This article covers the in-vessel design of the SPARC interferometry diagnostic system, highlighting unique aspects of the systems design and port plug integration in preparation for "day-1" plasma operations as a critical diagnostic for density feedback control. An early decision for the diagnostic was to deploy two lasers in the infrared wavelength spectrum, allowing the system to have a higher optical throughput. The optimization of the in-vessel geometry for the diagnostic follows a similar approach, focusing on de-risking possible damage to the plasma facing optical components by moving them further from the plasma with an orientation that provides a greater possibility for protective features to be added.
View Article and Find Full Text PDFThe design of a compact 2 × 2 diamond matrix with independent and redundant pixels optimized for the spectrometric neutron camera of the SPARC tokamak is presented in this article. Such a matrix overcomes the constraints in dynamic range posed by the size of a single diamond sensor while keeping the ability to perform energy spectral analysis, marking a significant advancement in tokamak neutron diagnostics. A charge pre-amplifier based on radio frequency amplifiers based on InGaP technology transistors, offering up to 2 GHz bandwidth with high robustness against radiation, has been developed.
View Article and Find Full Text PDFRev Sci Instrum
October 2024
The SPARC tokamak is a high-field, Bt0 ∼12 T, medium-sized, R0 = 1.85 m, tokamak that is presently under construction in Devens, MA, led by Commonwealth Fusion Systems. It will be used to de-risk the high-field tokamak path to a fusion power plant and demonstrate the commercial viability of fusion energy.
View Article and Find Full Text PDFA suite of plasma diagnostics will be installed on the SPARC tokamak to allow for real-time plasma control, an investigation of high-field tokamak physics, and to de-risk the design of ARC, a compact fusion power plant with the aim to supply electricity to the grid. Among these diagnostics is the neutral gas diagnostics system (NTGS), a set of pressure sensors and gas analyzers used to monitor neutral pressure and gas composition for plasma control, optimization of wall conditioning, and helium ash removal, among other measurement functions linked to operational and scientific research needs. While reliable measurements of neutral pressure and gas composition have been fielded on existing magnetic-confinement fusion devices, SPARC represents a step increase in challenge due to its larger power density, higher field, high vacuum vessel bake temperatures, and higher neutron flux environment, as well as a step decrease in the accessibility for maintenance of in-vessel sensors.
View Article and Find Full Text PDFNeutron measurement is the primary tool in the SPARC tokamak for fusion power (Pfus) monitoring, research on the physics of burning plasmas, validation of the neutronics simulation workflows, and providing feedback for machine protection. A demanding target uncertainty (10% for Pfus) and coverage of a wide dynamic range (>8 orders of magnitude going up to 5 × 1019 n/s), coupled with a fast-track timeline for design and deployment, make the development of the SPARC neutron diagnostics challenging. Four subsystems are under design that exploit the high flux of direct DT and DD plasma neutrons emanating from a shielded opening in a midplane diagnostic port.
View Article and Find Full Text PDFInertial Confinement Fusion and Magnetic Confinement Fusion (ICF and MCF) follow different paths toward goals that are largely common. In this paper, the claim is made that progress can be accelerated by learning from each other across the two fields. Examples of successful cross-community knowledge transfer are presented that highlight the gains from working together, specifically in the areas of high-resolution x-ray imaging spectroscopy and neutron spectrometry.
View Article and Find Full Text PDFAn overview is given of SPARC's three main x-ray diagnostics, with a focus on the functions they fulfill with respect to tokamak operation. The first is an in-vessel soft x-ray tomography diagnostic, aimed at providing early campaign information on plasma position, MHD activity, and impurity content. The second is an ex-vessel set of hard x-ray scintillators aimed at detecting the presence of runaway electrons, in particular during plasma startup phases.
View Article and Find Full Text PDFTo control and optimize the power of the SPARC tokamak, we require information on the total radiated power of the plasma and its 2D and 3D spatial distribution. The SPARC bolometry diagnostic is being designed and built to measure the radiated power for controlling power balance, investigating the dissipation capabilities of various divertor concepts, and measuring the efficacy of the disruption thermal load mitigation. Proven resistive bolometer sensor technology will be used, with 248 lines of sight integrated into pinhole cameras in 20 different locations.
View Article and Find Full Text PDFSPARC will be outfitted with three systems of x-ray crystal spectrometer arrays. Two of these are designed using cylindrically bent crystals to achieve high spectral-resolution for ion temperature and toroidal velocity measurements via imaging He-like Kr and Ne-like Xe. The last acts as a spectral survey system to monitor Ne-like W and nearby H- and He-like emission from Cr, Fe, Co, Ni, and Cu.
View Article and Find Full Text PDFEdge scanning reflectometry (ESRL) on the SPARC tokamak aims to measure the electron density profile from the far scrape-off layer to the top of the typical H-mode pedestal and provide real-time data for plasma control. ESRL uses a standard frequency-modulated continuous wave technique from 18 to 90 GHz. By implementing both the O-mode and left-hand-cutoff X-mode, it covers densities from ∼4 × 1018 to ∼4 × 1020 m-3 at B0 ∼12 T.
View Article and Find Full Text PDFA new 14 MeV neutron spectrometer utilizing the magnetic proton recoil (MPR) technique is under development for the SPARC tokamak. This instrument measures neutrons by converting them into protons, whose momenta are subsequently analyzed using a series of magnets before detection by an array of scintillators known as the hodoscope. In this work, we explore various solutions for the hodoscope detectors through laboratory tests with radioactive sources and simulations.
