储存环聚焦结构设计中的比例定律

阐述并证明了储存环聚焦结构设计中的比例定律.即储存环的尺寸按一定比例放大或缩小时,可以保持工作点和束流发射度不变; 介诸存环的能量改变时,其束流发射度将会随能量的平方变化.     

第三代同步辐射光源储存环支撑组件振动控制研究

第三代同步辐射光源对束流轨道稳定性要求很高,上海光源是一台在建的第三代光源,束流位置稳定度要求达到微米乃至亚微米级.地基振动会使储存环磁聚焦结构中的各种元件发生机械振动引起随时间变化的束流闭合轨道畸变,影响束流轨道稳定性.上海光源场地振动幅值大,需要研究措施控制机械组件的振动.阻尼减振是一种有效的振动控制方法,针对上海光源储存环机械组件,作者设计了一种阻尼减振方案.试验结果表明,该方案能有效地控制机械组件的振动.这对于保证上海光源的束流稳定性要求有积极意义.     

衍射极限环光源纵向束流注入非线性优化

下一代同步辐射光源储存环动力学孔径较小,因而束流注入困难,可以通过纵向束流注入解决这一问题。为了使用更长的kicker脉冲,有必要降低高频频率以增加注入束流到储存束流的时移。因为同步辐射运动,时移更长的束流有更高的动量偏差,所以通过该方法进行注入需要储存环提供足够大的能量接受度和动力学孔径。用SSRF-U的候选磁聚焦结构来展示纵向束流注入非线性优化的可行方法。由一系列高频频率的最佳结果可知,低于界限频率时kicker脉冲不会继续增长。在束流模拟中,采用界限频率与合适六级铁强度,可使SSRF-U储存环束流注入达到最高效率。     

第三代同步辐射光源储存环支撑组件振动控制研究

第三代同步辐射光源对束流轨道稳定性要求很高, 上海光源是一台在建的第三代光源, 束流位置稳定度要求达到微米乃至亚微米级. 地基振动会使储存环磁聚焦结构中的各种元件发生机械振动引起随时间变化的束流闭合轨道畸变, 影响束流轨道稳定性. 上海光源场地振动幅值大, 需要研究措施控制机械组件的振动. 阻尼减振是一种有效的振动控制方法, 针对上海光源储存环机械组件, 作者设计了一种阻尼减振方案. 试验结果表明, 该方案能有效地控制机械组件的振动. 这对于保证上海光源的束流稳定性要求有积极意义.     

BEPC储存环束流振荡频率测量

在加速器的运行和机器研究过程中,需要经常对束流振荡频率进行测量.BEPC储存环束流振荡频率测量系统包括一台频谱仪,两个条形电极装置,两个电压放大器和一个束流振荡检测器.本文介绍了经过改进的BEPC储存环束流振荡频率测量系统.     

KB镜束流截面测量系统研制

为了对衍射极限储存环的束流横向截面尺寸及发射度进行测量,设计了一套Kirkpatrick-Baez(KB)反射镜聚焦成像系统,并在上海光源(SSRF)储存环进行预制研究。该系统主体由两面垂直放置的KB反射镜组成,分别在水平及垂直方向对弯转磁铁光源点进行成像,系统工作在硬X射线波段,聚焦光斑被闪烁体X射线相机采集。对影响系统成像质量的像差和点扩散函数进行了计算。目前,实现了对束流的实时成像,可精确测量束流横向截面尺寸为75.9 μm(水平方向)和20.2 μm(垂直方向),系统稳定性(RMS)小于0.1 μm。     

第四代同步辐射光源物理设计与优化

近十年来,世界上开始大力发展第四代同步辐射光源——衍射极限储存环光源。目前我国正在建设或立项建设两台第四代同步辐射光源:高能同步辐射光源和合肥先进光源。从储存环磁聚焦结构设计与优化、束流注入与集体效应等方面,对第四代同步辐射光源的物理设计与优化进行了介绍;对国际范围内第四代储存环光源装置的研制情况进行了介绍。     

