ThermoSpectra Corp. of Franklin, Mass., has acquired TopoMetrix Corp. of Santa Clara, Calif., for $8 million. ThermoSpectra's subsidiary, Park Scientific Instruments Inc. of Sunnyvale, Calif., will merge with the acquired company under the name ThermoMicroscopes. The new venture will manufacture high-resolution scanning probe microscopes for the materials science and industrial applications market. TopoMetrix, headquartered only four miles away from Park Scientific, manufactures and sells computerized atomic-force and near-field optical microscopes and other scanning probe microscopes for research and industrial applications. Park Scientific, founded by Stanford University researchers in 1988, specializes in ambient and ultrahigh-vacuum scanning probe microscopes for R&D applications in materials science.