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Ra-225: The Path to a Next Generation EDM Experiment Peter Mueller Argonne National Laboratory Supported by U.S. DOE, Office of Nuclear Physics.

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Presentation on theme: "Ra-225: The Path to a Next Generation EDM Experiment Peter Mueller Argonne National Laboratory Supported by U.S. DOE, Office of Nuclear Physics."— Presentation transcript:

1 Ra-225: The Path to a Next Generation EDM Experiment Peter Mueller Argonne National Laboratory Supported by U.S. DOE, Office of Nuclear Physics

2 Electric Dipole Moment (EDM) Violates Both P and T + - + - - + TP EDMSpinEDMSpinEDM Spin A permanent EDM violates both time-reversal symmetry and parity Neutron Diamagnetic Atoms (Hg, Ra) Paramagnetic Atoms (Tl) Molecules (PbO,YbF) Quark EDM Quark Chromo-EDM Electron EDM Physics beyond the Standard Model: SUSY, String…

3 EDM of Hg, Ra…, Dzuba, Flambaum, Ginges, Kozlov, PRA (2002) Schiff moment of 199 Hg, de Jesus & Engel, PRC (2005) Schiff moment of 225 Ra, Dobaczewski & Engel, PRL (2005) Fully self-consistent calculations…, Ban et al. (2010) Skyrme ModelIsoscalarIsovectorIsotensor SkM*110800160 SLy42302800400 Enhancement Factor: EDM ( 225 Ra) / EDM ( 199 Hg) EDM of 225 Ra enhanced: Large intrinsic Schiff moment due to octupole deformation; Closely spaced parity doublet; Relativistic atomic structure. Haxton & Henley (1983) Auerbach, Flambaum & Spevak (1996) Engel, Friar & Hayes (2000) EDM of 225 Ra enhanced       55 keV || || Parity doublet 225 Ra: Nuclear Spin = ½ Electronic Spin = 0 t 1/2 = 15 days

4 225 Ra Source 229 Th 7300 yr 225 Ra 15 days 225 Ac 10 days 209 Bi stable Fr, At, Rn… ~ 4 hours  Rare Isotope Facility Yield for 225 Ra ~ 10 10 - 10 12 s -1 2 mCi (or 60 ng) 225 Ra sources available from Oak Ridge National Lab -- competing with cancer therapies using 213 Bi, 225 Ac Test source: 300 nCi 226 Ra (1600 yr) -- invaluable for testing Ra(NO 3 ) 2 reduced by Ba metal and Al in 700 C oven

5 EDM measurement on 225 Ra Transverse cooling Oven: 225 Ra Zeeman Slower Magneto-optical Trap (MOT) Optical dipole trap (ODT) EDM measurement Statistical uncertainty: 100 kV/cm 10 s 10 4 10% 10 days  d = 3 x 10 -26 e cm Ra / Hg Enhancement factor ~ 10 2 -10 3  d( 199 Hg) = 1.5 x 10 -29 e cm

6 Single photon kick   v = 3 mm/s No repump, 20k cycles. With repump, 20M cycles. 714 nm, cycling, Ti:S ring laser 7s 2 1 S 0 7p 3 P 0  7p 3 P 1  7p 3 P 2  6d 3 D 1 6d 3 D 2 6d 3 D 3 6d 1 D 2 7p 1 P 1  420 ns 0.4 ms 6 ns 0.7 ms 1 70 1e-1 5e-4 2e-6 5e-2 2e-2 2e-3 7e-10 4e-5 6e-4 5e-2 2e-2 1429 nm, repump, diode laser Radium Atom Energy Level Diagram V. Dzuba, V. Flambaum et al., PRA 61 (2000) Linewidth ~ 400 kHz. k B T = h  Doppler cooling limit 7  K, 14 mm/s 483 nm 6  s

7 0.4 mm 3,000 trapped radium atoms Radium Atom Repump Dynamics 1429nm Repumping to 1 P 1 3P13P1 3P03P0 3D13D1 1.5 E3 9.9 E1 Laser-cooling 2000 cm -1 0 N( ) Blackbody spectrum @ 298K (k B T/hc) = 210cm -1 ) 2.2 E2 7.4 E1 3.4 E1 298 K thermal transition rates 0.6 ms 1S01S0 1P11P1 482nm

8 Optical Dipole Trap Fiber laser: = 1550 nm, Power = 40 Watts Focused to 100  m  trap depth 350  K EDM in an optical dipole trap v x E, Berry’s phase effects suppressed Cold scattering suppressed between cold Fermionic atoms Rayleigh scat. rate ~ 10 -1 s -1 ; Raman scat. rate ~ 10 -12 s -1 Conclusion: possible to reach 10 -30 e cm for 199 Hg ---- Fortson & Romalis, PRA (1999)

