1、Designation: E720 11E720 16Standard Guide forSelection and Use of Neutron Sensors for DeterminingNeutron Spectra Employed in Radiation-Hardness Testing ofElectronics1This standard is issued under the fixed designation E720; the number immediately following the designation indicates the year oforigin
2、al 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.This standard has been approved for use by agencies of the U.S. Department of
3、 Defense.1. Scope1.1 This guide covers the selection and use of neutron-activation detector materials to be employed in neutron spectraadjustment techniques used for radiation-hardness testing of electronic semiconductor devices. Sensors are described that havebeen used at many radiation hardness-te
4、sting facilities, and comments are offered in table footnotes concerning the appropriatenessof each reaction as judged by its cross-section accuracy, ease of use as a sensor, and by past successful application. This guide alsodiscusses the fluence-uniformity, neutron self-shielding, and fluence-depr
5、ession corrections that need to be considered in choosingthe sensor thickness, the sensor covers, and the sensor locations. These considerations are relevant for the determination of neutronspectra from assemblies such as TRIGA- and Godiva-type reactors and from Californium irradiators. This guide m
6、ay also beapplicable to other broad energy distribution sources up to 20 MeV.NOTE 1For definitions on terminology used in this guide, see Terminology E170.1.2 This guide also covers the measurement of the gamma-ray or beta-ray emission rates from the activation foils and othersensors as well as the
7、calculation of the absolute specific activities of these foils. The principal measurement technique ishigh-resolution gamma-ray spectrometry.The activities are used in the determination of the energy-fluence spectrum of the neutronsource. See Guide E721.1.3 Details of measurement and analysis are co
8、vered as follows:1.3.1 Corrections involved in measuring the sensor activities include those for finite sensor size and thickness in the calibrationof the gamma-ray detector, for pulse-height analyzer deadtime and pulse-pileup losses, and for background radioactivity.1.3.2 The primary method for det
9、ector calibration that uses secondary standard gamma-ray emitting sources is considered in thisguide and in GeneralTest Methods E181. In addition, an alternative method in which the sensors are activated in the knownspectrum of a benchmark neutron field is discussed in Guide E1018.1.3.3 A data analy
10、sis method is presented which accounts for the following: detector efficiency; background subtraction;irradiation, waiting, and counting times; fission yields and gamma-ray branching ratios; and self-absorption of gamma rays andneutrons in the sensors.1.4 The values stated in SI units are to be rega
11、rded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and deter
12、mine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 General considerations of neutron-activation detectors discussed in Practice E261, Test Method E262, and Guides E721 andE844 are applicable to this guide. Background information for applying this guide are given
13、in these and other relevant standardsas follows:1 This guide is under the jurisdiction of ASTM Committee E10 on Nuclear Technology and Applicationsand is the direct responsibility of Subcommittee E10.07 onRadiation Dosimetry for Radiation Effects on Materials and Devices.Current edition approved Jun
14、e 1, 2011Dec. 1, 2016. Published July 2011February 2017. Originally approved in 1980. Last previous edition approved in 20082011 asE720 08.E720 11. DOI: 10.1520/E0720-11.10.1520/E0720-16.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication
15、of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be consider
16、ed the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 ASTM Standards:2E170 Terminology Relating to Radiation Measurements and DosimetryE181 Test Methods for Detector Calibration and Analysis of RadionuclidesE261
17、 Practice for Determining Neutron Fluence, Fluence Rate, and Spectra by Radioactivation TechniquesE262 Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by RadioactivationTechniquesE263 Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivatio
18、n of IronE264 Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of NickelE265 Test Method for Measuring Reaction Rates and Fast-Neutron Fluences by Radioactivation of Sulfur-32E266 Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of AluminumE393 Test Me
19、thod for Measuring Reaction Rates by Analysis of Barium-140 From Fission DosimetersE496 Test Method for Measuring Neutron Fluence andAverage Energy from 3H(d,n)4He Neutron Generators by RadioactivationTechniquesE704 Test Method for Measuring Reaction Rates by Radioactivation of Uranium-238E705 Test
