Search Results (448)

Recent developments in particle physics require cost-effective pixel detectors capable of operating under increased energy and luminosity conditions foreseen in future collider experiments. In response, monolithic CMOS pixel sensors incorporating modern readout architectures have emerged, combining high-rate capability with substantial radiation tolerance. To optimize the performance of these sensors for application in tracking detectors, a comprehensive characterization has been done focusing on threshold and noise behavior as a function of front-end DAC tuning parameters. The effect of radiation damage has been investigated using high-intensity X-ray irradiation, followed by a detailed comparison of sensor performance before and after irradiation. The threshold distribution is observed to be uniform across the pixel matrix. Irradiation introduces a systematic shift in the threshold, with a larger impact at low-threshold configurations, while overall uniformity is preserved. In contrast, the noise remains largely stable across the parameter space. The correlation between threshold and noise is used to identify optimal operating regions, demonstrating that stable, efficient performance can be achieved across quite a wide range of configurations. These results confirm the robustness of the sensor under irradiation and its suitability for operation in radiation environments relevant to future high-energy physics experiments. Full article

The current interest in lunar exploration led by the Artemis program is pushing scientists to search for lunar water deposits directly on the surface of the Moon, using small robotic rovers. The Institute of Experimental and Applied Physics, Czech Technical University, Prague (IEAP CTU), is developing a miniature Timepix3-based detector called Neutron HardPix, which is capable of mapping water deposits using non-invasive detection of neutrons created underground by cosmic rays and thermalized by hydrogen. This neutron spectrometer measures count rate variations in thermal, epithermal and fast neutrons attributed to hydrogen abundance in the lunar subsurface, while monitoring cosmic radiation as a natural source of neutrons. Neutron HardPix is based on the miniature (<0.1 U, 130 g) radiation monitor HardPix, and has significant space heritage. Full article

Urban and peri-urban regions increasingly face climate-related pressures, competing land-use demands, and the need to expand renewable-energy infrastructure while maintaining agricultural land and landscape functions. Agrivoltaics, which combines photovoltaic energy generation with agricultural production, represents a potentially multifunctional approach to land use; however, regional GIS assessments often stop at environmental suitability surfaces without translating those results into planning-relevant cadastral inventories. This study develops and applies a planning-oriented Geographic Information System (GIS) framework for preliminary statewide agrivoltaic screening in Connecticut. Annual global solar radiation and terrain slope were integrated through a weighted suitability model, while incompatible land-cover classes were treated as hard exclusions through a binary land-cover mask. The workflow subsequently excluded protected and open-space lands, associated suitable areas with cadastral parcels, normalized and dissolved parcel identifiers using ParcelKey, and a recalculated suitable area from the resulting unique parcel geometries and then applied a minimum requirement of 1 ha of cumulative suitable area per retained parcel. The final baseline inventory contained 3497 normalized unique cadastral parcels encompassing 16,366.49 ha of GIS-identified suitable area, with suitable land representing an average of 42.46% of total parcel area. Peri-urban contexts accounted for the largest share of the final suitable area, containing 2497 parcels and 73.16% of the total, compared with 476 urban and 524 rural parcels. Sensitivity analysis indicated strong stability under alternative weighting schemes, with spatial overlap exceeding 99% relative to the baseline. Reducing the suitability-score threshold from 3.0 to 2.5 produced only minor changes, whereas increasing it to 3.5 reduced the inventory to 3095 parcels and 13,712.89 ha. From a sustainability perspective, the framework provides a spatial decision-support approach for coordinating renewable-energy planning with agricultural land stewardship, conservation constraints, and more efficient use of already fragmented land resources. By making the effects of exclusions, parcel thresholds, and analytical assumptions explicit, the approach supports more transparent and reproducible evaluation of land-use trade-offs relevant to sustainable development. The resulting inventory is intended as a first-stage planning resource rather than a determination of project feasibility or site-level sustainability performance. Full article

