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根据BaF2晶体闪烁光快、慢成分波段的不同,设计并制备了用于抑制该晶体闪烁光慢成分的Al2O3/MgF2/Al/MgF2…光子带隙膜系。实验结果显示:加载光子带隙膜系的BaF2晶体,其闪烁光快/慢成分比提高80倍以上;经剂量为1×105 Gy的60Co γ射线辐照后,其透射光谱、发射光谱和发光衰减时间谱没有明显的变化,这表明由光子带隙膜系与BaF2晶体所构成的快闪烁器件不仅可有效避免慢成分的干扰,而且还具有很强的抗γ辐射性能。 相似文献
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Mg:Fe:LiNbO3晶体的生长及光学性能研究 总被引:6,自引:6,他引:0
在Fe:LiNbO3中掺进MgO和Fe2O3以提拉技术生长Mg:Fe:LiNbO3晶体.对晶体进行极化和还原处理.测试晶体的吸收光谱,Mg:Fe:LiNbO3晶体吸收边相对Fe:LiNbO3晶体发生紫移.测试晶体的红外光谱,Mg:(5 mol%)Fe:LiNbO3晶体OH-吸收峰由Fe:LiNbO3晶体的3482 cm-1移到3534 cm-1.采用锂空位模型阐述Mg:Fe:LiNbO3晶体,吸收边和OH-吸收峰移动的机理.测试晶体的抗光致散射能力.Mg:(5 mol%)Fe:LiNbO3晶体抗光致散射能力比Fe:LiNbO3晶体提高一个数量级以上.测试晶体的衍射效率和响应时间.Mg:Fe:LiNbO3晶体响应速度比Fe:LiNbO3晶体提高四倍. 相似文献
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In∶Nd∶LiNbO3晶体倍频性能的研究 总被引:1,自引:1,他引:0
在 LiNbO3中掺进In2O3和Nd2O3, 以Czochralski技术生长了In∶Nd∶LiNO3晶体. 通过光斑畸变法测得In∶Nd∶LiNbO3晶体的光损伤阈值为1.98×104 W/cm2, 比Nd∶LiNbO3晶体的1.6×102 W/cm2高两个数量级以上;晶体吸收光谱的测试表明, In∶Nd∶LiNbO3晶体的吸收边相对Nd∶LiNbO3晶体发生紫移. 研究了In∶Nd∶LiNbO3晶体的倍频性能, 结果表明, In∶Nd∶LiNbO3晶体的相位匹配温度在室温附近, 倍频转换效率比Nd∶LiNbO3晶体提高二倍. 相似文献
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本文描述了北京谱仪BES主漂移室一个多层多单元模型的结构, 给出在日本KEK12GeV质子同步加速器K2试验束上, 利用动量0.5~1.5GeV/c的e+,π+和p束测量模型性能的主要结果. 在3.1cm的单元半宽内, 室的单丝空间分辨率σx=170~210μm. 相当四十次dE/dx取样的能量分辨率σE/E约为15%, 提供了北京谱仪工作能区鉴别粒子的一种有效方法, 可同飞行时间(TOF)计数器和簇射计数器相互补充. 相似文献
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Co2+:ZnAl2O4晶体电子光谱及其2E态双重谱线结构的Jahn-Teller效应研究 总被引:5,自引:3,他引:2
在中间场耦合图象中,利用Racak不可约张量算符法和Wigner-Eckart定理,建立了3d7(C3v)电子组态的完全能量矩阵;利用该矩阵研究了Co2+:ZnAl2O4晶体的电子光谱,理论与观测十分吻合.首次定量地解释了2E态的双重谱线结构,并从理论上预言了4A2基态2.93cm-1的零场分裂(ZFS).研究结果定量地表明,Jahn-Teller效应所致Co2+:ZnAl2O4晶体Co2+中心局域结构的畸变假设是合理的. 相似文献
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Shanghai Laser Electron Gamma Source, a high intensity beam line of γ-ray, is expected to generate γ-rays up to the maximum energy of 22 MeV by Compton backscattering between a CO2 laser and electrons in the 3.5 GeV storage ring of the Shanghai Synchrotron Radiation Facility. The luminosity of SLEGS γ-ray beam is estimated to be 7×107 A-1W-1s-1 in a optimized setup. Indirect measurement of cross section of the key nuclear-astrophysics reaction 12C(α,γ)16O and γ-ray-triggered transmutation of long-lived radioactive wastes are discussed based on the estimated SLEGS γ-ray beam properties. 相似文献
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High spin states in 107Ag are studied via the 100Mo(11B, 4n)107Ag reaction at an incident beam energy of 60 MeV. Prompt γ-γ coincidence and DCO ratios are measured by the detector arrays in CIAE. The level scheme has been updated and a new negative band belonging to 107Ag is identified. The new negative side band has been constructed and its configuration is tentatively assigned to πg9/2 νh11/2(g7/2/d5/2). 相似文献
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High-spin yrast structures of even-even superheavy nuclei 254-258Rf are investigated by means of total-Routhian-surface approach in three-dimensional (β2, γ, β4) space. The behavior in the moments of inertia of 256Rf is well reproduced by our calculations, which is attributed to the j15/2 neutron rotation-alignment. The competition between the rotationally aligned i13/2 proton and j15/2 neutron may occur to a large extent in 256Rf. High-spin predictions are also made for its neighboring isotopes 254,258Rf, showing that the alignment of the j15/2 neutron pair is more favored than that of the i13/2 proton pair. 相似文献
