Introduction
Survival and successful operation of space systems in the space radiation environment cannot be ensured without careful consideration of the effects of radiation. The estimation of radiation tolerance of SDR s is of major importance. A brief but comprehensive diagram maps the impact of radiation environment.
A presentation well dipicting the effects can be found here
Radiation analysis
Degradation from TID in electronics is a cumulative, long term degradation mechanism due to ionizing radiation—mainly primary protons and electrons and secondary particles arising from interactions between these primary particles and spacecraft materials. It causes threshold shifts, leakage current and timing skews. The effect first appears as parametric degradation of the device and ultimately results in functional failure. It is possible to reduce TID with shielding material that absorbs most electrons and lower energy protons.
Degradation form TNID or displacement damage is cumulative, long-term non-ionizing damage due to protons, electrons, and neutrons. These particles produce defects mainly in optoelectronics components such as APS , CCDs, and optocouplers. Displacement damage also affects the performance of linear bipolar devices but to a lesser extent.
SEEs result from ionization by a single charged particle as it passes through a sensitive junction of an electronic device. SEEs are caused by heavier ions, but for some devices, protons can also contribute. In some cases SEEs are induced through direct ionization by the proton, but in most instances, proton induced effects result from secondary particles produced when the proton scatters off of a nucleus in the device material. Some SEEs are non-destructive, as in the case of SEU, SET, and SEFI. Single event effects can also be destructive as in the case of single event SEL, SEGR, and SEB. The severity of the effect can range from noisy data to loss of the mission, depending on the type of effect and the criticality of the system in which it occurs. Shielding is not an effective mitigator for SEEs because they are induced by very penetrating high energy particles.The preferred method for dealing with destructive failures is to use SEE-hard parts. When SEE-hard parts are not available, latch-up protection circuitry is sometimes used in conjunction with failure mode analysis.
For the total dose environment, the damage is caused by the ionization energy absorbed by the sensitive materials, measured in rad or in gray (1 gray = 100 rad). This implies that a number of ionization sources can be used for simulation of space environment at ground level. However, the total dose response is also a strong function of the dose rate. Displacement damage can be simulated for any particle by using the value of NIEL This implies that the effects of the displacement are to a first approximation, only proportional to the total energy loss through displacements and not dependent on the nature of the displacements. The single particle environment is usually simulated by the particle LET. For heavy ions this seems to be a reasonable measure of the environment as long as the particle type and energy are adjusted to produce the appropriate range of the ionization track. For protons, however, the LET is not the primary parameter since the upsets result primarily from secondary particles resulting from the interaction of proton with device’s atoms. Thus for the proton environment, the simulations should be conducted with protons of the appropriate energy.
Radiation characterization
A Radiation characterization of electronic components, planned to be used for Space applications, is produced from Organisations (ESA, NASA, etc). Information on general procedure and specially one ours are projected here
SDR
There is an increased interest in using commercially-grade SDR boards on board smaller satellites, sometimes with only some additional shielding. To achieve this, radiation test of commercial SDR boards is basic. Dividing it in two sub-projects we have the following parts: The first part is the Characterization of Radiation resistance of the SDRs The second step is a test-campaign for the best (radiation-resistant) SDR through the procedure of ESA standards to categorise the SDR in rad-hard categorisation The objective of this project is the first part of the categorization for 8 SDRs. For this reason we research the radiation each one of these boards can withstand according to the method and the materials used for its production according to previous research made and published.
Documentation
Documentation on the radiation resistance for the 8 Devices under test (SDRs ) which are used for the main project are the following.
[ADALM Pluto SDR](ADALM Pluto SDR)
[Airspy mini](Airspy mini)
[Ettus USRP B210](Ettus USRP B210)
[RTL SDR v3](RTL SDR v3)
[LimeSDR mini](LimeSDR mini)
[SDRplay duo](SDRplay duo)
For more information, visit the HTML pages.
License
radtest is implemented in the scope of SDR Makerspace, an initiative of the European Space Agency and Libre Space Foundation.
©️ 2018 Libre Space Foundation under the GPLv3.
References
Ref 6 Radiation Effects in MMIC Devices, C. Barnes and L. Selva
Ref 8 Ref 7 Ionizing-Radiation Response of the GaAs/(Al, Ga)As PHEMT: A Comparison of Gamma- and X-ray Results, D. V. Gromov*, V. V. Elesin*, S. A. Polevich*, Yu. F. Adamov**, and V. G. Mokerov**