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
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2. 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

3. |a |b EDM of 225Ra enhanced Parity doublet - = (|a - |b)/2
Nuclear Spin = ½
Electronic Spin = 0
t1/2 = 15 days
EDM of 225Ra 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)
- = (|a - |b)/2
+ = (|a + |b)/2
55 keV
|a
|b
Parity doublet
Enhancement Factor: EDM (225Ra) / EDM (199Hg)
Skyrme Model
Isoscalar
Isovector
Isotensor
SkM*
110
800
160
SLy4
230
2800
400
EDM of Hg, Ra…, Dzuba, Flambaum, Ginges, Kozlov, PRA (2002)
Schiff moment of 199Hg, de Jesus & Engel, PRC (2005)
Schiff moment of 225Ra, Dobaczewski & Engel, PRL (2005)
Fully self-consistent calculations…, Ban et al. (2010)

4. 225Ra Source Rare Isotope Facilityb a
a,b
229Th
7300 yr
225Ra
15 days
225Ac
10 days
Fr, At, Rn…
~ 4 hours
209Bi
stable
• 2 mCi (or 60 ng) 225Ra sources available from Oak Ridge National Lab
-- competing with cancer therapies using 213Bi, 225Ac
• Test source: 300 nCi 226Ra (1600 yr) -- invaluable for testing
• Ra(NO3)2 reduced by Ba metal and Al in 700 C oven
Rare Isotope Facility
Yield for 225Ra ~ s-1

5. Statistical uncertainty:
Transverse
cooling
Oven:
225Ra
Zeeman
Slower
Magneto-optical
Trap (MOT)
Optical dipole
trap (ODT)
EDM
measurement
EDM measurement on 225Ra
Statistical uncertainty:
100 kV/cm
10 s
104
10%
10 days
dd = 3 x e cm
Ra / Hg Enhancement factor ~
dd(199Hg) = 1.5 x e cm

6. Radium Atom Energy Level Diagram
6 ns
Radium Atom Energy Level Diagram
7p 1P1°
1e-1
V. Dzuba, V. Flambaum et al., PRA 61 (2000)
1429 nm, repump, diode laser
0.4 ms
Single photon kick  dv = 3 mm/s
No repump, 20k cycles.
With repump, 20M cycles.
6d 1D2
2e-6
6 ms
5e-2
7p 3P2°
5e-4
6d 3D3
483 nm
5e-2
2e-2
420 ns
7e-10 70
2e-2
7p 3P1°
6d 3D2
4e-5
2e-3 1
0.7 ms
714 nm, cycling, Ti:S ring laser
6e-4
6d 3D1
7p 3P0°
Linewidth ~ 400 kHz. kBT = hG
Doppler cooling limit 7 mK, 14 mm/s
7s2 1S0

7. Radium Atom Repump Dynamics
2000
cm-1
N()
Blackbody spectrum
@ 298K
(kBT/hc) = 210cm-1)
2.2 E2
7.4 E1
3.4 E1
298 K thermal
transition rates
1429nm
Repumping
to 1P1
482nm
3P1
9.9 E1
3D1
Laser-cooling
0.6 ms
1.5 E3
3P0
0.4 mm
3,000 trapped radium atoms
1S0

8. EDM in an optical dipole trap
Fiber laser: l = 1550 nm, Power = 40 Watts
Focused to 100 mm  trap depth 350 mK
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 ~ s-1
Conclusion: possible to reach e cm for 199Hg
---- 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 3P1 [Scielzo, PRA 2006] and 1D2 [Trimble, PRA 2009];
Optical dipole trap (ODT) of radium realized (2010);
MOT to ODT transfer efficiency reaching 80%.
MOT
0.4 mm
3,000 atoms
MOT & ODT
Head-on
view
Sideview
MOT 0.4 mm
ODT mm

10. Radium EDM Setup
10W

11. B-Field: Shields, Coils, Magnetometers
Design Goal
B = 10 mG
Stability: < 1 ppm in 100 sec
Uniformity: < 1% / cm
m-shields: Shielding factor = 2 x 104
Rb cell magnetometer: Budker design
B gradient < 10 μG/cm

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

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14. Statistical uncertainty:
Transverse
cooling
Oven:
225Ra
Zeeman
Slower
Magneto-optical
trap
Optical
dipole trap
EDM
measurement
EDM measurement on 225Ra
Statistical uncertainty:
100 kV/cm
10 s
104
10%
10 days
dd = 3 x e cm
100 s
106
100 days
dd = 3 x e cm Phase II
Ra / Hg enhance factor ~
dd(199Hg) = 1.5 x e cm

15. Blue Trap Upgrade Present trap scheme (total of 4 lasers)
7p 1P1
Trap, 714 nm
7s2 1S0
7p 3P1
420 ns
6 ns
6d 3D1
Pump #1
6d 1D2
430 ms
6d 3D2
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 mm;
Laser trapped 171Yb as co-magnetometer.
399 nm, 556 nm
100 times more trapped atoms;
Improved control on systematics;
EDM sensitivity: e-cm.
Present trap scheme (total of 4 lasers)
Trap laser: 714 nm (weak);
One repump laser: 1428 nm (#1);
External Rb cell magnetometers: 780 nm.
Too full, reduce info on transitions

16. M. Kalita , W. Korsch, Z.-T. Lu, P. Mueller, and T. P. O’Connor
Argonne Atom Trappers
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

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

18. 3P1 3D1 3P0 Blackbody repumping 654 s Repump OFF Repump ON Repumping
to 1P1
(482nm photon)
Laser-cooling
3.4 E1
298 K thermal
transition rates
654 s

19. EDM Systematics and noise
Environmental sources
MOT & Zeeman slower
Leakage current between electrodes
Motional field (1/c2 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
Optical dipole trap
Standing wave
Linear polarization
E parallel B
E, B perpendicular to polarization
Magnetic field monitor and control
m-shields shielding factor = 2 x 104
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 171Yb atoms, co-magnetometer and null-EDM, < 50 mm apart
Many reversals
B field
E field
polarization
detection phase
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20. The Seattle EDM Measurement
199Hg stable, high Z, J = 0, I = ½, high vapor pressure E E
Courtesy of Michael Romalis
The best limit on atomic EDM
EDM (199Hg) < 3 x e-cm
Griffith et al., Phys Rev Lett (2009) +e -e cm
Unit
EDM

21. Table of Elements
1S0

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

23. 226Ra and 225Ra Hyperfine constants and isotope shift on 3D1 - 1P1
3/2 -> 3/2
Ra-226
Ra-225 F
540(4) MHz
1P1
3/2
1/2
4196(2) MHz
ISOLDE: 4195(4) MHz*
cm-1
3/2
3D1
1/2 -> 3/2
3/2 -> 1/2
1/2 -> 1/2
1/2
7031(2) MHz
*Ahmad et al., Phys. Lett. 133B, 47 (1983)

24. Atom traps at Argonne He Ra Kr q ne b 6He 6Li Nuclear New Standard
Structure
New Standard
Model He Ra Kr
6He ne
6Li + b - q
New Standard
Model
Applications 24

25. Argonne National Laboratory
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