The sensitivity of future large-scale dark matter detectors may be limited byneutrons produced in detector components. For this reason it is important touse pure materials and estimate the background from this source. Neutrons areproduced via spontaneous fission and (a, n) reactions from U and Th traces inthe materials. To estimate neutron yields and spectra, the cross-sections of (a,n) reactions and probabilities of transitions to different excited states should beknown. In this work these cross-sections and probabilities are calculated usingEMPIRE-2.19 for some isotopes and compared to the experimental data. Theresults have been used to calculate neutron spectra from materials with thecode SOURCES4. We plan to create a database of the (a, n) cross sectionsand neutron spectra for materials used in dark matter detectors. This work ison-going as part of the EU FP6 programme ILIAS.
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