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^152Sm的22—1019keV能区中子俘获截面的测量 总被引:1,自引:0,他引:1
在4.5MeV静电加速器上,利用^7Li(p,n)^7Be和T(p,n)^3He反应作为中子源,在22-1019keV中子能区以^197Au的中子俘获截面为标准,用活化法测量了^152Sm的中子俘获截面,其误差小于6.8%。 相似文献
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长寿命裂变产物核素的热中子反应截面是重要的核参数,它的深入研究和测量不仅对核结构研究有理论意义,而且对放射性废物的分离嬗变、中子活化分析等方面也有应用价值。 相似文献
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简要介绍了热中子俘获发γ射线强度的计算方法,并以实例进行说明,还给出了有关物理自洽检验的方法及其讨论。 相似文献
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超钚核素包括原子序数比钚(Z=94)大的那些元素的各种同位素,即镅及其以上各元素的各种同位素。但目前有中子截面数据的只到~(257)Fm。本评价对~(241)Am直到~(257)Fm的25个核素的热中子截面数据进行了收集、分析和必要的处理,给出了推荐值。数据是按CINDA-A(1935—1976)和CINDA-81(1977—1981.4.1)所列资料目录收集的,凡是 相似文献
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《Journal of Nuclear Science and Technology》2013,50(12):1441-1445
The effective capture cross section of 243Am for thermal neutrons was measured with an activation method. A sample of 243Am was irradiated for 10 hrs at Kyoto University Reactor, KUR. After the irradiation, the sample was cooled for one month. In the cooling time, 244mAm and 244gAm produced by the irradiation decayed out to 244Cm. The α rays emitted from 243Am and 244Cm were measured with a silicon surface barrier detector. The neutron flux at the irradiation position was monitored using Au/Al and Co/Al wires. The effective capture cross section was deduced as 174.5±5.3b from the α-ray counts and the neutron flux. The quantity r√T/T0 in Westcott's convention was 0.037±0.004. The present result was compared with the effective capture cross sections from the JENDL-3.3 and the Mughabghab evaluations. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):546-552
The radioactive nuclides 124Sb (T 1/2=60.3d) and 125Sb (T1/2=2.77yr) were produced from natural antimony by JRR-3 reactor irradiation of 283.5 h through the single and double capture processes. After cooling of 3.50 yr, the γ-ray spectrum of the antimony sample irradiated was measured by a 50 cc coaxial type Ge(Li) detector, and the photo-peak yield ratio of 125Sb (E r=428keV) to 124Sb (E r=1.691 MeV) was obtained. By using a relation between this photo-peak yield ratio and the 124Sb (n, γ) 126Sb cross section, the reactor neutron capture cross section of 60.3-day 124Sb was obtained as 17.4:5:+2.8 ?2.5b. The thermal neutron flux at the position of antimony sample irradiated was estimated as (4.92±0.38) ×1012n/cm2·s by measuring the 1.333-MeV photo-peak yield of 60Co, which was activated by reactor irradiation of cobalt impurity contained in the antimony sample. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):460-468
The neutron capture cross section of 237Np has been measured for fast neutrons supplied at the center of the core in the Yayoi reactor. The activation method was used for the measurement, in which the amount of the product 238Np was determined by γ-ray spectroscopy using a Ge detector. The neutron flux at the center of the core calculated by the Monte Carlo simulation code MCNP was renormalized by using the activity of a gold activation foil irradiated simultaneously. The new convention is proposed in this paper to make possible a definite comparison of the integral measurement by the activation method using fast reactor neutrons with differential measurements using accelerator-based neutrons. “Representative neutron energy” is defined in the convention at which the cross section deduced by the activation measurement has a high sensitivity. The capture cross section of 237Np corresponding to the representative neutron energy was deduced as 0:80 ± 0:04b at 214 ± 9 keV from the measured reaction rate and the energy dependence of the cross section in the nuclear data library ENDF/B-VII.0. The deduced cross section of 237Np at the representative neutron energy agrees with the evaluated data of ENDF/B-VII.0, but is 15% higher than that of JENDL-3.3 and 13% higher than that of JENDL/AC-2008. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(7):447-456
The neutron capture cross section of praseodymium (141Pr) has been measured relative to the 10B(n,αγ) standard cross section in the energy region from 0.003 eV to 140 keV by the neutron time-of-flight (TOF) method with a 46-MeV electron linear accelerator (linac) of the Research Reactor Institute, Kyoto University (KURRI). An assembly of Bi4Ge3O12 (BGO) scintillators was used for the capture cross section measurement. In addition, the thermal neutron cross section (2,200 m/s value) of the 141Pr(n, γ)142Pr reaction has been also measured by an activation method at the heavy water thermal neutron facility of the Kyoto University Reactor (KUR). The thermal neutron flux was monitored with the 197Au(n, γ)198Au standard cross section. The above TOF measurement has been normalized to the current activation data (11.6±1.3 b) at 0.0253 eV. The evaluated data in JENDL-3.3, ENDF/B-VI, and JEF-2.2 have been in general agreement with the current result, except that the JENDL-3.3 and the JEF-2.2 values are clearly lower than the measurement in the cross section minimum region from about 10 to 500 eV. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(11):1289-1297
In order to determine the thermal neutron capture cross section of 237Np, the relevant γ emission probabilities of the 312-keV γ-ray from the decay of 233Pa and the 984-keV γ-ray from the decay of 238Np are deduced from the ratio of the emission rate to the activity. The emission rate and activity are measured with a Ge detector and a Si detector, respectively. The measured emission probability for 312-keV γ-ray is 41.6±0.9% and that for 984-keV γ-ray is 25.2±0.5%. The emission probabilities are used to correct the thermal neutron capture cross section of 237Np reported previously, and gives 168±6b. The neutron capture cross section is also determined as 169±6b by α-ray spectroscopic method. The measured emission probabilities and capture cross section are compared with others from references. By averaging these values deduced by different methods, the value of 169±4b is recommended as the thermal neutron capture cross section of 237Np for 2,200 m/s neutrons. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(12):1500-1508
The thermal-neutron capture cross section (σ0;g) and the resonance integral (I 0,g) leading to the ground state of 242Am were measured by an activation method for neutron capture by241 Am. A method with gadolinium, which was similar to the cadmium difference method, was used to measure the cross section σ0;g with attention to resonances of241 Am. Americium chloride samples containing241 Am radioisotope were irradiated for 68 h in the long-irradiation plug of the Kyoto University Research Reactor, KUR. Wires of Co/Al and Au/Al alloys were used as monitors to determine thermal-neutron fluxes and epithermal Westcott's indexes at the irradiation positions. An α-ray spectrometer was used to measure the activity ratios of242 Cm to241 Am. On the basis of Westcott's convention, the σ0;g and I 0,g values were determined as 628 ± 22 b and 3:5 ± 0:3 kb, respectively. 相似文献