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Traceable Temperatures - Contents

Preface to first edition

Preface to second edition

General reading for first edition

Acknowledgements for first edition

Acknowledgements for figures and tables

1 MEASUREMENT AND TRACEABILITY

1.1 Introduction
1.2 Measurement

     1.2.1 What is a measurement?
     1.2.2 Measurement scales
     1.2.3 The problem of definition and the importance of purpose
     1.2.4 Decision, risk and uncertainty
1.3 Temperature
    1.3.1 The evolution of the temperature scale
    1.3.2 Thermodynamic temperature
    1.3.3 Meteorological temperatures
1.4 Traceability
    1.4.1 Defining traceability
    1.4.2 Achieving traceability
1.5 The SI
     1.5.1 The Metre Convention
     1.5.2 The SI units and conventions
1.6 Documentary Standards
1.7 Laboratory Accreditation to ISO/IEC 17025
1.8 National Measurement System
Further Reading

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2 UNCERTAINTY IN MEASUREMENT

2.1 Introduction
2.2 Risk, Uncertainty and Error
2.3 Distributions, Mean and Variance
     2.3.1 Discrete distributions
     2.3.2 Continuous distributions
2.4 The Normal Distribution
2.5 Experimental Measurements of Mean and Variance
2.6 Evaluating Type A Uncertainties
     2.6.1 Evaluating uncertainties of single-valued quantities
     2.6.2 The Student's t-distribution
     2.6.3 Evaluating uncertainties for distributed quantities
2.7 Evaluating Type B Uncertainties
     2.7.1 Identification and recording influences
     2.7.2 Theoretical evaluations
     2.7.3 Evaluations based on single subsidiary measurements
     2.7.4 Evaluations based on data provided from other sources
     2.7.5 Evaluations based on intuition and experience
2.8 Combining Uncertainties
2.9 Propagation of Uncertainty
2.10 Correlated Uncertainties
2.11 Interpolation
     2.11.1 Lagrange interpolation
     2.11.2 Propagation of Uncertainty
     2.11.3 Interpolation error
     2.11.4 Other interpolations
2.12 Least-squares Fitting
     2.12.1 Propagation of Uncertainty
2.13 The ISO Guide and its Application
     2.13.1 Application to non-normal distribution
     2.13.2 Application to distributed quantities
     2.13.3 The nature of confidence intervals
     2.13.4 Alternative methods
2.14 Reporting Uncertainties
     2.14.1 How many decimal places?
     2.14.2 Presentation of uncertainty statements
Further reading

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3 THE ITS-90 TEMPERATURE SCALE

3.1 Introduction
3.2 The Triple Point of Water
     3.2.1 The units of temperature
     3.2.2 The triple point of water - defining the unit
     3.2.3 Using the triple-point cell
     3.2.4 The ice point
3.3 ITS-90
    3.3.1 The principles of ITS-90
    3.3.2 The metal fixed pointsl
    3.3.3 The cryogenic triple points
    3.3.4 The cryogenic vapour-pressure points
    3.3.5 Platinum resistance thermometry
    3.3.6 Radiation thermometry
    3.3.7 Cryogenic thermometry
3.4 The Propagation of Uncertainty on ITS-90
Further reading

4 USE OF THERMOMETERS

4.1 Introduction
4.2 Heat Transfer
     4.2.1 Conduction
     4.2.2 Convection
4.3 Thermal Properties of Materials
    4.3.1 Thermal conductivity
    4.3.2 Heat capacity
    4.3.3 Latent heat
4.4 Errors in the Use of Thermometers
    4.4.l Immersion errors
    4.4.2 Heat capacity errors
    4.4.3 Settling response errors
    4.4.4 Lag errors with steadily changing temperatures
    4.4.5 Radiation errors and shielding
4.5 Models and methods
     4.5.1 Electrical analogue models
     4.5.2 Composite systems
     4.5.3 Temperature in non-equilibrium situations
     4.5.4 Immersion revisited
     4.5.5 Time constants revisited
     4.5.6 Guarding
     4.5.7 Temperature control
Further reading

