Analysis of undulator radiation with an electromagnet undulator

In this paper we discuss the theory of undulator radiation in an electromagnet undulator. We discuss the spectral properties of undulator radiation when electrons are injected off the undulator axis. This paper highlights the distinctive features of the radiation spectrum from electromagnet undulators, as compared to PPM undulators.     

Electron radiation on an undulator

The emission is considered for an electron moving in an undulator of finite length; the polarization and the emission spectrum are examined.     

Hard undulator radiation in an inverse medium

X-ray radiation from fast electrons in undulators filled with an inverse medium is studied. A formula for the spectral density of the number of photons is derived. The intensity zeroth harmonics, as well as the intensity of radiation in zero undulator field, are described by the Tamm-Frank formula for Cherenkov radiation. It is shown that the spectral density of emitted photons in a wavelength range of λ ? 0.4–2.0 Å in such a medium can be increased by four orders of magnitude as compared to the radiation intensity in a vacuum undulator. The energy of emitted electrons in the former case must be in an interval of 5-2 GeV, while electrons with an energy of 14-6 GeV are required in vacuum undulators.

     

Neutrino analog of undulator radiation

The neutrino analog of the undulator radiation of ultrarelativistic electrons is studied theoretically. A new source of electron neutrino pairs based on electronic accelerators and single crystals as the undulator is proposed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 69–74, April, 1985.     

Incoherent radiation of fast electrons in a crystalline undulator

Incoherent radiation of high-energy particles in a crystal is caused by the thermal scattering of atoms relative to their equilibrium lattice positions. An earlier developed procedure for incoherent radiation simulation is applied to the case of electron motion in a sinusoidally curved crystal. The simulation results agree with the data of recent experiments at the Mainz Microtron (MAMI).     

Femtosecond undulator radiation from sliced electron bunches

At the 1.7-GeV electron storage ring BESSY II, a first source of synchrotron radiation with 100 fs pulse duration, variable (linear and circular) polarization, tunable photon energy (300 to 1400 eV), and excellent signal-to-background ratio was constructed and is now in routine operation.     

Change in the kind of polarization of undulator radiation

The radiation properties of relativistic electrons in an undulator comprised of two parts are investigated. The dependence of the polarization properties of the radiation on the mutual location and orientation of both parts of the undulator is shown.Translated from Izvestiya Vysshikh uchebnykh Zavedenii, Fizika, No. 3, pp. 76–80, March, 1978.     

Emission by electrons in an undulator

Classical-theory methods are applied to the emission from an electron moving in an ideal undulator of infinite length with piecewise-homogeneous magnetic field. The spectral and angular distributions of the radiation are deduced together with the polarization and total power.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 50–54, October, 1973.     

Photoionization of highly charged ions using an ECR ion source and undulator radiation

Photoionization of Xe4+ to Xe7+ ions was studied by combining an electron cyclotron resonance ion source with synchrotron radiation. Multiconfiguration Dirac-Fock calculations were performed to interpret the data. Many autoionization lines were measured and identified, resulting from excitation of a 4d electron into nf and np orbitals followed by Auger decay of the excited states. Continuum photoionization is negligible for the higher members of the isonuclear series.     

参数激励与晶体摆动场辐射的稳定性

寻找新光源, 特别是短波长相干光源备受关注. 本文讨论了晶体摆动场辐射作为短波长激光的可能性和必须满足的基本条件; 指出了至今尚未获得可利用的短波长激光可能不只是技术原因, 而且还有物理原因. 利用参数激励方法对这个问题进行了分析. 在经典力学框架内和偶极近似下, 引入正弦平方势, 把粒子运动方程化为具有阻尼项和参数激励项的摆方程. 利用Melnikov方法讨论了系统的稳定性, 并对系统的临界条件进行了分析. 结果表明: 系统的稳定性与其参数有关, 只需适当调节这些参数, 系统的稳定性就可以原则上得到保证. 关键词： 晶体摆动场辐射 沟道辐射 参数激励 稳定性     

Crystalline undulator radiation and sub-harmonic bifurcation of system

Looking for new light sources, especially short wavelength laser light sources has attracted widespread attention. This paper analytically describes the radiation of a crystalline undulator field by the sine-squared potential. In the classical mechanics and the dipole approximation, the motion equation of a particle is reduced to a generalized pendulum equation with a damping term and a forcing term. The bifurcation behavior of periodic orbits is analyzed by using the Melnikov method and the numerical method, and the stability of the system is discussed. The results show that, in principle, the stability of the system relates to its parameters, and only by adjusting these parameters appropriately can the occurrence of bifurcation be avoided or suppressed.     

Hard undulator radiation in a dispersive medium in the dipole approximation

Hard undulator radiation of relativistic particles in a dispersive medium is investigated. Under certain conditions the undulator radiation spectrum is narrowed. It is shown that the narrowing effect makes it possible to obtain an intense, quasi-monochromatic, sharply directed flux of ultraviolet and harder quanta in contemporary accelerators.     

First results of investigation of radiation from positrons in a crystalline undulator

Radiation emitted by positrons moving in a periodically deformed crystal has been experimentally observed for the first time. Radiation spectra have been measured in a wide energy range. Experimental evidence has been obtained for an undulator peak in a radiation spectrum, which is qualitatively consistent with calculations. Crystalline undulators ensure an equivalent magnetic field of 1000 T and a period in the submillimeter range and can therefore be used to generate x-ray and gamma radiation that is a hundred times harder than radiation in usual undulators.     

Effect of the correction of the motion of relativistic electrons in a magnetic undulator on the properties of undulator radiation

The properties of undulator radiation of electrons in a planar undulator with an arbitrary number of periods of the magnetic field and with correcting sections along the ends of the undulator are investigated. It is shown that in setups with relatively large number of periods of the field, the emission of particles in the correcting sections has a large effect on the general characteristics of undulator radiation of electrons in the setup. The experiment confirmed the basic assumptions of the theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 52–58 November, 1981.