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Explore cutting-edge research on atom trapping techniques for fundamental interaction and nuclear structure studies. Learn about selectivity, control over internal and external degrees of freedom, and trace analysis applications in nuclear science.
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Fundamental interaction andnuclear structure studies withatom traps Peter Müller
Argonne Cold Atom Trappers Argonne Cold Atom Trappers From left to right: Z.-T. Lu, P. Mueller, I. Sulai, K. Bailey, M. Kalita, S.M. Hu,W. Williams, W. Jiang, T.P. O’Connor, J. Singh, R. Parker, M. Dietrich, R. Holt
Outline • Atom trapping 101 • Selectivity39Ar Trace Analysis • Resolution6,8He Charge Radius • Control over external degrees of freedom6He b-n correlation • Control over internal degrees of freedom225Ra permanent electric dipole moment
1 Force µ (fL-fA)2+(G/2)2 Spontaneous Scattering Light Force Resonance & Repetition Atom Laser Beam pg ~1.5 eV/c x 1x107/s pa ~75000 eV/c Resonance Requirement G ~ 10 MHz Scattering Rate µ Force fL = fA Laser Frequency fL
Doppler Cooling Atom Laser Beam Laser frequency red detuned • = 6 MHz TD = 0.1 mK
Magneto-Optical Trap Raab et al., Bell Lab & MIT, 1987
Trapping F = -kx Cooling F = -av Atom Velocity Magnetic Field B(x) fL(v) Doppler Shift fA(x) Zeeman Shift A Trap with Cooling
Magneto Optical Trap • Pros: • Cooling: Temperature < 1 mK, • high resolution • Long observation time: 100 ms – 20 s • Spatial confinement: trap size < 1 mm • single atom sensitivity • Selectivity via repeated excitation, isotope shifts, HFS no isotopic / isobaric interference • Cons: • Relatively feeble forces -> moderate trapping efficiencies • Need “cycling” transition -> not applicable for all elements
Trapped (-able) Elements “Radioactive” Atom Traps World Wide TRIUMF, Vancouver, Canada K, Rb: b-n correlation, heavy n search Fr: parity violation, anapole moments LBNL, Berkeley, USA Na:b-n correlation KVI, Groningen , Netherlands Ra: electric dipole moment Na: b-n correlation INFN, Legnaro, Italy Fr: parity violation Tohoku University, Sendai, Japan Fr: electric dipole moment (#207) USTC, Hefei, China Kr-85,81: trace analysis University of Hamburg, Germany Kr-85: trace analysis University of Heidelberg, Germany Ar-39: trace analysis
39Ar Atom Trap Trace Analysis • Argon-39 : • cosmogenic isotope • half-life = 270 years • 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
5p[5/2]3 811 nm 5s[3/2]2 Metastable Atom Trap Trace Analysis III “Life of a single atom” Trap loading rates 40Ar: ~ 3 x 1012 / s 38Ar: ~ 2 x 109 / s 39Ar: 1 in ~ 4 hrs * Kr-85
Depleted 39Ar/Ar < 1x10-16 39Ar at Parts-per-quadrillion Atmospheric 39Ar/Ar = 8x10-16 W. Jiang et al., PRL 106, 103001 (2011)
389 nm 1083 nm He level scheme 3 3P2 Spectroscopy389 nm 2 3P2 Trap1083 nm 23S1 11S0 Atom Trapping of 6He & 8He at GANIL Atom Trap Setup Single atom signal Helium Rates 6He 8He @ source 5x107 s-1 1x105 s-1 Efficiency = 1x10-7 @ trap 5 s-1 30 hr-1 One 6Heatom
6He & 8He RMS Charge Radii L.B. Wang et al., PRL 93, 142501 (2004) – He-6 P. Mueller et al., PRL99, 252501 (2007) – He-8 + V. L. Ryjkovet al., PRL 101, 012501 (2008):He-8 mass+ I. Sick PRC 77, 041302(R) (2008):He-4 Charge Radius + A. Ong, J.C. Berengut, V.V. Flambaum, PRC 82, 014320 (2010)
