Applications of Accelerator Mass Spectrometry Walter Kutschera

1. Applications of Accelerator Mass Spectrometry Walter Kutschera Vienna Environmental Research Accelerator (VERA) Faculty of Physics – Isotope Research and Nuclear Physics University of Vienna, Austria Yerevan Physics Institute, Armenia 18 October 2013

2. Applications of Accelerator Mass Spectrometry (AMS) are based on the measurement of long-lived radionuclides by counting atoms rather than the radioactive decays. This allows one to measure radionuclide concentrations in the range from 10-12 to 10-16.

3. The World of Radionuclides (W.K. Nucl. Instr. Meth B 50 (1990) 252-261) 1981 7 radionuclides 10Be, 14C, 26Al, 32Si, 36Cl, 41Ca, 59Ni ~140 radionuclides with T1/2 > 1 yr 1996 +9 more 2008 + 17 more

4. The World of Radionuclides (W.K. Nucl. Instr. Meth B 50 (1990) 252-261) 1981 7 radionuclides 10Be, 14C, 26Al, 32Si, 36Cl, 41Ca, 59Ni ~140 radionuclides with T1/2 > 1 yr 1996 +9 more 2008 + 17 more 2013 +22 more total of 55 radionuclides

5. Accelerator Mass Spectrometry (AMS)for “all“ isotopes:10Be, 14C, 26Al, 36Cl, 41Ca, 55Fe, 129I, 182Hf, 210Pb, 210Bi, 236U, 293-244Pu, SHE, (H2)–, (43Ca19F4)– –, PIXE-ART, Nucl. reactions: 6,7Li Negative-Ion Sources 1996: 1st operation 2001: 1st upgrade 2007: 2nd upgrade Negative- Ion Mass Spectro- meter (keV) Stripping and Molecule Dissociation Positive- Ion Mass Spectro- Meter (MeV) Detector area

6. 3 MV, 200 m2 The minaturisation of AMS facilities M. Suter, H.-A. Synal et al., ETH/PSI Zürich 500 kV, 30 m2 200 kV, 7 m2 Figure from W.K., Int. J. Mass Spectrom. 242 (2005) 145

7. 3.0 m 2.5 m Bio-MICADAS(Mini Carbon Dating System) Vitalea Science, Davis CA, USA

8. Progress in carbon sample size and precision MethodSample mass Precision Age uncertainty (g carbon) (% of 14C/12C) (years) Beta counting 1 – 5 0.2 16 (1950) AMS (0.1 – 1)x10-3 0.3 25 (1980) AMS(2 – 5)x10-6 1 82 (2) (2010)

9. The seven domains of the environment Atmosphere (cosmic-ray interaction, trace gases) Biosphere (plants, animal,humans) Hydrosphere (oceans, lakes, rivers, groundwater) Cryosphere (polar ice sheets, glaciers) Lithosphere (rocks, soil, sediments) Cosmosphere (meteorites, lunar material) Technosphere (man-made materials and radionuclides)

10. Overview of research areas and the corresponding radionuclides, which are used with AMS in the seven domains of our environment at large (underlined radionuclides are man-made, [ ] means not yet feasible at natural abundance) DomainResearch areaRadionuclide Atmosphere Production of radionuclides by cosmic-ray interaction 10Be, 14C, 26Al, 32Si, 36Cl, 39Ar, 81Kr, 129I Chemistry and dynamics of CO,CO2, CH414C, 14C Mixing of stratospheric and tropospheric air 14C, 10Be Releases from nuclear industry 14C, 99Tc, 129I Fossil fuel effect, ‘dead‘ CO214C Bomb peak from nuclear weapons testing 14C Biosphere Radiocarbon dating in archaeology and other fields 14C Radiocarbon calibration (tree rings, corals,sediments,…) 14C Development of radiocalcium dating of bones 41Ca Bomb peak dating (forensic medicin, human DNA) 14C Microdosing for drug developent in the pharma industry 14C In vivo tracer studies in plants, animals, humans 14C, 26Al, 41Ca Hydrosphere Dating of groundwater (important freshwater source) 14C, 36Cl, 39Ar, 81Kr, 129I Global ocean currents 14C, 14C, 39Ar, 99Tc, 129I, 231Pa, 236U Plaleoclimatic studies in lake and ocean sediments 14C Cryosphere Paleoclimatic studies in polar ice sheets 10Be, 14C, 26Al, 36Cl, [81Kr] Paleoclimatic studies in glaciers 14C, 32Si Tracing solar variability in time (Greenland ice cores) 10Be, 14C, 36Cl Bomb peak record in recent ice 36Cl, 41Ca, 129I

