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Journal Articles

Real time $$alpha$$ value measurement with Feynman-$$alpha$$ method utilizing time series data acquisition on low enriched uranium system

Tonoike, Kotaro; Yamamoto, Toshihiro; Watanabe, Shoichi; Miyoshi, Yoshinori

Journal of Nuclear Science and Technology, 41(2), p.177 - 182, 2004/02

 Times Cited Count:15 Percentile:66.46(Nuclear Science & Technology)

As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function of detector signals and a real time evaluation function of alpha value with the Feynman-$$alpha$$ method was established, with which the kinetic parameter (alpha value) was measured at the STACY heterogeneous core. The Hashimoto's difference filter was implemented in the system, which enables the measurement at a critical condition. The measurement result of the new system agreed with the pulsed neutron method.

JAEA Reports

Characteristics of high repetition rate wavelength tunable solid state laser for real time laser monitoring system

Maruyama, Yoichiro; Kato, Masaaki

JAERI-Research 2002-040, 15 Pages, 2003/02

JAERI-Research-2002-040.pdf:1.05MB

As a tunable laser source for the study of real time LIDAR techique to detect some trace impurities in atmosphere, a dye laser has been employed. As a dye laser is difficult to handle, it is considered that the dye laser may not be used as a practical light source. A tunable solid stat laser composed of an optical parametricc oscillaotr (OPO) which has a wider wavelength range is one of the promising tunable light sources, however, there is no OPO with high repetition rate and large pulse energy. Therefore high repetition rate lasing characteristics of OPO are studied. In this experiment, $$beta$$-Barium Borate (BBO) crystal is utilized as a gain meduim of OPO and pumped by the second harmonic of Nd:YAG laser with the pulse repetition rate of 0.5 kHz. The threshold pumping peak power for BBO-OPO is around 16 MW/cm$$^{2}$$. Maximum OPO average output power of around 5.4 W is obtained with the power conversion efficiency of around 45%. The averege output power of OPO is increasing with the pumping power and undesirable thermal effects are not observed.

Journal Articles

Vanadium uptake and an effect of vanadium treatment on $$^{18}$$F-labeled water movement in a cowpea plant by positron emitting tracer imaging system (PETIS)

Furukawa, Jun*; Yokota, Harumi*; Tanoi, Keitaro*; Ueoka, Shiori*; Matsuhashi, Shimpei; Ishioka, Noriko; Watanabe, Satoshi; Uchida, Hiroshi*; Tsuji, Atsunori*; Ito, Takehito*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 249(2), p.495 - 498, 2001/08

 Times Cited Count:16 Percentile:72.02(Chemistry, Analytical)

We present real time Vanadate (V$$^{5+}$$) uptake imaging in a cowpea plant by Positron Emitting Tracer Imaging System (PETIS). Vanadium-48 was produced by bombarding a Sc foil target with 50 MeV $$alpha$$-particles at Takasaki Ion accelerators for Advanced Radiation Application (TIARA) AVF cyclotron. Then $$^{48}$$V was added to the culture solution to investigate the V distribution in a cowpea plant. The real time uptake of the $$^{48}$$V was monitored by PETIS. We measured the distribution of $$^{48}$$V in a whole plant after 3, 6 and 20 hours of V treatment by Bio-imaging Analyzer System (BAS). After the 20 hour treatment, vanadate was detected at the up-ground part of the plant. To know the effect of V uptake on plant activity, $$^{18}$$F-labeled water uptake was analyzed by PETIS. When a cowpea plant was treated with V for 20 hours before $$^{18}$$F-labeled water uptake experiment, the total amount of $$^{18}$$F-labeled water absorption was drastically desreased. Results suggest the inhibition of water uptake was mainly caused by the vanadate already moved to the up-ground part of the plant.

Journal Articles

$$^{18}$$F used as tracer to study water uptake and transport imaging of a cowpea plant

Nakanishi, Tomoko*; Tanoi, Keitaro*; Yokota, Harumi*; Kang, D.-J.*; Ishii, Ryuichi*; Ishioka, Noriko; Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; Matsuhashi, Shimpei; et al.

Journal of Radioanalytical and Nuclear Chemistry, 249(2), p.503 - 507, 2001/08

We present the water uptake ability of cowpea ($$it {Vigna unguliculata Walp.}$$) which has been regarded as one of the most drought resistant species among the pulse crops. It has been suggested that in the lower part of the stem, parenchymatous tissue for storing water had been developed for the function of deought resistance. We confirmed that in this tissue, water amount was high compared to the other stems by neutron radiography. Then the water uptake manner was measured by positron emitting tracer imaging system (PETIS) using $$^{18}$$F labeled water produced by a cyclotron. Comparing the water uptake manner of cowpea plant with that of common bean, cowpea plant was found to maintain high water uptake activity after drying treatment, suggesting the high drought resistant character.

Journal Articles

Comparison of $$^{15}$$O-labeled and $$^{18}$$F-labeled water uptake in a soybean plant by PETIS (Positron Emitting Tracer Imaging System)

Nakanishi, Tomoko*; Yokota, Harumi*; Tanoi, Keitaro*; Ikeue, Natsuko*; Okuni, Yoko*; Furukawa, Jun*; Ishioka, Noriko; Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; et al.

Radioisotopes, 50(6), p.265 - 269, 2001/06

$$^{15}$$O-Labeled and $$^{18}$$F-Labeled water uptake manner in a soybean plant was compared by PETIS (Positron Emitting Tracer Imaging System). $$^{15}$$O-Labeled water (half-life: 2 min) and $$^{18}$$F-Labeled water (half-life: 110 min) were produced by a cyclotron by $$^{14}$$N(d,n)$$^{15}$$O and $$^{16}$$O($$alpha$$,pn)$$^{18}$$F reactions, respectively. A root of a soybean plant was cut off and each labeled water was supplied from the basal part of the plant. The gamma-rays emitted from the sample was measured by a BGO counter with a detection area of 5 cm$$times$$15 cm. The radioactivity from each stem was accumlated every 15 s till 20 min. It was found that $$^{18}$$F-labeled water was taken up much faster than $$^{15}$$O-labeled water, suggesting that in $$^{18}$$F-labeled water, fluorine was moved in the form of $$^{18}$$F-ion. When BAS image of $$^{15}$$O-labeled water in a plant after 5 min and 10 min of water supply was taken, it was found that the labeled water was observed only in the lowest internode, between a root and the first leaves.

Oral presentation

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