Grzegorz Jablonski

Mixed-Mode Simulation and Analysis of Digital Single Event Transients in Fast CMOSICs

Single event transient (SET) pulses produced from heavy ion irradiation in digital integrated circuits (ICs) are modeled and analyzed using a mixed-mode approach, that is, three-dimensional (3-D) semiconductor device simulation coupled with a circuit solver. In this paper, we analyze the factors affecting the generation and propagation of digital SET pulses in fast CMOS ICs. Our mixed-mode simulations of various ion strike locations allowed to obtain agreement with measured data and explain the earlier published wide distribution of SET pulse widths created by heavy ion radiation in digital CMOS ICs at a given linear energy transfer (LET) value, which was observed experimentally, but not fully understood. We also indicate that the transient charge-collection current pulse (width and shape) on the struck device node is not directly related to the SET voltage pulse that will propagate through a logic circuit, and therefore current pulses alone should not be treated as a measure of DSET.

Interfaces and communication protocols in ATCA-based LLRF control systems

Linear accelerators driving Free Electron Lasers (FELs), such as the Free Electron Laser in Hamburg (FLASH) or the X-ray Free Electron Laser (XFEL), require sophisticated Low Level Radio Frequency (LLRF) control systems. The controller of the LLRF system should stabilize the phase and amplitude of the field in accelerating modules below 0.02% of the amplitude and 0.01 degree for phase tolerances to produce an ultra stable electron beam that meets the required conditions for Self-Amplified Spontaneous Emission (SASE). Since the LLRF system for the XFEL must be in operation for the next 20 years, it should be reliable, reproducible and upgradeable. Having in mind all requirements of the LLRF control system, the Advanced Telecommunications Computing Architecture (ATCA) has been chosen to build a prototype of the LLRF system for the FLASH accelerator that is able to supervise 32 cavities of one RF station. The LLRF controller takes advantage of features offered by the ATCA standard. The LLRF system consists of a few ATCA carrier blades, Rear Transition Modules (RTM) and several Advanced Mezzanine Cards (AMCs) that provide all necessary digital and analog hardware components. The distributed hardware of the LLRF system requires a number of communication links that should provide different latencies, bandwidths and protocols. The paper presents the general view of the ATC A-based LLRF system, discusses requirements and proposes an application for various interfaces and protocols in the distributed LLRF control system.

Behavioral Approach to SiC MPS Diode Electrothermal Model Generation

A comprehensive approach to generation of electrothermal models of silicon carbide (SiC) power Schottky diodes is presented. Both the electrical and thermal parts of the model are behavioral. The electrical one was developed in order to accurately represent the nonlinear properties of SiC merged PiN Schottky (MPS) diodes. Its parameters are automatically obtained with a dedicated numerical procedure. The thermal model derivation differs from the earlier approaches because it is based on the analysis of thermal constant spectrum of the temperature response of a modeled device. Simple model generation and parameter extraction procedures are proposed in which no knowledge of technological data is necessary.

Improvement Of PFC Boost Converter Energy Performance Using Silicon Carbide Diode

This paper discusses the possible benefits of the application of silicon carbide devices in power electronic circuits. The theoretical considerations are illustrated with the measurement results of a 500 W power factor correction (PFC) boost converter. The energy performance of the original converter has been improved owing to the application of silicon carbide Schottky barrier diode (SBD). As expected from the theory, the SiC boost diode allowed the decrease of power losses, thus improving converter efficiency. The ultimate measure of the converter energy performance used by the authors throughout this paper was the product of the energy efficiency and the power factor

Prototype real-time ATCA-based LLRF control system

The linear accelerators employed to drive Free Electron Lasers (FELs), such as the X-ray Free Electron Laser (XFEL) currently being built in Hamburg, require sophisticated control systems. The Low Level Radio Frequency (LLRF) control system should stabilize the phase and amplitude of the electromagnetic fields in accelerating modules with tolerances below 0.02% for amplitude and 0.01 degree for phase to produce ultra-stable electron beam that meets the conditions required for Self-Amplified Spontaneous Emission (SASE). The LLRF control system of a 32-cavity accelerating module of the XFEL accelerator requires acquisition of more than 100 analogue signals sampled with frequency around 100 MHz. Data processing in a real-time loop should complete within a few hundred nanoseconds. Moreover, the LLRF control system should be reliable, upgradeable and serviceable. The Advanced Telecommunications Computing Architecture (ATCA) standard, developed for telecommunication applications, can fulfil all of these requirements. The paper presents the architecture of a prototype LLRF control system developed for the XFEL accelerator. The control system composed of ATCA carrier boards with Rear Transition Modules (RTM) is able to supervise 32 cavities. The crucial submodules, like DAQ, Vector Modulator or Timing Module, are designed according to the AMC specification. The paper discusses results of the LLRF control system tests that were performed at the FLASH accelerator (DESY, Hamburg) during machine studies.

