SIST EN ISO 20785-1:2017
(Main)Dosimetry for exposures to cosmic radiation in civilian aircraft - Part 1: Conceptual basis for measurements (ISO 20785-1:2012)
Dosimetry for exposures to cosmic radiation in civilian aircraft - Part 1: Conceptual basis for measurements (ISO 20785-1:2012)
ISO 20785:2012 gives the conceptual basis for the determination of ambient dose equivalent for the evaluation of exposure to cosmic radiation in civilian aircraft and for the calibration of instruments used for this purpose.
Dosimetrie für die Belastung durch kosmische Strahlung in Zivilluftfahrzeugen - Teil 1: Konzeptionelle Grundlage für Messungen (ISO 20785-1:2012)
Dosimétrie pour l'exposition au rayonnement cosmique à bord d'un avion civil - Partie 1: Fondement théorique des mesurages (ISO 20785-1:2012)
L'ISO 20785-1:2012 donne les principes de base permettant de déterminer l'équivalent de dose ambiant pour l'évaluation de l'exposition au rayonnement cosmique à bord d'un avion civil, ainsi que pour l'étalonnage des instruments utilisés à cette fin.
Dozimetrija za merjenje izpostavljenosti kozmičnemu sevanju v civilnem letalskem prometu - 1. del: Konceptualna osnova za meritve (ISO 20785-1:2012)
Standard ISO 20785:2012 podaja konceptualno osnovo za določanje okoljskega ekvivalentnega odmerka za ocenjevanje izpostavljenosti kozmičnemu sevanju v civilnem letalskem prometu in za umerjanje instrumentov, ki se uporabljajo za ta namen.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 20785-1:2017
01-december-2017
'R]LPHWULMD]DPHUMHQMHL]SRVWDYOMHQRVWLNR]PLþQHPXVHYDQMXYFLYLOQHPOHWDOVNHP
SURPHWXGHO .RQFHSWXDOQDRVQRYD]DPHULWYH ,62
Dosimetry for exposures to cosmic radiation in civilian aircraft - Part 1: Conceptual basis
for measurements (ISO 20785-1:2012)
Dosimétrie pour l'exposition au rayonnement cosmique à bord d'un avion civil - Partie 1:
Fondement théorique des mesurages (ISO 20785-1:2012)
Ta slovenski standard je istoveten z: EN ISO 20785-1:2017
ICS:
17.240 Merjenje sevanja Radiation measurements
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
SIST EN ISO 20785-1:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 20785-1:2017
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SIST EN ISO 20785-1:2017
EN ISO 20785-1
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2017
EUROPÄISCHE NORM
ICS 13.280; 49.020
English Version
Dosimetry for exposures to cosmic radiation in civilian
aircraft - Part 1: Conceptual basis for measurements (ISO
20785-1:2012)
Dosimétrie pour l'exposition au rayonnement
cosmique à bord d'un avion civil - Partie 1: Fondement
théorique des mesurages (ISO 20785-1:2012)
This European Standard was approved by CEN on 13 September 2017.
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, 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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20785-1:2017 E
worldwide for CEN national Members.
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SIST EN ISO 20785-1:2017
EN ISO 20785-1:2017 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 20785-1:2017
EN ISO 20785-1:2017 (E)
European foreword
The text of ISO 20785-1:2012 has been prepared by Technical Committee ISO/TC 85 “Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 20785-1:2017 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2018, and conflicting national standards shall be
withdrawn at the latest by April 2018.
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.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 20785-1:2012 has been approved by CEN as EN ISO 20785-1:2017 without any
modification.
