A new enhanced PSPICE implementation of the equivalent circuit model of SiPM detectors

The present work proposes an improved PSPICE implementation of the equivalent electrical model of silicon photomultipliers (SiPMs) to simulate and predict their transient re-sponse to avalanche trigger events. In particular, the developed model provides a detailed investigation of magnitude and timing of the read-out signals and can therefore be exploited to perform reliable circuit-level simulations. The modeling approach used is strictly related to the physics of each basic microcell constituting the SiPM device, and allows the avalanche timing as well as the photodiode current and voltage to be accurately simulated. Predictive capabilities of the proposed model are demonstrated by means of experimental measurements on a real detector. Versatility of the proposed model is also confirmed

A Low Jitter and Low Power Electronic Interface for Time-of-Flight Positron Emission Tomography Silicon Photomultiplier Detectors

A time-of-flight (TOF) detection system for a silicon photomultiplier (SiPM) is designed for the purpose of improving on existing technology for applications in positron emission tomography, with an emphasis on low power and low timing jitter. A reconstruction algorithm is implemented in Matlab to demonstrate the effect of TOF on the image quality per number of source events, as compared to systems restricted to line-of-response (LOR) data only. A case study is performed on SiPM functionality, behavioral modeling, and contemporary front-end amplification designs for a SiPM detector. A charge sensitive amplifier (CSA) circuit is modified for simultaneous collection of timing and energy information, implementing a novel hybrid current-division scheme by capacitively coupling the SiPM to the CSA so that the SiPM\u27s fast leading edge behavior and linear energy-charge correlation is preserved, while conserving power and minimizing jitter. Simulations provide the proof of concept for this design, operating at under 600 μW of power, and injecting less than 60 ps of jitter into the timing output signal. Preliminary testing is conducted using a specialized integrated circuit with analog input CSA channels to verify operation. An energy resolution of 11.7 % was achieved for the 511 keV peak of a Na-22 source, and 10.9 % for the 662 keV peak of a Cs-137 source, using an ON Semiconductor 3mm SiPM and a LYSO scintillator. Advisors: Sina Balkir and Michael Hoffma

Characterization of Silicon Photomultiplier and Design of Front-End Electronics for ALOFT

ALOFT is an aircraft campaign led by Birkeland Centre for Space Science at University of Bergen. The primary goal of the campaign is to look for Terrestrial Gamma Ray Flashes and gamma-ray glows, both high-energetic phenomena associated with thunderstorms. Among the several instruments to be used in the campaign is the UIB-BGO instrument, which will be upgraded with two new gamma-ray detectors. The new gamma-ray detectors will consist of two LYSO-scintillators of different sizes coupled to Silicon Photomultipliers. This thesis contributes to these detectors by characterizing the Silicon Photomultipliers and designing front-end electronics for the Silicon Photomultiplier, appropriate for the application. The signal shape, height, and length from the Silicon Photomultiplier are verified through measurement. Additionally, they are used to conclude with the best configuration of the Silicon Photomultiplier, with timing in mind. Other important characteristics are calculated, such as temperature sensitivity and linearity. The signal shape of Silicon Photomultiplier coupled to the LYSO-scintillator is also verified. A design of front-end electronics for the Silicon Photomultiplier is made; the challenge here was the large and fast signal from the Silicon Photomultiplier and its large detector capacitance. A solution of preamplifiers has been designed to resolve this. And a design of the shaping circuit is made; this reduces noise but still retains the fast signal. The needed parameters of the front-end electronics are calculated and verified through simulation. The specific components to be used are verified in simulations; additionally, the preamplifier is physically tested with Silicon Photomultiplier input.Masteroppgave i fysikkPHYS399MAMN-PHY

Study of fast radiation-detectors based on fast halide scintillator crystals and their application to the CERN n_TOF experiment

The inorganic scintillator detectors are widely used in nuclear experiments. New advances on the development of such detectors make it necessary a continuous review of new materials and photosensors. In this work, four fast scintillator crystals based on halide materiaIs: a 18x18x25 mm3 CeBr3, a 18x18x25 mm3 Csl(Na) and two CeF3 of, respectively, 18x18x40 mm3 and 18x18x50 mm3, coupled to fast photomultiplier tubes, R7600U-200 and a PIN diode, have been characterised using both spectroscopic and pulse shape analysis techniques. A specific electronics associated, a preamplifier and a shaper, have been developed. These radiation detectors have been characterised in the n_TOF facility at CERN by the prompt gamma-rays emitted from neutron-capture reactions {n, gamma) for the isotopes 197Au and natAg, proving so the ability of these fast detectors to work in a such background. The prompt gammas from the 235U{n,f) reaction were detected in coincidence with gaseous detectors, the PPAC chambers, for neutron kinetic energies ranging from a few eV to several keV. Furthermore, the g-flash arriving to the nTOF experimental areas produced by the CERN-PS pulsed proton beam when impinging in the nTOF spallation target, was studied at both EAR-1 and EAR-2, after passed by the neutron-beam pipes of, respectively, 200 m flight path in horizontal and 20m flight path in vertical

