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.

Kabelnetze für Fernsehsignale, Tonsignale und interaktive Dienste - Teil 3-3: Aktive Breitbandgeräte für Kabelnetze - Messverfahren für den maximalen Betriebs-Ausgangspegel im Rückweg (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
Publication Date
10-Sep-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
11-Sep-2019
Completion Date
11-Sep-2019

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SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 18090-1:2019
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
SIST-TS CEN ISO/TS 18090-1:2019 en,fr,de

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

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SIST-TS CEN ISO/TS 18090-1:2019
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SIST-TS CEN ISO/TS 18090-1:2019
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.
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SIST-TS CEN ISO/TS 18090-1:2019
CEN ISO/TS 18090-1:2019 (E)
Contents Page

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

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SIST-TS CEN ISO/TS 18090-1:2019
CEN ISO/TS 18090-1:2019 (E)
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.
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SIST-TS CEN ISO/TS 18090-1:2019
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SIST-TS CEN ISO/TS 18090-1:2019
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
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SIST-TS CEN ISO/TS 18090-1:2019
ISO/TS 18090-1:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© 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. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved
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SIST-TS CEN ISO/TS 18090-1:2019
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 2015 – All rights reserved iii
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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
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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.
© ISO 2015 – All rights reserved v
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SIST-TS CEN ISO/TS 18090-1:2019
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 2015 – All rights reserved 1
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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
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
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
uni
uniformity of the air kerma distribution determined across a defined area
KK−
a, pulse, maxa, pulse, min
F =−1
uni
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
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3.6
pulse peak mean voltage
pulse, peak, mean

mean value of the sequence of X-ray tube voltages, U , measured during the radiation pulse peak time

peak
U = U
pulse, peak, mean i
peak
i=1
where
U is the i-th measured value;
n is the number of measurements of the X-ray tube voltage.
peak
3.7
pulse repetition frequency
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 radiation which never has a constant dose rate at a given

point in space for time intervals longer than 10 s
3.10
radiation pulse base duration
radiation pulse base width
pulse, base

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse deviates from zero

Note 1 to entry: The value zero of the equivalent trapezoidal pulse is equal to the baseline of the measured pulse.

3.11
radiation pulse duration
radiation pulse width
pulse

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse reaches 50 % of its maximum value
3.12
radiation pulse fall time
pulse, fall

interval of time between the last instants at which the instantaneous air kerma rate value of the

equivalent trapezoidal pulse reaches 80 % and 20 % of its maximum value
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3.13
radiation pulse air kerma rate
a,pulse

quotient of the air kerma per radiation pulse and the radiation pulse duration at a point in the photon

radiation field

Note 1 to entry: The air kerma per radiation pulse can be measured either by an integral measurement with an

ionization chamber or time resolved by a suitable instrument, both calibrated in terms of air kerma.

3.14
radiation pulse dose equivalent rate
a, pulse

quotient of the dose equivalent per radiation pulse and the radiation pulse duration at a point in the

photon radiation field

Note 1 to entry: The dose equivalent per radiation pulse can be measured either by an integral measurement with

an ionization chamber or time resolved by a suitable instrument, both calibrated in terms of the relevant quantity.

3.15
radiation pulse peak voltage ripple
pulse, peak, ripple

standard deviation of the sequence of X-ray tube voltages, U , measured during the radiation pulse peak

time
peeak
U = UU−
pulse, peak, ripple i pulse, peak, mean
n − 1
peak i
where
U is the i-th measured value of the X-ray tube voltage;
n is the number of measurements;
peak
U is the pulse peak mean voltage.
pulse, peak, mean
3.16
radiation pulse peak time
pulse peak time
pulse, peak

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse reaches 80 % of its maximum value

Note 1 to entry: The radiation pulse peak time is the interval of time between the end of the rise time and the

beginning of the fall time of the equivalent trapezoidal pulse.
3.17
radiation pulse plateau time
pulse, plateau

interval of time at which the instantaneous air kerma rate value of the equivalent trapezoidal pulse

reaches its maximum value
3.18
radiation pulse rise time
pulse, rise

interval of time between the first instants at which the instantaneous air kerma rate value of the

equivalent trapezoidal pulse reaches 20 % and 80 % of its maximum value
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3.19
trapezoidal pulse

unidirectional pulse having a constant gradient during increase from zero to its maximum value,

remains for a given time at this maximum value and having a constant gradient during its decrease

from the maximum value to zero
Note 1 to entry: See Figure 1.
pulse, plateau
100 %
80 %
pulse,peak
Amplitude
50 %
pulse
20 %
pulse,fall
pulse, rise
Baseline
0 %
pulse,base
Figure 1 — Equivalent trapezoidal radiation pulse with the relevant parameters
4 Characteristics of reference pulsed radiation
4.1 General

The characterization of the radiation pulse requires the time resolved measurement of the air kerma

rate and the tube high voltage during the pulse and the space resolved measurement of the air kerma of

the pulse. In general, these measurements cannot be done with one single instrument.

