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Segmented HPGe平面型位置灵敏探测器阵列的γ成像分析；Gamma-ray imaging analysis by using array of segmented planar HPGe detectors
No full text探测器位置分辨能力的高低是实现γ成像的一个重要指标.Segmented HPGe平面型位置灵敏探测器能够很好地给出γ射线与探测器晶体相互作用的作用点位置信息.利用由这种探测器组成的探测器阵列对~(22)Na标准源进行了γ成像实验.结果能够区分出标准源两个不同的摆放位置的细微差别,并与实际情况符合得很好.从而检验了Segmented HPGe平面型位置灵敏探测器的位置分辨能力
THE DESIGN OF TRANSVERSE EMITTANCE MEASUREMENT
No full textHIRFL-CSR is a multi-purpose heavy ion storage ring<br />in Lanzhou. In order to measure the transverse emittance<br />of the injected beam on the transfer channel to the<br />HIRFL-CSR, two kinds of emittance measurement<br />devices which included pepper- pot and slit-grid were<br />proposed. The pepper-pot is unique in providing an<br />instantaneous measurement of the two-dimensional<br />emittance of a beam. The data acquired by this method is<br />only an image. The slit-grid is a one dimensional<br />emittance measurement device. During the measurement,<br />the slit, driven by the stepper motor is moved stepwise<br />across the beam, and then the signal induced on the grid<br />will be stored in the computer for further analysis.<br />Because slit-grid is one dimensional device, two sets of<br />this device are needed for transverse measurement. In this<br />paper, we introduce the design, parameters, data<br />acquisition and analysis of these two methods. Especially<br />the software integration is given in this paper. Main<br />interest is directed on the software development for<br />emittance front-end control and data analysis such as<br />evaluation algorithms
ACTIVATION OF A 250 MEV SC-CYCLOTRON FOR PROTON THERAPY
No full textBeam losses in dedicated 230-250 MeV cyclotrons for<br />proton therapy cause radioactivity in machine parts. A<br />systematic study has been performed of the activation of<br />PSI’s 250 MeV SC-cyclotron for proton therapy. Since<br />the start of the cyclotron operation dose rate<br />measurements have been made as a function of time at<br />several locations in and around the cyclotron. Gamma ray<br />spectra have been measured of selected iron inserts in the<br />pole and of copper disks in the liner of the RF system.<br />The isotopic composition of the activation has been<br />derived and compared with activations calculated with<br />Monte Carlo calculations (MCNPX). The data and beam<br />history of the cyclotron allow predictions of the dose rate<br />during service activities shortly after beam interruption as<br />well as after a specified period of operation
Decomposition of the gauge potential and the topological structure of Chern-Simons vortices solution
