No fault found (NFF) errors, i.e. errors which origin has not been established, irregularly occur in electronic devices. The actual cause of such errors varies but one, possibly more prominent, source for these soft errors is atmospheric radiation. The overarching aim of this thesis is to demonstrate: 1) the importance of keeping the atmospheric radiation environment in mind when designing robust airborne systems, 2) how to take this environment into consideration when applying mitigation techniques which may drastically reduce the risk of SEEs (Single Event Effects) which can cause NFF errors. To achieve these goals, Part 1 of this thesis describes how cosmic rays affect electronics (i.e. what kind of errors may be induced), which types of devices are susceptible to radiation, and why this subject is of extra importance for airborne systems. In addition, soft error mitigation techniques, which may be applied at different design levels to reduce the soft error rate (SER) or the impact of soft errors, are also presented. The aim is further corroborated by Part 2. Five subsystems of a modern aircraft are studied and real examples of failures potentially induced by atmospheric radiation are presented. For each of the five systems, all errors that have been reported for these (in the past few years) have been studied, and the number of errors found to be potentially induced by cosmic radiation has been listed and compared to number of expected soft errors based on calculations and previous experimental tests.

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Made available in DSpace on 2014-10-09T12:34:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:36Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:34:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:36Z (GMT). No. of bitstreams: 0 / Neste trabalho, cujo objetivo foi fornecer subsídios que permitam estabelecer um sistema de dosimetria para as tripulações de aeronaves que operam no território nacional, foi desenvolvida uma técnica para realizar medições do equivalente de dose ambiente em aeronaves. Foi testado um detector ativo, para uso embarcado em aeronaves, avaliando-se sua adequação a este tipo específico de medição, assim como sua suscetibilidade às interferências magnética e eletromagnética. O equipamento foi calibrado em campos metrologicamente rastreados e foi verificado em um campo especial do laboratório europeu CERN, que reproduz com grande proximidade o espectro de partículas existentes em altitudes de voo de aeronaves, sendo a seguir testado em diversos ensaios em voo, em uma aeronave da Força Aérea Brasileira. Os resultados foram avaliados e comparados com aqueles obtidos por diversos programas computacionais de estimativa de dose oriunda de radiação cósmica, com respeito à sua adequação para uso na região da América do Sul e foi selecionado o programa CARI-6 para avaliar as doses efetivas médias estimadas a que estão sujeitas as tripulações que operam nesta região. Foi efetuada uma avaliação estatística da distribuição de doses efetivas das tripulações dos voos que operam na região da América do Sul e Caribe e concluiu-se que grande parte destas tripulações estão sujeitas a doses efetivas anuais que ultrapassam o limite estabelecido para membros do público. Adicionalmente, foi proposto um dosímetro passivo preliminar, baseado em detectores termoluminescentes, e foram ainda estabelecidas colaborações internacionais com grupos de pesquisa do Reino Unido e da Itália, para a realização de medições conjuntas do equivalente de dose ambiente em aeronaves. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Neste trabalho, cujo objetivo foi fornecer subsídios que permitam estabelecer um sistema de dosimetria para as tripulações de aeronaves que operam no território nacional, foi desenvolvida uma técnica para realizar medições do equivalente de dose ambiente em aeronaves. Foi testado um detector ativo, para uso embarcado em aeronaves, avaliando-se sua adequação a este tipo específico de medição, assim como sua suscetibilidade às interferências magnética e eletromagnética. O equipamento foi calibrado em campos metrologicamente rastreados e foi verificado em um campo especial do laboratório europeu CERN, que reproduz com grande proximidade o espectro de partículas existentes em altitudes de voo de aeronaves, sendo a seguir testado em diversos ensaios em voo, em uma aeronave da Força Aérea Brasileira. Os resultados foram avaliados e comparados com aqueles obtidos por diversos programas computacionais de estimativa de dose oriunda de radiação cósmica, com respeito à sua adequação para uso na região da América do Sul e foi selecionado o programa CARI-6 para avaliar as doses efetivas médias estimadas a que estão sujeitas as tripulações que operam nesta região. Foi efetuada uma avaliação estatística da distribuição de doses efetivas das tripulações dos voos que operam na região da América do Sul e Caribe e concluiu-se que grande parte destas tripulações estão sujeitas a doses efetivas anuais que ultrapassam o limite estabelecido para membros do público. Adicionalmente, foi proposto um dosímetro passivo preliminar, baseado em detectores termoluminescentes, e foram ainda estabelecidas colaborações internacionais com grupos de pesquisa do Reino Unido e da Itália, para a realização de medições conjuntas do equivalente de dose ambiente em aeronaves. / The objective of this work is the establishment of a dosimetric system for the aircrew in the domestic territory. A technique to perform measurements of ambient dose equivalent in aircrafts was developed. An active detector was evaluated for onboard aircraft use, testing its adequacy to this specific type of measurement as well as its susceptibility to the magnetic and electromagnetic interferences. The equipment was calibrated in standard radiation beams and in a special field of the European Laboratory CERN, that reproduces with great proximity the real spectrum in aircraft flight altitudes; it was also tested in several flights, in an Brazilian Air Force\'s aircraft. The results were evaluated and compared with those obtained from several computational programs for cosmic radiation estimatives, with respect to its adequacy for use in the South American region. The program CARI-6 was selected to evaluate the estimated averaged effective doses for the aircrew who operate in this region. A statistical distribution of aircrew effective doses in South America and Caribe was made, and the results show that a great part of this aircrew members are subjected to annual effective doses that exceed the dose limits for the members of the public. Additionally, a preliminary passive dosemeter, based in thermoluminescent detectors, was proposed; international collaborations with United Kingdom and Italy were established for joint measurements of the ambient equivalent doses in aircrafts.

