Search results

Describes a passive, open‐path infrared gas detector that utilises thermal background radiation as the source. Explains its mode of operation, provides a specification and considers its route to market.

Describes a unique optical source, the quantum cascade laser (QCL) and its application to gas detection. The instruments can detect both nitric oxide and carbon monoxide at concentrations down to 10 ppb m at atmospheric temperature and pressure with a 1 m absorption path‐length. A QCL operating at 5.8 μm can be used during airborne surveys of atmospheric formaldehyde, a key intermediate in the oxidation of methane and other hydrocarbons which contribute to the formation of ozone precursors.

Describes the development of low cost optical sensor systems for water quality monitoring developed under the “LOADMON” EU research programme. It uses two laser diodes as the sources: one emits blue light at 405 nm and the other red light at 670 nm. The former excites fluorescence of organic materials present in the sample and the red light creates a scatter signal from the suspended particles. The system uses a rotating mirror which allows the light spots to be swept across the sample's surface under computer control until they are below the detector.

Describes the use of a distributed optical temperature sensor, based on fibre Bragg grating technology, to monitor the temperature distribution of helium within a prototype airship.

This paper, describes the development and application of a wireless‐based stress monitoring system. Application areas include railway track and rolling stock monitoring as well as large structures, such as oil rigs and bridges.

This paper describes the use of fibre‐optics for seismic monitoring in oil wells. Based on fibre Bragg grating technology, the system can withstand temperatures of up to 175°C and extremely high pressures. It allows seismic surveys to be undertaken throughout the lifetime of the well.

Discusses recent progress in technology based on electromagnetic radiation at terahertz frequencies. Considers recent corporate activities and describes technological developments with applications in the physical and life sciences.

Reviews the Institute of Physics conference “Sensors & their Applications XI”, held at City University, UK in September 2001. Highlights a selection of key papers covering gas sensor arrays for fire detection, fibre optic sensors for structural strain monitoring and detection of biofouling, fluorescent sensor for detecting algae and thick film sensors for smartcard biometrics. Reviews briefly other papers and draws conclusions.