中能质子入射散裂反应研究

采用改进的量子分子动力学模型（ImQMD05）加统计衰变模型（SDM），研究了中能质子入射散裂反应。     

QMD SDM方法计算中能核裂变数据(英文)

采用量子分子动力学(QMD)和统计衰变模型(SDM)分析计算了中能中子入射锕系核素引起裂变的瞬发裂变中子数和裂变中子谱。同时给出了用于本计算的一个简单的半经验的能级密度参数公式。这样,仅需要很少的输入参数便可得到合理的结果。     

中能质子入射的裂变产物质量分布计算

采用量子分子动力学和统计衰变模型以及半经验的多模裂变模型等方法,分别对由200 MeV左右质子入射锕系和非锕系重核引起裂变的裂变产物质量分布进行了计算,通过拟合190 MeV p ~(208)Pb和170 MeV p ~(238)U的裂变产物质量分布的实验数据,对锕系和非锕系重核分别给出了用于多模裂变模型的两组拟合参数。并采用这两组参数计算了190 MeV p ~(197)Au,184 MeV p ~(209)Bi和190 MeV p ~(232)Th的裂变产物质量分布,与实验值比较可以看出,采用这个方法能够得到符合实验数据的计算值,这两组参数也可以推广用于处于这一能区的重核裂变产物质量分布的描述。     

800MeV质子入射^160、^27Al、^56Fe、^112Cd、^184W与^208Pb靶散裂反应机制

采用改进的量子分子动力学模型（ImQMD05）加统计衰变模型（SDM）来研究800MeV质子入射的散裂反应。采用不同的平均场，研究有效相互作用对散裂反应机制的影响，并给出工程应用上关心的出射中子的双微分截面。     

利用LR 115 2B研究7.4GeV质子束轰击铅靶的散裂中子源外表面中子分布

利用LR 115 2B探测器研究了8cm× 2 0cm的铅靶在 7.4GeV质子的轰击下 ,散裂中子在实验装置外表面的分布 ,对实验结果进行了模拟解析 ,同时利用中子活化法验证了LR 115 2B探测结果及理论模拟结果利用LR 115 2B探测器研究了8cm× 2 0cm的铅靶在 7.4GeV质子的轰击下 ,散裂中子在实验装置外表面的分布 ,对实验结果进行了模拟解析 ,同时利用中子活化法验证了LR 115 2B探测结果及理论模拟结果     

质子入射能量Ep≤100 MeV的(p,n)反应激发函数半经验计算方法

基于核反应的蒸发模型和预平衡激于模型，在靶核质量数为30≤A≤140、质子入射能量Ep≤100MeV范围内，对上述模型理论进行了简化，得到了计算(p，n)反应的激发函数的半经验公式。计算结果与已有实验数据的核索符合很好，同时得到了有关参数的系统学公式。     

一种新中能质子加速结构的研究(英文)

提出一种新的环耦合漂移管结构,它用于加速β在0.2～0.5的质子。这种结构易于制造、加工公差要求低、体积小、可得到较大的耦合系数。采用这种结构,将有利于未来加速器的设计。     

~(235)U裂变碎片在PIN探测器中沉积能量的实验研究

利用中子与235U发生裂变反应的截面在裂变中子能区基本不变这一特点,可设计研制裂变靶室探测系统,该系统中子能量响应较平坦,在脉冲中子总数测量中有广阔的应用前景。利用K-400加速器稳态DT中子源,实验标定了235U裂变碎片在PIN探测器中的平均沉积能量,并与理论计算结果进行了比较。裂变靶室系统探测效率可通过数值计算准确给出,与平均沉积能量实验测量值相结合,可得到准确的中子灵敏度数据,进而获得裂变靶室探测系统中子能量响应曲线。     

10 能量相关的动力学熔合势垒

用改进的量子分子动力学模型研究了与入射能量相关的重离子动力学熔合势垒。在库仑势垒附近，随着入射能的降低可以观察到动力学势垒的最低值，这个最低动力学势垒与绝热势垒非常接近；另一方面，动力学势垒随着入射能的增加而升高，当入射能增加到一定程度，动力学势垒变化很慢，越来越接近于静态势垒（非绝热势垒）。基于动力学势垒的研究，对于重离子熔合反应的额外推动extra-push给出了一个微观理解。     

利用MSDM分析1GeVP+208Pb散裂反应产物

利用Ignatyuk能级密度公式代替多步动力学模型(MSI)M)中的费米气体能级密度公式，并考虑壳效应对能级密度的影响，以改进其对质子引起散裂产物的形成截面研究。对1GeV p ^208Pb散裂产物的电荷、质量分布以及产物核同位素形成截面的计算结果好于利用费米气体能级密度的MSDM计算结果。利用该程序研究获得的散裂产物中的裂变核、散裂核以及二者之间的产物核的同位素形成截面和实验数据符合较好，并好于LAHET、YIELDX以及INCL4 KHSv3p模型计算结果。     

Evaluation of Neutron- and Proton-induced Nuclear Data on 27Al up to 2 GeV

We have evaluated neutron and proton nuclear data of ²⁷ Al for energies up to 2 GeV. The best set of optical model parameters were obtained from 20MeV for neutrons and from reaction threshold for protons up to 250 MeV with the phenomenological non-relativistic potential forms incorporating effects of the dispersion relationship and results of the Dirac phenomenology. The transmission coefficients for neutrons and protons derived from the optical models were fed into the GNASH code system to calculate angle-energy correlated emission spectra for light ejectiles and gamma rays. For energies between 250 MeV and 2 GeV, the total, reaction and elastic scattering cross sections were evaluated by an empirical fit and recent systematics. Emitted nucleon and pion spectra were estimated by use of QMD+SDM (Quantum Molecular Dynamics+Statistical Decay Model).     

