Physical design of a 10 MeV LINAC for polymer radiation processing

In China, polymer radiation processing has become one of the most important processing industries. The radiation processing source may be an electron beam accelerator or a radioactive source. Physical design of an electron beam facility applied for radiation crosslinking is introduced in this paper because of it’s much higher dose rate and efficiency. Main part of this facility is a 10 MeV travelling wave electron linac with constant impedance accelerating structure. A start to end simulation concerning the linac is reported in this paper. The codes Opera-3d, Poisson-superfish and Parmela are used to describe electromagnetic elements of the accelerator and track particle distribution from the cathode to the end of the linac. After beam dynamic optimization, wave phase velocities in the structure have been chosen to be 0.56, 0.9 and 0.999 respectively. Physical parameters about the main elements such as DC electron gun, iris-loaded periodic structure, solenoids, etc, are presented. Simulation results proves that it can satisfy the industrial requirement. The linac is under construction. Some components have been finished. Measurements proved that they are in a good agreement with the design values.     

W–band光注入器的模拟研究

模拟研究了1.6个腔、高梯度的W-band光阴极微波电子枪系统,该系统能产生和加速300pC的电子束团.设计系统由频率91.392GHz光阴极微波电子枪以及频率91.392GHz行波加速结构组成.基于射频直线加速器标度律与数值模拟结果,设计系统能产生能量1.74MeV,电量300pC,束团长度0.72ps,归一化横向发射度0.55mm·mrad的电子束团.研究了高频、高梯度下的束流动力学.由于高梯度,有质动力效应在束流动力学中起重要作用,且由于横向与纵向之间的耦合,在基次空间谐波的情形下,仍然存在着有质动力聚焦效应.     

S波段6 MeV边耦合电子直线加速器的设计研究（英文）北大核心CSCD

近年来,对紧凑、稳定及可靠型电子直线加速器的需求越来越多,其能量主要分布在几百keV到十几个MeV的范围内,其中需求最多的则是能量在MeV量级的微波电子直线加速器。在这种形势下,中国科学院高能物理研究所正在研制一台S波段6 MeV的边耦合电子直线加速器,本文对基于该加速器的模拟计算研究进行了介绍。EGUN和HFSS分别用来设计电子枪和边耦合加速结构。通过将EGUN计算得到的电子束流参数和HFSS计算得到的三维电磁场分布数据引入到PARMELA中,完成了对该加速器的多粒子动力学研究。模拟结果显示,所设计的加速器完全能够满足设计指标的要求。最终,在考虑束流负载效应的因素后,完成了边耦合加速结构的微波结构设计。     

CRRFA-30L波段射频加速器

 主要介绍CRRFA-30L波段射频加速器结构和性能，论述了热阴极射频腔注入器、束流加速系统、微波功率源和控制等结构中主要技术及其研究进展，给出了加速器输出束流参数测量与测量结果分析，达到设计应用要求。     

一种新型、紧凑、高效电子直线加速器加速管的设计研究

对一个新型、紧凑、高效的电子直线加速器的加速管的设计,进行了等阻抗与等梯度两种结构的比较研究.对于使用一个5MW速调管的能量和相位经过选择的用毕束流注入到两种加速管的情况应用Parmela程序进行了模拟计算.说明宜于加工和调试的等阻抗加速管更为适宜.最后,简单地讨论了如用更高功率(如30MW?,相应加速能量约为30MeV)的速调管用毕束流作为这种新型加速器的注入束时,等阻抗加速结构除了在设计、加工、调试中的简单易行外,同时模拟结果表明整个加速管无需外加横向聚焦磁场.     

