A method for constructing cavity detectors is presented. The design an
d working principle of a photoacoustic detector is discussed. Methods
of calculating the absorptance of cavities are summarized, and a proce
dure for calculating the absorptance for the chamber of a photoacousti
c detector is given. The spectral characteristics of coatings and the
dependence of the absorptance on different parameters are reported. Th
e characteristics of the detector are compared with those of similar d
evices.