Skip to main content

Thank you for visiting nature.com. 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.

  • Letter
  • Published:

Measuring fast neutrons in Hiroshima at distances relevant to atomic-bomb survivors

An Addendum to this article was published on 22 July 2004

Abstract

Data from the survivors of the atomic bombs serve as the major basis for risk calculations of radiation-induced cancer in humans1. A controversy has existed for almost two decades, however, concerning the possibility that neutron doses in Hiroshima may have been much larger than estimated. This controversy was based on measurements of radioisotopes activated by thermal neutrons that suggested much higher fluences at larger distances than expected2,3,4,5,6. For fast neutrons, which contributed almost all the neutron dose, clear measurement validation has so far proved impossible at the large distances (900 to 1,500 m) most relevant to survivor locations6. Here, the first results are reported for the detection of 63Ni produced predominantly by fast neutrons (above about 1 MeV) in copper samples from Hiroshima. This breakthrough was made possible by the development of chemical extraction methods7,8 and major improvements in the sensitivity of accelerator mass spectrometry for detection of 63Ni atoms (refs 8–11). When results are compared with 63Ni activation predicted by neutron doses for Hiroshima survivors6, good agreement is observed at the distances most relevant to survivor data. These findings provide, for the first time, clear measurement validation of the neutron doses to survivors in Hiroshima.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Figure 1: Measured and calculated 63Ni produced in copper samples by the bomb neutrons in Hiroshima.

Similar content being viewed by others

References

  1. BEIR V Report. Health Effects of Exposure to Low Levels of Ionizing Radiation (National Academy Press, Washington DC, 1990)

    Google Scholar 

  2. Hoshi, M. et al. Europium-152 activity induced by Hiroshima atomic bomb neutrons: comparison with the 32P, 60Co, and 152Eu activities in Dosimetry System 1986 (DS86). Health Phys. 57, 831–837 (1989)

    CAS  PubMed  Google Scholar 

  3. Straume, T. et al. Neutron discrepancies in the DS86 Hiroshima dosimetry system. Health Phys. 63, 421–426 (1992)

    Article  CAS  Google Scholar 

  4. Shizuma, K. et al. Residual 152Eu and 60Co activities induced by neutrons from the Hiroshima atomic bomb. Health Phys. 65, 272–282 (1993)

    Article  CAS  Google Scholar 

  5. Shizuma, K. et al. Residual 60Co activity in steel samples exposed to the Hiroshima atomic-bomb neutrons. Health Phys. 75, 278–284 (1998)

    Article  CAS  Google Scholar 

  6. Roesch, W. C. (ed.) US-Japan Joint Reassessment of Atomic Bomb Radiation Dosimetry in Hiroshima and Nagasaki -Final Report (Radiation Effects Research Foundation, Hiroshima, 1987)

  7. Marchetti, A. A. et al. Ultra-separation of nickel from copper metal for the measurement of 63Ni by AMS. Nucl. Instrum. Meth. B 123, 230–234 (1997)

    Article  ADS  CAS  Google Scholar 

  8. McAninch, J. E. et al. Measurement of 63Ni and 59Ni by accelerator mass spectrometry using characteristic projectile X-rays. Nucl. Instrum. Meth. B 123, 137–142 (1997)

    Article  ADS  CAS  Google Scholar 

  9. Knie, K., Faestermann, T. & Korschinek, G. AMS at the Munich gas-filled analyzing magnet system GAMS. Nucl. Instrum. Meth. B 123, 128–131 (1997)

    Article  ADS  CAS  Google Scholar 

  10. Rugel, G. et al. Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory. Nucl. Instrum. Meth. B 172, 934–938 (2000)

    Article  ADS  CAS  Google Scholar 

  11. Rühm, W. et al. Accelerator mass spectrometry of 63Ni at the Munich tandem laboratory for estimating fast neutron fluences from the Hiroshima atomic bomb. Health Phys. 79, 358–364 (2000)

    Article  Google Scholar 

  12. Hashizume, T. et al. Estimation of the air dose from the atomic bombs in Hiroshima and Nagasaki. Health Phys. 13, 149–161 (1967)

    Article  CAS  Google Scholar 

  13. Nakanishi, T., Imura, T., Komura, K. & Sakanoue, M. 152Eu in samples exposed to the nuclear explosions at Hiroshima and Nagasaki. Nature 302, 132–134 (1983)

