快响应束流损失监控(FBLM)系统液闪探测器初样的研制

给出快响应束流损失监控(Fast Beam Lost Monitor,FBLM)系统的液体闪烁体探测器初样的研制.在高频四极加速器(Radio Frequency Quadrupole,RFQ)实验装置上的测试表明,液闪探测器能给出宽度为500 μs 束流宏脉冲结构,能逐个显示出宏脉冲内490 ns的束流切束脉冲.液闪...     

壁电流探测器在中国散裂中子源快循环同步加速器调束中的应用

快循环同步加速器（RCS）是中国散裂中子源（CSNS）的重要组成部分。负氢粒子束经直线加速器加速至80 MeV，剥离成质子束注入至RCS环并加速累积至1.6 GeV引出打靶。束流通过安装在RCS环的壁电流探测器（WCM）感应得到束流的强度信息，环高频与环主二极磁铁的失配会导致束流的实际振荡偏离理论预测。本文通过对WCM的数据进行分析得到了纵向工作点、束流的实际振荡频率、束团的电荷量、束团的形状变化等信息，方便了加速器的调束，并对参数测量中的测量误差进行了分析。     

透射电离室作为低能质子束流监测器的研究与应用

为有效监测低能质子的束流强度,研制了一种透射型电离室,用于HI-13串列加速器上低能质子束流的监测。研究了它的基本计量学性能,结果表明,各项性能均满足工作级电离室的要求。与传统的侧向束流监测用金硅面垒探测器测量结果相比,基于同向测量的透射电离室作为监测探测器明显优于金硅面垒探测器,提高了测量结果的准确度。     

BEPCII直线加速器发射度丝靶测量及软件开发

丝靶探测器是一种可以精确测量束流截面尺寸的装置。近年来,BEPCII在注入器末端安装了一组丝靶探测器,用来测量直线加速器出口的束流发射度,改进优化了束流截面和发射度测量计算的方法,提高了数据处理速度。同时,根据BEPCII丝靶测量流程,开发了发射度测量计算软件,实现了束流尺寸和发射度的实时在线测量,进一步提高了发射度的测量速度,为BEPCII的注入优化提供了参考。     

"预聚束器-斩波器"结构对慢正电子束流束团化的影响模拟

慢正电子湮没寿命谱测量是一种灵敏度高且可以无损探测材料微观缺陷的重要分析方法,束流束团化系统是实现该技术的核心部件,主要用来产生满足寿命测量时间分辨的束团并提供正电子产生的时间信号。本文选用Parmela程序,基于"预聚束器-斩波器"束团化系统,模拟计算了不同束流参数对150 ps(半高宽)束团化结果的影响并与"斩波器-预聚束器"束团化系统的计算结果做了对比,结果表明:提高束流能量、降低束流能散以及缩小束斑尺寸有利于提高束团化效率。数据显示:当束流能量≥500 eV、能散≤5 eV、束斑≤12 mm,"预聚束-斩波器"束团化系统的正电子利用率≥20%、聚束效率≥85%;且在相同束流参数下,"预聚束器-斩波器"束团化系统的正电子利用率要优于"斩波器-预聚束器"。     

多功能组合同步辐射束线光束探测器

光束探测器是同步辐射束线工程技术的重要组成部分,用以监测x光束线的位置、强度及空间分布等参数,因而对束线的准直、性能分析及实时监测具有重要意义。基于北京同步辐射实验室1W1B—XAFS束线工程项目,我们研制开发了一种应用光电二极管的光束探测器。该探测器与固定光阑、铍窗组合为一体,结构简单可靠,造价低,主要用于X光束线的准直及束流强度实时监测。1W1B—XAFX束线运行两年以来,探测器工作正常,达到了设计的目标。本文介绍了该种束流探测器的结构原理,及由此构成的一套完整的束流监测系统。同时也讨论了探测器的工作模式及测试结果。     

