6820T Compact Dry QHR System

  • Cryogen-free System
  • Best accuracy to 0.003 × 10-6 with CCC Model 6200A
  • Best accuracy to 0.015 × 10-6 with DCC Model 6020Q
  • NEW low-vibration design < 10 nm
  • 5 Tesla standard system magnet
  • New secure stand
  • Operational temperature < 4 K
  • 3 sample mounts (LC44 or TO8)
  • Easy-to-use, turnkey functionality
  • For use with CCC and DCC bridges
  • 6- to 7-hour cooldown rate
  • Direct transfer to 100 Ω, 1 kΩ, 10 kΩ, and 100 kΩ standards
  • 6020Q system range: 0.1 Ω to 1 MΩ with 6200A or 100 kΩ
  • Optional multiple value arrays of RK/2, 100 Ω, 1 kΩ, 10 kΩ and 100 kΩ
  • Simultaneously compare Hall bar and arrays when using 6200
  • Current Range when using 6200A
    • Three high-current ranges +/- (50 mA, 100 mA and 150 mA)
    • Five low-current ranges +/- (100 μA, 333 μA, 1 mA, 3.3 mA, and 10 mA)
Overview

The 6820T Low-Vibration QHR Tabletop System is a compact, cryogen-free solution designed for laboratories requiring direct access to a quantum-based primary resistance standard. Building on Measurements International’s expertise in quantum Hall resistance (QHR) systems and precision resistance metrology, the 6830T combines advanced cryogenic technology, automated operation, and an ultra-low-vibration design to provide a stable platform for highly accurate and repeatable QHR measurements.

Engineered with vibration levels of less than 10 nm, the 6830T minimizes mechanical disturbance at the QHR device while eliminating the need for liquid helium. This reduces operating costs, simplifies laboratory infrastructure, and removes dependence on helium availability. Its tabletop design and automated system control make primary resistance realization more accessible, reliable, and practical for national metrology institutes, calibration laboratories, and other high-level resistance measurement applications.

Magnet Specifications
Superconducting Magnet  
Magnet Type Solenoid
Rated Central Field 5.0 T
Rated Operating Current @ 6.0 T 25.45 A
Total Inductance 10.526 H
Homogeneity ± 0.2 % 1 cm DSV
Superconductor Twisted multi-filamentary Nb Ti/Cu
Fabrication Wet wound with epoxy to prevent training
Quench Protection Adiabatic protection using copper matrix and diodes

 

Cryocooler Specifications
Cryocooler  
Cooling Powers at 50 Hz 1st Stage: 35 W @ 45 K

2nd Stage: 0.9 W @ 4.2 K
Base Temperature < 3.6 K
Orientation Vertical
Maintenance Interval (in hours) 30,000 to 40,000
Ambient Temperature 5 °C to 35 °C
Bridge Specifications

6200A

Range

(1:1 Ratio)

 Accuracy

× 10-6

 Range

(1:10 Ratio)

 Accuracy

× 10-6

 Range

(1:100 Ratio)

 Accuracy

× 10-6
0.1 Ω to 0.1 Ω 0.01 0.1 Ω to 1 Ω 0.01 1 Ω to 100 Ω 0.003
1 Ω to 1 Ω 0.003 1 Ω to 10 Ω 0.003 100 Ω to 10 kΩ 0.003
10 Ω to 10 Ω 0.003 10 Ω to 100 Ω 0.003 1 kΩ to 100 kΩ 0.005
100 Ω to 100 Ω 0.003 100 Ω to 1 kΩ 0.003 10 kΩ to 1 MΩ 0.01
1 kΩ to 1 kΩ 0.003 1 kΩ to 10 kΩ 0.003
10 kΩ to 10 kΩ 0.003 1 kΩ to 13 kΩ 0.003
100 kΩ to 100 kΩ 0.005 10 kΩ to 100 kΩ 0.005
1 MΩ to 1 MΩ 0.01 100 kΩ to 1 MΩ 0.01
  • Note: Either RS or RX can be selected as the standard.

6020Q

0.1 Ω to 10 kΩ
Rx Ratio & Accuracy × 10-6
*
– 1:1 10:1 14:1
0.1 Ω < 0.02 – –
1 Ω < 0.015 < 0.015 < 0.015
10 Ω < 0.015 < 0.015 < 0.015
100 Ω < 0.015 < 0.015 < 0.015
1 kΩ < 0.015 < 0.015 < 0.015
10 kΩ < 0.02 < 0.015 –
100 kΩ – – –
  • Note: Either RS or RX can be selected as the standard. 6020Q uncertainties in the bridge and software are specified at the 2σ level (95 %) this includes all secondary specifications such as linearity and noise with a ± 2 °C temperature variance.

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