| Papers from the National 863 Plan the resources and environment issues "survey of airborne gamma-spectrometry system research and development (No. 2006AA06A207)" as well as the National Natural Science Foundation project "natural gamma nuclear geophysics market research (No. 40774063)".Airborne gamma-ray spectrometry is a gamma-ray spectrometer will be loaded on the plane to obtain gamma-ray exposure rate and a method of geophysical exploration aviation, has been widely applied to investigate the mineral resources, environmental investigation and evaluation of radiation . Monte Carlo simulation of airborne gamma-ray spectrometry equipment spectrum, not only for spectral gamma detector probe provides a new calibration method; and gamma radiation for different body shapes, different altitude conditions, such as measurement The characteristics of aerial gamma spectroscopy equipment to provide a scientific reference; the actual airborne gamma-ray spectrometry has played a guiding role and qualitative analysis, but also provides a theoretical basis.Paper discusses the nature of the sources of naturalγ-radiation, to - the air-ground interface on the distribution ofγ-ray spectrum of natural features andγ-photon mechanism of interaction with the material; the establishment of a numerical simulation based on Monte Carlo simulation model of a random sample; in this based on their own using C + + language developed a Monte Carlo simulation softwareγ-ray spectrum. Produced its own software applications, content has been set on the natural strata of the media (which contai?? 170g/kg, U 0.003g/kg, Tl 0.01g/kg) drawn up from an analysis of radionuclides CPC 17 kinds of natural radioactive energyγ-rays penetrate the media after a number of high air into the NaI (Tl) crystals in the simulated response. Simulation of the process of research and main achievements are:1) the natural environment of the mainγ-ray radiation in the body drawn up from an analysis of specific radionuclides (such as: 214Pb, 214Bi, 223Ac, 208Tl, 40K, etc.) and a total of 17 kinds of the correspondingγ-ray energy, and calculated the nuclear Su-balance in conditions of radioactive relative content, as well as the content of the corresponding field of the naturalγ-ray contribution to the value and relative risk of radiation;2) the establishment of a uniform surface radionuclide media type, the location of radioactive nuclides,γ-photon initial direction of the shooting,γ-photon with the medium type, and collision response, such as random sampling from the model, the aviation spectrum ofγ-ray spectrometry equipment Monte Carlo simulation provides a theoretical formula;3) building a virtual detector model, the virtual probe to change its own structure, geometry and size, enlarge the actual size of the virtual detector geometry, the use of virtual detector probe and the actual size of the ratio between the coefficient of probe when receiving the location ofγ-photon conversion, which improve the sampling efficiency and variance reduction of Monte Carlo simulation;4) According to the gamma photon in geological media, the air medium and the detector in the transport process, the preparation of the aviation spectrum of gamma-ray spectrometry equipment Monte Carlo simulation software, which has the sampling frequency, detector size, simulating a high degree of adjustable and display features such asγenergy spectrum, showing a better effe???) through the simulation of different height to theγ-ray spectrum analysis of airborne gamma-ray spectrometry in altitude of the detector plane and the curve, indicating a high degree of spectral area with peak area counts and all counts were as decreasing function of index.
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