SECRAL在18GHz频率下产生强流高电荷态离子束的初步结果

A Superconducting ECR ion source with Advanced design in Lanzhou (SECRAL) was successfully built to produce intense beams of highly charged ions for Heavy Ion Research Facility in Lanzhou (HIRFL).The ion source has been optimized to be operated at 28GHz for its maximum performance.The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping.For 28GHz operation,the magnet assembly can produce peak mirror fields on axis 3.6T at injection,2.2T at extraction and a radial sextupole field of 2.0T at plasma chamber wall.A unique feature of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. During the ongoing commissioning phase at 18GHz with a stainless steel chamber,tests with various gases and some metals have been conducted with microwave power less than 3.2kW and it turned out the performance is very promising.Some record ion beam intensities have been produced,for instance,810eμA of O~(7 ),505eμA of Xe~(20 ),306eμA of Xe~(27 ),21eμA of Xe~(34 ),2.4eμA of Xe~(38 ) and so on.To reach better results for highly charged ion beams,further modifications such as an aluminium chamber with better cooling,higher microwave power and a movable extraction system will be done,and also emittance measurements are being prepared.     

Mechanical Analysis and Measurements of a Multicomponent NbTi/Cu Superconducting Magnets Structure for the Fully Superconducting Electron Cyclotron Resonance Ion Source

A fully superconducting electron cyclotron resonance(ECR) ion source(SECRAL Ⅱ) is currently being built in the Institute of Modern Physics,Chinese Academy of Sciences.Its key components are three superconducting solenoids(Nb-Ti/Cu) and six superconducting sextupoles(Nb-Ti/Cu).Different from the conventional superconducting ECR magnetic structure,the SECRAL Ⅱ includes three superconducting solenoid coils that are located inside the superconducting sextupoles.The SECRAL Ⅱ can significantly reduce the interaction forces between the sextupole and the solenoids,and the magnets can also be more compact in size.For this multi-component SECRAL Ⅱ generating its self Held of ~8T and being often exposed to the high self Geld,the mechanical analysis has become the main issue to keep their stress at 200 MPa on coils.The analytical and experimental results in mechanics are presented in the SECRAL Ⅱ structure.To improve the accuracy and efficiency of analysis,according to the composite rule of micromechanics,the equivalent uniform windings are used to simuiate the epoxy-impregnated Nb-Ti/Cu coils.In addition,using low temperature strain gauges and a wireless fast strain acquisition system,a fundamentai experiment on the strains developments of a sextupole is reported.Finally,based on our analysis,the stresses and deformations for its assembly of each SECRAL Ⅱ coil will be further optimized.     

The magnet design for the HLS storage ring upgrade project

In order to improve the performance of the Hefei Light Source (HLS), in particular to get higher brilliance synchrotron radiation and increase the number of straight section insertion devices, an upgrade project called HLSII will be launched soon. The storage ring lattice, which has a double bend achromatic structure with four periods, comprises eight dipoles, 32 quadrupoles and 32 combined function sextupoles. The design and analysis of the magnets are shown in this paper, along with the optimization of the multipurpose combined function magnet, which consists of three magnets: skew quadrupole, horizontal dipole and vertical dipole, with the main sextupole magnet. This type of magnet is the first one that has been designed and used in China. The mechanical design and fabrication procedures for the magnets are also presented.     

Study and design of RF coupler for Chinese ADS HWR superconducting cavity

An RF power coupler is a key component of the superconducting accelerating system in Chinese ADS proton linac injector I, which is used to transmit 15 kW RF power from the power source to the superconducting HWR cavity. According to the requirement of working frequency, power level, transmission capability and cooling condition, the physics design of coupler has been finished, which includes RF structure optimization, thermal simulation, thermal stress analysis and so on. Based on this design, the prototype of HWR coupler has been fabricated, and it has successfully passed the high power test.     

Study and design of RF coupler for Chinese ADS HWR superconducting cavity

An RF power coupler is a key component of the superconducting accelerating system in Chinese ADS proton linac injector I, which is used to transmit 15 kW RF power from the power source to the superconducting HWR cavity. According to the requirement of working frequency, power level, transmission capability and cooling condition, the physics design of coupler has been finished, which includes RF structure optimization, thermal simulation, thermal stress analysis and so on. Based on this design, the prototype of HWR coupler has been fabricated, and it has successfully passed the high power test.     

