Shortcomings in ground testing, environment simulations, and performance predictions for space applications

This paper addresses the issues involved in radiation testing of devices and subsystems to obtain the data that are required to predict the performance and survivability of satellite systems for extended missions in space. The problems associated with space environmental simulations, or the lack thereof, in experiments intended to produce information to describe the degradation and behavior of parts and systems are discussed. Several types of radiation effects in semiconductor components are presented, as for example: ionization dose effects, heavy ion and proton induced Single Event Upsets (SEUs), and Single Event Transient Upsets (SETUs). Examples and illustrations of data relating to these ground testing issues are provided. The primary objective of this presentation is to alert the reader to the shortcomings, pitfalls, variabilities, and uncertainties in acquiring information to logically design electronic subsystems for use in satellites or space stations with long mission lifetimes, and to point out the weaknesses and deficiencies in the methods and procedures by which that information is obtained

On the feasibility of radiation sterilization of planetary spacecraft Final report

Feasibility study for X-ray or gamma ray sterilization of spacecraft - radiation effect

Характеристики pin-структуры с дискретно металлизированной поверхностью i-области

Introduction. Currently, an interest in improving pin-structures continues to be the focus of attention of developers of electronic devices. Devices that use controlled pin-structures include: non-volatile memory, static voltage protection device, pin-diodes with adjustable characteristics, etc. However, insufficient attention is paid to the issue of controlling the characteristics of pin-structures by using discrete metallization on the surface of i-region.Aim. Investigation of the influence of discrete metallization of the surface of i-region on static and dynamic characteristics of pin-structure, defect compensation, and efficiency control of the pin-photodetector.Materials and methods. The pin-structure under study consisted of p + -boron-doped region; n + -phosphorusdoped region; i-phosphorus-doped region; semi-insulating substrate; metallization of the substrate; polysilicon control gate; and a silicon oxide dielectric layer. Two-dimensional numerical analysis of the potential distribution, of the concentration of free charge carriers and currents was performed in the Synopsys Sentaurus TCAD environment.Results. Two-dimensional analysis of discretely metallized pin-structures was performed. The stresses applied to the gates of i-region that compensated the influence of defects formed by electron irradiation were determined. Four pin-photodetector structures were modeled, in which the control gates were performed in the form of metal–dielectric–semiconductor structure. The possibility of increasing the sensitivity of the pinphotodetector by applying the corresponding potentials to the gates was demonstrated.Conclusion. An effect of discrete metallization of i-region of the pin-structure was investigated. A method for correcting of the characteristics of the irradiated pin-diode to the initial characteristics was proposed. It makes possible to use such diodes in electronics with high requirements for operating in areas with high radiation. The design of a high-sensitivity photodetector with control gates on the surface of i-region and with the structure of low alloy i-region split into two regions (p- and n–type conductivity) was proposed.Введение. В настоящее время интерес к совершенствованию pin-структур продолжает оставаться в центре внимания разработчиков электронных устройств. К устройствам, в которых используются такие структуры, можно отнести энергонезависимую память, устройство защиты от статического напряжения, pin-диоды с регулируемыми характеристиками и др. Однако вопросу управления характеристиками pin-структур посредством использования дискретной металлизации на поверхности i-области уделено недостаточное внимание.Цель работы. Исследование влияния дискретной металлизации поверхности i-области на статические и динамические характеристики pin-структуры, компенсацию дефектов, управление эффективностью pinфотодетектора.Материалы и методы. Исследуемая pin-структура состоит из p+-области, легированной бором; n+- области, легированной фосфором; i-области, легированной фосфором; полуизолирующей подложки; металлизации подложки; управляющего затвора из поликремния; слоя диэлектрика из оксида кремния. Двумерный численный анализ распределения потенциала, концентрации свободных носителей заряда и токов выполнялся в среде Synopsys Sentaurus TCAD.Результаты. Выполнен двумерный анализ дискретно металлизированных pin-структур. Определены напряжения, подаваемые на затворы i-области, компенсирующие влияние дефектов, образованных электронным облучением. Проведено моделирование четырех структур pin-фотодетектора, в которых управляющие затворы выполнены в виде структуры металл–диэлектрик–полупроводник. Показана возможность увеличения чувствительности pin-фотодетектора подачей соответствующих потенциалов на затворы.Заключение. Исследовано влияние дискретной металлизации i-области pin-структуры. Предложен метод коррекции характеристик облученного pin-диода до исходных характеристик. Тем самым появляется возможность использовать такие диоды в электронике с высокими требованиями к работе в зонах с повышенной радиацией. Предложена конструкция фотодетектора повышенной чувствительности с управляющими затворами на поверхности i-области и с разделением структуры низколегированной i-области на две области р- и n-типов проводимости

