Bragg centennial Acta Crystallographica Section A Foundations of Lawrence Bragg’s interest in the deformation of Crystallography metals and 1950–1953 in the Cavendish – a ISSN 0108-7673 worm’s-eye view Received 24 May 2012 Accepted 2 August 2012 Anthony Kelly Churchill College, University of Cambridge, Storeys Way, Cambridge CB3 0DS, United Kingdom. Correspondence e-mail:
[email protected] This paper recounts the atmosphere in the Cavendish Laboratory during Lawrence Bragg’s triumphant final years there through the eyes and the work of a young research student, and hence reflects some measure of Bragg’s personality. The opportunity is taken to deal in detail with Bragg’s contribution to our understanding of crystal plasticity, which is seldom described, being overshadowed by his many superb contributions to the determination of crystal structure. Bragg produced in 1940–1942, through his development of the bubble model of a crystal structure, the first demonstration of how crystal dislocations move. His suggestion of the use of microbeams led rather directly to the development of modern thin-film transmission electron microscopy. 1. Introduction Taylor was common at the time. I was assigned to this group, I believe, because when interviewed by Schonberg earlier in William Lawrence Bragg (WLB) came to Cambridge from the 1950 I had suggested that I was interested in sub-grains in National Physical Laboratory (NPL) in October 1938, metals and their analogues as Bitter patterns – in those days, succeeding Rutherford, the New Zealander, as he had done at prospective research students were expected to suggest a Manchester. He had been at the NPL only from November problem on which he or she would like to work (Kelly, 2005).