Neutron energy spectrum adjustment using deposited metal films on Teflon in the miniature neutron source reactor

• Neutron energy spectrum in the MNSR using DMFTs was experimentally estimated.
• The usability of DMFTs in the measurement of neutron energy spectrum was studied.
• STAY'SL was used for neutron spectrum adjustment (input one calculated by the MCNP).
• Comparison of theoretically calculated and adjusted spectra shows a good agreement.
• DMFTs can be used in the MNSR reactors as thermal and resonance neutron detectors.

The focus of this article was on the experimental estimation of the neutron energy spectrum in the inner irradiation site of the miniature neutron source reactor (MNSR), using, for the first time, a selected set of deposited metal films on Teflon (DMFTs) neutron detectors. Gold, copper, zinc, titanium, aluminum, nickel, silver, and chromium were selected because of the dependence of their neutron cross-sections on neutron energy. Emphasis was placed on the usability of this new type of neutron detectors in the total neutron energy spectrum adjustment. The measured saturation activities per target nucleus values of the DMFTs, and the calculated neutron spectrum in the inner irradiation site using the MCNP-4C code were used as an input for the STAY'SL computer code during the adjustment procedure. The agreement between the numerically calculated and experimentally adjusted spectra results was discussed.