3
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SIST EN ISO 20785-1:2017
INTERNATIONAL ISO
STANDARD 20785-1
Second edition
2012-12-15
Dosimetry for exposures to cosmic
radiation in civilian aircraft —
Part 1:
Conceptual basis for measurements
Dosimétrie pour l’exposition au rayonnement cosmique à bord d’un
avion civil —
Partie 1: Fondement théorique des mesurages
Reference number
ISO 20785-1:2012(E)
©
ISO 2012
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SIST EN ISO 20785-1:2017
ISO 20785-1:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the
address below or ISO’s member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 20785-1:2017
ISO 20785-1:2012(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
2.1 General . 1
2.2 Quantities and units . 2
2.3 Atmospheric radiation field . 8
3 General considerations .10
3.1 General description of the cosmic radiation field in the atmosphere .10
3.2 General calibration considerations for the dosimetry of cosmic radiation fields
in aircraft .11
3.3 Conversion coefficients .13
4 Dosimetric devices .13
4.1 Introduction .13
4.2 Active devices .14
4.3 Passive devices .17
Annex A (informative) Representative particle fluence rate energy distributions for the cosmic
radiation field at flight altitudes for solar minimum and maximum conditions and for
[80]
minimum and maximum vertical cut-off rigidity .20
Bibliography .24
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SIST EN ISO 20785-1:2017
ISO 20785-1:2012(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20785-1 was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 2, Radiological protection.
This second edition cancels and replaces the first edition (ISO 20785-1:2006), which has been
technically revised.
ISO 20785 consists of the following parts, under the general title Dosimetry for exposures to cosmic
radiation in civilian aircraft:
— Part 1: Conceptual basis for measurements
— Part 2: Characterization of instrument response
Measurements at aviation altitudes is to form the subject of a future Part 3.
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ISO 20785-1:2012(E)
Introduction
Aircraft crews are exposed to elevated levels of cosmic radiation of galactic and solar origin and
secondary radiation produced in the atmosphere, the aircraft structure and its contents. Following
[1]
recommendations of the International Commission on Radiological Protection in Publication 60,
[2]
confirmed by Publication 103, the European Union (EU) introduced a revised Basic Safety Standards
[3]
Directive which included exposure to natural sources of ionizing radiation, including cosmic radiation,
as occupational exposure. The Directive requires account to be taken of the exposure of aircraft crews
liable to receive more than 1 mSv per year. It then identifies the following four protection measures:
(i) to assess the exposure of the crew concerned; (ii) to take into account the assessed exposure when
organizing working schedules with a view to reducing the doses of highly exposed crews; (iii) to inform
the workers concerned of the health risks their work involves; and (iv) to apply the same special protection
during pregnancy to female crews in respect of the “child to be born” as to other female workers. The EU
Council Directive has already been incorporated into laws and regulations of EU Member States and is
being included in the aviation safety standards and procedures of the Joint Aviation Authorities and the
European Air Safety Agency. Other countries such as Canada and Japan have issued advisories to their
airline industries to manage aircraft crew exposure.
For regulatory and legislative purposes, the radiation protection quantities of interest are the
equivalent dose (to the foetus) and the effective dose. The cosmic radiation exposure of the body is
essentially uniform and the maternal abdomen provides no effective shielding to the foetus. As a result,
the magnitude of equivalent dose to the foetus can be put equal to that of the effective dose received
by the mother. Doses on board aircraft are generally predictable, and events comparable to unplanned
exposure in other radiological workplaces cannot normally occur (with the rare exceptions of extremely
intense and energetic solar particle events). Personal dosemeters for routine use are not considered
necessary. The preferred approach for the assessment of doses of aircraft crews, where necessary, is
to calculate directly the effective dose per unit time, as a function of geographic location, altitude and
solar cycle phase, and to fold these values with flight and staff roster information to obtain estimates of
effective doses for individuals. This approach is supported by guidance from the European Commission
[4]
and the ICRP in Publication 75.
The role of calculations in this procedure is unique in routine radiation protection and it is widely
accepted that the calculated doses should be validated by measurement. The effective dose is not
directly measurable. The operational quantity of interest is ambient dose equivalent, H*(10). In order
to validate the assessed doses obtained in terms of effective dose, calculations can be made of ambient
dose equivalent rates or route doses in terms of ambient dose equivalent, and values of this quantity
determined by measurements traceable to national standards. The validation of calculations of ambient
dose equivalent for a particular calculation method may be taken as a validation of the calculation of
the effective dose by the same computer code, but this step in the process may need to be confirmed.
