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Dose rate profile inside the spent fuel storage pool in case of full capacity storage 满容量贮存情况下乏燃料贮存池内的剂量率分布图
Pub Date : 2020-08-10 DOI: 10.15415/jnp.2020.81002
Amr Abdelhady
This study aims to evaluate the radiation dose rate distribution inside temporary spent fuel open-pool storage. The storage pool is connected to the main pool via transfer channel to facilitate transporting the spent fuel under water that avoiding radiation dose rising in the working area in the reactor. The storage pool was prepared to store 800 spent fuel elements that considering the maximum capacity of storage. The spent fuel elements in the storage pool have different decay times depending on the times of extraction from the core. Assuming conservatively, that the spent fuels of the 5-years decay time would be stored in the lower rack and the spent fuels, of decay time ranged between 10 days and 5 years, would be stored in the upper rack. The dose rate was profiled in the region above the upper rack using SCALE/MAVRIC code applying adjoint flux calculation as a variance reduction technique. The results show that the dose rate values in the region above the pool surface would be lower than the permissible limits.
本研究旨在评价乏燃料临时露天贮存池内的辐射剂量率分布。储存池通过输送通道与主池连接,便于乏燃料在水下输送,避免反应堆工作区域辐射剂量上升。考虑到最大存储容量,该存储池准备存储800个乏燃料元件。储存池中乏燃料元件的衰变时间取决于从堆芯中取出的时间。保守估计,衰变时间为5年的乏燃料储存在下架,衰变时间为10天至5年的乏燃料储存在上架。使用SCALE/MAVRIC代码,应用伴随通量计算作为方差减小技术,在上机架上方区域绘制剂量率分布图。结果表明,池表面以上区域的剂量率值将低于允许限值。
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引用次数: 0
On the role of nuclear quantum gravity in understanding nuclear stability range of Z = 2 to 118 核量子引力在理解Z = 2 ~ 118核稳定范围中的作用
Pub Date : 2020-03-02 DOI: 10.15415/jnp.2019.71005
U. Seshavatharam, S. Lakshminarayana
To understand the mystery of final unification, in our earlier publications, we proposed two bold concepts: 1) There exist three atomic gravitational constants associated with electroweak, strong and electromagnetic interactions. 2) There exists a strong elementary charge in such a way that its squared ratio with normal elementary charge is close to reciprocal of the strong coupling constant. In this paper we propose that, ℏc can be considered as a compound physical constant associated with proton mass, electron mass and the three atomic gravitational constants. With these ideas, an attempt is made to understand nuclear stability and binding energy. In this new approach, with reference to our earlier introduced coefficients k = 0.00642 and f = 0.00189, nuclear binding energy can be fitted with four simple terms having one unique energy coefficient. The two coefficients can be addressed with powers of the strong coupling constant. Classifying nucleons as ‘free nucleons’ and ‘active nucleons’, nuclear binding energy and stability can be understood. Starting from , number of isotopes seems to increase from 2 to 16 at and then decreases to 1 at For Z >= 84, lower stability seems to be, Alower=(2.5 to 2.531)Z.
为了理解最终统一的奥秘,在我们早期的出版物中,我们提出了两个大胆的概念:1)存在与电弱、强和电磁相互作用相关的三个原子引力常数。2)存在一种强基本电荷,其与正常基本电荷的平方比接近于强耦合常数的倒数。在本文中,我们提出,可以把c看作与质子质量、电子质量和三个原子引力常数有关的复合物理常数。有了这些想法,就可以尝试理解核的稳定性和结合能。在这个新方法中,参考我们之前引入的系数k = 0.00642和f = 0.00189,核结合能可以用四个具有唯一能量系数的简单项来拟合。这两个系数可以用强耦合常数的幂来表示。将核子分为“自由核子”和“活动核子”,可以理解核子的结合能和稳定性。从,同位素的数量似乎从2个增加到16个,然后减少到1个,对于Z >= 84,稳定性较低,Alower=(2.5 ~ 2.531)Z。
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引用次数: 5
A GEANT4 Study of a Gamma-ray Collimation Array 伽玛射线准直阵列的GEANT4研究
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72028
Jorge López, S. González, O. Rodriguez, J. Holmes, R. Alarcon
Proton beam therapy uses high-energy protons to destroy cancer cells which are still uncertain about where in the body they hit. A possible way to answer this question is to detect the gamma rays produced during the irradiation and determine where in the body they are produced. This work investigates the use of collimators to determine where the proton interactions occur. GEANT4 is used to simulate the gamma production of a source interacting with a collimator. Each event simulates a number of gammas obtained as a function of the position along the detector. Repeating for different collimator configurations can thus help determine the best characteristics of a detector device.
