Fast radiation monitoring in FPGA-based designs

In nanoscale FPGAs, variability, aging and radiation effects significantly limit system performance and reliability, which is a relevant problem in safety-critical applications associated with long life operation products. The impact of Single Event Upsets (SEU) on system correct operation is usually estimated by the FPGA vendor. In this paper a technique for fast radiation monitoring, taking aging effects into account is proposed for FPGA-based designs. In order to monitor SEU in memory, a novel SEU sensor is proposed, reusing BRAM resources to estimate the Soft Error Rate (SER). The proposed BRAM-based sensor allows a much faster evaluation of radiation effects than the one obtained with traditional monitoring such as monitoring of the FPGA configuration memory. Simultaneous use of aging and SEU sensors enables the activation of mitigation techniques, e.g., circuit reconfiguration for a more robust functionality. Simulation and experimental results are presented, using Virtex6 and Spartan6 boards and two real-world applications - a data acquisition system for PET-based medical imaging, and a fast plant system controller for the ITER reactor. Neutron radiation tests were performed- in the Portuguese Research Reactor (RPI).