国家同步辐射实验室壁流探测器的研制

介绍了国家同步辐射实验室用于测量束流流强的壁流探测器，并分析了壁流流强小于束流流强的几种主要因素。最后给出了实际测量结果。     

基于CSNS壁电流探测器数据采集的定制示波器的研制

壁电流探测器是观测粒子加速器瞬时束流信息的一种重要手段。中国散裂中子源（CSNS）快循环同步加速器中安装了两个壁电流探测器，其中一个壁电流探测器用来测量束流的微脉冲信息。本文介绍了壁电流测量系统的硬件和软件，鉴于传统示波器在垂直分辨率及存储深度等方面的局限性，提出了一种定制示波器来进行壁电流的信息读取，并利用LabVIEW编程实现了20 ms内束流信息的宏脉冲读取及微脉冲结构的分析，使用同步的环高频信息分析能得出快循环同步加速器中双束团关于相位、圈数、每圈束团形状等方面的相关信息。     

束流漂移对硅条探测器阵列测量的影响

为研究束流漂移对结构紧凑、覆盖立体角较大的硅条探测器阵列测量的影响,利用蒙特卡罗方法,模拟了不同方向、不同大小的束流漂移对熔合蒸发残余核α衰变和卢瑟福散射角分布的影响,表明束流漂移距离小于3.0 mm时,探测器阵列的对称性能将计数误差控制在10%以下。开展了25 MeV和40 MeV ~6Li+~(209)Bi体系的实验测量,利用监视器数据研究了束流漂移的情况,结果表明,所有轮次的束流漂移均未超过3.0 mm。对束流漂移进行修正后,用3种不同的立体角刻度方法得到了弹性散射角分布,感兴趣的40 MeV数据与文献数据基本一致。     

束流漂移对硅条探测器阵列测量的影响

为研究束流漂移对结构紧凑、覆盖立体角较大的硅条探测器阵列测量的影响，利用蒙特卡罗方法，模拟了不同方向、不同大小的束流漂移对熔合蒸发残余核α衰变和卢瑟福散射角分布的影响，表明束流漂移距离小于3.0 mm时，探测器阵列的对称性能将计数误差控制在10%以下。开展了25 MeV和40 MeV ⁶Li+²⁰⁹Bi体系的实验测量，利用监视器数据研究了束流漂移的情况，结果表明，所有轮次的束流漂移均未超过3.0 mm。对束流漂移进行修正后，用3种不同的立体角刻度方法得到了弹性散射角分布，感兴趣的40 MeV数据与文献数据基本一致。     

合肥200MeV直线加速器的束流能谱测量系统

介绍了用分析磁铁，荧光靶，光学系统，光电二极管阵列和处理电路，示波器以及ＣＣＤ摄象系统构成的合肥２００ＭｅＶ直线加速器的束流能谱测量系统，并用该系统对２００ＭｅＶ束流能量和能散进行了测量，给出了测量结果。     

RESIDUAL GAS IONIZATION BEAM PROFILE MONITOR ON 40MeV H~－ BEAM TRANSPORT LINE

ＲＥＳＩＤＵＡＬＧＡＳＩＯＮＩＺＡＴＩＯＮＢＥＡＭＰＲＯＦＩＬＥＭＯＮＩＴＯＲＯＮ４０ＭｅＶＨ~－ＢＥＡＭＴＲＡＮＳＰＯＲＴＬＩＮＥＸｕＷｅｉｐｅｎｇ（徐伟鹏）（ＩｎｓｔｉｔｕｔｅｏｆＮｕｃｌｅａｒＲｅｓｅａｒｃｈ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙ...     

Computer investigation of ion beam optics for a Freeman type ion source system

The present work investigates the computer analysis of the ion beam properties produced by a Freeman type system. The extraction for such system is composed of four electrodes that permit to keep a fixed output energy by means of two accelerating gaps and one decelerating gap. The latter allows reducing the beam divergence angle. The combination of the acceleration/deceleration sections provides to keep a low beam emittance at the source outlet. The simulation of single charged argon ion trajectories for a plasma concave of curvature 4 mm was first studied with and without space charge effect using acceleration/deceleration extraction system with the aid of the SIMION computer program. The voltage applied to the accelerating electrode was optimized to accomplish the suitable ion trajectories without hitting the extraction electrode. Then, two additional studies were performed: the influence of the acceleration voltage and extraction voltage on the beam emittance and beam diameter; and the effect of the extraction gap width (distance between the plasma emission surface and the acceleration electrode) on the shape of the ion beam envelope and the position of the ion beam waist. Last, the influence of the space charge on the ion beam envelope was also investigated.     

