This article shows a novel approach for Bragg gratings interrogation, based on vertical-cavity surface-emitting laser with high-contrast grating cavity. It is shown that with such a light source, one may achieve simultaneous wavelength sweeping together with output light intensity modulation enabled by a single element. In turn, it allows for designing a two-dimensional (time and wavelength) Bragg grating interrogation scheme. The article consists of analytical deliberations that determine the limiting factors of such an interrogation unit, i.e. interrogation speed and size of the sensing network for given Bragg grating reflectivity, expressed in the form of signal-to-noise ratio. Moreover, an experimental and numerical proof of concept of the sensing unit consisting of fiber Bragg grating sensors with an interrogation speed of 1 kHz and the use of code division multiplexing is also presented.
Soft X-ray (SXR) radiation emitted from tokamak plasmas contains very useful information about plasma stability, shape and impurity content, all key parameters to improve plasma performance. In the deuterium-tritium phase of ITER, the high neutron fluxes, gamma and hard X-ray emission will constitute too harsh an environment to permit the use of classical semiconductor detectors. New SXR detector technologies, more robust to such environments, should thus be investigated. First GEM (Gas Electron Multiplier) measurements performed at WEST were successful and showed that both spatially and spectrally resolved calibrated data could be acquired. Strategies to reconstruct tungsten (W) impurity radiation synthetic diagnostics, modelling and real measurements based on multiple diagnostics are proposed.
The complexity of quantum experimentation setups generates demand for a hardware platform that ensures means of standardization of the equipment used as well as setup repeatability.Sinara Hardware is an open-source answer to those challenges. It offers a modular architecture and well over 50 different modules. While originating from ion trapping experiments, it provides an ecosystem that can meet a wide range of quantum experimentation needs. Accompanied by researchers and engineers from different universities and private companies, Sinara Hardware is not only a hardware platform but also a vibrant community.Sinara Hardware is developed along with an open-source control system - ARTIQ. ARTIQ provides a high-level programming interface along with experiment management tools. It offers nanosecond timing accuracy, sub-microsecond latency and means of timing distribution across several controller modules.This poster covers the developments from the last 2 years in the Sinara Hardware project. The most interesting novelties are: CERN Distributed IO Tier (DIOT) integration that will introduce backplane for communication and will enable use of DIOT Zynq UltraScale+ based controller; Artix-7 based FMC (FPGA Mezzanine Card) carrier along with two Sinara-dedicated FMCs: Shuttler - 125 MSPS 16 ch. 16-bit DAC (Digital to Analog Converter), with separate analog front end for application versatility and Waver - 1.5 GSPS 4 ch. 16-bit DAC; Unified Arbitrary Waveform Generator Framework as a common firmware platform for Sinara DAC applications as well as Xilinx RFSoC-based high bandwidth signal generator. Additionally, an overview of what is to be expected in future developments is shown.
In this article, a cost-effective and fast interrogating system for wide temperature measurement with Fiber Bragg Gratings is presented. The system consists of a Vertical Cavity Surface Emitting Laser (VCSEL) with a High Contrast Grating (HCG)-based cavity that allows for the fast tuning of the output wavelength. The work focuses on methods of bypassing the limitations of the used VCSEL laser, especially its relatively narrow tuning range. Moreover, an error analysis is provided by means of the VCSEL temperature instability and its influence on the system performance. A simple proof of concept of the measurement system is shown, where two femtosecond Bragg gratings were used to measure temperature in the range of 25 to 800 °C. In addition, an exemplary simulation of a system with sapphire Bragg gratings is provided, where we propose multiplexation in the wavelength and reflectance domains. The presented concept can be further used to measure a wide range of temperatures with scanning frequencies up to hundreds of kHz.
