Evaluation of Single Event Effects Using the Ultrafast Pulsed Laser Facility at the Saskatchewan Structural Sciences Centre

Single event effects have been an issue in microelectronic devices and circuits for some time, especially those used in radiation-intense environments such as space. Traditionally, devices have been tested using particle accelerator facilities for evaluation of the various single event effects phenomena. However, testing at these facilities can be prohibitive to many research groups due to costs and time availability. As a result, pulsed laser testing has evolved to become a standard, additional testing methodology for evaluating single event effects. Not only do pulsed laser facilities generally offer more flexibility in terms of cost, but it is also possible to gain additional information about the spatial and temporal nature of single event effect generation in sensitive areas of a device. To meet the needs of the radiation effects community, pulsed laser facilities have continued to be set up around the world. One of these includes the facility at the Saskatchewan Structural Sciences Centre. An earlier iteration of the facility previously existed which utilized a different equipment set and did not have the two photon absorption capabilities that the current version does. In this thesis, a sample of the work performed at the facility using both the single and two photon absorption capabilities are provided to demonstrate its capabilities; the devices tested for single event effect response included two Hall effect sensors and a Xilinx Virtex-5 FPGA. Additionally, a description of the main features of the facility in its current form is given. Through this work, the feasibility of the facility to provide results to users, both academic and industrial, is demonstrated

Laser welding of shape memory alloys

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia MecânicaA necessidade de desenvolver técnicas avançadas de união para ligas com memória de forma tem-se revelado um assunto da maior importância, uma vez que as suas propriedades funcionais,nomeadamente o efeito de memória de forma e a superelasticidade, se revestem de enorme valor para aplicações actuais ou emergentes. De entre as ligas com memória de forma, o NiTi é a mais aplicada em campos tecnológicos tão diversos como a indústria biomédica, aerospacial e automóvel,o que se deve às suas características, como sejam: as elevadas biocompatibilidade e resistência à corrosão. Por estas razões, tem sido investigadas técnicas de ligação para estas ligas. No entanto, a sua ligação a outros materiais constitui um desafio cada vez maior permitindo explorar novos domínios de aplicação. O principal objectivo deste estudo é compreender o efeito da soldadura laser em aspectos estruturais, mecânicos e funcionais, tanto em ligações similares envolvendo NiTi, como dissimilares. Foram produzidas juntas similares topo a topo utilizando um laser de Nd:YAG em modo contínuo e estudados os efeitos da direcção de laminagem na configuração de junta e dos parâmetros do processo nas caraterísticas das juntas. A soldadura dissimilar de NiTi com Ti-6Al-4V foi realizada com um laser de fibras operando em modo contínuo. Adicionalmente, soldaram-se arames de NiTi com aço inoxidável austenítico utilizando uma fonte laser de Nd:YAG operando em modo pulsado. Foram projectados e produzidos sistemas de fixação e de protecção gasosa específicos para estas aplicações. Foram desenvolvidos e/ou adaptados métodos de ensaio para a avaliação da macro e microestructura, do comportamento mecânico cíclico e da capacidade de memória de forma. Utilizaram-se técnicas de análise como a Calorimetria Diferencial de Varrimento (DSC), a Microscopia Electrónica de Varrimento (SEM), EDS para identificação de espécies químicas e microdureza para avaliar as juntas soldadas. Foram produzidas juntas soldadas sem defeitos de soldadura utilizando parâmetros de processo optimizados, as quais apresentaram elevada tensão de rotura (acima de 400 MPa), patamares superelásticos até níveis de deformação próximos de 8%, comportamento cíclico superior ao material base e fractura dúctil. Foi observada baixa tensão de rotura nas juntas dissimilares sobrepostas com aço inoxidável AISI 316LN, devido à fractura prematura pela zona afectada pelo calor, no lado do NiTi. Nas juntas topo a topo de NiTi com Ti-6Al-4V a zona revela uma estrutura de solidificação rápida do tipo dendrítica na qual se propagaram fissuras com origem em defeitos de soldadura, tais como falta de penetração

