There are three different standard styles of research dewars to select from; exchange gas, flowing vapor, or cold finger. Each 'Performance by Design' system has different features to meet your research needs.

The central sample tube is surrounded by the liquid nitrogen reservoir. Load your samples into this tube; adjust the amount of exchange gas and samples will immediately begin to cool.The exchange gas thermally couples the sample to liquid nitrogen.The amount of thermal coupling depends on the exchange gas pressure.

The model 5 NVT research dewar is variable temperature in the range <77 to 325K (600K optional). Temperature is controlled by the exchange gas pressure and the power dissipated in the heater that is wound on the sample mount. Temperatures below 77K can be reached by pumping on the nitrogen bath.

This model is a true 'Performance by design' system. It is manufactured of highly polished stainless steel. It is reconfigurable to meet future experimental requirements. This research dewar is easy to fill and operate. Is also has a long hold time.

Liquid nitrogen flows from the reservoir through the adjustable flow valve to the vaporizer at the bottom of the sample tube. Applying heat vaporizes the liquid and raises the gas temperature. This gas enters the sample zone to cool the sample to your selected temperature. Load your samples into this flowing nitrogen gas that exits from the vaporizer, (also known as the diffuser or heat exchanger). Samples can be changed while operating.

The temperature of the sample can be varied typically 77 to 325K by adjusting the electrical current supplied to the heater on the heat exchanger. This heater is located inside the sample tube - not in vacuum; this eliminates problems due to high latent heat of vaporization of liquid nitrogen.

Many standard cryostats are available with an adjustable thermal link built into the liquid nitrogen reservoir. This link isolates the samples from the liquid nitrogen and allows super variable temperature operation, from 77 to 325K (1000K optional). Temperatures below 77K can be reached by pumping the nitrogen reservoir. This link isolates the samples from the liquid nitrogen and allows super variable temperature operations, from 77 to 325K (1000K optional). Temperatures below 77K can be reached by pumping the nitrogen bath.

This system is a unique design with many features. It is a compact dewar that is very easy to operate, no experience necessary. There is no flow to control, and no capillary or flow line to plug. No reservoir pressure regulation is needed, and no exchange gas is required. The liquid nitrogen reservoir can be refilled without disturbing the set point for a virtually unlimited hold time. Also, multiple cold fingers, operating simultaneously at different temperatures, can be installed in one cryostat.