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Study of Si K-shell X-ray emission induced by H+ and Ar11+ ions
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The L-shell X-rays of Si, induced by 50-250 keV proton and 1.0-3.0 MeV Ar11+ ions impacting are measured. It is found that the X-ray induced by Ar11+ is about 36 eV higher than that induced by proton. That indicates that 3, 4 L-shell electrons of Si atom are multiply-ionized by Ar11+ ion impact. The X-ray production cross section is extracted from the yield data and compared with the results from the BEA, PWBA and ECPSSR models. With the same unit incident energy, the cross section induced by Ar11+ is about 3 orders of magnitude larger than that produced by proton. For proton impact, the ECPSSR model gives an accurate prediction to the cross section data. However, the BEA model, considering the change of fluorescence yield due to the multiple-ionization, presents the results that are in better agreement with the experimental results for Ar11+ ions.</span
Charge state effect on the K-shell ionization of iron by xenon ions near the Bohr velocity
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe20+ are measured and compared with different binary-encounter-approximation (BEA) models. The results indicate that the BEA model corrected both by the Coulomb repulsion and by the effective nuclear charge (Z(eff)) agrees well with the experimental data. Comparison of Fe K-shell X-ray emission induced by 5 MeV xenon ions with different initial charge states (20+, 22+, 26+, 30+) verifies the applicability of the effective nuclear charge (Z(eff)) correction for the BEA model. It is found that Zeff correction is reasonable to describe direct ionization induced by xenon ions with no initial M-shell vacancies. However, when the M shell is opened, the Z(eff) corrected BEA model is unable to explain the inner-shell ionization, and the electron transfer by molecular-orbital promotion should be considered.</span
X-ray spectrum emitted by the impact of Eu-152(20+) of near Bohn velocity on Au surface
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The characteristic X-ray spectra produced by the impact of highly charged ions of Eu-152(20+) with energies from 2.0 to 6.0 MeV on Au surface are measured. It is found that highly charged ions could excite both the characteristic X-ray spectra of M-zeta, M-alpha and M-delta of Au and the characteristic X-ray spectra of M-alpha of Eu. The total X-ray yield increases with the ion kinetic energy increasing. The total production cross section of Au induced by Eu20+ is measured and compared with those obtained from the binary encounter approximation, plane-wave-Born approximation, and the energy-loss Coulomb deflection perturbed stationary state relativistic theoretical models.</span
A non-intercepting beam emittance measurement device based on neutral beam fluorescence method at PKU
No full text<span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 16px;">A new concept to attain ion beam emittance through measuring the forward neutral beam without intercepting the beam transportion was proposed at PKU. The forward neutral beam produced by space charge compensation and seperated from the transporting ion beam with the help of a deflecting magnetic field, carries the entire emittance information of the original particle beam and becomes a fast and non-interceptive beam diagnostic tool. This idea was tested on PKU ion source test bench and the experimental results show that the neutral beam fluorescence method is feasible. Based on these qualification results, a formal non-intercepting emittance measurement device was designed. It is a 90 degree full-scale dipole analysis magnet combined with the classical pepper-pot technique. Testing and commissioning of the device have been performed on the PKU test bench. Details of design and comnissioning results will be presented in this paper.</span
薄壁真空管道及由薄壁真空管道制造真空室的制造方法
No full text<span style="color: rgb(69, 69, 69); font-family: Arial, Helvetica, sans-serif; line-height: 21px; text-indent: 24px;"> 本发明主要涉及电真空设备的制造方法，尤其涉及一种可以在高频交流电场或交变磁场下使用的真空管道的制造方法。一种薄壁真空管道的制造方法，包括制管、卷边、设置加强筋等多个步骤，还提供一种由制成的真空管道制造真空室的制造方法，包括焊管、制造液压波纹管装置等工艺，用此工艺程序、参数和方法匹配制造出的薄壁真空管道，整个真空管道尺寸大、通体薄壁，能够满足在高频交流电场或交变磁场下使用要求。</span
用于抗辐射的药物及制备方法和应用
