Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Direct mass measurements above uranium bridge the gap to the island of stability


The mass of an atom incorporates all its constituents and their interactions1. The difference between the mass of an atom and the sum of its building blocks (the binding energy) is a manifestation of Einstein’s famous relation E = mc2. The binding energy determines the energy available for nuclear reactions and decays (and thus the creation of elements by stellar nucleosynthesis), and holds the key to the fundamental question of how heavy the elements can be. Superheavy elements have been observed in challenging production experiments2,3,4, but our present knowledge of the binding energy of these nuclides is based only on the detection of their decay products. The reconstruction from extended decay chains introduces uncertainties that render the interpretation difficult. Here we report direct mass measurements of trans-uranium nuclides. Located at the farthest tip of the actinide species on the proton number–neutron number diagram, these nuclides represent the gateway to the predicted island of stability. In particular, we have determined the mass values of 252-254No (atomic number 102) with the Penning trap mass spectrometer SHIPTRAP5. The uncertainties are of the order of 10 keV/c2 (representing a relative precision of 0.05 p.p.m.), despite minute production rates of less than one atom per second. Our experiments advance direct mass measurements by ten atomic numbers with no loss in accuracy, and provide reliable anchor points en route to the island of stability.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Cyclotron resonance curve of 253No2+.
Figure 2: Comparison of the mass values obtained in this work with the results of the latest atomic-mass evaluation.
Figure 3: Part of the chart of nuclides between uranium and element 118.


  1. Lunney, D., Pearson, J. M. & Thibault, C. Recent trends in the determination of nuclear masses. Rev. Mod. Phys. 75, 1021–1082 (2003)

    Article  ADS  CAS  Google Scholar 

  2. Hofmann, S. & Münzenberg, G. The discovery of the heaviest elements. Rev. Mod. Phys. 72, 733–767 (2000)

    Article  ADS  CAS  Google Scholar 

  3. Morita, K. et al. Experiment on the synthesis of element 113 in the reaction 209Bi(70Zn, n)278113. J. Phys. Soc. Jpn 73, 2593–2596 (2004)

    Article  ADS  CAS  Google Scholar 

  4. Oganessian Heaviest nuclei from 48Ca-induced reactions. J. Phys. G 34, R165–R242 (2007)

    Article  ADS  CAS  Google Scholar 

  5. Block, M. et al. Towards direct mass measurements of nobelium at SHIPTRAP. Eur. Phys. J. D 45, 39–45 (2007)

    Article  ADS  CAS  Google Scholar 

  6. Moeller, P. & Nix, J. R. Stability of heavy and superheavy elements. J. Phys. G 20, 1681–1747 (1994)

    Article  ADS  Google Scholar 

  7. Bender, M., Rutz, K., Reinhard, P.-G., Maruhn, J. A. & Greiner, W. Shell structure of superheavy nuclei in self-consistent mean-field models. Phys. Rev. C 60, 034304 (1999)

    Article  ADS  Google Scholar 

  8. Cwiok, S., Heenen, P.-H. & Nazarewicz, W. Shape coexistence and triaxiality in the superheavy nuclei. Nature 433, 705–709 (2005)

    Article  ADS  CAS  Google Scholar 

  9. Rainville, S. et al. A direct test of E = mc2 . Nature 438, 1096–1097 (2005)

    Article  ADS  CAS  Google Scholar 

  10. Bollen, G. et al. Experiments with thermalized rare isotope beams from projectile fragmentation: a precision mass measurement of the superallowed β emitter 38Ca. Phys. Rev. Lett. 96, 152501 (2006)

    Article  ADS  CAS  Google Scholar 

  11. Odom, B., Hanneke, D., D'Urso, B. & Gabrielse, G. New measurement of the electron magnetic moment using a one-electron quantum cyclotron. Phys. Rev. Lett. 97, 030801 (2006)

    Article  ADS  CAS  Google Scholar 

  12. Blaum, K. High-accuracy mass spectrometry with stored ions. Phys. Rep. 425, 1–78 (2006)

    Article  ADS  CAS  Google Scholar 

  13. Schweikhard, L. & Bollen, G. eds. Special issue on ultra-accurate mass determination and related topics. Int. J. Mass Spectrom. 251 (2–3) 85–312 (2006)

