Figure 2: Variation with neutron energy and location in the phantom of the relative contribution of secondary charged species to the total neutron dose.
From: The origin of neutron biological effectiveness as a function of energy

Relative contributions of secondary charged species to the total neutron dose as a function of neutron initial energy: (a) inner; (b) intermediate; (c) outer scoring region. Error bars are standard deviations among results for batches in a single run as given by PHITS. Lines are drawn to guide the eye.