Establishment of Monoenergetic Neutron Reference Radiation Fields From 0.144 to 1.2 MeV

The monoenergetic neutron reference radiation fields of 0.144,0.250,0.565 and 1.2 MeV are established at the Division of Radiation Metrology of China Institute of Atomic Energy using a 2×1.7 MV tandem accelerator. The neutron is produced by the ⁷Li(p,n)⁷Be and ³H(p,n)³He reactions. The neutron fluence spectra are calculated with the TARGET code. A recoil proton proportional counter, which can be refilled repetitively, is designed for measuring the neutron fluence of the above energies absolutely. The combined standard uncertainties of measurement are not more than 2.0%. We participated in an international comparison of monoenergetic fast neutron fluence measurements organized by the section Ⅲ of the Consultative Committee for Ionizing Radiation in 2001, and obtained the satisfied results.