Metal Processing at Culham

  • I. J. Spalding
Part of the NATO Advanced Study Institutes Series book series (NSSB, volume 84)


The Laser Applications Group at Culham utilizes a wide range of commercially-available and in-house CO2 laser systems, covering the power range 5–15,000 Watts (continuous). The sub-kilowatt systems utilize stable optical resonators, providing Gaussian-mode outputs, and some of these have high mean-power pulsing facilities at repetition rates up to 1 kHz. The highest power in routine use is the 5–6kW unstable-cavity (M=2 ~3) output from the transverse-flow CL5 laser, discussed in the first lecture. Detailed numerical simulations of the behaviour of this laser have been undertaken: Figure 1 illustrates the good agreement obtained between the computed small-signal gain αo (full curve) and that measured experimentally as a function of gas flow velocity and the distance z downstream of the electrode (Armandillo and Kaye, 1980). To obtain this agreement CO2 dissociation of ~50% has been assumed. Lower dissociation (and higher gain) are observed immediately after switching on; here the Culham code agrees with the numerical predictions and experimental observations reported by Yoder et al (1978). Representative near and far-field burns from this laser are shown in Figure 2. (More quantitative measurements are made using high-speed IR cameras on irradiated targets. With f/4 spherical mirror optics not less than 80% of the power is focussed through an aperture of diameter 0.3mm onto a calorimetric detector such as a ‘Joule Stick’).


Metal Processing Full Curve Detailed Numerical Simulation Calorimetric Detector Nuclear Power Development 
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  1. Armandillo, E. and Kaye, A.S., 1980, J. Phys. D:Appl. Phys. 13, 321.CrossRefGoogle Scholar
  2. Higginson, P.R. and Campbell, D.A., 1980, Paper 21 in Proceedings of B.N.E.S. Conference on Post Irradiation Examination, Crange-over-Sands, UK, May 1980.Google Scholar
  3. Hill, J.W., Lee, M.J. and Spalding, I.J., 1974, Optics and Laser Technology, 6, 276.CrossRefGoogle Scholar
  4. Trafford, D.N.R., Bell, T., Megaw, J.H.P.C. and Bransden, A.S., 1979, Proceedings of ’Heat Treatment 1979’ Conference, Birmingham 22-24 May 1979, Metals Society/Am. Soc. for Metals.Google Scholar
  5. Yoder, M.J., Legner, W.H., Jacob, J.H. and Abhouse, D.R., 1978, J. Appl. Phys. 49, 3171.CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • I. J. Spalding
    • 1
  1. 1.Culham LaboratoryUKAEAAbingdon, OxonUK

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