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Experimental Study of Two-Alpha Emission from High-Lying Excited States of ~(17,18)Ne
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 experiments of two-alpha emission from Ne-17,Ne-18 excited levels were performed at the HIRFL-RIBLL facility of the Institute of Modern Physics, Lanzhou. The beams of Ne-17 at the energy of 49.9 MeV/u and Ne-18 at 51.8 MeV/u bombarded a Au-197 target to populate excited states of Ne-17,Ne-18 via Coulomb excitation. Complete kinematics measurements were achieved by the detectors of a silicon strip and CsI+PIN array. The experimental results combined with simple MC simulations show the characteristic of sequential two-alpha emission via O-14 excited states for Ne-18. The results of two-alpha emission from Ne-17 are preliminary and need further analyses.</span
Design of Coupled Stripline Directional Coupler Power Synthesizer
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);">介绍了直线加速器高频全固态功率源中大功率合成器件-3 dB定向耦合器的理论计算和工程设计过程,该合成器工作频率80.5 MHz,输出连续波功率大于20 kW。分析了合成器的功率容量,并对相应的理论计算结果、CST(Computer Simulation Technology)软件模拟计算结果和实际功率合成器件测量结果进行了比较。通过比较得出,CST仿真结果与测试结果基本一致,隔离度和电压驻波比等实测指标优于设计指标,只有耦合度与设计指标有些偏差,总体上达到了预期的设计要求。在输出功率20 kW时,取样波形无失真,合成器无明显温升,满足固态功率源大功率稳定运行的要求。</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);">The principle of design and calculation of the power synthesis in the solid-state amplifier are described in this paper.The working frequency of the synthesizer is 80.5 MHz.The output continuous wave power is more than 20 kW;The synthesizer power capacity is analyzed.The theoretical calculation results,Computer Simulation Technology(CST) simulated results are compared with the measured results of the actual 3 dB couplers.The analysis of the measured results and CST calculated results shows that the simulation is in agreement with the measurement results which meet the design requirements of the solid-state amplifier.Except the coupling coefficient,the isolation,the VSWR and other parameters are better than the design target.When the output power is 20 kW,the sampling waveform has no deform and the temperature of the synthesizer is stable.</span
The effects of Xe irradiation on He and H co-implanted Si
No full textA combination of X-ray diffraction, cross-sectional transmission electron microscopy (XTEM), and Raman spectroscopy was used to study the effects of irradiation with swift heavy ions on helium and hydrogen co-implanted silicon. < 100 >-oriented silicon wafers were co-implanted with 30 keV helium to a dose of 3 x 10(16) He+/cm(2) and 24 keV protons to a dose of 2 x 10(16) H+/cm(2). Moreover, selected helium and hydrogen co-implanted Si wafers were irradiated with 94 MeV xenon. After He and H co-implantation and Xe-irradiation, the wafers were annealed at a temperature of 673K for 30 min. The damage region of the wafers was examined by the XTEM analysis. The results reveal that most of the platelets are aligned parallel to the (100) plane in the He and H co-implanted Si. However, majority of the platelets lie in {111} planes after Xe irradiation. Blisters do not occur on the sample surface after Xe irradiation. Raman results reveal that the intensities of both SiH2 and V2H6 modes increase with the increase in the dose of Xe. A possible explanation is that strong electronic excitation during Xe irradiation produces annealing effect, which reduces both lattice damage and the out-of-plane tensile strain
Progress on the Lanzhou Penning Trap
No full textThe Penning trap is one of the most important experimental devices in the field of nuclear physics, and measures atomic masses with the highest precision in the world. Many such devices are currently in operation, with more being designed and constructed. To start the experimental study of atomic masses with very high precision in China, the Lanzhou Penning Trap (LPT) is being constructed at the Institute of Modern Physics, Chinese Academy of Sciences. In this paper the progress and status of the LPT will be reported.National Natural Science Foundation of China;Chinese Academy of Sciences;Ministry of Science and Technology of Chin
医用偏转磁聚焦结构的重离子或质子同步加速器
No full text本发明涉及医用带电粒子同步加速器磁聚焦结构的设计方法技术领域，尤其是涉及一种医用45°偏转磁聚焦结构的重离子或质子同步加速器。包括有八个偏转二极铁和八个同步加速器直线段，所述的八个偏转二极铁和八个同步加速器直线段依次通过环形真空管道交替连接，所述的八个偏转二极铁均为45°偏转二极铁。采用45°偏转磁聚焦结构包括一个带电粒子运行在其中的环形真空管道，以及布置在环形管道上的磁铁元件、加速元件、注入引出元件。有效的利用同步加速器空间，安装尽可能少的元件实现医用重离子/质子医用同步加速器功能，最大程度的降低制造成本和安装空间，提高治疗效率，降低治疗成本
Active spot-scanning test with heavy ions at HIRFL-CSR
No full textAn active spot beam delivery system for heavy ion therapy has been developed based on the Cooling Storage Ring at HIRFL-CSR, where the pencil carbon-ion beams were scanned within a target volume transversely by a pair of orthogonal (horizontal and vertical) dipole magnets to paint the slices of the target volume and longitudinally by active energy variation of the synchrotron slice by slice. The unique techniques such as dose shaping via active energy variation and magnetic deflection constitute a promising three-dimensional conformal even intensity-modulated radiotherapy with heavy ions at HIRFL-CSR. In this paper, the verification of active energy variation and the calibration of steerable beam deflection are shown, as the basic functionality components of the active spot-scanning system. Additionally, based on the capability of creating homogeneous irradiation fields with steerable pencil beams, a radiobiological experiment like cell survival measurement has been performed aiming at comparison of the radiobiological effects under active and passive beam deliveries
Experimental Study of Two-Alpha Emission from High-Lying Excited States of Ne-17,Ne-18
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 experiments of two-alpha emission from Ne-17,Ne-18 excited levels were performed at the HIRFL-RIBLL facility of the Institute of Modern Physics, Lanzhou. The beams of Ne-17 at the energy of 49.9 MeV/u and Ne-18 at 51.8 MeV/u bombarded a Au-197 target to populate excited states of Ne-17,Ne-18 via Coulomb excitation. Complete kinematics measurements were achieved by the detectors of a silicon strip and CsI+PIN array. The experimental results combined with simple MC simulations show the characteristic of sequential two-alpha emission via O-14 excited states for Ne-18. The results of two-alpha emission from Ne-17 are preliminary and need further analyses.</span
Mass Measurements of the Neutron-Deficient Ti-41, Cr-45, Fe-49, and Ni-53 Nuclides: First Test of the Isobaric Multiplet Mass Equation in f p-Shell Nuclei
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);">Isochronous mass spectrometry has been applied to neutron-deficient Ni-58 projectile fragments at the HIRFL-CSR facility in Lanzhou, China. Masses of a series of short-lived T-z = -3/2 nuclides including Ti-41, Cr-45, Fe-49, and Ni-53 have been measured with a precision of 20-40 keV. The new data enable us to test for the first time the isobaric multiplet mass equation (IMME) in f p-shell nuclei. We observe that the IMME is inconsistent with the generally accepted quadratic form for the A = 53, T = 3/2 quartet. We perform full space shell model calculations and compare them with the new experimental results.</span