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Evaluation of KTJT-1, an early-maturity mutant of sweet sorghum acquired by carbon ions irradiation
No full text84 MeV C-ions irradiation effects on Zr-45Ti-5Al-3V alloy
No full textNewly developed Zr-45Ti-5Al-3V alloy were irradiated by 84 MeV carbon ions with doses of 4 * 10(15) ions/cm(2) and 12 * 10(15) ions/cm(2), respectively. XRD, SEM, TEM, SAD and tensile tests were performed to study the microstructural evolution and mechanical properties modification upon high energy carbon ion irradiation. XRD patterns show no phase change while the diffraction peak position and intensity vary with irradiation doses. Tensile tests verify monotonic change of alloy strengths and elongations upon irradiation. Microstructure observations of the irradiated samples reveal the irradiation-induced precipitation of (Zr,Ti)(3)C-2, which was believed contributing to the alloy hardening. Superlattice was discovered by the SAD patterns of original and irradiated samples and the high energy C-ions implantation was demonstrated to promote the disorder-order transition by introducing lattice defects. (C) 2014 Elsevier B.V. All rights reserved
Mitotic DNA damages induced by carbon-ion radiation incur additional chromosomal breaks in polyploidy
No full textCompared with low linear energy transfer (LET) radiation, carbon-ion radiation has been proved to induce high frequency of more complex DNA damages, including DNA double strands (DSBs) and non-DSB clustered DNA lesions. Chemotherapeutic drug doxorubicin has been reported to elicit additional H2AX phosphorylation in polyploidy. Here, we investigated whether mitotic DNA damage induced by high-LET carbon-ion radiation could play the same role. We demonstrate that impairment of post-mitotic G(1) and S arrest and abrogation of post-mitotic G(2)-M checkpoint failed to prevent mis-replication of damaged DNA and mis-separation of chromosomes. Meanwhile, mitotic slippage only nocodazole-related, cytokinesis failure and cell fusion collectively contributed to the formation of binucleated cells. Chk1 and Cdh1 activation was inhibited when polyploidy emerged in force, both of which are critical components for mitotic exit and cytokinesis. Carbon-ion radiation irrelevant of nocodazole incurred additional DNA breaks in polyploidy, manifesting as structural and numerical karyotype changes. The proliferation of cells given pre-synchronization and radiation was completely inhibited and cells were intensely apoptotic. Since increased chromosomal damage resulted in extensive H2AX phosphorylation during polyploidy, we propose that the additional gamma-H2AX during polyploidy incurred by carbon-ion radiation provides a final opportunity for these dangerous and chromosomally unstable cells to be eliminated. (C) 2014 Elsevier Ireland Ltd. All rights reserved
Design of Control System for High Intensity Proton RFQ Based on Redundancy Technology
No full text中国科学院近代物理研究所研制了一台用于ADS注入器Ⅱ的强流质子RFQ加速器。相对于常规功率源,用于RFQ腔体的功率源的控制精度要求更高、过程更复杂。控制系统需通过精确的水温控制实现频率调谐,水温的控制和监测精度要求为0.1℃。同时,为避免腔体因局部温度过高而损毁,控制系统必须实现实时的温度监测和可靠的联锁保护功能。为此,基于EPICS控制架构设计了RFQ控制系统,对关键控制代码的运行平台采用高性能冗余控制器,开发了具有网络冗余功能的IOC驱动程序,实现了水温联锁保护及高频系统控制。RFQ控制系统经现场测试,通信正常、运行稳定,冗余系统的主备切换时间在ms量级,满足RFQ腔体的控制要求。.A high intensity proton RFQ accelerator for injectorⅡof China ADS project was developed at Institute of Modern Physics,Chinese Academy of Sciences.Compared with RF power source for conventional accelerator,the control accuracy of power source for RFQ is much higher and the control processing is more complicate.Frequency tuning was achieved by water temperature control in the control system and the control accuracy can reach 0.1℃.Besides,to avoid the RFQ cavity from thermal damage,it is necessary to complete temperature monitoring and interlock protection at any time.For these reasons,the RFQ control system was designed based on EPICS framework.High performance redundant controller was used in operation platform with key control code. IOC drivers with network redundancy were developed,and the control of interlock protection and RF system were realized.Through the test on the spot,the control system can communicate successfully and operate stably.For the redundant system,the switching time is in the order of millisecond,which satisfies the requirement of RFQ cavity control
