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The density shoulder represents a universal physical phenomenon that is closely related to the particle and energy transports occurring within the scrape-off layer (SOL) region of tokamak devices. A novel method has been developed to identify the density shoulder through the analysis of the bump structure in the time delay spectra from monostatic microwave reflectometry in EAST tokamak, obviating the need for density profile reconstruction. The density shoulder in EAST is characterized by a number of distinctive features. The density shoulder is mostly situated at a distance of 0–3 cm from the last closed flux surface, with a width of a few centimeters. No significant correlation is observed between its occurrence and the auxiliary heating or the confinement state. In the case of H-mode with quasi-coherent mode (QCM), a significant and positive correlation is observed between the density shoulder amplitude and QCM intensity. In the case of grassy-edge localized mode (ELM)-like H-mode, a density shoulder is also observed during the inter-ELM stage. Furthermore, as supersonic molecular beam injection (SMBI) deposits occur within the range of ρ = 0.9 ∼ 1, the density shoulder is also enhanced during the SMBI fueling process. Moreover, it appears that the neutral pressure has a more pronounced impact on the overall offset of the density profile than the strength of the density shoulder. These results collectively indicate that the outward particle transport from the pedestal to the SOL region plays a crucial role in the evolution of the density shoulder. [ABSTRACT FROM AUTHOR]

Velocity, density, and magnetic fluctuations of the geodesic acoustic mode (GAM) have been measured using the Doppler backscattering system, Faraday-effect polarimeter-interferometer, and external pick-up coils in the Experimental Advanced Superconducting Tokamak. Simultaneous measurements of density and velocity fluctuations at the midplane and top of plasmas demonstrate that m = 1 density fluctuations are quantitatively balanced by the compression of perpendicular flow fluctuations. Furthermore, internal magnetic fluctuations associated with GAM have now been directly measured by laser-based Faraday-effect polarimetry for the first time. Line-averaged magnetic fluctuations (up to 16 Gauss, B ̃ ¯ R , GAM B T ∼ 0.066 %) are significantly larger than those extrapolated from edge coils (a few Gauss) and that magnetic fluctuations increase with β. The observed discrepancy between finite β theory and experimental data indicates the need for further theoretical investigations. [ABSTRACT FROM AUTHOR]

A Faraday-effect radial interferometer–polarimeter is designed for the National Spherical Torus Experiment-Upgrade (NSTX-U) to measure multiscale magnetic and density fluctuations critical to understanding fusion plasma confinement and stability, including those originating from magnetohydrodynamic instabilities, energetic particle-driven modes, and turbulence. The diagnostic will utilize the three-wave technique with 5 MHz bandwidth to simultaneously measure line-integrated magnetic and density fluctuations up to the ion-cyclotron frequency. Probe beams will be launched radially from the low-field side at the NSTX-U midplane, where the measured Faraday fluctuations mainly correspond to radial magnetic fluctuations that directly link to magnetic transport. A correlation technique will be employed to reduce the measurement noise to below 0.01° enabling detection of small amplitude fluctuations. Two toroidally displaced chords with 7° separation will be installed to measure toroidal mode numbers up to n = 25 for mode identification. Solid-state microwave sources operating at 321 μm (935 GHz) will be used to minimize the impact of the Cotton–Mouton effect. [ABSTRACT FROM AUTHOR]

The project of the Visible Spectroscopy diagnostics for the Z eff radial profile measurement and for the divertor visible imaging spectroscopy, designed for the new tokamak DTT (Divertor Tokamak Test), is presented. To deal with the geometrical constraints of DTT and to minimize the diagnostics volume inside the access port, an integrated and compact solution hosting the two systems has been proposed. The Z eff radial profile will be evaluated from the Bremsstrahlung radiation measurement in the visible spectral range, acquiring light along ten Lines of Sight (LoS) in the upper part of the poloidal plane. The plasma emission will be focused on optical fibers, which will carry it to the spectroscopy laboratory. A second equipment, with a single toroidal LoS crossing the plasma centre and laying on the equatorial plane, will measure the average Z eff on a longer path, minimizing the incidental continuum spectrum contaminations by lines/bands emitted from the plasma edge. The divertor imaging system is designed to measure impurity and main gas influxes, to monitor the plasma position and kinetics of impurities, and to follow the plasma detachment evolution. The project aims at obtaining the maximum coverage of the divertor region. The collected light can be shared among different spectrometers and interferential filter devices placed outside the torus hall to easily change their setup. The system is composed of two telescopes, an upper and a lower one, allowing both a perpendicular and a tangential view of the DTT divertor region. This diagnostic offers a unique and compact solution designed to cope the demanding constraints of this next-generation tokamak fusion devices, integrating essential tools for wide-ranging impurity characterization and versatile investigation of divertor physics. [ABSTRACT FROM AUTHOR]

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The capillary wave model of a liquid surface predicts both the X‐ray specular reflection and the diffuse scattering around it. A quantitative method is presented to obtain the X‐ray reflectivity (XRR) from a liquid surface through the diffuse scattering data around the specular reflection measured using a grazing incidence X‐ray off‐specular scattering (GIXOS) geometry at a fixed horizontal offset angle with respect to the plane of incidence. With this approach the entire Qz‐dependent reflectivity profile can be obtained at a single, fixed incident angle. This permits a much faster acquisition of the profile than with conventional reflectometry, where the incident angle must be scanned point by point to obtain a Qz‐dependent profile. The XRR derived from the GIXOS‐measured diffuse scattering, referred to in this paper as pseudo‐reflectivity, provides a larger Qz range compared with the reflectivity measured by conventional reflectometry. Transforming the GIXOS‐measured diffuse scattering profile to pseudo‐XRR opens up the GIXOS method to widely available specular XRR analysis software tools. Here the GIXOS‐derived pseudo‐XRR is compared with the XRR measured by specular reflectometry from two simple vapor–liquid interfaces at different surface tension, and from a hexadecyltrimethylammonium bromide monolayer on a water surface. For the simple liquids, excellent agreement (beyond 11 orders of magnitude in signal) is found between the two methods, supporting the approach of using GIXOS‐measured diffuse scattering to derive reflectivities. Pseudo‐XRR obtained at different horizontal offset angles with respect to the plane of incidence yields indistinguishable results, and this supports the robustness of the GIXOS‐XRR approach. The pseudo‐XRR method can be extended to soft thin films on a liquid surface, and criteria are established for the applicability of the approach. [ABSTRACT FROM AUTHOR]

