The low temperature control system, ER 4112HV, makes use of liquid helium as coolant. The accessible temperature range is 3.8 K to 300 K. The system consists of the following parts:

• Continous Flow Liquid Helium Cryostat with 10 mm o.d. Quarz Dewar and Sample Holder
• Digital Helium Control Unit
• Liquid Helium Flow Controller
• Helium Transfer Tube
• Membrane Pump
• Tubing
• Clamps for attaching the cryostat to the magnet

X-Band waveguide-type cavities are mounted to the liquid helium cryostat (see right), while the sample is inserted into the quarz dewar. Therein, it is held in a steam of temperature controlled helium gas. Sample exchange at any temperature is a standard feature of this system.

The digital helium control unit monitors and controls the temperature measured with a thermosensor close to sample's position. It features PID temperature control (proportional, integral and derivative). The control unit is fully remote controlable via the acquisition software Xepr or WinEPR Acquisition of the ELEXSYS and EMX spectrometer series.

The helium transfer tube is an ultra low loss gas shielded transfer tube. The cold helium from the storage dewar/tank is shielded by the helium gas which returns from the cryostat. The helium flow is controlled via a needle valve which is located in the lower part of the transfer tube that is immersed in the liquid helium tank. The needle is adjusted manually via the top of the tube (standard option). Automated versions are available upon request.