兰州重离子加速器冷却储存环束流累积研究

对兰州重离子加速器冷却储存环加速器主体的主要功能环——主环的束流累积方法和设计进行了研究 .为了使主环对不同种类的重离子束流都具有较强的累积能力 ,在设计时考虑采用电子冷却参与下的两种束流累积方法 :多次多圈注入和射频堆积 .对这两种方法 ,电子冷却的冷却时间都是将束流累积到高流强的关键因素. The beam accumulation methods of HIRFL CSR(Heavy Ion Research Facility of Lanzhou and Cooler Storage Rings) project were studied. Two accumulation methods will be adopted to increase the beam intensity of CSRm. For both multiple multi turn injection method and RF stacking method, electron cooling of beam plays an important role.     

Effects of light intensity on reflective ghost imaging

In this letter, we analyze the effects of light intensity find that the brightness of reflective ghost image can on reflective ghost imaging with thermal source. We be changed by modulating the light intensity of the source and the splitting ratio of the beam splitter. The signal-to-noise ratio will be improved by increa.sing the light intensity of the source. More important, we can obtain the reflective ghost image with high image quality by adopting a low light intensity signal beam and a high light intensity reference beam, which is better than the classical optical imaging, because it can reduce the effects of light on the object.     

放射性次级束流分离器真空系统的压力分布

放射性次级束流分离器是强流重离子加速器装置中,连接增强器和高精度环形谱仪的束流输运线,用于传输重离子束流以及放射性次级束流。为了满足束流传输的要求,并维持相连增强器和高精度环形谱仪的极高真空,放射性次级束流分离器真空系统的平均压强应低于5×10-7 Pa。因此,需要验证真空系统设计方案的可行性,以及设计方案能否满足要求的压强范围。通过现有的同步储存环CSRm中的真空计监测数据以及软件BOLIDE的模拟结果对比,对真空压力计算软件VAKTRAK的使用方法和计算结果进行验证;采用VAKTRAK模拟计算不同真空参数下（流导、出气率以及泵速）放射性次级束流分离器真空系统的压力分布。根据计算结果,放射性次级束流分离器真空系统的平均压强可以达到1.79×10-7 Pa （H₂）,满足物理实验和工程设计的要求。通过模拟计算结果,放射性次级束流分离器真空系统的设计方案的可行性得到验证,系统设计的真空度满足要求。HIAF Fragment Separator(HFRS) is connected with Booster Ring(BRing) and Spectrometer Ring (SRing) in the HIAF and used to transfer the ion beams and radioactive secondary beams. To satisfy the requirements of beam transmission and maintain the extremely high vacuum of BRing and SRing, the average pressure of HFRS vacuum system should be lower than 5×10-7 Pa. Therefore, the feasibility of the design scheme and whether the design scheme would fulfill the required vacuum range or not should be verified. Based on the measured data on the current sychrontron CSRm and the simulation results of BOLIDE, the calculation results of VAKTRAK are verified and then VAKTRAK is used to calculate the pressure profiles of different parameters(such as the conductance, out-gassing and pumping speed) for HFRS. According to the calculation results, the average pressure of HFRS vacuum system could be 1.79×10-7(H₂) which achieves the required pressure for physics experiments and engineering design. According the calculation results of this paper, the feasibility of the designed HFRS vacuum system has been verified and the design of system satisfies the vacuum requirements.     

Long- and short-term average intensity for multi-Gaussian beam with a common axis in turbulence

With the help of the extended Huygens--Fresnel principle and the short-term mutual coherence function, the analytical formula of short-term average intensity for multi-Gaussian beam (MGB) in the turbulent atmosphere has been derived. The intensity in the absence of turbulence and the long-term average intensity in turbulence can both also be expressed in this formula. As special cases, comparisons among short-term average intensity, long-term average intensity, and the intensity in the absence of turbulence for flat topped beam and annular beam are carried out. The effects of the order of MGB, propagation distance and aperture radius on beam spreading are analysed and discussed in detail.     

