Correlation of inflight neutron dosimeter and SEU measurements with atmospheric neutron model

Inflight measurements during high-altitude flight (NVB-57 and ER-2) of a simple neutron dosimeter, the PDM-303, correlate well with the NASA-Langley atmospheric neutron model. Based on simultaneous measurements with the much more accurate tissue equivalent proportional counter, the PDM-303 response has been calibrated in absolute terms for high-altitude flight. Thus the PDM-303 output is correlated with the fluence of atmospheric neutrons during flight from the NASA model. In addition, a compilation of single-event upsets in the autopilot of a commercial airliner are used to calculate the altitude variation of the atmospheric neutron flux, which agrees with the altitude variation predicted by the NASA atmospheric neutron model.