Matches in SemOpenAlex for { <https://semopenalex.org/work/W756589917> ?p ?o ?g. }
Showing items 1 to 75 of
75
with 100 items per page.
- W756589917 abstract "The uncertainty in the frequency of a linear-ion-trap frequency standard (LITS) can be reduced substantially by use of a very small magnetic inhomogeneity tailored to compensate for the residual second-order Doppler shift. An effect associated with the relativistic time dilatation, one cause of the second-order Doppler shift, is ion motion that is attributable to the trapping radio-frequency (RF)electromagnetic field used to trap ions. The second-order Doppler shift is reduced by using a multi-pole trap; however it is still the largest source of systematic frequency shift in the latest generation of LITSs, which are among the most stable clocks in the world. The present compensation scheme reduces the frequency instability of the affected LITS to about a tenth of its previous value. The basic principles of prior generation LITSs were discussed in several prior NASA Tech Briefs articles. Below are recapitulated only those items of basic information necessary to place the present development in context. A LITS includes a microwave local oscillator, the frequency of which is stabilized by comparison with the frequency of the ground state hyperfine transition of 199Hg+ ions. The comparison involves a combination of optical and microwave excitation and interrogation of the ions in a linear ion trap in the presence of a nominally uniform magnetic field. In the current version of the LITS, there are two connected traps (see figure): (1) a quadrupole trap wherein the optical excitation and measurement take place and (2) a 12-pole trap (denoted the resonance trap), wherein the microwave interrogation takes place. The ions are initially loaded into the quadrupole trap and are thereafter shuttled between the two traps. Shuttling ions into the resonance trap allows sensitive microwave interrogation to take place well away from loading interference. The axial magnetic field for the resonance trap is generated by an electric current in a finely wound wire coil surrounded by magnetic shields. In the quadrupole and 12-pole traps, the potentials are produced by RF voltages applied to even numbers (4 and 12, respectively) of parallel rods equally spaced around a circle. The polarity of the voltage on each rod is opposite that of the voltage on the adjacent rod. As a result, the amplitude of the RF trapping field is zero along the centerline and increases, with radius, to a maximum value near the rods." @default.
- W756589917 created "2016-06-24" @default.
- W756589917 creator A5037072496 @default.
- W756589917 creator A5038345376 @default.
- W756589917 date "2008-03-01" @default.
- W756589917 modified "2023-09-26" @default.
- W756589917 title "Magnetic Compensation for Second-Order Doppler Shift in LITS" @default.
- W756589917 hasPublicationYear "2008" @default.
- W756589917 type Work @default.
- W756589917 sameAs 756589917 @default.
- W756589917 citedByCount "0" @default.
- W756589917 crossrefType "journal-article" @default.
- W756589917 hasAuthorship W756589917A5037072496 @default.
- W756589917 hasAuthorship W756589917A5038345376 @default.
- W756589917 hasConcept C106289968 @default.
- W756589917 hasConcept C120665830 @default.
- W756589917 hasConcept C121099081 @default.
- W756589917 hasConcept C121332964 @default.
- W756589917 hasConcept C131221115 @default.
- W756589917 hasConcept C142757262 @default.
- W756589917 hasConcept C145148216 @default.
- W756589917 hasConcept C151730666 @default.
- W756589917 hasConcept C153294291 @default.
- W756589917 hasConcept C184779094 @default.
- W756589917 hasConcept C2779343474 @default.
- W756589917 hasConcept C27826464 @default.
- W756589917 hasConcept C39984356 @default.
- W756589917 hasConcept C44838205 @default.
- W756589917 hasConcept C62520636 @default.
- W756589917 hasConcept C83581075 @default.
- W756589917 hasConcept C86803240 @default.
- W756589917 hasConceptScore W756589917C106289968 @default.
- W756589917 hasConceptScore W756589917C120665830 @default.
- W756589917 hasConceptScore W756589917C121099081 @default.
- W756589917 hasConceptScore W756589917C121332964 @default.
- W756589917 hasConceptScore W756589917C131221115 @default.
- W756589917 hasConceptScore W756589917C142757262 @default.
- W756589917 hasConceptScore W756589917C145148216 @default.
- W756589917 hasConceptScore W756589917C151730666 @default.
- W756589917 hasConceptScore W756589917C153294291 @default.
- W756589917 hasConceptScore W756589917C184779094 @default.
- W756589917 hasConceptScore W756589917C2779343474 @default.
- W756589917 hasConceptScore W756589917C27826464 @default.
- W756589917 hasConceptScore W756589917C39984356 @default.
- W756589917 hasConceptScore W756589917C44838205 @default.
- W756589917 hasConceptScore W756589917C62520636 @default.
- W756589917 hasConceptScore W756589917C83581075 @default.
- W756589917 hasConceptScore W756589917C86803240 @default.
- W756589917 hasLocation W7565899171 @default.
- W756589917 hasOpenAccess W756589917 @default.
- W756589917 hasPrimaryLocation W7565899171 @default.
- W756589917 hasRelatedWork W142072244 @default.
- W756589917 hasRelatedWork W166019615 @default.
- W756589917 hasRelatedWork W1887934403 @default.
- W756589917 hasRelatedWork W2009027969 @default.
- W756589917 hasRelatedWork W2023899636 @default.
- W756589917 hasRelatedWork W2352747405 @default.
- W756589917 hasRelatedWork W2766313950 @default.
- W756589917 hasRelatedWork W2937146760 @default.
- W756589917 hasRelatedWork W29886757 @default.
- W756589917 hasRelatedWork W2989867066 @default.
- W756589917 hasRelatedWork W3009125792 @default.
- W756589917 hasRelatedWork W3020803941 @default.
- W756589917 hasRelatedWork W3024841439 @default.
- W756589917 hasRelatedWork W3101228223 @default.
- W756589917 hasRelatedWork W3172337677 @default.
- W756589917 hasRelatedWork W2110539046 @default.
- W756589917 hasRelatedWork W2245018386 @default.
- W756589917 hasRelatedWork W2292740277 @default.
- W756589917 hasRelatedWork W2874412713 @default.
- W756589917 hasRelatedWork W3146447833 @default.
- W756589917 isParatext "false" @default.
- W756589917 isRetracted "false" @default.
- W756589917 magId "756589917" @default.
- W756589917 workType "article" @default.