This study uses gamma-ray spectrometry and geochemical analysis to provide a first assessment of natural radioactivity and radiogenic heat production (RHP) in the Rundvagshetta region, East Antarctica. Direct gamma-ray spectrometry was used to measure U-238, Th-232, and K-40 in samples of gneisses, granulites and migmatites. The findings reveal that felsic rocks, particularly gneisses, are enriched in U, Th, and K, generating the highest RHP (similar to 2.29 mu W/m(3)), whereas mafic rocks, such as granulites, exhibit lower RHP (similar to 0.05 mu W/m(3)). The calculated RHP values from Rundvagshetta are moderate and fall within the range of the global continental crustal average. Despite the limited number of samples, the results show clear large variability, indicating that heat-producing elements are unevenly distributed even within the small outcrop. This study, therefore, emphasises the significant role of lithological and mineralogical variability in regulating regional heat production and the necessity of an expanded RHP database in East Antarctica by performing detailed radiometric analyses.

Previously we reported a simple algorithmic method of spectral determination method (SDM), which is based on the first principle that a gamma-ray spectrum obtained for a sample is a linear superposition of individual spectra of the radioactive nuclides included in the sample and demonstrated that the method is valid for gamma-ray determination. Here, we apply it to the spectra obtained by liquid scintillation counter (LSC). In LSC measurements quenching is generally observed, and we at first developed its correction method to standard spectra. The SDM code reported in the previous investigation is used to analyze the LSC spectra. Based on the analyses done by using the measured spectra, we concluded that the SDM method is valid in the LSC spectra similarly to the gamma-ray spectra studied in the previous investigation.

So far, we have developed the innovative radioactivity quantification technique of spectral determination method (SDM) and applied it to spectra measured with Ge, NaI detectors and liquid scintillation counter (LSC). In the present study we extended the SDM to apply to a unified spectrum composed of LSC and Ge detector, and the number of nuclides has been increased from 8 or 9 to 40. We selected 40 radionuclides from possible radionuclides included in nuclear debris and radioactive wastes in the environment which were produced by the nuclear accident in Fukushima in 2011. We prepared LSC and Ge standard spectra by direct measurements and simulation calculations utilizing the Geant 4.10.3 Monte Carlo simulation tool kit. The derived LSC and Ge spectra for each nuclide were unified to a single spectrum and the 40 sets of them were completed as a unified database. We studied the determination accuracy of the present analysis by examining a composed spectrum made of 40 radionuclides with equal intensities. The SDM result shows that the relative determination uncertainties of 35 nuclides are below 20%. It is also indicated that by removing 3 interfering nuclides the determination accuracy of the other 37 nuclides could be improved.

We investigated potential germline-specific radiosensitive biomarkers in the testes of large Japanese field mice (Apodemus speciosus) exposed to low-dose-rate (LDR) radiation after the Fukushima accident. Fukushima wild mice testes were analysed via RNA-sequencing to identify genes differentially expressed in the breeding and non-breeding seasons when compared to controls. Results revealed significant changes during the breeding season, with Lsp1 showing a considerable upregulation, while Ptprk and Tspear exhibited significant reductions. Conversely, in the non-breeding season, Fmo2 and Fmo2 (highly similar) were significantly upregulated in radiation-exposed Fukushima mice. qPCR analysis results were consistent with transcriptome sequencing, detecting Lsp1 and Ptprk regulation in the testes of Fukushima mice. While differences in gene expression were observed, these do not imply any causal association between the identified biomarkers and chronic LDR exposure, as other factors such as the environment and developmental age may contribute. This study provides valuable insights into the reproductive biology is affected by environmental radiation and highlights the value of assessing the effects of chronic LDR radiation exposure on testicular health in wild mice.

We propose a simple algorithmic method of spectral determination method (SDM) for gamma-ray determination, which is based on the first principle that a gamma-ray spectrum obtained for a sample is a linear superposition of individual spectra of the radioactive nuclides included in the sample. The SDM treats the whole spectrum including peaks and a continuum background due to Compton scattering and does not need the peak analysis, which has been most conventionally used so far. The SDM was demonstrated by using two separate detector setups with a NaI detector or a Ge detector. The first experiment utilized six mixed standard sources. The determination accuracy of the SDM has turned out to be reasonable as compared with that of the peak analysis. In the next experiment for standard samples of JSAC0731 and JSAC0785, both Ge and NaI results show that the deviation of the SDM results from the certified values is within reasonable uncertainties for C-137 and Cs-134. The present study demonstrates that the SDM is a reliable gamma-ray determination method with a simple procedure.

