Standard Small Angle Generator Using Laser Interferometer

Abstract

Small angle generator is equipment used for making an adjustable small inclined angle. This equipment is use for calibration of gradual scale of level measurement instrument, such as, bubble level, electronic level, inclinometer, survey scope, collimator, etc. In the research, the possible method to make the low cost high accuracy small angle generator is studied. The materials employed in this project are available in Thailand. The accuracy of the inclined angle measurement relies on the sine principle of triangle. Hypotenuse length (l) of 500-650 mm is measured by steel ruler which uncertainty about ±0.5 mm. The small displacement of the opposite side (Δh) is determined by the Michelson’s interferometer. The shift of one fringe is half wavelength of 650 nm laser diode. The constructed system is capable to measure inclined angle of resolution about 325 nm /500 mm or about an order of 1 nm/m.