ASTM E2059-06(2010)
(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
SIGNIFICANCE AND USE
Integral Mode Dosimetry—As shown in 3.2, two different integral relationships can be established using proton-recoil emulsion data. These two integral reactions can be obtained with roughly an order of magnitude reduction in scanning effort. Consequently this integral mode is an important complementary alternative to the customary differential mode of NRE spectrometry. The integral mode can be applied over extended spatial regions, for example, perhaps up to as many as ten in-situ locations can be covered for the same scanning effort that is expended for a single differential measurement. Hence the integral mode is especially advantageous for dosimetry applications which require extensive spatial mapping, such as exist in Light Water Reactor-Pressure Vessel (LWR-PV) benchmark fields (see Test Method E1005). In low power benchmark fields, NRE can be used as integral dosimeters in a manner similar to RM, solid state track recorders (SSTR) and helium accumulation monitors (HAFM) neutron dosimeters (see Test Methods E854 and E910). In addition to spatial mapping advantages of these other dosimetry methods, NRE offer fine spatial resolution and can therefore be used in-situ for fine structure measurements. In integral mode scanning, both absolute reaction rates, that is I(ET) and J(Emin), are determined simultaneously. Separate software codes need to be used to permit operation of a computer based interactive system in the integral mode (see Section 9). It should be noted that the integrals I(ET) and J(Emin) possess different units, namely proton-recoil tracks/MeV per hydrogen atom and proton-recoil tracks per hydrogen atom, respectively.
SCOPE
1.1 Nuclear Research Emulsions (NRE) have a long and illustrious history of applications in the physical sciences, earth sciences and biological sciences (1,2) . 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 (3-6). 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 E706).
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 E1005). 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 (4,5,7). It is not possible for active detectors to provide such data because of in-situ perturbations and finite-size effects (see Section 11).
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,α) 7Li reactions by including...
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Designation: E2059 − 06(Reapproved 2010)
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
sciences and biological sciences (1,2) . In the physical
1.4 The existence of hydrogen as a major constituent of
sciences, NRE experiments have led to many fundamental NRE affords neutron detection through neutron scattering on
discoveries in such diverse disciplines as nuclear physics,
hydrogen, that is, the well known (n,p) reaction. NRE mea-
cosmic ray physics and high energy physics. In the applied surements in low power reactor environments have been
physical sciences, NRE have been used in neutron physics
predominantly based on this (n,p) reaction. NRE have also
6 4 10 7
experiments in both fission and fusion reactor environments been used to measure the Li (n,t) He and the B(n,α) Li
6 10
(3-6). Numerous NRE neutron experiments can be found in
reactions by including Li and B in glass specks near the
otherapplieddisciplines,suchasnuclearengineering,environ- mid-plane of the NRE (8,9). Use of these two reactions does
mental monitoring and health physics. Given the breadth of
not provide the general advantages of the (n,p) reaction for
NRE applications, there exist many textbooks and handbooks neutron dosimetry in low power reactor environments (see
that provide considerable detail on the techniques used in the
Section4).Asaconsequence,thisstandardwillberestrictedto
NREmethod.Asaconsequence,thispracticewillberestricted theuseofthe(n,p)reactionforneutrondosimetryinlowpower
to the application of the NRE method for neutron measure-
reactor environments.
ments in reactor physics and nuclear engineering with particu-
1.5 Limitations—The NRE method possesses three major
lar emphasis on neutron dosimetry in benchmark fields (see
limitations for applicability in low power reactor environ-
Matrix E706).
ments.
1.2 NRE are passive detectors and provide time integrated
1.5.1 Gamma-Ray Sensitivity—Gamma-rays create a sig-
reaction rates. As a consequence, NRE provide fluence mea-
nificantlimitationforNREmeasurements.Aboveagamma-ray
surements without the need for time-dependent corrections,
exposure of approximately 3R, NRE can become fogged by
such as arise with radiometric (RM) dosimeters (see Test
gamma-ray induced electron events. At this level of gamma-
Method E1005). NRE provide permanent records, so that
ray exposure, neutron induced proton-recoil tracks can no
optical microscopy observations can be carried out anytime
longer be accurately measured. As a consequence, NRE
after exposure. If necessary, NRE measurements can be re-
experiments are limited to low power environments such as
peated at any time to examine questionable data or to obtain
found in critical assemblies and benchmark fields. Moreover,
refined results.
applications are only possible in environments where the
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.
Current edition approved Oct. 1, 2010. Published November 2010. Originally
difficult to measure track length accurately. This 3µ track
approved in 2000. Last previous edition approved in 2006 as E2059-06. DOI:
length limit corresponds to a low energy limit of applicability
10.1520/E2059-10.
2 in the range of approximately 0.3 to 0.4 MeV for neutron
The boldface numbers in parentheses refer to the list of references at the end of
induced proton-recoil measureme
...
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