Polarization ray tracing in anisotropic optically active media. II. Theory and physics

International Nuclear Information System (INIS)

McClain, S.C.; Hillman, L.W.; Chipman, R.A.

1993-01-01

Refraction, reflection, and amplitude relations are derived that apply to polarization ray tracing in anisotropic, optically active media such as quartz. The constitutive relations for quartz are discussed. The refractive indices and polarization states associated with the two modes of propagation are derived as a function of wave direction. A procedure for refracting at any uniaxial or optically active interface is derived that computes both the ray direction and the wave direction. A method for computing the optical path length is given, and Fresnel transmission and ref lection equations are derived from boundary conditions on the electromagnetic fields. These ray-tracing formulas apply to uniaxial, optically active media and therefore encompass uniaxial, non-optically active materials and isotropic, optically active materials

The Alba ray tracing code: ART

Science.gov (United States)

Nicolas, Josep; Barla, Alessandro; Juanhuix, Jordi

2013-09-01

The Alba ray tracing code (ART) is a suite of Matlab functions and tools for the ray tracing simulation of x-ray beamlines. The code is structured in different layers, which allow its usage as part of optimization routines as well as an easy control from a graphical user interface. Additional tools for slope error handling and for grating efficiency calculations are also included. Generic characteristics of ART include the accumulation of rays to improve statistics without memory limitations, and still providing normalized values of flux and resolution in physically meaningful units.

Real time ray tracing based on shader

Science.gov (United States)

Gui, JiangHeng; Li, Min

2017-07-01

Ray tracing is a rendering algorithm for generating an image through tracing lights into an image plane, it can simulate complicate optical phenomenon like refraction, depth of field and motion blur. Compared with rasterization, ray tracing can achieve more realistic rendering result, however with greater computational cost, simple scene rendering can consume tons of time. With the GPU's performance improvement and the advent of programmable rendering pipeline, complicated algorithm can also be implemented directly on shader. So, this paper proposes a new method that implement ray tracing directly on fragment shader, mainly include: surface intersection, importance sampling and progressive rendering. With the help of GPU's powerful throughput capability, it can implement real time rendering of simple scene.

Application of ray tracing towards a correction for refracting effects in computed tomography with diffracting sources

International Nuclear Information System (INIS)

Andersen, A.H.

1983-01-01

Ray tracing methods are investigated in forward and inverse processes and applied for image restoration and resolution enhancement in computed tomography with diffracting sources. Within the geometrical optics approximation for a given refractive field, a mathematical model for the forward propagation and inverse reconstruction process is presented. For a finite set of rays in a discrete image representation, an algebraic reconstruction technique is derived which is analogous to the inverse process for a continuum of rays. The geometrical theory of diffraction is invoked to describe ray patterns arising from the introduction of object discontinuity surfaces. We have compared the performance of existing recursive ray tracing techniques for the reconstruction of objects exhibiting discontinuity boundaries. A novel ray tracing and reconstruction technique is presented which enjoys significant computational savings over traditional implementations incorporating tedious ray linking procedures. Simulation studies illustrate the macro-structural distortion and loss of fine resolution when ray refraction is unaccounted for. Restoration and resolution enhancement is achieved with a recursive ray tracing approach. Successful experimental studies with tissue equivalent phantoms are presented. The comparison of simulation and experimental results demonstrated the reasonable assumption of the geometrical optics approximation. Simulation results for larger refractive deviations are encouraging

Computer program for optical systems ray tracing

Science.gov (United States)

Ferguson, T. J.; Konn, H.

1967-01-01

Program traces rays of light through optical systems consisting of up to 65 different optical surfaces and computes the aberrations. For design purposes, paraxial tracings with astigmation and third order tracings are provided.

Development of ray tracing visualization program by Monte Carlo method

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Kenji; Otani, Takayuki [Japan Atomic Energy Research Inst., Tokyo (Japan); Hasegawa, Yukihiro

1997-09-01

Ray tracing algorithm is a powerful method to synthesize three dimensional computer graphics. In conventional ray tracing algorithms, a view point is used as a starting point of ray tracing, from which the rays are tracked up to the light sources through center points of pixels on the view screen to calculate the intensities of the pixels. This manner, however, makes it difficult to define the configuration of light source as well as to strictly simulate the reflections of the rays. To resolve these problems, we have developed a new ray tracing means which traces rays from a light source, not from a view point, with use of Monte Carlo method which is widely applied in nuclear fields. Moreover, we adopt the variance reduction techniques to the program with use of the specialized machine (Monte-4) for particle transport Monte Carlo so that the computational time could be successfully reduced. (author)

RayTrace: A Simplified Ray Tracing Software for use in AutoCad

DEFF Research Database (Denmark)

Reimann, Gregers Peter; Tang, C.K.

2005-01-01

A design aid tool for testing and development of daylighting systems was developed. A simplified ray tracing software was programmed in Lisp for AutoCad. Only fully specularly reflective, fully transparent and fully absorbant surfaces can be defined in the software. The software is therefore best...

AXAF FITS standard for ray trace interchange

Science.gov (United States)

Hsieh, Paul F.

1993-07-01

A standard data format for the archival and transport of x-ray events generated by ray trace models is described. Upon review and acceptance by the Advanced X-ray Astrophysics Facility (AXAF) Software Systems Working Group (SSWG), this standard shall become the official AXAF data format for ray trace events. The Flexible Image Transport System (FITS) is well suited for the purposes of the standard and was selected to be the basis of the standard. FITS is both flexible and efficient and is also widely used within the astronomical community for storage and transfer of data. In addition, software to read and write FITS format files are widely available. In selecting quantities to be included within the ray trace standard, the AXAF Mission Support team, Science Instruments team, and the other contractor teams were surveyed. From the results of this survey, the following requirements were established: (1) for the scientific needs, each photon should have associated with it: position, direction, energy, and statistical weight; the standard must also accommodate path length (relative phase), and polarization. (2) a unique photon identifier is necessary for bookkeeping purposes; (3) a log of individuals, organizations, and software packages that have modified the data must be maintained in order to create an audit trail; (4) a mechanism for extensions to the basic kernel should be provided; and (5) the ray trace standard should integrate with future AXAF data product standards.

X-ray fluorescence method for trace analysis and imaging

International Nuclear Information System (INIS)

Hayakawa, Shinjiro

2000-01-01

X-ray fluorescence analysis has a long history as conventional bulk elemental analysis with medium sensitivity. However, with the use of synchrotron radiation x-ray fluorescence method has become a unique analytical technique which can provide tace elemental information with the spatial resolution. To obtain quantitative information of trace elemental distribution by using the x-ray fluorescence method, theoretical description of x-ray fluorescence yield is described. Moreover, methods and instruments for trace characterization with a scanning x-ray microprobe are described. (author)

The vectorization of a ray tracing program for image generation

Science.gov (United States)

Plunkett, D. J.; Cychosz, J. M.; Bailey, M. J.

1984-01-01

Ray tracing is a widely used method for producing realistic computer generated images. Ray tracing involves firing an imaginary ray from a view point, through a point on an image plane, into a three dimensional scene. The intersections of the ray with the objects in the scene determines what is visible at the point on the image plane. This process must be repeated many times, once for each point (commonly called a pixel) in the image plane. A typical image contains more than a million pixels making this process computationally expensive. A traditional ray tracing program processes one ray at a time. In such a serial approach, as much as ninety percent of the execution time is spent computing the intersection of a ray with the surface in the scene. With the CYBER 205, many rays can be intersected with all the bodies im the scene with a single series of vector operations. Vectorization of this intersection process results in large decreases in computation time. The CADLAB's interest in ray tracing stems from the need to produce realistic images of mechanical parts. A high quality image of a part during the design process can increase the productivity of the designer by helping him visualize the results of his work. To be useful in the design process, these images must be produced in a reasonable amount of time. This discussion will explain how the ray tracing process was vectorized and gives examples of the images obtained.

Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

Science.gov (United States)

Hofmeister, Armin; Böhm, Johannes

2017-08-01

The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the

Ray tracing reconstruction investigation for C-arm tomosynthesis

Science.gov (United States)

Malalla, Nuhad A. Y.; Chen, Ying

2016-04-01

C-arm tomosynthesis is a three dimensional imaging technique. Both x-ray source and the detector are mounted on a C-arm wheeled structure to provide wide variety of movement around the object. In this paper, C-arm tomosynthesis was introduced to provide three dimensional information over a limited view angle (less than 180o) to reduce radiation exposure and examination time. Reconstruction algorithms based on ray tracing method such as ray tracing back projection (BP), simultaneous algebraic reconstruction technique (SART) and maximum likelihood expectation maximization (MLEM) were developed for C-arm tomosynthesis. C-arm tomosynthesis projection images of simulated spherical object were simulated with a virtual geometric configuration with a total view angle of 40 degrees. This study demonstrated the sharpness of in-plane reconstructed structure and effectiveness of removing out-of-plane blur for each reconstruction algorithms. Results showed the ability of ray tracing based reconstruction algorithms to provide three dimensional information with limited angle C-arm tomosynthesis.

Simplifying numerical ray tracing for two-dimensional non circularly symmetric models of the human eye.

Science.gov (United States)

Jesus, Danilo A; Iskander, D Robert

2015-12-01

Ray tracing is a powerful technique to understand the light behavior through an intricate optical system such as that of a human eye. The prediction of visual acuity can be achieved through characteristics of an optical system such as the geometrical point spread function. In general, its precision depends on the number of discrete rays and the accurate surface representation of each eye's components. Recently, a method that simplifies calculation of the geometrical point spread function has been proposed for circularly symmetric systems [Appl. Opt.53, 4784 (2014)]. An extension of this method to 2D noncircularly symmetric systems is proposed. In this method, a two-dimensional ray tracing procedure for an arbitrary number of surfaces and arbitrary surface shapes has been developed where surfaces, rays, and refractive indices are all represented in functional forms being approximated by Chebyshev polynomials. The Liou and Brennan anatomically accurate eye model has been adapted and used for evaluating the method. Further, real measurements of the anterior corneal surface of normal, astigmatic, and keratoconic eyes were substituted for the first surface in the model. The results have shown that performing ray tracing, utilizing the two-dimensional Chebyshev function approximation, is possible for noncircularly symmetric models, and that such calculation can be performed with a newly created Chebfun toolbox.

Use of X-Ray Fluorescence Spectrometry to Determine Trace ...

African Journals Online (AJOL)

This paper deals with application of X-ray fluorescence spectrometry for the detection of trace elements in graphic. An X-ray spectrometer was constructed and used to carry out measurements on graphite spheres impregnated with different chemical elements. The intensities of the lines of these trace elements, as function of ...

GPU-accelerated ray-tracing for real-time treatment planning

International Nuclear Information System (INIS)

Heinrich, H; Ziegenhein, P; Kamerling, C P; Oelfke, U; Froening, H

2014-01-01

Dose calculation methods in radiotherapy treatment planning require the radiological depth information of the voxels that represent the patient volume to correct for tissue inhomogeneities. This information is acquired by time consuming ray-tracing-based calculations. For treatment planning scenarios with changing geometries and real-time constraints this is a severe bottleneck. We implemented an algorithm for the graphics processing unit (GPU) which implements a ray-matrix approach to reduce the number of rays to trace. Furthermore, we investigated the impact of different strategies of accessing memory in kernel implementations as well as strategies for rapid data transfers between main memory and memory of the graphics device. Our study included the overlapping of computations and memory transfers to reduce the overall runtime using Hyper-Q. We tested our approach on a prostate case (9 beams, coplanar). The measured execution times for a complete ray-tracing range from 28 msec for the computations on the GPU to 99 msec when considering data transfers to and from the graphics device. Our GPU-based algorithm performed the ray-tracing in real-time. The strategies efficiently reduce the time consumption of memory accesses and data transfer overhead. The achieved runtimes demonstrate the viability of this approach and allow improved real-time performance for dose calculation methods in clinical routine.

use of x-ray fluorescence spectrometry to determine trace elements ...

African Journals Online (AJOL)

NIJOTECH

Abstract. This paper deals with application of X-ray fluorescence spectrometry for the detection of trace elements in graphic. An X-ray spectrometer was constructed and used to carry out measurements on graphite spheres impregnated with different chemical elements. The intensities of the lines of these trace elements, ...

Solar Proton Transport Within an ICRU Sphere Surrounded by a Complex Shield: Ray-trace Geometry

Science.gov (United States)

Slaba, Tony C.; Wilson, John W.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

2015-01-01

A computationally efficient 3DHZETRN code with enhanced neutron and light ion (Z is less than or equal to 2) propagation was recently developed for complex, inhomogeneous shield geometry described by combinatorial objects. Comparisons were made between 3DHZETRN results and Monte Carlo (MC) simulations at locations within the combinatorial geometry, and it was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in ray-trace geometry. This latest extension enables the code to be used within current engineering design practices utilizing fully detailed vehicle and habitat geometries. Through convergence testing, it is shown that fidelity in an actual shield geometry can be maintained in the discrete ray-trace description by systematically increasing the number of discrete rays used. It is also shown that this fidelity is carried into transport procedures and resulting exposure quantities without sacrificing computational efficiency.

Multiscale optical simulation settings: challenging applications handled with an iterative ray-tracing FDTD interface method.

Science.gov (United States)

Leiner, Claude; Nemitz, Wolfgang; Schweitzer, Susanne; Kuna, Ladislav; Wenzl, Franz P; Hartmann, Paul; Satzinger, Valentin; Sommer, Christian

2016-03-20

We show that with an appropriate combination of two optical simulation techniques-classical ray-tracing and the finite difference time domain method-an optical device containing multiple diffractive and refractive optical elements can be accurately simulated in an iterative simulation approach. We compare the simulation results with experimental measurements of the device to discuss the applicability and accuracy of our iterative simulation procedure.

Backward ray tracing for ultrasonic imaging

NARCIS (Netherlands)

Breeuwer, R.

1990-01-01

Focused ultrasonic beams frequently pass one or more media interfaces, strongly affecting the ultrasonic beamshape and focusing. A computer program, based on backward ray tracing was developed to compute the shape of a corrected focusing mirror. This shape is verified with another program; then the

Solar proton exposure of an ICRU sphere within a complex structure part II: Ray-trace geometry.

Science.gov (United States)

Slaba, Tony C; Wilson, John W; Badavi, Francis F; Reddell, Brandon D; Bahadori, Amir A

2016-06-01

A computationally efficient 3DHZETRN code with enhanced neutron and light ion (Z ≤ 2) propagation was recently developed for complex, inhomogeneous shield geometry described by combinatorial objects. Comparisons were made between 3DHZETRN results and Monte Carlo (MC) simulations at locations within the combinatorial geometry, and it was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in ray-trace geometry. This latest extension enables the code to be used within current engineering design practices utilizing fully detailed vehicle and habitat geometries. Through convergence testing, it is shown that fidelity in an actual shield geometry can be maintained in the discrete ray-trace description by systematically increasing the number of discrete rays used. It is also shown that this fidelity is carried into transport procedures and resulting exposure quantities without sacrificing computational efficiency. Published by Elsevier Ltd.

Electron ray tracing with high accuracy

International Nuclear Information System (INIS)

Saito, K.; Okubo, T.; Takamoto, K.; Uno, Y.; Kondo, M.

1986-01-01

An electron ray tracing program is developed to investigate the overall geometrical and chromatic aberrations in electron optical systems. The program also computes aberrations due to manufacturing errors in lenses and deflectors. Computation accuracy is improved by (1) calculating electrostatic and magnetic scalar potentials using the finite element method with third-order isoparametric elements, and (2) solving the modified ray equation which the aberrations satisfy. Computation accuracy of 4 nm is achieved for calculating optical properties of the system with an electrostatic lens

Computation and analysis of backward ray-tracing in aero-optics flow fields.

Science.gov (United States)

Xu, Liang; Xue, Deting; Lv, Xiaoyi

2018-01-08

A backward ray-tracing method is proposed for aero-optics simulation. Different from forward tracing, the backward tracing direction is from the internal sensor to the distant target. Along this direction, the tracing in turn goes through the internal gas region, the aero-optics flow field, and the freestream. The coordinate value, the density, and the refractive index are calculated at each tracing step. A stopping criterion is developed to ensure the tracing stops at the outer edge of the aero-optics flow field. As a demonstration, the analysis is carried out for a typical blunt nosed vehicle. The backward tracing method and stopping criterion greatly simplify the ray-tracing computations in the aero-optics flow field, and they can be extended to our active laser illumination aero-optics study because of the reciprocity principle.

Virtual Ray Tracing as a Conceptual Tool for Image Formation in Mirrors and Lenses

Science.gov (United States)

Heikkinen, Lasse; Savinainen, Antti; Saarelainen, Markku

2016-01-01

The ray tracing method is widely used in teaching geometrical optics at the upper secondary and university levels. However, using simple and straightforward examples may lead to a situation in which students use the model of ray tracing too narrowly. Previous studies show that students seem to use the ray tracing method too concretely instead of…

A manual to the MAXRAY program library for reflective and dispersive ray tracing

International Nuclear Information System (INIS)

Svensson, S.; Nyholm, R.

1985-07-01

A general ray tracing program package for reflective and dispersive X-ray optics is described. The package consists of a number of subroutines written in FORTRAN 77 code giving the necessary tools for ray tracing. The program package is available on request from the authors. (authors)

Quantitative trace element analysis of individual fly ash particles by means of X-ray microfluorescence

Energy Technology Data Exchange (ETDEWEB)

Vincze, L.; Somogyi, A.; Osan, J.; Vekemans, B.; Torok, S.; Janssens, K.; Adams, F. [Universitaire of Instelling Antwerp, Wilrijk (Belgium). Dept. of Chemistry

2002-07-01

A new quantification procedure was developed for the evaluation of X-ray microfluorescence (XRF) data sets obtained from individual particles, based on iterative Monte Carlo (MC) simulation. Combined with the high sensitivity of synchrotron radiation-induced XRF spectroscopy, the method was used to obtain quantitative information down to trace-level concentrations from micrometer-sized particulate matter. The detailed XRF simulation model was validated by comparison of calculated and experimental XRF spectra obtained for glass microsphere standards, resulting in uncertainties in the range of 3-10% for the calculated elemental sensitivities. The simulation model was applied for the quantitative analysis of X-ray tube and synchrotron radiation-induced scanning micro-XRF spectra of individual coal and wood fly ash particles originating from different Hungarian power plants. By measuring the same particles by both methods the major, minor, and trace element compositions of the particles were determined. The uncertainty of the MC based quantitative analysis scheme is estimated to be in the range of 5-30%.

Real-time generation of kd-trees for ray tracing using DirectX 11

OpenAIRE

Säll, Martin; Cronqvist, Fredrik

2017-01-01

Context. Ray tracing has always been a simple but effective way to create a photorealistic scene but at a greater cost when expanding the scene. Recent improvements in GPU and CPU hardware have made ray tracing faster, making more complex scenes possible with the same amount of time needed to process the scene. Despite the improvements in hardware ray tracing is still rarely run at a interactive speed. Objectives. The aim of this experiment was to implement a new kdtree generation algorithm us...

Fast solar radiation pressure modelling with ray tracing and multiple reflections

Science.gov (United States)

Li, Zhen; Ziebart, Marek; Bhattarai, Santosh; Harrison, David; Grey, Stuart

2018-05-01

Physics based SRP (Solar Radiation Pressure) models using ray tracing methods are powerful tools when modelling the forces on complex real world space vehicles. Currently high resolution (1 mm) ray tracing with secondary intersections is done on high performance computers at UCL (University College London). This study introduces the BVH (Bounding Volume Hierarchy) into the ray tracing approach for physics based SRP modelling and makes it possible to run high resolution analysis on personal computers. The ray tracer is both general and efficient enough to cope with the complex shape of satellites and multiple reflections (three or more, with no upper limit). In this study, the traditional ray tracing technique is introduced in the first place and then the BVH is integrated into the ray tracing. Four aspects of the ray tracer were tested for investigating the performance including runtime, accuracy, the effects of multiple reflections and the effects of pixel array resolution.Test results in runtime on GPS IIR and Galileo IOV (In Orbit Validation) satellites show that the BVH can make the force model computation 30-50 times faster. The ray tracer has an absolute accuracy of several nanonewtons by comparing the test results for spheres and planes with the analytical computations. The multiple reflection effects are investigated both in the intersection number and acceleration on GPS IIR, Galileo IOV and Sentinel-1 spacecraft. Considering the number of intersections, the 3rd reflection can capture 99.12 %, 99.14 % , and 91.34 % of the total reflections for GPS IIR, Galileo IOV satellite bus and the Sentinel-1 spacecraft respectively. In terms of the multiple reflection effects on the acceleration, the secondary reflection effect for Galileo IOV satellite and Sentinel-1 can reach 0.2 nm /s2 and 0.4 nm /s2 respectively. The error percentage in the accelerations magnitude results show that the 3rd reflection should be considered in order to make it less than 0.035 % . The

Fast voxel and polygon ray-tracing algorithms in intensity modulated radiation therapy treatment planning

International Nuclear Information System (INIS)

Fox, Christopher; Romeijn, H. Edwin; Dempsey, James F.

2006-01-01

We present work on combining three algorithms to improve ray-tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point-in-polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point-in-polygon and incremental voxel ray-tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray-tracing algorithms of Siddon for voxel classification (point-in-polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray-tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a 2.5 mm isotropic dose grid into 1-4 targets and 5-14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230-2400 beamlets using a finite-size pencil-beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray-tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11-25 times faster than the radial-testing beamlet extent approach and was further improved 1.7-2.0 fold through point-classification using the method of translation over the cross product technique

Three-dimensional ray tracing in spherical and elliptical generalized Luneburg lenses for application in the human eye lens.

Science.gov (United States)

Gómez-Correa, J E; Coello, V; Garza-Rivera, A; Puente, N P; Chávez-Cerda, S

2016-03-10

Ray tracing in spherical Luneburg lenses has always been represented in 2D. All propagation planes in a 3D spherical Luneburg lens generate the same ray tracing, due to its radial symmetry. A geometry without radial symmetry generates a different ray tracing. For this reason, a new ray tracing method in 3D through spherical and elliptical Luneburg lenses using 2D methods is proposed. The physics of the propagation is shown here, which allows us to make a ray tracing associated with a vortex beam. A 3D ray tracing in a composite modified Luneburg lens that represents the human eye lens is also presented.

Ray-tracing of shape metrology data of grazing incidence x-ray astronomy mirrors

Science.gov (United States)

Zocchi, Fabio E.; Vernani, Dervis

2008-07-01

A number of future X-ray astronomy missions (e.g. Simbol-X, eROSITA) plan to utilize high throughput grazing incidence optics with very lightweight mirrors. The severe mass specifications require a further optimization of the existing technology with the consequent need of proper optical numerical modeling capabilities for both the masters and the mirrors. A ray tracing code has been developed for the simulation of the optical performance of type I Wolter masters and mirrors starting from 2D and 3D metrology data. In particular, in the case of 2D measurements, a 3D data set is reconstructed on the basis of dimensional references and used for the optical analysis by ray tracing. In this approach, the actual 3D shape is used for the optical analysis, thus avoiding the need of combining the separate contributions of different 2D measurements that require the knowledge of their interactions which is not normally available. The paper describes the proposed approach and presents examples of application on a prototype engineering master in the frame of ongoing activities carried out for present and future X-ray missions.

RAY TRACING RENDER MENGGUNAKAN FRAGMENT ANTI ALIASING

Directory of Open Access Journals (Sweden)

Febriliyan Samopa

2008-07-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Rendering is generating surface and three-dimensional effects on an object displayed on a monitor screen. Ray tracing as a rendering method that traces ray for each image pixel has a drawback, that is, aliasing (jaggies effect. There are some methods for executing anti aliasing. One of those methods is OGSS (Ordered Grid Super Sampling. OGSS is able to perform aliasing well. However, this method requires more computation time since sampling of all pixels in the image will be increased. Fragment Anti Aliasing (FAA is a new alternative method that can cope with the drawback. FAA will check the image when performing rendering to a scene. Jaggies effect is only happened at curve and gradient object. Therefore, only this part of object that will experience sampling magnification. After this sampling magnification and the pixel values are computed, then downsample is performed to retrieve the original pixel values. Experimental results show that the software can implement ray tracing well in order to form images, and it can implement FAA and OGSS technique to perform anti aliasing. In general, rendering using FAA is faster than using OGSS

Microwave transport in EBT distribution manifolds using Monte Carlo ray-tracing techniques

International Nuclear Information System (INIS)

Lillie, R.A.; White, T.L.; Gabriel, T.A.; Alsmiller, R.G. Jr.

1983-01-01

Ray tracing Monte Carlo calculations have been carried out using an existing Monte Carlo radiation transport code to obtain estimates of the microsave power exiting the torus coupling links in EPT microwave manifolds. The microwave power loss and polarization at surface reflections were accounted for by treating the microwaves as plane waves reflecting off plane surfaces. Agreement on the order of 10% was obtained between the measured and calculated output power distribution for an existing EBT-S toroidal manifold. A cost effective iterative procedure utilizing the Monte Carlo history data was implemented to predict design changes which could produce increased manifold efficiency and improved output power uniformity

A comparison of three different ray trace programs for x-ray and infrared synchrotron beamline designs

International Nuclear Information System (INIS)

Irick, S.C.; Jung, C.R.

1997-07-01

There are a number of ray trace programs currently used for the design of synchrotron beamlines. While several of these programs have been written and used mostly within the programmer''s institution, many have also been available to the general public. This paper discusses three such programs. One is a commercial product oriented for the general optical designer (not specifically for synchrotron beamlines). One is designed for synchrotron beamlines and is free with restricted availability. Finally, one is designed for synchrotron beamlines and is used primarily in one institution. The wealth of information from general optical materials and components catalogs is readily available in the commercial program for general optical designs. This makes the design of an infrared beamline easier from the standpoint of component selection. However, this program is not easily configured for synchrotron beamline designs, particularly for a bending magnet source. The synchrotron ray trace programs offer a variety of sources, but generally are not as easy to use from the standpoint of the user interface. This paper shows ray traces of the same beamline Optikwerks, SHADOW, and RAY, and compares the results

Simulations Of Neutron Beam Optic For Neutron Radiography Collimator Using Ray Tracing Methodology

International Nuclear Information System (INIS)

Norfarizan Mohd Said; Muhammad Rawi Mohamed Zin

2014-01-01

Ray- tracing is a technique for simulating the performance of neutron instruments. McStas, the open-source software package based on a meta-language, is a tool for carrying out ray-tracing simulations. The program has been successfully applied in investigating neutron guide design, flux optimization and other related areas with high complexity and precision. The aim of this paper is to discuss the implementation of ray-tracing technique with McStas for simulating the performance of neutron collimation system developed for imaging system of TRIGA RTP reactor. The code for the simulation was developed and the results are presented. The analysis of the performance is reported and discussed. (author)

High-efficiency photorealistic computer-generated holograms based on the backward ray-tracing technique

Science.gov (United States)

Wang, Yuan; Chen, Zhidong; Sang, Xinzhu; Li, Hui; Zhao, Linmin

2018-03-01

Holographic displays can provide the complete optical wave field of a three-dimensional (3D) scene, including the depth perception. However, it often takes a long computation time to produce traditional computer-generated holograms (CGHs) without more complex and photorealistic rendering. The backward ray-tracing technique is able to render photorealistic high-quality images, which noticeably reduce the computation time achieved from the high-degree parallelism. Here, a high-efficiency photorealistic computer-generated hologram method is presented based on the ray-tracing technique. Rays are parallelly launched and traced under different illuminations and circumstances. Experimental results demonstrate the effectiveness of the proposed method. Compared with the traditional point cloud CGH, the computation time is decreased to 24 s to reconstruct a 3D object of 100 ×100 rays with continuous depth change.

ARTEAM - Advanced ray tracing with earth atmospheric models

NARCIS (Netherlands)

Kunz, G.J.; Moerman, M.M.; Eijk, A.M.J. van

2002-01-01

The Advanced Ray Tracing with Earth Atmospheric Models (ARTEAM) aims at a description of the electro-optical propagation environment in the marine atmospheric surface layer. For given meteorological conditions, the model evaluates height- and range-resolved transmission losses, refraction and

Usage of ray tracing transfer matrix to mitigate the stray light for ITER spectroscopy

International Nuclear Information System (INIS)

Kajita, S.; Veshchev, E.; Barnsley, R.; Walsh, M.

2016-01-01

Stray light formed by the reflection of photons on inner wall from a bright divertor region can be a serious issue in spectroscopic measurement systems in ITER. In this study, we propose a method to mitigate the influence of stray light using a ray tracing analysis. Usually, a ray tracing simulation requires a time consuming runs. We constructed transfer matrices based on the ray tracing simulation results and used them to demonstrate the influence of stray light. It is shown that the transfer matrix can be used to reconstruct the emission profile by considering the influence of the stray light without any additional ray tracing runs. Mitigation of the stray light in ITER divertor impurity monitor was demonstrated, and a method of prediction of the stray light level for the scrape off layer spectroscopy from divertor region was proposed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of trace metals in sea waters of the albanian coast by energy-dispersive x-ray fluorescence

International Nuclear Information System (INIS)

Civici, N.

1994-01-01

Preconcentration of trace transition and heavy metal ions by precipitation with APDC has been combined with energy-dispersive X-ray fluorescence for environmental sea water analysis. The preconcentration procedure implies adding of 500 μg Mo ion and 10 ml of 1 % water solution of APDC to a 500 ml water sample at pH 4, filtering off on a Millipore filter and analyzing after drying. Realistic detection limits are at 1 μg * l -1 level and precision varies between 10 - 25% at about 5 μg * l -1 level, depending on the element. Eleven sea water samples, covering Albanian Adriatic and Ionian coast, are analyzed for trace metal ions. (author) 8 refs.; 2 figs.; 5 tabs

Parallel ray tracing for one-dimensional discrete ordinate computations

International Nuclear Information System (INIS)

Jarvis, R.D.; Nelson, P.

1996-01-01

The ray-tracing sweep in discrete-ordinates, spatially discrete numerical approximation methods applied to the linear, steady-state, plane-parallel, mono-energetic, azimuthally symmetric, neutral-particle transport equation can be reduced to a parallel prefix computation. In so doing, the often severe penalty in convergence rate of the source iteration, suffered by most current parallel algorithms using spatial domain decomposition, can be avoided while attaining parallelism in the spatial domain to whatever extent desired. In addition, the reduction implies parallel algorithm complexity limits for the ray-tracing sweep. The reduction applies to all closed, linear, one-cell functional (CLOF) spatial approximation methods, which encompasses most in current popular use. Scalability test results of an implementation of the algorithm on a 64-node nCube-2S hypercube-connected, message-passing, multi-computer are described. (author)

Technical Note: A direct ray-tracing method to compute integral depth dose in pencil beam proton radiography with a multilayer ionization chamber.

Science.gov (United States)

Farace, Paolo; Righetto, Roberto; Deffet, Sylvain; Meijers, Arturs; Vander Stappen, Francois

2016-12-01

To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45 × 45 mm 2 field-of-view) of 9 × 9 spots capable of crossing the phantoms (210 MeV). The exit beam was collected by a MLIC to sample the integral depth dose (IDD MLIC ). PRs of an electron-density and of a head phantom were acquired by moving the couch to obtain multiple 45 × 45 mm 2 frames. To map the corresponding range errors, the two-dimensional set of IDD MLIC was compared with (i) the integral depth dose computed by the treatment planning system (TPS) by both analytic (IDD TPS ) and Monte Carlo (IDD MC ) algorithms in a volume of water simulating the MLIC at the CT, and (ii) the integral depth dose directly computed by a simple ray-tracing algorithm (IDD direct ) through the same CT data. The exact spatial position of the spot pattern was numerically adjusted testing different in-plane positions and selecting the one that minimized the range differences between IDD direct and IDD MLIC . Range error mapping was feasible by both the TPS and the ray-tracing methods, but very sensitive to even small misalignments. In homogeneous regions, the range errors computed by the direct ray-tracing algorithm matched the results obtained by both the analytic and the Monte Carlo algorithms. In both phantoms, lateral heterogeneities were better modeled by the ray-tracing and the Monte Carlo algorithms than by the analytic TPS computation. Accordingly, when the pencil beam crossed lateral heterogeneities, the range errors mapped by the direct algorithm matched better the Monte Carlo maps than those obtained by the analytic algorithm. Finally, the simplicity of the ray-tracing algorithm allowed to implement a prototype procedure for automated spatial alignment. The ray-tracing algorithm can reliably replace the TPS method in MLIC PR for in

Real time ray tracing of skeletal implicit surfaces

DEFF Research Database (Denmark)

Rouiller, Olivier; Bærentzen, Jakob Andreas

Modeling and rendering in real time is usually done via rasterization of polygonal meshes. We present a method to model with skeletal implicit surfaces and an algorithm to ray trace these surfaces in real time in the GPU. Our skeletal representation of the surfaces allows to create smooth models...

Sample handling and chemical procedures for efficacious trace analysis of urine by neutron activation analysis

International Nuclear Information System (INIS)

Blotcky, A.J.; Rack, E.P.; Roman, F.R.

1988-01-01

Important for the determination of trace elements, ions, or compounds in urine by chemical neutron activation analysis is the optimization of sample handling, preirradiation chemistry, and radioassay procedures necessary for viable analysis. Each element, because of its natural abundance in the earth's crust and, hence, its potential for reagent and environmental contamination, requires specific procedures for storage, handling, and preirradiation chemistry. Radioassay techniques for radionuclides vary depending on their half-lives and decay characteristics. Described in this paper are optimized procedures for aluminum and selenium. While 28 Al (T 1/2 = 2.24 min) and 77m Se(T 1/2 = 17.4s) have short half-lives, their gamma-ray spectra are quite different. Aluminum-28 decays by a 1779-keV gamma and 77m Se by a 162-keV gamma. Unlike selenium, aluminum is a ubiquitous element in the environment requiring special handling to minimize contamination in all phases of its analytical determination

Random ray-tracing and graphic analysing of charged particle trajectories

International Nuclear Information System (INIS)

Lin Xiaomei; Mao Naifeng; Chen Jingxian

1990-01-01

In order to describe the optical properties of a charged particle beam realistically, the random sampling of initial conditions of particles in ray-tracing is discussed. The emission surface of particles may be a plane, a cylindrical surface or a spherical surface. The distribution functions may be expressed analytically or numerically. In order to analyse the properties of the charged particle beam systematically by use of the results from ray-tracing efficiently, the graphic processing and analysing of particle trajectories are also discussed, including the spline function fitting of trajectories, the graphic drafting of trajectories and beam envelopes, the determining of image dimensions and the correspinding positions, and also the graphic drafting of particle distributions on arbitrary cross sections

Trace element analysis in liquids by proton induced x-ray emission

International Nuclear Information System (INIS)

Deconninck, G.

Proton induced x-ray emission (PIXE) from liquid has been developed for quantitative and simultaneous analysis of trace elements. Liquid drops and trickles are bombarded at atmospheric pressure, x-rays are detected in a non dispersive Si(Li) solid state detector. Absolute determinations are made by comparison with standard solutions. Detection limits in a 5 minutes run are in the ppm range for a single drop (0.05 ml). The application of this technique to the determination of trace elements in biological liquids is investigated (Cr, Mn, Fe, Co, Ni, Cu, Zn, in plant extracts, haemocyanine, albumins...). (author)

Neutron transport study based on assembly modular ray tracing MOC method

International Nuclear Information System (INIS)

Tian Chao; Zheng Youqi; Li Yunzhao; Li Shuo; Chai Xiaoming

2015-01-01

It is difficulty for the MOC method based on Cell Modular Ray Tracing to deal with the irregular geometry such as the water gap between the PWR lattices. Hence, the neutron transport code NECP-Medlar based on Assembly Modular Ray Tracing is developed. CMFD method is used to accelerate the transport calculation. The numerical results of the 2D C5G7 benchmark and typical PWR lattice prove that NECP-Medlar has an excellent performance in terms of accuracy and efficiency. Besides, NECP-Medlar can describe clearly the flux distribution of the lattice with water gap. (authors)

Ray tracing study of rising tone EMIC-triggered emissions

Science.gov (United States)

Hanzelka, Miroslav; Santolík, Ondřej; Grison, Benjamin; Cornilleau-Wehrlin, Nicole

2017-04-01

ElectroMagnetic Ion Cyclotron (EMIC) triggered emissions have been subject of extensive theoretical and experimental research in last years. These emissions are characterized by high coherence values and a frequency range of 0.5 - 2.0 Hz, close to local helium gyrofrequency. We perform ray tracing case studies of rising tone EMIC-triggered emissions observed by the Cluster spacecraft in both nightside and dayside regions off the equatorial plane. By comparison of simulated and measured wave properties, namely wave vector orientation, group velocity, dispersion and ellipticity of polarization, we determine possible source locations. Diffusive equilibrium density model and other, semi-empirical models are used with ion composition inferred from cross-over frequencies. Ray tracing simulations are done in cold plasma approximation with inclusion of Landau and cyclotron damping. Various widths, locations and profiles of plasmapause are tested.

2-Dimensional B-Spline Algorithms with Applications to Ray Tracing in Media of Spatially-Varying Refractive Index

Science.gov (United States)

2007-08-01

In the approach, photon trajectories are computed using a solution of the Eikonal equation (ray-tracing methods) rather than linear trajectories. The...coupling the radiative transport solution into heat transfer and damage models. 15. SUBJECT TERMS: B-Splines, Ray-Tracing, Eikonal Equation...multi-layer biological tissue model. In the approach, photon trajectories are computed using a solution of the Eikonal equation (ray-tracing methods

A comparison of pecking generated by serial, delay, and trace autoshaping procedures1

Science.gov (United States)

Newlin, Robert J.; LoLordo, Vincent M.

1976-01-01

Pigeons were exposed to serial, delay, and trace autoshaping procedures. In Experiment I, all conditioned stimuli (CSs) were changes in illumination of the response key. The number of trials to acquisition of the keypeck increased from serial, to 4-sec delay, 8-sec delay, and 8-sec trace procedures, in that order. In Experiment II, which used a longer intertrial interval, trials to criterion increased from 8-sec delay, to 28-sec delay, 8-sec trace, and 28-sec trace procedures, in that order. In Experiment III, two groups received serial procedures in which the first CS was either a tone or a houselight, and the second was a keylight. The tone group acquired the key peck more rapidly than the houselight group. Early in conditioning in these experiments, and when the conditioned stimulus was a change in the keylight, there was a short latency to the onset of pecking and pecking was directed at the CS. After extensive conditioning, or when the CS was relatively diffuse, pecking still occurred, but had a longer latency and was not reliably directed toward the conditioned stimulus. PMID:16811907

Rapid simulation of X-ray transmission imaging for baggage inspection via GPU-based ray-tracing

Science.gov (United States)

Gong, Qian; Stoian, Razvan-Ionut; Coccarelli, David S.; Greenberg, Joel A.; Vera, Esteban; Gehm, Michael E.

2018-01-01

We present a pipeline that rapidly simulates X-ray transmission imaging for arbitrary system architectures using GPU-based ray-tracing techniques. The purpose of the pipeline is to enable statistical analysis of threat detection in the context of airline baggage inspection. As a faster alternative to Monte Carlo methods, we adopt a deterministic approach for simulating photoelectric absorption-based imaging. The highly-optimized NVIDIA OptiX API is used to implement ray-tracing, greatly speeding code execution. In addition, we implement the first hierarchical representation structure to determine the interaction path length of rays traversing heterogeneous media described by layered polygons. The accuracy of the pipeline has been validated by comparing simulated data with experimental data collected using a heterogenous phantom and a laboratory X-ray imaging system. On a single computer, our approach allows us to generate over 400 2D transmission projections (125 × 125 pixels per frame) per hour for a bag packed with hundreds of everyday objects. By implementing our approach on cloud-based GPU computing platforms, we find that the same 2D projections of approximately 3.9 million bags can be obtained in a single day using 400 GPU instances, at a cost of only 0.001 per bag.

Implementation of Refined Ray Tracing inside a Space Module

Directory of Open Access Journals (Sweden)

Balamati Choudhury

2012-08-01

Full Text Available Modern space modules are susceptible to EM radiation from both external and internal sources within the space module. Since the EM waves for various operations are frequently in the high-frequency domain, asymptotic raytheoretic methods are often the most optimal choice for deterministic EM field analysis. In this work, surface modeling of a typical manned space module is done by hybridizing a finite segment of right circular cylinder and a general paraboloid of revolution (GPOR frustum. A transmitting source is placed inside the space module and test rays are launched from the transmitter. The rays are allowed to propagate inside the cavity. Unlike the available ray-tracing package, that use numerical search methods, a quasi-analytical ray-propagation model is developed to obtain the ray-path details inside the cavity which involves the ray-launching, ray-bunching, and an adaptive cube for ray-reception.

SU-F-T-555: Accurate Stereotactic Cone TMRs Converted from PDDs Scanned with Ray Trace

International Nuclear Information System (INIS)

Li, H; Zhong, H; Qin, Y; Snyder, K; Chetty, I; Wen, N

2016-01-01

Purpose: To investigate whether the accuracy of TMRs for stereotactic cones converted from PDDs scanned with Ray Trace can be improved, when compared against the TMRs converted from the traditional PDDs. Methods: Ray Trace measurement in Sun Nuclear 3D Scanner is for accurate scan of small field PDDs. The system detects the center of field at two depths, for example, at 3 and 20 cm in our study, and then performs scan along the line passing the two centers. With both Ray Trace and the traditional method, PDDs for conical cones of 4, 5, 7.5, 10, 12.5, 15, and 17.5 mm diameter (jaws set to 5×5 cm) were obtained for 6X FFF and 10X FFF energies on a Varian Edge linac, using Edge detectors. The formalism of converting PDD to TMR given in Khan’s book (4th Edition, p.161) was applied. Sp values at dmax were obtained by measuring cone Scp and Sc. Continuous direct measurement of TMR by filling/draining water to/from the tank and spot measurement by moving the tank and detector were also performed with the same equipment, using 100 cm SDD. Results: For 6XFFF energy and all the cones, TMRs converted from Ray Trace were very close to the continuous and spot measurement, while TMRs converted from traditional PDDs had larger deviation. Along the central axis beyond dmax, 1.7% of TMR data points calculated from Ray Trace had more 3% deviation from measurement, with maximal deviation of 5.2%. Whereas, 34% of TMR points calculated from traditional PDDs had more than 3% deviation, with maximum of 5.7%. In this initial study, Ray Trace scans for 10XFFF beam were noisy, further measurement is warranted. Conclusion: The Ray Trace could improve the accuracy of PDDs measurement and the calculated TMRs for stereotactic cones, which was within 3% of the measured TMRs.

SU-F-T-555: Accurate Stereotactic Cone TMRs Converted from PDDs Scanned with Ray Trace

Energy Technology Data Exchange (ETDEWEB)

Li, H; Zhong, H; Qin, Y; Snyder, K; Chetty, I; Wen, N [Henry Ford Health System, Detroit, MI (United States)

2016-06-15

Purpose: To investigate whether the accuracy of TMRs for stereotactic cones converted from PDDs scanned with Ray Trace can be improved, when compared against the TMRs converted from the traditional PDDs. Methods: Ray Trace measurement in Sun Nuclear 3D Scanner is for accurate scan of small field PDDs. The system detects the center of field at two depths, for example, at 3 and 20 cm in our study, and then performs scan along the line passing the two centers. With both Ray Trace and the traditional method, PDDs for conical cones of 4, 5, 7.5, 10, 12.5, 15, and 17.5 mm diameter (jaws set to 5×5 cm) were obtained for 6X FFF and 10X FFF energies on a Varian Edge linac, using Edge detectors. The formalism of converting PDD to TMR given in Khan’s book (4th Edition, p.161) was applied. Sp values at dmax were obtained by measuring cone Scp and Sc. Continuous direct measurement of TMR by filling/draining water to/from the tank and spot measurement by moving the tank and detector were also performed with the same equipment, using 100 cm SDD. Results: For 6XFFF energy and all the cones, TMRs converted from Ray Trace were very close to the continuous and spot measurement, while TMRs converted from traditional PDDs had larger deviation. Along the central axis beyond dmax, 1.7% of TMR data points calculated from Ray Trace had more 3% deviation from measurement, with maximal deviation of 5.2%. Whereas, 34% of TMR points calculated from traditional PDDs had more than 3% deviation, with maximum of 5.7%. In this initial study, Ray Trace scans for 10XFFF beam were noisy, further measurement is warranted. Conclusion: The Ray Trace could improve the accuracy of PDDs measurement and the calculated TMRs for stereotactic cones, which was within 3% of the measured TMRs.

TIM, a ray-tracing program for METATOY research and its dissemination

Science.gov (United States)

Lambert, Dean; Hamilton, Alasdair C.; Constable, George; Snehanshu, Harsh; Talati, Sharvil; Courtial, Johannes

2012-03-01

TIM (The Interactive METATOY) is a ray-tracing program specifically tailored towards our research in METATOYs, which are optical components that appear to be able to create wave-optically forbidden light-ray fields. For this reason, TIM possesses features not found in other ray-tracing programs. TIM can either be used interactively or by modifying the openly available source code; in both cases, it can easily be run as an applet embedded in a web page. Here we describe the basic structure of TIM's source code and how to extend it, and we give examples of how we have used TIM in our own research. Program summaryProgram title: TIM Catalogue identifier: AEKY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License No. of lines in distributed program, including test data, etc.: 124 478 No. of bytes in distributed program, including test data, etc.: 4 120 052 Distribution format: tar.gz Programming language: Java Computer: Any computer capable of running the Java Virtual Machine (JVM) 1.6 Operating system: Any; developed under Mac OS X Version 10.6 RAM: Typically 145 MB (interactive version running under Mac OS X Version 10.6) Classification: 14, 18 External routines: JAMA [1] (source code included) Nature of problem: Visualisation of scenes that include scene objects that create wave-optically forbidden light-ray fields. Solution method: Ray tracing. Unusual features: Specifically designed to visualise wave-optically forbidden light-ray fields; can visualise ray trajectories; can visualise geometric optic transformations; can create anaglyphs (for viewing with coloured "3D glasses") and random-dot autostereograms of the scene; integrable into web pages. Running time: Problem-dependent; typically seconds for a simple scene.

Ray tracing of auroral Z mode radiation, AKR and auroral hiss

International Nuclear Information System (INIS)

Horne, R.B.; Jones, D.; Kimura, I.; Sawada, A.

1990-01-01

While observed frequency bandwidths of auroral Z mode radiation cannot be directly accounted for in terms of direct cyclotron maser instability generation, ray tracing in a hot plasma indicates that if the radiation near a plasma frequency lower than the gyrofrequency, the observed bandwidths are explainable in terms of upward propagation away from the earth. An auroral Z-mode generation mechanism is proposed involving mode conversion from O-mode auroral kilometric radiation (AKR) at the plasma frequency, as well as mode conversion from upgoing auroral hiss. Ray tracings in the O mode identify a possible AKR source region along L = 8.55. 11 refs

ACCELERATION RENDERING METHOD ON RAY TRACING WITH ANGLE COMPARISON AND DISTANCE COMPARISON

Directory of Open Access Journals (Sweden)

Liliana liliana

2007-01-01

Full Text Available In computer graphics applications, to produce realistic images, a method that is often used is ray tracing. Ray tracing does not only model local illumination but also global illumination. Local illumination count ambient, diffuse and specular effects only, but global illumination also count mirroring and transparency. Local illumination count effects from the lamp(s but global illumination count effects from other object(s too. Objects that are usually modeled are primitive objects and mesh objects. The advantage of mesh modeling is various, interesting and real-like shape. Mesh contains many primitive objects like triangle or square (rare. A problem in mesh object modeling is long rendering time. It is because every ray must be checked with a lot of triangle of the mesh. Added by ray from other objects checking, the number of ray that traced will increase. It causes the increasing of rendering time. To solve this problem, in this research, new methods are developed to make the rendering process of mesh object faster. The new methods are angle comparison and distance comparison. These methods are used to reduce the number of ray checking. The rays predicted will not intersect with the mesh, are not checked weather the ray intersects the mesh. With angle comparison, if using small angle to compare, the rendering process will be fast. This method has disadvantage, if the shape of each triangle is big, some triangles will be corrupted. If the angle to compare is bigger, mesh corruption can be avoided but the rendering time will be longer than without comparison. With distance comparison, the rendering time is less than without comparison, and no triangle will be corrupted.

Proton induced X-Ray fluorescence study as a tool trace element analysis

International Nuclear Information System (INIS)

El-Kady, Ahmed A.

1978-01-01

Usefulness and limitations of trace elemental analysis by high energy charged particles and photon induced X-ray have been discussed. Comparison with the well established neutron activation analysis technique is also given. Back-ground radiation due to bremsstrahlung from secondary electrons and due to charged particle bremsstrahlung have been reviewed for different projectiles. The sensitivity of elemental analysis by proton induced X-ray fluorescence have been examined by measuring the characteristic X-ray emission cross section for K and L transitions of many elements and for different proton energies and compared with theroretical values. The discussion given in this report show that with suitable proton generator and a high resolution X-ray detector, proton X-ray fluorescence technique is capable of analyzing many elements simultaneously at the part per million level and offers a rapid and reliable method for trace element analysis. Data on water, blood and tissue samples given in this report are few examples of many possible applications

The Use of Pro/Engineer CAD Software and Fishbowl Tool Kit in Ray-tracing Analysis

Science.gov (United States)

Nounu, Hatem N.; Kim, Myung-Hee Y.; Ponomarev, Artem L.; Cucinotta, Francis A.

2009-01-01

This document is designed as a manual for a user who wants to operate the Pro/ENGINEER (ProE) Wildfire 3.0 with the NASA Space Radiation Program's (SRP) custom-designed Toolkit, called 'Fishbowl', for the ray tracing of complex spacecraft geometries given by a ProE CAD model. The analysis of spacecraft geometry through ray tracing is a vital part in the calculation of health risks from space radiation. Space radiation poses severe risks of cancer, degenerative diseases and acute radiation sickness during long-term exploration missions, and shielding optimization is an important component in the application of radiation risk models. Ray tracing is a technique in which 3-dimensional (3D) vehicle geometry can be represented as the input for the space radiation transport code and subsequent risk calculations. In ray tracing a certain number of rays (on the order of 1000) are used to calculate the equivalent thickness, say of aluminum, of the spacecraft geometry seen at a point of interest called the dose point. The rays originate at the dose point and terminate at a homogenously distributed set of points lying on a sphere that circumscribes the spacecraft and that has its center at the dose point. The distance a ray traverses in each material is converted to aluminum or other user-selected equivalent thickness. Then all equivalent thicknesses are summed up for each ray. Since each ray points to a direction, the aluminum equivalent of each ray represents the shielding that the geometry provides to the dose point from that particular direction. This manual will first list for the user the contact information for help in installing ProE and Fishbowl in addition to notes on the platform support and system requirements information. Second, the document will show the user how to use the software to ray trace a Pro/E-designed 3-D assembly and will serve later as a reference for troubleshooting. The user is assumed to have previous knowledge of ProE and CAD modeling.

Vertex shading of the three-dimensional model based on ray-tracing algorithm

Science.gov (United States)

Hu, Xiaoming; Sang, Xinzhu; Xing, Shujun; Yan, Binbin; Wang, Kuiru; Dou, Wenhua; Xiao, Liquan

2016-10-01

Ray Tracing Algorithm is one of the research hotspots in Photorealistic Graphics. It is an important light and shadow technology in many industries with the three-dimensional (3D) structure, such as aerospace, game, video and so on. Unlike the traditional method of pixel shading based on ray tracing, a novel ray tracing algorithm is presented to color and render vertices of the 3D model directly. Rendering results are related to the degree of subdivision of the 3D model. A good light and shade effect is achieved by realizing the quad-tree data structure to get adaptive subdivision of a triangle according to the brightness difference of its vertices. The uniform grid algorithm is adopted to improve the rendering efficiency. Besides, the rendering time is independent of the screen resolution. In theory, as long as the subdivision of a model is adequate, cool effects as the same as the way of pixel shading will be obtained. Our practical application can be compromised between the efficiency and the effectiveness.

Ray tracing the Wigner distribution function for optical simulations

NARCIS (Netherlands)

Mout, B.M.; Wick, Michael; Bociort, F.; Petschulat, Joerg; Urbach, Paul

2018-01-01

We study a simulation method that uses the Wigner distribution function to incorporate wave optical effects in an established framework based on geometrical optics, i.e., a ray tracing engine. We use the method to calculate point spread functions and show that it is accurate for paraxial systems

Three-dimensional ray-tracing model for the study of advanced refractive errors in keratoconus.