20、Method for Measuring Reaction Rates by Radioactivation of Neptunium-237E721 Guide for Determining Neutron Energy Spectra from Neutron Sensors for Radiation-Hardness Testing of ElectronicsE844 Guide for Sensor Set Design and Irradiation for Reactor Surveillance, E 706 (IIC)E944 Guide for Application
21、of Neutron Spectrum Adjustment Methods in Reactor Surveillance, E 706 (IIA)E1018 Guide for Application of ASTM Evaluated Cross Section Data File, Matrix E706 (IIB)E1297 Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Niobium3. Significance and Use3.1 Because of the wide v
22、ariety of materials being used in neutron-activation measurements, this guide is presented with theobjective of bringing improved uniformity to the specific field of interest here: hardness testing of electronics primarily in criticalassembly reactor environments.NOTE 2Some of the techniques discuss
23、ed are useful for 14-MeV dosimetry. See Test Method E496 for activation detector materials suitable for14-MeV neutron effects testing.NOTE 3The materials recommended in this guide are suitable for 252Cf or other weak source effects testing provided the fluence is sufficient togenerate countable acti
24、vities.3.2 This guide is organized into two overlapping subjects; the criteria used for sensor selection, and the procedures used toensure the proper determination of activities for determination of neutron spectra. SeeTerminology E170 and GeneralTest MethodsE181. Determination of neutron spectra wi
25、th activation sensor data is discussed in Guides E721 and E944.4. Foil Sets4.1 Reactions Considered:4.1.1 Neutron-induced reactions appropriate for this guide are listed in Table 1. The table includes most of the reactions usedin this field. Those not marked with an asterisk are recommended because
26、of their demonstrated compatibility with other reactionsused in spectrum adjustment determinations. This compatibility is primarily based on experience with the ENDF/B-VIENDF/B-VI.1 (1, 2),)3, and IRDF-90 IRDFF n1.05 (3) cross-sections. These recommendations may change modestly as revisions are made
27、in the ENDF/B and IRDF dosimetry cross sections. Other reactions may be useful in particular circumstances with appropriatecare. It is important that the user take full account of both the footnotes attached to each reaction and the discussions in the bodyof the text about individual reactions when
28、implementing the foil-activation technique.4.1.2 The four paired columns under the labels fast burst (13) and “TRIGA(14) Type” list the energy ranges within which 95 %of the response occurs for these two representative spectra. These limits are just a guide because the response often varies widelywi
29、thin each range. The response limits for an idealized fission spectrum with no 1/E tail can be much different (shifted towardhigher energy) for resonance reactions. For example, in a Watt fission spectrum the 197Au(n,)198Au has a 95 % response between5.0 102 and 2.7 MeV. The recommended foil mass co
30、lumn gives values that are designed to minimize self-absorption,self-shielding, and other corrections, provided the foils are 1.27 cm in diameter. The Et 0 fission foils, 235U and 239Pu, havesimilar cross-section shapes. However, the 235U foil is preferred since it is less expensive and is much less
31、 of a health hazard than239Pu. In addition, when measuring soft (TRIGA) spectra, the 235U foil is useful in determining the correction for the 235Uimpurity in the 238U foil (which is readily available with about 400 ppm or less 235U impurity).4.1.3 Although sulfur is listed and is used widely as a m
32、onitor foil, it is the only recommended sensor requiring beta particledetection and, therefore, requires a different calibration and counting technique. The 58Ni(n,p)58Co reaction has about the samethreshold energy and, therefore, can be used instead of the 32S(n,p)32P if it acquires sufficient acti
33、vity. Many facilities use sulfur2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The boldface numbers in par
34、entheses refer to the list of references at the end of this guide.E720 162TABLE 1 Activation FoilsReactionFast BurstA TRIGA TypeAEB , (keV)GammaEmissionProbabilityBFast FissionYield,C % T1/2B RecommendedFoil Mass, gD FootnotesEL, MeV EH, MeV EL, MeV EH, MeV197Au(n,)198Au 4.00 6 7.20 4 3.80 6 9.20 6
35、411.8025 95.54 2.6944 days 0.06 E,F,G197Au(n,)198Au 4.00 6 7.20 4 3.80 6 9.20 6 411.80205 95.62 2.6943 days 0.06 E,F,G59Co(n,)60Co 7.60 6 4.50 4 6.90 7 1.43 4 1173.2 99.85 5.2711 years 0.06 E,G59Co(n,)60Co 7.60 6 4.50 4 6.90 7 1.43 4 1173.228 99.85 5.2711 years 0.06 E,G1332.5 99.981332.492 99.9826*5
36、8Fe(n,)59Fe 1.00 6 2.10 + 0 5.25 7 1.00 2 1099.245 56.59 44.495 days 0.15 E,H*58Fe(n,)59Fe 1.00 6 2.10 + 0 5.25 7 1.00 2 1099.245 56.51 44.494 days 0.15 E,H1291.59 43.211291.590 43.2355Mn(n,)56Mn 5.25 7 6.60 1 4.75 7 1.10 3 846.76 98.85 2.57878 h 0.05 E,F55Mn(n,)56Mn 5.25 7 6.60 1 4.75 7 1.10 3 846.
