Atom Trap, Krypton-81, and Saharan Water Western Desert, Egypt May, Kr dating Earlier Methods Atom Trap Trace Analysis (ATTA) Nubian Aquifer, Egypt Supported by DOE, Office of Nuclear Physics NSF, Earth Science Division

Widely applied Limited to 50 kyr or younger 14 N 14 C 14 CO 2 14 CO Cosmic neutrons Radio-Carbon Dating Willard Frank Libby University of Chicago 1960 Nobel Prize in Chemistry Arnold&Libby, Science 110, 678 (1949) 14 C (t 1/2 = 5730yr, I.A.= )

Polar Ice as a natural archive temperature precipitation gas composition volcanic eruption solar variability... Number of 81 Kr atoms in 1 liter of : Air 20,000 Water 1,000 Ice 1, Kr, 82 Kr Kr Cosmic p, n 81 Kr Radio-Krypton Dating ( 81 Kr (t 1/2 = 230kyr, I.A.= )

Low-Level Decay Counting (LLC) 81 Kr (230 kyr) activity: 0.1 dpm/l Kr 85 Kr (10.7 yr) activity: dpm/l Kr 13.5 keV 2 liters of krypton, 100 hours Loosli and Oeschger EPSL 7, 67 (1969) Proportional counter Low-level lead

85 Kr in the Atmosphere Nuclear non-proliferation – Monitor fuel re-processing activities; Nuclear safety – Monitor leaks from nuclear fuel containers. F. Von Hippel, D.H. Albright, B.G. Levi, Scientific American 253, 40 (Sept., 1985) (t 1/2 = 11 yr, I.A.= )

Charge and mass measurements Particle identification based on energy loss Stripping eliminates molecular isobars Negative ion tricks eliminates atomic isobars Accelerator Mass Spectrometry (AMS) 14 N vs. 14 C R.A. Muller, Science 196, 489 (1977) D.E. Nelson et al., Science 198, 507 (1977) C.L. Bennett et al., Science 198, 508 (1977) R.A. Muller, Physics Today Advantages of atom counting: Fast, Sensitive; AMS / LLC = 10 5 ( 14 C) Not bothered by decay background - -

National Superconducting Cyclotron Laboratory Michigan State University Full stripping at high energy (~ 4 GeV) for isobar separation: 81 Kr 36+ vs. 81 Br 35+. Accelerator Mass Spectrometry of Kr-81 W. Kutschera et al., NIM B29, 241 (1994); P. Collon et al., NIM B123, 122 (1997)

Laser Methods Based on Isotope Shifts 1s 5 --2p 9 811nm Laser Frequency (MHz) Kr Kr-78 Isotope shift due to the change in nuclear mass, charge radii and moments Hypothetical Reality

Resonance Ionization Spectroscopy (RIS) 116 nm 558 nm 1064 nm 4p 6 4p 5 5s 4p 5 6p Kr 81 Kr: Efficiency: >50% Isotope Selectivity: S.D. Kramer et al., Nucl. Instr. Meth. B17, 395(1986) V.S. Letokhov (Russia), G.S. Hurst (ORNL) 1970s

Photon Burst Spectroscopy One-photon probability Four-photon probability G.W. Greenlees et al., Opt. Commun. 23, 236 (1977); V.I. Balykin et al., JETP Lett. 26, 357 (1977)

Magneto-Optical Trap (MOT) MOT Advantages Long observation time ms; High capture rate s -1 ; Narrow linewidth -- Doppler broadening negligible; Spatial confinement -- trap size < 1 mm; Storage -- separation of loading and detection. E.L. Raab, M. Prentiss, A. Cable, S. Chu and D. Pritchard, Phys. Rev. Lett. 59, 2631 (1987)

Atom Trappers at Argonne

Krypton Atom Level Diagram 5p[5/2] 3 5s[3/2] 2 4p 6 Ground-level Metastable 40 sec 811 nm 10 eV electron collision

= 1600 counts = counts Single Atom Detection

Counting 81 Kr and 85 Kr

Present Status of ATTA-2: Selectivity requirement: Done; Efficiency requirements: Practical, but far from perfection. ATTA-1: C.Y. Chen et al., Science 286, 1139 (1999) ATTA-2: X. Du et al., Geophys. Res. Lett. 30, 2068 (2003) Atom Trap Trace Analysis (ATTA) Efficiency Water or Ice Sample Size (L) Groundwater Polar Ice ATTA ATTA LLC 1969 AMS 1997

Calibration: ATTA vs. Low-Level Counting X. Du et al., Geophys. Res. Lett. 30, 2068 (2003) ATTA at Argonne, LLC at Bern

81 Kr Abundance Measurements Assumed identical trapping efficiency for 81 Kr and 85 Kr; Need to calibrate ATTA efficiency with a 81 Kr standard; Atmospheric 81 Kr is an integrator of cosmic-ray flux. ( ) , LLC, H.H. Loosli and H. Oeschger, Ear Plan Sci Lett 7, 67 (1969) ( ) , LLC, V.V. Kuzminov & A.A. Pomanski, Radiocarbon 22, 311 (1980) ( ) , AMS, P. Collon et al., NIM B123, 122 (1997) (10 4) , ATTA, C.-Y. Chen et al., Science 286, 1139 (1999) ( ) , ATTA, X. Du et al., Geophys Rev Lett 30, 2068 (2003) ( ) , Theory, J. Masarik, private communication (2003)

