Sow Hsin Chen from the Department of Nuclear Science and Engineering of the Massachusetts Institute of Technology (MIT) received the 2015 Guinier Prize at the SAS2015 meeting in Berlin. On Thursday afternoon, September 17, he delivered a plenary talk covering just a few of his many contributions to science and to the field of small-angle scattering methods development and applications in fundamental studies of soft condensed matter. He described his most recent work using small-angle neutron scattering to measure and discover a density minimum in deeply supercooled water that further demonstrates the plausibility of the existence of the second critical point in supercooled water. He also spoke about many of his long-lasting contributions in the field of small-angle scattering, such as:

• the first use of neutron contrast variation to elucidate and propose the microstructure of SDS micelles and reversed micelles;
• formulation of the so-called decoupling approximation to handle the calculation of the small-angle neutron scattering intensity distribution of interacting non-spherical particles in solution and to correct for the effect of polydispersity;
• a fractal approach to calculating the scattering intensity distribution of protein-detergent complexes in solution;
• devising a contrast variation method to measure the average mean curvature of surfactant films in a bi-continuous micro-emulsion;
• proposing and implementing a Clipped Random Wave Model which enabled the successful measurement of the average Gaussian Curvature of the surfactant film.

The Guinier prize recognizes either lifetime achievement, or a major breakthrough, or an outstanding contribution to the field of small-angle scattering. As Sow Hsin Chen’s plenary unfolded it was clear to all present that he met all three of these criteria. As he acknowledged the contributions of his many students, post docs and collaborators throughout his talk, it was evident that he had educated and inspired a whole generation of today's research leaders in his field of study.

After his plenary talk, at the Conference banquet, accompanied by his wife Ching-chih Chen, Professor Chen was presented with his prize and some small gifts to remember Berlin and the occasion.

Jill Trewhella
Chair, IUCr Commission on Small-Angle Scattering