Abstract: A mass spectrometer with a wide dynamic range, having:—a source (2) of ion beams,—an analyzer (4) for the ion beams generated by said source (2),—a detector (6) for the ions separated by said analyzer (4),—a treatment stage (8) for the analogue signal A generated by said detector, to obtain two separate signals A1=mA and A2=nA, where m>n, characterised by comprising:—an analogue/digital converter (10) for converting both said analogue signals A1 and A2 into two numerical values D1 and D2,—a controller (12) which receives both the numerical values D1 and D2 as input, and provides as output a single value equal to D1 if D1 is less than the end-of-scale value of the converter (10), or a value equal to (m/n)D2 if D1 is equal to the end-of-scale value of the converter.