相对论电子探测谱仪的设计及标定

考虑电子的相对论效应,根据电磁学理论和相对论公式建立了电子磁谱仪的原理;按照该原理设计了电子的磁谱仪,用补偿磁路改善了磁场的均匀性;按照磁谱仪的结构对其进行了测试和标定;以LiF热释光探测器作为记录元件,可获得相对论电子的能量分布.实验上典型的测量结果与国外计算机模拟的结果较好地一致,从而证明电子磁谱仪的可靠性.     

单能电子和γ射线与物质的相互作用

本项工作充分利用 RES— 99型相对论效应实验谱仪所能开展的系列教学实验研究单能电子和 γ射线与物质的相互作用并比较两者之间的差异 ,从而使实验者得以形象直观地认识这一近代物理教学实验中的重要内容 ;其中利用 β磁谱仪在普通实验室进行单能电子与物质相互作用的研究工作具有一定特色     

超热电子在非均匀磁场中的运动轨迹

在电子磁谱仪中实际的磁场强度分布是不均匀的,这就造成电子束在探测器上的位置和分布与均匀磁场假设下的结果的不同.根据实验测出的磁谱仪实际的磁场分布对磁谱仪中电子束的轨迹进行了研究 关键词： 电子磁谱仪     

单能电子阻止本领的研究及其在测厚中的应用--相对论效应实验谱仪系列实验之一

研究射线与物质的相互作用，在许多领域中有着重要的意义；通过单能电子阻止本领的测定及其在测厚中的应用，有助于解带电粒子与物质相互使用的规律，探讨其作用β磁谱仪在普通实验室进行单能电子与物质相互作用的研究，是相对论效应实验谱仪上机多系列实验的一个范例。     

β粒子验证相对论动量-能量关系实验中单能电子阻止本领的研究

本文利用RES-98型相对论效应实验谱仪测定了单能电子在空气中的阻止本领,对单能电子在空气中能量损失规律进行了讨论,分析了β粒子验证相对论动量-能量关系实验中空气对实验结果的影响;实现了在普通实验室进行单能电子阻止本领的测量．     

BEPC-LINAC试验束上1GeV/c多粒子磁谱仪的设计和性能测量

试验束上2Q2D结构的磁谱仪系统由2块二极磁铁和2块四极磁铁以及位置灵敏探测器组成.该磁谱仪的接收立体角5×10^–4sr,动量范围0.2—1.3GeV/c.测量了聚焦面上的束流截面和动量谱.介绍了一种测量电子与质子飞行时间差的动量测量方法.     

电子相对论径向波函数的基本特征

利用相对论平均自洽场理论,研究了电子相对论径向波函数的基本特征.电子相对论径向波函数大小分量的数量级通常相差悬殊且不"同步",核外电子的径向分布没有严格的零概率点;束缚电子相对论径向波函数大小分量的节点个数为n-l-1、波腹个数为n-l,而自由电子的节点和波腹数则趋于无穷大.电子相对论径向波函数反映了相对论效应的基本特征:相对论效应越强,小分量振幅相对越大,自由电子径向波函数振荡越剧烈.     

探测二茂铁外价轨道(e,2e)反应中的扭曲波效应

利用第三代高效率电子动量谱仪,分别在600和1500 eV两种不同入射电子能量下获得了二茂铁(ferrocene)分子外价轨道的电离能谱和电子动量谱的相关实验结果.并利用非相对论与标量相对论密度泛函方法计算出了二茂铁的重叠型和交错型两种不同构象的理论动量谱.两种构象的外价轨道一一对应,理论电子动量谱基本一样.对二茂铁的外价轨道,在低动量区观测到了强烈的扭曲波效应,这与这些轨道主要由铁原子的3d轨道构成有关.通过相对论和非相对论计算结果的比较,表明相对论效应对于二茂铁的外轨道动量分布几乎没有影响. 关键词： 二茂铁分子 电子动量谱 相对论效应 扭曲波效应     

在非相对论框架中导出泡利方程——经典电动力学与量子力学不一致之一例

在非相对论框架内,从非相对论薛定谔方程出发,将自由电子的非相对论哈密顿算符开方,推出了自由的两分量泡利旋量满足的动力学方程;进而在经典外电磁场中,利用最小耦合原理,推出了在外电磁场中非相对论电子满足的泡利方程.在此基础上,讨论经典电动力学与量子力学不一致之处,并从群表示论和量子化对粒子的自旋进行了分析.     

类Na离子振子强度的相对论效应

 采用相对论和非相对论原子自洽场方法,计算了类Na离子（原子序数为11~92）的3s-np,3p-ns和3p-nd跃迁过程的激发能和光学振子强度;通过比较相对论与非相对论的结果,研究了M壳层电子的相对论效应随原子序数的变化规律。结果表明：对n=3的跃迁过程,相对论效应主要是影响激发能,对线强度(或跃迁矩阵元)的影响不重要;对于n>3的跃迁过程,相对论效应同时影响线强度和激发能,通常对线强度的影响更大。这些结果对惯性约束聚变和X射线激光研究中需要的不透明度参数计算有重要的参考意义。     

Additional acceleration and collimation of relativistic electron beams by magnetic field resonance at very high intensity laser interaction

