ASTM E385-90

Standard Test Method for Oxygen Content Using a 14-MeV Neutron Activation and Direct-Counting Technique

General Information

• Status: Historical
• Publication Date: 31-Dec-1989
• Technical Committee: E10 - Nuclear Technology and Applications
• Drafting Committee: E10.05 - Nuclear Radiation Metrology

Standards Content (Sample)

ASTM E385 90 - 0759530 0077803 II -
AMERICAN SOCIETY FOR lESTlNG AND MATERIALS
Designation: E 385 - 90
1916 Race St Philadelphia, Pa 19103
Reprinfed from the Annual Book of ASM Standards. Copyright ASTM
#Tb
If not listed in the current combined index, will appear in the next edition.
Standard Test Method for
Oxygen Content Using a 149MeV Neutron Activation and
Direct-Counting Technique’
This standard is issued under the tixed designation E 385; 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 (c) indicates an editorial change since the last revision or reapproval.
1. Scope Code of Federal Regulations, Title 10, Part 20”
1.1 This test method covers the measurement of oxygen
concentration in almost any matrix by using a 14-MeV
3. Terminology
neutron activation and direct-counting technique. Essen-
3.1 DeJinitions (see also Terminology E 170):
tially, the same system may be used to determine oxygen
3.1.1 accelerator-a machine that ionizes a gas and elec-
concentrations ranging from over 50 % to about 10 yg/g, or
trically accelerates the ions onto a target. The accelerator
less, depending on the sample size and available 14-MeV
may be based on the Cockrofi-Walton, Van de Graaff, or
neutron fluence rates.
other design types (1). Compact sealed-tube, mixed deute-
NOTB I-The range of analysis may be extended by using higher
rium and tritium gas, Cockcroft-Walton neutron generators
neutron fluence rates, larger samples, and higher counting efficiency
are most commonly used for 14-MeV neutron activation
detectors.
analysis. However, “pumped” drift-tube accelerators that use
replaceable tritium-containing targets are also still in use. A
1.2 This test method may be used on either solid or liquid
review of operational characteristics, descriptions of acces-
samples, provided that they can be made to conform in size,
sory instrumentation, and applications of accelerators used
shape, and macroscopic density during irradiation and
as fast neutron generators is given in Ref (2).
counting to a standard sample of known oxygen content.
3.1.2 comparator standard-a reference standard of
Several variants of this method have been described in the
known oxygen content whose specific counting rate (counts
technical literature. A monograph is available which pro-
min-’ [mg of oxygen]-l) may be used to quantify the oxygen
vides a comprehensive description of the principles of
content of a sample irradiated and counted under the same
activation analysis using a neutron generator (1).2
conditions. Often, a comparator standard is selected to have
1.3 The values stated in either SI or inch-pound units are
a matrix composition, physical size, density and shape very
to be regarded separately as the standard. The values given in
similar to the corresponding parameters of the sample to be
parentheses are for information only.
analyzed. Comparative standards prepared in this way may
1.4 This standard does not purport to address all of the
be used directly as “monitors” (see 3.1.4) in order to avoid
safety problems associated with its use. It is the responsibility
the need for monitor-sample calibration plots, in those cases
ofthe user of this standard to establish appropriate safety and
where the usual monitor reference standard is physically or
health practices and determine the applicability of regulatory
chemically dissimilar to the samples to be analyzed.
limitations prior to use. Specific precautions are given in
3.1.3 ‘14~MeV neutron jluence rate-the area1 density of
Section 8.
neutrons passing through a sample, measured in terms of
neutrons cmm2 s-
‘, that is produced by the fusion reaction of
2. Referenced Documents
deuterium and tritium ions accelerated to energies of typi-
cally 150 to 200 keV in a small accelerator. Fluence rate is
2.1 ASTM Standards:
also commonly referred to as “flux density.” The total
E 170 Terminology Relating to Radiation Measurements
neutron fluence is the fluence rate integrated over time.
and Dosimetry3
3.1.3.1 Discussion-The 3H(d,n)4He reaction is used to
E 18 1 Method for Detector Calibration and Analysis of
produce approximately 14.7-MeV neutrons. This reaction
Radionuclides3
has a Q-value of i-17.586 MeV.
E 496 Method for Measuring Neutron Flux Density and
3.1.4 monitor-any type of detector or comparison refer-
Average Energy from 3H(d,n)4He Neutron Generators
ence material that can be used to produce a response
by Radioactivation Techniques3
proportional to the 14-MeV neutron fluence rate in the
2.2 US. Government Document:
irradiation position, or to the radionuclide decay events
recorded by the sample detector. A plastic pellet with a
known oxygen content is often used as a monitor reference
t This test method is under the juris
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