Animal feeding stuffs: Methods of sampling and analysis - Determination of the radionuclides Iodine-131, Caesium-134 and Caesium-137 in feed

This standard describes a method of Iodium-131, Caesium-134 and Caesium-137 massic activity (Bq/kg) determination in animal feed.
Today, the most commonly used method for identification and quantification of radioactivity from these radionuclides in feed samples is high-resolution gamma-ray spectrometry. It is based on analysis of full-energy peaks (FEP) of the emitted gamma rays. Therefore, care should be taken to use appropriate energy and efficiency calibrations for each detector and test portion used.
In this standard, general guidance on the preparation of feed samples is provided together with specific information on high resolution gamma-ray spectrometry of the three radionuclides Iodium-131, Caesium-134 and Caesium-137. More information on these and related topics can be found in specific standards referred to in this document. For example, generic advice on the equipment selection, detectors and quality assurance for gamma-ray spectrometry can be found in ISO 20042:2016. The current standard aims to be complementary to existing standards, as an aid to laboratory practitioners that are faced with a situation, which requires response to the current topic without having to go through and interpret standards with general descriptions of gamma-ray spectrometry in order to measure in a standardised way. This standard contains information specific to the three radionuclides that it covers. Examples are provided in Annex …(to be added).

Futtermittel: Probenahme- und Untersuchungsverfahren - Bestimmung der Radionuklide Jod-131, Cäsium-134 und Cäsium-137 in Futtermittel

Dieses Dokument beschreibt ein Verfahren zur Bestimmung der massenbezogenen Aktivität (Bq/kg) von 131I, 134Cs und 137Cs in Futtermitteln in Überwachungslaboren.
Es werden allgemeine Leitlinien zur Herstellung von Futtermittelproben und zur Messung der drei Radionuklide 131I, 134Cs und 137Cs mittels hochauflösender Gammaspektrometrie dargelegt. Zweck des vorliegenden Dokuments ist die Ergänzung von bereits vorhandenen Normen. Weiterführende Informationen zur Probenvorbereitung, Bestimmung des Feuchtegehalts und Gammaspektrometrie können den spezifischen Normen, auf die in diesem Dokument verwiesen wird, entnommen werden. Beispielsweise enthält ISO 20042 allgemeine Empfehlungen zur Auswahl von Geräten, zu Detektoren und zur Qualitätssicherung bei der Gammaspektrometrie.
Das Verfahren wurde in einem Ringversuch mit fünf Futtermittelproben für die Radionuklide 131I, 134Cs und 137Cs umfassend statistisch geprüft und evaluiert. Details zu den erfolgreich geprüften Arbeitsbereichen für jedes der untersuchten Radionuklide sind in Anhang C beschrieben.

Aliments des animaux : Méthodes d’échantillonnage et d’analyse - Détermination des radionucléides iode 131, césium 134 et césium 137 dans les matières premières et aliments composés pour animaux

Le présent document décrit une méthode de détermination de l’activité massique (Bq/kg) de l’131I, du 134Cs et du 137Cs dans les aliments composés pour animaux dans des laboratoires de surveillance.
Des recommandations générales relatives à la préparation d’échantillons d’aliments composés pour animaux et au mesurage des trois radionucléides 131I, 134Cs et 137Cs par spectrométrie gamma haute résolution sont fournies. Le présent document a pour vocation de compléter des normes existantes. De plus amples informations sur la préparation des échantillons, la détermination de la teneur en eau et la spectrométrie gamma sont proposées dans les normes spécifiques mentionnées dans le présent document. Par exemple, l’ISO 20042 fournit des conseils généraux relatifs à la sélection de l’équipement, aux détecteurs et à l’assurance qualité pour la spectrométrie gamma.
La méthode a fait l’objet d’une évaluation et de tests statistiques complets dans le cadre d’un essai interlaboratoires impliquant cinq échantillons d’aliments pour animaux pour les radionucléides 131I, 134Cs et 137Cs. Les détails concernant le domaine de mesure soumis à essai et validé pour chacun des radionucléides examinés sont présentés dans l’Annexe C.

Krma: metode vzorčenja in analize - Določevanje radionuklidnega joda-131, cezija-134 in cezija-137 v krmi

General Information

Status
Published
Public Enquiry End Date
19-Feb-2020
Publication Date
24-May-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
24-May-2021
Due Date
29-Jul-2021
Completion Date
25-May-2021

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SLOVENSKI STANDARD
SIST EN 17462:2021
01-julij-2021

Krma: metode vzorčenja in analize - Določevanje radionuklidnega joda-131, cezija-

134 in cezija-137 v krmi
Animal feeding stuffs: Methods of sampling and analysis - Determination of the
radionuclides Iodine-131, Caesium-134 and Caesium-137 in feed

Futtermittel: Probenahme- und Untersuchungsverfahren - Bestimmung der Radionuklide

Jod-131, Cäsium-134 und Cäsium-137 in Futtermittel

Aliments des animaux : Méthodes d’échantillonnage et d’analyse - Détermination des

radionucléides iode 131, césium 134 et césium 137 dans les matières premières et
aliments composés pour animaux
Ta slovenski standard je istoveten z: EN 17462:2021
ICS:
65.120 Krmila Animal feeding stuffs
SIST EN 17462:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 17462:2021
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SIST EN 17462:2021
EN 17462
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 65.120
English Version
Animal feeding stuffs: Methods of sampling and analysis -
Determination of the radionuclides Iodine-131, Caesium-
134 and Caesium-137 in feed

