[en] The goal of the Heavy-Section Steel Irradiation (HSSI) Program Sixth Irradiation Series is to determine the effect of irradiation on the shape and shift of the crack-arrest toughness versus temperature curve. Two capsules which contained crack-arrest and Charpy V-notch test specimens have been irradiated at the Oak Ridge Research Reactor located at the Oak Ridge National Laboratory. these capsules have been disassembled, internal dosimeters have been analyzed, and exposure parameters are presented for each irradiation test specimen. This report describes the computational methodology for the least-squares presents exposure parameters at each test specimen location for the fluence rate greater than 1.0 MeV, fluence rate greater than 0.1 MeV, and displacements per atom. The specific activity of each dosimeter at the end of irradiation is listed in the Appendix. 10 refs., 8 figs., 4 tabs