Digital signal processing for segmented HPGe detectors preprocessingalgorithms and pulse shape analysis

MINIBALL is an versatile spectrometer consisting of 24 longitudinally six-fold segmented HPGe detectors, build for the efficient detection of rare γ decays in nuclear reactions of radioactive ion beams. MINIBALL was the first spectrometer equipped with digital electronics. Pulse shape analysis algorithms to determine the interaction position of γ -rays were implemented on a Digital Signal Processor and validated in an experiment using a collimated γ -ray source. Emphasis was placed on the properties of the different digital signal processing algorithms, the consequences for the implementation and the applicability for position determination. The next generation of γ -ray spectrometers will consist of highly segmented HPGe detectors equipped with digital electronics, resulting in a more than ten-fold increase in complexity compared to current spectrometers. To enable the construction of a γ -ray tracking spectrometer, new and powerful digital electronics will be developed. Preprocessing algorithms, giving the γ -ray energy and generating event triggers, were implemented on a VME module equipped with fast A/D converters and tested with different detectors and sources. Emphasis was placed on the detailed simulation and understanding of the algorithms as well as the influence of electronics and detector onto the energy resolution

Intelligent Reconfigurable Integrated Satellite Processor

We present our Intelligent Reconfigurable Integrated Satellite (IRIS) Processor. At the heart of the system are our reconfigurable vision chips which are capable of massively parallel analog processing. The smart vision chips are capable of not only centroiding and pattern recognition but also tracking and controlling devices including MEMs devices and active pixel arrays. In addition to discussing the active optic and active electronic devices, several small satellite system applications are presented along with experimental and simulation results

A scalable packetised radio astronomy imager

Includes bibliographical referencesModern radio astronomy telescopes the world over require digital back-ends. The complexity of these systems depends on many site-specific factors, including the number of antennas, beams and frequency channels and the bandwidth to be processed. With the increasing popularity for ever larger interferometric arrays, the processing requirements for these back-ends have increased significantly. While the techniques for building these back-ends are well understood, every installation typically still takes many years to develop as the instruments use highly specialised, custom hardware in order to cope with the demanding engineering requirements. Modern technology has enabled reprogrammable FPGA-based processing boards, together with packet-based switching techniques, to perform all the digital signal processing requirements of a modern radio telescope array. The various instruments used by radio telescopes are functionally very different, but the component operations remain remarkably similar and many share core functionalities. Generic processing platforms are thus able to share signal processing libraries and can acquire different personalities to perform different functions simply by reprogramming them and rerouting the data appropriately. Furthermore, Ethernet-based packet-switched networks are highly flexible and scalable, enabling the same instrument design to be scaled to larger installations simply by adding additional processing nodes and larger network switches. The ability of a packetised network to transfer data to arbitrary processing nodes, along with these nodes' reconfigurability, allows for unrestrained partitioning of designs and resource allocation. This thesis describes the design and construction of the first working radio astronomy imaging instrument hosted on Ethernet-interconnected re- programmable FPGA hardware. I attempt to establish an optimal packetised architecture for the most popular instruments with particular attention to the core array functions of correlation and beamforming. Emphasis is placed on requirements for South Africa's MeerKAT array. A demonstration system is constructed and deployed on the KAT-7 array, MeerKAT's prototype. This research promises reduced instrument development time, lower costs, improved reliability and closer collaboration between telescope design teams

System dynamics approach to user independence in high speed AFM

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 135-146).As progress in molecular biology and nanotechnology continues, demand for rapid and high quality image acquisition has increased to the point where the limitations of atomic force microscopes (AFM) become impediments to further discovery. Many biological processes of interest occur on time scales faster than the observation capability of conventional AFMs, which are typically limited to imaging rates on the order of minutes. Imaging at faster scan rates excite resonances in the mechanical scanner that can distort the image, thereby preventing higher speed imaging. Although traditional robust feedforward controllers and input shaping have proven effective at minimizing the influence of scanner distortions, the lack of direct measurement and use of model-based controllers has required disassembling the microscope to access lateral motion with external sensors in order to perform a full system identification experiment, which places excessive demands on routine microscope operators. This work represents a new way to characterize the lateral scanner dynamics without addition of lateral sensors, and shape the commanded input signals in such a way that disturbing dynamics are not excited in an automatic and user-independent manner. Scanner coupling between the lateral and out-of-plane directions is exploited and used to build a minimal model of the scanner that is also sufficient to describe the source of the disturbances. This model informs the design of an online input shaper used to suppress components of the high speed command signals. The method presented is distinct from alternate approaches in that neither an information-complete system identification experiment, nor microscope modification are required. This approach has enabled an increase in the scan rates of unmodified commercial AFMs from 1-4 lines/second to over 100 lines/second and has been successfully applied to a custom-built high speed AFM, unlocking scan rates of over 1,600 lines/second. Images from this high speed AFM have been taken at more than 10 frames/second. Additionally, bulky optical components for sensing cantilever deflection and low bandwidth actuators constrain the AFM's potential observations, and the increasing instrument complexity requires operators skilled in optical alignment and controller tuning. Recent progress in MEMS fabrication has allowed the development of a new type of AFM cantilever with an integrated sensor and actuator. Such a fully instrumented cantilever enables direct measurement and actuation of the cantilever motion and interaction with the sample, eliminating the need for microscope operators to align the bulky optical components. This technology is expected to not only allow for high speed imaging but also the miniaturization of AFMs and expand their use to new experimental environments. Based on the complexity of these integrated MEMS devices, a thorough understanding of their behavior and a specialized controls approach is needed to guide non-expert users in their operation and extract high performance. The intrinsic properties of such MEMS cantilevers are investigated, and a combined approach is developed for sensing and control, optimized for high speed detection and actuation.by Daniel J. Burns.Ph.D

Advanced techniques for diagnostics and control applied to particle accelerators

201 p.Esta tesis versa en torno a tecnologías y técnicas novedosas orientadas al diagnóstico y control para aceleradores de partículas. Se centra principalmente en el desarrollo de dos aplicaciones para dicho propósito; un monitor de posición de haz (beam position monitor o BPM en inglés) por un lado, y un control de RF denominado sistema de RF de bajo nivel (low-level RF o LLRF en inglés) por el otro. Además, se han desarrollado completos bancos de pruebas, permitiendo de esta manera el testeo de las mencionadas soluciones en el laboratorio. El estudio de técnicas de muestreo y procesamiento digital para su posterior implementación también juega un papel importante en este trabajo.De esta manera, las principales contribuciones de esta tesis son el desarrollo de un BPM y un sistema de control LLRF altamente flexibles y reconfigurables, estando ambos basados en hardware digital. Las soluciones presentadas han sido diseñadas con el objetivo de crear herramientas especialmente adecuadas para labores de investigación en laboratorio. Las aplicaciones obtenidas cumplen este objetivo, mostrando características especialmente valiosas como una rápida etapa de prototipado y alta modularidad.Otra línea de la presente tesis está dirigida al estudio de técnicas avanzadas de muestreo y procesamiento digital de señal, las cuales son posteriormente implementadas en las citadas aplicaciones. Finalmente, la última parte de este trabajo trata sobre la integración de la información producida por estas herramientas de diagnóstico y control en EPICS, un sistema de control ampliamente utilizado en el campo de los aceleradores de partículas

書き換え可能なゲートアレイを用いた無作為抽出法に基づく実時間画像処理に関する研究

長崎大学学位論文 学位記番号:博(工)甲第53号 学位授与年月日:平成30年3月20日Nagasaki University (長崎大学)課程博

自己投影法に基づく高速三次元形状検査の研究

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora