A digital ring transverse feedback low-level RF control system

The Coordinate Rotation Digital Computer (CORDIC) algorithm has emerged as a pivotal method for executing trigonometric and various mathematical operations within digital systems. Field-Programmable Gate Arrays (FPGAs) have witnessed a remarkable surge in adoption for implementing the CORDIC algorithm owing to their inherent flexibility and exceptional performance capabilities. This paper endeavours to provide a comprehensive overview of FPGA implementations of the CORDIC algorithm, elucidating both the advantages and challenges associated with this methodology. It thoroughly examines various FPGA architectures customized for CORDIC implementation, meticulously analyzing their respective trade-offs regarding resource utilization, performance metrics, and accuracy levels. Moreover, the paper explores numerous applications where the FPGA-based CORDIC algorithm shines, illustrating its adaptability across diverse domains like digital signal processing and control systems. These applications underscore the algorithm's efficacy in addressing real-world challenges and its potential to significantly augment system performance and efficiency.By furnishing profound insights into FPGA-based CORDIC implementations, this paper serves as an invaluable resource for engineers and researchers keen on harnessing the capabilities of FPGAs for high-performance mathematical computations in digital systems.

Digital Systems Design with FPGAs and CPLDs

This paper is a summary of a collective work in the framework of the Working Party in International Nuclear Data Evaluation and Co‐operation (WPEC) to investigate the reasons for systematic reactivity underprediction of thermal LEU‐LWR (Low‐Enriched Uranium, Light‐Water Reactor). This keff underprediction (≈ −500 pcm) is observed with the most recent nuclear data libraries (ENDF/B‐VI.8, JENDL3.3 and JEFF3.0) This report reviews the evaluation work performed at several laboratories [Oak Ridge National Laboratory (ORNL), Los Alamos National Laboratory (LANL), Commissariat a l’énergie atomique de Bruyeres‐Le‐Chatel (CEA‐BRC), International Atomic Energy Agency (IAEA)] as well as the integral tests (mainly at LANL, Knoll Atomic Power Laboratory (KAPL), Bettis Atomic Power Laboratory (BAPL), Nuclear Research and Consultancy Group NRG‐Petten, CEA and IAEA) of the successive versions of the new evaluated files. The present status of the work can be summarized as follows:• Improved evaluations of 238U inelastic data proposed by LANL and CEA‐BRC were tested against integral benchmarks and partially improve the reactivity prediction.• The thermal capture cross‐section of 238U has been revised, and a new evaluation of 238U resonance parameters, up to 20 keV, is in progress at ORNL. Integral tests have ensured that the modifications of 238U capture cross‐section in the thermal and resolved range were still compatible with 238U integral measurements (238U capture rate ratios measured in critical facilities and 239Pu build‐up prediction in a depleted pressurized water reactor (PWR) assembly).It is demonstrated that the combination of the new inelastic data (LANL or BRC) with the preliminary ORNL resonance parameter set gives a good correction of the reactivity under‐estimation. The provisional conclusions of this collective work are expected to contribute toward the improvement of the future versions of nuclear data libraries.

The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

Digital systems are pervasive in modern society. We use computers for bookkeeping, engineering, publishing, and entertainment. Digital communications systems handle our telephone calls and enable our Web browsing sessions. Other uses of digital systems are less visible. Most consumer electronics products are largely digital and becoming more so. Music today is distributed digitally on compact optical disks, and video production is rapidly becoming a digital process. A typical appliance is controlled digitally by a microcomputer. As many as ten microcomputers can be found in the average car for controlling functions ranging from the sound system to the antilock brakes.

