巻号一覧
1 巻, 3 号
選択された号の論文の5件中1～5を表示しています
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Time-Dependent Thermal Neutron Angular Flux from a Pulsed Exponential Assembly Calculated in P3-Approximation of the Transport EquationHisashi HISHIDA, Tamotsu SEKIYA, Tokuo SUITA1964 年 1 巻 3 号 p. 79-86
発行日: 1964年
公開日: 2008/02/28
ジャーナル フリーIn order to discuss the ambiguity inherent in the diffusion approximation applied to a small-sized medium including a pulsed neutron source, the time variation and the spatial distribution of thermal neutron angular flux are calculated in P3-approximation of the time-dependent Boltzmann transport equation. With the discussion on the existence of a set of real and complex eigenvalues, the real eigenvalues for the lowest and some higher modes are computed numerically and the corresponding eigenfunctions are derived under Marshak's boundary condition. The results are compared with those obtained in the diffusion approximation and the physical interpretations of resultant asymptotic and non-asymptotic thermal neutron flux are given.抄録全体を表示PDF形式でダウンロード (536K) -
Iwao UMEDA1964 年 1 巻 3 号 p. 87-92
発行日: 1964年
公開日: 2008/02/28
ジャーナル フリーFor the case of point isotropic source, the number and energy current build-up factors, number of collisions, energy current spectra of γ-rays transmitted through spherical and cylindrical shields, and angular distribution through spherical shields were obtained by Monte Carlo calculations. adiation with energy of 1.25 and 0.662 MeV was assumed to be emitted from the center of an iron and a lead shield varying from 1 to 5 mean free paths in radius. The case histories of 2, 000 photons for a spherical shield and 4, 000 photons for a cylindrical shield were followed on the IBM 7070 digital computer. Further, a 60Co point isotropic source was placed at the center of a cylindrical plastic scintillator, and pulse height distribution caused by energy absorption was measured for comparison with the Monte Carlo values. The results obtained by the experiment showed good agreement with the results of the Monte Carlo calculation.抄録全体を表示PDF形式でダウンロード (362K) -
Tadashi KUBOTA, Yoshinobu SEKI, Shuichiro TAKAHASHI1964 年 1 巻 3 号 p. 93-100
発行日: 1964年
公開日: 2008/02/28
ジャーナル フリーThermal conductivities of UO2, UC and UC2 were measured with apparatuses developed by the authors. Main results obtained were as follows:
(1) There was no clear evidence of the increase of thermal conductivity of UO2 in the temperature range between 1, 000 ?? and 1, 600 ??, although the effect of radiation transfer mechanism was thought to play a role from the tendency that the decrease of thermal conductivity did cease around 1, 200 ?? .
(2) Thermal conductivities of sintered UC and UC2 pellet-both 95%T.D.-were measured by axial heat flow method. Thermal conductivity of UC was around 0.05-0.04 cal/sec•cm• ?? At the temperature range between 100°and 400°C, while measured values on UC2 were around 0.016-0.014 in the temperature range between 200 ?? And 400 ?? .抄録全体を表示PDF形式でダウンロード (579K) -
Eiji SAKAI, Hiroyuki TAMURA, Yoshifumi SAKURAI SAKURAI1964 年 1 巻 3 号 p. 101-109
発行日: 1964年
公開日: 2008/02/28
ジャーナル フリーLow geometry α counting and α-particle/γ-ray coincidence counting were made to determine the absolute disintegration rate of an 241Am source.
Alpha particles were counted by silicon junction detectors and γ-rays by an NaI (T1) crystal-photomultiplier system. The half life of the 60 keV level of 237Np was measured to check the effect of the coincidence resolving time in the absolute measurement of the americium source by α-γ coin-cidence counting; the half life measured was 6.3×10-8 sec.
The mean value of the absolute disintegration rate of a typical 241Am source measured by coin-cidence counting was 1.696×104 dps and the 90% confidence interval for the mean value was [1.679 ×104 dps, 1.713×l04 dps]. Accurate absolute measurements by low geometry a particle counting are very difficult especially for very small semiconductor detectors because of the difficulty of measuring the accurate geometries.抄録全体を表示PDF形式でダウンロード (434K) -
Toru HIRAOKA, Tsutomu IIJIMA, Naohiro HIRAKAWA, Tomoo NAKAMURA, Masao ...1964 年 1 巻 3 号 p. 108-109
発行日: 1964年
公開日: 2008/02/28
ジャーナル フリーPDF形式でダウンロード (121K)
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