ASTM E2059-00a
(Practice)Standard Practice for Application and Analysis of Nuclear Research Emulsions for Fast Neutron Dosimetry
Standard Practice for Application and Analysis of Nuclear Research Emulsions for Fast Neutron Dosimetry
SCOPE
1.1 Nuclear Research Emulsions (NRE) have a long and illustrious history of applications in the physical sciences, earth sciences and biological sciences (,). In the physical sciences, NRE experiments have led to many fundamental discoveries in such diverse disciplines as nuclear physics, cosmic ray physics and high energy physics. In the applied physical sciences, NRE have been used in neutron physics experiments in both fission and fusion reactor environments (). Numerous NRE neutron experiments can be found in other applied disciplines, such as nuclear engineering, environmental monitoring and health physics. Given the breadth of NRE applications, there exist many textbooks and handbooks that provide considerable detail on the techniques used in the NRE method. As a consequence, this practice will be restricted to the application of the NRE method for neutron measurements in reactor physics and nuclear engineering with particular emphasis on neutron dosimetry in benchmark fields (see Matrix E 706).
1.2 NRE are passive detectors and provide time integrated reaction rates. As a consequence, NRE provide fluence measurements without the need for time-dependent corrections, such as arise with radiometric (RM) dosimeters (see Test Method E 1005). NRE provide permanent records, so that optical microscopy observations can be carried out anytime after exposure. If necessary, NRE measurements can be repeated at any time to examine questionable data or to obtain refined results.
1.3 Since NRE measurements are conducted with optical microscopes, high spatial resolution is afforded for fine structure experiments. The attribute of high spatial resolution can also be used to determine information on the angular anisotropy of the in-situ neutron field (,,). It is not possible for active detectors to provide such data because of in-situ perturbations and finite-size effects (see Section ).
1.4 The existence of hydrogen as a major constituent of NRE affords neutron detection through neutron scattering on hydrogen, that is, the well known (n,p) reaction. NRE measurements in low power reactor environments have been predominantly based on this (n,p) reaction. NRE have also been used to measure the 6Li ( n,t) 4He and the 10B (n,) 7Li reactions by including 6Li and 10B in glass specks near the mid-plane of the NRE (,). Use of these two reactions does not provide the general advantages of the (n,p) reaction for neutron dosimetry in low power reactor environments (see Section ). As a consequence, this standard will be restricted to the use of the (n,p) reaction for neutron dosimetry in low power reactor environments.
1.5 Limitations The NRE method possesses three major limitations for applicability in low power reactor environments.
1.5.1 Gamma-Ray SensitivityGamma-rays create a significant limitation for NRE measurements. Above a gamma-ray exposure of approximately 3R, NRE can become fogged by gamma-ray induced electron events. At this level of gamma-ray exposure, neutron induced proton-recoil tracks can no longer be accurately measured. As a consequence, NRE experiments are limited to low power environments such as found in critical assemblies and benchmark fields. Moreover, applications are only possible in environments where the buildup of radioactivity, for example, fission products, is limited.
1.5.2 Low Energy Limit In the measurement of track length for proton recoil events, track length decreases as proton-recoil energy decreases. Proton-recoil track length below approximately 3 in NRE can not be adequately measured with optical microscopy techniques. As proton-recoil track length decreases below approximately 3, it becomes very difficult to measure track length accurately. This 3 track length limit corresponds to a low energy limit of applicability in the range of approximately 0.3 to 0.4 MeV for neutron induced proton-recoil measurements in NRE.
1.5.3 Track Density LimitThe ability to measure proton recoil ...
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Designation: E 2059 – 00a
Standard Practice for
Application and Analysis of Nuclear Research Emulsions for
1
Fast Neutron Dosimetry
This standard is issued under the fixed designation E 2059; 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.
1. Scope hydrogen, that is, the well known (n,p) reaction. NRE mea-
surements in low power reactor environments have been
1.1 Nuclear Research Emulsions (NRE) have a long and
predominantly based on this (n,p) reaction. NRE have also
illustrioushistoryofapplicationsinthephysicalsciences,earth
6 4 10 7
2 been used to measure the Li (n,t) He and the B(n,a) Li
sciences and biological sciences (1,2) . In the physical sci-
6 10
reactions by including Li and B in glass specks near the
ences, NRE experiments have led to many fundamental dis-
mid-plane of the NRE (8,9). Use of these two reactions does
coveries in such diverse disciplines as nuclear physics, cosmic
not provide the general advantages of the (n,p) reaction for
ray physics and high energy physics. In the applied physical
neutron dosimetry in low power reactor environments (see
sciences, NRE have been used in neutron physics experiments
Section 4).As a consequence, this standard will be restricted to
in both fission and fusion reactor environments (3-6). Numer-
theuseofthe(n,p)reactionforneutrondosimetryinlowpower
ous NRE neutron experiments can be found in other applied
reactor environments.
disciplines, such as nuclear engineering, environmental moni-
1.5 Limitations—The NRE method possesses three major
toring and health physics. Given the breadth of NRE applica-
limitations for applicability in low power reactor environ-
tions, there exist many textbooks and handbooks that provide
ments.
considerable detail on the techniques used in the NRE method.
1.5.1 Gamma-Ray Sensitivity—Gamma-rays create a sig-
As a consequence, this practice will be restricted to the
nificantlimitationforNREmeasurements.Aboveagamma-ray
application of the NRE method for neutron measurements in
exposure of approximately 3R, NRE can become fogged by
reactor physics and nuclear engineering with particular empha-
gamma-ray induced electron events. At this level of gamma-
sis on neutron dosimetry in benchmark fields (see Matrix
ray exposure, neutron induced proton-recoil tracks can no
E 706).
longer be accurately measured. As a consequence, NRE
1.2 NRE are passive detectors and provide time integrated
experiments are limited to low power environments such as
reaction rates. As a consequence, NRE provide fluence mea-
found in critical assemblies and benchmark fields. Moreover,
surements without the need for time-dependent corrections,
applications are only possible in environments where the
such as arise with radiometric (RM) dosimeters (see Test
buildup of radioactivity, for example, fission products, is
Method E 1005). NRE provide permanent records, so that
limited.
optical microscopy observations can be carried out anytime
1.5.2 Low Energy Limit—In the measurement of track
after exposure. If necessary, NRE measurements can be re-
length for proton recoil events, track length decreases as
peated at any time to examine questionable data or to obtain
proton-recoil energy decreases. Proton-recoil track length be-
refined results.
low approximately 3µ in NRE can not be adequately measured
1.3 Since NRE measurements are conducted with optical
with optical microscopy techniques. As proton-recoil track
microscopes, high spatial resolution is afforded for fine struc-
length decreases below approximately 3µ, it becomes very
ture experiments. The attribute of high spatial resolution can
difficult to measure track length accurately. This 3µ track
also be used to determine information on the angular anisot-
length limit corresponds to a low energy limit of applicability
ropy of the in-situ neutron field (4,5,7). It is not possible for
in the range of approximately 0.3 to 0.4 MeV for neutron
active detectors to provide such data because of in-situ
induced proton-recoil measurements in NRE.
perturbations and finite-size effects (see Section 11).
1.5.3 Track Density Limit—The ability to measure proton
1.4 The existence of hydrogen as a major constituent of
recoil track length with optical microscopy techniques depends
NRE affords neutron detection through neutron scattering on
on track density. Above a certain track density, a maze or
labyrinth of tracks is created, which precludes the use of
1
This specification is under the jurisdiction of ASTM Committee E10 on
optical microscopy techniques. For manual scanning, this
Nuclear Technology and Applications, and is t
...
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