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Laser Laboratory (-ies)

Laser Laboratory (-ies). Peter Müller. Oven: 225 Ra (+Ba). Transverse cooling. Zeeman Slower. EDM probe. Optical dipole trap. Search for EDM of 225 Ra. Advantages: Large enhancement: EDM(Ra) / EDM(Hg) ~ 200 – 2000 Efficient use of 225 Ra atoms

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Laser Laboratory (-ies)

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  1. Laser Laboratory (-ies) Peter Müller

  2. Oven: 225Ra (+Ba) Transverse cooling Zeeman Slower EDM probe Optical dipole trap Search for EDM of 225Ra • Advantages: • Large enhancement: • EDM(Ra) / EDM(Hg) ~ 200 – 2000 • Efficient use of 225Ra atoms • High electric field (> 100 kV/cm) • Long coherence times (~ 100 s) • Negligible “v x E” systematic effect

  3. Search forEDM of 225Ra ~ 1x104 226Ra atoms 2 mm gap > 100 kV/cm • Status: • Trapped 225Ra and 226Ra • EDM probing region constructed • 10-10 Torr, 100 kV/cm, 10 mG • Next steps: • Dipole trap transfer • Optical pumping and detection

  4. 81Kr / 39Ar Atom Trap Trace Analysis • Krypton-81 : • cosmogenic • half-life = 230 ka • 81Kr/Kr = 1 x 10-12 • Argon-39 : • cosmogenic • half-life = 270 a • 39Ar/Ar = 8 x 10-16 • Dark Matter Searches : • LAr detectors (WARP, DEAP/CLEAN) • 39Ar major background • search for old / depleted Argon • Radio-Argon Dating : • 50 – 1000 year range • study ocean and groundwater • previously with LLC and AMS WIMP Argon Programme

  5. Atom Trapping & Nuclear Charge Radii of 6,8He Atom Trap Setup 389 nm 1083 nm 8He Spectroscopy Singleatomsignal He-6: L.-B. Wang et al., PRL 93, 142501 (2004)He-8: P. Mueller et al., PRL 99, 252501 (2007)

  6. Simulated time-of-flight signal New Physics Standard Model Beta-Decay Study with Laser Trapped 6He • 6He trapping rate: 1104 s-1, • 2105 coincidence events in 15 min: da = ± 0.008 • 1 week: da/a = 0.1% • 6He yields: • ATLAS: 1107 s-1 • CENPA: ~1109 s-1 • SARAF / SPIRAL2: ~11012 s-1

  7. Isotopic Menu for Laser Spectroscopy Low-energyyield, s-1 > 106 105 - 106 104 - 105 103 - 104 102 - 103 10 - 102 1 - 10 < 1 • Isotope shifts -> charge radii, deformations • Hyperfine structure -> moments (dipole,…) -> spin

  8. AC Laser Enclosure (~ 6’ x 10’) HEPA Laser Table (~ 3’ x 7’) Tape Station Ion Trap Collinear Beamline Laser Lab Layout @ CARIBU Cf-252 source 80 mCi -> 1Ci Gas catcher High-resolution mass separator dm/m > 1/20000 RF Cooler & Buncher … starting in fall 2010

  9. PMT / EMCCD Linear Paul Trap for Spectroscopy black, conductive coated electrodes ITO coated optics Ba+ • open geometry, linear Paul trap -> large light collection efficiency • buffer gas w. LN2 cooling, -> good spectroscopic resolution, quenching of dark states • -> few (single ?) ion detection sensitivity

  10. Ba Isotopes Ion Trap Spectroscopy at CARIBU Linear Paul trap for spectroscopy • Initially with neutron-rich Ba+ • Isotope shift + moments (HFS) • Use RF cooler / buncher & transfer line To investigate: • optimized trap geometry and detectionsystem • Buffer gas cooling + quenching (with H2) • Cooling of trap with LN2 Future: • other CARIBU beams • High mass: Pr, Nd, Eu, … • Low mass: Y, Zr, Nb, Sr, … • Yb+ -> No+ with ATLAS Upgrade

  11. Collinear Laser Spectroscopy • High spectroscopic resolution • High sensitivity through bunched beams • Neutral atoms w/charge-exchange • Measure for the first time: Rh, Ru, … • Extend isotopic chains on: Sn, Mo, Nb, … Other opportunities: • Laser polarized beams, e.g., Kr, Xe … • Laser polarization in matrix (solid noble gasses) • Resonance ionization to suppress isobars/isomers • … … 2011

