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Overview of the NASA ETDP RHESE Program
Published in John D. Cressler, H. Alan Mantooth, Extreme Environment Electronics, 2017
Beyond RHBA, the next level of hardening electronic components is referred to as radiation hardening by design (RHBD). RHBD implies that an electronic part or board has been radiation-hardened by virtue of the component layout and circuit architecture of on-chip gates, devices, and interconnects independent of any special fabrication process or technique. Examples of RHBD techniques include using TMR strategies within the chip layout, designing dopant wells and isolation trenches into the circuit layouts, implementing error detecting and correction circuits [16], and using device spacing and decoupling design rules. Disadvantages to these techniques include the extra devices required to implement TMR, the extra power load these devices consume, and the extra chip area required to isolate devices, gates, and latches.
Soft-Error Mitigation Approaches for High-Performance Processor Memories
Published in Tomasz Wojcicki, Krzysztof Iniewski, VLSI: Circuits for Emerging Applications, 2017
Radiation-hardened microprocessors for use in aerospace or other high-radiation environments [1] have historically lagged behind their commercial counterparts in performance. The RAD750 (BAE Systems Inc., Arlington, VA), released in 2001 on a 250-nm rad-hard process, can reach 133 MHz [2]. Recent updates of this device to a 150-nm process have improved on this, but only marginally [3]. This device, built on a radiation-hardened process, lags in part due to the difficulty in keeping such processes up to date, for relatively low-volume devices [4]. The SPARC AT697 (Atmel Corp., San Jose, CA) introduced in 2003 has an operating frequency of 66 MHz, uses triple modular redundancy (TMR) for logic, and error detection and correction (EDAC) and parity protection for memory, soft-error protection [5,6]. More recent radiation hardened by design (RHBD) processors have reached 125 MHz [7]. In contrast, unhardened embedded microprocessors contemporary to these designs achieve dramatically better performance on similar generation processes. For instance, the XScale microprocessor, fabricated on a 180-nm process, operates at clock frequencies over 733 MHz [8]. Ninety-nanometer versions of the XScale microprocessors achieved 1.2 GHz [9] with the cache performance being even higher [10]. More modern designs, such as those in 32-nm cell phone system on chip (SOC) devices, are multicore, out-of-order microprocessors, running at over 1.5 GHz [11]. As portable devices have become predominant, power dissipation has become the overriding concern in microprocessor design. The most effective means to achieving low power is clock gating, which limits circuit active power dissipation by disabling the clocks to sequential circuits such as memories. In caches and other memories, this means that the operation of clocking and timing circuits must also be protected from radiation-induced failures, including erroneously triggered operations.
Steady-State Irradiation of Characterized Instruments for Nuclear Thermal Rockets Using In-Pile Experiment Apparatus
Published in Nuclear Technology, 2022
Dan C. Floyd, Tyler R. Steiner, Emily Hutchins, Richard T. Wood, N. Dianne Bull Ezell
From the available data and various debugging methods, most possible failure mechanisms can be ruled out. Currently, it is believed that the instruments experienced failure due to gamma irradiation that degraded the performance of the various electrical components comprising its circuit board. Various investigations regarding the viability of complementary metal oxide semiconductor and metal oxide semiconductor circuit board components indicate that commercial-off-the-shelf products can withstand 1 to 100 krad before failing.13 Ionizing radiation can cause charge build up that can damage the various components that comprise the circuitry of the instrument. As such, exposure to the gamma radiation present from the reactor when not operating is the probable cause of failure due to the ~0.63 krad per hour gamma flux. This gamma flux is generated due to the decay of the radioactive products produced during reactor operation. For nuclear application, radiation-hardened electronics are critical for instrument survivability.
A 100-Mrad (Si) JFET-Based Sensing and Communications System for Extreme Nuclear Instrumentation Environments
Published in Nuclear Technology, 2022
F. Kyle Reed, M. Nance Ericson, N. Dianne Bull Ezell, Roger A. Kisner, Lei Zuo, Haifeng Zhang, Robert Flammang
With the increased interest in low Earth orbit (LEO) satellites, small modular reactors (SMRs), and advanced reactors, the market for radiation-hardened (rad-hard) electronics is expected to grow as well. SpaceX alone is set to deploy a total of over 42 000 satellites throughout the next several years to form their satellite internet constellation.1 SMRs and advanced reactors are expected to increase the percentage of nuclear power generation, which presently accounts for roughly 20% of U.S.-based annual power production.2,3 Current estimates suggest that nearly 10 000 tonnes of radioactive heavy metals are contained in the spent fuel casks.4 In the United States alone, approximately 1500 dry casks were loaded in 2010 with an additional ~200 casks added each year since.5 Collectively, these applications point to an increasing future need for rad-hard electronics.
A Radiation-Tolerant Wireless Communication System for Severe Accident Monitoring Without Relying on Rad-Hardened Electronic Components
Published in Nuclear Technology, 2021
One of the approaches to avoid radiation damage is to use radiation-hardened (rad-hardened) electronic components exclusively to build monitoring systems. Preliminary investigation has revealed, however, that this approach can be prohibitively expensive due to the specialized semiconductor materials used in chip fabrication and complexities in the manufacturing and packaging processes. Furthermore, many of these rad-hardened components are based on proven (often older) technologies, and they could not match the performance offered by the latest commercial components currently on the market in terms of processing speed, memory size, and rate of power consumption that one would expect from a modern-day monitoring system.