Aliments des animaux : Méthodes d'échantillonnage et Futtermittel: Probenahme- und

d'analyse - Détermination des radionucléides iode 131, Untersuchungsverfahren - Bestimmung der

césium 134 et césium 137 dans les matières premières Radionuklide Jod-131, Cäsium-134 und Cäsium-137 in

et aliments composés pour animaux Futtermittel
This European Standard was approved by CEN on 22 February 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17462:2021 E

worldwide for CEN national Members.
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SIST EN 17462:2021
EN 17462:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Symbols and abbreviations ......................................................................................................................... 8

4.1 Symbols ............................................................................................................................................................... 8

4.2 Abbreviations ................................................................................................................................................ 10

5 Principle .......................................................................................................................................................... 11

6 Safety precautions ....................................................................................................................................... 11

7 Apparatus ........................................................................................................................................................ 11

7.1 General ............................................................................................................................................................. 11

7.2 Equipment for test portion preparation .............................................................................................. 11

7.3 Containers to be used ................................................................................................................................. 12

8 Procedure........................................................................................................................................................ 12

8.1 Calibration ...................................................................................................................................................... 12

8.2 Test portion preparation .......................................................................................................................... 15

8.3 Spectrum recording ..................................................................................................................................... 16

8.4 Spectrum analysis ........................................................................................................................................ 16

8.5 Quality assurance ......................................................................................................................................... 17

9 Expression of results ................................................................................................................................... 18

9.1 Massic activity calculation ........................................................................................................................ 18

9.2 Characteristic limits .................................................................................................................................... 23

9.3 Precision .......................................................................................................................................................... 24

9.4 Test report ...................................................................................................................................................... 25

Annex A (informative) List of possible interfering gamma rays .............................................................. 26

Annex B (informative) Example of uncertainty budget in gamma-ray spectrometry using an

HPGe detector ................................................................................................................................................ 27

Annex C (informative) Results of the collaborative trial ............................................................................ 28

Bibliography ................................................................................................................................................................. 33

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SIST EN 17462:2021
EN 17462:2021 (E)
European foreword

This document (EN 17462:2021) has been prepared by Technical Committee CEN/TC 327 “Animal

feeding stuffs - Methods of sampling and analysis”, the secretariat of which is held by NEN.

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 October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document has been prepared under a standardization request given to CEN by the European

Commission and the European Free Trade Association.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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SIST EN 17462:2021
EN 17462:2021 (E)
Introduction
131 134 137

This document describes a method for I, Cs and Cs massic activity determination (Bq/kg) in

animal feeding stuffs. It was initiated by Directorate General for Health and Food Safety (DG SANTE) of

the European Commission following the accident in the Fukushima Daiichi nuclear power plant in

March 2011. The event highlighted the need for standardized measurements of the three most common

radioactive contaminants following such type of nuclear accident.

The most commonly used method for identification and quantification of these radionuclides in animal

feeding stuffs samples is high-resolution gamma-ray spectrometry. As this is a secondary measurement

method based on analysis of photopeaks of the emitted gamma rays, care should be taken to use

appropriate energy and efficiency calibrations for the detector and test portion used. This method of

massic activity determination is described in the present document.
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SIST EN 17462:2021
EN 17462:2021 (E)
1 Scope
131 134

This document describes a method for determination of the massic activity (Bq/kg) of I, Cs and

137
Cs in animal feeding stuffs in monitoring laboratories.

General guidance on the preparation of feed samples and the measurement of the three radionuclides

131 134 137

I, Cs and Cs by high resolution gamma-ray spectrometry is provided. The current document aims

to be complementary to existing standards. More information on sample preparation, moisture content

determination and gamma-ray spectrometry can be found in specific standards referred to in this

document. For example, generic advice on the equipment selection, detectors and quality assurance for

gamma-ray spectrometry can be found in ISO 20042 [4].

The method was fully statistically tested and evaluated in a collaborative trial comprising five animal

131 134 137

feeding stuff samples for the radionuclides I, Cs and Cs. Details on the successfully tested

working range for each of the examined radionuclides are described in Annex C.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the cited edition applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN ISO 662, Animal and vegetable fats and oils — Determination of moisture and volatile matter content

(ISO 662)

EN ISO 665, Oilseeds — Determination of moisture and volatile matter content (ISO 665)

EN ISO 712, Cereals and cereal products — Determination of moisture content — Reference method

(ISO 712)
EN ISO 6497, Animal feeding stuffs — Sampling (ISO 6497)

EN ISO 6540, Maize — Determination of moisture content (on milled grains and on whole grains)

(ISO 6540)

EN ISO 11929-1:2019, Determination of the characteristic limits (decision threshold, detection limit and

limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application

— Part 1: Elementary applications (ISO 11929-1)

ISO 771, Oilseed residues – Determination of moisture and volatile matter content

ISO 6496, Animal feeding stuffs — Determination of moisture and other volatile matter content

3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN ISO 6497 and the following

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
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SIST EN 17462:2021
EN 17462:2021 (E)
3.1
background
spectrum recorded by the gamma-ray detector when no sample is measured

Note 1 to entry: The spectral data, including full energy peaks, in such a spectrum is resulting from radioactive

decay occurring in the environment surrounding the detector (including the cosmic ray interactions) or in the

detector.
3.2
background continuum

events in the spectrum that form a smooth curve onto which the photopeaks are superimposed

Note 1 to entry: The continuum may arise from gamma-rays scattered inside the test sample or any surrounding

materials, from cosmic radiation or from radionuclides in the surrounding materials.