强流ECR离子源引出系统研究

为了提高强流ECR 离子源的引出束流品质,分别设计了1# 和2# 引出系统,利用束流引出模拟软件PBGUNS 对1# 和2# 引出系统进行了质子束流引出与传输的模拟计算,结合实际测得的发射度数据分析引出系统,发现2# 引出系统比1# 引出系统引出束流品质高。对ECR 离子源引出系统的电势等位线分布等参数引起的球差进行了简单数学推导及MATLAB 绘图,并结合1# 和2# 引出系统束流相图模拟结果证明了球差会使引出束流品质有效发射度增长,通过适当加大电极孔径可改善束流聚焦情况,得到了束流光学聚焦较好的束流引出系统设计。To improve the quality of extracted ion beam from a high current ECR ion source, 1# and 2# extraction systems were designed and tested. The PBGUNS code was used to simulate the 1# and 2# extraction systems of proton ion beam. The emittance measurement results with the two different extraction systems were compared and analyzed with the simulation, the conclusion that more high quality beam extracted from 2# system than 1# system was got. The formula derivation of ECR ion source extraction system spherical aberration and MATLAB drawing was done by the analyzing on the distribution of extraction field equipotentials, effective emittance increasing caused by spherical berration was proved by 1# and 2# extraction systems beam phase space simulation result, beam focusing would be improved if electrode hole size increasing appropriately and a general concept on good optics focusing of ion beam extraction system was proposed finally.     

ADS注入器II的5 MeV高能传输线的设计与搭建

ADS先导专项的注入器Ⅱ计划在将质子束通过一个Cryomodule加速到5 MeV后,进行10 mA连续束流的调试,以验证ADS低能段的强流超导直线加速器技术。为了将50 kW的束流功率沉积到束流垃圾站,需要搭建一条高能束流传输线,从超导段开始传输束流。采用两套三组合四极透镜控制束流包络及垃圾站的束流尺寸,利用诊断真空室进行水平和垂直发射度的测量。为避免束流产生的真空管道损伤,该传输线必须确保束流无损失地传输到垃圾站。A CW 10 mA,5 MeV beam commissioning of CADS Injector Ⅱ is planed recently to test the high power superconduction linac techniques.To transport 50 kW beam from linac to the beam dump,a high energy beam line (HEBT) line is designed and setup.Two Triplet are used to control the beam size along HEBT and at the beam dump.One diagnostics box is used for horizontal and vertical emittance measurement.To avoid damages to the vacuum pipe,beam should be transported to the beam dump without losses.The details of the HEBT design will be described in the paper.     

金刚石探测器用于C-ADS注入器Ⅱ束损探测的模拟研究

加速器驱动次临界系统C-ADS 注入器Ⅱ采用强流超导质子直线加速器,设计流强达到10 mA。强流质子束产生的束流损失有可能损伤超导腔,需要专用的束流损失监测系统进行监测,束流损失探测器(BLM) 需要在高能量沉积导致超导腔失超之前提供警报。通过MCNPX 模拟计算10 MeV 质子在半波谐振腔(HWR)不同位置损失产生的辐射场,比较选取超导腔管道进出口处4 个位置为推荐束损探测器放置的位置,结合HWR腔结构和束损探测器选择的影响因素,计算了次级辐射在金刚石探测器中的能量沉积以及1° ~ 5°不同质子入射角度对探测的影响。结果表明,根据不同位置处探测器的能量沉积关系可以推断出束损点;不同入射角度不会影响生成粒子的能量分布,只轻微影响生成粒子的数目。The Chinese Accelerator Driven Subcritical System (C-ADS) injector II consists of super-conduction accelerating section which is half wave resonator (HWR), the designed beam intensity is 10 mA. To avoid the damage to the resonator due to proton beam loss, special Beam Loss Monitor (BLM) system is essential. BLM system could provide alarm signal when high energy deposition occurs which may cause the resonator quenching. Radiation field of 10 MeV proton lost at different point of the HWR are simulated with MCNPX, BLM could be set at proper positions based on the simulation. Considering the structure of HWR and the BLM detector selecting influence factor, radiation energy deposition in the diamond detector are simulated with MCNPX when the proton incidence angle change from 1°  5°, Possible beam loss point can be deduced from the relationship of energy deposition in detectors at different locations. The results indicate that energy spectra of secondary particles are independent with incidence angle; the number of secondary particles may be influenced slightly.     

