CEN/TS 17216:2018
(Main)Construction products - Assessment of release of dangerous substances - Determination of activity concentrations of radium-226, thorium-232 and potassium-40 in construction products using semiconductor gamma-ray spectrometry
Construction products - Assessment of release of dangerous substances - Determination of activity concentrations of radium-226, thorium-232 and potassium-40 in construction products using semiconductor gamma-ray spectrometry
This document describes a test method for the determination of the activity concentrations of the radionuclides radium-226, thorium-232 and potassium-40 in construction products using semiconductor gamma-ray spectrometry.
This document describes sampling from a laboratory sample, sample preparation, and the sample measurement by semiconductor gamma-ray spectrometry. It includes background subtraction, energy and efficiency calibration, analysis of the spectrum, calculation of the activity concentrations with the associated uncertainties, the decision threshold and detection limit, and reporting of the results. The preparation of the laboratory sample from the initial product sample lies outside its scope and is described in product standards.
This document is intended to be non product-specific in scope, however, there are a limited number of product-specific elements such as the preparation of the laboratory sample and drying of the test portion. The method is applicable to samples from products consisting of single or multiple material components.
Bauprodukte - Bewertung der Freisetzung von gefährlichen Stoffen - Messung der spezifischen Aktivität von Radium-226, Thorium-232 und Kalium-40 in Bauprodukten mittels Halbleiter-Gammaspektrometrie
Dieses Dokument beschreibt ein Prüfverfahren zur Bestimmung der spezifischen Aktivitäten der Radionuklide Radium-226, Thorium-232 und Kalium-40 in Bauprodukten durch Halbleiter-Gammaspektrometrie.
Dieses Dokument beschreibt die Probenahme einer Laborprobe, die Probenvorbereitung und die Messung der Probe durch Halbleiter-Gammaspektrometrie. Dazu gehört die Hintergrundsubtraktion, Energie- und Effizienzkalibrierung, Analyse des Spektrums, Berechnung der spezifischen Aktivitäten mit den zugehörigen Unsicherheiten, der Erkennungsgrenze und Nachweisgrenze und Angabe der Prüfergebnisse. Die Vor-bereitung der Laborprobe aus der ursprünglichen Produktprobe liegt außerhalb des Anwendungsbereichs und wird in den Produktnormen beschrieben.
Dieses Dokument soll in ihrem Anwendungsbereich nicht produktspezifisch sein, allerdings gibt es eine begrenzte Anzahl produktspezifischer Elemente, wie die Vorbereitung der Laborprobe und die Trocknung der Prüfmenge. Das Verfahren eignet sich für Produktproben, die aus einzelnen oder multiplen Material-komponenten bestehen.
Produits de construction - Evaluation de l'émission de substances dangereuses - Détermination de l’activité du radium-226, du thorium-232 et du potassium-40 dans les produits de construction par spectrométrie gamma
Gradbeni proizvodi - Ocenjevanje sproščanja nevarnih snovi - Določevanje koncentracije aktivnosti radija Ra-226, torija Th-232 in kalija K-40 v gradbenih proizvodih s polprevodniško gama spektrometrijo
Ta tehnična specifikacija določa metodo za določevanje koncentracije aktivnosti radionuklidov 226Ra, 232Th in 40K v gradbenih proizvodih s polprevodniško gama spektrometrijo. Standard opisuje vzorčenje, pripravo preskusnih vzorcev in izvedbo preskusa. Vključuje odstranjevanje ozadja, umerjanje energije in učinkovitosti, analizo spektra, izračun koncentracije aktivnosti s povezanimi negotovostmi, prag odločanja in omejitev zaznavanja ter objavo rezultatov.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2019
*UDGEHQLSURL]YRGL2FHQMHYDQMHVSURãþDQMDQHYDUQLKVQRYL'RORþHYDQMH
NRQFHQWUDFLMHDNWLYQRVWLUDGLMD5DWRULMD7KLQNDOLMD.YJUDGEHQLK
SURL]YRGLKVSROSUHYRGQLãNRJDPDVSHNWURPHWULMR
Construction products - Assessment of release of dangerous substances - Determination
of activity concentrations of radium-226, thorium-232 and potassium-40 in construction
products using semiconductor gamma-ray spectrometry
Bauprodukte - Bewertung der Freisetzung von gefährlichen Stoffen - Messung der
spezifischen Aktivität von Radium-226, Thorium-232 und Kalium-40 in Bauprodukten
mittels Halbleiter-Gammaspektrometrie
Produits de construction - Evaluation de l'émission de substances dangereuses -