[SOURCE: ISO 20042:2019, 3.1 [4]]
3.3
blank sample

sample, liquid or solid, with very low to no activity for radiation of the same type and region of interest,

with a mass and a composition as close as possible to those of the test sample
[SOURCE: EN ISO 19581:2020, 3.1 [1]]
3.4
dead time

time during spectrum acquisition (real time) during which pulses are not recorded or processed

Note 1 to entry: Dead time is given by real time minus live time.
Note 2 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.5 [4]]
3.5
efficiency transfer
detection efficiency transfer

calculation that enables the user to establish the value of the detection efficiency for a given gamma-ray

peak in the spectrum of the test portion, when only the detection efficiency from an experimental

calibration with a reference source that may have a different composition, density and/or geometry

compared to the test portion is known
3.6
high resolution gamma-ray spectrometry
energy resolution obtained with a Ge(Li) or an HPGe detector
Note 1 to entry: This definition is specific to gamma-ray spectrometry.
3.7
laboratory sample

sample as prepared (from the lot) for sending to the laboratory and intended for inspection or testing

[SOURCE: EN ISO 6498:2012, 2.1.2 [2]]
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SIST EN 17462:2021
EN 17462:2021 (E)
3.8
live time
time during which pulses are processed during an acquisition (real) time
Note 1 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.12 [4]]
3.9
photopeak
full energy peak (FEP)

peak observed above the background continuum in a gamma-ray spectrum due to events that deposit

the full energy of the photon in the detector material, usually approximately Gaussian in shape

[SOURCE: ISO 20042:2019, 3.17 [4]]
3.10
real time
time taken to acquire a spectrum
Note 1 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.19 [4]]
3.11
sample holder

device that is specially designed to enable the placement of a given sample container in a well-defined

position on top of a specific detector
3.12
spectrometry system

complete assembly of the sensor and associated pulse-processing electronics that converts the gamma-

rays detected by the sensor into a pulse-height spectrum
[SOURCE: ISO 20042:2019, 3.22 [4]]
3.13
test portion

quantity of material drawn from the test sample (or from the laboratory sample if both are the same)

[SOURCE: EN ISO 6498:2012, 2.1.4 [2]]
3.14
test sample

subsample or sample prepared from the laboratory sample and from which test portions will be taken

[SOURCE: EN ISO 6498:2012, 2.1.3 [2]]
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SIST EN 17462:2021
EN 17462:2021 (E)
3.15
true coincidence summing
TCS
coincidence summing
cascade-summing

simultaneous detection of two or more gamma-rays in the spectrometry system, due to the emission of

a cascade of gamma-rays in the decay of a single nucleus in the test sample
[SOURCE: ISO 20042:2019, 3.24 [4]]
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the following symbols apply:
Symbol Name of quantity Unit

A activity of a reference radionuclide emitting photons of energy E in the calibration Bq

source, at the time of calibration

a annum (year), the tropical year which is approximately equal to 365,2422 d year

a massic activity at energy E of a radionuclide in the sample Bq/kg
134

a ; massic activity of Cs obtained using the gamma-ray of energy i, which is either Bq/kg

m,605
a 604,72 keV or 795,86 keV
m,796
134

massic activity of Cs based on the weighted mean calculation including the two Bq/kg

major gamma rays of this radionuclide
decision threshold Bq/kg
detection limit Bq/kg
true value of massic activity at energy E of a radionuclide in the sample Bq/kg
d day (1 day = 86 400 s) day
f factor to correct for gamma-ray attenuation within the test portion (self- -
att(E)
attenuation)
f factor to correct for decay between the reference time and the start of the -
measurement and during the measurement
131
NOTE 1 The latter is important for short-lived radionuclides like I.

f is the factor to correct for decay between the reference time and the start of the -

measurement
f is the factor to correct for decay during the measurement -
f composite correction factor for the gamma ray with energy E considering all -
necessary corrections as shown in Formula (6)
f factor to correct for geometry differences -
ftcs,E factor to correct for true coincidence summing effects -
NOTE 2 In this case, this is only applicable to 134Cs.
k coverage factor -
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SIST EN 17462:2021
EN 17462:2021 (E)
Symbol Name of quantity Unit
m quantity of the test portion kg
m corrected quantity of the test portion kg
m dry mass of the moisture content determination portion kg
m fresh mass of the test portion kg
m fresh mass of the moisture content determination portion kg
134
N number of gamma rays used for the calculation of massic activity for Cs -

n number of counts in the net area of the photopeak at energy E, in the background -

b,E
spectrum

n number of counts in the net area of the photopeak at energy E, in the test portion -

N,E
spectrum

P probability (per 100 decays) of the emission of a gamma ray with energy E by a -

radionuclide

NOTE 3 The probability can be expressed in percentage (%) or in absolute values.

r net count rate in the full energy peak at energy E s
N,E
T temperature °C
t background spectrum live time s
t test portion spectrum live time s
t time elapsed between the reference time and the start of the measurement s

NOTE 4 It will have a negative value when the measurement was started before the

reference time and a positive value when the measurement was started after the reference

time.
t test portion spectrum real time s
t calibration spectrum live time s
t1/2 half-life of a radionuclide s
U(a ) expanded uncertainty with coverage factor k calculated as U = k × u Bq/kg
u(a ) standard uncertainty of the massic activity Bq/kg

u(a ); standard uncertainty of the massic activity calculated for the two most intense Bq/kg

m,605
134
gamma rays (604,72 keV and 795,86 keV) of Cs
u(a )
m,796

u(n ) uncertainty of the net number of counts in the photopeak at energy E in the -

b,E
background spectrum

u(n ) uncertainty of the net number of counts in the photopeak at energy E in the test -

