Neutron Single Event Effect Research Articles

Atmospheric Neutron Single Event Effects Research of Multiple Convolutional Neural Networks based on 28 nm and 16 nm SoC

Abstract The single event effects (SEEs) evaluations caused by atmospheric neutrons were conducted on three different convolutional neural network (CNN) models (Yolov3, MNIST, and ResNet50) in the atmospheric neutron irradiation spectrometer (ANIS) at the China Spallation Neutron Source (CSNS). The Yolov3 and MNIST models were implemented on the XILINX 28 nm system-on-chip (SoC). Meanwhile, the Yolov3 and ResNet50 models were deployed on the XILINX 16 nm FinFET UltraScale+ MPSoC. The atmospheric neutron SEEs on the tested CNN systems were comprehensively evaluated from six aspects, including chip type, network architecture, deployment methods, inference time, datasets, and the position of the anchor boxes. The various types of SEE soft errors, SEE cross-sections, and their distribution were analyzed to explore the radiation sensitivities and rules of 28 nm and 16 nm SoC. The current research can provide the technology support of radiation-resistant design of CNN system for developing and applying high-reliability, long-lifespan domestic artificial intelligence chips.

Neutron induced single event effects on near-memory computing architecture AI chips

For the near-memory computing architecture AI chip manufactured by using 16 nm FinFET technology, atmospheric neutron single event effect irradiation tests are conducted for the first time in China by using the atmospheric neutron irradiation spectrometer (ANIS) at the China Spallation Neutron Source. During the irradiation, the YOLOV5 algorithm neural network running on the AI chip is used for real-time detection of target objects, including mice, keyboard, and luggage. The purpose of the test is to investigate the new single event effect that may occur on near-memory computing architecture AI chip. Finally, at an accumulated neutron fluence of 1.51×10<sup>10</sup> n·cm<sup>–2</sup> (above 1 MeV), a total of 35 soft errors are detected in 5 categories. Particularly noteworthy is the observation of a new finding, where both computing and memory units experience single event effects simultaneously, which is different from the traditional von Neumann architecture chips. Based on the single event effects that occur simultaneously in these two units, combined with Monte Carlo simulation, a preliminary estimation is made of the physical layout distance between the computing unit and the memory unit on the chip. Furthermore, suggestions are proposed to simultaneously reduce the risk of single event effect in multi cells. This study provides valuable reference and insights for further exploring the single event effects in non-traditional von Neumann architecture chips.

Experimental study on neutron single event effects of commercial SRAMs based on CSNS

The experiment of neutron single event effect was carried out at China Spallation Neutron Source (CSNS) back-n on 13 kinds of commercial SRAM. The single event upset (SEU) cross section of each device was obtained, and multiple cell upsets (MCU) were extracted from the SEUs using a statistical method without layout information. The influences of the test pattern, feature size and device layout on the SEU cross section and MCU were studied. The results show that the test pattern has little influence on the SEU cross section of the devices, but has a great influence on the MCU ratio of some devices. The feature size has influence both on the SEU cross section and the MCU ratio of the devices. The influence on SEU cross section is not definite. The influence on the MCU ratio is definite. Both the ratio and the maximum size of the MCUs increase with the decrease of the feature size. The difference of layout has great influence both on the SEU cross section and the MCU ratio of the device. In addition, compared with the results of plateau irradiation, the ratio of MCU in CSNS back-n is less than that of plateau irradiation. There are two reasons for this difference. One is that the energy spectrum of CSNS back-n is softer than that of the atmospheric neutron. The other is the neutron beam at CSNS back-n is perpendicular to the device under test. Therefore, evaluating the atmospheric neutron SEE using CSNS back-n line may underestimate the MCU ratio of the device under test. The experimental data, analytical methods and results obtained in this paper are valuable for the researchers to carry out the atmospheric neutron SEE test and the evaluation of devices on atmospheric neutron SEE.

Impact of Device Structure on Neutron-Induced Single-Event Effect in SiC MOSFETs

Neutron single event effect (SEE) tolerance of SiC power MOSFETs with different drift region design were evaluated. The SEE is detected over the SEE threshold voltage (VSEE). The failure rate increases exponentially as the drain voltage increases above VSEE. The device with higher avalanche breakdown voltage has higher SEE threshold voltage. The neutron SEE tolerance of MOSFETs and PiN diodes of the same epitaxial structure were also evaluated. There was no significant difference in the neutron SEE tolerance of these devices.

