Quantum Hall Resistance (QHR) Standard

Click image to enlarge

The Quantum Hall Resistance system provides an absolute value of resistance related to the von Klitzing constant of 25812.807 Ohms. To provide this reference, a Quantum Hall semiconducting device is maintained at 0.3 K with a He-3 refrigerator in a magnetic field of up to 14 Tesla, generated by a superconducting magnet. Under these conditions the Quantum Hall plateaux of resistance are easily obtained.

Cryogenic offers a QHR reference standard with its own Cryogenic platform consisting of a QHR sample, a Variable Temperature Insert temperature, a magnet with up to 16 Tesla magnetic field, magnet power supply, temperature controller, and an oil free mechanical pump as a complete system.

Cryogenic is now able to offer the QHR system in a completely liquid helium free environment.  The system is cooled by a pulse-tube cryocooler, for low vibration and low maintenance (every three years).  The system has a special built-in facility for liquefying helium gas from room temperature (no cryogens required for start-up or operation).

The miniature cryogen free QHR system up to 9 Tesla is also available suited for graphene measurements requiring lower magnetic fields.

Share this Bookmark & Share