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2011年  第28卷  第2期

核物理
张量力对原子核性质的影响(英文)
曹李刚
2011, 28(2): 135-141. doi: 10.11804/NuclPhysRev.28.02.135
摘要:
最近一段时期, 对张量力性质研究成为原子核结构研究的热点之一。 基于自洽的Skyrme平均场理论讨论了张量力研究的最新进展。 同时, 讨论了张量力和Skyrme能量密度中的中心交换项对原子核单粒子态的演化以及多极巨共振的贡献。 发现考虑张量力贡献后,利用Skyrme平均场计算可以基本描述Z=50和N=82原子核单粒子态演化的实验结果。而张量力对于原子核电多极巨共振基本没有影响,只对其低能集体态有一定的影响。 张量力的引入使得原子核磁单极巨共振的能量和强度发生显著的改变。 通过对数值结果的分析,发现张量力会产生吸引的粒子-空穴剩余相互作用。The impact of the tensor force on the properties of finite nuclei is discussed by analyzing the spinorbit splittings and the multipole giant resonances in nuclei. It is found that the tensor force do plays an important role in nuclear structure. The experimental isospin dependence of the spinorbit splitting is very well depicted when the tensor force is included. The tensor force has a larger effect on the spin flip magnetic dipole states than on the natural parity isoscalar quadrupole(2+) states. By analyzing the modifications to the HartreeFock mean field induced by the tensor terms,and the specific features of the residual particlehole tensor interaction,we find that the tensor force gives an attractive contribution to the particlehole matrix elements.
大入射能量范围内重离子输运过程的动力学性质研究
李庆峰, 李祝霞, M. Bleicher, H. Stoecker
2011, 28(2): 142-156. doi: 10.11804/NuclPhysRev.28.02.142
摘要:
基于一个改进的微观动力学输运模型——极端相对论量子分子动力学(UrQMD), 较为系统地研究了从SIS能区到AGS和SPS能区, 再到RHIC能区, 入射能量跨5个数量级的重离子核反应及多个人们感兴趣的实验观测量, 如粒子产额、 集体流、 核阻止以及两粒子HBT关联等。研究表明, 不论单粒子观测量, 还是两粒子关联观测量, 都能自洽地由同一个输运模型加以描述。Based on one updated microscopic transport model Ultrarelativistic Quantum Molecular Dynamics (UrQMD) with modifications of both potentials and twobody scattering cross sections, quite a few interesting observables, such as yields, collective flows, the nuclear stopping, and the HBT twoparticle interferometry, are systematically investigated for heavy ion collisions within a large beam energy regime of five orders of magnitude (from SIS, AGS, SPS up to RHIC). It is shown that a consistent explanation can be received from both singleparticle and twoparticle related observables.
同位旋效应对F同位素s-d能级间隙的影响
郭艳青, 任中洲
2011, 28(2): 157-161. doi: 10.11804/NuclPhysRev.28.02.157
摘要:
在单粒子势模型的框架下, 计算了O同位素和F同位素的基态和某些低激发态的能级值、均方根半径值及密度分布。通过在伍兹萨克逊势中引入同位旋依赖项, 研究了同位旋效应对F同位素s-d能级间隙的影响。理论计算得到的均方根半径值和自旋宇称值与实验结果一致。尤其是, 理论计算能够实现16F, 15F和14F中2s1/2与1d5/2质子能级间的反转, 且F同位素中s-d质子能级间隙及其整体变化趋势与已知实验结果符合较好。此外, 理论结果表明17F的(1/2)+第一激发态为单质子晕态。 The level structures of O and F isotopes are investigated in the framework of the singleparticle potential model. The isospin effect on the sd level spacing in F isotopes is studied by introducing an isospindependent term in the depth of the WoodsSaxon potential. The theoretical results of RMS radii and spinparity values are in agreement with the experimental data. In particular, the level inversion between proton levels of 2s1/2 and 1d5/2 in 16F, 15F and 14F is reproduced. The global tendency of the s-d level spacing agrees with the observed fact. In addition, the study confirms the oneproton halo structure in 17F(2s1/2).
