News tagged with liquid helium
Physicists capture first images of atomic spin
(PhysOrg.com) -- Though scientists argue that the emerging technology of spintronics may trump conventional electronics for building the next generation of faster, smaller, more efficient computers and high-tech ...
Apr 26, 2010 |
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Decorated with Electric Current, Nanoribbons Align with Expectations
(PhysOrg.com) -- A bizarre substance predicted to shrink electronics and give quantum physicists a new tabletop toy behaves pretty much as its designers expected.
Nanotechnology / Nanomaterials
Jan 27, 2010 |
4.9 / 5 (31) |
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LHC now colder than deep space
(PhysOrg.com) -- The LHC (Large Hadron Collider) is once again colder than deep space as it is prepared for experiments to resume in late November.
Oct 20, 2009 |
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Particle collider: Black hole or crucial machine?
(AP) -- When launched to great fanfare nearly a year ago, some feared the Large Hadron Collider would create a black hole that would suck in the world. It turns out the Hadron may be the black hole.
Aug 07, 2009 |
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Superconductivity breakthrough could lead to more cost effective technologies
Researchers from the Universities of Liverpool and Durham have fitted another piece into the superconductivity puzzle that could help in the quest to bring down the cost of technologies such as MRI scanners ...
May 24, 2010 |
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Physicists hit on mathematical description of superfluid dynamics
(PhysOrg.com) -- It has been 100 years since the discovery of superconductivity, a state achieved when mercury was cooled, with the help of liquid helium, to nearly the coldest temperature achievable to form ...
Jun 09, 2011 |
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Quantum hot potato: Researchers entice two atoms to swap smallest energy units
Physicists at the National Institute of Standards and Technology (NIST) have for the first time coaxed two atoms in separate locations to take turns jiggling back and forth while swapping the smallest measurable ...
Feb 23, 2011 |
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The perfect liquid -- now even more perfect
Ultra hot quark-gluon-plasma, generated by heavy-ion collisions in particle accelerators, is supposed to be the "most perfect fluid" in the world. Previous theories imposed a limit on how "liquid" fluids can ...
Jan 17, 2012 |
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Restart of Large Hadron Collider now November
(AP) -- Repairs to two small helium leaks in the world's largest atom smasher will delay the restart of the giant machine another month until November, a spokesman for the operator said Thursday.
Jul 30, 2009 |
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Physicist finds colder isn't always slower as electron emissions increase at temps to -452 F
(PhysOrg.com) -- Science is detective work so it was not unexpected that new questions would follow old ones as Indiana University Bloomington nuclear physicist Hans-Otto Meyer's work progressed on testing ...
Apr 28, 2010 |
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Space Station to Receive New Anti-Matter Detector Component
(PhysOrg.com) -- Scientist plan on replacing the liquid helium cooled magnet, in the anti-matter detector, with an Alpha Magnetic Spectrometer. This will increase the life span of the detector from 3 years ...
Space & Earth / Space Exploration
Apr 27, 2010 |
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Spitzer Telescope Warms Up to New Career
The primary mission of NASA's Spitzer Space Telescope is about to end after more than five and a half years of probing the cosmos with its keen infrared eye. Within about a week of May 12, the telescope is ...
Space & Earth / Space Exploration
May 06, 2009 |
5 / 5 (6) |
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Space telescope's new survey of outer galaxy helps astronomers study stars
The Spitzer Space Telescope is now taking aim at the outer reaches of the Milky Way and helping two Iowa State University astronomers advance their star studies.
Aug 30, 2010 |
5 / 5 (5) |
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Researchers putting a freeze on oscillator vibrations
University of Oregon physicists have successfully landed a one-two punch on a tiny glass sphere, refrigerating it in liquid helium and then dosing its perimeter with a laser beam, to bring its naturally occurring mechanical ...
Jun 17, 2009 |
4.4 / 5 (5) |
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If Spitzer Could Talk: An Interview with NASA's Coolest Space Telescope
NASA's Spitzer Space Telescope is about to use its last drop of the coolant that has chilled it for the past five-and-a-half years. On about May 12, give or take a week or so, the observatory is predicted ...
Space & Earth / Space Exploration
May 05, 2009 |
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Liquid helium
Helium exists in liquid form only at extremely low temperatures. The boiling point and critical point depend on the isotope of the helium; see the table below for values. The density of liquid helium at its boiling point and 1 atm is approximately 0.125 g/mL
Helium-4 was first liquefied on 10 July 1908 by Dutch physicist Heike Kamerlingh Onnes. Liquid helium-4 is used as a cryogenic refrigerant; it is produced commercially for use in superconducting magnets such as those used in MRI or NMR. It is liquefied using the Hampson-Linde cycle.[citation needed]
The temperatures required to liquefy helium are low because of the weakness of the attraction between helium atoms. The interatomic forces are weak in the first place because helium is a noble gas, but the interatomic attraction is reduced even further by quantum effects, which are important in helium because of its low atomic mass. The zero point energy of the liquid is less if the atoms are less confined by their neighbors; thus the liquid can lower its ground state energy by increasing the interatomic distance. But at this greater distance, the effect of interatomic forces is even weaker.[citation needed]
Because of the weak interatomic forces, helium remains liquid down to absolute zero; helium solidifies only under great pressure. At sufficiently low temperature, both helium-3 and helium-4 undergo a transition to a superfluid phase (see table below).[citation needed]
Liquid helium-3 and helium-4 are not completely miscible below 0.9 K at the saturated vapor pressure. Below this temperature a mixture of the two isotopes undergoes phase separation into a lighter normal fluid that is mostly helium-3, and a denser superfluid that is mostly helium-4. (This occurs because the system can lower its enthalpy by separating.) At low temperatures, the helium-4 rich phase may contain up to 6% of helium-3 in solution, which makes possible the existence of the dilution refrigerator, capable of reaching temperatures of a few mK above absolute zero.[citation needed]
For more information about Liquid helium, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
