Since the launch of the first X-ray focusing telescope in 1963, the development of grazing incidence X-ray optics has been crucial to the development of the field of X-ray astronomy. The recent Decadal Survey also highlights the important contribution that X-ray astronomy can make in addressing some of the most pressing scientific questions about black holes, cosmology and the ebb and flow of energy and matter in the evolving universe, and recognizes the research needed to mature the key enabling technology of X-ray optics. The proposed development directly addresses this need by providing a unique detector designed specifically to support the development of the next generation of X-ray telescopes, which will allow researchers and engineers to characterize such X-ray telescopes with high accuracy, and thereby optimize their performance and best utilize their gathered data. By the end of the Phase I/Phase II program we will have developed a fully calibrated detector ready for use at various facilities, including NASA's Marshall Space Flight Center and other NASA-funded research centers such as the Harvard Smithsonian Center for Astrophysics and Columbia University. The estimated technology readiness levels (TRLs) at the beginning and end of the Phase I contract are 4 and 5, respectively.