ISO/ASTM 51707:2015

Guide for estimation of measurement uncertainty in dosimetry for radiation processing

ISO/ASTM 51707:2015 provides guidance on the use of concepts described in the JCGM Evaluation of Measurement Data ? Guide to the Expression of Uncertainty in Measurement (GUM) to estimate the uncertainties in the measurement of absorbed dose in radiation processing. Methods are given for identifying, evaluating and estimating the components of measurement uncertainty associated with the use of dosimetry systems and for calculating combined standard measurement uncertainty and expanded (overall) uncertainty of dose measurements based on the GUM methodology. Examples are given on how to develop a measurement uncertainty budget and a statement of uncertainty. ISO/ASTM 51707:2015 is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation processing, and provides guidance for achieving compliance with the requirements of ISO/ASTM 52628 related to the evaluation and documentation of the uncertainties associated with measurements made with a dosimetry system. It is intended to be read in conjunction with ISO/ASTM 52628, ISO/ASTM 51261 and ISO/ASTM 52701.

Guide pour l’estimation de l’incertitude de mesure en dosimétrie pour le traitement par irradiation

General Information

• Status: Published
• Publication Date: 16-Mar-2015
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 04-Jun-2020

Relations

• Revises: ISO/ASTM 51707:2005 - Guide for estimating uncertainties in dosimetry for radiation processing
• Effective Date: 07-Jun-2014

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51707
Third edition
2015-03-15
Guide for estimation of measurement un-
certainty in dosimetry for radiation pro-
cessing
Guide pour l’estimation de l’incertitude de mesure en dosimétrie
pour le traitement par irradiation
Reference number
ISO/ASTM 51707:2015(E)
© ISO/ASTM International 2015

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ISO/ASTM 51707:2015(E)
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Published in Switzerland
ii © ISO/ASTM International 2015 – All rights reserved

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ISO/ASTM 51707:2015(E)
Contents Page
1 Scope. 1
2 Referenced documents. 1
3 Terminology. 2
4 Significance and use. 4
5 Basic concepts—components of uncertainty. 4
6 Evaluation of Type A and Type B standard uncertainty. 4
7 Examples of uncertainty budget components associated with absorbed dose measurements. 5
8 Characterization of uncertainty components based on probability distributions. 6
9 Statement of uncertainty. 8
10 Uses of measurement uncertainty estimates . 8
11 Keywords. 9
Annexes. 9
Bibliography. 11
Figure1 Normal distribution, also called Gaussian or “bell curve”, the most important continuous
random distribution (JCGM 100:2008) . 7
Figure 2 Rectangular distribution, also called continuous uniform distribution (JCGM 100:2008). 7
Table A2.1 . 10
Table A2.2 . 11
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ISO/ASTM 51707:2015(E)
Foreword
ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to the member bodies for
voting. Publication as an International Standard requires approval by at least 75% of the member bodies
casting a vote.
ASTM International is one of the world’s largest voluntary standards development organizations with global
participation from affected stakeholders. ASTM technical committees follow rigorous due process balloting
procedures.
A project between ISO and ASTM International has been formed to develop and maintain a group of
ISO/ASTM radiation processing dosimetry standards. Under this project, ASTM Committee E61, Radiation
Processing, is responsible for the development and maintenance of these dosimetry standards with
unrestricted participation and input from appropriate ISO member bodies.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. Neither ISO nor ASTM International shall be held responsible for identifying any or all such patent
rights.
International Standard ISO/ASTM 51707 was developed by ASTM Committee E61, Radiation Processing,
through Subcommittee E61.01, Dosimetry, and by Technical Committee ISO/TC 85, Nuclear energy, nuclear
technologies and radiological protection.
This third edition cancels and replaces the second edition (ISO/ASTM 51707:2005), which has been
technically revised.
iv © ISO/ASTM International 2015 – All rights reserved

