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In this work, the heavy-ion irradiation responses of MgO-Nd 2 Zr 2 O 7 (M-NZO) composite ceramics used for inert matrix fuel were experimentally investigated. And the micro and macro radiation damage of M-NZO samples was systemically unveiled after 5 MeV Xe20+ irradiation and quantified by two exposure units, displacements per atom (dpa) and phonons per atom (ppa). The newly ppa represent the number of phonon modes available in the radiated material, which are high relative to thermal properties and the resulting morphological fragmentation after irradiation. In detail, MgO phase mostly retains its pristine structure without extensive amorphization irradiated at high dpa values, meanwhile, Nd 2 Zr 2 O 7 phase also presents satisfactory radiation resistance through the distinctive order-disorder structural transformations that alleviate radiation-induced strain. Besides, MgO grains with lower ppa value dissipate ions energy more efficiently than Nd 2 Zr 2 O 7 , and exhibit higher radiation tolerance at macroscopic morphological scale. Overall, M-NZO composite ceramics have good radiation tolerance under heavy-ion bombardment, in which the lower ppa value and higher thermal conductivity of MgO make itself possess superior resistance to irradiation-induced damage than Nd 2 Zr 2 O 7. [ABSTRACT FROM AUTHOR]

With the rapid advancement of information technology, microelectronic devices have found widespread applications in critical sectors such as nuclear power plants, aerospace equipment, and satellites. However, these devices are frequently exposed to diverse radiation environments, presenting significant challenges in mitigating radiation-induced damage. Hence, this review aims to delve into the intricate damage mechanisms of microelectronic devices within various radiation environments and highlight the latest advancements in radiation-hardening techniques. The ultimate goal is to bolster the reliability and stability of these devices under extreme conditions. The review initiates by outlining the spectrum of radiation environments that microelectronic devices may confront, encompassing space radiation, nuclear explosion radiation, laboratory radiation, and process radiation. It also delineates the potential damage types that these environments can inflict upon microelectronic devices. Furthermore, the review elaborates on the underlying mechanisms through which different radiation environments impact the performance of microelectronic devices, which includes a detailed analysis of the characteristics and fundamental mechanisms of damage when microelectronic devices are subjected to total ionizing dose effects and single-event effects. In addition, the review delves into the promising application prospects of several key radiation-hardening techniques for enhancing the radiation tolerance of microelectronic devices. [ABSTRACT FROM AUTHOR]

The primary radiation damage in pure V and TiVTa concentrated solid-solution alloy (CSA) was studied using a molecular dynamics method. We have performed displacement cascade simulations to explore the generation and evolution behavior of irradiation defects. The results demonstrate that the defect accumulation and agglomeration in TiVTa CSA are significantly suppressed compared to pure V. The peak value of Frenkel pairs during cascade collisions in TiVTa CSA is much higher than that in pure V due to the lower formation energy of point defects. Meanwhile, the longer lifetime of the thermal spike relaxation and slow energy dissipation capability of TiVTa CSA can facilitate the recombination of point defects. The defect agglomeration rate in TiVTa CSA is much lower due to the lower binding energy of interstitial clusters and reduced interstitial diffusivity. Furthermore, the occurrence probability of dislocation loops in TiVTa CSA is lower than that in pure V. The reduction in primary radiation damage may enhance the radiation resistance of TiVTa CSA, and the improved radiation tolerance is primarily attributed to the relaxation stage and long-term defect evolution rather than the ballistic stage. These results can provide fundamental insights into irradiation-induced defects evolution in refractory CSAs. [ABSTRACT FROM AUTHOR]

Ionizing radiation can induce different types of DNA lesions, leading to genomic instability and ultimately cell death. Radiation therapy or radiotherapy, a major modality in cancer treatment, harnesses the genotoxic potential of radiation to target and destroy cancer cells. Nevertheless, cancer cells have the capacity to develop resistance to radiation treatment (radioresistance), which poses a major obstacle in the effective management of cancer. It has been shown that administration of platinum-based drugs to cancer patients can increase tumor radiosensitivity, but despite this, it is associated with severe adverse effects. Several lines of evidence support that activation of the DNA damage response and repair machinery in the irradiated cancer cells enhances radioresistance and cellular survival through the efficient repair of DNA lesions. Therefore, targeting of key DNA damage repair factors would render cancer cells vulnerable to the irradiation effects, increase cancer cell killing, and reduce the risk of side effects on healthy tissue. Herein, we have employed a computer-aided drug design approach for generating ab initio a chemical compound with drug-like properties potentially targeting two proteins implicated in multiple DNA repair pathways. The findings of this study could be taken into consideration in clinical decision-making in terms of co-administering radiation with DNA damage repair factor-based drugs. [ABSTRACT FROM AUTHOR]

Complex-concentrated-alloys (CCAs) are of interest for a range of applications due to a host of desirable properties, including high-temperature strength and tolerance to radiation damage. Their multi-principal component nature results in a vast number of possible atomic environments with the associated variability in chemistry and structure. This atomic-level variability is central to the unique properties of these alloys but makes their modeling challenging. We combine atomistic simulations using many body potentials with machine learning to develop predictive models of various atomic properties of CrFeCoNiCu-based CCAs: relaxed vacancy formation energy, atomic-level cohesive energy, pressure, and volume. A fingerprint of the local atomic environments is obtained combining invariants associated with the local atomic geometry and periodic-table information of the atoms involved. Importantly, all descriptors are based on the unrelaxed atomic structure; thus, they are computationally inexpensive to compute. This enables the incorporation of these models into macroscopic simulations. The models show good accuracy and we explore their ability to extrapolate to compositions and elements not used during training. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy (RT) is an essential component in the treatment regimens for many cancer patients. However, the dose escalation required to improve curative results is hindered due to the normal tissue toxicity that is induced. The introduction of radiosensitizers to RT treatment is an avenue that is currently being explored to overcome this issue. By introducing radiosensitizers into tumor sites, it is possible to preferentially enhance the local dose deposited. Gold nanoparticles (GNPs) are a potential candidate that have shown great promise in increasing the radiosensitivity of cancer cells through an enhancement in DNA damage. Furthermore, docetaxel (DTX) is a chemotherapeutic agent that arrests cells in the G2/M phase of the cell cycle, the phase most sensitive to radiation damage. We hypothesized that by incorporating DTX to GNP-enhanced radiotherapy treatment, we could further improve the radiosensitization experienced by cancer cells. To assess this strategy, we analyzed the radiotherapeutic effects on monolayer cell cultures in vitro, as well as on a mice prostate xenograft model in vivo while using clinically feasible concentrations for both GNPs and DTX. Results: The introduction of DTX to GNP-enhanced radiotherapy further increased the radiotherapeutic effects experienced by cancer cells. A 38% increase in DNA double-strand breaks was observed with the combination of GNP/DTX vs GNP alone after a dose of 2 Gy was administered. In vivo results displayed significant reduction in tumor growth over a 30-day observation period with the treatment of GNP/DTX/RT when compared to GNP/RT after a single 5 Gy dose was given to mice. The treatment strategy also resulted in 100% mice survival, which was not observed for other treatment conditions. Conclusions: Incorporating DTX to work in unison with GNPs and RT can increase the efficacy of RT treatment. Our study suggests that the treatment strategy could improve tumor control through local dose enhancement. As the concentrations used in this study are clinically feasible, there is potential for this strategy to be translated into clinical settings. [ABSTRACT FROM AUTHOR]