C波段全密封加速管研制

 介绍了一台1.5MeV的C波段便携式无损电子直线加速器的全密封加速管的设计、微波冷测和研制,热测结果表明该加速管满足加速器的设计要求。     

100 MeV电子直线加速器的物理设计

 能量为100 MeV左右的高性能电子直线加速器是第三代同步辐射光源注入器和自由电子激光注入器的重要组成部分,采用热阴极栅控电子枪、聚束系统和4根SLAC型加速管作为加速器主体结构,一套45 MW的速调管调制器系统和波导系统作为微波功率源系统。设计中,使用了国际通用的模拟软件对加速器的动力学特性进行了数值模拟和参数优化,电子束能量达到100 MeV以上,能散小于1%,归一化发射度小于30 mm·mrad。     

Beam dynamics studies on the 100 MeV/100 kW electron linear accelerator for NSC KIPT neutron source

We designed a 100 MeV/100 kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the basis of subcritical assembly. Beam dynamics studies have been conducted to reach the design requirements (E=100 MeV, P=100 kW, dE/E<1% for 99% particles). In this paper, we will present the progress of the design and the dynamic simulation results. For high intensity and long beam pulse linear accelerators, the BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at a low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced downstream of the 1st accelerating section; the unwanted particles will be collimated there.     

TRIUMF ARIEL 电子直线加速器设计

 TRIUMF 的三期升级工程(ARIEL) 计划建造一个 50 MeV 平均流强为10 mA的电子直线加速器作为注入器,通过光裂反应生成放射性核素。电子直线加速器包括两个主要部分：注入器和后加速器,注入器完成电子能量从100 keV到10 MeV的转换,随后的后加速器将电子能量从10 MeV加速到50 MeV。电子源拟采用重复频率为650 MHz的热电子枪提供初始能量为100 keV,束长为 171 ps的电子束。束流动力学模拟了几种不同的设计方案以获得最优化的设计,模拟显示通过对腔体以及聚焦元件的仔细设计以及电子枪出射电子的参数选择, 电子束能量在达到50 MeV时束长可以被聚焦到 11.75 ps (对应于1.3 GHz 频率下5.5°) ,并且可以使电子束在超导低温柜中的尺寸保持在1.26 cm以下。     

Error analysis and lattice improvement for the C-ADS Injector-Ⅰ

The injector Scheme-Ⅰ (or Injector-Ⅰ) of the C-ADS linac is a 10 mA 10 MeV proton linac working in CW mode. It is mainly comprised of a 3.2 MeV room-temperature 4-vane RFQ and twelve superconducting single-spoke cavities housed in a long cryostat. Error analysis including alignment and field errors, and static and dynamic ones for the injector are presented. Based on detailed numerical simulations, an orbit correction scheme has been designed, which shows that with correction the rms residual orbit errors can be controlled within 0.3 mm and a beam loss rate of 1.7× 10^-6 is obtained. To reduce the beam loss rate further, an improved lattice design for the superconducting spoke cavity section has been studied.     

高俘获效率电子辐照加速器的设计研究

加速管是一台加速器的核心部分. 一般电子辐照加速器的俘获效率在50%左右, 一半的电子都损失在加速管内. 丢失的电子打在加速管内壁, 产生轫致辐射、腔体发热量增加、真空变坏等许多负面影响. 采用一段等梯度加速结构, 相速沿加速管呈线形增加,调整相速变化规律及加速管腔体的尺寸参数, 设计出的加速管最终的俘获效率提高到90%以上, 同时平均加速梯度没有因此降低, 加速管总长度没有增加.     

“神龙一号”直线感应加速器物理设计

 介绍了 “神龙一号”直线感应加速器物理设计的主要考虑。“神龙一号”加速器是一台电子直线感应加速器，由3.6MeV感应迭加型注入器、72个感应加速腔、脉冲功率系统、束流输运和聚焦系统、控制系统和真空、绝缘油、绝缘气体以及去离子水系统组成。能产生20MeV、束流大于2.5kA，脉冲宽度为60ns的强流脉冲电子束，X光焦斑均方根直径为1.5mm。     

医用质子加速器注入器7 MeV漂移管直线加速器的设计

 针对质子治癌直线加速器功耗少、长度短的要求,设计了一台工作频率为324 MHz的漂移管型质子直线加速器(DTL)。该DTL把粒子从2.5 MeV加速到7 MeV,功耗为265 kW, 总长1.9 m。横向聚焦采用FODO结构,漂移管内放置永磁铁。提出一种新的束流匹配方案,在射频四极场加速器(RFQ)与DTL之间不设束运线,而是以 DTL入口处的4个单元为匹配段,把RFQ出口处相椭圆匹配到DTL周期结构入口处的相椭圆。 用PARMILA程序对该DTL进行了动力学模拟,结果表明该方案的束流发射度增长很小。     