Science.gov (United States)

Schedin, Staffan; Hallberg, Per; Behndig, Anders

2016-01-20

We propose a numerical three-dimensional (3D) ray-tracing model for the analysis of advanced corneal refractive errors. The 3D modeling was based on measured corneal elevation data by means of Scheimpflug photography. A mathematical description of the measured corneal surfaces from a keratoconus (KC) patient was used for the 3D ray tracing, based on Snell's law of refraction. A model of a commercial intraocular lens (IOL) was included in the analysis. By modifying the posterior IOL surface, it was shown that the imaging quality could be significantly improved. The RMS values were reduced by approximately 50% close to the retina, both for on- and off-axis geometries. The 3D ray-tracing model can constitute a basis for simulation of customized IOLs that are able to correct the advanced, irregular refractive errors in KC.

Ray-tracing toroidal axisymmetric devices. 1. theoretical analysis

International Nuclear Information System (INIS)

Cardinali, A.; Brambilla, M.

1981-06-01

Ray tracing technique for lower hybrid waves is used to obtain informations about accessibility, power deposition profiles and eventually electric field distribution. In the first part a critical discussion to establish the meaning and validity of this technique is presented, while in the second part of this work applications to small and to large, fat tokamaks are presented, which support and explain the theoretical arguments

PEMBUATAN PERANGKAT LUNAK UNTUK MEMVISUALISASIKAN BENDA TEMBUS PANDANG DENGAN METODE RAY TRACING

Directory of Open Access Journals (Sweden)

Liliana Liliana

2004-01-01

Full Text Available Today computer graphics is used in many aspects, especially to make animation, advertisement and game. We hope this technology can produce realistic pictures which same quality with photo. Metode to get the realistic 3D image is ray tracing. In this journal, make a software which can produce realistic 3D image, especially for reflective and transparent object. Reflective object will modeled can reflect another object surrounding it. And transparent object will modeled can produce caustic effect, that's rays which refract in one area. So that area will appear brighter than area surround it. Abstract in Bahasa Indonesia : Dewasa ini grafika komputer semakin banyak digunakan di berbagai bidang terutama untuk pembuatan film animasi, iklan dan pembuatan game. Diharapkan teknologi grafika komputer mampu menghasilkan gambar-gambar realistik yang kualitasnya sama dengan kualitas foto. Salah satu metode yang digunakan untuk menghasilkan gambar 3D yang realistik tersebut adalah metode ray tracing. Dalam penelitian ini dibuat perangkat lunak yang mampu menghasilkan gambar-gambar 3D yang realistik terutama untuk benda-benda yang mengkilap dan benda-benda transparan. Benda mengkilap yang dimodelkan bisa memantulkan bayangan benda lain yang berada di sekitarnya. Benda transparan yang dimodelkan adalah benda transparan yang menghasilkan efek kaustik, yaitu pembiasan sinar dari sumber cahaya yang mengumpul di suatu daerah sehingga pada daerah tersebut akan tampak lebih terang daripada daerah sekitarnya. Kata kunci: efek kaustik, ray tracing.

Invisibility cloaking via non-smooth transformation optics and ray tracing

International Nuclear Information System (INIS)

Crosskey, Miles M.; Nixon, Andrew T.; Schick, Leland M.; Kovacic, Gregor

2011-01-01

We present examples of theoretically-predicted invisibility cloaks with shapes other than spheres and cylinders, including cones and ellipsoids, as well as shapes spliced from parts of these simpler shapes. In addition, we present an example explicitly displaying the non-uniqueness of invisibility cloaks of the same shape. We depict rays propagating through these example cloaks using ray tracing for geometric optics. - Highlights: → Theoretically-predicted conical and ellipsoidal invisibility cloaks. → Non-smooth cloaks spliced from parts of simpler shapes. → Example displaying non-uniqueness of invisibility cloaks of the same shape. → Rays propagating through example cloaks depicted using geometric optics.

SOLFAST, a Ray-Tracing Monte-Carlo software for solar concentrating facilities

International Nuclear Information System (INIS)

Roccia, J P; Piaud, B; Coustet, C; Caliot, C; Guillot, E; Flamant, G; Delatorre, J

2012-01-01

In this communication, the software SOLFAST is presented. It is a simulation tool based on the Monte-Carlo method and accelerated Ray-Tracing techniques to evaluate efficiently the energy flux in concentrated solar installations.

Development of Extended Ray-tracing method including diffraction, polarization and wave decay effects

Science.gov (United States)

Yanagihara, Kota; Kubo, Shin; Dodin, Ilya; Nakamura, Hiroaki; Tsujimura, Toru

2017-10-01

Geometrical Optics Ray-tracing is a reasonable numerical analytic approach for describing the Electron Cyclotron resonance Wave (ECW) in slowly varying spatially inhomogeneous plasma. It is well known that the result with this conventional method is adequate in most cases. However, in the case of Helical fusion plasma which has complicated magnetic structure, strong magnetic shear with a large scale length of density can cause a mode coupling of waves outside the last closed flux surface, and complicated absorption structure requires a strong focused wave for ECH. Since conventional Ray Equations to describe ECW do not have any terms to describe the diffraction, polarization and wave decay effects, we can not describe accurately a mode coupling of waves, strong focus waves, behavior of waves in inhomogeneous absorption region and so on. For fundamental solution of these problems, we consider the extension of the Ray-tracing method. Specific process is planned as follows. First, calculate the reference ray by conventional method, and define the local ray-base coordinate system along the reference ray. Then, calculate the evolution of the distributions of amplitude and phase on ray-base coordinate step by step. The progress of our extended method will be presented.

RAY: a ray tracing program in cold magnetized plasma

International Nuclear Information System (INIS)

Montes, A.; Souza, L.H.

1985-01-01

This report deals with the development of a ray tracing program, that is, the plot of an electromagnetic wave path in a cold magnetized plasma medium. The program was developed based on the validity of the geometrical optics laws to calculate the electromagnetic wave trajectory. This approximation is valid when the wave length is much smaller than the characteristic length of the medium. No hypothesis was made about a particular geometric configuration for the magnetic field, what enables the use of the program in any magnetic confinment scheme. The numerically obtained results were compared with an analytic solution for a particular case (cylindrically symmetric medium, uniform magnetostatic, field along the symmetry axis and ordinary wave) and have shown a satisfactory precision. (Author) [pt

Comparison between ray-tracing and physical optics for the computation of light absorption in capillaries--the influence of diffraction and interference.

Science.gov (United States)

Qin, Yuan; Michalowski, Andreas; Weber, Rudolf; Yang, Sen; Graf, Thomas; Ni, Xiaowu

2012-11-19

Ray-tracing is the commonly used technique to calculate the absorption of light in laser deep-penetration welding or drilling. Since new lasers with high brilliance enable small capillaries with high aspect ratios, diffraction might become important. To examine the applicability of the ray-tracing method, we studied the total absorptance and the absorbed intensity of polarized beams in several capillary geometries. The ray-tracing results are compared with more sophisticated simulations based on physical optics. The comparison shows that the simple ray-tracing is applicable to calculate the total absorptance in triangular grooves and in conical capillaries but not in rectangular grooves. To calculate the distribution of the absorbed intensity ray-tracing fails due to the neglected interference, diffraction, and the effects of beam propagation in the capillaries with sub-wavelength diameter. If diffraction is avoided e.g. with beams smaller than the entrance pupil of the capillary or with very shallow capillaries, the distribution of the absorbed intensity calculated by ray-tracing corresponds to the local average of the interference pattern found by physical optics.

Tracing contacts of TB patients in Malaysia: costs and practicality.

Science.gov (United States)

Atif, Muhammad; Sulaiman, Syed Azhar Syed; Shafie, Asrul Akmal; Ali, Irfhan; Asif, Muhammad

2012-01-01

Tuberculin skin testing (TST) and chest X-ray are the conventional methods used for tracing suspected tuberculosis (TB) patients. The purpose of the study was to calculate the cost incurred by Penang General Hospital on performing one contact tracing procedure using an activity based costing approach. Contact tracing records (including the demographic profile of contacts and outcome of the contact tracing procedure) from March 2010 until February 2011 were retrospectively obtained from the TB contact tracing record book. The human resource cost was calculated by multiplying the mean time spent (in minutes) by employees doing a specific activity by their per-minute salaries. The costs of consumables, Purified Protein Derivative vials and clinical equipment were obtained from the procurement section of the Pharmacy and Radiology Departments. The cost of the building was calculated by multiplying the area of space used by the facility with the unit cost of the public building department. Straight-line deprecation with a discount rate of 3% was assumed for the calculation of equivalent annual costs for the building and machines. Out of 1024 contact tracing procedures, TST was positive (≥10 mm) in 38 suspects. However, chemoprophylaxis was started in none. Yield of contact tracing (active tuberculosis) was as low as 0.5%. The total unit cost of chest X-ray and TST was MYR 9.23 (2.90 USD) & MYR 11.80 (USD 3.70), respectively. The total cost incurred on a single contact tracing procedure was MYR 21.03 (USD 6.60). Our findings suggest that the yield of contact tracing was very low which may be attributed to an inappropriate prioritization process. TST may be replaced with more accurate and specific methods (interferon gamma release assay) in highly prioritized contacts; or TST-positive contacts should be administered 6H therapy (provided that the chest radiography excludes TB) in accordance with standard protocols. The unit cost of contact tracing can be significantly

Evaluation of some procedures relevant to the determination of trace elemental components in biological materials by destructive neutron activation analysis

International Nuclear Information System (INIS)

Berry, D.L.

1979-01-01

The development of a simplified procedure for the analysis of biological materials by destructive neutron activation analysis (DNAA) is described. The sample manipulations preceding gamma ray assay were investigated as five specific stages of processing: (1) pre-irradiation treatment; (2) sample irradiation; (3) removal of the organic matrix; (4) removal of interfering radioactivities; and (5) concentration and separation of analyte activities. Each stage was evaluated with respect to susceptibility to sample contamination, loss of trace elemental components, and compatibility with other operations in the overall DNAA procedures. A complete DNAA procedure was proposed and evaluated for the analysis of standard bovine liver and blood samples. The DNAA system was effective for the determination of As, Cu, Fe, Hg, Mo, Rb, Sb, Se, and Zn without yield determinations and with a minimum turn-around time of approximately 3 days

Evaluation of some procedures relevant to the determination of trace elemental components in biological materials by destructive neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Berry, D.L.

1979-01-01

The development of a simplified procedure for the analysis of biological materials by destructive neutron activation analysis (DNAA) is described. The sample manipulations preceding gamma ray assay were investigated as five specific stages of processing: (1) pre-irradiation treatment; (2) sample irradiation; (3) removal of the organic matrix; (4) removal of interfering radioactivities; and (5) concentration and separation of analyte activities. Each stage was evaluated with respect to susceptibility to sample contamination, loss of trace elemental components, and compatibility with other operations in the overall DNAA procedures. A complete DNAA procedure was proposed and evaluated for the analysis of standard bovine liver and blood samples. The DNAA system was effective for the determination of As, Cu, Fe, Hg, Mo, Rb, Sb, Se, and Zn without yield determinations and with a minimum turn-around time of approximately 3 days.

Application of synchrotron radiation to x-ray fluorescence analysis of trace elements

International Nuclear Information System (INIS)

Gordon, B.M.; Jones, K.W.; Hanson, A.L.

1986-08-01

The development of synchrotron radiation x-ray sources has provided the means to greatly extend the capabilities of x-ray fluorescence analysis for determinations of trace element concentrations. A brief description of synchrotron radiation properties provides a background for a discussion of the improved detection limits compared to existing x-ray fluorescence techniques. Calculated detection limits for x-ray microprobes with micrometer spatial resolutions are described and compared with experimental results beginning to appear from a number of laboratories. The current activities and future plans for a dedicated x-ray microprobe beam line at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory are presented

LASL lens design procedure: simple, fast, precise, versatile

International Nuclear Information System (INIS)

Brixner, B.

1978-11-01

The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations

Evaluation of simulation alternatives for the brute-force ray-tracing approach used in backlight design

Science.gov (United States)

Desnijder, Karel; Hanselaer, Peter; Meuret, Youri

2016-04-01

A key requirement to obtain a uniform luminance for a side-lit LED backlight is the optimised spatial pattern of structures on the light guide that extract the light. The generation of such a scatter pattern is usually performed by applying an iterative approach. In each iteration, the luminance distribution of the backlight with a particular scatter pattern is analysed. This is typically performed with a brute-force ray-tracing algorithm, although this approach results in a time-consuming optimisation process. In this study, the Adding-Doubling method is explored as an alternative way for evaluating the luminance of a backlight. Due to the similarities between light propagating in a backlight with extraction structures and light scattering in a cloud of light scatterers, the Adding-Doubling method which is used to model the latter could also be used to model the light distribution in a backlight. The backlight problem is translated to a form upon which the Adding-Doubling method is directly applicable. The calculated luminance for a simple uniform extraction pattern with the Adding-Doubling method matches the luminance generated by a commercial raytracer very well. Although successful, no clear computational advantage over ray tracers is realised. However, the dynamics of light propagation in a light guide as used the Adding-Doubling method, also allow to enhance the efficiency of brute-force ray-tracing algorithms. The performance of this enhanced ray-tracing approach for the simulation of backlights is also evaluated against a typical brute-force ray-tracing approach.

Investigation of propagation algorithms for ray-tracing simulation of polarized neutrons

DEFF Research Database (Denmark)

Bergbäck Knudsen, Erik; Tranum-Rømer, A.; Willendrup, Peter Kjær

2014-01-01

Ray-tracing of polarized neutrons faces a challenge when the neutron propagates through an inhomogeneous magnetic field. This affects simulations of novel instruments using encoding of energy or angle into the neutron spin. We here present a new implementation of propagation of polarized neutrons...

Ray tracing the Wigner distribution function for optical simulations

Science.gov (United States)

Mout, Marco; Wick, Michael; Bociort, Florian; Petschulat, Joerg; Urbach, Paul

2018-01-01

We study a simulation method that uses the Wigner distribution function to incorporate wave optical effects in an established framework based on geometrical optics, i.e., a ray tracing engine. We use the method to calculate point spread functions and show that it is accurate for paraxial systems but produces unphysical results in the presence of aberrations. The cause of these anomalies is explained using an analytical model.

Total reflection X-ray fluorescence as a convenient tool for determination of trace elements in microscale gasoline and diesel

Science.gov (United States)

Zhang, Airui; Jin, Axiang; Wang, Hai; Wang, Xiaokang; Zha, Pengfei; Wang, Meiling; Song, Xiaoping; Gao, Sitian

2018-03-01

Quantitative determination of trace elements like S, Fe, Cu, Mn and Pb in gasoline and S in diesel is of great importance due to the growing concerns over air pollution, human health and engine failure caused by utilization of gasoline and diesel with these harmful elements. A method of total reflection X-ray fluorescence (TXRF) was developed to measure these harmful trace elements in gasoline and diesel. A variety of factors to affect measurement results, including TXRF parameters, microwave-assisted digestion conditions and internal standard element and its addition, were examined to optimize these experimental procedures. The hydrophobic treatment of the surface of quartz reflectors to support the analyte with neutral silicone solutions could prepare thin films of gasoline and diesel digestion solutions for subsequent TXRF analysis. The proposed method shows good potential and reliability to determine the content of harmful trace elements in gasoline and diesel with high sensitivity and accuracy without drawing different standard calibration curves, and can be easily employed to screen gasoline and diesel in routine quality control and assurance.

The elimination of ray tracing in Monte Carlo shielding programs

International Nuclear Information System (INIS)

Bendall, D.E.

1988-01-01

The MONK6 code has clearly demonstrated the advantages of hole tracking, which was devised by Woodcock et at. for use in criticality codes from earlier work by Von Neumann. Hole tracking eliminates ray tracing by introducing, for all materials present in the problem, a pseudo scattering reaction that forward scatters without energy loss. The cross section for this reaction is chosen so that the total cross sections for all the materials are equal at a given energy. By this means, tracking takes place with a constant total cross section everywhere, so there is now no need to ray trace. The present work extends hole tracking to shielding codes, where it functions in tandem with Russian roulette and splitting. An algorithm has been evolved and its performance is compared with the ray-tracking code McBEND. A disadvantage with hole tracking occurs when there is a wide variation in total cross section for materials present. As the tracking uses the total cross section of the material that has the maximum cross section, there can be a large number of pseudo collisions in the materials with low total cross sections. In extreme cases, the advantages of hole tracking can be lost by the by the extra time taken in servicing these pseudo collisions; however, techniques for eliminating this problem are under consideration

High performance dosimetry calculations using adapted ray-tracing

International Nuclear Information System (INIS)

Perrotte, Lancelot; Saupin, Guillaume

2010-01-01

When preparing interventions on nuclear sites, it is interesting to study different scenarios, to identify the most appropriate one for the operator(s). Using virtual reality tools is a good way to simulate the potential scenarios. Thus, taking advantage of very efficient computation times can help the user studying different complex scenarios, by immediately evaluating the impact of any changes. In the field of radiation protection, people often use computation codes based on the straight line attenuation method with build-up factors. As for other approaches, geometrical computations (finding all the interactions between radiation rays and the scene objects) remain the bottleneck of the simulation. We present in this paper several optimizations used to speed up these geometrical computations, using innovative GPU ray-tracing algorithms. For instance, we manage to compute every intersection between 600 000 rays and a huge 3D industrial scene in a fraction of second. Moreover, our algorithm works the same way for both static and dynamic scenes, allowing easier study of complex intervention scenarios (where everything moves: the operator(s), the shielding objects, the radiation sources).

A Sub-band Divided Ray Tracing Algorithm Using the DPS Subspace in UWB Indoor Scenarios

DEFF Research Database (Denmark)

Gan, Mingming; Xu, Zhinan; Hofer, Markus

2015-01-01

Sub-band divided ray tracing (SDRT) is one technique that has been extensively used to obtain the channel characteristics for ultra-wideband (UWB) radio wave propagation in realistic indoor environments. However, the computational complexity of SDRT scales directly with the number of sub-bands. A......Sub-band divided ray tracing (SDRT) is one technique that has been extensively used to obtain the channel characteristics for ultra-wideband (UWB) radio wave propagation in realistic indoor environments. However, the computational complexity of SDRT scales directly with the number of sub...

Numerical simulation and comparison of nonlinear self-focusing based on iteration and ray tracing

Science.gov (United States)

Li, Xiaotong; Chen, Hao; Wang, Weiwei; Ruan, Wangchao; Zhang, Luwei; Cen, Zhaofeng

2017-05-01

Self-focusing is observed in nonlinear materials owing to the interaction between laser and matter when laser beam propagates. Some of numerical simulation strategies such as the beam propagation method (BPM) based on nonlinear Schrödinger equation and ray tracing method based on Fermat's principle have applied to simulate the self-focusing process. In this paper we present an iteration nonlinear ray tracing method in that the nonlinear material is also cut into massive slices just like the existing approaches, but instead of paraxial approximation and split-step Fourier transform, a large quantity of sampled real rays are traced step by step through the system with changing refractive index and laser intensity by iteration. In this process a smooth treatment is employed to generate a laser density distribution at each slice to decrease the error caused by the under-sampling. The characteristics of this method is that the nonlinear refractive indices of the points on current slice are calculated by iteration so as to solve the problem of unknown parameters in the material caused by the causal relationship between laser intensity and nonlinear refractive index. Compared with the beam propagation method, this algorithm is more suitable for engineering application with lower time complexity, and has the calculation capacity for numerical simulation of self-focusing process in the systems including both of linear and nonlinear optical media. If the sampled rays are traced with their complex amplitudes and light paths or phases, it will be possible to simulate the superposition effects of different beam. At the end of the paper, the advantages and disadvantages of this algorithm are discussed.

A new hybrid algorithm using thermodynamic and backward ray-tracing approaches for modeling luminescent solar concentrators

Energy Technology Data Exchange (ETDEWEB)

Lo, Ch. K.; Lim, Y. S.; Tan, S. G.; Rahman, F. A. [Faculty of Engineering and Science, University Tunku Abdul Rahman, Jalan Genting Klang, 53300, Kuala Lumpur (Malaysia)

2010-12-15

A Luminescent Solar Concentrator (LSC) is a transparent plate containing luminescent material with photovoltaic (PV) cells attached to its edges. Sunlight entering the plate is absorbed by the luminescent material, which in turn emits light. The emitted light propagates through the plate and arrives at the PV cells through total internal reflection. The ratio of the area of the relatively cheap polymer plate to that of the expensive PV cells is increased, and the cost per unit of solar electricity can be reduced by 75%. To improve the emission performance of LSCs, simulation modeling of LSCs becomes essential. Ray-tracing modeling is a popular approach for simulating LSCs due to its great ability of modeling various LSC structures under direct and diffuse sunlight. However, this approach requires substantial amount of measurement input data. Also, the simulation time is enormous because it is a forward-ray tracing method that traces all the rays propagating from the light source to the concentrator. On the other hand, the thermodynamic approach requires substantially less input parameters and simulation time, but it can only be used to model simple LSC designs with direct sunlight. Therefore, a new hybrid model was developed to perform various simulation studies effectively without facing the issues arisen from the existing ray-tracing and thermodynamic models. The simulation results show that at least 60% of the total output irradiance of a LSC is contributed by the light trapped and channeled by the LSC. The novelty of this hybrid model is the concept of integrating the thermodynamic model with a well-developed Radiance ray-tracing model, hence making this model as a fast, powerful and cost-effective tool for the design of LSCs. (authors)

3D Laser Imprint Using a Smoother Ray-Traced Power Deposition Method

Science.gov (United States)

Schmitt, Andrew J.

2017-10-01

Imprinting of laser nonuniformities in directly-driven icf targets is a challenging problem to accurately simulate with large radiation-hydro codes. One of the most challenging aspects is the proper construction of the complex and rapidly changing laser interference structure driving the imprint using the reduced laser propagation models (usually ray-tracing) found in these codes. We have upgraded the modelling capability in our massively-parallel fastrad3d code by adding a more realistic EM-wave interference structure. This interference model adds an axial laser speckle to the previous transverse-only laser structure, and can be impressed on our improved smoothed 3D raytrace package. This latter package, which connects rays to form bundles and performs power deposition calculations on the bundles, is intended to decrease ray-trace noise (which can mask or add to imprint) while using fewer rays. We apply this improved model to 3D simulations of recent imprint experiments performed on the Omega-EP laser and the Nike laser that examined the reduction of imprinting due to very thin high-Z target coatings. We report on the conditions in which this new model makes a significant impact on the development of laser imprint. Supported by US DoE/NNSA.

Diagnostic x-ray procedures and risk of leukemia, lymphoma, and multiple myeloma

International Nuclear Information System (INIS)

Boice, J.D. Jr.; Morin, M.M.; Glass, A.G.; Friedman, G.D.; Stovall, M.; Hoover, R.N.; Fraumeni, J.F. Jr.

1991-01-01

Exposure to diagnostic x-rays and the risk of leukemia, non-Hodgkin's lymphoma (NHL), and multiple myeloma were studied within two prepaid health plans. Adult patients with leukemia (n = 565), NHL (n = 318), and multiple myeloma (n = 208) were matched to controls (n = 1390), and over 25,000 x-ray procedures were abstracted from medical records. Dose response was evaluated by assigning each x-ray procedure a score based on estimated bone marrow dose. X-ray exposure was not associated with chronic lymphocytic leukemia, one of the few malignant conditions never linked to radiation (relative risk [RR], 0.66). For all other forms of leukemia combined (n = 358), there was a slight elevation in risk (RR, 1.17) but no evidence of a dose-response relationship when x-ray procedures near the time of diagnosis were excluded. Similarly, patients with NHL were exposed to diagnostic x-ray procedures more often than controls (RR, 1.32), but the RR fell to 0.99 when the exposure to diagnostic x-ray procedures within 2 years of diagnosis was ignored. For multiple myeloma, overall risk was not significantly high (RR, 1.14), but there was consistent evidence of increasing risk with increasing numbers of diagnostic x-ray procedures. These data suggest that persons with leukemia and NHL undergo x-ray procedures frequently just prior to diagnosis for conditions related to the development or natural history of their disease. There was little evidence that diagnostic x-ray procedures were causally associated with leukemia or NHL. The risk for multiple myeloma, however, was increased among those patients who were frequently exposed to x-rays

R-LODs: fast LOD-based ray tracing of massive models

Energy Technology Data Exchange (ETDEWEB)

Yoon, Sung-Eui; Lauterbach, Christian; Manocha, Dinesh

2006-08-25

We present a novel LOD (level-of-detail) algorithm to accelerate ray tracing of massive models. Our approach computes drastic simplifications of the model and the LODs are well integrated with the kd-tree data structure. We introduce a simple and efficient LOD metric to bound the error for primary and secondary rays. The LOD representation has small runtime overhead and our algorithm can be combined with ray coherence techniques and cache-coherent layouts to improve the performance. In practice, the use of LODs can alleviate aliasing artifacts and improve memory coherence. We implement our algorithm on both 32bit and 64bit machines and able to achieve up to 2.20 times improvement in frame rate of rendering models consisting of tens or hundreds of millions of triangles with little loss in image quality.

Particle induced X-ray emission for quantitative trace-element analysis using the Eindhoven cyclotron

International Nuclear Information System (INIS)

Kivits, H.

1980-01-01

Development of a multi-elemental trace analysis technique using PIXE (Particle Induced X-ray Emission), was started almost five years ago at the Eindhoven University of Technology, in the Cyclotron Applications Group of the Physics Department. The aim of the work presented is to improve the quantitative aspects of trace-element analysis with PIXE, as well as versatility, speed and simplicity. (Auth.)

Combined visualization for noise mapping of industrial facilities based on ray-tracing and thin plate splines

Science.gov (United States)

Ovsiannikov, Mikhail; Ovsiannikov, Sergei

2017-01-01

The paper presents the combined approach to noise mapping and visualizing of industrial facilities sound pollution using forward ray tracing method and thin-plate spline interpolation. It is suggested to cauterize industrial area in separate zones with similar sound levels. Equivalent local source is defined for range computation of sanitary zones based on ray tracing algorithm. Computation of sound pressure levels within clustered zones are based on two-dimension spline interpolation of measured data on perimeter and inside the zone.

Instrumental trace element analysis of California market milk

International Nuclear Information System (INIS)

Ragaini, R.C.; Langhorst, A.L.; Ralston, H.R.; Heft, R.

1975-01-01

Trace element analysis for 15 elements (Zn, Na, Br, Rb, Sr, Mg, Al, Ca, Cl, I, K, Fe, Co, Se, Cs) was carried out on 32 samples of California market milk and 6 samples of Colorado milk in a pilot study of toxic and nutrient trace elements in the soil-forage-cow-milk food chain. The techniques of instrumental neutron activation analysis and x-ray fluorescence analysis are described. Sample collection, preparation, analysis, and data reduction procedures are discussed. The mean values and variations of trace element concentrations in milk are compared to data from other studies. (U.S.)

Optimization of Monte Carlo algorithms and ray tracing on GPUs

International Nuclear Information System (INIS)

Bergmann, R.M.; Vujic, J.L.

2013-01-01

To take advantage of the computational power of GPUs (Graphical Processing Units), algorithms that work well on CPUs must be modified to conform to the GPU execution model. In this study, typical task-parallel Monte Carlo algorithms have been reformulated in a data-parallel way, and the benefits of doing so are examined. We were able to show that the data-parallel approach greatly improves thread coherency and keeps thread blocks busy, improving GPU utilization compared to the task-parallel approach. Data-parallel does not, however, outperform the task-parallel approach in regards to speedup over CPU. Regarding the ray-tracing acceleration, OptiX shows promise for providing enough ray tracing speed to be used in a full 3D Monte Carlo neutron transport code for reactor calculations. It is important to note that it is necessary to operate on large datasets of particle histories in order to have good performance in both OptiX and the data-parallel algorithm since this reduces the impact of latency. Our paper also shows the need to rewrite standard Monte Carlo algorithms in order to take full advantage of these new, powerful processor architectures

A new 3-D ray tracing method based on LTI using successive partitioning of cell interfaces and traveltime gradients

Science.gov (United States)

Zhang, Dong; Zhang, Ting-Ting; Zhang, Xiao-Lei; Yang, Yan; Hu, Ying; Qin, Qian-Qing

2013-05-01

We present a new method of three-dimensional (3-D) seismic ray tracing, based on an improvement to the linear traveltime interpolation (LTI) ray tracing algorithm. This new technique involves two separate steps. The first involves a forward calculation based on the LTI method and the dynamic successive partitioning scheme, which is applied to calculate traveltimes on cell boundaries and assumes a wavefront that expands from the source to all grid nodes in the computational domain. We locate several dynamic successive partition points on a cell's surface, the traveltimes of which can be calculated by linear interpolation between the vertices of the cell's boundary. The second is a backward step that uses Fermat's principle and the fact that the ray path is always perpendicular to the wavefront and follows the negative traveltime gradient. In this process, the first-arriving ray path can be traced from the receiver to the source along the negative traveltime gradient, which can be calculated by reconstructing the continuous traveltime field with cubic B-spline interpolation. This new 3-D ray tracing method is compared with the LTI method and the shortest path method (SPM) through a number of numerical experiments. These comparisons show obvious improvements to computed traveltimes and ray paths, both in precision and computational efficiency.

Ray Tracing modelling of reflector for vertical bifacial panel

DEFF Research Database (Denmark)

Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

2016-01-01

Bifacial solar panels have recently become a new attractive building block for PV systems. In this work we propose a reflector system for a vertical bifacial panel, and use ray tracing modelling to model the performance. Particularly, we investigate the impact of the reflector volume being filled...... with a refractive medium, and shows the refractive medium improves the reflector performance since it directs almost all the light incident on the incoming plane into the PV panel....

X-ray trace element analysis with positive ion beams

International Nuclear Information System (INIS)

Davis, R.H.

1973-01-01

A new trace element analysis having the advantage that many elements may be detected in a single measurement, based on positive charged particle induced X-ray florescence and on the production of X-rays by heavy ions, is described. Because of the large cross-sections for the production of discrete X-ray and the low yield of continuum radiation, positive charged particle X-ray florescence is a competitive, fast, analytic tool. In the experiment a beam of positive charged particles from an accelerator was directed toward a target. X-rays induced by the bombardment were detected by a Si(Li) detector the ouput from which was amplified and sorted in a multichannel analyzer. For rapid data handling and analysis, the multichannel analyzer or ADC unit was connected to an on-line computer. A large variety of targets prepared in collaboration with the oceanographers have been studied and spectra obtained for different particles having the same velocity are presented to show that the yield of discrete X-rays increases at least as rapidly as Z 2 . While protons of several MeV appear to be already competitive further advantage may be gained by heavy ions at lower energies since the continuum is reduced while the peak ''signals'' retain strength due to the Z 2 dependence. (S.B.)

X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Ray, N.B.

1977-01-01

The principle, instrument and procedure of X-ray fluorescence spectrometry are described. It is a rapid, simple and sensitive method for the trace analysis of elements from sodium to uranium in powder, liquid or metal samples. (M.G.B.)

The quantitative determination of trace elements in giant unicellular plants by particle-induced X-ray emission

International Nuclear Information System (INIS)

Navarrete-Dominguez, V.R.; Yoshihara, K.; Tanaka, N.

1982-01-01

Particle-induced X-ray emission (PIXE) was applied for the determination of trace elements in biologically interesting materials, giant unicellular plants. It was found that the PIXE method had advantages in multi-element trace analysis of a single cell of the sample plant. (author)

(U) Second-Order Sensitivity Analysis of Uncollided Particle Contributions to Radiation Detector Responses Using Ray-Tracing

Energy Technology Data Exchange (ETDEWEB)

Favorite, Jeffrey A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-30

The Second-Level Adjoint Sensitivity System (2nd-LASS) that yields the second-order sensitivities of a response of uncollided particles with respect to isotope densities, cross sections, and source emission rates is derived in Refs. 1 and 2. In Ref. 2, we solved problems for the uncollided leakage from a homogeneous sphere and a multiregion cylinder using the PARTISN multigroup discrete-ordinates code. In this memo, we derive solutions of the 2nd-LASS for the particular case when the response is a flux or partial current density computed at a single point on the boundary, and the inner products are computed using ray-tracing. Both the PARTISN approach and the ray-tracing approach are implemented in a computer code, SENSPG. The next section of this report presents the equations of the 1st- and 2nd-LASS for uncollided particles and the first- and second-order sensitivities that use the solutions of the 1st- and 2nd-LASS. Section III presents solutions of the 1st- and 2nd-LASS equations for the case of ray-tracing from a detector point. Section IV presents specific solutions of the 2nd-LASS and derives the ray-trace form of the inner products needed for second-order sensitivities. Numerical results for the total leakage from a homogeneous sphere are presented in Sec. V and for the leakage from one side of a two-region slab in Sec. VI. Section VII is a summary and conclusions.

Accounting for partiality in serial crystallography using ray-tracing principles

International Nuclear Information System (INIS)

Kroon-Batenburg, Loes M. J.; Schreurs, Antoine M. M.; Ravelli, Raimond B. G.; Gros, Piet

2015-01-01

Serial crystallography generates partial reflections from still diffraction images. Partialities are estimated with EVAL ray-tracing simulations, thereby improving merged reflection data to a similar quality as conventional rotation data. Serial crystallography generates ‘still’ diffraction data sets that are composed of single diffraction images obtained from a large number of crystals arbitrarily oriented in the X-ray beam. Estimation of the reflection partialities, which accounts for the expected observed fractions of diffraction intensities, has so far been problematic. In this paper, a method is derived for modelling the partialities by making use of the ray-tracing diffraction-integration method EVAL. The method estimates partialities based on crystal mosaicity, beam divergence, wavelength dispersion, crystal size and the interference function, accounting for crystallite size. It is shown that modelling of each reflection by a distribution of interference-function weighted rays yields a ‘still’ Lorentz factor. Still data are compared with a conventional rotation data set collected from a single lysozyme crystal. Overall, the presented still integration method improves the data quality markedly. The R factor of the still data compared with the rotation data decreases from 26% using a Monte Carlo approach to 12% after applying the Lorentz correction, to 5.3% when estimating partialities by EVAL and finally to 4.7% after post-refinement. The merging R int factor of the still data improves from 105 to 56% but remains high. This suggests that the accuracy of the model parameters could be further improved. However, with a multiplicity of around 40 and an R int of ∼50% the merged still data approximate the quality of the rotation data. The presented integration method suitably accounts for the partiality of the observed intensities in still diffraction data, which is a critical step to improve data quality in serial crystallography

Accounting for partiality in serial crystallography using ray-tracing principles

Energy Technology Data Exchange (ETDEWEB)

Kroon-Batenburg, Loes M. J., E-mail: l.m.j.kroon-batenburg@uu.nl; Schreurs, Antoine M. M. [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Ravelli, Raimond B. G. [Maastricht University, PO Box 616, 6200 MD Maastricht (Netherlands); Gros, Piet [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands)

2015-08-25

Serial crystallography generates partial reflections from still diffraction images. Partialities are estimated with EVAL ray-tracing simulations, thereby improving merged reflection data to a similar quality as conventional rotation data. Serial crystallography generates ‘still’ diffraction data sets that are composed of single diffraction images obtained from a large number of crystals arbitrarily oriented in the X-ray beam. Estimation of the reflection partialities, which accounts for the expected observed fractions of diffraction intensities, has so far been problematic. In this paper, a method is derived for modelling the partialities by making use of the ray-tracing diffraction-integration method EVAL. The method estimates partialities based on crystal mosaicity, beam divergence, wavelength dispersion, crystal size and the interference function, accounting for crystallite size. It is shown that modelling of each reflection by a distribution of interference-function weighted rays yields a ‘still’ Lorentz factor. Still data are compared with a conventional rotation data set collected from a single lysozyme crystal. Overall, the presented still integration method improves the data quality markedly. The R factor of the still data compared with the rotation data decreases from 26% using a Monte Carlo approach to 12% after applying the Lorentz correction, to 5.3% when estimating partialities by EVAL and finally to 4.7% after post-refinement. The merging R{sub int} factor of the still data improves from 105 to 56% but remains high. This suggests that the accuracy of the model parameters could be further improved. However, with a multiplicity of around 40 and an R{sub int} of ∼50% the merged still data approximate the quality of the rotation data. The presented integration method suitably accounts for the partiality of the observed intensities in still diffraction data, which is a critical step to improve data quality in serial crystallography.

Theoretical estimation of proton induced X-ray emission yield of the trace elements present in the lung and breast cancer

International Nuclear Information System (INIS)

Manjunatha, H.C.; Sowmya, N.

2013-01-01

X-rays may be produced following the excitation of target atoms induced by an energetic incident ion beam of protons. Proton induced X-ray emission (PIXE) analysis has been used for many years for the determination of elemental composition of materials using X-rays. Recent interest in the proton induced X-ray emission cross section has arisen due to their importance in the rapidly expanding field of PIXE analysis. One of the steps in the analysis is to fit the measured X-ray spectrum with theoretical spectrum. The theoretical cross section and yields are essential for the evaluation of spectrum. We have theoretically evaluated the PIXE cross sections for trace elements in the lung and breast cancer tissues such as Cl, K, Ca,Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, P, S, Sr, Hg and Pb. The estimated cross section is used in the evaluation of Proton induced X-ray emission spectrum for the given trace elements.We have also evaluated the Proton induced X-ray emission yields in the thin and thick target of the given trace elements. The evaluated Proton induced X-ray emission cross-section, spectrum and yields are graphically represented. Some of these values are also tabulated. Proton induced X-ray emission cross sections and a yield for the given trace elements varies with the energy. PIXE yield depends on a real density and does not on thickness of the target. (author)

Quantification and localization of trace metals in natural plankton using a synchrotron x-ray fluorescence microprobe

International Nuclear Information System (INIS)

Twining, B. S.; Baines, S. B.; Fisher, N. S.; Jacobsen, C.; Maser, J.; State Univ. of New York at Stony Brook

2003-01-01

The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 (micro)m. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Cl-related background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence

Quantification and localization of trace metals in natural plancton using a synchrotron x-ray fluorescence microprobe.

Energy Technology Data Exchange (ETDEWEB)

Twining, B. S.; Baines, S. B.; Fisher, N. S.; Jacobsen, C.; Maser, J.; State Univ. of New York at Stony Brook

2003-03-01

The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 {micro}m. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Cl-related background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence.

Development of a procedure for the multi-element determination of trace elements in wine by ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Castineira, M.M.; Brandt, R.; von Bohlen, A.; Jakubowski, N. [Institut fuer Spektrochemie und Angewandte Spektroskopie e.V., Dortmund (Germany)

2001-07-01

An inductively coupled plasma mass spectrometric (ICP-MS) procedure has been developed for the determination of trace elements in wine. The procedure consists in simple 1+1 dilution of the wine and semi-quantitative analysis (without external calibration) using In as internal standard. Thirty-one elements at concentrations ranging from 0.1 mg mL{sup -1} to 0.5 ng mL{sup -1} can be determined by ICP-MS analysis with and without digestion. It was investigated whether a matrix effect observed for EtOH in the wine matrix can be overcome by application of a micro-concentric nebulizer with a membrane desolvator (MCN 6000). The results obtained for the MCN 6000 are compared with those obtained by use of a conventional Meinhard nebulizer. It is shown that the observed matrix effect can only be compensated by use of an internal standard for the Meinhard nebulizer, but not for the MCN 6000. Results for ICP-MS are compared with those obtained by total reflection X-ray fluorescence spectrometry (TXRF). (orig.)

Comparison of matrix method and ray tracing in the study of complex optical systems

Science.gov (United States)

Anterrieu, Eric; Perez, Jose-Philippe

2000-06-01

In the context of the classical study of optical systems within the geometrical Gauss approximation, the cardinal elements are efficiently obtained with the aid of the transfer matrix between the input and output planes of the system. In order to take into account the geometrical aberrations, a ray tracing approach, using the Snell- Descartes laws, has been implemented in an interactive software. Both methods are applied for measuring the correction to be done to a human eye suffering from ametropia. This software may be used by optometrists and ophthalmologists for solving the problems encountered when considering this pathology. The ray tracing approach gives a significant improvement and could be very helpful for a better understanding of an eventual surgical act.

A general ray-tracing algorithm for the solution of the neutron transport equation by the collision probability method

International Nuclear Information System (INIS)

Ball, G.

1990-01-01

The development and analysis of methods for generating first-flight collision probabilities in two-dimensional geometries consistent with Light Water Moderated (LWR) fuel assemblies are examined. A new ray-tracing algorithm is discussed. A number of numerical results are given demonstrating the feasibility of this algorithm and the effects of the moderator (and fuel) sectorizations on the resulting flux distributions. The collision probabilties have been introduced and their subsequent utilization in the flux calculation procedures illustrated. A brief description of the Coxy-1 and Coxy-2 programs (which were developed in the Reactor Theory Division of the Atomic Energy Agency of South Africa Ltd) has also been added. 41 figs., 9 tabs., 18 refs

Additional radiation dose to population due to X-ray diagnostic procedures

International Nuclear Information System (INIS)

Chougule, A.

2006-01-01

Full text of publication follows: Discovery of X rays has revolutionised the medical diagnosis but the fact that the diagnostic radiological procedures contribute about 80 to 90 % of the radiation dose to population as compared to other man made radiation sources cannot be ignored especially when X ray diagnostic facilities are being made available to larger section of the society. The estimated frequency of radiological procedures in India is 12,000 procedures/ year/100,000 population, though it is quite less as compared to developed countries, its increasing day by day. As part of the project, a radiation protection survey of X ray installations and patient radiation dose measurement during various radiological procedures was undertaken. 193 X ray installations were surveyed and the radiation doses received by the patient during various radiological procedure was measured. For measurement of radiation doses, CaSO 4 : Dy thermoluminescence (T.L.) discs of size 13.3 mm diameter and 0.8 mm thickness were used. Pre annealed T.L. discs were fixed by adhesive tape on the patient skin at the center of entrance beam before the exposure. After exposure the T.L. discs were estimated f or entrance skin dose during that particular projection/ examination. 10,000 measurements at different centers during various radiological procedures were done. It was found that chest radiography accounts for 37 % of all radiological procedures and further it was observed that 70 % of the chest X rays were normal with out any pathology indicating scope for curtailing the unwarranted radiological procedures. The special investigations like barium swallow, barium meal and fallow through accounts for about 1.5 % of the total radiological procedures. The entrance skin dose [E.S.D.] during chest radiography was 0.3 + 0.1 mGy where as during K.U.B. and cervical spine radiography it was 6.2 + 1.1 mGy and 5.1 + 0.9 mGy respectively. The details of frequency of various radiological procedures and the

A comparison of ray-tracing software for the design of quadrupole microbeam systems

International Nuclear Information System (INIS)

Incerti, S.; Smith, R.W.; Merchant, M.; Grime, G.W.; Meot, F.; Serani, L.; Moretto, Ph.; Touzeau, C.; Barberet, Ph.; Habchi, C.; Nguyen, D.T.

2005-01-01

For many years the only ray-tracing software available with sufficient precision for the design of quadrupole microbeam focusing systems has been OXRAY and its successor TRAX, developed at Oxford in the 1980s. With the current interest in pushing the beam diameter into the nanometre region, this software has become dated and more importantly the precision at small displacements may not be sufficient and new simulation tools are required. Two candidates for this are Zgoubi, developed at CEA as a general beam line design tool and the CERN simulation program Geant in its latest version Geant4. In order to use Geant4 new quadrupole field modules have been developed and implemented. In this paper the capabilities of the three codes TRAX, Zgoubi and Geant4 are reviewed. Comparisons of ray-tracing calculations in a high demagnification quadrupole probe-forming system for the sub-micron region are presented

Thermal radiation characteristics of nonisothermal cylindrical enclosures using a numerical ray tracing technique

Science.gov (United States)

Baumeister, Joseph F.

1990-01-01

Analysis of energy emitted from simple or complex cavity designs can lead to intricate solutions due to nonuniform radiosity and irradiation within a cavity. A numerical ray tracing technique was applied to simulate radiation propagating within and from various cavity designs. To obtain the energy balance relationships between isothermal and nonisothermal cavity surfaces and space, the computer code NEVADA was utilized for its statistical technique applied to numerical ray tracing. The analysis method was validated by comparing results with known theoretical and limiting solutions, and the electrical resistance network method. In general, for nonisothermal cavities the performance (apparent emissivity) is a function of cylinder length-to-diameter ratio, surface emissivity, and cylinder surface temperatures. The extent of nonisothermal conditions in a cylindrical cavity significantly affects the overall cavity performance. Results are presented over a wide range of parametric variables for use as a possible design reference.

Novel applications of the x-ray tracing software package McXtrace

DEFF Research Database (Denmark)

Bergbäck Knudsen, Erik; Nielsen, Martin Meedom; Haldrup, Kristoffer

2014-01-01

We will present examples of applying the X-ray tracing software package McXtrace to different kinds of X-ray scattering experiments. In particular we will be focusing on time-resolved type experiments. Simulations of full scale experiments are particularly useful for this kind, especially when...... some of the issues encountered. Generally more than one or all of these effects are present at once. Simulations can in these cases be used to identify distinct footprints of such distortions and thus give the experimenter a means of deconvoluting them from the signal. We will present a study...... of this kind along with the newest developments of the McXtrace software package....

Analytical approximations to the Hotelling trace for digital x-ray detectors

Science.gov (United States)

Clarkson, Eric; Pineda, Angel R.; Barrett, Harrison H.

2001-06-01

The Hotelling trace is the signal-to-noise ratio for the ideal linear observer in a detection task. We provide an analytical approximation for this figure of merit when the signal is known exactly and the background is generated by a stationary random process, and the imaging system is an ideal digital x-ray detector. This approximation is based on assuming that the detector is infinite in extent. We test this approximation for finite-size detectors by comparing it to exact calculations using matrix inversion of the data covariance matrix. After verifying the validity of the approximation under a variety of circumstances, we use it to generate plots of the Hotelling trace as a function of pairs of parameters of the system, the signal and the background.

Ray-tracing 3D dust radiative transfer with DART-Ray: code upgrade and public release

Science.gov (United States)

Natale, Giovanni; Popescu, Cristina C.; Tuffs, Richard J.; Clarke, Adam J.; Debattista, Victor P.; Fischera, Jörg; Pasetto, Stefano; Rushton, Mark; Thirlwall, Jordan J.

2017-11-01

We present an extensively updated version of the purely ray-tracing 3D dust radiation transfer code DART-Ray. The new version includes five major upgrades: 1) a series of optimizations for the ray-angular density and the scattered radiation source function; 2) the implementation of several data and task parallelizations using hybrid MPI+OpenMP schemes; 3) the inclusion of dust self-heating; 4) the ability to produce surface brightness maps for observers within the models in HEALPix format; 5) the possibility to set the expected numerical accuracy already at the start of the calculation. We tested the updated code with benchmark models where the dust self-heating is not negligible. Furthermore, we performed a study of the extent of the source influence volumes, using galaxy models, which are critical in determining the efficiency of the DART-Ray algorithm. The new code is publicly available, documented for both users and developers, and accompanied by several programmes to create input grids for different model geometries and to import the results of N-body and SPH simulations. These programmes can be easily adapted to different input geometries, and for different dust models or stellar emission libraries.

Pseudo forward ray-tracing: A new method for surface validation in cornea topography

NARCIS (Netherlands)

Sicam, V.; Snellenburg, J.J.; van der Heijde, R.G.; van Stokkum, I.H.M.

2007-01-01

PURPOSE. A pseudo forward ray-tracing (PFRT) algorithm is developed to evaluate surface reconstruction in corneal topography. The method can be applied to topographers where one-to-one correspondence between mire and image points can be established. METHODS. The PFRT algorithm was applied on a

Quantitative evaluation of ultrasonic wave propagation in inhomogeneous anisotropic austenitic welds using 3D ray tracing method. Numerical and experimental validation

International Nuclear Information System (INIS)

Kolkoori, Sanjeevareddy

2014-01-01

Austenitic welds and dissimilar welds are extensively used in primary circuit pipes and pressure vessels in nuclear power plants, chemical industries and fossil fuelled power plants because of their high fracture toughness, resistance to corrosion and creep at elevated temperatures. However, cracks may initiate in these weld materials during fabrication process or stress operations in service. Thus, it is very important to evaluate the structural integrity of these materials using highly reliable non-destructive testing (NDT) methods. Ultrasonic non-destructive inspection of austenitic welds and dissimilar weld components is complicated because of anisotropic columnar grain structure leading to beam splitting and beam deflection. Simulation tools play an important role in developing advanced reliable ultrasonic testing (UT) techniques and optimizing experimental parameters for inspection of austenitic welds and dissimilar weld components. The main aim of the thesis is to develop a 3D ray tracing model for quantitative evaluation of ultrasonic wave propagation in an inhomogeneous anisotropic austenitic weld material. Inhomogenity in the anisotropic weld material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The influence of anisotropy on ultrasonic reflection and transmission behaviour in an anisotropic austenitic weld material are quantitatively analyzed in three dimensions. The ultrasonic beam directivity in columnar grained austenitic steel material is determined three dimensionally using Lamb's reciprocity theorem. The developed ray tracing model evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase

Quantitative evaluation of ultrasonic wave propagation in inhomogeneous anisotropic austenitic welds using 3D ray tracing method. Numerical and experimental validation

Energy Technology Data Exchange (ETDEWEB)

Kolkoori, Sanjeevareddy

2014-07-01

Austenitic welds and dissimilar welds are extensively used in primary circuit pipes and pressure vessels in nuclear power plants, chemical industries and fossil fuelled power plants because of their high fracture toughness, resistance to corrosion and creep at elevated temperatures. However, cracks may initiate in these weld materials during fabrication process or stress operations in service. Thus, it is very important to evaluate the structural integrity of these materials using highly reliable non-destructive testing (NDT) methods. Ultrasonic non-destructive inspection of austenitic welds and dissimilar weld components is complicated because of anisotropic columnar grain structure leading to beam splitting and beam deflection. Simulation tools play an important role in developing advanced reliable ultrasonic testing (UT) techniques and optimizing experimental parameters for inspection of austenitic welds and dissimilar weld components. The main aim of the thesis is to develop a 3D ray tracing model for quantitative evaluation of ultrasonic wave propagation in an inhomogeneous anisotropic austenitic weld material. Inhomogenity in the anisotropic weld material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The influence of anisotropy on ultrasonic reflection and transmission behaviour in an anisotropic austenitic weld material are quantitatively analyzed in three dimensions. The ultrasonic beam directivity in columnar grained austenitic steel material is determined three dimensionally using Lamb's reciprocity theorem. The developed ray tracing model evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase

Quantification procedures in micro X-ray fluorescence analysis

International Nuclear Information System (INIS)

Kanngiesser, Birgit

2003-01-01

For the quantification in micro X-ray fluorescence analysis standardfree quantification procedures have become especially important. An introduction to the basic concepts of these quantification procedures is given, followed by a short survey of the procedures which are available now and what kind of experimental situations and analytical problems are addressed. The last point is extended by the description of an own development for the fundamental parameter method, which renders the inclusion of nonparallel beam geometries possible. Finally, open problems for the quantification procedures are discussed

Application of the nudged elastic band method to the point-to-point radio wave ray tracing in IRI modeled ionosphere

Science.gov (United States)

Nosikov, I. A.; Klimenko, M. V.; Bessarab, P. F.; Zhbankov, G. A.

2017-07-01

Point-to-point ray tracing is an important problem in many fields of science. While direct variational methods where some trajectory is transformed to an optimal one are routinely used in calculations of pathways of seismic waves, chemical reactions, diffusion processes, etc., this approach is not widely known in ionospheric point-to-point ray tracing. We apply the Nudged Elastic Band (NEB) method to a radio wave propagation problem. In the NEB method, a chain of points which gives a discrete representation of the radio wave ray is adjusted iteratively to an optimal configuration satisfying the Fermat's principle, while the endpoints of the trajectory are kept fixed according to the boundary conditions. Transverse displacements define the radio ray trajectory, while springs between the points control their distribution along the ray. The method is applied to a study of point-to-point ionospheric ray tracing, where the propagation medium is obtained with the International Reference Ionosphere model taking into account traveling ionospheric disturbances. A 2-dimensional representation of the optical path functional is developed and used to gain insight into the fundamental difference between high and low rays. We conclude that high and low rays are minima and saddle points of the optical path functional, respectively.