This study investigates the dielectric properties of conductive biocomposites (CBs), which are integral to the development of advanced materials for flexible electronics and medical devices. A novel method employing Microwave Reflectometry (MR) is introduced, utilizing a miniaturized Vector Network Analyzer (m-VNA) and a dedicated sensing element (SE), to extract the dielectric properties of CBs. The method is grounded in a minimization principle, aligning the measured S 11 reflection scattering parameter with its electromagnetic (EM) simulation, facilitating a refined process for determining the dielectric properties. The experimental setup was meticulously engineered, optimized, and validated using reference dielectric samples (RDSs) with known dielectric properties. The method was then applied to three innovative CBs, resulting in an accurate extrapolation of their dielectric properties. The findings highlight the method's versatility, cost-efficiency, and applicability to ultra-thin and flexible biopolymer films, offering significant potential for advancements in flexible electronics and bio-sensing applications. [ABSTRACT FROM AUTHOR]

Non-equilibrium plasmas at atmospheric pressure are often characterized by optical emission spectroscopy. Despite the simplicity of recording optical emission spectra in plasmas, the determination of spatially resolved plasma properties (e.g., electron temperature) in an efficient way is very challenging. In this study, spatially resolved optical images of a microwave argon plasma jet expanding into the ambient air are recorded over a wide range of wavelengths using a hyperspectral imaging system based on a tunable Bragg-grating imager coupled to a scientific complementary metal–oxide–semiconductor camera. The system's working principle is detailed, along with the necessary post-processing steps. Further analysis of the spatial–spectral data, including the Abel transform used to determine 2D radially resolved spatial mappings, is also presented. Overall, the proposed approach provides unprecedented cartographies of key plasma parameters, such as argon and oxygen line emission intensities, Ar metastable number densities, and argon excitation temperatures. Considering that all these plasma parameters are obtained from measurements performed in a reasonable time, Bragg-grating-based hyperspectral imaging constitutes an advantageous plasma diagnostic technique for detailed analysis of microwave plasma jets used in several applications. [ABSTRACT FROM AUTHOR]

Low-temperature scanning probe microscopes (SPMs) are critical for the study of quantum materials and quantum information science. Due to the rising costs of helium, cryogen-free cryostats have become increasingly desirable. However, they typically suffer from comparatively worse vibrations than cryogen-based systems, necessitating the understanding and mitigation of vibrations for SPM applications. Here we demonstrate the construction of two cryogen-free dilution refrigerator SPMs with minimal modifications to the factory default and we systematically characterize their vibrational performance. We measure the absolute vibrations at the microscope stage with geophones and use both microwave impedance microscopy and a scanning single-electron transistor to independently measure tip-sample vibrations. Additionally, we implement customized filtering and thermal anchoring schemes and characterize the cooling power at the scanning stage and the tip electron temperature. This work serves as a reference to researchers interested in cryogen-free SPMs, as such characterization is not standardized in the literature or available from manufacturers. [ABSTRACT FROM AUTHOR]

Low-pressure plasmas, in particular magnetron sputtering discharges, are increasingly used for the deposition of wideband gap semiconductor nitrides films (e.g., GaN or AlN) considering many benefits they exhibit with respect to conventional chemical vapor deposition techniques. Plasma-based solutions enable the dissociation of N2 molecules into N-atoms under conditions that would not be possible with the thermal process. However, as the dissociation rate remains quite small due to the strong nitrogen triple bond, it is somewhat complicated to determine and correlate the N-atoms density in the gas phase with that of the grown film in low-pressure discharges. Therefore, ns-two-photon absorption laser induced fluorescence (TALIF) has been carried out to determine the absolute density of N-atoms as a function of the pressure (tens of Pa range) in a radio-frequency sputtering plasma reactor used for GaN deposition. The TALIF set-up has been optimized using a monochromator and adequate signal processing to enhance the detection limit, enabling the measurement of N-atoms density as low as 1011 cm−3 at 15 Pa. These measurements have been completed with electron density measurements performed in the same pressure range using microwave interferometry, thus providing quantitative data on both electron and N-atom densities that can be used for fundamental understanding, process optimization, and modeling of magnetron discharge intended for nitride semiconductor deposition. [ABSTRACT FROM AUTHOR]

Microwave imaging has been widely used in stroke diagnosis as a non‐invasive, ionizing radiation‐free imaging method. However, the electromagnetic inverse scattering problems of microwave imaging are nonlinear and ill‐posed. To further improve the accuracy of microwave imaging algorithms to identify and reconstruct stroke regions. A novel Encoder‐Decoder and Modified U‐Net (ED‐MUNET) network for microwave imaging of stroke is proposed. The newly proposed ED‐MUNET method accomplishes the initial imaging from scattered data to stroke images through an encoder–decoder in the first step. In the second step, the feature information of the reconstructed image is extracted through the modified U‐Net network, and the reconstruction from the rough stroke image to the high‐resolution image is realized. The second step avoids black‐box operations and improves image accuracy. ED‐MUNET has fewer artifacts, the relative reconstruction error is less than 0.05, and the reconstructed images are clearer, according to the comparative experiments with other networks. The experimental results showed the superiority of the proposed method for reconstructing stroke images. [ABSTRACT FROM AUTHOR]

This study explores the potential of implementing the focusing properties of a virtual ideal Veselago lens within a standard free-space microwave imaging scenario. To achieve this, the virtual lens is introduced as an inhomogeneous numerical background for the inverse source problem. This numerical Vesealgo lens is incorporated into the incident and scattered field decomposition, resulting in a new data equation that involves the Veselago lens Green's function. In addition to the contrast sources within the object-of-interest, the lens introduces virtual contrast sources along the lens boundaries that depend on the total tangential magnetic field. It is shown that a surface integral contribution that takes into account these surface contrast sources must be added to the collected free-space data before one can invert using the well-conditioned Veselago lens inversion operator. A preliminary investigation of the accuracy to which this surface integral contribution must be computed is performed using additive Gaussian noise. Results show that an error of less than one percent is required to achieve imaging performance similar to utilizing an actual Veselago lens. All results are performed within a 2D simulation environment. [ABSTRACT FROM AUTHOR]

