JEOL, NMR and ESR: A 65 year evolution.

Abstract

Felix Bloch and Edward Purcell successfully detected NMR signals in 1946, and VARIAN was the first company in the world to complete a commercial product in 1950. JEOL released their first commercial NMR instrument 6 years later. At that time, the magnetic field intensity was 30-40 MHz, so the ability to separate signals was extremely low. The users of NMR wanted higher magnetic fields, and the key issue for NMR manufacturers became how to increase the magnetic field strength. With a permanent magnet, the maximum magnetic field is 90 MHz (2.11 Tesla), and the limit with an electromagnet is 100 MHz (2.4 Tesla). This limitation was removed with the advent of superconducting magnets (SCM). Furthermore, in addition to the Continuous Wave method, which only allowed observation of 1H nuclei, Pulse Fourier Transform (FT) methods were developed, enabling observation and measurement of 13C and other nuclei. The development of SCM and FT was epoch-making for NMR, and the field has flourished since then. Of course, there has been technical innovation that could not be accomplished by the NMR manufacturers alone, such as the development of superconducting materials and winding techniques for SCM, and new algorithm development and the acceleration of computing speeds for FT. This report will relate the story of NMR, including these developments that have provided the background.