Abstract: 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.