Evaluation of various digestion procedures for trace element contents of some food materials

International Nuclear Information System (INIS)

Demirel, Sule; Tuzen, Mustafa; Saracoglu, Sibel; Soylak, Mustafa

2008-01-01

The levels of trace elements in different types of food material consumed in Turkey were determined by flame and graphite furnace atomic absorption spectrometry. Food samples were digested with dry ashing, wet ashing and microwave digestion procedures in this study. The microwave digestion procedure was chosen for the digestion of all the food samples because it required shorter time and made higher recovery (specially for Se). Fe, Cu, Mn, Zn, Al and Se were determined by flame and graphite furnace atomic absorption spectrometry, respectively. Relative standard deviations (RSD) were found below 10%. The accuracy of the procedure was confirmed by certified reference materials. Moreover, this procedure was easier to use when compared with dry and wet digestions

Application of energy dispersive X-ray fluorescence technique for investigations of trace element composition in medicinal plants from Manipur

International Nuclear Information System (INIS)

Joseph, Daisy; Singh, Toudam Sony; Singh, Rajmohan

2009-01-01

Seven medicinal plants from remote areas of Manipur were analyzed for their trace elemental composition using an X-ray spectrometer consisting of a radioisotope source of 109 Cd and Si (Li) X-ray detector of resolution 170 eV at 5.9 keV Mn K-X-ray and its associated electronics. In most samples Ca, Mn, Fe and Sr were predominantly seen and Cu, Zn and Pb were detected at trace levels. The presence and significance of the elements in these medicinal plants will be presented and discussed in the following sections of the paper. (author)

On self-consistent ray-tracing and Fokker-Planck modeling of the hard X-ray emission during lower-hybrid current driven in Tokamaks

International Nuclear Information System (INIS)

Bizarro, J.P.; Peysson, Y.; Bonoli, P.T.; Carrasco, J.; Dudok de Wit, T.; Fuchs, V.; Hoang, G.T.; Litaudon, X.; Moreau, D.; Pocheau, C.; Shkarofsky, I.P.

1993-04-01

A detailed investigation is presented on the ability of combined ray-tracing and Fokker-Planck calculations to predict the hard x-ray (HXR) emission during lower-hybrid (LH) current drive in tokamaks when toroidally induced-ray-stochasticity is important. A large number of rays is used and the electron distribution function is obtained by self-consistently iterating the appropriate LH power deposition and Fokker-Planck calculations. Most of the experimentally observed features of the HXR emission are correctly predicted. It is found that corrections due to radial diffusion of suprathermal electrons and to radiation scattering by the inner wall can be significant

Ray Tracing Study on Top ECCD Launch in KSTAR

Directory of Open Access Journals (Sweden)

Bae Young-soon

2017-01-01

Full Text Available The current drive efficiency of electron cyclotron (EC wave is typically low compared with other RF and neutral beam heating system in tokamak. It is known that EC current drive by outboard launch suffers from low current drive efficiency due to electron trapping. However, the heating and current drive by EC wave is being regarded as a strong candidate for DEMO reactor due to the simplicity of the launcher, none of its interaction with plasma, and no coupling issue at the plasma edge. Also, off-axis heating and current drive by EC wave plays an important role of steady state operation optimization. To enhance the current drive efficiency in DEMO-relevant operation condition having high density and high temperature, the top launch of EC wave is recently proposed in FNSF design [2]. In FNSF, a top launch makes use of a large toroidal component to the launch direction adjusting the vertical launch angle so that the rays propagate nearly parallel to the resonance layer increasing of Doppler shift with higher n||. The results shows a high dimensional efficiency for a broad ECCD profile peaked off axis. In KSTAR, the possibility of efficient off-axis ECCD using top launch is investigated using the ray tracing code, GENRAY [3] for the operating EC frequencies (105 GHz or 140 GHz, and 170 GHz. The high current drive efficiency is found by adjusting the toroidal magnetic field and the radial pivot position of the final launcher mirror for fundamental O-mode and second harmonic X-mode. A large Doppler shift is not quite sure in the typical plasma profile in KSTAR, but the simulation results show high current drive efficiency. This paper presents ray tracing results for many cases with the wave trajectories and damping of EC by scanning the launching angle for specific launcher pivot positions and toroidal magnetic field, and two equilibriums of the KSTAR.

Discrete curved ray-tracing method for radiative transfer in an absorbing-emitting semitransparent slab with variable spatial refractive index

International Nuclear Information System (INIS)

Liu, L.H.

2004-01-01

A discrete curved ray-tracing method is developed to analyze the radiative transfer in one-dimensional absorbing-emitting semitransparent slab with variable spatial refractive index. The curved ray trajectory is locally treated as straight line and the complicated and time-consuming computation of ray trajectory is cut down. A problem of radiative equilibrium with linear variable spatial refractive index is taken as an example to examine the accuracy of the proposed method. The temperature distributions are determined by the proposed method and compared with the data in references, which are obtained by other different methods. The results show that the discrete curved ray-tracing method has a good accuracy in solving the radiative transfer in one-dimensional semitransparent slab with variable spatial refractive index

Line shape and ray trace calculations in saturated X-ray lasers: Application to Ni-like silver

International Nuclear Information System (INIS)

Benredjem, D.; Guilbaud, O.; Moeller, C.; Klisnick, A.; Ros, D.; Dubau, J.; Calisti, A.; Talin, B.

2006-01-01

Longitudinal coherence length in X-ray lasers depends strongly on the shape of the amplified line. We have modelled an experiment performed at the LULI facility of Ecole Polytechnique. The experiment was devoted to the study of the temporal (longitudinal) coherence of the transient Ni-like silver 4d-4p transition X-ray laser at 13.9 nm. Accurate line shape calculations using PPP, a spectral line shape code, confirm that the Voigt profile is a good approximation for this X-ray laser line. This allows us to extensively use the Voigt shape in conditions where the amplifier, i.e. the plasma produced by the interaction of a high intensity laser with a slab target, is neither stationary nor homogeneous. Our calculations involve a ray trace code which is a post-processor to the hydrodynamic simulation EHYBRID. As the effect of saturation is important for the level populations and gains we include the interaction between the amplified beam and the medium using the Maxwell-Bloch formalism. While the FWHM of the spontaneous emission profile is ∼10 mA, the amplified X-ray line exhibits gain narrowing leading to the smaller width ∼3 mA. Comparison with experiment is discussed

Usage of CO2 microbubbles as flow-tracing contrast media in X-ray dynamic imaging of blood flows.

Science.gov (United States)

Lee, Sang Joon; Park, Han Wook; Jung, Sung Yong

2014-09-01

X-ray imaging techniques have been employed to visualize various biofluid flow phenomena in a non-destructive manner. X-ray particle image velocimetry (PIV) was developed to measure velocity fields of blood flows to obtain hemodynamic information. A time-resolved X-ray PIV technique that is capable of measuring the velocity fields of blood flows under real physiological conditions was recently developed. However, technical limitations still remained in the measurement of blood flows with high image contrast and sufficient biocapability. In this study, CO2 microbubbles as flow-tracing contrast media for X-ray PIV measurements of biofluid flows was developed. Human serum albumin and CO2 gas were mechanically agitated to fabricate CO2 microbubbles. The optimal fabricating conditions of CO2 microbubbles were found by comparing the size and amount of microbubbles fabricated under various operating conditions. The average size and quantity of CO2 microbubbles were measured by using a synchrotron X-ray imaging technique with a high spatial resolution. The quantity and size of the fabricated microbubbles decrease with increasing speed and operation time of the mechanical agitation. The feasibility of CO2 microbubbles as a flow-tracing contrast media was checked for a 40% hematocrit blood flow. Particle images of the blood flow were consecutively captured by the time-resolved X-ray PIV system to obtain velocity field information of the flow. The experimental results were compared with a theoretically amassed velocity profile. Results show that the CO2 microbubbles can be used as effective flow-tracing contrast media in X-ray PIV experiments.

X-ray fluorescence analysis for trace element determination in foodstuff chemistry

International Nuclear Information System (INIS)

Wildanger, W.

The physical fundamentals of X-ray fluorescence analysis are given and the routine spectrometers described. The basic principles are given of analytical methods used in qualitative and quantitative fluorescence analyses. Examples are given of the use of the method in a number of fields and the possibility and usefulness is discussed for the determination of trace elements in foodstuffs. The preparation of samples, preliminary concentration of components and calibration methods are discussed. (M.K.)

An Energy Conservative Ray-Tracing Method With a Time Interpolation of the Force Field

Energy Technology Data Exchange (ETDEWEB)

Yao, Jin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-02-10

A new algorithm that constructs a continuous force field interpolated in time is proposed for resolving existing difficulties in numerical methods for ray-tracing. This new method has improved accuracy, but with the same degree of algebraic complexity compared to Kaisers method.

GRay: A MASSIVELY PARALLEL GPU-BASED CODE FOR RAY TRACING IN RELATIVISTIC SPACETIMES

Energy Technology Data Exchange (ETDEWEB)

Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal [Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)

2013-11-01

We introduce GRay, a massively parallel integrator designed to trace the trajectories of billions of photons in a curved spacetime. This graphics-processing-unit (GPU)-based integrator employs the stream processing paradigm, is implemented in CUDA C/C++, and runs on nVidia graphics cards. The peak performance of GRay using single-precision floating-point arithmetic on a single GPU exceeds 300 GFLOP (or 1 ns per photon per time step). For a realistic problem, where the peak performance cannot be reached, GRay is two orders of magnitude faster than existing central-processing-unit-based ray-tracing codes. This performance enhancement allows more effective searches of large parameter spaces when comparing theoretical predictions of images, spectra, and light curves from the vicinities of compact objects to observations. GRay can also perform on-the-fly ray tracing within general relativistic magnetohydrodynamic algorithms that simulate accretion flows around compact objects. Making use of this algorithm, we calculate the properties of the shadows of Kerr black holes and the photon rings that surround them. We also provide accurate fitting formulae of their dependencies on black hole spin and observer inclination, which can be used to interpret upcoming observations of the black holes at the center of the Milky Way, as well as M87, with the Event Horizon Telescope.

Analysis of eight argonne premium coal samples by X-ray fluorescence spectrometry

Science.gov (United States)

Evans, J.R.; Sellers, G.A.; Johnson, R.G.; Vivit, D.V.; Kent, J.

1990-01-01

X-ray fluorescence spectrometric methods were used in the analysis of eight Argonne Premium Coal Samples. Trace elements (Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, and Ce) in coal ash were determined by energy-dispersive X-ray fluorescence spectrometry; major elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, Mn, and Fe) in coal ash and trace elements (Cl and P) in whole coal were determined by wavelength-dispersive X-ray fluorescence spectrometry. The results of this study will be used in a geochemical database compiled for these materials from various analytical techniques. The experimental XRF methods and procedures used to determine these major and trace elements are described.

Trace metal content in aspirin and women's cosmetics via proton induced x-ray emission (PIXE)

International Nuclear Information System (INIS)

Hichwa, B.P.; Pun, D.D.; Wang, D.

1981-01-01

A multielemental analysis to determine the trace metal content of generic and name-brand aspirins and name-brand lipsticks was done via proton induced x-ray (PIXE) measurements. The Hope College PIXE system is described as well as the target preparation methods. The trace metal content of twelve brands of aspirin and aspirin substitutes and fourteen brands of lipstick are reported. Detection limits for most elements are in the range of 100 parts per billion (ppb) to 10 parts per million

Ray Tracing for Dispersive Tsunamis and Source Amplitude Estimation Based on Green's Law: Application to the 2015 Volcanic Tsunami Earthquake Near Torishima, South of Japan

Science.gov (United States)

Sandanbata, Osamu; Watada, Shingo; Satake, Kenji; Fukao, Yoshio; Sugioka, Hiroko; Ito, Aki; Shiobara, Hajime

2018-04-01

Ray tracing, which has been widely used for seismic waves, was also applied to tsunamis to examine the bathymetry effects during propagation, but it was limited to linear shallow-water waves. Green's law, which is based on the conservation of energy flux, has been used to estimate tsunami amplitude on ray paths. In this study, we first propose a new ray tracing method extended to dispersive tsunamis. By using an iterative algorithm to map two-dimensional tsunami velocity fields at different frequencies, ray paths at each frequency can be traced. We then show that Green's law is valid only outside the source region and that extension of Green's law is needed for source amplitude estimation. As an application example, we analyzed tsunami waves generated by an earthquake that occurred at a submarine volcano, Smith Caldera, near Torishima, Japan, in 2015. The ray-tracing results reveal that the ray paths are very dependent on its frequency, particularly at deep oceans. The validity of our frequency-dependent ray tracing is confirmed by the comparison of arrival angles and travel times with those of observed tsunami waveforms at an array of ocean bottom pressure gauges. The tsunami amplitude at the source is nearly twice or more of that just outside the source estimated from the array tsunami data by Green's law.

Fast ray-tracing of human eye optics on Graphics Processing Units.

Science.gov (United States)

Wei, Qi; Patkar, Saket; Pai, Dinesh K

2014-05-01

We present a new technique for simulating retinal image formation by tracing a large number of rays from objects in three dimensions as they pass through the optic apparatus of the eye to objects. Simulating human optics is useful for understanding basic questions of vision science and for studying vision defects and their corrections. Because of the complexity of computing such simulations accurately, most previous efforts used simplified analytical models of the normal eye. This makes them less effective in modeling vision disorders associated with abnormal shapes of the ocular structures which are hard to be precisely represented by analytical surfaces. We have developed a computer simulator that can simulate ocular structures of arbitrary shapes, for instance represented by polygon meshes. Topographic and geometric measurements of the cornea, lens, and retina from keratometer or medical imaging data can be integrated for individualized examination. We utilize parallel processing using modern Graphics Processing Units (GPUs) to efficiently compute retinal images by tracing millions of rays. A stable retinal image can be generated within minutes. We simulated depth-of-field, accommodation, chromatic aberrations, as well as astigmatism and correction. We also show application of the technique in patient specific vision correction by incorporating geometric models of the orbit reconstructed from clinical medical images. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Ray-tracing traveltime tomography versus wave-equation traveltime inversion for near-surface seismic land data

KAUST Repository

Fu, Lei; Hanafy, Sherif M.

2017-01-01

. This initial starting model can be obtained by inverting traveltimes with ray-tracing traveltime tomography (RT) or wave-equation traveltime (WT) inversion. We have found that WT can provide a more accurate tomogram than RT by inverting the first

Correction for interelement effect in X-Ray fluorescence analysis of trace elements in geological materials

International Nuclear Information System (INIS)

El-Behay, A.Z.; Attawiya, M.Y.; Khattab, F.M.

1984-01-01

In a trial to obtain accurate results from X-ray fluorescence technique for the analysis of trace elements in geological materials, two corrections were used for the obtained data, namely, correction for the observed x-ray intensities for absorption and/or enhancement effects due to the presence of other elements in the system and correction for spectral deconvolution to account for the overlapping lines. Significant improvement in the precision and accuracy was obtained and evaluated

Mapping of trace elements with photon microprobes: x-ray fluorescence with focussed synchrotron radiation

International Nuclear Information System (INIS)

Hanson, A.L.; Jones, K.W.; Gordon, B.M.; Pounds, J.G.; Rivers, M.L.; Schidlovsky, G.

1985-04-01

High energy electron synchrotron storage rings provide copious quantities of polarized photons that make possible the mapping of many trace elements with sensitivities at the parts per billion (ppB) level with spatial resolutions in the micrometer range. The brightness of the x-ray ring of the National Synchrotron Light Source (NSLS), presently being commissioned, will be five orders of magnitude larger than that of the bremsstrahlung spectrum of state-of-the-art rotating anode tubes. We will discuss mapping trace elements with a photon microprobe presently being constructed for use at the NSLS. This microprobe will have micrometer spatial resolution

Use of the modified BCR three-step sequential extraction procedure for the study of trace element dynamics in contaminated soils

International Nuclear Information System (INIS)

Pueyo, M.; Mateu, J.; Rigol, A.; Vidal, M.; Lopez-Sanchez, J.F.; Rauret, G.

2008-01-01

The modified BCR three-step sequential extraction procedure was used to examine the temporal dynamics of trace elements in soils contaminated by an accidental spill from an opencast mine in south-west Spain. Soils were mainly contaminated with pyritic sludge and acidic wastewater, whereas some soils were affected only by acidic wastewater. The distributions obtained for both some major (Ca, Fe and Mn) and trace elements (As, Cd, Cu, Pb and Zn) in the sludge and soil samples taken at different times after the accident, 1-3 months and 21 months, were compared. Sequential extractions were useful in identifying different sources of contamination, and in obtaining additional information on the solubility of secondary minerals formed by pyrite oxidation. Thus, the effectiveness of the BCR procedure has proved to be a useful tool for predicting short- and long-term mobility of trace elements, even in complex environmental scenarios. - The modified BCR three-step sequential extraction procedure has proved a useful prediction tool for short- and long-term mobility of trace elements in contaminated soils

A ray-tracing study of electron cyclotron resonance heating in Tokamak plasmas with a superthermal electron tail

International Nuclear Information System (INIS)

Montes, A.; Dendy, R.O.

1987-09-01

We consider a Tokamak plasma in which the distribution of electron velocities in the direction parallel to the magnetic field has a monotonically decreasing superthermal tail. A fully three-dimensional ray-tracing code, which includes a realistic antenna pattern, toroidal effects, and refaction, is used to calculate the absorption of the extraordinary mode in the nonrelativistic limit away from perpendicular incidence. The ray-tracing approach extends results previously obtained in slab geometry (3-8) to a more realistic configuration; it is also essential in dealing with strong refraction in high-density plasmas. Our analytical model for the tail makes available a wide range of tail shapes and parameters. At low densities small tails (tail fraction [pt

Quality control procedure for a general diagnostic x-ray machine

International Nuclear Information System (INIS)

Md Saion Salikin; Mazlyfarina Mohamad

2001-01-01

Performance tests of a particular medical diagnostic x-ray machine have to be carried out regularly in order to ensure that the machine always complies with the required standard. A performance report which is prepared based on the performance tests on the x-ray machine is used as one of the requirement by the authority for issuance and renewal licence to operate and use of the x-ray machine in a clinic or hospital. The Ministry of Health will only issue a licence to the clinic or hospital to use and operate x-ray machines, if the machines have complied with the standards. The clinic or hospital may get the service to carry out performance tests on a diagnostic x-ray machine from any licence H holder, issued by the authority under Atomic Energy Licensing Act 1984. A comparative study between the standard procedure and other procedures on performance test of a general diagnostic x-ray machine is carried out and presented in brief in this paper. The criteria for compliance or otherwise as required by the Ministry of Health Malaysia is discussed and explained in brief. (Author)

Trace element load in cancer and normal lung tissue

International Nuclear Information System (INIS)

Kubala-Kukus, A.; Braziewicz, J.; Banas, D.; Majewska, U.; Gozdz, S.; Urbaniak, A.

1999-01-01

Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described

The flux distribution from a 1.25m2 target aligned heliostat: comparison of ray tracing and experimental results

CSIR Research Space (South Africa)

Maliage, M

2012-05-01

Full Text Available The purpose of this paper is to validate SolTrace for concentrating solar investigations at CSIR by means of a test case: the comparison of the flux distribution in the focal spot of a 1.25 m2 target aligned heliostat predicted by the ray tracing...

Ray tracing for inhomogeneous media applied to the human eye

Science.gov (United States)

Diaz-Gonzalez, G.; Iturbe-Castillo, M. D.; Juarez-Salazar, R.

2017-08-01

Inhomogeneous or gradient index media exhibit a refractive index varying with the position. This kind of media are very interesting because they can be found in both synthetic as well as real life optical devices such as the human lens. In this work we present the development of a computational tool for ray tracing in refractive optical systems. Particularly, the human eye is used as the optical system under study. An inhomogeneous medium with similar characteristics to the human lens is introduced and modeled by the so-called slices method. The useful of our proposal is illustrated by several graphical results.

Proton induced X-ray emission analysis of trace elements in human blood serum

International Nuclear Information System (INIS)

Cheek, D.B.; Hay, H.J.; Newton, C.S.

1979-01-01

Proton induced x-ray emission has been used for quantitative analyses of trace elements in blood serum samples. This work is part of a survey concerned with Zn, Cu, Fe, Cr, Mn and Se in Australian Aboriginal people not receiving optimal diet. Special attention is being directed to Cr because of the high incidence of diabetes mellitus in these people

Quantification of trace elements in protein bands by synchrotron radiation x-ray fluorescence after isoelectric focusing separation of human hemoglobin

International Nuclear Information System (INIS)

Gao Yuxi; Chen Chunying; Li Bai; He Wei; Huang Yuying; Chai Zhifang

2005-01-01

The role and effects of a trace element in a particular organism strongly depend on its particular chemical forms in which the element is present. Therefore, the bulk content or concentration of an element in the organism of interest is often meaningless in judging its biological significance. To understand bioavailability, transportation, cell uptake, metabolism, toxicity, and other biological behaviors of trace elements in the body, information is needed about speciation of trace element, especially about distribution of metal-containing proteins. Development of appropriate methods for speciation analysis is therefore required. Synchrotron radiation x-ray fluorescence (SRXRF) is a sensitive method for multielemental analysis with detection limit of 10 ng/g. It has been successfully used for imaging and quantifying trace elements in various pathological and healthy tissues, even in a single cell, to help understand the mechanism of diseases and the biochemistry of elements. In our previous work, the technique was combined with electrophoresis to study distribution of metalloproteins in biological samples, but the quantitative analysis of trace elements in protein bands after electrophoresis was still unrealized. In this study, a procedure has been proposed for quantification of Fe, Cu, and Zn in protein bands with SRXRF analysis after isoelectric focusing (IEF) separation. Calibration standards were prepared by adding certain amounts of metal ions and free-metal proteins to electrophoresis gel. Human hemoglobin was separated with IEF, and Fe, Cu, and Zn in protein bands were analyzed by SRXRF. The calibration curves can be obtained in a range of 0-8 mg/kg metals and a linear relationship between dosage of metals and fluorescent intensity can be observed (r 2 > 0.99). The method provides the detection limits of 2.43, 1.12, and 0.96 mg/kg for Fe, Cu and Zn, and the recoveries of 90.4 and 115.7 % for Fe and Zn, respectively. The hyphenated technique of SRXRF and IEF

Three-dimensional ray tracing of electrostatic cyclotron harmonic waves and Z mode electromagnetic waves in the magnetosphere

International Nuclear Information System (INIS)

Hashimoto, K.; Yamaashi, K.; Kimura, I.; Kyoto Univ., Japan)

1987-01-01

Three-dimensional ray tracing is performed for electrostatic electron cyclotron harmonic waves and Z mode electromagnetic waves in the earth's magnetosphere using the hot dispersion relation. Propagation characteristics of cyclotron harmonic waves under the electrostatic approximation are considered, and it is noted that waves starting near the equator can propagate over a long distance without damping. Ray tracing without the electrostatic approximation confirms mode conversion from cyclotron harmonic waves to Z mode electromagnetic waves, and the conditions for the conversion are clarified. It is suggested that further conversion to the L-O mode continuum radiation is possible under strict constraints. The present results are not inconsistent with the conversion mechanism for the generation of escaping continuum radiation in the magnetosphere. 20 references

Method to determine trace elements in water samples by neutron activation analysis

International Nuclear Information System (INIS)

Kueppers, G.; Erdtmann, G.

1981-05-01

For the determination of trace elements in water by neutron activation analysis irradiation porcedures and chemical separation procedures have been developed. Irradiation in melted quarz glass ampoules in the presence of a platinum wire (for recombination of the oxyhydrogen gas produced by radiolysis) proved successfull with different variants of the irradiation methods, as long irradiation periods without pressure build-up could be achieved. Possible falsifications of the analysis results were investigated in detail (losses by absorption on vessel walls etc.). The irradiated samples can be measured directly with a gamma ray spectrometer and from the radionuclides found the trace element contents may be calculated. More sensitive determinations are possible if the radionuclides are chemically separated. Procedures for removing the matrix activities, for the separation of the radionuclides in groups of elements and for the isolation of single elements have been developed. For especially sensitive determination of some elements selective separation procedures for antimony, cadmium, selenium, mercury and uranium have been developed. The analytical procedures described have been applied to trace element determinations in river water, glacier ice and water solutions from technical processes. (orig./RB) [de

A versatile ray-tracing code for studying rf wave propagation in toroidal magnetized plasmas

International Nuclear Information System (INIS)

Peysson, Y; Decker, J; Morini, L

2012-01-01

A new ray-tracing code named C3PO has been developed to study the propagation of arbitrary electromagnetic radio-frequency (rf) waves in magnetized toroidal plasmas. Its structure is designed for maximum flexibility regarding the choice of coordinate system and dielectric model. The versatility of this code makes it particularly suitable for integrated modeling systems. Using a coordinate system that reflects the nested structure of magnetic flux surfaces in tokamaks, fast and accurate calculations inside the plasma separatrix can be performed using analytical derivatives of a spline-Fourier interpolation of the axisymmetric toroidal MHD equilibrium. Applications to reverse field pinch magnetic configuration are also included. The effects of 3D perturbations of the axisymmetric toroidal MHD equilibrium, due to the discreteness of the magnetic coil system or plasma fluctuations in an original quasi-optical approach, are also studied. Using a Runge–Kutta–Fehlberg method for solving the set of ordinary differential equations, the ray-tracing code is extensively benchmarked against analytical models and other codes for lower hybrid and electron cyclotron waves. (paper)

Infrasonic ray tracing applied to mesoscale atmospheric structures: refraction by hurricanes.

Science.gov (United States)

Bedard, Alfred J; Jones, R Michael

2013-11-01

A ray-tracing program is used to estimate the refraction of infrasound by the temperature structure of the atmosphere and by hurricanes represented by a Rankine-combined vortex wind plus a temperature perturbation. Refraction by the hurricane winds is significant, giving rise to regions of focusing, defocusing, and virtual sources. The refraction of infrasound by the temperature anomaly associated with a hurricane is small, probably no larger than that from uncertainties in the wind field. The results are pertinent to interpreting ocean wave generated infrasound in the vicinities of tropical cyclones.

Study on method of characteristics based on cell modular ray tracing

International Nuclear Information System (INIS)

Tang Chuntao; Zhang Shaohong

2009-01-01

To address the issue of accurately solving neutron transport problem in complex geometry, method of characteristics (MOC) is studied in this paper, and a quite effective and memory saving cell modular ray tracing (CMRT) method is developed and related angle discretization and boundary condition handling issues are discussed. A CMRT based MOC code-PEACH is developed and tested against C5G7 MOX benchmark problem. Numerical results demonstrate that PEACH can give excellent accuracy for both k eff and pin power distribution for neutron transport problem. (authors)

Fast estimation of first-order scattering in a medical x-ray computed tomography scanner using a ray-tracing technique.

Science.gov (United States)

Liu, Xin

2014-01-01

This study describes a deterministic method for simulating the first-order scattering in a medical computed tomography scanner. The method was developed based on a physics model of x-ray photon interactions with matter and a ray tracing technique. The results from simulated scattering were compared to the ones from an actual scattering measurement. Two phantoms with homogeneous and heterogeneous material distributions were used in the scattering simulation and measurement. It was found that the simulated scatter profile was in agreement with the measurement result, with an average difference of 25% or less. Finally, tomographic images with artifacts caused by scatter were corrected based on the simulated scatter profiles. The image quality improved significantly.

Numerical Approximations to the Solution of Ray Tracing through the Crystalline Lens

International Nuclear Information System (INIS)

Yildirim, A.; Gökdoğan, A.; Merdan, M.; Lakshminarayanan, V.

2012-01-01

An approximate analytical solution in the form of a rapidly convergent series for tracing light rays through an inhomogeneous graded index medium is developed, using the multi-step differential transform method based on the classical differential transformation method. Numerical results are compared to those obtained by the fourth-order Runge—Kutta method to illustrate the precision and effectiveness of the proposed method. Results are given in explicit and graphical forms. (fundamental areas of phenomenology(including applications))

Trace metal determinations by total-reflection x-ray fluorescence analysis in the open Atlantic Ocean

International Nuclear Information System (INIS)

Schmidt, D.; Gerwinski, W.; Radke, I.

1993-01-01

The Intergovernmental Oceanographic Commission (IOC), as a major component of its programme ''Global Investigation of Pollution in the Marine Environment'' (GIPME), maintains a long-standing project on ''Open Ocean Baseline Studies of Trace Contaminants''. Initially, the Atlantic Ocean and trace metals were selected. Four deep-water stations in the Cape Basin, Angola Basin, Cape Verde Abyssal Plain and Seine Abyssal Plain were regularly sampled for at least 36 depths. Additional samples were taken between stations. Samples were distributed to participants and a similar number of additional laboratories. As a central part of our own contribution to the project, we determined the trace heavy metals manganese, nickel, copper, zinc and lead and the lighter selenium by total-reflection X-ray fluorescence analysis. For the TXRF, the pre-enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. Generally, very low levels of trace elements were found in filtered and unfiltered water samples from these remote areas of the open Atlantic Ocean. Typical examples of the distributions of trace metal concentrations on depth profiles from the four deep-water stations as well as intercomparisons between the stations are presented. (author)

HARPA: A versatile three-dimensional Hamiltonian ray-tracing program for acoustic waves in the atmosphere above irregular terrain

Science.gov (United States)

Jones, R. M.; Riley, J. P.; Georges, T. M.

1986-08-01

The modular FORTRAN 77 computer program traces the three-dimensional paths of acoustic rays through continuous model atmospheres by numerically integrating Hamilton's equations (a differential expression of Fermat's principle). The user specifies an atmospheric model by writing closed-form formulas for its three-dimensional wind and temperature (or sound speed) distribution, and by defining the height of the reflecting terrain vs. geographic latitude and longitude. Some general-purpose models are provided, or users can readily design their own. In addition to computing the geometry of each raypath, HARPA can calculate pulse travel time, phase time, Doppler shift (if the medium varies in time), absorption, and geometrical path length. The program prints a step-by-step account of a ray's progress. The 410-page documentation describes the ray-tracing equations and the structure of the program, and provides complete instructions, illustrated by a sample case.

Cosmic ray particle dosimetry and trajectory tracing

International Nuclear Information System (INIS)

Cruty, M.R.; Benton, E.V.; Turnbill, C.E.; Philpott, D.E.

1975-01-01

Five pocket mice (Perognathus longimembris) were flown on Apollo XVII, each with a solid-state (plastic) nuclear track detector implanted beneath its scalp. The subscalp detectors were sensitive to HZE cosmic ray particles with a LET greater than or approximately equal to 0.15 million electron volts per micrometer (MeV/micron). A critical aspect of the dosimetry of the experiment involved tracing individual particle trajectories through each mouse head from particle tracks registered in the individual subscalp detectors, thereby establishing a one-to-one correspondence between a trajectory location in the tissue and the presence or absence of a lesion. The other major aspect was the identification of each registered particle. An average of 16 particles with Z greater than or equal to 6 and 2.2 particles with Z greater than or equal to 20 were found per detector. The track density, 29 tracks/sq cm, when adjusted for detection volume, was in agreement with the photographic emulsion data from an area dosimeter located next to the flight package

Procedures for cryogenic X-ray ptychographic imaging of biological samples.

Science.gov (United States)

Yusuf, M; Zhang, F; Chen, B; Bhartiya, A; Cunnea, K; Wagner, U; Cacho-Nerin, F; Schwenke, J; Robinson, I K

2017-03-01

Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

Development of Ray Tracing Algorithms for Scanning Plane and Transverse Plane Analysis for Satellite Multibeam Application

Directory of Open Access Journals (Sweden)

N. H. Abd Rahman

2014-01-01

Full Text Available Reflector antennas have been widely used in many areas. In the implementation of parabolic reflector antenna for broadcasting satellite applications, it is essential for the spacecraft antenna to provide precise contoured beam to effectively serve the required region. For this purpose, combinations of more than one beam are required. Therefore, a tool utilizing ray tracing method is developed to calculate precise off-axis beams for multibeam antenna system. In the multibeam system, each beam will be fed from different feed positions to allow the main beam to be radiated at the exact direction on the coverage area. Thus, detailed study on caustics of a parabolic reflector antenna is performed and presented in this paper, which is to investigate the behaviour of the rays and its relation to various antenna parameters. In order to produce accurate data for the analysis, the caustic behaviours are investigated in two distinctive modes: scanning plane and transverse plane. This paper presents the detailed discussions on the derivation of the ray tracing algorithms, the establishment of the equations of caustic loci, and the verification of the method through calculation of radiation pattern.

Modeling UV Radiation Feedback from Massive Stars. I. Implementation of Adaptive Ray-tracing Method and Tests

Science.gov (United States)

Kim, Jeong-Gyu; Kim, Woong-Tae; Ostriker, Eve C.; Skinner, M. Aaron

2017-12-01

We present an implementation of an adaptive ray-tracing (ART) module in the Athena hydrodynamics code that accurately and efficiently handles the radiative transfer involving multiple point sources on a three-dimensional Cartesian grid. We adopt a recently proposed parallel algorithm that uses nonblocking, asynchronous MPI communications to accelerate transport of rays across the computational domain. We validate our implementation through several standard test problems, including the propagation of radiation in vacuum and the expansions of various types of H II regions. Additionally, scaling tests show that the cost of a full ray trace per source remains comparable to that of the hydrodynamics update on up to ∼ {10}3 processors. To demonstrate application of our ART implementation, we perform a simulation of star cluster formation in a marginally bound, turbulent cloud, finding that its star formation efficiency is 12% when both radiation pressure forces and photoionization by UV radiation are treated. We directly compare the radiation forces computed from the ART scheme with those from the M 1 closure relation. Although the ART and M 1 schemes yield similar results on large scales, the latter is unable to resolve the radiation field accurately near individual point sources.

Interior metric and ray-tracing map in the firework black-to-white hole transition

OpenAIRE

Rovelli, Carlo; Martin-Dussaud, Pierre

2018-01-01

The possibility that a black hole could tunnel into to white hole has recently received attention. Here we present a metric that improves the "firework" metric: it describes the entire process and solves the Einstein's equations everywhere except on a small transition surface that corresponds to the quantum tunneling. We compute the corresponding ray-tracing map from past infinity to future infinity explicitly.

Procedures for cryogenic X-ray ptychographic imaging of biological samples

Directory of Open Access Journals (Sweden)

M. Yusuf

2017-03-01

Full Text Available Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

Capturing sunlight into a photobioreactor: Ray tracing simulations of the propagation of light from capture to distribution into the reactor

NARCIS (Netherlands)

Zijffers, J.F.; Janssen, M.G.J.; Tramper, J.; Wijffels, R.H.; Salim, S.

2008-01-01

The Green Solar Collector (GSC), a photobioreactor designed for area efficient outdoor cultivation of microalgae uses Fresnel lenses and light guides to focus, transport and distribute direct light into the algae suspension. Calculating the path of rays of light, so-called ray tracing, is used to

Trace element analysis of single synthetic fibres by proton induced X-ray analysis in a helium atmosphere

International Nuclear Information System (INIS)

Ahmed, M.; Cookson, J.A.

1976-10-01

A technique for measuring the trace element content of synthetic fibres by detecting X-rays produced by 3 MeV proton bombardment has been developed. Largely to reduce the problems of removing heat from the fibres, an arrangement was used in which the beam was brought out of the vacuum into air or helium. Kapton, aluminium, nickel and molybdenum were tested for suitability as exit windows. Of these, aluminium produced significantly the most background in X-ray spectra while helium was found to be significantly better than air as the medium around the targets. With a kapton window, helium in the target chamber, and suitable collimation, trace element concentration down to a few parts per million could be measured when quantities of fibre of only a few times 10 -5 g were available for analysis. (author)

Mathematic models for a ray tracing method and its applications in wireless optical communications.

Science.gov (United States)

Zhang, Minglun; Zhang, Yangan; Yuan, Xueguang; Zhang, Jinnan

2010-08-16

This paper presents a new ray tracing method, which contains a whole set of mathematic models, and its validity is verified by simulations. In addition, both theoretical analysis and simulation results show that the computational complexity of the method is much lower than that of previous ones. Therefore, the method can be used to rapidly calculate the impulse response of wireless optical channels for complicated systems.

Linear scans of hair strands for trace elements by proton induced x-ray emission

International Nuclear Information System (INIS)

Jolly, R.K.; Pehrson, G.R.; Gupta, S.K.; Buckle, D.C.; Aceto, H. Jr.

1974-01-01

Hair strands obtained from school children in the 10 to 12 year age group were analyzed for trace element concentration as a function of distance from the root by proton-induced x-ray emission to study the history of exposure of the donors to toxic trace metals. These samples were collected from the vicinity of a copper smelter where high levels of As, Cd, Sb, and Pb have been noted. Scans show a continual build-up of Pb as a function of distance from the root, while As shows a reproducible and distinct maximum approximately 10 cm from the root. The concentration of Zn was found to be constant in all samples (without exception) to within the uncertainties of our measurements

Determination of trace elements in Katana (Japanese sword) by neutron activation analysis with multidimensional γ-ray spectrometry

International Nuclear Information System (INIS)

Okada, Y.; Hirai, S.; Ohya, S.; Kimura, Atsushi; Hatsukawa, Yuichi; Toh, Yosuke; Koizumi, Mitsuo; Oshima, Masumi

2006-01-01

In this study, we tried to measure trace elements (As and Sb) in Katana (Japanese swords) by multidimensional γ-ray spectrometry method (GEMINI-II) and conventional counting method for neutron activation analysis (NAA). The determined values by GEMINI-II and conventional counting were in good agreement with. Using the multidimensional γ-ray spectrometry (GEMINI-II) to determine As and Sb was improved by 7 times and 10 times compared with the conventional counting method. (author)

[Comparison of ocular modulation transfer function measurements by ray tracing wavefront technology and double-pass system].

Science.gov (United States)

Qiao, Liya; Cai, Xiaogu; Wan, Xiuhua; Guan, Zheng; Xiong, Ying; Lin, Zhong; Zhang, Ye; Tan, Jiaxuan; Wang, Ningli

2015-01-01

To compare the agreement of the ocular modulation transfer function (MTF) measured by double-pass system and ray tracing wavefront aberrometry, and to analyze the correlations of two MTFs with the visual acuity and contrast sensitivity function results. Comparative study. Subjects with no ocular diseases were consecutively enrolled in an epidemic study field located at the Dongyangzhuang Health Center, Yongnian County, Handan City, Hebei Province, China. After comprehensive ophthalmic examinations, the mean values of subtracted lower order aberration MTF at 5, 10, 15, 20, 25, and 30 cycle/degree(c/d) spatial frequencies were obtained with a double-pass system (optical quality analysis system II, OQAS II system) and a ray tracing wavefront aberrometer (iTrace visual function analyzer, iTrace system) in the 4.0 mm and 6.0 mm pupil after dilation, respectively. Paired-sample t test and Bland-Altman analysis were used to compare the difference and agreement of MTFs obtained with two instruments. Correlation analysis was preformed between two MTF measurement results and subjective visual quality including visual acuity and contrast sensitivity function. Two hundred and fifty-one healthy eyes of 163 subjects were enrolled, aged 30 to 60, mean (44.1 ± 9.7) years, including 139 eyes of 81 males and 112 eyes of 82 females. The mean value of MTF at 5, 10, 15, 20.25, 30 c/d obtained by iTrace in 4.0 mm pupil were 0.730 ± 0.138, 0.431 ± 0.159, 0.262 ± 0.120, 0.169 ± 0.078, 0.118 ± 0.053, 0.094 ± 0.043. The value obtained by OQASII were 0.347 ± 0.123, 0.162 ± 0.086, 0.072 ± 0.049, 0.042 ± 0.033, 0.026 ± 0.022, 0.017 ± 0.022, The result of iTrace were all significant higher than OQAS in both 4mm(t = 38.72, 28.03, 27.32, 27.59, 29.23, 28.96, P < 0.01) and 6.0 mm(t = 4.60, 3.19, 9.34, 13.41, 16.96, 20.24, P < 0.01)pupil diameter. The iTrace-OQAS II MTF difference was smaller in the 6.0 mm pupil. Bland-Altman analysis indicated that the agreement of two instruments was

Stepwise effects of the BCR sequential chemical extraction procedure on dissolution and metal release from common ferromagnesian clay minerals: A combined solution chemistry and X-ray powder diffraction study

Energy Technology Data Exchange (ETDEWEB)

Ryan, P.C. [Geology Department, Middlebury College, Middlebury, Vermont 05753 (United States)], E-mail: pryan@middlebury.edu; Hillier, S. [Macaulay Institute, Aberdeen, AB15 8QH UK (United Kingdom); Wall, A.J. [Department of Geosciences, Penn State University, University Park, Pennsylvania, 16802 (United States)

2008-12-15

Sequential extraction procedures (SEPs) are commonly used to determine speciation of trace metals in soils and sediments. However, the non-selectivity of reagents for targeted phases has remained a lingering concern. Furthermore, potentially reactive phases such as phyllosilicate clay minerals often contain trace metals in structural sites, and their reactivity has not been quantified. Accordingly, the objective of this study is to analyze the behavior of trace metal-bearing clay minerals exposed to the revised BCR 3-step plus aqua regia SEP. Mineral quantification based on stoichiometric analysis and quantitative powder X-ray diffraction (XRD) documents progressive dissolution of chlorite (CCa-2 ripidolite) and two varieties of smectite (SapCa-2 saponite and SWa-1 nontronite) during steps 1-3 of the BCR procedure. In total, 8 ({+-} 1) % of ripidolite, 19 ({+-} 1) % of saponite, and 19 ({+-} 3) % of nontronite (% mineral mass) dissolved during extractions assumed by many researchers to release trace metals from exchange sites, carbonates, hydroxides, sulfides and organic matter. For all three reference clays, release of Ni into solution is correlated with clay dissolution. Hydrolysis of relatively weak Mg-O bonds (362 kJ/mol) during all stages, reduction of Fe(III) during hydroxylamine hydrochloride extraction and oxidation of Fe(II) during hydrogen peroxide extraction are the main reasons for clay mineral dissolution. These findings underscore the need for precise mineral quantification when using SEPs to understand the origin/partitioning of trace metals with solid phases.

Combined Application of QEM-SEM and Hard X-ray Microscopy to Determine Mineralogical Associations and Chemcial Speciation of Trace Metals

Energy Technology Data Exchange (ETDEWEB)

M Grafe; M Landers; R Tappero; P Austin; B Gan; A Grabsch; C Klauber

2011-12-31

We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.

Biological X-ray absorption spectroscopy (BioXAS): a valuable tool for the study of trace elements in the life sciences.

Science.gov (United States)

Strange, Richard W; Feiters, Martin C

2008-10-01

Using X-ray absorption spectroscopy (XAS) the binding modes (type and number of ligands, distances and geometry) and oxidation states of metals and other trace elements in crystalline as well as non-crystalline samples can be revealed. The method may be applied to biological systems as a 'stand-alone' technique, but it is particularly powerful when used alongside other X-ray and spectroscopic techniques and computational approaches. In this review, we highlight how biological XAS is being used in concert with crystallography, spectroscopy and computational chemistry to study metalloproteins in crystals, and report recent applications on relatively rare trace elements utilised by living organisms and metals involved in neurodegenerative diseases.

Quantitative analysis of selected minor and trace elements through use of a computerized automatic x-ray spectrograph

International Nuclear Information System (INIS)

Fabbi, B.P.; Elsheimer, H.N.; Espos, L.F.

1976-01-01

Upgrading a manual X-ray spectrograph, interfacing with an 8K computer, and employment of interelement correction programs have resulted in a several-fold increase in productivity for routine quantitative analysis and an accompanying decrease in operator bias both in measurement procedures and in calculations. Factors such as dead time and self-absorption also are now computer corrected, resulting in improved accuracy. All conditions of analysis except for the X-ray tube voltage are controlled by the computer, which enhances precision of analysis. Elemental intensities are corrected for matrix effects, and from these the percent concentrations are calculated and printed via teletype. Interelement correction programs utilizing multiple linear regression are employed for the determination of the following minor and trace elements: K, S, Rb, Sr, Y, and Zr in silicate rocks, and Ba, As, Sb, and Zn in both silicate and carbonate rock samples. The last named elements use the same regression curves for both rock types. All these elements are determined in concentrations generally ranging from 0.0025 percent to 4.00 percent. The sensitivities obtainable range from 0.0001 percent for barium to 0.001 percent for antimony. The accuracy, as measured by the percent relative error for a variety of silicate and carbonate rocks, is on the order of 1-7 percent. The exception is yttrium

Application of a portable total reflection x-ray fluorescence spectrometer to a trace elemental analysis of wines

International Nuclear Information System (INIS)

Kunimura, Shinsuke; Kawai, Jun

2009-01-01

A portable total reflection X-ray fluorescence (TXRF) spectrometer has been applied to a trace elemental analysis of wines. Sulfur, K, Mn, Fe, and Rb were detected. These five elements were quantified by using 1 ppm of Co as an internal standard. The quantified concentrations ranged from sub-ppm to several hundred ppm. Because of organic substances in wines, the scattering of the incident X-rays from the dry residues of wines becomes strong. Therefore, a high spectral background appears in TXRF spectra of wines. Because of this background, relative standard deviations of the quantified concentrations were from 4 to 28%. Although the high spectral background appeared in the TXRF spectra of the wines, a detection limit down to several tens of ppb was achieved. The present portable spectrometer can be applied to screening for trace elements in wines before an accurate and precise analysis using a large elemental analyzer. (author)

Ray tracing for optimization of compound parabolic concentrators for solar collectors of enclosed design

OpenAIRE

YURCHENKO, VLADIMIR; YURCHENKO, EDUARD; ÇİYDEM, MEHMET; TOTUK, ONAT

2015-01-01

We present our developments in computer simulations and optimization of compound parabolic concentrators (CPCs) for solar heat collectors. Issues of both the optical and thermal optimization of CPC collectors of enclosed design are discussed. Ray tracing results for a CPC with a V-shaped absorber are presented. A range of optimal values for the apex angle of a V-shaped absorber is proposed for a CPC collector of typical design.

An efficient ray tracing method for propagation prediction along a mobile route in urban environments

Science.gov (United States)

Hussain, S.; Brennan, C.

2017-07-01

This paper presents an efficient ray tracing algorithm for propagation prediction in urban environments. The work presented in this paper builds upon previous work in which the maximum coverage area where rays can propagate after interaction with a wall or vertical edge is described by a lit polygon. The shadow regions formed by buildings within the lit polygon are described by shadow polygons. In this paper, the lit polygons of images are mapped to a coarse grid superimposed over the coverage area. This mapping reduces the active image tree significantly for a given receiver point to accelerate the ray finding process. The algorithm also presents an efficient method of quickly determining the valid ray segments for a mobile receiver moving along a linear trajectory. The validation results show considerable computation time reduction with good agreement between the simulated and measured data for propagation prediction in large urban environments.

A FORMALISM FOR COVARIANT POLARIZED RADIATIVE TRANSPORT BY RAY TRACING

International Nuclear Information System (INIS)

Gammie, Charles F.; Leung, Po Kin

2012-01-01

We write down a covariant formalism for polarized radiative transfer appropriate for ray tracing through a turbulent plasma. The polarized radiation field is represented by the polarization tensor (coherency matrix) N αβ ≡ (a α k a* β k ), where a k is a Fourier coefficient for the vector potential. Using Maxwell's equations, the Liouville-Vlasov equation, and the WKB approximation, we show that the transport equation in vacuo is k μ ∇ μ N αβ = 0. We show that this is equivalent to Broderick and Blandford's formalism based on invariant Stokes parameters and a rotation coefficient, and suggest a modification that may reduce truncation error in some situations. Finally, we write down several alternative approaches to integrating the transfer equation.

An analysis of options available for developing a common laser ray tracing package for Ares and Kull code frameworks

Energy Technology Data Exchange (ETDEWEB)

Weeratunga, S K

2008-11-06

Ares and Kull are mature code frameworks that support ALE hydrodynamics for a variety of HEDP applications at LLNL, using two widely different meshing approaches. While Ares is based on a 2-D/3-D block-structured mesh data base, Kull is designed to support unstructured, arbitrary polygonal/polyhedral meshes. In addition, both frameworks are capable of running applications on large, distributed-memory parallel machines. Currently, both these frameworks separately support assorted collections of physics packages related to HEDP, including one for the energy deposition by laser/ion-beam ray tracing. This study analyzes the options available for developing a common laser/ion-beam ray tracing package that can be easily shared between these two code frameworks and concludes with a set of recommendations for its development.

Comparison and Extension of Existing 3D Propagation Models with Real-World Effects Based on Ray-tracing

DEFF Research Database (Denmark)

Kifle, Dereje W.; Gimenez, Lucas Chavarria; Wegmann, Bernhard

2014-01-01

antenna beam orientation like antenna tilting or when users are distributed in the third dimension (height) in multi-floor scenarios. Ray tracing based generated propagation maps that show the realistic propagation effect are used as 3D real world reference for investigation and model approval....

Alpha particle excited x-ray fluorescence analysis for trace elements in cervical spinal cords of amyotrophic lateral sclerosis

International Nuclear Information System (INIS)

Mizumoto, Yoshihiko; Iwata, Shiro; Sasajima, Kazuhisa; Yase, Yoshio; Yoshida, Shohei.

1980-01-01

The mean contents of trace elements in anterior gray horn section of cervical spinal cords of six amyotrophic lateral sclerosis (ALS) cases were relatively determined against those of six control cases by α-particle excited X-ray fluorescence analysis. The anterior gray horn section of cervical spinal cord samples were excited by 1.6 MeV α-particle beam of 2 mm diameter accelerated with a Van de Graaff accelerator, and characteristic X-ray spectra were measured with a Si(Li) detector. From the peak areas on the X-ray spectra, the relative mean contents of the trace elements in cervical spinal cords of ALS and control cases were determined. As a result, the X-ray peaks of Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Cu and Zn were detected. The contents of Al, Si, P, Ca, Ti, V, Mn and Fe in ALS cases were higher than those in control cases. The contents of S, Cl, K, Cu and Zn in ALS and in control cases were equal to each other within standard deviation. The precipitation mechanisms of Al, Si, P, Ca, Ti, V, Mn and Fe into cervical spinal cord of ALS cases are discussed on the basis of the previous studies. (author)

Update of X ray and gamma ray decay data standards for detector calibration and other applications. V. 2: Data selection, assessment and evaluation procedures

International Nuclear Information System (INIS)

2007-05-01

Various factors such as source preparation and source detector geometry may affect the quality of measurements made with intrinsic germanium and other γ ray spectrometers. However, the accuracy of such measurements invariably depends on the accuracy of the efficiency versus energy calibration curve and hence on the accuracy of the decay data for the radionuclides from which calibration standard sources are prepared. Both half-lives and X and γ ray emission probabilities need to be known to good accuracy. The recommendations and report of this work are published in two volumes: Volume 1 - Recommended Decay Data, High Energy Gamma Ray Standards and Angular Correlation Coefficients; Volume 2 - Data Selection, Assessment and Evaluation Procedures. Volume 1 is a self-contained assembly of the recommended decay data covering half-lives and the X ray and γ ray emission probabilities of the selected radionuclides, and listings of various high energy γ ray standards and a set of angular correlation coefficients; these data are presented in a concise manner for rapid and easy access. More detailed technical features of the CRP are described in Volume 2, including the evaluation procedures adopted and extensive traceable explanations of the origins of the nuclear data used to produce the recommended values listed in Volume 1. This detail was judged to be essential in order to record and demonstrate the quality of the resulting data files and allow the reader to trace the origins of the nuclear data used to determine the recommended values. All evaluations were based on the available experimental data, supplemented with the judicious use of well established theory. Three types of data (half-lives, energies and emission probabilities) were compiled and evaluated (Annex II). Consideration was also given to the adoption of a number of prompt high energy γ rays from specific nuclear reactions (Annex III), as well as to using the γ-γ coincidence technique for efficiency

Ray-tracing analysis of electron-cyclotron-resonance heating in straight stellarators

International Nuclear Information System (INIS)

Kato, K.

