Radiological protection - X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy - Part 4: Calibration of area and personal dosemeters in low energy X reference radiation fields (ISO 4037-4:2019)

This document gives guidelines on additional aspects of the characterization of low energy photon radiations and on the procedures for calibration and determination of the response of area and personal dose(rate)meters as a function of photon energy and angle of incidence. This document concentrates on the accurate determination of conversion coefficients from air kerma to Hp(10), H*(10), Hp(3) and H'(3) and for the spectra of low energy photon radiations. As an alternative to the use of conversion coefficients the direct calibration in terms of these quantities by means of appropriate reference instruments is described.

Strahlenschutz - Röntgen- und Gamma-Referenzstrahlungsfelder zur Kalibrierung von Dosimetern und Dosisleistungsmessgeräten und zur Bestimmung ihres Ansprechvermögens als Funktion der Photonenenergie - Teil 4: Kalibrierung von Orts- und Personendosimetern in niedrigenergetischen Röntgen-Referenzstrahlungsfeldern (ISO 4037-4:2019)

Dieses Dokument gibt Leitlinien für zusätzliche Aspekte der Charakterisierung der niederenergetischen Pho-tonenstrahlungsfelder und für die Verfahren für die Kalibrierung und Bestimmung des Ansprechvermögens von Orts- und Personendosimetern und Dosisleistungsmessgeräten als Funktion von Photonenenergie und Strahleneinfallswinkel. Dieses Dokument konzentriert sich auf die genaue Bestimmung der Konversionskoef-fizienten von Luftkerma auf Hp(10), H*(10), Hp(3) und H'(3) und auf die Spektren von niederenergetischen Photonenstrahlungsfeldern. Als Alternative zur Verwendung von Konversionskoeffizienten wird die direkte Kalibrierung in Bezug auf diese Messgrößen mit Hilfe geeigneter Referenzmessgeräte beschrieben.

Radioprotection - Rayonnements X et gamma de référence pour l'étalonnage des dosimètres et des débitmètres et pour la détermination de leur réponse en fonction de l'énergie des photons - Partie 4: Étalonnage des dosimètres de zone et individuels dans des champs de référence X de faible énergie (ISO 4037-4:2019)

Le présent document donne des indications concernant les aspects complémentaires de la caractérisation des rayonnements de photons de faible énergie et les procédures pour l'étalonnage et la détermination de la réponse des dosimètres ou débitmètres de zone et individuels en fonction de l'énergie des photons et de l'angle d'incidence. Le présent document traite de la détermination précise des coefficients de conversion du kerma dans l'air en équivalents de dose Hp(10), H*(10), Hp(3) et H'(3) et pour les spectres de rayonnement de photons de faible énergie. Une méthode d'étalonnage direct de ces grandeurs au moyen d'instruments de référence appropriés est donnée comme alternative à l'utilisation des coefficients de conversion.

Radiološka zaščita - Referenčno sevanje z rentgenskimi in gama žarki za kalibracijo dozimetrov in merilnikov doze sevanja ter za ugotavljanje njihovega odzivanja kot funkcije fotonske energije - 4. del: Kalibriranje zunanjih in osebnih dozimetrov v območjih z nizko energijo rentgenskega referenčnega sevanja (ISO 4037-4:2019)

General Information

Status
Published
Public Enquiry End Date
16-Dec-2020
Publication Date
21-Feb-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
18-Feb-2021
Due Date
25-Apr-2021
Completion Date
22-Feb-2021

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SLOVENSKI STANDARD
SIST EN ISO 4037-4:2021
01-april-2021
Radiološka zaščita - Referenčno sevanje z rentgenskimi in gama žarki za
kalibracijo dozimetrov in merilnikov doze sevanja ter za ugotavljanje njihovega

odzivanja kot funkcije fotonske energije - 4. del: Kalibriranje zunanjih in osebnih

dozimetrov v območjih z nizko energijo rentgenskega referenčnega sevanja (ISO
4037-4:2019)

Radiological protection - X and gamma reference radiation for calibrating dosemeters

and doserate meters and for determining their response as a function of photon energy -

Part 4: Calibration of area and personal dosemeters in low energy X reference radiation

fields (ISO 4037-4:2019)

Strahlenschutz - Röntgen- und Gamma-Referenzstrahlungsfelder zur Kalibrierung von

Dosimetern und Dosisleistungsmessgeräten und zur Bestimmung ihres

Ansprechvermögens als Funktion der Photonenenergie - Teil 4: Kalibrierung von Orts-

und Personendosimetern in niedrigenergetischen Röntgen-Referenzstrahlungsfeldern
(ISO 4037-4:2019)
Radioprotection - Rayonnements X et gamma de référence pour l'étalonnage des

dosimètres et des débitmètres et pour la détermination de leur réponse en fonction de

l'énergie des photons - Partie 4: Étalonnage des dosimètres de zone et individuels dans

des champs de référence X de faible énergie (ISO 4037-4:2019)
Ta slovenski standard je istoveten z: EN ISO 4037-4:2021
ICS:
13.280 Varstvo pred sevanjem Radiation protection
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 4037-4:2021 en,fr,de

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

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SIST EN ISO 4037-4:2021
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SIST EN ISO 4037-4:2021
EN ISO 4037-4
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2021
EUROPÄISCHE NORM
ICS 17.240
English Version
Radiological protection - X and gamma reference radiation
for calibrating dosemeters and doserate meters and for
determining their response as a function of photon energy
- Part 4: Calibration of area and personal dosemeters in
low energy X reference radiation fields (ISO 4037-4:2019)

Radioprotection - Rayonnements X et gamma de Strahlenschutz - Röntgen- und Gamma-

référence pour l'étalonnage des dosimètres et des Referenzstrahlungsfelder zur Kalibrierung von

débitmètres et pour la détermination de leur réponse Dosimetern und Dosisleistungsmessgeräten und zur

en fonction de l'énergie des photons - Partie 4: Bestimmung ihres Ansprechvermögens als Funktion

Étalonnage des dosimètres de zone et individuels dans der Photonenenergie - Teil 4: Kalibrierung von Orts-

des champs de référence X de faible énergie (ISO 4037- und Personendosimetern in niedrigenergetischen

4:2019) Röntgen-Referenzstrahlungsfeldern (ISO 4037-4:2019)
This European Standard was approved by CEN on 18 January 2021.

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

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

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

member.

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

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

Centre has the same status as the official versions.

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

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

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

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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4037-4:2021 E

worldwide for CEN national Members.
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SIST EN ISO 4037-4:2021
EN ISO 4037-4:2021 (E)
Contents Page

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

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SIST EN ISO 4037-4:2021
EN ISO 4037-4:2021 (E)
European foreword

The text of ISO 4037-4:2019 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 4037-4:2021 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 August 2021, and conflicting national standards shall

be withdrawn at the latest by August 2021.

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

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

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, France, Germany, Greece, Hungary, Iceland,

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

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

United Kingdom.
Endorsement notice

The text of ISO 4037-4:2019 has been approved by CEN as EN ISO 4037-4:2021 without any

modification.
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SIST EN ISO 4037-4:2021
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SIST EN ISO 4037-4:2021
INTERNATIONAL ISO
STANDARD 4037-4
Second edition
2019-01
Radiological protection — X and
gamma reference radiation for
calibrating dosemeters and doserate
meters and for determining their
response as a function of photon
energy —
Part 4:
Calibration of area and personal
dosemeters in low energy X reference
radiation fields
Radioprotection — Rayonnements X et gamma de référence
pour l'étalonnage des dosimètres et des débitmètres et pour la
détermination de leur réponse en fonction de l'énergie des photons —
Partie 4: Étalonnage des dosimètres de zone et individuels dans des
champs de référence X de faible énergie
Reference number
ISO 4037-4:2019(E)
ISO 2019
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols (and abbreviated terms) ...................................................................................................................................................... 2

5 General procedures for calibrating and determining response ......................................................................... 3

6 Characterisation and production of low energy X-ray reference radiations .........................................3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Tube potential .......................................................................................................................................................................................... 4

6.3 Spectral fluence and conversion coefficients ................................................................................................................ 4

