125Cs的能级结构

通过116Cd(14N,5n),Ebeam=65MeV的核反应布居了125Cs的高自旋态.利用在束γ谱学实验方法,进行了γ-γ符合测量,使已知的125Cs核能级纲图得到了扩展,并且修正了某些组态的带头激发能.High-spin states in odd-A nucleus~(125)Cs have been studied via the~(116)Cd(~(14)N, 5n) reaction at 65 MeV bombarding energy. γ-γ coincidences were recorded with the NORDBALL detector array at Niels Bohr Institute in Denmark. After careful data analysis, most of the previously-known bands have been confirmed and 5 new rotational sequences have been identified. Spin/parity and configuration assignments are tentatively proposed for all of the observed bands. In addition, the bandheads of the 9/2~(+)and (1/2~...     

碰撞能量转移Cs(6P)+Cs(5D)→Cs(6S)+Cs(nL=9S,5F)的截面测量

二步激发Cs原子至8S态,测量了碰撞转移过程Cs(6P)+Cs(5D)→Cs(6S)+Cs(nL=9S,5F)的截面,测量由7D,9S和5F态发射的荧光强度,从荧光强度比和σ(7D)值得到了σ(9S)和σ(5F),而σ(7D)已经进行过绝对测量,截面值σ(9S)和σ(5F)分别为8.7×10-15和1.3×10-14?cm2.讨论了能量转移过程9S+6S5F+6S对σ(9S)和σ(5F)的影响.     

Dasβ-Spektrum des Cs137

Theβ-ray spectrum of Cs¹³⁷ has been measured with an iron-free spectrometer. The energy of the soft component was found to beE ₀=514±2 keV. The parameterk of the hard-component shape factorC _2VA ⁽²⁾ (W)=q ²+kp ² was determined to bek=0.015±0.004. Theβ intensities amount to 6.5% (hard component) and 93.5% (soft component). TheK conversion coefficient of the isomeric transition was measured to beα _K=0.093±0.003, in excellent agreement withSliv's theoretical value.     

激发态Cs原子间碰撞能量转移截面

在Cs蒸气密度为1013?cm-3量级范围内,研究了6P3/2+6P3/2→6DJ+6S碰撞能量合并过程.利用单模半导体激光器共振激发6P3/2态,利用另一与泵浦激光束反向平行的单模激光束作为吸收线探测激发态原子密度及其空间分布,吸收线调至6P3/2→8S1/2跃迁,并可平行于泵浦激光束移动.由激发态原子密度和谱线的荧光强度比得到碰撞能量合并的截面.碰撞转移到6D5/2和6D3/2的截面分别是(4.1±1.8)×10-15和(2.2±1.0)×10-15?cm2.与其它实验结果进行了比较.     

Cs2分子的光解光谱

利用He-Cd激光器的441.6 nm线光解Cs2分子, 使Cs(n2L)(nL=7P, 6D)态得到布居, 在Cs密度1到9×1015 cm-3范围内测量原子荧光对分子荧光强度比, 得到碰撞转移率系数对解离率之比分别为2.9×10-17和7.4×10-18 cm3. 测定Cs nLJ对nLJ'荧光分支比, 得到72P, 62D态精细结构解离率之比分别为0.53和0.43. 从远翼激发得到的精细结构转移截面与从其他激发过程得到的截面结果相符, 给出了碰撞转移到6D态外(即Cs(6D)+Cs(6S)→Cs(6D)以外的态)的截面为1.9×10-14 cm2.     

Saturation of Photoassociation in Cs Magneto-optical Trap

An ultrahigh resolution photoassociation spectrum of caesium atoms in a magneto-optical trap is presented. Hyperfine structure of the excited state molecule is obtained by using the lock-in method based on modulated cold atoms in this spectrum. Amplitude of resonant lines related to the rotational levels increases with photoassociation laser intensity, and saturation effect of photoassociation of cold atoms is observed in our experiment. The saturation intensity of photoassociation is deduced by fitting the experimental data to asaturation model based on scattering theory. Differences among saturation intensities of different rotational progressions in the υ=55 vibrational state of the caesium molecular long-range 0_g^- state have been found.     

渗入Cs的沸石的结构分析

20 0 2年 8月 12日的Ｐｈｙｓ .Ｒｅｖ .Ｌｅｔｔ.第 89卷第 0 75 5 0 2页上发表了Ｐｅｔｋｏｖ等的论文“渗入Ｃｓ的ＩＴＱ - 4沸石 (Ｚｅｏｌｉｔｅ)的结构 :在膺一维空隙中的金属离子列和相关的电子” ,文中发展了Ｘ射线原子对分布函数 (ＰＤＦ)方法 .这种结构可以发展成为应用广泛的新的电极材料 .沸石ＩＴＱ - 4是一种由ＳｉＯ4四面体为骨架的网格状硅酸盐 ,其中的空隙尺寸略小于1ｎｍ ,允许尺寸小于它的分子通过 ,因此它也是一种分子筛 .沸石原来是晶态 ,渗入Ｃｓ后则处于晶态和非晶态之间的中间状态 ,其中的晶态部分产生Ｘ射线布拉格…     

Cs原子459nmFADOF特性分析

本文计算了Ｃｓ原子４５９ｎｍ的法拉弟反常散滤光器ＦＡＤＯＦ的一些重要特性，结果表明：Ｃｓ原子ＦＡＤＯＦ在某一恒定的泡温和一定的磁场范围内，具有基本稳定的透过率和线宽以及线性的频率调谐。     

Cs2分子的光解离和碰撞能量转移

利用He-Cd+激光器的441.6 nm线光解Cs2分子,使Cs(6D)态得到布居,在Cs2密度为1～9×1015 cm-3范围内,测量原子荧光对分子荧光强度比,得到碰撞转移率系数对解离率之比为9.6×10-18 cm3.测定Cs(6D3/2)对6D5/2荧光强度分支比,得到62D态精细结构能级解离率之比为0.41.从翼激发得到的精细结构转移截面与从共振激发得到的截面结果相符.     

