SLVK300 May 2026 AFE7950-SEP

7 Single-Event Effects (SEE)

Single Event Upsets

Deviations in AC performance of the RX channel were used as a figure of merit for SEU. SNR degradation was treated as the main indicator of an upset to the AFE7950-SEP. Prior to an SEU beam run, the AFE7950-SEP was power-cycled, programmed, and baseline FFTs were stored for all RX and TX channels. When the SNR noise floor degraded from the baseline of 100dB, the beam stops and device is re-programmed (no power cycle involved) and have the fluence recorded. To determine the correlation between channels, a snapshot of the status of all the channels was recorded when RX channel 1 recorded an SEU event. Figure 7-1 shows the summary of what other channels failed at end of run.

Figure 7-1 State of Channels Post Beam

Table 7-1 SEU Runs

Run Number	Ion	LETEFF (MeV∙cm²/mg)	Fluence (ions/cm²)	Flux (ions/[cm²·s])	Uniformity	Run Time (s)	Cross Section (cm²)
1	Ag	57.73	3.89 × 10³	9.71 × 10²		40.06	1.31 × 10^-4
2		57.73	1.67 × 10⁴	9.58 × 10²		174.00
3		57.73	3.79 × 10⁴	9.047 × 10²	97.00	418.88
4		57.73	1.97 × 10⁴	8.83 × 10²	98.00	223.35
5		57.73	1.47 × 10⁴	9.83 × 10²	98.00	149.28
6		57.73	1.02 × 10⁴	8.75 × 10²	98.00	117.00
7		57.73	1.13 × 10⁴	1.17 × 10²	95.00	96.25
8		57.73	6.67 × 10³	1.22 × 10²	95.00	54.37
9		57.73	3.98 × 10³	1.21 × 10²	96.00	32.83
10		57.73	1.46 × 10⁴	1.23 × 10²	97.00	118.66
1	Cu	24.54	1.71 × 10⁴	1.25 × 10²	92	137.08	6.86 × 10^-5
2		24.54	2.14 × 10⁴	1.14 × 10²	94	167.9
3		24.54	2.75 × 10³	1.08 × 10²	95	25.31
4		24.54	9.65 × 10⁴	1.10 × 10²	91	877.87
5		24.54	1.31 × 10⁴	1.05 × 10²	90	124.68
6		24.54	2.60 × 10⁴	1.06 × 10²	94	244.22
7		24.54	3.46 × 10⁴	1.35 × 10²	100	255.88
8		24.54	9.20 × 10³	1.37 × 10²	95	67.25
9		24.54	1.37 × 10⁴	1.34 × 10²	93	102.37
10		24.54	1.94 × 10⁴	1.57 × 10²	97	123.42
11		24.54	3.34 × 10⁴	1.55 × 10²	97	215.81
1	Ar	9.75	6.17 × 10⁴	1.20 × 10²	94.00	557.00	4.98 × 10^-5
2		9.75	2.52 × 10⁴	1.17 × 10³	95.00	22.00
3		9.75	4.89 × 10⁴	1.16 × 10³	95.00	42.08
4		9.75	9.44 × 10⁴	1.25 × 10³	94.00	75.40
5		9.75	1.82 × 10⁴	1.18 × 10³	95.00	15.50
6		9.75	1.34 × 10⁴	1.24 × 10³	95.00	10.78

Single-Event Functional Interrupts

The single events that needed power cycling and reprogramming were classified as a SEFI event. Our procedure for recording SEFIs was to run the beam for a predetermined amount of time based on the flux level. The typical time period was five minutes for a flux of 1E2. At the end of the interval, the beam was paused and the device was reprogrammed to the original state. If the RX channel 1 SNR came back to a SNR noise floor of 100dB, the beam continues for the next period of time. If the noise floor did not recover, reconfiguration of the device is done after power cycling the device. The fluence that accumulated so far is used to calculate the cross section of SEFI for the particular LET.

Table 7-2 SEFI Runs

Flux (ions·cm²/s)	Ion	LET (MeV∙cm²/mg)	Time	Fluence (ions·cm²)	SEFI?	Cross Section (cm²)
1.00 × 10⁴	Ar	9.75	25 sec	2.45 × 10⁵	No	5.85 × 10^-6
1.00 × 10⁴			50 sec	4.88 × 10⁵	No
1.00 × 10⁴			75 sec	7.15 × 10⁵	No
1.00 × 10⁴			100 sec	9.53 × 10⁵	Yes
1.00 × 10²	Cu	24.54	5 min	4.43 × 10⁴	No	1.86 × 10^-5
1.00 × 10²			10 min	8.79 × 10⁴	No
1.00 × 10²			15 min	1.28 × 10⁵	No
1.00 × 10²			20 min	1.71 × 10⁵	No
1.00 × 10²			25 min	2.16 × 10⁵	No
1.00 × 10²			30 min	2.56 × 10⁵	No
1.00 × 10²			35 min	3.00 × 10⁵	Yes
1.00 × 10²	Ag	57.73	5 min	3.92 × 10⁴	No	2.33 × 10^-5
1.00 × 10²			20 min	1.60 × 10⁵	No
1.00 × 10²			25 min	2.00 × 10⁵	No
1.00 × 10²			30 min	2.39 × 10⁵	Yes