The Chinese Spallation Neutron Source Data Acquisition System Data Formats And Transmission Software Design

China Spallation Neutron Source(CSNS) project required the constructions of three spectrometers. They are General Purpose Powder Diffractometer (GPPD), Small-Angle Neutron Spectrometer (SANS) and Multi-purpose Reflectometer (MR). This thesis work is to design the CSNS spectrometer data acquisition system(DAQ) of the data frame format and data transfer software.The traditional form of neutron scattering data using a histogram to save, However, the histogram will generate a loss of real-time information, while the data fragmentation will introduce errors.In order to improve the quality and according to the neutron hits presented examples to save the original data, Experiment used NeXus standards to achieve the data transmission and storage.According to its own characteristics and needs, CSNS also use NeXus standard as its data processing of the basic specification.This paper studies the various relevant experimental methods,and presents the CSNS data frame format.This format uses an integer bit-field method, to a byte unit as the minimum information processing unit and a plurality of consecutive bytes as a complete description of a case.Data transfer software is a data acquisition system core processing software.It includes sources for generating data,data assembly and data analysis.Because the tasks of CSNS are parallel, the data acquisition system software requires a data source. Data sources generate the random data and sent it to the back-end;Data assembled software receives data while assembling the data, and then send the data to the back-end;Data analysis software to receive data while parsing the data, and then provides a single case analysis, multi-case analysis, and archiving functions.Data frame format and data transfer software design has been completed, the paper also built the appropriate platform to test the design.The results indicates that the data transfer rate, data assembly and parsing algorithms and other auxiliary functions have been designed to meet the basic needs.