Erwin Louis Hahn (06/09/1921 – 09/20/2016) was an American physicist and the discoverer of the spin echo, one of the most fundamental methods of signal generation in magnetic resonance imaging. His work laid the foundation for MRI research and revolutionised both science and medical diagnostics. Born in 1921, he was also one of the first scientists to establish the relevance of gradient echoes and the discoverer of pulse sequences. Despite the immense importance of his research, most people have never heard the name Erwin L. Hahn: Many times he was not credited for his huge influence on science. In a 2016 interview, he said: "Spectroscopists spent a lot of time publicising what they did, and I did not. This didn't put me in the limelight. It put them in the limelight. That's what happened." 1
1 Feinberg, David A. (2016): The transformative genius of Erwin Hahn, In: Magnetic Resonance in Medicine, S. 9.
After earning a bachelor's degree in chemistry, Hahn taught radar and sonar engineering in the US Navy during World War II. He was also an assistant to betatron developer Donald William Kerst at the University of Illinois, where he earned a master's degree in 1946. In 1949, he earned a PhD in nuclear magnetic resonance. His thesis was entitled Nutation of the nuclear magnetic moment and associated effects in spin ensembles.
In the same year, Erwin Hahn discovered the spin echo by chance. He was busy shortening radio frequency pulse sequences when he saw something unusual on his pulse generator. Hahn initially thought it was a fault in the system - an "irritating glitch". But when it occurred again, he realised he was on to something new. At that time, Erwin Hahn could not have imagined how important his discovery would be.
During his scientific career, Hahn made many numerous contributions to magnetic resonance imaging and received several important awards during his lifetime, such as honorary doctorates from the Universities of Stuttgart and Oxford, memberships of the American and Russian Academies of Science and the British Royal Society. However, Erwin L. Hahn never received the Nobel Prize.
Besides his interest in physics, he had a great passion for music and especially for the physics of music. Hahn played the violin in a chamber music ensemble and taught the physics of music to students. He was considered headstrong and egocentric but also entertaining, charming and sociable. Until his death in 2016, Erwin Hahn always harboured the urge to learn something new; and still published many important publications well into old age.
On the occasion of the Institute's tenth anniversary, Prof. Lawrence Wald of Harvard University gave a memorial address to Prof. Erwin L. Hahn at the Erwin L. Hahn Lecture & Workshop. The physicist and namesake of the Institute had passed away just a few weeks earlier at the age of 95. Prof. Lawrence Wald was the last PhD student supervised by Prof. Hahn during his long career.
More information on Erwin L. Hahn's life can be found in a memoir article of Alexander Pines and Dmitry Budker.