1、Optics and photonics Lasers and laser- related equipment Laser-induced molecular contamination testing PD ISO/TR 20811:2017 BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017 Optics and photonics Lasers and laser-related equipment Laser- induced molecular con
2、tamination testing Qualification des composants optiques laser pour les applications spatiales TECHNICAL REPORT ISO/TR 20811 Reference number ISO/TR 20811:2017(E) First edition 2017-08 National foreword This Published Document is the UK implementation of ISO/TR 20811:2017. The UK participation in it
3、s preparation was entrusted to Technical Committee CPW/172, Optics and Photonics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its
4、correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017 ISBN 978 0 580 91058 6 ICS 31.260 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy an
5、d Strategy Committee on 30 September 2017. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD ISO/TR 20811:2017 ISO 2017 Optics and photonics Lasers and laser-related equipment Laser- induced molecular contamination testing Qualification des composants optiques l
6、aser pour les applications spatiales TECHNICAL REPORT ISO/TR 20811 Reference number ISO/TR 20811:2017(E) First edition 2017-08 PD ISO/TR 20811:2017 ISO/TR 20811:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in Switzerland All rights reserved. Unless otherwis
7、e 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 belo
8、w or ISOs 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 copyrightiso.org www.iso.org PD ISO/TR 20811:2017 ISO/TR 20811:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTE
9、CTED DOCUMENT ISO 2017, 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 prio
10、r written permission. Permission can be requested from either ISO at the address below or ISOs 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 copyrightiso.org www.iso.orgISO/
11、TR 20811:2017(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Symbols and abbreviated terms . 2 5 Test method . 2 5.1 Test setup . 2 5.1.1 Vacuum chamber . 2 5.1.2 Laser source and optical beam line . 3 5.2 Setup for data acquisition 3 5.2.1 Beam prof
12、ile monitoring . 3 5.2.2 Measurement of pulse energy and determination of transmission . 3 5.2.3 Laser-induced fluorescence monitoring . 4 5.3 Test preparation . 4 5.3.1 Bakeout 4 5.3.2 Pretreatment of optical samples 4 5.3.3 Blank test 4 5.4 LIMC test . 5 5.4.1 Test parameters 5 5.4.2 Individual st
13、eps for LIMC test . 5 5.5 Evaluation of test results 6 Bibliography .10 ISO 2017 All rights reserved iii Contents Page PD ISO/TR 20811:2017 ISO/TR 20811:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies
14、). 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 no
15、n-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 descr
16、ibed 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 draw
17、n 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 t
18、he ISO list of patent declarations received (see www .iso .org/ patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expr
19、essions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html. This document was prepared by Technical Committee ISO/TC 172, Opt
20、ics and photonics, Subcommittee SC 9, Electro-optical systems.iv ISO 2017 All rights reserved PD ISO/TR 20811:2017 ISO/TR 20811:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing
21、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 liaiso
22、n 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 Direc
23、tives, 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
24、 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 dec
25、larations received (see www .iso .org/ patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to confor
26、mity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html. This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcom
27、mittee SC 9, Electro-optical systems.iv ISO 2017 All rights reserved ISO/TR 20811:2017(E) Introduction Laser technique is becoming increasingly important for space applications. Complex laser systems are used both for Earth observation and for planetary exploration. For long-term operations, optical
28、 components have to satisfy stringent requirements concerning precision and reliability. Before being used in space, all optical components have to be tested extensively. For standardized determination of laser damage threshold, ISO 21254 (all parts) should be applied. For characterization of optics
29、 for space applications, corresponding tests should be performed under vacuum conditions. In addition to laser damage issues, laser-induced molecular contamination (LIMC) should be taken into account. LIMC denotes the interaction of laser radiation, especially in case of high fluences and short wave
30、lengths with volatile molecules and the resulting formation of deposits on optical components. LIMC proved to be particularly critical, if the laser system is operated under vacuum conditions and could considerably reduce the functionality of the whole laser system. Molecular contamination is mainly
31、 caused by organic materials and silicones, e.g. glues, adhesives, insulating material or circuit boards due to stronger outgassing rates compared to inorganic materials. The outgassing can be reduced but not totally prevented by selection of suitable materials and preconditioning, e.g. bake-out at
