Search

The X-ray spectra of L-shell transitions in Neon-like Xenon ion (Xe44+) have been precisely measured at the Shanghai Electron-Beam Ion Trap using a high-resolution crystal spectrometer. Focusing on the line-intensity ratio of the 3F {2p6-(2p51/23s1/2)J=1} and 3D {2p6-(2p53/23d5/2)J=1} lines (3F/3D), our measurements have achieved remarkable precision improvements over the previous studies. These spectra have been simulated using the collisional-radiative model (CRM) within the Flexible Atomic Code, showing good agreement with the measurements. The previously reported discrepancies, approximately ranging from 10% to 20%, have been significantly reduced in this work to below 1.4% for electron-beam energies exceeding 6 keV and to around 7% for lower energies. Furthermore, our analysis of population fluxes of the involved levels reveals a very high sensitivity of the 3F line to radiation cascades. This suggests that the current CRM, which conventionally excludes interionic population transfer processes, may underestimate the population of the upper level of the 3F line and the cascade-related higher levels, thus explaining the remaining discrepancies. These findings provide a solid foundation for further minimizing these discrepancies and are crucial for understanding the atomic structure and plasma model of these ions. [ABSTRACT FROM AUTHOR]

The X-ray spectra of L-shell transitions in Neon-like Xenon ion (Xe44+) have been precisely measured at the Shanghai Electron-Beam Ion Trap using a high-resolution crystal spectrometer. Focusing on the line-intensity ratio of the 3F {2p6-(2p51/23s1/2)J=1} and 3D {2p6-(2p53/23d5/2)J=1} lines (3F/3D), our measurements have achieved remarkable precision improvements over the previous studies. These spectra have been simulated using the collisional-radiative model (CRM) within the Flexible Atomic Code, showing good agreement with the measurements. The previously reported discrepancies, approximately ranging from 10% to 20%, have been significantly reduced in this work to below 1.4% for electron-beam energies exceeding 6 keV and to around 7% for lower energies. Furthermore, our analysis of population fluxes of the involved levels reveals a very high sensitivity of the 3F line to radiation cascades. This suggests that the current CRM, which conventionally excludes interionic population transfer processes, may underestimate the population of the upper level of the 3F line and the cascade-related higher levels, thus explaining the remaining discrepancies. These findings provide a solid foundation for further minimizing these discrepancies and are crucial for understanding the atomic structure and plasma model of these ions.

A project of a gamma-ray spectrometric system for diagnosing fast particles in the TRT tokamak plasma is described. The organizational concept of gamma spectrometric measurements is proposed. Preliminary results of calculating the intensities of gamma ray lines of hydrogen, deuterium, and deuterium–tritium plasmas are presented, which demonstrate the possibility of obtaining information about the energy and spatial distribution of fast ions with a time resolution of 1–10 s when using a multidetector system. Runaway electrons can be observed by hard X-ray emission from the tokamak plasma in the megaelectronvolt range. [ABSTRACT FROM AUTHOR]

The Silicon Carbide detector (SiC) is an object of research as an alternative to diamond detectors for fast neutron detection and spectrometry where harsh environments are an issue, like in Tokamaks. Since future breeding blankets mock-ups will feature temperatures up to 550 °C, diamond detectors were characterized in the past, finding limitations in their functionality at high temperatures. This paper expands on the previous work by proving the detection of fast neutrons with good detection parameters of a 250 μm-thick 4 H-SiC detector prototype at temperatures up to 250 °C, highlighting the detector's excellent resilience to temperature. The experiment is conducted with instrumentation similar to the one used in the past with diamond detectors, using as source of irradiation the Frascati Neutron Generator (FNG) in ENEA, which is accelerator driven neutron source based on deuterium-tritium (DT) fusion reaction. [ABSTRACT FROM AUTHOR]

Instrumentation used in the diagnostic of signals in fusion experiment needs protection against surges in signal power, which emerges from the electron cyclotron resonance heating (ECRH). In this article, a design methodology for the development of selective single notch waveguide is presented. The design of the notch filter is a circular corrugated waveguide that has been modeled based on the second-order Bragg-resonance condition. The device operation is between 75 and 105 GHz (i.e., $W$ -band), and a single stopband frequency is achieved. The magnitude of stopband transmission is further improved by modifying the corrugation geometry, where selected corrugations are combined periodically inside the waveguide. The proposed design allows the propagation of HE11 mode. Due to the Bragg condition, the LP12 mode is observed at the frequency of stopband resonance, i.e., 94 GHz. The proposed device was fabricated, and the measured transmission coefficient ($S_{21}$) was observed in coherence with the simulated $S_{21}$ profile. The notch filter finds an important application in wideband signal diagnostics of electron cyclotron emission (ECE) and reflectometry in the fusion plasma experiments. [ABSTRACT FROM AUTHOR]

