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Isotech Temperature Calibration Articles and Journals Of Thermometry

The Isotech Article Library and Journal of Thermometry is a collection of technical articles dedicated specifically to thermometry. It includes articles related to temperature scales, different methods to realize them and practicle techniques used to calibrate interpolation devices such as SPRTs, IPRTs, Thermocouples, Thermistors and Pyrometers.

These Articles represent more than 30 years of published papers by Isotech and our colleagues within the Temperature Metrology industry. Most of these papers and temperature calibration studies arose out of our own needs for improvement in our laboratories and manufacture of temperature calibration standards.

Today Isotech operates a UKAS accredited primary laboratory with the lowest uncertainties of ANY private company in the world. Much of what we have accomplished in the field of temperature calibration is contained within these journals, we hope you will find them both informative and technically useful.

ITS-90 Fixed Points
The Establishment of ITS-90 Water Triple Point References to ±2uK, and the Assessment of 100 Water Triple Point Cells Made Between 2001 and 2006

This article presents data from a group of water triple point cells made from a still designed to produce pure, air free water of isotopic composition close to V-SMOW.
Primary Laboratory Comparisons

NTPL's experience in making the best measurements in ITS-90 Cells.
The Water Triple Point - A Reference Cell Close to the ITS-90 Value

A brief history of the Water Triple Point Cell is given leading up to the ITS-90 definition, and an explanation of the main sources of error in a cell.
The Water Triple Point Cell - An Optimal Realization

Revisting the Stimpson Ball Cell for an Optimal Water Triple Point.
Water Triple Point Analysis Comparing Cells Made From Quartz Against Those From Borosilicate Glass

A comprehensive study of Water Triple Point Cells.
A Technical Guide and Standard Practise for the Qualification and Use of Water Triple Point Cells

Different methods to realize the triple point of water for the calibration of thermometers.
Water, Ice and the Triple Point - a review of the WTP

Fascinating review of the water triple point - from the Titanic to the isotopic content of water.
Water Cell Analysis - 2001 to 2010.

Looking at 100 Cells, includes sample Isotopic Analysis Certificates.
Practical Limitations of ITS-90 From Mercury Triple Point to the Silver Freeze Point

The paper investigates the properties of thirty four lots of 6N pure metal used to make cells conforming to ITS-90 from mercury through silver over a period of twenty years.
Metal Clad Fixed Point Cells for the ITS-90

This paper presents the results from over 160 fixed point cells in quartz or metal clad which show that after proper preparation metal clad cells have similar performance to quartz clad cells.
Slim Cells: An International Comparison

Analysis and Comparisons of Isotech's Slim ITS-90 Fixed Points.
The Gallium Point, An Alternative Reference Temperature to the Water Triple Point

Considering the ITS-90 Gallium Point.
An Optimal Gallium Cell - Interoperability Between a Cell Made In England and Intercompared at NIST, to it's Reference Cell

An Open Gallium Cell of a design dating from 1973 and purity 99.999999% and made in England has been intercompared with NIST’s Reference Gallium Cell.
A Technical Guide and Standard Practice for Realizing the Melting Point of Gallium

Different methods to realize the melting point of gallium for the calibration of thermometers.
Assembling a Silver ITS-90 Fixed Point Cell Ready For The Furnace

Pictorial guide showing the assembly and testing of a cell as it is placed into a furnace.
Stem Conduction And Light Piping in ITS-90 Fixed Point Cell Assemblies at a UKAS Laboratory

Experiences in Calibrating SPRTs at NTPL.
ISOTowers: Improvements Relating to the Calibration of Thermometers

In Isothermal Towers the fixed point cell and heat pipe (or heat siphon) have been combined to produce the ideal realisations for calibrating standard thermometers.
Introducing ISOTowers

Integrated bench top apparatus for calibrating SPRTs and IPRTs with uncertainties to 0.0007°C.
Platinum Resistance Thermometers Stable to ±0.001°C Per Year

The paper analyses the stabilities both of Rtpw, Wga and WHg of SPRT’s calibrated over a number of years and concludes that Wga and WHg are much safer guides to the quality and performance of SPRTs.
Experiences with Isotech SPRT's During 2007

This paper is a unique evolution in SPRT thermometry.The included control chart for a continuously used 670SQ thermometer show the performance if used carefully without shock or vibration. Download .
Standard Platinum Resistance Thermometers - Frequently Asked Questions

Our Simple Standard Platinum Resistance Thermometers FAQ
Innovations in Thermal Metrology - Improvements at the Copper Point

The development of a HT SPRT to the Copper Point and testing with a Metal Clad Copper Cell.
Further Investigations Into The Performance of Copper Point Standard Resistance Thermometers

Isotech's novel design Copper Point Thermometer.
A New Thermometer for the Copper Point

Presenting a new design SPRT for use to 1084ºC.
The Interesting Life and Times of 108462 - a HTSPRT

Experimental results with a copper point SPRT.
High Temperature SPRTS.

History and Current Developments.
MicroK and RBC
Better Accuracy in Temperature Calibration and Measurement through a New Type of Analog-to-Digital Converter

Describes a reversal-switched DC precision thermometer that achieves performance levels previously attained only with AC resistance bridge.
Using a Substitution Measurement Topology to Eliminate the Effect of Common Mode Errors in Resistance Measurements used in Temperature Metrology.