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ISO/ASTM 51707:2015(E)
An American National Standard
Standard Guide for
Estimation of Measurement Uncertainty in Dosimetry for
1
Radiation Processing
This standard is issued under the fixed designation ISO/ASTM 51707; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This standard provides guidance on the use of concepts
described in the JCGM Evaluation of Measurement Data –
2. Referenced documents
Guide to the Expression of Uncertainty in Measurement
2
(GUM) to estimate the uncertainties in the measurement of
2.1 ASTM Standards:
absorbed dose in radiation processing.
E170 Terminology Relating to Radiation Measurements and
1.2 Methods are given for identifying, evaluating and esti- Dosimetry
mating the components of measurement uncertainty associated E456 Terminology Relating to Quality and Statistics
with the use of dosimetry systems and for calculating com- 2
2.2 ISO/ASTM Standards:
bined standard measurement uncertainty and expanded (over-
51261 Practice for Calibration of Routine Dosimetry Sys-
all) uncertainty of dose measurements based on the GUM
tems for Radiation Processing
methodology.
51608 Practice for Dosimetry in an X-Ray (Bremsstrahlung)
1.3 Examples are given on how to develop a measurement
Facility for Radiation Processing
uncertainty budget and a statement of uncertainty.
51649 Practice for Dosimetry in an Electron Beam Facility
for Radiation Processing at Energies Between 300 keV
1.4 This document is one of a set of standards that provides
and 25 MeV
recommendations for properly implementing dosimetry in
51702 Practice for Dosimetry in a Gamma Facility for
radiation processing, and provides guidance for achieving
Radiation Processing
compliancewiththerequirementsofISO/ASTM52628related
52628 Practice for Dosimetry in Radiation Processing
to the evaluation and documentation of the uncertainties
52701 Guide for Performance Characterization of Dosim-
associated with measurements made with a dosimetry system.
eters and Dosimetry systems for Use in Radiation Pro-
ItisintendedtobereadinconjunctionwithISO/ASTM52628,
cessing
ISO/ASTM 51261 and ISO/ASTM 52701.
2.3 ISO Documents:
1.5 Thisguidedoesnotaddresstheestablishmentofprocess
specifications or conformity assessment. ISO 11137-1 Sterilization of Health Care Products – Radia-
tion – Requirements for Development, Validation and
1.6 This standard does not purport to address all of the
3
Routine Control of a Sterilization Process
safety concerns, if any, associated with its use. It is the
ISO/IEC 17025 General Requirements for the Competence
responsibility of the user of this standard to establish appro-
4
of Testing and Calibration Laboratories
1
This guide is under the jurisdiction of ASTM Committee E61 on Radiation
2
Processing and is the direct responsibility of Subcommittee E61.01 on Dosimetry, For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
and is also under the jurisdiction of ISO/TC 85/WG 3. www.astm.org, or contact ASTM Customer Service at [e-mail]. For
Current edition approved by ASTM Sept. 8, 2014. Published February 2015. Annual Book of ASTM Standards volume information, refer to the standard’s
Originally published as ASTM E 1707–95. Last previous ASTM edition Document Summary page on the ASTM website.
ε1 ε1 3
E 1707–95 .ASTME 1707–95 wasadoptedbyISOin1998withtheintermediate Available from Association for the Advancement of Medical Instrumentation,
designation ISO 15572:1998(E). The present International Standard ISO/ASTM 1110 North Glebe Road, Suite 220, Arlington, VA 22201-4795, U.S.A.
4
51707:2015(E) is a major revision of the last previous edition ISO/ASTM Available from International Organization for Standardization (ISO), 1, ch. de
51707:2005(E), which replaced ISO/ASTM 51707:2002(E). la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
© ISO/ASTM International 2015 – All rights reserved
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ISO/ASTM 51707:2015(E)
2.4 Joint Committee for Guides in Metrology (JCGM) 3.2.4 coeffıcient of variation (CV)—sample standard devia-
Reports:
tion expressed as a percentage of sample average value (see
JCGM 100:2008, GUM 1995, with minor correc- 3.2.2 and 3.2.19):
tions, Evaluation of measurement data – Guide to the
S
5
CV 5 3100 % (2)
Expression of Uncertainty in Measurement
x¯
JCGM 200:2008, VIM, International vocabulary of metrol-
6
3.2.5 combined standard measurement uncertainty [VIM,
ogy – Basis and general concepts and associated terms
2.31]—standard measurement uncertainty that is obtained us-