Détermination de l’activité du radium-226, du thorium-232 et du potassium-40 dans les
produits de construction par spectrométrie gamma
Ta slovenski standard je istoveten z: CEN/TS 17216:2018
ICS:
13.020.99 Drugi standardi v zvezi z Other standards related to
varstvom okolja environmental protection
17.240 Merjenje sevanja Radiation measurements
91.100.01 Gradbeni materiali na Construction materials in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN/TS 17216
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
October 2018
TECHNISCHE SPEZIFIKATION
ICS 91.100.01
English Version
Construction products - Assessment of release of
dangerous substances - Determination of activity
concentrations of radium-226, thorium-232 and
potassium-40 in construction products using
semiconductor gamma-ray spectrometry
Produits de construction - Evaluation de l'émission de Bauprodukte - Bewertung der Freisetzung von
substances dangereuses - Détermination de l'activité gefährlichen Stoffen - Messung der spezifischen
du radium-226, du thorium-232 et du potassium-40 Aktivität von Radium-226, Thorium-232 und Kalium-
dans les produits de construction par spectrométrie 40 in Bauprodukten mittels Halbleiter-
gamma Gammaspektrometrie
This Technical Specification (CEN/TS) was approved by CEN on 14 May 2018 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of 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, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17216:2018 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 8
5 Principles of the test method . 11
6 Sampling and sample preparation . 11
6.1 Sampling hierarchy . 11
6.2 Sampling and sub-sampling . 14
6.3 Test specimen/test portion preparation . 14
7 Test procedure . 18
7.1 General . 18
7.2 Measurement . 18
8 Processing the test data . 21
8.1 General . 21
8.2 Analysis of counting spectrum . 22
8.3 Calculating activity concentration . 22
8.4 Standard uncertainty . 24
8.5 Decision threshold . 27
8.6 Detection limit . 27
9 Test report . 29
Annex A (normative) Method for the determination of the radon-tightness of a test
specimen container . 31
A.1 Principle . 31
A.2 Apparatus, equipment and reagents . 31
A.3 Test . 31
A.4 Processing experimental data . 32
Annex B (normative) Preparation of standardized calibration sources . 35
B.1 Principle . 35
B.2 Apparatus, equipment and reagents . 35
B.3 Test . 35
Annex C (normative) Method for the determination of the activity concentration in a
composite product . 39
Annex D (informative) Complementary photopeaks to verify the activity concentration in
the test specimen . 40
Annex E (informative) Method for the determination of the corrected number of pulses in a
photopeak (only to be used for completely stand-alone single peaks) . 41
Bibliography . 42
European foreword
This document (CEN/TS 17216:2018) has been prepared by Technical Committee CEN/TC 351
“Construction products - Assessment of release of dangerous substances”, the secretariat of which is
held by NEN.
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 mandate 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 announce this Technical Specification: 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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
This document is a Technical Specification developed under Mandate M/366 issued by the European
Commission in the framework of the “Construction Products Directive” 89/106/EEC. This document
addresses the part of Mandate M/366 which provides for the preparation of horizontal
measurement/test methods for the determination of the activity concentrations of the radionuclides
radium-226, thorium-232 and potassium-40 in construction products using gamma-ray spectrometry.
Mandate M/366 is a complement to the product mandates issued by the European Commission to CEN
under the Construction Products Directive (CPD). The harmonized product standards (hEN) developed
in CEN under mandates (and ETAs developed in EOTA for products or kits) specify construction
product(s) as placed on the market and address their intended conditions of use.
The information produced by applying this Technical Specification can be used for purposes of CE
marking and evaluation/attestation of conformity. Product specification, standardization of
representative sampling and procedures for any product-specific laboratory sample preparation are the
responsibility of product TCs and are not covered in this Technical Specification.