The NRC recognizes that a more complete technical basis for understanding and regulating advanced digital technologies in commercial nuclear power plants is needed. A concern is that the introduction of digital safety systems may have an impact on risk. There is currently no standard methodology for measuring digital system reliability. A tool currently used to evaluate NPP risk in analog systems is the probabilistic risk assessment (PRA). The use of this tool to evaluate the digital system risk was considered to be a potential methodology for determining the risk. To test this hypothesis, it was decided to perform a limited PRA on a single dominant accident sequence. However, a review of existing human reliability analysis (HRA) methods showed that they were inadequate to analyze systems utilizing digital technology. A four step process was used to adapt existing HRA methodologies to digital environments and to develop new techniques. The HRA methods were then used to analyze an NPP that had undergone a backfit to digital technology in order to determine, as a first step, whether the methods were effective. The very small-break loss of coolant accident sequence was analyzed to determine whether the upgrade to the Eagle-21 process protection system had an effect on risk. The analysis of the very small-break LOCA documented in the Sequoyah PRA was used as the basis of the analysis. The analysis of the results of the HRA showed that the mean human error probabilities for the Eagle-21 PPS were slightly less than those for the analog system it replaced. One important observation from the analysis is that the operators have increased confidence steming from the better level of control provided by the digital system. The analysis of the PRA results, which included the human error component and the Eagle-21 PPS, disclosed that the reactor protection system had a higher failure rate than the analog system, although the difference was not statistically significant.

The effectiveness of digital solutions is largely unproven as there are very few published data in real-world outbreak settings. Modelling studies provide low-certainty evidence of a reduction in secondary cases if digital contact tracing is used together with other public health measures such as self-isolation. Cohort studies provide very low-certainty evidence that digital contact tracing may produce more reliable counts of contacts and reduce time to complete contact tracing. Digital solutions may have equity implications for at-risk populations with poor internet access and poor access to digital technology. Stronger primary research on the effectiveness of contact tracing technologies is needed, including research into use of digital solutions in conjunction with manual systems, as digital solutions are unlikely to be used alone in real-world settings. Future studies should consider access to and acceptability of digital solutions, and the resultant impact on equity. Studies should also make acceptability and uptake a primary research question, as privacy concerns can prevent uptake and effectiveness of these technologies.

With the development of the nuclear technology, the instrumentation and control (I&C) systems have evolved from the analog systems to the current state-of-the-art digital systems. It has been reported that China has recently developed the digital systems based on Field Programmable Gate Array (FPGA) in CAP1400 nuclear power plant. And the lack of methods in the verification and validation work of the FPGA systems has become an important issue. This thesis describes the basic principles of FPGA, and the development process of FPGA. And then, the thesis proposes an effective improved method—formal verification, describing three methods of formal verification in detail, namely theorem proof, model checking, and equivalence proof. Describing the FPGA verification methodology and pointing out the shortcomings of traditional simulation, comparing the formal verification and traditional simulation verification in terms of complexity, timing, and applications. We also discussed the importance of formal verification method in FPGA. We selected the temperature and power control chip based on FPGA as an example, using System Verilog Assertions (SVA) method of model checking, and verifying the SRAM controller module and the internal calculation module. Through the analysis of the results, this paper proved the feasibility of formal verification methods in the instrumentation and control system of nuclear power plants, and provided some references of verification work for other system chips in instrumentation and control of nuclear power plant in the future work. The thesis showed that verification engineers can use the formal verification method based on SVA to verify the robustness of the system quickly and accurately. This method improves the controllability and observability which are the main drawbacks of the traditional simulation verification. It also avoids several issues in the debug process of traditional simulation verification, improving the accuracy and completeness of the chip verification.

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This document introduces the planned new search for the neutron Electric Dipole Moment at the Spallation Neutron Source at the Oak Ridge National Laboratory. A spin precession measurement is to be carried out using Ultracold neutrons diluted in a superfluid Helium bath at T = 0.5 K, where spin polarized 3He atoms act as detector of the neutron spin polarization. This manuscript describes some of the key aspects of the planned experiment with the contributions from Caltech to the development of the project. Techniques used in the design of magnet coils for Nuclear Magnetic Resonance were adapted to the geometry of the experiment. Described is an initial design approach using a pair of coils tuned to shield outer conductive elements from resistive heat loads, while inducing an oscillating field in the measurement volume. A small prototype was constructed to test the model of the field at room temperature. A large scale test of the high voltage system was carried out in a collaborative effort at the Los Alamos National Laboratory. The application and amplification of high voltage to polished steel electrodes immersed in a superfluid Helium bath was studied, as well as the electrical breakdown properties of the electrodes at low temperatures. A suite of Monte Carlo simulation software tools to model the interaction of neutrons, 3He atoms, and their spins with the experimental magnetic and electric fields was developed and implemented to further the study of expected systematic effects of the measurement, with particular focus on the false Electric Dipole Moment induced by a Geometric Phase akin to Berry’s phase. An analysis framework was developed and implemented using unbinned likelihood to fit the time modulated signal expected from the measurement data. A collaborative Monte Carlo data set was used to test the analysis methods.

