0000000000324392
AUTHOR
F. Arbes
A simple method for counting the number of trapped ions in an ion trap
The number of stored Ca\(^+\) ions in an ion trap was measured optically by utilizing the metastable states. All the ions trapped are first pumped into the metastable \(D\) states. The ions in the metastable \(D\) states are transferred to the ground \(S\) state via the \(P\) state by exciting a \(D\rightarrow P\) transition. Each ion then emits one photon through a subsequent \(P\rightarrow S\) spontaneous emission. Thus, the number of photons is the same as the number of trapped ions initially in the metastable states. When a fraction of all the stored ions are pumped into the metastable states, the method is still applicable if the fraction of the ions is known.
Lifetime measurements of the 3D3/2 and 3D5/2 metastable states in CaII
The lifetime of the metastable 3D3/2 and 3D5/2 states of Ca+ ions is determined in a r.f. ion trap by laser excitation of this levels and subsequent time delayed probing of the state population by a second laser. In a buffer gas atmosphere of about 10−5−10−6 mbar of He we observe quenching to the ground state and strong finestructure mixing of the two D-states. This mixing allowes only the determination of the combined lifetime. Our result of τ(3D)=1.24(39) s is in good agreement with theoretical calculations.
On the possible determination of hyperfine anomalies by trapped ion spectroscopy
Abstract Laser-microwave double-resonance techniques in radiofrequency (rf) traps and Penning traps represent a powerful tool to determine hyperfine structure splittings as well as nuclear g factors to high precision. While hyperfine structure constants have been determined in a number of cases below the 10 −10 level of precision, electronic g factors have been measured to 10 −7 and there are good prospects of obtaining similar accuracy for g l . Moreover sensitive techniques have been developed for injection of ions from outside the trap. This opens the possibility to determine hyperfine anomalies at least to the 1% level of precision for chains of unstable isotopes.
Hyperfine structure andg-factor measurements in ion traps
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronicg-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10−6 and 5·10−7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Improved lifetime measurements of the 3D3/2 and 3D5/2 metastable states of Ca II
The lifetimes of both metastable 3D-levels of Ca+ have been measured using the ion storage technique. Operation at UHV-conditions eliminated the earlier reported problems of collisional finestructure mixing between those states [1], which is inherent to measurements at buffergas background. The results of τ(D 3/2)=1113(45) ms and τ(D 5/2)=1054(61) ms improve our earlier result [1] by almost one order of magnitude and are in good agreement with recent theoretical calculations [3, 4, 5].
Precise determination of the ground state hyperfine structure splitting of43Ca II
We have performed a laser microwave double resonance experiment on43Ca+ ions stored in a Paul ion trap. The ground state hfs splitting has been determined to Δν=3 225 608 286. 4(3) Hz. The value is corrected for small Zeeman, Stark and second order Doppler shifts as well as for light shift effects caused by the laserfields. The uncertainty is mainly determined by the errors of these corrections.