日本原子力学会九州支部第175回講演会のご案内
Jean-Marc Costantini博士(CEA-サクレ―研究所)、および小川達彦博士（日本原子力研究開発機構）をお迎えして下記のように講演会を開催します。皆様、奮ってご参加ください。なお、講演は両博士の講演共に英語で行われます。
日時：平成30年5月11日（金）15：00～18：00
場所：九州大学伊都キャンパスウエスト2号館 エネルギー量子工学
821号セミナー室
講演1：
講師：小川 達彦 氏 （日本原子力研究開発機構）
講演タイトルおよび概要
“Application of radiation biology calculation codes for irradiation effects”
Irradiation effects on materials depend on various beam parameters such as particle species, incident energy, particle flux, etc. Prediction of irradiation effects based on numerical simulation would encourage the advance of experimental studies; however, it is very challenging because irradiation effects are generally a result of multiple processes such as transport of secondary electrons, propagation of heat, and spread of radicals.
In this seminar, some successful examples of irradiation effect simulation, conducted using the calculation codes developed for radiation biology studies, are reported to discuss further expansion of irradiation effect simulation studies. In particular, prediction of organic scintillator light yield based on the nano-scale radiation transport simulation is explained in detail. Brief introduction of the calculation codes used for these studies, namely PHITS and RITRACKS, are also given.
講演２：
講師：Jean-Marc COSTANTINI氏 （フランス原子力庁(CEA)-サクレ―研究所）
講演タイトルおよび概要
“Cathodoluminescence induced in oxides by high energy electrons”
Cathodoluminescence (CL) is generally used as an analytical means with low-energy electron excitations ( 100 keV). However, it was also employed for point-defect studies such as oxygen vacancies in oxides or impurities in semiconductors, like photoluminescence or radioluminescence. The CL was applied with high-energy electrons in a high-voltage electron microscope (HVEM) for energies ranging between 400 keV and 1,250 keV in view to study point-defect formation in oxides.
First results were published on sapphire (-Al2O3) and yttria-stabilized zirconia (ZrO2: Y or YSZ) single crystal plates at RT. The main CL bands centered at photon energies of about 3.8 eV and 4.1 eV were assigned to F+ centers (oxygen vacancies with 1+ charge state) produced by displacement damage of oxygen atoms in sapphire and YSZ, respectively, for energies higher than 400 keV. For sapphire, the growth and saturation of the main 3.8-eV band as a function of irradiation time, for a constant beam flux, was interpreted by a first-order kinetic model of point-defect formation and recombination. Moreover, a flat maximum in intensity of the latter band versus electron energy was evidenced between 400 keV and 600 keV.
We report new data and related analysis on the temperature, beam-flux and electron-energy dependence of CL bands for both sapphire and YSZ. Moreover, first results on magnesium aluminate spinel (MgAl2O4) and titanium dioxide, or titania (TiO2) are also reported in relation to the radiation damage process. For spinel, a CL band centered at 4.9 eV is assigned to F-center formation above 800 keV in agreement with UV-visible absorption data. Interpretations of the temperature and electron-energy dependence of CL bands for sapphire and YSZ are attempted on the basis of simple approximations.
連絡先：
安田和弘 九州大学工学研究院エネルギー量子工学部門
Tel:092-802-3487, mail:yasudak@nucl.kyushu-u.ac.jp