No full text本论文主要包括两部分内容，一部分简述了规范势的可分解理论，第二部分研究了Chern-Simons涡旋解的拓扑结构。讨论了SU(2)规范势分解的几何意义。提出了非对易规范势的可分解性，求出了非对易 群规范势用单位矢量场的分解以及规范平行条件下的规范场强。利用规范势分解理论和Ф-映射拓扑流理论分别研究了Jackiw-Pi模型和SU(2)Dunne-Jackiw-Pi-Trugenberger模型涡旋的拓扑结构，得到一个新的自对偶方程，发现了Chern-Simons多涡旋解与拓扑数之间的联系。我们构造了一个新的静态的自对偶Chern-Simons多涡旋解，每个涡旋由5个实参数描述。为了研究拓扑数对涡旋形状的影响，给出了具有不同拓扑数的多涡旋解，并绘出了涡旋密度的分布图。我们还研究了该涡旋解的磁通量的拓扑量子化本论文主要包括两部分内容，一部分简述了规范势的可分解理论，第二部分研究了Chern-Simons涡旋解的拓扑结构。讨论了SU(2)规范势分解的几何意义。提出了非对易规范势的可分解性，求出了非对易 群规范势用单位矢量场的分解以及规范平行条件下的规范场强。利用规范势分解理论和Ф-映射拓扑流理论分别研究了Jackiw-Pi模型和SU(2)Dunne-Jackiw-Pi-Trugenberger模型涡旋的拓扑结构，得到一个新的自对偶方程，发现了Chern-Simons多涡旋解与拓扑数之间的联系。我们构造了一个新的静态的自对偶Chern-Simons多涡旋解，每个涡旋由5个实参数描述。为了研究拓扑数对涡旋形状的影响，给出了具有不同拓扑数的多涡旋解，并绘出了涡旋密度的分布图。我们还研究了该涡旋解的磁通量的拓扑量子
含砂率计
No full text本实用新型涉及一种含砂率计，该砂率计是在砂浆管壁的径向对称位置分别通过射线发生器固定架和探测器固定架设有射线发生器和探测器，在射线发生器和探测器前均设有光栏，在射线发生器的光栏前还设有射线发生器防护活塞阀，在射线发生器的两侧分别设有前屏蔽块和后屏蔽；探测器的输出信号与探测器辅助电路相连；本实用新型为外卡式非接触γ射线测量，其测量精度高、测量范围大，可连续在线测量。本实用新型涉及一种含砂率计，该砂率计是在砂浆管壁的径向对称位置分别通过射线发生器固定架和探测器固定架设有射线发生器和探测器，在射线发生器和探测器前均设有光栏，在射线发生器的光栏前还设有射线发生器防护活塞阀，在射线发生器的两侧分别设有前屏蔽块和后屏蔽；探测器的输出信号与探测器辅助电路相连；本实用新型为外卡式非接触γ射线测量，其测量精度高、测量范围大，可连续在线测量
相对论连续无规位相近似研究流和库仑相互作用对核巨共振激发的影响
No full text<正>在相对论连续无规位相近似(RCRPA)框架下研究了矢量介子流和库仑相互作用对核多极激发的影响。在这个方法中,用单粒子格林函数方法严格处理连续态对粒子-空穴(ph)激发的贡献。在无海近似下,单粒子格林函数中同时包含了狄拉克海负能态。数值计算中,单粒子格林函数由狄拉克方程的正规解和非正规解的适当乘积得到。我们采用完全自洽的RCRPA计算,即在同一个拉氏量下描述核基态性质和ph相互作用,这里,我们选用参数NL3。矢量介子空间分量即流虽然
外源激素对马铃薯试管苗耐盐性的影响
No full text以马铃薯栽培品种甘农薯2号试管苗为试材,研究了在0.4%、0.6%NaCl胁迫下外源激素GA3、6-BA、IAA对试管苗耐盐性的影响。结果表明:3种激素均对马铃薯试管苗受到的盐胁迫具有一定缓解作用,使盐胁迫下的试管苗叶绿素含量提高、脯氨酸和丙二醛含量降低,其中GA3和IAA提高叶绿素含量的效果显著,GA3降低脯氨酸和丙二醛含量的效果比6-BA和IAA明显
System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio
No full textBased on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the pi(-)/pi(+) ratio in the following three reactions: Ca-48+Ca-48, Sn-124 +Sn-124 and Au-197+Au-197 with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 A GeV. It is shown that the sensitivity of probing the E-sym (rho) with pi(-)/pi(+) increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior Of nuclear symmetry energy at supra-saturation densities
Shell effect on stabilization processes following multi-electron transfer in slow Arq+-Ar (g=6-9, 11) collisions
No full textWe experimentally investigate the shell effect on the stabilization processes following the multi-electron transfer in slow collisions of Arq+-Ar (q = 6-9, It) The relative cross-section ratios of multi-electron transfer and of the subsequent stabilization with respect to single-electron capture are measured meanwhile compared with the theoretical results predicted by the classical over-barrier model. Our result indicates that the multi-electron transfer is dominant when the projectile charge is large and the subsequent stabilization shows a dramatic variation if the projectile L-shell configuration becomes open. It shows that the subsequent stabilization processes of multiply excited scattering ions have a strong dependence on the projectile shell. (C) 2010 Elsevier BV All rights reserved
Measurement of the Bottom Quark Contribution to Nonphotonic Electron Production in p plus p Collisions at root s=200 GeV
No full textThe contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at root s = 200 GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of p(T) >= 5 GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high p(T)