In an ultrahigh sensitive NMR apparatus, a stability of a temperature of a very low temperature probe coil is improved. Each container and cap is mountable or provided on the common or the associated support structure, wherein each cap is formed essentially rectangular, having two shorter edges and two longer edges, and comprises: a cap body, a lid hinged to the cap body so to pivot around a pivot axis at least between closed and opened positions, the pivot axis being essentially parallel to the shorter edges. In one configuration, the clothing article can be moved upward and substantially cover an upper portion of the doll body. Fiber-optic coupling mitigates systematic errors such as variable detector group delay and provides for multiplexing multiple transmit and receive optics onto a single electro-optical system.