The decision to employ high voltage lithium ion beams on the 100 TW PBFA-II accelerator has prompted the investigation of using the inverse nuclear reaction D(7Li, n)8Be as an intense beam diagnostic. The diagnostic scheme operates by utilizing the high energy neutrons that are emitted from the D(7Li, n)8Be reaction when a 7Li beam is incident upon a target containing deuterons. These high energy neutrons can in turn induce the 63Cu(n, 2n)62 Cu(β+) reaction. The amount of 9.74 min 62Cu activity formed can then be measured and related to the total number of 7Li in the beam. The results of calibration runs using 7Li beams accelerated to energies from 1 to 32 MeV are summarized.