4.2 Time-dependent air kerma rate characteristics of the radiation pulse
4.2.1 Requirements

The pulse rise time plus the pulse fall time shall not exceed 0,6 times the pulse duration:

tt+≤ 06, ×t (1)
pulse, risepulse, fall pulse

The time resolved indicated values of the air kerma pulse rate, K , and the radiation pulse

a,pulse, ind
duration, t , shall be determined.
pulse
© ISO 2015 – All rights reserved 5
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4.2.2 Method of test

The time resolved indicated air kerma rate during the pulse, K , shall be measured with an

a,pulse, ind

instrument which provides a time resolution of better than 2 % of the radiation pulse duration, t . It

pulse

is important to synchronize the time scale with the time resolved measurements of the high voltage

(see 4.3.2). The measuring quantity shall be air kerma free-in-air, K . An absolute calibration of the

instrument is not required as only the relative response values are of interest. The response of the

instrument with respect to the air kerma rate
...

SLOVENSKI STANDARD
kSIST-TS FprCEN ISO/TS 18090-1:2019
01-julij-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: FprCEN ISO/TS 18090-1
ICS:
13.280 Varstvo pred sevanjem Radiation protection
kSIST-TS FprCEN ISO/TS 18090-1:2019 en,fr,de

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

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kSIST-TS FprCEN ISO/TS 18090-1:2019
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
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kSIST-TS FprCEN ISO/TS 18090-1:2019
ISO/TS 18090-1:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© 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. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved
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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

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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
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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.
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kSIST-TS FprCEN ISO/TS 18090-1:2019
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 2015 – All rights reserved 1
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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
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
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
uni
uniformity of the air kerma distribution determined across a defined area
KK−
a, pulse, maxa, pulse, min
F =−1
uni
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
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3.6
pulse peak mean voltage
pulse, peak, mean

mean value of the sequence of X-ray tube voltages, U , measured during the radiation pulse peak time

peak
U = U
pulse, peak, mean i
peak
i=1
where
U is the i-th measured value;
n is the number of measurements of the X-ray tube voltage.
peak
3.7
pulse repetition frequency
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 radiation which never has a constant dose rate at a given

point in space for time intervals longer than 10 s
3.10
radiation pulse base duration
radiation pulse base width
pulse, base

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse deviates from zero

Note 1 to entry: The value zero of the equivalent trapezoidal pulse is equal to the baseline of the measured pulse.

3.11
radiation pulse duration
radiation pulse width
pulse

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse reaches 50 % of its maximum value
3.12
radiation pulse fall time
pulse, fall

interval of time between the last instants at which the instantaneous air kerma rate value of the

equivalent trapezoidal pulse reaches 80 % and 20 % of its maximum value
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3.13
radiation pulse air kerma rate
a,pulse

quotient of the air kerma per radiation pulse and the radiation pulse duration at a point in the photon

radiation field

Note 1 to entry: The air kerma per radiation pulse can be measured either by an integral measurement with an

ionization chamber or time resolved by a suitable instrument, both calibrated in terms of air kerma.

3.14
radiation pulse dose equivalent rate
a, pulse

quotient of the dose equivalent per radiation pulse and the radiation pulse duration at a point in the

photon radiation field

Note 1 to entry: The dose equivalent per radiation pulse can be measured either by an integral measurement with

an ionization chamber or time resolved by a suitable instrument, both calibrated in terms of the relevant quantity.

3.15
radiation pulse peak voltage ripple
pulse, peak, ripple

standard deviation of the sequence of X-ray tube voltages, U , measured during the radiation pulse peak

time
peeak
U = UU−
pulse, peak, ripple i pulse, peak, mean
n − 1
peak i
where
U is the i-th measured value of the X-ray tube voltage;
n is the number of measurements;
peak
U is the pulse peak mean voltage.
pulse, peak, mean
3.16
radiation pulse peak time
pulse peak time
pulse, peak

interval of time between the first and last instants at which the instantaneous air kerma rate value of

the equivalent trapezoidal pulse reaches 80 % of its maximum value

Note 1 to entry: The radiation pulse peak time is the interval of time between the end of the rise time and the

beginning of the fall time of the equivalent trapezoidal pulse.
3.17
radiation pulse plateau time
pulse, plateau

interval of time at which the instantaneous air kerma rate value of the equivalent trapezoidal pulse

reaches its maximum value
3.18
radiation pulse rise time
pulse, rise

interval of time between the first instants at which the instantaneous air kerma rate value of the

equivalent trapezoidal pulse reaches 20 % and 80 % of its maximum value
4 © ISO 2015 – All rights reserved
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ISO/TS 18090-1:2015(E)
3.19
trapezoidal pulse

unidirectional pulse having a constant gradient during increase from zero to its maximum value,

remains for a given time at this maximum value and having a constant gradient during its decrease

from the maximum value to zero
Note 1 to entry: See Figure 1.
pulse, plateau
100 %
80 %
pulse,peak
Amplitude
50 %
pulse
20 %
pulse,fall
pulse, rise
Baseline
0 %
pulse,base
Figure 1 — Equivalent trapezoidal radiation pulse with the relevant parameters
4 Characteristics of reference pulsed radiation
4.1 General

The characterization of the radiation pulse requires the time resolved measurement of the air kerma

rate and the tube high voltage during the pulse and the space resolved measurement of the air kerma of

the pulse. In general, these measurements cannot be done with one single instrument.

