次谐波聚束器相位控制的算法改进

 为实现次谐波聚束器的数字化相位控制,利用下变频、IQ调制解调技术及商业化的PXI系统,开发了以LabVIEW为平台的低电平控制器。控制器采用了具有自学习和自适应能力的单神经元自适应PID的控制算法,满足了相位稳定度的要求,通过现场测试与传统PID算法进行比较,验证了该算法稳定性好、响应快、抗干扰能力强。     

Study of multipacting effect in superconducting cavity

A number of superconducting cavities of axis-symmetric geometry have been considered to study the effect in order to achieve the desired performance. It is shown that the multipacting effect is strongly dependent on the condition of the RF surface and can be suppressed with reconsideration of the geometry. The simulation result is compared with the result of the semi-analytical model in the end.     

HM-J16双光子电子直线加速器

简要叙述了 HM-J1 6加速器的设计思想和设计特点。设计了一台采用射频功率反馈的射线能量范围为 6～ 1 6Me V的双光子电子直线加速器。其最大辐射野为 4 0 cm× 4 0 cm,双光子剂量率均大于3 60 c Gy/ (min·m)。     

上海光源150MeV电子直线加速器的设计与调试

上海光源150MeV直线加速器由热阴极电子枪,次谐波聚束器和聚束器,四根S波段等梯度行波加速管及必要的磁铁等组成.外围还有由从微波到直流的电源和功率源,性能监测和联锁控制的硬件和软件等.概述了150MeV直线加速器的设计,安装,调试和达到的结果.     

The QE numerical simulation of PEA semiconductor photocathode

Several kinds of models have already been proposed to explain the photoemission process. The exact photoemission theory of the semiconductor photocathode was not well established after decades of research. In this paper an integral equation of quantum efficiency (QE) is constructed to describe the photoemission of positive electron affinity (PEA) of the semiconductor photocathode based on the three-step photoemission model. Various factors (e.g., forbidden band gap, electron affinity, photon energy, incident angle, degree of polarization, refractive index, extinction coefficient, initial and final electron energy, relaxation time, external electric field and so on) have an impact on the QE of the PEA semiconductor photocathode, which are entirely expressed in the QE equation. In addition, a simulation code is also programmed to calculate the QE of the K₂CsSb photocathode theoretically at 532 nm wavelength. By and large, the result is in line with the expected experimental value. The reasons leading to the distinction between the experimental and theoretical QE are discussed.     

室内模型实验中低强度桩侧应变片粘贴技术与应用

表面粗糙的桩与桩间土共同受力后发生相对位移,在低强度桩侧面有效粘贴应变片以测试轴力传递规律是一个难点.在组合群桩复合地基室内模型试验中,本文结合传统内贴法和外贴法两种贴片方式的优点,提出并采用凹槽法在低强度实心模型桩外侧面贴片,即在桩侧预留凹槽、用环氧树脂对贴片部位进行表层处理,在贴片后密封凹槽,并给出了典型测试结果.分析认为:凹槽法贴片技术有效可行,可供室内含桩地基基础模型试验借鉴.     

上海光源次谐波聚束器的优化设计及测试

 介绍了上海光源直线加速器499.654MHz次谐波聚束器的物理设计、结构、加工、微波测量和试验、运行等的情况。通过2维、3维电磁软件的数值模拟方法对腔型、结构尺寸、电磁参数、调谐范围进行了优化设计,现该腔已经加工完成,并对其进行了电参数测试,结果与物理设计指标吻合很好。在上海光源的束流指标调试过程中,该腔能长期稳定运行。     

上海光源150MeV电子直线加速器的设计与调试

上海光源150MeV直线加速器由热阴极电子枪, 次谐波聚束器和聚束器, 四根S波段等梯度行波加速管及必要的磁铁等组成. 外围还有由从微波到直流的电源和功率源, 性能监测和联锁控制的硬件和软件等. 概述了150MeV直线加速器的设计, 安装, 调试和达到的结果.     

Study of multipacting effect in sub-harmonic buncher of SSRF linac

During the design process, multipacting effect has been taken into consideration using a 2D simulation code MultiPac and all of the corners are rounded to suppress the multipacting effect in the pill-box cavity. However, unexpected multipacting effect prevents the increase of the input power when the magnetic field of focusing coils is added after adequate conditioning and a novel method is adopted to suppress it by introducing extra coils to counteract the field. This paper focuses on the simulation of multipacting effect in different magnetic field configurations. The experimental observations and simulation results of multipacting effect are presented and details of the multipacting process are also analyzed.     

束流诊断虚拟加速器环境开发

为了更好的测试控制方法和开发上层控制软件,本文提出了一种基于ELEGANT和SDDS Toolkit的虚拟加速器环境。在这个虚拟环境下,可以将底层物理模拟软件与上层控制软件通过EPICS控制通道及Matlab脚本进行数据分析及处理。本文描述了在该虚拟加速器环境中束流参数测量和轨道控制等软件的开发和测试,并探讨了该虚拟加速器的设计理念和未来可能的应用。