7
2.5 ICRU Reports:
ing the individual standard measurement uncertainties associ-
ICRU Report 80 Dosimetry Systems for Use in Radiation
ated with the input quantities in a measurement model.
Processing
3.2.5.1 Discussion—
ICRU Report 85a Fundamental Quantities and Units for
(1) Itisalsoreferredtoas‘combinedstandarduncertainty’.
Ionizing Radiation
(2) In case of correlations of input quantities in a measure-
ment model, covariances must also be taken into account when
3. Terminology
calculating the combined standard measurement uncertainty.
3.1 Definitions:
3.2.6 coverage factor (k) [VIM, 2.38]—number larger than
NOTE 1—For definitions quoted here from VIM, only the text of the
one by which a combined standard measurement uncertainty is
definition is kept here. Any NOTES or EXAMPLES are not included.
multiplied to obtain an expanded measurement uncertainty.
They can be reviewed by referring to VIM (JCGM 200:2008).
3.2.6.1 Discussion—Acoverage factor, k, is typically in the
3.2 Definitions:
range of 2 to 3 (see 5.2.4).
3.2.1 approved laboratory—laboratory that is a recognized
3.2.7 expanded uncertainty [GUM, 2.3.5]—quantity defin-
national metrology institute; or has been formally accredited to
ing the interval about the result of a measurement that may be
ISO/IEC 17025; or has a quality system consistent with the
expected to encompass a large fraction of the distribution of
requirements of ISO/IEC 17025.
values that could reasonably be attributed to the measurand.
3.2.1.1 Discussion—A recognized national metrology insti-
tute or other calibration laboratory accredited to ISO/IEC
3.2.7.1 Discussion—Expanded uncertainty is obtained by
17025 should be used for irradiation of dosimeters or dose multiplying the combined standard uncertainty by a coverage
measurements for calibration in order to ensure traceability to
factor, the value of which determines the magnitude of the
a national or international standard. A calibration certificate
‘fraction’. Expanded uncertainty is also referred to as ‘overall
provided by a laboratory not having formal recognition or
uncertainty’.
accreditation will not necessarily be proof of traceability to a
3.2.8 influence quantity [VIM, 2.52]—quantity that, in a
national or international standard.
direct measurement, does not affect the quantity that is actually
3.2.2 arithmetic mean, average [GUM, C.2.19]—sum of
measured, but affects the relation between the indication and
values divided by the number of values:
the measurement result.
1
3.2.8.1 Discussion—In radiation processing dosimetry, this
x¯ 5 x , i 51, 2, 3 … n (1)
( i
n
i
term includes temperature, relative humidity, time intervals,
light, radiation energy, absorbed dose rate, and other factors
where:
that might affect dosimeter response, as well as quantities
x = individual values of parameters with i=1,2,3. n.
i
associated with the measurement instrument.
3.2.2.1 Discussion—The term ‘mean’ is used generally
3.2.9 level of confidence—probability that the value of a
when referring to a population parameter and the term ‘aver-
parameter will fall within the given range.
age’ when referring to the result of a calculation on the data
3.2.10 measurand[VIM,2.3]—quantityintendedtobemea-
obtained in a sample.
sured.
3.2.3 calibration curve [VIM, 4.31]—expression of the
3.2.10.1 Discussion—In radiation processing dosimetry, the
relation between indication and corresponding measured quan-
measurand is the absorbed dose (Gy) or simply ‘dose’.
tity value.
3.2.3.1 Discussion—In radiation processing standards, the 3.2.11 measurement [VIM, 2.1]—process of experimentally
term “dosimeter response” is generally used for “indication”. obtaining one or more quantity values that can reasonably be
attributed to a quantity.
3.2.12 measurement uncertainty[VIM,2.26]—non-negative
5
Document produced by Working Group 1 of the Joint Committee for Guides in
parameter characterizing the dispersion of the quantity values
Metrology (JCGM/WG 1). Available free of charge at the BIPM website (http://
beingattributedtoameasurand,basedontheinformationused.
www.bipm.org).
6
Document produced by Working Group 2 of the Joint Committee for Guides in 3.2.12.1 Discussion—
Metrology (JCGM/WG 2). Available free of charge at the BIPM website (http://
(1) Measurement uncertainty includes components arising
www.bipm.org).
7 from systematic effects, such as components associated with
Available from International Commission on Radiation Units and