Vulnerability of CMOS image sensors in megajoule class laser harsh environment

CMOS image sensors (CIS) are promising candidates as part of optical imagers for the plasma diagnostics devoted to the study of fusion by inertial confinement. However, the harsh radiative environment of Megajoule Class Lasers threatens the performances of these optical sensors. In this paper, the vulnerability of CIS to the transient and mixed pulsed radiation environment associated with such facilities is investigated during an experiment at the OMEGA facility at the Laboratory for Laser Energetics (LLE), Rochester, NY, USA. The transient and permanent effects of the 14 MeV neutron pulse on CIS are presented. The behavior of the tested CIS shows that active pixel sensors (APS) exhibit a better hardness to this harsh environment than a CCD. A first order extrapolation of the reported results to the higher level of radiation expected for Megajoule Class Laser facilities (Laser Megajoule in France or National Ignition Facility in the USA) shows that temporarily saturated pixels due to transient neutron-induced single event effects will be the major issue for the development of radiation-tolerant plasma diagnostic instruments whereas the permanent degradation of the CIS related to displacement damage or total ionizing dose effects could be reduced by applying well known mitigation techniques

Study of Radiation Effects on 28nm UTBB FDSOI Technology

With the evolution of modern Complementary Metal-Oxide-Semiconductor (CMOS) technology, transistor feature size has been scaled down to nanometers. The scaling has resulted in tremendous advantages to the integrated circuits (ICs), such as higher speed, smaller circuit size, and lower operating voltage. However, it also creates some reliability concerns. In particular, small device dimensions and low operating voltages have caused nanoscale ICs to become highly sensitive to operational disturbances, such as signal coupling, supply and substrate noise, and single event effects (SEEs) caused by ionizing particles, like cosmic neutrons and alpha particles. SEEs found in ICs can introduce transient pulses in circuit nodes or data upsets in storage cells. In well-designed ICs, SEEs appear to be the most troublesome in a space environment or at high altitudes in terrestrial environment. Techniques from the manufacturing process level up to the system design level have been developed to mitigate radiation effects. Among them, silicon-on-insulator (SOI) technologies have proven to be an effective approach to reduce single-event effects in ICs. So far, 28nm ultra-thin body and buried oxide (UTBB) Fully Depleted SOI (FDSOI) by STMicroelectronics is one of the most advanced SOI technologies in commercial applications. Its resilience to radiation effects has not been fully explored and it is of prevalent interest in the radiation effects community. Therefore, two test chips, namely ST1 and AR0, were designed and tested to study SEEs in logic circuits fabricated with this technology. The ST1 test chip was designed to evaluate SET pulse widths in logic gates. Three kinds of the on-chip pulse-width measurement detectors, namely the Vernier detector, the Pulse Capture detector and the Pulse Filter detector, were implemented in the ST1 chip. Moreover, a Circuit for Radiation Effects Self-Test (CREST) chain with combinational logic was designed to study both SET and SEU effects. The ST1 chip was tested using a heavy ion irradiation beam source in Radiation Effects Facility (RADEF), Finland. The experiment results showed that the cross-section of the 28nm UTBB-FDSOI technology is two orders lower than its bulk competitors. Laser tests were also applied to this chip to research the pulse distortion effects and the relationship between SET, SEU and the clock frequency. Total Ionizing Dose experiments were carried out at the University of Saskatchewan and European Space Agency with Co-60 gammacell radiation sources. The test results showed the devices implemented in the 28nm UTBB-FDSOI technology can maintain its functionality up to 1 Mrad(Si). In the AR0 chip, we designed five ARM Cortex-M0 cores with different logic protection levels to investigate the performance of approximate logic protecting methods. There are three custom-designed SRAM blocks in the test chip, which can also be used to measure the SEU rate. From the simulation result, we concluded that the approximate logic methodology can protect the digital logic efficiently. This research comprehensively evaluates the radiation effects in the 28nm UTBB-FDSOI technology, which provides the baseline for later radiation-hardened system designs in this technology

Recent Single Event Effects Compendium of Candidate Electronics for NASA Space Systems

