- LRK -
Figure 3 First X-ray fluorescent spectrum of lunar regolith obtained by APXS (image by IHEP) SEE LINK BELOW FOR MORE IMAGES. - LRK -
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Text & Images:
http://english.ihep.cas.cn/
CHANG’E-3 SATELLITE PAYLOAD APXS OBTAINED ITS FIRST SPECTRUM OF LUNAR REGOLITH
The Active Particle-induced X-ray Spectrometer (APXS), carried by the Yutu rover of the Chang’e-3 satellite, got its first X-ray fluorescence spectrum of lunar regolith around the landing site on December 25, 2013.
An initial analysis indicates that eight major rock-forming elements (Mg, Al, Si, K, Ca, Ti, Cr and Fe) and at least 3 minor elements (Sr, Y and Zr) of the Moon can be identified in this spectrum. Besides, the energy resolution of APXS is estimated to be about 135 @ 5.9 keV, which demonstrates that it is currently one of the best X-ray spectrometers for planetary exploration in the world.
APXS was firstly powered on December 23, and an in-flight calibration of a standard basalt rock sample mounted on the rover was accomplished in five minutes, which proved its stable performance on the Moon. Two days later, APXS was successfully deployed to about two to three centimeters above the lunar regolith surface by the robotic arm of Yutu and started the detection mode. APXS was not only an X-ray spectrometer, but also served as a distance sensor during the deployment by making use of how X-ray count rate varied with distance.
The Institute of High Energy Physics (IHEP) developed APXS in collaboration with the Purple Mountain Observatory (PMO), CAS. Prior to the APXS on Chang’e-3, two X-ray spectrometers onboard Chang’e-1 and Chang’e-2 developed by IHEP scientists were launched respectively in October 2007 and October 2010.
Contact:
Mr. Xu Tongzhou
IHEP Public Affairs
+86 10-8823-5008
xutz@ihep.ac.cn
http://english.ihep.cas.cn/
CHANG’E-3 SATELLITE PAYLOAD APXS OBTAINED ITS FIRST SPECTRUM OF LUNAR REGOLITH
The Active Particle-induced X-ray Spectrometer (APXS), carried by the Yutu rover of the Chang’e-3 satellite, got its first X-ray fluorescence spectrum of lunar regolith around the landing site on December 25, 2013.
An initial analysis indicates that eight major rock-forming elements (Mg, Al, Si, K, Ca, Ti, Cr and Fe) and at least 3 minor elements (Sr, Y and Zr) of the Moon can be identified in this spectrum. Besides, the energy resolution of APXS is estimated to be about 135 @ 5.9 keV, which demonstrates that it is currently one of the best X-ray spectrometers for planetary exploration in the world.
APXS was firstly powered on December 23, and an in-flight calibration of a standard basalt rock sample mounted on the rover was accomplished in five minutes, which proved its stable performance on the Moon. Two days later, APXS was successfully deployed to about two to three centimeters above the lunar regolith surface by the robotic arm of Yutu and started the detection mode. APXS was not only an X-ray spectrometer, but also served as a distance sensor during the deployment by making use of how X-ray count rate varied with distance.
The Institute of High Energy Physics (IHEP) developed APXS in collaboration with the Purple Mountain Observatory (PMO), CAS. Prior to the APXS on Chang’e-3, two X-ray spectrometers onboard Chang’e-1 and Chang’e-2 developed by IHEP scientists were launched respectively in October 2007 and October 2010.
Contact:
Mr. Xu Tongzhou
IHEP Public Affairs
+86 10-8823-5008
xutz@ihep.ac.cn
Copyright ©2002-2013 Institute of High Energy Physics, CAS
Questions and Comments to webmaster@ihep.ac.cn
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Questions and Comments to webmaster@ihep.ac.cn
mailing address:19B YuquanLu, Shijingshan District
Beijing, 100049 FAX: 86-10-88233374 TEL: 86-10-88233093
------------------------------
Guang Pu Xue Yu Guang Pu Fen Xi. 2013 May;33(5):1360-3.
[Near infrared distance sensing method for Chang'e-3 alpha particle X-ray spectrometer].
[Article in Chinese]
Liang XH, Wu MY, Wang HY, Peng WX, Zhang CM, Cui XZ, Wang JZ, Zhang JY, Yang JW, Fan RR, Gao M, Liu YQ, Zhang F, Dong YF, Guo DY.
Abstract
Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang'E-3 lunar rover, the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present paper will first give a brief introduction to APXS, and then analyze the specific requirements and constraints to realize distance measurement, at last present a new near infrared distance sensing algorithm by using the inflection point of response curve. The theoretical analysis and the experiment results verify the feasibility of this algorithm. Although the theoretical analysis shows that this method is not sensitive to the operating temperature and reflectance of the lunar surface, the solar infrared radiant intensity may make photosensor saturation. The solutions are reducing the gain of device and avoiding direct exposure to sun light.
- PMID:
- 23905352
- [PubMed - in process]
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Guang Pu Xue Yu Guang Pu Fen Xi. 2012 Jul;32(7):1965-8.
[Temperature effect correction for Chang'E-3 alpha particle X-ray spectrometer].
[Article in Chinese]
Wu MY, Wang HY, Peng WX, Zhang CM, Zhang JY, Cui XZ, Liang XH, Wang JZ, Yang JW, Fan RR, Liu YQ, Dong YF, Wu F, Zhao XY.
Abstract
Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang'E-3 lunar rover of China's Lunar Exploration Project. The present paper introduces briefly the components of APXS, how it works and its working environment on the lunar surface. The environmental temperature effect has been studied with simulations and experiments, and the results show that the temperature of the APXS sensor will be varying during the measuring on the lunar surface. And another experiment reveals that the energy resolution becomes worse if the sensor's temperature is varying. In this paper, a correction method based on Pearson's chi-squared test is presented. The method can improve the energy resolution when the sensor's temperature is varying. We have tested the method with the spectra acquired by APXS in the temperature varying period of Temperature Cycling Test, and the results show that the method is efficient and reliable.
- PMID:
- 23016364
- [PubMed - in process]
------------------------------
...
APXS (Alpha Particle X-Ray Spectrometer):
APXS was developed by IHEP (Institute of High Energy Physics) of CAS. The objective is to measure the composition and distribution of various elements on the lunar surface by observing the scattered X-rays from the bombardment of alpha particles on rocks. Located on the rover’s robotic arm, APXS is capable of active particle scattering, in-situ determination of lunar surface elements, in-orbit calibration and distance measurement functions. The sensor can re-calibrate itself through the use of standard calibration targets, and the rover's lunar night survival contains a RHU (Radioisotope Heater Unit) for keeping the sensor warm. It has low energy consumption, low mass, high resolution, and high sensitivity semi-conductor sensors are used.
Figure 17: APXS components (from left to right): sensor head, RHU & calibration target (image credit: CLEP, Ref. 2)
1) “Chang'e 3,” Dragon in Space, URL: http://www.dragoninspace.
2) Patrick Blau, “Chang'e 3 - Mission Overview,” Spaceflight 101, URL:http://www.spaceflight101.
...
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Read more about China's Chang'e 3 mission.
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