16 research outputs found
Analytical model for the ohmic-side interstrip resistance of double-sided silicon microstrip detectors
No full textA compact, analytical model is derived for the n-side interstrip resistance of double-sided silicon microstrip detectors, allowing for fast and accurate prediction of the minimum p-stop (or p-spray) implant dose ensuring adequate interstrip isolation. The basic idea on which the proposed model relies is that the portion of the detector between two adjacent n-strips can effectively be reduced to an equivalent n-channel MOSFET. The interstrip resistance can be evaluated as the output resistance of this equivalent MOSFET using standard SPICE-like models. The influence of radiation-induced oxide charge and p-stop (or p-spray) voltage can be accounted for by simply including, in the threshold voltage expression, the induced flat-band voltage shift and body-effect term, respectively
Time resolving characteristics of HPK and FBK silicon photomultipliers for TOF and PET applications
No full textIn time-of-flight measurements, or positron emission tomography experiments where two gamma rays are detected in coincidence, the time resolution of the photodetector is of primary importance. SiPMs are very promising devices for these applications, since their intrinsic response time can be less than 1 ns. However the actual timing resolution of SiPM is affected by the area (capacitance) of the device, by the type of used to pre-amplify the signal, by the dark count rate which is revealed as pure noise, and other second order effects like cross-talk and after pulsing. In this work we report the characteristics of different samples of Hamamatsu Photonics (HPK) and Fondazione Bruno Kessler (FBK) SiPM, with pixel size ranging from 40 to 100 pm. In particular, we have investigated their time response when stimulated with O(50) ps pulsed laser at wavelengths in the range 400-800 nm. (C) 2009 Published by Elsevier B.V
A fabrication process for silicon microstrip detectors with integrated front-end electronics
No full textWe report on an research and development activity aimed at the fabrication of silicon microstrip detectors with integrated front-end electronics to be used in high-energy physics and space experiments and medical/industrial imaging applications. A specially tailored fabrication technology has been developed at ITC-IRST (Trento, Italy), which allows for the production of single-sided microstrip detectors, with integrated coupling capacitors and polysilicon resistors, as well as active devices, including N-channel junction field effect transistors and N- or P-channel MOS transistors. The main characteristics of the fabrication process are outlined. Experimental results from the electrical characterization of the devices are reported, showing that transistors with good electrical figures can be obtained within the proposed technology while preserving the basic detector parameters
A functionally reconfigurable detector head for scintimammography
No full textA novel prototype detector for scintimammography is presented. The detector is built according to a modular strategy. Each module is
composed of an array of p–i–n diodes, coupled to a CsI(Tl) scintillator and to mixed-mode ASICs with self-triggering, sparsifying, A/D
conversion and bidirectional serial data I/O transfer capabilities. The front-end electronics exhibits good performance in terms of
equivalent input noise charge (ENCo100 e rms). Digital signals are routed out so that each module can be attached to a main board
with an FPGA for overall detector management. PC-based supervision of the detector is accomplished using a LabVIEW graphical user
interface
Evaluation of silicon detectors with integrated JFET for biomedical applications.
