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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Alcalde Bessia, F., M. Pérez, M. Sofo Haro, I. Sidelnik, J. J. Blostein, S. Suárez, P. Pérez, M. Gómez Berisso, and J. Lipovetzky. "Displacement Damage in CMOS Image Sensors After Thermal Neutron Irradiation." IEEE Transactions on Nuclear Science 65, no. 11 (2018): 2793–2801.
Abstract: In this paper, CMOS image sensors were exposed to thermal neutrons observing an increase in the dark signal of many pixels. The effect was found to be similar to the damage caused by alpha particles irradiation. Rutherford backscattering spectroscopy (RBS) and SIMNRA simulation were used to confirm that the sensors contain boron in the insulation layers. The damage produced by thermal neutrons is explained as displacement damage caused by alpha particles and lithium-7 ions in the silicon active volume of the sensors after boron-10 thermal neutron capture.
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Galimberti, C. L., F. Alcalde Bessia, M. Perez, M. Gómez Berisso, M. Sofo Haro, I. Sidelnik, J. J. Blostein, H. Asorey, and J. Lipovetzky. "A Low Cost Environmental Ionizing Radiation Detector Based on COTS CMOS Image Sensors." In 2018 IEEE Biennial Congress of Argentina (ARGENCON), 1–6. 2018 IEEE Biennial Congress of Argentina (ARGENCON)., 2018.
Abstract: We present the development of a system for the detection of ionizing radiation based on the Omnivision OV5647 Commercial Off The Shelf image sensor. The data is read and processed in real-time using a Raspberry Pi 3 computer. The amount of charge and geometrical characteristics of the cluster of pixels exited when a particle interacts with the sensor is recorded and used to identify the type of incoming particle, distinguishing between alpha particles and X-ray or gamma photons. The software was programmed in C using the OpenCV library. The system was tested with 137Cs and 241Am radiation sources.
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Lipovetzky, J., A. Cicuttin, M. L. Crespo, M. Sofo Haro, F. Alcalde Bessia, M. Pérez, and M. Gómez Berisso. "Multi-spectral X-ray transmission imaging using a BSI CMOS Image Sensor." Radiation Physics and Chemistry 167 (2020): 108244.
Abstract: In this work we study the performance to obtain X-ray images of a Back Side Illuminated CMOS Image Sensor, the Omnivision OV5647, empoying X-rays from tube with a palladium anode and voltages from 7.5 keV to 50 keV. The performance is compared with the Timepix detector operating in the Time Over Threshold mode. False color images are obtained using data from different energies and brightnesses, to fussion different information on the same picture. The different attenuations are analyzed and discussed in terms of the charge detection efficiency of the CMOS sensor, measured using Fluorescence X-rays and gamma rays from calibrated sources.
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Mateos, H., J. Lipovetzky, F. Alcalde Bessia, M. Perez, P. Cappagli, and M. Gomez Berisso. "Characterization of sensors and design of an embedded photodetectors array for beam profile measurements in radiotherapy." In 2017 Eight Argentine Symposium and Conference on Embedded Systems (CASE), 1–6. 2017 Eight Argentine Symposium and Conference on Embedded Systems (CASE)., 2017.
Abstract: In this work, the dosimetric performance of several Commercial Of The Shelf photodiodes was studied. They were tested against gamma rays from a teletherapy source and were characterized with the aim of building a one-dimensional array of dosimeters able to measure the the spatial distribution of dose in a radiotherapy irradiation field. An embedded system comprising an array of 40 photodiodes and its acquisition electronics was built and tested. The dose resolution of each detector was 0.06 cGy and the spatial resolution of the system 0.5 cm.
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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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