Perez, M., F. Alcalde, M. S. Haro, I. Sidelnik, J. J. Blostein, M. Gomez Berisso, and J. Lipovetzky. "Implementation of an ionizing radiation detector based on a FPGA-controlled COTS CMOS image sensor." In 2017 XVII Workshop on Information Processing and Control (RPIC), 1–6. 2017 XVII Workshop on Information Processing and Control (RPIC)., 2017.
Abstract: This work presents the development and implementation of an ionizing radiation detector based on a commercial off the shelf CMOS image sensor and a FPGA. The response of the system was tested in irradiations with gamma photons, beta and alpha particles using different configurations of the image sensor. Finally, we analyze the possible uses of such configurations in the discrimination of events produced by alpha particles in mixed radiation fields.
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Núñez Regueiro, M., P. Esquinazi, M. A. Izbizky, C. Durán, D. Castello, and J. Luzuriaga. "Tunneling systems in high temperature superconductors." Annales de Physique 13, no. 5 (1988): 401–406.
Abstract: We have measured the thermal conductivity, sound attenuation and relative variation of sound velocity of compounds of the La-Sr-Cu-O and RBa2Cu3O7 families, where R is a rare-earth. We have found that all these properties can be quantitatively correlated within a tunneling system model similar to that used in amorphous materials. This interpretation would naturally explain the anomalous linear term of the low temperature specific heat observed in these materials.
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Hofer, J. A., S. Bengio, and Haberkorn N. "Effect of Gd magnetic impurities on the superconducting properties of highly disordered molybdenum nitride microstrips." Applied Physics A 129, no. 9 (2023): 631.
Abstract: We investigated the impact of Gd magnetic impurities on the superconducting properties of disordered MoNx thin films grown by reactive co-sputtering at room temperature. The samples were fabricated in the two gun cluster using Mo and Gd targets in an Ar + N2 atmosphere with a total pressure of 0.67 Pa and a N2 concentration of 7%. The study focuses in thin films with thickness between 22 and 27 nm. We modified the chemical composition by varying the power of the Gd target from 0 to 24 W, fixing the Mo in 100 W. The chemical state of the samples was analysed using X-ray Photoelectron Spectroscopy. The samples primarily exhibit an amorphous metallic Mo and Gd nitride structure. With the addition of Gd, the superconducting critical temperature is suppressed, dropping from 7.4 K for pure MoNx to below 3 K for samples containing ≈ 4.5 at.% Gd. Furthermore, the temperature dependence of the upper critical field (Hc2) and the vortex dissipation mechanism are also affected. Specifically, Hc2(0) is reduced from 10 to 7.7 T for samples with 3.1 at.% Gd. Moreover, at a temperature of 3 K, there is an increase in the magnetic field dependence of the critical current density for low Gd doping. These alterations also impact the instability of the vortex lattice, limiting the maximum achievable vortex velocity during dissipation.
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Antonio, D., M. I. Dolz, and H. Pastoriza. "Micromechanical magnetometer using an all-silicon nonlinear torsional resonator." Applied Physics Letters 95, no. 13 (2009): 133505–3.
Abstract: In this work, a micromagnetometer employing a nonlinear torsional resonator with a high quality factor Q is presented experimentally. Oscillatory rotation of a conducting plate in the sensed magnetic field H induces eddy currents that dissipate energy. Due to the nonlinear response of the oscillator, the resulting mechanical damping originates frequency shifts in the resonance curve that depend on H. Nonlinearity results from the electrostatic detection, which introduces high order electrical spring constants. The device is fabricated with a standard silicon process and does not incorporate ferromagnetic materials. An analytical nonlinear model that correctly describes the device is also introduced.
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Lederman, D., J. Hasen, I. K. Schuller, E. Osquiguil, and Y. Bruynseraede. "Photoinduced superconductivity and structural changes in high temperature superconducting films." Applied Physics Letters 64, no. 5 (1994): 652–654.
Abstract: The illumination of PryGd1-yBa2Cu 3Ox semiconducting and superconducting thin films increases their critical temperatures and decreases their normal state resistivities if and only if the films are oxygen deficient. Moreover, these changes are enhanced near the Pr-induced metal-insulator transition. Light also causes a contraction of the c-axis in YBa2Cu3Ox which is correlated with the observed photoinduced resistivity changes. These changes are similar to those observed when oxygen-deficient YBa 2Cu3Ox is enriched with oxygen or annealed at room temperature after quenching from high temperatures.
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Fernandes, A., I. Chan, J. Guimpel, O. Nakamura, D. Lederman, and I. Schuller. "Scaling of critical currents in high-temperature superconducting superlattices and thin films." Applied Physics Letters 61, no. 26 (1992): 3181.
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Nakamura, O., J. Guimpel, F. Sharifi, R. Dynes, and I. Schuller. "Synthesis and properties of a-axis and b-axis oriented GdBa2Cu3O7-d high Tc thin films." Applied Physics Letters 61, no. 21 (1992): 2598.
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Nakamura, O., E. Fullerton, J. Guimpel, and I. Schuller. "High Tc thin films with roughness smaller than one unit cell." Applied Physics Letters 60, no. 1 (1992): 120.
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Nakamura, O., I. Chan, J. Guimpel, and I. Schuller. "New buffer layer for high?temperature superconducting ceramics on sapphire: LaBa2Cu3Oy/Ag bilayers." Applied Physics Letters 59, no. 10 (1991): 1245.
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Alcalde Bessia, F., D. Flandre, N. André, J. Irazoqui, M. Pérez, M. Gómez Berisso, and J. Lipovetzky. "Ultra Low Power Ionizing Dose Sensor Based on Complementary Fully Depleted MOS Transistors for Radiotherapy Application." IEEE Transactions on Nuclear Science (2019): 1.
Abstract: We evaluate the use of the thick buried oxide (BOX) of Fully Depleted Silicon-on-Insulator (FD-SOI) transistors for Total Ionizing Dose (TID) measurements in a radiotherapy application. The devices were fabricated with a custom process in UniversitC) Catholique de Louvain (UCL) which allows to make accumulation mode PMOS transistors and inversion mode NMOS transistors. We characterized the temperature behavior of these devices and the response under X-ray radiation produced by an Elekta radiotherapy linear accelerator, and compared the obtained dose sensitivity to other published works. Taking advantage of these devices, an ultra low power MOS ionizing dose sensor, or MOS dosimeter, with inherent temperature compensation is presented. This dosimeter achieved a sensitivity of 154 mV/Gy with a temperature error factor of 13 mGy/°C and a current consumption below 1 nA.
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