BEPCⅡ Positron Source

BEPCⅡ— an upgrade project of the Beijing Electron Positron Collider (BEPC) is a factory type of e^＋e^－ collider. The fundamental requirements for its injector linac are the beam energy of 1.89GeV for on-energy injection and a 40mA positron beam current at the linac end with a low beam emittance of 1.6μm and a low energy spread of ±0.5% so as to guarantee a higher injection rate (≥50mA/min) to the storage ring. Since the positron flux is proportional to the primary electron beam power on the target, we will increase the electron gun current from 4A to 10A by using a new electron gun system and increase the primary electron energy from 120MeV to 240MeV. The positron source itself is an extremely important system for producing more positrons, including a positron converter target chamber, a 12kA flux modulator, the 7m focusing module with DC power supplies and the support. The new positron production linac from the electron gun to the positron source has been installed into the tunnel. In what follows, we will emphasize the positron source design, manufacture and tests.     

医用质子直线加速器的设计研究

讨论用于治癌的低束流高能量质子直线加速器的初步物理设计.采用短脉冲和高重复频率的S波段的加速结构,类似于医用电子直线加速器.总长26m,由离子源、RFQ、DTL、SCDTL及SCL组成,能量经70—200MeV有八档可调,平均束流强度10—40nA.     

Physical design and cooling test of C-band standing wave accelerating tube

The physical design and cooling test of a C-band 2MeV standing wave (SW) accelerating tube are described in this paper. The designed accelerating structure consists of 3-cell buncher and 4-cell accelerating section with a total length of about 163mm,excited with 1MW magnetron. Dynamic simulation presents that about 150mA beam pulse current and 30{\%} capture efficiency can be achieved. By means of nonlinear Gauss fit on electron transverse distribution, the diameter of beam spot FWHM (full width at half maximum of density distribution) is about 0.55mm. Cooling test results of the accelerating tube show that frequencies of cavities are tuned to 5527MHz and the field distribution of bunching section is about 3:9:10.     

飞秒电子束装置的初步实验结果

 上海应用物理研究所建造并调试了一台飞秒电子束装置。这台装置主要由一把S波段热阴极微波电子枪、一台alpha磁铁和一根SLAC型加速管组成。这台装置可以产生能量为 20~30 MeV,峰值电流为100 A,微束团长度为250 fs的电子束。这篇文章报道了这台装置的调试和电子束团参数的测量。     

大功率辐照加速器的研制

介绍了10MeV/20kW大功率辐照加速器的设计. 该加速器采用返波型行波加速结构加速管, 综合了常规行波加速结构微波反射小、频率稳定性好和驻波加速结构分流阻抗高的优点. 加速器工作于S波段, 中心频率为~2856MHz. 利用自编的模拟程序AccDesign进行物理设计, 设计输出电子束能量为10MeV, 脉冲流强300mA, 加速管总长1.5m, 模拟计算结果显示微波至电子束的转换效率为66%. 同时利用计算机仿真程序对加速腔的温度和应力分布进行了计算, 得到了微波功率损耗对加速腔频率的影响.     