基于Pluto事件产生器对兰州强子物理谱仪上主要反应道的模拟研究
郑川, 徐瑚珊, 欧阳珍, 袁小华, 王建松
2011, 28(2): 162-167. doi: 10.11804/NuclPhysRev.28.02.162
摘要:
为了在 GeV 能区开展核子核子相互作用中强子的产生和衰变的实验研究, 将在 HIRFLCSR 主环上建造一台兰州强子物理谱仪(HPLUS)。 首先结合 HPLUS 的初步构型阐明了针对不同极角区域的粒子鉴别方法, 接着介绍了在蒙特卡罗模拟中使用的 Pluto 事件产生器, 并针对 HPLUS上主要的反应道模拟研究了: Pluto 产生的质子质子弹性散射的角分布和实验数据的符合程度; 在产生 K 介子的反应道中, HPLUS 前角区对 K 介子的接收度; 强子衰变产生光子的最大能量和两个光子的最小夹角随极角区域的变化情况; 不同的重建方法对核子激发态质量谱形状的影响。以上研究说明了 Pluto 事件产生器可以满足 HPLUS 模拟的需要。 Hadron Physics Lanzhou Spectrometer (HPLUS) is designed for the study of hadron production and decay from nucleonnucleon interaction in the GeV region. The current formation of HPLUS and the particle identification methods
for three polar angle regions are discussed. The Pluto event generator is applied to simulate the primary reactions on HPLUS, concerning four issues as followed: the agreement on pp elastic scattering angular distribution between Pluto samples and experimental data; the acceptance of charged K mesons in the strangeness production channels for the forward region of HPLUS; the
dependence of the maximum energy of photons and the minimum vertex
angle of two photons on the polar angle; the influence on the mass spectrum of excited states of nucleon with large resonant width from different reconstruction methods. It is proved that the Pluto event generator satisfies the requirements of Monte Carlo simulation for HPLUS.
Au-Au碰撞中大横动量双轻子对的产生(英文)
尹睿涛, 傅永平, 李云德#
2011, 28(2): 168-172. doi: 10.11804/NuclPhysRev.28.02.168
摘要:
运用微扰QCD讨论了重离子碰撞中大横动量轻子对的分布, 计算了Au-Au碰撞中两个部分子产生的轻子对的贡献。引入了轻子对产生的直接单光子过程和分解单光子过程。大横动量情况下的所有过程都包括在内, 而且考虑了核遮蔽效应和同位旋效应, 作为QGP背景的双轻子信号有了一个好的修正。The large transverse momentum distribution of lepton pairs produced in heavy-ion collisions has been studied, making use of the perturbative QCD. The contribution of the twoparton production process into lepton pairs in AuAu collisions is calculated. Lepton pair production with the direct single photon process and the resolved single photon process are introduced. We believe that the photon processes are significant. The complete processes at large transverse momentum are included, and moreover, the effect of shadowing and isospin of nucleus are also considered in heavyion collisions. Dilepton signals to regard the background of QGP have a good correction.
高能Pb-Pb碰撞中产生的奇异粒子的横质量分布(英文)
谢文杰, 杨德, 王翠平, 王志刚
2011, 28(2): 173-178. doi: 10.11804/NuclPhysRev.28.02.173
摘要:
基于三火球模型, 用蒙特卡罗方法计算了40和158 AGeV能量下Pb-Pb碰撞中产生的Λ, 和Ξ-强子的横质量分布。在计算中发现射弹核火球、 中心火球和靶核火球在横向有明显的扩展, 并且模型计算的结果与NA49合作组的实验结果相一致。Transverse mass distributions of Λ, , and Ξ- produced in PbPb reactions at
40 and 158 AGeV are described by an expansive threefireball model. A transverse expansion is observed in our calculation. The calculated results, by the expansive threefireball model, are in agreement with the experimental data of NA49 Collaboration.
利用大亚湾中微子实验装置探测超新星中微子
黄明阳, 郭新恒, #, 杨炳麟
2011, 28(2): 179-184. doi: 10.11804/NuclPhysRev.28.02.179
摘要:
在利用大亚湾中微子实验装置研究超新星中微子探测过程中, 需要考虑到中微子传播过程中受到各种效应的影响, 包括超新星震荡效应、中微子集体效应、 MikheyevSmirnovWolfenstein (MSW)效应和地球物质效应等。 由于超新星中微子受到这些效应,
不同味道的中微子之间振荡会发生变化, 因而利用探测某些超新星中微子事例数之比,
就有可能确定中微子的质量层次,得到中微子混合角θ13和中微子绝对质量的信息。
While detecting supernova neutrinos in the Daya Bay neutrino laboratory, several supernova neutrino effects need to be considered, including the supernova shock effects, the neutrino collective effects, the MikheyevSmirnovWolfenstein (MSW) effects, and the Earth matter effects. The phenomena of neutrino oscillation is affected by the above effects. Using some ratios of the event numbers of different supernova neutrinos, we propose some possible methods to identify the mass hierarchy and acquire information about the neutrino mixing angle θ13 and neutrino masses.
