Energy and angular dependence of single event upsets in ESA SEU Monitor

Abstract

The new generation ESA SEU Monitor is first applied to beam verification of Beijing HI-13 Tandem accelerator according to the popularization need of Europe Space Agency and at the desire of contrast of domestic acceleraor with international accelerator. Heavy ion single event cross section of ESA SEU Monitor obtained at HI-13 is compared with those from European facilities. Beam homogeneity is also analyzed based on the SEU physical bitmap. The accuracy of heavy ion beam monitoring technique at HI-13 accelerator is verified. Through combining the heavy ion testing result with the data from the other test sites, it can be observed that the differences between SEU cross sections with different heavy ion energies of the same LET value can reach 1-3 orders of magnitude in the sub-threshold zone of single event upset cross section curve below the direct ionization LET threshold. The geometrical structure, critical charge and collection efficiency of sensitive volume are constructed on the basis of testing data and process information. The physical mechanism of energy effect on single event upsets in ESA SEU Monitor is revealed through using the Monte-Carlo calculation. Nuclear reactions between incident heavy ions and material atoms can account for single event upsets below the direct ionization LET threshold. The differences in nuclear reaction type and cross section between the diferent energy heavy ions and material atoms are the root cause of the difference among heavy ion SEU cross sections with different energies at the same LET value. On the other hand, SEU bitmap nonuniformity among different blocks in memory array and different orientation dices in ESA SEU Monitor is first reported when the heavy ion is incident at a tilting angle at the low LET value. The analysis of device layout and calculation verification can account for this phenomenon. The material of interlayer dielectric with the tilting ion passing through is different when heavy ion reaches the sensitive volume of memory blocks with different data. This leads to the difference between efficient LET values inside the sensitive volume for different data blocks. Eventually the sensitivity difference in single event upset among blocks with different data occures. The applications of ESA SEU Monitor in beam calibrating, tuning of domestic accelerator and single event effect test can be broadened further. Prediction method of space single event upset rate including heavy ion energy dependence and special angular dependence based on full-physical simulation should be developed in the future.