DISCUSSION 



2^Klemens, p. G. Handhuch d. Physik, Vol. 14: Springer, Berlin, 1956, p. 198 

 25KLEMENS, P. G. Solid State Physics, Vol. 7: Academic Press Inc., New York, 1958, 



p. 1 

 26 Kemp, W. R. G., Klemens, P. G., Tainsh, R.J. and White, G. K. Acta Metallurgica 



5 (1957) 303 

 2'Berman, R. Proc. roy. Soc. /I 208 (1951) 90 

 28 Herman, R., Foster, E. L. and Rosenberg, H. M. Report on the Conference on 



Defects in Crystalline Solids The Physical Society, London, 1955 

 29WITTELS, M. C. and Sherrill, F. A. Phys. Rev. 93 (1954) 1117 

 30PRIMAK, W., FucHS, L. H. and Day, P. 'Phys. Rev. 91 (1953) 551 

 siPRiMAK, W., FucHS. L. K. and Day, P. /. Amer. ceram. Soc. 38 (1955) 135 

 32 Klemens, P. G. Phil. Mag. 1 (1956) 938 

 3 3PRIMAK, W. Phys. Rev. 95 (1954) 837 

 3*Stevels, J. M. Progress in the Theory of the Physical Properties of Glass: Elsevier, 



Amsterdam, 1948 

 35\Vittels, M. C. Phil. Mag. 2 (1957) 1445 

 36 Cohen, A. F. /. appl. Phys. 29 (1958) 591 



DISCUSSION 



Dr. Segal: Dr. Klemens has discussed the irradiation damage in the temperature 

 range between liquid helium and room temperatures. I wonder if he could tell us 

 whether any work has been done at very high temperatures, say, up to about 3000°C. 

 Dr. Klemens: I am not aware of any studies of irradiation effects, in which the 

 material was kept at very high temperatures during irradiation, although such studies 

 may have been carried out in connection with the development of reactors working 

 at high temperatures. In most substances annealing takes place at high temperatures 

 and it is more profitable to irradiate at low temperatures and subsequently increase 

 the temperature, studying the annealing behaviour. From such knowledge one can 

 deduce the behaviour during irradiation at high temperatures. 



Dr. Green : I wonder if Dr. Klemens would agree that the reason why very little 

 irradiation-damage work has been done on complex compounds and biological 

 chemicals is that the experimental techniques necessary to find out what has hap- 

 pened are somewhat complex ? Would he also agree that we now have a seemingly 

 useful tool, the electron paramagnetic resonance method, which is particularly 

 suitable for compounds of biological significance, so that much information may be 

 derived in this manner in the future? 



Dr. Klemens : Yes, this is certainly so. I have recently seen an illustration of the 

 power of the paramagnetic resonance method at Oak Ridge, where this technique 

 is used to study the eflfects of neutron irradiation on crystalline and vitreous silica, 

 thus providing further information on the problem which I have discussed in my 

 paper. 



281 