非Abel对偶超导理论中的涡旋管研究
王晓云, 邹丽平, 魏智强, 张鹏鸣, #
2011, 28(2): 185-190. doi: 10.11804/NuclPhysRev.28.02.185
摘要:
首次讨论了非Abel对偶超导理论中的涡旋管性质。 在Cho等工作的基础上进一步研究了非Abel情况下的动力学, 并推导出了哈密顿量和运动方程。 重点讨论了限制规范势对应的非Abel对偶超导理论性质, 并给出了D型及N型两类整数涡旋的具体数值解。 通过与传统的Abel对偶超导理论的对比分析,发现两者的运动方程形式及涡旋解基本一致, 这表明利用Abel对偶超导模型研究夸克色禁闭问题是合理的。 We have discussed vortices in the nonAbelian dual superconductor theory.
Based on the work of Cho et al., the Hamiltonian and the equations of motion of nonAbelian model were discussed in details. The nonAbelian dual superconductor theory related to the restricted guage potential was underlined and solutions of Dtype and Ntype integer vortices were obtained. Comparing with the traditional Abelian dual superconductor theory, we found that the the equations of motion and solutions of vortices in two models are almost same, which indicates it is reasonable to study quark confinement based on the Abelian dual superconductor theory.
加速器
高频电压调制对同步运动的影响
刘慧杰, 罗诗裕#, 邵明珠
2011, 28(2): 191-194. doi: 10.11804/NuclPhysRev.28.02.191
摘要:
从系统的扰动Hamiltonian出发, 在经典力学框架内小振幅近似下, 把粒子的纵向运动方程化为Mathieu方程, 指出了由于扰动的存在, 准等时同步加速器出现了一系列新的共振线。用摄动法导出了一阶不稳定区的边界曲线和禁带宽度; 指出了当粒子穿越禁带后的振幅与同步加速器的两个不稳定点相位相等时, 系统处于临界状态; 并由此导出了高频电压调制振幅的临界值。In the classical mechanics frame and small amplitude approximation, the longitudinal motion equation of the particle was reduced to the Mathieu equation based on the perturbed Hamiltonian. It was pointed out that there is a series of new resonance lines in quasiisochronous synchrotron by the perturbation. The boundary curve and the stop width for order instability zone one were derived by the method of perturbabtion. Also it was pointed that the system is at the critical point when the phase becomes equal to the phase of the instable point for the synchrotron after it crossed the stop band, and the critical condition of the high frequency voltage modulation was derived.
核技术
LS301快中子探测器的效率刻度
张文慧, 黎光武, #, 张刚, 陈宇, 闫果红
2011, 28(2): 195-199. doi: 10.11804/NuclPhysRev.28.02.195
摘要:
主要介绍了利用252Cf标准裂变中子能谱刻度快脉冲LS301型液闪中子探测器的探测效率的实验方法和结果, 简要介绍了实验数据的处理过程, 得到了阈值分别为0.5, 0.7, 1.0和1.6 MeV, 以及中子能量在10 MeV以下的探测器效率, 并对测量结果进行了误差分析。同时为了检验实验结果的准确性, 将实验结果与理论计算结果进行比较, 两者在不确定度范围内符合得很好。
Neutron detection efficiency of LS301 fastneutron detector was calibrated by measuring the neutron energy spectrum of 252Cf source, which has a standard fission neutron spectrum. A low mass, fast ionization chamber is used as the fission fragments detector in the timeofflight(TOF) spectrometer and afforded the start signal of neutron flight. The stop signal was offered by the anode of LS301. A measured TOF spectrum was turned to the neutron energy spectrum which will be compared with the standard one. Consequently, the fastneutron detection efficiency of LS301 was obtained. Calibration procedures of experimental and data processing was given. Relative detection efficiencies were obtained separately for threshold settings of 0.5, 0.7, 1.0 and 1.6 MeV for neutron energies under 10 MeV. Experimental results accorded with theoretical efficiency curves which were calculated with the Monte Carlo code NEFF50.
