ASTM_E_1654_-_94_2013.pdf

Designation:E165494(Reapproved 2013)Standard Guide forMeasuring Ionizing Radiation-Induced Spectral Changes inOptical Fibers and Cables for Use in Remote RamanFiberOptic Spectroscopy1This standard is issued under the fixed designation E1654;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers the method for measuring the realtime,in situ radiation-induced alterations to the Raman spectralsignal transmitted by a multimode,step index,silica opticalfiber.This guide specifically addresses steady-state ionizingradiation(that is,alpha,beta,gamma,protons,etc.)withappropriate changes in dosimetry,and shielding considerations,depending upon the irradiation source.1.2 The test procedure given in this guide is not intended totest the other optical and non-optical components of an opticalfiber-based Raman sensor system,but may be modified to testother components in a continuous irradiation environment.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E1614 Guide for Procedure for Measuring IonizingRadiation-Induced Attenuation in Silica-Based OpticalFibers and Cables for Use in Remote Fiber-Optic Spec-troscopy and Broadband Systems2.2 EIA Standards:32.2.1 Test or inspection requirements include the followingreferences:EIA-455-57 Optical Fiber End Preparation and ExaminationEIA-455-64Procedure for Measuring Radiation-InducedAttenuation in Optical Fibers and Cables2.3 Military Standards:4MIL-STD-2196-(SH)Glossary of Fiber Optic Terms3.Terminology3.1 DefinitionsRefer to the following documents for thedefinition of terms used in this guide:MIL-STD-2196-(SH)and Guide E1614.4.Significance and Use4.1 Ionizing environments will affect the performance ofoptical fibers/cables being used to transmit spectroscopicinformation from a remote location.Determination of the typeand magnitude of the spectral variations or interferencesproduced by the ionizing radiation in the fiber,or both,isnecessary for evaluating the performance of an optical fibersensor system.4.2 The results of the test can be utilized as a selectioncriteria for optical fibers used in optical fiber Raman spectro-scopic sensor systems.NOTE1The attenuation of optical fibers generally increases whenthey are exposed to ionizing radiation.This is due primarily to the trappingof radiolytic electrons and holes at defect sites in the optical materials,thatis,the formation of color centers.The depopulation of these color centersby thermal or optical(photobleaching)processes,or both,causesrecovery,usually resulting in a decrease in radiationinduced attenuation.Recovery of the attenuation after irradiation depends on many variables,including the temperature of the test sample,the composition of thesample,the spectrum and type of radiation employed,the total doseapplied to the test sample,the light level used to measure the attenuation,and the operating spectrum.Under some continuous conditions,recoveryis never complete.5.Apparatus5.1 The test schematic is shown in Fig.1.The following listidentifies the equipment necessary to accomplish this testprocedure.1This guide is under the jurisdiction of ASTM Committee E13 on MolecularSpectroscopy and Separation Science and is the direct responsibility of Subcom-mittee E13.09 on Fiber Optics,Waveguides,and Optical Sensors.Current edition approved Jan.1,2013.Published January 2013.Originallyapproved in 1994.Last previous version approved in 2004 as E1654 94(2004).DOI:10.1520/E1654-94R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Electronic Industries Alliance(EIA),2500 Wilson Blvd.,Arlington,VA 22201,http:/www.ecaus.org/eia.4Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/dodssp.daps.dla.mil.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Light SourceA laser source shall be used for theRaman analysis,and the wavelength must be chosen so that thefluorescent signals from the optical components(especially thespectral activator sample and optical fibers)are minimized,andso that the wavelength corresponds to the spectral sensitivity ofthe detection