[The X-Ray Fluorescence Spectrometer Based on Pyroelectric Effect].

Pyroelectric X-ray generator is implemented, and an X-ray fluorescence spectrometer is accomplished by combining the pyroelectric X-ray generator with a high energy resolution silicon drift detector. Firstly, the parameters of the X-ray generator are decided by analyzing and calculating the influence of the thickness of the pyroelectriccrystal and the thickness of the target on emitted X-ray. Secondly, the emitted X-ray is measured. The energy of emitted X-ray is from 1 to 27 keV, containing the characteristic X-ray of Cu and Ta, and the max counting rate is more than 3 000 per second. The measurement also proves that the detector of the spectrometer has a high energy resolution which the FWMH is 210 eV at 8. 05 keV. Lastly, samples of Fe, Ti, Cr and high-Ti basalt are analyzed using the spectrometer, and the results are agreed with the elements of the samples. It shows that the spectrometer consisting of a pyroelectric X-ray generator and a silicon drift detector is effective for element analysis. Additionally, because each part of the spectrometer has a small volume, it can be easily modified to a portable one which is suitable for non-destructive, on-site and quick element analysis.

[Near infrared distance sensing method for Chang'e-3 alpha particle X-ray spectrometer].

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.

[Temperature effect correction for Chang'E-3 alpha particle X-ray spectrometer].

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.

[Application of direct demodulation technique in analysis of ground verification test of x-ray spectrometer for Chang'e mission].

An X-ray fluorescence imaging spectrometer based on silicon PIN photodiodes was designed and constructed for the Chang'E mission, the first lunar spacecraft, and will be in operation at a 200 km circular lunar orbit with one year lifetime. The X-ray fluorescence spectrometer consists of two silicon PIN photodiodes modules, each holds two low energy detector units to analyze the distribution of useful elements and to estimate the abundance on the moon, which is one of the objectives of the X-ray fluorescence spectrometer experiment. The low energy detector unit is 25 mm2, 500 microm thick, with the energy band of 1-10 keV, and energy resolution of: approximately 5% at 5.9 keV. The ground verification tests of the X-ray spectrometer for Chang' E mission were introduced in the present paper. Taking the energy response matrix of the spectrometer as the foundation and using the direct demodulation technique and fundamental parameter method, the authors performed some quantitative and qualitative analysis of these scientific data which came from the ground verification tests, especially for Mg, Al and Si elements.