Topical Workshop on Electronics for Particle Physics

The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities

Photonic low-cost sensors for in-line fluid monitoring. Design methodology

779 p.The paradigm of process monitoring has evolved in the last years, driven by a clear need for improving efficiency, quality and safety of processes and products. Sectors as manufacturing, energy, food and beverages, etc. are fostering the adoption of innovative methods for controlling their processes and products, in a non-destructive, in-place, reliable, fast, accurate and cost-efficient manner. Furthermore, the parameters requested by the industry for the quality assessment are evolving from basic magnitudes as pressures, temperatures, humidity, etc. to complete chemical and physical fingerprints of these products and processes. In this situation, techniques based on the UV/VIS/NIR light-matter interaction appear to be optimum candidates to face the request of the industry. Moreover, at this moment, when we are witnessing a technological revolution in the field of optoelectronic components, which are required for setting up these light-based analyzers.However, being able to integrate these optoelectronic components with the rest of subsystems (electronics, optics, mechanics, hydraulics, data processing, etc.) is not straightforward. The development of these multi-domain and heterogeneous sensor products meeting not just technological but also market objectives poses a considerable technical and organizational challenge for any company.In this context, a methodological hybrid and agile integration of photonic components within the rest of subsystems towards a sensor product development is presented as the main outcome of the thesis. The methodology has been validated in several industrial scenarios, being three of them included in this thesis, which covers from hydraulic fluid quality control to real-time monitoring of alcoholic beverage fermentation process

GSI Scientific Report 2016

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Automatic supervision of Pv systems and degradation analysis of thin film PV modules

