A guided stage mechanism suitable for supporting a reticle in a photolithography machine includes a stage movable in the X-Y directions on a base. The invention is based on NMR relaxation measurements determining longitudinal relaxation times T1 instead of the standard T2 measurements, and involves saturating a relatively wide sensitive region of the formation and processing NMR echo signals which originate approximately from the center of the sensitive region. Methods for their preparation and use are also provided. The communications are analyzed to identify any initial VoIP data.