Hard and brittle material components with complex curved surfaces are widely used in critical foundational parts within aerospace, optoelectronics, and other fields. Their machining quality directly determines the performance and reliability of high-end equipment. However, the inherent properties of hard and brittle materials make them prone to surface/subsurface damage during traditional polishing processes, and maintaining the form accuracy of complex curved surfaces is challenging. Although abrasive waterjet polishing enables non-contact flexible processing, its energy efficiency is low. Additionally, although ultrasonic-assisted polishing can improve material removal, its spatial localization is insufficient, limiting energy utilization efficiency. To address these issues, this paper proposes a novel method of focused, ultrasonic, vibration-assisted abrasive waterjet polishing. The influence of the radiation force and cavitation force of the focused ultrasonic field on abrasive particle motion is analyzed, and analytical equations for abrasive particle velocity are established. Subsequently, single-factor and response surface methodologies are employed to systematically evaluate the influence of process parameters on machining quality and efficiency. The material removal process during FUAP involves both plastic shearing/chip formation and localized brittle fracture. Focused ultrasonic assistance promotes micro-cutting and plastic shearing, while localized crushing pits indicate that brittle fracture remains non-negligible. The focused ultrasound superimposes alternating stress onto the impact action, mitigating microscale crushing pit defects during the brittle removal process of monocrystalline silicon. Furthermore, appropriately increasing ultrasonic power, enlarging abrasive particle size, and raising abrasive concentration all contribute to enhanced material removal from monocrystalline silicon. Adjusting the nozzle height to the effective region of the focused ultrasonic energy field promotes material removal via chip formation while avoiding pit defects caused by excessive fracture. These results suggest that focused ultrasonic energy can be effectively integrated into abrasive waterjet polishing to enhance material removal while suppressing brittle surface defects, thereby offering a promising strategy for the ultra-precision finishing of hard and brittle components with complex curved surfaces. Full article

This article reviews the reactive magnetron sputtering of piezoelectric Aluminium Nitride (AlN) thin films, with a focus on process parameter optimisation and system-level deposition challenges. AlN is a leading material for MEMS and RF applications owing to its c-axis (002) orientation, high acoustic velocity, wide bandgap (∼6.2 eV), and CMOS compatibility. We review the influence of sputtering power, nitrogen flow ratio, substrate temperature, and target-to-substrate distance on crystallographic quality and document practical hardware challenges, including vacuum leakage, grounding faults, target erosion, and mass flow controller drift, that critically affect reproducibility but are systematically underreported in the literature. A perspective is provided on emerging application domains where optimised AlN films address current performance gaps, including next-generation RF/telecom systems towards 6G and Future Networks, harsh environment sensing and actuation, biomedical ultrasound, and IoT energy harvesting. The complementarity between AlN and Silicon Carbide (SiC) is discussed for high-temperature, high-power, and radiation-hard MEMS, where AlN/SiC heterostructures combine the piezoelectric activity of AlN with the mechanical and chemical robustness of SiC. It also incorporates a discussion of dopant- and heteroepitaxy-based AlN engineering, AlN deposition on a wider range of substrates, the role of seed and electrode underlayers, and pulsed-DC sputtering as a third power supply mode alongside RF and conventional DC. Full article

Single-event burnout (SEB) remains a persistent threat to SiC power MOSFETs in space, yet rapid evaluation of SEB susceptibility without costly heavy-ion campaigns is challenging. This work demonstrates that femtosecond laser two-photon absorption (TPA) can fill that role for a commercial 1200 V SiC MOSFET—provided the laser energy is correctly mapped to heavy-ion linear energy transfer (LET). We derive an equivalent LET model that incorporates the thermal spike effect, giving LET_eq = Γ₁E₀² + Γ₂E₀⁴, which corrects the classical square law at high excitation intensities where it fails. Three ionization-driven failure signatures emerge: drain-to-gate and drain-to-source single-event leakage current (SELC), and SEB. The SEB threshold saturates near 500 V once LET exceeds 25 MeV·cm²/mg—roughly 42% of the device’s 1200 V rating. From these thresholds, we define a safe operating area: below 200 V is safe, 200–600 V risks SELC degradation, and above 600 V carries high SEB risk. Benchmarking against published heavy-ion data shows SEB threshold agreement within 15%, and within 5% at high LET. We stress that the TPA method captures ionization-driven effects only; it does not replicate displacement damage. These results support rapid, laser-based screening of SiC power devices for radiation hardness. Full article

