An analysis apparatus includes a gas chamber for receiving a gas to be analyzed, a source to emit radiation into the chamber. The radiation is to selectively excite molecules of the gas. The apparatus further includes a sensor to detect a physical variable which contains information about a degree of interaction between the radiation and the gas. The source includes a heatable planar radiation element to emit radiation and a housing with a first wall and a second wall which, therebetween, define and immediately delimit a radiation element receptacle chamber that is separated in a fluid-tight manner from the surroundings of the source. At least one of the first or second housing wall is transparent to the electromagnetic radiation that is emittable by the radiation element.