Although E^' defect center in silicate glass and crystalline quartz was discovered for an excellent dosimetry for ultra-high level radiation above 10⁴ Gy (Wieser and Regulla, 1990), in this work, Ge center in reagent quartz and HOHC (hydronium ion combined with oxygen hole center) in silicon dioxide made from silicon tetraethoxide were found, respectively, to be useful dosimetries up to 2000 Gy and 6000 Gy in the middle level radiation. The use of other defect centers such as vacancy or valence alteration radicals of E^' (oxygen vacancy), POR (peroxyl radical) and NBOHC (non-bridging oxygen hole center), and besides, the centers due to Al or Ti impurities were, on the contrary, inadequate for the dosimetry in above ranges.

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Koganegahara volcano is a large Quaternary composite volcano situated in the southwest of the Tomuraushi volcano group in Central Hokkaido, Japan. The lowermost eruptive units of the Koganegahara volcano have previously been dated at about 1.1 Ma. In this study, two lava samples from the uppermost eruptive units of the eastern and central parts of the volcano are dated, giving K-Ar ages of 0.70±0.02 Ma and 0.70±0.01 Ma. This indicates that the Koganegahara volcano was active for 400000 years from 1.1 to 0.7 Ma. Furthermore, based on previously reported and new age data, the K-Ar ages appear to be concentrated around 1.1-1.0 Ma and 0.75-0.7 Ma, suggesting that volcanic activity peaked in these periods.

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Several quartz samples containing one or two impurities were synthesized under the ambient pressure and the hydrothermal conditions by using the starting materials prepared from high purity silicon dioxide and silicon tetraethoxide. Phase transition from cristobalite to quartz occurred in the cases of coexistence of Li ion with the concentration of which are above 600 ppm under the ambient and above 50 ppm under the 100 MPa pressure. Although impurity elements usually detected in natural quartz can be doped into in the lattice in a couple with Li, cations with larger ionic radius such as Ca and K ions did not enter at ambient pressure. Under the hydrothermal condition, almost cations can be doped into the lattice as a single dopant. Such incorporated impurities to synthetic quartz were confirmed by ESR, X-ray diffraction measurement and thermal neutron irradiation. Unit cell volume of the doped quartz shows unique variation with the ionic radius of impurity ions. Lattice strain estimated from X-ray diffraction peak profiles around 90 Bragg angle (2θ) was very sensitive to the content of dopant. ESR signals showed that there exist trace Al, Na and Li in synthetic quartz made of 99.999% reagent.

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