Development Of Readout Electronics For Oblique Incident Neutron Scintillator Detector

China Spallation Neutron Source(CSNS)is a large-scale scientific installation built in China during the 11 th Five-Year Plan period,providing an advanced and powerful scientific platform for the research of physics,life science and new energy in China.Engineering Material Neutron Diffractometer is one of the cooperative spectrometers under construction.It has the functions of strain,stress and Bragg edge projection imaging,and can systematically study the information of material microstructure and macroscopic stress during the service of engineering materials and components.Engineering Material Neutron Diffractometer uses an oblique incident neutron scintillator detector as the main detector.The neutrons are incident to the oblique incident neutron scintillation detector,and the neutrons interact with the scintillation screen to generate scintillation photons,which are then collected by waveshifted fiber and transmitted to Silicon Photomultiplier(Si PM),and finally processed by readout electronics.This paper introduces the readout electronics system of oblique incident neutron scintillator detector.The electronics system consists of two parts.The first part is the preprocessing board,which amplifies,filters and discriminates the weak electrical signal output by Si PM,and then outputs the trigger signal.The second part is the data acquisition board,which uses the Field Programmable Gate Array(FPGA)as the acquisition and data processing core to obtain the neutron hit position and time information,and then transmits the position and time information to the upper computer through the Gigabit Ethernet for data analysis and online display processing.The firmware program implements the configuration and data transfer of the electronics.The configuration functions include: the threshold configuration of the discrimination circuit,the configuration of the power supply voltage of the Si PM line and column,and the configuration of the analog-to-digital conversion chip in the voltage and current detection circuit.The data transmission realizes that the collected neutron hitting position and flight time information are packaged according to the periodic proton targeting signal(T0),packaged according to the set data format,and then processed and cached,and then sent to the backend through the Gigabit Ethernet.The configuration function is realized by the three-way handshake UDP protocol,and the data transmission is realized by the mature TCP/IP protocol.After the system design was completed,the corresponding function and performance tests were carried out in laboratory and neutron beam line respectively.The test results show that the performance of the electronic system meets the design objectives.