Abstract: The present invention comprises a gas analysis arrangement (1), comprising a chamber (20) containing a sample of gas (“G”), light-emitting means (3), means (4) for receiving light that has been reflected through the chamber, and an electronic circuit (5) for calculation, adapted such that it is able by means of spectral analysis to analyse and determine the presence of a selected gas or mixture of gases present as a sample (“G”) of gas within the said chamber (20). The said chamber (20) offers one or several apertures for the passage of the sample of gas into and out of the said chamber. The said chamber (20) is assigned a somewhat curved shape, with at least one con-cave curved light-reflecting surface (30b) extending between the said light-emitting means (3) and the said light-receiving means (4).