This Technical Specification supports existing regulations and standardized practices, and is based on
methods described in standards, such as ISO 10703 [1], ISO 18589-2 [2], ISO 18589-3 [3] and NEN 5697
[4]. In summary, the Technical Specification describes the following:
— sampling, sub-sampling and test specimen preparation;
— measurement using gamma-ray spectrometry;
— background subtraction, energy and efficiency calibration, analysis of the spectrum;
— calculation of activity concentrations with associated uncertainties;
— reporting of test results.
Determination of the activity concentration is based on the principles of gamma-spectrometry, and
procedures for all stages of the testing are provided in this document. Although the tested material
sample rarely reflects a product’s form under its intended conditions of use, the measured activity
concentration is an intrinsic property of the material, which does not vary with the construction
product’s form. Consequently, the test results reflect the radiation behaviour of the product under its
intended use. In addition, the Technical Specification is intended to be non product-specific in scope,
with only a limited number of product-specific elements.
1 Scope
This document describes a test method for the determination of the activity concentrations of the
radionuclides radium-226, thorium-232 and potassium-40 in construction products using
semiconductor gamma-ray spectrometry.
This document describes sampling from a laboratory sample, sample preparation, and the sample
measurement by semiconductor gamma-ray spectrometry. It includes background subtraction, energy
and efficiency calibration, analysis of the spectrum, calculation of the activity concentrations with the
associated uncertainties, the decision threshold and detection limit, and reporting of the results. The
preparation of the laboratory sample from the initial product sample lies outside its scope and is
described in product standards.
This document is intended to be non product-specific in scope, however, there are a limited number of
product-specific elements such as the preparation of the laboratory sample and drying of the test
portion. The method is applicable to samples from products consisting of single or multiple material
components.
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 edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 16687:2015, Construction products - Assessment of release of dangerous substances - Terminology
ISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the
confidence interval) for measurements of ionizing radiation - Fundamentals and application
ISO IEC Guide 98-3, Uncertainty of measurement - Part 3: Guide to the expression of uncertainty in
measurement (GUM, 1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
blank
volume of demineralized or distilled water that corresponds to the volume and geometry of the test
specimen
3.2
calibration source
sample with known radioactivity concentration and material properties that corresponds to the volume
and geometry of the test specimen
[SOURCE: EN 16687:2015, 4.4.2]
3.3
composite sample
sample that consist of two or more material components, put together in appropriate portions, from
which the mean value of a desired characteristic may be obtained
[SOURCE: EN 16687:2015, 3.1.1; modified to read 'material components' instead of 'increments']
3.4
crushed material
sample material prepared by crushing a portion of the laboratory sample
[SOURCE: EN 16687:2015, 4.4.4]
3.5
dead time
time during which the measurement system is actually processing the signal and is not able to accept
the next signal
[SOURCE: EN 16687:2015, 4.4.3]
3.6
laboratory sample
sample or sub-sample(s) sent to or received by the laboratory
[SOURCE: EN 16687:2015, 3.2.1]
Note 1 to entry: When the laboratory sample is further prepared by subdividing, cutting, sawing, coring, mixing,
drying, grinding, and curing or by combinations of these operations, the result is the test sample. When no
preparation of the laboratory sample is required, the laboratory sample is the test sample. A test portion is
removed from the test sample for the performance of the test/ analysis or for the preparation of a test specimen.
Note 2 to entry: The laboratory sample is the final sample from the point of view of sample collection but it is
the initial sample from the point of view of the laboratory.
3.7
product sample
construction product taken in whole or in part at the factory, on the market or on the construction site
representative of the construction product
[SOURCE: EN 16687:2015, 3.1.4]
3.8
test portion
amount of the test sample taken for testing/ analysis purposes, usually of known weight or volume
[SOURCE: EN 16687:2015, 3.2.3]
3.9
test sample
sample, prepared from the laboratory sample from which test portions are removed for testing or for
analysis
[SOURCE: EN 16687:2015, 3.2.2]
3.10
test specimen
test portion specially prepared for testing in a test facility in order to simulate the radiation behaviour
of the product under intended conditions of use
[SOURCE: EN 16687:2015, 3.2.4]
3.11
test specimen container
holder shaped like a beaker or a vessel that can be sealed and that is used to make determinations on
the test specimen
[SOURCE: EN 16687:2015, 4.4.5]
4 Symbols and abbreviations
For the purposes of this document, the following symbols, names of quantities and units apply.
