Sub-electron noise measurements on repetitive non-destructive readout devices

2006 ◽  
Vol 566 (2) ◽  
pp. 536-539 ◽  
Author(s):  
Stefan Wölfel ◽  
Sven Herrmann ◽  
Peter Lechner ◽  
Gerhard Lutz ◽  
Matteo Porro ◽  
...  
Keyword(s):  
Noise Measurements ◽  
Non Destructive

scholarly journals Case Depth Prediction of Nitrided Samples with Barkhausen Noise Measurement

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 325 ◽  
Author(s):  
Aki Sorsa ◽  
Suvi Santa-aho ◽  
Christopher Aylott ◽  
Brian Shaw ◽  
Minnamari Vippola ◽  
...  
Keyword(s):  
Quality Control ◽  
Diffusion Layer ◽  
Measurement Data ◽  
Case Depth ◽  
Barkhausen Noise ◽  
Efficient Production ◽  
Depth Prediction ◽  
Noise Measurements ◽  
Non Destructive ◽  
And Diffusion

Nitriding is a heat treatment process that is commonly used to enhance the surface properties of ferrous components. Traditional quality control uses sacrificial pieces that are destructively evaluated. However, efficient production requires quality control where the case depths produced are non-destructively evaluated. In this study, four different low alloy steel materials were studied. Nitriding times for the samples were varied to produce varying case depths. Traditional Barkhausen noise and Barkhausen noise sweep measurements were carried out for non-destructive case depth evaluation. A prediction model between traditional Barkhausen noise measurements and diffusion layer hardness was identified. The diffusion layer hardness was predicted and sweep measurement data was used to predict case depths. Modelling was carried out for non-ground and ground samples with good results.

scholarly journals Low–Frequency Noise Measurements Used For Quality Assessment Of GaSb Based Laser Diodes Prepared By Molecular Beam Epitaxy

2015 ◽  
Vol 66 (4) ◽  
pp. 226-230
Author(s):  
Zdeněk Chobola ◽  
Miroslav Luňák ◽  
Jiří Vaněk ◽  
Eduard Hulicius ◽  
Ivo Kusák
Keyword(s):  
Molecular Beam Epitaxy ◽  
Semiconductor Lasers ◽  
Molecular Beam ◽  
Low Frequency ◽  
Cavity Surface ◽  
Frequency Noise ◽  
Vertical Cavity Surface ◽  
Noise Measurements ◽  
Vertical Cavity ◽  
Non Destructive

Abstract The paper reports on a non-destructive method of reliability prediction for semiconductor lasers diodes GaSb based VCSE (vertical cavity surface emitting). Transport and noise characteristic of forward biased were measured in order to evaluate the new MBE (molecular beam epitaxy) technology. The results demonstrate that the lasers prepared by new MBE technology have higher quality than the samples prepared by using the classic MBE technology.

Reduced False Calls in Eddy Current Images Using Signal Processing

2021 ◽  
Author(s):  
S. B. Mahalakshmi ◽  
Ganesh Seshadri ◽  
Aparna Sheila-Vadde ◽  
Manoj Kumar KM
Keyword(s):  
Eddy Current ◽  
Flaw Detection ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Noise Measurements ◽  
Component Manufacturing ◽  
Lift Off ◽  
The Time Domain ◽  
Non Destructive

Abstract Non-destructive testing methods are used largely in component manufacturing industries like Aerospace, Renewables and Power to evaluate the properties of a material or the quality of a component by inspecting for cracks and discontinuities without causing damage to the part. Among the many non-destructive testing methods, Eddy current imaging enables efficient flaw detection for surface and sub-surface cracks. However, in typical eddy current inspection, there can be significant number of false calls arising from variation in lift-off and surface anomalies. Discriminating defect signals from false calls can be very challenging. This paper describes a method to reduce false calls by using a wavelet based denoising algorithm and combining it with statistical-based features extracted inside a sliding window in the time domain to efficiently identify the cracks. The results are verified on specimens with cracks of different sizes that are oriented randomly along with locations available for baseline noise measurements.

Physics and Modeling of Magnetic Non Destructive Testing Techniques

2011 ◽  
Vol 495 ◽  
pp. 265-268
Author(s):  
Aphrodite Ktena
Keyword(s):  
Domain Wall ◽  
Magnetic Domain ◽  
Wall Structure ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Surface Stresses ◽  
Yield Information ◽  
Noise Measurements ◽  
Domain Wall Propagation ◽  
Non Destructive

