为了满足便携式辐射测量仪同时测量X、γ和中子辐射场的需求，设计基于LaBr₃（Ce）晶体、硅酸锂铝（Lithium Aluminum Silicate Oxygen，LASO）型中子探测器、高量程盖革-米勒（Geiger-Muller，GM）计数管的便携式多功能辐射检测仪。对LaBr₃晶体输出的光信号经光电倍增管光电转换后，采用一体化数字多道进行数据采集处理及运算，对中子探测器和GM管计数器分别设计前置信号处理电路，并对其进行放大、甄别、整形等处理。最后将LaBr₃探测器处理的数字信号以TTL（Transistor-Transistor Logic）串口形式传输给ARM（Advanced RISC Machine）处理器，将中子探测器和GM计数管成形后的脉冲信号接入到ARM外部计数端口。ARM对LaBr₃探测器采集的γ数据进行能谱显示、低剂量率测量，对中子探测器、高量程GM管计数器分别进行定时计数，通过计数率换算成剂量率进行显示。该便携式多功能辐射检测仪可实现宽量程γ、低能X射线和中子剂量率的同时测量以及LaBr₃能谱仪的核素识别，并通过USB接口将数据上传到PC端。

Background In order to fast and conveniently measure X, γ and neutron radiation field simultaneously, portable multi-function radiation detector is highly demanded. Purpose This study aims to design a portable multi-function radiation detection system based on LaBr₃(Ce) crystal, lithium aluminum silicate oxygen (LASO) neutron detector and high range Geiger-Muller (GM) counter. Methods After the optical signal output from the LaBr₃ crystal was photoelectrically converted into electronic signal by the photomultiplier tube (PMT), the integrated digital multi-channel was used for data acquisition of electronic signal, and the subsequent data processing and calculation. The front signal processing circuits, such as amplification, discrimination and shaping, were designed for both the LASO neutron detector and the GM tube counter. Finally, the digital signal processed of the LaBr₃ detector was transmitted to the ARM (Advanced RISC Machine) processor in the form of TTL (Transistor-Transistor Logic) serial port, and the pulse signal formed of the neutron detector and GM counter tube was connected to the external counting port of ARM processor. Energy spectrum was processed for nuclide identification and displayed by ARM processor whilst the low dose rate measurement base on the Gamma data collected by the LaBr₃ detector, the neutron detector and the high range GM tube counter were counted at fixed time and converted from the count rate into the dose rate. Results & Conclusions The designed portable multi-function radiation detector realize simultaneous measurement of wide range (48 keV~3.0 MeV) γ, low-energy (48 keV~1.25 MeV) X-ray, (0.1~100 mSv∙h^-1) neutron dose rates, and nuclide identification capability of LaBr₃ spectrometer, and upload the data to PC through USB interface.