Large scale particle tracking and the application in the simulation of the RFQ accelerator
No full textX-ray spectrum emitted by the impact of ~(129)Xe~(26+) of the different kinetic energies 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 Xe-129(26+) with kinetic energies from 350 to 600 keV and from 1.8 to 3.9 MeV on Au surface are measured. It is found that Xe-129(26+) with kinetic energies from 350 to 600 keV can excite only the characteristic X-ray spectra of M alpha of Au, but Xe-129(26+) with kinetic energies from 1.8 to 3.9 MeV can excite the characteristic X-ray spectra of M zeta, M alpha, M gamma and M delta. The relation between the characteristic X-ray intensity, the ratio of X-ray yield and the ion kinetic energy is analyzed. The kinetic energy threshold of L-X-ray of Xe emitted by Xe26+ is estimated.</span
Transverse coupling property of beam from ECR ion sources
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);">Experimental evidence of the property of transverse coupling of beam from Electron Cyclotron Resonance (ECR) ion source is presented. It is especially of interest for an ECR ion source, where the cross section of extracted beam is not round along transport path due to the magnetic confinement configuration. When the ions are extracted and accelerated through the descending axial magnetic field at the extraction region, the horizontal and vertical phase space strongly coupled. In this study, the coupling configuration between the transverse phase spaces of the beam from ECR ion source is achieved by beam back-tracking simulation based on the measurements. The reasonability of this coupling configuration has been proven by a series of subsequent simulations. (C) 2014 AIP Publishing LLC.</span
Quasi-elastic scattering of C-10,C-11 and B-10 from a Pb-nat target
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);">Angular distributions of the differential cross sections for the quasi-elastic scattering from a Pb-nat target by C-10 at 226 and 256 MeV, by C-11 at 222 MeV and 226 MeV, and by B-10 at 173 MeV were measured at the Heavy Ion Research Facility in Lanzhou, Radioactive Ion Beam Line in Lanzhou (HIRFL-RIBLL). Contributions from the inelastic scattering channels to these data are found to be negligibly small with coupled-channel calculations within the angular range covered by this experiment. These data can be well reproduced by optical model calculations with systematic nucleus-nucleus potentials. The reduced total reaction cross sections were compared with other existing data</span
Transmission of 200 keV H+2 Ions through Tapered Capillaries in PC
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);">Transmission of H-2(+) ions through tapered capillaries in insulating polycarbonate (PC) foil is reported. Guiding, focusing effects and multi-peaks phenomena on ions through capillaries have been studied.</span
Stripping accumulation and optimization of HIMM synchrotron
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 design of an injection system for a dedicated carbon-ion therapy synchrotron is presented. Improvements to the particle tracking code ACCSIM are developed to support interactions between heavy ions and stripping foil. The three main improvements are concerned with (a) charge exchange between carbon ions and stripping foil; (b) multiple Coulomb scattering of incident heavy ions on stripping foil; and (c) energy loss in particles passing through the foil, and energy-loss straggling. The accumulation process is then simulated, and the parameters related to the injection system are optimized. A gain of about 140 in the number of particles is achieved, and the emittance and momentum spread growth is obtained, together with a central momentum shift. Finally, the superacceptance of the synchrotron, epsilon - Delta p/p, is tracked. According to the simulation, 1.35 x 10(9) actual particles are stored successfully in the synchrotron. (C) 2014 Elsevier B.V. All rights reserved</span