• Integrated approach for multi-scale and multi-resolution diagnostics of wall paintings by the combination of wave-based and optical techniques. • Surface and subsurface investigation for the stratigraphic reconstruction of past intervention and modification. • For the first time, the microwave reflectometry is here proposed in combination with digital holographic speckle pattern interferometry for wall paintings inspection. • Proof of concept of the proposed tool on the wall paintings masterpiece of Masolino, Masaccio and Filippino Lippi in the Brancacci chapel in Firenze. Based on the analysis of the renaissance wall paintings by Masaccio, Masolino, and Filippino Lippi in the Brancacci chapel in Firenze, this paper discusses the use of complementary non-destructive techniques based on microwave and optical methods for the characterization of the structural integrity of the wall paintings and their support in masonry. The selected non-destructive techniques are the InfraRed Thermography (IRT), Ground Penetrating Radar (GPR), Microwave Reflectometry (MWR), and Digital Holographic Speckle Pattern Interferometry (DHSPI). In particular, the paper analyses the in-situ applicability of these techniques for the identification of the sequence of past interventions during centuries (stratigraphy analysis) and decay phenomena and defects, such as out-of-plumb or swelling area/elements, detachments, cracks and voids inside the wall. The results are compared with data obtained by means of consolidated techniques and methods, such as the Photogrammetry (performed by Structure from Motion method) and knocking test. The last one is normally used by restorers and conservators to recognize the presence of detachments. The proposed diagnostic strategy provides a survey from large scale by means of imaging techniques, to small scale increasing the spatial resolution thanks to the scanning of the surface by means of spot techniques. Therefore, the macroscopic survey of wall paintings was carried out using photogrammetry, in order to also provide metric information, to quantify the sizing out-of-plumb and swelling of the masonry or to locate of cracks, and followed by IRT. This preliminary morphometric survey was, supplemented by GPR, MWR and DHSPI for improve the results of the investigation. By combining these three techniques it was possible to inspect the entire thickness of the masonry (60-70 cm) with resolutions ranging from a few millimetres up to several centimetres. The combination of microwave-based and optical-based methods proved to be a valuable addition to routine methods for the holistic masonry diagnosis. Standard practice based on visual inspection and knocking test can be significantly improved and objectified by the proposed full-field, multi-sensor, multi-resolution approach. [ABSTRACT FROM AUTHOR]

Particulate matter air pollution in the form of ultrafine dust is a growing global concern. In this Letter, we will use a nanodusty Ar/HMDSO plasma as a model system for a heavily contaminated gas and we present the development of a technique for real-time in situ measurements of the dust particle size. The method is based on laser-induced photodetachment of bound electrons from the surface of dust particles. These photo-released electrons are measured as an increase in the free electron density of the plasma using microwave cavity resonance spectroscopy. We show that instead of reconstructing the entire resonance profile, the temporal response of a single microwave frequency was enough to perform the measurements. More specifically, the decay timescale of the cavity response can be interpreted as the re-charging timescale of the dust particles. Then, using a stochastic model, this timescale can be modeled, which eventually retrieves the dust particle size. We found good agreement between the predicted dust particle size and the average dust particle size obtained from ex situ scanning electron microscopy measurements. This method allows for the real-time monitoring of the dust particle size and a controlled production of nanometer-scale dust particles, which gives opportunities both for fundamental dusty plasma physics and models, as well as for applications in monitoring ultrafine dust air pollution. [ABSTRACT FROM AUTHOR]

Continuous measurement of pressure is vital in many fields of industry, medicine, and science. Of particular interest is the ability to measure pressure in a noninvasive and contact-free manner. This work presents the potential of oblique incident reflectometry (OIR) to monitor variation in pressure via the reduced scattering parameter (μ s ′). Pressure deforms the geometry of the medium and causes distortion of its internal structure and the spatial distribution of optical properties. Light scattering is related to the morphology (size, density, distribution, etc.) and refractive index distributions of the medium, and applied pressure will influence directly these parameters. Therefore, we assume that pressure can be quantitatively assessed through monitoring the reduced scattering coefficient. For this purpose, the technique of OIR to evaluate the scattering parameter during pressure variations was utilized. OIR is a simple noninvasive and contact-free imaging technique able to quantify both absorption and scattering properties of a sample. In our setup, the medium is illuminated obliquely by a narrow laser beam, and the diffuse reflectance light is captured by a CCD camera. In offline processing, the shift (δ) of the diffuse light center from the incident point is mathematically analyzed and μ s ′ coefficient (μ s ′ ∼ δ − 1) is extracted. We present here confirmation of the validity of this assumption through results of a series of experiments performed on turbid liquid and artery occlusion of a human subject under different pressure levels. Thus, μ s ′ has the potential to serve as a good indicator for the monitoring of pressure. [ABSTRACT FROM AUTHOR]

We present two methods for improved calibration of multi-point electron density measurements from incoherent scatter radars (ISR). They are based on the well-established Flatfield correction method used in imaging and photography, where we exploit the analogy between independent measurements in separate pixels in one image sensor and multi-beam radar measurements. Applying these correction methods adds to the current efforts of estimating the magic constant or system constant made for the calibration of multi-point radars, increasing data quality and usability by correcting for variable, unaccounted, and unpredictable variations in system gain. This second-level calibration is especially valuable for studies of plasma patches, irregularities, turbulence, and other research where inter-beam changes and fluctuations of electron density are of interest. The methods are strictly based on electron density data measured by the individual radar and require no external input. This is of particular interest when independent measurements of electron densities for calibration are available only in one pointing direction or not at all. A correction factor is estimated in both methods, which is subsequently used to scale the electron density measurements of a multi-beam ISR experiment run on a phased array radar such as RISR-N, RISR-C, PFISR, or the future EISCAT3D radar. This procedure could improve overall data quality if used as part of the data-processing chain for multi-beam ISRs, both for existing data and for future experiments on new multi-beam radars. [ABSTRACT FROM AUTHOR]

An improved prototype of the large-aperture, high-resolution spectrometer−polychromator (the so-called high-etendue spectrometer, HES) has been designed for spectroscopy diagnostics of plasma, in particular, for the Charge-eXchange Recombination Spectroscopy (CXRS) diagnostics at the ITER facility. Ion temperature profiles, poloidal and toroidal plasma rotation velocities, and low-Z impurity densities can be measured using the CXRS technique. The HES is equipped with novel, high-efficiency compact sCMOS cameras with low noise level, wide dynamic range, high quantum efficiency, and almost 100% working cycle. The HES is based on three transmission holographic gratings, which allow its simultaneous operation in three spectral bands: 468 ± 5, 529 ± 5, and 656 ± 6 nm. The main performance characteristics of the cameras, transmission gratings, and the spectrometer as a unit have been measured. It has been established that the characteristics of the developed HES satisfy the requirements for the spectroscopic equipment intended for measurements of the ITER CXRS diagnostic system. [ABSTRACT FROM AUTHOR]

