Bridge12 is currently developing an integrated THz system for NMR-DNP spectroscopy. The basic idea is to operate the gyrotron inside the NMR magnet, just above the NMR probe head, effectively eliminating the need of a second superconducting magnet. This article is about a ferroshim insert that we had to develop for this purpose.
Ryan, H., J. van Bentum, and T. Maly, A ferromagnetic shim insert for NMR magnets – Towards an integrated gyrotron for DNP-NMR spectroscopy. J. Magn. Reson., 2017. 277: p. 1-7.
In recent years high-field Dynamic Nuclear Polarization (DNP) enhanced NMR spectroscopy has gained significant interest. In high-field DNP-NMR experiments (⩾400 MHz 1H NMR, ⩾9.4 T) often a stand-alone gyrotron is used to generate high microwave/THz power to produce sufficiently high microwave induced B1e fields at the position of the NMR sample. These devices typically require a second, stand-alone superconducting magnet to operate. Here we present the design and realization of a ferroshim insert, to create two iso-centers inside a commercially available wide-bore NMR magnet. This work is part of a larger project to integrate a gyrotron into NMR magnets, effectively eliminating the need for a second, stand-alone superconducting magnet.