Device for determining the concentration of at least one gas component in a breathing gas mixture

A device 1 for determining the concentration of a gas component includes a radiation source 30 for radiating 31 infrared light, two detector arrays 52, 62 with two detector elements 50, 60 configured for detecting the radiated light and two different IR filter elements 51, 61, a gas flow channel 100 with first and second light transmission elements, and a diaphragm element 23. The component spacing is optimised such that the two detector elements are oriented in relation to the radiation source so that a range of overlap (65, Fig 4) is obtained in the flow channel for the emitted light between the two detectors. Attenuations in the propagation of light which may be due to gas molecules or moisture (400) affecting both detector elements are thus compensated in measuring gas concentration.