The development of synthetic diagnostics for passive plasma spectroscopy systems of the T-15MD tokamak is started using the Cherab software library for modeling fusion plasma spectroscopy. The calculation of signals in the visible wavelength range is performed with the Raysect code using the ray tracing technique, taking into account the reflection of light from the surfaces of the first wall specified as a full CAD model. The results of measuring the characteristics of light reflection by samples of the T-15MD graphite first wall before and after plasma exposure are used. The parameters of the model functions of graphite reflectivity are chosen by fitting the measurements. The results of edge plasma modeling by the SOLPS code are used to calculate the intensity of the spectral line Hα and the fraction of reflected light in the observed intensity depending on the geometry of the line of sight. It is shown that, during radial observation of the scrape-off layer plasma, the reflected light fraction in the observed intensity does not exceed 50%, and after a long-term exposure of the wall to the plasma, it should decrease to 10–20%. For lines of sight of diagnostics that measure the effective plasma charge profile, the bremsstrahlung and photorecombination radiation spectra are calculated on the basis of the combined data of modeling by the ASTRA and SOLPS codes. It is shown that only the lines of sight observing the peripheral plasma are subject to a significant influence of reflected light, where the intensity of bremsstrahlung is minimal. As in the case of Hα radiation, a long-term exposure of the wall to the plasma is expected to reduce the reflected light fraction in the observed intensity by a factor of 3–4. [ABSTRACT FROM AUTHOR]

We present the first Thomson scattering (TS) measurements of electron temperature in the lower divertor of the Globus-M2 tokamak. The divertor TS diagnostics is designed for local measurements of the Te(z, t) in the range of 1–100 eV and ne(z, t) in the range of m–3. Parameters of the probing Nd:YAG laser are as follows 1064 nm/2 J/100 Hz/3 ns. The probing chord is launched vertically at R = 24 cm and covers areas of the inner leg, vicinity of separatrix and private flux region. Along probing chord of 110 mm, 9 spatial points were realized. Advanced filter polychromators were used to analyze Thomson scattering spectra. [ABSTRACT FROM AUTHOR]

The present work was designed to investigate the effect of maceration, ultra-sound, and microwave-assisted extraction on free, esterified, and bound phenolics of Tulaipanji rice (Oryza sativa L.) flour. Antioxidant activity was measured by DPPH, ABTS, SOD, and reducing power assays. HPTLC analysis was performed for identification and quantification of phenolics in different extracts. Total phenolic (TPC) and total flavonoid contents (TFC) were found significantly high (p < 0.05) in microwave-assisted extraction of bound phenolics compared with other methods. Microwave-assisted extracts showed highest DPPH radicals, ABTS radicals, SOD, and reducing power activity. Further, Pearson's correlation study exhibited a significant positive correlation within % yield, TPC, and TFC. Significant negative correlation was found within % yield, TPC, TFC, and antioxidant activity. The study found that extractive value, antioxidant activity, and phenolic contents varied with the extraction methods. Microwave-assisted extraction technique showed the best performance for extraction as compared to other methods. [ABSTRACT FROM AUTHOR]

Despite recent improvements in microscopy, it is still difficult to apply superresolution microscopy for deep imaging due to the deterioration of light convergence properties in thick specimens. As a strategy to avoid such optical limitations for deep super-resolution imaging, we focused on super-resolution radial fluctuation (SRRF), a super-resolution technique based on image analysis. In this study, we applied SRRF to two-photon microscopy (2P-SRRF) and characterized its spatial resolution, suitability for deep observation, and morphological reproducibility in real brain tissue. By the comparison with structured illumination microscopy (SIM), it was confirmed that 2P-SRRF exhibited two-point resolution and morphological reproducibility comparable to that of SIM. The improvement in spatial resolution was also demonstrated at depths of more than several hundred micrometers in a brain-mimetic environment. After optimizing SRRF processing parameters, we successfully demonstrated in vivo high-resolution imaging of the fifth layer of the cerebral cortex using 2P-SRRF. This is the first report on the application of SRRF to in vivo two-photon imaging. This method can be easily applied to existing two-photon microscopes and can expand the visualization range of super-resolution imaging studies. [ABSTRACT FROM AUTHOR]

Microwave imaging is one of the rapidly developing frontier disciplines in the field of modern medical imaging. The development of microwave imaging algorithms for reconstructing stroke images is discussed in this paper. Compared with traditional stroke detection and diagnosis techniques, microwave imaging has the advantages of low price and no ionizing radiation hazards. The research hotspots of microwave imaging algorithms in the field of stroke are mainly reflected in the design and improvement of microwave tomography, radar imaging, and deep learning imaging. However, the current research lacks the analysis and combing of microwave imaging algorithms. In this paper, the development of common microwave imaging algorithms is reviewed. The concept, research status, current research hotspots and difficulties, and future development trends of microwave imaging algorithms are systematically expounded. The microwave antenna is used to collect scattered signals, and a series of microwave imaging algorithms are used to reconstruct the stroke image. The classification diagram and flow chart of the algorithms are shown in this Figure. (The classification diagram and flow chart are based on the microwave imaging algorithms.) [ABSTRACT FROM AUTHOR]

The low-frequency fluctuations of the atomic density within the cell can induce the longterm drift of the K-Rb-21Ne spin-exchange relaxation-free (SERF) co-magnetometer output, such that the accurate measurement of in situ atomic density is of great significance for improving the performance of co-magnetometer. In this paper, the complex refractive index model of the spin ensembles under the hybrid optical pumping condition is established first, according to which the relation between atomic density and its complex refractive index is revealed and an optical heterodyne-based scheme for atomic density detection is proposed. The dependence of the atomic density on the demodulated phase signal from the optical heterodyne-based scheme is provided by numerical simulations. After that, a dual acousto-optics frequency shifter (AOFS)-based optical heterodyne interferometry is constructed with a noise level below 1 mrad/ Hz for frequencies > 1 Hz, and a compact SERF co-magnetometer is implemented as the testing medium, by which the atomic density detection with resolution of 0.40 K @ 473 K is reached and the experimental results agree well with theoretical simulations. Moreover, the detection scheme proposed in this paper has the properties of high detection sensitivity and immunity to laser power fluctuation, which are also proved experimentally. [ABSTRACT FROM AUTHOR]

