A Potential Method for Diagnostics of Subfemtosecond Electron Beams Using Coherent Optical Transition Radiation

Russian Physics Journal - Coherent transition radiation (CTR) is widely used in determining the longitudinal e-beam dimensions in the accelerator technology applications. In this study, the CTR...     

小型化自屏蔽电子束辐照装置研制

介绍了一种小型化自屏蔽电子束辐照装置的结构方案设计和工作原理.该辐照装置已经完成了研制工作,以加速器技术为核心,突出了小型化和自屏蔽的设计理念,实现了电子束能量2.5MeV,束流功率1.2kW,扫描宽度300mm,环境剂量2uSv/h的技术指标,可用于普通工厂的产品在线辐照或者车载式安装应用.实际运行表明该辐照装置工作稳定、安全可靠、小型方便.     

小型化自屏蔽电子束辐照装置研制

介绍了一种小型化自屏蔽电子束辐照装置的结构方案设计和工作原理. 该辐照装置已经完成了研制工作, 以加速器技术为核心, 突出了小型化和自屏蔽的设计理念, 实现了电子束能量2.5MeV, 束流功率1.2kW, 扫描宽度300mm, 环境剂量2uSv/h的技术指标, 可用于普通工厂的产品在线辐照或者车载式安装应用. 实际运行表明该辐照装置工作稳定、安全可靠、小型方便.     

Higher Harmonic Generation of Coherent Sub-THz Radiation at Lifshitz Transition in Gapped Bilayer Graphene

Journal of Experimental and Theoretical Physics - The microscopic quantum theory of nonlinear interaction of strong coherent electromagnetic radiation with gapped bilayer graphene is used for...     

Partial Focusing of Coherent Optical Transition Radiation and Measurement of Transverse Size of Femtosecond Electron Bunches

Russian Physics Journal - Coherent optical transition radiation (COTR) from femtosecond electron bunches is simulated using an earlier proposed model. It is shown that partial screening of the COTR...     

Diffracted X Rays and Resonance (Coherent) Transition Radiation Generated by High-Energy Charged Particles

The present review is devoted to the current status of research in electromagnetic radiation generated by relativistic charged particles that pass with constant velocities through periodic media. Two particular examples are considered: the first conserves Bragg's scattering of the pseudo-photon field of the charged particle in crystals, and the second concerns the Fresnel scattering of pseudo-photons in a periodic medium. Both effects are very promising for the development of new compact adjustable x-ray sources.     

Molecular Spectroscopy with Coherent Radiation Sources

Various characteristics of molecules have been clarified by spectroscopic methods in which the interactions of molecules with the radiation field were investigated. A stationary response of a molecule excited by a radiation field appears as a spectral line. Information on molecules may be obtained from position (resonance frequency), intensity, and shape and width of the spectral line. So far the interaction of molecules with the radiation field has been studied primarily in a “frequency domain.” Although molecular spectroscopy is one of the research fields in modern science which has the longest history, a variety of important aspects have been demonstrated very recently in this field as radiation sources have been improved. When the radiation field is “weak,” the photon nature of the radiation field is dominant in the interaction with a molecule, such as in the cases of emission, absorption, and scattering of photons. When the radiation field is “strong,” in the sense that many photons exist in a proper mode of the radiation field, the wave nature of the field plays an important role in the interaction. In this case the radiation may be described in the form of the classical field, say, a sinusoidal function of the time and spatial coordinates, coherently interacting with the molecule, which is described quantum mechanically. Here nonlinear properties would appear in the interactions: saturation in absorption, induced scattering, multiphoton processes, coherent transients, etc.     

Topics in Coherent Synchrotron Radiation: Experimental Consequences of Radiation Impedance

Coherent synchrotron radiation (CSR) is now an established source of radiation in the terahertz region, with flux capabilities many orders of magnitude higher than conventional SR sources. Accordingly, CSR is playing an ever-increasing role in the field of Far-IR spectroscopy at synchrotron facilities around the world. However, with the improvement in spectroscopic resolution, the incident CSR spectra from several facilities are displaying intensity profiles that appear to be modulated by periodic peaks or deep indentations, while theory predicts a featureless distribution. After eliminating the usual suspects, like multiple reflections from windows, etc., one looks for a deeper explanation, such as the role played by the radiation impedance. This impedance is largely defined by the vacuum chamber in the region of the bend magnets, but probably with some effects from the straight sections as well.     

Formation of Gradient Metalloceramic Materials Using Electron-Beam Irradiation in the Forevacuum

Russian Physics Journal - Results of using an electron beam formed by a forevacuum plasma electron source to sinter metalloceramic materials in powder form are reported. As the materials to be...     

