Features and Benefits

The Quantized Hall Resistance (QHR) Standard is internationally recognized as the representation of the ohm and is the most stable resistance standard. Many national laboratories and industries need to provide highly accurate, traceable reference standards to support their hi-tech environments. Measurements International (MI) developed the new 6800C QHR Standard System to meet the needs of national laboratories and primary industrial laboratories worldwide.

The MI 6800C QHR System is a fully automated primary standard developed as an economic means to provide a highly reproducible resistance standard.

Liquid helium shortages, erratic deliveries, and steady price increases have become commonplace. This shortage, along with continuous price increases causes many labs to have difficulty efficiently reaching their measurement goals. The 6800C requires no liquid helium to operate.

The 6800C was developed over many years’ experience in quantized hall system design, resistance measurements, and cryogenics. It is modular in design and consists of three parts: sample, cryogenics system, and bridge measurement system. These components may be purchased separately.

Several options are available including extra QHR samples, 6800C software.

Sample

The QHE device is mounted on a special probe that passes through an airlock so as to maintain the system clean and free of atmospheric gas and other impurities that may otherwise condense. This is especially important when using unprotected QHE devices as they need to be protected from water contamination. Two probes are offered, one as described for metrology purposes and the second for general use as a research tool.

The system has been specially designed for a dual sample platform to allow for GaAs/AlGaAs and Graphene QHR sample use. Both samples can be inserted at the same time for sample to sample comparison.

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The standard sample platform has 8 electrical connections using PTFE insulated silver wiring to a TO-8 socket. The probe is shipped with two TO-8 sample platforms as standard. A copper cover protects the sample during insertion and removal.

The 6800C Resistance Standard sample provides the absolute value of resistance related to the Von Klitzing constant of 25 812.807 4593 Ω. Operating on step I = 2 plateau and i = 4 plateau, the 6800C compares the QHR value of 12906.40373 Ω to either a 10 kΩ or 1 kΩ resistor. The reference or sample, developed at the National Research Council of Canada (NRCC) for Gallium Samples, and developed at the National Standards Institute of Technology (NIST) for Graphene based samples.

The 6800C system also supports other manufacturers samples.