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Shimizu, Mayuko; Sano, Naomi; Suzuki, Kazuhiro
Nagoya Daigaku Nendai Sokutei Kenkyu, 1, p.36 - 43, 2017/03
We established a CHIME monazite dating method using R
= 100 mm spectrometers and a provenance analysis method using heavy minerals for the dating and analysis of minerals. CHIME dating has traditionally been performed with conventional R = 140 mm spectrometers for measurement of U, Th, and Pb. These spectrometers, however, have low count rates in measurements of Pb. We used a JEOL JXA-8530F FE-EPMA equipped with R = 100 mm spectrometers, a system installed at Tono Geoscience Center in 2014, for the CHIME dating of monazite. We corrected the spectral interferences peculiar to R = 100 mm spectrometers by the method of AA mli and Griffin (1975) for monazite analyses. We calculated the correction factors by a new interference correction method using natural monazites. We also established a quick quantitative analysis and identification method for heavy minerals using the EPMA.
Shibata, Kenji; Shimizu, Mayuko; Suzuki, Kazuhiro
Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 26, p.126 - 131, 2015/03
no abstracts in English
F
irradiated with two-frequency CO laser lightsYokoyama, Atsushi; Oba, Hironori; Hashimoto, Masashi; Katsumata, Keiichi; Akagi, Hiroshi; Ishii, Takeshi*; Oya, Akio*; Arai, Shigeyoshi*
Applied Physics B, 79(7), p.883 - 889, 2004/11
Times Cited Count：10 Percentile：42(Optics)Silicon isotope separation has been done utilizing the Infrared Multiphoton Dissociation of SiF irradiated with two-frequency CO laser lights. The two-frequency excitation method improved the separation efficiency with keeping the high enrichment factors. For example, SiF with the 
Si fraction of 99.4 % was obtained at 40.0 % dissociation of SiF after the simultaneous irradiation of 100 pulses with 966.23 cm
photons (0.089 J/cm
) and 954.55 cm photons (0.92 J/cm), while 1000 pulses were needed to obtain 99.0 % of Si at 27.2 % dissociation in the case of single frequency irradiation at 954.55 cm (0.92 J/cm). The single-step enrichment factors of 
Si and 
Si increased with increasing SiF pressure. The reason for this enhancement has been discussed in terms of the rotational and vibrational relaxations by collisions with ambient gases.
Shibata, Kenji; Shimizu, Mayuko; Suzuki, Kazuhiro; Sueoka, Shigeru; Niwa, Masakazu
no journal, ,
The CHIME (Chemical Th-U-total Pb isochron method) dating has been performed on JEOL JXA-8530F FE-EPMA introduced in Tono Geoscience Center of Japan Atomic Energy Agency. Analysis of Pb on conventional spectrometers have disadvantage in count rate. JXA-8530F equipped with three R=100 provides significant shortening in analyzing time. Spectral interferences peculiar to R=100 mm spectrometers are found to be collected on the monazite analyses. The intrinsic responses of the R=100 mm counting systems with a PET crystal and a sealed Xe detector for PbMb are around ten times higher than that of the JCXA-733 counting systems. The measurement time required for a spot is ca. 35 minutes. The advanced procedure carried out 425
25 Ma for monazite from Cooma granite in southeastern Australia, which had dated by SHRIMP as 432.83.5 Ma. The CHIME monazite age of the Kojaku granite in southwestern Japan is 685 Ma that accords well with the LA-ICP-MS U-Pb zircon ages of 68.50.7 Ma.
