The neutron energy spectrum and fluence of the Atmospheric Neutron Irradiation Spectrometer at China Spallation Neutron Source cover the energy range from meV to GeV. The evaluation of the neutron energy spectrum and fluence in the energy region above 1 MeV is of great significance for conducting single event effect studies of atmospheric neutrons. Limited by the proton beam time structure of the CSNS and the engineering realities of the ANIS, it is impossible to obtain the neutron energy spectrum and fluence above 1 MeV through absolute measurements. Therefore, it is necessary to rely on a combination of theoretical simulations and partial experiments to provide reference values. This paper presents the following work: (1)Based on the measured neutron energy spectrum data from the ICE beamline at LANSCE WNR, the physical models, tally types, and cross-section data files suitable for the calculation of high energy neutron energy spectra and fluence were explored using MCNPX2.5.0；（2）A secondary source with energy distribution, angular distribution, and spatial distribution for neutron energy spectrum and fluence evaluation was developed and verified; (3)Based on the obtained neutron energy spectrum and fluence, the performance of the ANIS facility was evaluated from the perspectives of spectrum shape and radiation effect, in combination with existing similar facilities and the JSED89A reference neutron energy spectrum;(4) Conducted an experiment on neutron induced single-event upset cross-section measurement of configuration memory on Xilinx 2nd generation FPGAs using the ANIS. The results are consistent with tests of the same chip series at similar international facilities.In summary, it was concluded that the ANIS at CSNS may be the facility with the neutron energy spectrum closest to the natural atmospheric neutron energy spectrum among similar facilities in the world,and it has also been confirmed that the test results of ANIS at CSNS show excellent consistency with results obtained at other facilities. Therefore, the research results on atmospheric neutron single-particle effects and engineering acceleration tests based on ANIS at CSNS can be directly applied to high-reliability fields such as aviation, aerospace, military, and civil, contributing to the development of new quality productive forces.
Hu et al. (Wed,) studied this question.