Perovskite solar cells (PSCs) have emerged as a disruptive photovoltaic technology for aerospace and extreme environment applications, driven by their substantial power-to-weight ratio and mechanical flexibility. However, continuous operation under harsh conditions, characterized by the AM0 spectrum, deep vacuum, extreme thermal cycling, and ionizing radiation, exposes the fundamental thermodynamic instability of traditional organic–inorganic hybrid perovskites. This comprehensive review systematically synthesizes 131 recent studies to provide a holistic framework for designing ultrastable, radiation-hardened PSCs. We critically examine the underlying degradation mechanisms, including vacuum-induced volatile desorption, UV-triggered halide segregation, and thermomechanical fracture at buried interfaces. To overcome these critical barriers, we highlight advanced engineering strategies: the transition to all-inorganic CsPbX₃ and lead-free double/chalcogenide perovskites (e.g., Cs₂SnI₆, CaHfS₃), the implementation of dopant-free inorganic transport layers coupled with self-assembled monolayers (SAMs) for cascade band alignment, and the integration of polymeric scaffolds for fracture energy toughening. Furthermore, we emphasize the imperative shift toward solvent-free vacuum deposition techniques (ALD, PLD). A distinctive focus of this review is the integration of Artificial Intelligence; specifically, we evaluate Deep Learning architectures, such as Long Short-Term Memory (LSTM) networks, for predictive State of Health (SOH) monitoring, underscoring the vital transition from simulated to empirical datasets. Finally, coupled with Material Flow Cost Accounting (MFCA), this review outlines a strategic roadmap for the commercialization and deployment of autonomous, self-diagnosing photovoltaic platforms in next-generation satellite and deep-space missions. Full article

Infrared small target detection (ISTD) remains challenging in complex cluttered environments because targets usually occupy only a few pixels and exhibit weak thermal radiation with limited texture information. The problem becomes more severe in high-resolution infrared imaging systems, where sliding-window inference is commonly adopted under memory and computational constraints. However, the truncated field of view may lead to contextual information loss and increased false alarms in cluttered regions. To address these issues, we propose the Selective Contextual Uplift and Attention Network (SCUA-Net). The proposed network adopts a U-Net++-style densely nested encoder–decoder architecture to enhance multi-scale feature interaction and preserve fine-grained weak-target features. In addition, a Global-Context Calibration Coordinate Attention (GCC-CA) module is introduced to inject window-level contextual statistics into coordinate attention, thereby improving clutter suppression and localization robustness under sliding-window inference. During training, a joint optimization strategy combining Online Hard Example Mining (OHEM) and Dice Loss is employed to alleviate severe foreground–background imbalance. During inference, Gaussian-weighted fusion is adopted to reduce stitching artifacts between adjacent windows. Experimental results on NUDT-SIRST and IRSTD-1k validate the effectiveness of the proposed method. SCUA-Net achieves 99.15% Pd, 0.558 × 10⁻⁶ Fa, and 0.9570 IoU on NUDT-SIRST, while maintaining competitive performance on IRSTD-1k at 161.6 FPS on an NVIDIA RTX 4090 platform, demonstrating favorable accuracy, robustness, and real-time performance in complex infrared scenarios. Full article

Background: Accelerated bone healing in patients with traumatic brain injury (TBI) is well documented in long bone fractures but remains poorly studied in mandibular fractures. This study compared mandibular fracture healing rates in patients with and without TBI using high-frequency ultrasonography. Methods: A prospective comparative study was conducted from June 2020 to November 2021 at a single tertiary care center. All patients with mandibular fractures were enrolled in the study. They were divided into two groups as Group 1—with TBI—and Group 2—without TBI. All patients underwent either open reduction and internal fixation or intermaxillary fixation. Fracture healing was assessed weekly for four weeks using high-frequency ultrasonography (6–15 MHz) to evaluate callus formation patterns. Results: A total of 77 patients were enrolled in the study, of which 22 were in Group 1 and 55 in Group 2. Groups were comparable for age (33.23 ± 13.48 vs. 35.80 ± 13.65 years, p = 0.391) and gender distribution (p = 0.977). Mean time to initial callus formation was significantly shorter in Group 1 (15.45 ± 1.96 days) compared to Group 2 (19.98 ± 3.04 days, p < 0.001). By the second week, soft callus was evident in 27.3% of TBI patients versus 9.1% without TBI (p = 0.007). By the fourth week, 72.7% of Group 1 showed hard callus formation compared to 27.3% in Group 2 (p < 0.001). Glasgow Coma Scale scores showed significant inverse correlation with callus formation timing (p < 0.001). Conclusions: Mandibular fractures demonstrate accelerated healing in patients with TBI, with callus formation occurring approximately 4.5 days earlier. Ultrasonography provides an effective, radiation-free method for serial fracture assessment. These findings may inform surgical timing and follow-up protocols in polytrauma patients. Full article

