A nuclear radiation detector is disclosed. The detector includes a housing including therein: a scintillator; and a multi-pixel optical sensor positioned, relative to the scintillator, to receive photons emitted by the scintillator in response to interactions with nuclear radiation. The housing isolates the scintillator and the multi-pixel optical sensor from external light. The detector includes one or more processors operably connectable to the multi-pixel optical sensor; and one or more data stores coupled to the processors having instructions stored thereon which cause the processors to perform operations. The operations include: responsive to the multi-pixel optical sensor detecting photons emitted by the scintillator, receiving, from the multi-pixel optical sensor, data signals indicating 1) spatial locations of individual pixels that detected the photons and 2) temporal data indicating when the detections occurred; and generating, from the data signals, a spatially and temporally resolved image of radiation incident on the scintillator.