半导体望远镜探测系统研制及其在卫星上的应用
王柱生, 李占奎, 高萍, 谭继廉, 李存璠, 鲍志勤, 卢子伟, 张金霞, 李海霞, 李春艳, 韩励想
2011, 28(2): 200-203. doi: 10.11804/NuclPhysRev.28.02.200
摘要:
简要介绍了由不同厚度的Au-Si面垒和Si(Li)半导体探测器组成的全耗尽带电粒子望远镜系统的制备及其性能,给出了载有该望远镜系统的风云三号卫星(FY-3A)在轨道高度约为830 km辐射区域监测2.9—100 MeV质子和0.15—5.7 MeV电子的结果。
In this paper, the performances as well as the production procedure of the chargedparticle telescope systems consisting of Si(Au) surface barrier detector and Si(Li) detector with different thicknesses were introduced briefly. As an example, the density distributions of the protons and electrons in space detected by the telescope systems mounted on the Fengyun3 satellite (FY3A) were also presented.
提高光子能量沉积计算效率的几种技巧
邱有恒, 应阳君, 王敏, 陈行良
2011, 28(2): 204-208. doi: 10.11804/NuclPhysRev.28.02.204
摘要:
MCNP程序提供了计算光子沉积能的两种方法, 分别是F6和*F8。 当次级电子射程与网格尺度比较接近时, *F8的精度比F6高, 但计算效率比F6低很多。 分析比较了几种提高计算效率的技巧, 分别是: 网格大于10倍电子射程用F6; F6与*F8的联合使用; 改变电子能量子步数; 关掉δ电子; 次级电子自适应截断等。 数值模拟表明, F6与*F8的联合使用以及次级电子自适应截断这两种技巧对精度与效率兼顾得很好。 F6 and *F8 are two methods to calculate energy deposition of photon by MCNP program. If the dimension of grid is almost the same long as the range of secondary electron, the precision of *F8 is higher than that of F6, but the efficiency of F6 is greatly higher than that of *F8. This paper presents five techniques to increase the efficiency,namely: F6 is use to the model with grid dimension bigger than 10 ranges of secondary electron; combination of F6 and *F8; change the substeps of electron; turn off knock on electron; selfadaption cutoff secondary electron. The two techniques, combination of F6 and *F8,selfadaption cutoff secondary electron, can provide a good precision and efficiency.
交叉学科
Kr离子注入SiC的拉曼光谱研究
徐超亮, 张崇宏, 李炳生, 张丽卿, 杨义涛, 韩录会, 贾秀军
2011, 28(2): 209-214. doi: 10.11804/NuclPhysRev.28.02.209
摘要:
应用拉曼光谱研究了5 MeV Kr离子(注量分别为5×1013,2×1014,1×1015 ions/cm2)室温注入6HSiC单晶及其高温退火处理后结构的变化。 研究表明, 注入样品的拉曼光谱中不仅出现了Si—C振动的散射峰, 还产生了同核Si—Si键和C—C键散射峰。 Si—C散射峰强度随退火温度升高而增强, 当退火温度高达1000 ℃时, 已接近未辐照SiC的散射峰强度。晶体Si—Si键散射峰强度随退火温度变化不大, 而非晶Si—Si键散射峰强度随退火温度的增加逐渐消失。相对拉曼强度(Relative Raman Intensity, 简称RRI)随注量的增加逐渐减小并趋于饱和, 且不同退火温度样品的饱和注量不相同; RRI随退火温度的增加逐渐升高, 这在低注量样品中表现得尤为明显。 低、中、高3种注量样品的RRI随退火温度的增加从重合逐渐分离, 并且退火温度越高, 分离越大。 Raman spectroscopy was used to study the structure changes of 6HSiC single crystal implanted with 5 MeV Kr (Krypton) at room temperature and subsequently annealed at high temperature. The Raman spectrum of the implanted SiC displays not only Si—C bonds vibration peaks, but also homonuclear Si—Si and C—C bond vibration peaks. Si—C bond vibration peaks gradually strengthen with increasing temperature. When annealing at 1000 ℃, the peak intensity of Raman spectrum is close to that of virgin specimen. It is found that crystal Si—Si bond vibration peaks do not change when annealing, but amorphous Si—Si bond vibration peaks disappear with increasing annealing temperature. The Relative Raman Intensity (RRI) values decrease with increasing fluence and tend to saturate, but the saturation fluences is different for various anneal temperature. The RRI values increases with raising annealing temperature, which is more obvious in low implanted specimens. At the same time, the RRI values separate gradually with increasing temperature and this phenomenon is strengthened by annealing temperature.