重离子治癌装置4 MeV/u IH型漂移管直线注入器的动力学设计

基于KONUS束流动力学理论,完成了一台工作频率为162.5 MHz、占空比为1%的交叉指型漂移管直线注入器（IH-DTL）的动力学设计。该IH-DTL内置两套三组合四极透镜,共有41个加速单元,可为同步加速器提供流强400 eμA、能量4 MeV/u的C4+束流。在动力学设计过程中着重对每个加速间隙的同步能量偏差、注入相位和间隙电压等参数进行优化,使得该IH-DTL的横向归一化RMS接收度达到0.24 πmm·mrad,且横纵向归一化发射度增长小于10%,有利于提高同步环的注入效率。然后根据动力学设计的结构参数进行IH-DTL的高频仿真计算,将得到的三维电磁场分布导入PIC粒子跟踪程序中进行束流动力学模拟。动力学模拟结果显示,束流在IH-DTL出口的横向自然发射度小于13 πmm·mrad,达到了同步环的注入要求,而且在7%的垂直二极场分量下,束流中心的横向偏移在±0.5 mm以内,整体的束流传输效率高于99%。An interdigital H-mode drift tube linac (IH-DTL) with KONUS beam dynamic has been designed, which operation frequency was chosen 162.5 MHz. This IH-DTL consists of 41 accelerating cells and two quadrupole magnets triplets, can provide the C4+ with the current of 400 eμA and energy of 4 MeV/u for the synchrotron. In the beam dynamic design, the synchronous particle energy, inject RF phase and the acceleration voltage of each gap are optimized carefully to make the transverse normalized RMS acceptance of the IH-DTL to be 0.24 πmm·mrad and the beam emittance growth small than 10%. Then the RF structure was designed and the 3D electromagnetic field was imported into the PIC particle tracking code for the beam dynamic simulation. The transverse beam emittance at the exit of the IH-DTL is small than 13πmm·mrad which meets the injection requirement of the synchrotron. What is more, under the 7% vertical dipole fields component, the offset between the beam center and the drift tube's axis is ±0.5 mm at most. The transmission efficiency of the IH-DTL is higher than 99% for the whole beam in the acceptance.     

IH型漂移管直线加速器的束流动力学研究（英文）

为了提高兰州重离子加速器冷却储存环（HIRFL-CSR）的运行效率、改善加速器输出束流品质,并实现几个加速装置分时供束,提高整个重离子加速装置的利用率,特为（HIRFL-CSR）增建一台新的注入器--CSRLINAC。在108.48 MHz的RFQ之后的CSR-LINAC主加速段,主要由一台108.48 MHz和两台216.96 MHz的IH型漂移管直线加速器组成,用于加速荷质比为1/8.5~1/3之间的重离子,其最大的束流流强为3 mA,并将粒子从0.3 MeV/u加速到3.71 MeV/u。运用KONUS动力学原理,在满足设计指标的情况下,首先利用TraceWin程序进行中能束线MEBT设计,后针对高频腔体设计和束流匹配的基本参数的系列讨论,特别是对CSR-LINAC的中能束流匹配线、参数选择和IH型KONUS结构的漂移管直线加速器进行设计模拟优化。最终得出,在保证腔体设计指标和95.3%的传输效率的情况下,该紧凑型直线加速结构经过三个腔体的加速后,束流的纵向归一化均方根发射度增长仅有25%;同时发现,当流强达到3 mA时,存在空间电荷效应,导致其纵向相宽增长约25%,最大横向包络也存在16.5%的涨落。In order to improve the operation efficiency of the Cooling Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR), a heavy ion linac (linear accelerator) was proposed and designed as a new injector for HIRFL-CSR. Following the 108.48 MHz Radio-Frequency Quadrupole (RFQ), three tanks in total with Interdigital H-mode drift tube linac (IH-DTL) structure are installed to boost the beam energy from 0.3 to 3.71 MeV/u, and the beam current of ions with charge-to-mass ratio from 1/8.5 to 1/3 can reach to 3 mA. The first tank operatesat the same frequency as the RFQ, and the rest two operate at 216.96 MHz. The “Combined Zero-Degree Synchronous Particle Structure” (KONUS) beam dynamics was used in the beam dynamics design. The overview of the physics design on the main accelerating components, including RF design and beam dynamics design are introduced in this paper. The optimized structure design, fabrication status and simulation results are presented in this contribution. It shows that under the condition of assurance of 95.3% transmission efficiency, the normalized rms emittance is about 25%. When the beam current is up to 3 mA, owing to the space charge effect, the increase of longitudinal phase spread and transverse envelope are about 25% and 16.3%, respectively.