The Development Of Portable Digital ? Spectrometer Based On ?C/OS-?

With the constant improvement of electronic technology and computer technology, the trend of portable y spectrometer is going digital. Accompanied by the appearance of more excellent MCU, it provided the conditions for using embedded real time operating system (RTOS) in portable y spectrometer system development. Portable digital y spectrometer is a combination of embedded system and algorithm, a main control board is designed, and portable y spectrometer hardware platform is built with FPGA+dual-MCU, based on the digital multi-channel board that we already have. On this basis, multi-task y spectrometer system software is programmed with the embedded RTOS ?C/OS-?.Firstly, the digital nuclear signal that filtered and shaped from trapezoid (triangle) algorithm is studied, a pile-up pulse identification method, which can maintain the energy resolution and at the same time improve the count rate, is proposed, it is conducive for the usage of y spectrometer in high radioactive occasion.Secondly, y ray equipment spectrum analytical algorithm is designed in this paper. Centroid method is applied to smooth y spectrometry data. The symmetric zero-area conversion method is applied to search peaks and identify overlap-peaks. When subtracting the background, SNIP(Sensitive Nonlinear Iterative Peak Algorithms) method is used. The Gaussian function fitting method is studied in this paper, as a result, this method is strongly to noise sensitivity, so we improve it, that, a weighted factor is introduced, and a weighted Gaussian function fitting method is proposed, which can decrease the influence of the noise. The method about separation and fitting of overlapping peak is also presented, and as a result, we use Gauss-Newton curve fitting method, which has a high speed iteration and small calculating amount.Then, in the hardware aspect, a main control board which is connected with digital multi-channel board is designed based on 32-bit MCU STM32F103ZET6.On the one hand, the main control board is used to control digital multi-channel board to sample nuclear signal, thus obtain y ray equipment spectrum, on the other hand, it provided the conditions for system software.Finally, ?C/OS-III is transplanted into STM32F103ZET6, and on this basis, y spectrometer system software is programed. The software framework is designed into three layers, i.e., user interface layer, software functional layer and ? spectrum analytical algorithm layer. In the realization of the system software, software functional layer is designed into six tasks, and user interface layer and y spectrum analytical algorithm layer are designed into a functional library, respectively. Software functional layer can call these two functional libraries when it is necessary. The application of ?C/OS-? increases the stability of system software, task operation and manage is also convenient. It also exploits the performance of STM32F103ZET6 fully.After the whole design is completed, counting rate test, peak searching test, nuclide identification test and system stability test are carried out. Results show, the design achieves the exceptive goal.