Study On Readout Of Thermal Neutron Position-sensitive Detector

Neutron is a good bombardment particle in the study of nuclear reaction,it's not charged,so could cause nuclear reaction with the very low energy.It also plays an important role in nuclear fission reaction.Neutron could be detected only by the secondary effect of nuclear reaction andcan't be directly detected.The interaction section of neutron reaction with materials is inversely proportional to neutron's momentum,so thermal neutron with lower energy has become an important tool for development of new materials research and scientific research.With new generation of neutron sources having been built all over the world,the research topic of large area thermal neutron position sensitive detector has become very important.This paper introduced a design scheme based on thermal neutron position sensitive detector THGEM.The principle of THGEM of neutron detection is based on nuclear reaction 10B(n,a)7Li,taking 10B as the solid target material and detecting the secondary charged particle 7Li and alpha.Collection board,designed based on the method of pads array readout,can realize electroncollection.The neutron position information could be obtained by barycenter readout method.Eachof the two dimensional readout board contained a 64 channels charge signal readout system.In order to simplify the design,a piece of pre-amplifier ASIC(VA64TA2)was used in each direction.64 channels charge signals for each direction could be read serially by ASIC and converted to analog voltage signals.Data acquisition board used 12 bits ADC converter(high speed analog to digital converter AD9220)for analog-to-digital converting.The binary datauploadedthrough the USB2.0 interface connected to the computer.Computer processing program,written by LAB VIEW,realized the real-time data processing and displaying.The FPGA was used as the main controller of the data acquisition system.As to FPGA chip,the second generation Altera's Hurricane series chip,namely Cyclonell EP2C8Q208C8N was chosed.The main function of FPGA were providing the control logic for ASIC(VA64TA2)and ADC(AD9220),realizing ADC connected to USB,buffering digital cdata.In acddition,this paper also introduced the software part of the readout system and related experiment.