Improved Measurement Performance of Inorganic Elements in Coal by Laser-Induced Breakdown Spectroscopy Coupled with Internal Standardization

Laser-induced breakdown spectroscopy was employed to determine the inorganic elements in coal. To improve the measurement’s accuracy and precision, a new internal stan?dardization scheme, which we named changed internal standardization, was compared with the traditional internal standardization and no internal standardization for the analysis of inorganic el?ements. The new internal standardization scheme used the atomic line of carbon at 247.86 nm and the molecular band of CN at 388.34 nm and C2 at 516.32 nm to normalize the lines of inorganic elements that were distributed in the same spectral channel. The performance of the utilization of the new internal standardization scheme was evaluated using a set of coal samples, including twenty calibration samples and five validation samples. The results show that the coefficients of determination R2 and the slope of calibration models coupled with changed internal standard?ization are better than that of the calibration models coupled with fixed internal standardization and no internal standardization. Moreover, the measurement accuracy and reproducibility of changed internal standardization for the analysis of five validation samples also yielded further improvement. The results that we obtained suggest that changed internal standardization could compensate for the matrix effects, as well as the influence of the difference in the spectral response of the light collection system.     

Online calibration of laser-induced breakdown spectroscopy for detection of heavy metals in water

In order to reduce the fluctuation of LIBS detection spectrum of liquid sample, the full-spectrum sum method and the internal standardization method is adopted, using an equal-RSD normalization algorithm to calibrate the detection spectrum. Experiment result shows that the full-spectrum sum method reduced the RSD of parallel samples of Cd and Cr to 9.4％ and 11.06％ from 28.32％ and 31.93％ respectively, yielded better overall calibration than the singleelement internal standardization approach, thereby suggesting that the former method is convenient and effective for online calibration of LIBS for detection of aqueous heavy metals.     

瞬发γ射线中子活化分析的现状与发展

概述了瞬发γ射线中子活化分析(PGNAA)的现状与发展，重点介绍了PGNAA的基本原理，国际上已建的PGNAA装置概况、PGNAA方法学中的单比较器k0法和高能γ射线的效率刻度技术，以及PGNAA在新材料、环境样品、生物和药物以及矿物中H、B、N、Cl等轻元素分析测定方面的日益发展的应用状况。此外，还介绍了在中国原子能科学研究院重水研究堆上建立的热中子束PGNAA实验装置。     

A GUPIX-based approach to interpreting the PIXE-plus-XRF spectra from the Mars Exploration Rovers: I. Homogeneous standards

A new fitting code has been developed on the basis of GUPIX for application to alpha-particle X-ray spectrometers, which employ simultaneously two excitation mechanisms - XRF and PIXE - for elemental analysis of a single sample, and which are principal analytical instruments on the Mars Exploration Rovers. We present some of the basic aspects of our approaches to spectrum fitting, and we use a subset of the original calibration spectra from the MER mission to test our approach to standardization. This test is limited to results from homogeneous standards such as pure elements, oxides and chlorides, and simple minerals that comprise a single phase. The important, additional issues of multiple mineral phases that arise when geochemical reference materials are used as standards are dealt with in the subsequent paper. It is shown that an accurate standardization can be achieved with only minimal resort to empirical corrections. Attention is paid to fitting of the Compton scatter feature and to the extraction of the Compton-Rayleigh scatter ratio, because the latter quantity is the basis of our method for determining “invisible” light element (water, ice and carbonate) content of Martian samples.     

Standardization of nuclear power plants—its difficulties in the international market

With the maturing of the nuclear industry, significant efforts are being made to standardize nuclear power plant designs. This paper considers the possibilities of standardization on an international level, explaining the advantages for cooperation, the present difficulties in adopting standardization on a national and international basis and the experience of a nuclear vendor in adapting his standard U.S. reactor system to the German market.The conclusion reached is that even though standardization on an international basis has worthwhile merits, the significant differences in safety and licensing requirements, utility preferences and standards, and national interests and capabilities will prevent standardization of the complete plant in the near future. Standardization of components, subsystems and systems, however, appears possible on both the national and international level in the near term.     

Re-estimation of absolute gamma ray intensities of ^56Mn using k0-standardization

The thermal neutron capture gamma ray facility at Pakistan Research Reactor （PARR-1） is being used for the re-estimation of various properties like capture cross-sections, resonance integral, absolute gamma intensities, etc. of different isotopes. The data for gamma ray transitions from the capture of thermal neutrons by ^55Mn are not in good agreement specifically below 2 MeV. So there is a need to re-estimate its intensities with better accuracy. Analytical grade MnCl2 powder and high purity Mn metal pieces were used in this study. Standard ^152Eu and ^60Co radioactive sources as well as thermal neutron capture γ-rays in chlorine were chosen for efficiency calibration. The k0 standardization technique was applied for these measurements to eliminate systematic errors in efficiencies. Chlorine also acted as a comparator in k0-factor calculations. The results have been tabulated for the main gamma rays from ^56Mn in the low as well as in the medium energy regions. The absolute intensities are in good agreement with most of the reported values.     

核技术利用领域辐射安全管理标准化建设

根据核技术利用领域的技术与生产特点, 讨论了在核技术利用领域开展标准化工作的意义;分析了核技术利用领域辐射安全管理标准化建设中存在的问题, 总结了试点省份实践中的工作经验, 提出标准化建设的思路。为我国核技术利用领域辐射安全管理标准化的推广和持续改进提供参考。     

运行核电厂安全生产标准化管理信息系统的研发

为了解决运行核电厂安全生产标准化建设中信息共享难、工作效率低及各类大量数据统计分析难的问题,研发了运行核电厂安全生产标准化管理信息系统。结果表明,应用该管理信息系统加快了职能处室之间的信息传递,实现了信息共享;优化了管理流程,提高了工作效率;解决了安全生产标准化建设过程中各类大量数据的统计分析问题。      

中国实验快堆固定式γ探测器现场校准技术研究

通过研究γ探测器实验室校准的技术条件，在考虑中国实验快堆（CEFR）现场校准的各种影响因素后，根据CEFR实际情况组装一套校准专用装置，并选择替代法为现场校准方法，选择合适的参考仪器对CEFR厂房内固定式γ探测器进行现场校准实验。结果表明，采用CEFR校准专用装置和建立的现场校准方法可满足固定式γ探测器的现场校准要求。     

γ扫描测量等效活度的校准方法研究

本文提出了采用标准线源代替标准体源对装置进行效率校准的等效活度校准方法。利用蒙特卡罗模拟方法,研究了不同介质密度和特征γ射线能量对线源校准位置的影响。测量实验结果与模拟计算结果吻合,证实了这种方法是一种介于常规效率校准与无源效率校准两种方法之间的等效校准技术。