Provisional Low Temperature Scale of 2000 explained

The Provisional Low Temperature Scale of 2000 (PLTS-2000) is an equipment calibration standard for making measurements of very low temperatures, in the range of 0.9 mK (millikelvin) to 1 K, adopted by the International Committee for Weights and Measures in October 2000. It is based on the melting pressure of solidified helium-3.^{[1] [2] [3]}

At these low temperatures, the melting pressure of helium-3 varies from about 2.9 MPa to nearly 4.0 MPa. At the temperature of approximately 315 mK, a minimum of pressure (2.9 MPa) occurs. Although this gives a disadvantage of non-monotonicity, in that two different temperatures can give the same pressure, the scale is otherwise robust since the melting pressure of helium-3 is insensitive to many experimental factors.

See also

• International Temperature Scale of 1990 (ITS-90) — the calibration standard used for all temperatures above 0.6 K
• Leiden scale

Notes and References

1. Book: 978-3-540-46356-6 . Matter and Methods at Low Temperatures . 3rd . Pobell . F. . Frank Pobell . 2007 . Springer .
2. Web site: The Provisional Low Temperature Scale from 0.9 mK to 1 K, PLTS-2000 . . December 11, 2013.
3. Web site: Supplementary Information for the ITS-90. International Bureau of Weights and Measures. December 11, 2013. dead. https://web.archive.org/web/20120910075232/http://www.bipm.org/en/publications/mep_kelvin/its-90_supplementary.html. 2012-09-10.