Nubian Aquifer Area ~ 2 x 10 6 km 2 Volume ~ 5 x 10 4 km years of Nile discharge Age ~ 10 5 years First Applications: Nubian Aquifer, Egypt

Expedition Team Argonne National Laboratory: Z.-T. Lu, M. Sultan University of Bern: R. Purtschert, R. Lorenzo University of Illinois: N. Sturchio Ain Shams University: A. El Bedawy, Y. Dawood, B. El Kaliouby, A. Mohammed Egyptian Geological Survey: Z. El Alfy, Radwan

Well

Outgassing

Work at night

Sheesha

Sand Dune

One Million Years of Nubian Aquifer Groundwater History kyr kyr kyr kyr kyr N. C. Sturchio et al., Geophys. Res. Lett. 31, (2004) Groundwater at six sites dated; Flow direction and speed measured; Source determined. Uweinat Uplift

ATTA Covered

81 Kr Dating: From Dream to Practice Efficiency Water or Ice Sample Size (L) Groundwater Polar Ice LLC 1969 AMS 1997 ATTA-I 1999 ATTA-II 2003 ATTA-III ? Kr-ATTA version 3.0 Incremental improvements: Cool Kr* source to K; More laser power; Fancier techniques. Kr-ATTA version 4.0 Optical production of Kr* 124 nm nm L. Young et al., J. Phys. B 35 (2002) Kapteyn et al. 215 nm nm 5s[3/2] 0 2 4p 6 Ground Metastable 5p[3/2] nm 5s[3/2] nm 215 nm ATTA-IV ?

Halo Nucleus 6 He Borromean Rings

Search for EDM of 225 Ra Advantages of an EDM measurement on 225 Ra atoms in a trap In 225 Ra the EDM effect is enhanced by ~10 2 due to nuclear deformation. Trap allows a long coherence time (~ 300 s). Cold atoms results in a negligible v x E systematic effect. Trap allows the efficient use of the rare and radioactive 225 Ra atoms. Small sample in an UHV allows a high electric field (> 100 kV/cm). 225 Ra Nuclear Spin = ½ Electronic Spin = 0 t 1/2 = 15 days Proposed setup Atomic Beam Magneto-Optical Trap Transverse Cooling Oven 10 mCi 225 Ra sample CO 2 -Laser Optical Dipole Trap EDM-probing region

Argonne National Laboratory ATTA website: www-mep.phy.anl.gov/atta/

Transition Requirements: Cycling transition High transition rate (10 7 sec -1, allowed E1) Practical wavelength ( > 200 nm) Excite Decay Forbidden Trappable Atoms

Applicable Age Ranges (~ t 1/2 ) of Radionuclides Age Range (year) Tracers C 81 Kr, 36 Cl 39 Ar 85 Kr, 3 H/ 3 He Be Noble gas tracers: advantages and disadvantages Simple production, transport, and deposition processes. Long residence time in atmosphere uniform and constant abundance. percentages in atmosphere: Ar, 99%; Kr, 97.5%; 14 C, 2% Easy to extract from large environmental samples. Low concentration in samples. Extremely difficult to analyze.

A New Tool for Nuclear Physics Research and Beyond A tool for studying exotic nuclear structure Determined the charge radius of the lightest halo nucleus 6 He A tool for testing time-reversal symmetry Search for T-violating EDM in octupole deformed 225 Ra A tool for studying Earth climate history Realized radio-krypton dating of old groundwater A tool for nuclear safety and security Monitor environmental 85 Kr gas produced by nuclear fission A tool for medical diagnostics Monitor bone-loss rate with 41 Ca

ATTA Analysis of 41 Ca in Biomedical Samples 41 Ca is an ideal tracer for studying calcium transport in bio-systems and for measuring bone-loss rates. GI tract ECF Plasma Soft tissue Bone pools Dietary calcium UrineFeces 41 Ca labeled I. D. Moore et al., Phys. Rev. Lett. 92, (2004) First demonstration of ATTA for 41 Ca analysis; Analyzed 41 Ca/Ca ratios in biomedical samples.

Reaction collision Elastic collision Atomic isotope shift Cluster models No-core shell model Quantum MC Experiments Theories A Proving Ground for Nuclear Structure Theories L.-B. Wang et al., Phys. Rev. Lett. 93, (2004) First model- independent determination

P. Collon et al., Earth Planet Sci. Lett. 182, 103 (2000) Watson Creek( ) 10 5 yr Oodnadatta( ) 10 5 yr Duck Hole( ) 10 5 yr Raspberry Creek( ) 10 5 yr The Great Artesian Basin First 81 Kr-Dating of Old Groundwater 16,000 liters of water 0.5 ccSTP Kr ~ Kr Kr counts in 9 hours ChemitryAMS AMS Counting Efficiency ~

81 Kr vs. 36 Cl Systematic effect in 36 Cl dating Variations in deposition rates ~ factor of 5 Nucleogenic 36 Cl 35 Cl(n, ) 36 Cl, = 44 barn Dissolved mineral Cl N. C. Sturchio et al., Geophys. Res. Lett. 31, (2004)

Krypton ATTA Setup 2.5 meters One Yao long