质子束疗法使用高能质子来摧毁癌细胞,但目前还不确定癌细胞会击中身体的哪个部位。回答这个问题的一个可能的方法是检测在辐照过程中产生的伽马射线,并确定它们在体内产生的位置。这项工作研究了使用准直器来确定质子相互作用发生的位置。GEANT4用于模拟与准直器相互作用的源的伽马产生。每个事件模拟作为沿探测器位置的函数而获得的伽马数。因此,重复不同的准直器配置可以帮助确定探测器设备的最佳特性。
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引用次数: 0
Measurement of Content of 226Ra in Drinking Water From Some States of Mexican Republic by Liquid Scintillation Method 液体闪烁法测定墨西哥部分州饮用水中226Ra含量
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72025
A. Ángeles, Esther Quintero, I. Gaso, C. P. Zepeda, T. Palma, P. V. Rojas
To assess the quality of drinking water in respect to the content of radioactivity, usually is carried out an screening program in the locations of interest, that program consist in pick representative samples of drinking water from the wells in that locations, water samples are analyzed to measuring the gross alpha/beta radioactivity by a low background proportional counter or a liquid scintillation system. When some sample exceeds the normative limit then it must be known which radionuclides are in that sample. Expected radionuclides in water are the NORM (normal occurring radioactive material) from the natural radioactive chains. 226Ra is frequently present in drinking water and is one of most important radionuclide because its “radiotoxicity”, the WHO [World Health Organization, Guidelines for drinking-water Quality, (2016)] recommends a reference level for 226Ra of 1 Bq/L (the dose coefficient for 226Ra is 2.8 x 10-7 Sv/Bq). From a national program of drinking water screening in the Mexican Republic, the samples that exceeded the national normative limits were picked again in the same well and analyzed by LS (liquid Scintillation), using the method of two phases with a not water miscible scintillator cocktail. Results of concentrations of 226Ra from drinking water are presented. In general the content of 226Ra in drinking water samples was lower that the guide values recommended for the WHO.
为了评估饮用水质量的放射性含量,通常在感兴趣的地点进行筛选程序,该程序包括从该地点的井中挑选有代表性的饮用水样本,对水样进行分析,通过低本底比例计数器或液体闪烁系统测量总α / β放射性。当某些样品超过标准限度时,必须知道该样品中含有哪些放射性核素。水中的预期放射性核素是天然放射性链中的NORM(正常发生的放射性物质)。226Ra经常存在于饮用水中,是最重要的放射性核素之一,因为它具有“放射毒性”,世卫组织[世界卫生组织,《饮用水质量指南》(2016)]建议226Ra的参考水平为1 Bq/L (226Ra的剂量系数为2.8 x 10-7 Sv/Bq)。从墨西哥共和国的国家饮用水筛选项目中,对超过国家标准限量的样品在同一井中再次抽取,并采用LS(液体闪烁)分析,采用两相法与非水混相闪烁鸡尾酒。给出了饮用水中226Ra浓度的测定结果。总体而言,饮用水样本中226Ra的含量低于世界卫生组织建议的指导值。
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引用次数: 0
Behavior of Poly-A onto Kaolin Poly-A在高岭土上的行为
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72017
María Guadalupe Torres-Duque, C. Camargo-Raya, A. Negrón-Mendoza, S. Ramos-Bernal
A combination of geochemical variables is necessary to explain the origin of life on Earth. Thus, in this work the sorption of Poly-A on a clay mineral (kaolinite) was studied to get an insight about the sorption capacity at different times and pH values, as well as to confirm the capabilities of the clay to protect the sorbate from an external source of ionizing radiation. Poly-A presented a high percentage of sorption in the clay, especially in acidic environments, and this percentage sharply decrease in alkaline media. On the other hand, Poly-A’s recovery was higher in the system with clay, confirming its protection role.
