Accelerator mass spectrometry (AMS) has been recognized as the most sensitive analytical method for the isotopic ratio ¹²⁹I/¹²⁷I, and its limit of detection reaches as low as ¹²⁹I/¹²⁷I < 2×10^-14. Recently triple quadrupole ICP-MS (ICP-MS/MS) is becoming an alternative analytical method for the rather high isotopic ratio range, ¹²⁹I/¹²⁷I > 10^-8. Absolute ICP-MS/MS measurements require reliable standard materials for calibration. In this study, ¹²⁹I standard solutions “tRIC-1” and “tRIC-2” were prepared from a laboratory-stored ¹²⁹I solution and the ¹²⁹I radioactivity standard of NIST SRM 4949d, respectively. The isotopic ratios of ¹²⁹I/¹²⁷I were determined to be (6.54 ± 0.23) × 10^-5 for tRIC-1 and (3.41 ± 0.12) × 10^-6 for tRIC-2 from the measurement results of AMS (¹²⁹I/¹²⁷I ratio) and ICP-MS/MS (¹²⁷I concentration). From the ¹²⁹I and ¹²⁷I concentrations each calibration line in ICP-MS/MS was used to calculate the ¹²⁹I/¹²⁷I isotopic ratios which were (6.51 ± 0.26) × 10^-5 for tRIC-1 and (3.34 ± 0.13) × 10^-6 for tRIC-2. These isotopic ratios of ¹²⁹I/¹²⁷I agree with the value from AMS. It was proved that the two home-made standard solutions could be measured using the latest ICP-MS/MS and reliable isotopic ratios of ¹²⁹I/¹²⁷I were obtained.

The chemical effect of the muon transfer process from muonic hydrogen atom was examined for benzene and cyclohexane under low pressure gaseous conditions. The muon transfer rates were investigated by measuring the resulting muonic X-rays resulting from muon irradiation of hydrogen and neon gas mixtures. The muon transfer rates to benzene and cyclohexane carbon atoms were very similar in the gaseous state. The results differed from previous results obtained for muon and pion transfer rates to benzene and cyclohexane under high density liquid conditions. It was concluded that the difference originated from the atomic muon state of the muonic hydrogen atoms with a large radius.

Heavy ion (Fe³⁺) irradiation or gamma-ray irradiation of silicon carbide (β-SiC) was done to evaluate the radiation effect on hydrogen isotope retention in SiC. Thereafter, 1 keV D₂⁺ implantation or D₂ gas exposure was performed, and their D retentions were evaluated by thermal desorption spectroscopy (TDS). The D₂ TDS spectra consisted of two desorption stages, namely the desorption of D bound to Si as the Si-D bond and C as the C-D bond. The D retention for Fe³⁺ irradiated SiC at the lowest D₂⁺ fluence of 0.1 × 10²² D⁺ m^-2 was lower than that for unirradiated SiC. It was expected that the displaced C atoms would be accumulated near the surface region by Fe³⁺ irradiation, leading to their dynamic desorption in methane molecules. For gamma-ray irradiation, C or Si with dangling bonds were formed, which enhanced D trapping. It was concluded that the collision process caused during Fe³⁺ irradiation induced the dissociation of SiC matrix and C aggregates near the surface region, but the electron excitation by gamma-ray irradiation dissociated the single Si-C bond and the quick D trapping by dangling bonds enhanced D retention in SiC.

A sequential separation technique using an anion-exchange column developed in the previous works has the potential to completely separate picograms of Am from the lanthanides using mixtures of acetic acid, hydrochloric acid, and nitric acid as the eluents, without any functional ligands or special columns. This experimental result implies that ultra-trace actinides, including Am, Pu, U, and Th in environmental samples can be sequentially separated by combination of these mixed-media eluents and an anion exchange column.

Chemical, mineralogical and radiometric investigation studies were executed on a representative phosphorite sample collected from El-Sibaiya East area to evaluate its suitability for the alkaline leaching of its uranium content. The uranium alkaline leaching was carried out in three phases using Na₂CO₃ and a mixture of Na₂CO₃/NaHCO₃ with/without an oxidant (Na₂O₂). Factors include; Na₂CO₃, NaHCO₃, Na₂O₂ concentrations; digestion temperature, reaction time and ore fineness were studied and optimized. The results pointed to that the best leaching efficiency of uranium (83.2%) was conducted using the mixture solution of Na₂CO₃/NaHCO₃ (0.5M) in the presence of 2.5% Na₂O₂ (w/w). The other conditions affected the leaching process were studied and optimized as 80 oC (leaching temperature), 3h (leaching time), 44μm (ore grain size) and a solid/liquid ratio of 2/25. The leached uranium was recovered by precipitation using NaOH solution where the precipitated product was defined by the XRD as sodium diuranate (Na₂U₂O₇) of high purity.

Rapid chemical experiment targeting single atoms combined with identification via alpha-particle measurement is required for superheavy element chemistry. Herein, successful development of two types of experimental methods of superheavy element chemistry: solid-liquid extraction and precipitation, is presented. The chemical behaviors of Zr and Hf (homologues of element 104, Rf), and Th (pseudo homologue) were investigated using carrier-free RI tracers. Through these studies, rapid chemical reaction systems were found and the comparative data to discuss the chemical properties of Rf were obtained. In addition, automated chemistry apparatuses for extraction and precipitation were developed and their performance was evaluated using the short-lived isotopes of Zr and Hf, which were transported online from the nuclear reaction chamber in the accelerator room by a He/KCl gas-jet system. From those results, the newly developed methods were both found to be applicable to ²⁶¹Rf experiments, and suitable experimental conditions to study the chloride complexation (solid-liquid extraction) and hydroxide complexation (coprecipitation) of Rf were determined.