Symbol Name of quantity Unit
a, b, c free parameters used in an e-power formula –
A the activity of the standardized calibration source j at energy E Bq
i;j i
b ordinal –
the average activity concentration of radionuclide i Bq/kg
C
i
C the activity concentration of radionuclide i in the test specimen k Bq/kg
i;k
# is the detection limit of radionuclide i of test specimen k Bq/kg
C
ik;
* is the decision threshold of radionuclide i of test specimen k Bq/kg
C
ik;
E energy used for determining radionuclide i keV
i
f ordinal –
i ordinal –
j ordinal –
k ordinal –
k the uncertainty coverage factor –
k the uncertainty coverage factor with a default value of 1,65 at α = 0,05 –
1−α
k the uncertainty coverage factor with a default value of 1,65 at β = 0,05 –
1−β
m the mass of matrix material j kg
j;mat
m the mass of sub sample k of standardized material j kg
j;k;stand
m the mass of the test specimen k kg
k
n number of test specimens –
N the corrected number of pulses in the photopeak –
N the number of pulses collected in channel q –
q
Symbol Name of quantity Unit
the average number of pulses per channel before the peak –
N
b
the average number of pulses per channel after the peak –
N
f
N the net number of pulses in the photopeak that corresponds to energy E of –
i;j i
standardized calibration source j
N the number of pulses that is collected in the continuum under the photopeak when –
cont;k
counting the test specimen k
N the number of pulses that is collected in the continuum under the photopeak with –
cont;i;j;mat
energy Ei of matrix material j
Ncont;i;j;k;stand the number of pulses that is collected in the continuum under the photopeak with –
energy Ei of sub sample k of standardized material j
Ntot;i;j;mat the total number of pulses that is collected in the channels belonging to the –
photopeak with energy Ei of matrix material j
Ntot;i;j;k;stand the total number of pulses that is collected in the channels belonging to the –
photopeak with energy Ei of sub sample k of standardized material j
Ntot;k the total number of pulses that is collected in the channels belonging to the –
photopeak when counting the test specimen k
p ordinal –
q ordinal –
-1
R the counting rate of the blank that is determined from the number of pulses that is s
cont;0
collected in the continuum under the photopeak
-1
R the counting rate of the test specimen k that is determined from the number of pulses s
cont;k
that is collected in the continuum under the photopeak
-1
R the counting rate in spectrum w that is determined from the number of pulses that is s
cont;w
collected in the continuum under the photopeak
-1
R the corrected counting rate of the blank s
cor;0
-1
R the corrected specific counting rate of matrix material j at energy E (s·kg)
cor;i;j;spec;mat i
-1
Rcor;i;j;spec;stand the average specific corrected counting rate of all subsamples k of (s·kg)
standardized material j at energy E
i
-1
R the corrected specific counting rate of sub sample k of standardized material jat (s·kg)
cor;i;j;k;spec;stand
energy E
i
-1
R the corrected counting rate of the test specimen k that is determined for the s
cor;k
photopeak
-1
R the corrected counting rate in spectrum w that is determined for the photopeak s
cor;w
-1
Rtot;0 the total counting rate of the blank that is determined from the total number of pulses s
that is collected in the channels belonging to the photopeak
-1
Rtot;k the total counting rate of the test specimen k that is determined from the total s
number of pulses that is collected in the channels belonging to the photopeak
-1
Rtot;w the total counting rate in spectrum w that is determined from the total number of s
pulses that is collected under the photopeak
S the total radon production in the building material Bq/s
t the counting time s
Symbol Name of quantity Unit
t the counting time of the blank corrected for the dead time s
t the counting time of the calibration source j corrected for the dead time s
j
tj;mat the counting time of matrix material j corrected for the dead time s
tj;k;stand the counting time of sub sample k of standardized material j corrected for the dead s
time
tk the counting time of the test specimen k corrected for the dead time s
tw the counting time of the gas sample in spectrum w corrected for the dead time s
-1
u the uncertainty is the uncertainty in the free parameter a of the radon-tightness test s
a
u the external uncertainty of the mass activity of radionuclide i Bq/kg
i;ext
ui;ie is the internal or external uncertainty of the activity of radionuclide i Bq/kg
ui;int the internal uncertainty of the mass activity of radionuclide i Bq/kg
u the uncertainty of radionuclide i of the test specimen k Bq/kg