Optimal design of a 7 T highly homogeneous superconducting magnet for a Penning trap

A Penning trap system called Lanzhou Penning Trap（LPT） is now being developed for precise mass measurements at the Institute of Modern Physics（IMP）.One of the key components is a 7 T actively shielded superconducting magnet with a clear warm bore of 156 mm.The required field homogeneity is 3 × 10-7 over two 1 cubic centimeter volumes lying 220 mm apart along the magnet axis.We introduce a two-step method which combines linear programming and a nonlinear optimization algorithm for designing the multi-section superconducting magnet.This method is fast and flexible for handling arbitrary shaped homogeneous volumes and coils.With the help of this method an optimal design for the LPT superconducting magnet has been obtained.     

Physical design of superconducting magnet for ADS injection Ⅰ

A superconducting solenoid prototype magnet for Accelerator Driven Subcritical System (ADS) Injection Ⅰ has been designed and fabricated, which has also been tested in a liquid Helium state inside a vertical Dewar in the Haerbin institute of Technology in November 2012. The design current was 210 A, when the test current reached 400 A no quench occurred so the solenoid magnet was forced to quench by the embedded heaters. The integral field strength, leakage field at the nearby upstream and downstream superconducting spoke cavities all meet the design requirements. At the same time, it also checked the reliability of the vertical test Dewar and the quenched detection system. The superconducting prototype magnet has accumulated valuable experiences for the coming batch magnets production and cryogenic test.     

RIKEN超导ECR离子源磁体系统的设计

Superconducting magnet system for a 28GHz ECR ion source has been designed.The maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,respectively.The hexapole magnetic field is about 2T on the inner surface of the plasma chamber.The superconducting coils consist of six solenoids and six racetrack windings for a hexapole field.Two kinds of coil arrangements were investigated:one is an arrangement in which the hexpole coil is located in the bore of the solenoids,and another is the reverse of it.The coils use NbTi-Copper conductor and are bath-cooled in liquid helium.The six solenoids are excited with individual power supplies to search for the optimal axial field distribution.The current leads use high Tc material and the cryogenic system is operated in LHe re-condensation mode using small refrigerators.The thermal insulated supports of the cold mass have also been designed based on the calculated results of the magnetic force.The heat loads to 70K and LHe stages were estimated from the design of the supports,the current leads and so on.     

Study on the frequency tuning of the half-wave resonator at IMP

The RF and mechanical coupled analyses are essential in superconducting cavity design in order to predict the deformation of the cavity walls and the frequency shift caused by the deformation. In this paper, the detuning caused by both bath helium pressure and Lorentz force is analysed and a tuning system has been investigated and designed to compensate the detuning by deforming the half-wave resonator along the beam axis. The simulations performed with ANSYS code show that the tuning system can adjust and compensate the frequency drift due to external vibrations and helium pressure fluctuation during operation.     

Progress of the 87Rb Fountain Clock

A fountain atomic clock based on cold 87Rb atoms has been in operation in our laboratory for several months. We therefore report the design of the rubidium fountain clock including its physical package, optical system and daily operation. Ramsey fringes have been attained with the signal to noise ratio of about 100.     

超导离子源铌三锡六极线圈镜像磁场约束结构的优化设计

中国科学院近代物理研究所正在进行国际首台45 GHz全铌三锡超导离子源FECR(Fourth Electron Cyclotron Resonance)磁体的研制,该离子源磁体线圈由六个铌三锡超导六极线圈和四个铌三锡超导螺线管线圈组成。由于单根超导线绕制异形六极线圈(非标准鞍型)技术难度大,且铌三锡超导性能对应力敏感,为了测试单个铌三锡六极线圈性能能否达到设计指标,基于铝合金壳层结构和Bladder-Key精确预紧技术,设计了镜像磁场约束结构。本工作主要阐述了运用ANSYS参数化设计编程对镜像磁场结构进行优化设计的过程和优化后的镜像磁场结构,确定了室温预应力大小,并给出了线圈经过室温预紧、冷却降温和加电励磁后的最大等效应力。进一步结合实际六极线圈制作公差(±0.1 mm),分析和评估了公差对镜像磁场结构中六极线圈预应力施加的影响。     

先进超导导体测试装置设计分析

针对聚变工程大型超导导体样品在高场下的性能测试需求,设计了内径0.6m、磁场13T的背景磁体系统。磁体系统由6层12个分离式超导线圈组成,线圈采用常规的螺线管结构,由外至内分别使用NbTi、Nb₃Sn和YBCO三种超导材料绕制而成;在直径500mm的测试区域范围内产生最高达13.22T的背景磁场,均匀性不低于95%。介绍了磁体线圈主要设计参数,用有限元软件完成电磁、结构分析。结果表明,设计合理可靠,能够满足导体测试装置的需求。     

