The Study Of γ Energy Spectrum Response Law In Airborne Gamma-ray Spectrometry

Aeronautical gamma spectrometry detection technology is used to measure the natural gamma radiation produced by radioactive isotopes within a certain range of near-surface. According to the IAEA recommendations, usually 256 or 512 spectral are used to sample, and grouped into four standard energy windows: potassium, uranium, thorium and total counts. Potassium is directly measured through 1.46MeVγ-radiation, while uranium and thorium are indirectly measured through theirγradiation in decay series.The height and pitch of the measurement determine the spatial resolution and spectrum resolution that the detector can achieve. Pitch control the vertical side-line sampling density, the track of single measurement increased with the altitude, while the count level decreased with the altitude. Generally, by calculating the area of a single measurement and ensuring the sampling of the area between survey lines, the height and pitch were matched. If the aircraft speed was ignored, meanwhile, assuming the sensitivity of detectors on the gamma ray were the same, the track can be calculated by mathematical models, while the rectangular shape of the modern detectors will lead to significant differences in detector sensitivity, but also depends on the gamma-ray incident angle.Domestically, since the eighties of last century, the research and development work of aviationγenergy spectrum has been stagnated, there is a big gap comparing with the world's technologically advanced countries, the hardware and software of aviationγ-ray spectrometry system depend on importing seriously.In recent years, two kinds of aero geophysical measurement system were introduced, digested and absorbed successfully, based on this, the development and integration of the appropriate hardware and software were completed, the actual production capacity was formed, and the measurement and interpretation technology have got international advanced level; GR-820 air multi-channel gamma spectrometer was successful introduced, digested and experimental produced, which now play an important role in land resources geological survey.Along with the rapid industrialization of nuclear technology development and accelerated construction of nuclear power, the government's relevant departments have also carried out a series of programs and practices to deal with all kinds of variable conditions. Under the leadership of the relevant departments, Shijiazhuang remote testing center established a national nuclear emergency center, and did a series of exercises work, these rules and regulations are ought to response to the challenge occurring in the future development. gamma spectrometry survey system, due to its characteristics, as the main monitoring nuclear emergency measures, is one of the country much-needed high-tech.Specific study has three aspects: first, in certain circumstances, conduct an aeronautical gamma spectrometry detector response test, use the experimental data for spectrum analysis; second, use Monte Carlo to simulated analysis the performance of the aeronautical gamma spectrometer with the experimental data, and compare with the aeronautical gamma ray spectrometry specifications to provide the appropriate theoretical basis for perfecting the instrument. Third, use Monte Carlo to simulated analysis the performance of the angle responses of aeronautical gamma spectrometer with the experimental data, and compare with the experimental result to conclude.This topic comes from "863" major project "Air geophysical survey systems"(Major Project No. 2006AA06A200), mainly aimed the responsibility discipline of the entire aviation spectroscopy, analyze the performance of the instrument even better, There is a profound significance on the studies of theory and practical line, it provides a theoretical basis for the aeronautical gamma ray spectrometry measurement and mineral resources survey.The paper combined Monte Carlo and the experimental data to compare and analysis from the needs of the system, analysis the performance of the instrument better and more accurate theoretically, the next step for the study of theoretical and practical line, to improve aviation gamma EDS system stability and accuracy were based, the accuracy of the results spectrum aeronautical spectrometry exploration system was ensured.