The Simbol-X Low Energy Detector

International Nuclear Information System (INIS)

Lechner, Peter

2009-01-01

For the Low Energy Detector of Simbol-X a new type of active pixel sensor based on the integrated amplifier DEPFET has been developed. This concept combines large area, scalable pixel size, low noise, and ultra-fast readout. Flight representative prototypes have been processed with a performance matching the Simbol-X specifications and demonstrating the technology readiness.

The Simbol-X Low Energy Detector

Science.gov (United States)

Lechner, Peter

2009-05-01

For the Low Energy Detector of Simbol-X a new type of active pixel sensor based on the integrated amplifier DEPFET has been developed. This concept combines large area, scalable pixel size, low noise, and ultra-fast readout. Flight representative prototypes have been processed with a performance matching the Simbol-X specifications and demonstrating the technology readiness.

Simbol-X Core Science in a Context

Science.gov (United States)

Fiore, F.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Cledassou, R.; Counil, J. L.; Comastri, A.; Ferrando, P.; Giommi, P.; Goldwurm, A.; Lamarle, O.; Lanzuisi, G.; Laurent, P.; Lebrun, F.; Malaguti, G.; Mereghetti, S.; Micela, G.; Pareschi, G.; Piconcelli, E.; Piermaria, M.; Puccetti, S.; Roques, J.-P.; Tagliaferri, G.; Vignali, C.

2009-05-01

Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to ~80 keV, providing an improvement of roughly three orders of magnitude in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This will open a new window in X-ray astronomy, allowing breakthrough studies on black hole physics and census and particle acceleration mechanisms. We discuss here synergies between Simbol-X and the main multiwavelength facilities that will operate in the next decade, and present a quantitative comparison between Simbol-X and its main competitors, NuStar and Astro-H.

Simbol-X Core Science in a Context

International Nuclear Information System (INIS)

Fiore, F.; Lanzuisi, G.; Piconcelli, E.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Giommi, P.; Piermaria, M.; Puccetti, S.; Cledassou, R.; Counil, J. L.; Lamarle, O.; Comastri, A.; Ferrando, P.; Goldwurm, A.; Laurent, P.; Lebrun, F.; Malaguti, G.; Mereghetti, S.; Micela, G.

2009-01-01

Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to ∼80 keV, providing an improvement of roughly three orders of magnitude in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This will open a new window in X-ray astronomy, allowing breakthrough studies on black hole physics and census and particle acceleration mechanisms. We discuss here synergies between Simbol-X and the main multiwavelength facilities that will operate in the next decade, and present a quantitative comparison between Simbol-X and its main competitors, NuStar and Astro-H.

Simulation of the Simbol-X telescope: imaging performance of a deformable x-ray telescope

Science.gov (United States)

Chauvin, Maxime; Roques, Jean-Pierre

2009-08-01

We have developed a simulation tool for a Wolter I telescope subject to deformations. The aim is to understand and predict the behavior of Simbol-X and other future missions (NuSTAR, Astro-H, IXO, ...). Our code, based on Monte-Carlo ray-tracing, computes the full photon trajectories up to the detector plane, along with the deformations. The degradation of the imaging system is corrected using metrology. This tool allows to perform many analyzes in order to optimize the configuration of any of these telescopes.

The Simbol-X Mission

Science.gov (United States)

Ferrando, P.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Clédassou, R.; Counil, J. L.; Fiore, F.; Giommi, P.; Goldwurm, A.; Lamarle, O.; Laurent, P.; Lebrun, F.; Malaguti, G.; Mereghetti, S.; Micela, G.; Pareschi, G.; Piermaria, M.; Roques, J. P.; Santangelo, A.; Tagliaferri, G.

2009-05-01

The elucidation of key questions in astrophysics, in particular those related to black hole physics and census, and to particle acceleration mechanisms, necessitates to develop new observational capabilities in the hard X-ray domain with performances several orders of magnitude better than presently available. Relying on two spacecrafts in a formation flying configuration, Simbol-X will provide the world-wide astrophysics community with a single optics long focal length telescope. This observatory will have unrivaled performances in the hard X-ray domain, up to ~80 keV, as well as very good characteristics in the soft X-ray domain, down to ~0.5 keV. The Simbol-X mission has successfully passed a phase A study, jointly conducted by CNES and ASI, with the participation of German laboratories. It is now entering phase B studies with the participation of new international partners, for a launch in 2015. We give in this paper a general overview of the mission, as consolidated at the start of phase B.

The Simbol-X Mission

International Nuclear Information System (INIS)

Ferrando, P.; Goldwurm, A.; Laurent, P.; Lebrun, F.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Giommi, P.; Piermaria, M.; Cledassou, R.; Counil, J. L.; Lamarle, O.; Fiore, F.; Malaguti, G.; Mereghetti, S.; Micela, G.; Pareschi, G.; Tagliaferri, G.; Roques, J. P.; Santangelo, A.

