I was with my dad, David W. Allan, this past Father's Day. He is an atomic clock physicist (AllansTIME.com), who spent his professional career in Boulder, Colorado with the atomic clock team there at the National Institute of Standards and Technology (NIST, formerly NBS). During his 32 years at NBS/NIST, he and the Time and Frequency Division team were able to increase the accuracy of timekeeping by more than a factor of a 1000.
He now lives just north of me in Fountain Green, Utah, in a beautiful solar home he designed and built as a family project. Retired in '92, he is now more busy than ever, but enjoying the research that he is doing.
A couple of weeks ago he returned from Boulder from a week-long stint, during which he gave a lecture and got caught up to speed on the work being done amongst his colleagues there.
NIST has been a leader in precision time-keeping. They showed him their recent work that will increased time accuracy by yet another 100-fold.
Let me quote from his Father's Day message from him to me and my brother a couple of weeks ago, if I may indulge:
"As I mentioned to you, we just got back from a glorious week in Boulder. We got to meet a ton of friends and to get updated on the latest and greatest in atomic clock metrology. NIST just finished a 60-day evaluation of the most accurate atomic clock in the world.
"The current accuracy is +/- a second in 40 million years. And they now have an optical clock – not cesium, which is about 100 times better. Also saw their quantum computing work. They have to be the best division in all of the Dept. of Commerce:
"It was wonderful to see all this technical progress with great team work."
Time measurement is the most accurate measurement known to man, with an accuracy that amounts to less than +/- 80 picoseconds in a day (a picosecond is one million-millionth of a second). It is at the heart of the modern technology world, keeping the power grid in sync, airlines on course, cell phones connected, and the Internet operational. Modern timekeeping counts the vibrations of atoms, for example, as the "pendulum" by which they obtain accuracy.
Now, here is the punch line.
Recently I have been working with James Fauble to open source his Ion Source Beam Projector design, which he believes will extract energy for practical use. He has been trying to source some quadrupole magnets of a particular dimension to replicate his design, which he built previously. He has been having a hard time sourcing the quadrupole magnets, whereas it used to be much easier to find them. It costs as much as $5,000 USD to tool up to build them to spec.
Well, it so happens that quadrupole magnets were used in atomic clock metrology in the past. They now use a different, "fountain" technology, mentioned by my dad, above. Perhaps that is why it was easier for James to find them before, compared to now.
Here is the explanation my dad gave of the role of quadrupole magnets in atomic clock metrology.
"A quadrapole can be used as a quantum energy state selector. It acts like a lens. Instead of focusing light, a quadrapole focuses a desired quantum energy state. Like the lens has a gradient in the thickness of the glass -- symmetric about the center, so does a quadrapole generate magnetic or electric field gradient, where the adjacent poles are of opposite polarity. Once the desired energy state is focused -- into a cavity for example -- then the atom or molecule can be interrogated in order to deduce some natural frequency associated with a particular pair of quantum energy levels. This frequency is that measured for the photons that are either absorbed or emitted proportional to this quantum energy difference. It is this frequency that is used like a pendulum for an atomic clock." (-- David W. Allan; June 28, 2004)
My dad said he would check around to see if there might be some quadrupole magnets that can be borrowed for Fauble's project. It will not happen quickly, though, because he is tremendously busy with his present project. This should not be construed as an explicit endorsement by him of that project, as he has not had the time to study it carefully.