The work describes a novel approach to the design of a fast, multichannel measurement system for plasma diagnostics [A. Wojenski et al., Fusion Eng. Des. 123, 727 (2016)]. Its main scope is to provide measurements of soft X-ray (SXR) emission during plasma phenomena at the W-Environment in Steady-state Tokamak (WEST), especially for monitoring and tracing tungsten impurities. This paper describes the vertical Gas Electron Multiplier (GEM) camera installed at the WEST [M. Chernyshova et al., J. Instrument. 10, P10022 (2015)]. The designed GEM detector readout board has more than 100 channels, resulting in high-performance requirements for the data acquisition and processing system. The novel system construction approach is that the unit works on the raw signals providing a high quality of the data, especially in the scope of pileup effect analysis. In the case of doubtful results, the source data can be easily reviewed offline. The data selection and transmission are done in Field-Programmable Gate Arrays (FPGAs) on the custom boards with the custom Peripheral Component Interconnect (PCI)-Express Gen2 switch that allows us to register signals from multiple FPGAs and then process the data by complex algorithms [G. Kasprowicz et al., J. Fusion Energy 38, 480 (2019)]. The firmware is replaceable and different working modes can be applied (some under verification): global trigger mode, high-speed data serialization, and extended signal registration. Low level optimized central processing unit software for data readout was also designed [P. Linczuk et al., J. Instrum. 14, C05001 (2019)]. The installation of the system is described due to complex system components' distribution. The first results of the successful acquisition of the plasma at the WEST are discussed. The corresponding SXR energy and topology spectra were computed. Those are the first technical measurements of the system to ensure verification of data quality.
The validation of the measurements quality after on-site diagnostic system installation is necessary in order to provide reliable data and output results. This topic is often neglected or not discussed in detail regarding measurement systems. In the paper recently installed system for soft X-ray measurements is described in introduction. The system is based on multichannel GEM detector and the data is collected and sent in special format to PC unit for further postprocessing. The unique feature of the system is the ability to compute final data based on raw data only. The raw data is selected upon algorithms by FPGA units. The FPGAs are connected to the analog frontend of the system and able to register all of the signals and collect the useful data. The interface used for data streaming is PCIe Gen2 x4 for each FPGA, therefore high throughput of the system is ensured. The paper then discusses the properties of the installation environment of the system and basic functionality mode. New features are described, both in theoretical and practical approach. New modes correspond to the data quality monitoring features implemented for the system, that provide extra information to the postprocessing stage and final algorithms. In the article is described also additional mode to perform hardware simulation of signals in a tokamak-like environment using FPGAs. The summary describes the implemented features of the data quality monitoring features and additional modes of the system.
Trapping ions, performing qubit operations and quantum multi-qubit gates require complex pulse spectra on several frequency bands. The Smart Arbitrary Waveform Generators (SAWG) Sayma and Phaser are designed to trap control and generate the Short-time Fourier transform (STFT) pulses. They have quad channels of over 1.2 GS/s (Giga Samples per second) 16-bit DACs and a few MS/s (Mega Samples per second) ADCs. These modules are dedicated to implementing qubit operations, both optically and electronically. The Sayma and Phaser modules are part of the Sinara family - a modular, open-source measurement and control hardware ecosystem dedicated to quantum applications that require deterministic high-resolution timing. The hardware is controlled and managed by the ARTIQ open-source software platform, which provides nanosecond timing resolution and sub-microsecond latency via a high-level programming language. We present the Sayma and the Phaser construction and obtained characteristics.
Thermonuclear fusion will be a promising energy source soon. Sophisticated systems are called tokamaks (toroidal chambers with magnetic coils) to generate hot plasma. Currently, the fusion process is not yet fully controlled. To better understand it, scientists use diagnostic systems that record plasma behavior. A particular group of diagnostic systems is responsible for the analysis of plasma impurities. The article briefly discusses the method of producing energy from a controlled nuclear fusion. Then, it presents groups of diagnostic systems in terms of their functions and focuses on systems dedicated to monitoring and analyzing plasma impurities. Parameters and limitations of representative currently used diagnostics systems for plasma impurities are described. In the end, the functional and technical requirements of plasma diagnostic systems designed for new tokamaks such as ITER and DEMO are discussed.
This contribution outlines the first preliminary acquisition data obtained by the GEM diagnostics on WEST. It was designed to monitor the radiation of impurities with a particular focus on the challenges of the elaborated plasma imaging technology in the area of SXR radiation. The details of the developed diagnostics and preliminary results obtained within the commissioning phase of the diagnostics at the WEST Project are provided. It is shown that both spatially and spectrally resolved calibrated data could be collected. A comparison with other WEST diagnostics manifests good qualitative agreement. Currently, the developed system records rather high energy part of the SXR radiation (above 4 keV), that nevertheless still could be useful to assess an intensification of the erosion.
—The paper presents improvements of the developed system for hot plasma radiation measurement in the soft X-ray range based on a Gas Electron Multiplier (GEM) detector. Scope of work consists of a new solution for handling hardware time-synchronization with tokamak systems needed for better synchronization with other diagnostics and measurement quality. The paper describes the support of new modes of triggering on PC-side. There are communication and data path overview in the system. The new API is described, which provide separate channels for data and control and is more robust than the earlier solution. Work concentrates on stability and usability improvements of the implemented device providing better usage for end-user.
