Direct ionization from low energy protons is shown to cause upsets in a 65-nm bulk CMOS SRAM, consistent with results reported for other deep submicron technologies. The experimental data are used to ...calibrate a Monte Carlo rate prediction model, which is used to evaluate the importance of this upset mechanism in typical space environments. For the ISS orbit and a geosynchronous (worst day) orbit, direct ionization from protons is a major contributor to the total error rate, but for a geosynchronous (solar min) orbit, the proton flux is too low to cause a significant number of events. The implications of these results for hardness assurance are discussed.
Experimental results are presented on proton induced single-event-upsets (SEU) on a 65 nm silicon-on-insulator (SOI) SRAM. The low energy proton SEU results are very different for the 65 nm SRAM as ...compared with SRAMs fabricated in previous technology generations. Specifically, no upset threshold is observed as the proton energy is decreased down to 1 MeV; and a sharp rise in the upset cross-section is observed below 1 MeV. The increase below 1 MeV is attributed to upsets caused by direct ionization from the low energy protons. The implications of the low energy proton upsets are discussed for space applications of 65 nm SRAMs; and the implications for radiation assurance testing are also discussed.
A well-collapse source-injection mode for SRAM SEU is demonstrated through TCAD modeling. The recovery of the SRAM's state is shown to be based upon the resistive path from the p+ -sources in the ...SRAM to the well. Multiple cell upset patterns for direct charge collection and the well-collapse source-injection mechanisms are predicted and compared to SRAM test data.
The objectives, instrumentation, methods and data leading up to launch of the NASA Living With a Star (LWS) Space Environment Testbed (SET) payload onboard the Air Force Research Laboratory ...Demonstration and Science Experiments (DSX) spacecraft are described. The experiments characterize the space radiation environment and how it affects hardware performance. The payload consists of a compact space weather instrument and a carrier containing four board experiments.
Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A ...modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.
The proton-induced nonionizing energy loss (NIEL) for representative device materials are presented for the energy range between the displacement damage threshold to 1 GeV. All interaction mechanisms ...(Coulomb and nuclear elastic/nonelastic) are fully accounted for in the present NIEL calculations. For Coulomb interactions, the Ziegler-Biersack-Littmark (ZBL) screened potential was used in the lower energy range (<50 MeV) and the relativistic formulation was used in the higher energy range (/spl ges/50 MeV). A charged particle transport code, MCNPX, was used to compute the NIEL due to nuclear interactions.
A probabilistic model of cumulative solar heavy ion energy and LET spectra is developed for spacecraft design applications. Spectra are given as a function of confidence level, mission time period ...during solar maximum and shielding thickness. It is shown that long-term solar heavy ion fluxes exceed galactic cosmic ray fluxes during solar maximum for shielding levels of interest. Cumulative solar heavy ion fluences should therefore be accounted for in single event effects rate calculations and in the planning of space missions.
Near-Earth Space Radiation Models Xapsos, M. A.; O'Neill, P. M.; O'Brien, T. P.
IEEE transactions on nuclear science,
06/2013, Letnik:
60, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Review of models of the near-Earth space radiation environment is presented, including recent developments in trapped proton and electron, galactic cosmic ray and solar particle event models geared ...toward spacecraft electronics applications.
Experimental results are presented on single-bit-upsets (SBU) and multiple-bit-upsets (MBU) on a 45 nm SOI SRAM. The accelerated testing results show the SBU-per-bit cross section is relatively ...constant with technology scaling but the MBU cross section is increasing. The MBU data show the importance of acquiring and analyzing the data with respect to the location of the multiple-bit upsets since the relative location of the cells is important in determining which MBU upsets can be corrected with error correcting code (ECC) circuits. For the SOI SRAMs, a large MBU orientation effect is observed with most of the MBU events occurring along the same SRAM bit-line; allowing ECC circuits to correct most of these MBU events.
The method for predicting solar cell degradation in space radiation environments developed recently at the US Naval Research Laboratory (NRL) is compared in detail with the earlier method developed ...at the US Jet Propulsion Laboratory (JPL). Although both methods are similar, the key difference is that in the NRL approach, the energy dependence of the damage coefficients is determined from a calculation of the nonionizing energy loss (NIEL) and requires relatively few experimental measurements, whereas in the JPL method the damage coefficients have to be determined using an extensive set of experimental measurements. The end result of the NRL approach is a determination of a single characteristic degradation curve for a cell technology, which is measured against displacement damage dose rather than fluence. The end‐of‐life (EOL) cell performance for a particular mission can be read from the characteristic curve once the displacement damage dose for the mission has been determined. In the JPL method, the end result is a determination of the equivalent 1 MeV electron fluence, which would cause the same level of degradation as the actual space environment. The two approaches give similar results for GaAs/Ge solar cells, for which a large database exists. Because the NRL method requires far less experimental data than the JPL method, it is more readily applied to emerging cell technologies for which extensive radiation measurements are not available. The NRL approach is being incorporated into a code named SAVANT by researchers at NASA Glenn Research Center. The predictions of SAVANT are shown to agree closely with actual space data for GaAs/Ge and CuInSe2 cells flown on the Equator‐S mission. Published in 2001 by John Wiley & Sons, Ltd.
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