1. A spectroscopy analysis method comprising: obtaining output data from at least one photon detection device; step for calculating, with a processing device, a gamma-gamma coincidence summing correction factor and an X-ray coincidence summing correction factor for multiple coincident gamma and X-ray detections; applying the X-ray coincidence summing correction factor to the gamma-gamma coincidence summing correction factor to generate corrected full energy peak measurement data; and transforming the corrected full energy peak measurement data to a visual representation for presentation on a display device for operator review.