National Physical Laboratory

Gauge block interferometer and training delivered in Qatar

The Qatar Armed Forces Calibration Centre (QAFCC) in Doha has taken delivery of a gauge block interferometer designed by the National Physical Laboratory (NPL) and manufactured under licence by Hexagon Metrology UK.

Director of Qatar Armed Forces Calibration Center Brigadier Adel Hassan A R Fakhroo takes delivery of the NPL-designed instrument from Hexagon

Director of Qatar Armed Forces Calibration Center Brigadier Adel Hassan A R Fakhroo
takes delivery of the NPL-designed instrument from Hexagon
(photo courtesy of Hexagon Metrology)

Gauge blocks are one of the most popular length standards in use throughout the world, providing traceability to the SI metre. The NPL-designed gauge block interferometers, sold commercially through Hexagon Metrology, are used worldwide for the highest accuracy calibration of gauge blocks and similar engineering artefact standards.

Qatar became an Associate State of the General Conference on Weights and Measures on 10 March 2016 and is a Signatory of the CIPM Mutual Recognition Arrangement.

Staff from NPL, local agent Prompt Engineering and QAFCC in Doha (photo courtesy of Hexagon Metrology)

Staff from NPL, local agent Prompt Engineering and QAFCC in Doha
(photo courtesy of Hexagon Metrology)

Following installation of the interferometer by Hexagon Metrology, Andrew Lewis from NPL's Dimensional Measurement group travelled to QAFCC to deliver training in the calibration of gauge blocks by interferometry.

The NPL gauge block interferometer was designed and licensed to Hexagon Metrology nearly 30 years ago and several iterations and variations of the basic design have been produced. The latest version of the instrument uses a phase-stepping technique to measure the surface topography of the gauge block, as well as a dual laser system to determine the absolute length. Uncertainties of around 20 to 30 nanometres can be achieved on gauge blocks up to 100 millimetres in length.

The C++ instrument control software, developed at NPL by Ben Hughes and Andrew Lewis, is also sold through Hexagon Metrology, and stabilised lasers used in the interferometers are manufactured by Hexagon under NPL licence. Instruments and lasers based on NPL designs have been sold to 28 different countries worldwide, with typical customers including National Measurement Institutes, accredited laboratories and high technology laboratories and organisations.

Find out more about NPL's gauge block interferometer

Find out more about NPL's work on Dimensional Measurement

Find out more about primary calibration equipment from Hexagon Metrology

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Last Updated: 18 Apr 2017
Created: 12 Apr 2017

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