Measurements, 7910 Woodmont Ave., Suite 800 Bethesda, MD 20814, U.S.A. corrections and the assigned quantity values of measurement
© ISO/ASTM International 2015 – All rights reserved
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ISO/ASTM 51707:2015(E)
standards, as well as the definitional uncertainty. Sometimes (2) Repeatability conditions include: the same measure-
estimated systematic effects are not corrected for but, instead,
ment procedure, the same observer, the same measuring
associated measurement uncertainty components are incorpo-
instrument used under the same conditions, the same location,
rated.
repetition over a short period of time.
(2) The parameter may be, for example, a standard devia-
(3) Repeatability may be expressed quantitatively in terms
tion called standard measurement uncertainty (or a specified
of the dispersion characteristics of the results.
multiple of it), or the half-width of an interval, having a stated
3.2.18 reproducibility (of results of measurements) [GUM,
coverage probability.
B.2.16]—closeness of the agreement between the results of
(3) Measurement uncertainty comprises, in general, many
measurements of the same measurand carried out under
components. Some of these may be evaluated by Type A
changed conditions of measurement.
evaluation of measurement uncertainty from the statistical
3.2.18.1 Discussion—
distribution of the quantity values from series of measurements
(1) A valid statement of reproducibility requires specifica-
and can be characterized by standard deviations. The other
components, which may be evaluated by Type B evaluation of tion of the conditions changed.
measurement uncertainty, can also be characterized by stan- (2) The changed conditions may include: principle of
dard deviations, evaluated from probability density functions
measurements, method of measurement, observer, measuring
based on experience or other information.
instrument, reference standard, location, conditions of use and
(4) In general, for a given set of information, it is under-
time.
stood that the measurement uncertainty is associated with a
(3) Reproducibility may be expressed quantitatively in
stated quantity value attributed to the measurand. A modifica-
terms of the dispersion characteristics of the results.
tion of this value results in a modification of the associated
3.2.19 sample standard deviation (S) [adapted from GUM,
uncertainty.
C.2.21]—measure of dispersion of values of the same mea-
3.2.13 metrological traceability [VIM, 2.41]—property of a
surand expressed as the positive square root of the sample
measurement result whereby the result can be related to a
variance.
reference through a documented unbroken chain of
3.2.20 sample variance [GUM, C.2.20]—measure of
calibrations, each contributing to the measurement uncertainty.
dispersion, which is the sum of the squared deviations of
3.2.13.1 Discussion—
observations from their average divided by (n –1), given by the
(1) The unbroken chain of calibrations is referred to as
expression:
“traceability chain”.
(2) Metrological traceability of a measurement result does 2
~x 2 x¯!
( i
2
S 5 (3)
not ensure that the measurement uncertainty is adequate for a
n 2 1
~ !
given purpose or that there is an absence of mistakes.
where:
(3) The abbreviated term “traceability” is sometimes used
to mean ‘metrological traceability’ as well as other concepts, x = individual value of parameter with i = 1, 2 . n, and
i
x¯ = mean of n values of parameter (see 3.2.2).
such as ‘sample traceability’, ‘document traceability’, ‘instru-
ment traceability’ or ‘material traceability’, where the history
3.2.21 standard measurement uncertainty [VIM, 2.30]—
(“trace”) of an item is meant. Therefore, the full term of
measurement uncertainty expressed as a standard deviation.
“metrological traceability” is preferred if there is any risk of
3.2.21.1 Discussion—Also referred to as ‘standard uncer-
confusion.
tainty of measurement’ or ‘standard uncertainty’.
3.2.14 quadrature—method used in estimating combined
3.2.22 true value [VIM, 2.11]—quantity value consistent
standard uncertainty from independent sources by taking the
with the definition of a quantity.
positive square root of the sum of the squares of individual
3.2.22.1 Discussion—True value is by its nature indetermi-
components of uncertainty, for example, coefficient of varia-
nateandonlyanidealizedconcept.Inthisguidetheterms“true
tion.
value of a measurand” and “value of a measurand” are viewed
3.2.15 quantity [VIM, 1.1]—property of a phenomenon,
as equivalent (see 5.1.1).