Antipodal Vivaldi antennas hold significant importance in medical applications, particularly in the field of microwave imaging, due to their wideband characteristics and efficient radiation properties. These antennas have shown promising results, enabling precise tumor localization and characterization in breast cancer detection, thus facilitating early diagnosis and improving patient outcomes (vers la conclusion). This paper presents the development of a prototype antipodal antenna through a meticulous process that involved using an electromagnetic solver that utilizes the Finite Element Method (FEM) for conceptualization and subsequent realization of the proposed antenna. Rigorous testing in our laboratory has demonstrated auspicious and concrete results, showcasing the antenna's exceptional performance in terms of radiation patterns and efficacy in the Ultra-Wide Band (UWB) frequency region. Furthermore, we found a strong correlation between the simulated and measured values of the reflection coefficients (S11), validating the accuracy and reliability of our design approach. These findings mark substantial progress in our pursuit of developing a low-cost imaging system for early breast cancer detection. [ABSTRACT FROM AUTHOR]

Microwave impedance microscopy (MIM) is a near-field imaging technique that has been used to visualize the local conductivity of materials with nanoscale resolution across the GHz regime. In recent years, MIM has shown great promise for the investigation of topological states of matter, correlated electronic states, and emergent phenomena in quantum materials. To explore these low-energy phenomena, many of which are only detectable in the milliKelvin regime, we have developed a novel low-temperature MIM incorporated into a dilution refrigerator. This setup, which consists of a tuning-fork-based atomic force microscope with microwave reflectometry capabilities, is capable of reaching temperatures down to 70 mK during imaging and magnetic fields up to 9 T. To test the performance of this microscope, we demonstrate microwave imaging of the conductivity contrast between graphite and silicon dioxide at cryogenic temperatures and discuss the resolution and noise observed in these results. We extend this methodology to visualize edge conduction in Dirac semi-metal cadmium arsenide in the quantum Hall regime. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel method for obtaining wideband spectral information of the target in microwave imaging systems by using broadband frequency reconfigurable printed transceivers. The proposed transceiver is composed of two embedded stacked microstrip antenna configurations operating in C-band (5.5–8.5 GHz) and X-band (8.5–11.5 GHz) with each having 3 GHz bandwidth. The transceiver switches between the two configurations (and thus frequency bands) using PIN diodes and collects response of the antenna in the presence of the target, in both the operating bands. This information is then combined to obtain wideband spectral information of the target from 5.5 to 11.5 GHz to achieve improved image reconstruction. The proposed reconfigurable transceiver has advantage over traditional broadband transceivers (those have slots/meandering at ground plane to achieve wideband response) that it has unidirectional radiation patterns throughout its band of operation. Hence the imaging system is implemented without the absorbers. This keeps the system compact and inconspicuous when installed for security applications. Here, a bistatic system is employed with two-dimensional target scanning performed in a real outdoor environment. [ABSTRACT FROM AUTHOR]

The microwave imaging system for breast tumor/cancer detection requires high sensitivity to detect abnormal tissue that has little contrast in high-density breasts. This paper proposes a qualitative microwave imaging system simulation based on inverse scattering using the sensitivity-maps method. This method utilizes two measurement types for system calibration: a reference object as a scatterer-free background and a calibration object to obtain the system’s impulse response. The object under test (OUT) consists of an object with low dielectric contrast and a phantom with multiple low dielectric contrasts (multi-contrast). Reconstruction is carried out on three types of S-parameter measurement data, namely S11, S21, and a combination of both. S-parameters are measured at several frequencies, which are 3, 10, 14, 15, 16, 20 GHz, and the combination of all those frequencies (multifrequency). Reconstructed images show that the system is capable of reconstructing dielectric objects accurately. Quantitatively, the results show that the multifrequency S21 measurement yields the best image quality with relative root mean squared error (RRMSE) values of 0.1272 and structural similarity index (SSIM) of 0.9076. The designed imaging system also successfully reconstructs multi-contrast phantom accurately with RRMSE of 0.1434 and SSIM of 0.4609. [ABSTRACT FROM AUTHOR]

Skin cancer is one of the most commonly diffused cancers in the world and its incidence rates have constantly increased in recent years. At the current state of the art, there is a lack of objective, quick and non-invasive methods for diagnosing this condition; this, combined with hospital crowding, may lead to late diagnosis. Starting from these considerations, this paper addresses the implementation of a microwave reflectometry based-system that can be used as a non-invasive method for the in-vivo diagnosis and early detection of biological abnormalities, such as skin cancer. This system relies on the dielectric contrasts existing between normal and anomalous skin tissues at microwave frequencies (in a frequency range up to 3 GHz). In particular, a truncated open-ended coaxial probe was designed, manufactured and tested to sense (in combination with a miniaturized Vector Network Analyzer) the variations of skin dielectric properties in a group of volunteer patients. The specific data processing demonstrated the suitability of the system for discriminating malignant and benign lesions from healthy skin, ensuring simultaneously effectiveness, low cost, compactness, comfortability, and high sensitivity.

A clear visualization of the physical processes of spatially confined ns laser induced atmospheric air plasma within a rectangular glass cavity using optical imaging is presented. The occurrence of various processes starting from the early plasma and shock wave expansion dynamics to shock reflection at the cavity boundaries and compression of the plasma due to reflected shockwaves is studied using defocused shadowgraphy and self-emission imaging techniques. Experimentally, we evidenced that the counter propagating reflected primary shockwaves interact with the expanding plasma generating a secondary shockwave which compresses the plasma core, modifying the plasma morphology resulting in enhanced plasma parameters. The numerical simulations performed via the two-dimensional hydrodynamic (2D-HD) FLASH codes, revealed that the number density increases up to a maximum of 3.6 times compared to the unconfined plasma. The input laser pulse energy and the aspect ratio of the cavity is observed to play a dominant role in the confinement and compression of the plasma. [ABSTRACT FROM AUTHOR]

Glass fiber-reinforced polymer (GFRP) is widely used in engineering fields involving aerospace, energy, transportation, etc. If internal buried defects occur due to hostile environments during fabrication and practical service, the structural integrity and safety of GFRP structures would be severely undermined. Therefore, it is indispensable to carry out effective quantitative nondestructive testing (NDT) of internal defects buried within GFRP structures. Along with the development of composite materials, microwave NDT is promising in non-intrusive inspection of defects in GFRPs. In this paper, quantitative screening of the subsurface impact damage and air void in a unidirectional GFRP via microwave reflectometry was intensively investigated. The influence of the microwave polarization direction with respect to the GFRP fiber direction on the reflection coefficient was investigated by using the equivalent relative permittivity calculated with theoretical analysis. Following this, a microwave NDT system was built up for further investigation regarding the imaging and quantitative evaluation of buried defects in GFRPs. A direct-wave suppression method based on singular-value decomposition was proposed to obtain high-quality defect images. The defect in-plane area was subsequently assessed via a proposed defect-edge identification method. The simulation and experimental results revealed that (1) the testing sensitivity to buried defects was the highest when the electric-field polarization direction is parallel to the GFRP fiber direction; and (2) the averaged evaluation accuracy regarding the in-plane area of the buried defect reached approximately 90% by applying the microwave reflectometry together with the proposed processing methods. [ABSTRACT FROM AUTHOR]

