System for sampling gas from a solid porous medium

A system for sampling gas from a solid porous medium, especially for determining a flow rate of gas diffusing from said solid porous medium, the solid porous medium being bounded by a surface,

• the system comprising:
• a sampling chamber, extending along a longitudinal axis, which
• is intended to be pressed at least partially into the solid porous medium by a longitudinal insertion end, which sampling chamber is delimited by a casing, a portion of which is gas-permeable to allow gas to diffuse from the solid porous medium into the sampling chamber, an outlet opening also being formed in the casing;
• an outlet duct, one part of which is connected to an external medium and another part of which is connected directly or indirectly to the outlet opening;
• a pipe extending from a first end connected to the sampling chamber to a second end connected to an external medium through a control member that enables or prevents passage of a gas flow through this pipe;
• a suction pump for suctioning, through the outlet opening, a gas from the sampling chamber to the outlet duct;
• wherein:
• along the longitudinal axis, the first end of the pipe is closer to the insertion end than the outlet opening is.