Spatial beam shaping by quartz crystal piano-convex lens

Based on the optical activity of quartz crystal, we proposed a scheme for shaping the spatial intensity distribution of a linearly polarized laser beam by utilizing a quartz crystal piano-convex lens in combination with a polarizer. The intensity profile of the shaped laser beam can be easily switched from one profile to another by controlling the polarization direction of the incident laser beam.     

Spatial beam shaping by quartz crystal piano-convex lens

Based on the optical activity of quartz crystal,we proposed a scheme for shaping the spatial intensity distribution of a linearly polarized laser beam by utilizing a quartz crystal piano-convex lens in combination with a polarizer.The intensity profile of the shaped laser beam can be easily switched from one profile to another by controlling the polarization direction of the incident laser beam.     

束流强度探测变压器

兰州重离子加速器冷却储存环工程 (HIRFL CSR)主环和实验环上带电粒子束流强度的测量和监视拟由环型束流变压器实现 .通过对各种磁芯性能的分析和比较 ,束流变压器磁芯材料最终采用环形高磁导率超微晶合金 ,可测量束流脉冲的频率范围为 0 .2 - 2MHz .选择低噪声放大器将感应信号适当放大 ,可以实现对最小流强为 1μA束流的测量. The intensity of a pulsed beam of charged particles in the Cooling Storage Ring Project of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) will be measured with a toroidal current transformer. By comparing and analyzing the properties of kinds of magnetic cores, a strip wound toroidal core is adopted, which is made of a high-permeability alloy and can measure a pulsed beam with frequency range of 0.2 to 2 MHz. The permeability of Fe-based nanocrystalline alloy varying with frequency is measured...     

施特恩-格拉赫实验束形分析

对于施特恩-格拉赫实验,实验者通常是根据实验得到的束强分布与束强分布函数的符合程度来评价实验结果的．本文结合一系列专题实验,系统地讨论了束强分布函数的来源、基本形式、适用范围及应用时应注意的一些问题．     

洛伦兹-高斯光束在梯度折射率介质中的传输

导出了洛伦兹-高斯光束在梯度折射率介质中传输的光场分布,给出了二阶矩定义下的光束半宽度及其变化率的解析表达式,重点分析了梯度折射率系数对洛伦兹-高斯光束传输性能的影响。结果表明,梯度折射率介质中的归一化光强分布和光束半宽度等呈周期性变化,周期为梯度折射率系数的"倍,轴上最大光强出现在半周期处。梯度折射率系数除影响周期性外,对归一化光强分布和光束半宽度无明显影响,但影响光束半宽度变化率。     

HL-2A托卡马克中性束辐射光谱的数值模拟

采用数值模拟的方法研究中性束辐射光谱(BES)对开展与中性束相关的光谱诊断与实验有重要的指导意义.本文在HL-2A托卡马克装置上利用ADAS数据库（Atomic Data and Analysis Structure,1998）计算有效束辐射系数和有效束衰减系数,分析了束辐射光谱强度与等离子体运行参数和中性束参数的关系,并在不同的中性束注入能量、等离子体密度分布和等离子体温度分布的情况下,获得了束辐射光谱强度的空间分布.在n_e=2×10¹³ cm< 关键词： 中性束 束辐射光谱 束衰减     

