Sensor Systems for Environmental Monitoring

1 Fibre optic sensors.- 1.1 Introduction to fibre optics.- 1.1.1 The need for environmental monitoring and new technology.- 1.1.2 Advantages and disadvantages of fibre optic sensors.- 1.2 Physical principles of fibre optic chemical sensors.- 1.2.1 Absorption sensors.- 1.2.2 Sensing through indicator dyes.- 1.2.3 Fluorescence sensors.- 1.2.4 Raman sensors.- 1.2.5 Refractive index and optical path length sensors.- 1.2.6 Evanescent field sensors.- 1.3 Sensor construction and basic types.- 1.3.1 Fibre optics with absorption cells.- 1.3.2 Fibre opt(r)odes.- 1.3.3 Evanescent field sensor types.- 1.3.4 Solgel coatings.- 1.3.5 Other types of sensor construction.- 1.3.6 Source and detector considerations.- 1.4 Examples of fibre optic sensors for environmental applications.- 1.4.1 Air pollutants.- 1.4.2 Seawater monitoring.- 1.4.3 Ground and drinking water contamination.- 1.4.4 Soil contamination.- 1.5 Conclusion.- 1.5.1 Summary.- 1.5.2 Future trends.- References.- 2 Integrated optic sensors.- 2.1 Introduction to integrated optics.- 2.1.1 Waveguides.- 2.1.2 Waveguide couplers.- 2.1.3 Optical modulators and switches.- 2.1.4 Integrated optic light sources.- 2.1.5 Integrated optical detectors.- 2.2 Fabrication of integrated optic devices.- 2.2.1 Materials for integrated optic devices.- 2.2.2 Fabrication and modification of thin films.- 2.2.3 Patterning processes.- 2.3 Sensor techniques in integrated optics.- 2.3.1 Evanescent waves.- 2.3.2 Spectroscopy.- 2.3.3 Ellipsometry.- 2.3.4 Surface plasmon resonance.- 2.3.5 Light scattering.- 2.3.6 Optical biosensors.- 2.4 Applications of integrated optic devices for environmental sensing.- 2.4.1 An integrated optic biosensor.- 2.4.2 An integrated optic gas sensor.- 2.5 Conclusions.- References.- 3 Laser-based sensors.- 3.1 Introduction.- 3.2 Laser mass spectrometry.- 3.2.1 Resonance ionisation mass spectrometry.- 3.2.2 Factors determining the experimental arrangement.- 3.2.3 Ultra-trace detection of explosive molecules using REMPI.- 3.2.4 Trace detection of urban impurities.- 3.2.5 Trace detection of radiotoxic isotopes by RIMS.- 3.3 Laser remote sensing.- 3.3.1 LIDAR.- 3.3.2 DIAL.- 3.4 Applications of LIDAR.- 3.4.1 Mie scattering LIDAR.- 3.4.2 Raman LIDAR.- 3.4.3 Fluorescence LIDAR.- 3.5 DIAL.- 3.6 Laser absorption spectroscopy.- 3.6.1 Transmission methods.- 3.6.2 Direct laser absorption methods.- 3.6.3 Fixed frequency laser IR spectroscopy.- 3.6.4 Photoacoustic spectroscopy.- 3.6.5 Thermal lens spectroscopy (TLS).- References.- 4 Electrochemical sensors.- 4.1 Introduction.- 4.2 Voltammetric and potentiometrie techniques.- 4.2.1 Background.- 4.2.2 Applications.- 4.3 Microelectrode voltammetric sensors.- 4.3.1 The microelectrode sensor.- 4.3.2 Principle of operation.- 4.3.3 Fabrication techniques.- 4.3.4 Microelectrode measurement system considerations.- 4.3.5 Linear ramp cyclic voltammetric measurement systems.- 4.3.6 Anodic stripping analysis.- 4.3.7 Diagnostic techniques.- 4.4 Thick film sensors.- 4.4.1 Chemical environmental sensor arrays.- 4.4.2 Palintest disposable sensors.- 4.5 Ion-selective electrodes.- 4.5.1 Ion-sensitive field effect transistors.- 4.6 Summary.- References.- 5 Gas sensors and analysers.- 5.1 Gas sensors.- 5.1.1 Portable gas detectors.- 5.1.2 Portable continuous gas monitors.- 5.1.3 Fixed continuous gas measurement installations.- 5.2 Principles of gas detection.- 5.3 Catalytic oxidation gas sensors.- 5.3.1 Unembedded resistance filament sensors.- 5.3.2 Catalytic oxidation pellistors.- 5.4 Thermal conductivity pellistors.- 5.4.1 An inexpensive gas alarm for CO2 leakages.- 5.4.2 MSA model LV combustible gas indicator.- 5.5 Taguchi sintered semiconductor sensors.- 5.5.1 Principle of operation.- 5.5.2 Diffusion-reaction model.- 5.5.3 Thermal cycling of TGS heating filaments.- 5.6 Recent developments.- 5.6.1 Electronic noses.- 5.6.2 Metal oxide sensors.- 5.6.3 Single crystal thin film sensors.- 5.6.4 Thin film metal oxide sensors.- 5.6.5 Incorporation of catalysts.- 5.7