一种基于伸展线法的小孔径四极磁铁测量方法

针对目前多极磁铁孔径越来越小的发展趋势，搭建了一种基于单根伸展线法(Single Stretched Wire Method,SSWM)的磁测系统，该系统的主要优势是测量域所需空间小且运动模式灵活。基于该系统的优势及四极磁铁磁场分布的特点，尝试使用双曲线轨迹对四极磁铁靠近其四个极头的区域进行了扫描测量，并根据矢势在测量点分布的特性，提出了一种全新的数据分析方法，用以分析四极磁铁的梯度积分和高阶场误差。用该系统对一孔半径为11 mm、梯度大于100 T·m^-1的四极磁铁进行测量，测量结果表明高阶场误差测量重复性好于±1.5×10^-4，能满足小孔径高梯度四极磁铁的磁场测量要求。     

脉冲四极磁铁峰值梯度测量

一、测量原理质子直线加速器中的漂移管四极透镜是由近似半正弦波的脉冲电流励磁的。脉冲底宽约为3.5毫秒,重复频率为每秒10次。四极透镜孔径内的磁场,若只考虑其空间分布,它是中心为零的梯度场,如图1所示。图中B_y、B_x分别表示磁场在y和x方向的分量。     

CYCIAE-30医用回旋加速器束流输运系统升级改造

在中国原子能科学研究院CYCIAE－30医用回旋加速器现有的束流输运系统的基础上，根据气体靶生产新品种医用同位素的技术要求，用TRACE－3D对束流输运系统的升级改造方案进行设计，包括束流线的总体布局和光学设计。根据束流光学设计的结果，〖JP3〗设计了新增束流线的磁四极透镜和偏转磁铁。     

BPL 750 keV束流输运线上四极磁铁的设计

一、引言自从北京质子直线加速器的10 MeV段1982年底出束以来,于1985年已将其能量扩展到35 MeV,脉冲流强达到70 mA,作为从高压倍加器至质子直线加速器之间的750 keV束流输运线,经历了10 MeV和35 MeV两个阶段的调试和运行。它有效地将质子束流从高压倍加器输运到直线加速器,传输效率达到设计指标。本文介绍安装在这一束流输运线上的四极磁铁的设计、磁场测量结果及实际运行情况。     

电子储存环扭摆磁铁效应的一种补偿方法

本文介绍BEPC储存环插入一块高场水平扭摆磁铁情况下一种可能的补偿方法。利用位于扭摆磁铁附近消失差区域中的由独立电源供电的四块四极磁铁,按Twiss参量重新匹配的要求改变其强度,在扭摆磁铁和四块四极磁铁所在区域及其以外区域,均可获得Twiss参量补偿的满意结果。     

射频四极场加速器低能强束流传输注入系统的实验研究

对加速器驱动的次临界系统（ADS）的射频四极场（RFQ）加速器的低能强流束流传输系统进行实验研究,给出了在强流离子束束腰附近测量束流参数的方法,并测量了强流质子注入系统在RFQ入口处的束流参数。目前,该系统已成功地应用于强流射频四极场质子加速器中。     

两种测量氚靶3He释放方法比较

对开放式离子源四极质谱计和封闭式离子源四极质谱计实验装置进行了标定,并用其对氚靶中3He释放进行了测量.标定与测量结果表明开放式离子源四极质谱计可定量测量3He的最低原子数为6×106,封闭式离子源四极质谱计则为3×1010;对于氚量较大的氚靶,两者均能对其3He释放进行定量测量,测量结果间的相对偏差约为5.3%;对于小氚量氚靶,前者可用于3He定量测量,测量结果的不确定度主要来源于质谱计的标定过程,约为7.2%,后者则难以对其进行定量测量.     

