Thesis-1986-Godfrey.pdf (4.53 MB)
Optical detection system for ultrasonic surface displacements
thesis
posted on 2018-01-09, 11:19 authored by Martin W. GodfreyThe work was carried out with the aim of developing an optical
interferometric detection system. This was to be applied to the
quantative measurement of low amplitude, high frequency surface
displacements (<1nm at several MHz). Two forms of interferometric
detector are investigated. The performance and limitations in
particular measurement situations are assessed for both types of
interferometer. The first type of detector investigated is a miniature
stabilised interferometer. The design of a stabilisation system is
given, along with ways in which it can be optimised for a particular
environment. The second type of detector studied is a quadrature
interferometer. Various methods of processing the two channels of
information from this device are discussed. The design of a new method
of processing the signals is given, and its performance determined.
The interferometric sensor is combined with a waveform digitiser
and microcomputer to form an integrated detection system. Analysis of
the waveforms obtained is performed by a system of Pascal programs
developed for this purpose. The detection system is applied to tasks
such as the calibration of other forms of transducer and the
characterisation of artificial sources of acoustic emission. The
results of experimental studies are given and the applications of such a
system discussed.
Funding
SERC and Rolls Royce Ltd. (CASE studentship).
History
School
- Science
Department
- Physics
Publisher
© M.W. GodfreyPublisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 2.5 Generic (CC BY-NC-ND 2.5) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by-nc-nd/2.5/Publication date
1986Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.Language
- en