    Article  CAS  Google Scholar 

  14. Haberstock, G. et al. Accelerator mass spectrometry with fully stripped 36Cl ions. Radiocarbon 28, 204–210 (1986)

    Article  CAS  Google Scholar 

  15. Korschinek, G. et al. Accelerator mass spectrometry with completely stripped 41Ca and 53Mn ions at the Munich tandem accelerator. Nucl. Instrum. Meth. B 29, 67–71 (1987)

    Article  ADS  Google Scholar 

  16. Straume, T. et al. Use of accelerator mass spectrometry in the dosimetry of Hiroshima neutrons. Nucl. Instrum. Meth. B 52, 552–556 (1990)

    Article  ADS  Google Scholar 

  17. Kato, K. et al. Accelerator mass spectrometry of 36Cl produced by neutrons from the Hiroshima bomb. Int. J. Radiat. Biol. 58, 661–672 (1990)

    Article  CAS  Google Scholar 

  18. Rühm, W., Kato, K., Korschinek, G., Morinaga, H. & Nolte, E. 36Cl and 41Ca depth profiles in a Hiroshima granite stone and the dosimetry system 1986. Z. Phys. A 341, 235–238 (1992)

    Article  ADS  Google Scholar 

  19. Straume, T., Harris, L. J., Marchetti, A. A. & Egbert, S. D. Neutrons confirmed in Nagasaki and at the Army Pulsed Radiation Facility: implications for Hiroshima. Radiat. Res. 138, 193–200 (1994)

    Article  ADS  CAS  Google Scholar 

  20. Rühm, W. et al. The dosimetry system DS86 and the neutron discrepancy in Hiroshima—historical review, present status, and future options. Radiat. Environ. Biophys. 37, 293–310 (1998)

    Article  Google Scholar 

  21. Arakatsu, B. Collection of Investigative Reports on Atomic Bomb Disaster 34– (Science Council of Japan, Tokyo, 1953)

    Google Scholar 

  22. Yamasaki, F. & Sugimoto, A. Collection of Investigative Reports on Atomic Bomb Disaster 18–19 (Science Council of Japan, Tokyo, 1953)

    Google Scholar 

  23. Gritzner, M. L. & Woolson, W. A. in US-Japan Joint Reassessment of Atomic Bomb Radiation Dosimetry in Hiroshima And Nagasaki-Final Report Vol. 2 (ed. Roesch, W. C.) 283–292 (Radiation Effects Research Foundation, Hiroshima, 1987)

    Google Scholar 

  24. Barnes, I. L., Garfinkel, S. B. & Mann, W. B. Standardization of 63Ni by efficiency tracing. Int. J. Appl. Radiat. Isot. 22, 781–783 (1971)

    Article  Google Scholar 

  25. Marchetti, A. A. & Straume, T. A search for neutron reactions that may be useful for Hiroshima dose reconstruction. Appl. Radiat. Isotop. 47, 97–103 (1996)

    Article  CAS  Google Scholar 

  26. Straume, T., Marchetti, A. A. & McAninch, J. E. New analytical capability may provide solution to the neutron dosimetry problem in Hiroshima. Radiat. Prot. Dosim. 67, 5–8 (1996)

    Article  CAS  Google Scholar 

  27. Shibata, T. et al. A method to estimate the fast-neutron fluence for the Hiroshima atomic bomb. J. Phys. Soc. Jpn 63, 3546–3547 (1994)

    Article  ADS  CAS  Google Scholar 

  28. Johnson, J. O. (ed.) A User's Manual for MASH v.2.0–Monte Carlo Adjoint Shielding Code System Report ORNL/TM/11778/R2 (Oak Ridge National Laboratory, Oak Ridge, TN, 1999)

  29. Rose, P. F. (ed.) ENDF/B-VI Summary Documentation, Cross-Section Evaluation Group Report BNL-NCS-17541 (Nuclear Data Center, Brookhaven National Laboratory, Upton, NY, 1991)

  30. Feldman, G. J. & Cousins, R. D. Unified approach to the classical statistical analysis of small signals. Phys. Rev. D 57, 3873–3889 (1998)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

We thank I. Proctor and A. M. Kellerer for their essential support of this project. We also thank S. Fujita and K. Shizuma for providing copper samples for this study. We thank the following organizations for supporting this work: the US Department of Energy, the US National Academy of Sciences, the European Commission, the German Federal Ministry of Environment, Nature Conservation and Nuclear Safety.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to T. Straume.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Straume, T., Rugel, G., Marchetti, A. et al. Measuring fast neutrons in Hiroshima at distances relevant to atomic-bomb survivors. Nature 424, 539–542 (2003). https://doi.org/10.1038/nature01815

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature01815

This article is cited by

Comments

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.

Search

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