Obituary of Paul Callaghan (1947-2012)

the development of NMR and high-resolution NMR imaging (NMR microscopy) for the study of molecular dynamics in soft matter and porous materials

Paul T. Callaghan passed away on March 24, 2012, at his home in Wellington, New Zealand. He was born August 19, 1947 in Wanganui, New Zealand. Paul completed his undergraduate physics degree at Victoria University of Wellington and his doctoral research at Oxford University (UK). His DPhil dissertation was in low-temperature physics. In 1974, Paul became a lecturer at Massey University in Palmerston North, New Zealand. In 2001, Paul became the Alan MacDiarmid Professor of Physical Sciences at his alma mater in Wellington. During his lifetime, Paul published about 240 scientific articles and educated 24 PhD students. Paul received many major prizes as a scientist, including the AMPERE Prize (2004), the Rutherford Medal (2005), and the Günther Laukien Prize for Magnetic Resonance (2010). He was knighted in 2009 and named the New Zealander of the Year in 2011.

Paul was a major contributor to the development of NMR and high-resolution NMR imaging (NMR microscopy) for the study of molecular dynamics in soft matter and porous materials. He pioneered the concept of q-space diffraction and imaging to elucidate the molecular motions in confined spaces, developed NMR to study rheology and polymer dynamics, and advanced compact NMR instruments. In addition to his scientific contributions, Paul was a fantastic communicator who brought science to the general public. Paul campaigned for a prosperous New Zealand via the development of high-tech and high-value industries. To practice what he believed, Paul and some of his former students established Magritek, a company to commercialize novel NMR instruments.

When Paul jointed Massey University in 1974, its Chemistry Department had just acquired a NMR spectrometer, JEOL FX60, which had a 1.4Tesla electromagnet. Paul’s first major effort was to build a pulsed field gradient system for the FX60. Assisted by his first graduate student Craig Trotter, Paul used pulse-gradient spin-echo NMR to measure diffusion in anisotropic and heterogeneous environments. Paul’s second major effort on the FX60 was to build a NMR microscope, which was done largely by his remarkable graduate student Craig Eccles during the early 80s.

Paul became Professor of Physics at Massey University in 1984. When I arrived in March of 1986, Craig had just obtained his first image. My job was to improve the home-built device and to image flow velocity and self-diffusion. I made various improvements and additions on that system. The instrument would sound truly ancient today - our computer had no hard drive and ran DOS 1.1. I managed to put the raw data from a flow imaging experiment on one 5.25-inch floppy disk. One of our first experiments was to image the vascular flow in live wheat grains. That work was published in Nature in 1988, which helped establish a new field of research in which sub-100 micron structure was revealed in soft materials and biological tissue. Together, we completed many exciting projects on that ancient system during my MS and PhD research. It was also the time when Paul wrote his first book, Principles of Nuclear Magnetic Resonance Microscopy, published in 1991. Paul was a truly inspirational teacher, the best advisor you could ever have – full of ideas, passionate about the projects, extremely hardworking, and very helpful.

Ten years ago, I spent five sabbatical months in Wellington. Not only could I work with Paul once again on a research project, I was also able to introduce Paul and NZ to my then-little children (10 and 6 years old at the time). Paul often walked from his apartment to our rented house, sometimes unannounced, to join us for whatever dinner we were having. More than once, he broke our house rules to play with his food, just to illustrate a concept in physics or science to my children. One afternoon when I needed to continue an experiment, Paul volunteered to pick up my children from school. When I saw my children later in the evening, they sat quietly doing their homework while Paul was nearby working on his laptop, a remarkable scene. My children each had a round tummy, a satisfied face, and a drink cup that was engraved with the famous golden arch.

We last met in the summer of 2011 at a conference in Beijing – Paul seemed to be in excellent health after several major surgeries. However, his situation worsened rapidly and he passed away seven months later. For those who were very fortunate to know him personally, Paul was a rare individual who made a profound difference to each of us. We miss him deeply.

Yang Xia

Oakland University, Rochester, Michigan

2012 June 15