  12. Isotopic Menu – “Low Mass” MOT Collinear N = 50 Refractoryelements N = 82

  13. Menu of Isotopes – “High Mass” MOT Collinear N = 82

  14. Ion beam Line for Laser Spec Setup StableSource@ +10/3 kV + 2.9 kV Fluor. Det. 50 kV X/Y Defl. Charge X Lens PDT 3 kV 3/10 kV 90 -5 kV PostAccel. 15 kV 9 ft

  15. Discussion Points • Need 1+ charge state for “heavy” isotopes • Operate buncher with neon

  16. Laser Spectroscopy of Refractory Elements Laser Spectroscopy of Cooled Zirconium Fission Fragments, P. Campbell et al., PRL 89, 082501 (2002) 101Zr • Measured 96–102Zr with yields > 500 s-1 -> @ CARIBU: 106Zr ~ 1x104 s-1 • N=60 shape transition for higher Z: Nb, Mo … -> 109Mo, 112Nb I = 3/2 Charge radius vs. deformation:

  17. t1/2=0.808 sec 0+ 6He b- E0=3.5097 MeV 1+ 100% 6Li Beta-Neutrino Correlation in the Decay of 6He Best experimental limit: a = - 0.3343 ± 0.0030 21Na Johnson et al., Phys. Rev. (1963)

  18. Thank You! 8He CollaborationK. Bailey, R. J. Holt, R. V. F. Janssens, Z.-T. Lu, P.M., T. P. O'Connor, I. SulaiPhysics Division, Argonne National Laboratory, USAM.-G. Saint Laurent, J.-Ch. Thomas, A.C.C. Villari, J.A. Alcantara-Nunez, R. Alvez-Conde, M. Dubois, C. Eleon, G. Gaubert, N. LecesneGANIL, Caen, FranceG. W. F. Drake - University of Windsor, Windsor, CanadaL.-B. Wang – Los Alamos National Laboratory, USA Argon Atom Trappers www.phy.anl.gov/mep/atta/

  19. Barium Ion Spectroscopy for EXO EXO Collaboration With He as buffer gas and repumping

  20. Collinear Laser Spectroscopy • Well adapted to on-line mass separators • Reduction of Doppler width: -> high resolution, high efficiency • Need >1000 ions/s for “good cases” with fluorescence detection • Higher efficiency with ion detection or decay counting • Charge exchange: neutral atoms + metastable states Ion beam ~ 50 keV HV

  21. Barium Quench Rate PRA 41, 2621 (1990)

  22. GFMC – Binding Energy vs. Charge Radius

  23. Atomic Energy Levels of Helium He energy level diagram 3 3P0,1,2 He discharge 3.2 eV389 nm 2 3P0,1,2 1.2 eV1083 nm 2 3S1 metastable 19.8 eV,e-collision in discharge 1 1S0

  24. CARIBU Layout Cf-252 source 80 mCi -> 1Ci Gas catcher High-resolution mass separator dm/m > 1/20000 Low Energy Experiments RF Cooler & Buncher Charge breeder

  25. Magneto-Optical Trap (MOT) • Cooling: Temperature~ 1 mK, • avoid Doppler shift / width • Long observation time: 100 ms • Spatial confinement: trap size < 1 mm • single atom sensitivity • Selectivity:no isotopic / isobaric interference Laser Cooling and Trapping Technical challenges: • Short lifetime, small samples (<106 atoms/s available) • Low metastable population efficiency (~ one in 100.000) • Precision requirement (100 kHz = Doppler shift @ 4 cm/s )

  26. GFMC – What happens to the a-core? AV18 + IL2 GFMC proton-proton distributions

  27. Collinear Laser Spectroscopy with Cold & Bunched Beams A. Nieminen et al., PRL 88, 094801 (2002) 174Hf Voltage, V • gate on ion bunch • reduce ion energy spread • increase S/N by ~ 102

  28. Laser Spectroscopy in Linear Paul Trap

  29. Laser Spectroscopy of Hf in Spherical Paul Trap 340 nm • H2 buffer gas • RF syncronized excitation and detection -> 1 GHz resolution W.Z. Zhao et al., Hyperf.Int.108,483 (1997)

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