9 Radium trapping and measurements Magneto-optical trap (MOT) of radium realized [Guest et al. PRL 2007]; Key atomic properties determined; Lifetimes of 3 P 1 [Scielzo, PRA 2006] and 1 D 2 [Trimble, PRA 2009]; Optical dipole trap (ODT) of radium realized (2010); MOT to ODT transfer efficiency reaching 80%. Sideview MOT 0.4 mm Head-on view MOT & ODT 0.4 mm 3,000 atoms MOT ODT 0.04 mm

10 Radium EDM Setup 10W

11 B-Field: Shields, Coils, Magnetometers  -shields: Shielding factor = 2 x 10 4 Design Goal B = 10 mG Stability:< 1 ppm in 100 sec Uniformity:< 1% / cm B gradient < 10 μG/cm Rb cell magnetometer: Budker design

12 E-Field: 100 kV / cm -- Done. 20 kV over 2mm vacuum gap < 50 pA leakage currents observed

13

14 EDM measurement on 225 Ra Transverse cooling Oven: 225 Ra Zeeman Slower Magneto-optical trap Optical dipole trap EDM measurement Statistical uncertainty: 100 kV/cm 10 s 10 4 10% 10 days  d = 3 x 10 -26 e cm 100 s 10 6 100 days  d = 3 x 10 -28 e cm Phase II Ra / Hg enhance factor ~ 10 2 -10 3  d( 199 Hg) = 1.5 x 10 -29 e cm

15 Present trap scheme (total of 4 lasers) Trap laser: 714 nm (weak); One repump laser: 1428 nm (#1); External Rb cell magnetometers: 780 nm. 7p 1 P 1 Trap, 714 nm 7s 2 1 S 0 7p 3 P 1 420 ns 6 ns 6d 3 D 1 Pump #1 7p 1 P 1 Trap, 714 nm 7s 2 1 S 0 7p 3 P 1 6d 1 D 2 420 ns 430  s 6 ns 6d 3 D 2 6d 3 D 1 Pump #1 Trap, 483 nm Pump #2 Pump #3 Blue trap scheme (total of 8 lasers) First trap laser: 483 nm (strong); Second trap laser: 714 nm; 3 repumpers: 1428 nm, 1488 nm, 2.75  m; Laser trapped 171 Yb as co-magnetometer. 399 nm, 556 nm 100 times more trapped atoms; Improved control on systematics; EDM sensitivity: 10 -28 e-cm. Blue Trap Upgrade

16 I. A. Sulai, W. L. Trimble, R. H. Parker, K. Bailey, J. P. Greene, R. J. Holt, M. Kalita, W. Korsch, Z.-T. Lu, P. Mueller, and T. P. O’Connor Argonne & U Kentucky Argonne Atom Trappers

17 Rb Magnetometry Shields Rb Coil Rb B Ra-225 B

18 Blackbody repumping Repump OFF Repump ON 3P13P1 3P03P0 3D13D1 1.5 E3 9.9 E1 2.2 E2 7.4 E1 Repumping to 1 P 1 (482nm photon) Laser-cooling 3.4 E1 298 K thermal transition rates 654  s

19 EDM Systematics and noise Optical dipole trap Standing wave Linear polarization E parallel B E, B perpendicular to polarization Magnetic field monitor and control  -shields shielding factor = 2 x 10 4 B-gradient < 10 μG/cm B-instability < 1 ppm in 100 s B-field monitor and cancellation using magnetometers External Rb vapor cells, 5 cm away Co-trapped 171 Yb atoms, co-magnetometer and null-EDM, < 50  m apart Environmental sources MOT & Zeeman slower Leakage current between electrodes Motional field (1/c 2 v x E) Geometric phase E-quadrupole terms + incomplete E-reversal Trap location moves Cold collisions Current supply noise Optical dipole trap effects Zeeman-like light shift E1-M1 interference term Monitor and control Many reversals B field E field polarization detection phase

20 The Seattle EDM Measurement Courtesy of Michael Romalis The best limit on atomic EDM EDM ( 199 Hg) < 3 x 10 -29 e-cm Griffith et al., Phys Rev Lett (2009) E E 199 Hg stable, high Z, J = 0, I = ½, high vapor pressure +e -e cm Unit EDM

21 Table of Elements 1S01S0

22 Stern man Geiger counter Special thanks to our health physicists Paul Niquette and Lee Sprouse. Experiment seems feasible with modest (< 10 mCi) 225 Ra sources.

23 1P11P1 3D13D1 3/2 3/2 -> 3/2 3/2 -> 1/2 1/2 -> 3/2 1/2 -> 1/2 3/2 1/2 6999.83 cm -1 F 540(4) MHz 4196(2) MHz 7031(2) MHz ISOLDE: 4195(4) MHz* *Ahmad et al., Phys. Lett. 133B, 47 (1983) Ra-226Ra-225 226 Ra and 225 Ra Hyperfine constants and isotope shift on 3 D 1 - 1 P 1

24 6 He e 6 Li +  -  He Ra Kr Atom traps at Argonne Nuclear Structure New Standard Model New Standard Model Applications

25 Argonne National Laboratory Google: atom trap Email: lu@anl.gov


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