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Arup Bandyopadhyay 《Pramana》2002,59(6):933-939
Variable Energy Cyclotron Centre (VECC) is presently developing an ISOL post-acclerator type of RIB facility. The scheme utilises
the existing K=130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency
quadrupole (RFQ) and LINAC modules for the post-acceleration. The design aspects of these post-accelerator LINAC modules will
be discussed in this paper. 相似文献
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介绍了北京大学分离作用射频四极场(RFQ)加速器的结构特点,包括膜片式电极、支撑环式电极支撑系统、水冷系统、调谐系统及其工艺实现;介绍了基于该分离作用RFQ加速腔进行的调谐测试、高功率实验和束流实验。结果表明:调谐系统的频率调节范围及品质因数完全满足实验要求;分离作用RFQ加速腔的输入功率可以达到33 kW以上,满足高功率下稳定运行的条件;在束流实验中,把1.03 MeV的O+入射束流加速到1.65 MeV,半高宽能散小于3%。加速器结构满足物理设计要求,加速系统运行稳定。 相似文献
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介绍了北京大学分离作用射频四极场(RFQ)加速器的结构特点,包括膜片式电极、支撑环式电极支撑系统、水冷系统、调谐系统及其工艺实现;介绍了基于该分离作用RFQ加速腔进行的调谐测试、高功率实验和束流实验。结果表明:调谐系统的频率调节范围及品质因数完全满足实验要求;分离作用RFQ加速腔的输入功率可以达到33 kW以上,满足高功率下稳定运行的条件;在束流实验中,把1.03 MeV的O+入射束流加速到1.65 MeV,半高宽能散小于3%。加速器结构满足物理设计要求,加速系统运行稳定。 相似文献
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P N Ostroumov 《Pramana》2002,59(6):895-913
The Nuclear Science Community in the Unites States has unanimously concluded that developments in both nuclear science and
its supporting technologies make building a world-leading Rare-Isotope Accelerator (RIA) facility for production of radioactive
beams the top priority. The RIA development effort involves several US Laboratories (ANL, JLAB, LBNL, MSU, ORNL). The RIA
facility includes a CW 1.4 GeV driver LINAC and a 100 MV post-accelerator both based on superconducting (SC) cavities operating
at frequencies from 48 MHz to 805 MHz. An initial acceleration in both LINACs is provided by room temperature RFQs. The driver
LINAC is designed for acceleration of any ion species; from protons up to 900 MeV to uranium up to 400 MeV/u. The novel feature
of the driver LINAC is an acceleration of multiple charge-state heavy-ion beams in order to achieve 400 kW beam power. Basic
design concepts of the driver LINAC are given. Several new conceptual solutions in beam dynamics, room temperature and SC
accelerating structures for heavy ion accelerator applications are discussed. 相似文献
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设计了750 keV,201.25 MHz的RFQ注入器的射频结构,对四杆型RFQ结构进行了简要的理论分析,在束流动力学设计的基础上,对射频结构进行了优化。研究了四杆型RFQ结构中支撑板高度、宽度、厚度、间距、形状、外腔体半径等因素对射频特性的影响,进行了优化设计并给出了主要的结构参数及射频特性的设计结果。优化设计得到的四杆型RFQ腔体长度126 cm,在极间电压80 kV时,峰值功率损耗为115.95 kW,二极场因子为1.004,电场沿轴向分布比较均匀,偏差小于3.5%,满足了物理需求。 相似文献
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从系统设计的角度出发,提出了利用数字频率合成技术和功率增益自动控制技术稳定等离子体激励源的频率和功率,从而降低天线噪声、提高等离子体天线性能。实验结果证明了此方法可行性。 相似文献
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WANG Zhi CHEN Jia-Er LU Yuan-Rong GUO Zhi-Yu YAN Xue-Qing ZHU Kun KANG Ming-Lei FANG Jia-Xun 《中国物理C(英文版)》2010,34(4):502-505
SFRFQ (Separated Function Radio Frequency Quadrupoles) accelerator is a new post accelerator of RFQ (Radio Frequency Quadrupoles) type, which has been developed since the beginning of the 1990s at Peking University. In order to demonstrate the possibility of the SFRFQ, a prototype cavity has been designed.A special dynamics design method has been proposed to avoid the sparking problem and decrease the energy spread at the exit of SFRFQ. It consists of two aspects: the asymmetry structure design for transverse focusing and the inner buncher design for longitudinal bunching. This allows the improvement of the beam properties without increasing the cavity length. The simulation results show that the energy spread can be substantially reduced by using the inner buncher in the SFRFQ structure. 相似文献
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SFRFQ (Separated Function Radio Frequency Quadrupoles) accelerator is a new post accelerator of RFQ (Radio Frequency Quadrupoles) type, which has been developed since the beginning of the 1990s at Peking University. In order to demonstrate the possibility of the SFRFQ, a prototype cavity has been designed. A special dynamics design method has been proposed to avoid the sparking problem and decrease the energy spread at the exit of SFRFQ. It consists of two aspects: the asymmetry structure design for transverse focusing and the inner buncher design for longitudinal bunching. This allows the improvement of the beam properties without increasing the cavity length. The simulation results show that the energy spread can be substantially reduced by using the inner buncher in the SFRFQ structure. 相似文献