4.2 Time-dependent air kerma rate characteristics of the radiation pulse
4.2.1 Requirements

The pulse rise time plus the pulse fall time shall not exceed 0,6 times the pulse duration:

tt+≤ 06, ×t (1)
pulse, risepulse, fall pulse

The time resolved indicated values of the air kerma pulse rate, K , and the radiation pulse

a,pulse, ind
duration, t , shall be determined.
pulse
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ISO/TS 18090-1:2015(E)
4.2.2 Method of test

The time resolved indicated air kerma rate during the pulse, K , shall be measured with an

a,pulse, ind

instrument which provides a time resolution of better than 2 % of the radiation pulse duration, t . It

pulse

is important to synchronize the time scale with the time resolved measurements of the high voltage

(see 4.3.2). The measuring quantity shall be air kerma free-in-air, K . An absolute calibration of the

instrument is not required as only the relative response values are of interest. The response of the

instrument with respect to the air kerma rate shall be constant within ±5 % in the required measuring

range (see 5.2). The sensitive area of the instrument shall be small, at maximum 1 cm × 1 cm. An example

is a semiconductor diode detector with a suitable preamplifier (see Annex A). The instrument shall be

positioned at the beam axis. An example of a schematic measurement result is shown in Figure 2.

The filtration of the X-ray tube shall be at least the inherent filtration according to ISO 4037-1:1996 or

IEC 61267:2005. Determine the sequence of indicated values of the air kerma rate during the radiation

pulse for any pulse duration and any high voltage intended to be used irrespective of the actual

filtration. From each of these sequences, the equivalent trapezoidal pulse shall be determined (see

Annex B) and then the pulse duration, t , the value of the pulse air kerma rate, K , and the

pulse
a,pulse, ind
durations t and t .
pulse, rise pulse, fall

In the energy range from the maximum photon energy according to the high voltage down to one third

of this energy, the air kerma response of the instrument as a function of photon energy should be as low

as possible, e.g. by using an energy compensation filter.
0,8
Diode-signal
Plateau
Rise
Fall
0,5
Baseline
0,2
-0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8
time in ms

NOTE The measured air kerma rate is transferred into an equivalent trapezoidal radiation pulse.

Figure 2 — Result of a time resolved measurement of the air kerma rate during the pulse with a

semiconductor diode and an oscilloscope
NOTE Determined parameters of the pulse for Figure 2:
t = 63 μs,
pulse, rise
t = 52 μs,
pulse, fall
t = 584 μs,
pulse
6 © ISO 2015 – All rights reserved
a, pulse, ind
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kSIST-TS FprCEN ISO/TS 18090-1:2019
ISO/TS 18090-1:2015(E)
t = 526 μs,
pulse, peak
t = 488 μs,
pulse, plateau
Area (Equivalent trapezoidal pulse) / Area (radiation pulse) = 1,0092.
4.2.3 Interpretation of the results
If for any given radiation pulse K , t t and t are determined and the sum of
pulse, pulse, rise pulse, fall
a,pulse, ind

rise time and fall time of the pulse does not exceed 0,6 times the pulse duration, then the requirements

of 4.2.1 are met.
4.3 Time-dependent high voltage characteristics of the radiation pulse
4.3.1 Requirement

The ripple of the high voltage during the pulse peak time, U , shall not exceed 0,07:

pulse, peak, ripple
peeak
U = UU− ≤ 00, 7 (2)
pulse, peak, ripple ∑ i pulse, peak, mean
n −1
peak
i=1
4.3.2 Method of test

A sequence of the high voltage values of the X-ray tube during the pulse shall be measured using a

high-frequency-compensated voltage divider. The instrument shall provide a time resolution of better

than 2 % of the pulse duration, t . It is important to synchronize the time scale with the time

pulse

resolved measurements of the air kerma rate (see 4.2.2), as the pulse peak time, t , is defined

pulse, peak

by the air kerma rate measurement. The radiation pulse can be generated by switching the high voltage

of the generator or by using a special X-ray tube which allows current switching by an additional grid.

Determine U and U for any high voltage intended to be used and any pulse
pulse, peak, mean pulse, peak, ripple

duration between the minimum pulse duration adjustable at the facility and 100 times this pulse duration.

4.3.3 Interpretation of the results

If for the given radiation pulse, the ripple of the high voltage during the pulse peak time, U ,

pulse, peak, ripple
does not exceed 0,07, then the requirement of 4.3.1 is met for that pulse.
4.4 Space dependent air kerma characteristics of the radiation pulse
4.4.1 Requirement on field uniformity across the beam area
The field uniformity, F , measured across the defined beam area and determined
...

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