1983-05-01

A ray-tracing computer code is developed and implemented to simulate electron cyclotron resonance heating (ECRH) in stellarators. A straight stellarator model is developed to simulate the confinement geometry. Following a review of ECRH, a cold plasma model is used to define the dispersion relation. To calculate the wave power deposition, a finite temperature damping approximation is used. 3-D ray equations in cylindrical coordinates are derived and put into suitable forms for computation. The three computer codes, MAC, HERA, and GROUT, developed for this research, are described next. ECRH simulation is then carried out for three models including Heliotron E and Wendelstein VII A. Investigated aspects include launching position and mode scan, frequency detuning, helical effects, start-up, and toroidal effects. Results indicate: (1) an elliptical waveguide radiation pattern, with its long axis oriented half-way between the toroidal axis and the saddle point line, is more efficient than a circular one; and (2) mid-plane, high field side launch is favored for both O- and X-waves

LA-ICP-MS for Trace Analysis of Long-Lived Radionuclides in Solid Non-conducting Radioactive Waste Samples

International Nuclear Information System (INIS)

Becker, J.S.; Gastel, M.; Tenzler, D.; Dietze, H.J.

1999-01-01

The characterization of radioactive waste materials from nuclear reactors for recycling and final storage requires fast, sensitive and precise analytical methods, which are able to determine long-lived radionuclidic ultra traces in a short time. For the determination of long-lived α and β ray-emitting nuclides besides the classical radiochemical methods which are mostly include time-consuming radiochemical separation procedures, to an increasing extent inductively coupled plasma mass spectrometry (ICP-MS) has been used successfully as a powerful trace, ultra trace and isotopic analytical method for the determination of long-lived radionuclides in aqueous solutions [1-3

Trace elements in tobacco and tobacco smoke by x-ray fluorescence technique

International Nuclear Information System (INIS)

Mishra, U.C.; Shaikh, G.N.; Sadasivan, S.

1986-01-01

Trace elements in tobacco and tobacco smoke of a large number of commonly available brands of cigarettes were analyzed by energy dispersive x-ray fluorescence. This work supplements the data on the same samples gathered by INAA and reported earlier. Data on some toxic elements like Pb, Cu and Ni that could not be measured by INAA are presented. A number of chewing and snuff tobacco samples were also analyzed. The concentrations of Ca, K, Cl, Br, Cu, Fe, Ni, Pb, Rb, Sr, Ti and Zn in all these samples are presented and their relative hazards are discussed. (author)

An automated background estimation procedure for gamma ray spectra

International Nuclear Information System (INIS)

Tervo, R.J.; Kennett, T.J.; Prestwich, W.V.

1983-01-01

An objective and simple method has been developed to estimate the background continuum in Ge gamma ray spectra. Requiring no special procedures, the method is readily automated. Based upon the inherent statistical properties of the experimental data itself, nodes, which reflect background samples are located and used to produce an estimate of the continuum. A simple procedure to interpolate between nodes is reported and a range of rather typical experimental data is presented. All information necessary to implemented this technique is given including the relevant properties of various factors involved in its development. (orig.)

Blood selenium content determination by X-ray fluorescence

International Nuclear Information System (INIS)

Mainardi, R.T.

1987-01-01

The presence of some elements in small amounts (traces) in the human body is of foremost importance for the prevention and treatment of several diseases. It has been recently shown that traces of selenium in blood are closely related to the occurrence of miotonic distrophy, a muscular disease that is affecting a significant percentage of the population. This work describes a simple procedure to determine selenium in human blood serum by energy dispersive X-ray fluorescence analysis. Final quantification is achieved through the addition of titanium as an internal standard. (Author) [es

Trace element distribution in different chemical fractions of False Bay sediments

International Nuclear Information System (INIS)

Rosental, R.

1984-05-01

Trace metals in the aquatic environment are generally concentrated on solid geochemical phases which eventually become incorporated into estuarine and marine sediments. The mechanism of trace metal concentration is believed to be adsorption on various geochemical phases, such as hydrous metal oxides, clays and organic matter. Metals in estuarine sediments can thus be expected to be partitioned between different phases, depending on the concentration of the phase and the strength of the adsorption bond. The bioavailability of sediment-bound metals to deposit-feeding organisms will depend on trace metal partitioning and the kinetics of biological metal uptake from each geochemical phase. The major objective of this study was to establish an analytical procedure involving sequential chemical extractions for the partitioning of particulate trace metals in sediment samples, collected from False Bay. Eight metals were examined, i.e. Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn. X-ray diffraction was also used in the study

MCViNE – An object oriented Monte Carlo neutron ray tracing simulation package

Energy Technology Data Exchange (ETDEWEB)

Lin, Jiao Y.Y., E-mail: linjiao@ornl.gov [Caltech Center for Advanced Computing Research, California Institute of Technology (United States); Department of Applied Physics and Materials Science, California Institute of Technology (United States); Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory (United States); Smith, Hillary L. [Department of Applied Physics and Materials Science, California Institute of Technology (United States); Granroth, Garrett E., E-mail: granrothge@ornl.gov [Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory (United States); Abernathy, Douglas L.; Lumsden, Mark D.; Winn, Barry; Aczel, Adam A. [Quantum Condensed Matter Division, Oak Ridge National Laboratory (United States); Aivazis, Michael [Caltech Center for Advanced Computing Research, California Institute of Technology (United States); Fultz, Brent, E-mail: btf@caltech.edu [Department of Applied Physics and Materials Science, California Institute of Technology (United States)

2016-02-21

MCViNE (Monte-Carlo VIrtual Neutron Experiment) is an open-source Monte Carlo (MC) neutron ray-tracing software for performing computer modeling and simulations that mirror real neutron scattering experiments. We exploited the close similarity between how instrument components are designed and operated and how such components can be modeled in software. For example we used object oriented programming concepts for representing neutron scatterers and detector systems, and recursive algorithms for implementing multiple scattering. Combining these features together in MCViNE allows one to handle sophisticated neutron scattering problems in modern instruments, including, for example, neutron detection by complex detector systems, and single and multiple scattering events in a variety of samples and sample environments. In addition, MCViNE can use simulation components from linear-chain-based MC ray tracing packages which facilitates porting instrument models from those codes. Furthermore it allows for components written solely in Python, which expedites prototyping of new components. These developments have enabled detailed simulations of neutron scattering experiments, with non-trivial samples, for time-of-flight inelastic instruments at the Spallation Neutron Source. Examples of such simulations for powder and single-crystal samples with various scattering kernels, including kernels for phonon and magnon scattering, are presented. With simulations that closely reproduce experimental results, scattering mechanisms can be turned on and off to determine how they contribute to the measured scattering intensities, improving our understanding of the underlying physics.

Programs and procedures for assessing quality of spectral gamma-ray borehole data for the UGTA

International Nuclear Information System (INIS)

Conaway, J.G.

1998-01-01

This report describes the procedures and computer programs used to process spectral gamma-ray borehole logging data in the UGTA (UnderGround Test Area) program at the NTS (Nevada Test Site) to assess data quality. These programs and procedures were used to analyze data from five boreholes in the UGTA program. Development of these computer programs and procedures required considerable effort and the primary purpose of this report is to provide continuity with future activities related to spectral gamma-ray borehole logging in the UGTA program. This is especially important because of the long time interval between cessation of logging in April, 1996 and the next round of activity, which has not yet occurred. This report should also be useful if any quality control issues arise regarding past or forthcoming spectral gamma-ray log analyses. In the characterization work underway at the Nevada Test Site Underground Test Area, the logging contractor, Western Atlas, agreed to identify five artificial nuclides based on their gamma-ray signatures. Those nuclides are 60 Co, 106 Ru, 125 Sb, 134 Cs, and 137 Cs. In the case of 106 Ru, which is not a gamma emitter, any detected gamma rays come from the daughter nuclide 106 Rh which has a half-life of 30 s. With such a short half-life, 106 Rh can be considered to be in equilibrium with 106 Ru under most conditions so the result is the same as if the gamma rays were emitted by the 106 Ru. The Western Atlas spectral gamma-ray curve plots from a given borehole present detailed qualitative information on the apparent distribution of natural and artificial nuclides with depth in the borehole. The computer programs and procedures described in this report were used to provide a quality analysis of the contractor's processed data and to work with the contractor to validate and/or refine their existing automatic processing. This was done using a procedure that was developed and tested successfully in earlier work at the NTS; the revised

Global Calibration of Multi-Cameras Based on Refractive Projection and Ray Tracing

Directory of Open Access Journals (Sweden)

Mingchi Feng

2017-10-01

Full Text Available Multi-camera systems are widely applied in the three dimensional (3D computer vision, especially when multiple cameras are distributed on both sides of the measured object. The calibration methods of multi-camera systems are critical to the accuracy of vision measurement and the key is to find an appropriate calibration target. In this paper, a high-precision camera calibration method for multi-camera systems based on transparent glass checkerboards and ray tracing is described, and is used to calibrate multiple cameras distributed on both sides of the glass checkerboard. Firstly, the intrinsic parameters of each camera are obtained by Zhang’s calibration method. Then, multiple cameras capture several images from the front and back of the glass checkerboard with different orientations, and all images contain distinct grid corners. As the cameras on one side are not affected by the refraction of glass checkerboard, extrinsic parameters can be directly calculated. However, the cameras on the other side are influenced by the refraction of glass checkerboard, and the direct use of projection model will produce a calibration error. A multi-camera calibration method using refractive projection model and ray tracing is developed to eliminate this error. Furthermore, both synthetic and real data are employed to validate the proposed approach. The experimental results of refractive calibration show that the error of the 3D reconstruction is smaller than 0.2 mm, the relative errors of both rotation and translation are less than 0.014%, and the mean and standard deviation of reprojection error of the four-camera system are 0.00007 and 0.4543 pixels, respectively. The proposed method is flexible, highly accurate, and simple to carry out.

Determination of some trace elements in biological samples using XRF and TXRF techniques

International Nuclear Information System (INIS)

Khuder, A.; Karjou, J.; Sawan, M. K.

2006-07-01

XRF and TXRF techniques were successfully used for the multi-element determination of trace elements in whole blood and human head hair samples. This was achieved by the direct analysis using XRF technique with different collimation units and by the optimized chemical procedures for TXRF analysis. Light element of S and P were preferably determined by XRF with primary x-ray excitation, while, elements of K, Ca, Fe, and Br were determined with a very good accuracy and precision using XRF with Cu- and Mo-secondary targets. The chemical procedure dependent on the preconcentration of trace elements by APDC was superiorly used for the determination of traces of Ni and Pb in the range of 1.0-1.7 μg/dl and 11-23 μg/dl, respectively, in whole blood samples by TXRF technique; determination of other elements as Cu and Zn was also achievable using this approach. Rb in whole blood samples was determined directly after the digestion of samples using PTFE-bomb for TXRF analysis. (author)

Analysis of trace elements in opal using PIXE

Energy Technology Data Exchange (ETDEWEB)

Hinrichs, Ruth, E-mail: ruth.hinrichs@ufrgs.br [Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Bertol, A.P.L. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Vasconcellos, M.A.Z. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Instituto de Física, UFRGS, Porto Alegre, RS (Brazil)

2015-11-15

Particle induced X-ray emission (PIXE) analysis is particularly important for the analysis of trace elements of precious samples, being one of the few methods to determine elements with ppm concentration that does not affect sample integrity. A PIXE methodology for trace element analysis in opal was developed. To avoid detector count saturation due to the high number of Si-Kα X-rays generated in the sample, several filters were employed to optimize the reduction of the Si-Kα signal, while maintaining acceptable intensities of the other relevant X-ray lines. Two proton beam energies were tested, to establish the signal to noise ratio in different X-ray energies. Spectra were fitted with the software GUPIX, using a matrix composition determined with electron beam excited energy dispersive X-ray spectrometry. Above the energy of the silicon X-ray, several trace elements were quantified.

Bureau of radiological health compliance testing procedures for cabinet S-ray systems

International Nuclear Information System (INIS)

Miller, E.A.; Sprau, D.

1976-01-01

A manual has been developed by the Bureau of Radiological Health of the Food and Drug Administration to establish procedures for the routine field testing of cabinet x-ray systems to determine compliance with the Federal Performance Standard for Cabinet X-Ray Systems, 21 CFR 1020.40. The manual provides specific instructions for testing each model of cabinet x-ray system. Results from the inspection are recorded on a data from which is designed to permit automatic data processing

Trace metal contaminants in sediments and soils: comparison between ICP and XRF quantitative determination

Directory of Open Access Journals (Sweden)

Congiu A.

2013-04-01

Full Text Available A mineralization method HCl-free for heavy metals analysis in sediments and soils by DRC-ICP-MS was developed. The procedure, which uses concentrated nitric, hydrofluoric acid and hydrogen peroxide, was applied for the analysis of arsenic, cadmium, chromium, nickel and vanadium. The same samples were then analyzed, as pressed pellets, by wavelength dispersive X ray fluorescence (WD-XRF using the dedicated PANalytical Pro Trace solution for the determination of trace elements. Comparison of ICP and XRF data showed good agreement for the elements under investigation, unless for chromium in soils, which recovery was not complete.

Chronocoulometric determination of trace levels of uranium in rocks

International Nuclear Information System (INIS)

Cantagallo, M.I.C.; Gutz, I.G.R.

1990-01-01

The chronocoulometric method for the determination of trace levels of uranium, based on the catalytic nitrate reduction was applied with real and synthetic samples. Reference materials with complex matrices like rocks were first solubilized by hot digestion under pressure in a PTFE bomb. When necessary, an adapted liquid-liquid extraction procedure was used for previous separation of interferents. The obtained results are in good agreement with the values obtained with other techniques such as X-ray fluorescence, mass spectrometry -isotope dilution and apithermal activation analysis. (author) [pt

Three-dimensional ray tracing for refractive correction of human eye ametropies

Science.gov (United States)

Jimenez-Hernandez, J. A.; Diaz-Gonzalez, G.; Trujillo-Romero, F.; Iturbe-Castillo, M. D.; Juarez-Salazar, R.; Santiago-Alvarado, A.

2016-09-01

Ametropies of the human eye, are refractive defects hampering the correct imaging on the retina. The most common ways to correct them is by means of spectacles, contact lenses, and modern methods as laser surgery. However, in any case it is very important to identify the ametropia grade for designing the optimum correction action. In the case of laser surgery, it is necessary to define a new shape of the cornea in order to obtain the wanted refractive correction. Therefore, a computational tool to calculate the focal length of the optical system of the eye versus variations on its geometrical parameters is required. Additionally, a clear and understandable visualization of the evaluation process is desirable. In this work, a model of the human eye based on geometrical optics principles is presented. Simulations of light rays coming from a punctual source at six meter from the cornea are shown. We perform a ray-tracing in three dimensions in order to visualize the focusing regions and estimate the power of the optical system. The common parameters of ametropies can be easily modified and analyzed in the simulation by an intuitive graphic user interface.

Assessment of organ doses by standard X-ray procedures in the GDR

International Nuclear Information System (INIS)

Tautz, M.; Brandt, G.A.

1986-01-01

A modern method has been described to assess the radiation burden by X-ray procedures with consideration of the standards of our Society for Medical Radiology in the GDR. The underlying methodology is a Monte Carlo computer technique, which simulates stochastically the energy deposition of X-ray photons in a mathematically described heterogeneous anthropomorphic phantom by Rosenstein (US Department of Health, Education and Welfare). To apply the procedure specific values for the following parameters must be determined for each dose estimation: projection and view, X-ray field size and location entrance exposure at skin surface, beam quality, source-to-image receptor distance. The base data are obtained in terms of tissue-air ratio. Organ doses were calculated for chest, urography, skull, cervical spine, thoracic spine, lumbar spine, pelvis and lymphography. Concluding possibilities have been discussed for reduction of radiation burden. 9 refs., 6 figs., 9 tabs. (author)

Multiplexed optical data storage and vectorial ray tracing

Directory of Open Access Journals (Sweden)

Foreman M.R.

2010-06-01

Full Text Available With the motivation of creating a terabyte-sized optical disk, a novel imaging technique is implemented. This technique merges two existing technologies: confocal microscopy and Mueller matrix imaging. Mueller matrix images from a high numerical space are obtained. The acquisition of these images makes the exploration of polarisation properties in a sample possible. The particular case of optical data storage is used as an example in this presentation. Since we encode information into asymmetric datapits (see Figure 1, the study of the polarisation of the scattered light can then be used to recover the orientation of the pit. It is thus possible to multiplex information by changing the angle of the mark. The storage capacity in the system is hence limited by the number of distinct angles that the optical system can resolve. This presentation thus answers the question; what is the current storage capacity of a polarisation sensitive optical disk? After a brief introduction to polarisation, the decoding method and experimental results are presented so as to provide an answer to this question. With the aim of understanding high NA focusing, an introduction to vectorial ray tracing is then given.

Rapid determination of trace phosphorus, sulfur, chlorine, bromine and iodine by energy dispersive X-ray fluorescence analysis with monochromatic excitations

International Nuclear Information System (INIS)

Wakisaka, Tatsushi; Morita, Naoki; Hirabayashi, Tadashi; Nakahara, Taketoshi

1998-01-01

A useful and rapid procedure is described for the determination of trace phosphorus, sulfur, chlorine, bromine, and iodine by means of an energy dispersive X-ray fluorescence spectrometer (EDXRF) with monochromatic excitations. Using monochromatic excitations, the detection limits for phosphorus, sulfur, chlorine (Cr-Kα, 5.41 keV), bromine (Mo-Kα, 17.44 keV), and iodine (W-continuum, 40 keV) were found to be 4.6, 1.7, 0.7, 0.09 and 0.5 μg g -1 , respectively. The relative standard deviations in five replicate measurements were 0.9-1.3%. The proposed method was applied to the direct determination of sulfur in the NIST Residual Fuel Oil, and others. The results obtained by the proposed method were in good agreement with the certified values. Bromine in a seawater sample, as well as iodine and bromine in a brine sample were determined by the proposed method. The obtained results were in good agreement with those obtained by ion chromatography. (author)

Non-destructive trace element microanalysis of as-received cometary nucleus samples using synchrotron x ray fluorescence

International Nuclear Information System (INIS)

Sutton, S.R.

1989-01-01

The Synchrotron X ray Fluorescence (SXRF) microprobe at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, will be an excellent instrument for non-destructive trace element analyses of cometary nucleus samples. Trace element analyses of as-received cometary nucleus material will also be possible with this technique. Bulk analysis of relatively volatile elements will be important in establishing comet formation conditions. However, as demonstrated for meteorites, microanalyses of individual phases in their petrographic context are crucial in defining the histories of particular components in unequilibrated specimens. Perhaps most informative in comparing cometary material with meteorites will be the halogens and trace metals. In-situ, high spatial resolution microanalyses will be essential in establishing host phases for these elements and identifying terrestrial (collection/processing) overprints. The present SXRF microprobe is a simple, yet powerful, instrument in which specimens are excited with filtered, continuum synchrotron radiation from a bending magnet on a 2.5 GeV electron storage ring. A refrigerated cell will be constructed to permit analyses at low temperatures. The cell will consist essentially of an air tight housing with a cold stage. Kapton windows will be used to allow the incident synchrotron beam to enter the cell and fluorescent x rays to exit it. The cell will be either under vacuum or continuous purge by ultrapure helium during analyses. Several other improvements of the NSLS microprobe will be made prior to the cometary nucleus sample return mission that will greatly enhance the sensitivity of the technique

Accounting for partiality in serial crystallography using ray-tracing principles.

Science.gov (United States)

Kroon-Batenburg, Loes M J; Schreurs, Antoine M M; Ravelli, Raimond B G; Gros, Piet

2015-09-01

Serial crystallography generates `still' diffraction data sets that are composed of single diffraction images obtained from a large number of crystals arbitrarily oriented in the X-ray beam. Estimation of the reflection partialities, which accounts for the expected observed fractions of diffraction intensities, has so far been problematic. In this paper, a method is derived for modelling the partialities by making use of the ray-tracing diffraction-integration method EVAL. The method estimates partialities based on crystal mosaicity, beam divergence, wavelength dispersion, crystal size and the interference function, accounting for crystallite size. It is shown that modelling of each reflection by a distribution of interference-function weighted rays yields a `still' Lorentz factor. Still data are compared with a conventional rotation data set collected from a single lysozyme crystal. Overall, the presented still integration method improves the data quality markedly. The R factor of the still data compared with the rotation data decreases from 26% using a Monte Carlo approach to 12% after applying the Lorentz correction, to 5.3% when estimating partialities by EVAL and finally to 4.7% after post-refinement. The merging R(int) factor of the still data improves from 105 to 56% but remains high. This suggests that the accuracy of the model parameters could be further improved. However, with a multiplicity of around 40 and an R(int) of ∼50% the merged still data approximate the quality of the rotation data. The presented integration method suitably accounts for the partiality of the observed intensities in still diffraction data, which is a critical step to improve data quality in serial crystallography.

Ray-tracing techniques to assess the electromagnetic field radiated by radio base stations: Application and experimental validation in an urban environment

International Nuclear Information System (INIS)

Adda, S.; Anglesio, L.; D'Amore, G.; Mantovan, M.; Menegolli, M.

2004-01-01

This paper aims to validate a ray-tracing model for electromagnetic field calculation, which is used in urban environments to predict irradiation from radio base stations for population exposure evaluation. Validation was carried out through a measurement campaign by choosing measurement points in order to test different propagation environments and analysing broadcast control channels through narrow band measurements. Comparison of the calculated and measured fields indicates that the ray-tracing model used calculates electric field with good accuracy, in spite of the fact that the propagation environment is not described in detail, because of difficulties in modelling the geometrical and electrical characteristics of urban areas. Differences between the calculated and measured results remain below 1.5 dB, with a mean value of 1 dB. (authors)

Collective effective dose in Europe from x-ray and nuclear medicine procedures

International Nuclear Information System (INIS)

Bly, R.; Jaervinen, H.; Jahnen, A.; Olerud, H.; Vassileva, J.; Vogiatzi, S.

2015-01-01

Population doses from radiodiagnostic (X-ray and nuclear medicine) procedures in Europe were estimated based on data collected from 36 European countries. For X-ray procedures in EU and EFTA countries (except Liechtenstein) the collective effective dose is 547 500 man Sv, resulting in a mean effective dose of 1.06 mSv per caput. For all European countries included in the survey the collective effective dose is 605 000 man Sv, resulting in a mean effective dose of 1.05 mSv per caput. For nuclear medicine procedures in EU countries and EFTA (except Liechtenstein) countries the collective effective dose is 30 700 man Sv, resulting in a mean effective dose of 0.06 mSv per caput. For all European countries included in the survey the collective effective dose is 31 100 man Sv, resulting in a mean effective dose of 0.05 mSv per caput. (authors)

75 FR 10460 - Improving Tracing Procedures for E. coli O157:H7 Positive Raw Beef Product

Science.gov (United States)

2010-03-08

... Tracing Procedures for E. coli O157:H7 Positive Raw Beef Product AGENCY: Food Safety and Inspection... has found positive for Escherichia coli (E. coli) O157:H7. FSIS will also discuss additional verification activities the Agency will conduct at suppliers in response to positive E. coli O157:H7 results...

Ray Tracing through the Edge Focusing of Rectangular Benders and an Improved Model for the Los Alamos Proton Storage Ring

Energy Technology Data Exchange (ETDEWEB)

Kolski, Jeffrey S. [Los Alamos National Laboratory; Barlow, David B. [Los Alamos National Laboratory; Macek, Robert J. [Los Alamos National Laboratory; McCrady, Rodney C. [Los Alamos National Laboratory

2011-01-01

Particle ray tracing through simulated 3D magnetic fields was executed to investigate the effective quadrupole strength of the edge focusing of the rectangular bending magnets in the Los Alamos Proton Storage Ring (PSR). The particle rays receive a kick in the edge field of the rectangular dipole. A focal length may be calculated from the particle tracking and related to the fringe field integral (FINT) model parameter. This tech note introduces the baseline lattice model of the PSR and motivates the need for an improvement in the baseline model's vertical tune prediction, which differs from measurement by .05. An improved model of the PSR is created by modifying the fringe field integral parameter to those suggested by the ray tracing investigation. This improved model is then verified against measurement at the nominal PSR operating set point and at set points far away from the nominal operating conditions. Lastly, Linear Optics from Closed Orbits (LOCO) is employed in an orbit response matrix method for model improvement to verify the quadrupole strengths of the improved model.

The skew ray ambiguity in the analysis of videokeratoscopic data.

Science.gov (United States)

Iskander, D Robert; Davis, Brett A; Collins, Michael J

2007-05-01

Skew ray ambiguity is present in most videokeratoscopic measurements when azimuthal components of the corneal curvature are not taken into account. There have been some reported studies based on theoretical predictions and measured test surfaces suggesting that skew ray ambiguity is significant for highly deformed corneas or decentered corneal measurements. However, the effect of skew ray ambiguity in ray tracing through videokeratoscopic data has not been studied in depth. We have evaluated the significance of the skew ray ambiguity and its effect on the analyzed corneal optics. This has been achieved by devising a procedure in which we compared the corneal wavefront aberrations estimated from 3D ray tracing with those determined from 2D (meridional based) estimates of the refractive power. The latter was possible due to recently developed concept of refractive Zernike power polynomials which links the refractive power domain with that of the wavefront. Simulated corneal surfaces as well as data from a range of corneas (from two different Placido disk-based videokeratoscopes) were used to find the limit at which the difference in estimated corneal wavefronts (or the corresponding refractive powers) would have clinical significance (e.g., equivalent to 0.125 D or more). The inclusion/exclusion of the skew ray in the analyses showed some differences in the results. However, the proposed procedure showed clinically significant differences only for highly deformed corneas and only for large corneal diameters. For the overwhelming majority of surfaces, the skew ray ambiguity is not a clinically significant issue in the analysis of the videokeratoscopic data indicating that the meridional processing such as that encountered in calculation of the refractive power maps is adequate.

Trace element measurements with synchrotron radiation

International Nuclear Information System (INIS)

Hanson, A.L.; Kraner, H.W.; Jones, K.W.; Gordon, B.M.; Mills, R.E.

1982-01-01

Aspects of the application of synchrotron radiation to trace element determinations by x-ray fluorescence have been investigated using beams from the Cornell facility, CHESS. Fluoresced x rays were detected with a Si(Li) detector placed 4 cm from the target at 90 0 to the beam. Thick samples of NBS Standard Reference Materials were used to calibrate trace element sensitivity and estimate minimum detectable limits for this method

Proton induced x-ray emission analysis of trace elements in thick bread samples

International Nuclear Information System (INIS)

Mohamed Baker Al-bedri; Ikram Jameel Abdul Ghani; Ibrahim Abdul Rahman Al-aghil

2009-01-01

Proton induced X-ray emission (PIXE) technique has been used for identification and quantitative analysis of the elemental concentration in thick bread samples. Bread samples were air-oven dried at 60degC and milled in a clean agate mortar to homogenize the sample and pressed into a pellet. PIXE technique relies on the analysis of the energy spectra of the characteristic X-ray emitted from the thick bread sample and the orchard leaf standard (NIST-SRM-1571) bombarded with 2.0 MeV protons. The concentration of the elements (Cl, K, Ca, Mn, Fe, Cu, and Zn) in the bread samples was determined by comparison with NIST orchard leaf standard. The accuracy of the measurements ranged between ±2% and ±10% for the most elements detected in this method. The aim of this study is to establish the reference concentration of trace elements in the Iraqi bread using PIXE technique. (author)

Integration of Monte-Carlo ray tracing with a stochastic optimisation method: application to the design of solar receiver geometry.

Science.gov (United States)

Asselineau, Charles-Alexis; Zapata, Jose; Pye, John

2015-06-01

A stochastic optimisation method adapted to illumination and radiative heat transfer problems involving Monte-Carlo ray-tracing is presented. A solar receiver shape optimisation case study illustrates the advantages of the method and its potential: efficient receivers are identified using a moderate computational cost.

Automatic segmentation of rotational x-ray images for anatomic intra-procedural surface generation in atrial fibrillation ablation procedures.

Science.gov (United States)

Manzke, Robert; Meyer, Carsten; Ecabert, Olivier; Peters, Jochen; Noordhoek, Niels J; Thiagalingam, Aravinda; Reddy, Vivek Y; Chan, Raymond C; Weese, Jürgen

2010-02-01

Since the introduction of 3-D rotational X-ray imaging, protocols for 3-D rotational coronary artery imaging have become widely available in routine clinical practice. Intra-procedural cardiac imaging in a computed tomography (CT)-like fashion has been particularly compelling due to the reduction of clinical overhead and ability to characterize anatomy at the time of intervention. We previously introduced a clinically feasible approach for imaging the left atrium and pulmonary veins (LAPVs) with short contrast bolus injections and scan times of approximately 4 -10 s. The resulting data have sufficient image quality for intra-procedural use during electro-anatomic mapping (EAM) and interventional guidance in atrial fibrillation (AF) ablation procedures. In this paper, we present a novel technique to intra-procedural surface generation which integrates fully-automated segmentation of the LAPVs for guidance in AF ablation interventions. Contrast-enhanced rotational X-ray angiography (3-D RA) acquisitions in combination with filtered-back-projection-based reconstruction allows for volumetric interrogation of LAPV anatomy in near-real-time. An automatic model-based segmentation algorithm allows for fast and accurate LAPV mesh generation despite the challenges posed by image quality; relative to pre-procedural cardiac CT/MR, 3-D RA images suffer from more artifacts and reduced signal-to-noise. We validate our integrated method by comparing 1) automatic and manual segmentations of intra-procedural 3-D RA data, 2) automatic segmentations of intra-procedural 3-D RA and pre-procedural CT/MR data, and 3) intra-procedural EAM point cloud data with automatic segmentations of 3-D RA and CT/MR data. Our validation results for automatically segmented intra-procedural 3-D RA data show average segmentation errors of 1) approximately 1.3 mm compared with manual 3-D RA segmentations 2) approximately 2.3 mm compared with automatic segmentation of pre-procedural CT/MR data and 3

Near-optimum procedure for half-life measurement by high-resolution gamma-ray spectrometry

International Nuclear Information System (INIS)

Parker, J.L.

1989-01-01

A near-optimum procedure for using high-resolution γ-ray spectrometry to measure the half-lives of appropriate γ-ray- emitting-nuclides is presented. Among the important points of the procedure are the employment of the reference source method for implicit correction of pileup and deadtime losses; the use of full-energy peak-area ratios as the fundamental measured quantities; and continuous, high-rate data acquisition to obtain good results in a fraction of a half-life if desired. Equations are given for estimating the precision of the computed half-lives in terms of total measurement time, number of spectral acquisitions, and the precision of peak-area ratios. Results of 169 Yb half-life measurements are given as an example of the procedure's application. 3 refs., 2 tabs

A fast and efficient adaptive parallel ray tracing based model for thermally coupled surface radiation in casting and heat treatment processes

International Nuclear Information System (INIS)

Fainberg, J; Schaefer, W

2015-01-01

A new algorithm for heat exchange between thermally coupled diffusely radiating interfaces is presented, which can be applied for closed and half open transparent radiating cavities. Interfaces between opaque and transparent materials are automatically detected and subdivided into elementary radiation surfaces named tiles. Contrary to the classical view factor method, the fixed unit sphere area subdivision oriented along the normal tile direction is projected onto the surrounding radiation mesh and not vice versa. Then, the total incident radiating flux of the receiver is approximated as a direct sum of radiation intensities of representative “senders” with the same weight factor. A hierarchical scheme for the space angle subdivision is selected in order to minimize the total memory and the computational demands during thermal calculations. Direct visibility is tested by means of a voxel-based ray tracing method accelerated by means of the anisotropic Chebyshev distance method, which reuses the computational grid as a Chebyshev one. The ray tracing algorithm is fully parallelized using MPI and takes advantage of the balanced distribution of all available tiles among all CPU's. This approach allows tracing of each particular ray without any communication. The algorithm has been implemented in a commercial casting process simulation software. The accuracy and computational performance of the new radiation model for heat treatment, investment and ingot casting applications is illustrated using industrial examples. (paper)

Interfering line in trace analysis by X-ray spectrometry: Radiative auger satellites

International Nuclear Information System (INIS)

Maeda, Kuniko; Kawai, Jun.

1994-01-01

Strong characteristic X-ray lines (e.g. Kα and Kβ) are accompanied by broad low-energy satellites caused by the radiative Auger effect (RAE). In order to prove how the RAE satellites interfere the analysis of minor elements, low-energy side spectra of Ca and Ti Kβ, and Ca-Fe Kα were measured. The obtained RAE intensities are summarized together with published experimental and theoretical data. The integrated intensities of satellites due to K → MM, K → LM and K → LL RAE relative to that of Kα are determined to be of the order of 0.01-0.1%. This warns that the neglecting of the RAE satellites will introduce a serious error in trace analysis. (author)

Distribution of trace levels of therapeutic gallium in bone as mapped by synchrotron X-ray microscopy

International Nuclear Information System (INIS)

Bockman, R.S.; Repo, M.A.; Warrell, R.P. Jr.; Pounds, J.G.; Schidlovsky, G.; Gordon, B.M.; Jones, K.W.

1990-01-01

Gallium nitrate, a drug that inhibits calcium release from bone, has been proven a safe and effective treatment for the accelerated bone resorption associated with cancer. Though bone is a target organ for gallium, the kinetics, sites, and effects of gallium accumulation in bone are not known. The authors have used synchrotron X-ray microscopy to map the distribution of trace levels of gallium in bone. After short-term in vivo administration of gallium nitrate to rats, trace (nanogram) amounts of gallium preferentially localized to the metabolically active regions in the metaphysis as well as the endosteal and periosteal surfaces of diaphyseal bone, regions where new bone formation and modeling were occurring. The amounts measured were well below the levels known to be cytotoxic. Iron and zinc, trace elements normally found in bone, were decreased in amount after in vivo administration of gallium. These studies represent a first step toward understanding the mechanism(s) of action of gallium in bone by suggesting the possible cellular, structural, and elemental targets of gallium

MC ray-tracing optimization of lobster-eye focusing devices with RESTRAX

International Nuclear Information System (INIS)

Saroun, Jan; Kulda, Jiri

2006-01-01

The enhanced functionalities of the latest version of the RESTRAX software, providing a high-speed Monte Carlo (MC) ray-tracing code to represent a virtual three-axis neutron spectrometer, include representation of parabolic and elliptic guide profiles and facilities for numerical optimization of parameter values, characterizing the instrument components. As examples, we present simulations of a doubly focusing monochromator in combination with cold neutron guides and lobster-eye supermirror devices, concentrating a monochromatic beam to small sample volumes. A Levenberg-Marquardt minimization algorithm is used to optimize simultaneously several parameters of the monochromator and lobster-eye guides. We compare the performance of optimized configurations in terms of monochromatic neutron flux and energy spread and demonstrate the effect of lobster-eye optics on beam transformations in real and momentum subspaces

Do Peripheral Refraction and Aberration Profiles Vary with the Type of Myopia? - An Illustration Using a Ray-Tracing Approach

Directory of Open Access Journals (Sweden)

Ravi C. Bakaraju

2009-01-01

Conclusion: This study has indicated that myopic eyes with primarily an axial component may have a greater risk of progression than their refractive counterparts albeit with the same degree of refractive error. This prediction emerges from the presented theoretical ray tracing model and, therefore, requires clinical confirmation.

SolTrace: A Ray-Tracing Code for Complex Solar Optical Systems

Energy Technology Data Exchange (ETDEWEB)

Wendelin, Tim [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lewandowski, Allan [Allan Lewandowski Solar Consulting LLC, Evergreen, CO (United States)

2013-10-01

SolTrace is an optical simulation tool designed to model optical systems used in concentrating solar power (CSP) applications. The code was first written in early 2003, but has seen significant modifications and changes since its inception, including conversion from a Pascal-based software development platform to C++. SolTrace is unique in that it can model virtually any optical system utilizingthe sun as the source. It has been made available for free and as such is in use worldwide by industry, universities, and research laboratories. The fundamental design of the code is discussed, including enhancements and improvements over the earlier version. Comparisons are made with other optical modeling tools, both non-commercial and commercial in nature. Finally, modeled results are shownfor some typical CSP systems and, in one case, compared to measured optical data.

A discrete spherical X-ray transform of orientation distribution functions using bounding cubes

DEFF Research Database (Denmark)

Kazantsev, Ivan G; Schmidt, Søren; Poulsen, Henning Friis

2009-01-01

We investigate a cubed sphere parametrization of orientation space with the aim of constructing a discrete voxelized version of the spherical x-ray transform. For tracing the propagation of a unit great circle through the partition subsets, the frustums of the cubed sphere, a fast procedure...

Trace element determination in tomato puree using particle induced X-ray emission and Rutherford backscattering

International Nuclear Information System (INIS)

Romero-Davila, E.; Miranda, J.

2004-01-01

Particle induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) were used to determine the concentrations of trace elements in samples of 12 tomato puree brands sold in the Mexican market. While RBS offered information about the main elements present in the matrix, PIXE gave results on trace elements. As a whole, data for 17 elements (C, N, O, Na, Mg, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn) were obtained. To evaluate the results, a comparison with brands from USA, Japan, Colombia, and Chile was carried out, using tomato purees produced following the domestic technology recipe. Additionally, the results were considered in the light of the Codex Alimentarius and the Mexican standard. It was found that all of the brands fall within the limits established by these standards, being of the same order of magnitude as the foreign brands. (author)

Trace elements in natural azurite pigments found in illuminated manuscript leaves investigated by synchrotron x-ray fluorescence and diffraction mapping

Science.gov (United States)

Smieska, Louisa M.; Mullett, Ruth; Ferri, Laurent; Woll, Arthur R.

2017-07-01

We present trace-element and composition analysis of azurite pigments in six illuminated manuscript leaves, dating from the thirteenth to sixteenth century, using synchrotron-based, large-area x-ray fluorescence (SR-XRF) and diffraction (SR-XRD) mapping. SR-XRF mapping reveals several trace elements correlated with azurite, including arsenic, zirconium, antimony, barium, and bismuth, that appear in multiple manuscripts but were not always detected by point XRF. Within some manuscript leaves, variations in the concentration of trace elements associated with azurite coincide with distinct regions of the illuminations, suggesting systematic differences in azurite preparation or purification. Variations of the trace element concentrations in azurite are greater among different manuscript leaves than the variations within each individual leaf, suggesting the possibility that such impurities reflect distinct mineralogical/geologic sources. SR-XRD maps collected simultaneously with the SR-XRF maps confirm the identification of azurite regions and are consistent with impurities found in natural mineral sources of azurite. In general, our results suggest the feasibility of using azurite trace element analysis for provenance studies of illuminated manuscript fragments, and demonstrate the value of XRF mapping in non-destructive determination of trace element concentrations within a single pigment.

Trace elements in natural azurite pigments found in illuminated manuscript leaves investigated by synchrotron x-ray fluorescence and diffraction mapping

Energy Technology Data Exchange (ETDEWEB)

Smieska, Louisa M.; Woll, Arthur R. [Cornell High Energy Synchrotron Source, Wilson Laboratory, Ithaca, NY (United States); Mullett, Ruth [Cornell University, Medieval Studies Program, Ithaca, NY (United States); Ferri, Laurent [Cornell University, Cornell Library Rare and Manuscript Collections, Ithaca, NY (United States)

2017-07-15

We present trace-element and composition analysis of azurite pigments in six illuminated manuscript leaves, dating from the thirteenth to sixteenth century, using synchrotron-based, large-area x-ray fluorescence (SR-XRF) and diffraction (SR-XRD) mapping. SR-XRF mapping reveals several trace elements correlated with azurite, including arsenic, zirconium, antimony, barium, and bismuth, that appear in multiple manuscripts but were not always detected by point XRF. Within some manuscript leaves, variations in the concentration of trace elements associated with azurite coincide with distinct regions of the illuminations, suggesting systematic differences in azurite preparation or purification. Variations of the trace element concentrations in azurite are greater among different manuscript leaves than the variations within each individual leaf, suggesting the possibility that such impurities reflect distinct mineralogical/geologic sources. SR-XRD maps collected simultaneously with the SR-XRF maps confirm the identification of azurite regions and are consistent with impurities found in natural mineral sources of azurite. In general, our results suggest the feasibility of using azurite trace element analysis for provenance studies of illuminated manuscript fragments, and demonstrate the value of XRF mapping in non-destructive determination of trace element concentrations within a single pigment. (orig.)

Metrology of variable-line-spacing x-ray gratings using the APS Long Trace Profiler

Science.gov (United States)

Sheung, Janet; Qian, Jun; Sullivan, Joseph; Thomasset, Muriel; Manton, Jonathan; Bean, Sunil; Takacs, Peter; Dvorak, Joseph; Assoufid, Lahsen

2017-09-01

As resolving power targets have increased with each generation of beamlines commissioned in synchrotron radiation facilities worldwide, diffraction gratings are quickly becoming crucial optical components for meeting performance targets. However, the metrology of variable-line-spacing (VLS) gratings for high resolution beamlines is not widespread; in particular, no metrology facility at any US DOE facility is currently equipped to fully characterize such gratings. To begin to address this issue, the Optics Group at the Advanced Photon Source at Argonne, in collaboration with SOLEIL and with support from Brookhaven National Laboratory (BNL), has developed an alternative beam path addition to the Long Trace Profiler (LTP) at Argonne's Advanced Photon Source. This significantly expands the functionality of the LTP not only to measure mirrors surface slope profile at normal incidence, but also to characterize the groove density of VLS diffraction gratings in the Littrow incidence up to 79°, which covers virtually all diffraction gratings used at synchrotrons in the first order. The LTP light source is a 20mW HeNe laser, which yields enough signal for diffraction measurements to be performed on low angle blazed gratings optimized for soft X-ray wavelengths. We will present the design of the beam path, technical requirements for the optomechanics, and our data analysis procedure. Finally, we discuss challenges still to be overcome and potential limitations with use of the LTP to perform metrology on diffraction gratings.

Genetic risk from diagnostic X-ray procedures

International Nuclear Information System (INIS)

Stephan, G.

1980-01-01

This essay introduces epidemiologic studies concerned with the question whether diagnostic X-ray procedures might be the cause of an increased genetic risk. All studies have selected Down's syndrome (mongolism) as genetic indicator. They indiscriminately present the opinion of the respective author. Approximately one half of the studies conclude that radiation exposure will not influence the spontaneous incidence of Down's syndrome in diagnostics, the other half finds a positive relationship between frequent radiation exposure and the incidence of the syndrome. For various reasons, explained in detail, the results of the studies under discussion are suitable for forming hypotheses, but should not be viewed as providing evidence. (orig.) [de

The determination of the C, N, O and trace element content of Triticum aestivum by activation analysis, X-ray excitation and mass spectrometry

International Nuclear Information System (INIS)

Leonhardt, J.W.; Dahn, E.; Dietze, H.J.; Freyer, K.; Geisler, M.; Hartmann, G.; Jung, K.; Schelhorn, H.

1979-01-01

The results of determinations of the C, N, O and trace element content of grains, sprouts and leaves of Triticum aestivum by means of various methods of activation analysis, X-ray excitation and mass spectrometry are presented. The C and O contents were determined by X-ray excitation; the O, N, P and Si contents were measured by NAA with 14-MeV neutrons, and the trace elements were determined by NAA with thermal neutrons. A mass-spectrometric survey analysis confirmed the results obtained by NAA. The use of neutron-induced nuclear reactions together with autoradiography enabled a representative picture to be formed of the spatial distribution in two dimensions of 14 N in biological specimens. (author)

Patient-specific scatter correction in clinical cone beam computed tomography imaging made possible by the combination of Monte Carlo simulations and a ray tracing algorithm

International Nuclear Information System (INIS)

Thing, Rune S.; Bernchou, Uffe; Brink, Carsten; Mainegra-Hing, Ernesto

2013-01-01

Purpose: Cone beam computed tomography (CBCT) image quality is limited by scattered photons. Monte Carlo (MC) simulations provide the ability of predicting the patient-specific scatter contamination in clinical CBCT imaging. Lengthy simulations prevent MC-based scatter correction from being fully implemented in a clinical setting. This study investigates the combination of using fast MC simulations to predict scatter distributions with a ray tracing algorithm to allow calibration between simulated and clinical CBCT images. Material and methods: An EGSnrc-based user code (egs c bct), was used to perform MC simulations of an Elekta XVI CBCT imaging system. A 60keV x-ray source was used, and air kerma scored at the detector plane. Several variance reduction techniques (VRTs) were used to increase the scatter calculation efficiency. Three patient phantoms based on CT scans were simulated, namely a brain, a thorax and a pelvis scan. A ray tracing algorithm was used to calculate the detector signal due to primary photons. A total of 288 projections were simulated, one for each thread on the computer cluster used for the investigation. Results: Scatter distributions for the brain, thorax and pelvis scan were simulated within 2 % statistical uncertainty in two hours per scan. Within the same time, the ray tracing algorithm provided the primary signal for each of the projections. Thus, all the data needed for MC-based scatter correction in clinical CBCT imaging was obtained within two hours per patient, using a full simulation of the clinical CBCT geometry. Conclusions: This study shows that use of MC-based scatter corrections in CBCT imaging has a great potential to improve CBCT image quality. By use of powerful VRTs to predict scatter distributions and a ray tracing algorithm to calculate the primary signal, it is possible to obtain the necessary data for patient specific MC scatter correction within two hours per patient

Dibenzylammonium and sodium dibenzyldithiocarbamates as precipitants for preconcentration of trace elements in water for analysis by energy dispersive X-ray fluorescence

International Nuclear Information System (INIS)

Moore, R.V.

1982-01-01

Precipitation with combined dibenzylammonium dibenzyldithiocarbamate and sodium dibenzyldithiocarbamate at pH 5.0 can be used to separate 22 trace elements from water. Membrane filtration of the precipitate yielded a thin sample, suitable for analysis by energy dispersive X-ray fluorescence spectrometry. Alkalis, alkaline earths, lanthanides, and halides were not precipitated, permitting a clean separation of trace elements from the macro constituents of drinking water and drinking water supplies. Methods are given for preparation of reagents of higher purity than previously described

Applications of X-ray emission to elemental analysis of foods

International Nuclear Information System (INIS)

Flocchini, R.G.; Lagunas-Solar, M.C.; Perley, B.P.

1996-01-01

Trace element analysis via X-Ray Fluorescence (XRF) and Proton-Induced X-Ray Emission (PIXE) techniques were applied to several samples of fresh and processed foods. Thin samples of fresh fruits and vegetables, processed dry foods, and spices were included in these analyses. The results indicate that XRF and/or PIXE analysis is applicable to these types of samples but require special and simple modifications in sample preparation techniques, and the inclusion of new matrix type corrections for data analysis. However, the non-destructive nature, reproducibility, efficiency and high sensitivity that characterize these multi-element analytical procedures can provide new potential methods for detecting trace elements in foods and in many agricultural commodities. Toxic metals such as Hg, Pb, and As were detected in some foods. In addition, other essential or neutral trace elements such as Na, K, Mg, Ca, Cu, Cr, V, Zn, Mo, Fe, Mn, Ni, Se, Cl, S, and P were also detected. These and other elements can be analyzed rapidly and with high sensitivity for applications in process control and for certification of food quality. Developing these techniques and procedures specifically for food and for various agricultural products may provide new analytical options and help mitigate the expected impact of forthcoming regulations intended to establish limits and tolerance levels for micro toxicants and other essential nutrients in foods and agricultural products. (author)

Simulating an extreme over-the-horizon optical propagation event over Lake Michigan using a coupled mesoscale modeling and ray tracing framework

NARCIS (Netherlands)

Basu, S.

2017-01-01

Accurate simulation and forecasting of over-the-horizon propagation events are essential for various civilian and defense applications. We demonstrate the prowess of a newly proposed coupled mesoscale modeling and ray tracing framework in reproducing such an event. Wherever possible, routinely

The dopamine D1 receptor agonist SKF81297 has dose-related effects on locomotor activity but is without effect in a CER trace conditioning procedure conducted with two versus four trials.

Science.gov (United States)

Pezze, M A; Marshall, H J; Cassaday, H J

2016-08-01

In an appetitively motivated procedure, we have previously reported that systemic treatment with the dopamine (DA) D1 receptor agonist SKF81297 (0.4 and 0.8 mg/kg) depressed acquisition at a 2 s inter-stimulus-interval (ISI), suitable to detect trace conditioning impairment. However since DA is involved in reinforcement processes, the generality of effects across appetitively- and aversively-motivated trace conditioning procedures cannot be assumed. The present study tested the effects of SKF81297 (0.4 and 0.8 mg/kg) in an established conditioned emotional response (CER) procedure. Trace-dependent conditioning was clearly shown in two experiments: while conditioning was relatively strong at a 3-s ISI, it was attenuated at a 30-s ISI. This was shown after two (Experiment 1) or four (Experiment 2) conditioning trials conducted in - as far as possible - the same CER procedure. Contrary to prediction, in neither experiment was there any indication that trace conditioning was attenuated by treatment with 0.4 or 0.8 mg/kg SKF81297. In the same rats, locomotor activity was significantly enhanced at the 0.8 mg/kg dose of SKF81297. These results suggest that procedural details of the trace conditioning variant in use are an important determinant of the profile of dopaminergic modulation.

Fast procedures for coincidence-summing correction in γ-ray spectrometry

International Nuclear Information System (INIS)

De Felice, Pierino; Angelini, Paola; Fazio, Aldo; Biagini, Roberto

2000-01-01

Simplified and fast procedures for coincidence-summing correction in γ-ray spectrometry were investigated. These procedures are based on the usual theoretical expressions of the correction factors, but differ in the determination of the total efficiency curve based on the following approximations: (a) replacement, below the knee efficiency value, of the total efficiency by the full-energy peak efficiency; and (b) use of linear interpolations (in log-log plot) between only two experimental points above the knee efficiency value; or (c) assumption of a peak-to-total efficiency ratio independent on the counting geometry; or (d) assumption of a constant relation between the peak-to-total efficiency ratios and the photoelectric-to-total cross section ratios. The above approximations were separately assumed for determination of the coincidence-summing correction factors for nuclides with complex decay scheme ( 133 Ba, 134 Cs, 152 Eu) and for 60 Co and 88 Y measured on a 15% relative efficiency p-type coaxial HPGe detector, for three source-detector geometries: point source placed on top of and at 10 cm from the detector window, and 1 l Marinelli beaker filled with aqueous solution. The results were compared with those based on more accurate experimental determinations of the total efficiency curve from measurements of standard sources of eight different single-γ-ray emitters. The usefulness of each simplified procedure is evaluated with respect to its accuracy and to the reduction of the number of standard sources and measurement time

TRACING THE LOWEST PROPELLER LINE IN MAGELLANIC HIGH-MASS X-RAY BINARIES

Energy Technology Data Exchange (ETDEWEB)

Christodoulou, Dimitris M.; Laycock, Silas G. T.; Yang, Jun; Fingerman, Samuel, E-mail: dimitris_christodoulou@uml.edu, E-mail: silas_laycock@uml.edu, E-mail: jun_yang@uml.edu, E-mail: fingerman.samuel@gmail.com [Lowell Center for Space Science and Technology, 600 Suffolk Street, Lowell, MA 01854 (United States)

2016-09-20

We have combined the published observations of high-mass X-ray binary (HMXB) pulsars in the Magellanic Clouds with a new processing of the complete archival data sets from the XMM-Newton and Chandra observatories in an attempt to trace the lowest propeller line below which accretion to polar caps is inhibited by the centrifugal force and the pulsations from the most weakly magnetized pulsars cease. Previously published data reveal that some of the faster-spinning pulsars with spin periods of P {sub S} < 12 s, detected at relatively low X-ray luminosities L {sub X} , appear to define such a line in the P {sub S} – L {sub X} diagram, characterized by a magnetic moment of μ = 3 × 10{sup 29} G cm{sup 3}. This value implies the presence of surface magnetic fields of B ≥ 3 × 10{sup 11} G in the compact objects of this class. Only a few quiescent HMXBs are found below the propeller line: LXP4.40 and SXP4.78, for which XMM-Newton and Chandra null detections respectively placed firm upper limits on their X-ray fluxes in deep quiescence; and A0538-66, for which many sub-Eddington detections have never measured any pulsations. On the other hand, the data from the XMM-Newton and Chandra archives show clearly that, during routine observation cycles, several sources have been detected below the propeller line in extremely faint, nonpulsating states that can be understood as the result of weak magnetospheric emission when accretion to the poles is centrifugally stalled or severely diminished. We also pay attention to the anomalous X-ray pulsar CXOU J010043.1-721134 that was reported in HMXB surveys. Its pulsations and locations near and above the propeller line indicate that this pulsar could be accreting from a fossil disk.

Ray Tracing for Ocean Acoustic Tomography

National Research Council Canada - National Science Library

Dushaw, Brian

1998-01-01

.... The Numerical Recipes software package provided the basis for much of this computer code. The ray equations are reviewed, and ray equations that include the effects of ocean current are derived...

A low power x-ray tube for use in energy dispersive x-ray fluorescence analysis

International Nuclear Information System (INIS)

Kataria, S.K.; Govil, Rekha; Lal, M.