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5 CALIBRATION

5.l Introduction
5.2 The Meaning of Calibration
    5.2.1 What is a calibration?
    5.2.2 What is not a calibration?
5.3 Calibration Design
    5.3.1 The thermometer under test
    5.3.2 The client's needs
    5.3.3 Establishing the link to the SI
    5.3.4 Assessing the uncertainty
    5.3.5 Reliability and generic history
    5.3.6 Recalibration and specific history
5.4 Documentary Requirements
    5.4.1 Staff training
    5.4.2 Calibration procedures
    5.4.3 Uncertainty analysis and best measurement capability
    5.4.4 Calibration records
    5.4.5 Calibration certificates
5.5 Calibration Methods
    5.5.1 Collating the information
    5.5.2 A calibration procedure
    5.5.3 Rising-temperature comparisons
    5.5.4 Example: Calibration of a short-range working thermometer
    5.5.5 Fixed-temperature comparisons
    5.5.6 Example: Calibration of a reference thermometer
Further reading

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6 PLATINUM RESISTANCE THERMOMETRY

6.1 Introduction
6.2 Resistance in Metals
     6.2.1 Introduction
     6.2.2 The effects of temperature on resistance
     6.2.3 The effects of impurities on resistance
6.3 Platinum Resistance Thermometers
    6.3.1 Electrical properties of platinum thermometers
    6.3.2 Construction of platinum thermometers
    6.3.3 Standard platinum resistance thermometers
    6.3.4 Partially supported platinum thermometers
    6.3.5 Fully supported platinum thermometers
    6.3.6 Platinum film thermometers
    6.3.7 Sheathing
    6.3.8 Lead wires
    6.3.9 Electrical insulation
6.4 Resistance Measurements
    6.4.1 General principles
    6.4.2 Two-, three- and four-lead measurements
    6.4.3 D.C. resistance measurement
    6.4.4 A.C. resistance measurement
    6.4.5 Verification and calibration of resistance bridges
6.5 Errors in Resistance Thermometry
    6.5.1 Immersion errors
    6.5.2 Lag and settling errors
    6.5.3 Radiation errors
    6.5.4 Self-heating
    6.5.5 Mechanical shock and vibration
    6.5.6 Thermal expansion effects
    6.5.7 Other thermal effects
    6.5.8 Contamination
    6.5.9 Compensation and assessment of drift
    6.5.10 Leakage effects
    6.5.11 A.C. leakage effects
    6.5.12 Electromagnetic interference
    6.5.13 Lead-resistance errors
    6.5.14 Thermoelectric effects
    6.5.15 Reference resistor stability and accuracy
6.6 Choice and Use of Resistance Thermometers
    6.6.1 Choosing and using a thermometer
    6.6.2 Care and maintenance

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6.7 Calibration of Resistance Thermometers
    6.7.1 Calibration equations
    6.7.2 Calibration at fixed points
    6.7.3 Calibration by least squares
    6.7.4 A calibration procedure
6.8 Other Resistance Thermometers
    6.8.1 Thermistors
    6.8.2 Copper and nickel resistance thermometers
    6.8.3 Rhodium - iron thermometer
    6.8.4 Germanium resistance thermometer
 Further reading

7 LIQUID-IN-GLASS THERMOMETRY

7.1 Introduction
7.2 Construction of Liquid-in-glass Thermometers
    7.2.1 Solid-stem thermometers
    7.2.2 Enclosed-scale thermometers
7.3 Errors in Liquid-in-glass Thermometry
    7.3.1 Time constant effects
    7.3.2 Heat capacity effects
    7.3.3 Pressure effects
    7.3.4 Bulb hysteresis and drift
    7.3.5 Bore non-uniformity effects
    7.3.6 Stiction
    7.3.7 Separated columns
    7.3.8 Errors in reading
    7.3.9 Immersion errors
    7.3.10 Scale errors
7.4 Choice and Use of Liquid-in-glass Thermometers
    7.4.1 Range and Type
    7.4.2 Acceptance
    7.4.3 Etching and engraving
    7.4.4 Use of the thermometer
    7.4.5 Organic liquids
    7.4.6 Storage
    7.4.7 Transport
7.5 Calibration
    7.5.1 Short-range calibration
    7.5.2 Calibration of reference and general-purpose thermometers
    7.5.3 Outline of a liquid-in-glass calibration procedure
    Further reading

