Research Papers in Physics and Astronomy


Date of this Version

January 1970


Published in Nuclear Instruments and Methods 79 (1970), pp. 320-324. Copyright © North-Holland Publishing Co./Elsevier. Used by permission. Supported by the U. S. Atomic Energy Commission and the National Science Foundation.


A recent theory of particle tracks assumes that the probability P for grain development in nuclear emulsion depends on the local dose E of ionization energy deposited by secondary electrons (delta rays) in the neighborhood of the particle track. The response is assumed to be one of exponential survival; that is, if E0 is the dose for 37% survival, then P = 1 – exp (-E/E0). By calculation of the dose E(t) deposited at depth t in the emulsion by normally incident, monoenergetic electron beams, and applying the assumed dose-effect relationship, response curves giving blackness versus electron fluence are obtained, in terms of E0 and a second parameter combining the effects of the density of undeveloped grains, the developed grain size, densitometer optics, and light scattering. Calculated and measured curves are compared.

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