Nuclear security detection is a multifaceted research domain and applied methodology dedicated to the identification and characterization of nuclear and other radioactive materials. It encompasses the study, development, and deployment of technical systems and analytical techniques designed to prevent the illicit trafficking, unauthorized use, or diversion of such materials. This field investigates principles of radiation physics, detector technologies, signal processing, and system integration, emphasizing robust and reliable detection capabilities across diverse operational environments. Its significance is paramount in contributing to global nuclear security frameworks, counter-proliferation initiatives, and the physical protection of nuclear assets.