ASTM E2059-06
(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: E2059 – 06
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope ropy of the in-situ neutron field (4,5,7). It is not possible for
active detectors to provide such data because of in-situ
1.1 Nuclear Research Emulsions (NRE) have a long and
perturbations and finite-size effects (see Section 11).
illustrioushistoryofapplicationsinthephysicalsciences,earth
2 1.4 The existence of hydrogen as a major constituent of
sciences and biological sciences (1,2) . In the physical sci-
NRE affords neutron detection through neutron scattering on
ences, NRE experiments have led to many fundamental dis-
hydrogen, that is, the well known (n,p) reaction. NRE mea-
coveries in such diverse disciplines as nuclear physics, cosmic
surements in low power reactor environments have been
ray physics and high energy physics. In the applied physical
predominantly based on this (n,p) reaction. NRE have also
sciences, NRE have been used in neutron physics experiments
6 4 10 7
been used to measure the Li (n,t) He and the B(n,a) Li
in both fission and fusion reactor environments (3-6). Numer-
6 10
reactions by including Li and B in glass specks near the
ous NRE neutron experiments can be found in other applied
mid-plane of the NRE (8,9). Use of these two reactions does
disciplines, such as nuclear engineering, environmental moni-
not provide the general advantages of the (n,p) reaction for
toring and health physics. Given the breadth of NRE applica-
neutron dosimetry in low power reactor environments (see
tions, there exist many textbooks and handbooks that provide
Section4).Asaconsequence,thisstandardwillberestrictedto
considerable detail on the techniques used in the NRE method.
theuseofthe(n,p)reactionforneutrondosimetryinlowpower
As a consequence, this practice will be restricted to the
reactor environments.
application of the NRE method for neutron measurements in
1.5 Limitations—The NRE method possesses three major
reactorphysicsandnuclearengineeringwithparticularempha-
limitations for applicability in low power reactor environ-
sis on neutron dosimetry in benchmark fields (see Matrix
ments.
E706).
1.5.1 Gamma-Ray Sensitivity—Gamma-rays create a sig-
1.2 NRE are passive detectors and provide time integrated
nificantlimitationforNREmeasurements.Aboveagamma-ray
reaction rates. As a consequence, NRE provide fluence mea-
exposure of approximately 3R, NRE can become fogged by
surements without the need for time-dependent corrections,
gamma-ray induced electron events. At this level of gamma-
such as arise with radiometric (RM) dosimeters (see Test
ray exposure, neutron induced proton-recoil tracks can no
Method E1005). NRE provide permanent records, so that
longer be accurately measured. As a consequence, NRE
optical microscopy observations can be carried out anytime
experiments are limited to low power environments such as
after exposure. If necessary, NRE measurements can be re-
found in critical assemblies and benchmark fields. Moreover,
peated at any time to examine questionable data or to obtain
applications are only possible in environments where the
refined results.
buildup of radioactivity, for example, fission products, is
1.3 Since NRE measurements are conducted with optical
limited.
microscopes, high spatial resolution is afforded for fine struc-
1.5.2 Low Energy Limit—In the measurement of track
ture experiments. The attribute of high spatial resolution can
length for proton recoil events, track length decreases as
also be used to determine information on the angular anisot-
proton-recoil energy decreases. Proton-recoil track length be-
low approximately 3µ in NRE can not be adequately measured
1
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
with optical microscopy techniques. As proton-recoil track
Technology and Applications , and is the direct responsibility of Subcommittee
length decreases below approximately 3µ, it becomes very
E10.05 on Nuclear Radiation Metrology.
difficult to measure track length accurately. This 3µ track
Current edition approved Jan. 1, 2006. Published February 2006. Originally
approved in 2000. Last previous edition approved in 2005 as E2059-05. DOI:
length limit corresponds to a low energy limit of applicability
10.1520/E2059-06.
in the range of approximately 0.3 to 0.4 MeV for neutron
2
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
induced proton-recoil measurements in NRE.
the
...
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