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The synchrotron light source BESSY consists of a 50 MeV microtron, a full energy synchrotron and a 1.9 GeV storage ring. The electron losses during injection causes electromagnetic cascades within the stainless steel of the vacuum system and the aluminum chambers of the undulators. The cascade-produced neutrons result from giant resonances, quasi-deuteron fissions and photo-pion productions. The cross sections of the evaporation reactions of neutrons are an order of magnitude higher than the cross sections of the latter two reaction channels. The energy distribution of the giant resonance neutrons has a maximum at about 1 MeV in comparison with 100 - 200 MeV of the high energy neutrons. At electron accelerators outside the shielding wall, half of the neutron dose is often determined by the more penetrating high energy part of the neutron fluence. We used the particle interaction and transport code FLUKA for the calculations of the energy distribution of both the fluence and the dose inside and outside the shielding wall for different realistic scenarios. From the integrated spectra we get the calibration factor to determine the total neutron dose from the measurements directly.
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