Gamma-gamma coincidence measurement utilized in gamma-ray spectroscopy experiments is well known to be effective for the improvement of signal-to-noise ratio in a gamma-ray spectrum. We study its applicability to the determination of long-lived radioactive nuclides in environmental samples. The gamma-ray simulation code Geant 4.10.2 was used. A conventional and effective detector system comprising five Ge detectors was assumed. We took up 38 nuclides which need to be determined for the evaluation of fission product leakage at the nuclear accident in the Fukushima nuclear power plants in Japan. Among them 12 nuclides emit gamma-rays and five nuclides of Co-60, Nb-94, Cs-134, Eu-152, and Eu-154 can be the objectives of the multiple gamma-ray detection methods. The simulation results indicate that the signal-to-noise ratio can be improved by a factor between 9.84 and 283, and the detection limit by a factor between 2.71 and 8.53 relative to the singles measurement, implying that the method can be well applied to the determination of the long-lived radioactive nuclides and will provide a quick and non-destructive analysis method.

Charged Particle Activation Analysis (CPAA) utilizing an 8-MeV proton beam has been studied for determination of 35 long-lived radioactive nuclides. We accumulated the reaction cross section and nuclear decay data by referring to nuclear database supplied by National Nuclear Data Center in Brookhaven National Laboratory. We also calculated the reaction cross sections by using statistical model code ALICE. By using the nuclear data, we have derived determination sensitivity of the radioactive nuclides relative to unit weight and specific radioactivity. The result indicates that several hardly measurable nuclides with long half-lives such as Cs-135, Pu-244, I-129, Sn-126, Mo-93, Pd-107, U-236, Cm-248, and Np-237 have high sensitivity. It may be concluded that CPAA can be applied to determination of several long-lived nuclei and will provide a quick and non-destructive analysis method.

The increased relevancy of digital technologies in the humanities and visual literacy through the use of rich media—maps, photography, video composition, big data, and interactive Web platforms—can serve as representations to communicate the study of spaces and urban life. How then does the integration of scientific, visual, and sensorial research methods become associated into the curriculum of GeoHumanities? We investigate spatial ethnography—by contextualizing three eminent risks present: societal disruption, technological failures, and political dysfunction—as a method that provides a multisensorial depiction of transformed urban spaces. These perspectives of risks are evaluated through a case study following the catastrophic events of March 2011 within a government-sanctioned 20-km evacuation zone in Fukushima, Japan. The five visual research methods—defining a route, measuring risk, interviews with stakeholders, film documentaries and photography, and the process of “thick mapping”—complete an ethnographic dossier that tests new discoveries between scientific data and the humanities into academic discourse.

The gamma-radiation has been investigated for Ni-63 produced by cold neutron capture in an enriched Ni-62 sample. The 315 gamma-rays produced were placed in a Ni-63 level scheme, in which 272 placements are new. We determined the excitation energies with 0.2-0.8 keV error and the branching ratios of 62 bound levels in Ni-63, including 30 new levels. The Q-value of the Ni-62(n, gamma)Ni-63 reaction amounts to 6837.75 +/- 0.18 keV. A large-scale shell-model calculation was performed that included the four single-particle orbits of 0f(7/2), 1p(3/2), 0f(5/2), and 1p(1/2), assuming an inert Ca-40 core for negative-parity states, and those of 1p(3/2), 0f(5/2), 1p(1/2), and 0g(9/2), assuming a Ni-56 core for positive-parity states. The energies of the low-lying Ni-63 states were successfully reproduced. A mean-field statistical-model calculation was also performed by using a self-consistent interaction between the Hartree-Fock + Bardeen-Cooper-Schrieffer method and the statistical calculation. The calculation result is consistent with the experimental level density of Ni-63.