Distance determination by the gamma-ray time-of-flight method

Author

Kostamovaara, Juha ; Karras, Matti

Author_Institution

Dept. of Electr. Eng., Oulu Univ., Finland

Volume

41

Issue

5

fYear

1992

fDate

10/1/1992 12:00:00 AM

Firstpage

616

Lastpage

621

Abstract

The time-of-flight method is studied using coincident annihilation gamma rays with an energy of 511 keV to find the distance from a surface at which they are scattered back for detection. The gamma rays have a good penetration ability, which makes the method suitable for industrial circumstances in which the range is rendered opaque to light by flue gas and aerosols. An accuracy of 1 cm over a distance of 2 m can be obtained by increasing the averaging time by the square of the lengthening factor. The density of the surface can be studied by recording the width of the distribution of the surface measurements. This measurement needs a prolonged averaging time, but the thickness of the slag layer on top of a steel melt can be measured with a maximum error of 1.5 cm at short distances, for example

Keywords

distance measurement; gamma-ray applications; thickness measurement; 511 keV; aerosols; averaging time; coincident annihilation gamma rays; density; flue gas; gamma-ray time-of-flight method; industrial applications; metallurgical industry; slag layer; slag thickness; steel melt; surface measurements; thickness; Aerosols; Density measurement; Flue gases; Gamma ray detection; Gamma ray detectors; Gamma rays; Gas industry; Light scattering; Thickness measurement; Time measurement;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.177331

Filename

177331