There is provided a method of tuning a resonant cavity and a cavity ring-down spectroscopy system using the same. A first mirror is actuated at a first end of a resonant cavity to move in a direction between a first position relative to a second mirror at a second end of the resonant cavity, at which a cavity length between the first mirror and the second mirror is less than a resonance length for a laser beam, and a second position relative to the second mirror, at which the cavity length is greater than the resonance length. An event is triggered when the cavity length is proximal to the resonance length. The first mirror is continuously actuated in the direction between the first position and the second position during the event.

Methods and systems for analyzing a sample and generating a predictive model using cavity ring-down spectroscopy are disclosed. At least part of a sample is loaded in a ring-down cavity. For each of a set of wavelengths, a laser beam is generated and directed into the ring-down cavity. The laser beam entering the ring-down cavity is extinguished. Light intensity decay data for light exiting the ring-down cavity is registered via a light intensity sensor system. A probability is determined from the light intensity decay data for the set of wavelengths that a subject from which the sample was received has a physiological condition or a degree of the physiological condition at least indirectly using a dataset of light intensity decay data for previously analyzed samples for which the presence or the absence of the physiological condition or the degree of the physiological condition have been identified.

A nephelometric turbidimeter for measuring a turbidity of a liquid sample in a transparent sample cuvette. The nephelometric turbidimeter includes a cuvette chamber housing with a cuvette chamber having the transparent sample cuvette arranged therein, and a drying apparatus. The drying apparatus includes a cuvette chamber inlet opening which vents the cuvette chamber, a cuvette chamber outlet opening which de-vents the cuvette chamber, an air circulator which circulates air from the cuvette chamber outlet opening to the cuvette chamber inlet opening, and a drying body. The drying body is provided as a container of a hygroscopic agent defined by a drying substance which is arranged in a drying path between the cuvette chamber outlet opening and the cuvette chamber inlet opening so that air flows through the drying body.

The present invention relates to a gas sensor (100) comprising a measurement chamber (102) for measuring presence of a first gas, the first gas being nitrous oxide (N.sub.2O) and an optical source (103) for emitting radiation in the measurement chamber (102). The sensor also comprises a radiation detector (104) sensitive to radiation emitted by the optical source (103), the radiation being detected by the radiation detector (104) following passage through the measurement chamber (102). A diffusion layer (131) is configured to allow diffusion of ambient gas into and out from the measurement chamber (102), and the diffusion layer (131) comprises means (133) for preventing diffusion of carbon dioxide (CO.sub.2) in the ambient gas into the measurement chamber (102). The invention also relates a nitrous oxide detector comprising such a gas sensor, and a method for determining presence of nitrous oxide in the ambience.

A nephelometric turbidimeter for measuring a turbidity of a liquid sample in a transparent sample cuvette. The nephelometric turbidimeter includes a cuvette chamber housing with a cuvette chamber having the transparent sample cuvette arranged therein, and a drying apparatus. The drying apparatus includes a cuvette chamber inlet opening which vents the cuvette chamber, a cuvette chamber outlet opening which de-vents the cuvette chamber, an air circulator which circulates air from the cuvette chamber outlet opening to the cuvette chamber inlet opening, and a drying body. The drying body is provided as a container of a hygroscopic agent defined by a drying substance which is arranged in a drying path between the cuvette chamber outlet opening and the cuvette chamber inlet opening so that air flows through the drying body.

The present invention relates to a gas sensor (100) comprising a measurement chamber (102) for measuring presence of a first gas, the first gas being nitrous oxide (N.sub.2O) and an optical source (103) for emitting radiation in the measurement chamber (102). The sensor also comprises a radiation detector (104) sensitive to radiation emitted by the optical source (103), the radiation being detected by the radiation detector (104) following passage through the measurement chamber (102). A diffusion layer (131) is configured to allow diffusion of ambient gas into and out from the measurement chamber (102), and the diffusion layer (131) comprises means (133) for preventing diffusion of carbon dioxide (CO.sub.2) in the ambient gas into the measurement chamber (102). The invention also relates a nitrous oxide detector comprising such a gas sensor, and a method for determining presence of nitrous oxide in the ambience.