A method (10, 30,50,60,65) for measuring a content of hydrogen absorbed by permeation in a workpiece (8,86,87,91,93,69) in the form of hydrogen atoms, in order to characterize an interaction between said workpiece and said content of absorbed hydrogen that can weaken said workpiece or cause an embrittlement of said workpiece, comprising: - providing a probe (7, 38,51,61,66) comprising: - a collection element configured for being associated with said workpiece (8, 86,87,91,93,69), wherein said collection element of said probe comprises an access opening for receiving an amount of absorbed hydrogen emanating from said workpiece; - an inlet port; - a mixing chamber (7',38',51',62) arranged to pneumatically communicate with said inlet port, and with said collection element configured for mixing a measurement gas with said amount of hydrogen emanating from said workpiece, such that a gaseous mixture is formed in which said amount of emanating hydrogen is changed from said atomic form into a molecular form; characterised by - providing a solid-state sensor in an inner portion of said probe (7,38,51,61,66), in such a way that said probe (7,38,51,61,66) and said solid state sensor form a compact device; - arranging said probe (38,51,61,66) with said access opening facing said workpiece (86,87,91,93,69), such that an amount of hydrogen emanating from said workpiece (86,87,91,93,69) passes through said access opening and enters into said mixing chamber (38',51',61',66'), - creating a flow (Φ) of air as measurement gas from said inlet port through said mixing chamber (7',38',62) towards said solid-state sensor, at a predetermined flowrate, wherein said flow forms in said mixing chamber (7',38',51',62) a gaseous mixture of said air with an amount of atomic hydrogen, emanating from said workpiece into a molecular form, and causes said gaseous mixture to contact said solid-state sensor to enter said mixing chamber (7',38',51',62) through said inlet port, - measuring a hydrogen concentration in said gaseous mixture by said solid-state sensor which is pneumatically connected with said mixing chamber (7',38',62) so as to come into contact with said gaseous mixture in said mixing chamber, and generating by said solid-state sensor a measurement signal responsive to said hydrogen concentration of said gaseous mixture; - processing by a processor means connected to said solid-state sensor said measurement signal, said processor means comprising a program means which processes said measurement signal and calculates at least one parameter related to said interaction between said workpiece (8,86,87,91,93,69) and said absorbed hydrogen. - providing a probe (7, 38,51,61,66) comprising: - a collection element configured for being associated with said workpiece (8, 86,87,91,93,69), wherein said collection element of said probe comprises an access opening for receiving an amount of absorbed hydrogen emanating from said workpiece; - an inlet port; - a mixing chamber (7',38',51',62) arranged to pneumatically communicate with said inlet port, and with said collection element configured for mixing a measurement gas with said amount of hydrogen emanating from said workpiece, such that a gaseous mixture is formed in which said amount of emanating hydrogen is changed from said atomic form into a molecular form; - providing a solid-state sensor in an inner portion of said probe (7,38,51,61,66), in such a way that said probe (7,38,51,61,66) and said solid state sensor form a compact device; - arranging said probe (38,51,61,66) with said access opening facing said workpiece (86,87,91,93,69), such that an amount of hydrogen emanating from said workpiece (86,87,91,93,69) passes through said access opening and enters into said mixing chamber (38',51',61',66'), - creating a flow (Φ) of air as measurement gas from said inlet port through said mixing chamber (7',38',62) towards said solid-state sensor, at a predetermined flowrate, wherein said flow forms in said mixing chamber (7',38',51',62) a gaseous mixture of said air with an amount of atomic hydrogen, emanating from said workpiece into a molecular form, and causes said gaseous mixture to contact said solid-state sensor to enter said mixing chamber (7',38',51',62) through said inlet port, - measuring a hydrogen concentration in said gaseous mixture by said solid-state sensor which is pneumatically connected with said mixing chamber (7',38',62) so as to come into contact with said gaseous mixture in said mixing chamber, and generating by said solid-state sensor a measurement signal responsive to said hydrogen concentration of said gaseous mixture; - processing by a processor means connected to said solid-state sensor said measurement signal, said processor means comprising a program means which processes said measurement signal and calculates at least one parameter related to said interaction between said workpiece (8,86,87,91,93,69) and said absorbed hydrogen.