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Volume 38, Issue 3
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[in Japanese], Bernard L. COHEN1996 Volume 38 Issue 3 Pages 178-183
Published: March 30, 1996
Released on J-STAGE: April 21, 2009
JOURNAL FREE ACCESSDownload PDF (3550K) -
1996 Volume 38 Issue 3 Pages 184-204
Published: March 30, 1996
Released on J-STAGE: January 08, 2010
JOURNAL FREE ACCESS -
Masaki MORISHITA, Kunihiro ITOH, Tsuguyuki KOBAYASHI, Toshihiko HORIUC ...1996 Volume 38 Issue 3 Pages 205-210
Published: March 30, 1996
Released on J-STAGE: April 21, 2009
JOURNAL FREE ACCESS -
Mitsuru UESAKA, Takahiro KOZAWA, Toshiaki KOBAYASHI, Toru UEDA, Kenzo ...1996 Volume 38 Issue 3 Pages 219-229
Published: March 30, 1996
Released on J-STAGE: April 21, 2009
JOURNAL FREE ACCESSUltrafast and basic processes of interaction of radiation with matter, such as excitation, relaxation, vibration and ionization of atoms and molecules, and radiation damage, occur in a femtosecond time domain. Aimimg at investigation of such phenomena, a subpicosecond (0.5-0.9ps) 37MeV electron single bunch was generated at the S-band linear accelerator of Nuclear Engineering Research Laboratory, University of Tokyo. An original single bunch with a pulse width [full width at half maximum (FWHM)] of about 10ps was successfully compressed to a subpicosecond time domain by magnetic pulse compression. The magnetic pulse compression using the nonlinear energy modulation was developed to achieve the most effective compression. Then an achromatic magnetic pulse compressor was constructed to focus the beam spot and increase the charge density. Furthermore, the operation mode of the 90keV thermionic electron gun was optimized to enhance a brightness of the subpicosecond single bunch. Finally, a 900fs single bunch containing 1.0nC per bunch was achieved. Subpicosecond pulse-radiolysis experiments are under way by using the subpicosecond electron single bunch. Further, we have proposed and designed a femtosecond quantum phenomena research facility to investigate ultrafaster phenomena in radiation physics, chemistry, material science and electromagnetics.View full abstractDownload PDF (3702K) -
Yoko SHIMADA, Shinsuke MORISAWA, Yoriteru INOUE1996 Volume 38 Issue 3 Pages 230-239
Published: March 30, 1996
Released on J-STAGE: March 08, 2010
JOURNAL FREE ACCESSThe pathway of farm product intake are very important for evaluating the human health risks caused by the long term global radioactive contamination. The main parameters contained in this pathway: the distribution coefficient (kd), the transfer coefficient by direct foliar absorption (K) and the transfer coefficient by root uptake (TF), were determined using the Sr-90 and Cs-137 environmental monitoring data in Japan. The major finding obtained in this study are as follows:
(1) kd can be determined by the monitoring data of radionuclide concentration in soil, K by the concentration in farm products during larger fallout period, 1960's, and TF by the concentration in farm products during smaller fallout period, after 1970's.
(2) The ranges of kd were determined as 10-300 for Sr-90 and 10-2, 000 (ml/g) for Cs-137. These ranges are smaller than the reported ranges, thus the accuracy for estimating kd were improved in this study. K are 0.03 -1 for Sr-90 and 0.4-1(cmcm2·month/g) for Cs-137; TF are 0.001-0.06 for Sr-90 and 0.0005-0.001 (-) for Cs-137.View full abstractDownload PDF (13686K)
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