42 research outputs found
Recommended from our members
Wide bandgap semiconductor radiation detectors for extreme environments
Get PDFWide bandgap semiconductor photodiodes were investigated for their suitability as radiation detectors for high temperature applications (≥ 20 °C), through measurements, calculations of key parameters of the devices, and relating the results back to the material, geometry of the detectors, environment under which the detectors were investigated, and previously published work. Three families of photodiodes were examined.
4H-SiC vertical Schottky UV photodiodes with Ni2Si interdigitated contacts were characterised for their response under dark and UV illumination. Electrical characterisation up to 120 °C and room temperature responsivity measurements (210 nm to 380 nm) suggested that the devices could operate at low UV light intensities, even at high visible and IR backgrounds without the use of filters, and at high temperatures.
4H-SiC Schottky photodiode detector arrays with planar thin NiSi contacts were investigated for X-ray (≤ 35 keV) detection and photon counting spectroscopy at 33 °C. The electrical characterisation of the devices up to 140 °C and subsequent analysis suggested that the devices are likely to operate as high temperature X-ray spectrometers.
Results characterising GaAs p+-i-n+ mesa photodiode detectors for their room temperature visible and near infrared responsivity (580 nm to 870 nm), as well as their high temperature (≤ 60 °C) X-ray detection performance (at 5.9 keV) are presented. GaAs p+-i-n+ mesa photodiodes were also shown to be suitable for β- particle (electron) spectroscopy and X-ray fluorescence spectroscopy (≤ 21 keV) at 33 °C.
The X-ray and electron spectroscopic measurements were supported by a comprehensive treatment of the noise components in charge sensitive preamplifiers. Calculations showed the potential benefits of using a SiC, rather than Si, JFET as the input transistor of such a preamplifier operating at high temperatures. The spectroscopic measurements, using both the 4H-SiC and GaAs photodiodes, are presented along with noise analysis to detangle the different noise components present in the reported spectrometers, identify the dominant source of noise, and suggest potential improvements for future spectrometers using the reported devices
Disseny microelectrnic de circuits discriminadors de polsos pel detector LHCb
Get PDFThe aim of this thesis is to present a solution for implementing the front end system of the Scintillator Pad Detector (SPD) of the calorimeter system of the LHCb experiment that will start in 2008 at the Large Hadron Collider (LHC) at CERN. The requirements of this specific system are discussed and an integrated solution is presented, both at system and circuit level. We also report some methodological achievements. In first place, a method to study the PSRR (and any transfer function) in fully differential circuits taking into account the effect of parameter mismatch is proposed. Concerning noise analysis, a method to study time variant circuits in the frequency domain is presented and justified. This would open the possibility to study the effect of 1/f noise in time variants circuits. In addition, it will be shown that the architecture developed for this system is a general solution for front ends in high luminosity experiments that must be operated with no dead time and must be robust against ballistic deficit
Analog Readout for the ATLAS Semiconductor Tracker
Get PDFThe context of the work, described in this document, is the development of electroniccomponents for future high-energy physics experiments.The first part deals with design and evaluation of an electronic device for reading and processingthe signals, created by charged elementary particles in solid state detectors. This device has to workwithin an experimental environment, which imposes very rigorous requirements in terms of signalprocessing speed, noise performance, power dissipation, radiation hardness and size as well as interms of system complexity. These constraints force its realization as a VLSI integrated circuit. Anemphasis is put on the major problem, which occurs when dealing with extremely small signals, as theones produced by a semiconductor detector..
