BEPC横向阻尼时间的测量

 利用逐束团测量系统在BEPC储存环中跟踪单个束团得到其多圈位置振荡信息，获得BEPC储存环的横向阻尼时间与束流流强、色品、八极子和束流能量的关系，并通过分析得到了BEPC储存环辐射阻尼时间为52 ms。实验结果表明：流强越高、色品越大，阻尼率也就越大；束流流强为4.7 mA时八极子强度的变化对阻尼率没有影响；束流流强为5 mA时，阻尼率随束流能量升高而减小。     

合肥储存环二期改造工程的调试

合肥光源二期工程改造后, 对电子储存环光学参数进行了全面的调试和测量, 新注入系统和高频系统的调试, 也获得了巨大的成功, 在插入八极铁和过正地补偿色品后, 耦合束团不稳定性的得到了有效地抑制, 从而使改造后电子储存环能积累和运行在300mA以上的流强.     

合肥电子储存环束流不稳定性的抑制

 合肥光源二期工程改造的电子储存环调试过程中,发现多束团存储和运行时存在耦合束团不稳定性,严重地限制了注入的最高流强,并且影响了光源运行的质量。通过过正地增大正色品以及在储存环上插入八极磁铁,基本上抑制了横向的耦合束团不稳定性,保证了稳定注入束流300 mA的技术指标。     

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.     

FEL光学速调管的升级性能分析

通过三维磁场的有限元计算,给出了自由电子激光（FEL）研究用光学速调管升级后的磁参数。国家同步辐射实验室合肥光源（HLS）电子储存环能量可以日常运行在200～800 MeV间,为了与电子储存环能量匹配,并在较高束电子能量下进行实验和得到较多的相干辐射光子,光学速调管从原来的对称结构升级成非对称结构,用于HLS储存环谐波产生FEL实验。给出了升级后非对称光学速调管的几组匹配磁参数,用于在HLS储存环注入能量和可以运行的最高能量下进行谐波FEL实验。初步计算表明,HLS 储存环电子束性能优越,能散很低,FEL实验用最高能散仅为2.05×10-4,相应FEL辐射的能散修正因子在0.96以上,可以忽略不计。     

合肥光源电子束流能量标定的前期研究

为了在合肥储存环上利用共振退极化的方法建立一套测量电子束能量的装置, 进行了物理计算,     

BEPCⅡ中电子云不稳定性模拟研究

正电子储存环在多束团运行时有可能发生电子云不稳定性(ECI)?.本文针对北京正负电子对撞机二期工程(BEPCⅡ)的具体条件,编写发展了模拟计算程序,以不同电子云密度抑制措施下的计算结果为基础,研究了耦合束团不稳定性和单束团不稳定性,给出了电子云不稳定性增长率和阈值密度以及色品对束团尺寸增长的抑制作用,为储存环中电子云不稳定性的前沿科学研究和BEPCⅡ工程设计提供了有意义的结果.     

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。     

北京正负电子对撞机重大改造工程储存环调试运行期间辐射剂量监测与分析

介绍北京正负电子对撞机重大改造工程储存环加速器调试运行期间周围环境、工作区域各监测点的平均辐射剂量率水平.给出了电子环调试、正电子环调试、正负电子双环对撞调试、同步辐射光用户实验及不同束流频率下的典型剂量率水平曲线图,并提出了防护建议.总体监测数据表明,储存环调试运行期间,主体屏蔽及局部防护措施满足了储存环加速器调试运行需要,达到了设计指标.     

直流清洗电场对储存环聚焦参数修正作用的研究

研究了直流清洗电场对储存环聚焦参数的修正作用.认为该清洗电场形成的横向振荡数移位,与储存束流闭轨实时位置有关.指出电极沿环不对称分布的此类清洗电场,会破坏储存环聚焦结构的对称性,降低储存环的接受度,在一定条件下,对注入积累束流过程有负作用.     

New chromaticity compensation approach and dynamic aperture increase in the SSRF storage ring

Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find solutions that provide large dynamic apertures. This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure, which is applied in the SSRF storage ring, and a better solution is obtained. Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory.     

New chromaticity compensation approach and dynamic aperture increase in the SSRF storage ring

Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically.Many optimization methods can be used to find solutions that provide large dynamic apertures.This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure,which is applied in the SSRF storage ring,and a better solution is obtained.Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory.     

上海质子医疗装置的涡流效应

 涡流效应是较快重复频率加速器必须考虑的问题。涡流效应引入的六极、四极、二极分量,以及发热效应都会对环的参数如色品、工作点、共振、能量漂移等产生影响。通过计算引入不同效应的强度,模拟了各种效应对环参数的影响,并针对不同升能曲线和升能频率引入涡流效应的计算和比较,得出了在目前考虑的频率范围内,对主环影响较大的效应为六极场,其它效应的影响需要较大的重复频率。并以此为依据选择了最终的工作曲线为半正弦,上升时间为0.7 s。     

Measurement of optics for the SSRF storage ring in commissioning

The Shanghai Synchrotron Radiation Facility (SSRF) is a low emittance third-generation synchrotron radiation light source. Some optics parameters of the storage ring were measured when commissioning. This report presents the common methods for measuring some optics parameters of the storage ring, including the betatron tune, beta function, chromaticity, natural chromaticity and dispersion. The results and analysis of measurement for the optics parameters are given here, which are indispensable for the orbit correction of the accelerator and the nonlinear optimization.     

Measurement of optics for the SSRF storage ring in commissioning

The Shanghai Synchrotron Radiation Facility (SSRF) is a low emittance third-generation synchrotron radiation light source. Some optics parameters of the storage ring were measured when commissioning. This report presents the common methods for measuring some optics parameters of the storage ring, including the betatron tune, beta function, chromaticity, natural chromaticity and dispersion. The results and analysis of measurement for the optics parameters are given here, which are indispensable for the orbit correction of the accelerator and the nonlinear optimization.     

多束团模式下束流位置频谱模型及参数获取算法

以储存环逐圈位置频谱模型为基础,通过一些假设条件推导出多束团模式下束流位置的频谱模型。利用上海光源储存环受激多束团位置信号频谱数据,使用遗传算法进行多曲线数据拟合得到模型参数。结果表明:在迭代100次的条件下,该模型与原数据所有曲线的相关性均在95%以上,并且可以精确估计多束团频谱曲线的双峰分裂。曲线拟合后的参数可以监测储存环阻抗的变化。     

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.     

Orbit response matrix analysis and lattice periodicity restoration of the SSRF storage ring

In this paper, we present numerically and experimentally the linear beam-optics distortion in the SSRF storage ring and the correction of optics by using a number of quadrupole magnets installed in the storage ring. The measured orbit-response matrices were fitted to the model-response matrices to obtain the β and the dispersion functions in the storage ring. By readjusting the currents of quadrupole-magnet power supplies, we were able to successfully restore the optics parameters to values very close to the design ones, with rms deviations around 1%. This periodicity restoration is verified with the β function measurement,     

用于太赫兹光源的准等时性储存环的设计

介绍了一种获得准等时性储存环的方案,即调节Lattice参数,在色散段引入负色散函数从而降低线性滑相因子,获得短束团。根据此方案设计了用于相干太赫兹光源的准等时性储存环,结果给出了线形光学函数曲线以及粒子的动力学孔径,表明了通过调节四极铁参数可以达到降低束团长度获得准等时性储存环的目的。还设计了用于准等时性储存环弯铁处的真空室的3维模型,并对其类腔体部分的本征模进行了计算,得到特性阻抗与品质因数的比值在10-3量级以下,表明类腔体部分对束流的影响很小。