View Article and Find Full Text PDFRev Sci Instrum
August 2024
The design of a vacuum ultraviolet spectroscopy system has been performed to monitor and provide feedback for impurity control in SPARC. The spectrometer, covering a wavelength range of 10-2000 Å through a flat-field configuration with diffraction gratings, incorporates five survey lines of sight. This allows for comprehensive impurity analysis across the core and four divertor regions (inner/outer and upper/lower).
View Article and Find Full Text PDFAccurate and real-time monitoring of grapevine freezing tolerance is crucial for the sustainability of the grape industry in cool climate viticultural regions. However, on-site data are limited due to the complexity of measurement. Current prediction models underperform under diverse climate conditions, which limits the large-scale deployment of these methods.
View Article and Find Full Text PDFBackground: Tracheal intubation is the gold standard for airway management in emergency medicine, but more difficult to apply for inexperienced individuals than laryngeal mask airway (LMA).
Objective: The aim of our study was to investigate if inexperienced individuals are able to secure the airway with the help of LMA after a short introduction. A second aim was to evaluate Thiel-fixed specimens against unfixed ones.
Front Sports Act Living
November 2023
The perception of effort is elementary for the self-regulation of exercise intensity in sports. The competence for rating perceived effort (RPE) seems to be related to physical and cognitive development. Children accurately rate perceived effort during incremental exercise tests when loads progressively increase, but it remains unclear how children perform when they participate in sports games, which are characterized by complex tasks with varying intensity profiles.
View Article and Find Full Text PDFA prototype infrared video bolometer (IRVB) was successfully deployed in the Mega Ampere Spherical Tokamak Upgrade (MAST Upgrade or MAST-U), the first deployment of such a diagnostic in a spherical tokamak. The IRVB was designed to study the radiation around the lower x-point, another first in tokamaks, and has the potential to estimate emissivity profiles with spatial resolution beyond what is achievable with resistive bolometry. The system was fully characterized prior to installation on MAST-U, and the results are summarized here.
View Article and Find Full Text PDFApophenia is the tendency to falsely detect meaningful relationships and may indicate susceptibility to more extreme expressions on the psychotic spectrum. This pilot investigated the fragmented ambiguous object task (FAOT), a new measure designed to assess apophenia behaviorally in a sample of adolescents with and without mood disorders using an image recognition task. Our primary hypothesis was that increased image recognition would be associated with PID-5 psychoticism.
View Article and Find Full Text PDFRev Sci Instrum
February 2023
A suite of multi-channel resistive bolometers has been implemented to measure the total radiation from Mega Amp Spherical Tokamak Upgrade plasmas, with cameras covering the core plasma and lower divertor chamber. Data are digitized and processed using novel field-programmable gate array-based electronics, offering improved compactness and new operational capabilities. A synthetic diagnostic has been developed to explore the quality of 2D reconstructions available from the system and to quantify the uncertainty on quantities such as the total radiated power.
View Article and Find Full Text PDFA fiber optic bolometer (FOB) was demonstrated observing a fusion plasma for the first time at the DIII-D tokamak. A FOB uses a fiber optics-based interferometric technique that is designed to have a high sensitivity to temperature changes [75 mK/(W/m) responsivity in high vacuum with 0.38 mK noise level] with a negligible susceptibility to electromagnetic interference (EMI) that can be problematic for resistive bolometers in a tokamak environment.
View Article and Find Full Text PDFEur J Psychotraumatol
August 2022
Unlabelled: Given the prevalence of post-traumatic stress disorder (PTSD), particularly among military personnel, new treatment approaches are needed. One may be virtual relaxation interventions, especially 360-degree nature videos, since studies have demonstrated their relaxation effects for healthy participants. If these relaxation effects can be reproduced in patients with PTSD, they may offer a viable tool to reduce distress and hyperarousal.
View Article and Find Full Text PDFRev Sci Instrum
February 2021
This paper presents techniques for evaluating the radiated power in JET disruptions. Disrupting plasmas are shown to have non-axisymmetric radiation profiles, motivating the re-evaluation of the standard techniques for calculating the total radiated power at JET using bolometry. Four single-channel bolometers at different toroidal locations are exploited to quantify the radiation asymmetry.
View Article and Find Full Text PDFFiber-optic bolometers (FOBs) intended for plasma radiation measurement in magnetically confined fusion have been previously developed using a silicon pillar that functions as both a Fabry-Perot interferometer (FPI) for temperature measurement and an absorber for the radiation. We report an FOB design that can significantly improve the detection sensitivity over earlier designs by engineering the absorber of the FOB. Our design uses the fact that, compared with a silicon pillar, a gold film with the same x-ray absorption thickness will show a much higher temperature rise from a given power density of the radiation.
View Article and Find Full Text PDFActin remodeling is frequently regulated by antagonistic activities driving protrusion and contraction downstream of Rac and Rho small GTPases, respectively. WAVE regulatory complex (WRC), which primarily operates downstream of Rac, plays pivotal roles in neuronal morphogenesis. Recently, two independent studies described de novo mutations in the CYFIP2 subunit of WRC, which caused intellectual disability (ID) in humans.
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