• due to the large temperature range Rh-Fe sensors are used. The calibration at low temperatures is bad (about +- 0.3 K).
• for temperatures > 300 K the consumption of LHe (liquid helium) increases drastically
• it is possible to work without LHe, under the condition, that the main vacuum is pumped constantly. The use of LN2 (liquid nitrogen) is mandatory.
• the consuption of liquids may be reduced by removing the exchange gas. But this will affect the temperature of the sample, the difference to the sensor temperature might get untolerably high.

No Cadmium or Indium beyond Room Temperature!