Comparison of the measured X-ray yields of kaonic helium-3 and helium-4
Get PDFKaonisches Helium ist ein exotisches Atom,†‬welches sich besonders zur Untersuchung der starken Wechselwirkung bei niedrigen Energien eignet.†‬Die starke Wechselwirkung zwischen Kaon und Heliumkern verursacht eine Verschiebung der inneren Energieniveaus des Atoms,†‬die mithilfe spektroskopischer Methoden messbar ist.†In den letzten Jahren wurden ‬verstärkt im Zuge zweier Experimente†(‬E570†‬in Japan und SIDDHARTA in Italienâ€), ‬die Verschiebung des 2p Niveaus in kaonischem Helium-3†‬und Helium-4 - ĂĽber die Messung der RöntgenĂĽbergänge - ‬bestimmt.†‬Ein weiteres Experiment†(‬E17â€) ‬ist fĂĽr†‬2012†‬an J-PARC,†‬Japan,†‬geplant,†‬in welchem mögliche Unterschiede zwischen der Verschiebung in kaonischem Helium-3†‬und in kaonischem Helium-4†‬festgestellt werden sollen.†FĂĽr das Experiment E17†‬werden neuartige,†‬hochmoderne Siliziumdetektoren,†‬sogenannte†‬Silicon Drift Detektoren ‬verwendet,†‬deren Funktionsparameter fĂĽr diese Messungen optimiert worden sind.†‬Die Anforderungen des experimentellen Aufbaus von†‬E17†‬erfordern zudem eine genaue Kenntnis der Detektoreigenschaften,†‬die im Zuge dieser Doktorarbeit untersucht wurden.†‬HierfĂĽr wurde die Temperaturabhängigkeit ihrer Energie-†‬und Zeitauflösung in einem ähnlichen experimentellen Aufbau an†‬der Forschungsanlage†‬KEK in Japan studiert und mit Modellen ĂĽber die Elektroneneigenschaften in Silizium verglichen.†Des Weiteren wurden†‬in dieser Arbeit†‬die Ăśbergangsraten der RöntgenĂĽbergänge zum ‬2p Niveau in gasförmigem Helium bestimmt.†‬Dazu wurden die Daten des SIDDHARTA Experiments ausgewertet,†‬das mithilfe eines komplexen†‬SDD-Detektorsystems, die RöntgenĂĽbergänge in kaonischem Helium-3†‬und Helium-4†‬gemessen hat.†‬Die absoluten Ăśbergangsraten wurden mit†‬Hilfe einer Monte-Carlo Simulation†‬ermittelt.†‬Da alle bisherigen Experimente flĂĽssiges Helium fĂĽr die Untersuchung der RöntgenĂĽbergänge verwendet haben, konnte mit diesen Ergebnissen†‬erstmals eine Dichteabhängigkeit der Ăśbergangsraten experimentell beobachtet werden,†‬die†- ‬besonders fĂĽr theoretische Berechnungen - wichtige Informationen†‬liefern.†‬Ferner können damit die zu erwarteten Detektionsraten fĂĽr E17,†‬und damit die benötigte Messzeit, abgeschätzt werden.Kaonic helium is an exotic atom where a Kaon replaces a shell electron,†‬well suited for the study of the strong interaction at low energies.†‬The strong interaction between the kaon and the nucleus affects the†‬low-lying atomic states in the kaonic helium atom by causing a shift compared to its†‬electromagnetic value.†‬This shift can be measured with spectroscopic tools,†‬which was performed†recently by two experiments.†‬In particular, the SIDDHARTA experiment at LNF†(‬Italy)†‬investigated the strong interaction shift via the measurement of the X-ray transitions to the†‬2p level in kaonic helium-3†‬and kaonic helium-4.†‬The E17†‬experiment at J-PARC†(‬Japanâ€)‬,†‬planned for†‬2012,†‬measures a possible difference between the shifts in kaonic helium-3†‬and helium-4.†‬For this purpose,†so-called†“‬silicon drift detectorsâ€â€ť ‬are used which have been optimized for the requirements of the experiment.†‬Due to geometrical limits of the E17†‬setup,†‬the properties of these detectors have been investigated in a similar setup.†‬Their energy and time resolutions†‬have been studied as a function of the detector temperature and compared to theoretical models of the electron mobility in silicon.†Furthermore,†‬the yields†(‬i.e.†‬the transition ratesâ€) ‬of the kaonic helium X-ray transitions to the†‬2p level were determined within this thesis.†‬Therefore,†‬the†‬SIDDHARTA data†‬were analysed,†‬where the X-ray transitions in gaseous kaonic helium-3†‬and helium-4†‬were measured with a complex†‬SDD†‬detector system.†‬The absolute yields were obtained with inputs from a Monte Carlo simulation.†‬Since the previous measurements on the kaonic helium X-ray transitions solely used liquid kaonic helium,†‬these results give crucial information on theoretical calculations of the density dependence of the yields.†‬Additionally,†‬the determination of the yields in gaseous kaonic helium-3†‬and helium-4†‬allows an estimation of the prospective X-ray detection efficiencies in E17
