconductor detector, these electron hole-pairs are, after proper amplification, detected as current pulses. The pulse height is related to the energy absorbed from the gamma-photon or photons in the resolving time of the detector and electronics. By discriminating between the height of the pulses, a gamma-ray pulse height spectrum is obtained. After analysis of the spectrum, the various peaks are assigned to the radionuclides which emitted the corresponding gamma rays using the previously obtained energy detector calibration. The concentration of the radionuclides present in the sample is calculated using the previously obtained energy-dependent detector efficiency. 6 Reference sources All certified reference sources shall be traceable to a national or international standard. 6.1 Reference source(s) for energy calibration One or more reference sources emitting gamma rays with accurately known energies covering the entire energy range to be studied shall be used. It is recommended that photon-emitting sources be used which cover the energy region of interest. Choose the source so that at least nine full energy peaks uniformly divided throughout the energy range of interest are available; sources containing long-lived radionuclides (europium-152, americium-241, cobalt-60, caesium-137) are recommended for this purpose. For a periodical control on the energy calibration, a smaller number of energy peaks can be used. 6.2 Reference source(s) for efficiency calibration One or more reference sources, traceable to national or international standards, for which the uncertainty of the activity is stated shall be used. Multi-radionuclide sources may also be used. The energies of the emitted gamma rays shall be distributed over the entire energy range to be analysed, in such a way that the energy-dependent efficiency of the measuring apparatus can be determined in a sufficiently accurate way. For most purposes, the accuracy is sufficient if the difference in counting efficiency between two subsequent energies is smaller than 10 % of the counting efficiency at 120 keV, if the required radionuclides are available. For determining the activity of radionuclide-emitting gamma rays in the energy region 40 keV < E < 100 keV, the counting efficiency for these gamma rays should be determined by calibration with this particular radionuclide. NOTE For the energy range 100 keV < E < 2 000 keV, the following radionuclides can be used: manganese-54, cobalt-57, zinc-65, strontium-85, yttrium-88, cadmium-109, tin-113, caesium-137, cerium-139. Radionuclides with cascade transitions (e.g. cobalt-60 and caesium-134) are applied with caution. As mercury is volatile it cannot be incorporated in solid sources prepared by evaporation. 7 Reagents The following reagents shall be used when the sample is concentrated by evaporation with iodine retention. Use only reagents of recognized analytical grade and only water complying with grade 3 of ISO 3696 shall be used for all applications. 7.1 Nitric acid, concentrated, c(HNO3) = 15,8 mol/l, 69 % volume fraction or w/w, [ρ(HNO3) = 1,42 g/ml]. 7.2 Sulfuric acid, concentrated, c(H2SO4) = 17,9 mol/l, 95 % volume fraction or w/w, [ρ(H2SO4) = 1,84 g/ml]. SIST EN ISO 10703:2016



ISO 10703:2007(E) 6 © ISO 2007 – All rights reserved 7.3 Silver nitrate solution, c(AgNO3) = 3,2 g/l. Dissolve 3,2 g of silver nitrate in water acidified with 0,1 ml of nitric acid and dilute to a total volume of 1 l with water. 7.4 Potassium iodide solution, c(KI) = 1,3 g/l. Dissolve 1,3 g of potassium iodide in 1 l of water. 7.5 Sodium sulfite, Na2SO3. 7.6 Hydrogen peroxide solution, c(H2O2) = 0,3 g/l. 7.7 Sodium carbonate solution, Na2CO3, saturated at 20 °C. 8 Gamma spectrometry equipment
Basically the measuring apparatus consists of two parts, the detector and the device which handles, stores and analyses the signals from the detectors. The output of the detector is fed into a multichannel analyser and buffers (MCA and MCB) and all handling, display, storage and analysis of data is carried out by a microprocessor with software and peripheral hardware.
For electronic parts, digital components (DSP) are more and more commonly used. The apparatus shall consist of the parts described in 8.1 to 8.8. 8.1 High purity germanium detector The performance of the detector shall be tested as specified in IEC 60973. NOTE The detectors are commercially available mainly in three different shapes, each having its own advantage depending on the circumstances : planar, coaxial and well-type detectors. For example, coaxial detectors are generally used when large volumes of sample are available, whereas the well-type detectors are most efficient for small volumes. More detailed information on the detectors is given in Reference [1] in the Bibliography. 8.2 High voltage power supply WARNING – Take necessary safety precautions in accordance with the manufacturer's instructions. 8.3 Preamplifier The preamplifier determines to a high degree the quality of the entire measuring system, as both noise and energy resolution depend on the characteristics of the preamplifier. NOTE Usually the preamplifier is located very close to the detector. Cooling the input stage (FET) of the preamplifier decreases the noise level and improves the energy resolution. 8.4 Cryostat or electric cooler, to keep the detector close to the temperature of liquid nitrogen. Operation at a low temperature is required to reduce the leakage current and electronic noise level of the detector and preamplifier; it is recommended that an automatic switch off and an alarm signal be installed which are activated in the case of an increase of temperature (e.g. caused by malfunctioning of the cryostat or loss of liquid nitrogen).
The HPGe detector can be stored at room temperature; however, it shall be cooled when bias voltage is applied. SIST EN ISO 10703:2016



