Microdosimetry study of proton quality factor using analytic model calculations

Papadopoulos, A.*; Kyriakou, I.*; Matsuya, Yusuke; Incerti, S.*; Daglis, I. A.*; Emfietzoglou, D.*

Applied Sciences (Internet), 12(18), p.8950_1 - 8950_20, 2022/09

https://doi.org/10.3390/app12188950

The quality factor (Q) is the index which is used when evaluating the stochastic (e.g., carcinogenic) risk of diverse ionizing radiations. While the Q value can be commonly determined from the Linear Energy Transfer (LET), more elaborate approaches are based on the microdosimetric parameter lineal energy (y) calculated either by analytical model or Monte Carlo (MC) simulations. However, the developing of the model for determining the Q value is still ongoing worldwide for realizing the precise risk assessment. In this study, various generalized analytical models that account for both -ray transport and energy-loss straggling effects are utilized to evaluate the Q values over the proton energy range 1-250 MeV. The results revealed that the LET-based ICRP Report 60 recommendations underestimate the microdosimetric-based Q values of protons with energy below 100 MeV, which was also confirmed by using MC simulation data on the y values. The present work shows that analytic models may offer a practical alternative to computer-intensive MC simulations for calculating Q values based on the microdosimetric methodologies. In future study, we are planning to compare the y spectra and subsequent calculations of Q based on new MC data with the latest versions of Geant4-DNA and PHITS track structure codes which make use of different physics models.

Bias effects on g- and s-factors in Westcott convention

Harada, Hideo

Applied Sciences (Internet), 11(14), p.6558_1 - 6558_20, 2021/07

https://doi.org/10.3390/app11146558

For accuracy improvement of neutron activation analysis and neutron capture cross section, bias effects are investigated on g- and s-factors in the Westcott convention. As origins of biases, a joining function shape, neutron temperature and sample temperature, have been investigated. Biases are quantitatively deduced for two 1/v isotopes (Au, Co) and six non-1/v isotopes (Am, Eu, Rh, In, Hf, Ra). The s-factor calculated with a joining function deduced recently by a detailed Monte Carlo simulation is compared to s-factors calculated with traditional joining functions by Westcott. The results show the bias induced by sample temperature is small as the order of 0.1% for g-factor and the order of 1% for s-factor. On the other hand, biases induced by a joining function shape for s-factor depend significantly on both isotopes and neutron temperature. As the result, reaction rates are also affected significantly as well. The bias size on reaction rate is given in the case of epithermal neutron index r = 0.1, for the eight isotopes.

Proposal of laser-induced ultrasonic guided wave for corrosion detection of reinforced concrete structures in Fukushima Daiichi Nuclear Power Plant decommissioning site

Furusawa, Akinori; Takenaka, Yusuke; Nishimura, Akihiko

Applied Sciences (Internet), 9(17), p.3544_1 - 3544_12, 2019/09

https://doi.org/10.3390/app9173544

Remote-controlled, non-destructive testing is necessary to detect corrosion of the reinforced concrete structures at the Fukushima Daiichi Nuclear Power Plant (NPP) de-commissioning site. This work aims to demonstrate that laser-induced ultrasonic guided wave technology can be applied to achieve this task. Hence, accelerated electrolytic corrosion is performed on a reinforced concrete specimen fabricated by embedding a steel rod into mortar. Waveforms of the laser-induced ultrasonic guided wave on the rod are measured with a previously employed piezoelectric transducer (PZT) probe, for each fixed corrosion time. Based on the results of Fourier and wavelet transforms of the waveforms, issues concerning the detection and extent of rebar corrosion are discussed. It is exhibited that the changes in bonding strength due to corrosion are distinguishable in the frequency domain of the ultrasonic signal.

Evaluation of a wet chemistry method for isolation of cyclotron produced [At] astatine

Balkin, E. R.*; Hamlin, D. K.*; Gagnon, K.*; Chyan, M.-K.*; Pal, S.*; Watanabe, Shigeki; Wilbur, D. S.*

Applied Sciences (Internet), 3(3), p.636 - 655, 2013/09

https://doi.org/10.3390/app3030636