Experiences on production - usage reasoned malfunctions & development of  X-ray tubes used in science and their effects on sediment measurements

Author(s):  
Dursun Acar ◽  
Namık Çagatay ◽  
Ş. Can Genç ◽  
K. Kadir Eriş ◽  
Demet Biltekin ◽  
...  

<p>Surface fractures at the filament of X-ray tube increase more with metal fatique or wrong cooling  and heating processes. Fractured filament continue to work as repeating open circuit positions in random times with  turning fully conductive state in short time. We are explaining how open circuit flashes at the filament providing wrong measurement results. Their low voltage electric circuit conductive problems  repeat in milliseconds periods. At  the results, it gives the impression of healthy measurement values. Because that the measured sample absorbs photonic energy and direct it to neighbouring elements in continuous element  electron scattering  circulations , by the way that delayed secondary electron energy scatters hide all electron supply extinctions on the semi broken flament wire and indirect counts  continue by the detector from coming reflection energy. ( real counts are not from exact beam  target of sample surface during energy deprivations , and it is impossible to understand that the measurement is inaccurate because it causes similarity as discrete element counts in sedimentation layers ).  Filament voltage arcs do not warn machine with error reporting systems until to whole ruptured filament touch to anode walls or their far displaced edges of 2 broken filament positioning. Erroneous records take their place in the world of science if the lithology was not followed. We collected faulty measurement data from our experiences for indicate when and  how possible to facing such as events.</p><p>For eliminate  explained reasons at above , the tubes must be gently heated and  cooled. Excessive cooling or heating of the tubes or oxid placement and leakeage  at gasget contacts reduces the surface contact areas of the insilators with the corrosion by  condensing water around the rubber insulation gasgets , it causes cooling liquid leakage or increasing humidity at the tube housing block via following serial failures of HV unit such as increasing amounts of the broken tube events. During the replacement of insulating gasgets, enough care should be taken for gasket contact points as oiling  them with  silicone grease as a form of the thin film. High responsibility must be with continuous  result control  and reference correlations on the scientific sample. With this way we can eliminate possible  negative results by malfunctions on measurements.</p>

2019 ◽  
Vol 87 (2) ◽  
pp. 67-73 ◽  
Author(s):  
Michele Boracchi ◽  
Graziano Domenico Luigi Crudele ◽  
Guendalina Gentile ◽  
Francesca Maciocco ◽  
Francesca Maghin ◽  
...  

Literature on electrocution in Italy is limited. The authors have focused their attention on the use of scanning electron microscope/energy-dispersive X-ray analysis in order to evaluate the current mark even on paraffin-embedded samples. A total of 24,104 autopsies were performed at the Section of Legal Medicine of Milan (1993–2017); all cases of death caused by electrocution (low and high voltage) were selected. We assessed a regular histological examination, a toxicological examination and detected metallisation with energy-dispersive X-ray spectroscopy analysis on paraffin-embedded tissues of typical current marks. We collected 27 high-voltage fatalities and five cases of low-voltage suicide electrocution; the technique revealed itself as sensitive. In all cases, microscopic examination highlighted the typical signs of electric current and thermal damage but the histochemical specific stainings for copper and iron gave negative results. Scanning electron microscope/energy-dispersive X-ray analysis, assessed on these same samples, even when paraffin-embedded, however, enabled us to detect these elements and differentiate between the various metal residues involved in the electrocution process. Based on their experience, authors advise the use of scanning electron microscope/energy-dispersive X-ray analysis on electrocution deaths to provide information for forensic diagnosis.


Author(s):  
A.J. Tousimis

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.


Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265 ◽  
Author(s):  
Johanna Geis-Schroer ◽  
Sebastian Hubschneider ◽  
Lukas Held ◽  
Frederik Gielnik ◽  
Michael Armbruster ◽  
...  

In this contribution, measurement data of phase, neutral, and ground currents from real low voltage (LV) feeders in Germany is presented and analyzed. The data obtained is used to review and evaluate common modeling approaches for LV systems. An alternative modeling approach for detailed cable and ground modeling, which allows for the consideration of typical German LV earthing conditions and asymmetrical cable design, is proposed. Further, analytical calculation methods for model parameters are described and compared to laboratory measurement results of real LV cables. The models are then evaluated in terms of parameter sensitivity and parameter relevance, focusing on the influence of conventionally performed simplifications, such as neglecting house junction cables, shunt admittances, or temperature dependencies. By comparing measurement data from a real LV feeder to simulation results, the proposed modeling approach is validated.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rui Su ◽  
Zhaojian Xu ◽  
Jiang Wu ◽  
Deying Luo ◽  
Qin Hu ◽  
...  

