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利用中国科学院近代物理研究所的电子回旋共振离子源引出的高电荷态氮离子(Nq+,q=3,5,6),在4.5~120 keV动能范围内系统测量了Nq+(q=3,5,6)与Cu表面碰撞产生的K-X射线能谱;基于原子壳层电离理论计算了K-X射线产额值及其电离截面值。结果表明:Nq+(q=3,5)离子进入靶表面后与Cu原子发生紧密碰撞,在直接库伦电离的作用下发射K-X射线,并且随着入射离子动能的增加,K-X射线产额和K壳层电离截面均单调增大;对于N6+离子,K-X射线产额与其入射动能没有明显的依赖关系,且在Cu表面形成的"空心原子"级联退激产生的K-X射线产额约占其总K-X射线产额的97%。另外,N5+离子入射时的K-X射线产额明显高于N3+离子入射时的产额。本工作对离子与表面相互作用中形成的"空心原子"的退激过程具有重要的参考价值,并为理解"空心原子"的退激过程和彗星X射线机理的研究提供了基础数据。 相似文献
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~(238)U裂变产额测量工作在核数据测量中有着重要意义,本工作利用2.5MeV质子静电加速器产生的1.4MeV-5MeV单能中子诱发238U裂变,通过对裂变产物放射性的测量对裂变产物核素~(135)I、~(133)I、~(105)Ru和~(91)Sr的产额进行了测定。照射过程中中子通量用活化法确定。分析了影响实验测量的多个因素,包括用MCNPX程序对中子在靶头及样品中的多次散射和自屏蔽效应进行了修正,对γ射线在样品中的自吸收进行修正等。得到产额数据典型误差为3.5%,最后把测量结果与已有的裂变产额数据进行比对。 相似文献
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235U的裂变产物产额是核能应用和核物理研究中的重要基础数据。本工作应用高纯锗γ能谱法绝对测量了0.57、1.0 MeV和1.5 MeV中子诱发235U裂变的各能量点30个质量链的产额数据。样品的裂变率通过双裂变室监测,并利用蒙特卡罗(MCNP)模拟了辐照时样品的中子能谱,结果与国际上相应能量点数据在实验不确定度范围内吻合。本工作得到的产额数据澄清了原有数据最高16%的差异并将数据精度从国际上原有数据精度5%~7%提高到3%~5%。 相似文献
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《核动力工程》2010,(Z2)
简述热中子转换为14MeV中子的原理。建立了由一个热中子转换为可利用的14MeV中子的有效产额的计算分析模型。计算出热中子被6Li吸收的概率、氚核T在6LiD中未泄漏的概率;给出了氚核T和氘核D发生聚变反应以及氚核T与6Li发生聚变反应的截面及其14MeV中子的产额随6LiD厚度变化的曲线。结果表明:当6LiD材料的厚度在0~0.5 mm范围内时,14MeV中子的有效产额随6LiD厚度近似直线增大,然后随6LiD厚度缓慢增加逐渐趋于一个稳定值;当6LiD材料的厚度分别为0.7、1.0 mm时,一个热中子转换为14MeV中子的可利用的有效产额分别为3.18×10-4和3.53×10-4。 相似文献
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采用与单光电子相比较的方法测量了国产GSO晶体样品的光电子产额,结果表明,GSO样品的光电子产额及能量分辨率与闪烁体在光电倍增管光阴极面上的放置方式有关,在较好条件下,被测GSO晶体的光电子产额可到2013phe/MeV,对137Cs 661.6keV光峰的能量分辩为FWHM=10.1%. 相似文献
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为了测量惯性约束聚变实验中聚变反应的时间过程,提出了一种高时间分辨的聚变反应历程测量系统设计。该系统主要由闪烁体及鼻锥、光学成像系统和条纹相机系统三部分组成。用于能量分别为2.45MeV和14.03MeV的聚变中子测量时,系统的时间分辨分别优于55ps和40ps,对应的测量下限中子产额分别为1.5×109和4×108。 相似文献
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用阈探测器中子活化法测量了50MeV/u ~(12)C离子实验靶区的次级中子平均注量率、角分布、粗略能谱,并估算了重离子反应的中子产额。 相似文献
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An experimental apparatus for studies of MeV ion beam modification of materials has been established on a 3 MV tandem accelerator at Fudan university. A system of X-Y electrostatic scanning implantation of MeV heavy ions and in situ Rutherford. backscattering analysis was included in it. The uniformity of scanning implantation was checked by the RBS measurement of a Si wafer implanted with 1 MeV Au ions. MeV ion beam mixing of Au/Si, Au/Ge and Ag/Si systems was preliminarily studied. The samples were irradiated by certain fluences of 1 MeV Ag ions at room temperature. The mixed layers were analyzed in situ using the glancing RBS technique with 2 MeV 4He+ ions. For Au/Si system, a uniformly mixed layer with a defined composition is obtained, and the intermixing is much less for Ag/Si system than for Au/Si system. 相似文献
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用活化法以^27Al(n,α)^24Na反应截面为中子通量标准,对14McV能区中子引起的^58Ni(n,p)^58m gCo反应截面进行了测量。中子能量是用金硅面垒半导体探测器测定的。 相似文献
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M.J. Bailey B.N. Jones S. Hinder J. Watts S. Bleay R.P. Webb 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(11-12):1929-1932
Police institutions currently have no analytical method of knowing whether a fingerprint was deposited before or after the document was written or printed. The suitability of using MeV secondary ion mass spectrometry (i.e. SIMS with an MeV ion beam) to determine the order in which a fingerprint and written text were deposited on paper was therefore investigated. A 10 MeV O4+ beam was used to generate secondary ions from the surface of the samples and to map the molecular fragments from doped fingerprints and inks on paper. The images obtained and the sputtering behaviour of the samples was found to be indicative of the sequence of ink and fingerprint deposits. 相似文献
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《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1999,147(1-4):142-147
Carbon nanotubes (CNT) were produced by high energy, heavy ion irradiation (215 MeV Ne, 246 MeV Kr, 156 MeV Xe) of graphite. On samples irradiated with Kr and Xe ions large craters were found by atomic force microscopy, these are attributed to sputtering. Frequently one or several CNTs emerge from the craters. Some of the observed CNTs showed a regular vibration pattern. No other carbon based materials, like amorphous carbon or fullerenes were evidenced. Focused ion beam cuts were used to compare CNTs with surface folds on graphite. 相似文献
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Tian-bing Xu Pei-ran Zhu Jun-si ZhouDaiqing Li Baoan Gong Ya WanShanming MuQing-tai Zhao Zhong-lie Wang 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1994,90(1-4):392-395