i;k
u the total uncertainty of the activity of radionuclide i Bq/kg
i,tot
u(Rcor;w) the uncertainty of the corrected counting rate Rcor;w Bq/kg
V the volume m
w ordinal –
α the probability of a first order error with a default value of 0,05 –
β the probability of a second order error with a default value of 0,05 –
-1
εi;j the radionuclide-specific counting efficiency for energy Ei and the standardized (Bq·s)
calibration source j
-1
εi;k the radionuclide-specific counting efficiency for energy Ei and a counting (Bq·s)
sample with mass m
k
ηk the correction factor for dry mass of the test specimen k –
-1
λl the tightness of a test specimen container s
-1
λ the decay constant of radon-222 s
Rn
ν the coefficient of variation of the corrected specific counting rate of –
i;j;ext
sub sample k of standardized material j at energy Ei
ν the coefficient of variation due to radon-222 leakage from the test specimen –
i;l
container
ν the total relative uncertainty of the activity of radionuclide i –
i,tot
ν the relative uncertainty in the counting efficiency of radionuclide i –
i;ε
νi;ρ the relative uncertainty in the density correction of radionuclide i –
5 Principles of the test method
The activity concentrations of the gamma-emitting radionuclides in construction products are
determined using gamma-ray spectrometry. Activity concentration is a material-property and not a
function of the physical form of a construction product.
The activity of gamma-emitting radionuclides present in the test specimen is based on the analysis of
the energies and the peak areas obtained from the full-energy peaks of the gamma lines that allow the
identification and the quantification of the radionuclides.
The test method requires accurate energy and efficiency calibrations. Such calibration is performed
using a calibration material with a known activity source that is similar in chemical composition and
density to the materials that are to be tested. The calibration is based on a pre-selected set of
photopeaks used for the determination of the activity concentration. Selected photopeaks are either
emitted by the radionuclide itself or by one of its progeny nuclides.
The activity concentration is measured using a homogeneous, mostly granular, test specimen held in a
container with a predefined geometry. This determination, requiring as it does a test specimen of
granular material to be presented to the spectrometer, will only rarely reflect a product's form under its
intended conditions of use. Nevertheless, because the activity concentration is an intrinsic material
property, the test results will simulate the radiation behaviour of the product under its intended
conditions of use.
For radium-226 and thorium-232 the activity concentration is determined using a progeny nuclide,
while for potassium-40 the concentration is based on the photopeak from the nuclide itself. In those
cases where the activity is determined using a progeny nuclide, a secular equilibrium between the
progeny nuclide and its originating nuclide is necessary. To reach such equilibrium the test specimen is
stored in a radon-tight container for a period of at least three weeks in order to ensure there is no
degradation in the equilibrium due to a leakage of radon activity.
Despite the required waiting time of three weeks a disequilibrium in the thorium-232 decay chain can
be present. Such disequilibrium is caused by different dissolution ratios between thorium and radium,
particular hydrogeological history and effects of industrial processes. In case of such disequilibrium the
thorium-232 activity is approximated.
NOTE 1 Thorium-232 with a half-life of 1,41 × 10 years is the parent nuclide of the thorium decay chain.
Thorium-232 has a line at 63,81 keV with a very low emission probability of 0,263 % which overlaps a line of
thorium-234 at 63,28 keV with a higher emission probability of 4,1 %, so that thorium-232 cannot be determined
directly by gamma spectrometry. Determination through its decay radionuclides actinium-228, lead-212 and
thallium-208 can be performed only if one assumes that these radionuclides are in radioactive equilibrium with
thorium-232.
NOTE 2 Where the activity concentration between thorium-228 and radium-228 is considerably different
alternative measurement techniques or procedures to determine the thorium-232 more accurately are available
but are outside the scope of this document.
6 Sampling and sample preparation
6.1 Sampling hierarchy
A diagram of the sampling hierarchy (Figure 1) is presented and followed by a sketch with a physical
description of the samples (Figure 2) in support of the relevant definitions given in Clause 3.
