A low-cost embedded system for high-energy radiation detection applications was developed for national security proposes, mainly to detect nuclear material and send the detection event to the cloud in real time with tracking capabilities. The proof of concept was built with state-of-the-art electronics such as an adequate Si-based photodetector, a trans-impedance amplifier, an ARM Cortex M4 microcontroller with sufficient ADC capture capabilities, an ESP8266 Internet of Things (IoT) module, an optimized Message Queuing Telemetry Transport (MQTT) protocol, a MySQL data base, and a Python handler program. The system is able to detect alfa particles and send the nuclear detection events to the CloudMQTT servers. Moreover, the detection message records the date and time of the ionization event for the tracking application, and due to a particular MQTT-optimized protocol the message is sent with low latency. Furthermore, the designed system was validated with a standard radiation instrumentation preamplifier 109A system from ORTEC company, and more than one node was demonstrated with an internet connection employing a 20,000 bits/s CloudMQTT plan. Therefore, the design can be escalated to produce a robust big data multisensor network.

The main aim of this paper is to propose a robust fault-tolerant control for a three degree of freedom (DOF) mechanical crane by using a convex quasi-Linear Parameter Varying (qLPV) approach for modeling the crane and a passive fault-tolerant scheme. The control objective is to minimize the load oscillations while the desired path is tracked. The convex qLPV model is obtained by considering the nonlinear sector approach, which can represent exactly the nonlinear system under the bounded nonlinear terms. To improve the system safety, tolerance to partial actuator faults is considered. Performance requirements of the tracking control system are specified in an ${\mathcal{H}}_{\infty }$ criteria that guarantees robustness against measurement noise, and partial faults. As a result, a set of Linear Matrix Inequalities is derived to compute the controller gains. Numerical experiments on a realistic 3 DOF crane model confirm the applicability of the control scheme.

In this work, an AlGaN-based Deep-Ultraviolet Light-Emitting Diode structure has been designed and simulated for the zincblende and wurtzite approaches, where the polarization effect is included. DFT analysis was performed to determine the band gap direct-to-indirect cross-point limit, AlN carrier mobility, and activation energies for p-type dopants. The multiple quantum wells analysis describes the emission in the deep-ultraviolet range without exceeding the direct-to-indirect bandgap cross-point limit of around 77% of Al content. Moreover, the quantum-confined Stark effect on wavefunctions overlapping has been studied, where Al-graded quantum wells reduce it. Both zincblende and wurtzite have improved electrical and optical characteristics by including a thin AlGaN with low Al content. Mg and Be acceptor activation energies have been calculated at 260 meV and 380 meV for Be and Mg acceptor energy, respectively. The device series resistance has been decreased by using Be instead of Mg as the p-type dopant from 3 kΩ to 0.7 kΩ.

This study provides a comprehensive structural, chemical, and optical characterization of CZTS thin films deposited on flexible Kapton substrates via the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The investigation explored the effects of varying deposition cycles (40, 60, 70, and 80) and annealing treatments on the films. An X-ray diffraction (XRD) analysis demonstrated enhanced crystallinity and phase purity, particularly in films deposited with 70 cycles. These films exhibited a notable reduction in secondary phases in the as-deposited state, with further improvements observed after annealing at 400 °C and 450 °C in a sulfur atmosphere. A pole figure analysis indicates a decrease in texture disorder with annealing, suggesting improved crystalline orientation at higher temperatures. Field emission scanning electron microscopy (FE-SEM) showed enhancements in surface morphology, with increased grain size and uniformity post-annealing. Chemical uniformity was confirmed through Secondary Ion Mass Spectrometry (SIMS), Energy-Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). XPS revealed the presence of CZTS phases alongside oxidized phases. Annealing effectively reduced secondary phases, such as ZnO, SnO₂, CuO, and SO₂, enhancing the CZTS phase. An optical analysis demonstrated that annealing at 200 °C in an air atmosphere reduced the band gap from 1.53 eV to 1.38 eV. In contrast, annealing at 400 °C and 450 °C in a sulfur atmosphere increased the band gap to 1.59 eV and 1.63 eV, respectively. The films exhibited p-type conductivity, as inferred from a valence band structure analysis. Density Functional Theory (DFT) calculations provided insights into the observed band gap variations, further substantiating the findings.

In this work, it is presented a unified model to integrate a radiation detector on a single chip using TFTs-based amplifiers, to fabricate a low-cost thermal neutron detector system. The model is based on the current-voltage experimental measurements of the CdS/CdTe detector and CMOS Si-Poly TFTs technology. Parameters obtained by I-V and C-V analysis were introduced into Smart SPICE to design the amplifiers. The output voltage was simulated for a neutron capture event. Three amplification topologies were studied, obtaining an output voltage in the range of 180 to 260 mV with a generated photocurrent pulse around 3.5 lA, which is high enough to be interfaced with a microcontroller. The neutron detector is integrated into TFT amplifiers with a gain of around 50 dB and bandwidth of 4.7 MHz at -3 dB.

In this work, we present the characterization of a UV-sensitive material based on Ga₂O₃-GaOOH, which was obtained through the thermal oxidation of GaAs wafers in ambient air to achieve Ga₂O₃. The material’s oxidation mechanism was thoroughly examined using structural, compositional, and optical approaches. X-ray diffraction analysis identified the presence of the β-Ga₂O₃ crystalline phase, with both in-plane and out-of-plane preferred orientations, along with crystalline inclusions attributed to GaOOH. Furthermore, energy-dispersive spectroscopy confirmed the uniform sublimation of Arsenic, as evidenced by elemental mapping, while Fourier-transform infrared spectroscopy suggested the inclusion of −OH bonds. Surface analysis was carried out by field emission scanning electron microscopy and atomic force microscopy, revealing a grain size of approximately 20 nm. Finally, UV-Vis characterization unveiled a bandgap ranging from 2.9 to 3.9 eV, indicative of the material’s potential for UV-sensitive applications. Overall, the results demonstrate the consistency and reliability of the oxidation process, providing valuable insights into the properties of the Ga₂O₃-GaOOH material for potential technological advancements.