Sammanfattning: SAAB Communication i Linköping sysslar med konsultverksamhet mot ett flertal nationella och internationella företag inom både den civila och militära sektorn. Fokus ligger på flyget med uppdrag inom telesystem, radiosystem, signaturanpassning, EMC, atmosfärisk påverkan mm. I det sistnämnda ingår även kosmisk strålnings inverkan på elektronik. Den fortsatta miniatyriseringen av elektronik, speciellt minneselektronik leder till ökad känslighet mot den kosmiska partikelstrålningen som ständigt regnar ner på jorden, därför är det extra noga att minnen testas innan de sätts i bruk vid flygburna system. Syftet med detta examensarbete är att konstruera en provplattform som registrerar fel som uppkommer i ett DDR2 SDRAM minne vid påverkan av den ovannämnda strålningen. Detta examensarbete är en vidareutveckling av en provplattform baserad på en FPGA – lösning. Eftersom denna provplattform saknade stöd för den snabbare minnestypen DDR2 SDRAM, blev syftet med detta examensarbete att ta fram en ny plattform som stödjer denna typ av minne. Den nya provplattformen är en PowerPC baserad lösning från Freescale Semiconductor®. Provplattformen kommer att anslutas till en PC som kör ett program som analyserar antalet detekterade minnesfel, typ av fel samt hur många neutroner minnet har blivit utsatt för under testet. Mjukvaruutvecklingen implementeras i programmeringsspråken assembler samt C. Innan testet av minnet påbörjas, fylls minnet med ett förbestämt bitmönster, om förändringar av bitmönstret sker vid bestrålning av minnet kommer dessa ändringar att registreras tillsammans med den minnesadress där felet inträffade. Abstract: SAAB Communication in Linköping offers consulting toward several national and international companies, both within the civilian and the military market. Focus is in the field of avionics and deals with telecommunication system, radio system, signature adaption, EMC, atmospheric impact etc. The later also includes the influence of cosmic radiation in electronics. The oncoming miniaturisation of electronics, especially within the memory fields causes an increased susceptibility of cosmic radiation that constantly hits our planet, therefore it is of great importance that memories is to be tested before used in airborne systems. The purpose of this thesis is to construct a test platform in order to register faults that occur in a DDR2 SDRAM memory under influence of the mentioned radiation. This thesis is further development of a test platform previously based on a FPGA – solution. Since this test platform had not to support for the more rapidly type of memory as DDR2 SDRAM, the purpose of this thesis became to develop a new platform with support for this type of memory. This new test platform is based on PowerPC from Freescale Semiconductor® The test platform will be connected to a PC running a program that counts the number of detected memory faults, recognises a type of error and records the number of neutrons that the memory has been exposed to during the test. The software is implemented in the programming languages assembler and C. The tested memory will be loaded with a predetermined bit pattern before the test begins, if a change in the bit pattern is detected during exposure of radiation, these faulty bit patterns will be registered together with the memory address where the error has occurred. / Andreas Skoglund Gustav adolfsg. 4 58220 Linköping 0739-230620 ti00ask@student.bth.se, andreas.skoglund@gmail.com, andreas.skoglund@saabgroup.com

No description available.

<p>Nuclear particles hitting the silicon in a electronic device can cause a change in the data in a memory bit cell or in a flip-flop. The device is still working, but the data is corrupted and this is called a soft error. A soft error caused by a single nuclear particle is called a single event upset and is a growing problem. Research is ongoing at Saab aiming at how susceptible random access memories are to protons and neutrons.</p><p>This thesis describes the development of equipment for measuring cosmic-ray effects on DRAM in laboratories. The system is built on existing hardware with a FPGA as the core unit. A short history of soft errors is also given and what causes it. How a DRAM works and basic operation is explained and the difference between a SRAM. The result is a working system ready to be used.</p>

Characterizing high z high energy (HZE) particles in cosmic radiation is of importance for the study of the equivalent dose to astronauts. Low pressure, tissue equivalent proportional counters (TEPC) are routinely used to evaluate radiation exposures in space. A multiple detector system composed of three TEPC of different sizes was simulated using the Monte-Carlo software toolkit GEANT4. The ability of the set of detectors to characterize HZE particles, as well as measure dose, was studied. HZE particles produce energetic secondary electrons (-rays) which carry a significant fraction of energy lost by the primary ion away from its track. The range and frequency of these delta rays depends on the velocity and charge of the primary ion. Measurements of lineal energy spectra in different size sites will differ because of these delta ray events and may provide information to characterize the incident primary particle. Monte Carlo calculations were accomplished, using GEANT4, simulating solid walled proportional detectors with unit density site diameter of 0.1, 0.5 and 2.5 µm in a uniform HZE particle field. The simulated spherical detectors have 2 mm thick tissue equivalent walls. The uniform beams of 1 GeV/n, 500 MeV/n and 100 MeV/n 56Fe, 28Si, 16O, 4He and proton particles were used to bombard the detector. The size effect of such a detector system was analyzed with the calculation results. The results show that the y vs. yf(y) spectrum differs significantly as a function of site size. From the spectra, as well as the calculated mean lineal energy, the simulated particles can be characterized. We predict that the detector system is capable of characterizing HZE particles in a complex field. This suggests that it may be practical to use such a system to measure the average particle velocity as well as the absorbed dose delivered by HZE particles in space. The parameters used in the simulation are also good references for detector construction. characterizing HZE particles in a complex field. This suggests that it may be practical to use such a system to measure the average particle velocity as well as the absorbed dose delivered by HZE particles in space. The parameters used in the simulation are also good references for detector construction.

Paper presented before the Second Pan American Scientific Congress, Washington, U.S.A., December 27, 1915-Janunary 8, 1916.