The Research On Data Acquisition Circuit Based On FPGA

China Spallatio n Neutron Source (CSNS) is a Large scientific fac ilities which canproduce neutrons through high-energy protons which are provided by the acceleratordevice bombarding heavy meta l target. CSNS can provide such high flux ne utronsource that it provides a powerful research platform invo lving substances in themateria l properties and the microscopic structure and dyna mics of ma ny frontierdisciplines.As an important spectrometer of CSNS, high Inte ns ity powder d iffractometer(HPID) stud ies the crysta l and ma gnetic structure of the materia l by neutron powderdiffraction techniques.3He tube detector,as a part of HPID,can record the time offlight and inc ident position o f the scattering ne utron to obta in the differentwavele ngths o f the inc ident ne utron scattering pattern and understand the structure ofthe sample. the charge measure me nt electronics syste m,as the key part of the3He tubedetector,can calculate out o f the a specific location where the particles hit the3Hetube through data acquisition and processing.This thes is introduces a data acquis ition c ircuit based on FPGA on the backgroundof the charge measureme nt electronics system in the HPID of CSNS. Primarily toamp lify the signal and converts the single-ended signa l to a differentia l signa l afterthe amp lificatio n,filtering and shaping.The n, after using the ADC converts the ana logsigna l to digita l signal, ADC trans mits the digita l signa l to the FPGA for processing.Fina lly, using interna l RocketIO module of FPGA trans fers the signa l to themotherboard for further process ing through the interface between the daughter boardand motherboard.Finish the overall structure of the circuit and the hardware design ofeach module inc luded in the circuitComplete the PCB des ign accord ing to the rule ofthe daughter board and finis h FPGA firmware deve lopmen t whic h can realize thedeseria lizer of the serial data and high-speed seria l trans miss ion o f data using VerilogHDL langua ge in the ISE13.3develop ment environment. Fina lly，comp lete the circ uitdebugging a nd finish the test and analys is of the performance of ADC. The test resultshows that the data acquis ition c ircuit based on FPGA can work properly. TheENOB(Effective Number of Bits) is11.5bit. The INL(Integra l Nonlinearity) is0.29%,which meets the design requirements.