The alternative is to establish a priori that the operational quantity ambient dose equivalent is a good
estimator of effective dose and equivalent dose to the foetus for the radiation fields being considered,
in the same way that the use of the operational quantity personal dose equivalent is justified for
the estimation of effective dose for radiation workers. Ambient dose equivalent rate as a function of
geographic location, altitude and solar cycle phase is then calculated and folded with flight and staff
roster information.
The radiation field in aircraft at altitude is complex, with many types of ionizing radiation present, with
energies ranging up to many GeV. The determination of ambient dose equivalent for such a complex
radiation field is difficult. In many cases, the methods used for the determination of ambient dose
equivalent in aircraft are similar to those used at high-energy accelerators in research laboratories.
Therefore, it is possible to recommend dosimetric methods and methods for the calibration of dosimetric
devices, as well as the techniques for maintaining the traceability of dosimetric measurements to
national standards. Dosimetric measurements made to evaluate ambient dose equivalent must be
performed using accurate and reliable methods that ensure the quality of readings provided to workers
and regulatory authorities. This part of ISO 20785 gives a conceptual basis for the characterization of
the response of instruments for the determination of ambient dose equivalent in aircraft.
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SIST EN ISO 20785-1:2017
ISO 20785-1:2012(E)
Requirements for the determination and recording of the cosmic radiation exposure of aircraft crews have
been introduced into the national legislation of EU Member States and other countries. Harmonization
of methods used for determining ambient dose equivalent and for calibrating instruments is desirable
to ensure the compatibility of measurements performed with such instruments.
This part of ISO 20785 is intended for the use of primary and secondary calibration laboratories for
ionizing radiation, by radiation protection personnel employed by governmental agencies, and by
industrial corporations concerned with the determination of ambient dose equivalent for aircraft crews.
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SIST EN ISO 20785-1:2017
INTERNATIONAL STANDARD ISO 20785-1:2012(E)
Dosimetry for exposures to cosmic radiation in civilian
aircraft —
Part 1:
Conceptual basis for measurements
1 Scope
This part of ISO 20785 gives the conceptual basis for the determination of ambient dose equivalent for
the evaluation of exposure to cosmic radiation in civilian aircraft and for the calibration of instruments
used for that purpose.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 General
2.1.1
calibration
operation that, under specified conditions, establishes a relation between the conventional quantity, H ,
0
and the indication, G
Note 1 to entry: A calibration may be expressed by a statement, calibration function, calibration diagram,
calibration curve, or calibration table. In some cases, it may consist of an additive or multiplicative correction of
the indication with associated measurement uncertainty.
Note 2 to entry: Calibration should not be confused with adjustment of a measuring system, often mistakenly
called “self-calibration”, or with verification of calibration.
Note 3 to entry: Often, the first step alone in the above definition is perceived as being calibration.
2.1.2
calibration coefficient
N
coeff
quotient of the conventional quantity value to be measured and the corrected indication of the instrument
Note 1 to entry: The calibration coefficient is equivalent to the calibration factor multiplied by the instrument constant.
Note 2 to entry: The reciprocal of the calibration coefficient, N , is the response.
coeff
Note 3 to entry: For the calibration of some instruments, e.g. ionization chambers, the instrument constant and
the calibration factor are not identified separately but are applied together as the calibration coefficient.
Note 4 to entry: It is necessary, in order to avoid confusion, to state the quantity to be measured, for example:
the calibration coefficient with respect to fluence, N , the calibration coefficient with respect to kerma, N , the
Φ K
calibration coefficient with respect to absorbed dose, N .
D
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ISO 20785-1:2012(E)
2.1.3
indication
G
quantity value provided by a measuring instrument or a measuring system
Note 1 to entry: An indication can be presented in visual or acoustic form or can be transferred to another device.
An indication is often given by the position of a pointer on the display for analogue outputs, a displayed or printed
number for digital outputs, a code pattern for code outputs, or an assigned quantity value for material measures.
Note 2 to entry: An indication and a corresponding value of the quantity being measured are not necessarily
values of quantities of the same kind.