2009-01-01

The elucidation of key questions in astrophysics, in particular those related to black hole physics and census, and to particle acceleration mechanisms, necessitates to develop new observational capabilities in the hard X-ray domain with performances several orders of magnitude better than presently available. Relying on two spacecrafts in a formation flying configuration, Simbol-X will provide the world-wide astrophysics community with a single optics long focal length telescope. This observatory will have unrivaled performances in the hard X-ray domain, up to ∼80 keV, as well as very good characteristics in the soft X-ray domain, down to ∼0.5 keV. The Simbol-X mission has successfully passed a phase A study, jointly conducted by CNES and ASI, with the participation of German laboratories. It is now entering phase B studies with the participation of new international partners, for a launch in 2015. We give in this paper a general overview of the mission, as consolidated at the start of phase B.

Simbol-X Formation Flight and Image Reconstruction

Science.gov (United States)

Civitani, M.; Djalal, S.; Le Duigou, J. M.; La Marle, O.; Chipaux, R.

2009-05-01

Simbol-X is the first operational mission relying on two satellites flying in formation. The dynamics of the telescope, due to the formation flight concept, raises a variety of problematic, like image reconstruction, that can be better evaluated via a simulation tools. We present here the first results obtained with Simulos, simulation tool aimed to study the relative spacecrafts navigation and the weight of the different parameters in image reconstruction and telescope performance evaluation. The simulation relies on attitude and formation flight sensors models, formation flight dynamics and control, mirror model and focal plane model, while the image reconstruction is based on the Line of Sight (LOS) concept.

Simbol-X: Synergies with JWST, ALMA and Herschel

Science.gov (United States)

Maiolino, R.

2009-05-01

I discuss the synergies between Simbol-X and three among the major astronomical facilities that, in the next decade, will be operative in the infrared-millimeter spectral range, namely JWST, Herschel and ALMA. I first provide a brief overview of the main features and observing capabilities offered by these facilities. Then I will discuss a few research fields (mostly extragalactic) that will geatly benefit of the joint exploitation of Simbol-X and these IR-mm observatories.

On the Compliance of Simbol-X Mirror Roughness with its Effective Area Requirements

Science.gov (United States)

Spiga, D.; Basso, S.; Cotroneo, V.; Pareschi, G.; Tagliaferri, G.

2009-05-01

Surface microroughness of X-ray mirrors is a key issue for the angular resolution of Simbol-X to comply with the required one (Simbol-X mirrors, in order to satisfy the required imaging capability, has already been derived in terms of its PSD (Power Spectral Density). However, also the Effective Area of the telescope is affected by the mirror roughness. In this work we will show how the expected effective area of the Simbol-X mirror module can be computed from the roughness PSD tolerance, checking its compliance with the requirements.

Design and development of the SIMBOL-X hard x-ray optics

Science.gov (United States)

Pareschi, G.; Attinà, P.; Basso, S.; Borghi, G.; Burkert, W.; Buzzi, R.; Citterio, O.; Civitani, M.; Conconi, P.; Cotroneo, V.; Cusumano, G.; Dell'Orto, E.; Freyberg, M.; Hartner, G. D.; Gorenstein, P.; Mattaini, E.; Mazzoleni, F.; Parodi, G.; Romaine, S.; Spiga, D.; Tagliaferri, G.; Valtolina, R.; Valsecchi, G.; Vernani, D.

2008-07-01

The SIMBOL-X formation-flight X-ray mission will be operated by ASI and CNES in 2014, with a large participation of the French and Italian high energy astrophysics scientific community. Also German and US Institutions are contributing in the implementation of the scientific payload. Thanks to the formation-flight architecture, it will be possible to operate a long (20 m) focal length grazing incidence mirror module, formed by 100 confocal multilayer-coated Wolter I shells. This system will allow us to focus X-rays over a very broad energy band, from 0.5 keV up to 80 keV and beyond, with more than two orders of magnitude improvement in angular resolution (20 arcsec HEW) and sensitivity (0.5 µCrab on axis @30 keV) compared to non focusing detectors used so far. The X-ray mirrors will be realized by Ni electroforming replication, already successfully used for BeppoSAX, XMM-Newton, and JET-X/SWIFT; the thickness trend will be about two times less than for XMM, in order to save mass. Multilayer reflecting coatings will be implemented, in order to improve the reflectivity beyond 10 keV and to increase the field of view 812 arcmin at 30 keV). In this paper, the SIMBOL-X optics design, technology and implementation challenges will be discussed; it will be also reported on recent results obtained in the context of the SIMBOL-X optics development activities.

Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

Science.gov (United States)

Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Rigato, V.; Spiga, D.; Tagliaferri, G.