Monitoring and regular performance analysis of Grid-Connected Photovoltaic (GCPV) systems are of primal importance in order to ensure an optimal energy harvesting and reliable power production at competitive costs. Main faults in GCPV systems are caused by short-circuits or open-circuits in PV modules, inverter disconnections, PV module degradation and the presence of shadows on the PV array plane. Detecting these faults can minimize generated losses by reducing the time in which the PV system is working below its optimum point of power generation. In addition, the degradation of Tin Film PV (TFPV) modules under outdoor exposure is still not fully understood and is currently object of research. A better understanding on this topic would be important for selecting the best PV technology for the appropriate climatic condition and for improving the reliability and performance of PV systems. Simulations play a crucial role in both outdoor behaviour forecasting and automatic fault detection of GCPV systems. Two PV module/array models have been used in the present thesis in order to simulate the outputs of GCPV systems of different topologies and solar cell technologies, as well as in the fault detection procedure. Moreover, five different algorithms were used for estimating the unknown parameters of both PV models in order to see how these estimated parameters affect their accuracy in reproducing the outdoor behaviour of three GCPV systems. The obtained results show that the metaheuristic algorithms are more efficient than the Levenberg-Marquardt algorithm (LMA) especially in bad weather conditions and both PV models perform well when used in the automatic fault detection procedure. A new approach for automatic supervision and remote fault detection of GCPV systems by means of OPC technology-based monitoring is presented in this thesis. The fault detection procedure used for the diagnosis of GCPV systems is based on the analysis of the current and voltage indicators evaluated also from monitored data and expected values of current and voltage obtained from the model of the PV generator. Three GCPV systems having different sizes, topologies and cell technologies have been used for the experimental validation of the proposed fault detection method. The analysis of current and voltage indicators has demonstrated effectiveness in the detection of most probable faults occurred in the PV arrays in real time. Furthermore, obtained results show that the combination of OPC monitoring along with the proposed fault detection procedure is a robust tool which can be very useful in the field of remote supervision and diagnosis of GCPV systems. Finally, the study of degradation issues of TFPV modules corresponding to four technologies: a-Si:H, a-Si:H/µc-Si:H, CIS and CdTe, deployed under outdoor conditions for long term exposure is also addressed in the present thesis. The impact of the degradation on the output power of the PV modules is analysed, in order to determine their annual degradation rate and their stabilization period. The degradation rate is obtained through a procedure based on the evolution of the module effective peak power over time. The stabilization period is evaluated by means of two methods: the evolution of DC-output power of the PV module, and the power-irradiance technique. The obtained results show that the CIS PV module is the most stable compared to the other technologies, when deployed under Continental-Mediterranean Climate. The a-Si:H and a-Si:H/µc-Si:H PV modules also perform quite well, showing degradation rates and stabilization periods similar to the expectations. The CdTe module shows poor performances, with the highest degradation rate, and long stabilization period of 32 months. Lastly, the parameter extraction technique has been also applied to analyse the evolution of model parameters for a-Si:H and a-Si:H/µc-Si:H arrays working in outdoor conditions for long term exposure.Los fallos principales en los SFCR son causados por cortocircuitos o circuitos abiertos en módulos fotovoltaicos, desconexiones de inversores, degradación de módulos fotovoltaicos y presencia de sombras en el plano del generador fotovoltaico. La detección de estos fallos puede minimizar las pérdidas generadas al reducir el tiempo en que el sistema fotovoltaico está funcionando por debajo de su punto óptimo de generación de energía. Por otro lado, la degradación de los módulos fotovoltaicos de capa delgada (TFPV) en condiciones reales de trabajo sigue siendo actualmente objeto de investigación. Una mejor comprensión de este tema es importante para seleccionar la tecnología fotovoltaica más adecuada para cada condición climática específica y mejorar así tanto la fiabilidad como el rendimiento de los sistemas fotovoltaicos. Las simulaciones desempeñan un papel crucial tanto en el pronóstico del comportamiento real como en la detección automática de fallos en los SFCR. En la presente tesis se han utilizado dos modelos de módulos fotovoltaicos para simular las salidas de los sistemas de diferentes topologías y tecnologías de células solares, así como en el procedimiento de detección de fallos. Se han utilizado cinco algoritmos diferentes para estimar los parámetros de ambos modelos con el fin de ver cómo estos parámetros afectan a su precisión en la reproducción del comportamiento real de tres SFCR. Los resultados obtenidos muestran que los algoritmos meta-heurísticos son más eficientes que el algoritmo de Levenberg-Marquardt (LMA) especialmente en malas condiciones climáticas, aunque ambos modelos pueden ser utilizados para la supervisión y la detección automática de fallos. En esta tesis se presenta un nuevo enfoque para la supervisión automática y la detección remota de fallos en SFCR mediante la monitorización basada en la tecnología OPC. El procedimiento de detección de fallos utilizado para el diagnóstico de SFCR se basa en el análisis de los indicadores de corriente y tensión evaluados también a partir de datos monitorizados y valores esperados de corriente y tensión obtenidos a partir del modelo del generador fotovoltaico. Se han utilizado tres SFCR de diferentes tamaños, topologías y tecnologías fotovoltaicas para la validación experimental del método de detección de fallos propuesto. El análisis de los indicadores de corriente y tensión ha demostrado efectividad en la detección de los fallos más probables en generadores fotovoltaicos en tiempo real. Además, los resultados obtenidos muestran que la combinación de monitorización OPC junto con el procedimiento de detección de fallos propuesto es una herramienta robusta que puede ser muy útil en el campo de la supervisión remota y el diagnóstico de SFCR. Finalmente, en la presente tesis se aborda el estudio de los problemas de degradación de módulos fotovoltaicos de capa delgada correspondientes a cuatro tecnologías: a-Si:H, a-Si:H/µc-Si:H, CIS y CdTe, en condiciones de trabajo a la intemperie durante periodos prolongados de exposición. Se analiza el impacto de la degradación en la potencia de salida de los módulos fotovoltaicos para determinar su tasa de degradación anual y su período de estabilización. Los resultados obtenidos muestran que el módulo fotovoltaico CIS es el más estable comparado con las otras tecnologías, cuando trabajan en condiciones de clima continental mediterráneo. Los módulos fotovoltaicos a-Si:H y a-Si:H/µc-Si:H también presentan un buen comportamiento, mostrando tasas de degradación y períodos de estabilización similares a los esperados. El módulo de CdTe muestra las peores prestaciones, con una mayor tasa de degradación y un largo período de estabilización de 32 meses. Por último, se ha aplicado también la técnica de extracción de parámetros para analizar la evolución de los parámetros del modelo para generadores fotovoltaicos de módulos de a-Si: H y a-Si:H/µc-Si:H en condiciones reales de trabajo durante largos periodos de tiempo