Properties of a Windowless Gas-Flow G-M Counter for TSEE

A windowless gas-flow G-M counter with an internal sample holder was newly designed for detection of TSEE. Properties of the counter were studied for various temperatures of the sample holder and for gas-flow rates. The plateau region of the characteristic curve remarkably shifts to the lower side of anode voltage for higher temperatures of the sample holder and for smaller gas-flow rates. The counting rate of the detector for a fixed anode voltage depends to the temperature of the gas in the sensitive volume

飛行中電子のK殻電子による二光子消滅

京都大学0048新制・論文博士工学博士乙第3539号論工博第1043号新制||工||397(附属図書館)5379UT51-53-C230(主査)教授 清水 栄, 教授 兵藤 知典, 教授 向坂 正勝学位規則第5条第2項該当Kyoto UniversityDA

Thermoluminescence age of quartz xenocrysts in basaltic lava from Oninomi monogenetic volcano, northern Kyushu, Japan

We determined the eruption age of basaltic rocks by application of thermoluminescence (TL) method, which is often used for TL dating, to quartz. Mafic magma only rarely includes quartz because of their mutual disequilibration. The basaltic lavas reported herein include quartz as xenocrysts, as corroborated by their rounded or anhedral shape. The basaltic lava used for this study is from the Oninomi monogenetic volcano in northern Kyushu, Japan. The volcano eruption was estimated as occurring 7.3–29 ka because the lava exists between two widespread tephras: Aira-Tanzawa ash (26–29 ka) and Kikai-Akahoya ash (7.3 ka). We succeed-ed in collecting ca. 200 mg of quartz by decomposition of 30 kg of the lava samples. TL measurements for the lava indicate the eruption age as 15.8 ± 2.5 ka, which is fairly consistent with the stratigraphical estimation. Although the TL method has played a considerable part in constraining the timescale of Quaternary events, its application has been limited to silicic samples. The present result demonstrates the availability of quartz for dating even of mafic rock

Sourcing of Ancient Pottery by Non-Destructive Analysis I

The non-destructive analysis of ancient pottery sherds (Haji and Sue) were done by means of energy-dispersive X-ray fluorescence spectrometry. The results were compared with those obtained by destructive (powdered and pressed) analyses of the same samples. The carbon and natural glaze attached to the vessel surfaces had significant effects on the analytical data, but these effects were minimized by measuring the surface of optimum condition. The effect of surface geometry of the pottery was also examined. Non-destructive analysis by X-ray fluorescence spectrometry is expected to be useful for the sourcing of ancient pottery, assuming that sourcing them would have been possible by using powdered samples

Quartz OSL dating of sand dunes in Ghaggar Basin, northwestern India

Several studies have used luminescence dating to investigate sand mobilization activity in extreme western areas and the southern margin of the Thar Desert, India. However, room exists for a chronology of sand profiles for the northern margins of the Thar Desert. The Ghaggar River flood plain at Rajasthan, northwestern India, in the northern margin of the Thar Desert, is bordered by sand dunes. Elucidation of the environmental changes of the Ghaggar Basin requires knowledge of many aspects of sand dune formation. We measured optically stimulated luminescence (OSL) using the single aliquot regenerative-dose (SAR) protocol for sand of eight palaeo-dunes and two flood silts of both sides of the present Ghaggar Basin and Chautang Basin flood plains. Their OSL ages were obtained respectively, as 15–10 ka or 5 ka, and 9–8 ka. Results of this study reinforce the hypothesis that sand dune deposition had started or had already been completed by 15‐10 ka. Aeolian deposition was subdued by enhanced moisture during 9–8 ka. Our interpretation is that, at least since 5 ka, the scale of the flood plain of the Ghaggar River has remained equivalent to that of the present day