Calculation of Neutron-Proton Mass Difference by the Monte Carlo Method

Calculation results of the Monte Carlo method of the average energy of the electrostatic interaction between the quarks are presented to the neutron and proton. The proposed model of the distribution of quarks in protons and neutrons is possible to assess the area which included a strong (gluon) interaction. Given the fact that the probability of finding a quark in the field with strong interaction is less than one, there is a good agreement between the experimental and calculated values of the mass difference between the neutron and the proton.

Probing neutron–proton effective mass splitting using nuclear stopping and isospin mix in heavy-ion collisions in GeV energy region

The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.

Predicting the Neutron and Proton Masses Based on Baryons which Are Yang-Mills Magnetic Monopoles and Koide Mass Triplets

We show how the Koide relationships and associated triplet mass matrices can be generalized to derive the observed sum of the free neutron and proton rest masses in terms of the up and down current quark masses and the Fermi vev to six parts in 10,000. This sum can then be solved for the separate neutron and proton masses using the neutron minus proton mass difference derived by the author in a recent, separate paper. The oppositely-signed charges of the up and down quarks are responsible for the appearance of a complex phase exp(iδ) and real rotation angle θ which leads on an independent basis to mass and mixing matrices similar to that of Cabibbo, Kobayashi and Maskawa (CKM). These can then be used to specify the neutron and proton mass relationships to unlimited accuracy using θ as a nucleon fitting angle deduced from empirical data. This fitting angle is then shown to be related to an invariant of the CKM mixing angles within experimental errors. Also developed is a master mass and mixing matrix which may help to interconnect all baryon and quark masses and mixing angles. The Koide generalizations developed here enable these neutron and proton mass relationships to be given a Lagrangian formulation based on neutron and proton field strength tensors that contain vacuum-amplified and current quark wavefunctions and masses. In the course of development, we also uncover new Koide relationships for the neutrinos, the up quarks, and the down quarks.

Isospin dependence of nucleon effective masses in neutron-rich matter

In this talk,we first briefly review the isospin dependence of the total nucleon effective mass M Jinferred from analyzing nucleon-nucleus scattering data within an isospin-dependent non-relativistic optical potential model,and the isospin dependence of the nucleon E-mass M;E J obtained from applying the Migdal–Luttinger theorem to a phenomenological single-nucleon momentum distribution in nuclei constrained by recent electron-nucleus scatteringexperiments.Combining information about the isospin dependence of both the nucleon total effective mass and E-mass,we then infer the isospin dependence of nucleon k-mass using the well-known relation M_J~*=M_ J^(*1E).Implications of the results on the nucleon mean free path in neutron-rich matter are discussed.

Third-Order Corrections and Mass-Shedding Limit of Rotating Neutron Stars Computed By a Complex-Plane Strategy

We implement the so-called “complex-plane strategy” for computing general-relativistic polytropic models of uniformly rotating neutron stars. This method manages the problem by performing all numerical integrations, required within the framework of Hartle’s perturbation method, in the complex plane. We give emphasis on computing corrections up to third order in the angular velocity, and the mass-shedding limit. We also compute the angular momentum, moment of inertia, rotational kinetic energy, and gravitational potential energy of the models considered.

百千瓦级空间核反应堆屏蔽优化研究

屏蔽体尺寸和重量对空间核反应堆和核动力航天器性能有着重要影响,因而屏蔽设计优化是空间核动力系统设计的关键。本文以JIMO项目反应堆为对象,在铍-碳化硼-钨-氢化锂分层组合屏蔽方案的基础上,考虑到辐照剂量的径向分布,采用蒙特卡罗方法计算了负载处辐照剂量和氢化锂中子剂量,分析了屏蔽设计原理,并提出了分步优化方法以实现屏蔽优化。根据结果分析,调整了铍和碳化硼的厚度比例、钨半径及布置位置,获得了优化的屏蔽方案,在满足屏蔽要求的基础上质量减少了98.41 kg。提出的屏蔽方案及设计流程可为空间核电源屏蔽设计优化提供参考。

Neutron stars:a relativistic study

We study the inner structure of a neutron star from a theoretical point of view and the outcome results are compared with observed data. We propose a stiff equation of state relating pressure with matter density. From our study we calculate mass（M）,compactness（u） and surface redshift（Zs） for two binary millisecond pulsars,namely PSR J1614–2230 and PSR J1903＋327,and four X-ray binaries,namely Cen X-3,SMC X-1,Vela X-1 and Her X-1,and compare them with recent observational data.Finally,we examine the stability for such a type of theoretical structure.

Modification of Even-A Nuclear Mass Formula

In this paper we obtain an empirical mass formula of even-A nuclei based on residual proton-neutron interactions. The root-mean-squared deviation (RMSD) from experimental data is at an accuracy of about 150 Kev. While for heavy nuclei, we give another formula that fits the experimental data better (RMSD ≈ 119 Kev). We have successfully described the experimental data of nuclear masses and predicted some unknown masses (like 200Ir not involved in AME2003, the deviation of our predicted masses from the value in AME2012 is only about 82 keV). The predictive power of our formula is more competitive than other mass models.