地球化学变量的组合对于解释地球上生命的起源是必要的。因此,在这项工作中,研究了Poly-A在粘土矿物(高岭石)上的吸附,以了解不同时间和pH值下的吸附能力,并确认粘土保护山梨酸免受外部电离辐射源的能力。Poly-A在粘土中具有较高的吸附率,特别是在酸性环境中,而在碱性介质中吸附率急剧下降。另一方面,Poly-A在有粘土的体系中回收率更高,证实了其保护作用。
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引用次数: 0
Study of CT Images Processing with the Implementation of MLEM Algorithm using CUDA on NVIDIA’S GPU Framework 基于NVIDIA GPU框架的CUDA实现MLEM算法在CT图像处理中的研究
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72021
T. A. Valencia-Pérez, J. M. Hernández-López, E. Moreno-Barbosa, B. D. Celis-Alonso
In medicine, the acquisition process in Computed Tomography Images (CT) is obtained by a reconstruction algorithm. The classical method for image reconstruction is the Filtered Back Projection (FBP). This method is fast and simple but does not use any statistical information about the measurements. The appearance of artifacts and its low spatial resolution in reconstructed images must be considered. Furthermore, the FBP requires of optimal conditions of the projections and complete sets of data. In this paper a methodology to accelerate acquisition process for CT based on the Maximum Likelihood Estimation Method (MLEM) algorithm is presented. This statistical iterative reconstruction algorithm uses a GPU Programming Paradigms and was compared with sequential algorithms in which the reconstruction time was reduced by up to 3 orders of magnitude while preserving image quality. Furthermore, they showed a good performance when compared with reconstruction methods provided by commercial software. The system, which would consist exclusively of a commercial laptop and GPU could be used as a fast, portable, simple and cheap image reconstruction platform in the future.
在医学中,计算机断层扫描图像(CT)的采集过程是通过重构算法获得的。经典的图像重建方法是滤波后投影(FBP)。该方法快速简单,但不使用任何有关测量的统计信息。重建图像中伪影的出现及其低空间分辨率是必须考虑的问题。此外,FBP还要求预测的最优条件和完整的数据集。本文提出了一种基于极大似然估计(MLEM)算法加快CT采集过程的方法。该统计迭代重建算法使用GPU编程范式,并与序列算法进行了比较,在保持图像质量的同时,重建时间减少了3个数量级。此外,与商业软件提供的重建方法相比,它们表现出良好的性能。该系统仅由商用笔记本电脑和GPU组成,未来可作为快速、便携、简单、廉价的图像重建平台。
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引用次数: 1
Radiation Induced Reactions of Succinic Acid in Aqueous Solution: An Agent-Based Model 琥珀酸在水溶液中的辐射诱导反应:基于试剂的模型
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72014
A. L. Rivera, Sergio Ramos-Beltran, A. Negrón-Mendoza
An approach to studying the formation of critical bio-organic compounds in the early Earth is to simulate in the laboratory possible processes that may occur in primitive scenarios. In this context, it can be studied the evolution of succinic acid in an aqueous media exposed to gamma radiation, as starting material produced more complex prebiotic molecules. To describe the products generated by the interaction of the different elements under radiation, there is a mathematical model that considers chemical reactions as nonlinear ordinary differential equations based on the mass balance of all the species, that has been implemented here by an agent-based model. In this simulation, each chemical species involved is considered as an agent that can interact with other species with known reaction rates, and the radiation is taken as a factor that promotes product formation. The results from the agentbased model are compared with the molar concentrations of succinic acid, and its products obtained in the lab. Simulation shows the exponential decomposition of succinic acid due to gamma radiation at room temperature in agreement with the laboratory model.