Protection Against Radiation Hazards in Space, Book I Proceedings of the Symposium at Gatlinburg, Tenn., Nov. 5-7, 1962

Protection against radiation hazards in spac

Voyager electronic parts radiation program, volume 1

The Voyager spacecraft is subject to radiation from external natural space, from radioisotope thermoelectric generators and heater units, and from the internal environment where penetrating electrons generate surface ionization effects in semiconductor devices. Methods for radiation hardening and tests for radiation sensitivity are described. Results of characterization testing and sample screening of over 200 semiconductor devices in a radiation environment are summarized

Investigation of radiation-hardened design of electronic systems with applications to post-accident monitoring for nuclear power plants

This research aims at improving the robustness of electronic systems used-in high level radiation environments by combining with radiation-hardened (rad-hardened) design and fault-tolerant techniques based on commercial off-the-shelf (COTS) components. A specific of the research is to use such systems for wireless post-accident monitoring in nuclear power plants (NPPs). More specifically, the following methods and systems are developed and investigated to accomplish expected research objectives: analysis of radiation responses, design of a radiation-tolerant system, implementation of a wireless post-accident monitoring system for NPPs, performance evaluation without repeat physical tests, and experimental validation in a radiation environment. A method is developed to analyze ionizing radiation responses of COTS-based devices and circuits in various radiation conditions, which can be applied to design circuits robust to ionizing radiation effects without repeated destructive tests in a physical radiation environment. Some mathematical models of semiconductor devices for post-irradiation conditions are investigated, and their radiation responses are analyzed using Technology Computer Aided Design (TCAD) simulator. Those models are then used in the analysis of circuits and systems under radiation condition. Based on the simulation results, method of rapid power off may be effectively to protect electronic systems under ionizing radiation. It can be a potential solution to mitigate damages of electronic components caused by radiation. With simulation studies of photocurrent responses of semiconductor devices, two methods are presented to mitigate the damages of total ionizing dose: component selection and radiation shielding protection. According to the investigation of radiation-tolerance of regular COTS components, most COTS-based semiconductor components may experience performance degradation and radiation damages when the total dose is greater than 20 K Rad (Si). A principle of component selection is given to obtain the suitable components, as well as a method is proposed to assess the component reliability under radiation environments, which uses radiation degradation factors, instead of the usual failure rate data in the reliability model. Radiation degradation factor is as the input to describe the radiation response of a component under a total radiation dose. In addition, a number of typical semiconductor components are also selected as the candidate components for the application of wireless monitoring in nuclear power plants. On the other hand, a multi-layer shielding protection is used to reduce the total dose to be less than 20 K Rad (Si) for a given radiation condition; the selected semiconductor devices can then survive in the radiation condition with the reduced total dose. The calculation method of required shielding thickness is also proposed to achieve the design objectives. Several shielding solutions are also developed and compared for applications in wireless monitoring system in nuclear power plants. A radiation-tolerant architecture is proposed to allow COTS-based electronic systems to be used in high-level radiation environments without using rad-hardened components. Regular COTS components are used with some fault-tolerant techniques to mitigate damages of the system through redundancy, online fault detection, real-time preventive remedial actions, and rapid power off. The functions of measurement, processing, communication, and fault-tolerance are integrated locally within all channels without additional detection units. A hardware emulation bench with redundant channels is constructed to verify the effectiveness of the developed radiation-tolerant architecture. Experimental results have shown that the developed architecture works effectively and redundant channels can switch smoothly in 500 milliseconds or less when a single fault or multiple faults occur. An online mechanism is also investigated to timely detect and diagnose radiation damages in the developed redundant architecture for its radiation tolerance enhancement. This is implemented by the built-in-test technique. A number of tests by using fault injection techniques have been carried out in the developed hardware emulation bench to validate the proposed detection mechanism. The test results have shown that faults and errors can be effectively detected and diagnosed. For the developed redundant wireless devices under given radiation dose (20 K Rad (Si)), the fault detection coverage is about 62.11%. This level of protection could be improved further by putting more resources (CPU consumption, etc.) into the function of fault detection, but the cost will increase. To apply the above investigated techniques and systems, under a severe accident condition in a nuclear power plant, a prototype of wireless post-accident monitoring system (WPAMS) is designed and constructed. Specifically, the radiation-tolerant wireless device is implemented with redundant and diversified channels. The developed system operates effectively to measure up-to-date information from a specific area/process and to transmit that information to remote monitoring station wirelessly. Hence, the correctness of the proposed architecture and approaches in this research has been successfully validated. In the design phase, an assessment method without performing repeated destructive physical tests is investigated to evaluate the radiation-tolerance of electronic systems by combining the evaluation of radiation protection and the analysis of the system reliability under the given radiation conditions. The results of the assessment studies have shown that, under given radiation conditions, the reliability of the developed radiation-tolerant wireless system can be much higher than those of non-redundant channels; and it can work in high-level radiation environments with total dose up to 1 M Rad (Si). Finally, a number of total dose tests are performed to investigate radiation effects induced by gamma radiation on distinct modern wireless monitoring devices. An experimental setup is developed to monitor the performance of signal measurement online and transmission of the developed distinct wireless electronic devices directly under gamma radiator at The Ohio State University Nuclear Reactor Lab (OSU-NRL). The gamma irradiator generates dose rates of 20 K Rad/h and 200 Rad/h on the samples, respectively. It was found that both measurement and transmission functions of distinct wireless measurement and transmission devices work well under gamma radiation conditions before the devices permanently damage. The experimental results have also shown that the developed radiation-tolerant design can be applied to effectively extend the lifespan of COTS-based electronic systems in the high-level radiation environment, as well as to improve the performance of wireless communication systems. According to testing results, the developed radiation-tolerant wireless device with a shielding protection can work at least 21 hours under the highest dose rate (20 K Rad/h). In summary, this research has addressed important issues on the design of radiation-tolerant systems without using rad-hardened electronic components. The proposed methods and systems provide an effective and economical solution to implement monitoring systems for obtaining up-to-date information in high-level radiation environments. The reported contributions are of significance both academically and in practice