7 Dosimetry of low energy reference radiations ..................................................................................................................... 4

7.1 General ........................................................................................................................................................................................................... 4

7.2 Stability check facility ....................................................................................................................................................................... 4

8 Calibration and determination of the response as a function of photon energy and

angle of radiation incidence ..................................................................................................................................................................... 4

8.1 General ........................................................................................................................................................................................................... 4

8.2 Selection of calibration method ............................................................................................................................................... 5

8.3 Calibration by using reference instruments for K ................................................................................................. 5

8.3.1 General...................................................................................................................................................................................... 5

8.3.2 Conventional quantity value of the air kerma ........................................................................................ 5

8.3.3 Conventional quantity value of the dose equivalent quantities H (0,07)

and H'(0,07) ......................................................................................................................................................................... 6

8.3.4 Conventional quantity value of the dose equivalent quantities H (10) or

H*(10) and H (3) or H'(3) ....................................................................................................................................... 6

8.3.5 Performing the calibration ...................................................................................................................................... 8

8.4 Calibration by using reference instruments which measure the ICRU dose

equivalent quantities ......................................................................................................................................................................... 8

8.4.1 General...................................................................................................................................................................................... 8

8.4.2 Conventional quantity value of the dose equivalent quantities H (10) or

H*(10) and H (3) or H'(3) ....................................................................................................................................... 9

8.4.3 Performing the calibration ...................................................................................................................................10

8.5 Statement of uncertainty .............................................................................................................................................................11

Annex A (normative) Correction for air density ...................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................18

© ISO 2019 – All rights reserved iii
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/iso/foreword .html.

This document 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 4037-4:2004), which has been technically

revised.
A list of all the parts in the ISO 4037 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)
Introduction

The maintenance release of this document adjusts this fourth part to the second edition of the first

three parts. This includes the improvements on high voltage generators from 1996 to 2017 (e.g., the

use of high frequency switching supplies providing nearly constant potential), and the spectral

measurements at irradiation facilities equipped with such generators (e.g., the catalogue of X-ray

[1]

spectra by Ankerhold ). It also incorporates all published information with the aim to adjust the

requirements for the technical parameters of the reference fields to the targeted overall uncertainty of

about 6 % to 10 % for the phantom related operational quantities of the International Commission on

[2]

Radiation Units and Measurements (ICRU) . It does not change the concept of ISO 4037.

ISO 4037, focusing on photon reference radiation fields, is divided into four parts. ISO 4037-1 gives the

methods of production and characterization of reference radiation fields in terms of the quantities

photon fluence and air kerma free-in-air. ISO 4037-2 describes the dosimetry of the reference radiation

qualities in terms of air kerma and in terms of the phantom related operational quantities of the

[2]

International Commission on Radiation Units and Measurements (ICRU) . ISO 4037-3 describes the

methods for calibrating and determining the response of dosemeters and doserate meters in terms of

[2]

the operational quantities of the ICRU . This document gives special considerations and additional

requirements for calibration of area and personal dosemeters in low energy X reference radiation fields,

which are reference fields with generating potential lower or equal to 30 kV.

The general procedures described in ISO 29661 including Amendment 1 are used as far as possible in

this document. In addition, the symbols used are in line with ISO 29661.

NOTE For irradiation of the whole body, H (10) and H*(10) are relevant for radiation protection, as long as

they are closer to their limit than H′(0,07) and H (0,07). This is the case down to about 15 keV.

© ISO 2019 – All rights reserved v
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SIST EN ISO 4037-4:2021
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SIST EN ISO 4037-4:2021
INTERNATIONAL STANDARD ISO 4037-4:2019(E)
Radiological protection — X and gamma reference
radiation for calibrating dosemeters and doserate meters
and for determining their response as a function of photon
energy —
Part 4:
Calibration of area and personal dosemeters in low energy
X reference radiation fields
1 Scope

This document gives guidelines on additional aspects of the characterization of low energy photon

radiations and on the procedures for calibration and determination of the response of area and personal

dose(rate)meters as a function of photon energy and angle of incidence. This document concentrates

on the accurate determination of conversion coefficients from air kerma to H (10), H*(10), H (3) and

p p

H'(3) and for the spectra of low energy photon radiations. As an alternative to the use of conversion

coefficients the direct calibration in terms of these quantities by means of appropriate reference

instruments is described.
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.

