Consideration of the dielectric response for radiation chemistry simulations

Toigawa, Tomohiro; Kai, Takeshi; Kumagai, Yuta; Yokoya, Akinari*

Journal of Chemical Physics, 160(21), p.214119_1 - 214119_9, 2024/06

https://doi.org/10.1063/5.0211089

The spur reaction is crucial for determining radiolysis or photolysis in liquid, but the spur expansion process has yet to be elucidated. One reason is the need to understand the role of the dielectric response of the solvating molecules surrounding the charged species generated by ionization. The dielectric response corresponds to the time evolution of the permittivity and might affect the chemical reaction-diffusion of the species in a spur expansion process. This study examined the competitive relationship between reaction-diffusion kinetics and the dielectric response by solving the Debye-Smoluchowski equation while considering the dielectric response. The Coulomb force between the charged species gradually decreases with the dielectric response. Our calculation results found a condition where fast recombination occurs before the dielectric response is complete. Although it has been reported that the primary G-values of free electrons depend on the static dielectric constant under low-linear-energy transfer radiation-induced ionization, we propose that considering the dielectric response can provide a deeper insight into fast recombination reactions under high-linear-energy transfer radiation- or photo-induced ionization. Our simulation method enables the understanding of fast radiation-induced phenomena in liquids.

Measurement and evaluation of isotope effect between tritium and deuterium on diffusion and surface recombination in/on nickel using ion driven permeation method (Cooperative research)

Nakamura, Hirofumi; Nishi, Masataka; Sugisaki, Masayasu*

JAERI-Research 2003-018, 32 Pages, 2003/09

JAERI-Research-2003-018.pdf:1.32MB

Tritium transport behavior in materials, which is essential for the safety evaluation of the fusion reactor, has to be evaluated by either tritium properties or extrapolated value from protium or deuterium (D) to tritium (T) using the isotope effect theory. However, there are still some uncertainties on estimation of T behavior in materials, because there are only a few T transport properties data in materials, and it is not completely proven the application of the isotope effect theory to T due to the lack of T data. Therefore, in order to understand the tritium transport properties in materials, isotope effects on diffusion and surface recombination between T and D in/on nickel, whose hydrogen transport properties were well known, were investigated by comparing the obtained properties of T with those of D measured under the same conditions with the ion driven permeation method. Though obtained diffusion coefficient of T was larger than that of D, and activation energy of diffusion of T was smaller than that of D as the contrary to the classical diffusion theory, those were shown to be explained with a modified diffusion theory by introducing higher vibration temperatures in nickel than previous reported values. In addition, the isotope effect on surface recombination coefficient between D and T was shown to be explained using a modified solution model as well as diffusion.

Review of soft X-ray laser researches and developments

Daido, Hiroyuki

Reports on Progress in Physics, 65(10), p.1513 - 1576, 2002/10

https://doi.org/10.1088/0034-4885/65/10/204

no abstracts in English

Angle-differential cross sections for radiative recombination and the photoelectric effect in the and shells of one-electron systems calculated within an exact relativistic description

Ichihara, Akira; Eichler, J.*

Atomic Data and Nuclear Data Tables, 79(2), p.187 - 222, 2001/11

https://doi.org/10.1006/adnd.2001.0868

no abstracts in English

Tritium permeation behavior implanted into pure tungsten and its isotope effect

Nakamura, Hirofumi; Hayashi, Takumi; Kakuta, Toshiya*; Suzuki, Takumi; Nishi, Masataka

Journal of Nuclear Materials, 297(3), p.285 - 291, 2001/09

https://doi.org/10.1016/S0022-3115(01)00635-3

The isotope effect on the implantation-driven permeation of pure tritium (T) and deuterium (D) through nickel was investigated, respectively. The rate-determining processes of backward flow at the upstream surface and permeation at the down-stream surface were found to be as follows: recombination on up-stream surface and diffusion at down-stream side in a lower temperature region, whereas recombination on both surfaces in a higher temperature region for T and D, respectively. The diffusion coefficients of T and D derived by analyzing the obtained transient data of permeation in the lower temperature region were in good agreement with literature data of deuterium. The obtained activation energy of diffusion for T and D suggested the tendency of mass dependence. The surface recombination coefficients for both isotopes were also derived and showed in good agreement with literature data. As a result, the experimental results indicated the surface recombination could be attributed to the isotope effect of the permeation between T and D rather than the diffusion.

Multichordal charge exchange recombination spectroscopy on the JT-60U tokamak

Koide, Yoshihiko; Sakasai, Akira; Sakamoto, Yoshiteru; Kubo, Hirotaka; Sugie, Tatsuo

Review of Scientific Instruments, 72(1), p.119 - 127, 2001/01

https://doi.org/10.1063/1.1332115

no abstracts in English

Collisional effects on population inversion in optical-field-ionized plasmas

Sagisaka, Akito*; Nagashima, Keisuke; Yamagiwa, Mitsuru; Matoba, Toru;

Journal of the Physical Society of Japan, 68(4), p.1221 - 1227, 1999/04

https://doi.org/10.1143/JPSJ.68.1221

no abstracts in English

Spectroscopic study of the W-shaped divertor in JT-60U

Kubo, Hirotaka; Higashijima, Satoru; Takenaga, Hidenobu; Shimizu, Katsuhiro; Kumagai, Akira*; Ishijima, Tatsuo*; Suzuki, Shingo*; Itami, Kiyoshi; Sugie, Tatsuo; Sakasai, Akira; et al.

Proc. of 1998 ICPP & 25th EPS Conf. on Contr. Fusion and Plasma Physics, 22C, p.427 - 430, 1998/00

no abstracts in English

Photon angular distributions from radiative electron capture in relativistic atomic collisions

J.Eichler*; Ichihara, Akira; Shirai, Toshizo

Physical Review A, 51(4), p.3027 - 3035, 1995/04

https://doi.org/10.1103/PhysRevA.51.3027

no abstracts in English

Ion-driven permeation of deuterium in metals

W.Shu*; Okuno, Kenji; Hayashi, Yasunori*

JAERI-M 93-043, 62 Pages, 1993/03

JAERI-M-93-043.pdf:1.37MB

no abstracts in English