Design of a conduction-cooled 4 T superconducting racetrack for a multi-field coupling measurement system

A conduction-cooled superconducting magnet producing a transverse field of 4 T has been designed for a new generation multi-field coupling measurement system,which will be used to study the mechanical behavior of superconducting samples at cryogenic temperatures and intense magnetic fields.A compact cryostat with a two-stage GM cryocooler is designed and manufactured for the superconducting magnet.The magnet is composed of a pair of flat racetrack coils wound by NbTi/Cu superconducting composite wires,a copper and stainless steel combinational former and two Bi_2Sr_2CaCu_2O_v superconducting current leads.The two coils are connected in series and can be powered with a single power supply.In order to support the high stress and attain uniform thermal distribution in the superconducting magnet,a detailed finite element(FE) analysis has been performed.The results indicate that in the operating status the designed magnet system can sufficiently bear the electromagnetic forces and has a uniform temperature distribution.     

SECRAL超导磁铁电源控制

超导离子源(SECRAL)的超导磁铁电源的控制非常重要。为防止超导磁铁的失超,需要对超导磁铁电源采用恰当的策略进行控制。在SECRAL系统中,4台电源分别为4个超导线圈独立供电,供电的电流大小不同,电流上升和下降的速率也不同。4个线圈的电流不平衡,将导致整个超导磁铁失超,所以超导线圈的电流上升和下降过程必须协同完成。为了提升磁铁电源的安全性和稳定性,设计并实现了一个远程控制系统。在硬件方面使用串口通讯服务器实现TCP/IP网络通讯与RS232串行通讯间的协议转换。软件使用VC++直接对串口编程完成。该系统能够自动完成4台电源的同步操作,简化了超导离子源SECRAL的调试过程,提高了操作过程中的安全性。     

ITER 超导馈线系统的设计

ITER( 国际热核试验堆) 采用超导馈线系统传输磁体线圈所需电流、冷却液及数据信号, 并在失超等异常情况, 通过馈线转移磁体能量, 以保护整个磁体系统。介绍了国际热核试验堆超导馈线系统的结构及设计情况, 为同类型超导磁体的馈线设计提供了有益的参考。     

冷却储存环主环注入线四极磁铁测量

 介绍了兰州重离子加速器冷却储存环工程主环注入线四极磁铁谐波测磁系统和谐波磁场测量结果。分析了磁铁误差产生的原因以及磁铁加工存在的问题和注意事项。     

欧洲FAIR中超导二极磁体样机的初步设计与分析

介绍了欧洲FAIR超导二极磁体样机设计的背景及设计要求,以及磁体样机的几个大部件及其作用。用有限元分析软件ANSYS进行了线圈电磁性能分析,得到其磁场、电感、储能随电流的变化曲线,并对其中的一个部件线圈盒进行了结构分析,为下一步的设计提供参考。     

开放式自屏蔽全身成像高场超导MRI磁体优化设计

本文发展了开放式自屏蔽全身成像高场超导磁共振成像（MRI）磁体的优化设计方法,使设计出来的磁体仅有4 对超导线圈. 这种开放结构的超导MRI磁体优化设计方法集成了线性规划算法和遗传算法. 通过迭代线性规划算法可以在考虑成像区域（DSV）磁感应强度约束、磁场不均匀度约束、5 Gs线范围约束、线圈区域最大磁场值约束和最大环向应力约束的条件下,获得用线量最少的线圈初始形状和位置,同时可以得到每个线圈的层数和每层匝数;通过遗传算法可以提高DSV区域的磁场不均匀度,以达到高质量成像的要求. 这种集成的优化设计方法既可以灵活有效的设计开放式MRI磁体,也可以设计传统的圆柱形MRI磁体,本文通过一个1.2 T的开放式MRI磁体的设计清楚的展示了这种优化方法. 关键词： 线性规划算法 遗传算法 自屏蔽 开放式超导MRI磁体     

A Magnet Field System for a High Density Tokamak Reactor

A design for a magnet system for a high density high field tokamak reactor is described. In this design stress in the trunk of the toroidal field structure is significantly reduced by elimination of the central ohmic heating transformer. In addition all superconducting coils are operated in the steady state and pulsed fields are generated only by copper coils.