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Stanley Storgaard posted an update 3 months, 2 weeks ago
We found that among the MCP geometries, the increasing LD ratio corresponds to spectra that observe smaller FWHM and faster mean ToF, indicative of a significant drop in scattering. Additionally, the mass resolution is significantly better than when using the traditional carbon foil for masses above 4 amu. However, the geometry limits detection efficiencies due to the plasma’s reduced cross section of collision with the surface that generates the “Start” signal.A new dynamic foveated imager has been developed and commissioned on the wide-angle infra-red thermography system in the Experimental Advanced Superconducting Tokamak. This technique improves the local spatial resolution by a factor of 2 while maintaining the wide-angle view to ensure safety operation. Taking advantage of the new foveated imager, heat flux splitting under the application of resonant magnetic perturbation (RMP) coils has been clearly observed. The results indicate that the toroidal asymmetric power load pattern is closely related to the perturbation field induced by the RMP coils.We report the in-house fabrication of a high-resolution Fourier-transform spectrometer (FTS) for the spectroscopy of molecules in the gas phase at resolutions down to 0.002 cm-1 working in the spectral range from 5880 cm-1 (1.7 μm) to 15 380 cm-1 (650 nm). The FTS employs a supercontinuum as a broadband light source and a HeNe laser with a homemade frequency-stabilization scheme as the spatial reference for the sampling of the interferogram on a constant optical path difference (OPD) grid. The sampling of the two lasers is performed at constant time intervals, and the resampling process is performed at the software level. The resampling of the interferogram on a constant OPD grid relies on cubic approximations of the HeNe interference pattern to determine its zero-crossings. The use of an invariant in the sampling process allows us to perform on-the-fly data treatment. Both the hardware aspect and the data processing are described with, in each case, an original approach. We also report the successful coupling of the FTS with a high finesse optical cavity with effective mirror reflectivities of 99.76%, allowing us to reach sensitivities down to 6.5 × 10-8 cm-1 with a root-mean-square accuracy of 0.0017 cm-1 on the position of the Doppler-broadened transitions with a mean transition width of 0.046 cm-1 for spectra recorded at a spectral resolution of 0.015 cm-1. The sensitivity of the instrument per spectral element, once normalized, represents the best sensitivity reported in the literature for Fourier-transform incoherent broadband cavity-enhanced absorption spectroscopy with a supercontinuum light source.In this paper, a modular and open micro X-ray Computed Tomography (μXRCT) system is presented, which was set up during the last years at the Institute of Applied Mechanics (CE) of the University of Stuttgart and earlier at the Institute of Computational Engineering of Ruhr-University Bochum. The system is characterized by its intrinsic flexibility resulting from the modular and open design on each level and the opportunity to implement advanced experimental in situ setups. On the one hand, the presented work is intended to support researchers interested in setting up an experimental XRCT system for the microstructural characterization of materials. On the other hand, it aims to support scientists confronted with the decision to set up a system on their own or to buy a commercial scanner. In addition to the presentation of the various hardware components and the applied modular software concept, the technical opportunities of the open and modular hard- and software design are demonstrated by implementing a simple and reliable method for the compensation of bad detector pixels to enhance the raw data quality of the projections. A detailed investigation of the performance of the presented system with regard to the achievable spatial resolution is presented. XRCT datasets of three different applications are finally shown and discussed, demonstrating the wide scope of options of the presented system.A systematic and automated procedure to calculate the temperature of a surface with unknown emissivity from radiance measurements performed at a large number of wavelengths is presented, and statistical methods are applied to quantify its accuracy and precision. Unlike existing multi-wavelength pyrometric approaches, the proposed cross-validated procedure tests multiple emissivity candidates on multiple, randomly chosen subsets of the radiance measurements. The procedure uses solely an emissivity model to provide an accurate temperature value and retrieves the true emissivity from the ratio of the measured radiance to that of a blackbody calculated from the determined temperature. For a given emissivity model, the temperature is computed using the average of all possible combinations of two-wavelength ratios. The emissivity model that minimizes the coefficient of dispersion is selected. Accuracy and precision are quantified for the case of known emissivity. It is shown that, at least in the case where wavelengths are linearly distributed, the method is accurate, the precision increases with the total number of wavelengths, and it is maximized if the ratio of the minimum to maximum wavelength is equal to 2.46. The procedure is applied to both numerical and experimental data from the literature. Excellent agreement of the calculated temperature and emissivity is obtained for both datasets.This paper reports on the design and characteristics of a compact module integrating an optical displacement sensor and an electromagnetic actuator for use with vibration-isolation systems installed in KAGRA, the 3-km baseline gravitational-wave detector in Japan. In the technical concept, the module belongs to a family tree of similar modules used in other interferometric gravitational-wave detector projects. After the initial test run of KAGRA in 2016, the sensor part, which is a type of slot sensor, was modified by increasing the spacing of the slot from 5 mm to 15 mm to avoid the risk of mechanical interference with the sensor flag. We confirm that the sensor performance is comparable to that of the previous design despite the modification. click here We also confirm that the sensor noise is consistent with the theoretical noise budget. The noise level is 0.5 nm/Hz1/2 at 1 Hz and 0.1 nm/Hz1/2 at 10 Hz, and the linear range of the sensor is 0.7 mm or more. We measured the response of the actuator to be 1 N/A and also measured the resistances and inductances of coils of the actuators to confirm consistency with theory.