The ability of high-entropy alloys to resist radiation damage is rooted in their compositional complexity and associated high configurational entropy. In addition, grain boundaries within all alloys serve as effective sinks for defects. Using atomistic modeling, we investigated defect–grain boundary interaction mechanisms near ordered and amorphous grain boundaries in pure nickel and in a model, quaternary, high-entropy alloy (FeCoCrNi). Our results demonstrate that a combination of compositional complexity with amorphization of the grain boundary leads to much more efficient recombination and annihilation mechanisms. Coupling these two microstructural features results in the lowest amount of residual damage, indicating that these effects compound to increase radiation tolerance. These observations are rooted in locally dependent defect migration barriers in the high-entropy alloy and the strong trapping at both ordered and amorphous grain boundaries. [ABSTRACT FROM AUTHOR]

Objective. Determine the extent of sublethal radiation damage (SRD) in a cell population that received a given dose of radiation and the impact of this damage on cell survival. Approach. We developed a novel formalism to account for accumulation of SRD with increasing dose. It is based on a very general formula for cell survival that correctly predicts the basic properties of cell survival curves, such as the transition from the linear-quadratic to a linear dependence at high doses. Using this formalism we analyzed extensive experimental data for photons, protons and heavy ions to evaluate model parameters, quantify the extent of SRD and its impact on cell survival. Main results. Significant accumulation of SRD begins at doses below 1 Gy. As dose increases, so does the number of damaged cells and the amount of SRD in individual cells. SRD buildup in a cell increases the likelihood of complex irrepairable damage. For this reason, during a dose fraction delivery, each dose increment makes cells more radiosensitive. This gradual radosensitization is evidenced by the increasing slope of survival curves observed experimentally. It continues until the fraction is delivered, unless radiosensitivity reaches its maximum first. The maximum radiosensitivity is achieved when SRD accumulated in most cells is the maximum damage they can repair. After this maximum is reached, the slope of a survival curve, logarithm of survival versus dose, becomes constant, dose independent. The survival curve becomes a straight line, as experimental data at high doses show. These processes are random. They cause large cell-to-cell variability in the extent of damage and radiosensitivity of individual cells. Significance. SRD is in effect a radiosensitizer and its accumulation is a significant factor affecting cell survival, especially at high doses. We developed a novel formalism to study this phenomena and reported pertinent data for several particle types. [ABSTRACT FROM AUTHOR]

Ionizing radiation (IR)-induced DNA damage and repair are complex and occur at hierarchical chromatin structures; radiobiology needs to be studied from a 3D-genomic perspective. Differences in IR damage and repair throughout the 3D genome may help to explain differences in radiosensitivity. [ABSTRACT FROM AUTHOR]

Refractory tungsten-based medium- and high-entropy alloys form a promising class of strong, heat- and radiation-resistant materials for nuclear applications. Here, we systematically explore the radiation tolerance of Mo–Nb–Ta–V–W alloys using molecular dynamics simulations and a machine-learned interatomic potential. Going from pure W to W-based equiatomic binaries, ternaries, quaternary, and the quinary high-entropy alloy, we simulate the radiation damage accumulation up to 0.4–0.8 dpa through cumulative collision cascades. We find that the radiation damage and evolution are controlled by a combination of cascade-induced clustering, the balance in migration of vacancies and interstitials, and defect cluster binding energies. These mechanisms are strongly influenced by atom size, among which vanadium as the smallest atom is decisive. In pure W and alloys without V, the microstructure is characterised by large and growing interstitial dislocation loops. In stark contrast, in alloys containing V, vacancy dislocation loops are formed directly in collision cascades and the balanced migration rate of vacancies and interstitials promotes recombination and prevents growth of interstitial loops. The atom size differences also lead to clear segregation, with small atoms (V) in interstitial clusters and larger atoms (Ta, Nb) segregating around vacancy clusters. Furthermore, the small cluster sizes, formation of vacancy loops, segregation, and balanced migration in V-containing alloys lead to low swelling and an exceptionally efficient defect annealing compared to pure W and V-free alloys. Our results highlight WTaV as a promising low-activation material, where almost 90% of defects are annealed at 2000 K during 5 ns compared to < 20 % in pure W. [Display omitted] [ABSTRACT FROM AUTHOR]

We report the results of massive parallel molecular dynamics simulations of high-energy radiation damage in phosphate glasses. This damage is created by overlapping multiple 70 keV collision cascades. We quantify different aspects of radiation-induced structural changes including at different stages of damage development, including coordination numbers, cluster sizes and density. The overall trend is that radiation damage causes polymerisation of the glass network and the loss of small and isolated clusters, however the details of this response vary with different glass compositions. • Radiation damage in iron phosphate glasses causes polymerization of the PO 4 network, excluding iron-oxygen bonds. • Anomalous 5-coordinated phosphorus atoms are produced by radiation cascades at the expense of 4-coordinated atoms. • High energy 70 keV cascades severely limit the degree of recovery of the above effects compared to low energy 4 keV cascades. [ABSTRACT FROM AUTHOR]

In application scenarios such as astronautics, high-altitude aircraft, medical radiography, high-energy physics, and nuclear power plants, the irradiation resistance of electronic components is one of the basic requirements for their reliability. HfO 2 -based ferroelectric films have the advantages of high CMOS process compatibility, good miniaturizability, low operating voltage, and excellent irradiation resistance, which are the core materials for the new generation of irradiation resistance ferroelectric memories. In this paper, two kinds of metal-electrode ferroelectric capacitors, W/Hf 0.5 Zr 0.5 O 2 /W (WW) and Pt/Hf 0.5 Zr 0.5 O 2 /Pt (PP), have been prepared, and three gradient γ-irradiation experiments have been carried out on the two kinds of ferroelectric capacitors. The effect of metal electrodes on the irradiation resistance of Hf 0.5 Zr 0.5 O 2 ferroelectric thin films was carefully investigated by comparing and analyzing the statistical laws of polarization change and rectangularity change before and after irradiation of a large number of devices. The experimental results show that the WW devices have better irradiation resistance than PP devices, and we further explain the irradiation resistance mechanism by first-principle calculations and finite element analysis to verify the credibility of the experimental results. Finally, we conducted a comparative test of the fatigue and wake-up characteristics of the WW devices before and after irradiation, and the results show that the prepared W/Hf 0.5 Zr 0.5 O 2 /W devices can withstand very high total γ-dose radiation, reaching up to 13.86 Mrad(Si), and they are very suitable for the application of irradiation resistant electronics. [Display omitted] • The Hf 0.5 Zr 0.5 O 2 (HZO) thin films with outstanding ferroelectric properties were prepared. • The HZO ferroelectric thin films exhibited extremely high radiation tolerance (reaching up to 13.86 Mrad(Si)). • The effect of different metal electrodes on the irradiation resistance of HZO ferroelectric thin films was analyzed. [ABSTRACT FROM AUTHOR]

Spatially fractionated ultra‐high‐dose‐rate beams used during microbeam radiation therapy (MRT) have been shown to increase the differential response between normal and tumour tissue. Quality assurance of MRT requires a dosimeter that possesses tissue equivalence, high radiation tolerance and spatial resolution. This is currently an unsolved challenge. This work explored the use of a 500 nm thick organic semiconductor for MRT dosimetry on the Imaging and Medical Beamline at the Australian Synchrotron. Three beam filters were used to irradiate the device with peak energies of 48, 76 and 88 keV with respective dose rates of 3668, 500 and 209 Gy s−1. The response of the device stabilized to 30% efficiency after an irradiation dose of 30 kGy, with a 0.5% variation at doses of 35 kGy and higher. The calibration factor after pre‐irradiation was determined to be 1.02 ± 0.005 µGy per count across all three X‐ray energy spectra, demonstrating the unique advantage of using tissue‐equivalent materials for dosimetry. The percentage depth dose curve was within ±5% of the PTW microDiamond detector. The broad beam was fractionated into 50 microbeams (50 µm FHWM and 400 µm centre‐to‐centre distance). For each beam filter, the FWHMs of all 50 microbeams were measured to be 51 ± 1.4, 53 ± 1.4 and 69 ± 1.9 µm, for the highest to lowest dose rate, respectively. The variation in response suggested the photodetector possessed dose‐rate dependence. However, its ability to reconstruct the microbeam profile was affected by the presence of additional dose peaks adjacent to the one generated by the X‐ray microbeam. Geant4 simulations proved that the additional peaks were due to optical photons generated in the barrier film coupled to the sensitive volume. The simulations also confirmed that the amplitude of the additional peak in comparison with the microbeam decreased for spectra with lower peak energies, as observed in the experimental data. The material packaging can be optimized during fabrication by solution processing onto a flexible substrate with a non‐fluorescent barrier film. With these improvements, organic photodetectors show promising prospects as a cost‐effective high spatial resolution tissue‐equivalent flexible dosimeter for synchrotron radiation fields. [ABSTRACT FROM AUTHOR]

Primary radiation damage in hcp Zr, including both defect production in a single collision cascade and damage buildup through cascade overlap, is investigated using molecular dynamics (MD) simulations from a potential energy landscape (PEL) perspective. It is found that the material's response to an energetic particle can be understood as a trajectory in the PEL comprising a fast uphill journey and a slow downhill one. High-temperature-induced damage reduction and the difference in the radiation tolerance between metals and semiconductors can be both qualitatively explained by the dynamics of the trajectory associated with the topographic features of the system's PEL. Additionally, by comparing irradiation and heating under a nearly identical condition, we find that large atomic displacements stemming from the extreme locality of the energy deposition in irradiation events are the key factor leading to radiation damage in a solid. Finally, we discuss the advantages of the PEL perspective and suggest that a combination of the PEL and the traditional crystallographic methods may provide more insights in future work. [ABSTRACT FROM AUTHOR]

• Finite element modeling of kink-band formation in bimetallic layered composites. • Refining layers and increasing local strength differential triggers kink-banding. • Strain-hardenability of the constituent materials stabilizes kink-band formation. • Simulations naturally capture most experimentally observed features of kink-banding. Bimetallic layered composites with ultrathin layers possess high strength and hardness, and excellent shock resistance and radiation damage tolerance. However, they are prone to deformation localization and readily form kink-bands when subjected to layer parallel compression. Following this, we carried out extensive plane strain finite element finite deformation analyses to understand and rationalize the experimentally observed kink-band formation in these composites. In the calculations, both constituent materials were assumed to follow a rate-independent isotropic elastic-plastic constitutive relation with an ad-hoc thickness dependent yield strength. Our results demonstrate that in these composites, layer refinement, together with the strength differential between the layers of the constituent materials, is sufficient to trigger kink-banding. Importantly, this phenomenon occurs even in the absence of elastically stiff layers, geometrical imperfections (such as waviness of the layers), and extreme plastic anisotropy within the layers. Additionally, we performed parametric studies to investigate the individual effects of layer thickness, strength differential between the two constituent materials, and strain-hardenability of the materials on kink-band formation. The outcomes of our parametric studies reveal that the strain-hardenability of the constituent materials stabilizes the formation of kink-bands. Furthermore, it leads to a transition from the abrupt formation of through-width kink-bands to the onset and propagation of stable inclined wedge-shaped kink-bands, similar to the experimental observations. [ABSTRACT FROM AUTHOR]

High/medium entropy alloys (HEAs/MEAs) are good candidates for nuclear applications due to the excellent mechanical properties, good corrosion resistance and radiation resistance. In this work, a novel cobalt-free MEA was developed by introducing L1 2 nanoprecipitates. The microstructure evolution and radiation tolerance were evaluated after bombarded using 3 MeV Fe11+ ions at 500 °C. The evolution of nanoprecipitates was closely related to the irradiation dose, and dominated by irradiation-enhanced diffusion and ballistic dissolution mechanism. For the solid-solution MEA (without L1 2 nanoprecipitates), irradiation hardening occurred due to the irradiation-induced formation of precipitates, voids and dislocation loops. However, in MEA with L1 2 nanoprecipitates after aging, irradiation induced dissolution and reprecipitation of nanoprecipitates were observed. Different from the solid-solution MEA, the hardness kept almost unchanged in the aging sample after irradiation. The swelling rate of the solid-solution sample after irradiation is 9.4 × 10−6 %/dpa, while no swelling occurs in the aging sample under the same irradiation condition. Besides, the average size and number density of dislocation loops in the aging sample decreased by ∼ 40% and ∼ 28%, compared with the solid-solution sample. The precipitation and dissolution of nanoprecipitates substantially improved the radiation tolerance of the cobalt-free MEA. [ABSTRACT FROM AUTHOR]

Radiation damage in beam window materials limits the use of high power proton beams in high energy physics research. The alloy Ti-6Al-4V is presently used as a beam window material but a prospective alternative, Ti-15V-3Cr-3Sn-3Al has been proposed. Since both these alloys contain dual phases at room temperature, we compare the radiation damage in the α and β-phases of these two materials via primary knock-on atom (PKA) cascade simulations in the 10–40 keV energy range. At PKA energies 30 and 40 keV, the number of Frenkel pairs in the ballistic stage is higher in the β-phase of Ti-6Al-4V than that in the β-phase of Ti-15V-3Cr-3Sn-3Al almost by a factor of 2. The α-phase, of both these alloys, by far outperforms the β-phases of the two alloys, both in terms of damage during the ballistic stage and in terms of the surviving defects. The average displacement threshold energy (E d) in the α-phase of both alloys was found to be 66 eV while that in the β-phase of Ti-15-3-3 was 55 eV and in the β-phase of Ti-6-4 was 46. While the number of surviving defects is almost equal in both alloys, the vacancy and interstitial clustering mechanisms differ notably, which can impact the degree of radiation hardening and loss of ductility. Our simulations show larger vacancy and interstitial clusters form in Ti-6Al-4V as compared to that in Ti-15-3-3-3 alloy. These results indicate that Ti-15-3-3-3 alloys may be a promising candidate for next generation beam window material with a higher radiation tolerance than the existing Ti-6-4 alloy. [ABSTRACT FROM AUTHOR]

Nanolayered metals are shown to have significantly improved radiation resistance, owing to the copious interplay between their densely populated internal boundaries with irradiation-induced defects. Therefore, they have become promising candidates for structural applications in advanced nuclear reactors. Here we fabricated bulk nanolaminated graphene (in the form of reduced graphene oxide)-aluminum composite, and explored their structural and property evolution under high energy helium irradiation. We carefully designed and implemented the micro-/nano-mechanical test, so that the mechanical behavior of small scale specimens resembled that of the bulk. Compared to the unreinforced matrix, the graphene–aluminum composite showed substantially lower irradiation-induced strengthening magnitude, a considerable total elongation, smaller lattice swelling, and a completely different deformation mechanism after irradiation. A combination of detailed experimental observations and large-scale atomistic simulations indicated that both remarkable irradiation resistance and distinct mechanism of graphene–aluminum composite are related to the excellent sink strength of the graphene layers for irradiation-generated defects. This study offers a novel and effective strategy to produce scalable radiation damage-tolerant bulk metal matrix composite with meticulously tailored microstructures. Image, graphical abstract [ABSTRACT FROM AUTHOR]

CMOS image sensors (CISs) hardened by design against total ionizing dose (TID) are exposed to neutron fluences beyond 1014 n(1 MeV)/cm2. Neutron-irradiated devices show a huge increase in the dark current affecting uniformly the pixel array which leads to Gaussian shape dark current distributions. Moreover, random telegraph signal behavior is hardly detectable at these very high neutron fluences since the fluctuation amplitudes are hidden by the dark current shot noise. It is observed that neutrons induce a change in the depleted volume in impacted photodiodes because of doping profile modifications which are responsible for the decrease in the charge-to-voltage conversion factor and quantum efficiency. Even if neutron-induced degradations affect all the image sensor performances, results show that this technology is still functional after having absorbed 8.1 × 1014 n(1 MeV)/cm2. Image sensors are still able to capture an image without significant degradation compared to nonirradiated devices. Such TID radiation-hardened CISs are thus highly promising for applications where both high TID and high neutron fluence radiation tolerance are required. [ABSTRACT FROM AUTHOR]

Silicon (Si) single-photon avalanche diode (SPAD) arrays sensitive to the 400- to 900-nm wavelength range have been studied for a number of uses due to their high detection efficiency; zero readout noise; low timing jitter; mechanical robustness; low-voltage (< 50 V) operation; mass producibility; and low size, weight, power, and cost. As with all solid-state detectors, however, they are susceptible to damage by radiation, with displacement damage by energetic particles being the primary concern for many applications. This article reports the results of low-dose-rate neutron irradiation from an americium–beryllium (AmBe) source on a 256×256 array of 10-μm active diameter SPADs, each with live recording of their dark count rate (DCR), up to a cumulative displacement damage dose equivalent to that delivered by a 1-MeV neutron fluence of 5.69 ⋅ 109 cm−2 in Si (11.59 TeV/g). A small fraction (~2.57%) of the SPADs in the array experienced a significant step increase in their DCR, which we ascribe to displacement damage. The remainder experienced a far more gradual and subdued increase. For this reason, an operational concept for SPAD arrays, whereby SPADs that begin to exhibit a step increase in DCR are disabled, should significantly extend the useful performance of such arrays in radiation environments. We report the surviving proportion of an array implementing such an operational concept per unit dose and its DCR. [ABSTRACT FROM AUTHOR]

Nanostructured materials with amorphous intergranular films (AIFs) have demonstrated superior strength and ductility. Their radiation tolerance is expected to be high as the large fraction of interfacial volume efficiently sinks radiation-induced defects. Here we demonstrate how a crystalline-amorphous system (nanocrystalline Cu with Zr-doped AIFs) responds to continuous irradiation with molecular dynamics simulations. We propose a diffusion model that well characterizes the cascade-driven mixing process, and reveal that the spread of Zr distribution scales linearly with the damage level. The exceptional radiation resistance is attributed to the interfaces acting as sustainable defect sinks, Zr mixing into the bulk to enhance local defect annihilation due to solute-interstitial dragging, and Zr impeding radiation-enhanced grain growth by restraining AIFs from migration and maintaining interface stiffness. These findings suggest that AIF-engineered systems hold promise as highly radiation-tolerant materials with strong structural stability and self-healing capability under radiation damage. [ABSTRACT FROM AUTHOR]

Nanocrystalline metals are promising radiation tolerant materials due to their large interfacial volume fraction, but irradiation-induced grain growth can eventually degrade any improvement in radiation tolerance. Therefore, methods to limit grain growth and simultaneously improve the radiation tolerance of nanocrystalline metals are needed. Amorphous intergranular films are unique grain boundary structures that are predicted to have improved sink efficiencies due to their increased thickness and amorphous structure, while also improving grain size stability. In this study, ball milled nanocrystalline Cu-Zr alloys are heat treated to either have only ordered grain boundaries or to contain amorphous intergranular films distributed within the grain boundary network, and are then subjected to in situ transmission electron microscopy irradiation and ex situ irradiation. Differences in defect density and grain growth due to grain boundary complexion type are then investigated. When amorphous intergranular films are incorporated within the material, fewer and smaller defect clusters are observed while grain growth is also limited, leading to nanocrystalline alloys with improved radiation tolerance. Image, graphical abstract [ABSTRACT FROM AUTHOR]

This work is a first assessment of the radiation tolerance of the nanolayered ternary carbides (MAX phases), Zr 3 AlC 2 , Nb 4 AlC 3 and (Zr 0.5 ,Ti 0.5) 3 AlC 2 , using proton irradiation followed by post-irradiation examination based primarily on x-ray diffraction analysis. These specific MAX phase compounds are being evaluated as candidate coating materials for fuel cladding applications in advanced nuclear reactor systems. The aim of using a MAX phase coating is to protect the substrate fuel cladding material from corrosion damage during its exposure to the primary coolant. Proton irradiation was used in this study as a surrogate for neutron irradiation in order to introduce radiation damage into these ceramics at reactor-relevant temperatures. The post-irradiation examination of these materials revealed that the Zr-based 312-MAX phases, Zr 3 AlC 2 and (Zr 0.5 ,Ti 0.5) 3 AlC 2 have a superior ability for defect-recovery above 400 °C, whilst the Nb 4 AlC 3 does not demonstrate any appreciable defect recovery below 600 °C. Density functional theory calculations have demonstrated that the structural differences between the 312 and 413-MAX phase structures govern the variation of the irradiation tolerance of these materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were employed to study radiation damage created in collision cascades in L1 0 TiAl intermetallic compound and fcc Ti-50at.%Al disordered solid solution. Either Al or Ti primary knock-on atoms (PKA) with PKA energy 5 keV ⩽ E PKA ⩽ 20 keV were initiated in the two materials at temperature T ranging from 100 K to 1200 K. From 36 to 48 different cascades for each ( E PKA , T) set were simulated in order to emulate an isotropic spatial and random temporal distribution of PKAs, generate representative sampling and obtain statistically reliable quantitative results. The number of Frenkel pairs, 〈 N FP γ - TiAl 〉 and 〈 N FP Ti - 50 Al 〉 , formed in L1 0 TiAl intermetallics and Ti-50at.%Al disordered solid solution, respectively, and averaged over collision cascades with the same ( E PKA , T) was used as a quantitative measure of radiation resistance against primary damage formation. It is shown that the relationship 〈 N FP γ - TiAl 〉 ⩽ 〈 N FP Ti - 50 Al 〉 is fulfilled under all simulation conditions, i.e. L1 0 ordered crystal structure of TiAl intermetallics is essential for its high radiation tolerance. However, a relatively high resistance to the formation of primary radiation defects is retained even after complete disordering of L1 0 TiAl that points out to the existence of additional mechanisms contributing to its radiation tolerance. [ABSTRACT FROM AUTHOR]

In this paper, different sized NMOS devices, with the drain and gate terminals connected to 1.8 V and other terminals connected to ground potential, were irradiated. The effects of irradiation were investigated on the devices with either proper configuration of the drain and source terminals or with them reversed. Differences between the measured results corresponding to each configuration are attributed to different trap concentrations on the drain and source sides of STI. This idea has been tested by TCAD simulations, as well, and similar results have been obtained. [ABSTRACT FROM AUTHOR]

Abstract A molecular dynamics study of radiation damage created in collision cascades in D0 19 Ti 3 Al intermetallic compound and a Ti-Al binary disordered solid solution with the same chemical composition is carried out. Collision cascades are initiated by either Al or Ti primary knock-on atoms (PKA) with PKA energy 5 keV ≤ E P K A ≤ 20 keV in the two materials at temperature T ranging from 100 K to 900 K. A series of at least 32 different cascades for each ( E P K A , T) set was simulated in order to imitate an isotropic spatial and random temporal distribution of PKAs, generate representative sampling and obtain statistically reliable quantitative results. The numbers of Frenkel pairs, 〈 N F P α 2 〉 and 〈 N F P α 〉 , formed in D0 19 Ti 3 Al intermetallics and Ti-25at.%Al disordered solid solution, respectively, were averaged over collision cascades with the same ( E P K A , T) and used to quantify the radiation resistance against primary damage formation. It is shown that the relationship 〈 N F P α 2 〉 ≤ 〈 N F P α 〉 is satisfied under all simulation conditions, i.e. D0 19 ordered crystal structure of Ti 3 Al intermetallics is an important feature affecting its radiation tolerance. Nevertheless, a relatively high resistance against the formation of primary radiation defects has been retained even after complete disordering of D0 19 Ti 3 Al, which points out to the existence of additional mechanisms governing its radiation tolerance. Highlights • High radiation tolerance of α 2 -Ti 3 Al is determined by its ordered crystal structure. • Primary damage in Ti 3 Al is compared with that in Ti-25at.%Al disordered solid solution. • Notable fraction of high radiation tolerance of Ti 3 Al is retained after disordering. • Other PKA energy dissipation mechanisms contribute to radiation tolerance of α 2 -Ti 3 Al. [ABSTRACT FROM AUTHOR]

Ion accelerators have been used by material scientists for decades to investigate radiation damage formation in nuclear materials and thus to emulate neutron-induced changes. The versatility of conditions in terms of particle energy, dose rate, fluence, etc., is a key asset of ion beams allowing for fully instrumented analytical studies. In addition, very short irradiation times and handling of non-radioactive samples dramatically curtail the global cost and duration as compared to in-reactor testing. Coupling of two or more beams, use of heated/cooled sample holders, and implementation of in situ characterization and microscopy pave the way to real time observation of microstructural and property evolution in various extreme radiation conditions more closely mimicking the nuclear environments. For these reasons, multiple ion beam facilities have been commissioned worldwide. In France, under the auspices of the Université Paris-Saclay, the JANNuS platform for 'Joint Accelerators for Nanosciences and Nuclear Simulation' comprises five ion implanter and electrostatic accelerators with complementary performances. At CSNSM (CNRS & Univ Paris-Sud, Orsay), a 200 kV Transmission Electron Microscope is coupled to an accelerator and an implanter for in situ observation of microstructure modifications induced by ion beams in a material, making important contribution to the understanding of physical phenomena at the nanoscale. At CEA Paris-Saclay, the unique triple beam facility in Europe allows the simultaneous irradiation with heavy ions (like Fe, W) for nuclear recoil damage and implantation of a large array of ions including gasses for well-controlled modelling-oriented experiments. Several classes of materials are of interest for the nuclear industry ranging from metals and alloys, to oxides or glasses and carbides. This paper gives selected examples that illustrate the use of JANNuS ion beams in investigating the radiation resistance of structural materials for today's and tomorrow's nuclear reactors. [ABSTRACT FROM AUTHOR]

Abstract The current understanding of radiation tolerance of Silicon Photomultipliers (SiPMs) is reviewed. Radiation damage in silicon sensors is briefly introduced, surface and bulk effects are separately addressed. Results on the operation of irradiated SiPMs with X-ray, gamma, electron, proton and neutron sources are presented. The most critical effect of radiation on SiPMs is the increase of dark count rate, which makes it impossible to resolve signals generated by a single photon from the noise. Methods to characterize irradiated SiPMs after their single photo-electron resolution is lost are discussed. Due to the important similarity in the operation below the breakdown voltage, studies on radiation damage of avalanche photo-diodes (APD) are also reviewed. Finally, ideas are presented on how to approach the development of radiation hard SiPMs in the future. [ABSTRACT FROM AUTHOR]

The ability of nanoporous metals to avoid accumulation of damage under ion beam irradiation has been the focus of several studies in recent years. The width of the interconnected ligaments forming the network structure typically is on the order of tens of nanometers. In such confined volumes with high amounts of surface area, the accumulation of damage (defects such as stacking-fault tetrahedra and dislocation loops) can be mitigated via migration and annihilation of these defects at the free surfaces. In this work, in situ characterization of radiation damage in nanoporous gold (np-Au) was performed in the transmission electron microscope. Several samples with varying average ligament size were subjected to gold ion beams having three different energies (10 MeV, 1.7 MeV and 46 keV). The inherent radiation tolerance of np-Au was directly observed in real time, for all ion beam conditions, and the degree of ion-induced damage accumulation in np-Au ligaments is discussed here. [ABSTRACT FROM AUTHOR]

Abstract Fondazione Bruno Kessler (FBK, Trento, Italy) has recently delivered its first 50 μ m thick production of Ultra-Fast Silicon Detectors (UFSD), based on the Low-Gain Avalanche Diode design. These sensors use high resistivity Si-on-Si substrates, and have a variety of gain layer doping profiles and designs based on Boron, Gallium, Carbonated Boron and Carbonated Gallium to obtain a controlled multiplication mechanism. Such variety of gain layers will allow identifying the most radiation hard technology to be employed in the production of UFSD, to extend their radiation resistance beyond the current limit of ϕ ∼ 1015 n e q /cm 2. In this paper, we present the characterisation, the timing performance, and the results on radiation damage tolerance of this new FBK production. [ABSTRACT FROM AUTHOR]

Highlights • Water intakes of radiation damaged CR-39 polymer. • Water intakes increases with the radiation damage systematically. • Water intakes by CR-39 is due to its porosity. • SEM images support thickness measurements. Abstract Swelling of CR-39 nuclear track detectors due to fission fragment and alpha particle induced damage is studied through thickness measurements. Exposure periods for irradiation damage spans from 1 to 350 h. In follow-up experiments, swelling of irradiated CR-39 detectors due to their soaking in water for a wide range of periods, from 1.5 h to 6 months, is also investigated. It is observed in a quantitative manner that the water incorporation by CR-39 nuclear track or radiation detectors during soaking increases quickly with increase of the radiation damage up to soaking time of 60 days after which thickness increases with slower rate up to soaking of 120 days. Thicknesses of detectors remain practically same between soaking of 120–180 days. It is concluded that the interaction of radiations breaks the atomic bonds in surface layer of CR-39 leading to the emission of gases (H 2 , C 2 H 2 , CO 2 and O 2) which makes the exposed CR-39 porous. During soaking water is incorporated in the empty space in CR-39. Based on measurements, dynamic and static regimes are characterized explaining the dependence of swelling in soaking on the pre-soaking radiation damage. Unswellable CR-39 polymer track detectors (at room temperature) become swellable when the radiation exposure exceeds a certain limit. Thickness measurement results are supported by scanning electron microscopy (SEM) of undamaged and damaged CR-39 samples. [ABSTRACT FROM AUTHOR]

Abstract Thirteen austenitic stainless steels, nickel-base alloys, and ferritic alloys were irradiated using 2 MeV protons at 360 °C to a damage level of 2.5 displacements per atom (dpa). Comprehensive microstructural characterization was performed for irradiation-induced features, including dislocation loops, voids, precipitates, and radiation induced segregation (RIS). Dislocation loops formed in all alloys except 14YWT, while voids were observed in alloys 316 L, 310, C22, and 14YWT. Irradiation-induced formation of γ′ precipitates was observed in alloys 316 L, 310, 800, and 690; the irradiation-enhanced, long-range ordered Ni 2 Cr phase (Pt 2 Mo-type) was observed in alloys 690, C22, 625, 625Plus, 625DA, and 725; and G-phase was observed in alloy T92. No irradiation-induced precipitates were observed in alloys X750, 718 or 14YWT. Precipitation of the γ′ phase can be understood through segregation and clustering of Si, Al, and Ti. Overall, austenitic stainless steels are generally susceptible to irradiation damage in the form of loops, voids, precipitates, and RIS. Ni-base alloys have this same type of dislocation loops and RIS behaviors but are more resistant to void swelling. Ferritic alloys showed better resistance to loop formation, void swelling and irradiation-induced precipitation. From the degree of irradiation-induced microstructural change, alloy T92 was identified as the most radiation resistant among these alloys. [ABSTRACT FROM AUTHOR]

While nanotwinned metals have been proven to show excellent mechanical properties, they are generally anticipated to be less effective in the alleviation of radiation damage. However, recent in situ studies have indicated that some nanotwinned metals exhibit unprecedented radiation tolerance, and the unexpected self‐healing of twin boundaries in response to radiation was observed. To reveal the underlying atomic mechanisms, we performed long‐time molecular dynamics simulations to study the dynamic interaction between twin boundary and some typical radiation‐induced point defects, including vacancy cluster and self‐interstitial atoms. The defective structures of coherent twin boundary which contains incoherent twin segment or self‐interstitial atoms are considered, and these structure features are found to effectively improve the ability of twin boundary to act as a sink for point defects. [ABSTRACT FROM AUTHOR]

The radiation hardness of amorphous Ge2Sb2Te5 phase-change random-access memory material has been elucidated by ab initio molecular-dynamics simulations. Ionizing radiation events have been modeled to investigate their effect on the atomic and electronic structure of the glass. Investigation of the short- and medium-range order highlights a structural recovery of the amorphous network after exposure to the high-energy events modeled in this study. Analysis of the modeled glasses reveals specific structural rearrangements in the local atomic geometry of the glass, as well as an increase in the formation of large shortest-path rings. The electronic structure of the modeled system is not significantly affected by the ionizing radiation events, since negligible differences have been observed before and after irradiation. These results provide a detailed insight into the atomistic structure of amorphous Ge2Sb2Te5 after irradiation and demonstrate the radiation hardness of the glass matrix. [ABSTRACT FROM AUTHOR]

Mg is known to be highly vulnerable to irradiation damage. Here we show, via in situ Kr ion irradiation studies inside a transmission electron microscope, that both defect density and size have been reduced substantially in porous Mg compared to dense coarse-grained Mg counterpart. Both prism and basal dislocation loops form at low dose in coarse-grained Mg, but basal loops dominate at a higher dose level. Meanwhile, in irradiated porous Mg, basal loops prevail throughout the entire irradiation process. Mechanisms that lead to enhanced irradiation tolerance of porous Mg are discussed. [ABSTRACT FROM AUTHOR]

Epitaxial nanotwinned Cu film with abundant nanovoids surrounding domain boundaries was subjected to Kr ++ ion irradiation inside a transmission electron microscope at various dose rates. Irradiation-induced defect clusters distributed preferentially near domain boundaries during the early stage of radiation. Meanwhile, the pre-existing nanovoids continuously shrank. This study suggests that the defect network enabled by the unique combination of nanotwins and nanovoids may significantly enhance the radiation tolerance of metallic materials. [ABSTRACT FROM AUTHOR]

We present a new method of characterizing damage arising from a-recoil cascades in amorphous materials including glasses. The approach taken is topological, yielding information on atom connectivity and utilizing complete sets of orthogonal functions (spherical harmonics and Hermite functions) to compute order parameters. The utility of our new approach is demonstrated by first applying it to models of radiation-damaged crystalline zircon, enabling validation against the standard defect counting method (Wigner-Seitz). We then apply it to a simple model of a glass, obtained by supercooling a Lennard-Jones liquid, for which defect counting methods are inapplicable. The method shows great promise for use in characterizing damage in more complicated glasses, particularly those of interest in the immobilization of nuclear waste, and when used in conjunction with nonequilibrium computer simulation could be a powerful tool to elucidate experimental data on the radiation tolerance of such wasteforms. [ABSTRACT FROM AUTHOR]

We report a significant grain size effect on radiation tolerance of nanocrystalline Mo under He ion irradiation. Irradiation-induced dislocation loops mainly contribute to the irradiation-induced hardening of Mo films with grain size of > 90 nm, while few such loops in those with grain size of < 90 nm. The hardness increment after irradiation decreases with decreasing the grain size, and approaches zero at the grain size of 25 nm. Also, the size and the density of irradiation-induced He bubbles decrease as the grain size decreases. This observation provides direct evidence that nanocrystalline body-centered-cubic metals have greater radiation tolerance than their ultra-fine-grained or coarse-grained counterparts. [ABSTRACT FROM AUTHOR]

The proposed Circular Electron Positron Collider (CEPC) will be primarily aimed for precision measurements of the discovered Higgs boson. Its innermost vertex detector, which will play a critical role in heavy-flavor tagging, must be constructed with fine-pitched silicon pixel sensors with low power consumption and fast readout. CMOS pixel sensor (CPS), as one of the most promising candidate technologies, has already demonstrated its excellent performance in several high energy physics experiments. Therefore it has been considered for R&D for the CEPC vertex detector. In this paper, we present the preliminary studies to improve the collected signal charge over the equivalent input capacitance ratio ( Q / C ) , which will be crucial to reduce the analog power consumption. We have performed detailed 3D device simulation and evaluated potential impacts from diode geometry, epitaxial layer properties and non-ionizing radiation damage. We have proposed a new approach to improve the treatment of the boundary conditions in simulation. Along with the TCAD simulation, we have designed the exploratory prototype utilizing the TowerJazz 0.18 μm CMOS imaging sensor process and we will verify the simulation results with future measurements. [ABSTRACT FROM AUTHOR]

We have developed n + -in-p pixel sensors to obtain highly radiation tolerant sensors for extremely high radiation environments such as those found at the high-luminosity LHC. We have designed novel pixel structures to eliminate the sources of efficiency loss under the bias rails after irradiation by removing the bias rail out of the boundary region and routing the bias resistors inside the area of the pixel electrodes. After irradiation by protons with the fluence of approximately 3 × 10 15 n eq / cm 2 , the pixel structure with the polysilicon bias resistor and the bias rails removed far away from the boundary shows an efficiency loss of < 0.5 % per pixel at the boundary region, which is as efficient as the pixel structure without a biasing structure. The pixel structure with the bias rails at the boundary and the widened p-stop's underneath the bias rail also exhibits an improved loss of approximately 1% per pixel at the boundary region. We have elucidated the physical mechanisms behind the efficiency loss under the bias rail with TCAD simulations. The efficiency loss is due to the interplay of the bias rail acting as a charge collecting electrode with the region of low electric field in the silicon near the surface at the boundary. The region acts as a “shield” for the electrode. After irradiation, the strong applied electric field nearly eliminates the region. The TCAD simulations have shown that wide p-stop and large Si–SiO 2 interface charge (inversion layer, specifically) act to shield the weighting potential. The pixel sensor of the old design irradiated by γ -rays at 2.4 MGy is confirmed to exhibit only a slight efficiency loss at the boundary. [ABSTRACT FROM AUTHOR]

Photomultiplier tubes, in particular multianode photomultiplier tubes, are often used in current accelerator-based nuclear and particle physics experiments for spatially resolved detection of single photons. With increasing luminosity and harsh radiation background, the radiation hardness of these sensors plays an increasingly important role. In an extensive experimental study we have investigated the effects of neutron irradiation, using a fission neutron source, and energetic 60Co γ -irradiation on commercially available Hamamatsu H12700/H8500 MAPMTs. In addition, individual components were irradiated, such as their glass windows and voltage dividers. Additionally, a p -terphenyl based wavelength shifting coating, which can be applied on the MAPMT window to enhance the photon yield, was also tested for its radiation tolerance. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiSiN/CrN coatings with different Si and bias voltage have been deposited for He irradiation. • Amorphization and bubbles were observed in irradiated coatings which led to softening effect and hardening effect, respectively. • The layer interface could effectively increase the radiation tolerance of nano-amorphous coatings. • Coherent interface formed by epitaxial growth reduced the bubble density at layer interface and lowered the risk of interface embrittlement. Interface engineering such as grain refinement, multilayer structure was reported to be efficient strategy to enhance the irradiation tolerance by promoting the defects annihilation. However, rapid accumulation of helium atoms at interface would lead to high density bubbles and induce interface crack. In this study, we propose a new strategy to address the root causes of bubble formation by releasing He through the designed coherent interface (CI) which is formed by epitaxial growth between two sublayers without sacrifice the mechanical properties. To reveal the enhancement of CI on the irradiation tolerance, the mechanical properties and microstructure evolution of TiSiN/CrN multilayers have been investigated before and after He+ irradiation. TiSiN/CrN coatings reveal obvious amorphization at top-surface and large amount of bubbles have been observed at interfaces. The variation of hardness of the irradiated coatings depends on the competition between softening effect and hardening effect, induced by amorphization and bubble respectively. With the formation of CI across the sublayers, He atoms diffuse through the CI to deeper area beyond the ion projected range, decreasing density and size of the bubble at layer interface. Therefore, we present a new strategy of designing protective multilayer coatings for nuclear reactor through the introduction of CI. [ABSTRACT FROM AUTHOR]

We investigate the radiation response of nanotwinned Cu by using in situ Kr ion irradiation technique inside a transmission electron microscope. In comparison with coarse grained Cu, nanotwinned Cu exhibits smaller defect size and lower defect density. In situ studies also show that twin boundaries effectively remove a large number of defect clusters. The life time of defect clusters in nanotwinned Cu is very different from that in its coarse grained counterpart. This study provides further evidence on twin-boundary enabled radiation tolerance in nanotwinned metals. [ABSTRACT FROM AUTHOR]

Iron phosphate glass (IPG) has gained recent interest for use in encapsulating radioactive waste for long term storage. In this work, we investigate 5 different compositions of iron phosphate glass. We consider amorphous structures of 3 known crystalline phases: Fe 2+ Fe 2 3 + (P 2 O 7 ) 2 , Fe 4 3 + (P 2 O 7 ) 3 and Fe 3+ (PO 3 ) 3 , and structures of IPG (40 mol% Fe 2 O 3 and 60 mol% P 2 O 5 ), with 4% and 17% Fe 2+ ion concentrations. Using constant volume molecular dynamics (MD), we quench a set of structures for each glass composition, to find the optimal density structure. We found that the lowest energy structures of IPG with 4% and 17% concentration of Fe 2+ , have a density of 3.25 and 3.28 g/cm 3 respectively. This is slightly higher than the experimentally measured values of 2.9 and 2.95 g/cm 3 respectively. We also estimate an upper and lower bound on the melting temperatures of each glass, then for each glass, we simulate radiation damage cascades at 4 keV. The cascade structures can be in the form of either a concentrated thermal spike or more diffuse with sub-cascade branching. We found that the glass compositions with a higher Fe/P atomic ratio, contained a greater number of displacements after the cascade. We also found that the IPG with 4% Fe 2+ , contained slightly fewer displacements than the IPG with 17% Fe 2+ . This is consistent with our previous work, which showed that the threshold displacement energies are lower for glasses with a lower Fe 2+ content. In all the simulations, many PO 4 polyhedra are destroyed during the early stages of irradiation, but recover strongly over a time scale of picoseconds, leaving very few over or under co-ordinated P atoms at the end of the ballistic phase. This is in contrast to recent work in apatite. The strong recovery indicates that phosphate glasses with a low Fe 2+ content could be good materials for waste encapsulation. [ABSTRACT FROM AUTHOR]