Atmospheric neutron single event effect test on Xilinx 28 nm system on chip at CSNS-BL09

China Spallation Neutron Source (CSNS)–Beam Line 09 (BL09) was used to study 28 nm system on chip (SoC) atmospheric neutron single event effect for the first time. The on chip memory (OCM), D-Cache and BRAM blocks were tested respectively. Different single event effects were detected, such as single bit upset, multi cell upset and single event functional interruption. The experiment illustrated that there is a significant discrepancy in results whether neutron from 1 MeV to 10 MeV contributions are considered in studying 28 nm SoC single event effect. The experiment and Geant4 simulation results indicated that the influence of 1 MeV to 10 MeV neutron cannot be neglected. The average bit cross section and soft error rate (SER) per Mbit at Beijing sea level of the 28 nm SoC are 1.50 × 10−15 cm2·bit−1 and 22 FIT·Mbit−1.

Application and evaluation of Chinese spallation neutron source in single-event effects testing

Due to the lack of available spallation neutron source, the atmospheric neutron single event effect (SEE) in China were studied mainly by means of simulation and single energy neutron test. Since the Chinese spallation neutron source (CSNS) passed the national acceptance, it has become possible to carry out the research on atmospheric neutron SEE by using the CSNS. In this paper, the neutron SEE experiments of 3 kinds of SRAMs with different feature sizes are carried out for the first time by using the CSNS back-n. The application of CSNS back-n in the study of atmospheric neutron SEE is evaluated by comparing with the results of the earlier plateau experiment. The results show that the cross section of the single event upset is smaller than that of the plateau test, and the cross sections of different devices have no obvious monotonic relationship with feature size. The reason for the former result is that the energy spectrum of CSNS back-n is slightly softer than that of the atmospheric neutron. The reason for the second result is that small feature size means small critical charge and small sensitive volume, and these two factors compete with each other when they make the contribution to the cross section. According to the difference in energy spectrum and cross section among the SRAM devices, a correction factor is proposed to correct the test results based on CSNS back-n. For the difference in energy spectrum, different energy thresholds will produce different ratios between the cross sections by using CSNS back-n and atmospheric neutron. The neutrons of CSNS back-n are mainly concentrated around 1 MeV, which is close to the energy threshold of general SRAM devices. Thus, inaccurate energy threshold estimation will introduce a large error into the cross section of SEU. Thus, the relation between the correction factor and the energy threshold is analyzed. If 12 MeV is selected as the energy threshold to calculate the cross section, more consistent results could be obtained for our DUT in CSNS back-n and atmospheric neutron environment. In a word, the results show that the CSNS back-n can be used to speed up the atmospheric neutron SEE test, but the result should be corrected to evaluate the threat from atmospheric neutron. Fortunately, with the continuous increase of CSNS operating power, the neutron flux and the accelerated factor of CSNS will increase synchronously. Besides, other 3 white light neutron beams are planned in the CSNS project, the planned energy spectra are closer to those of atmospheric neutron. It is expected that the CSNS will be better applied to the study of atmospheric neutron SEE.

Atmospheric neutron single event effect in 65 nm microcontroller units by using CSNS-BL09

Atmospheric neutron single event effect in 65 nm microcontroller units by using CSNS-BL09

Characteristics of energy deposition from 1-1000 MeV proton and neutron induced nuclear reactions in silicon

The characteristics of the energy deposition of the secondary particles from the proton and neutron induced elastic and nonelastic reactions in silicon over a wide energy range of 1-1000 MeV, which are of great value for the proton and neutron single event effect (SEE) study, are investigated systematically in detail with Geant4 simulations. According to our simulation results, some important issues about the proton and neutron SEEs, including the energy dependence of the SEE cross sections, the equivalence of protons and neutrons in SEEs, the effects of the critical charge on SEEs, the geometric effect of the sensitive volumes, and the role of the elastic scattering mechanism in SEEs, are discussed. And some significant conclusions are tried to be drawn. With our systematic study, a comprehensive and profound understanding about the proton and neutron SEEs is reached from the physical perspective.

Neutron single event effects testing and evaluation method for avionics

The atmospheric neutron radiation reliability parameters,such as hard failure,hard error and soft error for avionics neutron single event effect( NSEE) were defined. A set of testing and evaluation method to demonstrate the avionics NSEE-resistance capability was presented and verified by a case study on some aircraft satellite navigation receiver NSEE testing and evaluation. The testing and evaluation method included test stress determination method on ending condition and starting condition,MNSEEprediction method,test procedures,testing and evaluation method,etc. This case study verifies that the NSEE testing and evaluation method for avionics is practical,operational and effective in the engineering application. The NSEE sensitivity features of DSP,SRAM and FPGA in aircraft satellite navigation receiver may provide pinpointed technical support for NSEE mitigation and protection for the related NSEE failure. The theoretical and application foundation is paved for atmospheric neutron single event effects testing and evaluation for avionics in China. In the meantime,it provides important and valuable reference for the atmospheric NSEE testing and evaluation for other electronic and information products in China.

Incorporation of Atmospheric Neutron Single Event Effects Analysis into a System Safety Assessment

Incorporation of Atmospheric Neutron Single Event Effects Analysis into a System Safety Assessment