ISO 4037-1, Radiological protection — X and gamma reference radiation for calibrating dosemeters and

doserate meters and for determining their response as a function of photon energy — Part 1: Radiation

characteristics and production methods

ISO 4037-2:2019, Radiological protection — X and gamma reference radiation for calibrating dosemeters

and doserate meters and for determining their response as a function of photon energy — Part 2: Dosimetry

for radiation protection over the energy ranges from 8 keV to 1,3 MeV and 4 MeV to 9 MeV

ISO 4037-3:2019, Radiological protection — X and gamma reference radiation for calibrating dosemeters

and doserate meters and for determining their response as a function of photon energy — Part 3: Calibration

of area and personal dosemeters and the measurement of their response as a function of energy and angle

of incidence

ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in

me a s ur ement (GUM: 1995)

ISO 29661, Reference radiation fields for radiation protection — Definitions and fundamental concepts

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4037-1, ISO 29661 and the

following apply.

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
© ISO 2019 – All rights reserved 1
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
low energy X-ray reference radiation
all radiation qualities with nominal tube potentials up to and including 30 kV

Note 1 to entry: These radiation qualities are as specified in ISO 4037-1 and all continuous reference filtered X

radiations.
4 Symbols (and abbreviated terms)
The symbols (and abbreviated terms) used are given in Table 1.
Table 1 — Symbols (and abbreviated terms)
Symbol Meaning Unit
ρ air density kg/m
3 3
ρ air density under reference conditions: ρ = 1,197 4 kg/m kg/m
0 0
ρ air density prevailing during irradiation kg/m
irr

ρ air density prevailing during determination of the conventional quantity value of kg/m

con
the measurand
ρ air density prevailing during calibration of the instrument kg/m
cal
ρ air density prevailing during calibration of the monitor chamber kg/m
ρ air density prevailing during the spectral measurements kg/m
spec
Δρ change of air density kg/m
α angle of radiation incidence to the normal of the phantom surface deg
Δα change of angle of radiation incidence deg
U tube potential V
ΔU change in tube potential V
T air temperature K

T air temperature under reference conditions: T = 293,15 K (equivalent to 20 °C), K

0 0
r relative air humidity —

r relative air humidity under reference conditions: r = 0,65 (equivalent to 65 %) —

0 0
p air pressure kPa
p air pressure under reference conditions: p = 101,3 kPa kPa
0 0
m gradient of the gradient m(d ) m /kg
d air
m(d ) gradient for distance d m /kg
air air
m(1,0 m) gradient for distance 1,0 m m /kg
K air kerma free-in-air Gy
k(ρ, M) air density correction factor for measurand M —
H (10) personal dose equivalent at 10 mm depth Sv
H (3) personal dose equivalent at 3 mm depth Sv
H (0,07) personal dose equivalent at 0,07 mm depth Sv
H*(10) ambient dose equivalent at 10 mm depth Sv
H'(3) directional dose equivalent at 3 mm depth Sv
H'(0,07) directional dose equivalent at 0,07 mm depth Sv

h (10; α) conversion coefficient from K to H (10) for angle of radiation incidence α Sv/Gy

pK a p
h* (10) conversion coefficient from K to H*(10) Sv/Gy
p a

h (3; α) conversion coefficient from K to H (3) for angle of radiation incidence α Sv/Gy

pK a p
2 © ISO 2019 – All rights reserved
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)
Table 1 (continued)
Symbol Meaning Unit
E photon energy eV
d distance from the beam exit window of the X-ray tube to the monitor chamber m
d distance from the beam exit window of the X-ray tube to the point of test m
air
–2 –1
Φ (E) spectral fluence at the photon energy E m eV
N number of pulses generated in the detector —
Q charge Q generated in the detector by one photon C
2 –1
R(E, Q) response function m C
5 General procedures for calibrating and determining response