11. DomainResearch areaRadionuclide Lithosphere Exposure dating of rocks (deglaciation, geomorphology) 10Be, 14C, 26Al, 32Si, 36Cl, 53Mn, Neutron dosimetry of Hiroshima bomb explosion 36Cl, 41Ca, 63Ni Neutron flux monitor in in uranium minerals 236U Paleoclimatic studies in loess 10Be, 14C Tectonic plate subduction studies 10Be Cosmosphere Cosmogenic nuclides in meteorites and lunar material 10Be,14C,26Al,36Cl,41Ca,53Mn,59Ni, 60Fe Live supernova remnants in terrestrial material 26Al, 60Fe, 244Pu, [146Sm, 182Hf, 247Cm] Stable trace isotopes in solar grains 194,195,196,198Pt Geochemical solar neutrino detection [99Tc, 205Pb] Search for superheavy elements in terrestrial material Eka-Th, Ds, Rg, Fl, Eka-Bi (A ~ 300) Search for exotic particles in Nature free quarks, strange matter, … Technosphere Half-life measurements of radionuclides 32Si,41Ca,44Ti,60Fe,79Se, 126Sn,146Sm Depth profiling in fusion wall 3H Possible fusion plasma thermometer 27Al(n,2n)26Al Reaction studies for nuclear astrophysics 14N(n,p)14C, 26Mg(p,n)26Al, 40Ca(α,γ)44Ti, 54Fe(n,γ)55Fe Reaction studies for fission reactors 209Bi(n,g)210mBi, 232Th(,n,3n)230Th, 232Th(n,3n)231Th(ß-)231Pa Nuclear safeguards 146Sm, 149Sm, 151Sm, 233U, 236U, 237Np, 239, 240, 241, 242, 244Pu

12. A basic problem in 14C dating is that an absolute age can only be obtained from the measured 14C/12C ratio if one knows the initial 14C/12C ratio

13. 14CO 14Ct = 14CO e-t 12 April 2007 Age determinations by radiocarbon content: Checks with samples of known age J. R. Arnold and W. F. Libby, Science 110 (1949) 678-680

14. Dendrochronology: Establishing an absolute time scale from overlapping tree ring patterns (Figure from E.M. Wild and W.K., Spektrum der Wissenschaft, Dec. 2011, p.48)

15. Variation of the 14C content in tree rings of known age Figure from P.J. Reimer et al., Radiocarbon 46 (2004) 1024 Reference value: 14C/12C = 1.2x10-12 12,000 10,000 7500 5000 2500 0 Years before present

16. 14C Dating and the Iceman “Ötzi“

17. Czech Republic Slowakia Germany Austria Switzerland Discovery of Ötzi Slowenia The European Alps Italy France

18. Bow Hans Kammerlander and Reinhold Messner, two famous mountaineers from South Tirol, view Ötzi on 21 September 1991, two days after his discovery (Figure from W.K., W. Müller, Nucl. Instrum. Meth. B 204 (2003) 705)

19. 14C dating of bone and tissue from the Iceman Ötzi at the AMS labs of Oxford and Zürich in 1992 Uncalibrated (radiocarbon) age: 4550 ± 19 yr BP (before present) Calibrated age range: 5300 to 5050 BP (Figure from W.K., W. Müller, Nucl. Instrum. Meth. B 40 (2003) 705)

20. 14C dating at VERA of various materials found at the Discovery site of the Iceman Ötzi,matching the date of the Iceman. (Figure from W. K., W. Müller, Nucl. Instrum. Meth. B 204 (2003) 705)

21. 14C dating at VERA of various materials found at the discovery site of the Iceman Ötzi,not matchingthe date of the Iceman. (Figure from W. K., W. Müller, Nucl. Instrum. Meth. B 204 (2003) 705)

22. 14N + n 14C + p 14CO2 Biosphäre (t1/2 = 5700 Jahre) Simplified picture of the main ocean currents transporting heat around the globe Illustration by Wally Broecker from the Lamont Doherty Earth Observatory, Columbia University, New York

23. The Ugly and the Beautiful: 14C Bomb Peak Dating of Human DNA

24. Cosmic rays (p) Atmosphere (N, O, Ar) n 14N → 14C + p n O2 14CO2 Plants+ Oceans (14C) Biosphere (14C) 14C production through cosmic rays and nuclear weapons testing

25. 14C Bomb Peak Natural 14C variations Variation of the 14C content in atmospheric CO2 during the last 4000 Years [Spalding et al., Cell 122 (2005) 133]

26. NTBT 1963 14C decay (t1/2 = 5700 a) Natural 14C level Long-term observations of 14C in atmospheric CO2 in the northern and in the southern hemisphere Levin and Hesshaimer, Univ. Heidelberg, Radiocarbon 42/1 (2000) 69

27. Retrospective Birth Dating of Cells in Humans Kirsty L. Spalding et al. Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm Cell, Vol. 122 (15 July 2005) 133-143

