ASTM E264-08(2013)
(Test Method)Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Nickel
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Nickel
SIGNIFICANCE AND USE
5.1 Refer to Guide E844 for the selection, irradiation, and quality control of neutron dosimeters.
5.2 Refer to Practice E261 for a general discussion of the determination of fast-neutron fluence rate with threshold detectors.
5.3 Pure nickel in the form of foil or wire is readily available, and easily handled.
5.4 58Co has a half-life of 70.86 days3 and emits a gamma ray with an energy of 0.8107593-MeV.4
5.5 Competing activities 65Ni(2.5172 h) and 57Ni(35.60 h) are formed by the reactions 64Ni(n,γ) 65Ni, and 58Ni(n,2n)57Ni, respectively.
5.6 A second 9.04 h isomer, 58mCo, is formed that decays to 70.86-day 58Co. Loss of 58Co and 58mCo by thermal-neutron burnout will occur in environments5,6 having thermal fluence rates of 3 × 1012 cm−2·s −1 and above. Burnout correction factors, R, are plotted as a function of time for several thermal fluxes in Fig. 1. Tabulated values for a continuous irradiation time are provided in Hogg, et al.6
5.7 Fig. 2 shows a plot of cross section7 versus energy for the fast-neutron reaction 58Ni(n,p) 58Co. This figure is for illustrative purposes only to indicate the range of response of the 58Ni(n,p) reaction. Refer to Guide E1018 for descriptions of recommended tabulated dosimetry cross sections.
FIG. 2 58Ni(n,p)58Co Cross SectionNote 1—The data is taken from the Evaluated Nuclear Data File, ENDF/B-VI, rather than the later ENDF/B-VII. This is in accordance with E1018, section 6.1, since the later ENDF/B-VII data files do not include covariance information. For more details see Section H of reference 8.8
SCOPE
1.1 This test method covers procedures for measuring reaction rates by the activation reaction 58Ni(n,p)58Co.Note 1—The burnup corrections were computed using effective burn-up cross sections of 1650 b for 58Co(n,γ) and 1.4E5 b for 58mCo(n,γ).
FIG. 1 R Correction Values as a Function of Irradiation Time and Neutron Flux
1.2 This activation reaction is useful for measuring neutrons with energies above approximately 2.1 MeV and for irradiation times up to about 200 days in the absence of high thermal neutron fluence rates (for longer irradiations, see Practice E261).
1.3 With suitable techniques fission-neutron fluence rates densities above 107 cm−2·s −1 can be determined.
1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E261.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E264 − 08 (Reapproved 2013)
Standard Test Method for
Measuring Fast-Neutron Reaction Rates by Radioactivation
of Nickel
This standard is issued under the fixed designation E264; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript 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 Defense.
1. Scope E261Practice for Determining Neutron Fluence, Fluence
Rate, and Spectra by Radioactivation Techniques
1.1 This test method covers procedures for measuring reac-
58 58 E844Guide for Sensor Set Design and Irradiation for
tion rates by the activation reaction Ni(n,p) Co.
Reactor Surveillance, E 706 (IIC)
1.2 Thisactivationreactionisusefulformeasuringneutrons
E944Guide for Application of Neutron Spectrum Adjust-
withenergiesaboveapproximately2.1MeVandforirradiation
ment Methods in Reactor Surveillance, E 706 (IIA)
times up to about 200 days in the absence of high thermal
E1005Test Method for Application and Analysis of Radio-
neutron fluence rates (for longer irradiations, see Practice
metric Monitors for Reactor Vessel Surveillance, E 706
E261).
(IIIA)
E1018Guide for Application of ASTM Evaluated Cross
1.3 With suitable techniques fission-neutron fluence rates
7 −2 −1
densities above 10 cm ·s can be determined. Section Data File, Matrix E706 (IIB)
1.4 Detailed procedures for other fast-neutron detectors are
3. Terminology
referenced in Practice E261.
3.1 Definitions:
1.5 The values stated in SI units are to be regarded as
3.1.1 Refer to Terminology E170.
standard. No other units of measurement are included in this
standard.