Advantages of using a substitution measurement topology in place of the conventional common current series connection.
Cost Effective Techniques used to Validate the Performance of the microK Resistance Thermometry Instrument with sub mK Uncertainty

This article describes techniques used to validate the performance of the microK thermometry instrument, which was designed for use in high accuracy temperature measurement applications.
A Simple Resistance Network for Calibrating Resistance Bridges

Describes a simple, passive, low-cost resistance network, closely related to Hamon build-up resistors, that enables the calibration of dc and low-frequency ac resistance bridges. White, D.R.
Abstracts of Three Further Pages Relating to RBC

Further articles relating to the RBC that that enables the calibration of dc and low-frequency ac resistance bridges.
Performance Assessments Of Thermometer Resistance Bridges

NIST's assessment of Bridges using an RBC.
Industrial Calibration
How Hot is Your Block

Considering depths of immersion and probe sensors in Dry Blocks.
Industrial Measurements with Very Short Immersion

The challenge of measuring with short immersion; including surface temperatures.
Temperature Calibration; Depths of Immersion

Of all the sources of errors and uncertainties in thermal calibration by far the largest source of error and least understood effect is that of immersion of unit under test, and the reference standard.
Industrial Resistance Thermometry up to 700°C without drift or contamination

The construction and materials for high temperature IPRTs.
Changes to the International Standard for Industrial PRTs

The 2008 Edition of IEC751 attempts to clarify the differences between Platinum Wire Wound Resistors and Plat-Film substrates it also separates assemblies from the sensing element.
Automating Temperature Calibration Baths with Simple Low Cost Image Aquisition

A low cost video camera, “Web Cam” is used in conjunction with a PC and Temperature Calibration Bath to automatically calibrate handheld digital thermometers.
Gold/Platinum Thermocouple and the DC Measurement Requirements

Calibration of thermocouples - if possible at all - is a topic fraught with measurement problems.
A Quick Guide to Temperature Sensors and Calibration

Introductory Guide: From Dry Blocks to Primary Standards.
Why Laboratories need Water and Gallium Cells

Introductory Guide: If you use PRTs and SPRTs you will need Water and Gallium Fixed Point Cells.
Calibrating Thermometers

Introductory Guide: Classic article with an overview of temperature calibration.
Why Calibrate?

First published by trade magazine Mepca, appears monthly in print, and online 24/7 at
Immersion Depth Chart - Dry Block Bath

A simple chart providing guides in selecting a bath for immersion depth. Helpful when considering stem conduction / immersion error. For more in depth articles see the "Industrial Calibration" section.
Reference Tables & Journals
Industrial Platinum Resistance Thermometer Tables

EN 60751 -200 to 850°C
ITS-90 Reference Chart - Coefficent Naming

Reference Chart for ITS-90 Coefficients, shows European and US conventions for referring to coefficients across the SPRT sub ranges.
Thermometer and Thermocouple Reference Chart

Summary Data for Resistance Thermometers and Thermocouples.
ITS-90 Temperature Scale Chart.

Shows the ITS-90 Fixed Points and Sub Ranges for SPRTs
Immersion Depth Chart - Dry Block Bath

A simple chart providing guides in selecting a bath for immersion depth. Helpful when considering stem conduction / immersion error. For more in depth articles see the "Industrial Calibration" section.
LabVIEW and Isotech Controllers

Information on using National Instrument's LABVIEW with Isotech products
Serial Communication Trouble Shooting Guide: Isocal-6, Dry Blocks and Baths

Check list for communicating with an Isotech Dry Block over a serial interface (RS232).
Journal of Thermometry Index

Index of the Isotech Journal of Thermometry Volumes 1 – 10, 1990 to 2000
The Absolute, or Thermodynamic Kelvin, Temperature Scale

Fundamentals of Thermometry, Part 1: Classic Article from the Isotech Journal of Thermometry: Published 1990.
Fixed Points of the ITS-90 and Confidence in the Metal Freezing Points of ITS-90

Fundamentals of Thermometry, Part 2: Classic Article from the Isotech Journal of Thermometry: Published 1990
The Standard Platinum Resistance Thermometer

Fundamentals of Thermometry, Part 3: Classic Article from the Isotech Journal of Thermometry: Published 1990
Measuring the Resistance of Standard Platinum Resistance Thermometers

Fundamentals of Thermometry, Part 4: Classic Article from the Isotech Journal of Thermometry: Published 1991
Industrial (Use) Platinum Resistance Thermometers and Common Errors in Industrial Temperature Measurement

Fundamentals of Thermometry, Part 5: Classic Article from the Isotech Journal of Thermometry: Published 1992.
Thermistor Thermometers

Fundamentals of Thermometry, Part 6: Classic Article from the Isotech Journal of Thermometry: Published 1992
Metal Melting and Freezing Equilibria Phase, Phase Diagrams, Cryoscopic Constant

Fundamentals of Thermometry, Part 7: Classic Article from the Isotech Journal of Thermometry: Published 1993
Radiation Thermometry and Calibration

Fundamentals of Thermometry, Part 8: Classic Article from the Isotech Journal of Thermometry: Published 1993.

Fundamentals of Thermometry en español.