Search

Your search keyword '"Fujimoto, Yutaka"' showing total 971 results
Start Over Author "Fujimoto, Yutaka"
971 results on '"Fujimoto, Yutaka"'

65. Scintillation properties of lithium-6 salicylate-loaded liquid scintillators.

Author

Watanabe, Akito, Koshimizu, Masanori, Watanabe, Kenichi, Sato, Atsushi, Fujimoto, Yutaka, and Asai, Keisuke

Abstract

The limited availability of conventional 3He proportional counters provides impetus for developing novel neutron detectors. As a candidate, lithium-6-loaded liquid scintillators with neutron/gamma pulse shape discrimination (n–γ PSD) capabilities have been developed. However, the trade-off relationship between the 6Li-loading amount and scintillation light yield is a significant problem. This is because 6Li-loading involves the addition of non-luminescent materials, which cause non-radiative relaxation of the excited states. Therefore, aiming to reduce non-radiative relaxation, we chose lithium-6 salicylate (6LiSal), which shows fluorescence in the visible light region, as a chemical for 6Li-loading. In this study, we analyzed the photoluminescence/scintillation properties based on the Förster resonance energy transfer and investigated the optimal content for obtaining a high light yield. By maximizing the sequential energy transfer from the solvent (toluene) to the phosphor (POPOP), a high light yield 6Li-loaded liquid scintillator (4220 photons per MeV under gamma-ray irradiation) with a 6Li concentration of approximately 0.1 wt% was developed. Thermal neutron events were successfully detected with a light yield of 3970 photons per neutron, which is more than three times higher than those of other organic scintillators. In addition, focusing on the triplet–triplet annihilation process and further optimizing the component for the n–γ PSD, the thermal neutron and gamma-ray events were successfully separated. The developed high light yield 6Li-loaded liquid scintillators show n–γ PSD capabilities and can be promising candidates as alternative detectors to the 3He proportional counter. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

66. Development of plastic scintillators loaded with perovskite quantum dots and wavelength shifting molecules.

Author

Sato, Atsushi, Fujimoto, Yutaka, Asai, Keisuke, and Koshimizu, Masanori

Abstract

We have deloveloped plastic scintillators loaded with perovskite quantum dots (QDs) to obtain efficient scintillation and enhanced detection efficiency of high-energy photons such as X-rays and gamma rays. In previous studies, the loading of the perovsite QDs was not successful to achieve efficient scintillation owing to the severe self-absorption of the QD emission, which is caused by small Stokes shift of the QDs. In the present study, we added wavelength shifting molecules to suppress the self-absorption. Among three samples, we have succeeded in enhancement in the scintillation light yield and shortening of the scintillation decay by the suppression of the self-absorption in polustyrene-based plastic scintillators added with butyl-PBD, QD-P450, and Coumarin6, and butyl-PBD, QD-P510, and Nile red. This result indicates that it is necessary to avoid the self-absorption to fully exploit the fast and efficient emission of the perovskite QDs. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results