SIST-TS CEN ISO/TS 18090-1:2019

Radiological protection - Characteristics of reference pulsed radiation - Part 1: Photon radiation (ISO/TS 18090-1:2015)

ISO/TS 18090-1:2015 is directly applicable to pulsed X-radiation with pulse duration of 0,1 ms up to 10 s. This covers the whole range used in medical diagnostics at the time of publication. Some specifications may also be applicable for much shorter pulses; one example is the air kerma of one pulse. Such a pulse may be produced, e.g. by X-ray flash units or high-intensity femtosecond-lasers. Other specifications are not applicable for much shorter pulses; one example is the time-dependent behaviour of the air kerma rate. This may not be measurable for technical reasons as no suitable instrument is available, e.g. for pulses produced by a femtosecond-laser.
ISO/TS 18090-1:2015 specifies the characteristics of reference pulsed radiation for calibrating and testing radiation protection dosemeters and dose rate meters with respect to their response to pulsed radiation. The radiation characteristics includes the following:
a)    time-dependent behaviour of the air kerma rate of the pulse;
b)    time-dependent behaviour of the X-ray tube high voltage during the pulse;
c)    uniformity of the air kerma rate within a cross-sectional area of the radiation beam;
d)    air kerma of one radiation pulse;
e)    air kerma rate of the radiation pulse;
f)     repetition frequency.
ISO/TS 18090-1:2015 does not define new radiation qualities. Instead, it uses those radiation qualities specified in existing ISO and IEC standards. This part of ISO/TS 18090 gives the link between the parameters for pulsed radiation and the parameters for continuous radiation specifying the radiation qualities. It does not specify specific values or series of values for the pulsed radiation field but specifies only those limits for the relevant pulsed radiation parameters that are required for calibrating dosemeters and dose rate meters and for determining their response depending on the said parameters.
The pulse parameters with respect to the phantom-related quantities were determined using conversion coefficients according to ISO 4037 (all parts). This is possible as the radiation qualities specified in existing ISO and IEC standards are used.
A given reference pulsed X-ray facility is characterized by the parameter ranges over which the full specifications and requirements according to this part of ISO/TS 18090 are met. Therefore, not all reference pulsed X-ray facilities can produce pulses covering the same parameter ranges.

Strahlenschutz - Eigenschaften gepulster Referenzstrahlung - Teil 1: Photonenstrahlung (ISO/TS 18090-1:2015)

Dieser Teil von ISO/TS 18090 ist direkt auf gepulste Röntgenstrahlung mit Pulsdauern von 0,1 ms bis 10 s anwendbar. Zur Zeit seiner Veröffentlichung überdeckt er den gesamten in der medizinischen Diagnostik verwendeten Bereich. Einige Spezifikationen können auch für viel kürzere Pulse anwendbar sein, ein Beispiel ist die Luftkerma eines Pulses. Ein derartiger Puls kann z. B. von einem Röntgenblitzgerät oder durch hoch-intensive Femtosekunden-Laser erzeugt werden. Andere Spezifikationen können nicht auf viel kürzere Pulse angewendet werden; ein Beispiel ist das zeitabhängige Verhalten der Luftkermaleistung. Diese kann aus technischen Gründen unmessbar sein, da es keine geeigneten Geräte gibt, z. B. für die von einem Femto-sekunden-Laser erzeugten Pulse.
Dieser Teil von ISO/TS 18090 legt die Charakteristika von gepulster Referenzstrahlung fest, die für die Kalib-rierung und Prüfung von Dosimetern und Dosisleistungsmessgeräten für den Strahlenschutz verwendet wird, um deren Ansprechvermögen hinsichtlich gepulster Strahlung zu bestimmen. Zu den Charakteristika der Strahlung gehören:
a)   das zeitabhängige Verhalten der Luftkermaleistung des Pulses;
b)   das zeitabhängige Verhalten der Hochspannung der Röntgenröhre während des Pulses;
c)   die Gleichmäßigkeit der Luftkermaleistung innerhalb der Querschnittsfläche des Strahlenbündels;
d)   die Luftkerma eines Strahlungspulses;
e)   die Luftkermaleistung des Strahlungspulses;
f)   die Pulsfrequenz.
Dieser Teil von ISO/TS 18090 definiert keine neuen Strahlungsqualitäten. Stattdessen verwendet er diejeni¬gen Strahlungsqualitäten, die in vorhandenen ISO- bzw. IEC-Normen spezifiziert sind. Dieser Teil von ISO/TS 18090 gibt die Verbindung zwischen den Parametern für gepulste Strahlung und den Parametern für kontinuierliche Strahlung an, mit denen die Strahlungsqualitäten spezifiziert sind. Er legt keine speziellen Werte oder Serien von Werten für das gepulste Strahlungsfeld fest, sondern legt nur jene Grenzen für die relevanten Parameter des gepulsten Strahlungsfeldes fest, die für die Kalibrierung von Dosimetern und Dosisleistungs-Messgeräten benötigt werden, um ihr Ansprechvermögen hinsichtlich gepulster Strahlung in Abhängigkeit von den genannten Parametern zu bestimmen.
Die Pulsparameter in Bezug auf die phantombezogenen Messgrößen werden unter Verwendung von Konver-sionskoeffizienten nach ISO 4037 (alle Teile) bestimmt. Dies ist möglich, da die in existierenden ISO- und IEC-Normen spezifizierten Strahlungsqualitäten verwendet werden.
Eine vorhandene Röntgen-Referenzanlage für gepulste Strahlung wird durch die Parameterbereiche charak-terisiert, für die alle Spezifikationen und Anforderungen nach diesem Teil von ISO/TS 18090 eingehalten werden. Deshalb können nicht alle Röntgen-Referenzanlagen für gepulste Strahlung Pulse produzieren, die die gleichen Parameterbereiche abdecken.

