PHOTO ACOUSTIC SAMPLE DETECTOR WITH LIGHT GUIDE

摘要

A photo acoustic sample detector (10) is provided for detecting a concentration of sample molecules in a sample mixture (1). The photo acoustic sample detector (10) comprises an input for receiving the sample mixture (1), an acoustic cavity (3) for containing the sample mixture (1), a light source (5) for sending light (50) into the acoustic cavity (3) for exciting the sample molecules and thereby causing sound waves in the acoustic cavity (3) and a pick up element (4) for converting the sound waves into electrical signals (12). The photo acoustic sample detector (10) also comprises a light guide (2) comprising a transparent inner wall (8) at an interface of the light guide (2) and the acoustic cavity (3) and a reflective outer wall (7) at an outside of the light guide (2). The light source (5) is arranged for illuminating the light guide (2). The light guide (2) serves for reflecting the light (50) back and forth through the light guide (2) and the acoustic cavity (3).