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1.
Using animals a study on the internal contamination by U ingestion is presented. Two rats of Wistar-London breed were contaminated at once and after different time intervals, 3 days and 10 days respectively, they were sacrified. Uranium biodistribution in the vital organs as well as the uranium retention and elimination was investigated using the fission track method. For the two contaminated subjects a comparison between obtained quantitative results is given.  相似文献   

2.
Measurements of the reaction rate distribution were carried out using two kinds of Plate Micro Fission Chamber (PMFC). The first is a depleted uranium chamber and the second an enriched uranium chamber. The material in the depleted uranium chamber is strictly the same as the material in the uranium assembly. With the equation solution to conduct the isotope contribution correction, the fission rate of 238U and 235U were obtained from the fission rate of depleted uranium and enriched uranium. Then, the fission count of 238U and 235U in an individual uranium shell was obtained. In this work, MCNP5 and continuous energy cross sections ENDF/BV.0 were used for the analysis of fission rate distribution and fission count. The calculated results were compared with the experimental ones. The calculation of fission rate of DU and EU were found to agree with the measured ones within 10% except at the positions in polyethylene region and the two positions near the outer surface. Because the fission chamber was not considered in the calculation of the fission counts of 238U and 235U, the calculated results did not agree well with the experimental ones.  相似文献   

3.
The improved version of Los Alamos model with the multi-modal fission approach is used to analyse the prompt fission neutron spectrum and multiplicity for the neutron-induced fission of 237Np. The spectra of neutrons emitted from fragments for the three most dominant fission modes (standard Ⅰ, standard Ⅱ and superlong) are calculated separately and the total spectrum is synthesized. The multi-modal parameters contained in the spectrum model are determined on the basis of experimental data of fission fragment mass distributions. The calculated total prompt fission neutron spectrum and multiplicity are better agreement with the experimental data than those obtained from the conventional treatment of the Los Alamos model.  相似文献   

4.
The fission probabilities and angular distributions of the fission fragments for the (α, α'f) reaction on 232Th and 238U at a bombarding energy of 120 MeV have been measured from about 4 to 14 MeV excitation energy. Evidence for sub-barrier resonances has been found, the negativeparity ones occurring at the same excitation energy where photofission resonances have been observed. The data are analyzed with the two-humped barrier model. For 238U the data are reasonably well fitted with barriers similar to those known from the literature. For 232Th though, the outer barrier parameters are quite different: the height EB = 6.6 MeV and the width (khω)B = 1.2 MeV. Also for 232Th, introducing an additional mass symmetric and axially asymmetric outer barrier, as was previously found necessary for 238U, does not result in a good fit to the data at higher excitation energies.  相似文献   

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6.
言杰  李澄  刘荣  蒋励  鹿心鑫  王玫 《物理学报》2011,60(3):32901-032901
本文利用252Cf快裂变室和多参数数据采集系统,逐事例的同时记录了自发裂变中子和瞬发伽马的飞行时间(TOF),脉冲形状甄别(PSD)和反冲能量(RE,裂变中子是通过测量反冲质子;瞬发伽马是通过测量康普顿反冲电子)三维信息.详细介绍了通过离线数据分析完全扣除三维信息中的伽马事例贡献,以获得Φ50.8 mm×50.8 mm的BC501A液闪探测器的相对探测效率和响应函数的方法.在不通过探测器响应函数进行数据转换的条件下,利用中子的能量直接确定了中子的有效测量阈值.得到的中子 关键词: 252Cf快裂变室')" href="#">252Cf快裂变室 BC501A液闪探测器 相对探测效率 响应函数  相似文献   

7.
The postulates of the double core model of binary fission are examined against the two well-known charge division mechanisms of fission, namelyucd andecd. An analytic expression of the modifieducd formula is obtained. Radiochemical distribution of mass and charge, formulated from the model, is found to agree satisfactorily with available experimental results. Finally, the most probable charge and mass values of the radiochemical heavy and light products, the average number of neutron andβ-emissions per fragment, are calculated, and found to agree with experimental observations.  相似文献   

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