N,E
portion spectrum
u(r ) uncertainty of the net count rate -
N,E
u random uncertainty component -
rand

u (A) relative uncertainty of the activity of a reference radionuclide emitting photons of -

rel
energy E in the calibration source, at the time of calibration
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SIST EN 17462:2021
EN 17462:2021 (E)
Symbol Name of quantity Unit

u (f ) relative uncertainty of the factor to correct for decay between the reference time -

rel d
and the start of the measurement and during the measurement

u (f ) relative uncertainty of the composite correction factor for the gamma ray with -

rel E
energy E considering all necessary corrections as shown in Formula (6)

u (f ) relative uncertainty of the factor to correct for true coincidence summing effects -

rel tcs,E
u (m) relative uncertainty of the quantity of the test portion -
rel

u (P ) relative uncertainty of the probability (per 100 decays) of the emission of a gamma -

rel E
ray with energy E by a radionuclide
u (r ) relative uncertainty of the net count rate -
rel N,E

u (ε ) relative uncertainty of the detection efficiency at energy E for the specific -

rel E
measurement geometry and detector used
u systematic uncertainty component -
sys
utot total uncertainty calculated based on random and systematic components -
u(w) total standard uncertainty for coverage factor w -
u (w) relative value of total standard uncertainty for coverage factor w -
rel
  standard uncertainty of a as a function of its true value Bq/kg
( )
134

v ; v weighting factor for the calculation of massic activity of Cs using the two most -

605 796
intense gamma rays (604,72 keV and 795,86 keV)
w calibration factor -
ɛ detection efficiency at energy E for the specific measurement geometry and -
detector used
λ decay constant of a radionuclide s
4.2 Abbreviations
ALARA As low as reasonably achievable
FEP Full energy peak
FWHM Full width at half maximum
HPGe High purity germanium
IEC International Electrotechnical Commission
ISO International Organization for Standardization
TCS True coincidence summing
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SIST EN 17462:2021
EN 17462:2021 (E)
5 Principle

A homogenous test portion is placed in a measurement container. The container is positioned in front of

a high energy resolution (e.g. high purity germanium) detector in a well-defined position. The full-

energy peaks of the emitted gamma particles present in the test portion are analysed and massic

131 134 137

activities of I, Cs and Cs are quantified using the high resolution gamma-ray spectrometry

technique. Appropriate energy and efficiency calibration shall be applied for each detector and sample

used.
6 Safety precautions
The optimization (ALARA) principle shall be applied at all times.

Handling of the samples should be performed according to the local safety regulations.

Personal protective equipment like laboratory coat, gloves, protective eyewear and personal dosimeter

shall be worn during the test portion preparation. The gloves shall be changed when the preparation is

finished to avoid cross-contamination.

Laboratory samples shall be stored in a cool and dark place, at a temperature not exceeding room

temperature and not lower than 0 °C. Perishable materials shall be kept at a temperature of

1 °C < T < 5 °C.

Care shall be taken as losses of iodine can occur if the material is not properly preserved. If presence of

gaseous iodine is suspected hermetically sealed containers shall be used and empty space or air pockets

between the sample and the lid of the container shall be avoided. Bound iodine can also easily become

volatile in the presence of microorganisms (due to methylation), in acidic environments or at

temperatures higher than 80 °C.
7 Apparatus
7.1 General

All equipment used during sample preparation shall be cleaned after each use to avoid cross-

contamination.
7.2 Equipment for test portion preparation
7.2.1 General

This document only provides guidance specific to its scope concerning the equipment for test portion

preparation. More details and a comprehensive description can be found in EN ISO 6498 [2].

7.2.2 Balance

In the test portion preparation process a balance or scale sensitive to 0,1 % of the mass of the test

portion and with a capacity of at least the wet mass of the test portion shall be used to determine the

mass.
7.2.3 Thermostatically controlled heating chamber

If results normalized to the dry mass are required, an oven or another suitable thermostatically

controlled heating chamber shall be used. The equipment shall be calibrated and capable of maintaining

the temperature needed to analyse the moisture content of the material with an uncertainty that is at

most 2 °C.
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SIST EN 17462:2021
EN 17462:2021 (E)
7.2.4 Equipment for particle size reduction and homogenization

Mills and mixers should be used to reduce the particle size and homogenize the test portion, in

particular if the particle size of the initial material is > 6 mm.
7.2.5 Equipment for handling dry powdered materials

An ion blower or other type of equipment should be used to reduce static electricity.

After the transfer of the test portion to the measurement container, a tapper or vibrating table could be

used to compact the test portion and equalize its height.
7.2.6 Gamma-ray spectrometry equipment

A gamma-ray spectrometer with high energy resolution (e.g. an HPGe) detector coupled to a pulse

processing, a data acquisition system and a computer shall be used to collect the spectra.

It is recommended to use detectors whose energy resolution (FWHM) is better than 2,2 keV (for the

60 137

Co peak at 1 332 keV) and with a peak/Compton ratio between 50 and 80 for Cs. For more

information, see IEC 61452 [5].
7.3 Containers to be used
7.3.1 Moisture content determination container

A container able to withstand the drying temperature shall be used if moisture content determination is

required. It shall be suitable for containing a portion of a test sample required by the relevant ISO

standard used for moisture content determination without loss of sample material while permitting

water to evaporate.
7.3.2 Measurement container

Guidance information on a proper container for the test portion is given in ISO 20042 [4].

If the measurement container is to be reused, it shall first be emptied, cleaned and checked for

radiopurity as it could have become contaminated by the previously measured test portion.