We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results

Improved Fault Tolerant SRAM Cell Design & Layout in 130nm Technology

Technology scaling of CMOS devices has made the integrated circuits vulnerable to single event radiation effects. Scaling of CMOS Static RAM (SRAM) has led to denser packing architectures by reducing the size and spacing of diffusion nodes. However, this trend has led to the increase in charge collection and sharing effects between devices during an ion strike, making the circuit even more vulnerable to a specific single event effect called the single event multiple-node upset (SEMU). In nanometer technologies, SEMU can easily disrupt the data stored in the memory and can be more hazardous than a single event single-node upset. During the last decade, most of the research efforts were mainly focused on improving the single event single-node upset tolerance of SRAM cells by using novel circuit techniques, but recent studies relating to angular radiation sensitivity has revealed the importance of SEMU and Multi Bit Upset (MBU) tolerance for SRAM cells. The research focuses on improving SEMU tolerance of CMOS SRAM cells by using novel circuit and layout level techniques. A novel SRAM cell circuit & layout technique is proposed to improve the SEMU tolerance of 6T SRAM cells with decreasing feature size, making it an ideal candidate for future technologies. The layout is based on strategically positioning diffusion nodes in such a way as to provide charge cancellation among nodes during SEMU radiation strikes, instead of charge build-up. The new design & layout technique can improve the SEMU tolerance levels by up to 20 times without sacrificing on area overhead and hence is suitable for high density SRAM designs in commercial applications. Finally, laser testing of SRAM based configuration memory of a Xilinx Virtex-5 FPGA is performed to analyze the behavior of SRAM based systems towards radiation strikes

Study of Single-Event Transient Effects on Analog Circuits

Radiation in space is potentially hazardous to microelectronic circuits and systems such as spacecraft electronics. Transient effects on circuits and systems from high energetic particles can interrupt electronics operation or crash the systems. This phenomenon is particularly serious in complementary metal-oxide-semiconductor (CMOS) integrated circuits (ICs) since most of modern ICs are implemented with CMOS technologies. The problem is getting worse with the technology scaling down. Radiation-hardening-by-design (RHBD) is a popular method to build CMOS devices and systems meeting performance criteria in radiation environment. Single-event transient (SET) effects in digital circuits have been studied extensively in the radiation effect community. In recent years analog RHBD has been received increasing attention since analog circuits start showing the vulnerability to the SETs due to the dramatic process scaling. Analog RHBD is still in the research stage. This study is to further study the effects of SET on analog CMOS circuits and introduces cost-effective RHBD approaches to mitigate these effects. The analog circuits concerned in this study include operational amplifiers (op amps), comparators, voltage-controlled oscillators (VCOs), and phase-locked loops (PLLs). Op amp is used to study SET effects on signal amplitude while the comparator, the VCO, and the PLL are used to study SET effects on signal state during transition time. In this work, approaches based on multi-level from transistor, circuit, to system are presented to mitigate the SET effects on the aforementioned circuits. Specifically, RHBD approach based on the circuit level, such as the op amp, adapts the auto-zeroing cancellation technique. The RHBD comparator implemented with dual-well and triple-well is studied and compared at the transistor level. SET effects are mitigated in a LC-tank oscillator by inserting a decoupling resistor. The RHBD PLL is implemented on the system level using triple modular redundancy (TMR) approach. It demonstrates that RHBD at multi-level can be cost-effective to mitigate the SEEs in analog circuits. In addition, SETs detection approaches are provided in this dissertation so that various mitigation approaches can be implemented more effectively. Performances and effectiveness of the proposed RHBD are validated through SPICE simulations on the schematic and pulsed-laser experiments on the fabricated circuits. The proposed and tested RHBD techniques can be applied to other relevant analog circuits in the industry to achieve radiation-tolerance

NASA Goddard Space Flight Center's Compendium of Recent Single Event Effects Results

We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results

Research opportunities with compact accelerator-driven neutron sources

Since the discovery of the neutron in 1934 neutron beams have been used in a very broad range of applications, As an aging fleet of nuclear reactor sources is retired the use of compact accelerator–driven neutron sources (CANS) are becoming more prevalent. CANS are playing a significant and expanding role in research and development in science and engineering, as well as in education and training. In the realm of multidisciplinary applications, CANS offer opportunities over a wide range of technical utilization, from interrogation of civil structures to medical therapy to cultural heritage study. This paper aims to provide the first comprehensive overview of the history, current status of operation, and ongoing development of CANS worldwide. The basic physics and engineering regarding neutron production by accelerators, target-moderator systems, and beam line instrumentation are introduced, followed by an extensive discussion of various evolving applications currently exploited at CANS