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The status and improvement of the HIRFL-CSR operation software
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);">HIRFL-CSR is a new ion cooler-storage ring system in China's Institute of Modern Physics (IMP). This facility can accelerate all ions from protons up to the heaviest element, uranium, with variable energies for nuclear physics experiments, material irradiation research, and heavy ion particle therapy and so on. With the completion of this project, a new accelerator control system has been developed to accomplish the beam injection, accumulation, acceleration, extraction and manipulation. In this paper, the architectures of the HIRFL-CSR control system and timing system, the basic function of operation software, the data cycles of power supplies and the RF cavity are described in detail. Furthermore, to fulfill the requirements of special physics experiments and enhance the facility reliability, several operation software improvements, including eliminating the magnetic hysteresis effects, dipole magnets field slow feedback and super-period slow extraction, are also introduced in this paper. (c) 2012 Elsevier B.V. All rights reserved.</span
H ITFiL同步加速器剥离注入
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);">一台新的治癌专用加速器HITFiL正在设计和建造中,其中一台同步加速器为其主加速器,以高紧凑性、高可靠性和低成本为设计目标。同步加速器的注入系统采用剥离注入方式,剥离注入与单圈注入方式相比能达到较高的注入效率,而其造价明显低于多圈注入加电子冷却的注入方式。治癌采用碳粒子束,从 ECR离子源产生的C~95+离子经过回旋加速器预加速后在同步加速器注入点处剥离成为C~(6+)注入到环里。详细阐述了该注入系统的设计方案,并对整个注入过程进行了计算机模拟。在模拟过程中,对束流的注入效率、束流损失机制和粒子数增益进行了研究,得到了实空间和相空间的粒子分布和发射度增长趋势,得到了满足要求的束流流强。</span><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 new accelerator dedicated to hadron therapy, the Heavy-Ion Therapy Facility in Lanzhou (HITFiL), is under construction. As the main accelerator of HITFiL, a heavy-ion synchrotron is designed with special attention paid to compact structure, high reliability and low cost. Stripping injection scheme is adopted for the synchrotron, which is more efficient than single-turn injection and less costly than multi-turn injection supported by electron-cooling. Carbon beams are adopted for HITFiL cancer therapy: C~(5+) ions from an electron cyclotron resonance ion source, are pre-accelerated by a cyclotron, stripped into C~(6+) ions by a carbon foil located in a main dipole of the ring and injected into the central orbit of the ring at the same time. The detailed injection scheme for the synchrotron is presented, and the stripping injection process is simulated. The injection efficiency, complete beam loss factors and the particle number gain are investigated. In addition, beam properties including beam distribution in real and phase space and emittance growth due to foil traversal are studied, and the required beam intensity is achieved.</span
A CW high charge state heavy ion RFQ for SSC-linac
No full text<span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">To improve the super heavy ion beam injection efficiency and supply high current heavy ion beam for Separated Sector Cyclotron, A CW RFQ for heavy ion with high charge state has been designed and manufactured in the last two years. This RFQ will operate at 53.667MHz, will accelerate super heavy ions such as </span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">238</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">U</span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">34+</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> , </span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">208</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">Pb</span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">30+</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> and </span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">209</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">Bi</span><sup style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">30+</sup><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> to 143keV/u. This paper will introduce the SSC-LINAC components, especially the RFQ beam dynamics, full length structure design, tuning and cooling method. Furthermore RF system commissioning with full power will also be presented.(7 refs)</span>Asian Committee for Future Accelerators (ACFA); American Physical Society Division of Physics of Beams (APS-DPB); Chinese Academy of Sciences (CAS); European Physical Society Accelerator Group (EPS-A
Nanosecond pulse-width electron diode based on dielectric wall accelerator technology
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);">An electron diode using a short section of dielectric wall accelerator (DWA) has been under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. Tests have been carried out with spark gap switches triggered by lasers. The stack voltage efficiency of a four-layer of Blumleins reached about 6070% with gas filled spark gap switching. The generated pulse voltage of peak amplitude of 23 kV and pulse width of 5 ns is used to extract and accelerate an electron beam of 320 mA, measured by a fast current transformer. A nanosecond pulse width electron diode was achieved successfully. Furthermore, the principle of a DWA is well proven and the development details and discussions are presented in this article. (c) 2013 Elsevier B.V. All rights reserved.</span
