同步辐射探测器的应用与发展

探测器是同步辐射实验的重要环节。探测器水平必须不断提高才能适应同步辐射发展的需求，最大限度地发挥先进光源为人类研究提供的强大支持作用。文章介绍了当前同步辐射实验中普遍使用的各种探测器的原理和特点，并就一些新型探测器的发展情况进行了阐述。     

Synchrotron radiation of crystallized beams

We study the modifications of synchrotron radiation of charges in a storage ring as they are cooled. The pair correlation lengths between the charges are manifest in the synchrotron radiation and coherence effects exist for wavelengths longer than the coherence lengths between the charges. Therefore, the synchrotron radiation can be used as a diagnostic tool to determine the state (gas, liquid, crystal) of the charged plasma in the storage ring. We show also that the total power of the synchrotron radiation is significantly reduced for crystallized beams, both coasting and bunched. This opens the possibility of accelerating particles to ultrarelativistic energies using small-sized cyclic accelerators.     

Yerevan synchrotron in the mode of stretcher for injected electron beam of 75 MeV energy

At the Yerevan synchrotron, an experiment is planned on the investigation of a clustered structure of nuclei, when the synchrotron is working in the mode of stretcher of the injected electron beam with energy of 75 MeV. The results of calculation of the circulating beam dynamics in the vacuum chamber of the synchrotron during 5 ms and changes of the beam parameters due to scattering of electrons by nuclei of the residual gas are presented. It is shown that the increase in the beam sizes due to scattering of electrons is permissible for available sizes of the synchrotron vacuum chamber.     

Synchrotron Radiation Facilities in China

Synchrotron radiation activities in China date back to the late 1970s. With the large increase of investment in science by the Chinese central government to promote the development of science and technology in China, quite a few large scientific projects were proposed by the scientific community, among which were Beijing Electron-Positron Collider (BEPC) and Hefei Synchrotron Radiation Light Source (HLS). The major aim of BEPC was for the studies of high energy particle physics with a parasitic synchrotron radiation facility, i.e., the so-called Beijing Synchrotron Radiation Facility (BSRF). It started operation in 1991 and became the first synchrotron radiation facility in China. As a parasitic facility, BSRF operated a few months a year and played an important role in fostering the synchrotron radiation user community in China. The HLS, a dedicated synchrotron radiation facility, came into operation almost at the same time as BSRF. As a lower energy synchrotron radiation facility, it aimed mostly at the applications of synchrotron radiation VUV wavelength range. Both BSRF and HLS were upgraded again due to strong demands from users. The rapid development of synchrotron radiation applications and facilities in the world in the 1980s and early 1990s spurred the great interest of Chinese scientists to build an advanced synchrotron radiation light source. A third generation light source was first proposed in mainland China in 1993 and was later shaped as the Shanghai Synchrotron Radiation Facility (SSRF) in 1995.     

Mössbauer optics of synchrotron radiation at an isotopic boundary

The inelastic coherent Mössbauer scattering (ICMS) of synchrotron radiation at an isotopic boundary—a flat interface between two regions of matter which have different concentrations of the Mö ssbauer isotope—is investigated theoretically. Attention is focused primarily on the ICMS component for which the absorption of a synchrotron radiation photon by a nucleus occurs with recoil, i.e., with the creation or annihilation of lattice phonons, and the subsequent process of reemission of a photon by the Mössbauer nucleus occurs without recoil, as a result of which radiation is pumped from the wide synchrotron radiation line into the narrow Mö ssbauer line. Formulas similar to the Fresnel formulas, well known in optics, for the transmission and reflection of light at a dielectric boundary are obtained for ICMS at an isotopic boundary. Specifically, it is shown that the angle of reflection for ICMS at an isotopic boundary is different from the angle of mirror reflection of a synchrotron radiation beam, and the direction of the ICMS transmitted through the isotopic boundary depends on the deviation of its frequency from the exact value of the Mössbauer resonance frequency and in general is different from the direction of propagation of the synchrotron radiation beam. The suppression of ICMS at grazing angles of incidence of the synchrotron radiation beam is analyzed. A similar problem is solved for a plate-shaped sample containing a Mössbauer isotope. It is shown that the specific nature of the ICMS at an isotopic boundary could be helpful in the problem of Mö ssbauer filtering of synchrotron radiation.     

