What's more, the prototype NIST refrigerator, which measures a few inches in outer dimensions, enables researchers to place any suitable object in the cooling zone and later remove and replace it, similar to an all-purpose kitchen refrigerator. The cooling power is the equivalent of a window-mounted air conditioner cooling a building the size of the Lincoln Memorial in Washington, D.C.
"It's one of the most flabbergasting results I've seen," project leader Joel Ullom says. "We used quantum mechanics in a nanostructure to cool a block of copper. The copper is about a million times heavier than the refrigerating elements. This is a rare example of a nano- or microelectromechanical machine that can manipulate the macroscopic world."
The technology may offer a compact, convenient means of chilling advanced sensors below standard cryogenic temperatures—300 milliKelvin (mK), typically achieved by use of liquid helium—to enhance their performance in quantum information systems, telescope cameras, and searches for mysterious dark matter and dark energy.
As described in Applied Physics Letters,* the NIST refrigerator's cooling elements, consisting of 48 tiny sandwiches of specific materials, chilled a plate of copper, 2.5 centimeters on a side and 3 millimeters thick, from 290 mK to 256 mK. The cooling process took about 18 hours. NIST researchers expect that minor improvements will enable faster and further cooling to about 100 mK.
The cooling elements are sandwiches of a normal metal, a 1-nanometer-thick insulating layer, and a superconducting metal. When a voltage is applied, the hottest electrons "tunnel" from the normal metal through the insulator to the superconductor. The temperature in the normal metal drops dramatically and drains electronic and vibrational energy from the object being cooled.
NIST researchers previously demonstrated this basic cooling method** but are now able to cool larger objects that can be easily attached and removed. Researchers developed a micromachining process to attach the cooling elements to the copper plate, which is designed to be a stage on which other objects can be attached and cooled. Additional advances include better thermal isolation of the stage, which is suspended by strong, cold-tolerant cords.
Cooling to temperatures below 300 mK currently requires complex, large and costly apparatus. NIST researchers want to build simple, compact alternatives to make it easier to cool NIST's advanced sensors. Researchers plan to boost the cooling power of the prototype refrigerator by adding more and higher-efficiency superconducting junctions and building a more rigid support structure.
This work is supported by the National Aeronautics and Space Administration.
* P.J. Lowell, G.C. O'Neil, J.M. Underwood and J.N. Ullom. Macroscale refrigeration by nanoscale electron transport. Applied Physics Letters. 102, 082601 (2013); Published online 26 Feb. 26, 2013. http://dx.doi.org/10.1063/1.4793515.
** See 2005 NIST Tech Beat article, "Chip-scale Refrigerators Cool Bulk Objects," at http://www.nist.gov/pml/div686/chip_scale_042105.cfm.
Laura Ost | Source: EurekAlert!
Further information: www.nist.gov
Further Reports about: Applied and Environmental Microbiology > Applied Physics > Applied Physics Letters > cold-tolerant cords > dark energy > liquid helium > micro- and nanostructures > nano- or microelectromechanical machine > Quantum physics > solid-state refrigerator
More articles from Power and Electrical Engineering:
Cradle turns smartphone into handheld biosensor
24.05.2013 | University of Illinois at Urbana-Champaign
Not Just Blowing in the Wind: Compressing Air for Renewable Energy Storage
22.05.2013 | Pacific Northwest National Laboratory
This morning at 05:45 CEST, the earth trembled beneath the Okhotsk Sea in the Pacific Northwest. The quake, with a magnitude of 8.2, took place at an exceptional depth of 605 kilometers.
Because of the great depth of the earthquake a tsunami is not expected and there should also be no major damage due to shaking.
Professor Frederik Tilmann of the GFZ German Research Centre for Geosciences: "The epicenter is exceptionally deep, far below the earth's crust in the mantle. Such strong ...
The Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn.
He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of ...
New indicator molecules visualise the activation of auto-aggressive T cells in the body as never before
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to examine individual cells and their activity directly in the tissue.
The development of new microscopes and fluorescent dyes in ...
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
24.05.2013 | Life Sciences
24.05.2013 | Ecology, The Environment and Conservation
24.05.2013 | Physics and Astronomy
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News