body, or substance, where the property has a magnitude that
can be expressed as a number and a reference. 3.2.23 TypeAevaluation of measurement uncertainty[VIM,
2.28]—evaluation of a component of measurement uncertainty
3.2.16 quantity value [VIM, 1.19]—number and reference
by a statistical analysis of measured quantity values obtained
together expressing magnitude of a quantity.
under defined measurement conditions.
3.2.16.1 Discussion—For example, absorbed dose of 25
3.2.24 Type B evaluation of measurement uncertainty[VIM,
kGy.
2.29]—evaluation of a component of measurement uncertainty
3.2.17 repeatability (of results of measurements) [GUM,
determined by means other than a Type A evaluation of
B.2.15]—closeness of the agreement between the results of
measurement uncertainty.
successive measurements of the same measurand carried out
under the same conditions of measurement. 3.2.25 uncertainty budget[VIM,2.33]—statementofamea-
3.2.17.1 Discussion— surement uncertainty, of the components of that measurement
(1) These conditions are called ‘repeatability conditions’. uncertainty, and of their calculation and combination.
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ISO/ASTM 51707:2015(E)
3.2.25.1 Discussion—An uncertainty budget should include measurand, the method of measurement, the measurement
the measurement model, estimates, and measurement uncer- system and the measurement procedure.
tainties associated with the quantities in the measurement 5.1.2 In general, the result of a measurement is the approxi-
model, covariances, type of applied probability density mation or best estimate of the true value of the measurand
functions, degrees of freedom, type of evaluation of measure- (dose) and thus is complete only when accompanied by a
ment uncertainty, and any coverage factor. statement of the uncertainty of that estimate.
3.3 Definitions of other terms used in this standard that 5.2 Uncertainty:
pertain to quality and statistics may be found in ASTM 5.2.1 The uncertainty of the measurement result reflects the
Terminology E456. Definitions of other terms used in this inability to know the true value of the measurand. A lower
standard that pertain to radiation measurement and dosimetry value of overall uncertainty reflects a higher degree of confi-
may be found in ASTM Terminology E170. Definitions in dence in the estimate of the value of the measurand.
ASTM Terminology E170 are compatible with ICRU 85a; that
NOTE 2—The result of any individual measurement can unknowingly
document, therefore, may be used as an alternative reference.
be very close to the value of the measurand even though it may have a
large uncertainty.Thus the uncertainty of a measurement result should not
be confused as the unknown error.
4. Significance and use
5.2.2 The uncertainty associated with a measurement can
4.1 All measurements, including dose measurements, have
arise from a number of different components, examples of
an associated uncertainty. The magnitude of the measurement
some of which are listed in Section 7. In assessing measure-
uncertainty is important for assessing the quality of the results
mentuncertainty,itisnecessarytoconsiderallstepsassociated
of the measurement system.
with making a measurement and assign to each step a value for
4.2 Information on the range of achievable uncertainty
the uncertainty introduced. These individual components can
values for specific dosimetry systems is given in the ISO/
then be collected together to produce a combined uncertainty
ASTM standards for the specific dosimetry systems. While the
for the measurement. The results of this type of analysis are
uncertainty values given in specific dosimetry standards are
often presented in the form of a table, referred to as an
achievable, it should be noted that both smaller and larger
uncertaintybudget(seeAnnexA2).Componentsofuncertainty
uncertainty values might be obtained depending on measure-
are generally classified as TypeAor Type B, depending on the
mentconditionsandinstrumentation.Formoreinformationsee
method used to evaluate them.
also ISO/ASTM 52628.
5.2.2.1 The purpose of the TypeAand Type B classification
4.3 This guide uses the methodology adopted by the GUM
is to indicate the two different ways of evaluating uncertainty
for estimating uncertainties in measurements (see 2.4).
components. Both types of evaluation are based on probability
Therefore, components of uncertainty are evaluated as either
distributions and the uncertainty components resulting from