• An E ∥ B NPA has been developed on the HL-3 for the diagnosis of 28 (16)–200 keV H (D). • The ability of the dispersion system was verified on an ion source platform. • Experimental results on HL-3 are consistent with the energy and mass of neutral beam. An E parallel B type neutral particle analyzer (E ∥ B NPA) that simultaneously provides energy and mass resolved measurements of confined fast ions has been developed on the HL-3 tokamak. To verify the operation and modeling of the diagnostic design, the analyzer was validated with H+ and H 2 + beams from an electron cyclotron resonance (ECR) ion source platform with a maximum energy of 50 keV. Results show that it approaches a satisfactory degree of consistency with the simulation results using COMSOL, according to the strike positions of particles hitting the scintillator detector which are registered from the viewing window. The obtained data from the last HL-3 experimental campaign allow us to conclude that the E ∥ B NPA successfully detected the fast neutrals. Furthermore, the observed dependence of counts on detector channels are corresponding to the injection of neutral beam (deuterium, E = 40 keV). Therefore, the measurement capabilities of different energies and mass of fast ions of this E ∥ B NPA are validated. [ABSTRACT FROM AUTHOR]

For microwave reflectometry-based fusion plasma diagnostics, the acquired data is contaminated by the surrounding noise environment, making it difficult to measure the beat frequency accurately. Discrete wavelet and wavelet packet transforms are unsuitable as the former cannot decompose detailed coefficients, and the latter is a time-variant transform. This paper presents a correlation-based Maximal Overlap Discrete Wavelet Packet Transform (MODWPT), which decomposes the signal using different mother wavelet families. The suitable mother wavelet is chosen based on the metrics like signal-to-noise ratio (SNR), peak signal-to-noise ratio (PSNR), mean squared error (MSE), and mean absolute error (MAE). The data used for analysis is the stationary tokamak wall, for which the beat frequency and distance are measured. After rigorous analysis, it is found that sym12 outperforms with the following values 0.0493 (MSE), 0.1736 (MAE), 4.3334(SNR(dB)), 13.0634(PSNR(dB)) respectively. This technique can be extended to plasma scenarios for accurately measuring beat frequency and density profile. • MODWPT analyses fusion-tokamak back wall data. • Correlation-based sub-bands selection after wavelet decomposition for noise removal. • sym12 wavelet is appropriate for the back wall data analysis. • Outcome can be used for accurate density profile measurement in plasma scenarios. [ABSTRACT FROM AUTHOR]

Abstract: The cross section for d+3He elastic scattering has been determined for the angular range 20–180° (CM) for beam energies E d =0.05 to 11MeV through combined use of experimental data, Coulomb scattering and extrapolations. The results are used to study, for instance, how the cross section is affected by nuclear interaction contributions. Implications of these results on the calculation of knock on effects in (3He)D plasmas subjected to RF heating and their manifestations in the spectrum of the d+d fusion neutron emission are discussed. [Copyright &y& Elsevier]

Abstract: Application of reaction-produced -rays to diagnostics of energetic particles in burning plasmas is analyzed. Particularly, we focus on 0.981MeV -rays emitted in the nuclear reaction solely governed in the plasmas by energetic tritons. It is shown that these quanta can serve as a promising tool to diagnose knock-on tritons and -particles confined in burning DT plasmas. Key parameters of the knock-on triton population and the -particle confinement property can be obtained by comparing the experimental -ray yield and spectrum with theoretical slowing-down calculations. Even if the -ray spectral shape cannot be acquired, one can monitor densities of these tritons and -particles at energies of 0.6–1.8MeV and 2.0–3.5MeV, respectively, in a nearly steady-state plasma. The 0.981-MeV photons also would help to display time evolution of the -particle population in experiments of deuterium plasmas with pulsed tritium beam shots. [Copyright &y& Elsevier]

The processes of helium single ionisation and excitation by proton impact are reviewed for the collision energy region relevant to He beam fusion edge plasma diagnostics (proton energy 10 keV). Classical trajectory Monte Carlo (CTMC) calculations have been performed and compared with the existing data. Obtained results for single ionisation are close to available experimental data, while for excitation they are larger by up to a factor of two. For excitation into high quantum numbers, the n−3 scaling law is verified by our CTMC calculations. [Copyright &y& Elsevier]