1980-01-01

A low power X-ray tube with thin molybdenum transmission target for use in energy dispersive X-ray fluorescence (ENDXRF) element analysis has been indigenously built, along with its power supply. The X-ray tube has been in operation since August 1979, and it has been operated upto maximum target voltage of 35 KV and tube current upto 200 μA which is more than sufficient for trace element analysis. This X-ray tube has been used alongwith the indigenously built Si(Li) detector X-ray spectrometer with an energy resolution of 200 eV at 5.9 Kev MnKsub(α) X-ray peak for ENDXRF analysis. A simple procedure of calibration has been developed for thin samples based on the cellulose diluted, thin multielement standard pellets. Analytical sensitivities of the order of a few p.p.m. have been obtained with the experimental setup for elements with 20 < = Z < = 38 and 60 < = Z < = 90. A number of X-ray spectra for samples of environmental, biological, agricultural, industrial and metallurgical interest are presented to demonstrate the salient features of the experimental sep up. (auth.)

Diagnostic x-ray equipment compliance and facility survey. Recommended procedures for equipment and facility testing

International Nuclear Information System (INIS)

1994-01-01

The Radiation Protection Bureau has set out guidelines for the testing of diagnostic x-ray equipment and facilities. This guide provides information for the x-ray inspector, test engineer, technologist, medical physicist and any other person responsible for verifying the regulatory compliance or safety of diagnostic x-ray equipment and facilities. Diagnostic x-radiation is an essential part of present day medical practice. The largest contributor of irradiation to the general population comes from diagnostic x-radiation. Although individual irradiations are usually small, there is a concern of possible excess cancer risk when large populations are irradiated. Unnecessary irradiations to patients from radiological procedures can be significantly reduced with little or no decrease in the value of medical diagnostic information. This can be achieved by using well designed x-ray equipment which is installed, used and maintained by trained personnel, and by the adoption of standardized procedures. In general, when patient surface dose is reduced, there is a corresponding decrease in dose to x-ray equipment operators and other health care personnel. 2 tabs., 4 figs

Diagnostic x-ray equipment compliance and facility survey. Recommended procedures for equipment and facility testing

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

The Radiation Protection Bureau has set out guidelines for the testing of diagnostic x-ray equipment and facilities. This guide provides information for the x-ray inspector, test engineer, technologist, medical physicist and any other person responsible for verifying the regulatory compliance or safety of diagnostic x-ray equipment and facilities. Diagnostic x-radiation is an essential part of present day medical practice. The largest contributor of irradiation to the general population comes from diagnostic x-radiation. Although individual irradiations are usually small, there is a concern of possible excess cancer risk when large populations are irradiated. Unnecessary irradiations to patients from radiological procedures can be significantly reduced with little or no decrease in the value of medical diagnostic information. This can be achieved by using well designed x-ray equipment which is installed, used and maintained by trained personnel, and by the adoption of standardized procedures. In general, when patient surface dose is reduced, there is a corresponding decrease in dose to x-ray equipment operators and other health care personnel. 2 tabs., 4 figs.

Dose distribution in head and neck during dental x-ray procedures

International Nuclear Information System (INIS)

Mason, E.W.; Goepp, R.A.

1978-01-01

Previous studies, notably by Franklin (Angle Ortho., 43:53-64, 1973), have shown significant exposures during cephalometric dental procedures and ways in which these exposures can be reduced. Skin dose over thyroid tissue has been measured by Alcox (J. Am. Dent. Assoc., 88:568-579, 1974), and others. This study is an expansion of thyroid dose measurements by Block, Goepp, and Mason (Angle Ortho., 47:17-24, 1977). The internal dose distribution in the head and neck area due to cephalometric and panoramic dental x-ray procedures is shown along with the dependence of orbit and thyroid dose on patient positioning. Higher doses can be delivered to deep tissue by panoramic machines since tissue at the axis of rotation is exposed during the entire procedure. (author)

Advanced 3D tools used in reverse engineering and ray tracing simulation of phased array inspection of turbine components with complex geometry

International Nuclear Information System (INIS)

Daks, W.; Kovacshazy, C.; Mair, D.; Ciorau, P.

2002-01-01

This paper outlines the practical aspects of reverse engineering and the integration of multiple pieces of software (Drafting, CNC Machining, Ray Tracing, Inspection Simulation Scenario and Phased Array UT Analysis), in order to inspect turbine components comprised of complex geometry. The CNC software, Mastercam, and design software, CADKEY/FastSURF, were used to validate the phased-array automated and manual inspection of blade root, rotor steeples and disk-blade rim attachment. The integration of a 3D part in the software engine, Imagine 3D and SimScan, as well as Tomoview analysis (specimen feature) is based on CADKEY Developer Kit - IGES/SAT file format. A generic Ray Tracing simulation for multi-probe beam was integrated into Imagine 3D. Representative examples of reference blocks and mock-ups, UT simulation and phased-array data comparison are presented. (author)

Ray Tracing Results for Elevation Angle Spread of Departure and its Impact on System Performance

DEFF Research Database (Denmark)

Mondal, Bishwarup; Thomas, Timothy; Nguyen, Huan Cong

2014-01-01

Elevation spread of departure angles (ESD) is the key parameter characterizing a 3D fast-fading channel model. 3D channel mod-eling is currently being studied in 3GPP to enable the develop-ment of MIMO techniques exploiting both azimuth and elevation dimensions of the channel. In this paper we use...... ray-tracing techniques to estimate the ESD behavior in Manhattan and Copenhagen city environments and compare it with the 3GPP ESD model. We also investigate the ESD spread within a cluster of rays and show that the ESD within a cluster depends significantly on the distance of the mobile from the base......-station. This char-acterization addresses a gap in the existing literature. Simulation results show that the performance of MIMO techniques such as vertical sectorization depends significantly on the ESD of the underlying environment. This observation also underscores the importance of an accurate ESD model....

Simulation of Satellite, Airborne and Terrestrial LiDAR with DART (I):Waveform Simulation with Quasi-Monte Carlo Ray Tracing

Science.gov (United States)

Gastellu-Etchegorry, Jean-Philippe; Yin, Tiangang; Lauret, Nicolas; Grau, Eloi; Rubio, Jeremy; Cook, Bruce D.; Morton, Douglas C.; Sun, Guoqing

2016-01-01

Light Detection And Ranging (LiDAR) provides unique data on the 3-D structure of atmosphere constituents and the Earth's surface. Simulating LiDAR returns for different laser technologies and Earth scenes is fundamental for evaluating and interpreting signal and noise in LiDAR data. Different types of models are capable of simulating LiDAR waveforms of Earth surfaces. Semi-empirical and geometric models can be imprecise because they rely on simplified simulations of Earth surfaces and light interaction mechanisms. On the other hand, Monte Carlo ray tracing (MCRT) models are potentially accurate but require long computational time. Here, we present a new LiDAR waveform simulation tool that is based on the introduction of a quasi-Monte Carlo ray tracing approach in the Discrete Anisotropic Radiative Transfer (DART) model. Two new approaches, the so-called "box method" and "Ray Carlo method", are implemented to provide robust and accurate simulations of LiDAR waveforms for any landscape, atmosphere and LiDAR sensor configuration (view direction, footprint size, pulse characteristics, etc.). The box method accelerates the selection of the scattering direction of a photon in the presence of scatterers with non-invertible phase function. The Ray Carlo method brings traditional ray-tracking into MCRT simulation, which makes computational time independent of LiDAR field of view (FOV) and reception solid angle. Both methods are fast enough for simulating multi-pulse acquisition. Sensitivity studies with various landscapes and atmosphere constituents are presented, and the simulated LiDAR signals compare favorably with their associated reflectance images and Laser Vegetation Imaging Sensor (LVIS) waveforms. The LiDAR module is fully integrated into DART, enabling more detailed simulations of LiDAR sensitivity to specific scene elements (e.g., atmospheric aerosols, leaf area, branches, or topography) and sensor configuration for airborne or satellite LiDAR sensors.

X-ray exposure hazards for physicians performing ablation procedures and device implantation

DEFF Research Database (Denmark)

Marinskis, Germanas; Bongiorni, Maria Grazia; Dagres, Nikolaos

2013-01-01

The purpose of the survey was to evaluate physician's and authorities policies and clinical practices when using occupational X-ray during ablation procedures and device implantation. This survey shows infrequent use of lead gloves, radiation absorbing pads, and lead glass cabins, but increasing ...

Trace analysis of semiconductor materials

CERN Document Server

Cali, J Paul; Gordon, L

1964-01-01

Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

A comparison of partially specular radiosity and ray tracing for room acoustics modeling

Science.gov (United States)

Beamer, C. Walter; Muehleisen, Ralph T.

2005-04-01

Partially specular (PS) radiosity is an extended form of the general radiosity method. Acoustic radiosity is a form of bulk transfer of radiant acoustic energy. This bulk transfer is accomplished through a system of energy balance equations that relate the bulk energy transfer of each surface in the system to all other surfaces in the system. Until now acoustic radiosity has been limited to modeling only diffuse surface reflection. The new PS acoustic radiosity method can model all real surface types, diffuse, specular and everything in between. PS acoustic radiosity also models all real source types and distributions, not just point sources. The results of the PS acoustic radiosity method are compared to those of well known ray tracing programs. [Work supported by NSF.

Simultaneous Determination of 30 Trace Elements in Cancerous and Noncancerous Human Tissue Samples with Gamma-ray Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K; Brune, D; Wester, P O

1963-10-15

The following trace elements were quantitatively determined by gamma-ray spectrometry in T samples of non-cancerous and 5 samples of cancerous human tissue: P, Ca, Cr, Fe, Co, Cu, Zn, As, Se, Br, Rb, Mo, Ag, Cd, Sb, Cs, La, Au, and Hg. In some of the samples the following elements were qualitatively determined: Ti+Sc, Ga, Sr, In, Ba, Ce, Hf, Os, Pt, and U. Most of the trace elements were found to be present in much higher concentrations in the non-cancerous than in the corresponding cancerous liver samples. In a typical run one sample each of cancerous and non-cancerous tissue was irradiated together with standards of the elements to be determined in a thermal flux of 2.10{sup 13} n/cm{sup 2}/sec. for 24 hours. The radioactive trace elements were separated into 16, and in some cases 18, groups by means of a chemical group separation method. Subsequently, the gamma spectrometric measurements were performed. Two persons can manage the chemical separations and measure the different activities from a run in 1,5 days. A new method of comparing unknown samples with standards was developed.

Rapid Chemometric X-Ray Fluorescence approaches for spectral Diagnostics of Cancer utilizing Tissue Trace Metals and Speciation profiles

International Nuclear Information System (INIS)

Okonda, J.J.

2015-01-01

Energy dispersive X-ray fluorescence (EDXRF) spectroscopy is an analytical method for identification and quantification of elements in materials by measurement of their spectral energy and intensity. EDXRFS spectroscopic technique involves simultaneous non-invasive acquisition of both fluorescence and scatter spectra from samples for quantitative determination of trace elemental content in complex matrix materials. The objective is develop a chemometric-aided EDXRFS method for rapid diagnosis of cancer and its severity (staging) based on analysis of trace elements (Cu, Zn, Fe, Se and Mn), their speciation and multivariate alterations of the elements in cancerous body tissue samples as cancer biomarkers. The quest for early diagnosis of cancer is based on the fact that early intervention translates to higher survival rate and better quality of life. Chemometric aided EDXRFS cancer diagnostic model has been evaluated as a direct and rapid superior alternative for the traditional quantitative methods used in XRF such as FP method. PCA results of cultured samples indicate that it is possible to characterize cancer at early and late stage of development based on trace elemental profiles

Sample preparation techniques in trace element analysis by X-ray emission spectroscopy

International Nuclear Information System (INIS)

Valkovic, V.

1983-11-01

The report, written under a research contract with the IAEA, contains a detailed presentation of the most difficult problem encountered in the trace element analysis by methods of the X-ray emission spectroscopy, namely the sample preparation techniques. The following items are covered. Sampling - with specific consideration of aerosols, water, soil, biological materials, petroleum and its products, storage of samples and their handling. Pretreatment of samples - preconcentration, ashing, solvent extraction, ion exchange and electrodeposition. Sample preparations for PIXE - analysis - backings, target uniformity and homogeneity, effects of irradiation, internal standards and specific examples of preparation (aqueous, biological, blood serum and solid samples). Sample preparations for radioactive sources or tube excitation - with specific examples (water, liquid and solid samples, soil, geological, plants and tissue samples). Finally, the problem of standards and reference materials, as well as that of interlaboratory comparisons, is discussed

Developments in the ray-tracing code Zgoubi for 6-D multiturn tracking in FFAG rings

International Nuclear Information System (INIS)

Lemuet, F.; Meot, F.

2005-01-01

A geometrical method for 3-D modeling of the magnetic field in scaling and non-scaling FFAG magnets has been installed in the ray-tracing code Zgoubi. The method in particular allows a good simulation of transverse non-linearities, of field fall-offs and possible merging fields in configurations of neighboring magnets, while using realistic models of magnetic fields. That yields an efficient tool for FFAG lattice design and optimizations, and for 6-D tracking studies. It is applied for illustration to the simulation of an acceleration cycle in a 150 MeV radial sector proton FFAG

Determination of trace amounts of metals in saline water by energy-dispersive XRF (with the Na-DDTC preconcentration)

International Nuclear Information System (INIS)

Holynska, B.; Bisiniek, K.

1975-01-01

A simple method for the determination of trace concentrations of metals in saline water is described. The analytical procedure involves the separation of metal ions of Cu(2), Zn(2), Hg(2) and Fe(3) by precipitation with diethyldithiocarbamate (DDTC). The radioisotope X-ray fluorescence method using Si/Li detector has been applied for the determination of metal ions closed in the DDTC deposition. (author)

Sampling, storage and sample preparation procedures for X ray fluorescence analysis of environmental materials

International Nuclear Information System (INIS)

1997-06-01

X ray fluorescence (XRF) method is one of the most commonly used nuclear analytical technique because of its multielement and non-destructive character, speed, economy and ease of operation. From the point of view of quality assurance practices, sampling and sample preparation procedures are the most crucial steps in all analytical techniques, (including X ray fluorescence) applied for the analysis of heterogeneous materials. This technical document covers recent modes of the X ray fluorescence method and recent developments in sample preparation techniques for the analysis of environmental materials. Refs, figs, tabs

Laboratory manual on sample preparation procedures for x-ray micro-analysis

International Nuclear Information System (INIS)

1997-01-01

X-ray micro fluorescence is a non-destructive and sensitive method for studying the microscopic distribution of different elements in almost all kinds of samples. Since the beginning of this century, x-rays and electrons have been used for the analysis of many different kinds of material. Techniques which rely on electrons are mainly developed for microscopic studies, and are used in conventional Electron Microscopy (EM) or Scanning Electron Microscopy (SEM), while x-rays are widely used for chemical analysis at the microscopic level. The first chemical analysis by fluorescence spectroscopy using small x-ray beams was conducted in 1928 by Glockner and Schreiber. Since then much work has been devoted to developing different types of optical systems for focusing an x-ray beam, but the efficiency of these systems is still inferior to the conventional electron optical systems. However, even with a poor optical efficiency, the x-ray microbeam has many advantages compared with electron or proton induced x-ray emission methods. These include: The analyses are non-destructive, losses of mass are negligible, and due to the low thermal loading of x-rays, materials which may be thermally degraded can be analysed; Samples can be analysed in air, and no vacuum is required, therefore specimens with volatile components such as water in biological samples, can be imaged at normal pressure and temperature; No charging occurs during analysis and therefore coating of the sample with a conductive layer is not necessary; With these advantages, simpler sample preparation procedures including mounting and preservation can be used

Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

Directory of Open Access Journals (Sweden)

F. Saez de Adana

2009-01-01

Full Text Available This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD for the analysis of Ultra-Wideband (UWB mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

Trends and the determination of effective doses for standard X-ray procedures

International Nuclear Information System (INIS)

Johnson, H.M.; Neduzak, C.; Gallet, J.; Sandeman, J.

2001-01-01

Trends in the entrance skin exposures (air kerma) for standard x-ray imaging procedures are reported for the Province of Manitoba, Canada. Average annual data per procedure using standard phantoms and standard ion chambers have been recorded since 1981. For example, chest air kerma (backscatter included) has decreased from 0.14 to 0.09 mGy. Confounding factors may negate the gains unless facility quality control programs are maintained. The data were obtained for a quality assurance and regulatory compliance program. Quoting such data for risk evaluation purposes lacks rigor hence a compartment model for organ apportioning, using organ absorbed doses and weighting factors, has been applied to determine effective dose per procedure. The effective doses for the standard procedures are presented, including the value of 0.027 mSv (1999) calculated for the effective dose in PA chest imaging. (author)

XRF determination of trace and major elements using a single-fused disc

International Nuclear Information System (INIS)

Thomas, I.R.; Haukka, M.T.

1978-01-01

A new fusion method using lithium metaborate, suitable for the determination of major and trace elements by X-ray fluorescence analysis (XRF), has proven to be of comparable accuracy to other XRF methods for the ten major rock-forming oxides. The very low dilution allows determination of trace elements with a decrease in sensitivity of about a factor of 2 compared with XRF determination using pressed-powder pellets. A feature of the method is the flexibility of sample preparation allowed: the matrix-correction parameters may be used for a wide range of dilutions (sample/flux ratios), no 'Loss' correction is necessary, and imperfect or inhomogeneous discs may be crushed and pressed pellets made of the glass powder when required. Considerable savings in the time during preparation, analysis and correction of results are possible with current automation because of streamlining procedures

Determination of arsenic and other trace elements in cosmetics by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Gonzalez Cepeda, A.M.; Cienfuegos Silva, E.E.

1978-01-01

A general survey of trace-elements in different types of cosmetics, in particular arsenic, was carried out in order to detect elements that might be detrimental to human health. The samples were analyzed by instrumental neutron activation analysis and high-resolution gamma-ray spectrometry with Ge(Li) detectors. Different amounts of Br and Sb, detected in almost all the samples, produced interferencies in the determination of As when the 559 KeV photopeak was used. Since the triplet formed could not be resolved by the Ge(Li) detector, a mathematical procedure was developed using the 776 KeV gamma-ray emission of 82-Br and various factors found experimentally. This procedure was checked using laboratory-made samples of known concentrations and the results obtained had good precision and accuracy. In addition to arsenic the elements Co, Cr, Br, Sc, Fe and Zn were also quantitatively determined. Those cosmetics made from inorganic raw materials have an As concentration higher than those elaborated from organic materials. (EC)

Development and testing of a new ray-tracing approach to GNSS carrier-phase multipath modelling

Science.gov (United States)

Lau, Lawrence; Cross, Paul

2007-11-01

Multipath is one of the most important error sources in Global Navigation Satellite System (GNSS) carrier-phase-based precise relative positioning. Its theoretical maximum is a quarter of the carrier wavelength (about 4.8 cm for the Global Positioning System (GPS) L1 carrier) and, although it rarely reaches this size, it must clearly be mitigated if millimetre-accuracy positioning is to be achieved. In most static applications, this may be accomplished by averaging over a sufficiently long period of observation, but in kinematic applications, a modelling approach must be used. This paper is concerned with one such approach: the use of ray-tracing to reconstruct the error and therefore remove it. In order to apply such an approach, it is necessary to have a detailed understanding of the signal transmitted from the satellite, the reflection process, the antenna characteristics and the way that the reflected and direct signal are processed within the receiver. This paper reviews all of these and introduces a formal ray-tracing method for multipath estimation based on precise knowledge of the satellite reflector antenna geometry and of the reflector material and antenna characteristics. It is validated experimentally using GPS signals reflected from metal, water and a brick building, and is shown to be able to model most of the main multipath characteristics. The method will have important practical applications for correcting for multipath in well-constrained environments (such as at base stations for local area GPS networks, at International GNSS Service (IGS) reference stations, and on spacecraft), and it can be used to simulate realistic multipath errors for various performance analyses in high-precision positioning.

MODERN PECULIARITIES OF THE MEDICAL EXPOSURE LEVELS FORMING OF THE TATARSTAN REPUBLIC POPULATION DURING X-RAY PROCEDURES IMPLEMENTATION

Directory of Open Access Journals (Sweden)

S. A. Ryzhkin

2015-01-01

Full Text Available The purpose. The purpose of the investigation is an assessment of the peculiarities of forming and registration of the collective doses of patients and the population of the Tatarsatan Republic (RT from medical exposure and the development of measures for optimization of this radiation factor.Materials and methods. The analysis is based on the forms of the Federal statistical observation № 3-DOZ «Data on the exposure doses to patients obtained during medical radiological examination» (form № 3-DOZ and radiation-hygienic passports of RT for the period from 2006 to 2013.The results. Annually in RT there is an increase of the number of performed X-ray procedures, which reached the value of 6279696 (1.64 procedures per resident per year in 2013. During the reporting period (from 2006 to 2013 the structure of the performed X-ray procedures has also changed. It is observed that the percentage of fluorography procedures in the overall structure decreased from 41.3% to 31.3% at the same time the level of absolute value of annually performed fluorography procedures is stable. There is an increase in the absolute number of radiographic procedures performed during the period from 2578754 to 4072810 X-rays per year, that is 1.58 times higher. Absolute and relative values related to X-ray fluoroscopy examinations decreased from 1.1% to 0.7%. In contrast, the absolute number of annually performed X-ray computed tomography examinations (CT has increased over the period by 3.3 times and percentage of CT in overall structure of X-ray procedure is 2.7%. The number of special investigations has increased in 2.1 times, but the relative value remained at average level of 0.4% on general background of the increasing of X-ray activity in the region. This fact influenced the change in the radiation-hygienic indexes of medical radiation exposure of the population of RT. According to №3-DOZ forms and radiation-hygienic passports of the

Developmental long trace profiler using optimally aligned mirror based pentaprism

International Nuclear Information System (INIS)

Barber, Samuel K.; Morrison, Gregory Y.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Geckeler, Ralf D.; Buchheim, Jana; Siewert, Frank; Zeschke, Thomas

2010-01-01

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory (Nucl. Instr. and Meth. A 616, 212-223 (2010)). The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror based pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.

A recommended procedure for estimating the cosmic-ray spectral parameter of a simple power law

CERN Document Server

Howell, L W

2002-01-01

A simple power law model with single spectral index alpha sub 1 is believed to be an adequate description of the galactic cosmic-ray (GCR) proton flux at energies below 10 sup 1 sup 3 eV. Two procedures for estimating alpha sub 1 --the method of moments and maximum likelihood (ML)--are developed and their statistical performance are compared. The ML procedure is shown to be the superior approach and is then generalized for application to real cosmic-ray data sets. Several other important results, such as the relationship between collecting power and detector energy resolution and inclusion of a non-Gaussian detector response function, are presented. These results have many practical benefits in the design phase of a cosmic-ray detector as they permit instrument developers to make important trade studies in design parameters as a function of one of the science objectives.

Staff and patient exposure to X-ray radiation during cardiac procedures

International Nuclear Information System (INIS)

Jankowski, J.; Papierz, D.; Domienik, J.; Kacprzyk, J.; Tybor-Czerwinska, M.; Werduch, A.

2008-01-01

The aim of this study was to define and compare staff and patient doses during the most common types of cardiac procedures. The influence of operators' technique and quality of X-ray unit in use on doses received by the staff and patients was investigated. The study was conduced in two independent hemodynamic rooms (I and II). The doses to hand for medical staff (operators and nurses) were monitored. For hand dose assessment, ring thermoluminescent dosimeters were used. Regarding patient dosimetry, dose-area product was collected for selected procedures. The monthly hand doses ranged from 0.4 mSv to 41.2 mSv in room I and from 0.1 to 8.95 mSv in room II. On the basis of the above measurements, the annual doses were estimated. The maximum annual hand doses for the operator and for the nurse in room I were 232.8 mSv/year and 11.5 mSv/year and in room II - 29.8 mSv/year and 14.1 mSv/year, respectively. Additionally, to compare the doses received by the particular medical operators, the doses were normalized to the total workload. Hand dose per procedure ranged from 109 to 614 μSv/procedure and were significantly larger in room I. The typical DAP values (median) recorded for the CA and CA+PTCA procedures were 55 Gy/cm 2 and 171 Gy/cm 2 in room I and 35 Gy/cm 2 and 87 Gy/cm 2 in the room II, respectively. As a result of this survey, the impact of medical operator's experience as well as technique and quality of available X-ray units on doses received by staff and patients has been proven. On the basis of the above results, the special need for monitoring hand doses for medical staff, apart from the effective dose, has been recognized. (author)

Relationship of college student characteristics and inquiry-based geometrical optics instruction to knowledge of image formation with light-ray tracing

Science.gov (United States)

Isik, Hakan

This study is premised on the fact that student conceptions of optics appear to be unrelated to student characteristics of gender, age, years since high school graduation, or previous academic experiences. This study investigated the relationships between student characteristics and student performance on image formation test items and the changes in student conceptions of optics after an introductory inquiry-based physics course. Data was collected from 39 college students who were involved in an inquiry-based physics course teaching topics of geometrical optics. Student data concerning characteristics and previous experiences with optics and mathematics were collected. Assessment of student understanding of optics knowledge for pinholes, plane mirrors, refraction, and convex lenses was collected with, the Test of Image Formation with Light-Ray Tracing instrument. Total scale and subscale scores representing the optics instrument content were derived from student pretest and posttest responses. The types of knowledge, needed to answer each optics item correctly, were categorized as situational, conceptual, procedural, and strategic knowledge. These types of knowledge were associated with student correct and incorrect responses to each item to explain the existences and changes in student scientific and naive conceptions. Correlation and stepwise multiple regression analyses were conducted to identify the student characteristics and academic experiences that significantly predicted scores on the subscales of the test. The results showed that student experience with calculus was a significant predictor of student performance on the total scale as well as on the refraction subscale of the Test of Image Formation with Light-Ray Tracing. A combination of student age and previous academic experience with precalculus was a significant predictor of student performance on the pretest pinhole subscale. Student characteristic of years since high school graduation

Traces of heavy and superheavy cosmic nuclei in olivins of extraterrestial origin

International Nuclear Information System (INIS)

Ignatova, R.; Taneva, T.

1982-01-01

The paths of traces of WH nuclei from cosmic rays have been measured in olivines from the meteorites Maryalakhti, Eagle Stein, Liposki khutor with radiation ages 175, 45 and 220 million years respectively. 3 cm 3 olivines of these meteorites have been examined and more than 500 traces of nuclei with Z(>=)90 have been found measured including 3 traces 1.5-1.8 times longer than the traces created by the uranium and thorium nuclei. These traces may be left by nuclei with Z(>=)110. The crystals were chosen from localizations situated at 2-7 cm, 8-9 cm and 10-12 cm from the outside atmospheric surface of the meteorite. The abundancy of the Z(>=)50 nuclei in gigantic cosmic rays, averaged for a period of ( =)110 in galactic cosmic rays. It is 1.4 x 10 -9 from that of the iron group nuclei. (authors)

Grazing exit versus grazing incidence geometry for x-ray absorption near edge structure analysis of arsenic traces

International Nuclear Information System (INIS)

Meirer, F.; Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

2009-01-01

In the presented study the grazing exit x-ray fluorescence was tested for its applicability to x-ray absorption near edge structure analysis of arsenic in droplet samples. The experimental results have been compared to the findings of former analyses of the same samples using a grazing incidence (GI) setup to compare the performance of both geometries. Furthermore, the investigations were accomplished to gain a better understanding of the so called self-absorption effect, which was observed and investigated in previous studies using a GI geometry. It was suggested that a normal incidence-grazing-exit geometry would not suffer from self-absorption effects in x-ray absorption fine structure (XAFS) analysis due to the minimized path length of the incident beam through the sample. The results proved this assumption and in turn confirmed the occurrence of the self-absorption effect for GI geometry. Due to its lower sensitivity it is difficult to apply the GE geometry to XAFS analysis of trace amounts (few nanograms) of samples but the technique is well suited for the analysis of small amounts of concentrated samples

Fresnel diffraction correction by phase-considered iteration procedure in soft X-ray projection microscopy

International Nuclear Information System (INIS)

Shiina, Tatsuo; Suzuki, Tsuyoshi; Honda, Toshio; Ito, Atsushi; Kinjo, Yasuhito; Yoshimura, Hideyuki; Yada, Keiji; Shinohara, Kunio

2009-01-01

In soft X-ray projection microscopy, it is easy to alter the magnification by changing the distance between the pinhole and the specimen, while the image is blurred because the soft X-rays are diffracted through the propagation from specimen to CCD detector. We corrected the blurred image by the iteration procedure of Fresnel to inverse Fresnel transformation taking phase distribution of the specimen into account. The experiments were conducted at the BL-11A of the Photon Factory, KEK, Japan for the specimens such as glass-capillaries, latex-particles, dried mammalian cells and human chromosomes. Many of those blurred images were corrected adequately by the iteration procedure, though some images such as those which have high-contrast or are overlapped by small cells still remain to be improved.

Combination of ray-tracing and the method of moments for electromagnetic radiation analysis using reduced meshes

Science.gov (United States)

Delgado, Carlos; Cátedra, Manuel Felipe

2018-05-01

This work presents a technique that allows a very noticeable relaxation of the computational requirements for full-wave electromagnetic simulations based on the Method of Moments. A ray-tracing analysis of the geometry is performed in order to extract the critical points with significant contributions. These points are then used to generate a reduced mesh, considering the regions of the geometry that surround each critical point and taking into account the electrical path followed from the source. The electromagnetic analysis of the reduced mesh produces very accurate results, requiring a fraction of the resources that the conventional analysis would utilize.

Semi-empirical procedures for correcting detector size effect on clinical MV x-ray beam profiles

International Nuclear Information System (INIS)

Sahoo, Narayan; Kazi, Abdul M.; Hoffman, Mark

2008-01-01

The measured radiation beam profiles need to be corrected for the detector size effect to derive the real profiles. This paper describes two new semi-empirical procedures to determine the real profiles of high-energy x-ray beams by removing the detector size effect from the measured profiles. Measured profiles are corrected by shifting the position of each measurement point by a specific amount determined from available theoretical and experimental knowledge in the literature. The authors developed two procedures to determine the amount of shift. In the first procedure, which employs the published analytical deconvolution procedure of other investigators, the shift is determined from the comparison of the analytical fit of the measured profile and the corresponding analytical real profile derived from the deconvolution of the fitted measured profile and the Gaussian detector response function. In the second procedure, the amount of shift at any measurement point is considered to be proportional to the value of an analytical function related to the second derivative of the real profile at that point. The constant of proportionality and a parameter in the function are obtained from the values of the shifts at the 90%, 80%, 20%, and 10% dose levels, which are experimentally known from the published results of other investigators to be approximately equal to half of the radius of the detector. These procedures were tested by correcting the profiles of 6 and 18 MV x-ray beams measured by three different ionization chambers and a stereotactic field diode detector with 2.75, 2, 1, and 0.3 mm radii of their respective active cylindrical volumes. The corrected profiles measured by different detectors are found to be in close agreement. The detector size corrected penumbra widths also agree with the expected values based on the results of an earlier investigation. Thus, the authors concluded that the proposed procedures are accurate and can be used to derive the real

Study of trace element correlations with drought tolerance in different sorghum genotypes using Energy Dispersive X-Rays Fluorescence (EDXRF) technique

International Nuclear Information System (INIS)

Abu Assar, A.H.; Joseph, Daisy; Choudhury, R.K.; Saxena, A.; Suprasanna, P.; Bapat, V.A.

2000-01-01

Drought tolerant and susceptible genotypes of sorghum plants were analysed by Energy Dispersive X-Ray Fluorescence (EDXRF) technique to study the correlation of trace elements with drought tolerance capacities for sorghum plants. Samples prepared from mature seeds, young seedlings and old plants were analyzed using 109 Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9 keV Mn K α X-ray. The elements such as K, Fe, Cu, Zn, Rb and Sr and Y were seen to be present in varying concentrations in different samples. The trace element profile in the seeds of 11 genotypes and in seedlings (young and old) of four sorghum genotypes that were studied exhibited considerable variation in their concentrations. Some seed genotypes showed the presence of Hg in small amounts. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype as compared to the susceptible type. Concentration of Fe decreased with maturity in the tolerant group while it increased with maturity in the susceptible group. The genotype Arfa Gadamak (AG) showed a distinct abnormality in its young seedling with high level of Zn. (author)

Mercury and trace element fractionation in Almaden soils by application of different sequential extraction procedures

Energy Technology Data Exchange (ETDEWEB)

Sanchez, D.M.; Quejido, A.J.; Fernandez, M.; Hernandez, C.; Schmid, T.; Millan, R.; Gonzalez, M.; Aldea, M.; Martin, R.; Morante, R. [CIEMAT, Madrid (Spain)

2005-04-01

A comparative evaluation of the mercury distribution in a soil sample from Almaden (Spain) has been performed by applying three different sequential extraction procedures, namely, modified BCR (three steps in sequence), Di Giulio-Ryan (four steps in sequence), and a specific SEP developed at CIEMAT (six steps in sequence). There were important differences in the mercury extraction results obtained by the three procedures according to the reagents applied and the sequence of their application. These findings highlight the difficulty of setting a universal SEP to obtain information on metal fractions of different mobility for any soil sample, as well as the requirement for knowledge about the mineralogical and chemical characteristics of the samples. The specific six-step CIEMAT sequential extraction procedure was applied to a soil profile (Ap, Ah, Bt1, and Bt2 horizons). The distribution of mercury and major, minor, and trace elements in the different fractions were determined. The results indicate that mercury is mainly released with 6 M HCl. The strong association of mercury with crystalline iron oxyhydroxides, present in all the horizons of the profile, and/or the solubility of some mercury compounds in such acid can explain this fact. Minor mercury is found in the fraction assigned to oxidizable matter and in the final insoluble residue (cinnabar). (orig.)

Sample preparation procedure for PIXE elemental analysis on soft tissues

International Nuclear Information System (INIS)

Kubica, B.; Kwiatek, W.M.; Dutkiewicz, E.M.; Lekka, M.

1997-01-01

Trace element analysis is one of the most important field in analytical chemistry. There are several instrumental techniques which are applied for determinations of microscopic elemental content. The PIXE (Proton Induced X-ray Emission) technique is one of the nuclear techniques that is commonly applied for such purpose due to its multielemental analysis possibilities. The aim of this study was to establish the optimal conditions for target preparation procedure. In this paper two different approaches to the topic are presented and widely discussed. The first approach was the traditional pellet technique and the second one was mineralization procedure. For the analysis soft tissue such as liver was used. Some results are also presented on water samples. (author)

X-ray fluorescence imaging with synchrotron radiation

International Nuclear Information System (INIS)

Rivers, M.L.

1987-01-01

The micro-distribution of trace elements is of great interest in fields such as geochemistry, biology and material science. The synchrotron x-ray fluorescence microprobe provides a technique to quantitatively measure trace element compositions at individual points and to construct semiquantitative two dimensional maps of trace element compositions. This paper describes an x-ray fluorescence system used at the National Synchrotron Light Source

Quantification of trace arsenic in soils by field-portable X-ray fluorescence spectrometry: considerations for sample preparation and measurement conditions.

Science.gov (United States)

Parsons, Chris; Margui Grabulosa, Eva; Pili, Eric; Floor, Geerke H; Roman-Ross, Gabriela; Charlet, Laurent

2013-11-15

Recent technological improvements have led to the widespread adoption of field portable energy dispersive X-ray fluorescence (FP-XRF) by governmental agencies, environmental consultancies and research institutions. FP-XRF units often include analysis modes specifically designed for the quantification of trace elements in soils. Using these modes, X-ray tube based FP-XRF units can offer almost "point and shoot" ease of use and results comparable to those of laboratory based instruments. Nevertheless, FP-XRF analysis is sensitive to spectral interferences as well as physical and chemical matrix effects which can result in decreased precision and accuracy. In this study, an X-ray tube-based FP-XRF analyser was used to determine trace (low ppm) concentrations of As in a floodplain soil. The effect of different sample preparation and analysis conditions on precision and accuracy were systematically evaluated. We propose strategies to minimise sources of error and maximise data precision and accuracy, achieving in situ limits of detection and precision of 6.8 ppm and 14.4%RSD, respectively for arsenic. We demonstrate that soil moisture, even in relatively dry soils, dramatically affects analytical performance with a signal loss of 37% recorded for arsenic at 20 wt% soil moisture relative to dry soil. We also highlight the importance of the use of certified reference materials and independent measurement methods to ensure accurate correction of field values. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of minor and trace elements in kidney stones by x-ray fluorescence analysis

Science.gov (United States)

Srivastava, Anjali; Heisinger, Brianne J.; Sinha, Vaibhav; Lee, Hyong-Koo; Liu, Xin; Qu, Mingliang; Duan, Xinhui; Leng, Shuai; McCollough, Cynthia H.

2014-03-01

The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique.

Trace elements in airborne particles in internal industrial environments: spectrometric analysis of x-ray fluorescence (XRF)

International Nuclear Information System (INIS)

Salazar Matarrita, Alfonso

2001-01-01

Fluorescence spectroscopy x-ray, is a technique of non-destructive analysis, that allows quantitative determination of the absolute concentration of chemical elements that make up a given matrix. The detected elements depend on atomic number and energy of the secondary target used for irradiation of samples. X-rays are detected and counted in a spectroscopy system based on a multichannel analyzer, that discriminates by energy and form a spectrum of independent photopeaks, whose energy identifies the element and its intensity is proportional to its concentration. The quantification requires the irradiation and counting of a set of pattern comparators, of the same elements identified in the samples. The x-ray emission shows only during the time that the selected sample is subjected to irradiation by x-ray tube. This irradiation does not change the structure nor the chemical composition of the matrix, so the sample remains unchanged, after irradiation. This condition non-destructive characterizes the fluorescence x-ray. The trace elements present in airborne particles, are determined and collected on a Nuclepore filter. The collection sites selected are: Taller de Mecanica de Precision de la Escuela de Fisica, Universidad de Costa Rica; Taller J. V. G. Precision, San Antonio de Coronado; Taller de Muflas, MUFLASA, Alto de Guadalupe; Industria Silvania S. A., Pavas. In addition, it is attached the service rendered to the enterprise Sellos Generales S. A. The working conditions and physical conditions of facilities were considered. An aerosol sampler with a temporal variation was used. Irradiation of samples and an evaluation of the concentrations have been made. (author) [es

Technical Note : A direct ray-tracing method to compute integral depth dose in pencil beam proton radiography with a multilayer ionization chamber

NARCIS (Netherlands)

Farace, Paolo; Righetto, Roberto; Deffet, Sylvain; Meijers, Arturs; Vander Stappen, Francois

2016-01-01

Purpose: To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. Methods: Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45x45 mm(2) field-of-view) of 9x9 spots capable

Safety related to the implantation of jugular catheters for haemodialysis and usefulness of PA chest X rays post procedure

International Nuclear Information System (INIS)

Restrepo, Cesar A; Chacon, Jose Arnob; Mauricio Villota, Duvan

2007-01-01

The objective is to determine how safe the implantation of transient double lumen jugular catheters is for hemodialysis in patients with renal disease, and who require dialysis therapy and Posterior Anterior (PA) chest X-Ray post procedure. Design: observational descriptive study. Site: renal units at RTS Ltda. Sucursal Caldas (Hospital Santa Sofia y Hospital Infantil Rafael Henao Toro de la Cruz Roja). Patients: all patients with renal disease in whom it was necessary to do hemodyalitic therapy with implantation of a jugular catheter, with medical records of the events and complications that occurred during the procedure, with subsequent control AP chest X Ray and that showed reports made by the radiologist or physician who carried out the procedure, about the findings in the chest X Ray. Patients with renal disease, in whom jugular catheters had been inserted: Methods: variables such as age, gender, race, body mass index (BMI) etiology of the renal failure,time of evolution of the disease, indications for insertion, priority of catheter insertion, type of catheter inserted, amount of punctures, physician who carried out the procedure and patient's co-morbidities were analyzed. The events considered as complicated were analyzed as well as if there was any relationship with co-morbidities and the analyzed variables. Findings in the PA chest X-Ray were recorded and their relationship with the difficulties encountered during the procedure. A bi-variance analysis was done. The dependent and independent variables were classified in the nominal measurement scale. Results: 774 clinical histories were reviewed. 562 were excluded due to lack of variables and impossibility to read the notes. Men older than de 55 (45,7%). 212 (97.1%) patients with diagnosis of chronic renal disease (CRD) and in whom 238 procedures were carried out. seven patients (2,85%) had acute renal failure (ARF). The fi rst indication for central catheter insertion was in patients with chronic uremia

Magnetospherically reflected chorus waves revealed by ray tracing with CLUSTER data

Directory of Open Access Journals (Sweden)

M. Parrot

Full Text Available This paper is related to the propagation characteristics of a chorus emission recorded simultaneously by the 4 satellites of the CLUSTER mission on 29 October 2001 between 01:00 and 05:00 UT. During this day, the spacecraft (SC 1, 2, and 4 are relatively close to each other but SC3 has been delayed by half an hour. We use the data recorded aboard CLUSTER by the STAFF spectrum analyser. This instrument provides the cross spectral matrix of three magnetic and two electric field components. Dedicated software processes this spectral matrix in order to determine the wave normal directions relative to the Earth’s magnetic field. This calculation is done for the 4 satellites at different times and different frequencies and allows us to check the directions of these waves. Measurements around the magnetic equator show that the parallel component of the Poynting vector changes its sign when the satellites cross the equator region. It indicates that the chorus waves propagate away from this region which is considered as the source area of these emissions. This is valid for the most intense waves observed on the magnetic and electric power spectrograms. But it is also observed on SC1, SC2, and SC4 that lower intensity waves propagate toward the equator simultaneously with the SC3 intense chorus waves propagating away from the equator. Both waves are at the same frequency. Using the wave normal directions of these waves, a ray tracing study shows that the waves observed by SC1, SC2, and SC4 cross the equatorial plane at the same location as the waves observed by SC3. SC3 which is 30 minutes late observes the waves that originate first from the equator; meanwhile, SC1, SC2, and SC4 observe the same waves that have suffered a Lower Hybrid Resonance (LHR reflection at low altitudes (based on the ray tracing analysis and now return to the equator at a different location with a lower intensity. Similar phenomenon is observed when all SC are on the other side

Magnetospherically reflected chorus waves revealed by ray tracing with CLUSTER data

Directory of Open Access Journals (Sweden)

M. Parrot

2003-05-01

Full Text Available This paper is related to the propagation characteristics of a chorus emission recorded simultaneously by the 4 satellites of the CLUSTER mission on 29 October 2001 between 01:00 and 05:00 UT. During this day, the spacecraft (SC 1, 2, and 4 are relatively close to each other but SC3 has been delayed by half an hour. We use the data recorded aboard CLUSTER by the STAFF spectrum analyser. This instrument provides the cross spectral matrix of three magnetic and two electric field components. Dedicated software processes this spectral matrix in order to determine the wave normal directions relative to the Earth’s magnetic field. This calculation is done for the 4 satellites at different times and different frequencies and allows us to check the directions of these waves. Measurements around the magnetic equator show that the parallel component of the Poynting vector changes its sign when the satellites cross the equator region. It indicates that the chorus waves propagate away from this region which is considered as the source area of these emissions. This is valid for the most intense waves observed on the magnetic and electric power spectrograms. But it is also observed on SC1, SC2, and SC4 that lower intensity waves propagate toward the equator simultaneously with the SC3 intense chorus waves propagating away from the equator. Both waves are at the same frequency. Using the wave normal directions of these waves, a ray tracing study shows that the waves observed by SC1, SC2, and SC4 cross the equatorial plane at the same location as the waves observed by SC3. SC3 which is 30 minutes late observes the waves that originate first from the equator; meanwhile, SC1, SC2, and SC4 observe the same waves that have suffered a Lower Hybrid Resonance (LHR reflection at low altitudes (based on the ray tracing analysis and now return to the equator at a different location with a lower intensity. Similar phenomenon is observed when all SC are on the other side

Analysis of trace elements in medicinal plants with energy dispersive X-ray fluorescence

International Nuclear Information System (INIS)

Ekinci, N.; Polat, R.; Budak, G.; Ekinci, R.

2004-01-01

Mankind still depend on traditional herbal medicine for the treatment of various diseases and ailments. Elemental composition and concentration of medicinal plants have been investigated by energy dispersive X-ray fluorescence. The elements present in medicinal plants are P, Cl, K, Ca, S, Al, Ti, V, Rb, Sr, Zr, Nb, Mo, In, Sn, I and Ce. The physical basis of the used analytical method, the experimental set up and the procedure of sample preparation are presented. (author)

Estimation of viscoelastic attenuation of real seismic data by use of ray tracing software: Application to the detection of gas hydrates and free gas

Czech Academy of Sciences Publication Activity Database

Bouchaala, Fateh; Guennou, C.

2012-01-01

Roč. 344, č. 2 (2012), s. 57-66 ISSN 1631-0713 Institutional research plan: CEZ:AV0Z30120515 Keywords : viscoelastic attenuation * gas hydrates * free gas * ray tracing Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.401, year: 2012

A comparison of the performance of a fundamental parameter method for analysis of total reflection X-ray fluorescence spectra and determination of trace elements, versus an empirical quantification procedure

Science.gov (United States)

W(egrzynek, Dariusz; Hołyńska, Barbara; Ostachowicz, Beata

1998-01-01

The performance has been compared of two different quantification methods — namely, the commonly used empirical quantification procedure and a fundamental parameter approach — for determination of the mass fractions of elements in particulate-like sample residues on a quartz reflector measured in the total reflection geometry. In the empirical quantification procedure, the spectrometer system needs to be calibrated with the use of samples containing known concentrations of the elements. On the basis of intensities of the X-ray peaks and the known concentration or mass fraction of an internal standard element, by using relative sensitivities of the spectrometer system the concentrations or mass fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass per unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements to be determined are calculated during fitting a modelled X-ray spectrum to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross-sections of a peat core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi-element standard solution.

A study of accumulation of trace metals in coffee plants grown on ultisols fertilized with rock phosphates by energy dispersive x-ray fluorescence (EDXRF) technique

International Nuclear Information System (INIS)

Joseph, Daisy; Lal, Madan; D'Souza, T.J.

1995-01-01

Trace elements in soil and leaves of coffee plants have been analysed by a non-destructive Energy Dispersive X-ray Fluorescence (EDXRF) technique to study their accumulation due to repeated rock phosphate fertilization. Analysis of standard reference materials of soil and leaves through EDXRF yielded values within 5% error of the certified values. This method was therefore used to determine the trace metals (Fe, Cu, Zn, Rb, Sr, Nb, Zr and Y) concentrations of soils, rock phosphates and leaves of coffee grown in experimental ultisols. Results indicate that rock phosphate fertilization over a period of 10 years did not contribute significantly to high trace metal concentration in plants. (author). 6 refs., 5 tabs., 5 figs

Energy-dispersive X-ray fluorescence analysis of traces of heavy metals (Mn, Fe, Co, Ni, Cu, Zn, Ta, Pb, U) in mineral waters after separation on the cellulose-exchanger Hyphan

International Nuclear Information System (INIS)

Burba, P.; Lieser, K.H.

1979-01-01

Trace elements in mineral water are separated in small columns on the cellulose-exchanger Hyphan, eluted by diluted hydrochloric acid, bound on 100 mg of Hyphan by shaking and determined by energy-dispersive X-ray fluorescence. The following heavy metals can be analysed quantitatively if present in water in concentrations >= 1 ppb: Mn, Fe, Co, Ni, Cu, Zn, Ta, Pb and U. Several commercial mineral waters, a sodium chloride spring and seawater were analyzed for trace elements. The results obtained by X-ray fluorescence and by atomic absorption agree within the limits of error. (orig.) [de

Trace metal analysis in sea grasses from Mexican Caribbean Coast by particle induced X-ray emission (PIXE)

International Nuclear Information System (INIS)

Solis, C.; Issac O, K.; Martinez, A.; Lavoisier, E.; Martinez, M. A.

2008-01-01

The growing urban and tourist activity in the Mexican Caribbean coasts has resulted in an increase of chemical substances, metals in particular, discharged to the coastal waters. In order to reach an adequate management and conservation of these marine ecosystems it is necessary to perform an inventory of the actual conditions that reflect the vulnerability and the level of damage. Sea-grasses are considered good biological indicators of heavy metal contamination in marine systems. The goal of this preliminary work is to evaluate the concentrations of trace metals such as Cr, Mn, Fe, Co, Cu, Zn, and Pb in Thalassia testudinum, a very common sea-grass in the Mexican Caribbean Sea. Samples were collected from several locations in the coasts of the Yucatan Peninsula: Holbox, Blanquizal and Punta Allen, areas virtually uninfluenced by anthropogenic activities. Trace elements in different part plants were determined by particle induced X-ray emission (PIXE). This is a very suitable technique since it offers a fast, accurate and multi-element analysis. Also, the analysis by PIXE can be performed directly on powdered leaves without a laborious sample preparation. The trace metal concentration determined in sea-grasses growing in Caribbean generally fall in the range of the lowest valuables reported for sea grasses from the Gulf of Mexico. The results indicate that the studied areas do not present contamination by heavy metals. (Author)

Ray tracing method for simulation of laser beam interaction with random packings of powders

Science.gov (United States)

Kovalev, O. B.; Kovaleva, I. O.; Belyaev, V. V.

2018-03-01

Selective laser sintering is a technology of rapid manufacturing of a free form that is created as a solid object by selectively fusing successive layers of powder using a laser. The motivation of this study is due to the currently insufficient understanding of the processes and phenomena of selective laser melting of powders whose time scales differ by orders of magnitude. To construct random packings from mono- and polydispersed solid spheres, the algorithm of their generation based on the discrete element method is used. A numerical method of ray tracing is proposed that is used to simulate the interaction of laser radiation with a random bulk packing of spherical particles and to predict the optical properties of the granular layer, the extinction and absorption coefficients, depending on the optical properties of a powder material.

Quantitative analysis of crystalline pharmaceuticals in tablets by pattern-fitting procedure using X-ray diffraction pattern.

Science.gov (United States)

Takehira, Rieko; Momose, Yasunori; Yamamura, Shigeo

2010-10-15

A pattern-fitting procedure using an X-ray diffraction pattern was applied to the quantitative analysis of binary system of crystalline pharmaceuticals in tablets. Orthorhombic crystals of isoniazid (INH) and mannitol (MAN) were used for the analysis. Tablets were prepared under various compression pressures using a direct compression method with various compositions of INH and MAN. Assuming that X-ray diffraction pattern of INH-MAN system consists of diffraction intensities from respective crystals, observed diffraction intensities were fitted to analytic expression based on X-ray diffraction theory and separated into two intensities from INH and MAN crystals by a nonlinear least-squares procedure. After separation, the contents of INH were determined by using the optimized normalization constants for INH and MAN. The correction parameter including all the factors that are beyond experimental control was required for quantitative analysis without calibration curve. The pattern-fitting procedure made it possible to determine crystalline phases in the range of 10-90% (w/w) of the INH contents. Further, certain characteristics of the crystals in the tablets, such as the preferred orientation, size of crystallite, and lattice disorder were determined simultaneously. This method can be adopted to analyze compounds whose crystal structures are known. It is a potentially powerful tool for the quantitative phase analysis and characterization of crystals in tablets and powders using X-ray diffraction patterns. Copyright 2010 Elsevier B.V. All rights reserved.

Ray-tracing studies for a whole-viewing-angle retroreflector

International Nuclear Information System (INIS)

Yang, B.; Friedsam, H.