Developments toward a Silicon Strip Tracker for the PANDA Experiment
Get PDFThe PANDA detector at the future FAIR facility in Darmstadt will be a key experiment in the understanding of the strong interaction at medium energies where perturbative models fail to describe the quark-quark interaction. An important feature of the detector system is the ability to reconstruct secondary decay vertices of short-lived intermediate states by means of a powerful particle tracking system with the the Micro-Vertex Detector (MVD) as central element to perform high-resolution charmonium and open-charm spectroscopy. The MVD is conceived with pixel detectors in the inner parts and double-sided silicon strip detectors at the outer half in a very lightweight design. The PANDA detector system shall be operated in a self-triggering broadband acquisition mode. Implications on the read-out electronics and the construction of the front-end assemblies are analyzed and evaluation of prototype DSSD-detectors wrt. signal-to-noise ratio, noise figures, charge sharing behavior, spacial resolution and radiation degradation discussed. Methods of electrical sensor characterization with different measurement setups are investigated which may be useful for future large-scale QA procedures. A novel algorithm for recovering multiple degenerate cluster hit patterns of double-sided strip sensors is introduced and a possible architecture of a Module Data Concentrator ASIC (MDC) aggregating multiple front-end data streams conceived. A first integrative concept for the construction and assembly of DSSD modules for the barrel part of the MVD is introduced as a conclusion of the thesis. Furthermore, a detailed description of a simplified procedure for the calculation of displacement damage in compound materials is given as reference which was found useful for the retrieval of non-ionizing energy loss for materials other than silicon.Der PANDA Detektor im zukünftigen FAIR-Beschleunigerkomplex in Darmstadt wird ein Schlüsselexperiment im Verständnis der starken Wechselwirkung bei mittleren Energien, bei denen kein Zugang über perturbative Methoden zur Quark-Quark Interaktion existiert, sein. Eine wichtige Eigenschaft des Detektorsystems, die Ortsrekonstruktion sekundärer Zerfallsvertizes kurzlebiger Zwischenzustände, wird dabei durch ein Spurverfolgungssystem mit dem Mikro-Vertex Detektor (MVD) als wichtigstem Element zur hochauflösenden Charmoniumund Open-Charm Spektroskopie garantiert. Der MVD ist konzipiert als leichtgewichtiges, geteiltes Silizium-Detektorsystem mit Pixeldetektoren im inneren Bereich und doppelseitigen Streifendetektoren (DSSD) in den äußeren Regionen. Das PANDA Detektorsystem soll in einem selbstgetriggertem Regime Daten breitbandig und ohne Totzeitverluste verarbeiten können. Die sich daraus ergebenden Implikationen auf den Aufbau der Ausleseelektronik und der Front-end-Baugruppen werden analysiert und es werden Ergebnisse von Messungen an DSSD-Prototypen im Hinblick auf Signal-zu-Rausch-Verhältnis, Rauscheigenschaften, Ladungsteilungsverhalten, Ortsauflösung und Bestrahlungstoleranz diskutiert. Methoden zur elektrischen Charakterisierung von Sensoren werden untersucht, die bei zukünftigen großangelegten QA-Untersuchungen nützlich eingesetzt werden können. Ein neuartiger Cluster- Korrelationsalgorithmus, welcher mehrfach entartete Clusterhit-Muster zu erkennen vermag wird ebenso vorgestellt wie eine mögliche Architektur des noch zu entwickelnden Module-Data- Concentrator ASIC (MDC), welcher die Datenströme der Front-end Chips auf Modulebene zusammenfassen soll. Ein erstes integratives Konzept für Konstruktion und Zusammenbau von DSSD-Modulen des Barrel-Bereichs des MVD wird im Abschluss der Dissertation vorgestellt. Darüber hinaus wird eine detaillierte Beschreibung einer vereinfachten Vorschrift zur Berechnung des Versetzungsschadens durch Neutronen in zusammengesetzten Stoffen angegeben, welche sich als nützlich für die Ableitung des nicht-ionisierenden Energieverlustes in Materialien neben Silizium erwiesen hat
Conference on Charge-Coupled Device Technology and Applications
Get PDFPapers were presented from the conference on charge coupled device technology and applications. The following topics were investigated: data processing; infrared; devices and testing; electron-in, x-ray, radiation; and applications. The emphasis was on the advances of mutual relevance and potential significance both to industry and NASA's current and future requirements in all fields of imaging, signal processing and memory
