Extremely high dose neutron dosimetry using CR-39 and atomic force microscopy

Atomic force microscopy (AFM) has been applied to the analysis of CR-39 nuclear track detectors for high dose neutron dosimetry. As a feasible study to extract the neutron dose, we have employed a 239 Pu-Be neutron source with the traditional track density measurement of recoil proton etch pits from a high density polyethylene (CH 2 ) radiator. After very short etching (∼1 μm), etch pit densities were measured as a function of neutron fluence (neutron dose) up to 1.4 x 10 10 cm -2 (6.6 Sv). Neutron sensitivity was also measured to be 6.6 x 10 -4 . Maximum measurable neutron dose was estimated to be ∼200 Sv by measuring the fraction of the total image area occupied by the etch pits.