Abstract: A current sensing noise thermometer comprising: a sensor resistor thermally coupled to a target to be measured; a superconducting coil; superconducting thermal breaks between respective ends of the sensor resistor and respective ends of the superconducting coil; and a superconducting flux sensor; wherein the sensor resistor, superconducting coil and superconducting thermal breaks form a loop inductively coupled to the superconducting flux sensor. There may be a noise filter between the sensor resistor and the superconducting coil.