Investigation of Elliptical Gaussian Beam in Optical Disk System

1.IntroductionLaserdiodehasbeenx`idelyusedinfibrc-opticcommunicat:onandopticaldisk$yctems.LaserbeamIsradiationangle(fullangu1aratha1f-maximumintensitypoint)ismeasuredbothparllelandPerpendiculartothcjunctionp1anclgenera1ly.o//=6,~1o",oJ-=2o"~5O':Inerasableopticaldisksystemsasmagneto-optica1disksystems,thelaserbcamiscollimatedandshapedtobecircularsymInetricbeaminordcrtoaquireahighintensityandhighqualityscanningbeamiPot,butitsoptica1systemiscomplicatedandeasyaddingassocialaberration.usingaellip…     

F-P干涉仪腔镜的不平行度对高斯光束透射特性的影响

基于多光束干涉原理,推导出了高斯光束经过两腔镜不严格平行的F P干涉仪后透射光强度的表达式。在此基础上,数值研究了F P干涉仪腔镜的不平行度对高斯光束透射特性的影响。结果表明:随着F P两腔镜不平行度的增大,透射光的峰值强度总体呈现下降的趋势,且在下降的过程中会出现波动;峰值强度位置将发生移动;光斑的均方根宽度将发生变化。     

产生多个高光强梯度局域空心光束的理论与实验

在实验中用贝塞尔光束与球面波叠加得到多个具有高强度梯度的局域空心光束(BB)。用衍射理论分析了贝塞尔光束与球面波叠加的光场,借助软件对两光场相干叠加的光强分布进行了模拟,结果表明在球面波的焦点附近能够形成多个高强度梯度的BB。实验中贝塞尔光束和球面波分别用轴棱锥和透镜对平行光聚焦获得,使两光场在同一传播轴上相干叠加,在球面波焦点附近观察到多个BB。通过对比可知,贝塞尔光束与球面波叠加所得BB比用两束贝塞尔光束干涉产生的BB在暗域处具有更大的光强梯度,更有利于稳定的粒子囚禁。     

Propagation of a phase-locked circular dark hollow beams array in a turbulent atmosphere

The propagation of phase-locked circular dark hollow beams array in a turbulent atmosphere is studied. An analytical expression for the average intensity distribution at the receiving plane is obtained based on the extended Huygens-Fresnel principle. The effects of turbulence, dark parameter and beam order of the beams array on the intensity pattern are studied and analyzed. It is found that the intensity pattern of the phase-locked circular dark hollow beams array will evolve from a multiple-spot-pattern into a Gaussian beam spot under the isotropic influence of the turbulence. The intensity pattern of beam array with a larger dark parameter and beam order evolves into the Gaussian-shape faster with increasing propagation distance.     

部分相干光对周期性局域空心光束的影响

用旋转毛玻璃和光阑把激光变成部分相干光, 再经过双轴棱锥系统把一束平行光变成两束同频率但不同径向波矢分量的无衍射贝塞尔光, 相干叠加产生了部分相干的周期性局域空心光束. 通过干涉理论与实验结果相互佐证, 得出局域空心光束的周期为2.5 mm. 进一步探究入射光场相干度对产生局域空心光束的影响, 发现随着相干度的降低局域空心光束中心暗斑与周围光强的衬比度会降低, 但不影响局域空心光束的周期以及中心暗斑尺寸.     

无衍射贝塞尔光束相干的理论与实验

 分别使用两种不同底角的轴棱锥产生无衍射贝塞尔光束。理论分析了单束贝塞尔光及两束贝塞尔光相干叠加后光场的光强分布,分析了产生的局域空心光束在一个完整周期内的特性。数值模拟了光沿纵向传播时光场的横向光强分布,并给出了相关的实验。对单束贝塞尔光及两束贝塞尔光干涉后的中心光斑的大小进行了测量,测量结果与理论计算结果吻合。     

Minimization of the fluctuation in the signal beam intensity of a nonlinear optical medium with a transmission grating

Fluctuation in the intensity of the output signal beam of a photorefractive optical resonator can be reduced significantly by employing pump beam positive feedback. The fractional intensity transfer which is independent of time in the absence of fluctuation becomes time dependent in the presence of fluctuation of the optical wave-mixing process. The influence of various controlling parameters on the relative fluctuation of the output signal intensity has also been studied.