Electronic devices of industrial interest for nano-satellite applications, have been irradiated to assess their reliability to single event effects (SEEs) caused by neutron irradiation at ISIS UK through the NEUTRON GATE of ISIS@MACH ITALIA Research Infrastructure
Micro- and nano-satellites, i.e., small satellites with overall mass of tens of kilograms, are becoming of increasing interest for the scientific and industrial communities. By reducing the mass of the satellite, the high cost associated to its launch into the upper atmosphere and space is also reduced and, in turn, this allows to have “constellations” (hundreds of) of small satellites which provide more precise information, e.g. by gathering data from multiple locations, compared with few larger satellites. The cost of small satellites can be reduced further by using commercial off-the-shelf (COTS) electronic devices, as opposed to more costly and custom-made one.
The resistance to Single Event Effects (SEEs) is amongst the features that COTS components need to display to be considered as highly reliable and viable alternatives for the industry of small satellites. SEEs are faults in the hardware and in the firmware of an electronic device as the result of currents induced by the ionising interaction of cosmic rays and high-energy particles with the device itself. Such particles can be either charged ions, or of neutral charge such as high-energy (MeV) neutrons.
By using the ISIS@MACH ITALIA (IMI) Unit University of Roma Tor Vergata researchers of INFN Roma 3, Thales Alenia Space have investigated the robustness of new industrial COTS devices using the Chipir beamline at ISIS through the IMI Neutron Gate. Campolo (Thales Alenia Space Italia ) commented “xxxxxxxxx”. Paolo Branchini (INFN and University of Roma TRE) said that “the main purpose of the
experiment was to make an accurate diagnosis of what are the neutron faults produced in Si Chip. This study is particularly relevant since low energy protons and ions could be filtered out exploiting local electronic shielding which in turns would generate secondary neutrons. The results of ion irradiation previously performed on the same device at the INFN – Laboratori Nazionali del Sud complement this experiment and allow us to put in place a strategy to minimize the radiation damage of the chip”. Neutron experiments were performed at the ChipIr beamline at the ISIS Neutron and Muon Source (UK), where the atmospheric neutron flux is magnified by about a billion times. This allows accelerated tests of electronic devices where, after just few seconds the exposure to neutron radiation is the same that the same device would experience in tens of years of operations.
Within the device investigated, a programmable Fault Collection and Control Unit (FCCU) monitored the 5 integrity status of the device and provided flexible safe state control. Therefore, during the neutron experiment on ChipIr, in real time, it was possible to monitor the status of the device (figure 1). In particular, at the beginning of the irradiation measurement, one could see how the FCCU was able to reset the safe state of the device after the occurrence of a SEE, as one can appreciate from the vertical drops in the control current in the left side of the figure. However, after a longer period of irradiation, some devices were subject to a complete breakdown state where the device needed to be reset continuously, as it is possible to appreciate from the right side of figure 1. Moreover, researchers of this proposals are currently investigating if, exploiting an annealing procedure following the neutron irradiation, the device could convert back to the original working conditions.
Following a long series of successful investigations involving industrial partners and Italian institutions, this investigation has demonstrated once more the usefulness of neutron irradiation at facilities such as the ISIS Neutron and Muon Source, as well as the opportunities available using the ISIS@MACH ITALIA (IMI) Neutron Gate.
Experimental Team: Thales Alenia Space Italy, University of Rome TRE, IM@IT Unit University of Rome Tor Vergata, ISIS Facility.
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