Rapid Light Manipulation Techniques for Collinear Laser Spectroscopy - PowerPoint PPT Presentation

Rapid Light Manipulation Techniques for Collinear Laser Spectroscopy and their Application for Neutron-Deficient Francium Annika Voss University of Jyväskylä Finland European Nuclear Physics Conference 2015 Groningen, NL

e Nuclear Laser Spectroscopic Landscape Status as of July 20th, 2015 Light Manipulation & n-def. Francium Annika Voss Unpublished data Published data Stable isotopes EuNPC 2015 Z=82 N=152 N=126 Z=50 Z=40 N=82 Z=28 Z=20 N=50 N=40 N=28 N=20

Nuclear Properties from Atomic Spectra Hyperfine Structures Light Manipulation & n-def. Francium Annika Voss static deformation Q dynamic deformation r sph Z r Q Electric quadrupole moment Q S Magnetic dipole moment Nuclear spin I EuNPC 2015 Isotope Shis → Changes in RMS charge radii δ ⟨ r 2 ⟩ Isotope 1 I = 0 δ ⟨ r 2 ⟩ A , A ′ ≈ δ ⟨ r 2 ⟩ A , A ′ sph · 5 sph + ⟨ r 2 ⟩ A ′ 4 πδ ⟨ β 2 2 ⟩ A , A ′ I = 0 Isotope 2 Counts Isotope 3 I > 1 / 2 Centroid Relative Frequency [MHz]

Nuclear Properties from Atomic Spectra Isotope Shis Light Manipulation & n-def. Francium Annika Voss static deformation Q dynamic deformation r Hyperfine Structures EuNPC 2015 → Changes in RMS charge radii δ ⟨ r 2 ⟩ Isotope 1 I = 0 δ ⟨ r 2 ⟩ A , A ′ ≈ δ ⟨ r 2 ⟩ A , A ′ sph · 5 sph + ⟨ r 2 ⟩ A ′ 4 πδ ⟨ β 2 2 ⟩ A , A ′ → Nuclear spin I I = 0 Isotope 2 → Magnetic dipole moment µ Counts → Electric quadrupole moment Q S Q 0 ≈ 5 Z ⟨ r 2 ⟩ sph √ ⟨ β 2 ⟩ (1 + 0 . 36 ⟨ β 2 ⟩ ) Isotope 3 I > 1 / 2 5 π Centroid Relative Frequency [MHz]

Nuclear Properties from Atomic Spectra Isotope Shis Light Manipulation & n-def. Francium Annika Voss Hyperfine Structures EuNPC 2015 → Changes in RMS charge radii δ ⟨ r 2 ⟩ Isotope 1 I = 0 δ ⟨ r 2 ⟩ A , A ′ ≈ δ ⟨ r 2 ⟩ A , A ′ sph · 5 sph + ⟨ r 2 ⟩ A ′ 4 πδ ⟨ β 2 2 ⟩ A , A ′ → Nuclear spin I I = 0 Isotope 2 → Magnetic dipole moment µ Counts → Electric quadrupole moment Q S Q 0 ≈ 5 Z ⟨ r 2 ⟩ sph √ ⟨ β 2 ⟩ (1 + 0 . 36 ⟨ β 2 ⟩ ) Isotope 3 I > 1 / 2 5 π Centroid δ ⟨ r 2 ⟩ → ⟨ β 2 2 ⟩ dynamic deformation Relative Frequency [MHz] Q 0 → ⟨ β 2 ⟩ static deformation

Hyperfine Pumping Spins: Light Manipulation & n-def. Francium Annika Voss high-spin multiplet I J . Relative intensities of individual HFS transitions: . EuNPC 2015 Selection Rules: I nuclear J electronic F J 208 Fr I = 7 F ′ = 17/2 15/2 7 2 P 3 / 2 13/2 total; ⃗ F = ⃗ I + ⃗ 11/2 100 55.3 S J,J ′ 22.5 → J ′ = 0 ∆ J = 0 , ± 1; J = 0 ✟ ❍ ✟ ❍ → F ′ = 0 F = ∆ F = 0 , ± 1; F = 0 ✟ ❍ ✟ ❍ 15/2 7 2 S 1 / 2 A B C 13/2 } 2 { F F ′ 1 S F , F ′ = (2 F + 1)(2 F ′ + 1) S J , J ′ , J ′

e Laser Spectroscopy Beamline @ T Annika Voss Light Manipulation & n-def. Francium EuNPC 2015 RFQ