In ISO 4037-2, two methods are given to determine the phantom related dose equivalent quantities

for low energy X reference fields. Both methods require a reference field according to ISO 4037-1. The

first method, method I, requires the dosimetry with respect to air kerma free-in-air and after that, the

selected operational quantity is derived by the application of a conversion coefficient that relates the

air kerma free-in-air to the selected operational quantity. For matched reference fields this conversion

coefficient is taken from ISO 4037-3, for characterized reference fields the conversion coefficient

is determined using spectrometry. For the dose-equivalent quantities H'(0,07) and H (0,07), this

procedure is associated with only a small additional uncertainty, because the conversion coefficients

depend only slightly on the photon energy and angle of radiation incidence for the ranges given in

ISO 4037-3. Therefore, for these dose equivalent quantities, no special attention is needed for the low

energy X reference radiation fields. For the four other dose equivalent quantities H (10), H*(10), H (3)

p p

and H′(3) this is different. For them, the use of conversion coefficients can be associated with large

additional uncertainties if low energy X reference radiation fields are considered. This is because the

conversion coefficients depend strongly on the photon energy and the angle of radiation incidence.

A detailed description of all the measurements and methods necessary to avoid these additional

[3][4] [5]
uncertainties is given by Ankerhold et al. and by Behrens .

The second method, method II, to determine the phantom related dose quantities is based on the use

of (secondary) standards directly calibrated in terms of these dose equivalent quantities. This method

can also be used for all non-validated radiation qualities, for which the recommended conversion

coefficients cannot be used. This method is described in ISO 4037-2:2019, Clause 6.

If the reference field cannot be validated, then, method I can still be used if a spectrometer is used

to measure the spectrum of the radiation quality under consideration. From this spectrum, the

specific conversion coefficient can be calculated and applied to the measured value of the air kerma K

free-in-air.

This document defines the conditions that shall be met to use one of the two methods and the

experimental steps to be used for the selected method. If a monitor chamber (see ISO 4037-2:2019, 9.2)

is used as a transfer device additional corrections shall be applied for differences in the air density

prevailing during calibration of the monitor chamber and during calibration of the instrument under

test. The standard does not give advice on the construction of the instruments necessary for both ways.

[3]

Examples for the instruments and the experimental steps for both ways are given by Ankerhold et al.

[4] [5] [6]
, Behrens and Duftschmid et al. .
6 Characterisation and production of low energy X-ray reference radiations
6.1 General

This subclause specifies the characteristics by which a laboratory can produce the reference filtered

X radiations specified in ISO 4037-1 for the given purposes. For various influence quantities, data are

given on the required stability of these influence quantities. These data indicate how large the change

in value of these influence quantities can be until a change of the measurand of 2 % is caused. These

© ISO 2019 – All rights reserved 3
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SIST EN ISO 4037-4:2021
ISO 4037-4:2019(E)

data shall either be interpreted as limits for the deviation from its nominal value or, where possible, as

a criterion for the necessity of corrections.

The requirements given in ISO 4037-1:2019, 4.2, consider partly the special requirements for low

energy reference radiations for the quantities H (10) or H*(10). These special requirements are, to less

extent, also valid for the dose equivalent quantities H′(3), H (3). Therefore, this document focuses on

the quantities H (10) or H*(10) and assumes that for the dose equivalent quantities H′(3), H (3) nearly

p p
the same requirements are valid.
6.2 Tube potential

This subclause is relevant for method I and method II. The dose equivalent quantities H (10), H*(10),

H (3) and H′(3) are for low energy X radiation more sensitive to the tube potential than the air kerma,

K , free-in-air. The requirements on the tube potential given in ISO 4037-1:2019, Table 7 are valid. This

Table 7 gives values for the change of tube potential that cause a change in the value of the conversion

coefficient of 2 % if all other parameters are unchanged.
6.3 Spectral fluence and conversion coefficients

This subclause is relevant for method I only. Knowledge of the spectral fluence is necessary to determine

the conversion coefficient from air kerma to the measurand for every radiation quality of the X-ray

facility. In ISO 4037-2:2019, Annex B, an example for the determination of the spectral fluence is given.

The spectral fluence is
...

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