LaBr_3:Ce~(3+)闪烁晶体研究进展

以铈离子Ce3+激活的LaBr3晶体(LaBr3:Ce3+)是近年来发现的一种新型无机闪烁体材料,较高的光产额、较好的能量分辨率、较快的衰减时间等优良性质,使其成为NaI(Tl)等传统闪烁体材料有力的竞争者。论文通过重点比较LaBr3:Ce3+晶体与NaI(Tl)晶体的性质,同时列举实例说明它的应用,力求比较全面地反映LaBr3:Ce3+晶体的性质。     

新型闪烁剂P-TTD的测试

上海试剂一厂试制的新型第一闪烁剂2,5-二(对-甲基苯基)噁二唑-1,3,4(简称P—TTD),以对甲苯甲酸和水合肼为原料,经催化一步合成。 1974年,美国Mark Hymax Jr提出2,5-二(间-甲基苯基)噁二唑-1,3,4(简称M-TTD)因具有相对输出脉冲高度(RPH)高、溶解度大的特性,为一理想的第一闪烁剂,并于1976年获准专利权后发表。     

Effect of yttria substitution on the light output of (Gd,Y)2O3:Eu ceramic scintillator

For the application of the computed tomography (CT) scanner, Gd_1.94−xY_xEu_0.06O₃ ceramic scintillator was prepared. We investigated the effect of the relative contents of Y₂O₃ for Gd₂O₃ matrix on the light output properties by the measurements of the emitted light spectra, relative light output, and X-ray diffraction (XRD) patterns. From the measurement results, it was found that maintaining the crystalline structure as cubic phase after sintering process is important to achieve high light output properties on (Gd,Y)₂O₃ ceramic scintillators, and the scintillation conversion process is more dominant for high light output of cubic phase than the optical transparency.     

二氯苯基二硫代膦酸萃取Am~(3+)和三价镧系元素的研究

研究了二氯苯基二硫代膦酸 (DCPDTPI)对示踪量Am3+ 和Eu3+ 的萃取。实验结果表明 ,此萃取剂优先萃取Am3+ ,当萃取剂浓度为 0 1mol/L ,pH =2 73时 ,最大的分离因数β(Am3+ /Eu3+ ) max=8。用ICP MS法同时测定了DCPDTPI对除钷以外的所有镧系元素的萃取分配比 ,并计算了Am3+ 与这些元素的分离因数     

LaCl3:Ce3+闪烁体正电子湮没寿命谱仪

对国内最新研制出的LaCl3：Ce^3＋闪烁晶体时间特性进行了测试,用该种晶体尝试组建了正电子湮没寿命谱仪,时间分辨率达到了350ps。由于LaCl3：Ce^3＋探头在具有快速时间响应特性的同时还具有较高的能量分辨率,用该探头组建正电子湮没寿命谱仪将具有许多潜在的优势。     

新型无机闪烁体CeF3的时间特性研究

CeF3是新型快响应无机闪烁体．对近年国内研制的CeF3无机闪烁体的时间特性进行了研究,包括脉冲辐射诊断所关心的CeF3对快脉冲γ辐射源的时间响应．如上升时间、半高竟、脉冲后沿;同时推算并使用了用脉冲法获得晶体发光衰减常数的简单估算公式,获得的CeF3衰减常数值与国外研究同行其它测量方法得到的结果基本一致。     

Study on Coordination of Diamoxime Ligand with Cu~(2+)

<正>Amidoxime-based adsorption materials are now widely studied for uranium extraction from seawater.Considering the diversity of the seawater environment,the selectivity and efficiency of the adsorption material should be improved for uranium studies of the coordination of simple amidoxime ligand with uranium and other metal ions in seawater,which can provide reference for the development of adsorbents.The coordination of succinamidedioxime with uranium was studied.This work mainly discussed the coordination of succinamidedioxime with divalent copper ions under seawater conditions.     

External micro-PIXE analysis of Nd~(3+) accumulation in Euglena gracilis

External micro-PIXE measurements were done to investigate the accumulation of Nd~(3+)on green algae species euglena gracilis.According to the Nd distribution patterns in the gracilis cells,the biosorption of Nd~(3+)to the cell's compartments can be observed.Comparing elemental mappings of the cell treated with different doses of the 1 mg/mL Nd~(3+)solution,the Nd uptake of euglena gracilis cells do no relate with the doses.From distributions of Ca and Mg,it is found that the Ca is complementary to Nd partly,and the Nd and Mg distributions are alike to each other,showing that Nd may be mainly in the chlorophyll molecules.The biochemistry related is discussed.     

Phase study in the Na-Sr-U-O system: Characterization of new phase

In continuation with the earlier work for phase studies of Rb-Sr-U-O and Cs-Sr-U-O systems, the subsolidus phase relations in Na-Sr-U-O quaternary system were determined at 850 °C in air atmosphere. A novel quaternary phase Na₈Sr₂U₆O₂₄ in the Na-Sr-U-O system was synthesized by heating the respective oxides at 850 °C in air. XRD data of Na₈Sr₂U₆O₂₄ was indexed on a cubic system with lattice parameter a = 0.8326 nm and was found isostructural with K₈Sr₂U₆O₂₄ and Rb₈Sr₂U₆O₂₄. A pseudo-ternary phase diagram of Na₂O-SrO-UO₃ was drawn using the new quaternary compound and various phase fields were established by X-ray powder diffraction analysis. The structure of Na₈Sr₂U₆O₂₄ was derived from the powder data and structural parameters were refined by the Rietveld profile method.     