28. 14C in genomic DNA reflects the age of cells “Most molecules in a cell are in constant flux, with the unique exception of genomic DNA, which is not exchanged after a cell has gone through its last division. The level of 14C integrated into genomic DNA should thus reflect the level in the atmosphere at any given point, and we hypothesized that determination of 14C levels in genomic DNA could be used to retrospectively establish the birth date of cells in the human body.” K.L. Spalding et al., Cell 122 (15 July 2005) 133-143

29. Some facts about human DNA and 14C (A physicist’s view) Basic composition of DNA: Macromolecule with 3x109 basepairs Chem. sum formula per bp: C20H23N7O13P2 and C19H22N8O13P2 Molecular weight: ~630 daltons per base pair, total ~1.9x1012 Da Mass of DNA per cell: 2 DNA per cell = 2 x 3 pg = 6 pg Mass of carbon (40 wt% C): 2.4 pg Totel length of DNA per cell: 2 x 3x109 x (0.34 nm) = 2 m C atoms of DNA per cell:2 x 3x109 x (20 C) = 1.2x1011 C atoms 14C/12C: 1.2x10-12 DNA of 10 cells: ~1 14C atom 15 million cells: 1.5 million 14C atoms C from DNA of 15 million cells: ~36 µg C Total 14C detection efficiency: ~2%  ~ 30,000 14C atoms detected

30. Birth 14C dates from DNA extracted from the respective cells Spalding et al., Cell 122 (2005) 133

31. birth birth birth birth Cortical neurons and non-neuronal cells have different renewel rates Spalding et al., Cell 122 (2005) 133

32. birth Determination of the age of neocortical neurons Bhardwaj et al., PNAS 103 (2006) 12564

33. The human olfactory bulb project Jakob Liebl VERA, Vienna Peter Steier VERA, Vienna Olaf Bergmann Karolinska, Stockholm Kirsty Spalding Karolinska,Stockholm The technical challenge for the olfactory bulb project Only 2 to 5 µg carbon from DNA extracted from olfactory bulb cells were available. This is almost thousand times less than for standard 14C dating (~1 mg C). Therefore 14C AMS for µg-carbon samples had to be developed at VERA. The key task was the reduction of carbon background in every step from human sample taking to the 14C measurement.

34. Turnover of non-neuronal cells Limited production of neuronal cells after birth Bergman et al., The Age of Olfactory Bulb Neurons in Humans, Neuron 74 (2012) 634-639

35. Δ14C (‰) Birth date of individual Evidence for neurogenesis in the hippocampus (memory, learning, emotion) of adult humans from 14C measurements in neuronal DNA of 57 individuals Kirsty L. Spalding et al., Cell 153 (2013) 1219-1227

36. The search for superheavy nuclides in Nature

37. Early History of Superheavy Elements (SHE) In the late 1960s, shell model corrections of the liquid drop model led to a region of stability for superheavy elements: Myers & Swiatecky, Nilsson, Strutinsky, Nix, Möller, .... Island of superheavy elements (SHE) Sea of instabilty Gregory N. Flerov (1913-1990)

38. 0.06s 2.6 s 34 s 11 s Superheavy Elements? Upper end of the chart of Nuclides(Stoyer, Nature 442 (2006) 876

39. 14N + n 14C + p 14CO2 Biosphäre (t1/2 = 5700 Jahre) Extension of the periodic table of elements beyond element 103 by Glenn Seaborg (1969) How to search for superheavy elements in nature

40. 292Eka-Th Search for SHE nuclides in Nature Positive evidencefrom ICP-SF-MS: Marinov et al.,Jerusalem, 2007, 2009, 2010 UpperlimitsfromAMS: Lachner et al., Munich, 2008 Dellinger et al., VERA, 2010, 2011 Ludwig et al., Munich 2012 211,213,217,218Th: (1-10) x 10-11, <8 x 10-15 < 4 × 10-15 ~ 1× 10-12 < 5 × 10-13 < 6 × 10-14 < 7 × 10-16 < 2 × 10-15 < 3 × 10-16 (1-10) × 10-10 Modified picture from: M. Stoyer, Nature442 (2006) 876.

41. Conclusion • Accelerator Mass Spectromtry in general • • AMS is one of the most powerfull analytical tools to study our • environment at large. • 14C bomb peak dating of human DNA • • This method shows great promise to study neurogenesis in • the human brain. • • Other parts of the human body have been studied as well • (e.g.heart, fat cells). • Search for superheavy nuclides in Nature • • Is the absence of evidence, evidence of absence? • • Answers to this question can only be approached by improved • measurements and improved theoretical predictions (e.g. nuclear astrophysics, atomic physics, chemistry, half-lives)