NOTE The test method described in this Technical Specification starts with a laboratory sample received by
the laboratory. The preparation of a product sample lies outside the scope of this Technical Specification and is
described in product standards.
Figure 1 — Diagram of the sample hierarchy
Key
1 sampling
a) Product sample – sample of a construction product
b) Composite sample – sample consisting of a number of components
Key
1 laboratory
c) Laboratory sample – sample sent to or received by the laboratory
d) Test sample – sample to provide material for all analytical testing
e) Test portion – sample for general analytical testing
f) Test specimen – sample for radiation testing
Figure 2 — Sketch of the samples with a physical description
6.2 Sampling and sub-sampling
6.2.1 General
The method starts with a laboratory sample received by the laboratory. The preparation of a product
sample lies outside the scope of this Technical Specification.
The following items listed below should be taken into account:
a) For general guidance on sampling and sampling procedures for the making of a laboratory sample
reference should be made to CEN/TR 16220 [5];
b) For composite construction products, a product sample containing all of the material components
can be put forward for testing. Alternatively, each of the components can be sent for testing
individually. In that case the activity concentration of the construction product is calculated using
the procedures described in Annex C;
c) For composite products where blending of the various material components results in a change of
material composition or loss of weight the calculation of the mean activity concentration based on
the individual components may deviate from that of the composite material;
d) Where preparation of a cement-based concrete product sample from fresh, wet concrete is
required, reference should be made to the sampling procedures in EN 12350-1 [6] and the
production of hardened specimens in EN 12390-2 [7]. These procedures are additional to the
sampling procedures described in CEN/TR 16220 [5].
A random portion of the laboratory sample is crushed to make a test sample; for those materials
described in 6.3.2.1, no crushing is needed. From the test sample, test portions are taken for general
analytical testing and as a test specimen on which to perform radiation testing.
6.2.2 Sub-sampling from the laboratory sample
Randomly take some sub-samples from the laboratory sample. The random sub-samples together shall
contain sufficient material to prepare a minimum of one test specimen and a test portion for general
analytical testing.
6.3 Test specimen/test portion preparation
6.3.1 Apparatus and ancillary materials
6.3.1.1 Crushing apparatus, used to obtain a test sample with particle sizes of no more than 5 mm.
6.3.1.2 Sieve, with apertures which retain particles of more than 5 mm.
6.3.1.3 Calibrated balances.
6.3.1.3.1 Balance No. 1, with measurement uncertainty not more than 0,1 % and reading
uncertainty not more than 1 g.
6.3.1.3.2 Balance No. 2, with measurement uncertainty not more than 0,1 % and reading
uncertainty not more than 0,01 g.
6.3.1.4 Test specimen container, suited for gamma spectrometry with a preselected volume and
geometry. The container should have the following characteristics:
a) be made of materials impermeable to radon;
b) be made of materials with low absorption of gamma radiation;
c) preferably have volumes adapted to the shape of the detector for maximum efficiency;
d) be watertight and not react with the specimen components/constituents;
e) have a wide-necked opening to facilitate filling;
f) be unbreakable.
In order to verify easily that the content of the container conforms to the standard counting geometry, a
transparent container with a mark to check the filling can be selected.
When selecting an appropriate container geometry, it should be considered that Marinelli beakers are
recommended for coaxial detectors. For planar detectors, e.g. broad energy detectors, cylindrical
geometries are recommended. Alternatively, multiple containers can be selected to cover for a wide
range of densities and expected activity concentrations. However, in that case a separate calibration for
each container is required. Furthermore, maximising detector efficiency and representativeness of the
test specimen, should be considered when choosing an appropriate container volume. When selecting a
polymer based container it should be considered that polymer materials suitable for use include: high
density polyethylene (HDPE) and polyethylene terephthalate (PET). Note that Marinelli beakers are
also made from polypropylene (PP), which is not always radon impermeable.
6.3.1.5 Closing lid, that can be used to cover the test specimen container without any air pockets
after it is filled with the test specimen.
6.3.1.6 Sealant, for example, acrylic paste, a two-component epoxy adhesive, or a wide insulation
tape with surface degreaser.
