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The accuracy of the prompt γ-ray analysis is known to degrade for the samples containing neutron-scattering materials, such as hydrogen, depending on its content. Recently, we discovered that the density of the scattering materials also affects the accuracy. In this paper, we developed a correction method for the effect of the sample densities. The developed correction method is straightforward and applicable to samples with unknown densities. The simulation and experiments verified the performance of the correction method. The results confirmed that the correction method could reduce the uncertainty due to sample density from 47% to approximately 1%. [ABSTRACT FROM AUTHOR]

A high-accuracy analytical method is broadly required to obtain reliable research results. Thus, prompt γ-ray analysis (PGA), one of the most accurate non-destructive analytical methods, has been employed in various fields. However, the measurement accuracy of PGA is also known to degrade in hydrogenous samples. The degradation is caused by variation in the measurement sensitivity (counts per milligram) following the change in neutron energy due to scattering with hydrogen nucleus. Number of scatterings is well known to depend on the hydrogen content in a sample. However, considering multiple scatterings, hydrogen density, which has not been taken into account as yet, may also lead to the accuracy degradation. Here, we show the effect of the hydrogen density in PGA by evaluating the measurement sensitivity of samples with the same hydrogen content and different densities. We find that the measurement sensitivity varies by more than 30% depending on the hydrogen density even at the same hydrogen content. The variation is a particularly serious problem for PGA requiring a few percent accuracy in most cases. Additionally, although the variation is apparently observed in hydrogenous samples, the similar phenomenon can occur in other nuclides with a large scattering cross section; it may affect nuclear cross-section measurements using neutrons in such fields as astrophysics and nuclear energy. [ABSTRACT FROM AUTHOR]

211At is artificially produced for medical purposes. To prevent severe loss of short-lived 211At, a rapid method analyzing both the radioactivity and all chemical forms was required for related fundamental researches. We propose a new method by means of an α-scintillation-camera system comprising of thin-layer chromatography and a high-sensitive CCD camera. The performance of the system was experimentally verified: low-radioactivity 211At of 56–672 Bq was measured in a short-time of 1000 s and all chemical forms of 211At were evaluated. The results reveal that the method enables us to analyze two features of 211At with significantly short-time. [ABSTRACT FROM AUTHOR]

• Shape effects for samples are critical for analysis using neutron-capture reactions. • Three non-destructive imaging methods estimated shape effects of sealed samples. • The energy-resolved neutron imaging could evaluate the non-uniformity of the samples quantitatively. • The energy-resolved neutron imaging is effective for improving the accuracy of analysis using neutron capture reactions. To determine neutron capture cross-sections and elemental/isotopic compositions accurately via neutron capture reactions, shape effects caused by uniformity of samples must be considered. However, the estimation of shape effects is difficult to verify in some cases: sealed samples and valuable objects. In this study, the effects on sealed radioactive samples were estimated experimentally. A capability of energy-resolved neutron imaging enabled us to confirm significant localization of the sealed 129I sample non-destructively. It is revealed that shape effects should be corrected for obtaining accurate experimental results. Consequently, we conclude that energy-resolved neutron imaging will be effective to improve analytical accuracy. [ABSTRACT FROM AUTHOR]

The neutron capture cross sections of 129 I and 127 I were measured from the thermal to the keV energy regions with the NaI(Tl) spectrometer of the Accurate Neutron-Nucleus Reaction Measurement Instrument beamline in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The neutron capture yield was determined by means of the total energy detection principle with the pulse-height weighting technique. The present cross section results for 127 I were normalized using the saturated resonance method with a thick-enough 197 Au sample and provide good overall agreement with JENDL-5 from thermal to about 500 keV. A resonance analysis with the REFIT code was performed and the resonance parameters for both 129 I and 127 I below 100 eV are presented in this work. In the case of 129 I, four large resonances of 127 I were employed for the cross section normalization since it was included as an impurity. The present results for 129 I are the first experimental data to cover a wide neutron region from 10 meV to about 30 keV. In the neutron region between thermal and 20 eV, the present results display a different energy dependence than that in the JENDL-5 and JEFF-3.3 and much similar to that in ENDF/B-VIII.0. Notwithstanding, good agreement was found at the thermal region between the present measurement of 31.0 ± 1.4 b and both evaluated and most experimental data. [ABSTRACT FROM AUTHOR]

The neutron total and capture cross sections of 181Ta were measured at the Accurate Neutron-Nucleus Research Measurement Instrument of the Materials and Life Science Experimental Facility in the Japan Proton Accelerator Research Complex to improve the accuracy of the current resonance parameters. The total cross section was determined from the transmission measurement in the energy range from 0.2 to 150 eV. The capture cross section was derived from the capture yield using the pulse height weighting technique in the energy range from thermal to 150 eV. The thermal neutron capture cross section was measured as $$21.3 \pm 0.3(stat) \pm 0.6(sys)$$ 21.3 ± 0.3 (stat) ± 0.6 (sys) b. The obtained transmission and capture cross section were simultaneously fitted using the resonance analysis code REFIT, and the resonance parameters for resonances below 150 eV were evaluated. The present resonance parameters were compared to reported measurements. [ABSTRACT FROM AUTHOR]

We determined the free + adsorbed water and the bound water in aggregates and cement pastes using conventional gravimetric analysis and prompt γ-ray analysis, respectively, to evaluate the total water content in concretes. The contents of free + adsorbed water and bound water in some geochemical references were also determined to confirm the accuracy in the present work. The content of each water in aggregates collected from different quarries and cement pastes with different water-to-cement ratios were analyzed. The total water content in young concrete was evaluated on the basis of the analytical values. [ABSTRACT FROM AUTHOR]

The energy-resolved neutron imaging system, RADEN, has been installed at the pulsed neutron source in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. In addition to conventional neutron radiography and tomography, RADEN, the world's first imaging beam-line at a pulsed neutron source, provides three main options for new, quantitative neutron imaging techniques: Bragg-edge imaging to visualize the spatial distribution of crystallographic information, resonance absorption imaging for elemental composition and temperature information, and polarized neutron imaging for magnetic field information. This paper describes the results of characterization studies of the neutronic performance and installed devices at RADEN and shows the results of several demonstration studies for pulsed neutron imaging. [ABSTRACT FROM AUTHOR]

Abstract Neutron resonance absorption imaging, being used to visualize a spatial distribution of elements and/or temperature within a sample, is one of the important applications of an intense short-pulse neutron source. Two-dimensional time-analyzer neutron detectors are indispensable to perform neutron energy dependent imaging by means of the time-of-flight technique. Some state-of-the-art time-analyzer neutron detectors have been developed for thermal or cold neutrons. However the detection efficiencies of such neutron detectors are not sufficient for neutron resonance absorption imaging which utilizes neutrons in the energy region from eV to keV. The 2012 model lithium-6 time-analyzer neutron detector (LiTA12) system, based on a lithium glass scintillator and multi-anode photomultiplier tube, has the highest neutron efficiency among the detectors for pulsed neutron imaging together with the flexibility to tune the efficiency by changing the thickness of the lithium glass. The authors estimated performances of the detector at resonance neutron energies finding that 0.7 mm width line pairs made by 3 μm thick gold could be resolved at 4.9 eV and the maximum count rate of 8 Mcps was achieved at 1 keV. [ABSTRACT FROM AUTHOR]