I'll admit to being a bit rusty in my particle physics, but since when do neutrons orbit the nucleus?
-Mike- On Mar 13, 2012, at 5:04 PM, David McQuate <[email protected]> wrote: > The article was accepted for publication on Feb 22, 2012 in Physical > Review Letters. > The March issue has already been published, so maybe this one will be in the > April issue. > > The title is > Single-ion nuclear clock for metrology at the 19th decimal place > > Authors: > C. J. Campbell, A. G. Radnaev, A. Kuzmich, V. A. Dzuba, V. V. Flambaum, and > A. Derevianko > > If you Google the title, I think you'll be able to find a pdf at > arxiv.org/pdf/1110.2490 > > The article discusses many factors necessary to obtain a fractional > inaccuracy approaching 1e-19. > The technique uses the 7.6 eV (ie 1.8377e15 Hz or 163 nm wavelength) nuclear > magnetic-dipole > transition in a single thorium 229 ion (3+). This paper does not report > experimental results--I don't > think the scheme has yet been implemented. > > "A pair of Th(3+) ions would be stored in a linear rf trap where strong rf > confinement places both ions > on the trap axis. With a trap of radius 700 um, and drive frequency of 25 > MHz..." > > The 163nm interrogation light "might be generated by a multi-stage > sum-frequency generation of > visible or NIR light within nonlinear crystals...with the fundamental > frequency locked to an ultra-stable > optical resonator." > > Laser cooling is used, using a 1088nm wavelength. The same wavelength is > used to suppress the > Stark effect by three orders of magnitude. > > Doppler shifts resulting from interrogation are reduced by alternating the > direction of the probe beam. > > A gravitational shift of 1e-19 will result from a difference in height of 1 > mm. > > A two week averaging time is suggested. > > Dave > wa8ywq > > On 3/13/2012 11:37 AM, Joseph Gray wrote: >> http://www.news.com.au/technology/sci-tech/nucelar-clock-100-times-more-accurate-than-atomic-clock/story-fn5fsgyc-1226297068083#ixzz1osFDYtyb >> >> I didn't see a link to a more detailed article. This one tells you >> almost nothing. >> >> Joe Gray >> W5JG >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
