Radiation Tolerant Electronics Research Articles

Deployable optics for the Buccaneer Main Mission (BMM)

AbstractDefence Science and Technology Group (DSTG) is currently preparing for the launch of the Buccaneer Main Mission (BMM) satellite, the successor to the Buccaneer Risk Mitigation Mission (BRMM). BMM hosts a high-frequency (HF) antenna and receiver to contribute to the calibration of the Jindalee Operational Radar Network (JORN). Verification of the successful deployment and stability of the large HF antenna is critical to the success of the mission. A bespoke deployable optics payload has been developed by DSTG to fulfil the dual purpose of direct verification of the deployed state of the HF antenna and capturing images of the Earth through a rotatable, dual-surfaced mirror and a variable-focus liquid lens. The payload advances research at DSTG in several fields of space engineering, including deployable mechanisms, precision actuation devices, radiation-tolerant electronics, advanced metal polishing and optical metrology. This paper discusses the payload design, material selection, trade-offs considered for the deployable optics payload and preliminary test results.

Effects of fast and thermal neutron irradiation on Ga-polar and N-polar GaN diodes

Studies of the radiation tolerance and electrical behavior of gallium nitride (GaN) based devices are important for the next generation of high-power and high-voltage electronics that may be subjected to harsh environments such as nuclear reactor and fusion facilities, particle accelerators, and post-denotation environments. In this work, we study the behavior of Ga-polar and N-polar GaN Schottky diodes before and after exposure to fast and thermal + fast neutrons. Temperature-dependent current–voltage (I–V) and circular transmission line method (CTLM) measurements were used to study the electrical characteristics. A strong reduction in reverse leakage current and an increase in differential resistance in forward bias were observed after neutron irradiation. Thermionic emission (TE), Frenkel–Poole (FP) emission, and Fowler–Nordheim (FN) tunneling models were used to explain the forward and reverse I–V characteristics pre- and post-irradiation. The study confirms that Ga-polar and N-polar GaN Schottky diodes exhibit different electrical responses to fast and thermal neutron irradiations. The reverse bias characteristics of N-polar diodes are less affected after the fast neutron irradiation compared to Ga-polar diodes, while in the forward bias region, the electrical behavior after fast and thermal neutron irradiations is similar in Ga-polar and N-polar diodes. The results indicate that the role of orientation should be considered in the design of GaN-based radiation-tolerant electronics.

Radiation-Tolerant Electronics

When thinking of radiation-tolerant electronics, many readers will think of space [...]

Ultra-low jitter clock distribution for the trigger electronics of the New Small Wheel for the ATLAS experiment

The Large Hadron Collider (LHC) at CERN plans to have a series of upgrades to increase its instantaneous luminosity to 7.5 × 1034 cm−2 s−1. The increased luminosity drastically impacts the ATLAS trigger and readout data rates. The inner-most station of the ATLAS muon spectrometer, the so-called Small Wheels is being replaced with a New Small Wheel (NSW) system, consisting of Micromegas and small-strip Thin Gap Chambers (sTGC) detectors. The on-detector radiation levels required radiation tolerant electronics. The lower radiation levels on the rim of the NSW allowed utilizing commercial electronic chips, such as Field Programmable Gate Arrays (FPGAs), in the trigger chain of the sTGC detectors. Those FPGAs require an ultra-low jitter clock for the proper operation of their Gigabit transceivers (4.8 Gb/s serial links). The initial design was based on a clock provided by a radiation tolerant ASIC designed at CERN, but due to its intrinsic jitter and consequent marginal error rate on the transmission lines, a different approach had to be chosen. An additional clock source based on commercial jitter cleaners, fanout chips and optical transmitters driving dedicated fibers was built. The new scheme provides 64 low-jitter clocks (32 main and 32 redundant) from the radiation-protected area (USA15) to the trigger electronics over 60 m of OM3 fiber.

Vacuum transistors for space travel

Nanoscale vacuum transistors fabricated on silicon carbide wafers could provide radiation-tolerant electronics for application in future spacecraft.

Radiation Tolerant Electronics

Research on radiation tolerant electronics has increased rapidly over the last few years, resulting in many interesting approaches to model radiation effects and design radiation hardened integrated circuits and embedded systems [...]

First-Principles Assessment of the Structure and Stability of 15 Intrinsic Point Defects in Zinc-Blende Indium Arsenide