Collinear Laser System for Intensity Modulation and Fast Frequency Switching Light Manipulation & n-def. Francium Annika Voss EuNPC 2015 Beam Pro fi ler Movable 7m Mirror to Beamline Intensity Modulation Focus & Power Adjustment, φ -EOM Beamline Injection 100m Fibre Link (single-mode) Blocked Path Monitor HeNe Faraday Isolator f1 ν -AOM f2 λ /4 Interference Filter ν -EOM IRIS Frequency Switching λ /2 λ -meter Fabry-Pérot Etalon Photodiode 300MHz M2 SolsTiS Lighthouse Frequency Stabilisation SPROUT

High-Frequency Intensity Modulation . Light Manipulation & n-def. Francium Annika Voss Voss et al. , 2013, Phys. Rev. Le. 111, 122501 . Voss et al. , 2013, PRL 111, 122501 EuNPC 2015 to data aquisition system 7 p 2 P 3/2 photomultiplier tube charge acceleration exchange electrodes uorescence cell + - photons + + + + ++ + + + + oo o oo + + o o + + ooo o oo o - + 7 s 2 S 1/2 counter-propagating hot alkali vapour ~40 cm laser beam or ~3 µs at E = 20 keV continuous photon stream 140 10 3 120 10 2 continuous Normalised count rate 100 Expected Intensity [%] 10 1 80 10 0 60 10 − 1 Transitions A & F 40 10 − 2 Transition B Transition C 20 10 − 3 Transition D Transition E 10 − 4 0 0 2 4 6 8 10 − 24500 − 24000 − 23500 − 23000 − 22500 − 22000 − 21500 Photon Scatters Frequency with respect to 208 Fr centroid [MHz]

High-Frequency Intensity Modulation . Light Manipulation & n-def. Francium Annika Voss Voss et al. , 2013, Phys. Rev. Le. 111, 122501 Voss et al. , 2013, PRL 111, 122501 . EuNPC 2015 to data aquisition system 7 p 2 P 3/2 photomultiplier tube charge acceleration exchange electrodes uorescence cell + - photons + + + + ++ + + + + oo o oo + + o o + + ooo o oo o - + 7 s 2 S 1/2 counter-propagating hot alkali vapour ~40 cm laser beam or ~3 µs at E = 20 keV photon pulse-train 140 10 3 120 10 2 continuous Normalised count rate 100 Expected Intensity [%] 10 1 80 10 0 modulated 60 10 − 1 Transitions A & F 40 10 − 2 Transition B Transition C 20 10 − 3 Transition D Transition E 10 − 4 0 0 2 4 6 8 10 − 24500 − 24000 − 23500 − 23000 − 22500 − 22000 − 21500 Photon Scatters Frequency with respect to 208 Fr centroid [MHz]

Rapid Frequency Switching Voss et al. , 2015, PRC 91, 044307 Light Manipulation & n-def. Francium Annika Voss Voss et al. , 2015, Phys. Rev. C 91, 044307 EuNPC 2015 to data f1 ν -AOM f2 λ /4 aquisition system photomultiplier IRIS tube charge acceleration exchange electrodes fluorescence cell - + photons + + + + ++ + + + + o oo o o oo + + + ooo + o o oo + - counter-propagating hot alkali vapour laser beam photon pulse-train 160 RF1, 90MHz 140 RF2, 100MHz RF3, 110MHz 120 Counts per 5ns 100 80 60 40 20 0 140 120 100 80 60 40 20 0 0 2 4 6 8 10 Time [ µ s]

