Showing papers by "Petteri Nieminen published in 2011"

Modeling Radiation Chemistry in the Geant4 Toolkit

Abstract: Mathieu KARAMITROS , Alfonso MANTERO , Sebastien INCERTI , Werner FRIEDLAND , Gerard BALDACCHINO , Philippe BARBERET , Mario BERNAL , Riccardo CAPRA , Christophe CHAMPION , Ziad EL BITAR , Ziad FRANCIS , Paul GUEYE , Anton IVANCHENKO , Vladimir IVANCHENKO , Hisaya KURASHIGE , Barbara MASCIALINO , Philippe MORETTO , Petteri NIEMINEN , Giovanni SANTIN , Herve SEZNEC , Hoang N. TRAN , Carmen VILLAGRASA 9 and Christina ZACHARATOU 15

Unfolding and validation of SREM fluxes

Abstract: The Standard Radiation Environment Monitor (SREM) belongs to a second generation of instruments in a program established by the European Research and Technology Centre of the European Space Agency (ESA) to provide minimum intrusive particle radiation detectors on ESA spacecraft for space weather applications, which are also suitable for scientific investigations.

Investigations of single event effects with heavy ions of energies up to 1.5 GeV/n

Abstract: The ESA SEU-Monitor, a 2 Gbit DDR2 SDRAM and a 100 V n-channel power MOSFET have been irradiated at GSI with ions of energies from 80 to 1500 MeV/n. The measured SEE sensitivities are compared to low energy $( data. The ESA SEU-Monitor and the DDR2 SDRAM showed only differences in the cross sections below the ionization threshold. Here the cross sections were lower for the high energy ions compared to the low energy ions. The power MOSFETs on the other hand showed a reduced safe operating area (SOA) for the high energy ions, although some experimental reasons other than the ion energy cannot be ruled out here.

Solar particle event analysis using the standard radiation environment monitors: applying the neutron monitor's experience

Abstract: The Standard Radiation Environment Monitor (SREM) is a particle detector developed by the European Space Agency for satellite applications with the main pur- pose to provide radiation hazard alarms to the host space- craft. SREM units have been constructed within a radiation hardening concept and therefore are able to register extreme solar particle events (SPEs). Large SPEs are registered at Earth, by ground based detectors as neutron monitors, in the form of Ground Level Enhancements of solar cosmic rays. In this work, a feasibility study of a possible radiation alert, deduced by SREM measurements was implemented for the event of 20 January 2005. Taking advantage of the neutron monitor's experience, the steps of the GLE alert algorithm were put into practice on SREM measurements. The out- come was that SREM units did register the outgoing SPE on-time and that these could serve as indicators of radiation hazards, leading to successful alerts.

Calibration of the weighed sensitive volume model to heavy ion experimental data

Abstract: The shape of the single event effect (SEE) cross section as a function of the ion's linear energy transfer (LET) can be explained in terms of intra-cell variations of the charge collection efficiency within the cell as opposed the inter-cell spread in the critical charge, as assumed earlier. Free charge carriers generated in areas in absence of electric field but near the depletion region may reach the latter through diffusion processes, then being collected by drift forces in the p-n junction of the semiconductor. In this context, a model of the SV in which different regions are defined through charge collection efficiencies (CCE) is pertinent. A method for calibrating this model to experimental data is proposed, as well as a practical example of how this can be done. A crucial aspect of this technique is that, as will be shown, the experimental cross section curve can be recovered through Monte Carlo simulations of a single RPP as opposed to the Heaviside step function obtained when using a standard single sensitive volume approach.

Combined use of heavy ion and proton test data in the determination of a GaAs Power MESFET critical charge and sensitive depth

Abstract: A method is proposed that usesthe fundamental physical differences between direct and indirect energy deposition processes to obtain accurate values of the sensitive volume (SV) thickness and critical charge of electronic devices. The intention is to calibrate a unified model capable of describing both heavy ion and proton test data through Monte Carlo (MC) simulations and therefore also suitable for performing on-board predictions. The method was applied toavailable test data from a Gallium Arsenide (GaAs) power MESFET currently on board the MetOp-A Earth-observation mission, and results were contrasted with the measured on-board time to failure period.

Perspectives for provision of high quality space radiation environment data using the Energetic Particle Telescope (EPT)

Abstract: Models of energetic electrons and protons at low altitudes in space display significant discrepancies. In this paper the possible causes of the observed differences between the most frequently used models are discussed, including instrument-induced data inaccuracy. In parallel, on the basis of simulations and in-beam experimental results, solutions to the instrumentation issues are described focusing on the implementation of these into the Energetic Particle Telescope.