Point defects are inevitable, at least due to thermodynamics, and essential for engineering semiconductors. Herein, we investigate the formation and electronic structures of fifteen different kinds of intrinsic point defects of zinc blende indium arsenide (zb-InAs ) using first-principles calculations. For As-rich environment, substitutional point defects are the primary intrinsic point defects in zb-InAs until the n-type doping region with Fermi level above 0.32 eV is reached, where the dominant intrinsic point defects are changed to In vacancies. For In-rich environment, In tetrahedral interstitial has the lowest formation energy till n-type doped region with Fermi level 0.24 eV where substitutional point defects In A s take over. The dumbbell interstitials prefer < 110 > configurations. For tetrahedral interstitials, In atoms prefer 4-As tetrahedral site for both As-rich and In-rich environments until the Fermi level goes above 0.26 eV in n-type doped region, where In atoms acquire the same formation energy at both tetrahedral sites and the same charge state. This implies a fast diffusion along the t − T − t path among the tetrahedral sites for In atoms. The In vacancies V I n decrease quickly and monotonically with increasing Fermi level and has a q = − 3 e charge state at the same time. The most popular vacancy-type defect is V I n in an As-rich environment, but switches to V A s in an In-rich environment at light p-doped region when Fermi level below 0.2 eV. This study sheds light on the relative stabilities of these intrinsic point defects, their concentrations and possible diffusions, which is expected useful in defect-engineering zb-InAs based semiconductors, as well as the material design for radiation-tolerant electronics.

Design of a 0-50 mbar pressure measurement channel compatible with the LHC tunnel radiation environment

The monitoring of cryogenic facilities often require the measurement of pressure in the sub 5’000 Pa range that are used for flow metering applications, for saturated superfluid helium, etc. The pressure measurement is based on the minute displacement of a sensing diaphragm often through contactless techniques by using capacitive or inductive methods. The LHC radiation environment forbid the use of standard commercial sensors because of the embedded electronics that are affected both by radiation induced drift and transient Single Event Effects (SEE). Passive pressure sensors from two manufacturers were investigated and a CERN designed radiation-tolerant electronics has been developed for measuring variable-reluctance sensors. During the last maintenance stop of the LHC accelerator, four absolute pressure sensors were installed in some of the low pressure bayonet heat exchangers and four differential pressure sensors on the venturi flowmeters that monitor the cooling flow of the 20.5 kA current leads of the ATLAS end-cap superconducting toroids. The pressure sensors operating range is about 1000 to 5000 Pa and the targeted uncertainty is +/- 50 Pa which would permit to measure the equivalent saturation temperature at 1.8 K within better than 0.01 K. This paper describes the radiation hard measuring head that is based on an inductive bridge, its associated radiation-tolerant electronics that is installed under the LHC superconducting magnets or the ATLAS detector cavern; and the first operational experience.

微細加工で作るフィールドエミッタアレイ～新しい応用に向けて～

Fabrications of gated field emitter array (FEA), such as Si-FEA and Spindt-type FEA, is overviewed from the conventional method to the latest one. The invention of an etch-back method makes it possible to form the gate electrode on the emitter tip, irrespective of the emitter shape, and also possible to form the multi-stacked gate electrode for beam focusing. A hafnium carbide coating can enhance the electron emission and emission lifetime, significantly. The historical Spindt-type FEA fabrication is also progressing. Using a double-layered photoresist, instead of aluminum parting layer, makes it possible to apply the multi-gate formation even on the Spindt-type FEA. These FEAs are applicable for many kinds of attractive devices, such as ultra-high sensitive image sensor, radiation tolerant electronics, and stationary X-ray source for medical applications.

(Invited) Conductive Bridging RAM (CBRAM): Then, Now, and Tomorrow

Conductive bridging RAM (CBRAM) is a resistive memory technology (RRAM) offering performance, power/energy, reliability, and cost advantages over incumbent nonvolatile memory technologies. The present article introduces the class of CBRAM in high-volume manufacturing today—subquantum CBRAM—and highlights similarities and differences between it and its predecessors. The materials requirements of subquantum CBRAM cells are described, and new insight into the switching mechanism is provided. Finally, its electrical characteristics are benchmarked, and its suitability for applications such as embedded memory, the Internet of Things (IoT), and radiation-tolerant electronics is summarized.

High accuracy wire chambers

Abstract Wire chambers are and will be a major component of present and future collider experiments. Using the precision tracking drift chambers of the ATLAS muon spectrometer and the trigger detectors of the LHCb muon spectrometer as examples, several key features of these wire chambers will be discussed. Position resolution better than 80 μm and time resolution better than 3 n s are feasible for detector systems of several 100 m 2 and several 100,000 channels. The high rate capability of the detectors and the access to cheap, radiation tolerant electronics technologies makes these detectors applicable at very high luminosity accelerators. Also the fact that these detectors can be simulated and understood in great detail will be shown.

Radiation-tolerant electronics testing of a prototype isolating preamplifier

This paper describes part of the radiation testing of an isolating preamplifier, a part of the ongoing radiation-tolerant electronics development program at SPAR Aerospace. The circuit tested was a relatively simple isolating preamplifier with floating input and output stages with individual on-board voltage converters. The circuit performance was monitored during irradiation to fully characterize the performance in realistically harsh conditions. In doing so it demonstrates some typical radiation degradation and recovery effects. This helps to prove the potential differences in results between on-line radiation testing and passive testing. SPAR has a long history of building equipment for use in hostile environments, including fusion reactors. These fusion reactors have a number of pressing design challenges that would benefit from the development of radiation-tolerant electronics. These include a large number of diagnostic signals to be taken through the cryostat and the control signals for the rather large-scale remote-handling equipment.