ASTM_E_1855_-_15.pdf

Designation:E185515Standard Test Method forUse of 2N2222A Silicon Bipolar Transistors as NeutronSpectrum Sensors and Displacement Damage Monitors1This standard is issued under the fixed designation E1855;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 test method covers the use of 2N2222A siliconbipolar transistors as dosimetry sensors in the determination ofneutron energy spectra and as 1 Mev(Si)equivalent displace-ment damage fluence monitors.1.2 The neutron displacement in silicon can serve as aneutron spectrum sensor in the range 0.1 to 2.0 MeV whenfission foils are not available.It has been applied in the fluencerange between 2 1012n/cm2to 1 1014n/cm2and should beuseful up to 1 1015n/cm2.This test method details theacquisition and use of 1 Mev(Si)equivalent fluence informa-tion for the partial determination of the neutron spectra byusing 2N2222A transistors.1.3 This sensor yields a direct measurement of the silicon 1Mev equivalent fluence by the transfer technique.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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 requirements prior to use.2.Referenced Documents2.1 The ASTM standards E170,E261,and E265 provide abackground for understanding how sensors are used in radia-tion measurements and general dosimetry.The rest of thestandards referenced in the list discuss the choice of sensors,spectrum determinations with sensor data,and the prediction ofneutron displacement damage in some semiconductor devices,particularly silicon.2.2 ASTM Standards:2E170 Terminology Relating to Radiation Measurements andDosimetryE261 Practice for Determining Neutron Fluence,FluenceRate,and Spectra by Radioactivation TechniquesE265 Test Method for Measuring Reaction Rates and Fast-Neutron Fluences by Radioactivation of Sulfur-32E720 Guide for Selection and Use of Neutron Sensors forDetermining Neutron Spectra Employed in Radiation-Hardness Testing of ElectronicsE721 Guide for Determining Neutron Energy Spectra fromNeutron Sensors for Radiation-Hardness Testing of Elec-tronicsE722 Practice for Characterizing Neutron Fluence Spectra inTerms of an Equivalent Monoenergetic Neutron Fluencefor Radiation-Hardness Testing of ElectronicsE844 Guide for Sensor Set Design and Irradiation forReactor Surveillance,E 706(IIC)E944 Guide for Application of Neutron Spectrum Adjust-ment Methods in Reactor Surveillance,E 706(IIA)E1854 Practice for Ensuring Test Consistency in Neutron-Induced Displacement Damage of Electronic PartsE2005 Guide for Benchmark Testing of Reactor Dosimetryin Standard and Reference Neutron FieldsE2450 Practice for Application of CaF2(Mn)Thermolumi-nescence Dosimeters in Mixed Neutron-Photon Environ-ments3.Terminology3.1 Symbols:1=the silicon 1 Mev equivalent fluence(see Practice E722).hFE=ic/ibwhere icis the collector current and ibis the basecurrent,in a common emitter circuit.4.Summary of Test Method4.1 Gain degradation of 2N2222Asilicon bipolar transistorsmeasured in a test(simulation)environment is compared witha measured reference neutron environment.The 1rin the1This test method is under the jurisdiction of ASTM Committee E10 on NuclearTechnology and Applicationsand is the direct responsibility of SubcommitteeE10.07 on Radiation Dosimetry for Radiation Effects on Materials and Devices.Current edition approved Oct.1,2015.Published November 2015.Originallyapproved in 1996.Last previous edition approved in 2010 as E1855 10.DOI:10.1520/E1855-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 reference environment is derived from the known referencespectrum and is used to determine a measured 1tin the testenvironment(1,2)3.The subscripts r and t refer to the referenceand test environments respectively.4.2 The measured 1tmay be used as a sensor response ina spectrum adjustment code combined with reaction foilactivities to determine the spectrum(3,4).4.3 Spectra compatible with the responses of many sensorsmay be used to calculate a more reliable measure of thedisplacement damage.5.Significance and Use5.1 The neutron test spectrum must be known in order to usea measured device response to predict the device performancein an operational environment(E1854