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The high spin states of 129Ce have been populated via heavy-ion fusion evaporation reaction 96Mo (37Cl, 1p3n) 129Ce. The γ-γ coincidence and intensity balance used to measure the B(M1; I→I-1)/B(E2; I→I-2) (the probability ratio of the dipole and quadrupole transition) in ν7/2[523] rotational band of 129Ce. And the energy splitting (Δe′) has been got through the experimental Routhians. The lifetimes and quadrupole moments Qt have been extracted from the lineshape analyses using DSAM. The deformation of the ν7/2[523] rotational band of 129Ce was extracted from the Qt and moment of inertia JRR. 相似文献
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A thick natural uranium target was bombarded with a 60 MeV/u 18O beam. The neutron-rich isotope 230Ra as the target residue was produced through the multinucleon transfer reaction(238U-4p-4n). The barium and radium fraction as BaCl2 precipitate were radiochemically separated first from the mixture of uranium and reaction products. Then, the radium fraction was separated from BaCl2 precipitate by using cation exchange technique. The γ-ray spectra of the Ra fraction were measured using an HPGe detector. The production cross sections of 230Ra were obtained by a combination of the radiochemical separation technique and off-line γ-ray spectroscopy. The cross section of 230Ra has been determined to be 66±20 μb. 相似文献
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本文指出, 无质量Bose子和Kerr-Newman黑洞不形成束缚态. 有质量的Bose子, 在0<α<√M2-Q2的情况下, 若E≠am+eQr+/2Mr+-Q2则无束缚态; 若E=am+eQr+/2Mr+-Q2则非束缚态存在的必要条件是(22)和(24)式. 在a=√M2-Q2的情况, 束缚态的能量E=√M2-Q2+eQM/2M2-Q2, 当Q=0或者e=0时, 本文结论与de Felic[1]和章世伟、苏汝铿[2]的结果相符. 相似文献
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国产锗酸铋(BGO)闪烁体定时性能的研究 总被引:1,自引:0,他引:1
用与单电子脉冲平均高度相比较的方法测得国产BGO试制样品在特定条件下的光电子产额为687/MeV;在一套β-γ符合的时间谱仪上研究BGO光脉冲形状,表明主要有两种发光成份,寿命为τ1=60ns成份的相对强度I1占9%左右,成份τ2=310ns的相对强度I2占86%,此外,似乎还存在一个寿命约1.2μs强度很弱的成份;使时间谱仪于γ-γ符合方式下工作,起始道为NE111-XP2020塑料闪烁计数器,停止道为小体积BGO-XP2020计数器,测60Co两γ射线瞬时符合分辨曲线,得到在E≥1MeV下系统时间分辨率FWHM=0.70ns.以上测量结果与国产NaI(TI)及国产塑料闪烁体ST401的测量结果作了对照. 相似文献
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车兴来 朱胜江 J.H.Hamilton A.V.Ramayya J.K.Hwang 李明亮 禹英男 I.Y.Lee J.O.Rasmussen Y.X.Luo 《中国物理 C》2004,28(Z1)
通过对重核252Cf自发裂变产生的瞬发γ谱的测量, 对丰中子核108Ru的能级结构进行了研究. 基带、单声子γ振动带和一个二准粒子带分别得到了确认和扩展, 同时识别了一个新的边带, 初步认定为二声子γ振动带. TRS模型计算表明108Ru核具有三轴形变,其形变参量为β2~0.29, γ=-22°. 推转壳模型的计算结果表明108Ru核基带回弯是由h11/2轨道的一对中子发生角动量的顺排所致. 对二准粒子带的组态特性也进行了讨论. 相似文献
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采用压力光谱技术在低温下观测到了Mn2+离子的4T1→6A1跃迁,该谱线在Zn0.83Mn0.17Se和ZnSe/Zn0.84Mn0.16Se超晶格样品中有不同的压力行为,体材料中其压力系数为-42.4 peV/Pa,超晶格中为-29.5 peV/Pa。用晶体场理论计算得到体材料Zn0.83Mn0.17Se中Mn2+离子4T1→6A1谱线的压力系数为-38.3 peV/Pa,与实验结果基本一致。结合材料中发光峰积分强度随压力的变化关系进行分析,证实Mn2+离子的发光性质主要与其近邻的晶体场环境有关。 相似文献