Use of a Continuous Wave Laser and Pockels Cell for Sensitive High-Resolution Collinear Resonance Ionization Spectroscopy

Abstract

New technical developments have led to a 2 orders of magnitude improvement of the resolution of the collinear resonance ionization spectroscopy (CRIS) experiment at ISOLDE, CERN, without sacrificing the high efficiency of the CRIS technique. Experimental linewidths of 20(1) MHz were obtained on radioactive beams of francium, allowing us for the first time to determine the electric quadrupole moment of the short lived [t_{1/2}=22.0(5) ms] ^{219}Fr Q_{s}=-1.21(2) eb, which would not have been possible without the advantages offered by the new method. This method relies on a continuous-wave laser and an external Pockels cell to produce narrow-band light pulses, required to reach the high resolution in two-step resonance ionization. Exotic nuclei produced at rates of a few hundred ions/s can now be studied with high resolution, allowing detailed studies of the anchor points for nuclear theories.

Combined high-resolution laser spectroscopy and nuclear decay spectroscopy for the study of the low-lying states inFr206,At202, andLynch1, Cocolios2, Billowes3 et al. 2016Phys. Rev. CSelf Cite

“…Arrival of the 422.7 nm and 1064 nm laser-light pulses in the interaction region was controlled using a Quantum Composers QC9258 digital delay pulse generator. The optimum balance between linewidth and laser-ionization efficiency was obtained when the pulse length of the 422.7 nm resonant excitation step was 100 ns and the 1064 nm ionization step was delayed by 100 ns with respect to the start of the resonant pulse [24]. The power of the 422.7 nm and 1064 nm cw laser light entering the beamline was measured to be 25 mW and 8 W, respectively, enough to saturate both transitions.…”

“…The CRIS technique allows the study of the hyperfine structure of short-lived isotopes produced online, whereby using ground-state or isomer selective ionization as a purification step, decay spectroscopy can be performed in clean conditions [19]. The recent development of highresolution CRIS with chopped cw laser light [24] offers a greater precision on the hyperfine parameters and isotope shift, and provides a greater selectivity of the isomers for decay-spectroscopy studies. By using these developments at the CRIS experiment, we have been able to study the 3 (+) , 7 (+) , and 10 (−) states in 206 Fr.…”

Analysis of counting data: Development of the SATLAS Python package

“…203 Fr has a nuclear spin I = 9/2, and the atomic transition at 423 nm that couples an S 1/2 to a P 3/2 state was probed. For more details on this type of experiment see [24,25]. This gives rise to 6 possible hyperfine transitions between the levels.…”

Departure of microscopic friction from macroscopic drag in molecular fluid dynamics

“…The mass dependence may lead to the substantial effect when transient response against externally applied electric fields is involved, especially at the short time scales by high frequency AC signal such as in the cases of the Paul traps. 40,41 Besides the electric fields for the charged solutes or particles in general, thermophoresis is suggested as another example. [14][15][16][17] As it is driven by the temperature gradient, the detailed characteristics of thermal fluctuation can affect the phenomenon in a unique manner.…”