Charge state distribution analysis of Al and Pb ions from the laser ion source at IMP
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 prototype laser ion source that could demonstrate the possibility of producing intense pulsed high charge state ion beams has been established with a commercial Nd:YAG laser (E-max=3 J, 1064 nm, 8-10 ns) to produce laser plasma for the research of Laser Ion Source (LIS). At the laser ion source test bench, high purity (99.998%) aluminum and lead targets have been tested for laser plasma experiment. An Electrostatic Ion Analyzer (EIA) and Electron Multiply Tube (EMT) detector were used to analyze the charge state and energy distribution of the ions produced by the laser ion source. The maximum charge states of Al12+ and Pb7+ were achieved. The results will be presented and discussed in this paper.</span
D P IS-RFQ系统的高频参数测试及功率锻炼
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);">中国科学院近代物理研究所于2007年开始进行等离子体直接注入项目的预研。详细介绍了RFQ系统的高频参数测试的方法及结果,并针对高脉冲功率的测试提出通过标定定向耦合器来测试脉冲功率的方法。介绍了系统锻炼的情况,包括针对功率源末级和腔内电极的打火问题提出了理论的分析和改善的方法。高频参数的测试和载束实验证实整套系统满足加速器的设计要求。</span><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 direct plasma injection scheme (DPIS) project has been developed since 2007 at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). In this paper, the test methods and results of radio frequency (RF) characteristics are presented, and especially a new approach, which can calibrate a directional coupler by the RF instrument, is introduced to measure the pulsed power precisely. Furthermore, we present the conditioning situation of the whole radio frequency quadrupole (RFQ) system including the analysis of and the solutions to the sparking of the cavity and amplifier. Finally, the result from the beam experiment proves that the design and measurement can meet the commissioning demand.</span
Structures and optical properties of Kr23+ and Ne8+-irradiated GaN epi-layers
No full textEpitaxial GaN layers grown by MOCVD on c-plane sapphire substrates were irradiated with 5.3 MeV Kr23+ and 2.3 MeV Ne8+ ions to various fluences. The pristine and the irradiated GaN samples were characterized using high resolution X-ray diffraction (HRXRD), UV-visible transmittance spectrum and Raman scattering spectrum analysis. The HRXRD results show an obvious increase in the FWHM and a decrease in the intensity of the GaN (0002) peak with increasing ion fluences. Meanwhile the UV-visible transmittance spectra show a decrease in the band gap value after irradiation. The Raman scattering spectrum shows that new Raman bands around 300 and 670 cm(-1) appear with increasing ion fluences. The new Raman bands can be ascribed to disorder-activated Raman scattering (DARS) from the highest acoustic-phonon branch and the optical-phonon branch at the brillouin zone boundaries, respectively. (C) 2013 Elsevier B.V. All rights reserved
小体积比两相分离早期过程的三维格子气模型研究
No full text<span id="ChDivSummary" name="ChDivSummary">采用Monte Carlo模拟方法研究了小体积比三维格子气模型中的相分离过程,比较了sc,fcc,bcc等3种晶格类型和T/Tc=0.45—0.85等5个相对温度的系统演化行为,计算了系统的结构因子函数,发现结构因子在相分离早期不满足标度关系,生长指数等于1/6,小于经典Lifshitz-Slyozov理论的值</span>The phase separation process in a three-dimensional lattice gas model with a low volume ratio c = 0.01 was studied. Using Monte Carlo simulation, the evolution behaviors of sc, fcc, bcc lattices, and 5 relative temperatures T/T-c = 0.45-0.85 were simulated. It was found that the structure factor functions did not satisfy the scaling relationship, and the growth index was 1/6, less than the value of Lifshitz-Slyozov theory
L-subshell X-ray intensity ratio of Xenon for 6 MeV Xe20+ impact on selected targets
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-ray emission of Xenon was measured for 6 MeV Xe20+ ions impacting on V, Fe, Ni, Cu and Zn targets. The distinct L-subshell X-rays and the energy shift were observed. The L-shell ionization and the multiple ionization of the outer-shell were investigated. In addition, the relative intensity ratios of L alpha(1,2) to L beta(1,3,4) and L beta(2,15) were obtained, which approximately decrease linearly with the increasing target atomic number. That was interpreted by considering multiple ionization of the outer-shell electron. (C) 2013 Elsevier B.V. All rights reserved.</span
Study of the data analysis process of the neutron wall with simulation
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);">We study the response function of the neutron wall for 300 MeV neutrons with GEANT4 simulations. The methods to find the correct neutron incident position and time are discussed, and the neutron emission angle and energy are reconstructed and compared with the simulation</span