ASTM E264-92(1996)

Designation: E 264 – 92 (Reapproved 1996)
Standard Test Method for
Measuring Fast-Neutron Reaction Rates by Radioactivation
of Nickel
This standard is issued under the fixed designation E 264; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Terminology
1.1 This test method covers procedures for measuring reac- 3.1 Definitions:
58 58
tion rates by the activation reaction Ni(n,p) Co. 3.1.1 Refer to Terminology E 170.
1.2 This activation reaction is useful for measuring neutrons
4. Summary of Test Method
with energies above approximately 2.1 MeV and for irradiation
4.1 High-purity nickel is irradiated in a neutron field,
times up to about 200 days in the absence of high thermal
58 58 58
neutron fluence rates (for longer irradiations, see Practice thereby producing radioactive Co from the Ni(n,p) Co
E 261). activation reaction.
4.2 The gamma rays emitted by the radioactive decay of
1.3 With suitable techniques fission-neutron fluence rates
7 −2 −1 58
densities above 10 cm ·s can be determined. Co are counted in accordance with Test Methods E 181 and
the reaction rate, as defined by Practice E 261, is calculated
1.4 Detailed procedures for other fast-neutron detectors are
referenced in Practice E 261. from the decay rate and irradiation conditions.
4.3 The neutron fluence rate above about 2.1 MeV can then
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the be calculated from the spectral-weighted neutron activation
cross section as defined by Practice E 261.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 Refer to Guide E 844 for the selection, irradiation, and
2. Referenced Documents
quality control of neutron dosimeters.
5.2 Refer to Practice E 261 for a general discussion of the
2.1 ASTM Standards:
E 170 Terminology Relating to Radiation Measurements determination of fast-neutron fluence rate with threshold de-
tectors.
and Dosimetry
E 181 Test Methods for Detector Calibration and Analysis 5.3 Pure nickel in the form of foil or wire is readily
available, and easily handled.
of Radionuclides
E 261 Practice for Determining Neutron Fluence Rate, Flu- 5.4 Co has a half-life of 70.82 days and emits a gamma
ray with an energy of 0.8108-MeV.
ence, and Spectra by Radioactivation Techniques
65 57
5.5 Competing activities Ni(2.52 h) and Ni(36.1 h) are
E 844 Guide for Sensor Set Design and Irradiation for
64 65 58 57
Reactor Surveillance, E 706(IIC) formed by the reactions Ni(n,g) Ni, and Ni(n,2n) Ni,
respectively.
E 944 Guide for Application of Neutron Spectrum Adjust-
58m
ment Methods in Reactor Surveillance, (IIA) 5.6 A second 9.15–h isomer, Co, is formed that decays to
58 58 58m
70.82-day Co. Loss of Co and Co by thermal-neutron
E 1005 Test Method for Application and Analysis of Radio-
metric Monitors for Reactor Vessel Surveillance, burnout will occur in environments having thermal fluence
12 −2 −1 58 59
rates of 3 3 10 cm ·s and above. The Co(n,g) Co and
E 706(IIIA)
E 1018 Guide for Application of ASTM Evaluated Cross 58mCo(n,g) Co cross sections have been measured at 1650
2 4
and 1.4 3 10 barns, respectively. Burnout correction factors,
Section Data File, Matrix E 706(IIB)
R, are plotted as a function of time for several thermal fluxes in
Fig. 1.
This test method is under the jurisdiction of ASTM Committee E-10 on Nuclear
Technology and Applications and is the direct responsibility of Subcommittee
“Nuclear Data Sheets for A 5 58,” National Nuclear Data Center, Vol 42, 1984,
E10.05 on Nuclear Radiation Metrology.
p. 457.
Current edition approved Oct. 15, 1992. Published March 1993. Originally
Hogg, C. H., Weber, L. D., and Yates, E. C., “Isomers and the Effects on Fast
published as E 264 – 65 T. Last edition E 264 – 87.
Flux Measurements Using Nickel,” Atomic Energy Commission R and D Report
Annual Book of ASTM Standards, Vol 12.02.
IDO-16744, 1962.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 264
FIG. 1 R Correction Values as a Function of Irradiation Time and
Neutron Flux
5.7 Fig. 2 shows a plot of cross section versus energy for the
58 58 5
fast-neutron reaction Ni(n,p) Co. This figure is for illus-
58 58
FIG. 2 Ni(n,p) Co Cross Section
trative purposes only to indicate the range of response of the
58Ni(n,p) reaction. Refer to Guide E 1018 for descriptions of
recommended tabulated dosimetry cross sections.
8.4 Irradiate the sample for the predetermined time period.
Record the power level and any changes in power during the
6. Apparatus
irradiation, the time at the beginning and end of the irradiation
6.1 NaI (T1) or High Resolution Gamma-Ray Spectrometer.
period,
...