Radioprotection - Caractéristiques des champs de rayonnement pulsés de référence - Partie 1: Radiation de photons (ISO/TS 18090-1:2015)

L'ISO/TS 18090-1:2015 s'applique directement au rayonnement X pulsé ayant une durée d'impulsion comprise entre 0,1 ms et 10 s. Cela couvre toute la gamme utilisée en diagnostic médical au moment de la publication. Certaines spécifications peuvent également s'appliquer à des impulsions beaucoup plus courtes; un exemple est le kerma dans l'air d'une impulsion. Une telle impulsion peut être produite, par exemple, par des générateurs de rayons X « éclair » ou des lasers femtoseconde intenses. D'autres spécifications ne s'appliquent pas aux impulsions beaucoup plus courtes; un exemple est le comportement du débit kerma dans l'air en fonction du temps. Il se peut qu'il ne soit pas mesurable pour des raisons techniques, car aucun instrument approprié n'est disponible, par exemple pour des impulsions produites par un laser femtoseconde.
L'ISO/TS 18090-1:2015 spécifie les caractéristiques d'un rayonnement pulsé de référence pour l'étalonnage et les essais de dosimètres de radioprotection et de débitmètres de dose par rapport à leur réponse à un rayonnement pulsé. Les caractéristiques du rayonnement comprennent ce qui suit:
a)    le comportement en fonction du temps du débit de kerma dans l'air de l'impulsion;
b)    le comportement en fonction du temps de la haute tension du tube à rayons X pendant l'impulsion;
c)    l'uniformité du débit de kerma dans l'air dans une section transversale du faisceau de rayonnement;
d)    le kerma dans l'air d'une impulsion de rayonnement;
e)    le débit de kerma dans l'air de l'impulsion de rayonnement;
f)     la fréquence de répétition.
L'ISO/TS 18090-1:2015 ne définit pas de nouvelles qualités de rayonnement. Au lieu de cela, elle utilise les qualités de rayonnement spécifiées dans les normes ISO et IEC existantes. L'ISO/TS 18090-1:2015 indique la relation entre les paramètres relatifs à un rayonnement pulsé et les paramètres relatifs à un rayonnement continu spécifiant les qualités de rayonnement. Elle ne stipule pas de valeurs spécifiques ni de séries de valeurs pour le champ de rayonnement pulsé, mais spécifie uniquement les limites pour les paramètres pertinents de rayonnement pulsé qui sont requis pour l'étalonnage des dosimètres et des débitmètres de dose et pour la détermination de leur réponse en fonction desdits paramètres.

