Dresden 2000 – wissenschaftliches Programm

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PV: Plenarvorträge

PV III

PV III: Plenarvortrag

Dienstag, 21. März 2000, 08:15–09:00, H 01

Neutron Dosimetry in Hiroshima - Open Questions and New Developments — •Werner Rühm — Strahlenbiologisches Institut, Ludwig Maximilians Universität München, Schillerstrasse 42, 80336 München

The follow-up of the A-bomb survivors in Hiroshima and Nagasaki has become the major source of information on the late effects of radiation exposures. The deduced risk estimates depend equally on the information of health effects and on the determination of the gamma-ray and neutron doses received by each individual in the cohort. Recently, it has been shown that results of thermoluminescence and neutron activation measurements performed on samples from Hiroshima do not fit to those predicted by the presently valid dosimetry system DS86, at large distances (>1000 m) from the hypocenter. This discrepancy casts doubts on the survivors’ estimated doses.

The present paper outlines the current situation. Consequences of potential neutron and gamma dose modifications on risk estimates are briefly discussed. Current efforts aim at the detection of ⁶³Ni which was produced via the reaction ⁶³Cu(n,p) ⁶³Ni by fast neutrons, to estimate neutron doses of the Hiroshima A-bomb at ground level. At the Garching Tandem Laboratory, Munich, new developments allow ultra-sensitive measurements of ⁶³Ni by means of accelerator mass spectrometry. First results obtained from Hiroshima samples are presented, and options for further investigations discussed.