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Esaka, Fumitaka; Watanabe, Kazuo; Fukuyama, Hiroyasu; Onodera, Takashi; Esaka, Konomi; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu
Journal of Nuclear Science and Technology, 41(11), p.1027 - 1032, 2004/11
Times Cited Count：60 Percentile：95.55(Nuclear Science & Technology)A new particle recovery method and a sensitive screening method were developed for subsequent isotope ratio analysis of uranium particles in safeguards swipe samples. The particles in the swipe sample were recovered onto a carrier by means of vacuum suction 8211; impact collection method. When grease coating was applied to the carrier, the recovery efficiency was improved to 48 %, which is superior to that of conventionally-used ultrasoneration method. Prior to isotope ratio analysis with secondary ion mass spectrometry (SIMS), total reflection X-ray fluorescence spectrometry (TXRF) was applied to screen the sample for the presence of uranium particles. By the use of Si carriers in TXRF analysis, the detection limit of 22 pg was achieved for uranium. By combining these methods with SIMS, the isotope ratios of 
U/
U for individual uranium particles were efficiently determined.
Esaka, Fumitaka; Watanabe, Kazuo; Onodera, Takashi; Taguchi, Takuji; Magara, Masaaki; Usuda, Shigekazu
Spectrochimica Acta, Part B, 58(12), p.2145 - 2155, 2003/12
Times Cited Count：20 Percentile：62.28(Spectroscopy)In order to improve the sensitivity of elemental analysis for aerosol particles by total-reflection X-ray fluorescence spectrometry (TXRF), silicon wafer carriers with diameters of 25 mm were selected and prepared for direct impact collection and subsequent analysis. The detection limits of elements on the carrier were determined and found to be superior to those on glassy carbon and quartz glass carriers used in previous studies. By using the silicon wafer carriers, aerosol particles with the sizes of 
2.0 
m, 0.3-2.0 m and 0.05-0.3 m were collected at Ibaraki in Japan from January to August 2002 and analyzed by TXRF. Selenium Consequently, the elements with the concentration of ng/m
&8211; pg/m in the particles were successfully detected. The results revealed that K, V, Zn, Br and Pb were concentrated in fine particles, which is presumed to arise from anthropogenic sources. In contrast, Ca, Ti and Fe were contained in coarse particles, which is presumed to arise from soil.
Esaka, Fumitaka; Watanabe, Kazuo; Magara, Masaaki; Hanzawa, Yukiko; Usuda, Shigekazu
Journal of Trace and Microprobe Techniques, 19(4), p.487 - 496, 2001/11
Times Cited Count：9 Percentile：30.07(Chemistry, Analytical)The capability of total-reflection X-ray fluorescence spectrometry (TXRF) technique was studied to screen a swipe sample for uranium content, which was employed to decide on the further isotopic ratio measurements by secondary ion mass spectrometry (SIMS) for safeguards environmental sample analysis. A part of the measurement system of TXRF was modified to be able to use the same glassy carbon carrier for SIMS analysis. Particles in the swipe sample were recovered on the carbon carrier. The relative sensitivities of 11 elements including uranium were determined using selenium as an internal standard. The detection limit of uranium was 0.4 ng. The screening technique studied was applied to the practical swipe samples taken from the laboratories. The results confirm that TXRF can be a promising screening technique for uranium in swipe samples for safeguards environmental sample analysis.
