Background deduction of the Chang'E-1 gamma-ray spectrometer data  

作　　者：ZHANG Liyan LI Chunlai LIU Jinazhong ZOU Yongliao OUYANG Ziyuan 

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China [2]Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China [3]Graudate University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Journal Of Geochemistry》2012年第3期234-241,共8页中国地球化学学报

基　　金：supported by the Na-tional High Technology Research and Development Program of China (Nos. 2008AA12A212,2010AA122201 and 2010AA122202);the National Natural Science Foundation of China (Nos.41040031 and 40904024)

摘　　要：Gamma-ray spectrometer(GRS) is used to detect the elemental abundances and distributions on the lunar surface.To derive the elemental abundances,it is vital to acquire background gamma rays except lunar gamma rays.So GRS would observe background spectra in the course of earth-moon transfer on schedule.But in fact,GRS was not switched on in the course of flying toward the moon.After the CE-1 probe finished one-year mission,GRS car-ried out a test on background data on November 21?22,2008.The authors did conduct research on the methods of background deduction using 2105 hours of usable gamma-ray spectra acquired at the 200-km orbital height by the GRS and more than 5 hours of gamma-ray spectra acquired in the GRS background test.The final research results showed that the method of deducting the background using the minimum counts in the CE-1 GRS pixels is optimal for the elements,U,K and Th.The method applies to such a case that the elemental abundances in the pixel with the minimum counting rate are 0 μg/g and the continuum background counts are constant over the Moon.Based on the method of background deduction,the full energy peak counts of U,K,and Th are calculated.Gamma-ray spectrometer（GRS） is used to detect the elemental abundances and distributions on the lunar surface.To derive the elemental abundances,it is vital to acquire background gamma rays except lunar gamma rays.So GRS would observe background spectra in the course of earth-moon transfer on schedule.But in fact,GRS was not switched on in the course of flying toward the moon.After the CE-1 probe finished one-year mission,GRS car-ried out a test on background data on November 21？22,2008.The authors did conduct research on the methods of background deduction using 2105 hours of usable gamma-ray spectra acquired at the 200-km orbital height by the GRS and more than 5 hours of gamma-ray spectra acquired in the GRS background test.The final research results showed that the method of deducting the background using the minimum counts in the CE-1 GRS pixels is optimal for the elements,U,K and Th.The method applies to such a case that the elemental abundances in the pixel with the minimum counting rate are 0 μg/g and the continuum background counts are constant over the Moon.Based on the method of background deduction,the full energy peak counts of U,K,and Th are calculated.

关 键 词：背景扣除 γ射线谱仪 嫦娥一号 伽玛射线 表面元素 元素丰度 GRS 光谱仪 

分 类 号：P172.3[天文地球—天文学] X831[环境科学与工程—环境工程]