The ionizing particle shielding capability of multi-functional high-strength and low-Z composites in low earth orbit

The ionization shielding performance of orbital debris (OD) shields, containing Ultrahigh Molecular Weight Polyethylene (UHMWPE) and aramid, have been investigated. We report the SRIM-2013 numerical simulation of the protons and heavy ions interaction with the shield, based on the description of the orbital ion environment for the analogue satellite NOVASAR-1, validated by experimentation at the Australia National University’s Heavy Ion Accelerator Facility Space Radiation Beamline. The suitability of the structures as ionizing radiation shields were measured on two metrics induced in a notional commercial-off-the-shelf (COTS) Integrated Circuit chip (IC) and Radiation Hardened (RH) IC relative to a no-shield baseline: (1) change in Soft Error Rate (SER) using SER cross-section data for chip architectures published in literature, and (2) change in Total Ionizing Dose (TID) over a notional mission time frame. The analysis finds a negligible drop in SER for the RH chip architecture for any of shield architectures discussed, while a 22-33% drop in SER independent of the shield constituent materials analysed was predicted in the COTS case. A significant drop in TID (68%-83%) was predicted due to the presence of a shielding structure, with the UHMWPE shield outperforming the aramid shield by a functionally negligible 2%. • Radiation shielding capability is material independent for the configurations considered when measured in terms of reduced soft error rate in a target. • Radiation shielding capability is functionally material independent for the configurations considered when measured in terms of reduced total ionizing dose in a target, with small relative improvements predicted for materials more interactive with ionizing radiation. • Shielding is highly effective at reducing the environmentally induced total ionizing dose of a sensitive component. • The considered shields are effective at reducing the environmentally induced soft error rate in commercial-off-the-shelf microchips, but not radiation hardened microchips. • The considered shields can not sufficiently reduce the soft error rate of commercial-off-the-shelf microchips to be comparable to that of radiation hardened microchips.