Optistat^®CF-V liquid helium (LHe) continuous flow optical spectroscopy cryostat
Sample in vacuum

The OptistatCF-V is a liquid helium cooled, top loading continuous flow (CF) cryostat enabling optical spectroscopy experiments that require:

• Base temperature down to 2.3 K
• Large 30 mm diameter sample space
• Minimum number of windows in the optical path, reducing reflective losses
• Generous f0.9 radial optical access with 4 radial windows and 1 axial window, with a wide range of window materials available
• Upper temperature of 500 K; having no cold windows enables the use of any window material above 300 K
• Operation in any orientation

The tails of the OptistatCF-V,  MicrostatHe and MicrostatHe Rectangular Tail  are interchangeable, enabling a modular set of optical cryostats for different experimental set-ups.

Operation

The OptistatCF-V works on a continuous flow principle using an oil-free pump to draw liquid helium from a storage dewar, along a transfer tube, to the heat exchanger ("pull" mode). If the noise and vibration from the pump are undesirable then helium liquid can be pushed through the heat exchanger by pressurising the storage vessel ("push" mode). The sample is positioned on the sample holder in good thermal contact with the heat exchanger and surrounded by a vacuum.

Temperature control is achieved by a combination of manual helium flow control and power dissipated in an electrical heater, regulated using an ITC601 temperature controller.

The OptistatCF-V will also operate with liquid nitrogen (LN2) as coolant for measurements to 80 K.

To change the sample, the cryostat is warmed to room temperature, the vacuum released and the outer case and radiation shield removed.