A smoke detection device main body of a portable smoke detector (10) can switch smoke detection sensitivity. At the start of operation, the detection smoke sensitivity of the portable smoke detector is equal to or higher than a detection sensitivity of smoke in a fixed smoke detector (100) that detects smoke in a monitoring area. At this time, switching of smoke detection sensitivity does not work. After the fixed smoke detector detects smoke generation, when the portable smoke detector is used to locate the smoke generation position while moving in the monitoring area, an operation is performed from an initial sensitivity. When a predetermined smoke detection signal is detected while using the portable smoke detector to identify the smoke generation position, the smoke detection sensitivity switching will be activated, and then the smoke detection sensitivity will be changed accordingly. By lowering, the smoke generation position is narrowed down and identified.

A measuring apparatus includes a flow cell through which a sample containing particles flows, a light source for irradiating light on the sample flowing through the flow cell, a fluorescence detector for detecting the fluorescence generated from the sample irradiated with light from the light source, and a control unit for flowing a positive control sample containing a fluorescent dye through the flow cell, measuring the fluorescence generated from the positive control sample irradiated by the light from the light source via the fluorescence detector, comparing the obtained measurement value and a reference value, and adjusting the detection sensitivity of the fluorescence detector according to the comparison result.

The present invention belongs to the technical field of trace gas detection, and relates to a multi-cavity semi-open resonant photoacoustic cell and a multi-gas simultaneous measurement system. The photoacoustic cell includes multiple resonant cavities. Each resonant cavity has a unique length and a unique resonant frequency, so each resonant cavity corresponds to one to-be-measured gas. A sensitive diaphragm of an acoustic sensor is fixed on one end face of the photoacoustic cell. Photoacoustic signals of different frequencies generated in the resonant cavities act on the sensitive diaphragm of the acoustic sensor, causing the sensitive diaphragm of the acoustic sensor to vibrate periodically. Concentration information of multiple to-be-measured gases can be obtained by analyzing the vibration of the sensitive diaphragm of the acoustic sensor.

A system and method to discriminate between a first preselected gas and at least one other preselected gas use of an absorption spectroscopy analyzer that includes a Herriott cell and a temperature sensitive light source. The light source operates at a temperature that emits a beam at a wavelength that corresponds to high absorption by a first preselected gas. When a predetermined level of this gas is detected in a gas sample, the analyzer changes the operating temperature of the light source to emit a beam at a wavelength that corresponds to high absorption by a second preselected gas. The second preselected gas can be a different isotope of the first preselected gas.

A luminometer (400) includes a light detector (630) configured to sense photons (135). The luminometer (400) includes an analog circuit (915a) configured to provide an analog signal (965) based on the photons (135) emitted from assay reactions over a time period and a counter circuit (915b) configured to provide a photon count (970) based on the photons (135) emitted from the assay reactions over the time period. The luminometer (400) includes a luminometer controller (905) configured to, in response to an analog signal value of the analog signal (965) being greater than a predetermined value, determine and report a measurement value of the photons (135) emitted from the assay reactions over the time period based on the analog signal value of the analog signal (965) and a linear function (1010). Optionally, the linear function (1010) is derived from a relationship between the analog signal (965) and the photon count (970).

An apparatus may have a first reflector and a second reflector positioned on either side of a sample volume for a gas sample. The configuration of the first reflector may be variable between at least first and second configurations, wherein each of the first and second configurations is arranged such that a beam of optical radiation from an optical beam origin is directed to a detector location via the sample volume. In the second configuration the beam of optical radiation is reflected at least once from each of the first and second reflectors and the path length of the beam of optical radiation through the sample volume is greater than in the first configuration.

Assays (100) may be performed with a luminometer (400) having a chassis (405) that may include a reaction vessel chamber (610). The luminometer (400) may also include a light passage (640) that intersects the reaction vessel chamber (610). The luminometer (400) may also include a cap (415) that, when in a closed configuration, prevents light emitted by external sources from entering the reaction vessel chamber (610) and from entering the light passage (640). The cap (415) may provide access to the reaction vessel chamber (610) when in an open configuration. The luminometer (400) may also include a calibration light source (460) optically coupled to one end of the light passage (640) and a light detector (630) optically coupled to another end of the light passage (640). The light detector (630) may include a sensing element for receiving light from the light passage (640).

Aspects of the present disclosure describe gas sensor calibration methods and subsequent sensing methods employing same in conjunction with wavelength modulation spectroscopy (WMS). Additional aspects of the present disclosure advantageously employ WMS for highly-sensitive gas concentration measurement across a range of concentrations from ambient to a high concentration environment such as fire/smoke detection. Finally, still further aspects of the present disclosure determine and then employ two calibration factors and during measurement WMS-2f spectra to determine an inflection or turning point and subsequently which one of the two calibration factors to employ at a given concentration.

A system for measuring with the aid of light absorption spectrometry the concentration of one or more analytes in porewater in soil, the system comprising: one or more monitoring unit(s), each monitoring unit comprising a porewater sampler (1), an optical flow cell (2) with a tube connecting the liquid inlet port of said optical flow cell to said porewater sampler; and vacuum arrangement to enable extraction of porewater; at least one light source (5) for generating a light beam to be transmitted through said optical flow cell (2); and at least one detector (8) for obtaining spectral information from the beam exiting said optical flow cell. A method of measurement is also provided.

Aspects of the present disclosure describe gas sensor calibration methods and subsequent sensing methods employing same in conjunction with wavelength modulation spectroscopy (WMS). Additional aspects of the present disclosure advantageously employ WMS for highly-sensitive gas concentration measurement across a range of concentrations from ambient to a high concentration environment such as fire/smoke detection. Finally, still further aspects of the present disclosure determine and then employ two calibration factors and during measurement WMS-2f spectra to determine an inflection or turning point and subsequently which one of the two calibration factors to employ at a given concentration.