Quasi-monoenergetic high-energy neutron standards above 20???MeV

This paper provides an overview of high-energy quasi-monoenergetic neutron sources and facilities above 20 MeV around the world. Various technical matters are discussed which are required in characterizing the neutron fields by spectrometry, fluence and beam profile measurements. Important topics regarding the calibration of neutron detectors are also introduced with emphasis on beam monitoring, tail correction, background subtraction and fluence-to-dose conversion. Efforts to standardize the high-energy neutron fluence in Japan and by the German national metrology institute in collaboration with Belgian and South African institutions are also presented.