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Spectroscopy, electronic structure and quantification attempt in the spectral range of the Li Kα emission band
No full textIn this work, we present the way we perform high-resolution wavelength-dispersive X-ray spectrometry in the ultra-soft X-ray range. For this purpose, we use a reflection zone plate spectrometer working, as a variable line spacing grating spectrometer, in the 40 - 110 eV spectral range. We show that the shape of the emission bands can be reproduced by simulation of spectra obtained from the local and partial density of states calculated with the density functional theory. The knowledge of the electronic structure of the material under consideration is important to properly interpret the spectra, which can be complicated when many elements are present in the sample, such as the amblygonite phosphate. We also show the first attempt of elemental quantification of an AlCuLi alloy from intensities measured with the reflection zone plate spectrometer. The obtained mass fractions are in good agreement with those obtained in a standard way from measurements performed in the soft X-ray range with crystal spectrometers
Experiments and fuel reloads optimization for the Jules Horowitz Reactor (JHR) using a genetic algorithm combined with a convolutional neural network
No full textThis paper presents the experiments and fuel reloads optimization of the Jules Horowitz research Reactor (JHR) using a genetic algorithm coupled with a convolutional neural network. At the end of a cycle, the most burned fuel elements will be removed and replaced by fresh fuel elements. Since the purpose of this reactor is to conduct experiments, it is crucial to reach experimental performances. With this aim, the goal was to find the best location for each fuel element for the next cycle, i.e. the optimal core configuration that satisfies not only operations and safety constraints but also experimental goals. The analysis was based on an algorithm using two Python libraries: PyGAD for the genetic algorithm and TensorFlow for the convolutional neural network, thus providing a simple implementation of the method. It has been shown the convolutional neural network predicts the core parameters in 12 ms with a low error. Moreover, the genetic algorithm converges toward an optimal core configuration in a very short computation time (∼7.5 minutes) as well. This paper demonstrates that the combination of a convolutional neural network and a genetic algorithm allows obtaining the optimal core configuration for a research reactor in particular to maximize its experimental performances
Design, Manufacturing, and Installation of DIII-D Lower Hybrid Current Drive Outer Wall Waveguides and Expandable Vacuum Interface
No full textHigh field side lower hybrid current drive (HFS LHCD) is promising method for efficient, off axis current drive. To operate this system, development of an expandable combination radio frequency (RF) and vacuum interface was necessary to allow the long (~2 m) waveguides to thermally expand with respect to the DIII-D 0 degree R-1 port extension without damage to the waveguide or excessive force on the vacuum seals which was previously observed when baking the waveguides during operations that were installed in 2024. Design of a custom bellows assembly with RF feedthrough that allows >20mm of waveguide thermal expansion is presented. Fabrication of this bellows assembly required simultaneously vacuum brazing multiple 304 stainless steel flanges to an oxygen free high conductivity copper waveguide section which required significant manufacturing development
40 years of ICRF operation on JET: Challenges and achievements
No full textAfter 40 years of successful operation and multiple Deuterium-Tritium (D-T) campaigns, the Joint European Torus (JET) concluded its operations in December 2023. From the outset, Ion Cyclotron Range of Frequency (ICRF) heating was identified as a key auxiliary heating system, with the first ICRF system becoming operational in 1985. This system underwent significant development, culminating in a high-power (32 MW installed), wideband (23-57 MHz range), and highly versatile system. This contribution provides an overview of the JET RF system’s evolution over its lifetime, highlighting selected operational challenges and technological achievements. It addresses the rationale behind the development and operation of the ICRF system, including the implementation and operation of load-resilient systems (3 dB hybrid coupler, External Conjugate-T, ILA), as well as the operational limits and system protection measures, such as the specific mode of operation for Ion Cyclotron Wall Conditioning (ICWC). The impact of transitioning from a carbon wall to the JET-ILW metal wall (tungsten divertor and beryllium first wall) on the system’s operation and the challenges posed by D-T operations are also emphasized. Finally, key lessons learned from the technical challenges, constraints, and achievements of the JET experience are highlighted, with an eye towards the design and operation of ICRF systems in future machines
ICRH modelling of the Baseline D-T scenario in JET
No full textIn the 2021 and 2023 D-T campaigns in JET various scenarios with potential for application in fusion reactors have been studied. The mandate of the “Baseline” experiments was to explore the possibility to operate at high density, magnetic field and current. Although extremely promising results were obtained in D plasmas in the running-up to the actual D-T campaign and up to 8MW of fusion power was produced when adopting this scenario in D-T [1],[2], it was - in contrast to the record T-rich scenario [3] - not possible to sustain D-T shots for the envisaged 5 seconds while also steadily producing more than 10MW of fusion power. In view of the Baseline being considered as a prime candidate for maintaining a high-density plasma in future machines, the underlying reasons are still being explored to enable offering perspectives for possible cures for next-generation experiments. The present paper contributes to that: It concentrates on the detailed modelling of auxiliary (RF & NBI) heating aspects and on the synergy between them, allowing a better understanding of the key role of the auxiliary heating in these high-performance shots. It complements papers that concentrated on key - interrelated - aspects such as transport (see e.g. [4]), MHD (see e.g. [5]), impurities [6, 7], pedestal dynamics [8] and control [9]. One aspect setting the scenarios tested in D-T apart and which has several repercussions is that the Baseline plasma current and hence the density is higher and flatter. This allows to profit optimally from the fact that the neutron rate is proportional to the densities of the fusion fuel ions. However, the higher density affects the beam penetration and modifies the collisionality as well as the beam power deposition profiles. This has nonnegligible implications, some of which will be discussed here