No full textThis paper presents initial results from electrical, spectroscopic and ion beam induced charge (IBIC) characterisation of a novel silicon PIN detector, featuring an on-chip n -channel JFET and matched feedback capacitor integrated on its p-side (frontside). This structure reduces electronic noise by minimising stray capacitance and enables highly efficient optical coupling between the detector back-side and scintillator, providing a fill factor of close to 100%. The detector is specifically designed for use in high resolution gamma cameras, where a pixellated scintillator crystal is directly coupled to an array of silicon photodetectors. The on-chip JFET is matched with the photodiode capacitance and forms the input stage of an external charge sensitive preamplifier (CSA). The integrated monolithic feedback capacitor eliminates the need for an external feedback capacitor in the external electronic readout circuit, improving the system performance by eliminating uncontrolled parasitic capacitances. An optimised noise figure of 152 electrons RMS was obtained with a shaping time of 2 mus and a total detector capacitance of 2 pF. The energy resolution obtained at room temperature (2°C) at 27 keV (direct interaction of I-125 gamma rays) was 5.09%, measured at full width at half maximum (FWHM). The effectiveness of the guard ring in minimising the detector leakage current and its influence on the total charge collection volume is clearly demonstrated by the IBIC images. © 2009, Institute of Electrical and Electronics Engineers (IEEE
Feasibility studies of microelectrode silicon detectors with integrated electronics
No full textWe describe our experience on design and fabrication, on high-resistivity silicon substrates, of microstrip detectors and integrated electronics, devoted to high-energy physics experiments and medical/industrial imaging applications, We report on the full program of our collaboration, with particular regards to the tuning of a new fabrication process, allowing for the production of good quality transistors, while keeping under control the basic detector parameters, such as leakage current. Experimental results on JFET and bipolar transistors are presented, and a microstrip detector with an integrated JFET in source-follower configuration is introduced. (C) 2002 Elsevier Science B.V. All rights reserved
Design and characterization of integrated front-end transistors in a micro-strip detector technology
No full textWe present the developments in a research program aimed at the realization of silicon micro-strip detectors with front-end electronics integrated in a high resistivity substrate to be used in high-energy physics, space and medical/ industrial imaging applications. We report on the fabrication process developed at IRST (Trento, Italy), the characterization of the basic wafer parameters and measurements of the relevant working characteristics of the integrated transistors and related test structures
Processing and first characterization of detectors made with high resistivity n- and p-type Czochralski silicon
No full textWe report on the design, manufacturing and first characterisation of pad diodes, test structures and microstrip detectors processed with high resistivity magnetic Czochralski (MCz) p- and n-type Si. The pre-irradiation study on newly processed microstrip detectors and test structures show a good overall quality of the processed wafers. After irradiation with 24 GeV/c protons up to 4 x 10(14) cm(-2) the characterisation of n-on-p and p-on-n MCz Si sensors with the C-V method show a decrease of the full depletion voltage and no space charge sign inversion. Microscopic characterisation has been performed to study the role of thermal donors in Czochralski Si. No evidence of thermal donor activation was observed in n-type MCz Si detectors if contact sintering was performed at a temperature lower than 380 degrees C and the final passivation oxide was omitted. (c) 2005 Published by Elsevier B.V
Fabrication of microstrip detectors and integrated electronics on high resistivity silicon
No full textA fabrication technology has been developed at ITC-irst (Trento, Italy) for the realisation of silicon microstrip detectors with integrated front-end electronics, to be used in high-energy physics and space experiments as well as in medical/industrial imaging applications. The main technological issues are addressed, and experimental results from the electrical characterisation of the first prototype batch are reported, showing that good quality transistors are obtained within the proposed technology while preserving the basic detector parameters
O sentido e a emoção no conteúdo do motivo da atividade de estudo
No full textIn this article we make a reflection in the form of a bibliographic essay on the content that moves the student to the study activity. Based on the theoretical foundations of Historical-Cultural Psychology, referring to the basic elements of the structure of human activity, by Leontiev and Davídov, we analyzed the place of meaning and emotion in the student\u27s activity. The objective was to identify the relationship of the senses and emotions that arise as a reason content in the study activity. The reflections result from the theoretical readings and experiences of the three author teachers. We consider the study activity (object of analysis) from the perspective of the general structure of the activity. This correlation, we identified the desire, the will and the significance as links that connect the senses and emotions to the reason for the activity, that is, as of this content.Neste artigo, fazemos uma reflexão na forma de ensaio bibliográfico sobre o conteúdo que move o estudante à atividade de estudo. Com base nos fundamentos teóricos da Psicologia Histórico-Cultural, referente aos elementos básicos da estrutura da atividade humana, por Leontiev e Davídov, analisamos o lugar do sentido e da emoção na atividade do estudante. O objetivo foi identificar relações dos sentidos e das emoções que surgem como conteúdo do motivo na atividade de estudo. As reflexões resultam das leituras teóricas e das vivências dos três professores autores. Consideramos a atividade de estudo (objeto de análise) pelo viés da estrutura geral da atividade. Dessa correlação, identificamos o desejo, a vontade e a significação como nexos que ligam os sentidos e as emoções ao motivo da atividade, ou seja, como conteúdo deste