This paper presents an investigation of dynamically reconfigurable mixed-signal circuit constructed using a digital control system and the new technology of Field Programmable Analog Arrays (FPAA). A Motorola FPAA described in this paper can be used to build filters for analog signals as well as other kinds of analog applications implemented in switched capacitor technology (S/C-technology). The experimental studies described, take advantage of performance and programmability of the FPAA for filtering of an analog signal. The circuit structure is based on 2 parallel FPAA chips, analog multiplexer and multiplexer's control logic controlled by a digital system such as a PC or a Field Programmable Gate Array (FPGA). Dynamic reconfiguration is used in this system for adaptive filtering, or adaptive processing in general. Modeling and measurements of the transition behavior of the switching process between the 2 FPAA chips and analysis of limitations imposed by hardware imperfections will be presented. The experimental system assembled in this work is an excellent vehicle to learn about intricacies in performance of mixed-signal circuits and is used for verification of theoretical predictions and model validation/modification.

2 - Digital Voice Fundamentals

We often hear that we live in a digital age. This refers to the massive adoption of computer systems within every aspect of our lives from smart phones to automobiles to household appliances. This statement also refers to the transformation that has occurred to our telecommunications infrastructure that now transmits voice, video, and data using 1’s and 0’s. There are a variety of reasons that digital systems have become so prevalent in our lives. In order to understand these reasons, it is good to start with an understanding of what a digital system is and how it compares to its counterpart, the analog system. The goal of this chapter is to provide an understanding of the basic principles of analog and digital systems.

A novel silicon detector configuration for radiation dose measurements in an environment where solar energetic particles are of most concern is described. The dosimeter would also measure the dose from galactic cosmic rays. In the lunar environment a large range in particle flux and ionization density must be measured and converted to dose equivalent. This could be accomplished with a thick (e.g. 2 mm) silicon detector segmented into cubic volume elements voxels followed by a second, thin monolithic silicon detector. The electronics needed to implement this detector concept include analog signal processors (ASIC) and a field programmable gate array (FPGA) for data accumulation and conversion to linear energy transfer (LET) spectra and to dose-equivalent (Sievert). Currently available commercial ASIC's and FPGA's are suitable for implementing the analog and digital systems.

Any digital system on very large scale integrations requires clock distributions. For the realization, a dedicated clock tree or a mesh clock is frequently used. Field programmable gate arrays have numerous general-purpose programmable wires based on switching matrices to connect the outputs and inputs of look-up tables and input/output ports. However, field programmable gate arrays never use numerous general-purpose programmable wires for their clock distributions as well as other very large scale integrations to satisfy with the clock skew margin. Field programmable gate arrays also take the dedicated clock trees although the programmability is not high. Currently, field programmable gate arrays can support multiple dedicated clock routing or multiple clock trees. However the number of clock trees is fixed and limited to a small number. Even if application requires a lot of clock distributions, the clock distribution cannot be supported in current field programmable gate arrays. Therefore, this paper proposes a more flexible clock distribution method using general-purpose programmable wires based on wiring channels and switching matrices. In addition, to solve clock skew increase problem, we have introduced a new flip-flop with a two-phase clock signal. This paper presents the simulation results of the proposed clock distribution method on an originally designed filed programmable gate array. In addition, this paper also presents the experimental results that the proposed clock distribution method can work correctly on a Cyclone V field programmable gate array.