8 Procedure
8.1 Calibration
8.1.1 General

The gamma-ray spectrometry detector shall be calibrated for energy and peak detection efficiency. The

calibration should follow the requirements of IEC 61452 [5].
8.1.2 Energy calibration

The sources used for the energy calibration may be point sources of a single nuclide emitting gamma

152

rays of different energies (e.g. Eu), multiple nuclide point sources or a series of sources containing

radionuclides emitting one or more gamma rays.

Emphasis should be placed on the energy interval 364 keV to 911 keV, as the main gamma rays of both

the radionuclides in the scope of this document and the potentially interfering radionuclides (listed in

Annex A) have energies in that interval.
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EN 17462:2021 (E)
8.1.3 Detection efficiency calibration

The counting detection efficiency for a gamma-ray energy is affected by five major factors:

— the intrinsic detector efficiency;
— the position of the source in relation to the detector;
— the physical dimensions of the measurement container;
— the density, matrix composition and the filling height of the test portion;

— the shield (indirectly by minimizing interfering radiation or environmental background).

The experimental calibration of the detection efficiency should be performed using a reference volume

source (i.e. not a point source) measured in the same container and position as the test portion. The

properties of the reference volume source should be as similar as possible to those of the test portion.

To account for differences in their properties proper techniques for efficiency transfer should be

applied (see below).

As spiking can result in an inhomogeneous activity distribution preparation of a reference volume

source in the laboratory is only possible if a reliable and validated spiking procedure is available. Blank

material can be spiked with a multi-nuclide solution, several individual solutions containing suitable

radionuclides or a solution of a single nuclide emitting many gamma rays. Attention should be paid to

cover the region of interest (364 keV to 911 keV).
The net count rate (r ) shall be calculated using Formula (1).
N,E
nn−×
Nb,,E E
r = (1)
N,E
where
r is the net count rate in the full energy peak at energy E, in s ;
N,E

n is the net number of counts in the peak, at energy E, in the test portion spectrum;

N,E

n is the number of net counts in the peak, at energy E, in the background spectrum;

b,E
is the test portion spectrum live time, in s;
is the background spectrum live time, in s.
The detection efficiency at the energy E (ε ) shoul
...

SLOVENSKI STANDARD
oSIST prEN 17462:2020
01-februar-2020

Krma: metode vzorčenja in analize - Določevanje radionuklidnega joda-131, cezija-

134 in cezija-137 v krmi
Animal feeding stuffs: Methods of sampling and analysis - Determination of the
radionuclides Iodine-131, Caesium-134 and Caesium-137 in feed

Futtermittel: Probenahme- und Untersuchungsverfahren - Bestimmung der Radionuklide

Jod-131, Cäsium-134 und Cäsium-137 in Futtermittel

Aliments des animaux : Méthodes d’échantillonnage et d’analyse - Détermination des

radionucléides iode 131, césium 134 et césium 137 dans les aliments composés pour

animaux
Ta slovenski standard je istoveten z: prEN 17462
ICS:
65.120 Krmila Animal feeding stuffs
oSIST prEN 17462:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17462:2020
DRAFT
EUROPEAN STANDARD
prEN 17462
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2019
ICS 65.120
English Version
Animal feeding stuffs: Methods of sampling and analysis -
Determination of the radionuclides Iodine-131, Caesium-
134 and Caesium-137 in feed

Aliments des animaux : Méthodes d'échantillonnage et Futtermittel: Probenahme- und

d'analyse - Détermination des radionucléides iode 131, Untersuchungsverfahren - Bestimmung der

césium 134 et césium 137 dans les aliments composés Radionuklide Jod-131, Cäsium-134 und Cäsium-137 in

pour animaux Futtermittel

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 327.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17462:2019 E

worldwide for CEN national Members.
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Contents Page

European foreword ......................................................................................................................................... 3

Introduction ....................................................................................................................................................... 4

1 Scope ...................................................................................................................................................... 5

2 Normative references ...................................................................................................................... 5

3 Terms and definitions ...................................................................................................................... 5

4 Symbols and abbreviations ............................................................................................................ 8

4.1 Symbols ................................................................................................................................................. 8

4.2 Abbreviations .................................................................................................................................... 11

5 Principle .............................................................................................................................................. 11

6 Safety precautions ........................................................................................................................... 11

7 Equipment .......................................................................................................................................... 12

7.1 General ................................................................................................................................................ 12

7.2 Equipment for test portion preparation ................................................................................. 12

7.3 Gamma-ray spectrometry equipment ...................................................................................... 12

7.4 Containers to be used ..................................................................................................................... 12

8 Procedure ........................................................................................................................................... 13

8.1 Calibration.......................................................................................................................................... 13

8.2 Test portion preparation .............................................................................................................. 16

8.3 Spectrum recording ........................................................................................................................ 16

8.4 Spectrum analysis ........................................................................................................................... 17

8.5 Quality assurance ............................................................................................................................ 17

9 Expression of results ...................................................................................................................... 18

9.1 Massic activity calculation ............................................................................................................ 18

9.2 Characteristic limits ....................................................................................................................... 24

9.3 Precision ............................................................................................................................................. 25

9.4 Test report ......................................................................................................................................... 26

Annex A (informative) List of possible interfering gamma rays from naturally occurring

radionuclides as well as from radionuclides that could be present in

environmental samples immediately after a nuclear accident or incident ............... 27

Annex B (informative) Example of uncertainty budget in gamma-ray spectrometry using

an HPGe detector ............................................................................................................................. 28

Annex C (informative) Results of the collaborative trial .................................................................. 29

Bibliography .................................................................................................................................................... 34

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European foreword

This document (prEN 17462:2019) has been prepared by Technical Committee CEN/TC 327

“Animal feeding stuffs: Methods of sampling and analysis”, the secretariat of which is held by NEN.

This document is currently submitted to the CEN Enquiry.

This document has been prepared under a standardization request given to CEN by the European

Commission and the European Free Trade Association.
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Introduction
131 134 137

This document describes a method for I, Cs and Cs massic activity determination (Bq/kg)

in animal feed. It was initiated by Directorate General for Health and Food Safety (DG SANTE) of

the European Commission following the accident in the Fukushima Daiichi nuclear power plant

in March 2011. The event highlighted the need for standardized measurements of the three most

common radioactive contaminants following such type of nuclear accident.

The most commonly used method for identification and quantification of these radionuclides in

animal feed samples is high-resolution gamma-ray spectrometry. As this is a secondary

measurement method based on analysis of photopeaks of the emitted gamma rays care should be

taken to use appropriate energy and efficiency calibrations for the detector and test portion used.

This method of massic activity determination is described in the present document.

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1 Scope
131 134

This document describes a method for determination of the massic activity (Bq/kg) of I, Cs

137
and Cs in animal feed in monitoring laboratories.

General guidance on the preparation of feed samples and the measurement of the three

131 134 137

radionuclides I, Cs and Cs by high resolution gamma-ray spectrometry is provided. The

current document aims to be complementary to existing standards. More information on sample

preparation, moisture content determination and gamma-ray spectrometry can be found in

specific standards referred to in this document. For example, generic advice on the equipment

selection, detectors and quality assurance for gamma-ray spectrometry can be found in

ISO 20042.

The method was fully statistically tested and evaluated in a collaborative trial comprising five

131 134 137

animal feeding stuff samples for the radionuclides I, Cs and Cs. Details on the successfully

tested working range for each of the examined radionuclides are described in Annex C.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the cited edition applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.
EN ISO 6497, Animal feeding stuffs - Sampling (ISO 6497)

ISO 11929-1, Determination of the characteristic limits (decision threshold, detection limit and

limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and

application - Part 1: Elementary applications

ISO 20042:2019, Measurement of radioactivity - Gamma-ray emitting radionuclides - Generic test

method using gamma-ray spectrometry
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN ISO 6497 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
background

spectrum recorded by the gamma-ray detector when no sample is measured; the spectral data,

including full energy peaks, in such a spectrum is resulting from radioactive decay occurring in

the environment surrounding the detector (including the cosmic ray interactions) or in the

detector
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3.2
background continuum

events in the spectrum that form a smooth curve onto which the photopeaks are superimposed

Note 1 to entry: The continuum may arise from gamma rays scattered inside the test sample or any

surrounding materials, from cosmic radiation or from radionuclides in the surrounding materials.

[SOURCE: ISO 20042:2019, 3.1]
3.3
blank sample

sample, liquid or solid, with very low to no activity for radiation of the same type and region of

interest, with a mass and a composition as close as possible to those of the test sample

[SOURCE: ISO 19581:2017, 3.1, see [1]]
3.4
coincidence summing
true coincidence summing (TCS)
cascade-summing

simultaneous detection of two or more gamma-rays in the spectrometry system, due to the

emission of a cascade of gamma-rays in the decay of a single nucleus in the test sample

[SOURCE: ISO 20042:2019, 3.24]
3.5
dead time

time during spectrum acquisition (real time) during which pulses are not recorded or processed

Note 1 to entry: Dead time is given by real time minus live time.
Note 2 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.5]
3.6
detection efficiency transfer
efficiency transfer

calculation that enables the user to establish the value of the detection efficiency for a given

gamma-ray peak in the spectrum of the test portion, when only the detection efficiency from an

experimental calibration with a reference source that may have a different composition, density

and/or geometry compared to the test portion is known
3.7
full energy peak (FEP)
see photopeak [3.12]
3.8
high energy resolution

relative term which in gamma-ray spectrometry refers to the energy resolution obtained with a

Ge(Li) or an HPGe detector
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3.9
laboratory sample

sample as prepared (from the lot) for sending to the laboratory and intended for inspection or

testing
[SOURCE: EN ISO 6498:2012, 2.1.2 [9]]
3.10
live time
time during which pulses are processed during an acquisition (real) time
Note 1 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.12]
3.11
photopeak
full energy peak (FEP)

peak observed above the background continuum in a gamma-ray spectrum due to events that

deposit the full energy of the photon in the detector material, usually approximately Gaussian in

shape
[SOURCE: ISO 20042:2019, 3.17]
3.12
real time
time taken to acquire a spectrum
Note 1 to entry: The time is given in seconds.
[SOURCE: ISO 20042:2019, 3.10]
3.13
sample holder

device that is specially designed to enable the placement of a given sample container in a well-

defined position on top of a specific detector
3.14
spectrometry system

complete assembly of the sensor and associated pulse-processing electronics that converts the

gamma rays detected by the sensor into a pulse-height spectrum
[SOURCE: ISO 20042:2019, 3.22
3.15
test portion

quantity of material drawn from the test sample (or from the laboratory sample if both are the

same)
[SOURCE: EN ISO 6498:2012, 2.1.4 [9]]
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3.16
test sample

subsample or sample prepared from the laboratory sample and from which test portions will be

taken
[SOURCE: EN ISO 6498:2012, 2.1.3 [9]]
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this document, the following symbols apply.
Symbol Name of quantity Unit
A activity of a reference radionuclide emitting photons of energy E in the Bq
calibration source, at the time of calibration
massic activity at energy E of a radionuclide in the sample Bq/kg
134
massic activity of Cs obtained using the gamma-ray of energy i, Bq/kg
aa;
m,605 m,796
which is either 604,72 keV or 795,86 keV
134
massic activity of Cs based on the weighted mean calculation Bq/kg
including the two major gamma rays of this radionuclide

a true value of massic activity at energy E of a radionuclide in the sample Bq/kg

decision threshold Bq/kg
detection limit Bq/kg
a annum (year), the tropical year which is approximately equal to year
365,2422 d
d day (1 day = 86 400 s) day
ɛ detection efficiency at energy E for the specific measurement geometry -
and detector used
factor to correct for gamma-ray attenuation within the test portion -
att E
( )
(self-attenuation)
factor to correct for decay between the reference time and the start of -
the measurement and during the measurement
131
NOTE 1 The latter is important for short-lived radionuclides like I.
is the factor to correct for decay between the reference time and the -
start of the measurement
is the factor to correct for decay during the measurement -
composite correction factor for the gamma ray with energy E -
considering all necessary corrections as shown in Formula (5)
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Symbol Name of quantity Unit
factor to correct for geometry differences -
factor to correct for true coincidence summing effects -
tcs,E
134
NOTE 2 In this case, this is only applicable to Cs.
decay constant of a radionuclide s
quantity of the test portion kg
corrected quantity of the test portion kg
fresh mass of the test portion kg
dry mass of the moisture content determination portion kg
fresh mass of the moisture content determination portion kg
number of gamma rays used for the calculation of massic activity for -
134
number of counts in the net area of the photopeak at energy E, in the -
NE,
test portion spectrum
number of counts in the net area of the photopeak at energy E, in the
bE,
background spectrum
P probability (per 100 decays) of the emission of a gamma ray with -
energy E by a radionuclide
NOTE 3 The probability can be expressed in percentage (%) or in
absolute values.
net count rate in the full energy peak at energy E s
NE,
background spectrum live time s
t test portion spectrum live time s
t time elapsed between the reference time and the start of the s
measurement
NOTE 4 It will have a negative value when the measurement was
started before the reference time and positive value when the
measurement was started after the reference time.
t test portion spectrum real time s
t calibration spectrum live time s
half-life of a radionuclide s
12/
relative uncertainty of the activity of a reference radionuclide emitting -
( )
rel
photons of energy E in the calibration source, at the time of calibration
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Symbol Name of quantity Unit
ua standard uncertainty of the massic activity Bq/kg
( )
expanded uncertainty with coverage factor k calculated as U =k× u
Bq/kg
U a
( )
standard uncertainty of the massic activity calculated for two most Bq/kg
ua ;
( )
m,605
134
intense gamma rays (604,72 keV and 795,86 keV) of Cs
( )
m,796
  standard uncertainty of a as a function of its true value Bq/kg
( ) m
relative uncertainty of the detection efficiency at energy E for the -
u ε
( )
rel E
specific measurement geometry and detector used
relative uncertainty of the composite correction factor for the gamma -
( )
rel E
ray with energy E considering all necessary corrections as shown in
Formula (5)
relative uncertainty of the factor to correct for decay between the -
( )
rel d
reference time and the start of the measurement and during the
measurement
relative uncertainty of the factor to correct for true coincidence -
( )
rel tcs,E
summing effects
relative uncertainty of the quantity of the test portion -
( )
rel
uncertainty of the net number of counts in the photopeak at energy E -
( )
NE,
in the test portion spectrum
uncertainty of the net number of counts in the photopeak at energy E -
un()
b,E
in the background spectrum
relative uncertainty of the probability (per 100 decays) of the emission -
( )
rel E
of a gamma ray with energy E by a radionuclide
uncertainty of the net count rate -
( )
NE,
relative uncertainty of the net count rate -
( )
rel N,E
random uncertainty component -
rand
systematic uncertainty component -
sys
total uncertainty calculated based on random and systematic -
tot
components
total standard uncertainty for coverage factor w
( )
relative value of total standard uncertainty for coverage factor w
( )
rel
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Symbol Name of quantity Unit
134
weighting factor for the calculation of massic activity of Cs using the -
v v
605 796
two most intense gamma rays (604,72 keV and 795,86 keV)
calibration factor -
coverage factor -
temperature °C
4.2 Abbreviations
ALARA As Low As Reasonably Achievable
CEN European Committee for Standardization (Comité Européen de Normalisation)
FEP Full Energy Peak
FWHM Full Width at Half Maximum
HPGe detector High Purity Germanium detector
IEC International Electrotechnical Commission
ISO International Organization for Standardization
TCS True Coincidence Summing
5 Principle

A homogenous test portion is placed in a measurement container. The container is positioned in

front of a high energy resolution (e.g. High Purity Germanium) detector in a well-defined position.

The full-energy peaks of the emitted gamma particles present in the test portion are analysed and

131 134 137

massic activities of I, Cs and Cs are quantified using the high resolution gamma-ray

spectrometry technique. Appropriate energy and efficiency calibration shall be applied for each

detector and sample used.
6 Safety precautions
The ALARA principle shall be applied at all times.

Handling of the samples shall be performed according to the local safety regulations.

Personal protective equipment like laboratory coat, gloves, protective eyewear and personal

dosimeter shall be worn during the test portion preparation. The gloves shall be changed when

the preparation is finished to avoid cross-contamination.

