Experimental and calculated effectiveness of a radiochromic dye film to stopping 21 MeV 7Li and 64 MeV 16O ions

Relative radiation effectiveness, RE, of 21 MeV ⁷Li and 64 MeV ¹⁶O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a δ-ray theory for heavy charged particles developed by Katz et al. The experiment was designed to test calculations particularly in the Bragg-peak region of the slowing down particles where significant deviation between theory and experiment was found. Fitting of the characteristic D₃₇ dose and the size of the radiation sensitive element in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the δ-ray spectrum and the slowing down spectrum of electrons from low-LET radiation, and partly from approximations in the calculated distribution of energy deposition of the δ-rays.     

The complex momentum representation approach and its application to low-lying resonances in 17O and 29,31F

Approaches for predicting low-lying resonances, uniformly treating bound, and resonant levels have been a long-standing goal in nuclear theory. Accordingly, we explored the viability of the complex momentum representation(CMR) approach coupled with new potentials. We focus on predicting the energy of the low-lying 2p_3∕2 resonance in 17 O, which is critical for s-process nucleosynthesis and missing in previous theoretical research. Using a Woods-Saxon potential based on the KoningDelar...     

级联生产稳定同位素18O的模拟优化研究

本工作利用已有的四塔级联设计方案,通过采用均匀设计方法对操作参数进行优化,并利用二项式逐步回归求取模型方程,同时利用遗传算法对模型进行了优化设计,综合分析了不同进料量及级间流量对¹⁸O产品丰度的影响,得到产品¹⁸O的丰度与进料量及级间流量和热量消耗与进料量及级间流量的数学关系式,并得出进料量与级间流量的单因素响应图。本研究采用的模拟优化方法可应用到¹⁸O的产业化生产及推广至传统精馏过程的优化设计中。     

Gamma-ray emission probabilities of the fission products 144Ce144Pr, 106Rh, 95Zr

The fission products ¹⁴⁴Ce¹⁴⁴Pr, ¹⁰⁶Rh and ⁹⁵Zr play an important role in the burn-up determination of fuel elements by means of γ-ray spectrometry. One of the crucial quantities in this field is the absolute γ-ray emission probability (intensity) for which values available in literature have not the desirable accuracy of 1–2%.By using Ge(Li)-spectrometers of known efficiency and sources calibrated by 4πβ-γ-coincidence methods, we determined absolute γ-ray emission probabilities of ¹⁴⁴Ce¹⁴⁴Pr, ¹⁰⁶Rh and ⁹⁵Zr with an uncertainty of ±1% for the main γ-rays.     

18O离子辐照过的天然铀中镤的分离和镤同位素新γ射线的观察

用液-液萃取法对     

Unbound 28O,the heaviest oxygen isotope observed:a cutting-edge probe for testing nuclear models

<正>The beyond-dripline oxygen isotopes ^27,28O were recently observed at RIKEN, and were found to be unbound decaying into ²⁴O by emitting neutrons. The unbound feature of the heaviest oxygen isotope, ²⁸O, provides an excellent test for stateof-the-art nuclear models.The atomic nucleus is a self-organized quantum manybody system comprising specific numbers of protons Z and neutrons N. The nuclear force, which binds protons and neutrons together, favors equal...     

海水中放射性核素238U、232Th、600Co、137Cs浓集实验

采用广东省环境辐射监测中心编制的操作规程《海水中γ核素浓集方法实施细则》分析了环境海水样品的γ放射性核素238U、232Th、60Co、137Cs,该方法的238U、232Th、60Co、137Cs的回收率分别为82.5%、79.3%、80.3%、91.3%;制样放置约90 d后测量238U的数据更准确。     

水平衡法与高温转化法在矿泉水氢氧稳定同位素测定中的应用

为了鉴别不同品牌矿泉水标注水源地信息真伪,对11种不同品牌饮用水的氢氧稳定同位素(δD和δ¹⁸O)进行测定。结果表明,水平衡法(GasBench-IRMS)和高温转化法(TC/EA-IRMS)的测定结果一致性较好,两种方法测定6种不同饮用水的δD和δ¹⁸O的平均差异分别为(0.6±1.59)‰和(0.02±0.13)‰。水平衡法需要较长的制备和测定时间,但δD和δ¹⁸O的测定精度明显优于高温转化法。11种饮用水δD和δ¹⁸O变化范围较大,其δD和δ¹⁸O受不同品牌饮用水的水源地降水影响形成明显的地域性。虽然无法区分矿泉水是否由其他类别饮用水伪造,但δD和δ¹⁸O可以为特定区域(如高海拔与沿海地区)以及产地相近的矿泉水水源地鉴别提供依据。     

