Abstract: Gas sensor capable for in-situ non-contact optical measurements of hydrogen gas (H2) and method for measuring hydrogen gas under ambient and elevated pressures without the need for cells with extremely long optical path length. The gas sensor can be configured for dual gas measurements such as H2 and CO2.

Abstract: Gas monitor based on tuneable diode laser spectroscopy comprising at least one light source (1000) matched to at least one target gas (5000) and at least one light sensitive detector (3000), and a mirror arrangement (2000) made of a central mirror (2100) directing a light beam (4100) from the light source (1000) through the target gas (5000) to be analysed as well as a surrounding mirror (2300) around the central mirror (2100) directing the light transmitted through the gas (5000) onto at least one detector (3000). The gas monitor also comprising a control system controlling light sources (1000, 1100, 1200), digitising analogue signals as well as determining characteristics of the gas (5000). The gas monitor further comprising internal alignment means for fine alignment. The gas monitor can comprise two or more light sources (1000, 1100, 1200) targeting gases with absorption lines in two or more wavelength ranges.

Abstract: Gas monitor based on tunable diode laser spectroscopy comprising at least one light source (1000) matched to at least one target gas (5000) and at least one light sensitive detector (3000), and optical means (2000; 2200) to form light beams and direct light beams through the target gas to be analysed as well as directing the light onto at least one detector (3000). The optical means comprise a retro reflector (2200) and a mirror arrangement comprising a central mirror (2100) and a surrounding mirror (2300) arranged with an offset angle between their optical axes, the central mirror (2100) being arranged for receiving light from the light source (1000) and directing light to the retro reflector (2200), the retro reflector (2200) arranged for returning the light to the surrounding mirror (2300), and the surrounding mirror (2300) arranged for reflecting the light into the detector (3000).