氘团簇离子(d3+)固体与相互作用过程中的团簇行为研究

讨论了由三个氘原子组成的氘团簇离子(d3+)束与独立氘离子束在轰击固体靶时,在原子过程和D-D核聚变过程中体现出的差别.对氘团簇与固体靶相互作用的机理进行了分析.     

用于台北微中子震荡(TEXONO)实验的液体闪烁液的性能研究

配制了20多种不同比分的液体闪烁液以及加入不同比分的^10B的样品,对这些样品的光产生量、n-γ分辨能力等性能进行了测试,并与标准的NE213液体闪烁液的相关性能进行了比较。     

氘团簇离子（d^＋3）与固体相互作用过程中的团簇行为研究

讨论了由三个氘原子组成的氘团簇离子束与独立氘离子束在轰击固体靶时,在原子过程呼Ｄ－Ｄ核聚变过程中体现出的差别。对氘团簇与固体靶相互作用的机理进行了分析。     

[2′,6′-~3H]除草醚和[2′,6′-~3H]草枯醚的合成

用合成法制备了[2’,6’-~3H]除草醚和[2’,6’-~3H]草枯醚。以间溴氯苯(Ⅰ)为起始原料,经催化卤-氚取代反应制得[3,5-~3H]氯苯(Ⅱ);然后用硝酸-浓硫酸的混合物硝化(Ⅱ)得[3,5-~3H]对氯硝基苯(Ⅲ);最后使(Ⅲ)分别与2,4-二氯苯酚或2,4,6-三氯苯酚起缩合反应生成[2’,6’-~3H]除草醚(Ⅳ)和[2’,6’-~3H]草枯醚(Ⅴ),比活度分别为1.16TBq/mol和1.89TBq/mol,放化纯度均大于95％。     

Carlo DTS: A Monte Carlo code for the dual thin scintillator neutron detector

A Monte Carlo code called CARLO DTS, developed for the efficiency and proton recoil spectra calculation of the Dual Thin Scintillator (DTS) neutron detector is described. The code CARLO DTS covers the neutron energy range between 1 and 20 MeV. The cross sections and angular distributions were taken from the ENDF/B-V data file for the nuclear reactions involved: H(n.n)H, C(n,n)C and inelastic scattering, (n,), (n,n′)3 reactions on carbon-12. The theoretical calculations are compared to experimental results at two neutron energies, namely:2.446 and 14.04 MeV, obtained by means of the Time Correlated Associated Particle Technique.     

N-乙酰半胱氨酸对碳离子照射小鼠急性损伤的保护效应

探讨了N-乙酰半胱氨酸(N-acetylcysteine,NAC)对12C6+离子照射小鼠损伤的保护效应及可能的作用机制.预先给予昆明小鼠NAC(200mg/kg),后进行12C6+离子束4Gy的单次全身照射.照射后2h处死小鼠,取肝、肺组织,用化学法检测组织中超氧化物岐化酶(Superoxide dismutase,SOD)的活性,谷胱甘肽(Glutathione,GSH)含量及脂质过氧化产物丙二醛(Malondialdehydc,MDA)水平;用碱性单细胞凝胶电泳法检测DNA单链断裂;用流式细胞术检测组织细胞凋亡率.与照射对照组相比,提前给予NAC可极显著地减轻12C6+离子导致的肝、肺组织中DNA断裂(p<0.001)和细胞凋亡(p<0.001),并显著地提高组织中GSH的含量;NAC还明显地抑制了肺组织中碳离子辐照所致的MDA水平增高(p<0.01)并显著地诱导了组织中SOD活性的升高(p<0.01).提示NAC可通过抵御组织内的氧化作用,合成、补充GSH的含量,阻止DNA链的断裂和细胞的凋亡,实现对碳离子辐照损伤的保护效应.     

Cl~-和Cu~(2+)对国产690合金应力腐蚀性能的影响

采用慢应变速率拉伸(SSRT)的方法,研究国产690合金分别在316℃含100 mg/L Cl-、1000 mg/L Cu2+以及100 mg/L Cl-与1000 mg/L Cu2+混合溶液中的应力腐蚀行为。通过激光共聚焦显微镜和扫描电镜观察断裂后试样的表面、断口以及纵剖面的微观形貌。结果表明:国产690合金在同时含Cl-与Cu2+的溶液中具有较高的应力腐蚀敏感性;断裂试样表面出现了大量的腐蚀坑,断口呈明显的脆性断裂特征,且在表面蚀坑的底部发现了沿晶应力腐蚀裂纹的萌生。由此证明Cl-与Cu2+对国产690合金应力腐蚀的协同作用,并初步探讨了其作用机理。