The system sets or ramps the temperature of the sample under test. It is modular and can be combined with any Novocontrol BDS dielectric or impedance spectrometer.
The Novocool Cryosystem was designed for easy, safe and fully automatic operation enabling computer controlled experiments over several days without supervision as required for low frequency measurements.
- Economical temperature control system
- Temperature range −100 °C ... +250 °C
- Temperature ramps from 0.1 .. 20 °C/min
- Temperature accuracy ±0.3 °C
- Fast stabilization with nearly no overshooting by tuned control parameters
- Low liquid nitrogen consumption (< 1.5 l/hr at T> −50 °C)
- Microprocessor controller with 24 bit ADC and GPIB communication port
Principle of operation
The gas flows directly to the sample cell which is inserted from the cryostat upper side.
The temperature is measured at the sample cell lower electrode. In order to optimize temperature control and establish save operation under any conditions, the temperature of the cold gas is measured with an additional gas temperature sensor. The Novocool cryostat is super isolated and therefore no vacuum is required.
The flow of liquid nitrogen is determined by the pressure inside the dewar. For optimized operation, the dewar pressure is adjusted by the Novocool microprocessor control unit. For this purpose, a second control loop is used consisting of a pressure sensor, dewar heater (to create pressure) and the pressure valve (to release pressure).