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)
Beta-Decay Study with Laser Trapped 6He • Simple … atom, nucleus, decay mode • Sensitive to tensor couplings 6He trapping rate of 2103 s-1 with 210-6 trapping efficiency -> da/a = 0.1% in ~4 week beam time • 6He yields: • CENPA: ~1109 s-1 with 7Li(d,3He)6He @ 5 pmA -> O. Naviliat-Cuncic, Fri., 11:10
Electric Dipole Moment (EDM) Violates Both P and T A permanent EDM violates both time-reversal symmetry and parity + + - T P - - + EDM Spin EDM Spin EDM Spin Neutron Quark EDM Physics beyond the Standard Model: SUSY, String… Diamagnetic Atoms (Hg, Ra) Quark Chromo-EDM Paramagnetic Atoms (Tl) Molecules (PbO,YbF) Electron EDM
EDM measurement on 225Ra Oven: 225Ra Transverse cooling Zeeman Slower Magneto-optical Trap (MOT) Optical dipole trap (ODT) EDM measurement • Why trap 225Ra atoms • Large enhancement: • EDM (Ra) / EDM (Hg) ~ 102 – 103 • Efficient use of the rare 225Ra atoms • High electric field (> 100 kV/cm) • Long coherence times (~ 100 s) • Negligible “v x E” systematic effect
50 cm ODT Shuttle ~ 30,000 226Ra atoms ~50 mK • atoms moved 50 cm • atom lifetime limited by vacuum ~ 10 s
Dipole trap hand off in EDM science chamber HV Electrodes Standing wave ODT Shuttle ODT
Oven: 225Ra Transverse cooling Zeeman Slower Magneto-optical trap 100 days 10 days 100 kV/cm 10% 100 s 10 s 106 104 Optical dipole trap dd = 3 ´ 10-28 e cm dd = 3 ´ 10-26 e cm EDM measurement EDM measurement on 225Ra Statistical uncertainty: Ra / Hg Enhancement factor ~ 102 -103 Best experimental limit: d(199Hg) < 3 ´ 10-29 e cm
“Radioactive” Atom Traps elaborate, but high precision tool tomanipulate radioactive isotopes high selectivity, sensitivity, resolution, and exquisite control of external and internal degrees of freedom (when you really need it)
Thank You! Ra-225:Z.-T. Lu, I. Ahmad, K. Bailey, M. Dietrich, R. J. Holt, J. P. Greene, P. Mueller, T. P. O’Connor, R. Parker, J. Singh, I. A. Sulai, W. L. Trimble, Physics Division, Argonne National Laboratory, M. Kalita,W. Korsch, University of Kentucky, Lexington He-6: P. Mueller, Z.-T. Lu, W. Williams, Physics Division, Argonne National Laboratory, A. Garcia, D. Hertzog, P. Kammel, R.G.H. Robertson, A. Knecht, D. Zumwalt, R. Hong, G. Harper, E.H. Swanson, University of Washington, Seattle, O. Naviliat-Cuncic, Michigan State University, X. Flechard, LPC Caen www.phy.anl.gov/mep/atta/ He-8: P. Mueller,K. Bailey, R. J. Holt, R. V. F. Janssens, Z.-T. Lu, T. P. O'Connor, I. Sulai, Physics Division, Argonne National Laboratory, USA, M.-G. Saint Laurent, J.-Ch. Thomas, A.C.C. Villari, J.A. Alcantara-Nunez, R. Alvez-Conde, M. Dubois, C. Eleon, G. Gaubert, N. Lecesne, GANIL, Caen, France, G. W. F. Drake, University of Windsor, Windsor, Canada, L.-B. Wang, Los Alamos National Laboratory, USA Ar-39: W. Jiang, W. Williams, K. Bailey, T. O’Connor, Z.-T. Lu, P.MuellerPhysics Division, Argonne National Laboratory, R. Purtschert, Institute of Physics, University of Bern, N. Sturchio, Department of Earth and Environmental Science, University of Illinois, A. Davis, Department of Geophysical Sciences, University of Chicago, S.M. Hu, B. Sun, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China