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Updated: Mar 25, 2026
08:53
Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
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Noise thermometry at ultra-low temperatures.
D Rothfuss1, A Reiser1, A Fleischmann1
1Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.
Summary
This study introduces a novel cross-correlation noise thermometry technique for ultra-low temperatures. It achieves high precision below 1 minute, offering a promising alternative to traditional methods.
Area of Science:
- Physics
- Low-temperature physics
- Metrology
Background:
- Primary thermometry options at ultra-low temperatures are limited, with (195)Pt NMR thermometers commonly used.
- Current sensing DC-SQUIDs enable noise thermometry and show potential for primary thermometry.
- Noise thermometry offers minimal heat dissipation due to the absence of a driving current.
Purpose of the Study:
- To develop and characterize a noise thermometer suitable for ultra-low temperature primary thermometry.
- To overcome limitations of amplifier noise in ultra-low temperature noise thermometry.
- To provide a precise and efficient thermometry solution for microkelvin to millikelvin ranges.
Main Methods:
- Developed a cross-correlation technique using two DC-SQUID magnetometers to measure magnetic flux fluctuations.
- Utilized the Brownian motion of electrons in a copper cylinder as the noise source.
- Characterized a copper cylinder thermometer between 42 μK and 0.8 K.
Main Results:
- The cross-correlation technique effectively reduces amplifier noise contribution.
- A precision of better than 1% is achieved in under 1 minute of measuring time.
- The thermometer exhibits extremely low power dissipation, enabling continuous operation without heating.
Conclusions:
- The developed noise thermometer is a viable primary thermometry option for ultra-low temperatures.
- The cross-correlation technique enhances the precision and efficiency of noise thermometry.
- This method offers a significant advancement for low-temperature measurements and experiments.
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