研究地球早期关键生物有机化合物形成的一种方法是在实验室中模拟在原始情景中可能发生的过程。在这种情况下,可以研究琥珀酸在暴露于伽马辐射的水介质中的演化,作为起始材料产生更复杂的益生元分子。为了描述不同元素在辐射作用下相互作用产生的产物,有一个数学模型,该模型将化学反应视为基于所有物种的质量平衡的非线性常微分方程,该模型在这里由基于代理的模型实现。在此模拟中,所涉及的每种化学物质都被认为是一种可以与已知反应速率的其他物质相互作用的物质,辐射被认为是促进产物形成的因素。将该模型的计算结果与琥珀酸的摩尔浓度及其在实验室中得到的产物进行了比较。模拟结果表明,琥珀酸在室温下受伽马辐射的指数分解与实验室模型一致。
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引用次数: 0
Stability of Glycine in Saline Solutions Exposed to Ionizing Radiation 甘氨酸在电离辐射下盐溶液中的稳定性
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72009
Laura Patricia Cruz-Cruz, A. Negrón-Mendoza, A. Heredia-Barbero
The stability of biologically important molecules, such as amino acids, being subjected to highradiation fields is relevant for chemical evolution studies. Bodies of water were very important in the primitive Earth. In these bodies, the presence of dissolved salts, together with organic molecules, could influence the behavior of the systems in prebiotic environments.The objective of this work is to examine the influence of sodium chloride on the stability of the amino acid glycine when subjected to high radiation doses. The analysis of the irradiated samples was followed by HPLC coupled with a UV-VIS detector. The results show that glycine in aqueous solutions (without oxygen) decomposed around 90% at a dose of 91 kGy. In the presence of salts, up to 80% of the amino acid was recovered at the same dose. Laboratory simulations demonstrate a protective role for sodium chloride (specifically the chloride ion) to glycine against an external source of ionizing radiation.
生物学上重要的分子,如氨基酸,在高辐射场下的稳定性与化学进化研究有关。水体在原始地球是非常重要的。在这些生物体中,溶解的盐和有机分子的存在可能会影响益生元环境中系统的行为。本研究的目的是研究高剂量辐射下氯化钠对氨基酸甘氨酸稳定性的影响。用高效液相色谱法和紫外可见检测器对辐照样品进行分析。结果表明,在91 kGy的剂量下,甘氨酸在无氧水溶液中分解率约为90%。在盐存在的情况下,以相同剂量回收了高达80%的氨基酸。实验室模拟证明了氯化钠(特别是氯离子)对甘氨酸抵抗外部电离辐射源的保护作用。
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引用次数: 0
Feasibility of Formation of Ge1-x-y Six Sny Layers With High Sn Concentration via Ion Implantation 离子注入制备高锡浓度Ge1-x-y六Sny层的可行性
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72006
Randall L. Holliday, Joshua M. Young, Satyabrata Singh, F. McDaniel, B. Rout
By increasing the Sn concentration in Ge1-ySny and Ge1-x-ySixSny systems, these materials can be tuned from indirect to direct bandgap along with increasing electronic and photonic properties. Efforts have been made to synthesize Sn-Ge and Ge-Si-Sn structures and layers to produce lower energy direct bandgap materials. Due to low solid solubility of Sn in Ge and Si-Ge layers, high concentrations of Sn are not achieved by traditional synthesis processes such as chemical vapor deposition or molecular beam epitaxy. Implantation of Sn into Si-Ge systems, followed by rapid thermal annealing or pulse laser annealing, is shown to be an attractive technique for increasing Sn concentration, which can increase efficiencies in photovoltaic applications. In this paper, dynamic ion-solid simulation results are presented. Simulations were performed to determine optimal beam energy, implantation order, and fluence for a multi-step, ion-implantation based synthesis process.