This study presents an archaeometric characterization of fifteen blue-and-white Chinese porcelain sherds (17^th–19^th centuries) from the Jingdezhen, Anxi, and Dehua kiln systems, compared with fragments recovered from the Santana Convent (Lisbon), particularly eighteenth-century materials. A combination of non-invasive, minimally invasive and micro-destructive techniques, including Ground-State Diffuse Reflectance Spectroscopy (GSDR), X-ray Photoelectron Spectroscopy (XPS), micro-Raman spectroscopy, X-ray Fluorescence (XRF), X-ray diffraction (XRD), and stereomicroscopy, was employed to investigate cobalt pigments, glaze composition, firing conditions, and provenance indicators. The results reveal systematic differences between dark- and light-blue glazes, reflecting distinct pigment-processing technologies or simple concentration effects inducing different cobalt coordination environments and/or oxidation states. Raman spectroscopy confirms that cobalt occurs mainly as Co²⁺ ions dissolved in the amorphous silicate glaze matrix. No Raman-detectable crystalline cobalt silicate or cobalt aluminate phases were identified. XRF and XPS analyses show elevated Mn/Co and Fe/Co ratios combined with extremely low arsenic contents, suggesting the predominant use of domestic Chinese cobalt sources. XRD analyses identified quartz, mullite, and minor anorthite, consistent with traditional high-fired hard-paste porcelain technology. Dark-blue radiating star-shaped colored radiating features, particularlyfrequent in Dehua porcelains, were also identified in selected Santana Convent samples, suggesting their attribution to Dehua kiln production and demonstrating the value of glaze defects as complementary provenance markers. Full article

Amid rapid urbanization and the expansion of higher education campuses, the physical and psychological well-being of college students has garnered increasing scientific attention. Although outdoor activities are crucial for student health, participation rates are heavily constrained by outdoor thermal comfort (OTC). This study investigates the OTC of university students in Xi’an, China, utilizing the Universal Thermal Climate Index (UTCI) to assess thermal perceptions across four distinct open spaces and to propose localized bioclimatic design interventions. The results reveal four key findings: (1) The meteorological correlates of thermal sensation vary significantly by spatial typology; relative humidity (RH) and air temperature (Ta) dominate in sunken spaces (HB), whereas solar radiation (G), globe temperature (Tg), and wind velocity (Va) are the primary correlates in sports squares (CS) and activity squares (SH). (2) Thermal benchmarks exhibit remarkable spatial heterogeneity during summer. The Neutral UTCI (NUTCI) varied widely from 17.11 °C in hard-paved squares (SH) to 26.13 °C in shaded bridge areas (JG), with the corresponding neutral zones (NUTCIR) shifting accordingly. (3) Significant variations in thermal adaptation exist even within identical macro-climates, underscoring the necessity of microclimate-specific design. (4) Targeted bioclimatic strategies—including optimized vegetation deployment, shading structures, localized sprinkler systems, and permeable paving—are proposed. These findings provide actionable guidelines for urban planners and landscape architects to optimize campus environments, thereby encouraging outdoor engagement and enhancing student well-being. Full article

Traumatic brain injury (TBI), mainly caused by road traffic accidents, is a serious global public health concern. Computed tomography (CT) is the best way to detect intracranial haemorrhage (ICH), but it is not always feasible because it is hard to access, exposes people to radiation, and is expensive, especially in low- and middle-income countries. Portable near-infrared spectroscopy (NIRS) devices offer a non-invasive, point-of-care option for early detection of ICH. The objectives of this study were to estimate the cost per case detected for patients with mild-to-moderate TBI, to estimate incremental cost and to perform a budget impact analysis to assess the financial feasibility of implementing this technology. This study employed a decision tree model from a health system perspective to calculate the cost per detected case and the incremental cost of NIRS across three tiers of care: ambulances, community health centres (CHCs), and tertiary hospitals. The cost per mild-to-moderate TBI case found was Rs. 2177.90 in ambulances, Rs. 748.09 in CHCs, and Rs. 628.14 in tertiary hospitals. The extra cost per patient was Rs. 984.15, Rs. 360.90, and Rs. 289.78, respectively. At the system level, NIRS raised the total costs for 264 ambulance patients from Rs. 37.71 lakh to Rs. 40.31 lakh and for 858 CHC patients from Rs. 115.64 lakh to Rs. 118.73 lakh. National extrapolation indicates a first-year budgetary impact of approximately Rs. 442 crores for ambulances and Rs. 187 crores for CHCs. These results support the strategic, phased implementation of NIRS to use resources better and improve early diagnosis of TBI. Full article