Magnetic Non Destructive Testing (MNDT) methods are a tool not limited in the detection of cracks and defects, like traditional NDT methods for ferrous structures, but they have shown a potential for the monitoring of the structure and crack prevention. MNDT techniques include surface Magnetic Barkhausen Noise measurements (MBN) yielding localized information about the surface stresses and magnetization processes in the vicinity of the measurement; the use of Magnetostrictive Delay Lines (MDL) for the measurement of surface stresses; the Magneto Acoustic Emission (MAE), revealing information about the magnetic domain wall propagation and indirectly about the underlying structure’s role in the magnetization process of the material; magnetic major and minor loop (B-H) bulk measurements which yield information on the macroscopic magnetic properties of the material such as, the coercivity, Hc, the remanence, Br, or the permeability, µ. Results show that changes in these properties are definite signs of non-uniformly distributed stresses along the material and reveal a definitive dependence of the various magnetization reversal mechanisms such as domain wall propagation and domain rotation on the microstructure of the material,eg, the domain wall structure, the effect of dislocations, the grain size, built-in stresses. However, the quantitative mapping of the MNDT results to the microstructure and from there to the possibility of crack generation and propagation is still a very attractive but open question. Modeling at the atomic level involving Ising Models, at the microscopic level using micromagnetic calculations and at the macroscopic level employing the Preisach formalism, has so far provided useful insight. The use of modeling in order to not only explain experimental results but in forecasting is expected to greatly enhance the position of the MNDT techniques in industrial NDT.

scholarly journals Non-Destructive Characterization of Micro-Sized Defects in the Solar Cell Structure

2011 ◽  
Vol 465 ◽  
pp. 314-317
Author(s):  
Robert Macku ◽  
Pavel Koktavý ◽  
Pavel Škarvada
Keyword(s):  
Solar Cells ◽  
Cell Structure ◽  
Direct Consequence ◽  
Solar Cell Structure ◽  
Noise Measurements ◽  
Measurement Methodology ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Non Destructive Characterization

This article discusses the issue of noise measurements application for the quality assessment of the solar cells themselves and production technology alike. The main focus of our research is the random n-level (in most case just two-level) impulse noise, usually referred to as microplasma noise. This noise was found to be in a direct consequence of local breakdowns in micro-sized regions and brings about a reduction of lifetime or a destruction of the pn junction. Non-destructive measurement methodology as presented here is suitable for testing of a large number of various semiconductor devices not only for solar cells. In this paper experimental measurement of noise signals in the frequency and time domain is presented. Furthermore the microplasma noise behaviour and defect geometry is discussed.

Luminescence from individual dislocations in II-VI and III-V semiconductors

1991 ◽  
Vol 49 ◽  
pp. 834-835
Author(s):  
J W Steeds
Keyword(s):  
Group Iv ◽  
Luminescence Properties ◽  
Carrier Recombination ◽  
Transmission Electron ◽  
Wide Range ◽  
Basic Physics ◽  
Semiconducting Compounds ◽  
Diamond Group ◽  
Non Destructive ◽  
Technological Significance

There is a wide range of experimental results related to dislocations in diamond, group IV, II-VI, III-V semiconducting compounds, but few of these come from isolated, well-characterized individual dislocations. We are here concerned with only those results obtained in a transmission electron microscope so that the dislocations responsible were individually imaged. The luminescence properties of the dislocations were studied by cathodoluminescence performed at low temperatures (~30K) achieved by liquid helium cooling. Both spectra and monochromatic cathodoluminescence images have been obtained, in some cases as a function of temperature.There are two aspects of this work. One is mainly of technological significance. By understanding the luminescence properties of dislocations in epitaxial structures, future non-destructive evaluation will be enhanced. The second aim is to arrive at a good detailed understanding of the basic physics associated with carrier recombination near dislocations as revealed by local luminescence properties.

Forensic Identifications Aided by Scanning Electron Microscopy of Silicone-Epoxy Microreplicas of Calcified and Cornified Structures

1975 ◽  
Vol 33 ◽  
pp. 678-679 ◽  
Author(s):  
R.F. Sognnaes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Forensic Science ◽  
George Washington ◽  
Epithelial Surface ◽  
Extended Application ◽  
Tissue Surfaces ◽  
Non Destructive ◽  
Scanning Electron ◽  
Surface Changes

Sufficient experience has been gained during the past five years to suggest an extended application of microreplication and scanning electron microscopy to problems of forensic science. The author's research was originally initiated with a view to develop a non-destructive method for identification of materials that went into objects of art, notably ivory and ivories. This was followed by a very specific application to the identification and duplication of the kinds of materials from animal teeth and tusks which two centuries ago went into the fabrication of the ivory dentures of George Washington. Subsequently it became apparent that a similar method of microreplication and SEM examination offered promise for a whole series of problems pertinent to art, technology and science. Furthermore, what began primarily as an application to solid substances has turned out to be similarly applicable to soft tissue surfaces such as mucous membranes and skin, even in cases of acute, chronic and precancerous epithelial surface changes, and to post-mortem identification of specific structures pertinent to forensic science.

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