## 4 Test Process and Data Analysis
### SET Voltage Changes Induced by SPA and TPA  
The transient voltage response of the sensitive region Q20 at a 1064 nm light incident with the change in the laser energy is shown in Figure 7. At this wavelength, the single-event transient was mainly induced by SPA. Figure 5: Location distribution of the SET sensitive transistors of LM124. Figure 6: The response of the Q9 region to 1064 nm photons at different incident pulse energies. As can be seen from Figure 7, when the laser energy was 3.62 nJ, a negative transient voltage was observed, with an amplitude of about \(-\)1.8 V. When the laser energy was 15.84 nJ, a positive transient voltage was observed, and the amplitude of the transient voltage increased with the increasing laser energy. The transient voltage induced by the TPA technology under a 1260 nm light incidence of the sensitive region Q20 varied with the laser energy, as shown in Figure 8, below. As can be seen from Figure 8, under the TPA test technology, the first transient pulse was observed when the pulse laser energy was 1.70 nJ, and the amplitude was about \(-\)2.3 V with a negative polarity. Then, with the increasing pulse laser energy, the amplitude of the negative transient pulse decreased, and when the pulse laser energy was 3.61 nJ, the transient pulse became positive, and the amplitude of the transient pulse increased with the increasing pulse laser energy. The figure also shows a slope of the transient voltage of 1064 nm light when the laser energy was 17.17 nJ, which was induced by the SPA method at this time. It can be seen that the slope slopes of the transient voltage induced by SPA and TPA were consistent. Figure 8: The response of the Q20 region to 1260 nm photons at different incident pulse energies. Figure 7: The response of the Q20 region to 1064 nm photons at different incident pulse energies. By comparing Figures 6 and 7, above, it can be seen that the transient voltage slope slopes induced by SPA and TPA were basically the same. The energy of the SPA test with 1064 nm light induced a first transient voltage pulse of 3.62 nJ, while the energy of the TPA test with 1260 nm light induced a first transient voltage pulse of 1.70 nJ, which was about half that of the SPA test method. Meanwhile, in the case of the maximum transient voltage amplitude, the SPA pulse laser energy was about twice that of the TPA pulse laser energy, which further explains the difference between the results of the SPA and TPA tests. In addition, the same phenomenon was observed in the sensitive region R1 in the experiment. The transient voltage change in R1 under the incidence of 1064 nm light is shown in Figure 9, which shows the transient voltage induced by SPA. The pulse laser wavelength was 1064 nm. As can be seen from Figure 9, when the pulse laser energy was low, the transient voltage firstly appeared as a positive polarity pulse, followed by a small negative polarity pulse, and this situation continued until the pulse laser energy was about 6.45 nJ. Then, with the increasing pulse laser energy, the transient voltage pulse presented as a positive pulse with a larger amplitude, followed by a positive pulse with a smaller amplitude. When the pulse laser energy was greater than 18 nJ, the transient voltage pulse appeared as a positive pulse, and its duration increased with the increasing laser energy. The variation in the transient voltage induced by TPA with laser energy used in the R1 region with the light incident at 1260 nm is shown in Figure 10, below. It can be seen that the results generated by TPA were basically consistent with those of SPA. As can be seen from Figure 10, the transient voltage slope slope induced by TPA was very similar to that induced by SPA, and there was only a difference in the pulse laser energy. By contrast, two-photon absorption can induce the single-event effect. Compared with the single-event effect induced by single-photon absorption, the slopes of the two single-event transient pulses were basically the same.