Pulsed neutron sources from measurement of nuclear constants

Conclusion The neutron laboratories at Soviet institutes have many kinds of intense sources which make it possible to do a large number of independent measurements of cross sections and constants needed to solve scientific and applied problems. It is important that neutron spectrometers be planned and built in time for specializing in different research areas important to practical applications. This will shorten the time from the appearance of a need for a nuclear constant to completion of the corresponding research.Translated from Atomnaya Énergiya, Vol. 40, No. 4, pp. 318–331, April, 1976. Original article submitted December 2, 1974     

用活化法测量自成靶陶瓷中子管的中子发生率

以自成靶陶瓷中子管内Ｄ、Ｔ离子束流高斯型分布为依据，建立了中子管中子发生率与中子场中某一点通量密度之间的理论联系，采用活化法间接测量得φ６０ｍｍ自成靶陶瓷中子管的中子发生率为２．２×１０＾８／ｓ。     

Eu活化过渡法测量绝对热中子注量率

在相同条件下,以不同时间辐照Ａｕ箔和Ｅｕ箔,用γ谱仪测量＾１９８Ａｕ的４１１ｋｅＶγ射面积和＾１５２Ｅｕ的４１１ｋｅＶγ峰面积,再通过４πβ－γ符合装置测得金箔的绝对中子注量率,根据两者的峰面积之比和测得的Ａｕ箔绝对中子注量率,求得＾１５３Ｅｕ的４１１ｋｅＶγ峰面积对应的中子注量率。     

活化法测量197Au等核素的14MeV中子反应截面

采用活化法测量了197Au等核素的14MeV中子反应截面.当入射中子能量为14.75MeV时,197Au(n,2n)196Au反应截面测量结果为(2175±76)×10-31m2,并与其他测量结果和ENDF/B-6评价数据库数据进行了比较.对于结果的一些不确定度因素,采用MCNP程序进行了分析.     

Fissile material detection by active neutron interrogation with radioactive neutron sources

Different radioactive neutron sources (Am-Li, Am-Be, Cf-252) were considered and tested for active fissile material detection. The low energy Am-Li neutron source has outstanding features. The low dose rate permits full access to the measuring site. The low energy (thermal) neutron flux at the source position is high compared to the high energy neutrons that reach the counter position. In a graphite matrix, of small size, 7 g U-235 led to a doubling of the neutron count rate whereas 200 g graphite changes this count rate by only 2%. The system is in addition operable in the presence of 10¹² Bq of fission products. The detection of fissile material down to 1 g and below has been shown to be possible with this instrument in small samples.     

活化法测量溅射Au原子的各向异性

溅射的空间分布和溅射率的研究不仅是检验各种溅射机制的重要手段而且与许多溅射的应用问题紧密相联。如利用溅射刻绘集成电路所需的复杂图样、单晶表面加工和薄靶制备技术等。此外一些分析技术也有赖于溅射的角分布和能量分布知识。 有关溅射理论的基础是由Sigmund在1969年提出的线性级联碰撞理论。根据他的理论引致的空间溅射角分布是余弦形状的对称分布,但一些实验表明这一理论与实验有明显的偏     

Prediction of the delayed neutron yields for actinide nuclides

Prediction of delayed neutron yields for actinides which are important in the nuclear energy field is given. The prediction is based on a correlation related to a suggested cluster structure of the nucleus.     

用钴活化法测定反应堆中热中子积分通量

本文叙述了用钴活化法测定高通量堆中热中子积分通量的方法。测得的热中子积分通量值与计算值作了比较。本法适于测定在高通量堆中长期辐照的较高热中子积分通量。     

中子活化分析在变质岩原岩类型判别中的应用

应用中子活化分析结合地球化学方法讨论了四川盐边冷水箐的斜长角闪岩和变粒岩的原岩。结果表明,该区的斜长角闪岩是由大洋拉斑玄武岩变质而成,变粒岩则是由酸性沉积岩变质而成。