A Measurement First: NIST 'Noise Thermometry' System Measures Boltzmann Constant (IMAGE)

National Institute of Standards and Technology (NIST)

A Measurement First: NIST 'Noise Thermometry' System Measures Boltzmann Constant

Caption

NIST physicist Samuel Benz holds the two components that are compared in the first electronic measurement of the Boltzmann constant. The ac reference signal generated by the superconducting chip (left) is compared to the "Johnson noise" of a resistor inside the glass container (right). In the experiment, the water in the container is held at its triple point temperature near 0° C or 32° F.

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Burrus/NIST

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