The automatic implementation of Software Implemented Hardware Fault Tolerance algorithms as a radiation-induced soft errors mitigation technique

The radiation-induced soft errors significantly increase the failure rate for advanced electronic components and systems. Rad-sensitive microprocessor-based devices working in the radiation environment are one of the most sensitive parts of the machine. This paper is focusing mainly on the strict software mitigation technique, called Software Implemented Hardware Fault Tolerance (SIHFT). SIHFT methods are based on the redundancy of variables or procedures implemented in compiled project. Sophisticated algorithms are used to check the correctness of control flow in the application. Several articles describe in details theoretical information about software protection algorithms but problem of efficient and error-proof implementation of these methods has always been omitted. Unfortunately, manual implementation of presented algorithms is difficult and can introduce additional problems with program functionality caused by human errors. Presented solution is based on the automatic implementation of SIHFT algorithms during the compilation process. Several modifications of software methods were proposed to make theoretical algorithms possible to the automatic installation.

Integral Interface - Universal Communication Interface for FPGA-Based Projects

During the development process it is very important to assure reliable communication between individual parts of the system. In a special case, when the system is implemented in the FPGA chip, possible solution of communication problem encompass not only ready-made solutions but also especially designed interfaces adapted to specific projects. This paper highlights Integral Interface -universal communication interface for applications in FPGA chip. In addition, presented paper describes specialized program that automatically generates VHDL source code for an interface and supplementary components.

High-performance image acquisition and processing system with MTCA.4

Fast evolution of high-performance cameras in recent years has made them promising tools for observing transient and fast events in large-scale scientific experiments. Complex experiments, such as ITER, take advantage of high-performance imaging system consisting of several fast cameras working in the range of visible and infrared light. The paper presents a first implementation of complete image acquisition system built on the basis of MTCA.4 architecture, which is dedicated for operation with high-resolution fast cameras equipped with Camera Link interface. Image data from the camera are received by the frame grabber card and transmitted to the host via PCIe interface. The modular structure of MTCA.4 architecture allows connecting several cameras to a single MTCA chassis. The system supports precise synchronization with the time reference using Precision Time Protocol (IEEE 1588). The software support for the system includes low-level drivers and API libraries for all components and high-level EPICS-based environment for system control and monitoring.

ATCA-based control system for compensation of superconducting cavities detuning using piezoelectric actuators

The linear particle accelerators use superconducting cavities working with high operating gradients. The electromagnetic wave, transferred to the cavity as a set of successive pulses, causes mechanical stresses inside the cavity. Therefore, the resonance frequency of the cavity is significantly modulated, which may lead to cavity detuning in range of hundreds of Hz. The piezoelectric actuators are commonly used for the compensation of the cavity detuning. The paper presents the prototype piezo control system which is capable of compensating 32 cavities simultaneously. Moreover, the first tests of the system in FLASH (Free-Electron Laser in Hamburg) accelerator are presented. The described system is ready to be applied to the next version of LLRF (Low Level Radio Frequency) control system based on ATCA (Advanced Telecommunications Computing Architecture) architecture.

Behavioural Electro-Thermal Modelling of SiC Merged PiN Schottky Diodes

This paper presents a new accurate behavioural static model of SiC Merged PiN Schottky (MPS) diode. This model is dedicated to static and quasi-static electro-thermal simulations of MPS diodes for industrial applications. The model parameters were extracted using the Weighted Least Square (WLS) method for a few selected commercially available SiC MPS diodes. Additionally, the PSPICE Analogue Behavioural Model (ABM) model implementation is also given. The relevance of the model has been statistically proven. The thermal behaviour of the devices was taken into account using the lumped Cauer canonical networks extracted from electro-thermal measurements.