Numerical simulations in support of the design of an ultrasonic device for sub-assembly identification

In this paper, it is shown how numerical simulations can help designing an ultrasonic instrument operating in harsh conditions. To prevent fuel handling errors in sodium cooled fast reactors, the identification of fuel sub-assemblies using ultrasound is being investigated. It is based on the interpretation of a code (aligned notches) engraved on the sub-assembly head using an emitting/receiving ultrasonic sensor. This reading is performed in liquid sodium with high temperature (up to 600°C) transducers. A first experiment in liquid sodium demonstrated the feasibility of this method. The reading quality and robustness depend on various parameters related to the ultrasonic beam (spectral response, focal distance, focal spot size), the code geometry (especially the notches’ dimensions) and geometrical alignments. In order to avoid numerous experiments, two numerical models are developed. The first one is a finite element simulation of the sensor providing its radiated field. This model is validated with the well-known analytic solution of the Rayleigh integral; then it is applied to the sensor used in the sodium experiment. The focal distance and focal spot diameter are close to the expected values. The second simulation, using CIVA software, provides the ultrasonic scan of the code. The result is in good agreement with the sodium experiment and a first comparison with a water experiment shows that this numerical tool is relevant for easily taking into account misalignment and misorientation of the scan.

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XRMF applications of a monolithic, polycapillary, focusing x-ray optic

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163666 ◽

1996 ◽

Vol 54 ◽

pp. 240-241

Author(s):

D. A. Carpenter ◽

Ning Gao ◽

G. J. Havrilla

Keyword(s):

Trace Elements ◽

Point Source ◽

Focal Spot ◽

Fluorescence Analysis ◽

X Rays ◽

Focal Distance ◽

Spot Diameter ◽

X Ray ◽

Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

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Numerical Simulations of Laser-Driven Cratering Experiments into Porous Graphite

EPJ Web of Conferences ◽

10.1051/epjconf/201818301060 ◽

2018 ◽

Vol 183 ◽

pp. 01060

Author(s):

Bertrand Aubert ◽

David Hebert ◽

Jean-Luc Rullier ◽

Jean-Marc Chevalier ◽

Laurent Berthe ◽

...

Keyword(s):

Numerical Simulations ◽

Focal Spot ◽

Surface Velocity ◽

Power Laser ◽

Graphite Target ◽

Experimental Campaign ◽

Porous Graphite ◽

Thin Aluminum ◽

Laser Facility ◽

Focal Spot Diameter

We present the results of an experimental campaign conducted on the LULI2000 laser facility. Semi-infinite targets of a commercial grade of porous graphite were submitted to high-power laser irradiation inorder to generate craters. A 15 ns pulse duration was used along with a focal spot diameter of 900 µm to deliver energies up to 750 J. Numerical simulations of these shots have been performed following a specificmethodology which can be divided in three steps. Firstly, the mechanical loading induced by the laser iscalibrated by simulating the same shot on a thin aluminum target of which free surface velocity is measured byPDV and line-VISAR. Secondly, the same shot is performed on a thin graphite target to validate the materialmodel of graphite. Thirdly, the craterization shot on semi-infinite target is simulated. Numerical results arecompared to experimental measurements of craters obtained using an interferometric profilometer.

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Computational Technique for the Qualification of Focal Spot Size and Shape of Industrial Radioscopy Equipment Using Star Patterns

Materials Evaluation ◽

10.32548/2020.me-04044 ◽

2020 ◽

Vol 78 (4) ◽

pp. 479-486

Author(s):

Marcela Tatiana Fernandes Beserra ◽

◽

Ricardo Tadeu Lopes ◽

Davi Ferreira de Oliveira ◽

Claudio Carvalho Conti ◽

...

Keyword(s):

Focal Spot ◽

Spot Size ◽

Computational Technique ◽

Focal Spot Size ◽

Size And Shape

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Dependence of laser accelerated protons on laser energy following the interaction of defocused, intense laser pulses with ultra-thin targets

Laser and Particle Beams ◽

10.1017/s0263034611000395 ◽

2011 ◽

Vol 29 (3) ◽

pp. 345-351 ◽

Cited By ~ 22

Author(s):

C.M. Brenner ◽

J.S. Green ◽

A.P.L. Robinson ◽

D.C. Carroll ◽

B. Dromey ◽

...

Keyword(s):

Laser Pulse ◽

Focal Spot ◽

Laser Pulse Energy ◽

Laser Energy ◽

Spot Size ◽

Proton Flux ◽

Focal Spot Size ◽

Order Of Magnitude ◽

Laser Focal Spot ◽

Accelerated Protons

AbstractThe scaling of the flux and maximum energy of laser-driven sheath-accelerated protons has been investigated as a function of laser pulse energy in the range of 15–380 mJ at intensities of 1016–1018 W/cm2. The pulse duration and target thickness were fixed at 40 fs and 25 nm, respectively, while the laser focal spot size and drive energy were varied. Our results indicate that while the maximum proton energy is dependent on the laser energy and laser spot diameter, the proton flux is primarily related to the laser pulse energy under the conditions studied here. Our measurements show that increasing the laser energy by an order of magnitude results in a more than 500-fold increase in the observed proton flux. Whereas, an order of magnitude increase in the laser intensity generated by decreasing the laser focal spot size, at constant laser energy, gives rise to less than a tenfold increase in observed proton flux.

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The determination of the focal spot size of an X-ray tube from the radiation beam profile

Radiation Measurements ◽

10.1016/j.radmeas.2015.09.010 ◽

2015 ◽

Vol 82 ◽

pp. 138-145 ◽

Cited By ~ 3

Author(s):

A.D. Oliveira ◽

M.J. Fartaria ◽

J. Cardoso ◽

L.M. Santos ◽

C. Oliveira ◽

...

Keyword(s):

Focal Spot ◽

Spot Size ◽

Beam Profile ◽

Focal Spot Size ◽

Radiation Beam ◽

X Ray

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Bremsstrahlung emission profile from intense laser-solid interactions as a function of laser focal spot size

Plasma Physics and Controlled Fusion ◽

10.1088/1361-6587/aaf596 ◽

2019 ◽

Vol 61 (3) ◽

pp. 034001 ◽

Cited By ~ 4

Author(s):

C D Armstrong ◽

C M Brenner ◽

E Zemaityte ◽

G G Scott ◽

D R Rusby ◽

...

Keyword(s):

Focal Spot ◽

Spot Size ◽

Intense Laser ◽

Focal Spot Size ◽

Emission Profile ◽

Bremsstrahlung Emission ◽

Laser Focal Spot ◽

Laser Solid Interactions

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Self-Focusing of Hermite-Cosh-Gaussian Laser Beams in Plasma under Density Transition

Advances in Optics ◽

10.1155/2014/942750 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Manzoor Ahmad Wani ◽

Niti Kant

Keyword(s):

Laser Beam ◽

Plasma Density ◽

Focal Spot ◽

Beam Width ◽

Spot Size ◽

Laser Beams ◽

Equation Approach ◽

Focal Spot Size ◽

Self Focusing ◽

Small Spot

Self-focusing of Hermite-Cosh-Gaussian (HChG) laser beam in plasma under density transition has been discussed here. The field distribution in the medium is expressed in terms of beam-width parameters and decentered parameter. The differential equations for the beam-width parameters are established by a parabolic wave equation approach under paraxial approximation. To overcome the defocusing, localized upward plasma density ramp is considered, so that the laser beam is focused on a small spot size. Plasma density ramp plays an important role in reducing the defocusing effect and maintaining the focal spot size up to several Rayleigh lengths. To discuss the nature of self-focusing, the behaviour of beam-width parameters with dimensionless distance of propagation for various values of decentered parameters is examined by numerical estimates. The results are presented graphically and the effect of plasma density ramp and decentered parameter on self-focusing of the beams has been discussed.

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rpe v5: An emulator for reduced floating-point precision in large numerical simulations

10.5194/gmd-2016-247 ◽

2016 ◽

Cited By ~ 2

Author(s):

Andrew Dawson ◽

Peter Düben

Keyword(s):

Numerical Simulations ◽

Climate Models ◽

Numerical Models ◽

Computational Cost ◽

Floating Point ◽

Climate Modelling ◽

Acceptable Quality ◽

Weather And Climate ◽

Code Changes ◽

Numerical Precision

Abstract. This paper describes the rpe library which has the capability to emulate the use of arbitrary reduced floating-point precision within large numerical models written in Fortran. The rpe software allows model developers to test how reduced floating-point precision affects the result of their simulations without having to make extensive code changes or port the model onto specialised hardware. The software can be used to identify parts of a program that are problematic for numerical precision and to guide changes to the program to allow a stronger reduction in precision. The development of rpe was motivated by the strong demand for more computing power. If numerical precision can be reduced for an application under consideration while still achieving results of acceptable quality, computational cost can be reduced, since a reduction in numerical precision may allow an increase in performance or a reduction in power consumption. For simulations with weather and climate models, savings due to a reduction in precision could be reinvested to allow model simulations at higher spatial resolution or complexity, or to increase the number of ensemble members to improve predictions. rpe was developed with particular focus on the community of weather and climate modelling, but the software could be used with numerical simulations from other domains.

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The investigation of the features optical vortices focusing by ring gratings with the variable height using high-performance computer systems

Journal of Physics Conference Series ◽

10.1088/1742-6596/2086/1/012166 ◽

2021 ◽

Vol 2086 (1) ◽

pp. 012166

Author(s):

D A Savelyev

Keyword(s):

High Performance ◽

Focal Spot ◽

Fdtd Method ◽

Spot Size ◽

Laser Beams ◽

Optical Vortices ◽

Focal Spot Size ◽

Near Zone ◽

High Performance Computer ◽

Difference Time

Abstract The diffraction of vortex laser beams with circular polarization by ring gratings with the variable height was investigated in this paper. Modelling of near zone diffraction is numerically investigated by the finite difference time domain (FDTD) method. The changes in the length size of the light needle and focal spot size are shown depending on the type of the ring grating.

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