An NDIR gas sensor takes advantage of a conventional packaging embodiment commonly used to house detectors of all kinds comprising a can, header and a dish sample chamber all welded together to form a single detector unit.

The can forms the top, a hollowed out header body forms the middle and a custom dish sample chamber forms the bottom of a completely functioning NDIR gas sensor. Whereas the header body not only accommodates all the optoelectronic and optical parts on its top surface providing the required signal processing functions for the gas sensor, part of its body is excavated below to accommodate a custom dish sample chamber in communication with the gas outside whose concentration level is to be measured.

A lens and windows are also fabricated on the top part of this header body so that infrared radiation can enter the dish sample chamber below and then be redirected back above for signal processing. To achieve this optical feat, strategic reflecting surfaces are impregnated on the top of the can housing so as to direct infrared radiation to the dish sample chamber below through a lens and then redirect the radiation above via another window for subsequent signal detection and processing.