D-T中子活化实验中89Rb半衰期的实验测量研究

加速器中子活化实验是核专业本科实验教学中的重要实验之一.本文在利用14 MeV快中子辐照238U诱发裂变截面实验过程中引导学生挖掘实验数据,测量了裂变核素(89Rb)的重要核参数—半衰期.本工作运用低本底HPGe-γ谱仪测定裂变产物的一系列γ射线能谱,解谱得到89Rb的特征γ峰计数,从而确定89Rb的半衰期.数据分析中应用89Rb核素两条γ射线分别独立得到89 Rb的半衰期为15.30±0.09 min和15.25±0.07 min.测量结果在与文献数据符合较好的基础上,提高了测量精度.     

地磁对γγ方向角关联测量的影响

在γ-γ角关联实验中,发现能谱中全能峰的位置随探头方位角的改变而变化。本文通过不同的实验,验证了地磁对能谱测量的干扰以及对γ-γ方向角关联测量的影响。发现地磁对测量的影响主要来自光电倍增管,地磁方向与光电倍增管中电子飞行方向的夹角的改变,引起光电倍增管增益变化,最终给γ-γ方向角关联测量带来较大的影响。文中总结了如何减小地磁影响,改进γ-γ方向角关联实验测量的方法。     

Cross-section measurement for Ni（n,x）^58（m＋g）Co, Ni（n, x）^60mCo, Ni（n,x）^61Co and Ni（n,x）^62mCo reactions induced by neutrons around 14 MeV

The cross sections of Ni(n,x)~(58(m g))Co,Ni(n,x)~(60m)Co,Ni(n,x)~(61)Co and Ni(n,x)~(62m)Co reactions induced by neutrons around 14 MeV were measured in this work and calculated by a previously developed formula in this work.The neutron flux was determined using the monitor reaction ~(27)Al(n,α)~(24)Na and the neutron energies were measured with the method of cross-section ratios for ~(90)Zr(n,2n)~(89)Zr to ~(93)Nb(n,2n)~(92m)Nb reactions.     

Excel和Origin在核物理实验“HPGe-γ谱仪效率刻度”中的应用

"HPGe-γ谱仪效率刻度"是核物理实验教学的重要内容。利用Excel对实验数据进行记录和计算,结合Origin软件的数据管理、绘图、微分、非线性拟合等功能,本文给出了效率刻度数据处理方法。对兰州大学核物理实验中心的HPGe-γ探测器进行了效率刻度。本方法大大简化了谱仪效率刻度实验中的数据处理过程。     

Effect of deuteron density distribution on the deduction of screening potential from the D（d,p）T reaction in Be metals

The D(d,p)T reaction in Be metal environments has been measured to investigate the electron screening effect in metals in an energy region of from 5.5 keV to 10 keV in a center of mass system (CMS) at a temperature of 121 K. The depth distribution of deuteron density in Be metals has an impact on the observed reaction yields. A model of deuteron density distribution in metal has been proposed to obtain the original yields. A screening energy of (116±46) eV has been obtained with the assumed deuteron density distribution model.     

基于Multisim12的直接耦合放大电路分析

以一个实际直接耦合放大电路为例,从静态和动态两方面,分析讨论了直接耦合放大电路的分析方法。强调了正确的静态分析在放大电路分析中的重要性。应用Multisim 12.0电路仿真软件对该放大电路进行模拟仿真,并对模拟仿真结果和分析计算结果进行了比较讨论,论证了直接耦合放大电路分析方法的正确性。     

数字电路中“逻辑非”的用法辨析

在数字电子技术的各种资料中，“逻辑非”符号有多种表示形式，其含义容易引起混淆，这严重干扰了学生对数字逻辑电路及逻辑器件知识的理解和应用。就数字逻辑电路中“逻辑非”符号的标注方式和含义进行正确辨析，总结“逻辑非”在不同逻辑电路中的含义及异同，加强数字逻辑电路的教学深度。     

Cross-section measurement for Ni(n,x)58(m+g)Co,Ni(n, x)60mCo, Ni(n,x)61Co and Ni(n,x)62mCo reactions induced by neutrons around 14MeV

The cross sections of Ni(n, x)^58(m+g)Co, Ni(n, x)^60mCo,Ni(n, x)⁶¹Co and Ni(n, x)^62mCo reactions induced by neutrons around 14MeV were measured in this work and calculated by a previously developed formula in this work. The neutron flux was determined using the monitor reaction ²⁷Al(n, α)²⁴Na and the neutron     

金属环境中低能D(d,p)T反应的研究

近年来一系列实验表明， 金属环境中的低能带电粒子引起的核反应截面与气体靶中的相比出现明显增大， 这种现象通常被归结为电子屏蔽效应。 全面介绍了金属环境中D(d, p)T反应电子屏蔽效应的测量方法、 数据分析和实验结果的规律性， 并简要论述了包括德拜等离子体模型在内的各种理论模型对实验结果的解释。 通过研究， 可以获得有关核物理、 核天体物理和凝聚态物理的宝贵知识。 The cross sections σ(E) of low energy nuclear reactions induced by charged particles in metallic environment are much larger than that in gas. Generally, it was taken as the effect of the electron screening. In this work, the experimental method of the D(d, p)T reaction in metallic environment was introduced. The data analysis and the regularity of experimental results were also discussed. All kinds of theoretical models including the Debye model were discussed, which can roughly explain the results of the experiments. The valuable knowledge of nuclear physics, nuclear astrophysics and condensed state physics can be obtained in the study of low energy nuclear reaction in metallic environment.