32、elevated temperature well above the planned operating temperature. The outgassing behaviour of materials is generally characterized by these parameters: collected volatile condensable material (CVCM), total mass loss (TML), recovered mass loss (RML), volatile condensable material (VCM) and water vap
33、our regained (WVR). Definitions and corresponding measuring specifications for these quantities can be found in ECSS-Standard Q-ST-70-02C, ASTM-E595-07 and ASTM-E1559. This document outlines the test procedure for investigations of laser-induced molecular contamination in order to compare the growth
34、 of laser-induced depositions on optical surfaces for different molecular contamination materials. ISO 2017 All rights reserved v PD ISO/TR 20811:2017 Optics and photonics Lasers and laser-related equipment Laser-induced molecular contamination testing 1 Scope This document describes the setup, test
35、 procedure and analysis of measured data for investigation of laser-induced molecular contamination (LIMC) for space and vacuum applications. LIMC is the formation of depositions on optical surfaces due to interaction of intense light radiation with outgassing molecules especially from organic mater
36、ials. It is a phenomenon of molecular contamination and it is distinguished from particle contamination, which can occur during manufacturing, assembly, integration or test of the optical components. Formation of laser-induced depositions can lead to deterioration of the performance of an optical sy
37、stem. Phase distortion, scattering and absorption can be increased by LIMC. LIMC is of particular relevance, if a laser system is operated in vacuum at short wavelength and short pulse duration. In such a case, even small partial pressure of contamination material in the range of 10 5hPa could have
38、strong negative impact on optical performance. It was also shown that the laser-induced damage threshold could be reduced by a factor of 10 and more if laser-induced depositions are involved. Laser-induced molecular contamination and laser-induced damage are both phenomena, for which the interaction
39、 of laser radiation with optical surfaces plays a major role, in case of LIMC with additional molecular contamination. Therefore, this document is treated in relation to ISO 21254 (all parts) which specifies the test methods for the determination of laser-induced damage thresholds. This method was d
40、erived to evaluate qualitatively, whether the material under investigation causes deposits on optical surfaces in a low-pressure environment in the presence of high-energy nanosecond pulsed laser irradiation at a wavelength of 355 nm. Due to the nature of photochemical surface reactions, this result
41、 cannot be directly transferred to scenarios where the properties of the irradiation are altered (especially wavelength, repetition rate, pulse duration, etc.). Due to the non-linear growth of the laser- induced contamination and its detection methods, this technique does not provide quantitative me
42、ans to evaluate the deposit and, therefore, it should be seen as a means to compare materials relatively with respect to their laser-induced contamination behaviour. Furthermore, it is out of the scope of this method to select representative quantities of contamination materials representative with
43、respect to the material partial pressure present in the vicinity of the optical surface in a real laser system. This is carefully derived with other methods and is a mandatory parameter to be fixed before applying this method. 2 Normative references The following documents are referred to in the tex
44、t in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11145, Optics and photonics Lasers and lase
45、r-related equipment Vocabulary and symbols ISO 21254 (all parts), Lasers and laser-related equipment Test methods for laser-induced damage threshold 3 T erms an d definiti ons For the purposes of this document, the terms and definitions given in ISO 11145 and ISO 21254 (all parts) and the following
46、apply. TECHNICAL REPORT ISO/TR 20811:2017(E) ISO 2017 All rights reserved 1 PD ISO/TR 20811:2017 Optics and photonics Lasers and laser-related equipment Laser-induced molecular contamination testing 1 Scope This document describes the setup, test procedure and analysis of measured data for investiga
47、tion of laser-induced molecular contamination (LIMC) for space and vacuum applications. LIMC is the formation of depositions on optical surfaces due to interaction of intense light radiation with outgassing molecules especially from organic materials. It is a phenomenon of molecular contamination an
48、d it is distinguished from particle contamination, which can occur during manufacturing, assembly, integration or test of the optical components. Formation of laser-induced depositions can lead to deterioration of the performance of an optical system. Phase distortion, scattering and absorption can
49、be increased by LIMC. LIMC is of particular relevance, if a laser system is operated in vacuum at short wavelength and short pulse duration. In such a case, even small partial pressure of contamination material in the range of 10 5hPa could have strong negative impact on optical performance. It was also shown that the laser-induced damage threshold could be reduced by a factor of 10 and more if laser-induced depositions are involved. Laser-induced molecular contamination and laser-induced damage are both phenomena, for