Extragalactic background light (EBL), formed by the light radiated and re-radiated by stars, galaxies, and active galactic nuclei throughout the evolution of the Universe, brings the imprint of the history of the rate of the formation of emitting astrophysical objects and the Universe’s expansion. It makes EBL one of the fundamental quantities in cosmology. The optical depth for high-energy emission from the distant active galactic nuclei provides a constraint for the EBL density that is clear from the foreground galactic and other emissions, and, therefore, for the cosmological parameters. In this work, we investigate the high-redshift active galaxy 4C +55.17 (z = 0.902), whose unusually hard and stable high-energy spectrum makes it a valuable probe of EBL-induced absorption effects. Using observations extending from GeV to TeV energies, we reconstruct the optical depth associated with gamma-ray propagation and compare the inferred attenuation with predictions from existing EBL models. The results favor relatively low EBL intensities in the optical and infrared bands, consistent with low-level EBL models and suggesting reduced star formation activity and dust contributions over cosmic evolution. We further explore the cosmological implications of the reconstructed optical depth and derive constraints on the Hubble constant in the range $H_0\approx$ 64–74 km s⁻¹ Mpc⁻¹, with an average value of $H_0=69\pm 4$ km s⁻¹ Mpc⁻¹. These findings demonstrate the potential of hard-spectrum, high-redshift gamma-ray sources such as 4C +55.17 as cosmological probes for studying EBL evolution and addressing current tensions in cosmological parameter measurements. Full article

Silicon photomultipliers (SiPMs) have become widely used as photodetectors in high-energy physics, nuclear physics, medical imaging, and space applications. In many of these fields, SiPMs are required to operate in high-radiation environments, which are notoriously problematic for silicon sensors. For this reason, it is essential to study the changes in their performance characteristics after exposure to radiation. In this study, a number of SiPM samples were exposed to non-uniform radiation at the CHARM facility at CERN. Half of the samples were operated above breakdown during the test, while others remained off. Intermittent measurements allowed for tracking the changes in I-V curves and signal shapes during the irradiation itself. The focus was on detecting differences in irradiation damage between the operational and non-operational SiPM samples. The I-V curves and signal shapes in both cases for three different types of SiPM are presented, and a comparison is made. Full article

To realise high-speed free-space optical communication links in harsh space environments, it is crucial to consider the link’s operating wavelength, the performance of the optical receiver, and the radiation hardness of the avalanche photodiode (APD)—optical detectors in the optical receivers. In this work, we experimentally evaluated the radiation hardness of 2.5 Gb/s receivers based on InGaAs/AlGaAsSb APDs integrated with Ommic CGY2102UH/C2 transimpedance amplifiers. Proton energy (62 MeV) and fluence (up to 3.8 × 10¹⁰ p/cm²) representative of space environments were used to irradiate multiple receivers, ensuring rigour. After irradiation, the receivers maintained their avalanche gain and photocurrent, while exhibiting bandwidths exceeding 1.5 GHz. Despite a slight increase in APD’s dark current at high reverse bias, there was no degradation of the receiver’s bit error rate. At 2.5 Gb/s data rate and 1550 nm wavelength, the irradiated receivers achieved a bit error rate of 10⁻⁹ with an average optical power of −38.2 dBm, outperforming selected commercial receivers by ~3 dB. Since the displacement damage dose induced by the proton radiation levels used in this work are representative of those in Low Earth, Geostationary and Global Positioning System orbits, we demonstrated that InGaAs/AlGaAsSb APDs have sufficient radiation hardness to be employed as optical detectors of high-speed optical links in harsh space environments. Full article