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8 THERMOCOUPLE THERMOMETRY

8.1 Introduction
8.2 The Thermoelectric Effects
    8.2.1 The Peltier effect
    8.2.2 The Thomson effect
    8.2.3 The Seebeck effect
    8.2.4 Exploiting the Seebeck effect to measure temperature
    8.2.5 A model of a thermocouple measurement
8.3 Thermocouple types
    8.3.1 Standard thermocouple types
    8.3.2 Rare-metal thermocouples
    8.3.3 Base-metal thermocouples
    8.3.4 Non-standard thermocouples
8.4 Construction
    8.4.1 Junctions
    8.4.2 Joins
    8.4.3 Extension leads and compensating leads
    8.4.4 Sheaths and thermowells
    8.4.5 Mineral-insulated metal sheaths
8.5 Instrumentation
    8.5.1 Reference junctions
    8.5.2 Instrument types
    8.5.3 Thermocouple calibrators
    8.5.4 Alternative thermocouple circuits
8.6 Errors in Thermocouples
    8.6.1 Thermal effects
    8.6.2 Inhomogeneity errors
    8.6.3 Isothermal errors
    8.6.4 Reference junction errors
    8.6.5 Interference errors
    8.6.6 Wire resistance errors
    8.6.7 Linearisation errors
8.7 Choice and Use of Thermocouples
    8.7.1 Selection of thermocouple types
    8.7.2 Acceptance
    8.7.3 Assembly
    8.7.4 Inhomogeneity tests
8.8 Calibration
    8.8.1 Conformance or type approval
    8.8.2 In situ calibration
    8.8.3 Rare-metal thermocouple calibration
Further reading

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9. RADIATION THERMOMETRY

9.1 Introduction
9.2 Blackbodies and Blackbody Radiation
9.3 Spectral Band Thermometers
9.4 Errors in Spectral Band Thermometry
    9.4.1 Errors in emissivity
    9.4.2 Reflection errors
    9.4.3 Absorption errors
    9.4.4 Transmission errors
    9.4.5 Non-thermal emission
    9.4.6 Scattering errors
    9.4.7 Size-of-source effects
    9.4.8 Ambient temperature dependence
    9.4.9 Vignetting
    9.4.10 Linearisation
    9.4.11 Instrumental emissivity
9.5 Use and Care of Radiation Thermometers
    9.5.1 Choosing a radiation thermometer
    9.5.2 Care and maintenance
    9.5.3 Using the thermometer
9.6 Practical Blackbodies
    9.6.1 Blackbody principles
    9.6.2 Ice-point blackbody
    9.6.3 Errors in blackbodies
9.7 Calibration of Radiation Thermometers
    9.7.1 Calibration methods
    9.7.2 Calibration equations
    9.7.3 Tungsten strip lamps
    9.7.4 Calibrating a radiation thermometer
9.8 Other Radiation Thermometers
    9.8.1 The disappearing-filament thermometer
    9.8.2 The ratio thermometer
    9.8.3 Multi-spectral radiation thermometer
    9.8.4 Total radiation thermometers
    9.8.5 Special-purpose thermometers for plastic and glass
    9.8.6 Fibre-optic thermometers
Further Reading

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APPENDIX A FURTHER INFORMATION FOR LEAST-SQUARES FITTING

APPENDIX B THE DIFFERENCE BETWEEN ITS-90 AND IPTS-68

APPENDIX C RESISTANCE THERMOMETER REFERENCE TABLES

APPENDIX D THERMOCOUPLE REFERENCE TABLES

INDEX