Laboratory samples shall be stored in a cool and dark place, at a temperature not exceeding room

temperature and not lower than 0 °C. Perishable materials shall be kept at a temperature of

1 °C < T < 5 °C.

Care shall be taken as losses of iodine may occur if the material is not properly preserved. If

presence of gaseous iodine is suspected hermetically sealed containers shall be used and empty

space or air pockets between the sample and the lid of the container shall be avoided. Bound

iodine may also easily become volatile in the presence of microorganisms (due to methylation), in

acidic environments or at temperatures higher than 80 °C.
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7 Equipment
7.1 General

All equipment used during sample preparation shall be cleaned after each use to avoid

cross-contamination.
7.2 Equipment for test portion preparation
7.2.1 General

This document only provides guidance specific to its scope concerning the equipment for test

portion preparation. More details and a comprehensive description can be found in EN ISO 6498

[9].
7.2.2 Balance

In the test portion preparation process a balance or scale sensitive to 0,1 % of the mass of the test

portion and with a capacity of at least the wet mass of the test portion shall be used to determine

the mass.
7.2.3 Thermostatically controlled heating chamber

If results normalised to the dry mass are required, an oven or another suitable thermostatically

controlled heating chamber shall be used. The equipment shall be calibrated and capable of

maintaining the temperature needed to analyse the moisture content of the material with an

uncertainty that is at most 2 °C.
7.2.4 Equipment for particle size reduction and homogenisation

Mills and mixers should be used to reduce the particle size and homogenise the test portion, in

particular if the particle size of the initial material is > 6 mm.
7.2.5 Equipment recommended for handling dry powdered materials

It is recommended to use an ion blower or other type of equipment to reduce static electricity.

After the transfer of the test portion to the measurement container, a tapper or vibrating table

could be used to compact the test portion and equalise its height.
7.3 Gamma-ray spectrometry equipment

A gamma-ray spectrometer with high energy resolution (e.g. an HPGe) detector coupled to a pulse

processing, a data acquisition system and a computer shall be used to collect the spectra.

It is recommended to use detectors whose energy resolution (FWHM) is better than 2,2 keV (for

60 137

the Co peak at 1 332 keV) and with a peak/Compton ratio between 50 and 80 for Cs. For more

information, see IEC 61452 [13].
7.4 Containers to be used
7.4.1 Moisture content determination container

A container able to withstand the drying temperature shall be used. It shall be suitable for

containing a portion of a test sample required by the relevant ISO standard used for moisture

content determination without loss of sample material while permitting water to evaporate.

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7.4.2 Measurement container

Guidance information on a proper container for the test portion is given in ISO 20042.

If the measurement container is to be reused, it shall first be emptied, cleaned and checked for

radiopurity as it could have become contaminated by the previously measured test portion.

8 Procedure
8.1 Calibration
8.1.1 General

The gamma-ray spectrometry detector shall be calibrated for energy and peak detection

efficiency. The calibration should follow the requirements of IEC 61452 [13].
8.1.2 Energy calibration

The sources used for the energy calibration may be point sources of a single nuclide emitting

152

gamma rays of different energies (e.g. Eu), multiple nuclide point sources or a series of sources

containing radionuclides emitting one or more gamma rays.

Emphasis should be placed on the energy interval 364 keV to 796 keV, as the four main gamma

rays of the three radionuclides in the scope of this standard have energies in that interval.

8.1.3 Detection efficiency calibration

The counting detection efficiency for a gamma-ray energy is affected by five major factors:

— the intrinsic detector efficiency,
— the position of the source in relation to the detector,
— the physical dimensions of the measurement container,
— the density, matrix composition and the filling height of the test portion,

— the shield (indirectly by minimising interfering radiation or environmental background).

The experimental calibration of the detection efficiency should be performed using a reference

volume source (i.e. not a point source) measured in the same container and position as the test

portion. The properties of the reference volume source should be as similar as possible to those

of the test portion. To account for differences in their properties proper techniques for efficiency

transfer should be applied (see below).

As spiking may result in an inhomogeneous activity distribution preparation of a reference

volume source in the laboratory is only possible if a reliable and validated spiking procedure is

available. Blank material can be spiked with a multi-nuclide solution, several individual solutions

containing suitable radionuclides or a solution of a single nuclide emitting many gamma rays.

Attention should be paid to cover the region of interest (364 keV to 796 keV).
The net count rate (r ) shall be calculated using Formula (1).
N,E
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nn−×
NE,,b E
r =
NE,
(1)
is the net count rate in the full energy peak at energy E, in s ;
NE,

is the net number of counts in the peak, at energy E, in the test portion spectrum;

NE,

is the number of net counts in the peak, at energy E, in the background spectrum;

b,E
is the test portion spectrum live time, in s;
is the background spectrum live time, in s.
where
ε )

The detection efficiency at the energy E ( should be calculated according to Formula (2).

NE,
ε =
AP× ××f f
E d tcs,E
(2)
where

ε is the detection efficiency at energy E for the specific measurement geometry and

detector used;

is the net count rate in the full energy peak at energy E calculated using Formula (1);

NE,

A is the activity of the reference radionuclide emitting photons of energy E in the

calibration source, at the time of the calibration, in Bq;

P is the absolute probability of the emission of a photon with energy E, per decay;

is the factor to correct for decay between the reference time and the start of the

measurement and during the measurement;
is the factor to correct for true coincidence summing effects.
tcs,E

Once the detection efficiencies for the radionuclides present in the reference volume source are

calculated, they should be plotted against the energy of the emitted photon. Then, an efficiency

curve should be constructed by suitable fitting [2] (Figure 1).
...

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