For the interpretation of experiments for acceleration of electrons at interaction up to nearly GeV energy in laser produced plasmas, we present a new model using interaction magnetic fields. In addition to the ponderomotive acceleration of highly relativistic electrons at the interaction of very short and very intense laser pulses, a further acceleration is derived from the interaction of these electron beams with the spontaneous magnetic fields of about 100 MG. This additional acceleration is the result of a laser-magnetic resonance acceleration (LMRA) around the peak of the azimuthal magnetic field. This causes the electrons to gain energy within a laser period. Using a Gaussian laser pulse, the LMRA acceleration of the electrons depends on the laser polarization. Since this is in the resonance regime, the strong magnetic fields affect the electron acceleration considerably. The mechanism results in good collimated high energetic electrons propagating along the center axis of the laser beam as has been observed by experiments and is reproduced by our numerical simulations. PACS 41.75.Jv; 52.38.Kd; 52.65.Cc     

Magneto‐Modulational Instability in Relativistic Plasmas

The behavior of magnetic fields generated by high frequency transverse plasmons in relativistic plasmas can be described by a set of nonlinear coupling equations, which has considered the nonlinear wave–wave, wave– particle interactions and the relativistic effects of electrons. Modulational instability of the spontaneous magnetic fields is investigated on the basis of the nonlinear coupling equations. Analytical and numerical results indicate the self‐generated magnetic fields are modulationally unstable and will be localized in a narrow region. The characteristic scale and maximum growth rate of the magnetic fields depend on the average Lorentz factor of electrons and the energy density of transverse plasmons. The relativistic effects of electrons will enhance the self‐focusing of magnetic fields (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Magnetic and electronic properties of NiAs-type chromium chalcogenides

We have computed spin-dependent energy bands, spin moments and density of states of NiAs-type CrX (X=S, Se and Te) chalcogenides using linear combination of atomic orbitals method within density functional theory as well as full potential augmented plane wave method. In addition, magnetic properties have also been computed using spin polarized relativistic Korringa-Kohn-Rostoker method. We have also obtained the first ever theoretical electron momentum densities of CrX compounds considering linear combination of atomic orbitals and compared the results with the isotropic Compton profiles measured using 20 Ci ¹³⁷Cs Compton spectrometer. The Fermi surface topology and magnetic properties are discussed in terms of majority and minority energy bands and density of states. In addition, to highlight the role of Cr (3d) electrons in such type of chalcogenides, we have also reported the magnetic Compton profile of CrTe using the Korringa-Kohn-Rostoker method.     

Secondary electron time detector for mass measurements at CSRe

The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by an electric field and deffected 180° by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps (FWHM) was obtained in the laboratory. A mass resolution around 8×10-6 for m/m was achieved by using this time detector in a pilot mass measurement experiment.     

Relativistic second-harmonic generation in a laser-produced plasma

Summary In this paper the relativistic second-harmonic generation of a high-power laser radiation in a laser-produced plasma has been studied theoretically in the presence of a self-generated magnetic field. The relativistic Vlasov equation has been employed for the nonlinear response of the electrons in the hot magnetized plasma. It is observed that the power conversion efficiency of the generated second harmonic wave is much higher for relativistic calculations than that for nonrelativistic calculations. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Effect of the self-field of an intense relativistic electron beam on its interaction with matter

The effect of the self-field of an intense relativistic electron beam on its interaction with a dense medium was studied by solving a system of equations consisting of the kinetic equation for the fast electrons, the hydrodynamic equations for the plasma electrons, and Maxwell's equations for the electromagnetic field. It was assumed that the macroscopic parameters of the medium (its density, conductivity, and electron collision frequency) were independent of time. The system of equations was solved using high-order perturbation theory. The results show that a magnetic field is formed by the beam of fast electrons and to an equal degree by a current of thermalized electrons, which has not been taken into account before. It is shown also that the magnetic field of the beam affects its transmission through matter. In particular, the penetration depth of the electrons in matter and the transverse dimensions of the beam are both smaller than in a weak-current beam.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 10, pp. 19–24, October, 1987.The author deeply thanks K. A. Dergobuzov for support of the work, and A. V. Arzhannikov, V. A. Klimenko, and A. V. Lapp for useful discussions.     

Synchrotron resonance maser

Attention is drawn to an obscure formula derived from relativistic quantum electrodynamics in the mid-'60s by Sokolov and Ternov for induced absorption and emission from highly relativistic electrons in a static uniform magnetic field. From their results, we develop handy formulae and graphs to help in preliminary designs for radiation sources to operate at high synchrotron harmonics. Approximate design parameters are given for 100 kW oscillators operating at wavelengths below 3mm, employing magnetic fields of less than 12 kG. It is shown that the Sokolov-Ternov formula can also be deduced from classical relativistic plasma wave theory, but for a numerical factor in one term. This term is shown to describe a gain mechanism which has apparently received scant notice in the gyrotron literature.     

Origin of the giant magnetic moments of Fe impurities on and in Cs films

We have explored the origin of the observed giant magnetic moments ( approximately 7&mgr;(B)) of Fe impurities on the surface and in the bulk of Cs films, using the relativistic local-spin-density-approximation method. We have found that Fe impurities in Cs behave differently from those in noble metals or in Pd. Whereas the induced spin polarization of Cs atoms is negligible, the Fe ion itself is a source of the giant magnetic moment. The 3d electrons of Fe in Cs are localized as the 4f electrons in rare-earth ions so that the orbital magnetic moment becomes as large as the spin magnetic moment. The calculated total magnetic moment M = 6.43&mgr;(B) is close to the experimentally observed value.     

SPECTRAL VARIABILITY AND TRANSIENT INJECTION OF RELATIVISTIC ELECTRONS FOR BL LAC OBJECTS

The spectral hardening with increasing intensity in optical range for four BL Lac objects have been found by analyzing our observed data. Making use of the synchrotron loss of transient injection of relativistic electrons, we succeeded in explaining the phenomenon of the spectral hardening in the outburst phase. The value of magnetic intensity and the limit condition of the transient injection of relativistic electrons seem to be reasonable.