TOF-SIMS数据采集系统的研制

发布时间：2018-01-16 11:40

本文关键词：TOF-SIMS数据采集系统的研制　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：飞行时间二次离子质谱(TOF-SIMS)结合了二次离子质谱(SIMS)和飞行时间质量分析器(TOF)的技术特点,是一种无需对样品进行化学处理、对样品近乎无损、分析速度快、质量范围宽、质量分辨率好的表面分析技术。目前TOF-SIMS仪器已广泛应用于生命科学、材料科学、地质学和宇宙科学等领域。数据采集系统是TOF-SIMS仪器的重要组成部分,获取TOF-SIMS离子检测器输出信号时间信息并形成TOF-SIMS质谱图,完成样品质谱分析。根据“同位素地质学专用TOF-SIMS科学仪器”项目对数据采集系统的需求,结合TOF-SIMS仪器特点及离子检测器的信号特征,完成了TOF-SIMS数据采集系统的总体方案设计,并确定了时间测量范围大于340微秒、时间分辨率小于60纳秒、与上位机实际数据传输速度大于200兆字节每秒等性能指标。TOF-SIMS数据采集系统采用时间数字转换技术,硬件部分主要由定时甄别与电平转换模块、时间数字转换模块以及PCIE接口模块构成,通过基于FPGA的控制器为各模块提供控制时序,数据采集系统通过PCIE接口与上位机PCIE总线相连。TOF-SIMS数据采集系统通过定时甄别器获取离子检测器信号的时间信息并输出标准脉冲,利用时间数字转换技术计算出二次离子在飞行时间质量分析器中的飞行时间,通过FPGA控制PCIE接口将离子飞行时间数据传输至上位机。TOF-SIMS数据采集系统的上位机驱动采用WDM驱动模型,在Matlab环境下进行数据处理,并形成横轴为离子飞行时间、纵轴为各飞行时间的离子计数的TOF-SIMS质谱图,质谱图显示于Matlab GUI界面中。通过测试TOF-SIMS数据采集系统的时间测量范围、时间分辨率、数据传输速度等系统性能指标,验证系统满足设计要求。最终将TOF-SIMS数据采集系统应用于同位素地质学专用TOF-SIMS仪器中,通过TOF-SIMS质谱图对锆石样品进行简单的质谱分析。
[Abstract]:Time of flight secondary ion mass spectrometry (TOF-SIMS) combines the technical features of the secondary ion mass spectrometer (SIMS) and the time of flight mass analyzer (TOF). It is a kind of sample without chemical treatment, nearly non-destructive to the sample, fast analysis speed and wide quality range. Surface analysis technology with good quality resolution. At present, TOF-SIMS instrument has been widely used in life science and material science. Data acquisition system is an important part of TOF-SIMS instruments. The TOF-SIMS ion detector outputs signal time information and forms a TOF-SIMS mass spectrogram. Complete the sample mass spectrometry analysis. According to the "Isotope Geology Special TOF-SIMS Scientific instrument" project, the data acquisition system is required. Combined with the characteristics of TOF-SIMS instrument and the signal characteristics of ion detector, the overall scheme design of TOF-SIMS data acquisition system is completed, and the time measurement range is determined to be more than 340 microseconds. The time resolution is less than 60 nanoseconds. The TOF-Sims data acquisition system adopts time-digital conversion technology, and the actual data transmission speed is more than 200 megabytes per second. The hardware is mainly composed of timing discrimination and level conversion module, time-digital conversion module and PCIE interface module, through the controller based on FPGA to provide control timing for each module. The data acquisition system is connected with the host computer PCIE bus through the PCIE interface. The TOF-Sims data acquisition system acquires the time information of the ion detector signal and outputs the standard pulse through the timing discriminator. The time of flight of secondary ions in time-of-flight mass analyzer is calculated by time-digital conversion technique. Through the PCIE interface controlled by FPGA, the ion-time-of-flight data is transmitted to the upper computer. TOF-Sims data acquisition system is driven by the WDM driver model. The data were processed in Matlab environment, and the TOF-SIMS mass spectrogram was formed in which the transverse axis was the ion flight time and the longitudinal axis was the ion count of each time of flight. The mass spectrogram is displayed in the Matlab GUI interface. The time measurement range, time resolution, data transmission speed and other system performance indexes of TOF-SIMS data acquisition system are tested. Finally, the TOF-SIMS data acquisition system is applied to the special TOF-SIMS instrument for isotope geology. Zircon samples were analyzed by TOF-SIMS mass spectrometry.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP274.2

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