RADIOISOTOPES

A New Method for Ion Collection System Using Magnetic Levitation Electrode

Toshiro KAWAGUCHI, Atushi YOSHIMURA

1999Volume 48Issue 1 Pages 1-11
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.1

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Current-voltage characteristics of a new-type ionization chamber made by a levitated battery and electrodes was measured. The electrode to be supplied with electric voltage and a battery levitates into air, and the electrode to collect ions are supported on a base by insulators, and connected to an ammeter. Potential is induced between the high-voltage electrodes levitated and a charge-collecting electrode grounded, so that ions due to rariations are collected on the charge-collecting electrode. In this method, there is no leakage current flowing from the high-voltage electrodes to the charge-collecting electrode and ammeter. Therefore, even under the condition of high humidity, it is possible to measure the ionization current continuously with high sensitivity. In the experimental results, current-voltage characteristics of this new-type ionization chamber agree well with those of the conventional ionization chamber. In addition, together with stable ionization current shown in an atmosphere with high humidity, it has been possible to measure variations of ionization current due to those of humidity.

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Effects of Gamma Irradiation of an Isolated Flower in Reproductive Stages on Seed Production of Brassica napus L.

Harufumi MINAMI, Noboru SAKURAI, Takeo MUROYAMA, Daisuke HOGETSU

1999Volume 48Issue 1 Pages 12-16
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.12

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We examined seed production after gamma irradiation of an isolated whole flower (a flower with pedicel) of Brassica napus strain 1 through a flower organ culture and estimated the effects of gamma rays on embryogenesis in sexual reproductive stages. The whole flowers were irradiated with 17, 32, 57 and 87 Gy of gamma rays in unpollinated stage at day of anthesis, in stage shortly after fertilization and early embryo stage. The gamma irradiation of flowers in stage shortly after fertilization showed a drastic effect on the mature seed production. The number of seeds per pod began to decrease at 17Gy and dropped to 15% of that of unirradiated flowers at 32 Gy. On the other hand, the flowers irradiated in the unpollinated and early embryo stages began to reduce the number of seeds at 57 Gy. The ovary elongation were suppressed with increasing irradiation dose when the flower was irradiated in unpollinated stage and stage shortly after fertilization.

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Uptake and Metabolism of NaH³⁵SO₃ in Rice and Barley Seedlings

Nobuyuki SHIOMI

1999Volume 48Issue 1 Pages 17-22
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.17

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Comparative laboratory experiments regarding the effects of NaHSO₃ on growth and the incorporation of NaH³⁵SO₃ into rice and barley seedlings were examined. Both rice and barley seedlings showed much lower growth above 10^-3M (=mol/1) concentration of NaHSO₃ in the medium, than the control. The reduced ratio to the control was higher in barley than in rice.
Total incorporation of NaH³⁵SO₃ declined with an increase of NaHSO₃ during culture. Rice incorporated NaH³⁵SO₃ into the tissues much more than barley at late phase of culture and pooled it as an inorganic form without translocation to organic metabolites. However in barley, the fixation of NaH³⁵SO₃ in the ethanol insoluble and cationic fraction increased remarkably during culture. In the two plant tissues at 10^-3 M, the ³⁵S distribution into sulfur amino acids in the cationic fraction was lower than that of control. More than 80% of the radioactivity was occupied by sulfur amino acids in the protein hydrolysates similarly in rice and barley.

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A Calibration Technique by Pulse-like Injection of Radioactive Gases for Gas Monitors

Tetsuya OISHI, Makoto YOSHIDA

1999Volume 48Issue 1 Pages 23-31
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.23

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A calibration technique of wide use for gas monitors by pulse-like injection of radioactive gases was studied. It is based on the time analysis of the monitor output which is measured by injecting a known amount of radioactive gas in a short time interval. As a result, it leads to the direct evaluation of the gaseous activities flowing into the gas monitor.
This technique enables the estimation of accurate activities in the cases of the release of radioactive gases in a short duration from nuclear facilities and the sudden change of gas concentrations.

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Transmission of the Environmental Radiation Data Files on the Internet

Yoshiaki YAMAGUCHI, Atsushi MATSUMOTO, Bunkei KYOH, Tadashi SAITO, Tak ...

1999Volume 48Issue 1 Pages 32-36
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.32

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Recently, any text or data file has come to be transportable through the Internet with a personal computer. It is, however, restricted by selection of monitoring point to lay the cable because the personal circuit is generally used in case of continuous type environmental monitors.
This is the reason why we have developed an environmental monitoring system that can transmit radiation data files on the Internet. Both 3“φ×3” NaI (Tl) detector and Thermo-Hydrometer are installed in the monitoring post of this system, and the data files of those detectors are transmitted from a personal computer at the monitoring point to Radioisotope Resarch Center of Osaka Univirsity.
Environmental monitoring data from remote places have easily been obtained due to the data, transmission through the Internet. Moreover, the system brings a higher precision of the environmental monitoring data because it includes the energy information of r-rays. If it is possible to maintain the monitors at remote places, this system could execute the continuous environmental monitoring over the wide area.

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Application of Positron Emitting Tracer Imaging System (PETIS) for Plant Research

Tamikazu KUME

1999Volume 48Issue 1 Pages 37-47
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.37

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3. FAQs of BAS (Frequently Asked Questions of Bio-imaging Analyzer Systems)

Keiji MORI

1999Volume 48Issue 1 Pages 48-62
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.48

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IV. Study on Physical Property by Synchrotron Radiation

9. Materials Structure Research by Synchrotron X-Ray Diffraction

Youichi MURAKAMI

1999Volume 48Issue 1 Pages 63-71
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.63

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[title in Japanese]

[in Japanese]

1999Volume 48Issue 1 Pages 73-74
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.73

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[title in Japanese]

[in Japanese], [in Japanese]

1999Volume 48Issue 1 Pages 75-76
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.75

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[title in Japanese]

[in Japanese]

1999Volume 48Issue 1 Pages 77-78
Published: January 15, 1999
Released on J-STAGE: March 10, 2011

DOIhttps://doi.org/10.3769/radioisotopes.48.77

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