2.1.4
reference conditions
conditions of use prescribed for testing the performance of a detector assembly or for comparison of
results of measurements
Note 1 to entry: The reference conditions represent the values of the set of influence quantities for which the
calibration result is valid without any correction.
Note 2 to entry: The value of the measurand may be chosen freely in agreement with the properties of the
detector assembly to be calibrated. The quantity to be measured is not an influence quantity but may influence
the calibration result and the response.
2.1.5
response
R
quotient of the indication, G, or the corrected indication, G , and the conventional quantity value
corr
to be measured
Note 1 to entry: To avoid confusion, it is necessary to specify which of the quotients, given in the definition of the
response (to G or to G ) is applied. Furthermore, it is necessary, in order to avoid confusion, to state the quantity
corr
to be measured, for example: the response with respect to fluence, R , the response with respect to kerma, R , the
Φ K
response with respect to absorbed dose, R .
D
Note 2 to entry: The reciprocal of the response under the specified conditions is equal to the calibration
coefficient N
coeff.
Note 3 to entry: The value of the response may vary with the magnitude of the quantity to be measured. In such
cases the detector assembly’s response is said to be non-constant.
Note 4 to entry: The response usually varies with the energy and direction distribution of the incident radiation.
It is, therefore, useful to consider the response as a function, R(E,Ω), of the radiation energy, E, and of the direction,
Ω , of the incident monodirectional radiation. R(E) describes the “energy dependence” and R(Ω) the “angle
dependence” of response; for the latter, Ω may be expressed by the angle, α, between the reference direction of
the detector assembly and the direction of an external monodirectional field.
2.2 Quantities and units
2.2.1
particle fluence
fluence
Φ
number, dN, at a given point of space, of particles incident on a small spherical domain, divided by the
cross-sectional area, da, of that domain:
dN
Φ =
da
−2 −2
Note 1 to entry: The unit of the fluence is m ; a frequently used unit is cm .
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ISO 20785-1:2012(E)
Note 2 to entry: The energy distribution of the particle fluence, Φ , is the quotient, dΦ, by dE, where dΦ is the
E
fluence of particles of energy between E and E+dE. There is an analogous definition for the direction distribution,
Φ , of the particle fluence. The complete representation of the double differential particle fluence can be written
Ω
(with arguments) Φ (E,Ω), where the subscripts characterize the variables (quantities) for differentiation and
E,Ω
where the symbols in the brackets describe the values of the variables. The values in the brackets are needed for
special function values, e.g. the energy distribution of the particle fluence at energy E = E is written as Φ (E ). If
0 E 0
no special values are indicated, the brackets may be omitted.
2.2.2
particle fluence rate
fluence rate
Φ
rate of the particle fluence expressed as
2
dΦ d N
Φ ==
dt ddat⋅
where dΦ is the increment of the particle fluence during an infinitesimal time interval with duration dt
−2 −1 −2 −1
Note 1 to entry: The unit of the fluence rate is m s , a frequently used unit is cm s .
2.2.3
energy imparted
ε
for ionizing radiation in the matter within a given three-dimensional domain,
εε=
∑ i
where
ε is the energy deposited in a single interaction, i, and given by ε = ε – ε + Q, where
i i in out
ε is the energy of the incident ionizing particle, excluding rest energy,
in
ε is the sum of the energies of all ionizing particles leaving the interaction, excluding rest
out
energy, and
Q is the change in the rest energies of the nucleus and of all particles involved in the interaction
Note 1 to entry: Energy imparted is a stochastic quantity.
Note 2 to entry: The unit of the energy imparted is J.
2.2.4
mean energy imparted
ε
mean energy imparted to the matter in a given domain, expressed as
ε =−RR + Q
in out ∑
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SIST EN ISO 20785-1:2017
ISO 20785-1:2012(E)
where
R is the radiant energy of all those charged and uncharged ionizing particles that enter the
in
domain,
R is the radiant energy of all those charged and uncharged ionizing particles that leave the
out
domain, and
∑Q is the sum of all changes of the rest energy of nuclei and elementary particles that occur in
that domain
Note 1 to entry: This quantity has the meaning of expected value of the energy imparted.
Note 2 to entry: The unit of the mean energy imparted is J.
