The use of the U(n,f) reaction dosimetry in the determination of the λf value through fission-track techniques

A new set of determinations of the decay constant for spontaneous fission of 238U, λf, using mica–uranium sandwich and thin films of natural uranium is presented. A value of λf=(8.37±0.17)×10−17 a−1 has been determined. The use of uranium-based neutron dosimetry for the measurement of λf through fission-track techniques is discussed. Particularly, the λf measurement by Roberts et al. (Phys. Rev. 174 (1968) 4847), is analyzed, showing that the value obtained by these authors (7.03×10−17 a−1) underestimated λf. It is concluded that the dosimetry based on U(n,f) reaction does not support a λf value around 7×10−17 a−1 determined by various authors using mica–uranium sandwich.