共查询到20条相似文献,搜索用时 21 毫秒
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为了将NaI探测器更好地应用到轫致辐射谱测量工作中,对一套NaI探测器做了研究:利用~(137)Cs,~(60)Co等同位素γ源,结合蒙特卡罗方法,得到全能峰效率的模拟值与实验测量值符合得较好;利用蒙特卡罗N粒子编码模拟NaI对不同能量光子的响应,得到了该探测器对光子的能量响应,并将获得的能量响应用于轫致辐射的解谱工作,解谱结果与原始谱符合得很好;将该探测器应用到强流电子束打靶轫致辐射测量实验中,对轫致辐射在NaI探测器中的响应做了初步测量. 相似文献
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A.M. Reda 《Radiation measurements》2011,46(10):1187-1193
Shielding for a D–T sealed neutron generator has been designed using the MCNP5 Monte Carlo radiation transport code. The neutron generator will be used in field for the detection of explosives, landmines, drugs and other ‘threat’ materials. The optimization of the detection of buried objects was started by studying the signal-to-noise ratio for different geometric conditions. 相似文献
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基于自主研制的三维中子-光子耦合输运蒙特卡罗通用程序JMCT(J Monte Carlo Transport Code),采用连续点截面,对国际基准屏蔽VENUS-III模型开展精细建模和中子输运临界及屏蔽计算.临界计算得到系统keff、重要区域的通量及能谱.结果表明,JMCT和MCNP程序的重要区域体通量计数吻合较好,偏差均在1%以内.深穿透屏蔽计算采用外源模式,点探测器计数,JMCT计算值与实验测量值偏差在15%以内,满足屏蔽设计对误差的要求.初步验证了JMCT程序临界及屏蔽计算的可用性. 相似文献
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热辐射与物质相互作用及辐射光子在物质中的传输是惯性约束聚变研究中的重要课题. 介绍了基于隐式蒙特卡罗方法的辐射输运方程,在该方程的积分-微分形式基础上,推导了利于蒙特卡罗方法模拟的等价的积分输运方程;基于积分方程设计数值模拟流程,编写三维蒙特卡罗数值模拟程序;针对热辐射输运典型问题及benchmark问题开展了数值实验,计算结果验证了方法的适应性及程序的正确性.
关键词:
热辐射
惯性约束聚变
输运方程
隐式蒙特卡罗 相似文献
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利用编制的快中子照相数值模拟程序(FNRSC)模拟计算了入射中子能量为14 MeV时,厚度5—300 mm闪烁体内次级中子对快中子图像质量的影响,结果表明闪烁体厚度d<50mm时,次级中子对图像的影响强烈依赖于闪烁体厚度,而当d>50 mm时,次级中子对图像的影响趋于饱和.将文献中利用蒙特卡罗中子-光子输运程序(MCNP)计算的次级中子对图像影响和文中计算结果进行了对比,给出了二者存在差异的主要原因:次级中子分布对入射中子空间分布的强烈依赖性;能量沉积和荧光输出这两种计算方法对
关键词:
14 MeV中子
快中子照相
次级中子
Monte Carlo模拟 相似文献
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Jorge A. Díaz-Díaz Rigoberto Oros-Pantoja Liliana Aranda Lara Patricia Vieyra-Reyes 《辐射效应与固体损伤》2018,173(7-8):567-577
Radiodiagnosis and radiation treatment, in each of their areas such as imaging, radiotherapy and nuclear medicine, require precise calculations about the energy deposited and scattering of the ionizing radiation used. In healthcare applications, it is required to know the penetration and amount of energy deposited in the biological tissue irradiated by ionizing photons; these parameters are function of the photon interaction processes with matter, which can be analyzed experimentally or by Monte Carlo simulation. Purpose: The aim of this work was to develop a new Monte Carlo code for ionizing photon transport in water with the track structure technique, that allows to discriminate primary and secondary photons, and to determine the energy deposited, interaction coordinates, path length and time of flight (TOF) inside of scatter volume. Methods: C++ programming language was used. In the Compton scattering, the polar angle was sampled by methods: Kahn and EGS. Water spheres centered at the origin with different radius were used, where the isotropic point source was placed at (0, 0, 0) for different energies to compute the energy lost by photons and TOF inside spherical volume. Results: It was determined that the best sampling method for the polar angle generation in each Compton interaction was the EGS method. Energy deposited in target region filled with water was compared with MCNPX 2.6 and others’ results from literature. Mean TOF and pathlength inside region of interest was obtained for 4 radii and 5 energies. Conclusions: Quantities computed with the new code are, according to reported data, and so, the new code is reliable for photon transport in water using the track structure method; this will allow the new code to become a useful tool in the areas of radiology and radiation dosimetry. Also, TOF inside scatter volume was reported. 相似文献