Data quality of the tokamaks diagnostics is often a neglected topic. In literature it is rather rare to find considerations regarding the data quality received from the diagnostic systems' sensors. The scope of the paper is to provide a discussion regarding systems' construction and analysis in scope of implementation of data quality monitoring methods for a new generation of diagnostics. Mainly considerations are performed regarding the necessity of DQM (Data Quality Monitoring) implementation, functionality, performance and required system resources. The covered topics are related to basics of system construction including: system layout and construction blocks, data processing stages, signal processing modes, system construction with resource estimation in scope of DQM implementation. Based on the covered points, it is possible to plan the extra resources or specific construction, to provide reliable design with data quality monitoring features. The data quality monitoring aspect is especially important in the modern diagnostics working with a real-time feedback loop. Such approach could be especially interesting for the ITER-like projects, since the quality of the data may directly influence the behavior of the control systems during plasma phenomena. The work is based on experience in design work of various high performance diagnostic systems for plasma physics and high energy physics.
A novel approach to a trigger mode in the Gas Electron Multiplier (GEM) detector readout system is presented. The system is already installed at WEST tokamak. The article briefly describes the architecture of the GEM detector and the measurement system. Currently the system can work in two trigger modes: Global Trigger and Local Trigger. All trigger processing blocks are parts of the Charge Signal Sequencer module which is responsible for transferring data to the PC. Therefore, the article presents structure of the Sequencer with details about basic blocks, theirs functionality and output data configuration. The Sequencer with the trigger algorithms is implemented in an FPGA chip from Xilinx. Global Trigger, which is a default mode for the system, is not efficient and has limitations due to storing much data without any information. Local trigger which is under tests, removes data redundancy and is constructed to send only valid data, but the rest of the software, especially on the PC side, is still under development. Therefore authors propose the trigger mode which combines functionality of two existing modes. The proposed trigger, called Zero Suppression Trigger, is compatible with the existing interfaces of the PC software, but is also capable to verify and filter incoming signals and transfer only recognized events. The results of the implementation and simulation are presented.
Sinara is a control system dedicated to quantum applications. It is based on industrial standards and consists of over 50 modules. The hardware is controlled by ARTIQ, which provides a high-level programming language.
This article discusses the construction of a prototype of a platform that provides the integration of video signals from multiple sources. Video sources can be both existing CCTV systems based on analog cameras, modern systems based on IP cameras and individual cameras of various types. The system consists of portable units that provide signal conversion, its encoding, video streaming and transmission over IP protocols. A distributed and modular prototype of the VSI system was developed. The system consists of modular devices that integrate video streams, user terminals and central system. The VSI prototype provides simultaneous access to a large number of real- time video streams . The system is fully modular, which enables easy expansion of both hardware and software. The article presents the obtained architecture and exemplary operating results.
The paper presents latency and performance study of the monitoring system for plasma impurities radiation in a tokamak. The developed solution measures radiation in Soft X-Ray range and can provide valuable information about the ongoing experiment with low latency. This work presents the test configuration with a single-dimensional pixel topology, with 64 channels, tested at photon rate about 100 kHz per channel. The hardware consists of the GEM-based detector, FPGAs, PCIe transmission system and the computer system with 64-bit x86 architecture. The software is the C/C++ code optimized for the execution time and working in the global trigger mode. The system uses raw data acquisition and the backend computations in CPU to provide high accuracy and high-quality results, not easily achievable otherwise. The research includes measurements of the throughput of the system and the latency of the whole data path - between the pulse detection in FPGA and storing of spectroscopy histograms in the file system in memory. The direction of improvements and further development were proposed.
