liquid helium


Liquid helium

liquid helium

[′lik·wəd ′hē·lē·əm] (cryogenics) The state of helium which exists at atmospheric pressure at temperatures below -268.95°C (4.2 K), and for temperatures near absolute zero at pressures up to about 25 atmospheres (2.53 megapascals); has two phases, helium I and helium II.