重离子束对北里链霉菌的诱变效应
刘敬, 陈积红, 胡伟, 王曙阳, 李文建, #
2011, 28(2): 215-218. doi: 10.11804/NuclPhysRev.28.02.215
摘要:
考察不同剂量重离子束对北里链霉菌的致死及诱变效应, 可确定最有利于筛选高产菌株的重离子束辐照剂量。 利用不同剂量的重离子束辐照北里链霉菌孢子, 统计了存活率、 致死率、 正负突变率。 结果发现, 在5 Gy重离子辐照时北里链霉菌出现较高致死率, 其后随剂量升高, 致死率变化较平缓。 各辐照剂量下正负突变率相比较, 40 Gy时正突变率最高, 负突变率相对较低, 存活率为0.92%。 因此确定40 Gy是对北里链霉菌高产菌株筛选最有利的辐照剂量。
To define the optimum dose of heavy ion beams for selecting high productive strains, we should study mortality and mutation effects of Streptomyces kitasatoensis irradiated by heavy ion beams in diffe rent doses. In this research, spores of Streptomyces kitasatoensis were irradiated by heavy ion beams with different doses. And survival rate, mortality rate, positive mutation and negative mutation were analyzed statistically. The results showed that high mortality rate appeared from 5 Gy and then the mortality rate curve became gently. Compared the positive and negative mutations in different doses, highest positive mutation was obtained in 40 Gy, while the negative mutation was lower in this dose, and the survival rate was 0.92%. So we defined that optimum dose of heavy ions radiation for Streptomyces kitasatoensis selection was 40 Gy in this experiment.
低能N+ 离子预处理对水稻UV-B辐射的当代损伤效应的影响
赵帅鹏, 黄群策, 陈雪能
2011, 28(2): 219-224. doi: 10.11804/NuclPhysRev.28.02.219
摘要:
采用3种不同注量的N离子对供试材料进行了离子注入预处理, 再用10.08 kJ/(m2d1)增强UV-B辐射对其幼苗进行辐照试验, 测定了过氧化物酶(POD)活性、 过氧化物歧化酶(SOD)活性、 过氧化氢酶(CAT)活性、 丙二醛(MDA)含量、 还原型谷胱甘肽(GSH)含量和可溶性糖含量的变化。 研究结果表明: 经N离子注入预处理的水稻材料受到UV-B辐射时其POD和SOD活性明显升高, 并在注量为2.0×1017 ions/cm2时活性达到最强; CAT活性和MDA含量明显降低, GSH含量显著增加, 而可溶性糖的含量则变化程度很小。 从这些研究结果可以看出, 经过一定注量离子注入预处理的水稻材料当受到UVB辐射时能产生较强的抗氧化能力和防御能力,而且抗氧化系统优于碳水化合物系统而先于表达。 由此可见, 离子注入预处理对水稻UV-B辐射的生物学效应的影响相当明显。 The seedlings of rice (xindao18) were exposed to UVB (10.08 kJ/(m2d1 )) irradiation following the pretreatment with three different implantation dosages of lowenergy N+ ions. Changes in the levels of the superoxide (POD),superoxide dismutase (SOD),catalase (CAT), malondialdehyde (MDA),glutathione (GSH) and soluble sugar were measured. The result showed that the UV-B irradiation on the seedlings of rice pretreated with lowenergy ions implantation could lead to increase activities in POD and SOD,and the maximum appeared on the dose of 2.0×1017 ions/cm2. Meanwhile,it made the content of GSH increased, and caused the activity of CAT and the content of MDA to be decreased. But there was no obvious change in soluble sugar. It was suggested that the rice pretreated by low energy ion implantation could enhance the antioxidation capacity and defensive ability when irradiated by UV-B, and the antioxidation system could be induced earlier than carbohydrate system. Therefore, the biological effects of UV-B irradiation on rice pretreated by low energy ion implantation were quite obvious.