The European Shock Tube for High-Enthalpy Research is a new state-of-the-art facility, tailored for the reproduction of spacecraft planetary entries in support of future European exploration missions, developed by an international consortium led by Instituto de Plasmas e Fusão Nuclear and funded by the European Space Agency. Deployed state-of-the-art diagnostics include vacuum-ultraviolet to ultraviolet, visible, and mid-infrared optical spectroscopy setups, and a microwave interferometry setup. This work examines the specifications and requirements for high-speed flow measurements, and discusses the design choices for the main diagnostics. The spectroscopy setup covers a spectral window between 120 and 5000 nm, and the microwave interferometer can measure electron densities up to 1.5 × 1020 electrons/m3. The main design drivers and technological choices derived from the requirements are discussed in detail herein. [ABSTRACT FROM AUTHOR]

We developed a miniaturized coplanar Vivaldi antenna (M‐CPVA) for microwave imaging applications. First, a conventional coplanar Vivaldi antenna (CPVA) was designed. Then, the M‐CPVA was developed by properly cropping the exponential flares. The impedance bandwidth and near‐field electric field distribution of the M‐CPVA were improved as compared to the conventional CPVA. In particular, the designed M‐CPVA was 58.6 × 92 × 1.6 mm3 in size and operated from 1 to 7.5 GHz, corresponding to a fractional bandwidth of 152%. Last, the produced M‐CPVA was tested in a microwave imaging system for continuous monitoring of brain strokes. The stability and accuracy of the imaging results imply that the proposed antenna could be useful for microwave brain stroke monitoring applications. [ABSTRACT FROM AUTHOR]

Two camera systems are installed on the DIII-D tokamak at the toroidal positions of 90° (90° system) and 225° (225° system), respectively. The cameras have two types of relay optics, namely, a coherent optical fiber bundle and a periscope system. The periscope system provides absolute intensity calibration stability while sacrificing resolution (10 lp/mm), while the fiber system provides high resolution (16 lp/mm) while sacrificing calibration stability. The periscope is available only for the 90° system. The optics of the 225° system were designed for view stability, repeatability, and easy maintenance. The cameras are located inside optimized neutron, x ray and magnetic shielding in order to reduce electronics damage, reboots, and magnetic and neutron interference, increasing the overall system reliability. An automated filter wheel, providing remote filter change, allows for remote wavelength selection. A software suite automates camera acquisition and data storage, allowing for remote operation and reduced operator involvement. System metadata is used to streamline the data analysis workflow, particularly for intensity calibration. The spatial calibration uses multiple observable wall features, resulting in a reconstruction accuracy ≤2 cm. [ABSTRACT FROM AUTHOR]

Providing energy from fusion and finding ways to scale up the fusion process to commercial proportions in an efficient, economical, and environmentally benign way is one of the grand challenges for engineering. Controlling the burning plasma in real-time is one of the critical issues that need to be addressed. Plasma Position Reflectometry (PPR) is expected to have an important role in next-generation fusion machines, such as DEMO, as a diagnostic to monitor the position and shape of the plasma continuously, complementing magnetic diagnostics. The reflectometry diagnostic uses radar science methods in the microwave and millimetre wave frequency ranges and is envisaged to measure the radial edge density profile at several poloidal angles providing data for the feedback control of the plasma position and shape. While significant steps have already been given to accomplish that goal, with proof of concept tested first in ASDEX-Upgrade and afterward in COMPASS, important, ground-breaking work is still ongoing. The Divertor Test Tokamak (DTT) facility presents itself as the appropriate future fusion device to implement, develop, and test a PPR system, thus contributing to building a knowledge database in plasma position reflectometry required for its application in DEMO. At DEMO, the PPR diagnostic's in-vessel antennas and waveguides, as well as the magnetic diagnostics, may be exposed to neutron irradiation fluences 5 to 50 times greater than those experienced by ITER. In the event of failure of either the magnetic or microwave diagnostics, the equilibrium control of the DEMO plasma may be jeopardized. It is, therefore, imperative to ensure that these systems are designed in such a way that they can be replaced if necessary. To perform reflectometry measurements at the 16 envisaged poloidal locations in DEMO, plasma-facing antennas and waveguides are needed to route the microwaves between the plasma through the DEMO upper ports (UPs) to the diagnostic hall. The main integration approach for this diagnostic is to incorporate these groups of antennas and waveguides into a diagnostics slim cassette (DSC), which is a dedicated complete poloidal segment specifically designed to be integrated with the water-cooled lithium lead (WCLL) breeding blanket system. This contribution presents the multiple engineering and physics challenges addressed while designing reflectometry diagnostics using radio science techniques. Namely, short-range dedicated radars for plasma position and shape control in future fusion experiments, the advances enabled by the designs for ITER and DEMO, and the future perspectives. One key development is in electronics, aiming at an advanced compact coherent fast frequency sweeping RF back-end [23–100 GHz in few μs] that is being developed at IPFN-IST using commercial Monolithic Microwave Integrated Circuits (MMIC). The compactness of this back-end design is crucial for the successful integration of many measurement channels in the reduced space available in future fusion machines. Prototype tests of these devices are foreseen to be performed in current nuclear fusion machines. [ABSTRACT FROM AUTHOR]

A novel spectroscopy diagnostic for measuring internal magnetic fields in high temperature magnetized plasmas has been developed. It involves spectrally resolving the Balmer-α (656 nm) neutral beam radiation split by the motional Stark effect with a spatial heterodyne spectrometer (SHS). The unique combination of high optical throughput (3.7 mm2sr) and spectral resolution (δλ ∼ 0.1 nm) allows these measurements to be made with time resolution ≪1 ms. The high throughput is effectively utilized by incorporating a novel geometric Doppler broadening compensation technique in the spectrometer. The technique significantly reduces the spectral resolution penalty inherent to using large area, high-throughput optics while still collecting the large photon flux provided by such optics. In this work, fluxes of order 1010 s−1 support the measurement of deviations of < 5 mT (ΔλStark ∼ 10−4 nm) in the local magnetic field with 50 µs time resolution. Example high time resolution measurements of the pedestal magnetic field throughout the ELM cycle of a DIII-D tokamak plasma are presented. Local magnetic field measurements give access to the dynamics of the edge current density, which is essential to understanding stability limits, edge localized mode generation and suppression, and predicting performance of H-mode tokamaks. [ABSTRACT FROM AUTHOR]

