A new way to measure nearly nothing: Ultracold trapped atoms to measure pressure

A new way to measure nearly nothing
Schematic diagram of NIST vacuum sensor design. Credit: Daniel Barker/NIST








Animation of the NIST cold-atom vacuum standard (CAVS) device. Researchers attach the CAVS device to the vacuum chamber they want to measure. When the CAVS and vacuum chamber reach equilibrium pressure, lithium atoms are introduced into the CAVS. As the atoms move into the device chamber, they are slowed by laser light and then captured by a combination of laser light and magnetic fields. This trapping process causes the atoms to fluoresce, emitting light in all directions. Some of the emitted light is captured by a detector. When a molecule of background gas collides with a trapped atom, it can knock the atom out of the trap. Every time an atom is lost from the trap, the total fluorescence diminishes. By measuring changes to the emitted light, researchers can measure the rate at which atoms are lost from the trap, which provides a sensitive indicator of pressure in the chamber. Credit: Sean Kelley/NIST








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More information: Stephen Eckel et al, Challenges to miniaturizing cold atom technology for deployable vacuum metrology, Metrologia (2018). DOI: 10.1088/1681-7575/aadbe4
Journal information: Metrologia

Citation: A new way to measure nearly nothing: Ultracold trapped atoms to measure pressure (2018, October 20) retrieved 20 April 2019 from https://phys.org/news/2018-10-ultracold-atoms-pressure.html

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Oct 20, 2018
The Vacuum

There is a simple, almost unbelievably simple method, of bringing the vacuous vacuum down here to earth, by the occupants of the International Space Station!

The vacuous vacuum that is space
While that unobtainable vacuum
Unobtainable down on earth
But in the outer reaches
Between satellite and planets
Exists a vacuum most pure
That even the station that's in space
That in its cubic capacity
If its vacuum is packaged
In vacuum containers
When brought back down to earth
Will give a vacuum most pure
That only exists in the vacuum that is space

Oct 20, 2018
@Gr: Nice blank verse, but impracticable due multiple factors. One is ISS' low orbit, so not a really, really 'hard' vacuum, even with a wake shield. Another is limited size of vessels, and their mass. Third, out-gassing from those vessels' interior, even with electron-beam etc surface treatments...

I did just enough with 'mild' vacuum to 'tip my hat' to those working with the 'hard stuff'.

Oct 20, 2018
Divide your cubic vacuum into Half a Vacuum

Simply go to a higher orbit, a point is reached at one atom a cubic metre so by subdividing your cube you will reach a point where a pure vacuum is reached, as then you do not need to go to a higher orbit.