Type A uncertainty or Type B uncertainty.
each type are quantified by a standard deviation or a variance.
5.2.2.2 Thus,aTypeAstandarduncertaintyisobtainedfrom
4.4 Quantifying individual components of uncertainty may
a probability density function derived from a series of repeated
assist the user in identifying actions to reduce the measurement
observations (see 8.1), while a Type B standard uncertainty is
uncertainty.
obtained from an assumed probability density function based
4.5 Periodically, the uncertainty should be reassessed to
on the degree of belief that an event will occur (see 8.2). Both
confirm the existing estimate. Should changes occur that could
approaches are valid interpretations of probability.
influence the existing component estimates or result in the
5.2.3 The combined standard uncertainty, denoted by u,of
c
addition of new components of uncertainty, a new estimate of
the result of a measurement is obtained by combining all the
uncertainty should be established.
components of uncertainty of both categories (see 9.1.1).
4.6 Although this guide provides a framework for assessing 5.2.4 Typically, an expanded uncertainty U is calculated to
uncertainty, it cannot substitute for critical thinking, intellec-
provide an interval about the result of a measurement within
tual honesty, and professional skill. The evaluation of uncer- which the true value is expected to lie. The value of U is
tainty is neither a routine task nor a purely mathematical one;
obtained by multiplying the combined standard uncertainty u
c
it depends on detailed knowledge of the nature of the mea- by a coverage factor k (see 9.2).
surand and of the measurement method and procedure used.
NOTE 3—The coverage factor k is always to be stated when reporting
The quality and utility of the uncertainty quoted for the result
expanded uncertainty, so that the combined standard uncertainty of the
of a measurement therefore ultimately depends on the
measured quantity can be recovered.
understanding, critical analysis, and integrity of those who
6. Evaluation of Type A and Type B standard
contribute to the assignment of its value (JCGM 100:2008).
uncertainty
5. Basic concepts—components of uncertainty 6.1 Measurement Procedure:
6.1.1 The measurand Y (absorbed dose) is generally not
5.1 Measurement:
measurable directly, but depends on N other quantities X , X ,
1 2
5.1.1 The objective of a measurement is to determine the
..., X through a functional relationship: Y5f~X , X , …, X !.
N 1 2 N
value of the measurand (for example, dose), that is, the value
of the specific quantity to be measured (dose).Ameasurement 6.1.1.1 The input quantities X , X , . X and their associ-
1 2 N
therefore begins with an appropriate specification of the ated uncertainties may be determined directly in the current
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ISO/ASTM 51707:2015(E)
humidity have significant effects on measured absorbance. Controlling
measurement process by means of repeated observations (such
these influence quantities during calibration and routine dosimetry will
as Type A); these input quantities may include influence
reduce the uncertainty in dose estimates.
quantities such as temperature or humidity. They may also
involve input quantities related to activities such as calibration 6.3 Type B Evaluation of Standard Uncertainty:
of routine dosimetry systems under conditions that differ from
6.3.1 The Type B component of uncertainty is evaluated by
those during use (different dose rates, temperature cycle, etc.).
using all relevant information on the possible variability of the
Other quantities that may be involved are those due to use of
input quantities X. For the input value X that has not been
i i
reference or transfer standard dosimeters.
obtained from repeated measurements, the estimated variance,
2
6.1.1.2 The input quantities X , X , X . X and associated u ,orstandarduncertainty, u ,isevaluatedbyjudgmentusing
1 2 3 N B B
uncertainties may be treated either individually, for example, all relevant information on the possible variability of X. This
i
X or X or as aggregates, for example, (X . X ) where p < N. pool of information may include previous measurement data or
1 2 1 p
documented performance characteristics of the dosimetry sys-
6.1.1.3 Grouping of input quantities is determined by the
characteristics of the selected dosimetry system, method of tem. The uncertainty estimated in this way is referred to as a
Type B standard uncertainty, u .
calibration, measurement application environme
...