1. Probability of the local response caused by a delta-electrons on the axis of an ion track.
Ditlov V.A. Alikhanov Institute of Theoretical and Experimental Physics , Moscow, B. Cheremushkinskaya 25, Russia

2. Many-hit model
Here  – is the mean number of hits per one target. The realization of the case for the first three values  is shown
in Fig.There are left only the inactivated cells.
Restricted energy losses include only those d-electrons, whose energy w is less then some energy of cut off wcut It is supposed, that d-electrons with larger energy run far from track axis without any registration effect. But in reality remarkable part of d-electron return energy to the track axis vicinity after multiply scattering in the matter of the detector..

3. Distribution of developed grains over emulsion layer depth after exposures by electron flux with energy E=10 keV - curve 1 and E=500 keV – curve 2.

5. Role of returned d-electrons in energy losses at track axis comparing to their intial integral stopping power in detector CR-39.

6. Conclusions:
The calculation showed that role returning d-electrons In formation of
local response at track axis is significant.
2. For the cases when it is enough to know energy losses of d-electrons
at the axis formulae of Spencers became simpler.
3. In the regime of «grain density» we can use the frequency of effective
action in the next kind:
Where
is a registration parameter, which can
Be found from calibration.

7. Thank you for attention!