6.3.1.7 Test beaker, for determination of dry matter content, with a volume of not more than
250 ml.
6.3.2 Preparation of test portion and test specimen
6.3.2.1 General
Laboratory samples, or sub-samples taken there from, require no further preparation, where they are:
— homogeneous in terms of chemical composition and activity concentration, and the test sample
geometry fits the test specimen container appropriately;
— granular (e.g. cement, fly-ash, powdered gypsum, etc.), or;
— flexible (e.g. mineral wool, etc.).
In all other cases, the test samples shall be prepared by crushing, as follows:
a) Prepare test samples by crushing to a maximum particle size of no more than 5 mm.
NOTE Crushing can be carried out using for example a mortar or a ball mill.
If sample units are too large for the crushing apparatus, take a representative sub-sample and
break the units into smaller pieces using appropriate means which do not introduce contamination
and crush this sub-sample. Ideally, dry procedures for such size reduction are preferred but the use
of wet-sawing is permitted. In this case, dry the samples until the dry mass is obtained in a similar
way as given in 6.3.2.2 and 7.2.3.3 before performing the test.
b) Sieve the crushed material.
c) Homogenize the crushed material.
6.3.2.2 Test specimen for determination of activity concentration
Prepare a minimum of one test specimen in the following manner.
If there are indications that the activity might not be uniformly distributed in the test sample, or in the
test specimen itself it is recommend to prepare a minimum of three test specimens. This can be for
example the case if the activity is not uniformly distributed along the range of particle sizes.
a) Choose the container that is best suited to the volume of the sample so as to measure emissions
from as much material as possible. To decrease self-absorption effects, the height of the content
should be minimized. The container geometry used for testing shall be identical with the geometry
used for calibration, and the radon-tightness shall be determined in accordance with Annex A.
b) Weigh the empty test specimen container.
c) Determine the volume of the test specimen:
1) Add water to the empty test specimen container up to the same level as during testing and
calibration.
2) Weigh the test specimen container plus water.
3) The numerical value of the volume of the test specimen container in litres equals the numerical
value of the mass in kg of the test specimen container plus water minus the mass of the empty
test specimen container.
4) Empty the test specimen container and dry it.
Determination of the volume is only required when the test specimen container is used for the
first time.
d) Fill the test specimen container.
It is permitted to dry the test specimen before filling the container in accordance with the
requirements for drying as described in 7.2.3.3. In that case no correction for dry weight should be
applied to the activity concentrations and the preparation of a test portion as described in 6.3.2.2
and the subsequent drying described in 7.2.3.3 is not applicable.
1) Add the test specimen to the container incrementally up to the same level as during calibration.
2) Vibrate the test specimen container or carefully tap the test specimen container after addition
of each increment. It is recommended to use a mechanical compacting device (for example, a
vibrating table) to compact samples to the same degree in order to achieve a fairly constant
compacted volume.
3) Weigh the test specimen container plus test specimen and obtain the mass of the test specimen
by subtracting the mass of the container.
e) Place the lid on, or in, the test specimen container such that it is resting on the material.
NOTE 1 Figure 3 shows various examples of container shapes and lids.
Figure 3 — Sketch of various test specimen containers with lid and crushed material
f) Clean the outside of the container to remove any excess material left adhering from the filling
process.
g) Seal the lid to the test specimen container so that it is radon-tight.
Sealing the edges where they join the lid on the test specimen container has proven to be suitable.
Before sealing, ensure the corresponding surfaces of the container and the lid are degreased. Then
glue or use an insulation tape. In case of insulating tape use 3 layers (without wrinkles) tightly
glued along the perimeter of the container-lid joint.
h) Store the test specimen in the container for at least three weeks before performing the test.
NOTE 2 This period is necessary to allow radon-222 and its progeny to equilibrate with its parent nuclide
radium-226.
6.3.2.3 Test portion for determination of dry matter content
Prepare a single test portion in the following manner if the test specimen contains wet material.
