• Temperature controller for combi cryostats

The tSTAT310x is the temperature controller for the liquid helium and liquid nitrogen cryostats. The tSTAT310x is used with cryostats of the optCRYO and microCRYO series, as well as with variable temperature cryostat-inserts for superconducting magnets of the CryoMagn series. Technical parameters of the tSTAT310x are quoted in the tables for optical cryostat.

The tSTAT310x regulates the sample temperature in the range from 4.2 K up to 273 K. The electronic unit controls the power of the resistive heater on the sample holder as well as the needle valve opening in the gas-flow regulator (manostat), included in the cryostats set of the optCRYO and microCRYO series. The controller unit also has an integrated level gauge for liquid helium.

For temperature measurements a Cu:Cu(Fe) thermocouple is used. The Cu:Cu(Fe) thermocouple provides large thermoelectric coefficient (up to 16 µV/K) at low temperatures. To have good precision at low temperature measurements the reference sensos of the thermocouple is placed inside the liquid He reservoir. The second sensor of the thermocouple is placed near the sample at the sample holder.

The controller unit tSTAT310x has a remote control capability via a serial RS-232 interface. One can control the unit and obtain the actual status and settings by simple plain text commands. This gives an opportunity to use the cryostat in a computer-controlled measurements.

T-Couple connector

The connector for the thermocouple and level gauge is located on the front side of the controller for easy access during standard operation.

How the temperature controller works

The set value of the temperature can be given either in µV or in Kelvin. It can be set manually with the keys on the control panel or remote via the serial RS-232 interface.

How the level gauge works

The liquid helium sensor is a superconducting wire inside the sensor rod. That part of the wire, which is surrounded by liquid helium, is in the superconducting state whereas the remaining part is in the normal state. Hence, the total resistance of the wire is a measure for the level of the liquid helium.