Automated brain tumor segmentation from reconstructed microwave (RMW) brain images and image classification is essential for the investigation and monitoring of the progression of brain disease. The manual detection, classification, and segmentation of tumors are extremely time-consuming but crucial tasks due to the tumor's pattern. In this paper, we propose a new lightweight segmentation model called MicrowaveSegNet (MSegNet), which segments the brain tumor, and a new classifier called the BrainImageNet (BINet) model to classify the RMW images. Initially, three hundred (300) RMW brain image samples were obtained from our sensors-based microwave brain imaging (SMBI) system to create an original dataset. Then, image preprocessing and augmentation techniques were applied to make 6000 training images per fold for a 5-fold cross-validation. Later, the MSegNet and BINet were compared to state-of-the-art segmentation and classification models to verify their performance. The MSegNet has achieved an Intersection-over-Union (IoU) and Dice score of 86.92% and 93.10%, respectively, for tumor segmentation. The BINet has achieved an accuracy, precision, recall, F1-score, and specificity of 89.33%, 88.74%, 88.67%, 88.61%, and 94.33%, respectively, for three-class classification using raw RMW images, whereas it achieved 98.33%, 98.35%, 98.33%, 98.33%, and 99.17%, respectively, for segmented RMW images. Therefore, the proposed cascaded model can be used in the SMBI system. [ABSTRACT FROM AUTHOR]

The impact of sample preparation on bitumen content measurement using LIBS was investigated by collecting spectra from wet and dry tailings. A multivariate data analysis model was developed using optimal wavelength selection for bitumen content classification and prediction in tailings. Wet tailings can be classified into three classes (low, medium, and high bitumen) with 12.1 % error, while dry tailings have a classification error of 6.1 %. Quantitative analysis showed a bitumen content prediction error of 4.7 % for wet tailings and 8.9 % for dry tailings. Wet tailings showed a 1.8–2.5 times improvement in the limit of detection range compared to dry tailings. Plasma density and crater size measurements revealed that plasma density fluctuation was 2.7 times lower in wet tailings due to consistent crater formation from laser-tailings interaction. The lower plasma density fluctuation indicates a stable mass ablation for wet samples, which is attributed as the primary reason for significant LIBS performance improvement on wet tailings. [Display omitted] • Optimization of multivariate calibration model for improved prediction accuracy of the bitumen measurement in using LIBS. • Bitumen measurement accuracy significantly improved in wet tailings compared to dry tailings. • Plasma density and laser-produced craters are substantially consistent for wet tailings. • Use of compact laser and developed calibration model are promising for the future advancement of portable LIBS. [ABSTRACT FROM AUTHOR]

In this work, a resolution improvement strategy has been presented for microwave tomography imaging in the dense and heterogeneous breasts. While improving the spatial resolution by reducing the size of pixels, the resultant image will be affected by spatial oscillation, and it will also lack to differentiate the dielectric values of low contrast tissue regions which are the unavoidable problems in the microwave tomography dense breast imaging. These difficulties are addressed as discrete ill‐posed and ill‐condition problems. In this paper, Enriched Conjugate Gradient Least Square (ECGLS) regularization method has been proposed and it is associated with the Distorted Born Iterative Method (DBIM) to improve the quality of high‐resolution images of heterogeneous and dense type breasts. The Proposed‐ECGLS (PECGLS) method introduces the span of enriched subspace with external penalization value to resolve the discrete ill‐posed problem. The Gram‐Schmidt factorization (or QR factorization) based step length and the external penalization value control the spatial oscillations and resolve the ill‐condition problem with quick convergence. The performance of the Proposed‐ECGLS method has been tested on heterogeneous and dense breast phantoms for synthetically embedded malignant along with differences in permittivity value of +8% to +10% in the fibrogland tissues. The results from the simulation studies depict that the Proposed‐ECGLS has achieved up to 0.8276 of structural similarity in different level discretization error and it is better than the existing methods such as ECGLS and standard CGLS. This high‐resolution microwave tomography imaging method will be helpful in malignant detection and fibroadenoma diagnosis in dense type breasts. [ABSTRACT FROM AUTHOR]

The production of broadband, terawatt terahertz (THz) pulses has been demonstrated by irradiating relativistic lasers on solid targets. However, the generation of extremely powerful, narrow-band and frequency-tunable THz pulses remains a challenge. Here, we present a novel approach for such THz pulses, in which a plasma wiggler is elaborated by a table-top laser and a near-critical density plasma. In such a wiggler, the laser-accelerated electrons emit THz radiations with a period closely related to the plasma thickness. The theoretical model and numerical simulations predict that a THz pulse with a laser--THz energy conversion of over 2.0%, an ultra-strong field exceeding 80 GV/m, a divergence angle of approximately 20° and a center frequency tunable from 4.4 to 1.5 THz can be generated from a laser of 430 mJ. Furthermore, we demonstrate that this method can work across a wide range of laser and plasma parameters, offering potential for future applications with extremely powerful THz pulses. [ABSTRACT FROM AUTHOR]

In a typical laboratory nanodusty plasma, nanometer-sized solid dust particles can be generated from the polymerization of reactive plasma species. The interplay between the plasma and the dust gives rise to behavior that is vastly different from that of pristine plasmas. Two of the key parameters in nanodusty plasma physics are, among other things, the dust particle size and the dust density. In this work, we introduce a novel method for the determination of these two quantities from the measurement of the free electron density using microwave cavity resonance spectroscopy and laser light extinction measurements. When comparing these two measurements to theory, one can determine the best-fitting dust particle size and dust density. Generally, cyclic behavior of the dust particle size and dust density was observed, of which the trends were relatively insensitive to varying the most stringent input assumptions. Finally, this method has been used to explore the behavior of the dust particle size and dust density for varying plasma powers. [ABSTRACT FROM AUTHOR]

