Search Results (12)

The fusion energy research field presents many intricate challenges that require resolution. Many diagnostic systems employed in experiments are approaching the limits of current technology. Implementing efficient measurements requires using an appropriate set of tools to facilitate the optimal utilization of hardware. Fusion energy measurements must provide low latency processing with the capacity for future improvements and the ability to handle complex data flows efficiently. The presented work addresses these requirements and describes the implementation of a high-performance, low-latency software platform with convenient development for soft X-ray (SXR) plasma impurities emission tracing—the Asynchronous Complex Computation Platform (AC2P). This article presents the architectural design, implementation details, and performance and latency measurements based on the raw data acquired from the WEST tokamak and laboratory tests. AC2P provides the tools to develop low-latency, multi-core, multi-device complex data flow graph scale-up solutions for measuring impurities in hot plasmas. The system has been designed to operate online during experiments, calculate the energy distribution, position and occurrence time of SXR photons, monitor the data stream’s quality and archive any abnormalities for subsequent offline verification and algorithm improvement. This article presents AC2P, which operates as part of the SXR measurement system on the WEST tokamak. Full article

In this paper, we report on a systematic study of a soft X-ray Gas Electron Multiplier (GEM) detector built with aluminium-clad kapton GEM foils. The primary objective of this research is to comprehend the performance of this type of detector when irradiated with soft energy photons. The results are analysed and discussed with a particular focus on the long-term detector stability, as well as its gas gain and energy resolution uniformity across the detector area. Presented results lead us to the conclusion that the aluminium based GEM detector is a promising device to suppress the X-ray Fluorescence (XRF) background, simultaneously providing very good stability during long-term measurement campaigns. Full article

Optical readout of large scale dual-phase liquid Argon TPCs is an attractive alternative to charge readout and has been successfully demonstrated on a 2 × 2 m active region within the CERN protoDUNE cold box. ARIADNE${}^{+}$ uses four Timepix3 cameras imaging the S2 light produced by 16 novel, patent pending, glass THGEMs. ARIADNE⁺ takes advantage of the raw Timepix3 data coming natively 3D and zero suppressed with a 1.6 ns timing resolution. Three of the four THGEM quadrants implement readouts in the visible light range through wavelength shifting, with the fourth featuring a VUV light intensifier, thus removing the need for wavelength shifting altogether. Cosmic ray reconstruction and energy calibration were performed. Presented is a summary of the detector setup and experimental run, preliminary analysis of the run data and future outlook for the ARIADNE program. Full article

The goal of the work was to investigate the possible application of factor analysis methods for processing X-ray Fluorescence (XRF) data acquired with a full-field XRF spectrometer employing a position-sensitive and energy-dispersive Gas Electron Multiplier (GEM) detector, which provides only limited energy resolution at a level of 18% Full Width at Half Maximum (FWHM) at 5.9 keV. In this article, we present the design and performance of the full-field imaging spectrometer and the results of case studies performed using the developed instrument. The XRF imaging data collected for two historical paintings are presented along with the procedures applied to data calibration and analysis. The maps of elemental distributions were built using three different analysis methods: Region of Interest (ROI), Non-Negative Matrix Factorisation (NMF), and Principal Component Analysis (PCA). The results obtained for these paintings show that the factor analysis methods NMF and PCA provide significant enhancement of selectivity of the elemental analysis in case of limited energy resolution of the spectrometer. Full article

This paper details a novel, patent pending, abrasive machining manufacturing process for the formation of sub-millimetre holes in THGEMs, with the intended application in gaseous and dual-phase TPCs. Abrasive machining favours a non-ductile substrate such as glasses or ceramics. This innovative manufacturing process allows for unprecedented versatility in THGEM substrates, electrodes, and hole geometry and pattern. Consequently, THGEMs produced via abrasive machining can be tailored for specific properties: for example, high stiffness, low total thickness variation, radiopurity, moisture absorption/outgassing and/or carbonisation resistance. This paper specifically focuses on three glass substrate THGEMs (G-THGEMs) made from Schott Borofloat 33 and fused silica. Circular and hexagonal hole shapes are also investigated. The G-THGEM electrodes are made from indium tin oxide (ITO), with a resistivity of 150 $\mathsf{\Omega }$/Sq. All G-THGEMs were characterised in an optical (EMCCD) readout GArTPC and compared to a traditionally manufactured FR4 THGEM, with their charging and secondary scintillation (S2) light production behaviour analysed. Full article

Liquid Argon (LAr) is one of the most widely used scintillators in particle detection, due to its low cost, high availability and excellent scintillation properties. A large number of experiments in the neutrino sector are based around using LAr in one or more Time Projection Chambers (TPCs), leading to high resolution three-dimensional particle reconstruction. In this paper, we review and summarise a number of these Liquid Argon Time Projection Chamber (LArTPC) experiments, and briefly describe the specific technologies that they currently employ. This includes single phase LAr experiments (ICARUS T600, MicroBooNE, SBND, LArIAT, DUNE-SP, ProtoDUNE-SP, ArgonCube and Vertical Drift) and dual phase LAr experiments (DUNE-DP, WA105, ProtoDUNE-DP and ARIADNE). We also discuss some new avenues of research in the field of LArTPC readout, which show potential for wide-scale use in the near future. Full article

