ASTM E2059-05
(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 High-Energy LimitsAs a consequence of finite-size limita...
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Designation: E 2059 – 05
Standard Practice for
Application and Analysis of Nuclear Research Emulsions for
1
Fast Neutron Dosimetry
This standard is issued under the fixed designation E2059; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope active detectors to provide such data because of in-situ
perturbations and finite-size effects (see Section 11).
1.1 Nuclear Research Emulsions (NRE) have a long and
1.4 The existence of hydrogen as a major constituent of
illustrioushistoryofapplicationsinthephysicalsciences,earth
2 NRE affords neutron detection through neutron scattering on
sciences and biological sciences (1,2) . In the physical sci-
hydrogen, that is, the well known (n,p) reaction. NRE mea-
ences, NRE experiments have led to many fundamental dis-
surements in low power reactor environments have been
coveries in such diverse disciplines as nuclear physics, cosmic
predominantly based on this (n,p) reaction. NRE have also
ray physics and high energy physics. In the applied physical
6 4 10 7
been used to measure the Li (n,t) He and the B(n,a) Li
sciences, NRE have been used in neutron physics experiments
6 10
reactions by including Li and B in glass specks near the
in both fission and fusion reactor environments (3-6). Numer-
mid-plane of the NRE (8,9). Use of these two reactions does
ous NRE neutron experiments can be found in other applied
not provide the general advantages of the (n,p) reaction for
disciplines, such as nuclear engineering, environmental moni-
neutron dosimetry in low power reactor environments (see
toring and health physics. Given the breadth of NRE applica-
Section4).Asaconsequence,thisstandardwillberestrictedto
tions, there exist many textbooks and handbooks that provide
theuseofthe(n,p)reactionforneutrondosimetryinlowpower
considerable detail on the techniques used in the NRE method.
reactor environments.
As a consequence, this practice will be restricted to the
1.5 Limitations—The NRE method possesses three major
application of the NRE method for neutron measurements in
limitations for applicability in low power reactor environ-
reactorphysicsandnuclearengineeringwithparticularempha-
ments.
sis on neutron dosimetry in benchmark fields (see Matrix
1.5.1 Gamma-Ray Sensitivity—Gamma-rays create a sig-
E706).
nificantlimitationforNREmeasurements.Aboveagamma-ray
1.2 NRE are passive detectors and provide time integrated
exposure of approximately 3R, NRE can become fogged by
reaction rates. As a consequence, NRE provide fluence mea-
gamma-ray induced electron events. At this level of gamma-
surements without the need for time-dependent corrections,
ray exposure, neutron induced proton-recoil tracks can no
such as arise with radiometric (RM) dosimeters (see Test
longer be accurately measured. As a consequence, NRE
Method E1005). NRE provide permanent records, so that
experiments are limited to low power environments such as
optical microscopy observations can be carried out anytime
found in critical assemblies and benchmark fields. Moreover,
after exposure. If necessary, NRE measurements can be re-
applications are only possible in environments where the
peated at any time to examine questionable data or to obtain
buildup of radioactivity, for example, fission products, is
refined results.
limited.
1.3 Since NRE measurements are conducted with optical
1.5.2 Low Energy Limit—In the measurement of track
microscopes, high spatial resolution is afforded for fine struc-
length for proton recoil events, track length decreases as
ture experiments. The attribute of high spatial resolution can
proton-recoil energy decreases. Proton-recoil track length be-
also be used to determine information on the angular anisot-
low approximately 3µ in NRE can not be adequately measured
ropy of the in-situ neutron field (4,5,7). It is not possible for
with optical microscopy techniques. As proton-recoil track
length decreases below approximately 3µ, it becomes very
1
This specification is under the jurisdiction of ASTM Committee E10 on
difficult to measure track length accurately. This 3µ track
Nuclear Technology and Applications , and is the direct responsibility of Subcom-
length limit corresponds to a low energy limit of applicability
mittee E10.05 on Nuclear Radiation Metrology.
in the range of approximately 0.3 to 0.4 MeV for neutron
Current edition approved Jan. 1, 2005. Published February 2005. Originally
induced proton-recoil measurements in NRE.
approved in 2000. Last previous edition approved in 2000 as E2059-00a.
2
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the text.
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