激光诱导Cs(6P)和Cs(9D)态布居数变化的荧光检测

在Cs蒸气中观察了荧光强度的增强与减弱.6P3/2态荧光的减弱是由于激光激发6P3/2→9D5/2的跃迁造成的,9D5/2态原子碰撞转移到9D3/2,产生9D3/2→6P1/2的辐射,增加了6P1/2态的布居,从而使6P1/2→6S1/2的荧光增强.激光诱导布居数的变化由相应荧光的强度信号的增减来检测,利用速率方程组,得到了受激发射(即9D5/2→6P3/2)速率为3.0×106?s-1,精细结构碰撞转移(即9D5/2→9D3/2)速率为1.1×106?s-1.     

Evaluation of Transmutation of ^137Cs（γ, n） 136Cs Using Ultra-Intense Lasers in Solid Targets

Relativistic electrons produced in ultra-intense laser-solid interaction generate highly collimated γ-ray beams through Bremsstrahlung that can be used to induce photonuclear reactions. Photonuclear transmutation （of （% n） type） of ^137 Cs, one of the hazardous nuclear wastes with half-life of 30.17 years which cannot be transmuted practically with neutron bombardment due to its very low neutron capture cross section, has been considered. Nuclear activity of produced 136Cs with half-life of 13.16 days has been evaluated analytically using available experimental data. With irradiating a ^137Cs sample by p-polarized laser light of 10^20 Wcm^-2 and the repetition rate of 10Hz for 30min, the activity of 0.24 Bq is obtained. It is found that intensity has a large effect in yield around 10^21 Wcm^-2. For similar laser with intensity of 5 ×10^21 Wcm^-2, the activity increases with a factor of 10^5.     

Cs(6DJ)+Cs(6S1/2)非弹性碰撞转移截面的测定

在9×1014～2.1×1015cm-3 Cs密度范围内,利用脉冲激光双光子激发Cs(6S1/2)到Cs(6D5/2)态,使用原子荧光光谱方法,通过三能级模型的速率方程分析,由对直接荧光和转移荧光的时间积分强度的测量,得到6D5/2→6D3/2精细结构转移截面为(2.1±0.4)×10-14cm2,而6D3/2态向6D以外态的转移截面为(1.6±0.4)×10-14cm2,它应是过程Cs(6 D3/2)+Cs(6S)→Cs(6P)+Cs(6P),6D3/2→7P3/2和6D3/2→7 P1/2碰撞转移截面之和.第二个实验可以得到6 D3/2→7P3/2和6D3/2→7 P1/2的碰撞转移截面.在1×1012～6×1012cm-3的低密度Cs蒸气中,激光双光子激发6S至6D3/2或6D5/2态,测量6DJ→6PJ'与7PJ"→6S1/2的时间积分荧光强度比,得到6D3/2→7P1/2与6D5/2→7R3/2的碰撞转移截面分别为(7.6±2.4)×10-15cm2与(1.6±0.5)×10-15cm2.由此得到碰撞能量合并的逆过程即[Cs(6D3/2)+Cs(6S1/2)→Cs(6P)+Cs(6P)]的转移截面为(1.3±0.4)×10-14cm2.     

高温Cs激活GaAs光电阴极表面机理研究

研究了高温Cs激活过程中,GaAs光电阴极表面势垒的变化机理。在考虑GaAs材料体内负电性p型掺杂杂质与材料表面正电性Cs+所形成的偶极子对表面势垒的作用后,通过求解均匀掺杂阴极中电子所遵循的一维连续性方程,得到了反射式均匀掺杂阴极的量子效率公式,通过求解薛定谔方程得到了到达阴极表面的光电子的逸出概率公式,利用公式对GaAs光电阴极的Cs激活过程进行了分析。分析发现,激活过程中GaAs光电阴极的量子效率和光电子的逸出概率正比于偶极子层的电场强度。     

Internal bremsstrahlung of the unique 137Cs β decay

The internal bremsstrahlung differential spectra of the singly forbidden unique ¹³⁷Cs β transition have been experimentally studied at different angles between the escape directions of electrons and γ photons. The measurements were performed on a β-γ-coincidence spectrometer with an effective collimator.     

激发态Cs(5D)原子间碰撞能量转移

用激光二步激发Cs原子至8S态,从谱线的波长及强度可以确定Cs原子的辐射及碰撞过程,5D态主要是由8S→7P→5D跃迁布居的.在1016-1017Cs密度范围内,测量了碰撞能量合并5D 5D→nL 6S(nL=9D,11S,7F)速率系数,因5D→6P(3.0-3.6μm)处于红外本实验不能探测,利用一个已经测量过的过程(即6P 5D→6S 7D)作相对测量,对于9D,11S和7F态,其平均速率系数分别为(8.4±4.2)×10-10,(7.3±3.6)×10-10和(9.7±4.8)×10-10cm3s-1.讨论了碰撞转移过程11S 6S 7F 6S对速率系数的影响.