可用一台ADS验证装置的150 MeV固态金属散裂中子靶的性质研究

对可以用于中国“加速器驱动洁净核能系统”的入射质子能量为150MeV,束流为3 mA的固态金属靶进行了研究。采用锥型几何结构作为靶的结构,材料选择钨,靶厚度为3 mm,对“靶-束窗”一体化结构进行了研究。研究了泄露中子产额和中子产额,泄露中子的能谱分布和空间分布,散裂碎片的分布以及能量沉积和辐射损伤。     

Maruhn–Greiner Maximum of Uranium Fission for Confirmation of Low Energy Nuclear Reactions LENR via a Compound Nucleus with Double Magic Numbers

One of the most convincing facts about LENR due to deuterons of very high concentration in host metals as palladium is the measurement of the large scale minimum of the reaction probability depending on the nucleon number A of generated elements at A = 153 where a local maximum was measured. This is similar to the fission of uranium at A = 119 where the local maximum follows from the Maruhn–Greiner theory if the splitting nuclei are excited to about MeV energy. The LENR generated elements can be documented any time after the reaction by SIMS or K-shell X-ray excitation to show the very unique distribution with the local maximum. An explanation is based on the strong Debye screening of the Maxwellian deuterons within the degenerate rigid electron background especially within the swimming electron layer at the metal surface or at interfaces. The deuterons behave like neutrals at distances of about 2 picometers. They may form clusters due to soft attraction in the range above thermal energy. Clusters of 10 pm diameter may react over long time probabilities (megaseconds) with Pd nuclei leading to a double magic number compound nucleus which splits like in fission to the A = 153 element distribution. An erratum to this article can be found at     

~6Li+~(208)Pb光学势灵敏半径的能量相依性

光学势灵敏区域的确定是研究光学势性质的先决要素。本工作利用扰动法,抽取并研究了弱束缚体系~6Li+~(208)Pb光学势灵敏区域的能量相依性。结果表明,该体系光学势实部和虚部的灵敏区域均呈现多峰结构。内部的灵敏区域对应体系库仑势垒的穿透过程,其位置基本不随能量的变化而改变;而外部的灵敏区域则对应体系的表面相互作用过程,并且存在强烈的能量相依性。采用新的灵敏区域重新检测了~6Li+~(208)Pb光学势的性质,结果表明在新的灵敏区域内,~6Li+~(208)Pb光学势虚部表现出传统的阈异常现象,而并非之前所观察到的破裂阈异常现象。     

Fission Product Model for BWR Analysis with Improved Accuracy in High Burnup

A new fission product (FP) chain model has been studied to be used in a BWR lattice calculation. In attempting to establish the model, two requirements, i.e. the accuracy in predicting burnup reactivity and the easiness in practical application, are simultaneously considered. The resultant FP model consists of 81 explicit FP nuclides and two lumped pseudo nuclides having the absorption cross sections independent of burnup history and fuel composition. For the verification, extensive numerical tests covering over a wide range of operational conditions and fuel compositions have been carried out. The results indicate that the estimated errors in burnup reactivity are within 0.1Δk for exposures up to 100GWd/t. It is concluded that the present model can offer a high degree of accuracy for FP representation in BWR lattice calculation.     

Development of Three-Dimensional Numerical Model for 222Rn and Its Decay Products Coupled with a Mesoscale Meteorological Model II. Numerical Analysis on the Increase in Gamma Dose Rate Observed in the Coastal Area of Fukushima Prefecture

A three-dimensional Eulerian numerical model for ²²²Rn and its decay products coupled with a mesoscale meteorological model, MM5-TMNR, is applied to investigate the mechanism of the naturally induced increase in gamma dose rate observed at the coastal area of Fukushima prefecture in October 2002. The results obtained by MM5-TMNR are verified by comparisons with observed wind, precipitation and gamma dose rate to be adequate for examining the mechanism. The unusual increase in gamma dose rate is observed by the combination of the synoptic-scale (about 2000 to 5000 km horizontally) transport of natural radionuclides due to the inflow of cold air mass from the Asian Continent and the meso-_-scale (about 20 to 200 km horizontally) precipitation process within the coastal area of Fukushima prefecture. The contribution rate of natural radionuclides from the Asian Continent to the increase in gamma dose rateis estimated to be more than 60%.     

Cross sections of deuteron induced reactions on Cr up to 50 MeV: Experiments and comparison with theoretical codes

Activation of Cr-containing components around high energy deuteron accelerator can pose radioprotection problems for maintenance personnel. In a stacked foil irradiation, followed by high resolution gamma spectroscopy the cross sections for production of ^46,47,48Sc, ⁵¹Cr, ^52,54Mn and ⁴⁸V were measured up to 50 MeV resulting in first systematic assessment above 15 MeV. Reduced uncertainty is obtained by simultaneous remeasurement of the Al(d,x)²⁴Na or Ti(d,x)⁴⁸V monitor reactions over the whole energy range. A comparison with experimental literature values and results from updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2010 on-line library) is discussed.