We studied the heavy ion radiation tolerance of amorphous silicon oxycarbide (SiOC) alloys byin situKr ion irradiation within a transmission electron microscopy. The amorphous SiOC thin films were grown via co-sputtering from SiO2and SiC targets on a surface-oxidized Si (100) substrate. These films were irradiated by 1 MeV Kr ions at both room temperature and 300 °C with damage levels up to 5 displacements per atom (dpa). TEM characterization shows no sign of crystallization, void formation or segregation in all irradiated samples. Our findings suggest that SiOC alloys are a class of promising radiation tolerant materials. [ABSTRACT FROM PUBLISHER]

The current ATLAS Tile Calorimeter read-out system is scheduled for replacement around 2023 due to old age and higher performance needs. The new proposed system is designed to be radiation tolerant, modular, redundant and reconfigurable. To achieve full detector read-out, Kintex-7 FPGAs from Xilinx will be used, in addition to multiple 10 Gb/s optical read-out links. During 2015/2016, a hybrid demonstrator system including the new read-out system will be installed in one slice of the ATLAS Tile Calorimeter to evaluate the new design. This paper describes different firmware strategies along with their integration in the demonstrator in the context of high reliability protection against hardware malfunction and radiation induced errors. [ABSTRACT FROM AUTHOR]

The planned upgrade of the LHC accelerator at CERN, namely the high luminosity (HL) phase of the LHC (HL-LHC foreseen for 2023), will result in a more intense radiation environment than the present tracking system that was designed for. The required upgrade of the all-silicon central trackers at the ALICE, ATLAS, CMS and LHCb experiments will include higher granularity and radiation hard sensors. The radiation hardness of the new sensors must be roughly an order of magnitude higher than in the current LHC detectors. To address this, a massive R&D program is underway within the CERN RD50 Collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” to develop silicon sensors with sufficient radiation tolerance. Research topics include the improvement of the intrinsic radiation tolerance of the sensor material and novel detector designs with benefits like reduced trapping probability (thinned and 3D sensors), maximized sensitive area (active edge sensors) and enhanced charge carrier generation (sensors with intrinsic gain). A review of the recent results from both measurements and TCAD simulations of several detector technologies and silicon materials at radiation levels expected for HL-LHC will be presented. [ABSTRACT FROM AUTHOR]

A focused MeV proton beam at the Lund Ion Beam Analysis Facility has been used to induce radiation damage in transmission semiconductor detectors. The damage alters the response of detectors and degrades their charge transport properties. In this work, the radiation tolerance of ultra-thin silicon PIN detectors was studied as a function of proton fluences and detector thickness using a scanning proton microprobe. The investigated detectors had thicknesses ranging between 6.5 and 22 μm, and different selected regions of each detector were irradiated with fluence up to 2 × 10 15 protons/cm 2 . The results show that the charge collection efficiency (CCE) decreases as a function of the proton fluence. Compared with non-irradiated regions, the CCE was above 94% at the lowest fluence of 2 × 10 12 protons/cm 2 for all the detectors studied. Degradation of the devices caused spectral peak shifting toward lower energies. The highest possible fluence of 2.55 MeV protons that could be used, causing only minor radiation damage, was 2 × 10 13 cm −2 for the thinnest detectors (6.5 and 10 μm) and 2 × 10 12 cm −2 for the thickest detectors (15 and 22 μm). [ABSTRACT FROM AUTHOR]

The mechanisms of ion-induced defect formation and physical characteristics promoting radiation tolerance of wide and ultra-wide bandgap semiconductors are not well-studied and understood. In contrast to gallium nitride (GaN), gallium oxide (Ga 2 O 3) can be crystallized in several polymorphs having different crystal structures and physical properties. In the preset paper, the damage buildup in wurtzite GaN as well as in corundum (α -) and monoclinic (β -) Ga 2 O 3 polymorphs bombarded at room temperature with 40 keV P+ ions is studied by Rutherford backscattering/channeling spectrometry. We demonstrate that ion-beam-induced damage formation in Ga 2 O 3 is different from that observed in GaN and dramatically depends on the polymorph type. Both Ga 2 O 3 polymorphs cannot be rendered amorphous and exhibit considerably higher damage saturation at ∼90% of the full amorphization as compared to that of GaN. Intriguing enough the metastable α -Ga 2 O 3 demonstrates considerably higher radiation resistance as compared to the most thermodynamically stable β -Ga 2 O 3 polymorph. Furthermore, our results indicate that the sample surface and dynamic annealing play a significant role in the ion-induced damage formation processes in all Ga-based compounds studied. • Kinetics of ion irradiation damage accumulation in α- and β-Ga 2 O 3 and GaN is studied. • α -Ga 2 O 3 is more susceptible to radiation damage than GaN. • α -Ga 2 O 3 is considerably higher radiation resistant then the stable β -Ga 2 O 3. • Mechanisms of radiation damage formation in the α - and β -Ga 2 O 3 are different. [ABSTRACT FROM AUTHOR]

[Display omitted] • Appling atomistic simulations to study the radiation resistance of NiFeGr. • The lattice distortion can inhibit the collection of radiation-induced defects. • The interface can provide a strong sink for trapping defects. • The intrinsic characteristics of the CSA strengthen the interface trapping effect. Atomistic simulations were applied to investigate the coupling effect of the chemical complexity of single-phase concentrated solid solution alloys (SP-CSAs) and the defect-sink effects of graphene/CSA interfaces. The radiation-induced defect evolution and radiation resistance of NiFe–graphene (NiFeGr) nanocomposite were studied via energy calculation, cascade simulation, and defect insertion method. Results show that the interface acts as a defect trap to absorb interstitials and promote the migration of point defects toward the interface. The inherent effect of the CSAs promotes defect recombination, which significantly reduces the number of residual defects. At the same time, the concentrated solid solution alloy as matrix can effectively promote the strengthening of the interface. The combination of the two effects causes no obvious temperature effect of the radiation damage, but the material still shows good radiation resistance at high temperature. Therefore, the NiFeGr nanocomposite with synergy of concentrated solid solution alloy as a matrix and defect-sink effects from graphene interfaces shows good radiation resistance and broad application prospect in nuclear engineering materials. [ABSTRACT FROM AUTHOR]