同步辐射在古陶瓷研究中应用的现状和展望

概述了同步辐射光源的历史和优点,对同步辐射X射线荧光、X射线吸收精细结构、同步辐射X射线衍射等方法在古陶瓷工艺、产地等方面的应用现状进行了总结,并展望了同步辐射在古陶瓷研究中的应用前景.     

IKNO,a user facility for coherent terahertz and UV synchrotron radiation

IKNO (Innovation and KNOwledge) is a proposal for a multi‐user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra‐stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing third‐generation light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy.     

Injection system design for a hadron therapy synchrotron

A synchrotron is designed for tumour therapy with C⁶⁺ ions or proton. Its injector is a cyclotron, which delivers C⁵⁺ or H₂⁺ ions to the synchrotron. After comparing the methods of the single-turn injection, the multi-turn injection and the stripping injection, this paper chooses the stripping injection method. In addition, the concept design of the injection system is presented, in which the     

Injection System design for a hadron therapy Synchrotron

A synchrotron is designed for tumour therapy with C6+ ions or proton.Its injector is a cyclotron, which delivers C5+or H+2 ions to the synchrotron.After comparing the methods of the single-turn injection, the multi-turn injection and the stripping injection,this paper chooses the stripping injection method.In addition,the concept design of the injection system is presented,in which the synchrotron lattice is optimized.     

同步辐射计算机断层技术光源误差机理分析

基于同步辐射X射线的优越特性及计算机断层重建技术对材料无损检测等优点,同步辐射计算机断层重建技术被广泛应用于很多领域.本文对光源非均匀、过饱和以及过穿透的三种情形所引起同步辐射计算机断层技术重建误差的形成机理进行了分析研究,给出了三种情形所引起误差的基本形式.在此基础上,对这三种误差进行了数值模拟,模拟结果证实了分析的正确性. 关键词： 同步辐射 计算机断层 光源 误差     

Superconducting synchrotron project for hadron therapy

The project of a superconducting medical synchrotron for carbon therapy in the ion energy range from 140 to 400 MeV/n is discussed in this paper. This project is aimed at developing and building a medical synchrotron on the basis of superconducting technologies at JINR under the construction of the Nuclotron accelerator complex. A linear accelerator with alternating phase focusing is proposed for injecting carbon ion into the synchrotron, while it is planned to use a superconducting gantry weighing about 150 t for delivering radiation treatment to patients from all directions.     

Polycapillary X-ray lens for the secondary focusing Beijing synchrotron radiation source

According to intensity distribution of the synchrotron radiation source focused by a toroidal mirror at the Beijing synchrotron radiation biological macromolecule station, theoretical modeling of the Beijing synchrotron radiation source is developed for capillary optics. Using this theoretical modeling, the influences of the configuration curve of the polycapillary X-ray lens on transmission efficiency and working distance are analyzed. The experimental results of the transmission efficiency and working distance at the biological macromolecule station are in good agreement with the theoretical results.     

VUV synchrotron radiation: a new activation technique for tandem mass spectrometry

A novel experimental technique for tandem mass spectrometry and ion spectroscopy of electrosprayed ions using vacuum‐ultraviolet (VUV) synchrotron radiation is presented. Photon activation of trapped precursor ions has been performed by coupling a commercial linear quadrupole ion trap (Thermo scientific LTQ XL), equipped with the electrosprayed ions source, to the DESIRS beamline at the SOLEIL synchrotron radiation facility. The obtained results include, for the first time on biopolymers, photodetachment spectroscopy using monochromated synchrotron radiation of multi‐charged anions and the single photon ionization of large charge‐selected polycations. The high efficiency and signal‐to‐noise ratio achieved by the present set‐up open up possibilities of using synchrotron light as a new controllable activation method in tandem mass spectrometry of biopolymers and VUV‐photon spectroscopy of large biological ions.     

电子磁矩对同步辐射频谱的修正

本文从偶极子辐射场的Heaviside-Feynman表达式出发, 用经典的电动力学方法推导了考虑内禀磁矩影响后的相对论电子辐射频谱分布的表达式, 并对做匀速圆周运动的极端相对论性电子的同步辐射, 计算了两个偏振方向上的考虑磁矩修正后的辐射谱. 计算结果表明对于特征频率为ω_c的同步辐射, 如果ħω_c≥10 keV, 内禀磁矩对辐射的修正是可观的. 通过同步辐射的内禀磁矩修正, 本文讨论了电子束极化度与辐射场偏振度的依赖关系, 并基于此关系提出一种测量电子束极化度的新方法. 关键词： 同步辐射 电子内禀磁矩 同步辐射偏振度 束流极化度     

12th annual advanced photon source users meeting and workshops

The advantages of synchrotron infrared radiation for micro-spectroscopy have already been demonstrated and exploited in most of the synchrotron facilities. The development of a similar instrument at the ESRF was driven by a twofold motivation.     

Observation of trapped and passing runaway electrons by infrared camera in the EAST tokamak

In EAST, synchrotron radiation is emitted by runaway electrons in the infrared band, which can be observed by infrared cameras. This synchrotron radiation is mainly emitted by passing runaway electrons with tens of Me V energy. A common feature of radiation dominated by passing runaway electrons is that it is strongest on the high field side. However,the deeply trapped runaway electrons cannot reach the high field side in principle. Therefore, in this case, the high field side radiation is expected to be weak. This paper reports for the first time that the synchrotron radiation from trapped runaway electrons dominates that from passing runaway electrons and is identifiable in an image. Although the synchrotron radiation dominated by trapped runaway electrons can be observed in experiment, the proportion of trapped runaway electrons is very low.     

A new methodology for the near-surface strain measurement on Pd-Ag-Sn alloy

With the development of modern synchrotron sources, high-energy X-ray diffraction plays an important role in the residual stresses analysis of materials. This paper deals with the development of a new high-energy synchrotron X-ray diffraction (HESXRD) stress evaluation method for improving the near-surface strain measurement. For this purpose a new Monte Carlo simulation program has been developed to modelize any synchrotron radiation instrument. Futhermore conventional X-ray diffraction measurements have also been carried out after chemical etching, to define the surface and in-depth stresses of the sample, thus giving a reference to test the synchrotron radiation measurements. It has been shown that the reliability of this method is better than 5 μm. This method has been applied to a machined palladium alloy (Pd-Ag-Sn) plate substrate.     

Probing droplets with biological colloidal suspensions on smart surfaces by synchrotron radiation micro- and nano-beams

Droplets with colloidal biological suspensions evaporating on substrates with defined wetting properties generate confined environments for initiating aggregation and self-assembly processes. We describe smart micro- and nanostructured surfaces, optimized for probing single droplets and residues by synchrotron radiation micro- and nanobeam diffraction techniques. Applications are presented for Ac-IVD and β-amyloid (1–42) peptides capable of forming cross-β sheet structures. Complementary synchrotron radiation FTIR microspectroscopy addresses secondary structure formation. The high synchrotron radiation source brilliance enables fast raster-scan experiments.     

Morphological study of early‐stage lung cancer using synchrotron radiation

In the present study the feasibility of applying synchrotron radiation to the morphological study of early‐stage lung cancer has been investigated. Lewis lung cancer was implanted and grown in a nude mouse for different periods, and imaged using phase‐contrast synchrotron X‐rays. Morphological differences were clearly shown between the normal lung and cancerous tissues at this early stage. Irregular and tortuous angiogenesis were found in the periphery region of the developing lung cancer. Results from this study indicate that synchrotron X‐rays can be used for imaging cancer development and progression with minimal invasion.