Radiološka zaščita - Značilnosti referenčnega impulznega sevanja - 1. del: Fotonsko sevanje (ISO/TS 18090-1:2015)

Standard ISO/TS 18090-1:2015 se neposredno uporablja za impulzno rentgensko sevanje s trajanjem impulza od 0,1 ms do 10 s. To zajema celoten nabor, ki se v času objave uporablja v medicinski diagnostiki. Nekatere specifikacije se lahko uporabljajo tudi za precej krajše impulze; primer je kerma v zraku enega impulza. Takšen impulz lahko proizvedejo na primer enote za generiranje rentgenskih žarkov ali visoko intenzivni femtosekundni laserji. Druge specifikacije se ne uporabljajo za precej krajše impulze; primer je časovno odvisno vedenje stopnje kerme v zraku. Tega morda ni mogoče izmeriti iz tehničnih razlogov, saj primerni inštrumenti niso na voljo, npr. za impulze, ki jih proizvede femtosekundni laser.
Standard ISO/TS 18090-1:2015 določa značilnosti referenčnega impulznega sevanja za umerjanje ter preskušanje dozimetrov za zaščito pred sevanjem in merilnikov odmerkov v zvezi z njihovim odzivom na impulzno sevanje. Značilnosti sevanja vključujejo naslednje:
a) časovno odvisno vedenje stopnje kerme v zraku impulza;
b) časovno odvisno vedenje visoke napetosti rentgenske cevi med impulzom;
c) enakomernost stopnje kerme v zraku v prečnem prerezu radiološkega žarka;
d) kerma v zraku enega impulza sevanja;
e) stopnja kerme v zraku impulza sevanja;
f) pogostost ponovitve.
Standard ISO/TS 18090-1:2015 ne določa novih kakovosti sevanja. Namesto tega uporablja kakovosti sevanja, ki so določene v obstoječih standardih ISO in IEC. Ta del standarda ISO/TS 18090 podaja povezavo med parametri impulznega sevanja in parametri neprekinjenega sevanja ter tako določa kakovosti sevanja. Ne določa posebnih vrednosti ali nabora vrednosti za področje impulznega sevanja, ampak določa samo tiste mejne vrednosti za zadevne parametre impulznega sevanja, ki so zahtevani za umerjanje dozimetrov in merilnikov odmerkov ter za določanje odziva glede na navedene parametre.
Impulzni parametri v zvezi s fantomskimi količinami so bili določeni s pomočjo koeficientov pretvorbe v skladu s standardom ISO 4037 (vsi deli). To je mogoče, ker se uporabljajo kakovosti sevanja, ki so določene v obstoječih standardih ISO in IEC.
Za podano referenčno impulzno rentgensko opremo je značilno, da razponi parametrov presegajo vrednosti, za katere so izpolnjenje celotne specifikacije in zahteve v skladu s tem delom standarda ISO/TS 18090. Zato nekatera referenčna impulzna rentgenska oprema ne more proizvajati impulzov, ki zajemajo iste razpone parametrov.

General Information

• Status: Published
• Public Enquiry End Date: 10-Jul-2019
• Publication Date: 22-Sep-2019
• ICS: 13.280 - Radiation protection
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-Sep-2019
• Due Date: 24-Nov-2019
• Completion Date: 23-Sep-2019
• Ref Project: CEN ISO/TS 18090-1:2019 - Radiological protection - Characteristics of reference pulsed radiation - Part 1: Photon radiation (ISO/TS 18090-1:2015)

Relations

• Revised: oSIST prEN ISO 18090-1:2025 - Radiological protection - Characteristics of reference pulsed radiation - Part 1: Photon radiation (ISO/DIS 18090-1:2025)
• Effective Date: 04-Oct-2023

Overview

CEN ISO/TS 18090-1:2019 (ISO/TS 18090-1:2015) defines the characteristics of reference pulsed photon radiation used for calibrating and testing radiation protection dosemeters and dose rate meters. It is directly applicable to pulsed X‑radiation with pulse durations from 0.1 ms to 10 s, covering the pulse range commonly used in medical diagnostics at the time of publication. The document links pulsed-radiation parameters to established continuous-radiation qualities from existing ISO and IEC standards rather than creating new radiation qualities.

Key topics and technical requirements

The Technical Specification sets out the parameters and test methods needed to characterize a reference pulsed X‑ray field for dosimetry calibration. Principal topics include:

• Time-dependent air kerma rate of the pulse - requirements, measurement methods and interpretation.
• Time-dependent X‑ray tube high‑voltage behaviour during the pulse - measurement and acceptance criteria.
• Spatial uniformity of the air kerma rate across the beam cross section.
• Air kerma of a single pulse and air kerma rate of the pulse.
• Pulse repetition frequency for repeated pulses.
• Use of an equivalent trapezoidal pulse concept to relate pulse shape to air kerma and air kerma rate.
• Requirements for constancy of air kerma rate during the pulse plateau.
• Dosimetry-specific tests: instrument response vs. air kerma rate, sensitive volume effects, and methods to determine pulse dose and dose‑rate quantities.

Important notes and limitations:

• The standard does not prescribe specific numerical radiation quality values for pulsed fields; it specifies limits and criteria required for calibration.
• Some specifications may be inapplicable to very short pulses (e.g., femtosecond lasers) where time‑dependent measurements are technically infeasible.
• Annexes cover practical measurement equipment and methods (e.g., diode detectors) and the determination of equivalent trapezoid pulses.

Applications and users

This Technical Specification is intended for:

• Calibration laboratories and national metrology institutes establishing pulsed reference fields.
• Medical physicists and clinical engineers working with pulsed diagnostic X‑ray systems.
• Manufacturers and testers of dosemeters and dose rate meters validating instrument response to pulsed radiation.
• Radiation protection professionals and accreditation bodies creating test protocols and acceptance criteria for pulsed-field dosimetry.

Practical uses include setting up reference pulsed X‑ray facilities, defining parameter ranges over which a facility meets the specification, and performing instrument calibration and type testing for pulsed radiation environments.

Related standards

• Uses radiation qualities specified in existing ISO and IEC standards (no new qualities defined).
• Pulse-to-phantom conversions and dose coefficients reference ISO 4037 (all parts).
• Developed under ISO/TC 85 (Radiological protection) and adopted by CEN for European application.

Keywords: ISO/TS 18090-1, CEN ISO/TS 18090-1:2019, pulsed X‑radiation, radiological protection, air kerma, dosemeter calibration, pulsed photon radiation, dose rate meters.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2019
Radiološka zaščita - Značilnosti referenčnega impulznega sevanja - 1. del:
Fotonsko sevanje (ISO/TS 18090-1:2015)
Radiological protection - Characteristics of reference pulsed radiation - Part 1: Photon
radiation (ISO/TS 18090-1:2015)
Strahlenschutz - Eigenschaften gepulster Referenzstrahlung - Teil 1: Photonenstrahlung
(ISO/TS 18090-1:2015)
Radioprotection - Caractéristiques des champs de rayonnement pulsés de référence -
Partie 1: Radiation de photons (ISO/TS 18090-1:2015)
Ta slovenski standard je istoveten z: CEN ISO/TS 18090-1:2019
ICS:
13.280 Varstvo pred sevanjem Radiation protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN ISO/TS 18090-1
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
September 2019
TECHNISCHE SPEZIFIKATION
ICS 13.280
English Version
Radiological protection - Characteristics of reference
pulsed radiation - Part 1: Photon radiation (ISO/TS 18090-
1:2015)
Radioprotection - Caractéristiques des champs de Strahlenschutz - Eigenschaften gepulster
rayonnement pulsés de référence - Partie 1: Radiation Referenzstrahlung - Teil 1: Photonenstrahlung (ISO/TS
de photons (ISO/TS 18090-1:2015) 18090-1:2015)
This Technical Specification (CEN/TS) was approved by CEN on 12 August 2019 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, 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 18090-1:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO/TS 18090-1:2015 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 CEN ISO/TS 18090-1:2019 by Technical Committee
CEN/TC 430 “Nuclear energy, nuclear technologies, and radiological protection” the secretariat of
which is held by AFNOR.
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/TS 18090-1:2015 has been approved by CEN as CEN ISO/TS 18090-1:2019 without any
modification.
TECHNICAL ISO/TS
SPECIFICATION 18090-1
First edition
2015-08-01
Radiological protection —
Characteristics of reference pulsed
radiation —
Part 1:
Photon radiation
Radioprotection — Caractéristiques des champs de rayonnement
pulsés de référence —
Partie 1: Radiation de photons
Reference number
ISO/TS 18090-1:2015(E)
©
ISO 2015
ISO/TS 18090-1:2015(E)
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