2000-01-01

The APS Survey and Alignment team uses LEICA laser trackers for the majority of their alignment tasks. These instruments utilize several different retroreflectors for tracking the path of the laser interferometer. Currently in use are open-air corner cubes with an acceptance angle of ±20 degree, corner cube prisms with an acceptance angle of ±50degree, and a Cat's eye with an acceptance angle of ±60degree. Best measurement results can be achieved by using an open-air corner cube that eliminates the need for the laser beam to travel through a different medium before it returns to the instrument detector. However, the trade off is a small acceptance angle. In order to overcome the limitations of the small acceptance angles, Takatsuji et al. has proposed the creation of a full-viewing-angle retroreflector. Based on the notion that the radius R 1 of a common Cat's eye is proportional to R 2 , one can write: R 1 = (n minus 1)R 2 . In the case that n, the refractive index of glass, equals 2, the radii R 1 and R 2 are identical, and one can create a solid sphere Cat's eye. This design has the advantages that no adhesives are used to bond the two hemispheres together, misalignments between the hemispheres are not an issue, and most importantly, larger acceptance angles are possible. This paper shows the results of their ray tracing calculations characterizing the geometrical optics

Ray tracing and Hubble diagrams in post-Newtonian cosmology

Science.gov (United States)

Sanghai, Viraj A. A.; Fleury, Pierre; Clifton, Timothy

2017-07-01

On small scales the observable Universe is highly inhomogeneous, with galaxies and clusters forming a complex web of voids and filaments. The optical properties of such configurations can be quite different from the perfectly smooth Friedmann-Lemaȋtre-Robertson-Walker (FLRW) solutions that are frequently used in cosmology, and must be well understood if we are to make precise inferences about fundamental physics from cosmological observations. We investigate this problem by calculating redshifts and luminosity distances within a class of cosmological models that are constructed explicitly in order to allow for large density contrasts on small scales. Our study of optics is then achieved by propagating one hundred thousand null geodesics through such space-times, with matter arranged in either compact opaque objects or diffuse transparent haloes. We find that in the absence of opaque objects, the mean of our ray tracing results faithfully reproduces the expectations from FLRW cosmology. When opaque objects with sizes similar to those of galactic bulges are introduced, however, we find that the mean of distance measures can be shifted up from FLRW predictions by as much as 10%. This bias is due to the viable photon trajectories being restricted by the presence of the opaque objects, which means that they cannot probe the regions of space-time with the highest curvature. It corresponds to a positive bias of order 10% in the estimation of ΩΛ and highlights the important consequences that astronomical selection effects can have on cosmological observables.

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry

International Nuclear Information System (INIS)

Kaniu, M.I.; Angeyo, K.H.; Mwala, A.K.; Mangala, M.J.

2012-01-01

Highlights: ► Chemometrics-assisted EDXRFS spectroscopy realizes direct, rapid and accurate analysis of trace bioavailable macronutrients in soils. ► The method is minimally invasive, involves little sample preparation, short analysis times and is relatively insensitive to matrix effects. ► This opens up the ability to rapidly characterize large number of samples/matrices with this method. - Abstract: Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace ‘bioavailable’ macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using 109 Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R 2 > 0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g −1 for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors’ knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices.

The determination of trace elements in uranium ores by x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

De Villiers, W. van Z.

1983-11-01

The determination of 17 trace elements (As, Ba, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, U, V, Y, Zn and Zr) in uranium ores by x-ray fluorescence spectrometry was investigated in this study. The determination of major elements was also necessary for the calculation of mass absorption coefficients. Initially a method was developed for the determination of the elements of interest in unmineralised silicates. Correction for absorption of radiation by the sample were made by means of mass absorption coefficients which were obtained from the relation between the inverse of the mass absorption coefficient and the intensity of the Compton scattering peak. The Feather and Willis method was used for determining the background intensity at the peak positions as well as for mass absorption coefficients. It was observed that the background intensity in the region of the uranium lines increases with increasing uranium content of the sample

Documentation for TRACE: an interactive beam-transport code

International Nuclear Information System (INIS)

Crandall, K.R.; Rusthoi, D.P.

1985-01-01

TRACE is an interactive, first-order, beam-dynamics computer program. TRACE includes space-charge forces and mathematical models for a number of beamline elements not commonly found in beam-transport codes, such as permanent-magnet quadrupoles, rf quadrupoles, rf gaps, accelerator columns, and accelerator tanks. TRACE provides an immediate graphic display of calculative results, has a powerful and easy-to-use command procedure, includes eight different types of beam-matching or -fitting capabilities, and contains its own internal HELP package. This report describes the models and equations used for each of the transport elements, the fitting procedures, and the space-charge/emittance calculations, and provides detailed instruction for using the code

Trace element determination in presolar SiC grains by synchrotron x-ray fluorescence: Commencement of a coordinated multimethod study

International Nuclear Information System (INIS)

Knight, K.B.; Sutton, S.R.; Newville, M.; Davis, A.M.; Dauphas, N.; Lewis, R.S.; Amari, S.; Steele, I.M.; Savina, M.R.; Pellin, M.J.

2008-01-01

We determined trace element compositions of individual ∼1-3 ?m presolar SiC grains from 6 KJG grains and 26 additionally cleaned KJG grains from the Murchison CM chondrite using nondestructive synchrotron X-ray fluorescence (SXRF). Presolar SiC grains are robust remnants of stellar matter ejected from stars. They survived processing in the early solar system and retain the nucleosynthetic fingerprints of their stellar progenitors. As such, they represent unique physical probes of the interiors of stars. Presolar SiC grains are commonly analyzed by mass spectrometric techniques that determine isotopic compositions and, to some degree, elemental concentrations. These techniques, however, are destructive, and can be subject to matrix effects. Elemental composition data on presolar grains remain scarce and affected by contamination and analytical artifacts. In addition, contamination has plagued isotopic characterization of some elements such as Mo and Ba. We determined trace element compositions of individual ∼1-3 (micro)m presolar SiC grains from the Murchison CM chondrite using nondestructive synchrotron X-ray fluorescence (SXRF). Samples included the KJG fraction, and a second KJG fraction that underwent additional cleaning. As every cleaning step results in some grain loss, one goal of this study was to justify additional cleaning of grains. Six KJG grains and 26 additionally cleaned KJG grains were analyzed, with location and identities of individual grains noted for future correlated isotopic study.

Emergency procedures

International Nuclear Information System (INIS)

Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

2004-01-01

The following subjects are discussed - Emergency Procedures: emergency equipment, emergency procedures; emergency procedure involving X-Ray equipment; emergency procedure involving radioactive sources

Commuting quantum traces: the case of reflection algebras

Energy Technology Data Exchange (ETDEWEB)

Avan, Jean [Laboratory of Theoretical Physics and Modelization, University of Cergy, 5 mail Gay-Lussac, Neuville-sur-Oise, F-95031, Cergy-Pontoise Cedex (France); Doikou, Anastasia [Theoretical Physics Laboratory of Annecy-Le-Vieux, LAPTH, BP 110, Annecy-Le-Vieux, F-74941 (France)

2004-02-06

We formulate a systematic construction of commuting quantum traces for reflection algebras. This is achieved by introducing two dual sets of generalized reflection equations with associated consistent fusion procedures. Products of their respective solutions yield commuting quantum traces.

Multilayer X-ray imaging systems

Science.gov (United States)

Shealy, D. L.; Hoover, R. B.; Gabardi, D. R.

1986-01-01

An assessment of the imaging properties of multilayer X-ray imaging systems with spherical surfaces has been made. A ray trace analysis was performed to investigate the effects of using spherical substrates (rather than the conventional paraboloidal/hyperboloidal contours) for doubly reflecting Cassegrain telescopes. These investigations were carried out for mirrors designed to operate at selected soft X-ray/XUV wavelengths that are of significance for studies of the solar corona/transition region from the Stanford/MSFC Rocket X-Ray Telescope. The effects of changes in separation of the primary and secondary elements were also investigated. These theoretical results are presented as well as the results of ray trace studies to establish the resolution and vignetting effects as a function of field angle and system parameters.

A model of polarized-beam AGS in the ray-tracing code Zgoubi

Energy Technology Data Exchange (ETDEWEB)

Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ahrens, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Glenn, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2016-07-12

A model of the Alternating Gradient Synchrotron, based on the AGS snapramps, has been developed in the stepwise ray-tracing code Zgoubi. It has been used over the past 5 years in a number of accelerator studies aimed at enhancing RHIC proton beam polarization. It is also used to study and optimize proton and Helion beam polarization in view of future RHIC and eRHIC programs. The AGS model in Zgoubi is operational on-line via three different applications, ’ZgoubiFromSnaprampCmd’, ’AgsZgoubiModel’ and ’AgsModelViewer’, with the latter two essentially interfaces to the former which is the actual model ’engine’. All three commands are available from the controls system application launcher in the AGS ’StartUp’ menu, or from eponymous commands on shell terminals. Main aspects of the model and of its operation are presented in this technical note, brief excerpts from various studies performed so far are given for illustration, means and methods entering in ZgoubiFromSnaprampCmd are developed further in appendix.

Exposure to rays and radiation hazards in connection with diagnostic X-ray procedures in children

International Nuclear Information System (INIS)

Protzer, K.

1988-01-01

In this study, figures and data about radiation exposures for diagnostic purposes are surveyed that were collected in connection with X-ray procedures in children. The data were sorted according to body regions and techniques required for their examination so as to permit separate analyses of procedures in the urogenital tract (intravenous urogramme, micturition cystourethrography), thorax (angiocardiogramme, thoractic aortogramme, examinations using cardiac catheters), gastrointestinal system (fluoroscopy and contrast-enhanced irrigoscopy), pelvis (survey radiography), skull (computed tomography) as well as in miscellaneous group of further origins. The second part of the report discusses the uncertainties surrounding the assessment of radiation hazards and indicated radiation doses. A formula is represented for the calculation of life-time reductions that can be applied to any type of cancer and embraces a number of factors like life expectancy at age X, the patient's age at the time of radiotherapy, the five-year-survival rate for the condition under investigation and the diseased organ. At the end of the study, some methods are pointed out that may be helpful in limiting radiation exposure. (KST) [de

Incorporation of Trace Elements in Ancient and Modern Human Bone: An X-Ray Absorption Spectroscopy Study

Science.gov (United States)

Pingitore, N. E.; Cruz-Jimenez, G.; Price, T. D.

2001-12-01

X-ray absorption spectroscopy (XAS) affords the opportunity to probe the atomic environment of trace elements in human bone. We are using XAS to investigate the mode(s) of incorporation of Sr, Zn, Pb, and Ba in both modern and ancient (and thus possibly altered) human and animal bone. Because burial and diagenesis may add trace elements to bone, we performed XAS analysis on samples of pristine contemporary and ancient, buried human and animal bone. We assume that deposition of these elements during burial occurs by processes distinct from those in vivo, and this will be reflected in their atomic environments. Archaeologists measure strontium in human and animal bone as a guide to diet. Carnivores show lower Sr/Ca ratios than their herbivore prey due to discrimination against Sr relative to Ca up the food chain. In an initial sample suite no difference was observed between modern and buried bone. Analysis of additional buried samples, using a more sensitive detector, revealed significant differences in the distance to the second and third neighbors of the Sr in some of the buried samples. Distances to the first neighbor, oxygen, were similar in all samples. Zinc is also used in paleo-diet studies. Initial x-ray absorption spectroscopy of a limited suite of bones did not reveal any differences between modern and buried samples. This may reflect the limited number of samples examined or the low levels of Zn in typical aqueous solutions in soils. Signals from barium and lead were too low to record useful XAS spectra. Additional samples will be studied for Zn, Ba, and Pb. We conducted our XAS experiments on beam lines 4-1 and 4-3 at the Stanford Synchrotron Radiation Laboratory. Data were collected in the fluorescence mode, using a Lytle detector and appropriate filter, and a solid state, 13-element Ge-detector.

Determination of trace elements and heavy metals in sediment using x-ray fluorescence

International Nuclear Information System (INIS)

Sidahmed, Muataz Ahmed Ibrahem

2014-01-01

In this study, 30 sediment samples were taken randomly from the area of Suba south of Khartoum state. Trace elements and heavy metal were determined in sediments samples using x-ray fluoresce spectroscopy (X RF). K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were determined by X RF. Standard Reference Material (SRM) from international Atomic Energy Agency (IAEA-Soil-7) has been used to achieve accuracy of X RF method. Measured values were found in agreements with certified values. The average elemental concentrations of K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were 5882.7, 20703.3, 6264.3, 460.97, 26713.3, 7.7, 43.4, 18.6, 28.6, 144.8, and 173.06, respectively. Correlation between elements was performed also cluster analysis was used to check the similarly between the samples result. The result of study were compared with previous studies and the concentrations of some elements found to be similar.(Author)

Exposure measurement in the neighboring hospital beds during an x-ray procedure in hospitalization unit

Energy Technology Data Exchange (ETDEWEB)

Goto, Rafael E.; Capeleti, Felipe F.; Cabete, Henrique V., E-mail: rafael.goto@fcmsantacasasp.edu.br, E-mail: felipe.capeleti@fcmsantacasasp.edu.br, E-mail: henrique@gmpbrasil.com.br [Faculdade de Ciencias Medicas da Santa Casa Sao Paulo, SP (Brazil); GMP Consultoria em Radioprotecao e Fisica Medica e Assessoria LTDA, Sao Paulo, SP (Brazil)

2017-11-01

There are lots of discussion about the exposure in hospitalization units in Brazil, especially around labor legislation and economic advantages of unhealthiness. With the attention focused on hospitalized patients, there were measured the exposure in neighboring beds of the patient submitted to an X-ray procedure with a mobile X-ray system that could be used to illustrate the discussion with consistent values. The most common X-ray procedure made in hospitalization units are chests images with techniques between 70 to 120 kV and 5 to 20 mAs. The measurement was made during routine exposure and simulations using a scattering phantom with Radcal AccuPro electrometer and 1800cc ionization chamber in a private hospital and a philanthropic hospital, both in Sao Paulo, Brazil. The ionization chambers are placed at 2 meters distance of the patient exposed of both sides during the routine procedure. During the simulation, a nylon phantom of 20 centimeters thick and 30 x 30 cm² size was placed on the bed, a typical exposure technique was used and the exposure was measured surrounding the phantom at 0.6, 1.0 and 2.0 meters distance for scattered radiation characterization. Initial results showed that the neighboring exposure at about 2 meters distance from the exposed patient bed have low values, even when exposure is integrated during the length of hospital stay. Therefore, the exposure in hospitalization units are very low compared to the exams doses. (author). (author)

Determination of trace elements in tea by wavelength dispersive X-ray fluorescence spectroscopy

International Nuclear Information System (INIS)

Gong Chunhui; Zeng Guoqiang; Ge Liangquan; Li Jun; Wen Ziqiang

2013-01-01

Background: Measuring trace elements in tea can determine its nutritional value, verify the authenticity and place of origin, and detect the poisonous and harmful elements remaining in tea due to the application of chemical fertilizers and pesticides. Purpose: In order to reduce the time for sample preparation and the costs of equipment maintenance, wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy was used to determine the trace elements in tea which is rapid, non-destructive and accurate. The contents of more than 20 elements can be measured simultaneously. Methods: Sample pieces were made by the sample preparation method of boric acid rebasing. To avoid the exogenous environmental pollution subjected in the growth of tea, we removed the residual dust of the tea by cleaning it. According to the principle that the standard samples should be similar types with the samples to be analyzed to select standard samples. The curves were built by SuperQ, which contained compiling the measurement conditions, establishing the measurement conditions, checking the angles, determining the measurement times, checking PHD and adding the contents and the names of sample pieces. The accuracy of the method can be obtained by comparing the measured values with the trace element contents of standard samples. The contents of trace elements in tea determined by WDXRF can be used to classify the tea attribution and the tea species through cluster analysis of SPSS software. Results: (1) The results show that the biggest relative standard deviation is 0.43% of Pb, and the precision is very good. (2) Five kinds of tea are taken separately in Fujian and Yunnan, measured three times with the established working curves. And tree diagram of cluster analysis can be obtained with SPSS software to analyze the measured average values with cluster analysis, coupling method between groups and Minkowski distance measurement techniques. It can be seen that in the tree diagram, when the

Trace analysis in the atmosphere, water bodies and uranium ores by means of X-ray fluorescence

International Nuclear Information System (INIS)

Perez Novara, A.M.

1986-01-01

Analysis with X-ray fluorescence is an instrumental method that evaluates concentrations, at trace levels, of elements in samples of all kinds. The applications of this method are broad, specially useful in the analysis of metals as contaminators in air and water, and as impurities in minerals. The preparation of the samples is very important to obtain good accuracy, and at the same time, you should make a series of standards of known concentrations so you can compare the counting of each sample against the standard, for each of the elements. You should make, depending on the nature of the sample, several corrections with respect to the background, interferences, overlaps, or for effects of a third element. (author)

A new method for automatic discontinuity traces sampling on rock mass 3D model

Science.gov (United States)

Umili, G.; Ferrero, A.; Einstein, H. H.

2013-02-01

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

International Nuclear Information System (INIS)

Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

2010-01-01

Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2 O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different (α = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 μg g -1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of 'Citrus Leaves' and a blank were treated in the same way.

Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

Energy Technology Data Exchange (ETDEWEB)

Martinez, T., E-mail: tmc@servidor.unam.m [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Lartigue, J. [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico, D.F. 04510 (Mexico); Zarazua, G.; Avila-Perez, P. [National Institute of Nuclear Research. Ocoyoacac, Edo. de Mexico, 05045 (Mexico); Navarrete, M. [Facultad de Quimica, Departamento de Quimica Inorganica y Nuclear. Universidad Nacional Autonoma de Mexico, Mexico, D.F. 04510 (Mexico); Tejeda, S. [National Institute of Nuclear Research. Ocoyoacac, Edo. de Mexico, 05045 (Mexico)

2010-06-15

Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO{sub 3} and H{sub 2}O{sub 2} (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ({alpha} = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 {mu}g g{sup -1}. A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of 'Citrus Leaves' and a blank were treated in the same way.

Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

Science.gov (United States)

Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

2010-06-01

Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ( α = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 μg g - 1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of "Citrus Leaves" and a blank were treated in the same way.

Application of neutron activation and high resolution X-ray spectrometry to the development of analytical methods suitable for the assay of trace elements in biological materials. Part of a coordinated programme on comparative methods for the study of trace elements in human nutrition

International Nuclear Information System (INIS)

Mantel, J.

1980-12-01

A new method for determining trace elements in biological materials by instrumental neutron activation analysis (INAA) has been investigated. This method is based on the measurement of low-energy X-rays emitted by the sample after appropriate activation with thermal neutrons. The X-rays were detected by a Si(Li) diode connected to a multichannel analyser. The background in the energy region of interest was reduced by means of an electromagnet which deflects high-energy beta-particles away from the detector. This method of measurement has been evaluated by application to a number of different biological reference materials. The use of the electromagnet for background reduction was shown to be extremely effective for several radionuclides that are common sources of disturbance in INAA. For 32 P the background was only 0.8% of its original value. For real samples the background reduction depends somewhat on the matrix and therefore varies from one material to another. Practical detection limits for typical biological materials were derived for 18 different trace elements. The use of a perspex absorber was also considered as an alternative to magnetic deflection of the beta rays. In practice, magnetic deflection is preferable for the lower-energy X-ray emitters such as the activation products of Co, Cr, Cu and Zn

Ray tracing and Hubble diagrams in post-Newtonian cosmology

Energy Technology Data Exchange (ETDEWEB)

Sanghai, Viraj A.A.; Clifton, Timothy [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS (United Kingdom); Fleury, Pierre, E-mail: v.a.a.sanghai@qmul.ac.uk, E-mail: pierre.fleury@unige.ch, E-mail: t.clifton@qmul.ac.uk [Départment de Physique Théorique, Université de Genève, 24 quai Ernest-Ansermet, 1211 Genève 4 (Switzerland)

2017-07-01

On small scales the observable Universe is highly inhomogeneous, with galaxies and clusters forming a complex web of voids and filaments. The optical properties of such configurations can be quite different from the perfectly smooth Friedmann-Lemaȋtre-Robertson-Walker (FLRW) solutions that are frequently used in cosmology, and must be well understood if we are to make precise inferences about fundamental physics from cosmological observations. We investigate this problem by calculating redshifts and luminosity distances within a class of cosmological models that are constructed explicitly in order to allow for large density contrasts on small scales. Our study of optics is then achieved by propagating one hundred thousand null geodesics through such space-times, with matter arranged in either compact opaque objects or diffuse transparent haloes. We find that in the absence of opaque objects, the mean of our ray tracing results faithfully reproduces the expectations from FLRW cosmology. When opaque objects with sizes similar to those of galactic bulges are introduced, however, we find that the mean of distance measures can be shifted up from FLRW predictions by as much as 10%. This bias is due to the viable photon trajectories being restricted by the presence of the opaque objects, which means that they cannot probe the regions of space-time with the highest curvature. It corresponds to a positive bias of order 10% in the estimation of Ω{sub Λ} and highlights the important consequences that astronomical selection effects can have on cosmological observables.

TXRF, PIXE and EDXRF: a first step towards normalization of x-ray spectrometry for chemical analysis

International Nuclear Information System (INIS)

Barreiros, M.A.; Costa, M.M.; Palha, M.; Pinheiro, T.; Araujo, M.F.; Silva, R.C. da

2000-01-01

Nowadays, many research studies rely on analytical measurements to which x-ray spectrometry techniques are particularly adequate. Because they are multi-elemental, versatile, fast and can reach low detection limits they are often applied to environmental and biomedical studies. Besides, they are able to provide reliable and accurate results. As also occurs with other analytical procedures, the quality assurance for non-routine analysis in R and D laboratories, is much less well established. when compared with routine analytical work. Thus, it is of foremost importance, to set the major quality parameters that significantly affect the quality of results. In addition, there is a need to apply the new concepts of trace ability and uncertainty to these techniques. This work reports on the reliability of TXRF, PIXE and EDXRF measurements by evaluating the uncertainty and trace ability for elemental analysis. The set of experimental and statistical procedures used to ensure the quality of results relative to the proposed objectives, as well as the methods applied to estimate the uncertainties will be presented and discussed. The sample preparation procedures, analytical calibration and spectral evaluation will be the parameters examined in this inter-laboratory study. The sample preparation procedures comprise pressure acid digestion and pelletizing for solid samples. The internal quality control for analytical calibration and spectral analysis is performed using certified reference materials and standard solutions. The goal of this work is to present a first step towards normalization of x-ray spectrometry techniques for chemical analysis. (author)

Analysis of nutrition-relevant trace elements in human blood and serum by means of total reflection X-ray fluorescence (TXRF) spectroscopy

International Nuclear Information System (INIS)

Stosnach, Hagen; Mages, Margarete

2009-01-01

In clinical service laboratories, one of the most common analytical tasks with regard to inorganic traces is the determination of the nutrition-relevant elements Fe, Cu, Zn, and Se. Because of the high numbers of samples and the commercial character of these analyses, a time-consuming sample preparation must be avoided. In this presentation, the results of total reflection X-ray fluorescence measurements with a low-power system and different sample preparation procedures are compared with those derived from analysis with common methods like Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The results of these investigations indicate that the optimal total reflection X-ray fluorescence analysis of the nutrition-relevant elements Fe, Cu, Zn, and Se can be performed by preparing whole blood and serum samples after dilution with ultrapure water and transferring 10 μl of internally standardized sample to an unsiliconized quartz glass sample carrier with subsequent drying in a laboratory oven. Suitable measurement time was found to be 600 s. The enhanced sample preparation by means of microwave or open digestion, in parts combined with cold plasma ashing, led to an improvement of detection limits by a factor of 2 for serum samples while for whole blood samples an improvement was only observed for samples prepared by means of microwave digestion. As the matrix elements P, S, Cl, and for whole blood Fe have a major influence on the detection limits, most probably a further enhancement of analytical quality requires the removal of the organic matrix. However, for the routine analysis of the nutrition-relevant elements, the dilution preparation was found to be sufficient.

PIXE trace element analysis of a selection of wines

International Nuclear Information System (INIS)

Houdayer, A.; Hinrichsen, P.F.; Martin, J.P.; Belhadfa, A.

1987-01-01

The University of Montreal EN Tandem accelerator and a Si (Li) X-ray detector were used for a PIXE (Proton Induced X-ray emission) trace element analysis of a selection of wines. Quantitative measurements of the concentrations of the sixteen trace elements Na, Mg, Al, Si, P, S, Cl, K, Ca, Cr, Mn, Fe, Co, Cu, Zn, and Br were made. To optimize the sensitivity, spectra were recorded at 1.0 MeV proton energy for elements with Z 19. The absolute concentrations of the trace elements were determined by doping the samples of wine with 1000 ppm of vanadium for the 1.0 MeV bombardments, and 1000 ppm of yttrium for the 3.0 MeV irradiations. The targets were prepared by depositing a few microliters of the wine onto a Nuclepore filter

Analysis of trace elements in ceramic prints on automobile glasses for forensic examination using high-energy synchrotron radiation x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Nishiwaki, Yoshinori; Takatsu, Masahisa; Miyamoto, Naoki; Watanabe, Seiya; Shimoda, Osamu; Muratsu, Seiji; Nakanishi, Toshio; Nakai, Izumi

2007-01-01

This study revealed that high-energy SRXRF (synchrotron radiation X-ray fluorescence spectrometry) utilizing 75.5 keV X-rays of SPring-8 is a powerful technique for trace elemental analysis of ceramic prints on automotive glasses for forensic examination. Fragments of 99 ceramic prints were collected from automobiles of various manufacturers, types and model years. Their major heavy element-components were found to be either Pb or Bi. Because of recent environment protection movement for lead-free material, there was a tendency of the shift of material from the Pb Type to the Bi Type with years of the production. A utilization of 75.5 keV X-rays as excitation source allowed us to detect trace heavy-elements, such as Sb, La, Ce, Hf and W, as well as relatively light-elements, such as V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr and Mo, in samples using K series of XRF emission lines. XRF intensities of these elements normalized by those of the major heavy-elements (Pb or Bi) became characteristic finger prints, showing the identity of each sample with a size of less than 0.5x0.5 mm 2 . The mean relative standard deviations of the normalized XRF intensities measured for the three fragments of each sample were less than 9.3%. These results show that the ceramic prints on automobile glasses contain rich elemental information for discrimination, and therefore the materials can be important evidence for practical forensic examinations. (author)

Electronprobe X-ray microanalysis of biological specimens improvement of a number of quantification procedures

International Nuclear Information System (INIS)

Boekestein, A.

1984-01-01

In this thesis an investigation is described to establish which quantification procedures can be used in the X-ray microanalysis of biological specimens. Two classes of specimens have been distinguished from each other, i.e. thick specimens (opaque to the beam electrons) and thin specimens (transparent to the beam electrons). (Auth.)

RAY-UI: A powerful and extensible user interface for RAY

Energy Technology Data Exchange (ETDEWEB)

Baumgärtel, P., E-mail: peter.baumgaertel@helmholtz-berlin.de; Erko, A.; Schäfers, F. [Institute for Nanometre Optics and Technology Helmholtz Zentrum Berlin für Materialien und Energie Albert-Einstein-Str. 15, 12489 Berlin (Germany); Witt, M. [Department Operation Accelerator BESSY II Helmholtz Zentrum Berlin für Materialien und Energie Albert-Einstein-Str. 15, 12489 Berlin (Germany); Baensch, J.; Fabarius, M.; Schirmacher, H. [Fachbereich VI – Informatik und Medien Beuth Hochschule für Technik Berlin, Luxemburger Str. 10, 13353 Berlin (Germany)

2016-07-27

The RAY-UI project started as a proof-of-concept for an interactive and graphical user interface (UI) for the well-known ray tracing software RAY [1]. In the meantime, it has evolved into a powerful enhanced version of RAY that will serve as the platform for future development and improvement of associated tools. The software as of today supports nearly all sophisticated simulation features of RAY. Furthermore, it delivers very significant usability and work efficiency improvements. Beamline elements can be quickly added or removed in the interactive sequence view. Parameters of any selected element can be accessed directly and in arbitrary order. With a single click, parameter changes can be tested and new simulation results can be obtained. All analysis results can be explored interactively right after ray tracing by means of powerful integrated image viewing and graphing tools. Unlimited image planes can be positioned anywhere in the beamline, and bundles of image planes can be created for moving the plane along the beam to identify the focus position with live updates of the simulated results. In addition to showing the features and workflow of RAY-UI, we will give an overview of the underlying software architecture as well as examples for use and an outlook for future developments.

Fully automated laser ray tracing system to measure changes in the crystalline lens GRIN profile.

Science.gov (United States)

Qiu, Chen; Maceo Heilman, Bianca; Kaipio, Jari; Donaldson, Paul; Vaghefi, Ehsan

2017-11-01

Measuring the lens gradient refractive index (GRIN) accurately and reliably has proven an extremely challenging technical problem. A fully automated laser ray tracing (LRT) system was built to address this issue. The LRT system captures images of multiple laser projections before and after traversing through an ex vivo lens. These LRT images, combined with accurate measurements of the lens geometry, are used to calculate the lens GRIN profile. Mathematically, this is an ill-conditioned problem; hence, it is essential to apply biologically relevant constraints to produce a feasible solution. The lens GRIN measurements were compared with previously published data. Our GRIN retrieval algorithm produces fast and accurate measurements of the lens GRIN profile. Experiments to study the optics of physiologically perturbed lenses are the future direction of this research.

Comparative evaluation of trace elements in blood

International Nuclear Information System (INIS)

Goeij, J.J.M. de; Tjioe, P.S.; Pries, C.; Zwiers, J.H.L.

1976-01-01

The Interuniversitair Reactor Instituut and the Centraal Laboratorium TNO have carried out a common investigation on neutron-activation-analytical procedures for the determination of trace elements in blood. A comparative evaluation of five methods, destructive as well as non-destructive, is given. The sensitivity and reproducibility of the procedures are discussed. By combining some of the methods it is possible, starting with 1 ml blood, to give quantitative information on 14 important trace elements: antimony, arsenic, bromine, cadmium, cobalt, gold, copper, mercury, molybdenum, nickel, rubidium, selenium, iron and zinc. The methods have also been applied to sodium, chromium and potassium

Trace element studies at University of Pittsburgh

International Nuclear Information System (INIS)

Cohen, B.L.; Chan, K.C.; Shabason, L.; Wedberg, G.; Rudolph, H.

1974-01-01

Seven areas of research are discussed. A method was developed for analyzing samples for their major constituent elements by irradiating with protons and detecting prompt gamma rays, mostly produced in (p,p'γ) reactions. Among other applications, the method was used to analyze air particulates for C, N, O, Al, Si, S, Co, and Fe. Trace element analysis by proton or alpha particle induced x-ray fluorescence was used on thin samples in a study of the variations of Pb, Br, Fe, and Zn in air particulates as a function of time. Among other applications this method was also used in studying trace elements in rainwater. An x-ray fluorescence method that is effective in the analysis of thick samples was developed. A method based on measuring energies of elastically scattered protons was developed for the analysis of light elements. The use of proton and neutron activation analyses, as well as methods for studying depth profiles for hydrogen and helium in materials are discussed

Recommended safety procedures for the selection, installation and use of baggage inspection x-ray equipment

International Nuclear Information System (INIS)

1978-05-01

Good X-ray equipment alone will not preclude unnecessary exposure to x-radiation. The equipment must be installed, maintained and used by adequately trained personnel, with due regard for the inherent hazards of such equipment and an appreciation of the need to observe proper operational procedures. It is the intent of this Code to define equipment specifications and conditions of installation and use for baggage inspection X-ray equipment, such that the hazard to operating personnel and the general public from such devices remains negligibly small. (auth)

The primary exposure standard of ENEA for medium energy X-ray: characteristics and measurements procedures

International Nuclear Information System (INIS)

Laitano, R.F.; Toni, M.P.

1983-01-01

A description is given of a medium energy X-ray free-air chamber used, as primary exposure standard, at the Laboratorio di Metrologia delle Radiazioni Ionizzanti of the Enea in Italy. The main features of an X-ray facility for the production of radiation between 40 KeV and 400 KeV are also described. The measurements procedures are then analyzed with respect to the realization of the exposure unit in the relevant energy range. Finally the results of some international comparisons are reported

Stratospheric particles: Synchrotron x-ray fluorescence determination of trace element contents

International Nuclear Information System (INIS)

Sutton, S.R.; Flynn, G.J.

1987-01-01

The first trace element analyses on stratospheric particles using synchrotron x-ray fluorescence (SXRF) are reported. Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Se and Br were detected. Concentrations for chondritic particle U2022G1 are within a factor of 1.7 of CI for all elements detected with the exception of Br which is 37 times CI. Chondritic particle W7029*A27 is also near CI for Cr, Mn, Fe, Ni, Cu, Zn and Ge but enriched in Ga, Se, and Br by factors of 5.8, 3.5 and 8.4, respectively. The third particle of the cosmic dust class also showed high Br enriched relative to CI by a factor of 28. Br was also detected at a high level in an aluminum-rich particle classified as probable artificial terrestrial contamination but exhibiting a chondritic Fe/Ni ratio. Br was not detected in a fifth particle also classified terrestrial and exhibiting a crustal Fe/Ni ratio. If the high Br has a pre-terrestrial origin, the ubiquity of the effect suggests that a large fraction of the chondritic interplanetary dust particles derive from a parent body (bodies) not sampled in the meteorite collection. 26 refs., 3 figs., 3 tabs

Trace-element analysis of uranium ores by x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Coetzee, P.P.; De Villiers, W.v Z.

1985-01-01

The determination of seventeen trace elements (As, Ba, Co, Cr, Cu, Mo, Nb, Ni, Pb, Sr, Th, U, V, Y, Zn, and Zr) in uranium ores by x-ray fluorescence spectrometry was investigated. For the elements with analyte lines in the vicinity of the U-L lines, large overlap corrections were necessary and only a few completely interference-free background positions were available. Consequently, the Feather and Willis method was used for determining the background intensity at the peak positions as well as mass absorption coefficients. As a result of the presence of the U-L absorption edges, both primary and secondary mass absorption coefficients had to be used for matrix corrections. Furthermore, it was observed that the background intensity in the region of the uranium lines increased with increasing uranium content of the sample, instead of the expected decrease due to the increasing mass absorption coefficient. This was attributed to the scattering of uranium lines in the spectrometer chamber. A method was developed to correct the measured intensities for this effect. The contribution from the scattering of uranium lines to the measured intensity at the various 20 positions was determined on samples with different uranium concentrations and for which the mass absorption coefficients and concentrations of the various elements were known

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry

Energy Technology Data Exchange (ETDEWEB)

Kaniu, M.I., E-mail: ikaniu@uonbi.ac.ke [Institute of Nuclear Science and Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Angeyo, K.H. [Department of Physics, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Mwala, A.K. [Department of Land Resource Management and Agricultural Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Mangala, M.J. [Institute of Nuclear Science and Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya)

2012-06-04

Highlights: Black-Right-Pointing-Pointer Chemometrics-assisted EDXRFS spectroscopy realizes direct, rapid and accurate analysis of trace bioavailable macronutrients in soils. Black-Right-Pointing-Pointer The method is minimally invasive, involves little sample preparation, short analysis times and is relatively insensitive to matrix effects. Black-Right-Pointing-Pointer This opens up the ability to rapidly characterize large number of samples/matrices with this method. - Abstract: Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using {sup 109}Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R{sup 2} > 0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 {mu}g g{sup -1} for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated

Assessment of trace element concentration distribution in human placenta by wavelength dispersive X-ray fluorescence: Effect of neonate weight and maternal age

International Nuclear Information System (INIS)

Ozdemir, Yueksel; Boerekci, Buenyamin; Levet, Aytac; Kurudirek, Murat

2009-01-01

Trace element status in human placenta is dependent on maternal-neonatal characteristics. This work was undertaken to investigate the correlation between essential trace element concentrations in the placenta and maternal-neonatal characteristics. Placenta samples were collected from total 61 healthy mothers at gestation between 37 and 41 weeks. These samples were investigated with the restriction that the mother's age was 20-40 years old and the neonate's weight was 1-4 kg. Percent concentrations of trace elements were determined using wavelength dispersive X-ray fluorescence (WDXRF). The placenta samples were prepared and analyzed without exposure to any chemical treatment. Concentrations of Fe, Cu and Zn in placenta tissues were found statistically to vary corresponding to the age of the mother and weight of the neonate. In the subjects, the concentration of Fe and Cu were increased in heavier neonates (p<0.05) and the concentration of Zn was increased with increasing mother age (p<0.05). Consequently, the Fe, Cu and Zn elements appear to have interactive connections in human placenta.

Application of neutron activation techniques and x-ray energy dispersion spectrometry, in analysis of metallic traces adsorbed by chelex-100 resin

International Nuclear Information System (INIS)

Fernandes, Jair C.; Amaral, Angela M.; Magalhaes, Jesus C.; Pereira, Jose S.J.; Silva, Juliana B. da; Auler, Lucia M.L.A.

2000-01-01

In this work, the authors have investigated optimal conditions of adsorption for several ion metallic groups (cations of heavy metals and transition metals, oxyanions metallics and metalloids and cations of rare earths), as traces (ppb), withdrawn and in mixture of groups, by chelex-100 resin. The experiments have been developed by bath techniques in ammonium acetate tamponade solution 40 mM pH 5,52 content 0,5 g of chelex-100 resin. After magnetic agitation for two hours, resins were dried and submitted to X-ray energy dispersion spectrometry, x-ray fluorescence spectrometry and neutron activation analysis. The results have demonstrated that chelex-100 resin adsorb quantitatively transition element groups and rare earth groups in two cases (withdrawn and simultaneously adsorption)

Assessment and modifications of digestion procedures to determine trace elements in urine of hypertensive and diabetes mellitus patients

Directory of Open Access Journals (Sweden)

Awad Abdalla Momen

2013-01-01

Full Text Available Context: There is accumulating evidence that the metabolism of several trace elements like Cr, Cu, Pb, Cd, Co, Mn and Zn might have specific roles in the pathogenesis and progress of many diseases like hypertension (HTN and diabetes mellitus (DM. Objectives: To provide a fast, efficient, sensitive, and reliable analytical procedure for trace element determination in urine samples of HTN and DM patients using inductively coupled plasma optical emission spectrometry (ICP-OES. Setting and Design: The ICP-OES operating conditions were optimised and carefully selected in order to maximise the sensitivity, precision and accuracy. Factors affecting analytical and biological variability of the concentrations under study were discussed and carefully optimised. Materials and Methods: Different digestion procedures with acids and oxidising reagents were tested. The suitable procedure ICP-OES was selected, carefully modified and applied. The validity and accuracy of the different elements were determined by spiking of samples with known amounts of multi-element standard solution. Statistical Analysis: Student t-test and analysis of variance (ANOVA test were used for analysis. Microsoft Excel was used to assess the significance of the difference between variables. The concentrations obtained were expressed as mean value ± standard deviation (P = 0.05. Results: The results of this study showed that the mean concentrations of Cd, Zn, Pb, Cu, Cr and Mn in urine from both HTN (study group A and DM (study group B patients were higher than the corresponding values observed in the control group. However, while the mean value of Co was low as compared to the control group, the differences found were not significant (P = 0.05. Conclusion: The method used had excellent sensitivity, multi-element data could be obtained with very short acquisition time. The elements Cr, Cd, Pb and Zn might have specific roles in the pathogenesis and progress of HTN and DM. Further

Total-reflection x-ray fluorescence with a brillant undulator x-ray source

International Nuclear Information System (INIS)

Sakurai, K.; Eba, H.; Numako, C.; Suzuki, M.; Inoue, K.; Yagi, N.

2000-01-01

Total-reflection x-ray fluorescence (TXRF) is a highly sensitive technique for analyzing trace elements, because of the very low background from the sample support. Use of third-generation synchrotron x-ray source could further enhance the detection power. However, while such high sensitivity permits the detection of signals from trace elements of interest, it also means that one can observe weak parasitic x-rays as well. If the sample surface becomes even slightly contaminated, owing to air particulates near the beamline, x-ray fluorescence lines of iron, zinc, copper, nickel, chromium, and titanium can be observed even for a blank sample. Another critical problem is the low-energy-side tail of the scattering x-rays, which ultimately restricts the detection capability of the technique using a TXRF spectrometer based on a Si(Li) detector. The present paper describes our experiments with brilliant undulator x-ray beams at BL39XU and BL40XU, at the SPring-8, Harima, Japan. The emphasis is on the development of instruments to analyze a droplet of 0.1 μl containing trace elements of ppb level. Although the beamline is not a clean room, we have employed equipment for preparing a clean sample and also for avoiding contamination during transferring the sample into the spectrometer. We will report on the successful detection of the peak from 0.8 ppb selenium in a droplet (absolute amount 80 fg). We will also present the results of recent experiments obtained from a Johansson spectrometer rather than a Si(Li) detector. (author)

Ray-Tracing-Based Modeling of Clad-Removed Step-Index Plastic Optical Fiber in Smart Textiles: Effect of Curvature in Plain Weave Fabric

Directory of Open Access Journals (Sweden)

Sun Hee Moon

2018-01-01

Full Text Available Plastic optical fiber was chosen for information delivery media in smart textile. Cladding layer was peeled off by chemical and mechanical methods to find optimal peeling conditions. Both radial side illumination and longitudinal end-tip illumination were measured for visible light of 627 µm wavelength. A half-cone-shaped jig was manufactured using 3D printing to give various curvature conditions to fibers. Also POFs were embedded in plain weave textile structure to measure the light dissipation effect. The waveguide phenomenon was modeled using discrete ray tracing technique and ray-to-interface collision detection algorithm. Results from the proposed modeling technique showed linear relationship with those from experiment.

Trace rare earth analysis by neutron activation and γ-ray/x-ray spectrometry

International Nuclear Information System (INIS)

Laul, J.C.; Nielson, K.K.; Wogman, N.A.

1977-01-01

A rare earth group separation scheme followed by photon energy analysis using Ge(Li) and intrinsic Ge detectors enhances significantly the detection of individual rare earth elements (REE) at or below the ppb level. Based on the x-ray and selected γ-ray energies, Ge(Li) γ-ray counting is favorable for 140 La, 141 Ce, 142 Pr, 153 Sm, 171 Er, and 177 Lu, whereas intrinsic Ge γ-ray counting is favorable for 143 Ce, 147 Nd, 160 Tb, and 166 Ho, and intrinsic Ge x-ray counting is favorable for 152 Eu and 175 Yb. Gamma-ray counting of 153 Gd and 170 Tm is equally sensitive with Ge(Li) or intrinsic Ge detectors. Precise measurements of the REE were made in the USGS geological samples BCR-1, W-1, AGV-1, G2, GSP-1 and PCC-1, the IAEA Soil-5, and the NBS orchard leaf and bovine liver standards. Their chondritic normalized REE patterns behave as a smooth function of the REE ionic radii. Interestingly, the REE patterns observed in orchard leaf and other plants are identical to the REE pattern in bovine liver. This comparison leads us to suggest that the plant REE patterns are probably not further fractionated by animals such as bovine during their dietary plant uptake

Significant improvement of accuracy and precision in the determination of trace rare earths by fluorescence analysis

International Nuclear Information System (INIS)

Ozawa, L.; Hersh, H.N.

1976-01-01

Most of the rare earths in yttrium, gadolinium and lanthanum oxides emit characteristic fluorescent line spectra under irradiation with photons, electrons and x rays. The sensitivity and selectivity of the rare earth fluorescences are high enough to determine the trace amounts (0.01 to 100 ppM) of rare earths. The absolute fluorescent intensities of solids, however, are markedly affected by the synthesis procedure, level of contamination and crystal perfection, resulting in poor accuracy and low precision for the method (larger than 50 percent error). Special care in preparation of the samples is required to obtain good accuracy and precision. It is found that the accuracy and precision for the determination of trace (less than 10 ppM) rare earths by fluorescence analysis improved significantly, while still maintaining the sensitivity, when the determination is made by comparing the ratio of the fluorescent intensities of the trace rare earths to that of a deliberately added rare earth as reference. The variation in the absolute fluorescent intensity remains, but is compensated for by measuring the fluorescent line intensity ratio. Consequently, the determination of trace rare earths (with less than 3 percent error) is easily made by a photoluminescence technique in which the rare earths are excited directly by photons. Accuracy is still maintained when the absolute fluorescent intensity is reduced by 50 percent through contamination by Ni, Fe, Mn or Pb (about 100 ppM). Determination accuracy is also improved for fluorescence analysis by electron excitation and x-ray excitation. For some rare earths, however, accuracy by these techniques is reduced because indirect excitation mechanisms are involved. The excitation mechanisms and the interferences between rare earths are also reported

The capabilities of total reflection X-ray fluorescence in the polymeric analytical field

International Nuclear Information System (INIS)

Vazquez, Cristina

2004-01-01

This paper presents the capabilities of total reflection X-ray fluorescence (TXRF) as analytical technique specially focused in high-viscosity polymer dispersions. Appropriate sample preparation procedures are described taking into account the time stability of these dispersions. Special remarks considering different ways for drying samples in order to obtain the most uniform deposited film are investigated focusing on the behavior of aqueous and viscous systems. Due to the difficulty found for obtaining a homogeneous mixture between sample and internal standard in such systems, the use of Compton incoherent scattering is discussed as an alternative procedure for trace quantification in high viscous systems without any mixing processes

Simulation of transmitted X-rays in a polycapillary X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Peng, Shiqi [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Liu, Zhiguo, E-mail: liuzhiguo512@126.com [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi; Wang, Kai; Yi, Longtao; Yang, Kui; Chen, Man; Wang, Jinbang [The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-09-21

The geometrical description of capillary systems adjusted for the controlled guiding of X-rays and the basic theory of the transmission of X-rays are presented. A method of numerical calculation, based on Ray-Tracing theory, is developed to simulate the transmission efficiency of an X-ray parallel lens and the shape and size of the light spot gain from it. The simulation results for two half-lenses are in good agreement with the experimental results.

Trace elements in airborne particulates in South Africa

International Nuclear Information System (INIS)

Vleggaar, C.M.; Van As, D.; Watkins, J.L.; Mingay, D.W.; Wells, R.B.; Briggs, A.B.; Louw, C.W.

1980-10-01

Airborne particulate materials were monitored continously with calendar month sampling periods at 5 rural/background, 4 rural/developing/peri-urban, 6 urban and 7 industrial sites in South Africa. Concentrations of Al, Br, Ca, Cs, Cd, Cl, Co, Cr, Cu, Eu, Fe, K, Mg, Mn, Na, Ni, Pb, Rb, S, Sb, Sc, Se, Ti, V and Zn were determined with neutron activation analysis (NAA), atomic absorption spectroscopy (AAS) and particle-induced X-ray emission spectroscopy (PIXE) employed on a complementary basis. A review of sources of airborne trace elements is given. The monitoring program, sampling, sample-handling procedures, as well as the analytical methods used, are discussed in detail. The results of related studies, i.e. effects of filter materials; sampling rates and geometry; determinations of collection efficiencies; particle size ranges; effects of internal flux monitors on the precision and accuracy of NAA; trace impurities in blank materials; quality control by routine analysis of reference materials; comparison of results obtained by NAA, AAS, and PIXE analysis; are given, as is a review of air-pollution control and research policy in South Africa and of ambient air quality standards. Results are discussed in terms of general patterns in trace-element concentrations and enrichments, the general pattern in population centres, the variability of monthly concentrations, and in terms of long-term trends at background, rural, developing, peri-urban, urban and industrial sites. Cases of concern in respect of increasing concentrations are pointed out, as are the constantly high Pb levels at urban sites [af

Determination of heavy metals at traces level in leached samples by energy dispersive x-ray fluorescence technique

International Nuclear Information System (INIS)

Simabuco, Silvana M.; Nascimento Filho, Virgilio F. do; Inacio, Graziela R.; Navarro, Angela N.

1996-01-01

In landfill solid residues are disposed in the soil. When made based on technical criteria and specifically operation patterns a safe confinement is warranted according to environmental and public health protection. However, when the disposal is made by a random and unsuitable way serious problems can be caused as groundwater and superficial water contamination through leach action, indicating the usefulness of monitoring landfills. In this way energy dispersive X-ray fluorescence analysis with radioisotopic excitation was applied to evaluate the concentrations of heavy metals at trace levels in leached samples from the Americana City Landfill with pre-concentration of the elements by a non-specific precipitating agent, called ammonium pyrrolidine dithiocarbamate (APDC). (author)

Trace metal analysis by laser ablation-inductively coupled plasmamass spectrometry and x-ray K-edge densitometry of forensic samples

Energy Technology Data Exchange (ETDEWEB)

Berry, Jonna Elizabeth [Iowa State Univ., Ames, IA (United States)

2016-10-25

This dissertation describes a variety of studies on the determination of trace elements in samples with forensic importance. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine the trace element composition of numerous lipstick samples. Lipstick samples were determined to be homogeneous. Most lipstick samples of similar colors were readily distinguishable at a 95% confidence interval based on trace element composition. Numerous strands of a multi-strand speaker cable were analyzed by LA-ICP-MS. The strands in this study are spatially heterogeneous in trace element composition. In actual forensic applications, the possibility of spatial heterogeneity must be considered, especially in cases where only small samples (e.g., copper wire fragments after an explosion) are available. The effects of many unpredictable variables, such as weather, temperature, and human activity, on the retention of gunshot residue (GSR) around projectile wounds were assessed with LAICP- MS. Skin samples around gunshot and stab wounds and larvae feeding in and around the wounds on decomposing pig carcasses were analyzed for elements consistent with GSR (Sb, Pb, Ba, and Cu). These elements were detected at higher levels in skin and larvae samples around the gunshot wounds compared to the stab wounds for an extended period of time throughout decomposition in both a winter and summer study. After decomposition, radiographic images of the pig bones containing possible damage from bullets revealed metallic particles embedded within a number of bones. Metallic particles within the bones were analyzed with x-ray, K-edge densitometry and determined to contain lead, indicating that bullet residue can be retained throughout decomposition and detected within bones containing projectile trauma.

Some aspects of emission and volatization of trace elements on coal combustion

International Nuclear Information System (INIS)

Sanchez, J.C.D.; Formoso, M.L.L.; Bristoti, A.

1987-01-01

The present research work was carried out an industrial plant which uses a mixture of coals from Leao and Recreio mines for steam generation in a bioler with a capacity of 160t/h of steam. Coal samples from Leao, Recreio and the correspondent mixture were taken, as well as samples from the products of combustion. The present study fundamentally aims at assessing the emission of trace elements and major components of mineral matter, present in coal, in order to bring subsidies for a more efficient control over atmospheric, terrestrial and water pollution. Emissions of trace elements: As, B, Be, Cd, Cl, Co, Cr, Cu, F, Ga, Hg, Mn, Mo, Ni, Pb, S, Sn, V, Zn, Zr, and major elements: Si, Al, Ca, Mg, Ti, Fe, K and P, were calculated. Moreover, the average emission of particulate matter to the atmosphere was evaluated. In the present work, analytical procedures as X-ray spectroscopy and absorption spectroscopy and techniques used for the determination of F and Cl in Brazilian coals are cited. (author) [pt

Procedure for analyzing the x-ray line profiles of disordered carbons

International Nuclear Information System (INIS)

Henry, L.G.; Bragg, R.H.; Bose, S.

1981-12-01

A systematic procedure to correct for various distortions in the broad x-ray line profiles of glass-like carbons (GC) is described. The profile is first corrected for distortions due to low specimen absorption, secondly for incoherent (Compton) scattering, and then strong small angle scattering. The resulting profile is then multiplied by the appropriate trigonometric (Lorentz and polarization) factors. Finally, correction is made for the variation of the atomic scattering factor across the broad peaks. Two examples of the GC heat treatment at 1000 0 C and 2700 0 C have been used to illustrate the outcome of the corrections. 8 figures

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry.

Science.gov (United States)

Kaniu, M I; Angeyo, K H; Mwala, A K; Mangala, M J

2012-06-04

Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using (109)Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R(2)>0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g(-1) for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

The determination of trace quantities of thorium and uranium in thick ore samples by proton-induced x-ray emission

International Nuclear Information System (INIS)

Cohen, D.D.; Duerden, P.; Clayton, E.

1979-07-01

Proton-induced X-ray emission (PIXE) techniques have been used to estimate the concentrations of trace quantities of thorium and uranium in powdered rock and ore samples. Standards of known concentrations were prepared in a carbon matrix and the yields from these used to determine simultaneously the concentrations of thorium and uranium in the ore samples. The experimental detection limit of the technique was found to be 3 to 4 μg g -1 for a 100 μC irradiation. The appropriate matrix corrections for a carbon and ore matrix have been calculated for thick targets and taken into consideration

Determination of several trace elements in silicate rocks by an XRF method with background and matrix corrections

International Nuclear Information System (INIS)

Pascual, J.

