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![Page 1: Zheng-Tian Lu Physics Division, Argonne National Laboratory Department of Physics, University of Chicago Supported by Department of Energy, Office of Nuclear.](https://reader035.fdocuments.us/reader035/viewer/2022062619/5518b5ec550346881f8b5132/html5/thumbnails/1.jpg)
Zheng-Tian LuPhysics Division, Argonne National LaboratoryDepartment of Physics, University of Chicago
Supported byDepartment of Energy, Office of Nuclear Physics
National Science Foundation, Earth Science Division
JLab FEL – Opportunity for a New Generation of JLab FEL – Opportunity for a New Generation of
Ultrasensitive Trace Analyzer of Noble Gas Ultrasensitive Trace Analyzer of Noble Gas
IsotopesIsotopes
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Nobel Gas TracersNobel Gas Tracers
Half-life
Atmospheric isotopic abundance
Sources
85Kr 10.8 yr 2x10-11 Nuclear fuel reprocessing39Ar 269 yr 8x10-16 Cosmic-ray induced
reaction81Kr 229,000
yr
6x10-13 Cosmic-ray induced reaction
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• Polar Ice as a natural archive temperature precipitation gas composition volcanic eruption solar variability...
• Number of 81Kr atoms in 1 liter of : Air 20,000 Water 1,000 Ice 1,000
83Kr, 82Kr...
81Kr
Cosmicp, n
81Kr
Radio-Krypton DatingRadio-Krypton Dating81Kr ((t1/2 = 230kyr, I.A.= 6 x 10-13)
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National Superconducting Cyclotron Laboratory
Michigan State University
Full stripping at high energy (~ 4 GeV) for isobar separation: 81Kr36+ vs. 81Br35+.
Accelerator Mass Spectrometry of Kr-81Accelerator Mass Spectrometry of Kr-81W. Kutschera et al., NIM B29, 241 (1994); P. Collon et al., NIM B123, 122 (1997)
First 81Kr dating: groundwater in GAB-- P. Collon et al., EPSL 182, 103 (2000)
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Methods of Trace-Isotope Analysis at PPT LevelMethods of Trace-Isotope Analysis at PPT Level
Muller, Physics Today
AMS
ATTA
LLC – Low Level Decay Counting Willard Libby, Science (1949)
AMS – Accelerator Mass Spectrometry R. A. Muller, Science (1977) Nelson et al., Science (1977) Bennett et al., Science (1977)
ATTA – Atom Trap Trace Analysis Chen et al. Science (1999)
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Neutral Atom TrapSodium, NIST
Laser Trapping and Cooling - a quick primer
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"for development of methods to cool and trap atoms with laser light"
Steve Chu ClaudeCohen-Tannoudji
William Phillips
1997 Nobel Physics Laureates
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Discharge
Source
TransverseCooling
BeamChopper
2DFocusing
ZeemanSlower
MOT
CCDCamera
Atom Trap Trace Analysis of KryptonAtom Trap Trace Analysis of Krypton
5p[5/2]3
5s[3/2]2
4p6Ground-level
Metastable 40 sec
811 nm
10 eVelectron collision
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0.0 0.5 1.0 1.5 2.0 2.5
0
5
10
15
20
25
Background
One Atom 81Kr
Photon S
cattering R
ate (
kH
z)
Time (sec)
<Single atom signal> = 1600 counts<Background> = 340 30 counts
0 1 2 3 4 5
0
5
10
15
2081
Kr
Photo
n S
catt
. R
ate
(kH
z)
Time (min.)
0 5 10 15 20 25
0
5
10
15
20
25
One Atom
Background
83Kr
Flu
orescence (
kH
z)
Time (sec)
Single Atom DetectionSingle Atom Detection
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-1000 -800 -600 -400 -200 0 2000.0
0.1
0.2
0.3
84Kr
81Kr85Kr
86Kr82Kr
78Kr
80Kr83Kr
T
rap F
luo. (arb. unit)
0.0
0.2
0.4
0.6
0.8
1.0
83Kr
Trap F
luo.(
arb. units)
-150 -120 -90 -60 -30 0 30 60 90
05
101520253035
(0.5 hrs.)
85Kr
81Kr (3 hrs.)
Atom
Counts
Frequency Offset (MHz)
Counting Counting 8181Kr and Kr and 8585KrKr
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One Million Years of Nubian Aquifer Groundwater One Million Years of Nubian Aquifer Groundwater HistoryHistory
Sturchio et al., Geophys. Res. Lett. (2004)
• Groundwater at six sites dated;• Flow direction and speed measured;• Source determined.
Uweinat Uplift
33344 kyr
21242 kyr
39146 kyr
48845 kyr
67875 kyr
0.60.21.0 Myr
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8181Kr Dating: From Dream to Kr Dating: From Dream to PracticePractice
10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 1Efficiency
107 106 105 104 103 102 10 1
Water or IceSample Size (L)
Groundwater
Polar Ice
LLC1969
AMS1997
ATTA-11999
ATTA-22003
ATTA-32011
ATTA-1: Chen et al., Science (1999)
ATTA-2: Du et al., Geophys. Res. Lett. (2003)
ATTA-3: Jiang et al., Phys. Rev. Lett. (2011)
ATTA-4JLab FEL
Present Status of ATTA-3:
• Selectivity requirement: Done;
• Efficiency requirements: Practical, but far from perfection
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Advantages over the existing RF discharge method:•Improve efficiency
• Metastable production efficiency• Collimate atomic beam
•Reduce sample loss and contamination
ATTA-4 with JLab FELATTA-4 with JLab FEL
Optical production of Kr* via two-photon excitation: 124 nm + 819 nm
Young et al., J. Phys. B (2002)Ding et al. RSI (2007) 5s[3/2]0
2
4p6
Ground
Metastable
5p[3/2]2
124 nm
5s[3/2]01
819 nm
Proposal to determine two-photon excitation rate in Summer, 2011 Zheng-Tian Lu, William Williams (Argonne) Charles Sukenik, Grady White (ODU) Gwyn Williams, Michelle Shinn et al. (JLab)
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Kevin BaileyWei Jiang
Zheng-Tian LuPeter MuellerTom O’ConnorWill Williams
Argonne Atom Argonne Atom TrappersTrappers
ATTA TeamATTA Team
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CollaboratorsCollaborators
Neil C. Sturchio University of Illinois at Chicago
Andrew M. Davis University of Chicago
L. Young & R. Dunford Chemistry Division, Argonne
Shuiming Hu University of Science & Technology of China
B. Mack Kennedy Lawrence Berkeley National Lab
Roland Purtschert University of Bern
Charles Sukenik Old Dominion University