【作者】 郑宝华；

【导师】 程德福；

【作者基本信息】 吉林大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 近年来,我国地质事业得到了长足发展,尤其是新技术新方法的应用推动了地质科研的进步。据调查,我国每年有上百万米的钻孔任务,产生大量岩芯,这些岩芯在编录后存入岩芯库房,利用率很低,造成大量的资源浪费。为了对岩芯进行分析和解决岩芯保存问题,对岩芯进行数字化扫描,将岩芯图像、岩芯光谱和元素含量等矿物数据和参数存储在计算机里,建成标准岩芯数据库,使用者可随时访问数据库进行地质信息分析,为地质研究和地质找矿提供便捷的方法。数字化岩芯扫描仪由自动样品控制台模块、图像采集模块、光谱采集模块、元素信息采集模块、软件模块、结构工艺模块等组成。自动样品台实现三维定点,样品自动对焦和自动传送；图像采集利用高清相机,采集岩芯的图像信息,并实现图像无缝拼接；光谱采集模块实现矿物的光谱信息在线采集；元素信息采集模块实现元素的在线检测；软件模块分为底层控制软件和数据处理软件,实现矿物信息提取,矿物数据反演、定性和定量分析等。本文研究所完成的工作如下：(1)宽谱段光纤光谱仪子系统的光学设计。通过对光谱测量方法的讨论和比较,确定了基于反射模式进行光谱测量的方法,合理地选择了光源；通过光纤将漫反射光导入单色器,设计了光锥与光纤的接口；光路采用水平对称光路,全息平面光栅作为分光元件,通过理论计算得到光栅每毫米刻线为177条,通过理论计算和仿真合理地设计了光路,并实现900nm处分辨率优于5nm,在2500nm处分辨率达到了6nm；考虑到目前单个CCD器件不能覆盖400～2500nm宽谱段,采用多块响应在不同波段的CCD器件,提出利用三个CCD传感器拼接成400nm-2500nm波长范围的宽谱段光谱测量方法；为了减少像平面拼接时的能量损失,将光谱面分为三个光谱区域：400～900nm、900～1700nm、1700～2500nm,采用了全反射光学拼接方式,将三个波段的反射光反射到分别布置在三个面上的CCD探测器,缩小了体积。(2)宽谱段光纤光谱仪子系统的电子学设计。根据不同的谱段合理地选择了CCD探测器,即探测器S3924-512Q探测波长范围400～900nm谱段,探测器G9214-512S探测波长范围900～1700nm谱段,探测器G9208-256W探测波长范围1700～2500nm谱段；采用CPLD设计了三个CCD的驱动电路；根据设计指标要求,设计了以AD9243为核心的ADC电路,通过合理布线和接地,采样值在8196～8199范围内时波动范围在±1.5位以内；由于图像的数据量庞大,设计了USB2.0的通讯系统,USB2.0通讯系统是以CY7C68013单片机为核心,进行了固件、驱动和应用程序接口的编程。最后对宽谱段光纤光谱仪子系统进行了测试。(3)通过对X射线光源和X射线探测器的分析和探讨,荧光仪子系统采用了微型X射线管MAGNUM,电制冷的Si-PIN探测器XR-100CR实现元素的定性和半定量测量；由于信号的动态范围大,同时为了实现放大器线性补偿的需要,设计了增益调节范围应为20到1000倍的宽带放大器,放大器采用低噪声JFET管,差动式结构输入,采用新型压控放大器AD603实现增益调节,通过合理的布线和补偿,放大器的增益实现20～1000连续可调、带宽优于5MHz、线性良好；设计了以AD9224模数转换器为核心的高速ADC电路,采样速率达到20Mbps。(4)X射线荧光仪子系统的高压电源设计。设计了采用VMOS功率场效应管作为开关元件,采用它激式高效逆变器,后级采用倍压整流,输出40KV、50 uA的高压电源；采用有源功率因数校正技术,将输入电流校正成为与输入电压同相位且不失真的正弦波,从而使功率因数接近1,提高了电源的效率；反馈补偿采用复合补偿方式,同时采用PID算法,达到高稳定电压输出。(5)X射线荧光仪子系统的多道脉冲幅度分析器设计。采用自顶向下的全新的设计思路,采用高速FPGA器件实现多道脉冲幅度分析器的设计,实现了脉冲成形、基线恢复、修正补偿等全数字化设计；设计了数字比较器、数字滞回比较器,采用多级缓存的流水模式实现脉冲幅度的提取；采用拉格朗日插值实现脉冲峰值的拟合,提高了能量分辨率。在研究和解决以上问题时,本文所提出的创新点如下：(1)本文提出采用光、机、电一体化技术,结合岩芯特点,对岩芯图像、矿物光谱信息和元素含量进行在线检测并数字化的全新设计思路。首次实现了将小荧光分析技术与岩芯扫描相结合,实现岩芯扫描的自动化。成功研制了我国第一台集图像采集、光谱采集、元素含量分析的全数字化岩芯扫描仪样机。(2)采用一套光路和三个探测器立体拼接实现波长范围为400nm-2500nm的宽谱段测量,这一谱段涵盖了可见光到近红外波长。由于采用一套光路、光纤传输及全反射光路设计,避免了透镜能量消耗,测量代表性强。特别是短波近红外能量损失较小,提高了整个波段的信噪比。(3)多道脉冲幅度分析实现全数字化设计,免除了在模拟信号阶段对脉冲的成形、基线恢复、死时间修正等的处理。脉冲幅度检测采用了二次插值方法,使在相同的ADC采样速率下提高了能量的分辨率,脉冲幅度分析全部由FPGA来实现,满足了高计数率测量要求。由于FPGA实现了对脉冲的实时处理,避免了由于脉冲速率波动对测量所带来的影响,提高了荧光仪的分析精度。在本文的研究成果基础上,成功试制出我国第一台集图像采集、光谱分析及元素信息采集于一体的数字化岩芯扫描仪样机。利用该岩芯扫描仪针对紫金山矿区钻孔ZK801的岩芯和德兴铜矿钻孔1902的岩芯进行实际扫描测试,重点分析了光谱仪子系统和X荧光仪子系统的应用情况,绘制了典型矿物的光谱曲线,建立了典型矿物的成矿模型。实测结果表明,数字化岩芯扫描仪在地质找矿和岩芯数字化管理领域具有较好的应用前景。更多还原

【Abstract】 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.更多还原