1987-01-01

An X-ray fluorescence method for determining trace elements in silicate rock samples was studied. The procedure focused on the application of the pertinent matrix corrections. Either the Compton peak or the reciprocal of the mass absorption coefficient of the sample was used as internal standard for this purpose. X-ray tubes with W or Cr anodes were employed, and the W Lβ and Cr Kα Compton intensities scattered by the sample were measured. The mass absorption coefficients at both sides of the absorption edge for Fe (1.658 and 1.936 A) were calculated. The elements Zr, Y, Rb, Zn, Ni, Cr and V were determined in 15 international reference rocks covering wide ranges of concentration. Relative mean errors were in many cases less than 10%. (author)

The capabilities of total reflection X-ray fluorescence in the polymeric analytical field*1

Science.gov (United States)

Vázquez, Cristina

2004-08-01

This paper presents the capabilities of total reflection X-ray fluorescence (TXRF) as analytical technique specially focused in high-viscosity polymer dispersions. Appropriate sample preparation procedures are described taking into account the time stability of these dispersions. Special remarks considering different ways for drying samples in order to obtain the most uniform deposited film are investigated focusing on the behavior of aqueous and viscous systems. Due to the difficulty found for obtaining a homogeneous mixture between sample and internal standard in such systems, the use of Compton incoherent scattering is discussed as an alternative procedure for trace quantification in high viscous systems without any mixing processes.

Rapid fusion of 2D X-ray fluoroscopy with 3D multislice CT for image-guided electrophysiology procedures

Science.gov (United States)

Zagorchev, Lyubomir; Manzke, Robert; Cury, Ricardo; Reddy, Vivek Y.; Chan, Raymond C.

2007-03-01

Interventional cardiac electrophysiology (EP) procedures are typically performed under X-ray fluoroscopy for visualizing catheters and EP devices relative to other highly-attenuating structures such as the thoracic spine and ribs. These projections do not however contain information about soft-tissue anatomy and there is a recognized need for fusion of conventional fluoroscopy with pre-operatively acquired cardiac multislice computed tomography (MSCT) volumes. Rapid 2D-3D integration in this application would allow for real-time visualization of all catheters present within the thorax in relation to the cardiovascular anatomy visible in MSCT. We present a method for rapid fusion of 2D X-ray fluoroscopy with 3DMSCT that can facilitate EP mapping and interventional procedures by reducing the need for intra-operative contrast injections to visualize heart chambers and specialized systems to track catheters within the cardiovascular anatomy. We use hardware-accelerated ray-casting to compute digitally reconstructed radiographs (DRRs) from the MSCT volume and iteratively optimize the rigid-body pose of the volumetric data to maximize the similarity between the MSCT-derived DRR and the intra-operative X-ray projection data.

Radiation exposure of medical staff from interventional x-ray procedures: a multicentre study

International Nuclear Information System (INIS)

Haeusler, Uwe; Brix, Gunnar; Czarwinski, Renate

2009-01-01

The purpose of this study was to analyse the radiation exposure of medical staff from interventional x-ray procedures. Partial-body dose measurements were performed with thermoluminescent dosimeters (TLD) in 39 physicians and nine assistants conducting 73 interventional procedures of nine different types in 14 hospitals in Germany. Fluoroscopy time and the dose-area product (DAP) were recorded too. The median (maximum) equivalent body dose per procedure was 16 (2,500) μSv for an unshielded person; the partial-body dose per procedure was 2.8 (240) μSv to the eye lens, 4.1 (730) μSv to the thyroid, 44 (1,800) μSv to one of the feet and 75 (13,000) μSv to one of the hands. A weak correlation between fluoroscopy time or DAP and the mean TLD dose was observed. Generally, the doses were within an acceptable range from a radiation hygiene point of view. However, relatively high exposures were measured to the hand in some cases and could cause a partial-body dose above the annual dose limit of 500 mSv. Thus, the use of finger dosimeters is strongly recommended. (orig.)

Electroadsorption-assisted direct determination of trace arsenic without interference using transmission X-ray fluorescence spectroscopy.

Science.gov (United States)

Jiang, Tian-Jia; Guo, Zheng; Liu, Jin-Huai; Huang, Xing-Jiu

2015-08-18

An analytical technique based on electroadsorption and transmission X-ray fluorescence (XRF) for the quantitative determination of arsenic in aqueous solution with ppb-level limits of detection (LOD) is proposed. The approach uses electroadsorption to enhance the sensitivity and LOD of the arsenic XRF response. Amine-functionalized carbonaceous microspheres (NH2-CMSs) are found to be the ideal materials for both the quantitative adsorption of arsenic and XRF analysis due to the basic amine sites on the surface and their noninterference in the XRF spectrum. In electroadsorptive X-ray fluorescence (EA-XRF), arsenic is preconcentrated by a conventional three-electrode system with a positive electricity field around the adsorbents. Then, the quantification of arsenic on the adsorbents is achieved using XRF. The electroadsorption preconcentration can realize the fast transfer of arsenic from the solution to the adsorbents and improve the LOD of conventional XRF compared with directly determining arsenic solution by XRF alone. The sensitivity of 0.09 cnt ppb(-1) is obtained without the interferences from coexisted metal ions in the determination of arsenic, and the LOD is found to be 7 ppb, which is lower than the arsenic guideline value of 10 ppb given by the World Health Organization (WHO). These results demonstrated that XRF coupled with electroadsorption was able to determine trace arsenic in real water sample.

The use of synchrotron radiation for trace element analysis and element mapping by scanning X-ray fluorescence

International Nuclear Information System (INIS)

Davies, S.T.

1983-01-01

Synchrotron Radiation excited X-Ray Fluorescence is a potentially powerful tool for the routine quantitative chemical analysis of materials, with minimum detection limits typically of the order of a tenth of a ppm, and with the added advantages of simultaneous multi-element detection capability, spatial resolution on a micron scale, large signal to noise ratios and short analysis times. This paper presents a brief review of the use of Synchrotron Radiation in Trace Element Analysis and discusses the requirements for a microprobe for chemical analysis utilising SR. Data obtained at the Synchrotron Radiation Source, Daresbury Laboratory include XRF spectra of standard reference materials and an application of the technique to the study of ion implanted layers in semiconductors is outlined. (author)

Contribution of a 3D ray tracing model in a complex medium to the localization of infra-sound sources

International Nuclear Information System (INIS)

Mialle, Pierrick

2007-01-01

Localisation of infra-sound sources is a difficult task due to large propagation distances at stake and because of the atmospheric complexity. In order to resolve this problem, one can seek as many necessary information as the comprehension of wave propagation, the role and influence of the atmosphere and its spatio-temporal variations, the knowledge of sources and detection parameters, but also the configuration of the stations and their global spreading. Two methods based on the construction of propagation tables depending on station, date and time are introduced. Those tables require a long range propagation tool to simulate the propagation through a complex medium, which are carried out by WASP-3D Sph a 3D paraxial ray tracing based-theory tool integrating both amplitude estimation and horizontal wind fields in space and time. Tables are centered on the receptor. They describe spatial variations of the main observation parameters and offer a snapshot of the atmospheric propagation depending on the range for every simulated phase. For each path, celerity, azimuth deviation, attenuation and return altitude are predicted and allow building the tables. The latter help to identify detected phases and are integrated in an accurate localization procedure. The procedure is tested on three case study, such as the explosion of gas-pipeline in Belgium 2004 near Ghislenghien, the explosion of a military facility in 2007 in Novaky, Slovakia and the explosion of the Buncefield oil depot in 2005 in the United Kingdom, where event specificities, propagation parameters and used configurations are introduced. The accuracy and optimization of the localization are discussed. A validation study is presented regarding International Monitoring System stations along a meridian - I18DK (Greenland, Denmark), I51UK (Bermuda, United Kingdom), I25FR (Guyane, France), I08BO (La Paz, Bolivia), I01AR (Paso Flores, Argentina), I02AR (Ushuaia, Argentina), I54US (Antarctica, U.S.A.) - to

Confocal soft X-ray scanning transmission microscopy: setup, alignment procedure and limitations

International Nuclear Information System (INIS)

Späth, Andreas; Raabe, Jörg; Fink, Rainer H.

2015-01-01

A conventional STXM setup has been upgraded with a second micro zone plate and aligned to confocal geometry. Two confocal geometries (in-line and off-axis) have been evaluated and a discussion on prospects and limitations is presented. Zone-plate-based scanning transmission soft X-ray microspectroscopy (STXM) is a well established technique for high-contrast imaging of sufficiently transparent specimens (e.g. ultrathin biological tissues, polymer materials, archaeometric specimens or magnetic thin films) with spatial resolutions in the regime of 20 nm and high spectroscopic or chemical sensitivity. However, due to the relatively large depth of focus of zone plates, the resolution of STXM along the optical axis so far stays unambiguously behind for thicker X-ray transparent specimens. This challenge can be addressed by the implementation of a second zone plate in the detection pathway of the beam, resulting in a confocal arrangement. Within this paper a first proof-of-principle study for a confocal STXM (cSTXM) and an elaborate alignment procedure in transmission and fluorescence geometry are presented. Based on first confocal soft X-ray micrographs of well known specimens, the advantage and limitation of cSTXM as well as further development potentials for future applications are discussed

Confocal soft X-ray scanning transmission microscopy: setup, alignment procedure and limitations

Energy Technology Data Exchange (ETDEWEB)

Späth, Andreas [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany); Raabe, Jörg [Paul Scherrer Institut, 5232 Villigen (Switzerland); Fink, Rainer H., E-mail: rainer.fink@fau.de [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany); Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen (Germany)

2015-01-01

A conventional STXM setup has been upgraded with a second micro zone plate and aligned to confocal geometry. Two confocal geometries (in-line and off-axis) have been evaluated and a discussion on prospects and limitations is presented. Zone-plate-based scanning transmission soft X-ray microspectroscopy (STXM) is a well established technique for high-contrast imaging of sufficiently transparent specimens (e.g. ultrathin biological tissues, polymer materials, archaeometric specimens or magnetic thin films) with spatial resolutions in the regime of 20 nm and high spectroscopic or chemical sensitivity. However, due to the relatively large depth of focus of zone plates, the resolution of STXM along the optical axis so far stays unambiguously behind for thicker X-ray transparent specimens. This challenge can be addressed by the implementation of a second zone plate in the detection pathway of the beam, resulting in a confocal arrangement. Within this paper a first proof-of-principle study for a confocal STXM (cSTXM) and an elaborate alignment procedure in transmission and fluorescence geometry are presented. Based on first confocal soft X-ray micrographs of well known specimens, the advantage and limitation of cSTXM as well as further development potentials for future applications are discussed.

Two-dimensional micro-beam imaging of trace elements in a single plankton measured by a synchrotron radiation X-ray fluorescence analysis

International Nuclear Information System (INIS)

Ezoe, Masako; Sasaki, Miho; Hokura, Akiko; Nakai, Izumi; Terada, Yasuko; Yoshinaga, Tatsuki; Tukamoto, Katsumi; Hagiwara, Atsushi

2002-01-01

Two-dimensional imaging and a quantitative analysis of trace elements in rotifer, Brachionus plicatilis, belonging to zooplankton, were carried out by a synchrotron radiation X-ray fluorescence analysis (SR-XRF). The XRF imaging revealed that female rotifers accumulated Fe and Zn in the digestive organ and Fe, Zn, Cu, and Ca in the sexual organs, while the Mn level was high in the head. From a quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS), we found that rotifers eat the chlorella and accumulate the above elements in the body. The result of quantitative analyses of Mn, Cu, and Zn by SR-XRF in a single sample is in fair agreement with the average values determined by ICP-MS analyses, which were obtained by measuring a large number of rotifers, digested by nitric acid. The present study has demonstrated that SR-XRF is an effective tool for the trace element analysis of a single individual of rotifer. (author)

Two-dimensional micro-beam imaging of trace elements in a single plankton measured by a synchrotron radiation X-ray fluorescence analysis

Energy Technology Data Exchange (ETDEWEB)

Ezoe, Masako; Sasaki, Miho; Hokura, Akiko; Nakai, Izumi [Tokyo Univ. of Science, Faculty of Science, Tokyo (Japan); Terada, Yasuko [Japan Synchrotron Radiation Research Inst., Mikazuki, Hyogo (Japan); Yoshinaga, Tatsuki; Tukamoto, Katsumi [Tokyo Univ., Ocean Research Inst., Tokyo (Japan); Hagiwara, Atsushi [Nagasaki Univ., Graduate School of Science and Technology, Bunkyou, Nagasaki (Japan)

2002-10-01

Two-dimensional imaging and a quantitative analysis of trace elements in rotifer, Brachionus plicatilis, belonging to zooplankton, were carried out by a synchrotron radiation X-ray fluorescence analysis (SR-XRF). The XRF imaging revealed that female rotifers accumulated Fe and Zn in the digestive organ and Fe, Zn, Cu, and Ca in the sexual organs, while the Mn level was high in the head. From a quantitative analysis by inductively coupled plasma mass spectrometry (ICP-MS), we found that rotifers eat the chlorella and accumulate the above elements in the body. The result of quantitative analyses of Mn, Cu, and Zn by SR-XRF in a single sample is in fair agreement with the average values determined by ICP-MS analyses, which were obtained by measuring a large number of rotifers, digested by nitric acid. The present study has demonstrated that SR-XRF is an effective tool for the trace element analysis of a single individual of rotifer. (author)

Quantifying trace elements in individual aquatic protist cells with a synchrotron x-ray fluorescence microprobe

International Nuclear Information System (INIS)

Twining, B.S.; Baines, S.B.; Fisher, N.S.; Maser, J.; Vogt, S.; Jacobsen, C.; Tovar-Sanchez, A.; Sanudo-Wihelmy, S.A.

2003-01-01

The study of trace metal cycling by aquatic protists is limited by current analytical techniques. Standard 'bulk' element analysis techniques that rely on physical separations to concentrate cells for analysis cannot separate cells from co-occurring detrital material or other cells of differing taxonomy or trophic function. Here we demonstrate the ability of a synchrotron-based X-ray fluorescence (SXRF) microprobe to quantify the elements Si, Mn, Fe, Ni, and Zn in individual aquatic protist cells. This technique distinguishes between different types of cells in an assemblage and between cells and other particulate matter. Under typical operating conditions, the minimum detection limits are 7.0 x 10 -16 mol μm -2 for Si and between 5.0 x 10 -20 and 3.9 x 10 -19 mol μm -2 for Mn, Fe, Ni, and Zn; this sensitivity is sufficient to detect these elements in cells from even the most pristine waters as demonstrated in phytoplankton cells collected from remote areas of the Southern Ocean. Replicate analyses of single cells produced variations of <5% for Si, Mn, Fe, and Zn and <10% for Ni. Comparative analyses of cultured phytoplankton cells generally show no significant differences in cellular metal concentrations measured with SXRF and standard bulk techniques (spectrophotometry and graphite furnace atomic absorption spectrometry). SXRF also produces two-dimensional maps of element distributions in cells, thereby providing information not available with other analytical approaches. This technique enables the accurate and precise measurement of trace metals in individual aquatic protists collected from natural environments.

In-flight PSF calibration of the NuSTAR hard X-ray optics

DEFF Research Database (Denmark)

An, Hongjun; Madsen, Kristin K.; Westergaard, Niels J.

2014-01-01

We present results of the point spread function (PSF) calibration of the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR). Immediately post-launch, NuSTAR has observed bright point sources such as Cyg X-1, Vela X-1, and Her X-1 for the PSF calibration. We use the point source...... observations taken at several off-axis angles together with a ray-trace model to characterize the in-orbit angular response, and find that the ray-trace model alone does not fit the observed event distributions and applying empirical corrections to the ray-trace model improves the fit significantly. We...... describe the corrections applied to the ray-trace model and show that the uncertainties in the enclosed energy fraction (EEF) of the new PSF model is less than or similar to 3 for extraction apertures of R greater than or similar to 60" with no significant energy dependence. We also show that the PSF...

Calibration and correction procedures for cosmic-ray neutron soil moisture probes located across Australia

Science.gov (United States)

Hawdon, Aaron; McJannet, David; Wallace, Jim

2014-06-01

The cosmic-ray probe (CRP) provides continuous estimates of soil moisture over an area of ˜30 ha by counting fast neutrons produced from cosmic rays which are predominantly moderated by water molecules in the soil. This paper describes the setup, measurement correction procedures, and field calibration of CRPs at nine locations across Australia with contrasting soil type, climate, and land cover. These probes form the inaugural Australian CRP network, which is known as CosmOz. CRP measurements require neutron count rates to be corrected for effects of atmospheric pressure, water vapor pressure changes, and variations in incoming neutron intensity. We assess the magnitude and importance of these corrections and present standardized approaches for network-wide analysis. In particular, we present a new approach to correct for incoming neutron intensity variations and test its performance against existing procedures used in other studies. Our field calibration results indicate that a generalized calibration function for relating neutron counts to soil moisture is suitable for all soil types, with the possible exception of very sandy soils with low water content. Using multiple calibration data sets, we demonstrate that the generalized calibration function only applies after accounting for persistent sources of hydrogen in the soil profile. Finally, we demonstrate that by following standardized correction procedures and scaling neutron counting rates of all CRPs to a single reference location, differences in calibrations between sites are related to site biomass. This observation provides a means for estimating biomass at a given location or for deriving coefficients for the calibration function in the absence of field calibration data.

Trace element studies in bioenvironmental samples using 3-MeV protons

International Nuclear Information System (INIS)

Walter, R.L.; Willis, R.D.; Gutknecht, W.F.

1974-01-01

Trace metal compositions of a wide range of biological, environmental, medical and clinical samples were investigated using proton-induced x-ray emission analysis (PIXEA). The x-rays were detected with a Si(Li) detector and spectra from over 3000 irradiations have been recorded on magnetic tape. The chi 2 fitting code TRACE developed at our laboratory was used in a semi-automatic mode to extract abundances of elements from S to Cd. Various methods of overcoming analytical problems and specimen preparation difficulties are reported. Results from some samples for typical studies are illustrated along with the reasons for interest in the sample types

Particle induced X-ray emission and complementary nuclear methods for trace element determination; Plenary lecture

Energy Technology Data Exchange (ETDEWEB)

Johansson, S A.E. [Lund Univ. (Sweden). Dept. of Nuclear Physics

1992-03-01

In this review the state-of-the-art of particle induced X-ray emission (PIXE) methods for the determination of trace elements is described. The developmental work has mostly been carried out in nuclear physics laboratories, where accelerators are available, but now the increased interest has led to the establishment of other dedicated PIXE facilities. The reason for this interest is the versatility, high sensitivity and multi-element capability of PIXE analysis. A further very important advantage is that PIXE can be combined with the microbeam technique, which makes elemental mapping with a spatial resolution of about 1 {mu}m possible. As a technique, PIXE can also be combined with other nuclear reactions such as elastic scattering and particle-induced gamma emission, so that light elements can be determined. The usefulness of PIXE is illustrated by a number of typical applications in biology, medicine, geology, air pollution research, archaeology and the arts. (author).

Vapor phase treatment–total reflection X-ray fluorescence for trace elemental analysis of silicon wafer surface

International Nuclear Information System (INIS)

Takahara, Hikari; Mori, Yoshihiro; Shibata, Harumi; Shimazaki, Ayako; Shabani, Mohammad B.; Yamagami, Motoyuki; Yabumoto, Norikuni; Nishihagi, Kazuo; Gohshi, Yohichi

2013-01-01

Vapor phase treatment (VPT) was under investigation by the International Organization for Standardization/Technical Committee 201/Working Group 2 (ISO/TC201/WG2) to improve the detection limit of total reflection X-ray fluorescence spectroscopy (TXRF) for trace metal analysis of silicon wafers. Round robin test results have confirmed that TXRF intensity increased by VPT for intentional contamination with 5 × 10 9 and 5 × 10 10 atoms/cm 2 Fe and Ni. The magnification of intensity enhancement varied greatly (1.2–4.7 in VPT factor) among the participating laboratories, though reproducible results could be obtained for average of mapping measurement. SEM observation results showed that various features, sizes, and surface densities of particles formed on the wafer after VPT. The particle morphology seems to have some impact on the VPT efficiency. High resolution SEM observation revealed that a certain number of dots with SiO 2 , silicate and/or carbon gathered to form a particle and heavy metals, Ni and Fe in this study were segregated on it. The amount and shape of the residue should be important to control VPT factor. - Highlights: • This paper presents a summary of study results of VPT–TXRF using ISO/TC201/WG2. • Our goal is to analyze the trace metallic contamination on silicon wafer with concentrations below 1 × 10 10 atoms/cm 2 . • The efficiency and mechanism of VPT are discussed under several round robin tests and systematic studies

Wavefield extrapolation in caustic-free normal ray coordinates

KAUST Repository

Ma, Xuxin; Alkhalifah, Tariq Ali

2012-01-01

Normal ray coordinates are conventionally constructed from ray tracing, which inherently requires smooth velocity profiles. To use rays as coordinates, the velocities have to be smoothed further to avoid caustics, which is detrimental to the mapping

The applicability of physical optics in the millimetre and sub-millimetre spectral region. Part I: The ray tracing with diffraction on facets method

International Nuclear Information System (INIS)

Baran, A.J.; Hesse, Evelyn; Sourdeval, Odran

2017-01-01

Future satellite missions, from 2022 onwards, will obtain near-global measurements of cirrus at microwave and sub-millimetre frequencies. To realise the potential of these observations, fast and accurate light-scattering methods are required to calculate scattered millimetre and sub-millimetre intensities from complex ice crystals. Here, the applicability of the ray tracing with diffraction on facets method (RTDF) in predicting the bulk scalar optical properties and phase functions of randomly oriented hexagonal ice columns and hexagonal ice aggregates at millimetre frequencies is investigated. The applicability of RTDF is shown to be acceptable down to size parameters of about 18, between the frequencies of 243 and 874 GHz. It is demonstrated that RTDF is generally well within about 10% of T-matrix solutions obtained for the scalar optical properties assuming hexagonal ice columns. Moreover, on replacing electromagnetic scalar optical property solutions obtained for the hexagonal ice aggregate with the RTDF counterparts at size parameter values of about 18 or greater, the bulk scalar optical properties can be calculated to generally well within ±5% of an electromagnetic-based database. The RTDF-derived bulk scalar optical properties result in brightness temperature errors to generally within about ±4 K at 874 GHz. Differing microphysics assumptions can easily exceed such errors. Similar findings are found for the bulk scattering phase functions. This finding is owing to the scattering solutions being dominated by the processes of diffraction and reflection, both being well described by RTDF. The impact of centimetre-sized complex ice crystals on interpreting cirrus polarisation measurements at sub-millimetre frequencies is discussed. - Highlights: • A method of physical optics is shown to apply to size parameters as low as 18 in the mm and sub-mm-wave spectral regions. • Including ray tracing with diffraction on facets and diffraction at the cross-section of

Energy dispersion X-ray fluorescence techniques in water pollution analysis

International Nuclear Information System (INIS)

Holynska, B.

1980-01-01

Advantages and limitations of energy dispersion X-ray fluorescence methods for analysis of pollutants in water are discussed. The necessary equipment for X-ray measurement of insoluble and dissolved trace metals in water is described. Different techniques of enrichment of trace metals are presented: ion exchange on selective Chelex-100 exchanger, precipitation with chelating agents DDTC and APDC, and adsorption on activated carbon. Some results obtained using different preconcentration methods for trace metals determination in different waters are presented. (author)

Concentration distribution of trace elements: from normal distribution to Levy flights

International Nuclear Information System (INIS)

Kubala-Kukus, A.; Banas, D.; Braziewicz, J.; Majewska, U.; Pajek, M.

2003-01-01

The paper discusses a nature of concentration distributions of trace elements in biomedical samples, which were measured by using the X-ray fluorescence techniques (XRF, TXRF). Our earlier observation, that the lognormal distribution well describes the measured concentration distribution is explained here on a more general ground. Particularly, the role of random multiplicative process, which models the concentration distributions of trace elements in biomedical samples, is discussed in detail. It is demonstrated that the lognormal distribution, appearing when the multiplicative process is driven by normal distribution, can be generalized to the so-called log-stable distribution. Such distribution describes the random multiplicative process, which is driven, instead of normal distribution, by more general stable distribution, being known as the Levy flights. The presented ideas are exemplified by the results of the study of trace element concentration distributions in selected biomedical samples, obtained by using the conventional (XRF) and (TXRF) X-ray fluorescence methods. Particularly, the first observation of log-stable concentration distribution of trace elements is reported and discussed here in detail

A functional equation for the specular reflection of rays.

Science.gov (United States)

Le Bot, A

2002-10-01

This paper aims to generalize the "radiosity method" when applied to specular reflection. Within the field of thermics, the radiosity method is also called the "standard procedure." The integral equation for incident energy, which is usually derived for diffuse reflection, is replaced by a more appropriate functional equation. The latter is used to solve some specific problems and it is shown that all the classical features of specular reflection, for example, the existence of image sources, are embodied within this equation. This equation can be solved with the ray-tracing technique, despite the implemented mathematics being quite different. Several interesting features of the energy field are presented.

Using portable X-ray fluorescence spectrometry and GIS to assess environmental risk and identify sources of trace metals in soils of peri-urban areas in the Yangtze Delta region, China.

Science.gov (United States)

Ran, Jing; Wang, Dejian; Wang, Can; Zhang, Gang; Yao, Lipeng

2014-08-01

Portable X-ray fluorescence (PXRF) spectrometry may be very suitable for a fast and effective environmental assessment and source identification of trace metals in soils. In this study, topsoils (0-10 cm) at 139 sites were in situ scanned for total trace metals (Cr, Cu, Ni, Pb and Zn) and arsenic concentrations by PXRF in a typical town in Yangtze Delta region of Jiangsu province, China. To validate the utility of PXRF, 53 samples were collected from the scanning sites for the determination of selected trace metals using conventional methods. Based on trace metal concentrations detected by in situ PXRF, the contamination extent and sources of trace metals were studied via geo-accumulation index, multivariate analysis and geostatistics. The trace metal concentrations determined by PXRF were similar to those obtained via conventional chemical analysis. The median concentration of As, Cr, Cu, Ni, Pb and Zn in soils were 10.8, 56.4, 41.5, 43.5, 33.5, and 77.7 mg kg(-1), respectively. The distribution patterns of Cr, Cu, Ni, Pb, and Zn were mostly affected by anthropogenic sources, while As was mainly derived from lithogenic sources. Overall, PXRF has been successfully applied to contamination assessment and source identification of trace metals in soils.

Study of the effect of some of the experimental parameters on the x-ray fluorescence determination of traces of hafnia in high purity zirconia

International Nuclear Information System (INIS)

Qurbani, J.M.; Khanna, P.P.; Agrawal, R.M.

1974-01-01

The effect of the following parameters : (i) analytical lines HfLsub(αsub(1)) or HfLsub(βsub(1,6)) or HfLsub(βsub(2)) (ii) detectors - scintillation or gas flow proportional (iii) collimators - fine or coarse (iv) x-ray tube voltage, current and power (v) order of diffraction : I or II of analysing crystal LiF (200), on the precision of the results and the sensitivity of the method in the x-ray fluorescence determination of traces of hafnia in high purity zirconia, has been studied. Philips semiautomatic x-ray spectrometer PW 1220 with associated equipment has been used. Synthetic standards containing HfO 2 in the range 20 ppm to 1 % in ZrO 2 , presented as double layer pellets have been used. LiF (200) analysing crystal, tungsten target x-ray tube, automatic pulse height selection and pulse height discrimination were used in all the cases. The set - 'HfLsub(βsub(1,6)) analytical line, fine collimator and gas flow proportional counter detector' - gave the best performance. (author)

Robust ray-tracing algorithms for interactive dose rate evaluation

International Nuclear Information System (INIS)

Perrotte, L.

2011-01-01

More than ever, it is essential today to develop simulation tools to rapidly evaluate the dose rate received by operators working on nuclear sites. In order to easily study numerous different scenarios of intervention, computation times of available softwares have to be all lowered. This mainly implies to accelerate the geometrical computations needed for the dose rate evaluation. These computations consist in finding and sorting the whole list of intersections between a big 3D scene and multiple groups of 'radiative' rays meeting at the point where the dose has to be measured. In order to perform all these computations in less than a second, we first propose a GPU algorithm that enables the efficient management of one big group of coherent rays. Then we present a modification of this algorithm that guarantees the robustness of the ray-triangle intersection tests through the elimination of the precision issues due to floating-point arithmetic. This modification does not require the definition of scene-dependent coefficients ('epsilon' style) and only implies a small loss of performance (less than 10%). Finally we propose an efficient strategy to handle multiple ray groups (corresponding to multiple radiative objects) which use the previous results.Thanks to these improvements, we are able to perform an interactive and robust dose rate evaluation on big 3D scenes: all of the intersections (more than 13 million) between 700 000 triangles and 12 groups of 100 000 rays each are found, sorted along each ray and transferred to the CPU in 470 milliseconds. (author) [fr

X-ray imaging with toroidal mirror

International Nuclear Information System (INIS)

Aoki, Sadao; Sakayanagi, Yoshimi

1978-01-01

X-ray imaging is made with a single toroidal mirror or two successive toroidal mirrors. Geometrical images at the Gaussian image plane are described by the ray trace. Application of a single toroidal mirror to small-angle scattering is presented. (author)

X-ray optics and X-ray microscopes: new challenges

International Nuclear Information System (INIS)

Susini, J.

2004-01-01

Soon after the discovery of X-rays in 1895 by W. Roentgen, it became rapidly clear that the methods traditionally used in the visible light regime, namely refraction, diffraction and reflection were difficult to apply for X-ray optics. The physical origins of these difficulties are closely linked to the very nature of interaction of X-rays with matter. The small deviation δ of the refractive index of condensed matter from unity makes it difficult to extend refraction-based optics from the optical spectral region to the X-ray region because the refraction angle is proportional to δ. Similarly it is very challenging to extend diffraction-based focusing techniques to X-rays because the diffraction angle scales inversely with wavelength. Finally, the use of reflection-based optics is also limited by the very small critical angle for total reflection. All those fundamental limitations prevented for almost one century, the development of X-ray microscopy whereas electron microscopy became a standard tool. In the past twenty years, interests for X-ray microscopy revived, mainly because of several major advances in X-ray sources and X-ray optics. X-ray microscopy techniques are now emerging as powerful and complementary tools for submicron investigations. Soft X-ray microscopes offer traditionally the possibility to form direct images of thick hydrated biological material in near-native environment, at a spatial resolution well beyond that achievable with visible light microscopy. Natural contrast is available in the soft X-ray region, in the so-called ''water-window'', due to the presence of absorption edges of the major constituents (C,N,O). Recent advances in manufacturing techniques have enlarged the accessible energy range of micro-focussing optics and offer new applications in a broad range of disciplines. X-ray microscopy in the 1 - 30 keV energy range is better suited for fluorescence to map trace elements, tomography for 3D imaging and micro-diffraction. The

Photographic paper X-ray procedure - a simple technique for the visualisation of osseous norm variations and malformations

International Nuclear Information System (INIS)

Markert, K.; Wirth, I.; Reinhold-Richter, L.

1983-01-01

On the basis of osseous norm variations and malformations, a simple X-ray procedure by means of photographic paper which can be applied in every institute of pathology is demonstrated. The quality of the photographs permits the assessment of skeletal changes which are of diagnostic importance. (author)

ACTRIS Aerosol, Clouds and Trace Gases Research Infrastructure

OpenAIRE

Pappalardo Gelsomina

2018-01-01

The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS) is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evo...

The extended Beer-Lambert theory for ray tracing modeling of LED chip-scaled packaging application with multiple luminescence materials

Science.gov (United States)

Yuan, Cadmus C. A.

2015-12-01

Optical ray tracing modeling applied Beer-Lambert method in the single luminescence material system to model the white light pattern from blue LED light source. This paper extends such algorithm to a mixed multiple luminescence material system by introducing the equivalent excitation and emission spectrum of individual luminescence materials. The quantum efficiency numbers of individual material and self-absorption of the multiple luminescence material system are considered as well. By this combination, researchers are able to model the luminescence characteristics of LED chip-scaled packaging (CSP), which provides simple process steps and the freedom of the luminescence material geometrical dimension. The method will be first validated by the experimental results. Afterward, a further parametric investigation has been then conducted.

Proton exciting X ray analysis

International Nuclear Information System (INIS)

Ma Xinpei

1986-04-01

The analyzing capability of proton exciting X ray analysis for different elements in organisms was discussed, and dealing with examples of trace element analysis in the human body and animal organisms, such as blood serum, urine, and hair. The sensitivity, accuracy, and capability of multielement analysis were discussed. Its strong points for the trace element analysis in biomedicine were explained

Ray-tracing studies for a whole-viewing-angle retro-reflector

International Nuclear Information System (INIS)

Yang, B.; Friedsam, H.

1999-01-01

The APS Survey and Alignment team uses LEICA laser trackers for the majority of their alignment tasks. These instruments utilize several different retro-reflectors for tracking the path of the laser interferometer. Currently in use are open-air comer cubes with an acceptance angle of ±20 deg C, comer cube prisms with an acceptance angle of ±50 deg C, and a Cat's eye with an acceptance angle of ±60 deg C. Best measurement results can be achieved by using an open-air comer cube that eliminates the need for the laser beam to travel through a different medium before it returns to the instrument detector. However, the trade off is a small acceptance angle. In order to overcome the limitations of the small acceptance angles, Takatsuji et al. have proposed the creation of a full-viewing-angle retro-reflector. Based on the notion that the radius R 1 of a common Cat's eye is proportional to R 2 , one can write: R 1 = (n-1)R 2 In the case that n, the refractive index of glass, equals 2, the radii R 1 and R 2 are identical, and one can create a solid sphere Cat's eye. This design has the advantages that no adhesives are used to bond the two hemispheres together, misalignments between the hemispheres are not an issue, and most importantly, larger acceptance angles are possible. This paper shows the results of our ray tracing calculations characterizing the geometrical optics. In Section 2 we derived the analytical expressions for choosing the index of refraction n of a glass sphere based on the specifications of the reflected beam. We also provided an approximation for calculating the minimum radius of a reflector sphere based on efficiency considerations. Finally, in section 3, the analytically derived results were confirmed in a design study for a Cat's eye. (authors)

ACTRIS Aerosol, Clouds and Trace Gases Research Infrastructure

Science.gov (United States)

Pappalardo, Gelsomina

2018-04-01

The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS) is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evolution of the atmospheric environment.

Simulating polarized light scattering in terrestrial snow based on bicontinuous random medium and Monte Carlo ray tracing

International Nuclear Information System (INIS)

Xiong, Chuan; Shi, Jiancheng

2014-01-01

To date, the light scattering models of snow consider very little about the real snow microstructures. The ideal spherical or other single shaped particle assumptions in previous snow light scattering models can cause error in light scattering modeling of snow and further cause errors in remote sensing inversion algorithms. This paper tries to build up a snow polarized reflectance model based on bicontinuous medium, with which the real snow microstructure is considered. The accurate specific surface area of bicontinuous medium can be analytically derived. The polarized Monte Carlo ray tracing technique is applied to the computer generated bicontinuous medium. With proper algorithms, the snow surface albedo, bidirectional reflectance distribution function (BRDF) and polarized BRDF can be simulated. The validation of model predicted spectral albedo and bidirectional reflectance factor (BRF) using experiment data shows good results. The relationship between snow surface albedo and snow specific surface area (SSA) were predicted, and this relationship can be used for future improvement of snow specific surface area (SSA) inversion algorithms. The model predicted polarized reflectance is validated and proved accurate, which can be further applied in polarized remote sensing. -- Highlights: • Bicontinuous random medium were used for real snow microstructure modeling. • Photon tracing technique with polarization status tracking ability was applied. • SSA–albedo relationship of snow is close to that of sphere based medium. • Validation of albedo and BRDF showed good results. • Validation of polarized reflectance showed good agreement with experiment data

PIXE analysis of trace elements in relation to chlorophyll concentration in Plantago ovata Forsk

International Nuclear Information System (INIS)

Saha, Priyanka; Sen Raychaudhuri, Sarmistha; Chakraborty, Anindita; Sudarshan, Mathummal

2010-01-01

Plantago ovata Forsk - an economically important medicinal plant - was analyzed for trace elements and chlorophyll in a study of the effects of gamma radiation on physiological responses of the seedlings. Proton-induced X-ray emission (PIXE) technique was used to quantify trace elements in unirradiated and gamma-irradiated plants at the seedling stage. The experiments revealed radiation-induced changes in the trace element and chlorophyll concentrations.

Application of micro-PIXE to fish life history analyses: trace element analysis of otoliths

International Nuclear Information System (INIS)

Elfman, M.; Limburg, K.E.; Kristiansson, P.; Malmqvist, K.; Pallon, J.

1999-01-01

Otoliths are biogenic, carbonate concretions which form part of the hearing/balance system in fishes. The radial growth of otoliths and the variation of trace elements along the radius appear to capture important aspects of fishes' environmental history. At the Lund Nuclear Microprobe Laboratory, we have begun to use Proton-Induced X-ray Emission spectroscopy (PIXE) for micro-elemental analysis of otoliths. The experimental procedure is discussed and a number of examples of what can be investigated are presented. In particular, movement of diadromous species (eel, menhaden, and anadromous brown trout) can be detected between fresh and brackish water by Sr/Ca ratio. This technique has also been used to identify fish that were raised in freshwater hatcheries and then released to brackish water (pike-perch example)

Trace-element speciation and partitioning in environmental geochemistry and health

Energy Technology Data Exchange (ETDEWEB)

Farmer, J.G.; Gibson, M.J.; Lovell, M.A.

1983-09-01

Establishment of the chemical form and associations of trace elements is important in the scientifc and medical fields related to environmental geochemistry and health. Fundamental understanding of trace-element behavior, the realistic formulation of historical perspectives of trace-element contamination, an assessment of environmental transformation processes and a thorough appraisal of environment-related ill health and disease all depend on knowledge of the chemical speciation and partitioning of trace elements. These topics and the development of analytical speciation techniques and procedures are discussed with reference to trace-element studies in the Department of Forensic Medicine and Science, University of Glasgow, on lacustrine sediments and water, the atmosphere, soil and street dirt of an urban environment, and human biological fluids. 206 references, 4 figures.

Complex ray analysis for plasmas

International Nuclear Information System (INIS)

Connor, K.A.

1980-01-01

An extension of ray tracing techniques is considered for a variety of cases in which the dispersion relation of the plasma medium is complex. The ray trajectories are permitted to begin and/or at least travel through complex space-time; the wave propagation process so characterized becomes significant only where the rays intersect real space-time. It is found that rules and guidelines can be established for limited application of this idea

ACTRIS Aerosol, Clouds and Trace Gases Research Infrastructure

Directory of Open Access Journals (Sweden)

Pappalardo Gelsomina

2018-01-01

Full Text Available The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evolution of the atmospheric environment.

A multichannel magnetic β-ray spectrometer for rapid measurements of electron spectra

International Nuclear Information System (INIS)

Kariya, Komyo; Morikawa, Kaoru.

1989-01-01

In order to make the magnetic β-ray spectrometer suitable for rapid measurements of electron spectra with short-lived nuclides, twelve small GM counters have been arrayed along the focal plane of a 180deg focusing flat type design. All the signal pulses from each one of these detectors are mixed together onto a single cable. By means of multichannel PHA, each pulse can be traced back to the specific detector which sent it out. In order to avoid time consuming evacuation procedures, the sample source is placed outside a thin window of the preevacuated analyzer chamber. By the use of this multichannel spectrometer a β-ray spectrum with maximum energy up to about 10 MeV can be measured within 1 min or so. Electron spectra measured with 113m In, 119m In and 144 Pr source are shown. (author)

Theoretical simulation and analysis of large size BMP-LSC by 3D Monte Carlo ray tracing model

International Nuclear Information System (INIS)

Zhang Feng; Zhang Ning-Ning; Yan Sen; Song Sun; Jun Bao; Chen Gao; Zhang Yi

2017-01-01

Luminescent solar concentrators (LSC) can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic (PV) cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells (BMP-LSC) can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed. (paper)

Theoretical simulation and analysis of large size BMP-LSC by 3D Monte Carlo ray tracing model

Institute of Scientific and Technical Information of China (English)

Feng Zhang; Ning-Ning Zhang; Yi Zhang; Sen Yan; Song Sun; Jun Bao; Chen Gao

2017-01-01

Luminescent solar concentrators (LSC) can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic (PV) cells,and thereby reducing the cost of PV electricity generation.LSCs with bottom-facing cells (BMP-LSC) can collect both direct light and indirect light,so further improving the efficiency of the PV cells.However,it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC.In this paper,all the physical processes of the light transmission and collection in the BMP-LSC were analyzed.A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC.A larger-size LSC was simulated,and the effects of dye concentration,the LSC thickness,the cell area,and the cell distance were systematically analyzed.

Combining trace elements micro-analysis in deposited dredged sediments: EPMA and μ-XRF analysis

International Nuclear Information System (INIS)

Poitevin, A; Lerouge, C; Wille, G; Bataillard, P; Quinn, P; Hennet, L

2012-01-01

Since deposited dredged sediments are rich in metallic contaminants, they present a risk for environment. This work aims to study dredged sediments chemical composition, identify metal-carrier minerals and understand their mobility. Combining chemical and spectroscopic techniques at multi-scale for an integrative approach of trace elements (zinc, lead, iron) behaviour is therefore necessary. The global mineralogy and the chemistry of the sediment were determined by X-ray diffraction and fluorescence (XRF), respectively. Zn and Pb enriched fractions were separated using a sequential chemical extraction procedure and measured by inductively coupled plasma atomic emission and mass spectroscopy. Microanalyses using scanning electron microscopy (SEM), electron microprobe microanalysis (EPMA), combined with synchrotron radiation X-ray fluorescence (μ-XRF) were carried out to characterize mineralogical phases and identify Zn and Pb carrier minerals. Iron oxyhydroxides and iron sulphides were consistently identify as Zn and Pb carriers. The assumption that carbonate fraction was the major Zn carried phase, as demonstrated by chemical extraction results, was not verified by EPMA or μ-XRF.

Ray trace visualization of negative refraction of light in two-dimensional air-bridged silicon photonic crystal slabs at 1.55 microm.

Science.gov (United States)

Gan, Lin; Liu, Ya-Zhao; Li, Jiang-Yan; Zhang, Ze-Bo; Zhang, Dao-Zhong; Li, Zhi-Yuan

2009-06-08

We demonstrate design, fabrication, and ray trace observation of negative refraction of near-infrared light in a two-dimensional square lattice of air holes etched into an air-bridged silicon slab. Special surface morphologies are designed to reduce the impedance mismatch when light refracts from a homogeneous silicon slab into the photonic crystal slab. We clearly observed negative refraction of infrared light for TE-like modes in a broad wavelength range by using scanning near-field optical microscopy technology. The experimental results are in good agreement with finite-difference time-domain simulations. The results indicate the designed photonic crystal structure can serve as polarization beam splitter.

From trace chemistry to single atom chemistry

International Nuclear Information System (INIS)

Adloff, J.P.

1993-01-01

Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

PIXE determination of essential trace elements in some traditional Chinese medicines

International Nuclear Information System (INIS)

Xiao, L.; Qin, J.F.

1990-01-01

The essential trace elements in 30 traditional Chinese medicines, (24 tonics and 6 nontonics) were determined by proton-induced X-ray emission. The authors' previous suggestion that traditional Chinese medicines may be classified by the order of magnitude of their essential trace elements, thus indicating their pharmacological effects, is not justified. The pharmacological effect of a trace element or its essentiality may be dependent on some ligand that can be chelated with it. A nonlinear mapping algorithm, however, shows that the 30 traditional Chinese medicines are nearly separated into two groups, indicating their tonic or nontonic pharmacological effects

Trace element analysis in rheumatoid arthritis under chrysotherapy

International Nuclear Information System (INIS)

Lecomte, R.; Paradis, P.; Monaro, S.; Barrette, M.; Lamoureux, G.; Menard, H.A.

1981-01-01

Proton induced X-ray emission (PIXE) analysis is used to measure trace element concentrations in blood serum from patients with rheumatoid arthritis. Initially trace element contaminations in blood-collecting and storing devices are determined. Then mean values and nyctemeral cycles are measured both in normal subjects and patients with rheumatoid arthritis and other similar pathologies. Abnormal concentrations of Cu and Zn and anomalies in the nyctemeral cycle are found in the patients. In the second phase of the project, the special case of chrysotherapeutically treated (gold salt treatment) rheumatoid arthritis patients is studied for extended periods of time (up to 53 weeks). (orig.)

Trace element distribution in geological crystals

Energy Technology Data Exchange (ETDEWEB)

Den Besten, J.L.; Jamieson, D.N.; Weiser, P.S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1996-12-31

Channelling is a useful microprobe technique for determining the structure of crystals, but until now has not been performed on geological crystals. The composition has been investigated rather than the structure, which can further explain the origin of the crystal and provide useful information on the substitutionality of trace elements. This may then lead to applications of extraction of valuable metals and semiconductor electronics. Natural crystals of pyrite, FeS{sub 2}, which contains a substantial concentration of gold were channeled and examined to identify the channel axis orientation. Rutherford Backscattering (RBS) and Particle Induced X-Ray Emission (PIXE) spectra using MeV ions were obtained in the experiment to provide a comparison of lattice and non-lattice trace elements. 3 figs.

Trace element distribution in geological crystals

Energy Technology Data Exchange (ETDEWEB)

Den Besten, J L; Jamieson, D N; Weiser, P S [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1997-12-31

Channelling is a useful microprobe technique for determining the structure of crystals, but until now has not been performed on geological crystals. The composition has been investigated rather than the structure, which can further explain the origin of the crystal and provide useful information on the substitutionality of trace elements. This may then lead to applications of extraction of valuable metals and semiconductor electronics. Natural crystals of pyrite, FeS{sub 2}, which contains a substantial concentration of gold were channeled and examined to identify the channel axis orientation. Rutherford Backscattering (RBS) and Particle Induced X-Ray Emission (PIXE) spectra using MeV ions were obtained in the experiment to provide a comparison of lattice and non-lattice trace elements. 3 figs.

Towards modeling of random lasing in dye doped bio-organic based systems: ray-tracing and cellular automaton analysis

Science.gov (United States)

Mitus, A. C.; Stopa, P.; Zaklukiewicz, W.; Pawlik, G.; Mysliwiec, J.; Kajzar, F.; Rau, I.

2015-08-01

One of many photonic applications of biopolymers as functional materials is random lasing resulting from an incorporation of highly luminescent dyes into biopolymeric matrix, which leads to a random but coherent light scattering in amplifying medium. In spite of numerous theoretical and experimental studies the origin of the coherence is still not clear and various scenarios are discussed. In particular, inhomogeneity of biopolymeric layers can hypothetically promote the feedback in the scattering of the emitted light resulting in coherent and incoherent random lasing. In this paper we analyze the light scattering in a model system of scattering centers of circular shapes and various dimensions using ray-tracing techniques. In the second part, which has mostly a tutorial character, we present the approach to the study of random lasing using a cellular automaton model of Wiersma et al.

Determination of trace element and heavy metal in black tea and tea leaves using x-ray fluorescence

International Nuclear Information System (INIS)

Salih, Mohamed Abualgasim Abdalhakam

2016-08-01

The aim of this study was to provide information about the trace element and heavy metals concentrations in black tea and tea leaves. 23 different samples were collected from the Sudanese local market. The collected samples were characterized as the most common used items in Sudan. The concentration of trace and heavy elements were determined using x-ray fluorescence (X RF) technique. The standard reference materials (IAEA-V-10) and hay (powder) were used to evaluate the accuracy of the analytical result. The measured values were found in agreement with the certified values. The elements determined were K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pb, Br, Rb, and Sr. The average concentration of the elements is black tea were 2277.43, 7245.71, 1.11, 1025.29, 334.29, 6.88, 11.24, 9.47, 1.02, 7.08, 97.4 and 63.21 respectively while the average concentration of the elements in leaves tea were 2644.44, 8805.56, 1.02, 571.81, 295.44, 6.19, 10.69, 9.26, 0.91, 13.42, 63.03 and 67.14 respectively. The results showed an increase in the concentration of some elements such as calcium, chromium, manganese, iron, nickel, copper, zinc, bromine, rubidium and strontium (22500, 6.75, 48.9, 194, 4.37, 9,77, 24.9, 8.23, 7.79, 40,9) ppm respectively compared to certified values. Correlation between concentration of certain element and cluster analysis were preformed and the results compared with values of literature and the concentrations of some elements found to be similar.(Author)

Biological trace element measurements using synchrotron radiation

International Nuclear Information System (INIS)

Giauque, R.D.; Jaklevic, J.M.; Thompson, A.C.

1985-07-01

The feasibility of performing x-ray fluorescence trace element determinations at concentrations substantially below the ppM level for biological materials is demonstrated. Conditions for achieving optimum sensitivity were ascertained. Results achieved for five standard reference materials were, in most cases, in excellent agreement with listed values. Minimum detectable limits of 20 ppM were measured for most elements

Radiation dose to procedural personnel and patients from an X-ray volume imaging system

International Nuclear Information System (INIS)

Paul, Jijo; Mbalisike, Emmanuel C.; Vogl, Thomas J.

2013-01-01

To evaluate the radiation dose received by procedural personnel and patients from an X-ray volume imaging (XVI) system during interventional procedures. Forty patients were examined using catheter angiography (group A), digital subtraction angiography (group B) and cone-beam CT (CBCT, group C). Doses to procedural personnel (using thermo-luminescent dosimeters, TLDs) and patients were estimated. Image quality and lesion delineation were assessed using objective and subjective methods. Shapiro-Wilk, two-sided Student's t and Wilcoxon matched-pairs tests were used to test statistical significance. Doses (milligrays) measured in the hands and left knee of the interventionist were higher than those in an assistant physician (P < 0.05). Doses (dose-area product and skin entry dose) were lower in group A and higher in C compared with other groups; moreover, comparison among the groups were significant (all P = 0.0001). Subjective and objective lesion delineation showed significant results (all P < 0.05) among the tumour types considered. Image quality estimation showed the opposite results for objective and subjective analysis. More doses were obtained for hands of the procedural personnel compared to other anatomical regions measured. Catheter angiography showed lower dose compared with other imaging groups examined. Lesion delineation was clearly possible using CBCT. Objective and subjective analysis showed the opposite results regarding image quality because of higher noise levels and artefacts. (orig.)

Safety code 19: recommended safety procedures for the selection, installation and use of x-ray diffraction equipment

International Nuclear Information System (INIS)

1984-01-01

This document is one of a series of Safety Codes prepared by the Radiation Protection Bureau to set out requirements for the safe use of radiation emitting devices. The equipment and installation guidelines and safety procedures detailed in this Code are primarily for the instruction and guidance of persons employed in Federal Public Service Departments and Agencies, as well as those coming under the jurisdiction of the Canada Labour Code. This Safety Code is also intended to assist other users of X-ray diffraction equipment to select safe equipment and to install and use it so that the radiation hazard to the operator and other persons in its vicinity is negligible. It should be noted that facilities under provincial jurisdiction may be subject to requirements specified under provincial statutes. This Code supersedes Safety Code RPD-SC-7, entitled 'Requirements For Non-Medical X-Ray Equipment, Use and Installation', insofar as X-ray diffraction equipment is concerned, and it is intended to complement X-ray equipment design, construction and performance standards promulgated under the Radiation Emitting Devices Act

Log-stable concentration distributions of trace elements in biomedical samples

International Nuclear Information System (INIS)

Kubala-Kukus, A.; Kuternoga, E.; Braziewicz, J.; Pajek, M.

2004-01-01

In the present paper, which follows our earlier observation that the asymmetric and long-tailed concentration distributions of trace elements in biomedical samples, measured by the X-ray fluorescence techniques, can be modeled by the log-stable distributions, further specific aspects of this observation are discussed. First, we demonstrate that, typically, for a quite substantial fraction (10-20%) of trace elements studied in different kinds of biomedical samples, the measured concentration distributions are described in fact by the 'symmetric' log-stable distributions, i.e. the asymmetric distributions which are described by the symmetric stable distributions. This observation is, in fact, expected for the random multiplicative process, which models the concentration distributions of trace elements in the biomedical samples. The log-stable nature of concentration distribution of trace elements results in several problems of statistical nature, which have to be addressed in XRF data analysis practice. Consequently, in the present paper, the following problems, namely (i) the estimation of parameters for stable distributions and (ii) the testing of the log-stable nature of the concentration distribution by using the Anderson-Darling (A 2 ) test, especially for symmetric stable distributions, are discussed in detail. In particular, the maximum likelihood estimation and Monte Carlo simulation techniques were used, respectively, for estimation of stable distribution parameters and calculation of the critical values for the Anderson-Darling test. The discussed ideas are exemplified by the results of the study of trace element concentration distributions in selected biomedical samples, which were obtained by using the X-ray fluorescence (XRF, TXRF) methods

Multichannel, sequential or combined X-ray spectrometry

International Nuclear Information System (INIS)

Florestan, J.

