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描述了在兰州放射性束流线(RIBLL)上用78.6MeV/u的14N束流轰击Be靶产生出34.9MeV/u的12N次级束流. 利用12N轰击Si靶作为次级靶, 利用直接碎裂反应测量它的反应总截面. 利用理论模型进行了计算, 理论计算和实验结果符合的很好. 发现12N的质子密度分布相对于中子而言, 有一个很大的弥散. 相似文献
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135MeV/u 12C和铁相互作用中靶余核的质量分布 总被引:1,自引:1,他引:0
用核化学技术测定了135MeV/u 12C和铁相互作用中的靶余核的生成截面,通过高斯电荷分布函数得到了靶余核的质量分布.与46MeV/u 12C+Cu相比,发现A<30质量区的产额明显增加,且产物有偏向丰中子一侧的趋势.实验测定的质量分布与熔合碎裂模型和级联两体模型的计算结果进行了比较,结果似乎表明在很高入射能情况下多重碎裂衰变是A<30靶余核生成的主要反应机制. 相似文献
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采用了通用高速A/D采集器采集信号数据,用软件的方法开发出了具备多道能谱脉冲识别和计数分析能力的软件.用此软件实现了每次托卡马克放电后,在较短的时间内从庞大的原始采集数据中提取出能谱脉冲数据,计算和显示能谱图,这为下一步测量电子温度打下了基础,并同时实现了数据共享. 相似文献
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Zhu LY Arrington J Averett T Beise E Calarco J Chang T Chen JP Chudakov E Coman M Clasie B Crawford C Dieterich S Dohrmann F Dutta D Fissum K Frullani S Gao H Gilman R Glashausser C Gomez J Hafidi K Hansen JO Higinbotham DW Holt RJ De Jager CW Jiang X Kinney E Kramer K Kumbartzki G LeRose J Liyanage N Mack D Markowitz P McCormick K Meekins D Meziani ZE Michaels R Mitchell J Nanda S Potterveld D Ransome R Reimer PE Reitz B Saha A Schulte EC Seely J Sirca S Strauch S Sulkosky V Vlahovic B 《Physical review letters》2003,91(2):022003
We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams. 相似文献
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Based on the neutron induced fission fragment mass distribution data up to neutron energy 20 MeV measured with the double kinetic energy method (KEM) and the radio active method (RAM), the systematics of fission fragment mass distribution was investigated by using 5 Gaussian model and the systematics parameters were obtained by fitting the experimental data. With the systematics, the yields of any mass A and at any energy in the region from 0 to 20 MeV of neutron energy can be calculated. The calculated results could well reproduce the experimental data measured with KEM, but show some systematical deviation from the data measured by RAM, which reflects some systematical deviations between the two kinds of measured data.The error of systematics yield was calculated in an exact error transformation way, including from the error of the experimental yield data to the error of the discrete parameters, then to the systematics parameters,and at last to the yield calculated with systematics. 相似文献
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Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy are described by a simple formula. The calculated results are in agreement with the experimental data of carbon and oxygen induced interactions at Dubna energy. The comparison between the calculated results and experimental data shows that particles are emitted isotropically in the rest frame of the emission sources, and the emission sources have movements in momentum space. 相似文献
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Electron Loss Spectroscopy (ELS), X-ray Photoemission (XPS), Secondary Emission Energy Distribution, and Secondary Electron yield data have been obtained on both evaporated films and sprayed-on coatings of BaO. Using the ELS correlated with the XPS data, bulk and surface plasmon losses as well as excitonic and interband transition electron loss mechanisms have been identified. It was found that at low primary beam energies (<100 eV), structure in the secondary emission energy distribution could be correlated with a conduction band energy structure. This structure was consistent with the model used to explain the loss transitions. The structure in the energy distribution curves shows little, if any, correlation with plasmon decay mechanisms and other two-step electron emission processes. On the contrary, for the case of BaO (at least at low primary energies), the energy distribution data and structure in the secondary yield vs. primary beam energy data indicate that most secondaries are produced by direct excitation of secondaries by the primary electrons. 相似文献
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SHAO Gui-Cheng 《中国物理C(英文版)》2010,34(3)
Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy are described by a simple formula.The calculated results are in agreement with the experimental data of carbon and oxygen induced interactions at Dubna energy.The comparison between the calculated results and experimental data shows that particles are emitted isotropically in the rest frame of the emission sources,and the emission sources have movements in momentum space. 相似文献
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The critical dose at which an implanted amorphous layer in silicon is formed cannot be explained by a previous energy independent model. An energy dependent correction to this model can explain our ESR data as well as other data. The correction is most important for light ions. 相似文献
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PSⅡ颗粒二聚体中类胡萝卜素向反应中心传能研究 总被引:3,自引:3,他引:0
运用瞬态荧光光谱技术在77 K低温下对PSⅡ颗粒复合物中类胡萝卜素(Car)分子的能量传递过程进行研究, 通过不同激发波长473 nm, 481 nm, 507 nm选择性激发PSⅡ颗粒复合物中色素分子, 得到PSⅡ颗粒二聚体中关于Car能量传递的三组时间组分:16.6 ps, 130~183 ps, 217~249 ps. 其中16.6 ps反映了LHCⅡ中的Car分子将能量通过中间体Cars、Chls分子传递到Chl639的过程; 130~183 ps为核心天线中的β-Car分子向RC的能量传递时间; 217~249 ps为LHCⅡ中Car481通过中间Chla分子向RC的传能时间. 相似文献