Preparation of a test portion and determination of the dry matter content is not applicable when the
test specimen is dried in accordance with the requirements described in 7.2.3.3.
a) Weigh the empty test beaker to the nearest 0,1 g.
b) Add approximately 100 g of the test portion to the test beaker.
c) Weigh the test beaker plus test portion to the nearest 0,1 g.
d) Obtain the mass of the test portion by subtracting the mass of the test beaker from the combined
mass of the beaker plus test portion.
e) Without delay, carry out the determination of the dry matter content in accordance with 7.2.3.3.
7 Test procedure
7.1 General
The gamma radiation emitted from the test specimen is counted using a semiconductor detector with
high energy resolution in combination with a pulse sorting device (multichannel analyser, MCA).
Subsequently the pulse height of the various energy lines in the spectrum is analysed.
The test measurements are carried out in accordance with 7.2.
7.2 Measurement
7.2.1 Apparatus, software and calibration standards
7.2.1.1 Standardized calibration sources, at least four prepared in accordance with Annex B.
7.2.1.2 Energy calibration source(s), one or more.
7.2.1.3 Drying oven, capable of maintaining temperature at the set point to within ± 2 ºC.
7.2.1.4 Semiconductor detector, with a cooling system consisting of a germanium detector (Ge(Li)
or ‘high purity’ Ge) with cryostat, preamplifier and main amplifier with suitable possibilities for pulse
formation and baseline recovery.
NOTE 1 The detector cap can be covered with, for example, polyethylene foil to protect the detector against
contamination. The polyethylene foil can be easily exchanged should contamination take place.
NOTE 2 Guidance on testing and using the germanium detector is given in IEC 60973 [8], IEC 61151 [9] and
IEC 61452 [10].
7.2.1.5 Shielding for the detector, the detector shall be shielded on all sides including the bottom,
both to reduce the background signal and to maintain it at a low constant level.
NOTE It is important that the background signal is not just low but, in particular, also constant. A variable
background signal can be caused by the presence of radon or radon progeny in the air as well as other reasons.
For the analysis of low radioactivity, it may therefore be necessary to ventilate the assembly itself and the room
where it has been set up. Ventilation of the assembly can be carried out using nitrogen gas.
7.2.1.6 Electronics, should consist of:
a) high-voltage power supply;
b) signal amplification system;
c) an analogue-to-digital converter.
7.2.1.7 Sorting equipment, capable of sorting successive signal pulses (multichannel analyser
(MCA)). Sorter with at least 4 096 channels.
NOTE Pulse sorting equipment is readily available with 16 000 or more channels.
7.2.1.8 Data processing software, for analysing complex spectra on a multiple number of
radionuclides.
7.2.1.8.1 Operational characteristics of the software, the pulse sorting device should be linked to
some computing equipment capable of doing the following:
a) read, save in a memory and reproduce on a printer or plotter a spectrum in combination with the
various variables (identification of the test specimen, date and counting time);
b) trace peaks, determine peak width, the centroid and the net number of pulses in the photopeak and
display the associated errors and fit parameters;
c) perform the energy calibration (which relates the channel numbers to the respective energies)
using one or more calibration sources;
d) identify the radionuclides present based on the energies of the found peaks;
e) calculate the counting efficiency, the counting time corrected for the dead time, the activity present
in relation to the coefficient of variation, decision threshold and the lowest detectable activity
based on the calculated net number of pulses in the photopeak.
7.2.1.8.2 Validation of the software, before using the software in routine operations, a check shall
be performed on the numeric results. It is, in particular, important to verify whether the method used to
determine the continuum under a photopeak and the method used to analyse the peaks using a small
number of counting pulses provides accurate results. It is recommended that, during routine use, a
visual check and critical evaluation is performed on the results provided by the software especially in
relation to qualitative aspects. It is also recommended that the same software is used for the evaluation
of the spectra from the test samples and for the evaluation of the calibration spectra.
Computer software that can analyse gamma spectra is readily available and is often supplied in
combination with the counting facility. Available software ranges from simple to extremely advanced
and it is recommended that its quality is additionally validated by participation in interlaboratory
comparisons and/or in recognized proficiency testing schemes.
7.2.2 Initial calibrations
7.2.2.1 Energy calibration of the gamma spectrometer
Place one or more energy calibration sources in the measuring facility and configure the amplifier in
such a way that the first channel matches to an energy level between 0 keV and 50 keV. In addition,
adjust, the amplifier to ensure that the energ
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