The approach to 1 GHz plus high resolution NMR

Traditionally, im1 reused field strength in high resolution NMR magnets h us been sought for the study of the structure of molecules of increasing slice. The number of t pec Irai lines associated with larger molecules requires tlie increased line separation and sensitivity afforded by higher fields, Recently, additional benefits of high fields have been realized due to mechanisms of line width minimization at fields which are being approached in avail«ble spectrometer magnets. As a result, the motivation for increased field strength in NMR magnets is as strong as ever. There arc currently in progress a number of programs with the objective of NMR at 1 GHz, corresponding to 23.5 T and above. The possibility of these high fields depends, as n necessary condition, on the availability of a superconductor and associated coil technology for that field. Efforts are underway for the development of I1TS conductor for this application, In addition, development continues on NbjSn conductor with improved high field properties. Wide bore NMR magnets are currently being fabricated to provide a field of 21.1 T, nr a proton resonant frequency of 900 MHz. These magnets were conceived as platforms for the demonstration of higher fields with the incorporation nf »dditiuntil inner coils. Given the spatial restrictions in the present 90ft MHz magnets, the prospects of achieving higher fields are examined through estimates of required current densities for given Held increments.