High Energy and Thermal Neutrons Sensitivity of Google Tensor Processing Units

In this article, we investigate the reliability of Google’s coral tensor processing units (TPUs) to both high-energy atmospheric neutrons (at ChipIR) and thermal neutrons from a pulsed source [at equipment materials and mechanics analyzer (EMMA)] and from a reactor [at Thermal and Epithermal Neutron Irradiation Station (TENIS)]. We report data obtained with an overall fluence of 3.41×1012n/cm2 for atmospheric neutrons (equivalent to more than 30 million years of natural irradiation) and of 7.55×1012n/cm2 for thermal neutrons. We evaluate the behavior of TPUs executing elementary operations with increasing input sizes (standard convolutions or depthwise convolutions) as well as eight convolutional neural networks (CNNs) configurations (single-shot multibox detection (SSD) MobileNet v2 and SSD MobileDet, trained with COCO dataset, and Inception v4 and ResNet-50, with ILSVRC2012 dataset). We found that, despite the high error rate, most neutron-induced errors only slightly modify the convolution output and do not change the detection or classification of CNNs. By reporting details about the error model, we provide valuable information on how to design the CNNs to avoid neutron-induced events to lead to misdetections or classifications

SEE sensitivity of a COTS 28-nm SRAM-based FPGA under thermal neutrons and different incident angles

This paper provides an experimental study of the single-event upset (SEU) susceptibility against thermal neutron radiation of a 28-nm bulk Commercial-Off-The-Shelf (COTS) Xilinx Artix-7 FPGA under different angles of incidence. Experimental results indicating SEUs on configuration RAM (CRAM) cells, Flip-Flops (FFs), and Block RAMs (BRAMs) are presented and discussed. Shapes of multiple events (ranging from 2 to 12-bit) are also analyzed, and their dependency on the incident angle of the particle beam against the device’s surface. Possible shapes of 128 and 384-bit multiple events are also investigated, revealing a trend to follow word lines. The results of the front incident angle are compared with 14.2-MeV neutrons, demonstrating a considerable difference in the device’s sensitivity against both irradiation sources. Finally, a modeling tool called MUSCA-SEP3 is used to predict the device’s sensitivity under the same environmental conditions. The obtained experimental results will show a good agreement with the predicted ones in a very accurate way

All-solid-state lithium-ion batteries based on self-supported titania nanotubes

International audienceWe report the fabrication of an all-solid-state lithium-ion battery composed of self-supported titania nanotubes (TiO(2)nts) as anode, a thin film of polyethylene oxide (PEO) carrying bis(trifluoromethanesulfone)imide (LiTFSI) as electrolyte and a layer of LiNi0.5Mn1.5O4 as cathode. The battery shows an operating voltage of 2.1 V and delivers a stable discharge capacity of 80 mA h g(-1) (30 mu A h cm(-2) mu m(-1)) at a kinetic rate of C/10 with a capacity retention of 91.5% and a coulombic efficiency of 96.7%. This full cell showing high performance is compatible with the integrated circuit technology. (C) 2014 Elsevier B.V. All rights reserved

Effects of Thermal Neutron Irradiation on a Self-Refresh DRAM

In this study, static and dynamic test methods were used to define the response of a self-refresh DRAM under thermal neutron irradiation. The neutron-induced failures were investigated and characterized by event cross-sections, soft-error rate and bitmaps evaluations, leading to an identification of permanent and temporarily stuck cells, block errors, and singlebit upsets

Thermal-to-high-energy neutron SEU characterization of commercial SRAMs

Several commercial SRAMs have been tested by the CERN R2E project with neutrons of various energy. The test data are used to cross-compare facilities and to analyze variabilities within SRAMs from the same manufacturer. FIT for atmospheric and ground applications are provided as well as predictions for accelerator soft error rates

Microstructure et propriétés piézoélectriques/ferroélectriques à l’échelle locale d’un nouveau composé α-Nd₂WO₆ sous forme de film mince.

National audienc

Neutron-induced effects on a self-refresh DRAM

The field of radiation effects in electronics research includes unknowns for every new device, node size, and technical development. In this study, static and dynamic test methods were used to define the response of a self-refresh DRAM under neutron irradiation. The neutron-induced effects were investigated and characterised by event cross sections, soft-error rate, and bitmaps evaluations, leading to an identification of permanent and temporary stuck cells, single-bit upsets, and block errors. Block errors were identified in different patterns with dependency in the addressing order, leading to up to two thousand faulty words per event, representing a real threat from a user perspective, especially in critical applications. An analysis of the damaged cells' retention time was performed, showing a difference in the efficiency of the self-refresh mechanism and a read operation. Also, a correlation of the fault mechanism that generates both single-bit upsets and stuck bits is proposed. Post-irradiation high-temperature annealing procedures were applied, showing a recovery behaviour on the damaged cells.peerReviewe

An Analysis of the Significance of the 14N(n, p) 14C Reaction for Single-Event Upsets Induced by Thermal Neutrons in SRAMs

The thermal neutron threat to the reliability of electronic devices caused by $^{10}\text{B}$ capture is a recognized issue that prompted changes in the manufacturing process of electronic devices with the aim of limiting as much as possible the presence of this isotope nearby device sensitive volumes (SVs). $^{14}\text{N}$ can also capture thermal neutrons and release low-energy protons (LEPs; through the $^{14}\text{N}$ (n, p) $^{14}\text{C}$ reaction) that have high enough linear energy transfer (LET) to cause single-event upsets (SEUs). Typically, nitrogen is used in thin barrier layers made of TaN or TiN or even as insulator in the form of Si3N4. Numerical simulations on SVs calibrated on proton and ion experimental data and with an accurate description of the metallization layer on top of the sensitive region show that the presence of nitrogen in these thin barrier layers can be enough to justify the experimentally observed thermal neutron SEU cross Section for a static random access memory (SRAM) sensitive to LEPs. Nevertheless, the expected SEU cross Section from thermal neutrons is usually a few orders of magnitude lower than that of high-energy particles, therefore, not representing an important threat in atmospheric applications. At the same time, for high-energy accelerators, the contribution to the total soft error rate (SER) could become substantial, though easy to handle by margins