Rapid Frequency Switching Voss et al. , 2015, PRC 91, 044307 Light Manipulation & n-def. Francium Annika Voss Voss et al. , 2015, Phys. Rev. C 91, 044307 EuNPC 2015 to data f1 ν -AOM f2 λ /4 aquisition system photomultiplier IRIS tube charge acceleration exchange electrodes fluorescence cell - + photons + + + + ++ + + + + o oo o o oo + + + ooo + o o oo + - counter-propagating hot alkali vapour laser beam photon pulse-train 160 RF1, 90MHz 140 0 . 6 RF2, 100MHz RF3, 110MHz 120 0 . 4 Counts per 5ns ν RF1 0 . 2 100 0 . 0 80 Count Rate 0 . 6 60 0 . 4 ν RF2 40 0 . 2 20 0 . 0 0 140 0 . 6 120 100 ν RF3 0 . 4 80 60 0 . 2 40 20 0 . 0 0 − 22800 − 22700 − 22600 − 22500 − 22400 0 2 4 6 8 10 Relative Frequency [MHz] Time [ µ s]

EuNPC 2015 7 . Mass gs m1 m2 206 3 10 Voss et al. , 2015, Phys. Rev. C 91, 044307 205 9/2 204 3 7 10 Annika Voss Light Manipulation & n-def. Francium . Fluorescence Spectra of 204,205,206 Fr 15 10 5 208 Fr m1 g m2 m2 g&m1 2 . 0 1 . 5 1 . 0 206 Fr Count Rate 0 . 5 1 . 2 0 . 8 205 Fr 0 . 4 1 . 2 m1 g m2 m2 g&m1 0 . 8 204 Fr 0 . 4 − 24000 − 22000 − 20000 − 18000 − 16000 − 12000 − 11000 − 10000 − 9000 13000 14000 15000 24000 26000 28000 30000 Relative Frequency [MHz] ⇒ First direct and unique spin determinations:

g -factors Voss et al. , 2013, Phys. Rev. Le. 111, 122501 & 2015, Phys. Rev. C 91, 044307 Light Manipulation & n-def. Francium Annika Voss Coc et al. ,1985, Phys. Le. B. 163, 66 EuNPC 2015 2 . 0 Coc g emp corresponding to Triumf [( π 1 h 9/2 ) ⊗ ( ν 3 p 3/2 )] 3 1 . 5 I=3 I=3 g -factor [( π 1 h 9/2 ) ⊗ ( ν 3 p 1/2 )] 5 1 . 0 [( π 1 h 9/2 )] 9/2 [( π 1 h 9/2 ) ⊗ ( ν 2 f 5/2 )] 7 I=7 I=7 0 . 5 [( π 1 h 9/2 ) ⊗ ( ν 1 i 13/2 )] 10 I=10 I=10 0 . 0 116 118 120 122 124 126 N

Changes in MS Charge Radii Voss et al. , 2013, Phys. Rev. Le. 111, 122501 & 2015, Phys. Rev. C 91, 044307 Light Manipulation & n-def. Francium Annika Voss Coc et al. ,1985, Phys. Le. B. 163, 66 (re-evaluated) EuNPC 2015 a) 0 . 00 | β 2 | = 0 . 20 0 . 15 0 . 10 0 . 0 − 0 . 1 δ � r 2 � N, 126 [fm 2 ] − 0 . 2 − 0 . 3 − 0 . 4 Pb gs Fr gs Fr m1 − 0 . 5 Fr m2 b) 0 . 01 ∆ [fm 2 ] 0 . 00 − 0 . 01 − 0 . 02 116 118 120 122 124 126 N

Summary individual analysis Light Manipulation & n-def. Francium Annika Voss neutron-deficient Fr isotopes and isomers spectroscopy on atomic species EuNPC 2015 spectroscopy neutron-deficient Fr and neutron-rich Rb ◦ developed fast-frequency intensity modulation for collinear laser ◦ successfully demonstrated suppression of hyperfine pumping on ◦ rapid frequency switching further enhances the technique ◦ coincidence methods allow the PMT signal to be disentangled for ◦ techniques may be applied at all facilities pursuing collinear laser ◦ first direct and model-independent nuclear spin determination for ◦ g -factors suggest strong mixing of shell-model states for ground states ◦ δ ⟨ r 2 ⟩ mark onset of deformation around N = 119 in Fr

ank you! Collaboration: (sorted by Number of Participants) Annika Voss Light Manipulation & n-def. Francium EuNPC 2015