Imaging apparatus are used in a toroid cavity detector for nuclear magnetic resonance (NMR) analysis to hold samples relative to a principal detector element which is a flat metal conductor, the plane of which is parallel to the longitudinal axis of the toroid cavity. A sample is held adjacent to or in contact with the principal detector element so that the sample can be subjected to NMR analysis when a static main homogeneous magnetic field (B0) produced by a NMR magnetic device is applied to the toroid cavity and an RF excitation signal pulse is supplied from a potentiostat to the principal detector element so that an alternately energized and de-energized magnetic field (B1) is produced in the sample and through the toroid cavity. The sample may be components of a coin cell battery which are mounted within the toroid cavity relative to the principal detector element by an non-conductive coin cell battery imager or a press assembly so that the components are hermetically sealed together and so that a direct current potential can be applied to the components. Alternately, a sample is positioned within an O-ring maintained relative to the principal detector element by a pair of glass plates that are disposed on opposite sides of the principal detector element and are compressed toward each other so that NMR analysis can be used to analyze light transmitted through the sample or to analyze a sample separated from the principal detector element by semi-permeable membranes.