moderation

in nuclear chemistry
https://doi.org/10.1351/goldbook.M03960
Reduction of the neutron energy by scattering without appreciable capture.
Source:
PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1546 (https://doi.org/10.1351/pac198254081533)