Research Article Open Access

Length Measurement of Long Gauge Blocks by Interferometer

Kanokporn Kohmun1, Pichet Limsuwan1, Monludee Ranusawud2 and Prathan Buranasiri1
  • 1 Department of Physics, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
  • 2 National Institute of Metrology (Thailand), Klong Luang, Pathumthani 12120, Thailand


A gauge block interferometer with a vacuum chamber was designed and constructed for the measurement of gauge block lengths between 10 to 1,000 mm. In the chamber, four gauge blocks under the length measurement can be mounted on the measuring table. Furthermore, the length of all four gauge blocks can be measured continuously in one measurement. In this study, four gauge blocks with the nominal length of 125, 200, 400 and 500 mm were used for the length measurement. The environment parameters in the vacuum chamber including temperature, pressure, relative humidity and CO2 concentration were measured. The refractive index of air which depends on environment parameters was determined by using updated Edlén equation. Then, the lengths of four gauge blocks were measured and found to be 125.00025, 200.00019, 400.00070 and 500.00064, respectively.

American Journal of Applied Sciences
Volume 17 No. 1, 2020, 196-203


Submitted On: 3 July 2020 Published On: 26 September 2020

How to Cite: Kohmun, K., Limsuwan, P., Ranusawud, M. & Buranasiri, P. (2020). Length Measurement of Long Gauge Blocks by Interferometer. American Journal of Applied Sciences, 17(1), 196-203.

  • 0 Citations



  • Long Gauge Block
  • Interferometer
  • Refractive Index of Air
  • Edlén Equation
  • Length Measurement