4. Summary of Test Method
1.6 This standard does not purport to address all of the
4.1 High-purity nickel is irradiated in a neutron field,
safety concerns, if any, associated with its use. It is the
58 58 58
thereby producing radioactive Co from the Ni(n,p) Co
responsibility of the user of this standard to establish appro-
activation reaction.
priate safety and health practices and determine the applica-
4.2 The gamma rays emitted by the radioactive decay of
bility of regulatory limitations prior to use.
Co are counted in accordance with Test Methods E181 and
2. Referenced Documents
the reaction rate, as defined by Practice E261, is calculated
from the decay rate and irradiation conditions.
2.1 ASTM Standards:
E170Terminology Relating to Radiation Measurements and
4.3 The neutron fluence rate above about 2.1 MeVcan then
Dosimetry
be calculated from the spectral-weighted neutron activation
E181Test Methods for Detector Calibration andAnalysis of
cross section as defined by Practice E261.
Radionuclides
5. Significance and Use
ThistestmethodisunderthejurisdictionofASTMCommitteeE10onNuclear
5.1 Refer to Guide E844 for the selection, irradiation, and
Technology and Applicationsand is the direct responsibility of Subcommittee
quality control of neutron dosimeters.
E10.05 on Nuclear Radiation Metrology.
Current edition approved Jan. 1, 2013. Published January 2013. Originally
5.2 Refer to Practice E261 for a general discussion of the
approved in 1965. Last edition approved in 2008 as E264–08. DOI: 10.1520/
determination of fast-neutron fluence rate with threshold de-
E0264-08R13.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or tectors.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.3 Pure nickel in the form of foil or wire is readily
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. available, and easily handled.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E264 − 08 (2013)
6. Apparatus
6.1 NaI (T1) or High Resolution Gamma-Ray Spectrometer.
Because of its high resolution, the germanium detector is
useful when contaminant activities are present (seeTest Meth-
ods E181 and E1005).
6.2 Precision Balance, able to achieve the required accu-
racy.
6.3 Digital Computer, useful for data analysis (optional).
7. Materials
7.1 The nickel metal must be low in contained cobalt to
prevent the production of Co by thermal-neutron capture.
NOTE 1—The burnup corrections were computed using effective
burn-up cross sections of 1650 b for Co(n,γ) and 1.4E5 b for Nickelproducedbythecarbonyl(Mond)processissufficiently
58m
Co(n,γ).
free of cobalt for even the most adverse conditions. Whenever
FIG. 1R Correction Values as a Function of Irradiation Time and
possible, all nickel should be tested for interfering impurities
Neutron Flux
by neutron activation.
7.2 Encapsulating Materials—Brass, stainless steel, copper,
aluminum, quartz, or vanadium have been used as primary
58 3
5.4 Co has a half-life of 70.86 days and emits a gamma
encapsulating materials. The container should be constructed
ray with an energy of 0.8107593-MeV.
in such a manner that it will not create significant flux
65 57
5.5 Competing activities Ni(2.5172 h) and Ni(35.60 h)
perturbation and that it may be opened easily, especially if the
64 65 58 57
areformedbythereactions Ni(n,γ) Ni,and Ni(n,2n) Ni,
capsule is to be opened remotely (see Guide E844).
respectively.
58m
8. Procedure
5.6 Asecond9.04hisomer, Co,isformedthatdecaysto
58 58 58m
70.86-day Co. Loss of Co and Co by thermal-neutron 8.1 Decide on the size and shape of nickel sample to be
5,6
burnout will occur in environments having thermal fluence
irradiated. This is influenced by the irradiation space and the
12 −2 −1 58
rates of 3×10 cm ·s and above. Burnout correction expected production of Co. Calculate the expected produc-
factors, R, are plotted as a function of time for several thermal
tion rate of Co from the activation equation described in
fluxes in Fig. 1. Tabulated values for a continuous irradiation Section 9, and adjust the sample size and irradiation time so
time are provided in Hogg, et al.
that the Co may be counted accurately.
5.7 Fig. 2 shows a plot of cross section versus energy for 8.2 Determine the level of thermal-neutron fluence rate by
58 58
the fast-neutron reaction Ni(n,p) Co. This figure is for
including a thermal-fluence rate monitor. Place the sample in a
illustrative purposes only to
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