合肥先进光源储存环初步物理设计

我国最近立项建设的合肥先进光源将是一台软X射线与真空紫外衍射极限储存环光源,其电子束能量为2.2 GeV,周长为480 m,束流自然发射度为86 pm·rad,共有20个长直线节和20个短直线节。介绍了目前合肥先进光源储存环物理设计的进展情况,包括磁聚焦结构设计与优化,束流注入和集体效应的模拟与计算。     

响应矩阵分析方法在BEPC储存环上的应用

由于储存环中各种元件误差的存在, 机器的实际运行模式与设计模式有一定的偏差. 目前广泛开展的响应矩阵方法研究, 可以分析出磁铁元件以及束流位置测量元件的误差, 使束流基本参数得到校正. 介绍了用响应矩阵分析方法, 在BEPC储存环上进行的局部轨道校正的实验研究, 以及BEPC储存环束流参数校正的模拟研究.     

CSR电子冷却段磁场造成闭轨畸变及校正

电子冷却的应用提高了重离子储存环的束流品质, 也为重离子储存环的运行带来了新的课题. 电子冷却段的横向磁场在引导约束强流电子束的同时也不可避免影响了多次经过的离子轨道. 为了保证束流的安全运行, 必须将离子轨道的畸变部分限制在局部范围, 并保证轨道畸变量对储存环接收度的影响可以容忍. 讨论在建的兰州重离子储存环HIRFL-CSR电子冷却段磁场及其造成闭轨畸变和校正方案.     

Research on Changes of Focusing Structure Parameters Caused by the DC-Clearing Electric Field of Storage Ring

The changes of focusing structure parameters caused by the DC-clearing electric field of storage ring were researched. The conclusion is made that tune shift caused by the DC-clearing electric field is related to the real-time close orbit of stored beam. The clearing electric field asymmetrically distributed along the ring destroys the symmetry of the focusing structure and decreases the acceptance of storage ring. It has negative effect to the injection and accumulation process in certain condition.     

The study of the ionic wind blower with multi-needles/ring type electrodes disposed on inner wall of the cylindrical blower

Corona discharge is one of many methods that convert electrical power into mechanical force. It has been studied for various industrial fields because of its many advantages over conventional motor, such as its no moving parts, simpler structure, minimizing size and so on. In this paper, a discharge system with multiple corona electrodes disposed in a ring format, is studied by focusing on the electrical and mechanical characteristics. Effective ionic wind generation is due to the corona discharge which depends on electric field. Therefore, the electric field is affected by the voltage, discharge spacing, and distance between each corona electrodes.     

Preliminary study of EEHG-based superradiant undulator radiation at the HLS-Ⅱ storage ring

We investigate storage ring-based Echo-Enabled Harmonic Generation(EEHG) superradiant undulator radiation as a possible scheme to obtain shorter wavelengths at the HLS-Ⅱ(Hefei Light Source-Ⅱ) storage ring. In this paper we give the designation of the storage ring based EEHG up to the 26 th harmonic, where 31 nm vacuum ultraviolet light is radiated from an 800 nm seeded laser. The novelty of our design is that both the two dispersion sections of EEHG are realized by the storage ring's own magnet structure. In particular, the whole ring is used as the first dispersion section, and two modulators of the traditional EEHG can be done with the same undulator. These two dispersion sections are realized by changing the superperiod of the present lattice structure, and more precisely by changing the focusing strengths of the present structure. Since no additional magnets and chicanes are used,the beam circulates around the storage ring repeatedly, and thus this storage ring-based EEHG can have a higher repetition rate than a linac-based EEHG.     

Feasibility of a storage ring for polar molecules in strong-field-seeking states

We show, through modeling and simulation, that it is feasible to construct a storage ring that will store dense bunches of strong-field-seeking polar molecules at 30 m/s (kinetic energy of 2 K) and hold them, for several minutes, against losses due to defocusing, oscillations, and diffusion. The ring, 3 m in diameter, has straight sections that afford access to the stored molecules and a lattice structure that may be adapted for evaporative cooling. Simulation is done using a newly-developed code that tracks the particles, in time, through 400 turns; it accounts for longitudinal velocity changes as a function of external electric field, focusing and deflection nonlinearities, and the effects of gravity. An injector, decelerator, and source are included and intensities are calculated.Received: 2nd July 2004, Published online: 23 November 2004PACS: 29.20.Dh Storage rings - 41.75.Lx Other advanced accelerator concepts - 33.80.Ps Optical cooling of molecules; trapping - 39.90. + d Other instrumentation and techniques for atomic and molecular physics - 33.55.Be Zeeman and Stark effects     

Proton transport in ordered hydrogen-bonded solids

The proton transfer is considered in hydrogenbonded chains with asymmetric double-minimum potentials for proteons. The transport is described by the kinksoliton propagation in an energetically asymmetric double-well potential for a proton. The asymmetry can be caused by the spontaneous polarization in hydrogenbonded ferroelectrics, medium polarization in nonferroelectric hydrogen-bonded solids, crystallographic structure, geometry of the proton neighbourhood and internal electric field in biological macromolecules. The soliton dynamics of the system is analytically studied including the influence of a constant external electric field and damping mechanism. The velocity, energy, momentum and mobility of kinks are calculated.     

电场中(MgO)2吸附H2的理论研究

电场诱导MgO材料吸附H2是一种有效的储氢方法,而较高的场强制约其广泛应用。本文在B3LYP/CC-PVTZ水平上对电场中 (MgO)2团簇的储氢性质进行了研究,结果表明仅需外加强度为0.005 a. u. 的电场,就能使其对单个H2在Mg/O上的吸附能由无电场时的-0.143/-0.091 eV提高到-0.202/-0.134 eV. 该场强远小于其他大尺寸MgO材料达到相同吸附强度所需的电场,表明降低材料尺寸是减少储氢所需电场强度的一种可能方法。计算还表明电场中(MgO)2最多能吸附8个H2,相应的质量密度达到16.7 wt%。     

电场中(MgO)2吸附H2的理论研究

电场诱导MgO材料吸附H2是一种有效的储氢方法,而较高的场强制约其广泛应用。本文在B3LYP/CC-PVTZ水平上对电场中 (MgO)2团簇的储氢性质进行了研究,结果表明仅需外加强度为0.005 a. u. 的电场,就能使其对单个H2在Mg/O上的吸附能由无电场时的-0.143/-0.091 eV提高到-0.202/-0.134 eV. 该场强远小于其他大尺寸MgO材料达到相同吸附强度所需的电场,表明降低材料尺寸是减少储氢所需电场强度的一种可能方法。计算还表明电场中(MgO)2最多能吸附8个H2,相应的质量密度达到16.7 wt%。     

Second-Order Resonant Interaction of Ring Current Protons with Whistler-Mode Waves

We present a study on the second-order resonant interaction between the ring current protons with Whistler-mode waves propagating near the quasi electrostatic limit following the previous second-order resonant theory. The diffusion coefficients are proportional to the electric field amplitude E, much greater than those for the regular first-order resonance, which are proportional to the electric field amplitudes square E^2. Numerical calculations for the pitch angle scattering are performed for typical energies of protons Ek = 50 keV and 100 keV at locations L = 2 and L = 3.5. The timescale for the loss process of protons by the Whistler waves is found to approach one hour, comparable to that by the EMIC waves, suggesting that Whistler waves may also contribute significantly to the ring current decay under appropriate conditions.     

电场中(MgO)_2吸附H_2的理论研究

电场诱导MgO材料吸附H_2是一种有效的储氢方法,而较高的场强制约其广泛应用.本文在B3LYP/CC-PVTZ水平上对电场中(MgO)_2团簇的储氢性质进行了研究,结果表明仅需外加强度为0.005a.u.的电场,就能使其对单个H_2在Mg/O上的吸附能由无电场时的-0.143/-0.091 eV提高到-0.202/-0.134 eV.该场强远小于其他大尺寸MgO材料达到相同吸附强度所需的电场,表明降低材料尺寸是减少储氢所需电场强度的一种可能方法 .计算还表明电场中(MgO)_2最多能吸附8个H_2,相应的质量密度达到16.7 wt%.