John helliwell crystallography

Durward William John Cruickshank, often known as D.
W.
J.
Cruickshank, was a British crystallographer whose work transformed the precision of determining molecular structures from X-ray crystal structure analysis.
He developed the theoretical framework for anisotropic displacement parameters, also known as the thermal ellipsoid, for crystal structure determination in a series of papers published in 1956 in Acta Crystallographica.

John R.
Helliwell is a British crystallographer known for his pioneering work in the use of synchrotron radiation in macromolecular crystallography.