AbstractThe performance of perovskite photovoltaics is fundamentally impeded by the presence of undesirable defects that contribute to non-radiative losses within the devices. Although mitigating these losses has been extensively reported by numerous passivation strategies, a detailed understanding of loss origins within the devices remains elusive. Here, we demonstrate that the defect capturing probability estimated by the capture cross-section is decreased by varying the dielectric response, producing the dielectric screening effect in the perovskite. The resulting perovskites also show reduced surface recombination and a weaker electron-phonon coupling. All of these boost the power conversion efficiency to 22.3% for an inverted perovskite photovoltaic device with a high open-circuit voltage of 1.25 V and a low voltage deficit of 0.37 V (a bandgap ~1.62 eV). Our results provide not only an in-depth understanding of the carrier capture processes in perovskites, but also a promising pathway for realizing highly efficient devices via dielectric regulation.


Author(s):  
Mingqiang Zhong ◽  
Qin Feng ◽  
Changlai Yuan ◽  
Xiao Liu ◽  
Baohua Zhu ◽  
...  

AbstractIn this work, the (1−x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-BNN; 0.00 ⩽ x ⩽ 0.20) ceramics were prepared via a high-temperature solid-state method. The crystalline structures, photovoltaic effect, and electrical properties of the ceramics were investigated. According to X-ray diffraction, the system shows a single perovskite structure. The samples show the normal ferroelectric loops. With the increase of BNN content, the remnant polarization (Pr) and coercive field (Ec) decrease gradually. The optical band gap of the samples narrows from 3.10 to 2.27 eV. The conductive species of grains and grain boundaries in the ceramics are ascribed to the double ionized oxygen vacancies. The open-circuit voltage (Voc) of ∼15.7 V and short-circuit current (Jsc) of ∼1450 nA/cm2 are obtained in the 0.95BNT-0.05BNN ceramic under 1 sun illumination (AM1.5G, 100 mW/cm2). A larger Voc of 23 V and a higher Jsc of 5500 nA/cm2 are achieved at the poling field of 60 kV/cm under the same light conditions. The study shows this system has great application prospects in the photovoltaic field.


Author(s):  
Asahina Shunsuke ◽  
Takahashi Hideyuki ◽  
Takakura Masaru ◽  
Ferdi Schüth ◽  
Terasaki Osamu

2002 ◽  
Vol 10 (2) ◽  
pp. 22-23 ◽  
Author(s):  
David C Joy ◽  
Dale E Newbury

Low Voltage Scanning Electron Microscopy (LVSEM), defined as operation in the energy range below 5 keV, has become perhaps the most important single operational mode of the SEM. This is because the LVSEM offers advantages in the imaging of surfaces, in the observation of poorly conducting and insulating materials, and for high spatial resolution X-ray microanalysis. These benefits all occur because a reduction in the energy Eo of the incident beam leads to a rapid fall in the range R of the electrons since R ∼k.E01.66. The reduction in the penetration of the beam has important consequences.


1993 ◽  
Vol 34 (4) ◽  
pp. 346-350 ◽  
Author(s):  
S. Sone ◽  
T. Kasuga ◽  
F. Sakai ◽  
H. Hirano ◽  
K. Kubo ◽  
...  

Dual-energy subtraction digital tomosynthesis with pulsed X-ray and rapid kV switching was used to examine calcifications in pulmonary lesions. The digital tomosynthesis system used included a conventional fluororadiographic TV unit with linear tomographic capabilities, a high resolution videocamera, and an image processing unit. Low-voltage, high-voltage, and soft tissue subtracted or bone subtracted tomograms of any desired layer height were reconstructed from the image data acquired during a single tomographic swing. Calcifications, as well as their characteristics and distribution in pulmonary lesions, were clearly shown. The images also permitted discrimination of calcifications from dense fibrotic lesions. This technique was effective in demonstrating calcifications together with a solitary mass or disseminated nodules.


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