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To investigate carbon‐based material erosion and ensuing eroded carbon species density distribution, a Particle‐In‐Cell Monte Carlo collision code plus a plasma‐surface interaction code were combined with a Monte Carlo impurity transport code ITCD. It is found that a “density hill” forms at a distance of 3‐4 mm from divertor target plate under certain circumstances: high plasma temperature, small incident angle and strength of the magnetic field. By means of the study with the combined code on several scenarios with different plasma temperatures, the incident angles and strengths of the magnetic field, the simulation results reveal that they have a significant influence on the chemical erosion of carbon‐based material and the spatial distribution of eroded carbon species density above divertor target plate: the eroded carbon species density is smaller at a lower plasma temperature; the scenario with smaller incident angle and greater strength of the magnetic field can reduce the chemical erosion of carbon‐based material and the eroded carbon species density above divertor target plate evidently (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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基于临床实例的影响蒙特卡罗程序MCNP计算精度和速度的若干参数模拟研究 总被引:1,自引:0,他引:1
蒙特卡罗方法是目前最精确的剂量计算方法,但其较长的模拟时间阻碍了它在临床治疗中的应用。基于蒙特卡罗程序MCNP4c,针对一临床头部病例,探讨了记数方法、电子和光子截断能、光子产生次级电子参数ENUM对计算速度和精度的影响,给出了在保证一定精度前提下的最佳计算模式,以获得计算速度的有效提升。Monte its long simulation and photons, and investigated based Carlo method is regarded as the most accurate method for dose calculation at present, whereas time hinders its clinic application. The effects of the tally method, the cut-off energy of electrons the secondary electron number parameter ENUM on precision and speed of MCNP4c have been on a clinical case to seek for a relatively optimum calculation mode. 相似文献
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采用蒙特卡罗程序MCNP计算了西安脉冲堆中子代时间。使用MCNP程序模拟了反应堆瞬发中子通量密度衰减,基于忽略缓发中子项的点堆动力学方程计算出中子代时间。在微次临界下,研究了次临界度、源的分布、计数区域等对西安脉冲堆中子代时间计算结果的影响。计算分析表明:采用瞬发中子密度衰减法计算中子代时间时,微次临界度、源分布、计数区域等对计算结果影响都很小;误差产生的主要原因是忽略缓发中子项的点堆动力学方程并不能较好地反应瞬发中子通量密度的衰减规律。 相似文献
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真空磁绝缘传输线建立磁绝缘状态的初始阶段,损失电子轰击阳极,发生轫致辐射。针对自限制流同轴圆筒模型,通过粒子模拟获得了损失前沿在能量传输方向的推进速度、电子到达阳极时的能谱和角分布情况,在此基础上采用蒙特卡罗方法模拟得到了轫致辐射所产生的X射线能谱。数值计算结果表明:电磁波损失前沿在能量传输方向的推进速度小于光速;损失前沿电子密度稳定。在自限制流磁绝缘传输线中,损失电子处在较宽的能量范围内,其电子偏移角度较小。建立了对应于同轴圆筒真空磁绝缘传输线的电子/光子输运模型,获得了损失电子轰击阳极产生的X射线能谱。 相似文献
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This paper shows the calculations of radioactivity and afterheat
in the components of the China Spallation Neutron Source (CSNS) target
station, with the Monte Carlo codes LAHET, MCNP4C and the multigroup
code CINDER'90. These calculations provide essential data for the
detailed design and maintenance of the CSNS target station. 相似文献
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特征γ谱蒙特卡罗模拟方法的改进 总被引:5,自引:1,他引:4
针对中子-γ耦合输运问题,采用蒙特卡罗统计估计和期望值技巧,分别计算了被探测物的总能谱、时间谱和每个元素的特征γ谱,并与MCNP程序结果进行了对比. 相似文献
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使用JMCT (J Monte Carlo Transport Code)对来自MIT的全堆芯pin-by-pin精细建模的国际基准模型BEAVRS的热零功率(HZP)状态进行了模拟计算, 并与测试数据进行了对比和分析. 比较的物理量包括临界本征值、控制棒价值、反应性温度系数、轴向积分的全堆探测器测量值和不同位置四个组件轴向相对功率密度分布. HZP状态下不同控制棒位置插入和硼浓度的临界本征值计算, JMCT结果与理论值1.000 的误差小于0.2%, 控制棒价值计算结果与测量值符合. JMCT对轴向积分的探测器径向相对功率分布和四个组件的轴向归一化的探测器的计算结果与测量值进行了比较和分析, 计算结果与测量值一致, 同时清晰地展示了模型增加格架后, 轴向功率曲线在相应位置出现下凹的现象. 此外, JMCT给出了轴向积分的组件径向相对功率密度分布和轴向相对功率最大处(Z轴位置)的pin径向相对功率密度分布, 并与国际知名程序MC21结果进行了对比, 两个图像都符合得非常好. 随着计算机与并行计算的高速发展, 蒙特卡罗程序开始从传统的反应堆校验工具向反应堆设计工具转变. 相似文献