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Journal Articles

An Examination of rapid analysis of $$^{226}$$Ra in natural water samples by ICP-MS

Tomita, Jumpei; Ozawa, Mayumi; Ohara, Yoshiyuki; Miyamoto, Yutaka

KEK Proceedings 2021-2, p.130 - 134, 2021/12

no abstracts in English

Journal Articles

Optimization of SIMS-APM for high enrichment uranium particles including higher uranium hydride

Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka

KEK Proceedings 2021-2, p.146 - 150, 2021/12

no abstracts in English

Journal Articles

Age determination analysis of a single uranium particle for safeguards

Suzuki, Daisuke; Tomita, Ryohei; Tomita, Jumpei; Esaka, Fumitaka; Yasuda, Kenichiro; Miyamoto, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 328(1), p.103 - 111, 2021/04

 Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)

An analytical technique was developed to determine the age of uranium particles for safeguards. After the chemical separation of uranium and thorium, the $$^{230}$$Th/$$^{234}$$U ratio was measured using single-collector inductively coupled plasma mass spectrometry and a $$^{233}$$U-based reference material comprising a certain amount of $$^{229}$$Th as a progeny nuclide of $$^{233}$$U. The results allowed us to determine the purification age of two certified materials, i.e., U-850 and U-100, which was in good agreement with the reference purification age (61 y). Moreover, the age of a single U-850 particle was determined with a difference of -28 to 2 years from the reference date.

Journal Articles

Katayamazu hot spring

Tomita, Jumpei

Zusetsu Nihon No Onsen No, 170 Onsen No Saiensu, P. 111, 2020/03

no abstracts in English

Journal Articles

Rapid analytical method of $$^{90}$$Sr in urine sample; Rapid separation of Sr by phosphate co-precipitation and extraction chromatography, followed by determination by triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS)

Tomita, Jumpei; Takeuchi, Erina

Applied Radiation and Isotopes, 150, p.103 - 109, 2019/08

 Times Cited Count:6 Percentile:68.11(Chemistry, Inorganic & Nuclear)

A rapid analytical method for determining $$^{90}$$Sr in urine samples (1-2 L) was developed to assess the internal exposure of workers in a radiological emergency. Strontium in a urine sample was rapidly separated by phosphate co-precipitation, followed by extraction chromatography with a tandem column of Pre-filter, TRU and Sr resin, and the $$^{90}$$Sr activity was determined by ICP-MS/MS. Measurement in the MS/MS mode with an O$$_{2}$$ reaction gas flow rate 1 mL min$$^{-1}$$ showed no tailing of $$^{88}$$Sr at m/z = 90 up to 50 mg-Sr L$$^{-1}$$. The interferences of Ge, Se and Zr at m/z = 90 were successfully removed by chemical separation. This analytical method was validated by the results of the analyses of synthetic urine samples (1.2-1.6 L) containing a known amount of $$^{90}$$Sr along with 1 mg of each of Ge, Se, Sr and Zr. The turnaround time for analysis was about 10 h, and the detection limit of $$^{90}$$Sr was approximately 1 Bq per urine sample.

Journal Articles

Recent trend of the radionuclide analyses in bioassay

Tomita, Jumpei

Bunseki, 2019(3), p.112 - 113, 2019/03

no abstracts in English

JAEA Reports

An Analytical method of low-level radium isotopes in freshwater sample by $$gamma$$-ray spectrometry; Application of ${it in situ}$ pre-concentration from large volume of water sample using Powdex resin and barium sulfate coprecipitation of radium isotopes

Tomita, Jumpei; Abe, Takuya

JAEA-Research 2016-026, 12 Pages, 2017/03

JAEA-Research-2016-026.pdf:1.15MB

An analytical method of low-level Ra isotopes in freshwater samples with combination of ${it in situ}$ pre-concentration from large volume of water sample ($$sim$$170 L) using Powdex resin and $$gamma$$-ray spectrometry followed by simple coprecipitation of Ra was developed. ${it In situ}$ pre-concentration of Ra by batch method using Powder resin was examined, and it was shown that the amount of the resin required collecting Ra in the water sample could be determined by measuring the electric conductivity (EC) of water sample. It was found that coprecipitation of Ra with barium sulfate could remove more than 96% of potassium that increases the background. The validation of this method was confirmed by the analyses of 170 L of water sample containing the known amount of Ra isotopes with different EC. Among the analyses, the recovery of Ra was 98% in average and detection limits of $$^{226}$$Ra and $$^{228}$$Ra were achieved to be approximately 0.3 and 0.5 mBq L$$^{-1}$$, respectively.

Journal Articles

Evaluation of $$gamma$$-ray spectra measured inside and outside a house in Fukushima

Tanimura, Yoshihiko; Tomita, Jumpei; Yoshitomi, Hiroshi; Yoshizawa, Michio; Hakozaki, Ryozo*; Takahashi, Sohei*

Hoken Butsuri, 51(3), p.141 - 146, 2016/09

Photon spectra were measured inside and outside a house in Minami-Soma city by using a NaI(Tl) scintillation spectrometer. The photons were categorized into three groups according to their energy. The groups were (1) scattered photons, which include low energy photons, (2) direct photons from $$^{134}$$Cs and $$^{137}$$Cs sources and (3) the other photons. Then the ratios of the ambient dose equivalents H$$^*$$(10) of the scattered photons to those of the direct photons from the $$^{134}$$Cs and $$^{137}$$Cs sources have been evaluated from the measured photon spectra. The ratios are high inside the house compared with those out of the house. It was found that the scattered photons contribute to the H$$^*$$(10) by more than 50$$%$$ inside the house. The ambient dose equivalent average energies of the scattered photons are around 0.25 MeV both inside and outside the house. These data is worthwhile to design the optimum shielding for the protection against the public radiation exposure.