The Effective Chiral Model of Quantum Hadrodynamics Applied to Nuclear Matter and Neutron Stars

We review theoretical relations between macroscopic properties of neutron stars and microscopic quantities of nuclear matter, such as consistency of hadronic nuclear models and observed masses of neutron stars. The relativistic hadronic field theory, quantum hadrodynamics (QHD), and mean-field approximations of the theory are applied to saturation properties of symmetric nuclear and neutron matter. The equivalence between mean-field approximations and Hartree approximation is emphasized in terms of renormalized effective masses and effective coupling constants of hadrons. This is important to prove that the direct application of mean-field (Hartree) approximation to nuclear and neutron matter is inadequate to examine physical observables. The equations of state (EOS), binding energies of nuclear matter, self-consistency of nuclear matter, are reviewed, and the result of chiral Hartree-Fock ?approximation is shown. Neutron stars and history of nuclear astrophysics, nuclear model and nuclear matter, possibility of hadron and hadron-quark neutron stars are briefly reviewed. The hadronic models are very useful and practical for understanding astrophysical phenomena, nuclear matter and radiation phenomena of nuclei.

Mass-to-Energy Conversion, the Astrophysical Mechanism

A new interpretation of the relativistic equation relating total-, momentum-, and mass-energies is presented. With the aid of the familiar energy-relationship triangle, old and new interpretations are compared. And the key difference is emphasized—apparent relativity versus intrinsic relativity. Mass-to-energy conversion is then brought about by adopting a three-part strategy: 1) Make the motion relative to the universal space medium. This allows the introduction of the concept of intrinsic energy (total, kinetic, and mass energies) as counterpart to the apparent version. 2) Recognize that a particle’s mass property diminishes with increase in speed. This means introducing the concept of intrinsic mass (which varies with intrinsic speed). 3) Impose a change in the particle’s gravitational environment. Instead of applying an electromagnetic accelerating force or energy in order to alter the particle’s total energy, there will simply be an environmental change. Thus, it is shown how to use relativity equations and relativistic motion—in a way that exploits the distinction between apparent and innate levels of reality—to explain the mass-to-energy-conversion mechanism. Moreover, the mechanism explains the 100-percent conversion of mass to energy;which, in turn, leads to an explanation of the mechanism driving astrophysical jets.

Computing Differentially Rotating Neutron Stars Obeying Realistic Equations of State by Using Hartle’s Perturbation Method

In this paper, we use the well-known Hartle’s perturbation method in order to compute models of differentially rotating neutron stars obeying realistic equations of state. In our numerical treatment, we keep terms up to third order in the angular velocity. We present indicative numerical results for models satisfying a particular differential rotation law. We emphasize on computing the change in mass owing to this differential rotation law.

A Study of Neutron and Gamma-Ray Interaction Properties with Cobalt-Free Highly Chromium Maraging Steel

Cobalt-free maraging steels of different compositions have been prepared by electro-slag remelting technique using titanium and chromium instead of cobalt. Neutron removal cross-sections have been calculated, also mass attenuation coefficients and effective electron densities have been determined for the prepared samples in the photon energy range up to 2.8 MeV. Other steel alloys and lead samples have also been investigated for the sake of comparison. The results prove the superiority of cobalt-free maraging steels compared with the other steel types to be used as a proper shielding material in the nuclear field. Among the investigated steels, the steel “0.045%C- 13.35%Ni-2.05%Cr-4.5%Mo-0.06%Ti” has the best attenuation properties.

变化吸积率下中子星的壳冷却研究

暂现源中子星(NS)低质量X射线双星为研究NS壳加热和冷却提供了一个宝贵的机会.模拟其宁静期的光变曲线需要在中子星的浅壳层加一个额外的未知热源.通过开源的dStar程序,探究时间依赖吸积率对中子星壳冷却以及浅壳层加热参数的影响.研究表明:爆发初期变化吸积率对壳冷却影响较小,爆发期最后阶段吸积率的变化对壳冷却有较大的影响.变化吸积率导致爆发结束后中子星表面的温度比常数吸积率下中子星表面温度低,因此变化吸积率下需要提供更多的浅壳层加热来拟合爆发结束后的壳冷却观测.研究了MXB 1659-29和MAXI J0556-332这两颗源,它们对应不同的吸积时间以及浅壳层加热,时间变化吸积率对这两颗源的壳冷却以及浅壳层加热参数的影响是一致的.

铀材料的中子多重性测量分析方法

多重性测量是一种可以显著提高测量精度、降低测量偏倚的新方法。本文分析了主动法符合测量偏倚较大的原因,介绍了主动法多重性测量的理论关系式,阐述了由测量数据先确定样品增殖,再由经验关系式得到反应系数,进而得到样品质量的数据处理方法。

加速器质谱法测定环境和生物样品中的^(129)I

建立了环境和生物样品中的129I的分析方法,采用碱式灰化、萃取反萃、沉淀等步骤对环境和生物样品中的碘进行预浓集,用131I[NaI]为放射性示踪剂优化各分步的制备条件,运用加速器质谱法测定了北京地区松针和干草、青岛地区海藻和海水中的129I/127I。用超热中子活化法测定样品中的稳定碘(即127I)含量。上述松针、干草、海藻和海水样品中的129I/127I分别为8.11×10-9、5.97×10-9、1.70×10-10和6.05×10-10;相应的129I浓度分别为3.22×10-15、1.24×10-14、1.27×10-14g/g干重和2.30×10-14g/L。与文献报道值相比,我国与国外同类地区相当甚至更低,比法国和英国乏核燃料后处理厂附近环境中的129I低2～3个数量级,表明我国这些非核设施影响地区的129I处于当今全球环境的本底放射性沉降水平。

中子多重性钚-铀部件质量测量系统及实验进展

为了对核弹头中拆卸下来的和处于库房存储状态的核部件的质量进行无损测量,搭建了一个由32根3 He正比计数管和方型高密度聚乙烯慢化腔体构成的中子多重性探测器,采用8通道电子学处理器件进行中子脉冲信号分析,基于5组252 Cf中子源对中子多重性探测器进行标定,验证了自主开发的标定算法,获取了系统标定参数。分别对6个武器级罐装钚部件,7个罐装铀部件进行中子多重性实验测量,实验分析结果显示:基于点模型修正后的钚部件中子多重性质量测量值与标称值偏差小于1.5%,基于双Am-Li源标定曲线法的铀部件质量测量偏差小于5%。

不同水温下的中子输运等效质量热运动模型

为了解决蒙特卡罗模拟S(α,β)模型只能求解特定温度条件下中子输运问题的局限性,建立了中子在不同温度液态水中输运的等效质量热运动模型。在分析自由气体热运动模型的基础上,采用不同的等效质量对中子与水中氢原子的弹性散射模拟过程进行改进,对中子穿过水层后的流量进行模拟计算,通过与S(α,β)模型的计算结果的比较,得到了5个不同的温度点水中氢原子的最佳等效质量。根据5个不同温度点的数据拟合给出了最佳等效质量和温度的函数关系。采用该模型计算得到的中子在不同温度条件下水中输运参数与S(α,β)模型相符。等效质量热运动模型突破了S(α,β)模型只能计算有限温度点的局限性,能有效处理300～800 K任意温度水中的中子输运问题。

Rossi－α方法在微型堆上的应用

利用Ｒｏｓｓｉ－α方法测量不同装载下的瞬发中子衰减常数α，求得装载量与α的数学表达式。利用该数学式和临界时的瞬发中子衰减常数求得的临界质量；与外推方法得到的临界质量相符。该方法适用于临界安全分析和对临界实验结果的校核。

大空腔探测系统中子多重性随机模拟及参数计算

为优化中子多重性探测器设计、指导多重性实验的正确实施,论述了利用蒙特卡罗程序获取中子时间脉冲序列链进行多重性随机模拟的方法。提出了一种新的三均分算法计算中子衰减时间常数,解决了生成时间序列链超大矩阵排序问题。基于大空腔探测系统,利用无死时间的时间序列链经过数据解谱,分析利用252 Cf中子源标定的参数在钚样品多重性测量过程中的匹配问题,考察了探测效率的差异和二阶矩三阶矩的门份额的适用性,并提出了移位寄存器(MSR)处理过程中门宽的优化选取原则。模拟了大量不同质量的钚样品,建立了大空腔探测系统的质量相对标准偏差(RSD)曲线。结果表明:252 Cf源标定的探测效率比Pu样品的效率差3%左右,比值法与公式法计算的门份额完全一致,大空腔探测系统对公斤级的金属钚在1000s时间内的质量测量RSD约为4%。

引入源-样品距离影响的主动中子多重性质量反演公式

主动中子多重性计数测量方法是常用的核材料质量无损测量方法,已广泛应用于核材料衡算、核安保测量与军控核查等领域。我们通过对JMCT中子-光子输运程序的二次开发,实现了对经典点模型铀样品质量估算实验的数值模拟,并提出了改进的铀样品质量计算公式。该算法可以显著降低本实验中源-样品耦合与源中子反照等作用对铀样品质量估算精度的影响。建立了主动中子多重性计数测量探测系统模型和32个铀样品半球壳模型,模拟得到了与铀样品距离不同的DT源和AmLi源主动中子多重性计数,利用数值模拟手段检验了质量估算算法的有效性。数值模拟结果表明,改进的铀质量估算算法可以使质量估算的平均偏差率降低到10%以下。