An LTS/HTS NMR magnet operated in the range 600-700 MHz

As part of our 3-phase program to develop a high resolution 1 GHz LTS/HTS NMR magnet, a system composed of a 600 MHz LTS background NMR magnet and an HTS Insert operating in the range 75 to 100 MHz has been built and tested. Operated at 4.2 K, immersed in a bath of liquid helium, the Phase 2 LTS/HTS magnet, the LTS magnet in persistent mode and the HTS insert powered by a stable supply, generated an NMR frequency of 692.2 MHz (16.26 T): the LTS magnet, with 234.4 A, at 588.7 MHz (13.83 T); and the HTS insert, with 115.95 A, at 103.5 MHz (2.43 T). This paper presents results of the magnet operation during test geared to the design of room temperature shim coils and ferromagnetic tiles. Magnetization effects of the HTS insert on field distribution are also reported.