An improved vibration-free mounting system for sample cooling and low temperature and precision spectroscopy in which a closed-cycle helium refrigerator mechanism is to be mounted adjacent to a cold test chamber to enable efficient sample cooling. The system includes a first rigid support structure which receives and supports the refrigerator mechanism, and a second rigid support structure independently receiving and supporting a shroud having a cold test chamber for housing test samples on a sample holder. The second support structure is physically isolated from the first structure to prevent the transfer of vibrations therebetween, and the first and second structures are rigidly aligned with one another along a vertical axis. A gas envelope vibration isolating connection is provided between the refrigerator mechanism and the shroud for providing thermal communication for efficient sample cooling. The second support structure is preferably mounted on a vibration isolation table having a plate-like top supported by a volume of relatively loosely packed and dry granular material such as sand. The shroud also preferably includes a flange for enabling rigid mounting of the spectrometer device adjacent the test chamber. The shroud can also comprise a removable lower section to facilitate access to the sample holder and various experimental setups.