Challenging studies by accelerator mass spectrometry for the development of environmental radiology; Status report on the analysis of Sr and Cs by AMS

Honda, Maki; Martschini, M.*; Wieser, A.*; Marchhart, O.*; Lachner, J.*; Priller, A.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*

JAEA-Conf 2022-001, p.85 - 90, 2022/11

https://doi.org/10.11484/jaea-conf-2022-001

Accelerator mass spectrometry (AMS) is an analytical method that combines mass spectrometry with a tandem accelerator, which has been used mainly in nuclear physics experiments. AMS is used to measure radionuclides with half-lives of 10-10 years. For radionuclides with half-lives of this order, the method of measuring their mass is 10-10 times more sensitive than measuring their activity. Because of this advantage, AMS has been widely applied in Earth and planetary sciences, atomic energy research, and other fields. Among the various studies, Wallner et al. (2021, 2016) have achieved excellent work in Earth and planetary sciences. For example, they have attained the ultra-sensitive analysis of Fe and Pu in environmental samples. These are radionuclides produced by rapid-neutron-capture (r-process) nucleosynthesis. Our recent work shows that a new AMS system (VERA, University of Vienna), which combines laser isobaric separation and a typical AMS system, has been successfully applied to the ultra-sensitive determination of Sr and Cs in environment. For Sr in environmental samples, the -ray measurement by the milking of the daughter nuclide Y is still the principal method, which takes 3-6 weeks. The new AMS method has a detection limit of 0.1 mBq, which is comparable to that of -ray measurement, with a more straightforward chemical treatment than -measurement. Our achievement demonstrates that AMS can be a practical new method for determining Sr in the environment.

Weinberg operator contribution to the -odd nuclear force in the quark model

Yamanaka, Nodoka*; Oka, Makoto

Physical Review D, 106(7), p.075021_1 - 075021_15, 2022/10

https://doi.org/10.1103/PhysRevD.106.075021

The contribution of the violating three-gluon interaction, proposed by Weinberg, to the short-range -odd nuclear force is evaluated in the nonrelativistic quark model. We first show that the naive leading contribution generated by the quark exchange process vanishes at sufficiently short distance within the resonating group method, by considering the one-loop level gluon exchange -odd interquark potential induced by the Weinberg operator with massive quarks and gluons. We then estimate the true leading contribution by evaluating the gluonic correction to the -odd interquark potential in the closure approximation. It is found that the resulting irreducible -odd nuclear force is comparable to that generated by the chiral rotation of the -even short-range nuclear force, where the -odd mass calculated with QCD sum rules is used as input. The explicit calculation of the electric dipole moment (EDM) of the He nucleus yields MeV. The total EDM, accounting for the intrinsic nucleon EDM, the pion-exchange and the short- range -odd nuclear force, is MeV, with the dominant effect coming from the intrinsic nucleon EDM.

Radioactive particles from a range of past nuclear events; Challenges posed by highly varied structure and composition

Johansen, M. P.*; Child, D. P.*; Collins, R.*; Cook, M.*; Davis, J.*; Hotchkis, M. A. C.*; Howard, D. L.*; Howell, N.*; Ikeda, Atsushi; Young, E.*

Science of the Total Environment, 842, p.156755_1 - 156755_11, 2022/10

https://doi.org/10.1016/j.scitotenv.2022.156755

Nuclear pasta structures at high temperatures

Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*

Physical Review D, 106(6), p.063020_1 - 063020_14, 2022/09

https://doi.org/10.1103/PhysRevD.106.063020

Kaon-baryon coupling schemes and kaon condensation in hyperon-mixed matter

Muto, Takumi*; Maruyama, Toshiki; Tatsumi, Toshitaka*

Progress of Theoretical and Experimental Physics (Internet), 2022(9), p.093D03_1 - 093D03_37, 2022/09

https://doi.org/10.1093/ptep/ptac115

On the adsorption and reactivity of element 114, flerovium

Yakushev, A.*; Lens, L.*; Dllmann, Ch. E.*; Khuyagbaatar, J.*; Jger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; Asai, Masato; Block, M.*; et al.

Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08

https://doi.org/10.3389/fchem.2022.976635

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. The first chemical experiment on Fl suggested that Fl is a noble-gas-like element, while the second studies suggested that Fl has a volatile-metal-like character. To obtain more reliable conclusion, we performed further experimental studies on Fl adsorption behavior on Si oxide and gold surfaces. The present results suggest that Fl is highly volatile and less reactive than the volatile metal, Hg, but has higher reactivity than the noble gas, Rn.

Promotion of ciprofloxacin adsorption from contaminated solutions by oxalate modified nanoscale zerovalent iron particles

Falyouna, O.*; Idham, M. F.*; Maamoun, I.; Bensaida, K.*; Ashik, U. P. M.*; Sugihara, Yuji*; Eljamal, O.*

Journal of Molecular Liquids, 359, p.119323_1 - 119323_20, 2022/08

https://doi.org/10.1016/j.molliq.2022.119323

Finding RHEED conditions sensitive to hydrogen position on Pd(100)

Kawamura, Takaaki*; Fukaya, Yuki; Fukutani, Katsuyuki

Surface Science, 722, p.122098_1 - 122098_8, 2022/08

https://doi.org/10.1016/j.susc.2022.122098

no abstracts in English

Local bifurcation with spin-transfer torque in superparamagnetic tunnel junctions

Funatsu, Takuya*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*

Nature Communications (Internet), 13, p.4079_1 - 4079_8, 2022/07

https://doi.org/10.1038/s41467-022-31788-1

Modulation of the energy landscape by external perturbations governs various thermally-activated phenomena, described by the Arrhenius law. Thermal fluctuation of nanoscale magnetic tunnel junctions with spin-transfer torque (STT) shows promise for unconventional computing, whereas its rigorous representation, based on the Neel-Arrhenius law, has been controversial. In particular, the exponents for thermally-activated switching rate therein, have been inaccessible with conventional thermally-stable nanomagnets with decade-long retention time. Here we approach the Neel-Arrhenius law with STT utilising superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determine the exponents through several independent measurements including homodyne-detected ferromagnetic resonance, nanosecond STT switching, and random telegraph noise. Furthermore, we show that the results are comprehensively described by a concept of local bifurcation observed in various physical systems. The findings demonstrate the capability of superparamagnetic tunnel junction as a useful tester for statistical physics as well as sophisticated engineering of probabilistic computing hardware with a rigorous mathematical foundation.

Single crystal growth of superconducting UTe by molten salt flux method

Sakai, Hironori; Opletal, P.; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Tokunaga, Yo; Kambe, Shinsaku; Haga, Yoshinori

Physical Review Materials (Internet), 6(7), p.073401_1 - 073401_10, 2022/07

https://doi.org/10.1103/PhysRevMaterials.6.073401

The molten salt flux method is applied as a new synthetic route for the single crystals of the spin-triplet superconductor UTe. The single crystals under an optimized growth condition with excess uranium exhibit a superconducting transition at K, which is the highest reported for this compound. The obtained crystals show a remarkably large residual resistivity ratio with respect to the room temperature value and a small residual electronic contribution in specific heat well below . These results indicate that the increase of in UTe can be achieved by reducing the disorder associated with uranium vacancies. The excess uranium in the molten salt acts as a reducing agent, preventing tetravalent uranium from becoming pentavalent and suppressing creation of uranium vacancies. At the same time, the relatively low growth temperature can suppress Te volatilization.