37、7638 98.85 2.57878 h 0.05 E,F1810.726 26.9*63Cu(n,)64Cu 1.15 6 2.30 + 0 5.25 7 9.60 3 1345.77 0.4743 12.700 h 0.15 E*63Cu(n,)64Cu 1.15 6 2.30 + 0 5.25 7 9.60 3 1345.77 0.4748 12.7004 h 0.15 E23Na(n,)24Na 6.30 7 2.00 + 0 5.25 7 3.00 3 1368.626 99.993 14.9574 h 0.10 E,I,J23Na(n,)24Na 6.30 7 2.00 + 0 5
38、.25 7 3.00 3 1368.630 99.9934 14.4958 h 0.10 E,I,J2754.1 99.8722754.049 99.86245Sc(n,)46Sc 4.25 7 1.00 + 0 4.00 7 4.75 4 889.27 99.983 83.788 days 0.05 E45Sc(n,)46Sc 4.25 7 1.00 + 0 4.00 7 4.75 4 889.271 99.98374 83.787 days 0.05 E1120.537 99.9861120.537 99.97235U(n,f)140La 9.20 2 4.70 + 0 6.30 4 3.
39、80 + 0 1596.2 95.4 6.105 40.28 h 0.30 E,K,L235U(n,f)140La 9.20 2 4.70 + 0 6.30 4 3.80 + 0 1596.203 95.40 5.9599 1.67858 days 0.30 E,K,L235U(n,f)95Zr 9.20 2 4.70 + 0 6.30 4 3.80 + 0 724.2 44.27 6.363 64.03 days 0.60 E,L235U(n,f)95Zr 9.20 2 4.70 + 0 6.30 4 3.80 + 0 724.192 44.27 6.3488 64.032 days 0.6
40、0 E,L756.7 54.4756.725 54.438239Pu(n,f)140La 1.43 1 4.80 + 0 8.80 4 4.30 + 0 1596.2 95.4 5.326 40.28 h 1.00 E,K,L239Pu(n,f)140La 1.43 1 4.80 + 0 8.80 4 4.30 + 0 1596.203 95.40 5.3244 1.67858 days 1.00 E,K,L239Pu(n,f)95Zr 1.43 1 4.80 + 0 8.80 4 4.30 + 0 724.2 44.1 4.685 64.02 days 0.60 E,L239Pu(n,f)9
41、5Zr 1.43 1 4.80 + 0 8.80 4 4.30 + 0 724.192 44.27 4.6825 64.032 days 0.60 E,L756.7 54.4756.725 54.3893Nb(n,n)93mNb 8.40 1 5.70 + 0 1.00 + 0 5.50 + 0 16.5-19.6 11.0 16.12 years M93Nb(n,n)93mNb 8.40 1 5.70 + 0 1.00 + 0 5.50 + 0 30.77 0.000591 16.12 years M103Rh(n,n)103mRh 5.50 1 5.70 + 0 6.90 1 5.70 +
42、 0 39.8 0.068 56.1 min M103Rh(n,n)103mRh 5.50 1 5.70 + 0 6.90 1 5.70 + 0 39.755 0.068 56.114 min M237Np(n,f)140La 5.75 1 5.60 + 0 6.60 1 5.50 + 0 1596.2 95.4 5.489 40.28 h 0.60 E,K,L,N237Np(n,f)140La 5.75 1 5.60 + 0 6.60 1 5.50 + 0 1596.203 95.40 5.74440 1.67858 days 0.60 E,K,L,N237Np(n,f)95Zr 5.75
43、1 5.60 + 0 6.60 1 5.50 + 0 724.2 44.1 5.699 64.02 days 0.60 E,L237Np(n,f)95Zr 5.75 1 5.60 + 0 6.60 1 5.50 + 0 724.192 44.27 5.61470 64.032 days 0.60 E,L756.7 54.4756.725 54.38*115In(n,n)115mIn 1.00 + 0 6.00 + 0 1.20 + 0 5.80 + 0 336.2 45.9 4.49 h 0.12*115In(n,n)115mIn 1.00 + 0 6.00 + 0 1.20 + 0 5.80
44、 + 0 336.241 45.8 4.486 h 0.12238U(n,f)140La 1.50 + 0 6.90 + 0 1.50 + 0 6.60 + 0 1596.2 95.4 5.948 40.28 h 1.00 E,K,L,O238U(n,f)140La 1.50 + 0 6.90 + 0 1.50 + 0 6.60 + 0 1596.203 95.40 5.9718 40.28 h 1.00 E,K,L,O238U(n,f)95Zr 1.50 + 0 6.90 + 0 1.50 + 0 6.60 + 0 724.2 44.1 5.105 64.02 days 1.00 E,L23
45、8U(n,f)95Zr 1.50 + 0 6.90 + 0 1.50 + 0 6.60 + 0 724.192 44.27 5.1883 64.032 days 1.00 E,L756.7 54.4756.725 54.38232Th(n,f)140Ba 1.50 + 0 7.40 + 0 1.50 + 0 7.10 + 0 537.3 24.4 7.704 12.753 days 1.00 E,K,P232Th(n,f)140Ba 1.50 + 0 7.40 + 0 1.50 + 0 7.10 + 0 537.303 24.39 7.7121 12.753 days 1.00 E,K,P23
46、2Th(n,f)95Zr 1.50 + 0 7.40 + 0 1.50 + 0 7.10 + 0 724.2 44.1 5.374 64.02 days 1.00 E,L232Th(n,f)95Zr 1.50 + 0 7.40 + 0 1.50 + 0 7.10 + 0 724.192 44.27 5.5230 64.032 days 1.00 E,L756.7 54.4756.725 54.3854Fe(n,p)54Mn 2.30 + 0 7.70 + 0 2.30 + 0 7.40 + 0 834.838 99.9746 312.13 days 0.15 E54Fe(n,p)54Mn 2.
47、30 + 0 7.70 + 0 2.30 + 0 7.40 + 0 834.848 99.9752 312.19 days 0.15 E58Ni(n,p)58Co 2.00 + 0 7.60 + 0 2.00 + 0 7.30 + 0 810.7 99.45 70.83 days 0.30 E58Ni(n,p)58Co 2.00 + 0 7.60 + 0 2.00 + 0 7.30 + 0 810.7602 99.44 70.85 days 0.30 E47Ti(n,p)47Sc 1.90 + 0 7.60 + 0 1.90 + 0 7.30 + 0 159.4 68.3 3.35 days
48、0.15 E,Q,R47Ti(n,p)47Sc 1.90 + 0 7.60 + 0 1.90 + 0 7.30 + 0 159.373 68.1 3.3485 days 0.15 E,Q,R32S(n,p)32P 2.40 + 0 7.50 + 0 2.30 + 0 7.30 + 0 1710.6 100. (beta) 14.284 days . S32S(n,p)32P 2.40 + 0 7.50 + 0 2.30 + 0 7.30 + 0 1710.66 100. (beta) 14.284 days . S64Zn(n,p)64Cu 2.60 + 0 7.70 + 0 2.60 + 0
49、 7.40 + 0 1345.7 0.4743 12.700 h 0.30 E64Zn(n,p)64Cu 2.60 + 0 7.70 + 0 2.60 + 0 7.40 + 0 1345.77 0.4748 12.7004 h 0.30 E27Al(n,p)27Mg 3.50 + 0 9.40 + 0 3.40 + 0 9.20 + 0 843.8 71.8 9.46 min 0.30 E27Al(n,p)27Mg 3.50 + 0 9.40 + 0 3.40 + 0 9.20 + 0 843.76 71.800 9.458 min 0.30 E1014.4 28.046Ti(n,p)46Sc 3.80 + 0 9.60 + 0 3.70 + 0 9.20 + 0 889.3 99.983 83.788 days 0.15 E,QE720 163as a routine monitor