K-shell X-ray cross-section ratios for 1H, 4He and 6Li projectiles on targets from fluorine to titanium

Experimental K X-ray emission ratios have been measured for nine elements ranging from F to Ti (9 ? Z₂ ? 22) using ¹H⁺, and ⁶Li⁺ projectiles. The experimental ratios are in fair agreement with theoretical predictions for the velocity range studied, $\text{?}{}_{\mathrm{k}}\text{\$}\text{?}\text{1}$.     

Neutron elastic scattering angular distribution in the resolved and unresolved resonance regions

We derive a simple relationship between observed total cross sections and elastic scattering angular distributions for neutron-induced reactions in the fast energy range by combining resonance theory and the optical model (OM). This relationship enables us to estimate the anisotropy in the scattering angular distribution when experimental total cross-section data are available. We apply this method to the angular distributions of ⁵⁸Ni and ⁵⁶Fe and compare with the evaluated values which are based on the experimental data. We also explore the method with ⁹⁰Zr for which the multi-level Breit-Wigner resonance parameters are given.     

Sr树脂在气溶胶~(210)Pb、~(210)Bi和~(210)Po联合分析中的初步应用

气溶胶中~(210)Pb、~(210)Bi和~(210)Po的活度浓度处于不平衡状态,本工作对3种核素联合分析进行了方法设计,并采用标准溶液对方法进行了验证。方法验证了Sr树脂对Pb-Bi-Po的分离。依据三种核素的回收率~(210)Bi(约97%)~(210)Po(约93%)~(210)Pb(约89%)、PbSO_4中~(210)Bi的生长曲线及BiOCl的衰变曲线,可以确定Sr树脂对3种核素的分离效果较好。Sr树脂在气溶胶~(210)Pb、~(210)Bi和~(210)Po中的联合分析应用研究,可以应用于探究气溶胶中Pb-Bi-Po不平衡现象,为气溶胶分析提供技术方法。     

氟盐冷却高温堆主冷却剂系统16N源项分析

基于SCALE6.1程序包中的三维蒙特卡罗输运程序KENO-Ⅵ对氟盐冷却高温堆（FHR）堆芯中子能谱进行计算,利用Mathematica程序建立了¹⁶N源项在主冷却剂系统内的流动模型,对FHR的主冷却剂系统¹⁶N源项进行定量分析,对不同流速情况下主冷却剂系统不同区域¹⁶N源强分布进行研究。结果表明：当冷却剂体积流量大于4.15×10² cm³•s^-1、小于4.15×10⁶ cm³•s^-1时,流动效应对主冷却剂系统内¹⁶N源项浓度分布影响显著,在FHR的设计基准流量（4.15×10⁴ cm³•s^-1）情况下,堆芯中¹⁶N源项占总¹⁶N源项的76.98%,上腔室为18.89%,其余区域放射性活度占¹⁶N总量的4.13%。所建立分析方法及结论可为FHR的工程设计、辐射防护设计及源项的精确分析等提供参考。     

有临床应用意义的^188W／^188Re发生器的研制

对^188W/^188Re发生器的吸附条件及装柱工艺等进行了研究,确定了最佳的吸附条件及吸附容量等重要参数,制备了以酸性氧化铝为吸附剂的医用^188W/^188Re发生器（7．40GBq),可用生理盐水淋洗得到^188Re.^188Re的淋洗效率在3个月之内大于70％,^188W的漏穿率小于10^-4%,核纯度和放射化学纯度均大于99％。     

Dependence of Quasi-Particle Alignment on Proton Number in N=44 Isotones 82Sr,83Y,84Zr and 85Nb

The g-factors of Ground Rotational Band states of N=44 isotones 82Sr, 83Y, 84Zr and 85Nb have been measured by the transient-magnetic-field ion implantation perturbed angular distribution (TMF-IMPAD) method. The measured g-factors of 82Sr increase with the increase of spin I, indicating a proton alignment only. Positive peaks appear in the variation of g-factors with spin for 83Y and 84Zr at spin 21/2+ and 10+ respectively, indicating a proton alignment followed by a neutron alignment. A negative peak occurs for 85Nb at the spin25/2+ , indicating a neutron alignment followed by a proton alignment.     

