# Presentation: 041567

## Atom Trap, Krypton-81, and Saharan Water

*Western Desert, Egypt*
*May, 2002*

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

## Radio-Carbon Dating

-  Widely applied
-  Limited to 50 kyr or younger

**Radio-Carbon Dating**

- 14C (t1/2 = 5730yr,  I.A.= 110-12)

## Radio-Krypton Dating

-        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

**Radio-Krypton Dating**

- 81Kr (t1/2 = 230kyr,  I.A.= 610-13)

## Low-Level Decay Counting (LLC)

- 81Kr (230 kyr) activity:   0.1 dpm/l Kr
- 85Kr (10.7 yr) activity:   3104 dpm/l Kr

## 85Kr 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)

- (t1/2 = 11 yr,  I.A.= 110-11)

## Accelerator Mass Spectrometry (AMS)

-  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)

- Advantages of atom counting:
-  Fast, Sensitive;  AMS / LLC = 105  (14C)
-  Not bothered by decay background

## Accelerator Mass Spectrometry of Kr-81

- 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-81**

- W. Kutschera *et al*., NIM B29, 241 (1994); P. Collon *et al*., NIM B123, 122 (1997)

## Laser Methods Based on Isotope Shifts

- Isotope shift due to the change in nuclear mass, charge radii and moments

## Resonance Ionization Spectroscopy (RIS)

**81****Kr**: Efficiency: >50%
-           Isotope Selectivity: 103-104
- S.D. Kramer *et al.*, Nucl. Instr. Meth. **B17**, 395(1986)

- V.S. Letokhov (Russia), G.S. Hurst (ORNL) 1970’s

## Photon Burst Spectroscopy

**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)

**Magneto-Optical Trap (MOT)**

**MOT Advantages**
-  Long observation time -- 100 ms;
-  High capture rate -- 109-1012 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

## Single Atom Detection

- <Single atom signal> = 1600 counts
- <Background> = 340  30 counts

**Single Atom Detection**

## Counting 81Kr and 85Kr

**Counting ****81****Kr and ****85****Kr**

## Atom Trap Trace Analysis (ATTA)

-  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)**

## Calibration: ATTA vs. Low-Level Counting

- X. Du *et al*., Geophys. Res. Lett. **30**, 2068 (2003)
- ATTA at Argonne, LLC at Bern

## 81Kr Abundance Measurements

**81****Kr Abundance Measurements**

-  Assumed identical trapping efficiency for 81Kr and 85Kr;
-  Need to calibrate ATTA efficiency with a 81Kr standard;
-  Atmospheric 81Kr is an integrator of cosmic-ray flux.

- (6.46  0.72)  10-13, LLC, H.H. Loosli and H. Oeschger, Ear Plan Sci Lett 7, 67 (1969)
- (4.33  0.29)  10-13, LLC, V.V. Kuzminov & A.A. Pomanski, Radiocarbon 22, 311 (1980)
- (5.3  1.2)  10-13, AMS, P. Collon et al., NIM B123, 122 (1997)
- (10  4)  10-13, ATTA, C.-Y. Chen et al., Science 286, 1139 (1999)
- (11.0  0.5)  10-13, ATTA, X. Du et al., Geophys Rev Lett 30, 2068 (2003)
- (4.8  1.0)  10-13, Theory, J. Masarik, private communication (2003)

## First Applications: Nubian Aquifer, Egypt

**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

**One Million Years of Nubian Aquifer Groundwater History**

- 33344 kyr

- 21242 kyr

- 39146 kyr

- 48845 kyr

- 67875 kyr

- N. C. Sturchio *et al*., Geophys. Res. Lett. **31**, 05503 (2004)

-  Groundwater at six sites dated;
-  Flow direction and speed measured;
-  Source determined.

**Uweinat **
**Uplift**

## ATTA Covered

## 81Kr Dating: From Dream to Practice

- Groundwater

- Polar Ice

## Halo Nucleus 6He

- Borromean Rings

## Search for EDM of 225Ra

- Advantages of an EDM measurement on 225Ra atoms in a trap
- In 225Ra the EDM effect is enhanced by ~102 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 225Ra atoms.
- Small sample in an UHV allows a high electric field (> 100 kV/cm).

- 225Ra
- Nuclear Spin = 1⁄2
- Electronic Spin = 0
- t1/2 = 15 days

- Proposed setup

## Argonne National Laboratory

- ATTA website:
- www-mep.phy.anl.gov/atta/
- Email:
- lu@anl.gov

## Trappable Atoms

- Transition Requirements:
-   Cycling transition
-   High transition rate (107 sec-1, allowed E1)
-   Practical wavelength ( > 200 nm)

**Trappable Atoms**

## Applicable Age Ranges (~ 0.1-10 t1/2) of Radionuclides

## A New Tool for Nuclear Physics Research and Beyond

## ATTA Analysis of 41Ca in Biomedical Samples

-     41Ca is an ideal tracer for studying calcium transport in bio-systems and for measuring bone-loss rates.

*I. D. Moore et al., Phys. Rev. Lett. ****92****, 153002 (2004)*

-  First demonstration of ATTA for 41Ca analysis;
-  Analyzed 41Ca/Ca ratios in biomedical samples.

## A Proving Ground for Nuclear Structure Theories

- 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**, 142501 (2004)

## First 81Kr-Dating of Old Groundwater

- P. Collon *et al*., Earth Planet Sci. Lett. **182**, 103 (2000)

**First ****81****Kr-Dating of Old Groundwater**

- AMS Counting Efficiency ~ 3  10-5

## 81Kr vs. 36Cl

- N. C. Sturchio *et al*., Geophys. Res. Lett. **31**, 05503 (2004)

## Krypton ATTA Setup

**Krypton ATTA Setup**

- 2.5 meters