2.2.5
specific energy imparted
specific energy
z
for any ionizing radiation,
ε
z =
m
where
ε is the energy imparted to the irradiated matter,
m is the mass of the irradiated matter
Note 1 to entry: Specific energy imparted is a stochastic quantity.
Note 2 to entry: In the limit of a small domain, the mean specific energy imparted is equal to the absorbed dose.
Note 3 to entry: The specific energy imparted can be the result of one or more (energy-deposition) events.
–1
Note 4 to entry: The unit of specific energy is J⋅kg , with the special name gray (Gy).
2.2.6
absorbed dose
D
for any ionizing radiation,
dε
D=
dm
where
is the mean energy imparted by ionizing radiation to an element of irradiated matter of mass
dε
dm, where
ε = Dmd
∫
Note 1 to entry: In the limit of a small domain, the mean specific energy is equal to the absorbed dose.
−1
Note 2 to entry: The unit of absorbed dose is J kg , with the special name gray (Gy).
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ISO 20785-1:2012(E)
2.2.7
kerma
K
for indirectly ionizing (uncharged) particles, the mean sum of the initial kinetic energies dE of all the
tr
charged ionizing particles liberated by uncharged ionizing particles in an element of matter, divided by
the mass dm of that element:
dE
tr
K =
dm
Note 1 to entry: Quantity dE includes the kinetic energy of the charged particles emitted in the decay of excited
tr
atoms or molecules or nuclei.
−1
Note 2 to entry: The unit of kerma is J kg , with the special name gray (Gy).
2.2.8
unrestricted linear energy transfer
linear energy transfer
LET
L
Δ
for an ionizing charged particle, the mean energy, dE , imparted locally to matter along a small path
Δ
through the matter minus the sum of the kinetic energies of all the electrons released with kinetic
energies in excess of Δ, divided by the length, dl:
dE
Δ
L =
Δ
dl
Note 1 to entry: This quantity is not completely defined unless Δ is specified, i.e. the maximum kinetic energy of
secondary electrons whose energy is considered to be “locally deposited”. Δ may be expressed in eV.
Note 2 to entry: Linear energy transfer is often abbreviated LET, but to which should be appended the subscript
Δ or its numerical value.
−1 −1
Note 3 to entry: The unit of the linear energy transfer is J m , a frequently used unit is keV μm .
Note 4 to entry: If no energy cut-off is imposed, the unrestricted linear energy transfer L is equal to the linear
∞
electronic stopping power S and may be denoted simply as L.
el
2.2.9
dose equivalent
H
at the point of interest in tissue,
HD= Q
where
D is the absorbed dose,
Q is the quality factor at that point, and
∞
HQ= ()LD dL
L
∫
L−0
Note 1 to entry: Q is determined by the unrestricted linear energy transfer, L (often denoted as L or LET), of
∞
charged particles passing through a small volume element (domains) at this point (the value of L is given for
∞
charged particles in water, not in tissue; the difference, however, is small). The dose equivalent at a point in tissue
is then given by the above formula, where D = dD/dL is the distribution in terms of L of the absorbed dose at the
L
point of interest.
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ISO 20785-1:2012(E)
[2]
Note 2 to entry: The relationship of Q and L is given in ICRP Publication 103 (ICRP, 2007).
−1
Note 3 to entry: The unit of dose equivalent is J kg , with the special name sievert (Sv).
2.2.10
single-event dose-mean specific energy
dose-mean specific energy per event
z
D
expectation
∞
zz= dz()dz
D 1
∫
0
where d (z)is the dose probability density of z
1
Note 1 to entry: The dose probability density of z is given by d (z), where d (z) dz is the fraction of the absorbed
1 1
dose delivered in single events with specific energies in the interval from z to z+dz.
2.2.11
lineal energy
y
quotient of the energy, ε , imparted to the matter in a given volume by a single energy deposition event,
s
by the mean chord length, l , in that volume:
ε
s
y=
l
−1 −1
Note 1 to entry: The unit of lineal energy is J m , a frequently used unit is keV μm .
2.2.12
dose-mean lineal energy
...
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