Optistat^®SXM Liquid Helium (LHe) bath cryostat for low-vibration optical spectroscopy and nano-scale microscopy

Optistat®SXM Liquid Helium (LHe) bath cryostat for low-vibration optical spectroscopy and nano-scale microscopy

The OptistatSXM is specifically designed for optical spectroscopy and nano-scale microscopy experiments that require:

• Base temperatures down to 1.6 K
• Low vibration - the OptistatSXM enables vibration-sensitive measurements such as SPM, NSOM, STM and AFM at low temperature by avoiding the use of a nitrogen reservoir and the vibration that would result
• 49 mm sample space
• Quick sample change
• Sample in dynamic exchange gas
• Generous f2.2 radial optical access, with 4 radial and 1 axial window

Operation

The OptistatSXM cryostat contains an integral liquid helium reservoir with a variable temperature insert (VTI) and radiation shields cooled by the evaporating helium. In the OptistatSXM, the sample is in a dynamic exchange gas environment, meaning that the cryogen flows into the sample space cooling the sample directly.

Liquid helium is supplied from the reservoir to the VTI through a needle valve, allowing the flow to be optimised to suit the operating requirements. A heat exchanger at the bottom of the sample space is fitted with a heater and temperature sensor, so that the temperature of the helium flowing through the sample space can be controlled by a temperature controller. This helium then flows over the sample and out of the cryostat to a small vacuum pump, which is used to promote the flow and obtain temperatures below 4.2 K.

The sample is mounted on a sample rod and loaded into the cryostat through a NW50 flange. Changing the sample simply involves removing the sample rod, replacing the sample and inserting the rod back into the cryostat.