    Article  Google Scholar 

  14. Roosbroeck, J. V. et al. Unambiguous identification of three β-decaying isomers in 70Cu. Phys. Rev. Lett. 92, 112501 (2005)

    Article  Google Scholar 

  15. Block, M. et al. Discovery of a nuclear isomer in 65Fe with Penning trap mass spectrometry. Phys. Rev. Lett. 100, 132501 (2008)

    Article  ADS  CAS  Google Scholar 

  16. Neidherr, D. et al. Discovery of 229Rn and the structure of the heaviest Rn and Ra isotopes from Penning-trap mass measurements. Phys. Rev. Lett. 102, 112501 (2009)

    Article  ADS  CAS  Google Scholar 

  17. Martín, A. et al. Mass measurements of neutron-deficient radionuclides near the end-point of the rp-process with SHIPTRAP. Eur. Phys. A 34, 341–348 (2007)

    Article  ADS  Google Scholar 

  18. Weber, C. et al. Mass measurements in the vicinity of the rp-process and the νp-process paths with the Penning trap facilities JYFLTRAP and SHIPTRAP. Phys. Rev. C 78, 054310 (2008)

    Article  ADS  Google Scholar 

  19. Rauth, C. et al. First Penning trap mass measurements beyond the proton drip line. Phys. Rev. Lett. 100, 012501 (2008)

    Article  ADS  CAS  Google Scholar 

  20. Bollen, G., Moore, R. B., Savard, G. & Stolzenberg, H. The accuracy of heavy-ion mass measurements using time of flight-ion cyclotron resonance in a Penning trap. J. Appl. Phys. 68, 4355–4374 (1990)

    Article  ADS  CAS  Google Scholar 

  21. Chaudhuri, A. et al. Carbon-cluster mass calibration at SHIPTRAP. Eur. Phys. D 45, 47–53 (2007)

    Article  ADS  CAS  Google Scholar 

  22. Audi, G., Wapstra, A. H. & Thibault, C. The AME2003 atomic mass evaluation. Nucl. Phys. A 729, 337–676 (2003)

    Article  ADS  Google Scholar 

  23. Herzberg, R.-D. et al. Nuclear isomers in superheavy elements as stepping stones towards the island of stability. Nature 442, 896–899 (2006)

    Article  ADS  CAS  Google Scholar 

  24. Hessberger, F. P. et al. Nuclear structure investigations in the region of superheavy nuclei. Phys. At. Nucl. 70, 1445–1451 (2007)

    Article  CAS  Google Scholar 

  25. Sulignano, B. et al. Identification of a K isomer in 252No. Eur. Phys. J. A 33, 327–331 (2008)

    Article  ADS  Google Scholar 

  26. Ghiorso, A. et al. Isotopes of element 102 with mass 251 to 258. Phys. Rev. Lett. 18, 401–404 (1967)

    Article  ADS  CAS  Google Scholar 

  27. Mikheev, V. L. et al. Synthesis of isotopes of element 102 with mass numbers 254, 253, and 252. At. Energ. 22, 90–92 (1967)

    Article  CAS  Google Scholar 

  28. Bemis, C. E. et al. Fragment-mass and kinetic-energy distributions from the spontaneous fission of 252No. Phys. Rev. C 15, 705–712 (1977)

    Article  ADS  CAS  Google Scholar 

  29. Hessberger, F. P. et al. GSI experiments on synthesis and nuclear structure investigations of the heaviest nuclei. Eur. Phys. J. D 45, 33–37 (2007)

    Article  ADS  CAS  Google Scholar 

  30. Kaneko, K. et al. Shell gaps and pn pairing interaction in N = Z nuclei. Phys. Lett. B 671, 42–45 (2009)

    Article  ADS  CAS  Google Scholar 

Download references


We thank D. Lunney for help with the preparation of the manuscript. The project was supported in part by the German Federal Ministry of Education and Research, the Max-Planck Society, and the Helmholtz Association. D.R. acknowledges support from Junta de Andalucia.

Author Contributions M.B. and M.D. performed the data analysis. M.B., K.B. and L.S. prepared the manuscript. All authors helped to perform the experiment, discussed the results, and commented on the manuscript at all stages.

Author information

Authors and Affiliations


Corresponding author

Correspondence to M. Block.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Block, M., Ackermann, D., Blaum, K. et al. Direct mass measurements above uranium bridge the gap to the island of stability. Nature 463, 785–788 (2010).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing