Measurement of wire diameter by optical diffraction

✍ Scribed by Soraya A. Khodier

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 256 KB
• Volume: 36
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(03)00134-8

✦ Synopsis

A combined interference and di raction pattern, in the form of equidistant interference fringes, resulting from illuminating a vertical metallic wire by a laser beam is analyzed to measure the diameter of four standard wires. The diameters range from 170 to 450 m. It is found that the error in the diameter measurements increases for small metallic wires and for small distances between the wire and the screen due to scattering e ects. The intensity of the incident laser beam was controlled by a pair of sheet polaroids to minimize the scattered radiation. The used technique is highly sensitive, but requires controlled environmental conditions and absence of vibration e ects. The expanded uncertainty for k = 2 is calculated and found to decrease from U (D) = ±1:45 m for the wire of nominal diameter 170 m to ±0:57 m for the diameter 450 m.