Low-frequency noise in downscaled silicon transistors: Trends, theory and practice
Get PDFBy the continuing downscaling of sub-micron transistors in the range of few to one deca-nanometers, we focus on the increasing relative level of the low-frequency noise in these devices. Large amount of published data and models are reviewed and summarized, in order to capture the state-of-the-art, and to observe that the 1/area scaling of low-frequency noise holds even for carbon nanotube devices, but the noise becomes too large in order to have fully deterministic devices with area less than 10nm×10nm. The low-frequency noise models are discussed from the point of view that the noise can be both intrinsic and coupled to the charge transport in the devices, which provided a coherent picture, and more interestingly, showed that the models converge each to other, despite the many issues that one can find for the physical origin of each model. Several derivations are made to explain crossovers in noise spectra, variable random telegraph amplitudes, duality between energy and distance of charge traps, behaviors and trends for figures of merit by device downscaling, practical constraints for micropower amplifiers and dependence of phase noise on the harmonics in the oscillation signal, uncertainty and techniques of averaging by noise characterization. We have also shown how the unavoidable statistical variations by fabrication is embedded in the devices as a spatial “frozen noise”, which also follows 1/area scaling law and limits the production yield, from one side, and from other side, the “frozen noise” contributes generically to temporal 1/f noise by randomly probing the embedded variations during device operation, owing to the purely statistical accumulation of variance that follows from cause-consequence principle, and irrespectively of the actual physical process. The accumulation of variance is known as statistics of “innovation variance”, which explains the nearly log-normal distributions in the values for low-frequency noise parameters gathered from different devices, bias and other conditions, thus, the origin of geometric averaging in low-frequency noise characterizations. At present, the many models generally coincide each with other, and what makes the difference, are the values, which, however, scatter prominently in nanodevices. Perhaps, one should make some changes in the approach to the low-frequency noise in electronic devices, to emphasize the “statistics behind the numbers”, because the general physical assumptions in each model always fail at some point by the device downscaling, but irrespectively of that, the statistics works, since the low-frequency noise scales consistently with the 1/area law
Belle II Technical Design Report
Full text linkThe Belle detector at the KEKB electron-positron collider has collected
almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an
upgrade of KEKB is under construction, to increase the luminosity by two orders
of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2
/s luminosity. To exploit the increased luminosity, an upgrade of the Belle
detector has been proposed. A new international collaboration Belle-II, is
being formed. The Technical Design Report presents physics motivation, basic
methods of the accelerator upgrade, as well as key improvements of the
detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
Delay-Line 3D Position Sensitive Radiation Detection
Full text linkHigh-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation’s direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR pulses. The detectors and existing electronics can therefore be used to yield imaging instruments for neutron and gamma-rays, in the case of silicon. For CZT, we would prefer to utilize current sensing to be able to clearly isolate the effects of the various charge-transport non-idealities, the full realization of which awaits the fabrication of the custom-designed TIA chip.Ph.D.Nuclear Engineering & Radiological SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91556/1/mhjeong_1.pd
