Design and Analysis of the Novel Test Tube Magnet as a Device for Portable Nuclear Magnetic Resonance

We present a novel test tube magnet (TTM) for use in portable nuclear magnetic resonance (NMR) devices. The TTM consists of a dipole cylinder magnet and a hemisphere magnet. The hemisphere magnet is attached to one end of the dipole cylinder magnet, so that the whole magnet is shaped like a test tube. TTM generates a wide-diameter spherical volume (DSV) with a high magnetic field homogeneity, which makes the device suitable for portable NMR. We simulated the configuration with three-dimensional finite-element methods. Flux density elements are effectively corrected in the homogeneous magnetic field region. The homogeneity increases, the magnet volumes and mass relatively decrease, and the construction is fairly simple. Overall, the new design has improved characteristics for portable NMR.