The Fast Timing Micro-Pattern Gaseous Detector (FTM) has been recently introduced as a promising alternative for applications that require improved time resolution, such as high-luminosity accelerators and medical imaging. The FTM consists of a stack of several coupled gas layers alternating drift and multiplication stages. The time resolution is determined by the time of the fastest signal among all amplification stages, read out by external electrodes through capacitive couplings. In the present work, we use the Garfield++ simulation toolkit in order to investigate and optimize the FTM performances. Gain, timing, and efficiency of the FTM are studied as a function of different parameters, such as detector geometry, gas mixture, and applied electric fields. The simulations that are presented in this paper show that a time resolution as low as 160 ps can be reached with a 32-layers FTM. Full article

The ARIADNE Experiment, utilising a 1-ton dual-phase Liquid Argon Time Projection Chamber (LArTPC), aims to develop and mature optical readout technology for large scale LAr detectors. This paper describes the characterisation, using cosmic muons, of a Timepix3-based camera mounted on the ARIADNE detector. The raw data from the camera are natively 3D and zero suppressed, allowing for straightforward event reconstruction, and a gallery of reconstructed LAr interaction events is presented. Taking advantage of the 1.6 ns time resolution of the readout, the drift velocity of the ionised electrons in LAr was determined to be 1.608 ± 0.005 mm/$\mathsf{\mu }$s at 0.54 kV/cm. Energy calibration and resolution were determined using through-going muons. The energy resolution was found to be approximately 11% for the presented dataset. A preliminary study of the energy deposition ($\frac{dE}{dX}$) as a function of distance has also been performed for two stopping muon events, and comparison to GEANT4 simulation shows good agreement. The results presented demonstrate the capabilities of this technology, and its application is discussed in the context of the future kiloton-scale dual-phase LAr detectors that will be used in the DUNE programme. Full article

In this paper, an online vertex reconstruction algorithm based on an artificial neural network (ANN) was proposed for the micro-pattern gaseous detector (MPGD). A simulation based on Geant4 was performed to generate the training and testing samples for the two cascade neural networks. Compared with a center-of-mass reconstruction, the proposed method shows better precision and much higher efficiency. Furthermore, a scheme for implementing the proposed algorithm on a Field-Programmable Gate Array (FPGA) chip is also presented to demonstrate that the algorithm could be integrated in a modern data acquisition (DAQ) system for online imaging techniques. Full article

In this paper, we report on the systematic study of different variants of X-ray detectors based on Gas Electron Multiplier (GEM) technology using modified GEM foils with greatly reduced amount of copper. The main goal of this study was understanding the performance of such detectors applied in X-Ray Fluorescence (XRF) elemental analysis. Reduction of the amount of copper in the detector structure is crucial for suppression of XRF background from copper, but one has to ensure that key detector parameters are not affected by such modification. The tested detector variants include detectors with different types of copper-less GEM foils, which have been manufactured starting from standard copper-clad foils and removing partially the copper layer in additional post-processing steps. The results are analyzed and discussed with a particular focus on the energy resolution, uniformity of gas gain and energy resolution across the detector area, and on the long-term stability of the gas gain. Long-term stability tests performed for selected detectors do not indicate for any accelerated aging of the copper-less detectors compared to standard detectors using copper-clad GEM foils. The presented results lead us to conclude that the copper-less GEM detectors are promising devices to suppress the XRF background. Full article

Due to the so-called ³He shortage crisis, many detection techniques for thermal neutrons are currently based on alternative converters. There are several possible ways of increasing the detection efficiency for thermal neutrons using the solid neutron-to-charge converters ¹⁰B or ¹⁰B₄C. Here, we present an investigation of the Micromegas technology. The micro-pattern gaseous detector Micromegas was developed in the past years at Saclay and is now used in a wide variety of neutron experiments due to its combination of high accuracy, high rate capability, excellent timing properties, and robustness. A large high-efficiency Micromegas-based neutron detector is proposed for thermal neutron detection, containing several layers of ¹⁰B₄C coatings that are mounted inside the gas volume. The principle and the fabrication of a single detector unit prototype with overall dimension of ~15 × 15 cm² and its possibility to modify the number of ¹⁰B₄C neutron converter layers are described. We also report results from measurements that are verified by simulations, demonstrating that typically five ¹⁰B₄C layers of 1–2 μm thickness would lead to a detection efficiency of 20% for thermal neutrons and a spatial resolution of sub-mm. The high potential of this novel technique is given by the design being easily adapted to large sizes by constructing a mosaic of several such detector units, resulting in a large area coverage and high detection efficiencies. An alternative way of achieving this is to use a multi-layered Micromegas that is equipped with two-side ¹⁰B₄C-coated gas electron multiplier (GEM)-type meshes, resulting in a robust and large surface detector. Another innovative and very promising concept for cost-effective, high-efficiency, large-scale neutron detectors is by stacking ¹⁰B₄C-coated microbulk Micromegas. A prototype was designed and built, and the tests so far look very encouraging. Full article

Several recent detector technologies developed for particle physics applications are based on microfabricated structures. Detectors built with this approach generally exhibit the overall best performance in terms of spatial and time resolution. Many properties of the SU-8 photoepoxy make it suitable for the manufacturing of microstructured particle detectors. This article aims to review some emerging detector technologies making use of SU-8 microstructuring, namely micropattern gaseous detectors and microfluidic scintillation detectors. The general working principle and main process steps for the fabrication of each device are reported, with a focus on the advantages brought to the device functionality by the use of SU-8. A novel process based on multiple bonding steps for the fabrication of thin multilayer microfluidic scintillation detectors developed by the authors is presented. Finally, a brief overview of the applications for the discussed devices is given. Full article