ISO 10703:2007(E) © ISO 2007 – All rights reserved 78.5 Shielding The detector shall be shielded from all sides (including the bottom) with lead or iron, to reduce background signals originating mainly from naturally occurring radionuclides. If measurements in the energy region 40 keV < E < 100 keV are to be made, the internal casing may consist of three successive layers of cadmium, copper and for instance polymethylmethacrylate to achieve a low and constant background by attenuating the X-ray produced in the shielding. Shielding is important to reduce background levels, especially if low activity levels are to be measured. The following measures can be taken: ⎯ use of low activity lead; no shielding close to the detector if at all possible; ⎯ ventilation, air filtration, other materials of the system and the construction of the system chosen carefully, in order to reduce activity concentrations to achieve low levels of background radiation. 8.6 Main amplifier The main amplifier shall have linear characteristics with respect to input and output signals, should have pulse-shaping capacities and shall be equipped with a pole-zero network and a DC-restorer. The conformity of the actual characteristics parameters with the manufacturer's specifications shall be tested as specified in IEC 61151. NOTE When high counting rates (> 5 000 s–1), are to be expected, a pulse pile-up rejection circuit can be useful.
8.7 Multichannel analyser (MCA) or multichannel buffer (MCB) The optimum number of channels depends on the energy resolution and the studied energy range. For good resolution in the energy range of 100 keV to 2 000 keV, 4 096-8 192 channels are required (see Reference [11]). 8.8 Computer, including peripherical devices and software The computer, in combination with the available hardware and software (see References [1] and [2]), should be able to: ⎯ read the data from the MCA or MCB; ⎯ reproduce these data on a video display, a plotter or a printer and store them; ⎯ determine the relation between channel number and corresponding energy over the entire energy range to be studied (energy calibration), by making use of the appropriate reference source; ⎯ determine the energy-dependent efficiency over the entire energy range to be studied (efficiency calibration), by making use of the appropriate reference source; ⎯ detect peaks, to determine the characteristics of the detected peaks such as the centroid, the full peak width at half maximum height, the number of net counts collected under the peak, and to determine the uncertainty of this number; ⎯ identify the radionuclides responsible for the observed full energy peaks by making use of radionuclide references, for instance see References [4] to [7]; ⎯ calculate the activity concentration of the respective radionuclides on the basis of the number of counts, the counting time, the counting efficiency and the data given in radionuclide references, for instance see References [4] to [7]; ⎯ calculate the standard uncertainty of the activity concentration of the identified radionuclides; SIST EN ISO 10703:2016



ISO 10703:2007(E) 8 © ISO 2007 – All rights reserved ⎯ calculate the detection limit and the decision threshold of radionuclides to be measured but not found in the sample.
It is recommended that the results of the computer analysis of the spectrum be visually checked regularly for obvious anomalies or errors. To check the performance of the apparatus, the use of a laboratory standard is recommended. Participation in intercomparison runs can also help to test the performance of the apparatus and analysis.
NOTE Whenever necessary, calculations and identification can be performed manually. 9 Sampling The sample shall be collected and preserved as specified in ISO 5667-1, ISO 5667-3 and ISO 5667-14. Particular attention shall be given to the following: ⎯ sample identification (place, time and procedure followed); ⎯ the time elapsed between the moment of sampling and the measurement of the sample; ⎯ homogeneity of the sample; if any particulate matter is present which can cause heterogeneity, this shall be removed by filtration, and the residue shall be measured separately if necessary; ⎯ for the sampling, polyethylene bottles should be used, cleaned with 1 mol/l hydrochloric acid, followed by leaching with dilute nitric acid solution and rinsing with distilled or deionized water; ⎯ depending on the time duration bet
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