New Nanodevice Creates a Near Perfect Electron Stream 98
SchrodingerZ writes "Scientists from the National Physics Laboratory of the United Kingdom have teamed up with the University of Cambridge to create a new electron pump that creates a single electron stream. "The device drives electrical current by manipulating individual electrons, one-by-one at very high speed." The pump takes single electrons, and pushes it over a barrier with an indent for the electron to fall into, and is then sent to the opposite side of the barrier with astounding precision. "By employing this technique, the team were able to pump almost a billion electrons per second, 300 times faster than the previous record for an accurate electron pump set at the National Institute of Standards and Technology (NIST) in the USA in 1996." Although the current was very small (150 picoamperes), this event could cause a shift from the ampere measure of current to a smaller, more precise unit of measurement for electrical current."
Re:Practical applications/implications of this? (Score:2, Informative)
Really obvious one, very accurate lab current standard (hook a electron pump up to a clock derived from a rubidium gas cell standard).
1A = 6.241x10^18 electrons/second (Score:5, Informative)
A billion electrons per-second = 1x10^9 which is a lot less than 1A.
A billion electrons per-second = 10^9/6.241x10^18 = 0.160nA = 160pA = 160x10^(-12) A (160 pico-amperes so pretty much the number in the article).
So while this might be a whole wack load electrons for this type of device it really is not much.
Also it might make you respect your hose wiring a little more.
Your 200A house service is (200*1A) = 1.2482x10^21 electrons per second.
Re:OMG, Maxwell's Demon! (Score:4, Informative)
The computation/observation needed for the demon to do his thing exceeds the energy made available by doing so.
Nice. Closer to absolute measurements. (Score:5, Informative)
The idea here is to define the ampere as N electrons per second. This may make that possible. The number is around 6.241 Ã-- 10^18 electrons per second. Direct counts of electrons allow a precise, repeatable way to define an amp.
The goal is to define the fundamental units from measurable properties of the universe, so that reproduceable standards can be constructed. That's been achieved for time and length, but not mass. You can buy an atomic clock that gets its time measurement from the definition of the second. (HP used to make those, but that business was sold off from Agilent in 2006.) There's a method with a Kr-86 light source and interferometers to count out a meter in wavelengths of light. But there's no corresponding standard for mass. Mass is tied to a physical 1Kg weight stored in France, and everything has to be traced back to that, with each successive derived standard kilogram a little less accurate.
A kilogram ought to be defined as N atoms of something, but atom counting isn't quite good enough yet. There's a plan to define mass through the Planck constant, which means tying the standard of mass to the standard of current.
Three fundamental units are sufficient to lock down all the other units, and this is a step towards doing that.
Re:1A = 6.241x10^18 electrons/second (Score:2, Informative)
Your house service is AC at a nice integer frequency, so you end up with 0 electrons per second.
Re:The last sentence (Score:3, Informative)
Sorry but no.
Ampers measures electric current flow.
Volts mesaures voltage potencial.
In some cases there is a relationship (by the means of an ideal source and an ideal resistor), but "Amps is dependent on voltage only in a specific case".