Patent ID: 6222190
Filing Date: 2001-04-24
Classification: G01J,G01N

Abstract:
Photo acoustic (IR) detector comprising a chamber for receiving a gas or gas mixture, a window for allowing pulsed or modulated IR radiation into the chamber, and a pressure sensor adapted to detect or measure pressure changes in the chamber as a consequence of absorbed IR radiation, further comprisinga generally plate-shaped main part having a recess or bore for substantially forming the chamber, whereby the window closes the chamber at one side of the main part, and whereby the pressure sensor is of the miniature type and is located at the opposite side of the main part in relation to said one side, so that the pressure sensor communicates with and closes the chamber at the opposite side, except for a venting channel for the chamber, anda cap provided at said opposite side of the main part so that it encloses the pressure sensor and forms a gas space communicating with the chamber through the venting channel and being substantially larger than the gas volume in the chamber.