CPC G01N 29/2418 (2013.01) [G01N 29/02 (2013.01); G01N 33/49 (2013.01)] | 10 Claims |
1. A photoacoustic detecting device, intended to be applied, via a contact face, against a medium to be analysed, the device comprising:
a hollow cavity that emerges onto a first aperture, the first aperture being produced in the contact face;
a pulsed or amplitude-modulated light source configured to emit, in an emission spectral band, an incident light wave, through the cavity, to the first aperture;
an acoustic transducer linked to the cavity and configured to detect a photoacoustic wave extending through the cavity;
such that, under the effect of illumination of the medium, by the incident light wave, the acoustic transducer detects an acoustic wave produced by heating of the medium;
wherein:
the volume of the cavity is smaller than 50 μL;
the device comprises an open tube extending between the cavity and air lying outside the cavity, over a length and a diameter, the length of the tube being comprised between 1 and 20 mm, the diameter of the tube being such that:
when the volume of the cavity is smaller than or equal to 15 μL, the diameter of the tube is comprised between 150 μm and 300 μm;
when the volume of the cavity is comprised between 15 μL and 30 μL, the diameter of the tube is comprised between 200 μm and 350 μm;
when the volume of the cavity is larger than 30 μL, the diameter of the tube is comprised between 250 μm and 500 μm.
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