Methodology to compute neutron-Induced Alphas contribution on the SEU Cross section in sensitive RAMs

A methodology to quantify the single event upset (SEU) cross section in a simplified random access memory (RAM) device for neutron energy ranging from 10 MeV up to 150 MeV has been proposed and accounts for both heavy and light ions. Usual Monte Carlo method is shown to be suitable for the contribution of short range ions but not for long range ones such as alphas. An analytical approach to investigate the contribution of these long ranges particles on SEU cross section is given. It uses the efficient ions distribution which is the probability that a neutron produces an ion able to deposit a given energy over a given distance after a given range. Results show, for accurate calculations in sensitive RAMs, alphas might be considered up to 100 /spl mu/m from the sensitive volume.