Far Infrared Coherent Synchrotron Edge Radiation at ANKA

The Fifth SOLEIL Users' Meeting, attended by no less than 344 participants from 11 countries, took place on January 20–21, 2010, at the Ecole Polytechnique (Palaiseau) for the six plenary lectures (Photo 1) and parallel sessions, and at SOLEIL for the poster session and the commercial exhibition. Prior to the main meeting, a satellite workshop was organized on January 18–19 in the field of high-energy photoemission spectroscopy (HAXPES) in relation to the new future GALAXIES beamline.     

First Observation of the Forbidden k-X Transition of (13)C(16)O

A weak rotationally resolved absorption band of (13)C(16)O has been identified from photographic spectra at 1078 ? and assigned to the forbidden transition from the X(1)Sigma(+) (v = 0) ground state to the k(3)Pi (v = 3) valence state. It is similar in structure to the corresponding band of (12)C(16)O but due to the fact it was photographed at a relatively low pressure only the two strongest rotational branches could be positively identified. It is the first time that the forbidden k-X transition has been observed for (13)C(16)O. The measured isotopic shift in the band origin provides independent confirmation of the new vibrational assignment of the k state by G. Berden, R. T. Jongma, D. Van der Zande, and G. Meijer (J. Chem. Phys. 107, 8303-8310 (1997)). Copyright 2000 Academic Press.     

Transition Radiation,Bremsstrahlung und Plasmastrahlung

The visible and ultraviolet radiation emitted from electron bombarded metal targets was investigated for normal and oblique electron incidence in the range of primary energiesE=6?40 keV. For normal incidence the observed spectra could be separated in transition radiation and bremsstrahlung because of their different energy dependences. When silver targets were bombarded at oblique incidence a third radiation was observed which is peaking nearλ=3500 Å (half widthΔ λ=200?300 Å). For grazing indicence (α=0,5° against the target surface) under UHV conditions the peak intensity is 100 times greater than transition radiation at normal incidence. Due to the wavelenght, the dependence on the angle of incidence, and the strong dependence on surface contaminations this radiation is assumed to be caused by surface plasmon excitation in the silver target.     

Controlled Quantum Teleportation of Superposed Coherent State Using GHZ Entangled Coherent State

Controlled quantum teleportation of superposed coherent states using GHZ entangled 3-mode coherent states is studied. Proposed scheme can be implemented experimentally using linear optical components such as a symmetric lossless beam splitter, two phase-shifters and two photon counters. Fidelity is found close to unity for appreciable mean number of photons in coherent states and is 0.99 for mean photon number equal to two.

     

THz Coherent Vavilov-Cherenkov Radiation in a Special Three-Mirror Cavity

In the modern science and technology a compact and having enough output power terahertz radiation source working in room temperature have earned great attention. This paper is devoted to utilize electron bunches stimulate Vavilov-Cherenkov Radiation (VCR) in a special three-mirror quasi-optical cavity to generate coherent THz waves. This novel three-mirror quasi-optical resonant cavity has the coaxial field pattern which enables field establish in this cavity effectively. The analytical theory of the radiation exited by a train of electron bunches in the special kind of three-mirror cavity has been carried out and the coherent VCR has been achieved by the computer simulation. All those shows that this method can be used to establish useful THz radiation source by the normal electron gun and the commonly used microwave devices.     

X射线激光器——新兴的短波长相干光源

Ｘ射线激光器是运行在电磁辐射波谱中Ｘ射线波段的短波长相干光源，通常，Ｘ射线激光器都采用高功率激光器作为泵浦源，强激光与靶相互使用形成的高温等离子体作为工作介质，并采用单程（或双程）行波放大的运行方式，近１０年来，Ｘ射线激光器的研制工作取得了重大进展，并开始了Ｘ射线激光应用的初步研究，现在正朝着提供高亮度，有较好相干性并且价格便宜的小型短波长Ｘ光光源的目标努力。     

Entanglement Properties of Two-Mode Squeezed Coherent States in Radiation Field

Entanglement properties of two-mode squeezed coherent states in the radiation field are investigated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.     

具有时间分辨能力的高能强流电子束光学渡越辐射测量系统

光学渡越辐射作为高能强流电子束束流参数测量的一种方式, 具有时间响应快、分辨率高等特点, 可以测量电子束的束剖面、发散角、能量等多个参数；通过电子束束参数的时间分辨测量则能够了解电子束产生、运输中的问题, 非常有利于加速器的研究与调试. 一种具有时间分辨能力的、利用光学渡越辐射进行高能强流电子束参数测量的系统被建立起来, 并应用到了18.5MeV, 2.5kA, 90ns的实际的电子束束参数的在线测量中, 具有以10ns的时间间隔和3ns的曝光时间来获得90ns内相应的时间分辨的束发射度的变化值的能力, 为加速器的研究提供了又一个强有力的测试手段. 该系统具有的时间分辨能力最高到达10ns, 一次可以拍摄到8幅图像, 最小的曝光时间为3ns, 图像分辨率为1376×1035, 幅面可以达到φ80mm以上.