1979-01-01

X-ray spectrometer qualities and defects are evaluated for sequential and multichannel categories. Multichannel X-ray spectrometer has time-coherency advantage and its results could be more reproducible; on the other hand some spatial incoherency limits low percentage and traces applications, specially when backgrounds are very variable. In this last case, sequential X-ray spectrometer would find again great usefulness [fr

Application of micro-PIXE analysis to investigate trace elements in deciduous teeth enamel

International Nuclear Information System (INIS)

Igari, K.; Takahashi, A.; Ando, H.

2010-01-01

The early life environment has widespread consequences for later health and disease. To prevent the disease in later life, the assessment of fetal environment is very important. In Japan, birthweight has fallen rapidly during recent two decades. The reduction of birthweight represents reduced fetal nutrition. Deciduous tooth enamel contains pre- and postnatal enamel and its chemical composition reflects the status of metabolism of trace elements during formation period. Deciduous tooth enamel is considered to be a suitable indicator of trace elements exposure in utero. We applied micro-PIXE analysis to investigate the trace elemental content in deciduous tooth enamel. Two deciduous canines from one healthy Japanese boy were used for this study. The enamel section including pre- and postnatal enamel was prepared for micro-PIXE analysis. Five trace elements (Na, Mg, Cl, Zn, and Sr) were detected in the scanning area of tooth. The distribution profiles of 5 elements were obtained as X-ray maps. The distribution profiles of zinc and chlorine were specific, and showed higher concentration in surface enamel. No elements showed different profiles of X-ray maps between pre- and postnatal enamel in this sample. The results of this study suggested that micro-PIXE analysis would be able to estimate the trace elements in prenatal and postnatal enamel, respectively. (author)

Trace-Element Analysis by Use of PIXE Technique on Agricultural Products

Science.gov (United States)

Takagi, A.; Yokoyama, R.; Makisaka, K.; Kisamori, K.; Kuwada, Y.; Nishimura, D.; Matsumiya, R.; Fujita, Y.; Mihara, M.; Matsuta, K.; Fukuda, M.

2009-10-01

In order to examine whether a trace-element analysis by PIXE (Particle Induced X-ray Emission) gives a clue to identify production area of agricultural products, we carried out a study on soy beans as an example. In the present study, a proton beam at the energy of 2.3MeV was provided by Van de Graaff accelerator at Osaka University. We used a Ge detector with Be window to measure X-ray spectra. We prepared sample soy beans from China, Thailand, Taiwan, and 7 different areas in Japan. As a result of PIXE analysis, 5 elements, potassium, iron, zinc, arsenic and rubidium, have been identified. There are clear differences in relative amount of trace-elements between samples from different international regions. Chinese beans contain much more Rb than the others, while there are significant differences in Fe and Zn between beans of Thailand and Taiwan. There are relatively smaller differences among Japanese beans. This result shows that trace-elements bring us some practical information of the region where the product grown.

An improved ring removal procedure for in-line x-ray phase contrast tomography

Science.gov (United States)

Massimi, Lorenzo; Brun, Francesco; Fratini, Michela; Bukreeva, Inna; Cedola, Alessia

2018-02-01

The suppression of ring artifacts in x-ray computed tomography (CT) is a required step in practical applications; it can be addressed by introducing refined digital low pass filters within the reconstruction process. However, these filters may introduce additional ringing artifacts when simultaneously imaging pure phase objects and elements having a non-negligible absorption coefficient. Ringing originates at sharp interfaces, due to the truncation of spatial high frequencies, and severely affects qualitative and quantitative analysis of the reconstructed slices. In this work, we discuss the causes of ringing artifacts, and present a general compensation procedure to account for it. The proposed procedure has been tested with CT datasets of the mouse central nervous system acquired at different synchrotron radiation facilities. The results demonstrate that the proposed method compensates for ringing artifacts induced by low pass ring removal filters. The effectiveness of the ring suppression filters is not altered; the proposed method can thus be considered as a framework to improve the ring removal step, regardless of the specific filter adopted or the imaged sample.

Modelling of waves propagation on irregular surfaces using ray tracing and GTD approaches: Application to head waves simulation in TOFD inspections for NDT

Science.gov (United States)

Ferrand, Adrien; Darmon, Michel; Chatillon, Sylvain; Deschamps, Marc

2014-04-01

The Time of Flight Diffraction (TOFD) technique is a classical ultrasonic method used in ultrasonic non-destructive evaluation, which allows a precise positioning and a quantitative size evaluation of cracks in the inspected material. Among the typical phenomena arising in the current TOFD inspection, the so-called "head wave" is the first contribution reaching the receiver. The head wave propagation on a planar interface is well known and identified as a critical refraction taking place on the material surface. On irregular surfaces, it has been shown that the head wave results from the melting of surface and bulk waves mechanisms and that surface irregularities are responsible for numerous diffractions of the incident head wave. To simulate such behaviour, a model has been developed using a ray tracing technique based on time of flight minimization (generalized Fermat's principle). It enables the calculation of the ray path and the corresponding time of flight of all waves propagating in the material, including the head wave. To obtain a complete propagation model for these waves (both trajectory and amplitude), the integration of Geometrical Theory of Diffraction (GTD) models is currently performed by coupling them with the ray-based approach discussed above.

In vivo x-ray fluorescence of lead and other toxic trace elements

International Nuclear Information System (INIS)

Chettle, D.R.

1995-01-01

The first in vivo x-ray fluorescence measurements of lead in bone used y-rays from a 57 Co source to excite Pb K x-rays. Later systems used γ-rays from 109 Cd to excite Pb K x-rays or polarized x-rays to excite Ph L x-rays. All three approaches involve an extremely low effective dose to the subject. Of the two K x-ray techniques, 109 Cd is more precise and more flexible in choice of measurement site. Pb L x-ray fluorescence (L-XRF) effectively samples lead at bone surfaces, whereas Ph K x-ray fluorescence (K-XRF) samples through the bulk of a bone. Both the polarized L-XRF and 109 Cd K-XRF achieve similar precision. Renal mercury has recently been determined using a polarized x-ray source, Both renal and hepatic cadmium can be measured using polarized x-rays in conjunction with a Si(Li) detector. Platinum and gold have been measured both by radioisotopic source excitation and by using polarized x-rays, but the latter is to be preferred. Applications of Pb K-XRF have shown that measured bone lead relates strongly to cumulative lead exposure. Secondly, biological half lives of lead in different bone types have been estimated from limited longitudinal data sets and from some cross sectional surveys. Thirdly, the effect of bone lead as an endogenous source of lead has been demonstrated and it has been shown that a majority of circulating blood lead can be mobilized from bone, rather than deriving from new exposure, in some retired lead workers. 35 refs., 5 tabs

Spectrophotometric determination of trace uranium in phosphate ore samples from kurum and uro areas, Nuba mountains, Sudan

International Nuclear Information System (INIS)

Mohamed, A. A.; Ali, A. H.; Altayeb, M. A. H.

2004-01-01

A method was proposed for the spectrophotometric determination of uranium content in phosphate ores. the method is based on the use of nitrogen (v) acid for leaching the rock, and treatment with ammonium carbonate solution, whereby uranium (Vi) is kept in solution as its carbonate complex. The ion-exchange technique was used for the recovery of uranium. Uranium was determined spectrophotometrically by measurement of the absorbance of the yellow uranium (Vi)-8-hydroxyquinolate complex at λ 425 nm. The procedure was used for the determination of trace uranium content in 30 phosphate ore samples collected from Kurun and Uro areas in Nuba mountains in Sudan. X-ray fluorescence technique was employed for the assessment of the method used. The spectrophotometric method results show a high similarity with those obtained by XRF technique. This agreement indicates that the procedure proposed here has been successfully applied for the determination of uranium in phosphate ores. (Author)

Ray-tracing traveltime tomography versus wave-equation traveltime inversion for near-surface seismic land data

KAUST Repository

Fu, Lei

2017-05-11

Full-waveform inversion of land seismic data tends to get stuck in a local minimum associated with the waveform misfit function. This problem can be partly mitigated by using an initial velocity model that is close to the true velocity model. This initial starting model can be obtained by inverting traveltimes with ray-tracing traveltime tomography (RT) or wave-equation traveltime (WT) inversion. We have found that WT can provide a more accurate tomogram than RT by inverting the first-arrival traveltimes, and empirical tests suggest that RT is more sensitive to the additive noise in the input data than WT. We present two examples of applying WT and RT to land seismic data acquired in western Saudi Arabia. One of the seismic experiments investigated the water-table depth, and the other one attempted to detect the location of a buried fault. The seismic land data were inverted by WT and RT to generate the P-velocity tomograms, from which we can clearly identify the water table depth along the seismic survey line in the first example and the fault location in the second example.

Improving LED CCT uniformity using micropatterned films optimized by combining ray tracing and FDTD methods.

Science.gov (United States)

Ding, Xinrui; Li, Jiasheng; Chen, Qiu; Tang, Yong; Li, Zongtao; Yu, Binhai

2015-02-09

Although the light-emitting diode (LED) has revolutionized lighting, the non-uniformity of its correlated color temperature (CCT) still remains a major concern. In this context, to improve the light distribution performance of remote phosphor LED lamps, we employ a micropatterned array (MPA) optical film fabricated using a low-cost molding process. The parameters of the MPA, including different installation configurations, positioning, and diameters, are optimized by combining the finite-difference time-domain and ray-tracing methods. Results show that the sample with the upward-facing convex-cone MPA film that has a diameter of half of that of the remote phosphor glass, and is tightly affixed to the inward surface of the remote phosphor glass renders a superior light distribution performance. When compared with the case in which no MPA film is used, the deviation of the CCT distribution decreases from 1033 K to 223 K, and the corresponding output power of the sample is an acceptable level of 85.6%. We perform experiments to verify our simulation results, and the two sets of results exhibit a close agreement. We believe that our approach can be used to optimize MPA films for various lighting applications.

Modeling the reflectance of the lunar regolith by a new method combining Monte Carlo Ray tracing and Hapke's model with application to Chang'E-1 IIM data.

Science.gov (United States)

Wong, Un-Hong; Wu, Yunzhao; Wong, Hon-Cheng; Liang, Yanyan; Tang, Zesheng

2014-01-01

In this paper, we model the reflectance of the lunar regolith by a new method combining Monte Carlo ray tracing and Hapke's model. The existing modeling methods exploit either a radiative transfer model or a geometric optical model. However, the measured data from an Interference Imaging spectrometer (IIM) on an orbiter were affected not only by the composition of minerals but also by the environmental factors. These factors cannot be well addressed by a single model alone. Our method implemented Monte Carlo ray tracing for simulating the large-scale effects such as the reflection of topography of the lunar soil and Hapke's model for calculating the reflection intensity of the internal scattering effects of particles of the lunar soil. Therefore, both the large-scale and microscale effects are considered in our method, providing a more accurate modeling of the reflectance of the lunar regolith. Simulation results using the Lunar Soil Characterization Consortium (LSCC) data and Chang'E-1 elevation map show that our method is effective and useful. We have also applied our method to Chang'E-1 IIM data for removing the influence of lunar topography to the reflectance of the lunar soil and to generate more realistic visualizations of the lunar surface.

X-ray fluorescent analysis of iodin traces in urine

International Nuclear Information System (INIS)

Mikhajlov, I.F.; Baturin, A.A.; Mikhajlov, A.I.; Borisova, S.S.; Reshetnyak, M.V.; Shlyakhova, N.V.; Budrejko, E.A.; Galata, D.I.

2015-01-01

Using XFA method, determination of iodine concentration in urine for 35 children of 10-15 with endocrine pathology (delay of sexual development, diffuse goiter, obesity) and 10 practically healthy children being observed under conditions of the consultative polyclinic and the department of endocrinology of SI ''ISHCJ NAMSU''. The proposed optimized XFA method allows by 1-2 orders increasing detection sensitivity for micro-elements measurements in biology objects and attaining the iodine trace contents in urine in the range from 50 to 200 gg/dm 3

Epidemic contact tracing via communication traces.

Directory of Open Access Journals (Sweden)

Katayoun Farrahi

Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

Epidemic contact tracing via communication traces.

Science.gov (United States)

Farrahi, Katayoun; Emonet, Rémi; Cebrian, Manuel

2014-01-01

Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

The Medical Exposure to Ionizing Radiation and Protection of the Patient in Medical Imaging Procedures for Diagnostic and Therapeutic Purposes (Excluding Radiotherapy) using X-Rays in Israel - Risk - Cost and Benefit

International Nuclear Information System (INIS)

Ben-Shlomo, A.

1998-10-01

Diagnostic and therapeutic radiology is playing a major role in modern medicine. The utilization of devices emitting ionizing radiation for medical diagnostic and therapeutic purposes is classified into three categories: a. Radiotherapy procedures for the treatment of malignant and benign tumors. b. Nuclear medicine procedures using radiopharmaceuticals that are introduced into the patient's body for diagnostic and therapeutic purposes. c. Diagnostic and therapeutic x-ray imaging procedures. This group includes conventional radiography, conventional fluoroscopy, cardiac catheterization, angiography, CT, mammography, dental, and fluoroscopy operation procedures. A survey was carried out on a sample of three major Israeli hospitals in order to: 1. Determine the status of radiation protection of patients in Israel with regard to the use of x-rays in medical imaging and interventional radiology. 2. Assess the extent of exposure of the population to medical x-rays, and assess the collective risk in Israel in this relation (based on Icr-60). 3. Carry out a cost-benefit optimization procedure related to the means that should be used to reduce the exposure of Israeli patients under x-ray procedures. 4. Establish a of practical recommendations to reduce the x-ray radiation exposure of patients and to increase the image quality. 5. Establish a number of basic rules to be utilized by health policy makers in Israel

The Medical Exposure to Ionizing Radiation and Protection of the Patient in Medical Imaging Procedures for Diagnostic and Therapeutic Purposes (Excluding Radiotherapy) using X-Rays in Israel - Risk - Cost and Benefit

Energy Technology Data Exchange (ETDEWEB)

Ben-Shlomo, A

1998-10-01

Diagnostic and therapeutic radiology is playing a major role in modern medicine. The utilization of devices emitting ionizing radiation for medical diagnostic and therapeutic purposes is classified into three categories: a. Radiotherapy procedures for the treatment of malignant and benign tumors. b. Nuclear medicine procedures using radiopharmaceuticals that are introduced into the patient's body for diagnostic and therapeutic purposes. c. Diagnostic and therapeutic x-ray imaging procedures. This group includes conventional radiography, conventional fluoroscopy, cardiac catheterization, angiography, CT, mammography, dental, and fluoroscopy operation procedures. A survey was carried out on a sample of three major Israeli hospitals in order to: 1. Determine the status of radiation protection of patients in Israel with regard to the use of x-rays in medical imaging and interventional radiology. 2. Assess the extent of exposure of the population to medical x-rays, and assess the collective risk in Israel in this relation (based on Icr-60). 3. Carry out a cost-benefit optimization procedure related to the means that should be used to reduce the exposure of Israeli patients under x-ray procedures. 4. Establish a of practical recommendations to reduce the x-ray radiation exposure of patients and to increase the image quality. 5. Establish a number of basic rules to be utilized by health policy makers in Israel.

Survey of effective doses to patients undergoing contrast-based X-ray fluoroscopy procedures in Tanzania

International Nuclear Information System (INIS)

Ngaile, J.E.; Msaki, P.K.; Kazema, R.R.

2017-01-01

The aim of this study was to assess the radiation burden imparted to patients from contrast-based X-ray fluoroscopy procedures in Tanzania. The effective doses (EDs) to patients from five contrast-based fluoroscopy procedures were obtained from four hospitals. The ED was estimated using the knowledge of the patient characteristics, patient-related exposure parameters, measurements of air kerma area product and PCXCM software. The median EDs for the barium swallow (BS), barium meal (BM), barium enema (BE), hysterosalpingography (HSG) and retrograde urethrography (RUG) were 0.50, 1.43, 2.83, 0.65 and 0.59 mSv, respectively. The median ED per hospital for the BS and BM procedures varied by factors of up to 9.9 and 4.2, respectively, while for the BE, HSG and RUG varied by factors of up to 2.3, 2.4 and 4.3, respectively. The overall differences between individual EDs across the four hospitals varied by factors of up to 53, 58.9 and 11.4 for the BS, BM and BE, respectively, while for the HSG and RUG differed by factors of up to 22 and 46.7, respectively. The mean EDs in this study were mostly lower than reported values from Spain, the UK, Ghana and Greece, while slightly higher than those reported from India. The observed wide variations of procedural protocols and patient doses within and across the hospitals; and the observed high patient doses in this study relative to those from the literature call for the need to standardize procedural protocols and optimize contrast-based fluoroscopy procedures. (authors)

Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic Sediments Using Ray-Trace Inversion of First-Arrival Seismic Data and Elastic Finite-Difference Full-Wave Modeling Along Sinor-Valod Profile of Deccan Syneclise, India

Science.gov (United States)

Talukdar, Karabi; Behera, Laxmidhar

2018-03-01

Imaging below the basalt for hydrocarbon exploration is a global problem because of poor penetration and significant loss of seismic energy due to scattering, attenuation, absorption and mode-conversion when the seismic waves encounter a highly heterogeneous and rugose basalt layer. The conventional (short offset) seismic data acquisition, processing and modeling techniques adopted by the oil industry generally fails to image hydrocarbon-bearing sub-trappean Mesozoic sediments hidden below the basalt and is considered as a serious problem for hydrocarbon exploration in the world. To overcome this difficulty of sub-basalt imaging, we have generated dense synthetic seismic data with the help of elastic finite-difference full-wave modeling using staggered-grid scheme for the model derived from ray-trace inversion using sparse wide-angle seismic data acquired along Sinor-Valod profile in the Deccan Volcanic Province of India. The full-wave synthetic seismic data generated have been processed and imaged using conventional seismic data processing technique with Kirchhoff pre-stack time and depth migrations. The seismic image obtained correlates with all the structural features of the model obtained through ray-trace inversion of wide-angle seismic data, validating the effectiveness of robust elastic finite-difference full-wave modeling approach for imaging below thick basalts. Using the full-wave modeling also allows us to decipher small-scale heterogeneities imposed in the model as a measure of the rugose basalt interfaces, which could not be dealt with ray-trace inversion. Furthermore, we were able to accurately image thin low-velocity hydrocarbon-bearing Mesozoic sediments sandwiched between and hidden below two thick sequences of high-velocity basalt layers lying above the basement.

The use of chelating ion exchanger in conjunction with radioisotope X-ray spectrometry for determination of trace amounts of metals in water

International Nuclear Information System (INIS)

Holynska, B.

1974-01-01

The chelating ion exchange resin Chelex-100 has been applied for collection of trace amounts of several metal ions from water solutions. The kinetics of the exchange reaction has been measured, as well as the influence of pH of the solution and Ca or Na ion concentrations on the metal collection. The radioisotope X-ray fluorescence method has been applied for determination of metal ions absorbed in the resin. The estimated limit of determination is 0.01 ppm for Fe 3+ , Zn 2+ , Cu 2+ , Hg 2+ , Pb 2+ and Cd 2+ . Total error (1 s) of the method varied from 3 to 15% depending on the metal concentration. (author)

Ray-based stochastic inversion of prestack seismic data for improved reservoir characterization

NARCIS (Netherlands)

Van der Burg, D.; Verdel, A.; Wapenaar, C.P.A.

2009-01-01

Trace inversion for reservoir parameters is affected by angle averaging of seismic data and wavelet distortion on the migration image. In an alternative approach to stochastic trace inversion, the data are inverted prestack before migration using 3D dynamic ray tracing. This choice makes it possible

Multivariate cluster analysis of some major and trace elements ...

African Journals Online (AJOL)

UFUOMA

The chemical composition of water infiltrating ... Major and trace metals determined in soil and water from a ... The soil samples were air-dried at 29°C in a dust-free place for ... compact 3K5 X-ray generator (Ital IS Structures, Italy) was used for.

Application of Factorial Designs and Simplex Optimisation in the Development of Flow Injection-Hydride Generation-Graphite Furnace Atomic Absorption Spectrometry Procedures as Demonstrated for the Determination of Trace Levels of Germanium

DEFF Research Database (Denmark)

Hilligsøe, Bo; Hansen, Elo Harald

1997-01-01

The optimisation of a volume-based FI-HG-GFAAS procedure is described for the trace determination of Ge, comprising in situ collection of the generated germane in the graphite furnace. The response function is the peak area readout (A*s). Based on a preliminary study, where factorial designs were...

Hybrid Model For Reverberant Indoor Radio Channels Using Rays and Graphs

DEFF Research Database (Denmark)

Steinböck, Gerhard; Gan, Mingming; Meissner, Paul

2016-01-01

efficient calculation of the channel transfer function considering infinitely many components. We use ray-tracing and the theory of room electromagnetics to obtain the parameter settings for the propagation graph. Thus the proposed hybrid model does not require new or additional parameters in comparison...... to ray-tracing. Simulation results show good agreement with measurements with respect to the inclusion of the diffuse tail in both the delay power spectrum and the azimuth delay power spectrum....

Practical using of TXRF spectrometers with slitless collimators for the trace analysis of targets surfaces

International Nuclear Information System (INIS)

Egorov, V.K.; Zuev, A.P.; Kondratiev, O.S.; Egorov, E.V.

2000-01-01

TXRF spectrometer with the slitless collimator used for a formation of the x-ray excitating beam (TXRF-SC spectrometer) is a new variety of an instrument been destined for the trace analysis of surfaces by x-ray fluorescence method at the total reflection of the x-ray incident beam. Some theoretical concepts are introduced for a characterization of the x-ray optics been unique to the TXRF-SC spectrometer. The principle design of the TXRF-SC spectrometer used for the trace quantitative analysis of a surface are discussed. Spectra of a secondary x-ray radiation yield for typical targets been collected by using of the TXRF-SC spectrometer and calculation of surface trace elements concentrations are presented. The analytical and operating parameters of the TXRF-SC spectrometer and one characterized by standard optical scheme are compared. The slitless collimator of the x-ray radiation is formed by two quartz polished plates mated together. Lengths of the plates are not equal. The target is placed on the surface of the long quartz plate and produces the continuation of the initial slitless collimator. Target orientation problem vanishes but problem of the surface contact effect appears. The secondary x-ray radiation excitated in a surface of the target is led out across the hole in the long quartz plate. The radiation is registered by a standard Si (Li) semiconductor detector and is collected by a multi-channel analyzer. The fundamental difference of the x-ray optical scheme been unique to TXRF-SC spectrometer from the standard one is the excitation of a studied surface by a flared x-ray beam with angle ΔΘ = 2Θ c , where Θ c is the critical angle of the total reflection. The vital peculiarity of a x-ray slitless collimation is the absence of a radiation monochromatism in output of the collimator. The sensible divergence of the x-ray excitating beam and the availability in it of monochromatic and white radiation alike allow to get in the surface layer of target the

On the methods of determination of x-ray sources protection quality in x-ray diagnostic equipment

International Nuclear Information System (INIS)

Vladimirov, L.V.

1973-01-01

Existing procedures for assessing the quality of shielding of X-ray radiators are compared; these procedures are shown to have a number of shortcomings and to be very time-consuming. A procedure is offered in which shielding quality is tested in two stages: (1) X-ray tests aimed at determining the quality of protection of the X-ray tube unit; and (2) dosimeter tests proper. The results of measurements are compared with maximum permissible dosage rate

Trace element distribution in the rat cerebellum

International Nuclear Information System (INIS)

Kwiatek, W.M.; Long, G.J.; Pounds, J.G.; Reuhl, K.R.; Hanson, A.L.; Jones, K.W.

1989-10-01

Spatial distributions and concentrations of trace elements (TE) in the brain are important because TE perform catalytic structural functions in enzymes which regulate brain function and development. We have investigated the distributions of TE in rat cerebellum. Structures were sectioned and analyzed by the Synchrotron Radiation Induced X-ray Emission (SRIXE) method using the NSLS X-26 white-light microprobe facility. Advantages important for TE analysis of biological specimens with x-ray microscopy include short time of measurement, high brightness and flux, good spatial resolution, multielemental detection, good sensitivity, and non-destructive irradiation. Trace elements were measured in thin rat brain sections of 20-micrometers thickness. The analyses were performed on sample volumes as small as 0.2 nl with Minimum Detectable Limits (MDL) of 50 ppb wet weight for Fe, 100 ppb wet weight for Cu, and Zn, and 1 ppM wet weight for Pb. The distribution of TE in the molecular cell layer, granule cell layer and fiber tract of rat cerebella was investigated. Both point analyses and two-dimensional semi-quantitative mapping of the TE distribution in a section were used

A dual-trace model for visual sensory memory.

Science.gov (United States)

Cappiello, Marcus; Zhang, Weiwei

2016-11-01

Visual sensory memory refers to a transient memory lingering briefly after the stimulus offset. Although previous literature suggests that visual sensory memory is supported by a fine-grained trace for continuous representation and a coarse-grained trace of categorical information, simultaneous separation and assessment of these traces can be difficult without a quantitative model. The present study used a continuous estimation procedure to test a novel mathematical model of the dual-trace hypothesis of visual sensory memory according to which visual sensory memory could be modeled as a mixture of 2 von Mises (2VM) distributions differing in standard deviation. When visual sensory memory and working memory (WM) for colors were distinguished using different experimental manipulations in the first 3 experiments, the 2VM model outperformed Zhang and Luck (2008) standard mixture model (SM) representing a mixture of a single memory trace and random guesses, even though SM outperformed 2VM for WM. Experiment 4 generalized 2VM's advantages of fitting visual sensory memory data over SM from color to orientation. Furthermore, a single trace model and 4 other alternative models were ruled out, suggesting the necessity and sufficiency of dual traces for visual sensory memory. Together these results support the dual-trace model of visual sensory memory and provide a preliminary inquiry into the nature of information loss from visual sensory memory to WM. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Geophysical applicability of aerosol size distribution measurements using cascade impactors and proton induced X-ray emission

International Nuclear Information System (INIS)

Van Grieken, R.E.; Johansson, T.B.; Akselsson, K.R.; Winchester, J.W.; Nelson, J.W.; Chapman, K.R.

1976-01-01

Proton Induced X-ray Emission, (PIXE), is capable of high precision analysis for trace element components of aerosol particle size fractions sampled by cascade impactor. A statistical evaluation of data quality has been carried out in order to distinguish between analytical uncertainties in the PIXE procedure, errors caused by cascade impactor performance and by other factors in the sampling procedure, and geophysical causes of differences in composition and particle size distributions of the elements in aerosols. Replicate analyses and simultaneous samplings taken in north Florida and St. Louis have been used for the data evaluation. In addition to the analytical error the sampling procedure contributes an error of approximately 10% to be added quadratically. The resulting precision is sufficient to evaluate the data in geophysical terms. This is illustrated by means of sample sets taken simultaneously in an urban, forest and coastal environment of the same region. (author)

Anion-exchange Studies of Radioactive Trace Elements in Sulphuric Acid Solutions

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1963-01-15

As part of a chemical group separation procedure used as a pretreatment in gamma spectrometric analysis, a study has been made of the adsorption from sulphuric acid solutions on strongly basic anion exchange resins, prepared in the hydroxide and the sulphate forms, of trace activities of Na, P, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Mo, Tc, Ag, Cd, In, Cs, Ba, La, Ce, Hf, Ta, W, Ir, Pa and Np. Besides adsorbing some of the trace elements in the solution, the anion exchange resin in the hydroxide form will neutralize the bulk of the sulphuric acid. This makes possible the subsequent sequential separation of chloride complexes on short anion-exchange columns by a stepwise increasing of the HCl concentration of the solution. On the basis of the results obtained in the present and earlier experiments, a new improved chemical group-separation procedure for mixtures of radioactive trace elements is outlined.

Intra- and interobserver variability of MRI-based volume measurements of the hippocampus and amygdala using the manual ray-tracing method

International Nuclear Information System (INIS)

Achten, E.; Deblaere, K.; Damme, F. van; Kunnen, M.; Wagter, C. de; Boon, P.; Reuck, J. de

1998-01-01

We studied the intra- and interobserver variability of volume measurments of the hippocampus (HC) and the amygdala as applied to the detection of HC atrophy in patients with complex partial seizures (CPE), measuring the volumes of the HC and amygdala of 11 normal volunteers and 12 patients with presumed CPE, using the manual ray-tracing method. Two independent observers performed these measurements twice each using home-made software. The intra- and interobserver variability of the absolute volumes and of the normalised left-to-right volume differences (δV) between the HC (δV HC ), the amygdala (δV A ) and the sum of both (δV HCA) were assessed. In our mainly right-handed normals, the right HC and amygdala were on average 0.05 and 0.03 ml larger respectively than on the left. The interobserver variability for volume measurements in normal subjects was 1.80 ml for the HC and 0.82 ml for the amygdala, the intraobserver variability roughly one third of these values. The interobserver variability coefficient in normals was 3.6 % for δV HCA , 4.7 % for δV HC and 7.3 % for δV A . The intraobserver variability coefficient was 3.4 % for δV HCA , 4.2 % for δV HC amd 5.6 % for δV A . The variability in patients was the same for volume differences less than 5 % either side of the interval for normality, but was higher when large volume differences were encountered, is probably due to the lack of thresholding and/or normalisation. Cutoff values for lateralisation with the δV were defined. No intra- or interobserver lateralisation differences were encountered with δV HCA and δV HC . From these observations we conclude that the manual ray-tracing method is a robust method for lateralisation in patients with TLE. Due to its higher variability, this method is less suited to measure absolute volumes. (orig.) (orig.)

Intra- and interobserver variability of MRI-based volume measurements of the hippocampus and amygdala using the manual ray-tracing method

Energy Technology Data Exchange (ETDEWEB)

Achten, E.; Deblaere, K.; Damme, F. van; Kunnen, M. [MR Department 1K12, University Hospital Gent (Belgium); Wagter, C. de [Department of Radiotherapy and Nuclear Medicine, University Hospital Gent (Belgium); Boon, P.; Reuck, J. de [Department of Neurology, University Hospital Gent (Belgium)

1998-09-01

We studied the intra- and interobserver variability of volume measurments of the hippocampus (HC) and the amygdala as applied to the detection of HC atrophy in patients with complex partial seizures (CPE), measuring the volumes of the HC and amygdala of 11 normal volunteers and 12 patients with presumed CPE, using the manual ray-tracing method. Two independent observers performed these measurements twice each using home-made software. The intra- and interobserver variability of the absolute volumes and of the normalised left-to-right volume differences ({delta}V) between the HC ({delta}V{sub HC}), the amygdala ({delta}V{sub A}) and the sum of both ({delta}V{sub HCA)} were assessed. In our mainly right-handed normals, the right HC and amygdala were on average 0.05 and 0.03 ml larger respectively than on the left. The interobserver variability for volume measurements in normal subjects was 1.80 ml for the HC and 0.82 ml for the amygdala, the intraobserver variability roughly one third of these values. The interobserver variability coefficient in normals was 3.6 % for {delta}V{sub HCA}, 4.7 % for {delta}V{sub HC} and 7.3 % for {delta}V{sub A}. The intraobserver variability coefficient was 3.4 % for {delta}V{sub HCA}, 4.2 % for {delta}V{sub HC} amd 5.6 % for {delta}V{sub A}. The variability in patients was the same for volume differences less than 5 % either side of the interval for normality, but was higher when large volume differences were encountered, is probably due to the lack of thresholding and/or normalisation. Cutoff values for lateralisation with the {delta}V were defined. No intra- or interobserver lateralisation differences were encountered with {delta}V{sub HCA} and {delta}V{sub HC}. From these observations we conclude that the manual ray-tracing method is a robust method for lateralisation in patients with TLE. Due to its higher variability, this method is less suited to measure absolute volumes. (orig.) (orig.) With 2 figs., 7 tabs., 23 refs.

Studies of trace elements in biological systems by energy dispersive x-ray fluorescence (EDXRF) and proton induced x-ray emission (PIXE) methods

International Nuclear Information System (INIS)

Lal, Madan; Choudhury, R.K.

1991-01-01

Applicability of EDXRF and PIXE techniques for trace elemental analysis in biology and medicine is demonstrated. Due to increasing importance of the need to determine the role of essential and toxic trace elements in human health and disease, the method of PIXE analysis has assumed great importance in recent years. This method has been found to be particularly useful for biological samples. EDXRF also offers a complimentary method particularly in the range of elements of Z=45 to 60 where the sensitivity of PIXE analysis is not quite adequate. EDXRF can also be usefully employed for other elements of the periodic chart with relatively lesser sensitivity. The work being presented here includes trace element analysis of normal and cancer bearing tissues of Swiss mice, trace element profiles in cancerous human oesophageal tissues, investigations on the effect of toxic metals such as Hg from Ayurvedic drugs on Wister rats, and investigations of blood lead levels of children admitted to Sion Hospital from Dharavi slums of Bombay. The results of these investigations are presented and discussed. (author). 21 refs., 8 figs., 3 tabs

The reliability of head film measurements. 3. Tracing superimposition.

Science.gov (United States)

Baumrind, S; Miller, D; Molthen, R

1976-12-01

The superimposition of tracings from lateral skull x-ray films taken at different timepoints is an important method for assessing developmental and treatment changes through time. The usefulness of the data derived is, however, limited by the fact that the physical act of superimposing tracings is performed with some error. The magnitudes of error for superimpositions on different "planes" have not been amenable to quantitation by previously available methods. Using newly developed computer-aided techniques, we have been able to quantitate both the primary errors of tracing superimposition and the associated secondary landmark displacements for four conventionally employed anatomic reference "planes". For each reference "plane," twenty-five independent film pairs were examined independently by each of four judges. Therefore, 100 acts of tracing superimposition were available for each reference "plane." Output data are presented which appear to support the conclusion that measurement errors in tracing superimposition are a consequential factor affecting the confidence which should be placed in head film comparisons, particularly with regard to individual cases. Some consequences of this conclusion with respect to growth prediction and to the evaluation of treatment effects are considered.

The analysis, by a fusion procedure and X-ray-fluorescence spectrometry, of silicates and slags

International Nuclear Information System (INIS)

Jacobs, J.J.; Balaes, A.M.E.

1980-01-01

A glass-disc fusion method is described for the analysis, by X-ray-fluorescence spectrometry, of slags and silicate materials. The data are corrected for detector dead time and short-term instrumental drift. Corrections are made for matrix variations by use of the Lachange-Traill mathematical model, and the results are processed on a mini-computer, an iterative procedure being used in the solving of the simultaneous equations. As the alpha-correction coefficients of the Lachange-Traill model are not truly constant, a modified version of the model is proposed [af

Characterization of monoclinic crystals in tablets by pattern-fitting procedure using X-ray powder diffraction data.

Science.gov (United States)

Yamamura, Shigeo; Momose, Yasunori

2003-06-18

The purpose of this study is to characterize the monoclinic crystals in tablets by using X-ray powder diffraction data and to evaluate the deformation feature of crystals during compression. The monoclinic crystals of acetaminophen and benzoic acid were used as the samples. The observed X-ray diffraction intensities were fitted to the analytic expression, and the fitting parameters, such as the lattice parameters, the peak-width parameters, the preferred orientation parameter and peak asymmetric parameter were optimized by a non-linear least-squares procedure. The Gauss and March distribution functions were used to correct the preferred orientation of crystallites in the tablet. The March function performed better in correcting the modification of diffraction intensity by preferred orientation of crystallites, suggesting that the crystallites in the tablets had fiber texture with axial orientation. Although a broadening of diffraction peaks was observed in acetaminophen tablets with an increase of compression pressure, little broadening was observed in the benzoic tablets. These results suggest that "acetaminophen is a material consolidating by fragmentation of crystalline particles and benzoic acid is a material consolidating by plastic deformation then occurred rearrangement of molecules during compression". A pattern-fitting procedure is the superior method for characterizing the crystalline drugs of monoclinic crystals in the tablets, as well as orthorhombic isoniazid and mannitol crystals reported in the previous paper.

Film replacement by digital x-ray detectors - the correct procedure and equipment

International Nuclear Information System (INIS)

Ewert, U.; Zscherpel, U.; Bavendiek, K.

2004-01-01

New digital detectors were developed for medical applications, which have the potential to substitute the X-ray film and revolutionise the radiological technique. Digital Detector Arrays (DDA: Flat Panel Detectors, Line Detectors) and Imaging Plates (Computed Radiography) allow a fast detection of radiographic images in a shorter time and with higher dynamic than film applications. Companies report about a reduction of exposure time down to 5 - 25% in comparison to NDT film exposures. This provides together with the reduction of consumables economical (and also ecological) benefits and short amortisation periods. But this does not always provide the same image quality as NDT film. The requirements of the European and USA standards for film radiography are analysed to derive correct requirements for the digital image quality and procedures for prediction and measurement of image quality. Basically the USA standards seem to be more tolerant for these new innovative technologies. New standard proposals use signal/noise ratio and unsharpness as dominant parameters for image quality. Specialised measurement procedures are described. The properties of the new detectors can be controlled by electronics and exposure conditions. New names appear in literature like 'direct radiography' and 'film replacement techniques'. The basic advantage of the new digital techniques is the possibility to use numeric procedures for image interpretation. Industrial radiology can be optimised for crack detection as well as for analysis of flaw depth and shape measurement. Automated flaw detection, measurement of part dimensions and detection of completeness are used for serial part inspection devices. Parallel to the development of DDA's, an extraordinary increase of Computed Tomography (CT) applications can be observed. (author)

Energy-dispersive X-ray fluorescence – A tool for interdisciplinary ...

Indian Academy of Sciences (India)

Keywords. Energy-dispersive X-ray fluorescence; trace elements; oral cancer; biomonitoring; air pollution. Abstract. Trace elements have been at the focus of attention for decades with considerable emphasis on their role in biology and biomedical sciences, environmental sciences, geology, archaeology and material ...

X-ray fluorescence spectroscopic determination of heavy metals and ...

African Journals Online (AJOL)

Purpose: To determine the heavy metal and trace element composition of the powdered aerial parts of Origanum sipyleum L. and its water extract. Methods: The heavy metal and trace elements content of the powdered plant material and 2 % aqueous extract were evaluated by x-ray fluorescence spectroscopy with silicon ...

Trace conditioning in insects-keep the trace!

Science.gov (United States)

Dylla, Kristina V; Galili, Dana S; Szyszka, Paul; Lüdke, Alja

2013-01-01

Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination-a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

Modelling of waves propagation on irregular surfaces using ray tracing and GTD approaches: Application to head waves simulation in TOFD inspections for NDT

International Nuclear Information System (INIS)

Ferrand, Adrien; Darmon, Michel; Chatillon, Sylvain; Deschamps, Marc

2014-01-01

The Time of Flight Diffraction (TOFD) technique is a classical ultrasonic method used in ultrasonic non-destructive evaluation, which allows a precise positioning and a quantitative size evaluation of cracks in the inspected material. Among the typical phenomena arising in the current TOFD inspection, the so-called 'head wave' is the first contribution reaching the receiver. The head wave propagation on a planar interface is well known and identified as a critical refraction taking place on the material surface. On irregular surfaces, it has been shown that the head wave results from the melting of surface and bulk waves mechanisms and that surface irregularities are responsible for numerous diffractions of the incident head wave. To simulate such behaviour, a model has been developed using a ray tracing technique based on time of flight minimization (generalized Fermat's principle). It enables the calculation of the ray path and the corresponding time of flight of all waves propagating in the material, including the head wave. To obtain a complete propagation model for these waves (both trajectory and amplitude), the integration of Geometrical Theory of Diffraction (GTD) models is currently performed by coupling them with the ray-based approach discussed above.

Simple simultaneous determination of soluble and insoluble trace metal components in sea salts by a combined coprecipitation/X-ray fluorescence method

International Nuclear Information System (INIS)

Iwatsuki, Masaaki; Ali, Muhammad; Kyotani, Tomohiro; Fukasawa, Tsutomu

1996-01-01

An X-ray fluorescence method using the coprecipitation-preconcentration technique has been developed for simple determination of both acid-soluble and insoluble trace metal components, such as manganese, iron, nickel, copper and zinc in sea salts. A salt sample is dissolved in a nitric acid solution, and the residue is filtered off onto a membrane filter. After the pH is adjusted to 7-8, the filtrate is boiled, followed by addition of aluminum carrier, oxine and thionalide solutions. The solution is re-adjusted to pH 9, and kept at 80-85degC for 60 min. The precipitates are filtered off onto another membrane filter. X-Ray fluorescence intensities from two filters loaded with the residue and precipitates are measured and the concentrations of the elements are determined simultaneously using the calibration curves. Detection limits were 0.01 μg g -1 for manganese and copper, 0.04 μg g -1 for nickel and zinc, and 0.05 μg g -1 for iron, regardless of the soluble and the insoluble components. The present method was successfully applied to the analysis of sea salt samples. (author)

Unravelling the App Store: towards an interpretative perspective on tracing

DEFF Research Database (Denmark)

Grenz, Tilo; Kirschner, Heiko

2018-01-01

to be contextualized. This seems even more important since all types of digital traces are molded by specific operations, procedures as well as methods inscribed into digital infrastructures. These infrastructures are the necessary precondition for the emergence of digital traces, yet they pose a challenge...... capabilities are the result of continuous negotiation processes. The presented methodology of the paper thereby bridges the debates on the moving architectures of digital media and the search for suitable process-driven approaches....

INAA Application for Trace Element Determination in Biological Reference Material

Science.gov (United States)

Atmodjo, D. P. D.; Kurniawati, S.; Lestiani, D. D.; Adventini, N.

2017-06-01

Trace element determination in biological samples is often used in the study of health and toxicology. Determination change to its essentiality and toxicity of trace element require an accurate determination method, which implies that a good Quality Control (QC) procedure should be performed. In this study, QC for trace element determination in biological samples was applied by analyzing the Standard Reference Material (SRM) Bovine muscle 8414 NIST using Instrumental Neutron Activation Analysis (INAA). Three selected trace element such as Fe, Zn, and Se were determined. Accuracy of the elements showed as %recovery and precision as %coefficient of variance (%CV). The result showed that %recovery of Fe, Zn, and Se were in the range between 99.4-107%, 92.7-103%, and 91.9-112%, respectively, whereas %CV were 2.92, 3.70, and 5.37%, respectively. These results showed that INAA method is precise and accurate for trace element determination in biological matrices.

Trace-element analysis in environmental sciences

International Nuclear Information System (INIS)

Valkovic, V.; Moschini, G.

1988-01-01

The use of charged-particle accelerators in trace-element analysis in the field of environmental sciences is described in this article. Nuclear reactions, charged-particle-induced X-ray emission as well as other nuclear and atomic processes can be used individually, or combined, in developing adequate analytical systems. In addition to concentration levels, concentration levels, concentration profiles can be measured, resulting in unique information. Some examples of experiments performed are described together with the suggestions for future measurements [pt

Workflow optimisation for multimodal imaging procedures: a case of combined X-ray and MRI-guided TACE.

Science.gov (United States)

Fernández-Gutiérrez, Fabiola; Wolska-Krawczyk, Malgorzata; Buecker, Arno; Houston, J Graeme; Melzer, Andreas

2017-02-01

This study presents a framework for workflow optimisation of multimodal image-guided procedures (MIGP) based on discrete event simulation (DES). A case of a combined X-Ray and magnetic resonance image-guided transarterial chemoembolisation (TACE) is presented to illustrate the application of this method. We used a ranking and selection optimisation algorithm to measure the performance of a number of proposed alternatives to improve a current scenario. A DES model was implemented with detail data collected from 59 TACE procedures and durations of magnetic resonance imaging (MRI) diagnostic procedures usually performed in a common MRI suite. Fourteen alternatives were proposed and assessed to minimise the waiting times and improve workflow. Data analysis observed an average of 20.68 (7.68) min of waiting between angiography and MRI for TACE patients in 71.19% of the cases. Following the optimisation analysis, an alternative was identified to reduce waiting times in angiography suite up to 48.74%. The model helped to understand and detect 'bottlenecks' during multimodal TACE procedures, identifying a better alternative to the current workflow and reducing waiting times. Simulation-based workflow analysis provides a cost-effective way to face some of the challenges of introducing MIGP in clinical radiology, highligthed in this study.

Effect of soil moisture on trace elements concentrations using ...

African Journals Online (AJOL)

Portable X-ray fluorescence (PXRF) technology can offer rapid and cost-effective determination of the trace elements concentrations in soils. The aim of this study was to assess the influence of soil moisture content under different condition on PXRF measurement quality. For this purpose, PXRF was used to evaluate the soil ...

Dose distributions of a proton beam for eye tumor therapy: Hybrid pencil-beam ray-tracing calculations

International Nuclear Information System (INIS)

Rethfeldt, Ch.; Fuchs, H.; Gardey, K.-U.

2006-01-01

For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by folding the entrance fluence distribution with the pencil beam distribution widening with growing depth in the tissue, (ii) rescaling the spread-out Bragg peak dose distribution in water with the radiological path length calculated voxel by voxel on ray traces through a realistic density matrix for the treatment geometry, yielding a trajectory dependence of the geometrical range. Distributions calculated for some specific situations are compared to measurements and/or standard calculations, and differences to the latter are discussed with respect to the requirements of therapy planning. The most pronounced changes appear for wedges placed in front of the eye, causing additional widening of the lateral falloff. The more accurate prediction of the dose dependence at the field borders is of interest with respect to side effects in the risk organs of the eye

Ion induced x-ray emission

International Nuclear Information System (INIS)

Cohen, D.D.; Clayton, E.

1989-01-01

This paper discusses particle induced x-ray emission (PIXE). Its use as a tool for multi-element non-destructive trace element analysis of small samples is addressed. Concepts and details needed for the construction of a PIXE system are offered

Investigation of Pink Tourmalines by X-ray Fluorescent Technique

International Nuclear Information System (INIS)

Sangariyavanich, A.; Na Songkhla, S.; Pimjum, S.

1998-01-01

X-ray fluorescent technique has been employed in the study of trace elements in six samples of gamma irradiated pink tourmalines, namely, red-pink (rubellite), light-pink, orange-pink, brownish orange-pink, purple red and purple orange-pink. The analysis of their characteristic X-ray indicated the existence of manganese in all samples. Trace amounts of iron, zinc, lead, bismuth or gallium were also investigated in certain samples. Since these elements were not present in red-pink tourmaline, therefore, we believed that manganese is the major cause of pink color in tourmaline while other elements produce various types of pink color

13.1 micrometers hard X-ray focusing by a new type monocapillary X-ray optic designed for common laboratory X-ray source

Science.gov (United States)

Sun, Xuepeng; zhang, Xiaoyun; Zhu, Yu; Wang, Yabing; Shang, Hongzhong; Zhang, Fengshou; Liu, Zhiguo; Sun, Tianxi

2018-04-01

A new type of monocapillary X-ray optic, called 'two bounces monocapillary X-ray optics' (TBMXO), is proposed for generating a small focal spot with high power-density gain for micro X-ray analysis, using a common laboratory X-ray source. TBMXO is consists of two parts: an ellipsoidal part and a tapered part. Before experimental testing, the TBMXO was simulated by the ray tracing method in MATLAB. The simulated results predicted that the proposed TBMXO would produce a smaller focal spot with higher power-density gain than the ellipsoidal monocapillary X-ray optic (EMXO). In the experiment, the TBMXO performance was tested by both an optical device and a Cu target X-ray tube with focal spot of 100 μm. The results indicated that the TBMXO had a slope error of 57.6 μrad and a 13.1 μm focal spot and a 1360 gain in power density were obtained.

Solar Ray Tracing Analysis to Determine Energy Availability in a CPC Designed for Use as a Residential Water Heater

Directory of Open Access Journals (Sweden)

Miguel Terrón-Hernández

2018-01-01

Full Text Available Compound parabolic concentrators are relevant systems used in solar thermal technology. With adequate tailoring, they can be used as an efficient and low-cost alternative in residential water heating applications. This work presents a simulation study using a ray tracing analysis. With this technique, we simulate the interaction between solar rays and solar concentrator to quantify the amount of energy that impinges on the receiver at a particular time. Energy availability is evaluated in a comparison of two configurations throughout the year: static setup at 21° and multi-position setup; tilted with respect to the horizontal, depending on three seasonal positions: 0° for summer, 16° for spring/autumn, and 32° for winter, with the aim to evaluate the amount of available energy in each season. The fact that a tracking system can be dispensed with also represents an economical option for the proposed application. The results showed that at 21°, the proposed solar Compound Parabolic Concentrator (CPC works satisfactorily; however, by carrying out the selected angular adjustments, the overall energy availability increased by 22%, resulting in a more efficient option. The most effective design was also built and analyzed outdoors. The obtained thermal efficiency was of ~43%. The optical design and its evaluation developed herein proved to be a valuable tool for prototype design and performance evaluation.

X-Rays: MedlinePlus Health Topic

Science.gov (United States)

... Radiological Society of North America) Also in Spanish Tracing the X-Ray Trail (American Society of Radiologic ... also links to health information from non-government Web sites. See our disclaimer about external links and ...

Bone X-Ray (Radiography)

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Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? A ...

Bone X-Ray (Radiography)

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Full Text Available ... current x-ray images for diagnosis and disease management. top of page How is the procedure performed? ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ...

International comparison of interpolation procedures for the efficiency of germanium gamma-ray spectrometers (GAM83 exercise)

International Nuclear Information System (INIS)

Zijp, W.L.; Polle, A.N.; Nolthenius, H.J.

1986-01-01

Results are presented for the outcome of an international intercomparison of a particular gamma-ray spectrometric procedure. Laboratories were asked to determine full energy peak efficiencies and activities by means of their own procedures, starting from supplied peak-efficiency data. Four data sets for four different conditions of germanium detectors were distributed. The sets comprised: a high accuracy- (uncertainty > 1%) data set with a relatively large number of measured data (SET 1); a low accuracy- (uncertainty 3-5%) data set with a relatively small number of measured data (SET 2); a low energy-data set (SET 3); a high accuracy-data set with a relatively small number of measured data (SET 4). The intercomparison (coded GAM83) was organized and analyzed under auspices of the International Committee for Radionuclide Metrology (ICRM). The results comprise the analysis of the contributions of 41 participants

Trace element profiles in modern horse molar enamel as tracers of seasonality: Evidence from micro-XRF, LA-ICP-MS and stable isotope analysis

Science.gov (United States)

de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

2016-04-01

A combination of laboratory micro-X-ray Fluorescence (μXRF) and stable carbon and oxygen isotope analysis shows that trace element profiles from modern horse molars reveal a seasonal pattern that co-varies with seasonality in the oxygen isotope records of enamel carbonate from the same teeth. A combination of six cheek teeth (premolars and molars) from the same individual yields a seasonal isotope and trace element record of approximately three years recorded during the growth of the molars. This record shows that reproducible measurements of various trace element ratios (e.g., Sr/Ca, Zn/Ca, Fe/Ca, K/Ca and S/Ca) lag the seasonal pattern in oxygen isotope records by 2-3 months. Laser Ablation-ICP-Mass Spectrometry (LA-ICP-MS) analysis on a cross-section of the first molar of the same individual is compared to the bench-top tube-excitation μXRF results to test the robustness of the measurements and to compare both methods. Furthermore, trace element (e.g. Sr, Zn, Mg & Ba) profiles perpendicular to the growth direction of the same tooth, as well as profiles parallel to the growth direction are measured with LA-ICP-MS and μXRF to study the internal distribution of trace element ratios in two dimensions. Results of this extensive complementary line-scanning procedure shows the robustness of state of the art laboratory micro-XRF scanning for the measurement of trace elements in bioapatite. The comparison highlights the advantages and disadvantages of both methods for trace element analysis and illustrates their complementarity. Results of internal variation within the teeth shed light on the origins of trace elements in mammal teeth and their potential use for paleo-environmental reconstruction.

Trace elements measurement by PIXE in the appraisal of the ancient potteries

International Nuclear Information System (INIS)

Zhang, Z.Q.; Cheng, H.S.; Xia, H.N.; Jiang, J.C.; Gao, M.H.; Yang, F.J.

2002-01-01

Fifty pieces of pottery samples were collected from two domains with different types of ancient Sino-civilization. The concentrations of trace elements Cr, Ni, Cu, Zn, Pb, Rb, Sr, Y and Zr were measured by proton-induced X-ray emission technique. Multivariate statistical processing of the results allows us to locate the provenance of the ancient potteries. The experimental results also show that the relative trace element contents Ni-Rb-Zr are useful for distinguishing these two types of Chinese ancient potteries

Mineral elements and essential trace elements in blood of seals of the North Sea measured by total-reflection X-ray fluorescence analysis