ISO/TS 18090-1:2015(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Characteristics of reference pulsed radiation . 5
4.1 General . 5
4.2 Time-dependent air kerma rate characteristics of the radiation pulse . 5
4.2.1 Requirements . 5
4.2.2 Method of test . 6
4.2.3 Interpretation of the results . 7
4.3 Time-dependent high voltage characteristics of the radiation pulse . 7
4.3.1 Requirement . 7
4.3.2 Method of test . 7
4.3.3 Interpretation of the results . 7
4.4 Space dependent air kerma characteristics of the radiation pulse. 7
4.4.1 Requirement on field uniformity across the beam area . 7
4.4.2 Method of test . 7
4.4.3 Interpretation of the results . 8
4.5 Filtration . 8
4.6 Equivalence of measured radiation pulse and trapezoidal pulse . . 8
4.6.1 Requirements . 8
4.6.2 Method of test . 8
4.6.3 Interpretation of the results . 8
4.7 Constancy of air kerma rate during the pulse plateau time . 9
4.7.1 Requirement . 9
4.7.2 Method of test . 9
4.7.3 Interpretation of results . 9
5 Dosimetry of pulsed reference radiation .11
5.1 General requirements on the instrument .11
5.2 Air kerma rate dependence of the instrument response .11
5.2.1 General.11
5.2.2 Requirement .11
5.2.3 Method of test and interpretation of the results .11
5.3 Size of the sensitive volume of the instrument .12
5.4 Air kerma of the radiation pulse .12
5.5 Dose equivalent of the radiation pulse .12
5.6 Radiation pulse air kerma rate .12
5.7 Radiation pulse dose equivalent rate .12
Annex A (informative) Diode-detector and associated amplifier .13
Annex B (informative) Determination of the equivalent trapezoid radiation pulse .15
Bibliography .17
ISO/TS 18090-1:2015(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 2, Radiological protection.
ISO/TS 18090 consists of the following parts, under the general title Radiological protection —
Characteristics of reference pulsed radiation:
— Part 1: Photon radiation
iv © ISO 2015 – All rights reserved

ISO/TS 18090-1:2015(E)
Introduction
The specification and determination of the special characteristics required for radiation protection
dosemeters to be used in pulsed fields of ionizing radiation have been excluded from all International
Standards for personal and environmental dosemeters issued so far. Due to the increased use of pulsed
radiation in medicine and industry, such International Standards are currently under development. A
prerequisite for such International Standards is the availability of the required reference fields for pulsed
radiation. This Technical Specification provides the necessary information for such reference fields.
The concept is based on the existing standards for radiation qualities defined in ISO and IEC standards.
It only adds the parameters of the pulsed field and gives some guidance for their determination.
Therefore, no new radiation qualities are defined, only the link between the parameters for pulsed
radiation and the parameters for continuous radiation are given. The main required parameters for
pulsed radiation fields are the following:
— radiation pulse duration, t ;
pulse