PSC/PSI电源控制器在BEPCII样机电源中应用研究

BEPCII储存环的磁铁电源系统、按磁铁种类及供电方式,分为B铁电源、Q铁电源、S铁电源、斜四极子电源、校正磁铁电源、超导磁铁电源、同步辐射插入件4W1电源。由于储存环磁铁电源需要重新设计,并且数量由原来的97台增加到350台左右,所以储存环磁铁电源控制系统需要重建。为保证较高的控制精度和提高系统的抗干扰能力,采用美国SNS实验室研制的电源控制器(PSC／PSI)。介绍了PSC／PSI电源控制器在BII样机电源中应用,解决了接地的规范问题,避免了各种干扰。     

直通道磁元件磁场测量

为使重离子束从注入器（ＳＦＣ）不经主加速器（ＳＳＣ）直接传输到实验终端。最近在兰州重离子研究装置（ＨＩＲＦＬ）上新建了直通管道系统。在该系统中有３台偏转磁铁和３台四极透镜。本文叙述了它们的测磁内容和方法，给出了激磁曲线、径向和轴向场分布、磁场梯度、等效长度等结果。结果表明：全部符合原设计要求，并有一定的余量。     

HLS脉冲四极磁铁注入方法设计与研究

介绍了一种采用脉冲四极磁铁实现储存环束流注入的新方法.通过物理计算和注入过程数值模拟研究,确定了储存环上安装脉冲四极磁铁的位置和强度,并通过模拟计算评估了注入过程中注入束流存活效率和对储存束流的影响,证明了在合肥光源采用脉冲四极磁铁完成束流注入过程的可行性.     

Measurement and Research of Beam-Based Alignment With AC k-Modulation at HLS

A new beam-based alignment (BBA) measurement system with AC k-modulation module was developed recently at Hefei Light Source (HLS), which equipped the quadrupole magnets on the storage ring with a current shunt system which was able to vary the magnet current of a given quadrupole at a given frequency. The corresponding closed orbit oscillation amplitude measured for different beam positions in the quadrupole reached a minimum when the beam was centered in the quadrupole. Amplitude estimation algorithms of software lock-in amplifier and interpolated FFT were discussed. A V-shaped curve was used to determine the offset; a method using a parabola fit to determine the offset was also discussed. This BPM-to-quadrupole offset was determined at HLS with an accuracy of ~50 mum. The reproducibility of the beam based alignment using this technique is about 20 mum (RMS)     

Methods of measurement for the beam-based alignment system in HLS

The beam-based alignment system is given in HLS （Hefei Light Source）, in which a switchable shunt resistor was installed on quadrupole to bypass a small percentage of the magnet current. The system can measure BPM-to-quadrupole offset which can be used to position the beam in the magnetic center of quadrupoles. In measurement, some methods （ linear fitting with single corrector, parabola fitting with single corrector, linear fitting with local bump, and parabola fitting with local bump ） are used. These measurement results are given, and compared among the methods mentioned above.     

Cl/S isobar separation using an on-line reaction cell for 36Cl measurement at low energies

A radio-frequency quadrupole ion guided reaction cell, incorporated into a system for generating, decelerating and accelerating anions for analysis by accelerator mass spectrometry is described. Tests of this system for the suppression of the unwanted isobar ³⁶S in the analysis of ³⁶Cl and the measurement of a standard ³⁶Cl reference material are reported.     

ITALIAN MONEY TESTED FOR FORGERY BY MOSSBAUER SPECTROSCOPY

Italian money has been investigated by Mossbauer spectroscopy. The results indicated that the spectrum of a 10000 lire bank-note consisted of three magnetic sextets and two quadrupole doublets, the spectrum of a 50000 lire note consisted of two Zeeman sextets, but in the "false" money there are two quadrupole doublets only.     

