| CPC G01N 29/32 (2013.01) [G01N 29/222 (2013.01); G01N 29/2425 (2013.01); G01N 29/42 (2013.01); G01N 2291/021 (2013.01); G01N 2291/02809 (2013.01)] | 20 Claims |

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1. A photoacoustic gas sensor device, for determining a value indicative of a presence or a concentration of a component in a gas, the photoacoustic gas sensor device comprising:
a measurement cell enclosing a measurement volume;
a gas permeable area in the measurement cell for a gas to enter the measurement volume;
an electromagnetic radiation source arranged to emit electromagnetic radiation into the measurement volume; and
a pressure transducer arranged to measure a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component in the measurement volume,
wherein the gas permeable area is represented by a porous gas permeable membrane,
wherein an average pore size of the porous gas permeable membrane is between 10 nm and 1 μm, or between 20 nm and 200 nm,
wherein a porosity of the porous gas permeable membrane is between 20% and 90%,
wherein a dimension of the measurement volume is between 0.03 cm3 and 8 cm3, and
wherein a diameter of the gas permeable area is between 0.2 mm and 4 mm.
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