通过增加Ge1-ySny和Ge1-x-ySixSny体系中的Sn浓度,这些材料可以从间接带隙调谐到直接带隙,同时增加电子和光子特性。人们努力合成Sn-Ge和Ge-Si-Sn结构和层,以生产低能量的直接带隙材料。由于Sn在Ge和Si-Ge层中的固体溶解度较低,通过化学气相沉积或分子束外延等传统合成工艺无法获得高浓度的Sn。将锡注入Si-Ge体系,然后进行快速热退火或脉冲激光退火,是提高锡浓度的一种有吸引力的技术,可以提高光伏应用的效率。本文给出了动态离子固体的模拟结果。为了确定多步骤离子注入合成过程的最佳束流能量、注入顺序和影响,进行了模拟。
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引用次数: 0
Development and Validation of an X-ray Imaging Detector for Digital Radiography at Low Resolution 低分辨率数字x射线成像探测器的研制与验证
Pub Date : 2020-02-28 DOI: 10.15415/jnp.2020.72023
A. R. Reyes, G. H. Corral, Elsa G. Ordoñez Casanova, H. Mandujano, Uzziel Caldiño Herrera
Digital X-ray detectors are required in different sciences and applications, however many high quality devices are expensive although high-resolution images are not always required. We present an easy way to build a detector capable of forming X-ray digital images and video with a very large area (18×18 cm2). The detector is formed by three main components: scintillator, optics lenses and CCD sensor. Basically, the device converts the X-rays into visible light which is then collected by the CCD sensor. The scintillator is Gadox type, from Carestream®, 18×18 cm2, regular type, lambda 547 nm. The optics lenses are generic, with manual focus and widely visual field. The CCD sensor has a size of 1/3″, 752 × 582 pixels, monochrome, 20 FPS, 12 bits ADC and pixel size of 3.8 μm. With the built detector and an X-ray source, we formed an X-ray imaging detection system to generate digital radiographs of biological or inert objects-examples are given-, as well as real-time X-ray video. Additionally, the spatial resolution limit was measured in terms of Modulation Transfer Function by the method of opaque edge from a lead sheet with a result of 1.1 Lp/mm. Finally using a filter, the focal spot of the X-ray source is measured, resulting in a diameter of 0.9 mm (FWHM).
数字x射线探测器在不同的科学和应用中都需要,然而许多高质量的设备都很昂贵,尽管并不总是需要高分辨率的图像。我们提出了一种简单的方法来建立一个探测器,能够形成一个非常大的面积(18×18 cm2)的x射线数字图像和视频。该探测器主要由闪烁体、光学透镜和CCD传感器三部分组成。基本上,该设备将x射线转换成可见光,然后由CCD传感器收集。闪烁体为Gadox型,来自Carestream®,18×18 cm2,常规型,λ 547 nm。光学镜头为通用型,手动对焦,视野宽广。CCD传感器尺寸为1/3″,752 × 582像素,单色,20fps, 12位ADC,像素尺寸为3.8 μm。利用内置的探测器和x射线源,我们形成了一个x射线成像检测系统,以生成生物或惰性物体的数字x射线照片-给出了示例-以及实时x射线视频。此外,采用导联片不透明边缘法,用调制传递函数测量了空间分辨率极限,结果为1.1 Lp/mm。最后利用滤光片测量x射线源的焦点光斑,得到直径0.9 mm (FWHM)。
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引用次数: 0
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Journal of Nuclear Physics, Material Sciences, Radiation and Applications
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