Abstract
ACCORDING to recent work1, X-ray-induced chromatid breaks in Tradescantia microspores are due to the simultaneous occurrence of about seventeen ionizations concentrated within the narrow section of a chromatid. Such clusters of ionizations can be produced by electrons with small kinetic energy, that is, by electrons approaching the end of their path through matter. It might be of interest, then, to determine how many clusters consisting of a given number of ionizations (n) are produced per unit volume and per roentgen ; or, which is equivalent, what fraction of all ionizations is concentrated in such clusters. For the sake of simplicity, a cluster will be arbitrarily assumed to consist of the last n ionizations produced by an electron at the end of its path. Accordingly, there will be as many clusters as there are electrons producing at least n ionizations along their entire path. Also for simplicity, the following calculation will be restricted to cases in which the number n is greater than 2 or 3, but is still so small that many clusters result from every photo- or Compton-electron released by X-rays.
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14 August 1943
An Erratum to this paper has been published: https://doi.org/10.1038/152186e0
References
Lea, D. E., and Catcheside, D. G., J. Genetics, 44, 216 (1942).
Bohr, N., Phil. Mag., 30, 606 (1916).
Bloch, F., Z. Physik, 31, 363 (1933).
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FANO, U. Production of Ion Clusters by X-Rays. Nature 151, 698 (1943). https://doi.org/10.1038/151698a0
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DOI: https://doi.org/10.1038/151698a0
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