Controlling Th isomeric state population in a VUV transparent crystal.

The radioisotope thorium-229 (Th) is renowned for its extraordinarily low-energy, long-lived nuclear first-excited state. This isomeric state can be excited by vacuum ultraviolet (VUV) lasers and Th has been proposed as a reference transition for ultra-precise nuclear clocks. To assess the feasibility and performance of the nuclear clock concept, time-controlled excitation and depopulation of the Th isomer are imperative.

Laser spectroscopy of triply charged Th isomer for a nuclear clock.

Thorium-229 (Th) possesses an optical nuclear transition between the ground state (Th) and low-lying isomer (Th). A nuclear clock based on this nuclear-transition frequency is expected to surpass existing atomic clocks owing to its insusceptibility to surrounding fields. In contrast to other charge states, triply charged Th (Th) is the most suitable for highly accurate nuclear clocks because it has closed electronic transitions that enable laser cooling, laser-induced fluorescence detection and state preparation of ions.

Tumor Targeting of At-Labeled Antibody under Sodium Ascorbate Protection against Radiolysis.

Astatine-211 (At) is an alpha emitter applicable to radioimmunotherapy (RIT), a cancer treatment that utilizes radioactive antibodies to target tumors. In the preparation of At-labeled monoclonal antibodies (At-mAbs), the possibility of radionuclide-induced antibody denaturation (radiolysis) is of concern. Our previous study showed that this At-induced radiochemical reaction disrupts the cellular binding activity of an astatinated mAb, resulting in attenuation of antitumor effects, whereas sodium ascorbate (SA), a free radical scavenger, prevents antibody denaturation, contributing to the maintenance of binding and antitumor activity.

Coprecipitation with samarium hydroxide using multitracer produced through neutron-induced fission of U toward chemical study of heavy elements.

For new chemical studies on heavy elements, we previously investigated the coprecipitation behaviors with samarium hydroxide for various elements. Herein, we report the coprecipitation experiment using multitracer produced by neutron-induced fission of U. The coprecipitation behaviors of 10 elements were investigated: new data were obtained for Sr, Ru, I, Pm, and Np.

Co-precipitation behaviour of single atoms of rutherfordium in basic solutions.

All superheavy elements (SHEs), with atomic numbers (Z) ≥104, have been artificially synthesized one atom at a time and their chemical properties are largely unknown. Because these heavy nuclei have short lifetimes as well as extremely low production rates, chemical experiments need to be carried out on single atoms and have mostly been limited to adsorption and extraction. We have now investigated the precipitation properties of the SHE Rf (Z = 104).

Absolute X-ray energy measurement using a high-accuracy angle encoder.

This paper presents an absolute X-ray photon energy measurement method that uses a Bond diffractometer. The proposed system enables the prompt and rapid in situ measurement of photon energies over a wide energy range. The diffractometer uses a reference silicon single-crystal plate and a highly accurate angle encoder called SelfA.

Observation of the chemical reaction equilibria of element 104, rutherfordium: solid-liquid extraction of Rf, Zr, Hf and Th with Aliquat 336 resin from HCl.

We successfully observed the equilibrium state of the chemical reactions for superheavy elements on a one-atom-at-a-time scale; we investigated the time dependence of the extraction behaviour of element 104, Rf. The distribution coefficient of Rf in 9 M HCl was found to be higher than those of its homologous elements, probably due to differences in the chloride complexation of Rf.

Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements.

To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors.