嫦娥一号绕月伽玛能谱分析技术研究
摘要
月球具有可供人类开发利用的各种矿产资源,是对地球资源的重要补充和储备,对人类社会的可持续发展具有深远影响。采用放射性伽玛能谱分析技术,探测月球表面有开发利用价值的U,Th,K,Fe,Ti,Al等元素的含量与分布,初步编制月球表面元素和物质类型的分布图,是嫦娥一号月球探测卫星的四大科学目标之一[1]。
在嫦娥一号卫星环绕月球飞行约一年的工作期间,γ射线谱仪将反复飞经月球各个区域,将飞经每一个区域的探测数据累加和处理,就得到我们要进行处理的能谱数据[2]。
月表伽玛射线主要有三个来源:月球表面含有铀、钍、钾等天然放射性元素的同位素由于衰变直接释放出的天然γ射线[3];银河宇宙射线(GCR)与元素发生反应,核素受到GCR粒子激发后,发生非弹性散射,产生该核素在地球上不具有的特征γ谱线;元素捕获吸收低能中子,会释放一种或多种的γ射线。相对常规地表探测所研究的30-3000keV范围伽玛能谱受非弹性散射产生的γ射线和元素捕获中子释放γ射线的影响[4],月球上的核素能比它在地球上释放更多特征能量的γ射线。例如,通过GCR粒子入射能使O产生6.129MeV的高能特征能量γ射线,而此特征谱线在通常地表伽玛能谱探测时是很难发现的。与地面探测相比,月球表面伽玛射线能量范围更广。
对嫦娥一号上γ射线谱仪返回的探测数据,我们将参照野外地面伽玛能谱的处理方法进行处理。本文的主要成果有:
(1)结合野外地面伽玛射线全谱测量原理,分析了月球表面全谱测量的方法,和具体测量仪器的性能。
(2)结合月球表面物质发射伽玛射线的机理和物理模型,研究了月表物质伽玛射线辐射特征、伽玛射线能谱与物质成分的关系,并建立了相应的分析模型。
(3)通过对GRS科学数据预处理流程的分析,对3级数据产品进行了初步处理,包括单条谱线的分段平滑、去本底、寻峰和1790条谱线的整体平滑、去本底。
(4)通过对3级数据产品的初步处理结果分析,提出了元素相对含量分析模型,并对特定的元素展开全月数据的整体分析。
本文根据现有的伽玛能谱数据进行了前期分析处理,为后期的数据处理和元素精确含量计算打下了基础。同时,元素相对含量分布的结果也对以后登月和采样提供了科学依据。
文章总体分为以下六个部分:
(1)引言部分,对题目来源、选题背景、国内外研究现状等进行了描述,并对嫦娥一号绕月伽玛能谱分析技术研究目的、研究内容和技术路线进行了分析和说明。
(2)对月球伽马射线来源、月球伽玛射线测量原理、以及测量仪器的性能进行了简单介绍。
(3)对GRS科学数据预处理流程以及GRS 0级数据、1级数据、2级数据产品进行详细阐述,包括数据的输入、处理方法以及输出数据等。
(4)GRS 3级数据产品处理部分,具体包括GRS 3级数据的来源、单条谱线平滑、单条谱线去本底、单条谱线寻峰、3级数据整体平滑、3级数据整体去本底。
(5)月球表面元素相对含量分布部分,包括谱线拟合、求特征峰面积和计算月表元素相对含量分布。
(6)结论部分,包括对嫦娥一号绕月伽玛能谱分析技术研究的说明和总结,并对后期探测提出建议。
The moon has a variety of mineral resources for human development, it’s an important complement to the Earth's resources and reserves and has far-reaching impact on the sustainable development of human society. Detecting the distribution and relative content of U, Th, K, Fe, Ti, Al and some other useful elements on lunar surface using radioactive gamma spectrometry analysis and drawing the distribution of elements and material types on lunar surface are part of Chang'e 1 lunar probe satellite's scientific goals.
Chang'e 1 satellite flied around the moon for about one year and the gamma-ray spectrometer on Chang'e 1 repeatedly fly over the moon in various regions. We can get the spectrum data to deal with through accumulation the detection data of each area.
There are three sources of gamma rays on lunar surface: the lunar surface contains uranium, thorium, potassium and other natural decay of radioactive isotopes which directly release natural gamma-ray; the galactic cosmic rays (GCR) reacting with the elements on the lunar surface, which will occur Inelastic scattering and produce characteristics of gamma lines that not exist on earth; when elements on lunar capture and absorb low-energy neutron , it will release one or more kind of characteristics gamma-ray. The elements on lunar will release more gamma-ray than that of earth, Influenced by Inelastic scattering and neutron capture in the range of 30-3000KeV. For example, by GCR particles incident O can release characteristics gamma-ray of 6.129Mev, which not exists on earth. The energy of gamma-ray on lunar has a larger range than earth.
We will compare existing field gamma-ray spectrometer when processing the data of gamma-ray return by Chang'e 1. There are the consequents of this paper:
(1) Combined with field gamma-ray measurement principle, we analyzed the measurement method on lunar surface and the specific performance of measuring instruments.
(2) Combined with gamma-ray emission mechanism and physical model on lunar surface, we studied characteristics of gamma-ray radiation of material on lunar surface and the relationship between material composition and gamma-ray spectroscopy.
(3) On the analysis of pretreatment process on the three grade GRS data, we did initial processing of three grade data products, including smoothing by divided, removing background, peak search of single line and smoothing and removing backgrounds of total 1790 lines.
(4) On the preliminary analysis of results level 3 data products, we proposed analysis model of relative content and did overall analysis of specific elements.
In this paper we did pre-analytical processing based on existing gamma spectrometry data, which provide a good foundation for the later data processing and the Calculation of Exact content. Meanwhile, the results of relative content of elements provided scientific basis for moon landing and sampling.
This paper is divided into the following six parts:
(1) Introduction of the source of the topic, the research background, and status, etc. This part analyzed the purpose, contents, technical method of this research.
(2) Introduction of gamma-ray source on the lunar surface, lunar gamma-ray measurement principle and the performance of measuring instruments.
(3) Introduction of pretreatment process of scientific GRS data and elaboration of level 0 to level 2 data including data input, processing method and data output.
(4) Part of GRS data processing of level 3,including source of level 3 data, smoothing of single line, removing background of single line, peak search of single line, smoothing of level 3 data, removing background of level 3 data.
(5) This part described the content calculation of elements distribution, including line fitting, calculation of Characteristic peak area and relative distribution of elements.
(6) Conclusion, including description and summary of gamma spectrometry analysis, and post-detection recommendations.
在嫦娥一号卫星环绕月球飞行约一年的工作期间,γ射线谱仪将反复飞经月球各个区域,将飞经每一个区域的探测数据累加和处理,就得到我们要进行处理的能谱数据[2]。
月表伽玛射线主要有三个来源:月球表面含有铀、钍、钾等天然放射性元素的同位素由于衰变直接释放出的天然γ射线[3];银河宇宙射线(GCR)与元素发生反应,核素受到GCR粒子激发后,发生非弹性散射,产生该核素在地球上不具有的特征γ谱线;元素捕获吸收低能中子,会释放一种或多种的γ射线。相对常规地表探测所研究的30-3000keV范围伽玛能谱受非弹性散射产生的γ射线和元素捕获中子释放γ射线的影响[4],月球上的核素能比它在地球上释放更多特征能量的γ射线。例如,通过GCR粒子入射能使O产生6.129MeV的高能特征能量γ射线,而此特征谱线在通常地表伽玛能谱探测时是很难发现的。与地面探测相比,月球表面伽玛射线能量范围更广。
对嫦娥一号上γ射线谱仪返回的探测数据,我们将参照野外地面伽玛能谱的处理方法进行处理。本文的主要成果有:
(1)结合野外地面伽玛射线全谱测量原理,分析了月球表面全谱测量的方法,和具体测量仪器的性能。
(2)结合月球表面物质发射伽玛射线的机理和物理模型,研究了月表物质伽玛射线辐射特征、伽玛射线能谱与物质成分的关系,并建立了相应的分析模型。
(3)通过对GRS科学数据预处理流程的分析,对3级数据产品进行了初步处理,包括单条谱线的分段平滑、去本底、寻峰和1790条谱线的整体平滑、去本底。
(4)通过对3级数据产品的初步处理结果分析,提出了元素相对含量分析模型,并对特定的元素展开全月数据的整体分析。
本文根据现有的伽玛能谱数据进行了前期分析处理,为后期的数据处理和元素精确含量计算打下了基础。同时,元素相对含量分布的结果也对以后登月和采样提供了科学依据。
文章总体分为以下六个部分:
(1)引言部分,对题目来源、选题背景、国内外研究现状等进行了描述,并对嫦娥一号绕月伽玛能谱分析技术研究目的、研究内容和技术路线进行了分析和说明。
(2)对月球伽马射线来源、月球伽玛射线测量原理、以及测量仪器的性能进行了简单介绍。
(3)对GRS科学数据预处理流程以及GRS 0级数据、1级数据、2级数据产品进行详细阐述,包括数据的输入、处理方法以及输出数据等。
(4)GRS 3级数据产品处理部分,具体包括GRS 3级数据的来源、单条谱线平滑、单条谱线去本底、单条谱线寻峰、3级数据整体平滑、3级数据整体去本底。
(5)月球表面元素相对含量分布部分,包括谱线拟合、求特征峰面积和计算月表元素相对含量分布。
(6)结论部分,包括对嫦娥一号绕月伽玛能谱分析技术研究的说明和总结,并对后期探测提出建议。
The moon has a variety of mineral resources for human development, it’s an important complement to the Earth's resources and reserves and has far-reaching impact on the sustainable development of human society. Detecting the distribution and relative content of U, Th, K, Fe, Ti, Al and some other useful elements on lunar surface using radioactive gamma spectrometry analysis and drawing the distribution of elements and material types on lunar surface are part of Chang'e 1 lunar probe satellite's scientific goals.
Chang'e 1 satellite flied around the moon for about one year and the gamma-ray spectrometer on Chang'e 1 repeatedly fly over the moon in various regions. We can get the spectrum data to deal with through accumulation the detection data of each area.
There are three sources of gamma rays on lunar surface: the lunar surface contains uranium, thorium, potassium and other natural decay of radioactive isotopes which directly release natural gamma-ray; the galactic cosmic rays (GCR) reacting with the elements on the lunar surface, which will occur Inelastic scattering and produce characteristics of gamma lines that not exist on earth; when elements on lunar capture and absorb low-energy neutron , it will release one or more kind of characteristics gamma-ray. The elements on lunar will release more gamma-ray than that of earth, Influenced by Inelastic scattering and neutron capture in the range of 30-3000KeV. For example, by GCR particles incident O can release characteristics gamma-ray of 6.129Mev, which not exists on earth. The energy of gamma-ray on lunar has a larger range than earth.
We will compare existing field gamma-ray spectrometer when processing the data of gamma-ray return by Chang'e 1. There are the consequents of this paper:
(1) Combined with field gamma-ray measurement principle, we analyzed the measurement method on lunar surface and the specific performance of measuring instruments.
(2) Combined with gamma-ray emission mechanism and physical model on lunar surface, we studied characteristics of gamma-ray radiation of material on lunar surface and the relationship between material composition and gamma-ray spectroscopy.
(3) On the analysis of pretreatment process on the three grade GRS data, we did initial processing of three grade data products, including smoothing by divided, removing background, peak search of single line and smoothing and removing backgrounds of total 1790 lines.
(4) On the preliminary analysis of results level 3 data products, we proposed analysis model of relative content and did overall analysis of specific elements.
In this paper we did pre-analytical processing based on existing gamma spectrometry data, which provide a good foundation for the later data processing and the Calculation of Exact content. Meanwhile, the results of relative content of elements provided scientific basis for moon landing and sampling.
This paper is divided into the following six parts:
(1) Introduction of the source of the topic, the research background, and status, etc. This part analyzed the purpose, contents, technical method of this research.
(2) Introduction of gamma-ray source on the lunar surface, lunar gamma-ray measurement principle and the performance of measuring instruments.
(3) Introduction of pretreatment process of scientific GRS data and elaboration of level 0 to level 2 data including data input, processing method and data output.
(4) Part of GRS data processing of level 3,including source of level 3 data, smoothing of single line, removing background of single line, peak search of single line, smoothing of level 3 data, removing background of level 3 data.
(5) This part described the content calculation of elements distribution, including line fitting, calculation of Characteristic peak area and relative distribution of elements.
(6) Conclusion, including description and summary of gamma spectrometry analysis, and post-detection recommendations.
引文
[1]欧阳自远著.月球科学概论[M].北京:中国宇航出版社,2005
[2]国防科工委月球探测工程中心.中国探月[M].北京:科学出版社,2007.
[3]葛良全.核辐射测量方法[M].成都:成都理工大学核技术与自动化工程学院印刷,2007.
[4]方方.野外地面伽玛射线全谱测量技术研究. [D].成都:成都理工大学(成都),2001
[5] Norman J. Hubbard, Danuta Woloszyn. Orbital gamma-ray data and large-scale lunar problems[J]. Physics of the Earth and Planetary Interiors, 1977, 15:287-302.
[6] Zou Yongliao, Xu Lin, Ouyang Ziyuan. KREEP rocks[J]. Chinese J Geochem, 2004, 23(1):65-70.
[7] Warren Y H, Wasson J T. The origin of KREEP[J]. Rev Geophys Space Phys, 1979, 17(1):73-88.
[8] Warren Y H. The magma ocean concept and Lunar evolution[J].. Ann Rev Earth Planet Sci, 1985,13:201- 240.
[9] T. Ma, J. Chang, N. Zhang. Discovery of 13 New Variable Stars in the Field of the Open Cluster NGC 2168 (M35)[J].Advances in Space Research, 2008, 42:347-349.
[10] LI Yongquan,LIU Jianzhong,OUYANG Ziyuan. Natural radioactive thorium distribution at the lunar surface and it's primary inhomogeneity of chemical composition[J].Acta Petrologica Sinica,2007,23(5):1169-1174.
[11] W. Zhang, M.Zahringer, K. Ungar. Statistical analysis of uncertainties of gamma-peak identification[J]. Applied Radiation and Isotopes, 2008, 66:1695-1701.
[12] W.C. Feldman, B.L. Barraclough, K.R. Fuller. The Dynamic Albedo of Neutrons (DAN) Experiment for NASA's 2009 Mars Science Laboratory[J]. Astrobiology , 2008, 8 (3) : 605-612
[13]欧阳自远.月球探测的进展与我国月球探测的科学目标[J].贵州工业大学学报(自然科学版),2003(6):1-7.
[14]欧阳自远著.月球——人类走进深空的前哨站[M].北京:科学出版社,2002
[15] Anderson J D, Schubert G, Jacobson R A, et al. Distribution of Rock, Metals, and Ices in Callisto[J]. Science, 1998, 8 (3) : 1573-1576.
[16] Vasavada A R, Paige D A and Wood S E. Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits[J]. Icsrus, 1999,141 (2) : 179-193.
[17]放射性勘探,成都地质学院编译.
[18] Maxwell E L. Metstat-the Solar Radition Model Used in the production of the National Solar Radition Data Base(NSRDB) [J]. Solar Energy, 1998,26 (4) : 263-279.
[19]舒双宝.月球伽玛射线谱仪的研制及其性能[J].天文学报.2006,3
[20] ZHU Meng-Hua, LIU Liang-Gang, YOU Zhong. Study of Processing Overlapped Gamma-ray Peaks by Differential Method[J]. Journal of Macau University of Science and Technology, 2007,12, 1(2):1-7
[21]任爱阁.自然伽玛能谱测井谱解析方法研究[D].北京:中国石油大学(北京),2007
[22]艾宪芸.蹄锌镉探测器性能分析及其γ谱解析方法研究[D].北京:清华大学,2005.
[2]国防科工委月球探测工程中心.中国探月[M].北京:科学出版社,2007.
[3]葛良全.核辐射测量方法[M].成都:成都理工大学核技术与自动化工程学院印刷,2007.
[4]方方.野外地面伽玛射线全谱测量技术研究. [D].成都:成都理工大学(成都),2001
[5] Norman J. Hubbard, Danuta Woloszyn. Orbital gamma-ray data and large-scale lunar problems[J]. Physics of the Earth and Planetary Interiors, 1977, 15:287-302.
[6] Zou Yongliao, Xu Lin, Ouyang Ziyuan. KREEP rocks[J]. Chinese J Geochem, 2004, 23(1):65-70.
[7] Warren Y H, Wasson J T. The origin of KREEP[J]. Rev Geophys Space Phys, 1979, 17(1):73-88.
[8] Warren Y H. The magma ocean concept and Lunar evolution[J].. Ann Rev Earth Planet Sci, 1985,13:201- 240.
[9] T. Ma, J. Chang, N. Zhang. Discovery of 13 New Variable Stars in the Field of the Open Cluster NGC 2168 (M35)[J].Advances in Space Research, 2008, 42:347-349.
[10] LI Yongquan,LIU Jianzhong,OUYANG Ziyuan. Natural radioactive thorium distribution at the lunar surface and it's primary inhomogeneity of chemical composition[J].Acta Petrologica Sinica,2007,23(5):1169-1174.
[11] W. Zhang, M.Zahringer, K. Ungar. Statistical analysis of uncertainties of gamma-peak identification[J]. Applied Radiation and Isotopes, 2008, 66:1695-1701.
[12] W.C. Feldman, B.L. Barraclough, K.R. Fuller. The Dynamic Albedo of Neutrons (DAN) Experiment for NASA's 2009 Mars Science Laboratory[J]. Astrobiology , 2008, 8 (3) : 605-612
[13]欧阳自远.月球探测的进展与我国月球探测的科学目标[J].贵州工业大学学报(自然科学版),2003(6):1-7.
[14]欧阳自远著.月球——人类走进深空的前哨站[M].北京:科学出版社,2002
[15] Anderson J D, Schubert G, Jacobson R A, et al. Distribution of Rock, Metals, and Ices in Callisto[J]. Science, 1998, 8 (3) : 1573-1576.
[16] Vasavada A R, Paige D A and Wood S E. Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits[J]. Icsrus, 1999,141 (2) : 179-193.
[17]放射性勘探,成都地质学院编译.
[18] Maxwell E L. Metstat-the Solar Radition Model Used in the production of the National Solar Radition Data Base(NSRDB) [J]. Solar Energy, 1998,26 (4) : 263-279.
[19]舒双宝.月球伽玛射线谱仪的研制及其性能[J].天文学报.2006,3
[20] ZHU Meng-Hua, LIU Liang-Gang, YOU Zhong. Study of Processing Overlapped Gamma-ray Peaks by Differential Method[J]. Journal of Macau University of Science and Technology, 2007,12, 1(2):1-7
[21]任爱阁.自然伽玛能谱测井谱解析方法研究[D].北京:中国石油大学(北京),2007
[22]艾宪芸.蹄锌镉探测器性能分析及其γ谱解析方法研究[D].北京:清华大学,2005.