基于FPGA的虚拟放射源系统

Virtual radiation source system based on FPGA

核物理实验、放射医学等领域都离不开放射源及其探测。利用DAC、FPGA以及直接数字合成技术构建虚拟放射源系统,能够灵活选择放射源和探测器的种类,也能设置放射源与探测器的相对距离和角度。根据某种放射源的实验谱线按照一定的频率发射幅度信号,通过网口传输进入FPGA数字处理平台。FPGA接收幅度信号并进行处理,从而得到具有特定探测器特征的脉冲信号。采用14位数模转换芯片LTC1667将FPGA得到的数字信号转化为模拟信号。使用脉冲幅度分析仪对该脉冲信号进行采集和分析,并通过相应软件获得能谱。结果表明,虚拟化的放射源代替实物放射源和探测器不仅可以达到相似的效果,而且更加具有灵活性、方便性和安全性。

Nuclear physics experiments,radiation medicine and other fields are inseparable from the radiation source and its detection.By using DAC,FPGA and direct digital synthesis(DDS)technology to build a virtual radiation source system,the types of radiation source and detector can be flexibly selected,and the relative distance and angle between radiation source and detector can be set.According to the experimental spectral line,the amplitude signal is transmitted at a certain frequency,and it enters the FPGA digital processing platform through the network port.FPGA receives the amplitude signal and processes it to get the pulse signal with specific detector characteristics.The 14 bit digital-to-analog conversion chip LTC1667 is used to convert the digital signal from FPGA to analog signal.Pulse amplitude analyzer is used to collect and analyze the pulse signal and obtain the energty spectrum through the corresponding software.The results show that the virtual radiation source can not only achieve the similar effect,but also have more flexibiliy,convenience and safe.