重离子束辐照对荷颊囊癌金黄地鼠血清微量元素的影响
张宝平, 张红, 张晓文, 张格祥, 王小虎, 刘阳, 刘斌, #
2011, 28(2): 225-229. doi: 10.11804/NuclPhysRev.28.02.225
摘要:
探讨了重离子束辐照后荷颊囊癌金黄地鼠血清中微量元素含量的变化趋势。采用0, 4, 6, 8和12 Gy剂量的12C6+ 离子束对荷颊囊癌金黄地鼠辐照治疗后28 d取血, 应用原子吸收光谱仪火焰法测定血清中Fe, Cu, Zn, Mg和Ca 5种微量元素的含量。金黄地鼠成瘤后, 血清中微量Cu, Zn, Ca和Mg元素含量下降, 均明显低于正常组(P<0.05); 不同剂量的重离子束辐照后28 d, 血清中5种微量元素在低剂量时均呈现继续下降趋势, 在6或8 Gy时恢复到正常组水平, 到12 Gy再呈降低的趋势, 存在一定的剂量-反应关系。重离子束辐照影响荷颊囊癌金地鼠血清微量元素的含量, 具有一定的临床意义。
To study the trend of the changes of trace elements in serum of golden hamster with cheek pouch carcinoma after irradiation by heavy ion beam, the cheek pouch carcinoma of golden hamster was exposed to different doses of heavy ion beam, after 4 weeks, the contents of Cu, Zn, Fe, Mg and Ca in serum were detected by flame method of Atomic Absorption Spectrometer. The contents of Cu, Zn, Ca and Mg in experimental groups with cheek pouch carcinoma were significantly lower than that of the normal group (P<0.05). After irradiated by 0, 4, 6, 8, 12 Gy heavy ion beam, the 4 Gy group showed a tendency downward, when the irradiation dose reached 6 Gy, the contents of Fe, Zn were increased, and decreased at 12 Gy. While Cu, Ca and Mg content of 8 Gy group rose to the highest, and decreased at 12 Gy. All of the results showed a dosereaction relationship (P<0.05). The irradiation of heavy ion beam maybe significantly affect the content of trace elements in serum of golden hamster with cheek pouch carcinoma.
辐射诱发体内旁效应特征的研究进展
梁书剑, 张萌, 李文建, 荆西刚, 孙野青, #
2011, 28(2): 230-235. doi: 10.11804/NuclPhysRev.28.02.230
摘要:
大量的细胞生物学研究显示, 辐射诱发旁效应的传输信号包括活性氧自由基(ROS)、 一氧化氮自由基(NO)以及一些细胞因子。 近年来,越来越多的文献报道关于体内旁效应特征的研究, 并已经证实在生物体内辐射诱导的旁效应不仅能发生在相邻组织, 还可发生在远源器官。这些体内旁效应包括DNA损伤、表观遗传学改变、miRNA及基因表达改变、 细胞增殖和凋亡等。 为了总结和分析辐射诱发体内旁效应的特征, 本文综述了辐射诱发体内旁效应的特点, 包括其与性别、 传播途径、辐射品质的关系以及相关机制的研究。
Radiationinduced bystander effect is defined as the induction of damage in neighboring nonhit cells by signals released from directlyirradiated cells. ROS, NO and cytokines are involved in signaling pathways of bystander effects. Recently, the bystander effects in vivo have been reported more and more. It has been indicated that radiation induced bystander effect was localized not only in bystander tissues but also in distant organs. This effect includes many biological endpoints such as DNA damage, epigenetic, miRNA and gene expression changes, cell proliferation and apoptosis. In this review we described different aspects of ionizing radiationinduced bystander effects such as its characteristics, sex specific, signaling transfer, dose and LET dependence, and related mechanisms.
MCNP Dose Calculations in a CT Phantom for Therapeutic External Photon Beam
Lamyae El Gonnouni, Tarek El Bardouni, Mariam Zoubair, Mohamed Idaomar, Abderrahmane Senhoo
2011, 28(2): 236-240. doi: 10.11804/NuclPhysRev.28.02.236
摘要:
In this paper, we have addressed the problem of the radiation transport with the Monte Carlo Nparticle(MCNP) code. This is a generalpurpose Monte Carlo tool designed to transport neutron, photon and electron in three dimensional geometries. To examine the performance of MCNP5 code in the field of external radiotherapy, we performed the modeling of an Electron Density phantom (EDP) irradiated by photons from 60Co source. The model was used to calculate the Percent Depth Dose (PDD) at different depths in an EDP. One field size for PDD has been examined. A 60Co photons source placed at 80 cm source to surface distance (SSD). The results of calculations were compared to TPS data obtained at National Institute of Oncology of Rabat.