No full text<span style="color: rgb(69, 69, 69); font-family: Arial, Helvetica, sans-serif; line-height: 21px; text-indent: 24px;"> 本发明属于医药技术领域，具体涉及一种用于抗辐射的药物对人肺胚成纤维细胞、实验小鼠辐射损伤的保护作用。一种用于抗辐射的药物，具有4-甲氧基苯甲叉基-2-取代-5(4H)-噁唑酮及其衍生物的结构，可用结构通式(A)表示。本发明的优点是化合物(A)对于X射线、碳离子等电离辐射以及紫外线、微波等非电离辐射造成的人肺胚成纤维细胞(MRC-5)、实验小鼠的DNA和基因组损伤有显著的防护效果，可以显著提高上述射线照射后细胞的相对存活率、降低DNA损伤、降低基因组的不稳定性、降低小鼠脏器MDA产量、增强小鼠脏器SOD活性。毒性低，应用范围广，有良好的应用前景。</span
Dipole Field in Four Vane and Four Rod RFQ
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">RFQ (射频四极透镜)是直线加速器中最重要的前级聚焦加速结构,其工作模式下束流孔中的电场四极对称性是保证束流品质及加速效率的关键。为了解决其各自存在的工作模式下四极场的不对称问题,分别对四杆型RFQ和四翼型RFQ的结构和模式谐振特性做了研究。针对四翼型RFQ,模拟显示双端口对称耦合的方式从抵消二极模式和提高结构对称性两方面来达到削弱工作模式下的场分布中二极量的目的,对一个1 m段四翼RFQ模型腔的测量证实了双端口对称耦合抵消腔内二极模式的有效性;针对四杆型RFQ的二极场,以SSC-Linac项目的RFQ为原型,利用三维模拟计算软件CST-MWS进行模拟,通过改进支撑板的结构并调整参数,完全地消除了工作模式下的极间二极场,且理论上此种改进方法对支撑板结构的四杆型RFQ均有效。</span>Radio Frequency Quadruple(RFQ) is the most important front-end acceleration structure in linear acceler-ators. It can focus and accelerate beam in longitudinal and transversal direction, simultaneously. Symmetric of electric field in acceleration aperture is very important for the beam dynamics. To an idea RFQ, there is only quadruple electric field in the acceleration aperture. The dipole field in aperture is harmful and need be as small as possible. The methods to reduce it are studied in a four-rod RFQ and a four-vane RFQ in the article independently. To a four-vane RFQ, the symmetrical double-port couplers are employed to counteract the neighboring dipole modes. The availability is confirmed by the simulation with the 3-D Finite Element tool, CST-MWS. And it is also observed by measuring a model-cavity with a symmetrical double-port couplers. To a four-rod RFQ, a new structure of stems is proposed to reduce the dipole mode. Taking the RFQ for the SSC-LINAC project as example, the dipole mode contributions to the electric filed is completely eliminated by selecting stem's parameters carefully. It is confirmed by the simulation of CST-MWS. Theoretically, this method is independent with the frequency of an RFQ and serves for all RFQs with 4-rod or 4-wane structure.国家自然科学基金资助项
Research on the detuning system of a cooling electron beam for the dielectronic recombination experiment at CSRm
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">A storage ring equipped with an electron cooler is an ideal platform for dielectronic recombination (DR) experiments. In order to fulfill the requirement of DR measurements at the main Cooler Storage Ring, a detuning system for the precision control of the relative energy between the ion beam and the electron beam has been installed on the electron cooler device. The test run using 7.0 MeV/u C6+ beam was performed with recording the Schottky spectra and the ion beam currents. The influence of pulse heights and widths of the detuning voltage on the ion beam was analyzed. For the small pulse height, the experimental results from the Schottky spectra were in good agreement with the theoretical results. The frequency shift in the Schottky spectra was significantly reduced for the short pulse width. For the large pulse height, an oscillation phenomenon was observed and some effective ways to reduce the oscillation were pointed out. The detailed description of the phenomenon and the theoretical model based on the plasma oscillation is discussed in this paper. The overall results show that the new detuning system works properly, and could fulfill the requirements of future DR experiments.</span
Study of Si K-shell X-ray emission induced by H~+ and Ar~(11+) ions
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The L-shell X-rays of Si, induced by 50-250 keV proton and 1.0-3.0 MeV Ar11+ ions impacting are measured. It is found that the X-ray induced by Ar11+ is about 36 eV higher than that induced by proton. That indicates that 3, 4 L-shell electrons of Si atom are multiply-ionized by Ar11+ ion impact. The X-ray production cross section is extracted from the yield data and compared with the results from the BEA, PWBA and ECPSSR models. With the same unit incident energy, the cross section induced by Ar11+ is about 3 orders of magnitude larger than that produced by proton. For proton impact, the ECPSSR model gives an accurate prediction to the cross section data. However, the BEA model, considering the change of fluorescence yield due to the multiple-ionization, presents the results that are in better agreement with the experimental results for Ar11+ ions.</span