Gas electron multiplier (GEM) detectors (Sauli in Nucl Instrum Methods Phys Res A 805:2–24, 2016. https://doi.org/10.1016/j.nima.2015.07.060 (special issue in memory of Glenn F. Knoll); Buzulutskov in Instrum Exp Tech 50(3):287–310, 2007. https://doi.org/10.1134/S0020441207030013) are widely used for detection of ionizing radiation. When used in the proportional mode, they provide information about time, location, and energy of a detected particle (Chernyshova et al. in Fusion Eng Design, 2017. https://doi.org/10.1016/j.fusengdes.2017.03.107; Altunbas et al. in Nucl Instrum Methods Phys Res A 490(1–2):177–203, 2002. https://doi.org/10.1016/S0168-9002(02)00910-5. http://linkinghub.elsevier.com/retrieve/pii/S0168900202009105). Modern technologies allow full utilization of detector properties, by acquiring the waveform of output current pulses and processing them using sophisticated digital signal processing (DSP) algorithms. The current pulses must be digitized at high speed (up to 125 MHz) with high resolution (up to 12-bits). Due to the high volume of the produced data, it is necessary to provide the high-performance data acquisition system (DAQ) to transmit the data to processing units. Efficient processing of the GEM data requires distributed parallel processing system to perform multiple tasks (Czarski et al. in Rev Sci Instrum 87(11), 11E336, 2016. https://doi.org/10.1063/1.4961559): (1) Filter out the background and transmit only hit related data. (2) Extract the parameters of a hit, describing the time and charge (related to energy). (3) Estimate the hit position by combining information from multiple anode pads. (4) In case of 2D GEM detectors, correlate pulses received from X and Y pads (pixels) or W, U and V pads (pixels). (5) Separate the hits overlapping in space or in time (if possible) to support detector operation at higher rates. The above functionalities may be achieved in different hardware architectures. The typical hardware platforms include FPGA chips, standard or embedded computer systems with different computation accelerators (Wojenski et al. in J Instrum 11(11):C11035, 2016. http://stacks.iop.org/1748-0221/11/i=11/a=C11035; Nowak et al. in J Phys Conf Ser 513(5):052–024, 2014. https://doi.org/10.1088/1742-6596/513/5/052024. http://stacks.iop.org/1742-6596/513/i=5/a=052024?key=crossref.c5912cfa72c30b309821e14c4384948f. The paper shows possible solutions with their feasibility for particular applications.
SummaryThis paper presents feasibility studies in utilizing graphics processing units (GPUs) as high‐performance computing hardware with front‐end electronics in high‐scale magnetic confinement thermal fusion experiments. The objective of the research is to provide scalable, high‐throughput, and low‐latency measurements for the runtime tokamak metallic impurities X‐ray diagnostic for the Tungsten Environment in Steady‐State Tokamak (WEST) reactor. The heterogeneous system of front‐end with field‐programmable gate arrays and the back‐end server was introduced to decompose workloads efficiently. It allows the comprehensive evaluation of CPUs and accelerators. In particular, a novel implementation of the back‐end algorithm for GPU with the performance analysis are presented.
The article presents the latest updates in the development of automated cage for optogenetic experiments. The new RFID module allows detecting the presence of mice in a given area of the cage. A brief description of the hardware and software parts has been presented.
The search for new technologies in the field of plasma diagnostics entails the increasing demands on the radiative stability of the used materials due to development and usage of fusion facilities, where the study of processes occurring during the interaction of radiation with matter has become particularly important. Currently, a new X-ray imaging detection technology is required for tokamaks such as ITER. X-ray detectors that are being used in existing equipment may rapidly degrade due to large neutron fluxes characteristic for the tokamak environment. Despite the relatively wide use of semiconductor detectors to record SXR radiation (generally ionizing radiation), gas detectors are promising candidates that are suited much better for use in future fusion reactors given their resistance to neutron radiation. The most promising representative of the new gas detector class is the so called Gas Electron Multiplier (GEM), which is characterized by high amplification factor of the primary charge that is originated from photon absorption. Its main advantages are the compactness of the detector, good temporal and spatial resolutions, the ability to discriminate against photon energy and better neutron resistance compared to existing systems. All this makes such a detection system a potentially better candidate for soft X-ray measurements in the ITER and DEMO reactors. In this work, a new type of detection system based on GEM technology was proposed for soft X-ray measurements in the ITER reactor-oriented research, which is being developed at IPPLM.
The presented system is used for monitoring of the plasma impurities in the tokamak. It is done by measuring radiation in Soft X-Ray range with the use of a GEM-based detector. Acquired data is transferred through the whole system with low latency. Presented system can be divided into many parts - detector, analog electronics, FPGA, PCIe transmission line and computer system with high-performance CPU. This work will concentrate on synchronization between FPGA, which write data to the memory on the CPU side and computational part, which is executed in the computer. In long-running measurements, there is a synchronization problems which can arise. There is a difference in variables based on which the execution time of both parts is dependent. Working on measurements of radiation of plasma impurities requires limits in terms of latency. This paper presents reasons, descriptions and solutions for such problems.