Journal Articles

Determination of low-level radiostrontium, with emphasis on ${it in situ}$ pre-concentration of Sr from large volume of freshwater sample using Powdex resin

Tomita, Jumpei; Yamamoto, Masayoshi*; Nozaki, Teo; Tanimura, Yoshihiko*; Oishi, Tetsuya

Journal of Environmental Radioactivity, 146, p.88 - 93, 2015/08

 Times Cited Count:10 Percentile:38.89(Environmental Sciences)

Journal Articles

Radioactivity and hot springs

Yamamoto, Masayoshi*; Tomita, Jumpei

Onsen Kagaku, 64(4), p.388 - 401, 2015/03

no abstracts in English

Journal Articles

Iodine-129 measurements in soil samples from Dolon village near the Semipalatinsk Nuclear Test Site

Endo, Satoru*; Tomita, Jumpei*; Tanaka, Kenichi*; Yamamoto, Masayoshi*; Fukutani, Satoshi*; Imanaka, Tetsuji*; Sakaguchi, Aya*; Amano, Hikaru; Kawamura, Hidehisa*; Kawamura, Hisao*; et al.

Radiation and Environmental Biophysics, 47(3), p.359 - 365, 2008/07

 Times Cited Count:5 Percentile:23.04(Biology)

Dolon village located about 60 km from the border of the Semipalatinsk Nuclear Test Site is known to be heavily contaminated by the first USSR atomic bomb test in August 1949. Soil samples around Dolon were taken in October 2005 in an attempt to evaluate internal thyroid dose arising from incorporation of radioiodine isotopes (mainly $$^{131}$$I). Iodine-129 in soil was measured by using the technique of Accelerator Mass Spectrometry. From the relationship between $$^{129}$$I and $$^{137}$$Cs (corrected for background and decay from 1949 to 2005) accumulated levels, the background level of $$^{129}$$I and the $$^{129}$$I/$$^{137}$$Cs ratio around Dolon were estimated to be (6.4 $$pm$$0.4) $$times$$ 10$$^{13}$$ atoms m$$^{-2}$$ and 0.25 $$pm$$0.16, respectively. This $$^{129}$$I/$$^{137}$$Cs ratio is almost similar to the fission yield ratio for $$^{239}$$Pu fast fission (0.24).

Oral presentation

An Examination of analysis for $$ ^{90}$$Sr in large water samples

Tomita, Jumpei; Nozaki, Teo; Tanimura, Yoshihiko; Yoshizawa, Michio

no journal, , 

Preconcentration method of Sr with Powdex resin (PCH for cation) at the field was examined to develop the analytical method for $$ ^{90}$$Sr in large water samples, which enables the analysis for a number of samples. In the experiment with 250 L of tap water samples, nearly 100% of Sr in water was adsorbed at 1 g L$$^{-1}$$ of PCH/water ratio, and duplication of boiling with 3M HNO$$_{3}$$ at 0.2 g mL$$^{-1}$$ of PCH/3M HNO$$_{3}$$ allowed the elution of 80% of Sr adsorbed.

Oral presentation

Evaluation of $$gamma$$-ray spectra in living environment around Fukushima Daiichi Nuclear Power Plant

Tanimura, Yoshihiko; Tomita, Jumpei; Yoshitomi, Hiroshi; Yoshizawa, Michio; Hakozaki, Ryozo*; Takahashi, Sohei*

no journal, , 

A easy-to-use $$gamma$$-ray spectrometry technique have been developed using a hand-held NaI(Tl) spectrometer and the MAXED unfolding code. The $$gamma$$-ray spectra in the living environment were measured inside and outside the house at the Minami-Soma city in the Fukushima prefecture. It was found that the dose contribution of the low energy photons is large inside the house compared with those measured outside the house.

Oral presentation

Determination of uranium in urine samples with ICP-MS

Tomita, Jumpei; Nozaki, Teo; Oishi, Tetsuya; Sasa, Yoichi

no journal, , 

no abstracts in English

Oral presentation

An Examination of radium isotope analysis from large volume of freshwater samples

Tomita, Jumpei

no journal, , 

no abstracts in English

Oral presentation

Distribution of anthropogenic and natural radionuclides in well, spring and tap water samples collected from Minamisoma City, Fukushima Prefecture, Japan

Tomita, Jumpei; Abe, Takuya; Sakaguchi, Aya*; Miyata, Yoshiki*; Nagao, Seiya*; Yamamoto, Masayoshi*

no journal, , 

no abstracts in English

Oral presentation

Ra isotopes in fresh groundwater

Tomita, Jumpei; Miyata, Yoshiki*; Hama, Katsuhiro; Sakaguchi, Aya*; Nagao, Seiya*; Yamamoto, Masayoshi*

no journal, , 

no abstracts in English

Oral presentation

Rapid determination of $$^{90}$$Sr in urine samples by extraction chromatography coupled to ICP-MS/MS

Tomita, Jumpei; Takeuchi, Erina

no journal, , 

no abstracts in English

Oral presentation

Rapid determination of Pu in urine sample

Tomita, Jumpei

no journal, , 

no abstracts in English

Oral presentation

24 (Records 1-20 displayed on this page)