Terrestrial Radiation Effects in ULSI Devices and Electronic Systems

Chapter 5Irradiation Test Methods for Single Event Effects

5.1 Field Test

SEEs (Single Event Effects) used to be mainly measured at avionics altitudes by in-flight tests because the radiation level is ×100 higher than that at ground level [1]. Even though the neutron flux level is high, adequate flight time is required to obtain statistically sound data, which results in costly experiments.

In the field test, on the other hand, DUTs (device under tests) are placed at a certain location with known latitude, longitude (and hence, geomagnetic latitude) and altitude, and the cost may be reasonable compared to in-flight tests. Since the terrestrial radiation strength is very low at sea level, it is necessary to expose thousands of DUTs to the field typically over several years. These types of tests, in principle, give straightforward and comprehensive results and, therefore, are referred to as real time tests. Nevertheless, care must be taken over the surrounding shielding conditions (buildings, floors), the Sun's activity and the atmospheric pressure that affects terrestrial radiation strength [2].

Attention has to be paid to space weather forecasts [3, 4] because a big solar flare may have a significant impact on the test results. GPS (Global Positioning System) data and neutron flux should be measured and recorded for an accurate analysis. In addition to the neutron flux data, the neutron energy spectrum may be measured by using the Bonner ball system [2] and the data is much ...