一种波荡器段间四极铁远程精密调节机构的研制

自由电子激光(Free Electron Laser,FEL)装置是一种以相对论高品质电子束作为工作介质,在周期磁场中以受激发射方式放大电磁辐射的新型激光源。FEL装置中的四极铁中心相对于束流中心线的高精度就位与否将直接影响束流的品质,上海软X射线自由电子激光装置和大连极紫外相干光源装置的波荡器段间四极铁均采用基于束流准直方法(Beam based alignment,BBA),需要可远程精密调节四极铁位置的机构。BBA四极铁远程精密调节机构主要由可远程精密定位的电移机构和控制系统构成。电移机构采用精密滚珠丝杠驱动的滑块组合机构,可实现垂直于束流的水平和竖直高度方向的二维调节。本文简单描述了BBA四极铁远程精密调节机构的机械设计,对BBA四极铁远程精密调节机构的测试方法及结果进行了详细分析。该系统集成测试结果表明,机构运动过程中采用光栅尺进行反馈,其定位精度和重复性均达到了设计指标要求。     

Development of a tune knob for lattice adjustment in the HLS-II storage ring

The betatron tune is an important parameter in a storage ring to enable stable operation. A tune adjustment tool with a small impact on the beam dynamics is useful for user operation and machine studies. Therefore, a tune knob is developed for the Hefei light source-II(HLS-II) storage ring. Owing to the compactness of the storage ring, a global adjustment mechanism is adopted. To reduce the impact on beam injection, only quadrupole families outside the injection section are used by the tune knob, and the b functions of the injection section remain unchanged. A code is developed based on the accelerator simulation software, MAD-X, to calculate the adjustment of the quadrupole strengths. The accelerator toolbox is used to double check the accuracy of the tune knob. Online measurement of the tune knob is also performed. The result shows that the tune knob works well when the tune is adjusted in a specific range. Betatron coupling measurement is also carried out, showing an application of the tune knob on machine studies. In this paper, the development of the tune knob and its experimental results in the HLS-II storage ring are reported in detail.     

Linear Accelerator for Multiply-Charged Ions at 8 MeV/nucleon – Injector in the TWA Accelerator Complex

The terawatt accumulator at the Institute of Theoretical and Experimental Physics is in the physical startup phase. A new high-current linear accelerator-injector must be developed to achieve design parameters 10¹¹ particles/sec on target; this injector should give at the entrance of the accelerator ring a heavy-ion beam with current 15–20 mA and energy ~7–8 MeV/nucleon with the required charge-to-mass ratio. To this end, a linear accelerator with rf quadrupole focusing at the working frequency 81 MHz was developed; it will accelerate Al¹¹⁺ or Co²⁵⁺ from a laser source before the synchrotron. The accelerator will consist of two sections. The first section with spatially uniform quadrupole focusing will accelerate the beam up to 1.6 MeV/nucleon. A new structure with rf quadrupole focusing and period length 2 is proposed for the second accelerating section. Preliminary numerical simulation of this structure showed that 7 MeV/nucleon with minimum beam losses and accelerating gradients 3.5 MV/m will be achieved on it. Construction of the first section with spatially uniform quadrupole focusing has begun.     

Multipole lenses and their application in nuclear microprobe lens systems

In principle, aberrations of nuclear microprobe lens systems can be corrected with multipole lenses. This paper discusses multipole lenses and how they may be used to correct divergence dependent aberrations in a quadrupole probe forming lens system. Also discussed is the grid shadow method which provides a practical means for experimental study of the properties of the multipole lenses as well as a potential means for adjustment of the multipoles to achieve correction. Results are presented showing the effect of sextupole, octupole and duodecapole lenses in simplified lens systems that consisted of a single magnetic quadrupole and a single magnetic multipole. Further results are presented that show the grid shadow method applied to the magnetic quadrupole Russian quadruplet of the Melbourne Proton Microprobe. In this case the system was found initially to suffer from large parasitic aberration, probably octupole, which was later significantly reduced by replacement of some damaged pole tips.     

Transport of Intense Ion Beams

The possibility of using intense bursts of heavy ions to initiate an inertially confined fusion reaction has stimulated interest in the transport of intense unneutralized heavy ion beams by quadrupole or solenoid systems. We have examined this problem in somne detail, using numerical integration of the coupled envelope equations for the quadrupole case. The general relations which emerge are used to develop examples of high energy transport systems and as a basis for discussing the limitations imposed by a transport system on achievable intensities for initial acceleration.