The Key Technology Research Of Digital Instrument For Rock Core Scanning

In recent years, geological industry has obtained rapid development in our country. Especially, the application of new technology and new methods promote the improvement of geological research. According to the survey, china has millions of meters task of drilling and products lots of core, which are stocked in the core ware house when they have complied, but the utilization is low, leading to lots of waste of resource. To solve the problem of analyzing and saving the core, a standard core database which contains the information of the core image, the core spectrum,the element content and is provides method for the geological study and prove and analyze the geological information established. The user can visit the databases anytime for searching studying work.The digital core scanners consist of the components such as automatic sample, the control module, the image acquisition module, the spectral collecting module the elements of information collection module etc. Automatic sample machine realizes the location in three dimensions automatically to find the sample's focus and transmit sample. The module of Image collection is designed to gather the image information of the core by using High Definition Camera and to realize the seamless link of images. The module of spectrum collection gains spectrum information of the mineral online.Software module contains two parts-the bottom controlling software and the data processing software, which competing the task of extracting the mineral's information, mineral inversion qualitative and quantitative analysis.(1) The optical part design of wide-spectrum optical fiber & spectrum subsystem. Through the discussion and comparison the method of spectral measurement, the way of spectral measurement based on the reflected mode is determined and light resources are selected reasonably.Through the fiber, so the interface of the light cone and the fiber is designed; Adopted horizontal symmetric optical path, and path callus raster as the spectral components. To get the spectral raster every millimeter scribed line for 177 through theoretical computation and reasonably design of the light path through the theoretical computation and simulation, and it make it preferable prior to tell the 900nm place than to tell the 5nm place the resolution ratio in 2500 nm place get 6nm; Considering that the spectrum of the range from 400 to 2500 nm. The CCD device whose responses in different wavelengths, and propose using three CCD. In order to decrease the loss such as the conjunction the plan we divide the spectrum areas, from 400 to 900 nm from 900nm to 1700 nm, from 1700 to 2500 nm, we adopt the manner connectional of total optical reflection, this method the detectors which is built up on the surface of the three CCD devices, and narrow the volume.(2) Electronics part design of wide spectrum fiber spectrometer subsystem. According to the different spectrum, the CCD detector is selected reasonably. It is S3924-512 detector detect the wavelength range 400-900nm spectrum.And the G9214-512S detect the wavelength range 900-1700nm spectrum.And the G9208 detector detect the wavelength range 1700～2500nm spectrum; Through using the CPLD three CCD driving circuits are designed; According to the design requirements, the ADC circuit with AD9243 as the core is designed, and through the rational wiring and grounded, when the Samples values is at the range of 8196～8199, the fluctuation range will be controlled within±1.5;Because the image data quantity is enormous, so we design the communication system of USB2.0. The USB2.0 communication system which uses CY7C68013 SCM as the core can do the firmware, drivers and applications of programming interface. Finally, the Wide spectrum of fiber optic spectrometer sub-system is tested for validation.(3)Through the analysis and discussion for X-ray source and X-ray detector, fluorescence spectrometer sub-system adopts the micro X ray tube MAGNUM, and the electrical refrigeration Si-PIN detector XR-100CR can realize the elements of qualitative and quantitative analysis. Because of the signal, and dynamic range in order to realize the need of linear amplifier compensation, we design the gain control range from 20 to 1000 time broadband amplifier. Amplifier consists of Low noise JFET tube, differential input structure, and though adopting new pressure controlled amplifiers AD60 to realize gain control, at the same time through the wiring and reasonable compensation, the amplifier gain can achieve 10～1000 continuous adjustable and 5MHz superior, and the linear is good. And design the high ADC circuit with AD9224 as the core, the Sampling rate can reach 20Mbp.(4) The High-voltage power design of X-ray fluorescence spectrometer subsystem. The design adopt VMOS power mosfet as switch components, and adopts separate-excited efficient inverter, the backward stage adopt times pressure rectification, the output of the high voltage power can reach 40KV and 50uA. Corrected technique of active power factor is used to make the input current corrected as the input voltage phase with and really sine wave, and thus it can apply the Power factor to 1 to improve the efficiency of power; the feedback compensation usees the composite compensation mode, also adopts PID algorithm to reach high voltage output.(5) The multi-pulse amplitude analyzer design of X-ray fluorescence spectrometer subsystem. It adopts the top-down brand-new design, and adopt High-speed FPGA device to realize the design of more pulse amplitude parsers to realize the pulse-shaping, baseline restoring, and many other compensator complete the whole digital design; The digital comparator and digital hysteresis comparison are designed and the multi-level buffer water mode is used to realize the pulse amplitude; Lagrange interpolation is adopted to realize the fitting of pulse peak and improve energy resolution in the meantime.As studying and solving the above problem, this paper puts forward some innovational ideas as follow:(1)This article puts forward a entirely new design which adopt the unified technology of the optics, the mechanism, and the electricity to make the on-line examination and storage of the core's image, the spectrum information of the mineral and the element content, combined with the core's feature.It is the first time that the technology of small fluorescence analysis is used to core scanning and realize the automatic scanning of the core. The first prototype of digital scanner for the rock core, whose function contains the image collection and the spectrum collection and the analysis of element contents, has been successfully produced.(2) The stereo link of the light and the three detectors is used to realize the wide spectrum measurement, whose wavelength ranges form 400nm to 2500nm and covers from the visible spectrum to the near-infrared wavelength. Owing to use an all-in-one design of the optical path, the optical fiber transmission and the reflection of the optical path, it can avoid the consumption of the lens's energy and has a strong representative in the measurement. Especially the shortwave near-infrared energy's loss is lesser, it also improve the signal-to-noise ratio of the entire band.(3) The entire digital design realizes the analysis of the multi-pulse amplitude, and avoids processing of the pulse forming, the baseline recovery, and the dead time correction etc. in the stage of the analog signals. The detection of the pulse amplitude adopts the triple interpolation method, which increases the energy resolution ratio in the same ADC sampling rate. FPGA is used to realize the all of analysis of the pulse height, and meet the requirements of the high count-rate measurement. Due to the FPGA which realizes the real-time manage to the pulse, it avoids having the impact that comes form the pulse rate's fluctuation on the result of measurement, and improve the accuracy of analysis of the luminoscope.(4) On the base of the research achievement, the first prototype of digital scanner for the core, whose function contains the image collection of the element information has been successfully trail-produced. By using the scanner of this core, it can measure the core of the drill Z801 in ZI JIN SHAN Mine, and the drill hole 1902 in De Xing Copper Mine practically, and depict the spectrum curve to establish the mineralization module for typical core by analyzing the application of the spectrograph subsystem and X luminoscope.Test results show that the application of core digital scanner in geological prospecting and core digital management field has a good prospect.