Papers by Keyword: Radiation Detector

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Authors: Antonio Castaldini, Anna Cavallini, Filippo Nava, P.G. Fuochi, P. Vanni
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Authors: Abdou Saouli, Karim Mansour
Abstract: In this work, the study of detector radiations response p-i-n modeling in technology Thin Film on ASIC (TFA) is reported. It has been revealed that for some nanoseconds time formation of preamplifier, the charge induced by the electrons is entirely collected. Nevertheless, a part of the charge created by the holes is integrated, due to the slow transport of this latter, which constitutes a significant limit for detection speeds.
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Authors: Mahmoud A. Hassan
Abstract: CdZnTe , Cadmium zinc telluride (CZT) is an interesting room temperature radiation detector. This research paper is reporting a negative capacitance behavior of CZT detectors at bias voltages around 60V. Initially at 0V, the CZT capacitance is positive and decreases with bias voltage increase. At around 60V, the measured capacitance approaches zero, then with small voltage increase , capacitance value reverses sign and starts to increase in the negative direction with increasing bias voltage . This effect is stable at 100 kHz. The behavior of low and other quality detectors can differ, low quality detectors can show negative capacitance at low bias voltages and low frequencies. The initial explanation of this phenomena is due to non-uniform distribution of impurities inside the bulk material.
399
Authors: João F. Trencher Martins, Robinson A. dos Santos, Fabio E. da Costa, Carlos H. de Mesquita, Margarida M. Hamada
Abstract: The establishment of a technique for mercury iodide (HgI2) purification and crystal growth is described, aiming this crystal future application as room temperature radiation semiconductor detectors. Repeated Physical Vapor Transport (PVT) technique was studied for purification and growth of the crystal. To evaluate the purification efficiency, measurements of the impurity concentration were made after each growth, analyzing the trace impurities. A significant decrease of the impurity concentration, resulting from the purification number, was observed. A significant improvement in the HgI2 radiation detector performance was achieved for purer crystals, growing the crystal twice by the PVT technique.
156
Authors: Giuseppe Bertuccio, Simona Binetti, S. Caccia, R. Casiraghi, Antonio Castaldini, Anna Cavallini, Claudio Lanzieri, Alessia Le Donne, Filippo Nava, Sergio Pizzini, L. Rigutti, G. Verzellesi
Abstract: High performance SiC detectors for ionising radiation have been designed, manufactured and tested. Schottky junctions on low-doped epitaxial 4H-SiC with leakage current densities of few pA/cm2 at room temperature has been realised at this purpose. The epitaxial layer has been characterised at different dose of radiations in order to investigate the SiC radiation hardness. The response of the detectors to alpha and beta particle and to soft X-ray have been measured. High energy resolution and full charge collection efficiency have been successfully demonstrated.
1015
Authors: Bernard F. Phlips, Karl D. Hobart, Francis J. Kub, Robert E. Stahlbush, Mrinal K. Das, Gianluigi De Geronimo, Paul O' Connor
Abstract: We have tested the radiation detection performance of Silicon Carbide (SiC) PIN diodes originally developed as high power diodes. These devices consist of 100 micron thick SiC grown epitaxially on SiC substrates. The size and thickness of the devices make them appropriate for a number of radiation detection applications. We tested 0.25 cm2 and 0.5 cm2 devices and obtained X-ray spectra under illumination with an Am-241 radioactive source. The spectra showed an energy resolution that was consistent with the resolution expected for the large capacitance of the device. Smaller devices with a diameter of 1 mm were also tested and produced spectra with a room temperature energy resolution of ~550 eV, which is consistent with the electronics limit for the capacitance of the small device. We measured the absolute charge generated by X-rays per KeV in SiC by comparing the charge generation with similar silicon devices and determined the energy required per electron hole pair in SiC to be 8.4 eV. We also performed radiation damage tests on these devices and found no significant loss in charge collection up to a photon dose of 100 MRad. Applications for these devices can be found in the fields of particle physics, nuclear physics, nuclear medicine, X-ray fluorescence, X-ray astronomy and X-ray navigation.
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Authors: Giuseppe Bertuccio, S. Caccia, Filippo Nava, Gaetano Foti, Donatella Puglisi, Claudio Lanzieri, S. Lavanga, Giuseppe Abbondanza, Danilo Crippa, F. Preti
Abstract: The design and the experimental results of some prototypes of SiC X-ray detectors are presented. The devices have been manufactured on a 2’’ 4H-SiC wafer with 115 m thick undoped high purity epitaxial layer, which constitutes the detection’s active volume. Pad and pixel detectors based on Ni-Schottky junctions have been tested. The residual doping of the epi-layer was found to be extremely low, 3.7 x 1013 cm-3, allowing to achieve the highest detection efficiency and the lower specific capacitance of the detectors. At +22°C and in operating bias condition, the reverse current densities of the detector’s Schottky junctions have been measured to be between J=0.3 pA/cm2 and J=4 pA/cm2; these values are more than two orders of magnitude lower than those of state of the art silicon detectors. With such low leakage currents, the equivalent electronic noise of SiC pixel detectors is as low as 0.5 electrons r.m.s at room temperature, which represents a new state of the art in the scenario of semiconductor radiation detectors.
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