Abstract: Quasi-monoenergetic reference neutron beams in the energy above 20 MeV have to be produced to satisfied the calibration for the response of the neutron detectors for the neutron field with high energy. The current status of the quasi-monoenergetic neutron reference fields in the energy range from 20 MeV to 400 MeV and the way how they were established were survyed on and reported in this paper, the reaction 7Li(p, n)7Be can be used as the quasi-monoenergetic neutron source in this energy range, the neutron beam profile can be measured with converter and imaging plate, the energy spectrum can be measured with organic liquid scintillation detector or the 238U fission chamber by TOF method, and the proton recoil telescope can be established as the primary instrument in this range.

Key words: Neutron reference field, Neutron spectrometry, Neutron fluence, Accelerator facility