ANALYSIS AND OPINION REMEMBERING PROFESSOR BRYAN TOZER
“My father’s research group was building a q-switched ruby laser, and for this purpose he had to fly to Europe to pick up a ruby crystal and bring it back to Ottawa in his hand luggage”
The Laser Corrosion
Monitor developed by Professor Tozer and
colleagues at Marchwood Engineering Laboratories
therefore designed and built the Laser Corrosion Monitor. Put simply, this system fired a free running (pulsed) ruby laser with 0.25J, 250μs pulses into the inside reactor wall. Once the oxide layer had been ablated, which was determined by measuring the reflectivity of a HeNe laser from the metal surface, its thickness could be determined by counting the number of pulses that had been fired1. On a recent visit to the International Fusion Facility (ITER) near Marseille, I noticed the planned existence of an ‘Erosion Monitor’ laser system, to which I exclaimed: ‘That’s what my father used to do!’ Optical techniques for remote inspection and measurement were particularly suited to the nuclear electricity industry and, for this purpose MEL also developed a holographic camera system. The biennial re-licensing procedure for nuclear reactors required an extensive visual inspection of critical parts of the reactor core, boiler and cooling circuits. Holograms were a method of storing high-resolution images with a very high depth of field, which offered much higher data storage than ordinary photographs or video. The system used a 1J pulsed ruby laser to produce the reference and subject beams. The laser itself was kept remote from the reactor for operational and size considerations, while the holocamera head was placed inside the reactor, where it was typically subject to radiation fields of around 200rads per hour. Holograms produced in this way could later be used to make detailed photographs of the various parts of the reactor captured on the hologram. I can g
www.electrooptics.com | @electrooptics November 2017 Electro Optics 11
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