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Boron carbon nitride films were deposited by radio frequency magnetron sputtering using a composite target consisting of h-BN and graphite in an Ar-N2 gas mixture. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results suggest that the films are atomic-level hybrids composed of B, C and N atoms. The boron carbon nitride films prepared in the present experiment have a disordered structure. The sputtering power varied from 80 W to 130 W. This sputtering power was shown to have regular effect on the composition of boron carbon nitride films. The samples deposited at 80 W and 130 W are close to the stoichiometry of BC3N. The sample deposited at 110 W is close to the stoichiometry of BCN. The samples deposited at 100 W and 120 W approach to BC2N. It is very significant for us to synthesize boron carbon nitride compound with controllable composition by changing the sputtering power. 相似文献
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采用PIC-MC自洽模型,模拟了氮气电容性耦合射频放电的微观等离子体过程及带电粒子(e,N2+,N+)的行为。结果表明,离子(N2+,N+)的运动状态滞后瞬时射频电场的变化;在两极附近,N2+具较高密度,但能量较低,N+具较低的密度但能量较高,两者的密度差6倍左右。两种离子轰击射频电极的能量分布变化规律类似,随放电参数变化,离子(N2+,N+)能量变化显著,其密度变化不明显。模拟的电子能量几率分布与测量结果一致。 相似文献
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Radio frequency fingerprint (RFF) has attracted a remarkable surge of attention to wireless transmitter identification due to the inimitable hardware imperfection. However, most RFF-based schemes devised in controlled environments are unable to reach the claimed performance in real-world scenarios. This paper proposes a practical RFF identification method for mobile phones in Global System for Mobile (GSM) system. Specifically, the instantaneous amplitude of near-transient part in normal burst (NB) is regarded as RFF that extracted from up-link communications. In addition, an anomaly filtering and stacking (AFS) method is introduced to obtain stable RFF in Time Division Multiple Access (TDMA) system. Lastly, the impacts of frequency point and sending power variations on RFF are fully dissected in comparison experiments. Experiments on 10 mobile phones show that the proposed RFF scheme yields 99.17% True Acceptance Rate (TAR) in real wireless environments. Experiments also show that the varying transmission power decreases the accuracy of RFF identification. 相似文献
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ZnO films doped with different contents of indium were prepared by radio frequency sputtering technique. The structural, optical and emission properties of the films were characterized at room temperature using XRD, XPS, UV-vis-NIR and PL techniques. Results showed that the indium was successfully incorporated into the c-axis preferred orientated ZnO films, and the In-doped ZnO films are of over 80% optical transparency in the visible range. Furthermore, a double peak of blue-violet emission with a constant energy interval (∼0.17 eV) was observed in the PL spectra of the samples with area ratio of indium chips to the Zn target larger than 2.0%. The blue peak comes from the electron transition from the Zni level to the top of the valence band and the violet peak from the InZn donor level to the VZn level, respectively. 相似文献
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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. 相似文献
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A superconducting linear accelerator (LINAC) to boost the energy of the heavy ion beams from the 14 UD pelletron accelerator
at Mumbai is under development. The booster is based on quarter wave resonators (QWR) coated with lead which is superconducting
at liquid helium temperature. The operating frequency is 150 MHz. Four resonators each are mounted in a cryostat module built
indigenously. A total of seven such modules arranged in two arms with an isochronous and achromatic beam bend in the middle
comprises the full LINAC. The transverse focusing of the beam through the LINAC is carried out using periodic quadrupole doublet
magnets operating at room temperature. The present status of the project is described. 相似文献