— radiation pulse air kerma rate, K ;
a,pulse
— air kerma per radiation pulse, K ;
a,pulse
— for repeated pulses, their repetition frequency, f .
pulse
The pulse parameters were determined by using an equivalent trapezoidal radiation pulse, which is
equivalent with respect to air kerma and air kerma rate. Reference pulsed radiation is characterized by
specified maximum deviations of the given pulse from the equivalent trapezoidal radiation pulse and
by requirements concerning the change of radiation quality during the given radiation pulse.
The pulse parameters with respect to the phantom related quantities were determined using conversion
coefficients according to ISO 4037 (all parts).
This publication contains information for which worldwide experience is not available at the date
of its development. Therefore, it was decided to publish it as a Technical Specification. It is expected
that within the following years, experience will be gained and the maintenance of this Technical
Specification could lead to an International Standard.
TECHNICAL SPECIFICATION ISO/TS 18090-1:2015(E)
Radiological protection — Characteristics of reference
pulsed radiation —
Part 1:
Photon radiation
1 Scope
This part of ISO/TS 18090 is directly applicable to pulsed X-radiation with pulse duration of 0,1 ms
up to 10 s. This covers the whole range used in medical diagnostics at the time of publication. Some
specifications may also be applicable for much shorter pulses; one example is the air kerma of one pulse.
Such a pulse may be produced, e.g. by X-ray flash units or high-intensity femtosecond-lasers. Other
specifications are not applicable for much shorter pulses; one example is the time-dependent behaviour
of the air kerma rate. This may not be measurable for technical reasons as no suitable instrument is
available, e.g. for pulses produced by a femtosecond-laser.
This part of ISO/TS 18090 specifies the characteristics of reference pulsed radiation for calibrating and
testing radiation protection dosemeters and dose rate meters with respect to their response to pulsed
radiation. The radiation characteristics includes the following:
a) time-dependent behaviour of the air kerma rate of the pulse;
b) time-dependent behaviour of the X-ray tube high voltage during the pulse;
c) uniformity of the air kerma rate within a cross-sectional area of the radiation beam;
d) air kerma of one radiation pulse;
e) air kerma rate of the radiation pulse;
f) repetition frequency.
This part of ISO/TS 18090 does not define new radiation qualities. Instead, it uses those radiation
qualities specified in existing ISO and IEC standards. This part of ISO/TS 18090 gives the link between
the parameters for pulsed radiation and the parameters for continuous radiation specifying the
radiation qualities. It does not specify specific values or series of values for the pulsed radiation field but
specifies only those limits for the relevant pulsed radiation parameters that are required for calibrating
dosemeters and dose rate meters and for determining their response depending on the said parameters.
The pulse parameters with respect to the phantom-related quantities were determined using
conversion coefficients according to ISO 4037 (all parts). This is possible as the radiation qualities
specified in existing ISO and IEC standards are used.
A given reference pulsed X-ray facility is characterized by the parameter ranges over which the full
specifications and requirements according to this part of ISO/TS 18090 are met. Therefore, not all
reference pulsed X-ray facilities can produce pulses covering the same parameter ranges.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO/TS 18090-1:2015(E)
ISO 4037-1:1996, 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 4037-2:1997, 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
IEC 60050-395:2014, International Electrotechnical Vocabulary — Part 395: Nuclear instrumentation:
Physical phenomena, basic concepts, instruments, systems, equipment and detectors
IEC 61267:2005, Medical diagnostic X-ray equipment — Radiation conditions for use in the determination
of characteristics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-395:2014 and the
following apply.
3.1
air kerma per radiation pulse
K
a, pulse
air kerma value of one radiation pulse at a point in the photon radiation field
3.2
continuous radiation
ionizing radiation with a constant dose rate at a given point in space
for time intervals longer than 10 s
3.3
dose equivalent per radiation pulse
H
pulse
dose equivalent value of one radiation pulse at a point in the photon radiation field
3.4
equivalent trapezoidal radiation pulse
trapezoidal radiation pulse that is considered to be equivalent to the given radiation pulse
3.5
field uniformity
F
uni
uniformity of the air kerma distribution determined across a defined area
KK−
a, pulse, maxa, pulse, min
F =−1
uni
KK
05, ×+
()
a, a,
pulse, max pulse, min
where
K is the maximum air kerma value attributed to one radiation pulse occurring across the
a, pulse, max
defined area;
K is the minimum air kerma value attributed to one radiation pulse occurring across the
a, pulse, min
defined area.
Note 1 to entry: The defined area can be the whole beam diameter or only parts of it, e.g. those covered by the
dosemeter under test.
Note 2 to entry: Full field uniformity is equivalent to F = 1. No field uniformity, that is a variation of K
uni a, pulse
between 0 and K , is equivalent to F = 0.
a, pulse, max uni
2 © ISO 2015 – All rights reserved

ISO/TS 18090-1:2015(E)
3.6
pulse peak mean voltage
U
pulse, peak, mean
mean value of the sequence of X-ray tube voltages, U , measured during the radiation pulse peak time
i
n
peak
U = U
∑
pulse, peak, mean i
n
peak
i=1
where
U is the i-th measured value;
i
n is the number of measurements of the X-ray tube voltage.
peak
3.7
pulse repetition frequency
f
pulse
number of pulses in a periodic pulse train divided by the duration of the train
[SOURCE: IEV 702-03-07, modified]
Note 1 to entry: This version of this part of ISO/TS 18090 deals only with single pulses, but it might be extended
in the future to repeated pulses, therefore, this definition is already given here.
3.8
pulse train
discrete sequence of a finite number of pulses
[SOURCE: IEV 702-03-11, modified]
Note 1 to entry: The sequence can be periodic or non-periodic.
3.9
pulsed radiation
ionizing rad
...