Space Photovoltaic Research and Technology 1986. High Efficiency, Space Environment, and Array Technology

The conference provided a forum to assess the progress made, the problems remaining, and the strategy for the future of photovoltaic research. Cell research and technology, space environmental effects, array technology and applications were discussed

Radiation Effects in Materials

The study of radiation effects has developed as a major field of materials science from the beginning, approximately 70 years ago. Its rapid development has been driven by two strong influences. The properties of the crystal defects and the materials containing them may then be studied. The types of radiation that can alter structural materials consist of neutrons, ions, electrons, gamma rays or other electromagnetic waves with different wavelengths. All of these forms of radiation have the capability to displace atoms/molecules from their lattice sites, which is the fundamental process that drives the changes in all materials. The effect of irradiation on materials is fixed in the initial event in which an energetic projectile strikes a target. The book is distributed in four sections: Ionic Materials; Biomaterials; Polymeric Materials and Metallic Materials

Laboratory Directed Research and Development Program FY 2007 Annual Report

The Oak Ridge National Laboratory (ORNL) Laboratory Directed Research and Development (LDRD) program reports its status to the U.S. Department of Energy (DOE) in March of each year. The program operates under the authority of DOE Order 413.2B, 'Laboratory Directed Research and Development' (April 19, 2006), which establishes DOE's requirements for the program while providing the Laboratory Director broad flexibility for program implementation. LDRD funds are obtained through a charge to all Laboratory programs. This report includes summaries for all ORNL LDRD research activities supported during FY 2007. The associated FY 2007 ORNL LDRD Self-Assessment (ORNL/PPA-2008/2) provides financial data and an internal evaluation of the program's management process. ORNL is a DOE multiprogram science, technology, and energy laboratory with distinctive capabilities in materials science and engineering, neutron science and technology, energy production and end-use technologies, biological and environmental science, and scientific computing. With these capabilities ORNL conducts basic and applied research and development (R&D) to support DOE's overarching mission to advance the national, economic, and energy security of the United States and promote scientific and technological innovation in support of that mission. As a national resource, the Laboratory also applies its capabilities and skills to specific needs of other federal agencies and customers through the DOE Work for Others (WFO) program. Information about the Laboratory and its programs is available on the Internet at http://www.ornl.gov/. LDRD is a relatively small but vital DOE program that allows ORNL, as well as other DOE laboratories, to select a limited number of R&D projects for the purpose of: (1) maintaining the scientific and technical vitality of the Laboratory; (2) enhancing the Laboratory's ability to address future DOE missions; (3) fostering creativity and stimulating exploration of forefront science and technology; (4) serving as a proving ground for new research; and (5) supporting high-risk, potentially high-value R&D. Through LDRD the Laboratory is able to improve its distinctive capabilities and enhance its ability to conduct cutting-edge R&D for its DOE and WFO sponsors. To meet the LDRD objectives and fulfill the particular needs of the Laboratory, ORNL has established a program with two components: the Director's R&D Fund and the Seed Money Fund. As outlined in Table 1, these two funds are complementary. The Director's R&D Fund develops new capabilities in support of the Laboratory initiatives, while the Seed Money Fund is open to all innovative ideas that have the potential for enhancing the Laboratory's core scientific and technical competencies. Provision for multiple routes of access to ORNL LDRD funds maximizes the likelihood that novel ideas with scientific and technological merit will be recognized and supported