Abstract: A detector assembly includes an elongate structure and a scintillation detector. The elongate structure defines a detector cavity having an axial dimension extending along a longitudinal axis. The scintillation detector is disposed at least partially within the detector cavity. The detector system can also include a cabinet which can be coupled with an end of the elongate structure, and which can define a cabinet cavity for retaining a junction board, a display screen, a microprocessor unit, and/or other components. The detector assembly can have an explosion-proof rating. A detector system including the detector assembly and a detector unit is also provided, such as for use in applications requiring an explosion-proof rating.