This paper presents the design, simulation and experimental validation of a gradient-index (GRIN) metasurface lens operating at 8 GHz for microwave imaging applications. The unit cell of the metasurface consists of an electric-LC (ELC) resonator. The effective refractive index of the metasurface is controlled by varying the capacitive gap at the center of the unit cell. This allows the design of a gradient index surface. A one-dimensional gradient index lens is designed and tested at first to describe the operational principle of such lenses. The design methodology is extended to a 2D gradient index lens for its potential application as a microwave imaging device. The metasurface lenses are designed and analyzed using full-wave finite element (FEM) solver. The proposed 2D lens has an aperture of size 119 mm (3.17λ) × 119 mm (3.17λ) and thickness of only 0.6 mm (0.016λ). Horn antenna is used as source of plane waves incident on the lens to evaluate the focusing performance. Field distributions of the theoretical designs and fabricated lenses are analyzed and are shown to be in good agreement. A microwave nondestructive evaluation (NDE) experiment is performed with the 2D prototype lens to image a machined groove in a Teflon sample placed at the focal plane of the lens. [ABSTRACT FROM AUTHOR]

A novel Motional Stark Effect spectroscopy system has been designed for application at the DIII-D tokamak. The system is optimized for studies of the poloidal and toroidal magnetic field in the plasma pedestal region with frame rates of up to 10 kHz. Light from an existing high-photon-throughput collection lens is analyzed using four single-channel f/2.8 Czerny–Turner spectrometers that use custom-made lens systems instead of mirrors. Each spectrometer has two separate outgoing legs and is operated in a positive grating order, which allows for simultaneous observations of D-alpha and D-beta spectra. Forward modeling using the code FIDASIM shows a radial resolution of the system close to 0.6 cm and sufficiently good spectral resolution when masking the high throughput light collection lens in the horizontal direction to avoid overly strong Doppler broadening of beam emission lines. Moreover, a detailed sensitivity study considering realistic levels of readout and photon noise shows that the poloidal and toroidal magnetic field strengths can be inferred with an uncertainty of less than 1%, which will allow the inference of changes of the plasma current during transient events. [ABSTRACT FROM AUTHOR]

A preliminary system for microwave thorax imaging is designed and experiments are conducted. A compact low-profile symmetrical dipole antenna operating at 915 MHz is designed for the system. An acrylic rectangular box is fabricated as the experiment phantom to mimic an ordinary human thorax. Graduated cylinders with different diameters are used as imaging targets. During measurement, each antenna acts in turn as a transmitter and other antennas act as the receivers. One-step supervised descent method (SDM) is adopted as the imaging algorithm. Results under different scenarios indicate that structural information can be reconstructed with the one-step SDM. This study verifies the feasibility of microwave thorax imaging. [ABSTRACT FROM AUTHOR]

Soil monitoring is a key topic from several perspectives, such as moisture level control for irrigation management and anti-contamination purposes. Monitoring the latter is becoming even more important due to increasing environmental pollution. As a direct consequence, there is a strong demand for innovative monitoring systems that are low cost, provide for quasi-real time and in situ monitoring, high sensitivity, and adequate accuracy. Starting from these considerations, this paper addresses the implementation of a microwave reflectometry based-system utilizing a customized bifilar probe and a miniaturized Vector Network Analyzer (m-VNA). The main objective is to relate frequency-domain (FD) measurements to the features of interest, such as the water content and/or the percentage of some polluting substances, through an innovative automatable procedure to retrieve the Debye dielectric parameters of the soil under different conditions. The results from this study confirm the potential of microwave reflectometry for moisture monitoring and contamination detection. [ABSTRACT FROM AUTHOR]

This work aims to represent the physical properties of a sample of infrared-bright dust-obscured galaxies (DOGs) studied by Suleiman et al. (2022) by fitting the spectral energy distributions (SEDs). Twenty-eight DOGs were examined at redshifts 0.47 ≤ z ≤ 1.63 discovered by combining images of the Subaru Hyper Suprime-Cam (HSC) survey, VISTA Kilo-degree Infrared Galaxy (VIKING) survey, and the Wide-field Infrared Survey Explorer (WISE) all-sky survey, and detected at Herschel Spectral and Photometric Imaging Receiver (SPIRE) bands. The results show a correlation between the star formation rate (SFR) and the dust luminosity of Suleiman et al. (2022) DOG sample, the SFR ranges of the sample according to different redshifts, and a comparison between Suleiman et al. (2022) sample and other samples of DOGs. [ABSTRACT FROM AUTHOR]

Over the last two decades, there has been a notable increase in the use of bistatic radar configurations for remote sensing, particularly employing Signals-of-Opportunity (SoOp), such as Global Navigation Satellite System - Reflectometry (GNSS-R). Unlike the more common monostatic backward radar configuration, GNSS-R forward scattering is dominated by different mechanisms. The forward scattering measurement provides valuable insights into regions where the backscatter is minimal or dominated by the double bounce effect caused by the vegetation. The Soil Moisture Active Passive (SMAP) mission carries an L-band radiometer and a radar. However, following a radar malfunction during its commissioning, the radar was repurposed to measure GPS L2C signals. This repurposing provides a unique opportunity to compare data from both the SMAP radar and GNSS-R (SMAP-R) collected by the same platform, using the same antenna, same incident angle, and similar frequencies. The study conducted offers a comprehensive analysis, both qualitative and quantitative, of the relationship between forward scattering at full polarization, and backward scattering at three polarizations (3-polarization: HH, VV and HV). Additionally, the study includes comparisons with ancillary geophysical measurements across three distinct areas with varying environmental characteristics, including dense forests and deserts. • There is a strong correlation between polarimetric GNSS-R and L-band radar. • Polarimetric GNSS-R provides complementary sensitivity over densely vegetated regions. • The relationship between forward and backward scattering is proportional but inverse. • Radar and reflectometry measurements complement each other over distinct areas. [ABSTRACT FROM AUTHOR]

• Electron-density diagnosis of the POINT system on the EAST was evaluated. • Experiment and simulation system VVUQ was applied to an entire plasma diagnostic system. • Uncertainties were identified, quantified, and minimized. • POINT system become a high-precision electron-density diagnostic system for the EAST. The verification, validation, and uncertainty quantification (VVUQ) analysis is a systematic method for identifying and quantifying uncertainties in complex engineering projects. This method has been used by the International Atomic Energy Agency as a critical assessment method in the field of high-precision plasma diagnostics in tokamaks. Starting from the basic theory to the final results, it assesses every process to obtain the uncertainties, system confidence level, and similarity between the model and experimental assessments. In this study, we evaluated the electron-density diagnosis of the polarimeter/interferometer system on an experimental advanced superconducting tokamak using a cylindrical simulation model. This study applied the VVUQ to an entire plasma diagnostic system for the first time, coupled with the statistical concepts of confidence and similarity. Through the VVUQ process, the uncertainty from the simulation code, diagnostic code, and engineering errors were identified, quantified, and minimized. [ABSTRACT FROM AUTHOR]