电子直线加速器束截面测量系统及其应用

用于北京自由电子激光30MeV电子直线加速器的注入及输出束的截面监测系统,由可伸缩荧光屏束截面探头、摄象取样装置及图象采集卡和计算机处理系统构成。用此系统测量加速器注入(≤1.2MeV)和输出(≥20MeV)电子束的截面宽度、密度分布、发射度等参量。其硬件的空间分辨率好于110μm,束宽测量精度好于50μm。经加速器在线使用2年以上考验,性能可靠,得到了满意结果。     

Structural design of beam transport system in SGIII facility target area

Beam transport system in ShenGuangIII (SGIII) facility target area brings 48 laser beams from main laser output to final optics assemblies (FOAs). This paper will present a summary of structural design of SGIII target area beam transport system, which include 276 transport mirrors and nearly 3000 m beam enclosures. The key performance of the beam transport system structural design includes stability, accuracy and cleanliness. To ensure the vibrational stability requirement, the beam transport system is located on stable platforms comprised of switchyard steel space frame and experimental area steel reinforced concrete building. The high fundamental frequency of the transport mirror system and vibrational isolation from thin tubes are designed to decrease the vibration response of the mirrors. An analytical method is proposed to evaluate the structural design on the drifting error of each laser beam obtained by accounting the dynamic responses of each optical elements of laser beam. The adjusting and fast replacement online requirements are satisfied by the structural design of line replaceable units (LRUs), the adjustable kinematic mounts, and the low-stress clamping of mirror mounts. The cleanliness is established in the process of designing, fabrication, and operation simultaneously. Testing results of the beam transport system that has been installed indicate that the structural design satisfies the performance requirements of the facility.     

The effects of beam line pressure on the beam quality of an electron cyclotron resonance ion source

The results of a series of measurements studying the possibility to use neutral gas feeding into the beam line as a way to improve the quality of the heavy ion beams produced with an electron cyclotron resonance ion source (ECRIS) are presented. Significant reduction of the beam spot size and emittance can be achieved with this method. The observed effects are presumably due to increased space charge compensation degree of the ion beam in the beam line section between the ion source and the analyzing magnet. This is the region where the neutral gas was injected. It is shown that the effects are independent of the ion source tuning. Transmission measurements through the beam line and K-130 cyclotron have been carried out to study the effects of improved ion beam quality to the transmission efficiency.     

束流发射度和亮度与束流密度分布的关系

束流发射率和束流亮度是表征加速器束流品质的主要指标。理论和实验研究都已发现,它们与束流空间电荷的非均匀分布有密切关系。     

FEL中的束流发射度分析

根据自由电子激光器(FEL)对电子束流品质的要求,对束流发射度以及引起束流发射度变化的因素,诸如加速过程中微波场的突变、能量增加、波导结构的尾场效应和传输过程中的空间电荷效应、粒子密度分布的影响及偏转系统中的尾场效应等等,进行了物理上的分析,对其中某些情况,给出了束流发射度变化量的具体估算。     

Energy-spread measurement of triple-pulse electron beams based on the magnetic dispersion principle

The method of energy dispersion in magnetic field is used to analyze the energy spread of the triple-pulse electron beam generated by the Dragon-II linear induction accelerator.A sector magnet is applied for energy analysis of the electron beam,with a bending radius of 300 mm and a deflection angle of 90°.For each pulse,the time-resolved and integral images of the electron position at the output port of beam-bending line are recorded by a streak camera and a CCD camera,respectively.Experimental results demonstrate an energy spread of less than ±2.0%for the electron pulses.The cavity voltage waveforms obtained by different detectors are also analyzed for comparison.     

Beam dynamics study for a small, high current 14 MeV PET cyclotron

A 14 MeV high intensity cyclotron CYCIAE-14 dedicated to Positron Emission Tomography (PET) is under construction at China Institute of Atomic Energy (CIAE). Based on a set of basic technical requirements for the accelerator and its extracted beam, the cyclotron beam dynamics were studied and the results are presented. Static beam dynamics, beam motion inside the machine under imperfection conditions and beam behavior in the extraction process were also investigated. This work gives an in-depth view of the beam dynamics study, numerical simulation as well as the corresponding results and necessary analyses.