B3Y-FETAL effective interaction in the folding analysis of elastic scattering of 16O+16O

In this paper,a new M3Y-type effective nucleon-nucleon interaction,derived based on the lowest order constrained variational approach(LOCV)and termed B3Y-Fetal,...     

山西、河南三地土壤样品中239+240Pu、137Cs分析

采用电感耦合等离子体质谱(ICP-MS)分析了中国中部地区三地(山西长治、河南濮阳和商丘)钻芯(0～30 cm)土壤样品中的239 240 Pu活度浓度和240Pu/239pu同位素比值,并对239 240 Pu和137Cs在土壤中的深度分布进行了研究.结果表明,三地表层土壤(0～2 cm)中239+ 240pu活度浓度为0.078 ～0.122mBq/g,137Cs为1.56 ～2.91 mBq/g,且浓度整体随深度增加而降低;240Pu/239 Pu原子比的平均值为0.188±0.016(全球沉降平均值为0.180±0.014),137Cs/239240Pu活度比值为34.61 ±5.91(1998年7月,全球沉降平均值为34±4).三地土壤中放射性核素137 Cs、239+240Pu浓度及钚同位素比值均与全球沉降值相当,说明其来源可能属于全球沉降.     

The Applications and Fabrication Methods of 90Sr/90Y Sources

The applications of ⁹⁰Sr/⁹⁰Y sources were reviewed on clinical medicine, thickness gauge, continuous energy supply for science and industry, reference source for contamination calibration. The application of each source proposes certain requirement for the source properties, and that could be realized by some corresponding preparation method. Different⁹⁰Sr/⁹⁰Y source preparation methods for each application were introduced, and the characteristics of them were contrasted.     

用聚酰胺树脂从~(99)Mo中提取~(99)Tc~m

固相分离材料是色层法从低比活度~(99)Mo料液中分离医用同位素~(99)Tc~m的关键。采用静态吸附和动态吸附淋洗实验,研究了聚酰胺树脂从~(99)Mo中吸附分离其衰变子体~(99)Tc~m的工艺,评价了其性能。结果表明:在NaOH浓度为3mol/L的钼酸钠溶液中,聚酰胺树脂能够在10s内选择性地吸附高锝酸根离子,并具有3.85mg/g的饱和吸附容量。2.0g装柱量的聚酰胺色层柱的漏穿体积约为70 mL,可用25 mL 3 mol/L NaOH溶液洗涤柱上残留的钼酸根离子,最后20mL水即可将吸附在聚酰胺色层柱上的锝淋洗下来。本研究为开发基于色层法的全自动~(99)Mo/~(99)Tc~m发生器装置提供了一种新型钼锝固相分离材料,其提取锝的淋洗效率为98%,洗脱液中钼的残留为0.6mg/L。     

含^60Co和^152Eu放射性废液的水泥固化配方研究

针对含60Co3.8×105Bq/L、152Eu6.67×105Bq/L、总放射性活度为2×107Bq的放射性废液进行了水泥固化配方及工艺试验研究。结果表明水泥浆流动度和初凝时间随水灰比增大而增大,而固化体的抗压强度则随其增大而降低。优选配方的水泥固化体各种性能均满足中低放废液固化体性能要求水泥浆流动度≥130mm;水泥固化体28d抗压强度＞7MPa;42d浸出率60Co为1.84×10-4cm/d、152Eu为2.76×10-5cm/d（剂灰比0.15）,60Co为5.47×10-4cm/d、152Eu为1.55×10-4cm/d（无添加剂）;总β的累积浸出分数（42d）分别为1.7×10-2cm（剂灰比0.15）和3.5×10-2cm（无添加剂）。     

北京地区大气中7Be、137Cs和131I活度浓度分布规律初步研究

介绍了全面禁止核试验条约（CTBT）国际监测系统（IMS）北京核素台站和北京放射性核素实验室的大气气溶胶取样和测量过程;对核素台站和放射性核素实验室的大气气溶胶的长期监测数据进行了统计分析,得到了⁷Be、¹³⁷Cs和¹³¹I活度浓度的分布特点和规律,为深入研究大气中相关放射性核素浓度分布规律奠定了基础。