超短超强激光脉冲作用下的Mo等离子体X射线辐射(英文)
徐秋梅, 杨治虎, #, 杜树斌, 杨兆锐
2011, 28(2): 241-244. doi: 10.11804/NuclPhysRev.28.02.241
摘要:
在SILEX-1激光器上,利用光子计数型CCD测量了超短超强激光束与高纯度Mo相互作用而产生的发射谱。实验发现, 在超短超强激光脉冲作用下, Mo等离子体辐射Kα X射线, 这一过程伴随很强的热辐射和轫致辐射。Mo等离子体Kα X射线辐射强度、 热辐射和轫致辐射随激光功率密度增加而增强。Using a Singlephotoncounting CCD, Xray emission spectra of high purity Mo irradiated by ultrashort and ultraintense laser pulse was firstly detected. The experiment was carried out with the SILEX1 laser facility. The experimental results show that, for Mo target, characteristic Kshell emission (Kα) is observed in the 0.23—2.32 J energy range in addition to a broadband bremsstrahlung background, and the Xray radiation intensity, thermal radiation and bremsstrahlung increase with enhancementofthe laser power density.
高离化态Au离子光电离过程的理论研究
王云荣, 刘晓斌, 丁晓彬, 董晨钟#
2011, 28(2): 245-250. doi: 10.11804/NuclPhysRev.28.02.245
摘要:
基于多组态Dirac-Fock方法的程序包GRASP92和RATIP及在此基础上最新发展的RELPHOTO08程序, 系统地研究了高离化态金离子M壳层的光电离截面随入射光子能量、 离化度以及壳层的变化规律。结果表明: 光电离截面随光子能量的增大而单调减小; 电离nl电子时, 如果相关电子的主量子数较大, 则该电子存在与否对其光电离截面几乎没有影响; 在同一离化度下, 角量子数l可引起两种性质不同的效应, 其相互竞争可导致光电离截面随入射光子能量的复杂变化。Based on multiconfiguration DiracFock method and the corresponding packages GRASP92 and RATIP, as well as the newly developed RELPHOTO08, the variations of M subshell photoionization cross sections with the photon energy, ionization degree and subshells for highly charged gold ions are studied systemically. The present results show that the cross sections are decreasing monotonously with the photon energy; for the photoionization of nl electrons, if the principal quantum number of removed electron is large enough, the cross sections are essentially unchanged upon the presence or absence of outer electrons; for same ionization degree, the angular quantum number introduces two opposite effects which could exist simultaneously, and the intricate variations of cross sections with the photon energy originate from the competition between these two different effects.
核能与核数据
15N(p, n)15O反应中子源0°角激发函数测量
齐波, 阮锡超, #, 姚泽恩, R.Nolte, 陈国长, 黄翰雄, 李永明, 周斌, 马中原, 张雅玲, 仲启平, 聂阳波, 陈效先, 周祖英
2011, 28(2): 251-255. doi: 10.11804/NuclPhysRev.28.02.251
摘要:
利用中国原子能科学研究院HI-13串列加速器上的多探测器快中子飞行时间谱仪, 测量了38个不同入射质子能量点下15N(p, n)15O反应0°角方向的激发函数。 测量数据用蒙特卡罗方法进行了模拟, 以进行中子注量衰减和入射窗厚度的不确定度修正。 实验在入射质子能量位于6.029—8.056 MeV之间时发现了3个共振峰, 这一点与DROSG2000评价数据及PTB数据相符合, 但三家的截面数值存在差异, 对这些差异需要作进一步深入探讨。 The excitation function of 15N(p, n)15O reaction at 0 degree was measured at 38 energy points using the fast neutron TimeofFlight (TOF) spectrometer at the HI13 Tandem Accelerator in the China Institute of Atomic Energy(CIAE). The measured data were analyzed by MonteCarlo simulation for the corrections of neutron flux attenuation and uncertainty of the thickness of the entrance foil. Three resonance peaks were observed in this experiment in the energy range from 6.029 to 8.056 MeV,which is comparable with the DROSG2000 evaluated data and the PTB data. However,more experimental studies are needed since the cross sections deviate with each other.