The lattice damage accumulation in GaAs and Al0.3Ga0.7As/GaAs superlattices by 1 MeV Si+irradiation at room temperature and 350°C has been studied. For irradiations at 350°C, at lower doses the samples were almost defect-free after irradiation, while a large density of accumulated defects was induced at a higher dose. The critical dose above which the damage accumulation is more efficient is estimated to be 2 × 1015 + Si/cm2 for GaAs, and is 5 × 1015 Si/cm2 for Al0.8Ga0.7As/GaAs superlattice for implantation with 1.0 MeV Si ions at 350°C. The damage accumulation rate for 1 MeV Si ion implantation in Al0.3Ga0.7As/GaAs superlattice is less than that in GaAs. 相似文献
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Y. Mokuno Y. Horino A. Chayahara A. Kinomura N. Tsubouchi K. Fujii M. Terasawa T. Sekioka T. Mitamura 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1997,130(1-4):243-246
An X-ray crystal spectrometer using a position sensitive proportional counter combined with tandem microbeam line at Osaka National Research Institute have been developed. This system realizes high energy resolution PIXE analysis using a heavy ion microbeam (E < 6 MeV) with reasonable detection efficiency. The design of the spectrometer, such as detection geometry, detectable energy range and energy resolution, are described. This system was applied to high energy resolution PIXE analysis of Ti, SUS and Si with 2 MeV proton and 5 MeV Si3+ focused or collimated beams. The best energy resolution was 2 eV for the Si K line. 相似文献
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Bibhudutta Rout Richard R. Greco Daniel P. Zachry Alexander D. Dymnikov Gary A. Glass 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2006,250(1-2):76-80
Energetic (MeV) Au implantation in Si(1 0 0) (n-type) through masked micropatterns has been used to create layers resistant to KOH wet etching. Microscale patterns were produced in PMMA and SU(8) resist coatings on the silicon substrates using P-beam writing and developed. The silicon substrates were subsequently exposed using 1.5 MeV Au3+ ions with fluences as high as 1 × 1016 ions/cm2 and additional patterns were exposed using copper scanning electron microscope calibration grids as masks on the silicon substrates. When wet etched with KOH microstructures were created in the silicon due to the resistance to KOH etching cause by the Au implantation. The process of combining the fabrication of masked patterns with P-beam writing with broad beam Au implantation through the masks can be a promising, cost-effective process for nanostructure engineering with Si. 相似文献
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Y.S. Katharria Sandeep Kumar D. Kanjilal 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,260(2):563-566
Silicon carbide (SiC) precipitates buried in Si(1 0 0) substrates were synthesized by ion implantation of 50 keV and 150 keV C+ ions at different fluences. Two sets of samples were subsequently annealed at 850 °C and 1000 °C for 30 min. Fourier transform infrared (FTIR) spectroscopy studies and X-ray diffraction (XRD) analysis confirmed formation of β-SiC precipitates in the samples. Ion irradiation with 100 MeV Ag7+ ions at room temperature does not induce significant change in the precipitates. It could be interpreted from the FTIR observations that ion irradiation may induce nucleation in Si + C solution created by ion implantation of C in Si. Modifications induced by swift heavy ion irradiation are found to be dependent on implantation energy of C+ ions. 相似文献
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Stopping power measurements of heavy ions (3 ? Z1 ? 14) in Mylar foil by time-of-flight spectrometry
H. Ammi C.A. Pineda-Vargas S. MammeriM. Msimanga S. OurabahA. Dib 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(3):386-391
Heavy ions elastic recoil detection analysis coupled with time of flight spectrometer (HIERDA_ToF-E) have been used to measure energy loss of charged particles in thin absorber. The stopping power of heavy ions has been determined in Mylar for 28Si, 27Al, 24Mg, 19F, 16O, 12C and 7Li ions over a continuous range of energies 0.14-0.80 MeV/nucleon. The ions were recoils from the bombardment of different samples (Si, MgO, Al2O3, LiF and C) with a 27.5 MeV Kr+ beam. The energy loss of the recoil atoms is measured with and without additional foils placed in front of a Surface Barrier Detector (SBD). The energy of individual ions is determined from its ToF data; the exit energy after the stopping foil is measured using the SBD detector. We have compared our stopping values to those predicted by SRIM-2008 computer code, ICRU-73 stopping data tables, MSTAR calculations and to the published data from literature. The results show good agreement with limited existing data but indicate a large deviation among the predicted theoretical values at the low energy side of the stopping maximum peak. 相似文献
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利用95MeV/u的16O束产生的次级束流对半导体硅探测器进行了时间和能量定标。实验结果表明,由于次级束流提供的次级粒子种类多,飞行距离长,因此,能给探测器带来非常精确的定标。 相似文献