Fast impedance matching for the ion cyctron resonance heating system based on capacitors at the EAST tokamak
No full textThis paper presents an impedance matching system based on real-time feedback control, designed to address impedance mismatching issues in radio frequency (RF) systems. The proposed system integrates a directional coupler, a double-section impedance matcher, a variable capacitor, a servo motor, and a fast real-time impedance matching feedback control system. By measuring forward and reflected power via the directional coupler, the system dynamically adjusts the capacitance to achieve optimal matching. The real-time feedback mechanism controls the servo motor to adjust the capacitor’s value, thereby fine-tuning to the desired level. Experimental results show that the system can significantly reduce reflection power in less than 1 second, demonstrating fast response and high efficiency. The proposed solution is applicable in wireless communication, radar, and RF power transmission systems, offering improved system performance, reduced energy consumption, and enhanced signal quality
Time-dependent modelling of 104/137 GHz X2-mode ECRH on ST40 to aid future scenario development
No full textWith a multi-Tesla magnetic field and the capability to achieve fusion-relevant ion temperatures, the ST40 experiment is uniquely positioned as a high-performance spherical tokamak on which to test reactor-relevant technologies. This will be further augmented by the addition of a 104/137 GHz dual-frequency gyrotron supplied by Kyoto Fusioneering Ltd capable of delivering 2s pulses of 1 MW EC power. Here we demonstrate the new capabilities afforded by the additional ECRH through time-dependent integrated modelling in TRANSP. Using two different reference shots, we find that, although accessibility constraints make it difficult to directly drive EC current, the 1MW 104 GHz X2-mode ECRH is nevertheless capable of reducing the loop voltage by increasing the bootstrap current via direct electron heating. The safety-factor profile is also strongly modified, attaining reverse shear in one scenario. More flexibility in the EC launcher geometry will be gained by increasing the magnetic field from 1.8 to 2.4 T; in this case, X2-mode ECRH at 137 GHz could be used instead, which will not suffer any accessibility constraints at typical ST40 densities
BaBy cosmic tension
No full textWe show that the recently released B-mode polarisation data from the South Pole Telescope (SPT) favour a non-vanishing contribution of primordial gravitational waves of inflationary origin which is in tension with the previous BICEP-Keck (BK) measurements. Our analysis uses the third-order slow-roll primordial power spectra, with theoretically motivated priors, on the multifrequency SPT likelihoods complemented by the latest Planck satellite data products. The SPT measurements provide 1.0 bit of information gain on the first slow-roll parameter, which is higher than the 0.9 bit provided by BK even though the SPT sensitivity is five times lower. Moreover, the Bayesian dimensionality on the same parameter exceeds 1.5 for SPT vs. 0.3 for BK showing that it is overconstrained by the SPT data. Even if this could be the result of a yet to be understood foreground, our findings should motivate for a closer analysis of this unexpected B-modes excess
Comprendre les biais de genre dans le diagnostic, le traitement et la prise en charge médicale
No full textEn médecine, les biais de genre influencent le diagnostic, le traitement et la prise en charge des personnes qui consultent. Fondés à la fois sur une méconnaissance des besoins spécifiques liés au sexe et au genre, ainsi que sur des stéréotypes, ils faussent l’interprétation des symptômes de même que les décisions cliniques et thérapeutiques. Si certaines différences de prise en charge liées au sexe peuvent être cliniquement justifiées, car elles relèvent de l’équité en santé, d’autres traduisent des inégalités injustifiées. À partir d’exemples concrets, cet article examine leurs effets sur la pratique médicale et sur la qualité des soins, et souligne l’importance d’une formation adaptée des personnes exerçant dans le domaine de la santé
Development and Quality Evaluation of Coconut Milk Products Enriched with Flaxseed Powder
No full textCoconut milk is a lactose-free plant-based milk alternative widely consumed in Indonesia. This study developed coconut milk enriched with flaxseed powder to improve its nutritional and functional properties. Four formulations were prepared: control (0% flaxseed), A (3%), B (5%), and C (7%). Samples were analysed for proximate composition, physical properties (pH, colour, viscosity, total dissolved solids), antioxidant activity, total phenolic content, and sensory acceptance. Flaxseed addition significantly increased protein, fat, carbohydrate, viscosity, brightness (L*), yellowness (b*), AE, antioxidant activity, and total phenolics, while pH and redness (a*) decreased. Moisture and ash content were not significantly affected. The highest antioxidant activity (72.92%) and phenolic content (147.64 mg/L) were observed in Formula C. Sensory evaluation indicated that Formula A achieved the highest scores for overall liking, taste, aroma, and visual appeal, and was ranked most preferred (mean ranking 1.58). Higher flaxseed levels reduced acceptability due to increased bitterness and excessive thickness. Overall, incorporating 3% flaxseed powder into coconut milk produced a nutritionally enhanced beverage with optimal sensory acceptance, offering a promising lactose-free functional drink