2009-05-01

X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

International Nuclear Information System (INIS)

Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Rigato, V.

2009-01-01

X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

On the Compliance of Simbol-X Mirror Roughness with its Effective Area Requirements

International Nuclear Information System (INIS)

Spiga, D.; Basso, S.; Cotroneo, V.; Pareschi, G.; Tagliaferri, G.

2009-01-01

Surface microroughness of X-ray mirrors is a key issue for the angular resolution of Simbol-X to comply with the required one (<20 arcsec at 30 keV). The maximum tolerable microroughness for Simbol-X mirrors, in order to satisfy the required imaging capability, has already been derived in terms of its PSD (Power Spectral Density). However, also the Effective Area of the telescope is affected by the mirror roughness. In this work we will show how the expected effective area of the Simbol-X mirror module can be computed from the roughness PSD tolerance, checking its compliance with the requirements.

Heavily Obscured AGN with SIMBOL-X

International Nuclear Information System (INIS)

Ceca, R. Della; Caccianiga, A.; Severgnini, P.

2009-01-01

By comparing an optically selected sample of narrow lines AGN with an X-ray selected sample of AGN we have recently derived an estimate of the intrinsic (i.e. before absorption) 2-10 keV luminosity function (XLF) of Compton Thick AGNs. We will use this XLF to derive the number of Compton Thick AGN that will be found in the SIMBOL-X survey(s).

Heavily Obscured AGN with SIMBOL-X

Science.gov (United States)

Della Ceca, R.; Caccianiga, A.; Severgnini, P.

2009-05-01

By comparing an optically selected sample of narrow lines AGN with an X-ray selected sample of AGN we have recently derived an estimate of the intrinsic (i.e. before absorption) 2-10 keV luminosity function (XLF) of Compton Thick AGNs. We will use this XLF to derive the number of Compton Thick AGN that will be found in the SIMBOL-X survey(s).

Exploring Black Hole Accretion in Active Galactic Nuclei with Simbol-X

Science.gov (United States)

Goosmann, R. W.; Dovčiak, M.; Mouchet, M.; Czerny, B.; Karas, V.; Gonçalves, A.

2009-05-01

A major goal of the Simbol-X mission is to improve our knowledge about black hole accretion. By opening up the X-ray window above 10 keV with unprecedented sensitivity and resolution we obtain new constraints on the X-ray spectral and variability properties of active galactic nuclei. To interpret the future data, detailed X-ray modeling of the dynamics and radiation processes in the black hole vicinity is required. Relativistic effects must be taken into account, which then allow to constrain the fundamental black hole parameters and the emission pattern of the accretion disk from the spectra that will be obtained with Simbol-X.

What Can Simbol-X Do for Gamma-ray Binaries?

Science.gov (United States)

Cerutti, B.; Dubus, G.; Henri, G.; Hill, A. B.; Szostek, A.

2009-05-01

Gamma-ray binaries have been uncovered as a new class of Galactic objects in the very high energy sky (>100 GeV). The three systems known today have hard X-ray spectra (photon index ~1.5), extended radio emission and a high luminosity in gamma-rays. Recent monitoring campaigns of LSI +61°303 in X-rays have confirmed variability in these systems and revealed a spectral hardening with increasing flux. In a generic one-zone leptonic model, the cooling of relativistic electrons accounts for the main spectral and temporal features observed at high energy. Persistent hard X-ray emission is expected to extend well beyond 10 keV. We explain how Simbol-X will constrain the existing models in connection with Fermi Space Telescope measurements. Because of its unprecedented sensitivity in hard X-rays, Simbol-X will also play a role in the discovery of new gamma-ray binaries, giving new insights into the evolution of compact binaries.

What Can Simbol-X Do for Gamma-ray Binaries?

International Nuclear Information System (INIS)

Cerutti, B.; Dubus, G.; Henri, G.; Hill, A. B.; Szostek, A.

2009-01-01

Gamma-ray binaries have been uncovered as a new class of Galactic objects in the very high energy sky (>100 GeV). The three systems known today have hard X-ray spectra (photon index ∼1.5), extended radio emission and a high luminosity in gamma-rays. Recent monitoring campaigns of LSI +61 deg. 303 in X-rays have confirmed variability in these systems and revealed a spectral hardening with increasing flux. In a generic one-zone leptonic model, the cooling of relativistic electrons accounts for the main spectral and temporal features observed at high energy. Persistent hard X-ray emission is expected to extend well beyond 10 keV. We explain how Simbol-X will constrain the existing models in connection with Fermi Space Telescope measurements. Because of its unprecedented sensitivity in hard X-rays, Simbol-X will also play a role in the discovery of new gamma-ray binaries, giving new insights into the evolution of compact binaries.

A Fast Event Preprocessor and Sequencer for the Simbol-X Low Energy Detector

International Nuclear Information System (INIS)

Schanz, T.; Tenzer, C.; Maier, D.; Kendziorra, E.; Santangelo, A.

2009-01-01

The Simbol-X Low Energy Detector (LED), a 128x128 pixel DEPFET (Depleted Field Effect Transistor) array, will be read out at a very high rate (8000 frames/second) and, therefore, requires a very fast on board electronics. We present an FPGA-based LED camera electronics consisting of an Event Preprocessor (EPP) for on board data preprocessing and filtering of the Simbol-X low-energy detector and a related Sequencer (SEQ) to generate the necessary signals to control the readout.

Prospects for Simbol-X Observations of Magnetars

International Nuclear Information System (INIS)

Mereghetti, S.; Esposito, P.; Tiengo, A.; Israel, G. L.; Stella, L.; Goetz, D.; Rea, N.; Turolla, R.; Zane, S.

2009-01-01

Two small classes of high-energy sources, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have properties that are well explained by the ''magnetar'' model, postulating the existence of isolated neutron stars with supercritical magnetic fields (B∼10 14 -10 15 G). Thanks to Simbol-X, it shall be possible to study with unprecedented detail different aspects of the high-energy properties from these sources, both for what concerns their persistent emission as well as for their bursts and flares.

Prospects for Simbol-X Observations of Magnetars

Science.gov (United States)

Mereghetti, S.; Esposito, P.; Tiengo, A.; Israel, G. L.; Götz, D.; Rea, N.; Stella, L.; Turolla, R.; Zane, S.

2009-05-01

Two small classes of high-energy sources, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have properties that are well explained by the ``magnetar'' model, postulating the existence of isolated neutron stars with supercritical magnetic fields (B~1014-1015 G). Thanks to Simbol-X, it shall be possible to study with unprecedented detail different aspects of the high-energy properties from these sources, both for what concerns their persistent emission as well as for their bursts and flares.

A Fast Event Preprocessor and Sequencer for the Simbol-X Low Energy Detector

Science.gov (United States)

Schanz, T.; Tenzer, C.; Maier, D.; Kendziorra, E.; Santangelo, A.

2009-05-01

The Simbol-X Low Energy Detector (LED), a 128×128 pixel DEPFET (Depleted Field Effect Transistor) array, will be read out at a very high rate (8000 frames/second) and, therefore, requires a very fast on board electronics. We present an FPGA-based LED camera electronics consisting of an Event Preprocessor (EPP) for on board data preprocessing and filtering of the Simbol-X low-energy detector and a related Sequencer (SEQ) to generate the necessary signals to control the readout.

Simbol-X Mirror Module Thermal Shields: I-Design and X-Ray Transmission

Science.gov (United States)

Collura, A.; Barbera, M.; Varisco, S.; Basso, S.; Pareschi, G.; Tagliaferri, G.; Ayers, T.

2009-05-01

The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.

Simbol-X Mirror Module Thermal Shields: I - Design and X-Ray Transmission

International Nuclear Information System (INIS)

Collura, A.; Varisco, S.; Barbera, M.; Basso, S.; Pareschi, G.; Tagliaferri, G.; Ayers, T.

2009-01-01

The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.

Simbol-X: Imaging The Hard X-ray Sky with Unprecedented Spatial Resolution and Sensitivity

Science.gov (United States)

Tagliaferri, Gianpiero; Simbol-X Joint Scientific Mission Group

2009-01-01

Simbol-X is a hard X-ray mission, with imaging capability in the 0.5-80 keV range. It is based on a collaboration between the French and Italian space agencies with participation of German laboratories. The launch is foreseen in late 2014. It relies on a formation flight concept, with two satellites carrying one the mirror module and the other one the focal plane detectors. The mirrors will have a 20 m focal length, while the two focal plane detectors will be put one on top of the other one. This combination will provide over two orders of magnitude improvement in angular resolution and sensitivity in the hard X-ray range with respect to non-focusing techniques. The Simbol-X revolutionary instrumental capabilities will allow us to elucidate outstanding questions in high energy astrophysics such as those related to black-holes accretion physics and census, and to particle acceleration mechanisms. We will give an overall description of the mission characteristics, performances and scientific objectives.

The low energy detector of Simbol-X

Science.gov (United States)

Lechner, P.; Andricek, L.; Briel, U.; Hasinger, G.; Heinzinger, K.; Herrmann, S.; Huber, H.; Kendziorra, E.; Lauf, T.; Lutz, G.; Richter, R.; Santangelo, A.; Schaller, G.; Schnecke, M.; Schopper, F.; Segneri, G.; Strüder, L.; Treis, J.

2008-07-01

Simbol-X is a French-Italian-German hard energy X-ray mission with a projected launch in 2014. Being sensitive in the energy range from 500 eV to 80 keV it will cover the sensitivity gap beyond the energy interval of today's telescopes XMM-Newton and Chandra. Simbol-X will use an imaging telescope of nested Wolter-I mirrors. To provide a focal length of 20 m it will be the first mission of two independent mirror and detector spacecrafts in autonomous formation flight. The detector spacecraft's payload is composed of an imaging silicon low energy detector in front of a pixelated cadmium-telluride hard energy detector. Both have a sensitive area of 8 × 8 cm2 to cover a 12 arcmin field of view and a pixel size of 625 × 625 μm2 adapted to the telescope's resolution of 20 arcsec. The additional LED specifications are: high energy resolution, high quantum efficiency, fast readout and optional window mode, monolithic device with 100 % fill factor and suspension mounting, and operation at warm temperature. To match these requirements the low energy detector is composed of 'active macro pixels', combining the large, scalable area of a Silicon Drift Detector and the low-noise, on-demand readout of an integrated DEPFET amplifier. Flight representative prototypes have been processed at the MPI semiconductor laboratory, and the prototype's measured performance demonstrates the technology readiness.

The Integration Process of Very Thin Mirror Shells with a Particular Regard to Simbol-X

Science.gov (United States)

Basso, S.; Pareschi, G.; Tagliaferri, G.; Mazzoleni, F.; Valtolina, R.; Citterio, O.; Conconi, P.

2009-05-01

The optics of Simbol-X are very thin compared to previous X-ray missions (like XMM). Therefore their shells floppy and are unable to maintain the correct shape. To avoid the deformations of their very thin X-ray optics during the integration process we adopt two stiffening rings with a good roundness. In this article the procedure used for the first three prototypes of the Simbol-X optics is presented with a description of the problems involved and with an analysis of the degradation of the performances during the integration. This analysis has been performed with the UV vertical bench measurements at INAF-OAB.

Simbol-X Telescope Scientific Calibrations: Requirements and Plans

International Nuclear Information System (INIS)

Malaguti, G.; Raimondi, L.; Trifoglio, M.; Angelini, L.; Moretti, A.

2009-01-01

The Simbol-X telescope characteristics and the mission scientific requirements impose a challenging calibration plan with a number of unprecedented issues. The 20 m focal length implies for the incoming X-ray beam a divergence comparable to the incidence angle of the mirror surface also for 100 m-long facilities. Moreover this is the first time that a direct focussing X-ray telescope will be calibrated on an energy band covering about three decades, and with a complex focal plane. These problems require a careful plan and organization of the measurements, together with an evaluation of the calibration needs in terms of both hardware and software.

Simbol-X Telescope Scientific Calibrations: Requirements and Plans

Science.gov (United States)

Malaguti, G.; Angelini, L.; Raimondi, L.; Moretti, A.; Trifoglio, M.

2009-05-01

The Simbol-X telescope characteristics and the mission scientific requirements impose a challenging calibration plan with a number of unprecedented issues. The 20 m focal length implies for the incoming X-ray beam a divergence comparable to the incidence angle of the mirror surface also for 100 m-long facilities. Moreover this is the first time that a direct focussing X-ray telescope will be calibrated on an energy band covering about three decades, and with a complex focal plane. These problems require a careful plan and organization of the measurements, together with an evaluation of the calibration needs in terms of both hardware and software.

Study and optimisation of the high energy detector in Cd(Zn)Te of the Simbol-X space mission for X and gamma astronomy; Etude et optimisation du plan de detection de haute energie en Cd(Zn)Te pour la mission spatiale d'observation astronomie X et gamma SIMBOL-X

Energy Technology Data Exchange (ETDEWEB)

Meuris, A.

2009-09-15

Stars in final phases of evolution are sites of highest energetic phenomena of the Universe. The understanding of their mechanisms is based on the observation of the X and gamma rays from the sources. The Simbol-X French-Italian project is a novel concept of telescope with two satellites flying in formation. This space mission combines upgraded optics from X-ray telescopes with detection Systems from gamma-ray telescopes. CEA Saclay involved in major space missions for gamma astronomy is in charge of the definition and the design of the High Energy Detector (HED) of Simbol-X to cover the spectral range from 8 to 80 keV. Two generations of micro-cameras called Caliste have been designed, fabricated and tested. They integrate cadmium telluride (CdTe) crystals and optimised front-end electronics named Idef-X. The hybridization technique enables to put them side by side as a mosaic to achieve for the first time a CdTe detection plane with fine spatial resolution (600 {mu}m) and arbitrarily large surface. By setting up test benches and leading test campaigns, I was involved in the fabrication of Caliste prototypes and I assessed temporal, spatial and spectral resolutions. At the conclusion of experiments and simulations, I propose a detector type, operating conditions and digital processing on board the spacecraft to optimise HED performance. The best detector candidate is CdTe Schottky, well suited to high resolution spectroscopy; however, it suffers from lost in stability during biasing. Beyond Simbol-X mission, I studied theoretically and experimentally this kind of detector to build an updated model that can apply to other projects of gamma spectroscopy and imaging. (author)

Study and optimisation of the high energy detector in Cd(Zn)Te of the Simbol-X space mission for X and gamma astronomy

International Nuclear Information System (INIS)

Meuris, A.

2009-09-01

Stars in final phases of evolution are sites of highest energetic phenomena of the Universe. The understanding of their mechanisms is based on the observation of the X and gamma rays from the sources. The Simbol-X French-Italian project is a novel concept of telescope with two satellites flying in formation. This space mission combines upgraded optics from X-ray telescopes with detection Systems from gamma-ray telescopes. CEA Saclay involved in major space missions for gamma astronomy is in charge of the definition and the design of the High Energy Detector (HED) of Simbol-X to cover the spectral range from 8 to 80 keV. Two generations of micro-cameras called Caliste have been designed, fabricated and tested. They integrate cadmium telluride (CdTe) crystals and optimised front-end electronics named Idef-X. The hybridization technique enables to put them side by side as a mosaic to achieve for the first time a CdTe detection plane with fine spatial resolution (600 μm) and arbitrarily large surface. By setting up test benches and leading test campaigns, I was involved in the fabrication of Caliste prototypes and I assessed temporal, spatial and spectral resolutions. At the conclusion of experiments and simulations, I propose a detector type, operating conditions and digital processing on board the spacecraft to optimise HED performance. The best detector candidate is CdTe Schottky, well suited to high resolution spectroscopy; however, it suffers from lost in stability during biasing. Beyond Simbol-X mission, I studied theoretically and experimentally this kind of detector to build an updated model that can apply to other projects of gamma spectroscopy and imaging. (author)

SIMBOL-X: A Formation Flying Mission on HEO for Exploring the Universe

Science.gov (United States)

Gamet, Philippe; Epenoy, R.; Salcedo, C.

2007-01-01

SIMBOL-X is a high energy new generation telescope covering by a single instrument a continuous energy range starting at classical X-rays and extending to hard X-rays, i.e. from 0.5 to 80 keV. It is using in this field a focalizing payload which until now was used for energy below 10 keV only, via the construction of a telescope distributed on two satellites flying in formation. SIMBOL-X permits a gain of two orders of magnitude in sensibility and spatial resolution in comparison to state of the art hard X-rays instruments. The mirror satellite will be in free flight on a high elliptical orbit and will target the object to observe very precisely, thus focusing the hard X-ray emission thanks to this mirror module. At the focal point area which is situated 20 meters behind the mirror satellite, the detector satellite maintains its position on a forced orbit thanks to a radio link with the mirror satellite and a lateral displacement sensor using a beam emitted onboard the mirror satellite. This configuration is said "formation flying". The location of the detector satellite shall be very finely tuned as it carries the focal plane of this distributed telescope. To provide science measurements, the Simbol-X orbit has been chosen High elliptic (HEO), which means elliptical orbit with a high perigee altitude. Preliminary studies where made with an orbit with an altitude of the perigee of 44000km and altitude of the apogee of 253000km. The orbit was seven days ground track repeated in order to maintain a perigee pass over the Malindi ground station to download scientific telemetry. But as studies went on, difficulties in mass budget, link budget, perigee maintenance and formation flying maintenance were raised. This was mainly due to the vicinity of the Moon and its disturbing effect on the satellites orbits. Alternative orbits have been proposed in order to demonstrate the feasibility of the mission. The problematic of bringing the two satellites from their injection

Cloudy Skies over AGN: Observations with Simbol-X

Science.gov (United States)

Salvati, M.; Risaliti, G.

2009-05-01

Recent time-resolved spectroscopic X-ray studies of bright obscured AGN show that column density variability on time scales of hours/days may be common, at least for sources with NH>1023 cm-2. This opens new oppurtunities in the analysis of the structure of the circumnuclear medium and of the X-ray source: resolving the variations due to single clouds covering/uncovering the X-ray source provides tight constraints on the source size, the clouds' size and distance, and their average number, density and column density. We show how Simbol-X will provide a breakthrough in this field, thanks to its broad band coverage, allowing (a) to precisely disentangle the continuum and NH variations, and (2) to extend the NH variability analysis to column densities >1023 cm-2.

Simulation of a long focal length Wolter-I telescope for hard X-ray astronomy. Application to the Simbol-X and PheniX space missions

International Nuclear Information System (INIS)

Chauvin, M.

2011-01-01

The future of hard X-ray astronomy relies on the development of new instruments able to focus photons of a hundred keV. Indeed, focalization allows an important improvement in sensitivity and angular resolution. Achieved by grazing incidence reflections on Wolter-I mirrors, its use currently limited to tens of keV can be extended to higher energies thanks to a specific coating and a large focal length. As X-ray observations are only possible above the atmosphere, the size of the observatories, and hence their focal length, was limited by the launcher capacity. Over the past few years, different technologies like extendible masts or formation flight have been studied to go beyond this limit. To gain a better understanding of these telescopes, I detail the Wolter-I mirror geometry, their coating reflectivity, the detection in semi-conductor as well as the dynamic related to extendible masts and formation flight. These telescopes are complex optical systems, subject to deformations during observation and need a fine metrology system to measure these deformations for image correction. To study their performance, I developed a code reproducing the real functioning of such a telescope. Each photon is considered individually, its path and interactions depend on the behavior of the telescope structure along with time. Each component of the telescope is modeled, as well as the metrology needed for the restitution of its dynamic. The path of the photon is computed in a three dimensional vector space, using Monte-Carlo methods to reproduce the mirror defaults, their reflectivity and the interactions in the detector. The simulation produces images and energy spectra, from which we can infer the angular resolution, the field of view, the effective area and the detection efficiency. In 2006, the Simbol-X mission was selected in the framework of the formation flight studies. This concept allows a large focal length, the telescope being distributed on two independent spacecrafts

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

Science.gov (United States)

Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

2009-05-01

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

International Nuclear Information System (INIS)

Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

2009-01-01

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

The High Energy Detector of Simbol-X

Science.gov (United States)

Meuris, A.; Limousin, O.; Lugiez, F.; Gevin, O.; Blondel, C.; Le Mer, I.; Pinsard, F.; Cara, C.; Goetschy, A.; Martignac, J.; Tauzin, G.; Hervé, S.; Laurent, P.; Chipaux, R.; Rio, Y.; Fontignie, J.; Horeau, B.; Authier, M.; Ferrando, P.

2009-05-01

The High Energy Detector (HED) is one of the three detection units on board the Simbol-X detector spacecraft. It is placed below the Low Energy Detector so as to collect focused photons in the energy range from 8 to 80 keV. It consists of a mosaic of 64 independent cameras, divided in 8 sectors. Each elementary detection unit, called Caliste, is the hybridization of a 256-pixel Cadmium Telluride (CdTe) detector with full custom front-end electronics into a unique component. The status of the HED design will be reported. The promising results obtained from the first micro-camera prototypes called Caliste 64 and Caliste 256 will be presented to illustrate the expected performance of the instrument.

The High Energy Detector of Simbol-X

International Nuclear Information System (INIS)

Meuris, A.; Limousin, O.; Blondel, C.; Le Mer, I.; Pinsard, F.; Cara, C.; Goetschy, A.; Martignac, J.; Laurent, P.; Chipaux, R.; Rio, Y.; Fontignie, J.; Horeau, B.; Ferrando, P.; Lugiez, F.; Gevin, O.; Tauzin, G.; Herve, S.; Authier, M.

2009-01-01

The High Energy Detector (HED) is one of the three detection units on board the Simbol-X detector spacecraft. It is placed below the Low Energy Detector so as to collect focused photons in the energy range from 8 to 80 keV. It consists of a mosaic of 64 independent cameras, divided in 8 sectors. Each elementary detection unit, called Caliste, is the hybridization of a 256-pixel Cadmium Telluride (CdTe) detector with full custom front-end electronics into a unique component. The status of the HED design will be reported. The promising results obtained from the first micro-camera prototypes called Caliste 64 and Caliste 256 will be presented to illustrate the expected performance of the instrument.

Bahasa, Simbol, dan Religi

OpenAIRE

Supriyadi, Supriyadi

1999-01-01

Manusia sering disebut sebagai makhluk sosial, makhluk berakal, makhluk berseni, dan sebagainya. Tulisan ini secara tidak langsung membicarakan manusia sebagai makhluk berbahasa, bersimbol, dan bereligi . Meskipun demikian, titik tolaknya bukan pada manusia itu sendiri, tetapi pada bahasa, simbol, dan religinya, terutama pada hubungan di antara ketiganya . Hubungan antara bahasa dan simbol tidak diragukan lagi karena bahasa merupakan jenis simbol . Demikian juga hubungan antara simbol dengan ...

Hard X-ray Emission from Galaxy Clusters Observed with INTEGRAL and Prospects for Simbol-X

Science.gov (United States)

Eckert, D.; Paltani, S.; Courvoisier, T. J.-L.

2009-05-01

Some galaxy clusters are known to contain a large population of relativistic electrons, which produce radio emission through synchrotron radiation. Therefore, it is expected that inverse-Compton scattering of the relativistic electrons with the CMB produce non-thermal emission which should be observable in the hard X-ray domain. Here we focus on the recent results by INTEGRAL, which shed a new light on the non-thermal emission thanks to its angular resolution and sensitivity in the hard X-ray range. We also present the exciting prospects in this field for Simbol-X, which will allow us to detect the non-thermal emission in a number of clusters and map the magnetic field throughout the intra-cluster medium.

Relativistic Jets on all Scales in Accreting Black Holes: Contributions from Simbol-X

Science.gov (United States)

Corbel, Stéphane

2009-05-01

In the last several years, multiwavelength observations of accreting black holes have allowed a general characterisation of black holes properties as they evolve along the course of their outburst cycles. Relativistic jets, in their multiple forms, have profoundly impacted our perception and understanding of emission processes in these systems. In these Proceedings, I will highlight some possible contributions from Simbol-X related to jets in accreting sources.

Relativistic Jets on all Scales in Accreting Black Holes: Contributions from Simbol-X

International Nuclear Information System (INIS)

Corbel, Stephane

2009-01-01

In the last several years, multiwavelength observations of accreting black holes have allowed a general characterisation of black holes properties as they evolve along the course of their outburst cycles. Relativistic jets, in their multiple forms, have profoundly impacted our perception and understanding of emission processes in these systems. In these Proceedings, I will highlight some possible contributions from Simbol-X related to jets in accreting sources.

Study of Background Rejection Systems for the IXO Mission.

Science.gov (United States)

Laurent, Philippe; Limousin, O.; Tatischeff, V.

2009-01-01

The scientific performances of the IXO mission will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. In APC, Paris, and CEA, Saclay, we got experience on these activities by conceiving and optimising in parallel the high energy detector and the active and passive background rejection system of the Simbol-X mission. Considering that this work may be naturally extended to other X-ray missions, we have initiated with CNES a R&D project on the study of background rejection systems mainly in view the IXO project. We will detail this activity in the poster.

The Simbol-X Perspective on the Physics of Quasar Outflows

Science.gov (United States)

Giustini, M.; Cappi, M.; Vignali, C.; Palumbo, G. G. C.; Fiore, F.; Malaguti, G.

2009-05-01

There is increasing evidence that quasar outflows may play a key role in providing the feedback between AGN/QSOs and their surrounding (and feeding) media, in regulating the central supermassive black hole growth and the galaxy formation and, on larger scales, in shaping the growth of cosmic structures (see e.g. [1]). X-ray observations of quasar outflows are crucial to probe their innermost parts and assess the global energetics entrained in the outflow by studying its most extreme (in terms of velocity, ionization state, mass outflow rate) phases. Simbol-X-with its high effective area in the Fe K energy band and above-will allow the detection and the characterization of powerful outflows in bright, nearby AGN and notably also in moderately faint AGN, thus shedding light on feedback processes in these objects.

Simbol-X Hard X-ray Focusing Mirrors: Results Obtained During the Phase A Study

Science.gov (United States)

Tagliaferri, G.; Basso, S.; Borghi, G.; Burkert, W.; Citterio, O.; Civitani, M.; Conconi, P.; Cotroneo, V.; Freyberg, M.; Garoli, D.; Gorenstein, P.; Hartner, G.; Mattarello, V.; Orlandi, A.; Pareschi, G.; Romaine, S.; Spiga, D.; Valsecchi, G.; Vernani, D.

2009-05-01

Simbol-X will push grazing incidence imaging up to 80 keV, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. The superb hard X-ray imaging capability will be guaranteed by a mirror module of 100 electroformed Nickel shells with a multilayer reflecting coating. Here we will describe the technogical development and solutions adopted for the fabrication of the mirror module, that must guarantee an Half Energy Width (HEW) better than 20 arcsec from 0.5 up to 30 keV and a goal of 40 arcsec at 60 keV. During the phase A, terminated at the end of 2008, we have developed three engineering models with two, two and three shells, respectively. The most critical aspects in the development of the Simbol-X mirrors are i) the production of the 100 mandrels with very good surface quality within the timeline of the mission, ii) the replication of shells that must be very thin (a factor of 2 thinner than those of XMM-Newton) and still have very good image quality up to 80 keV, iii) the development of an integration process that allows us to integrate these very thin mirrors maintaining their intrinsic good image quality. The Phase A study has shown that we can fabricate the mandrels with the needed quality and that we have developed a valid integration process. The shells that we have produced so far have a quite good image quality, e.g. HEW <~30 arcsec at 30 keV, and effective area. However, we still need to make some improvements to reach the requirements. We will briefly present these results and discuss the possible improvements that we will investigate during phase B.

Simbol-X Hard X-ray Focusing Mirrors: Results Obtained During the Phase A Study

International Nuclear Information System (INIS)

Tagliaferri, G.; Basso, S.; Civitani, M.; Conconi, P.; Cotroneo, V.; Pareschi, G.; Spiga, D.; Borghi, G.; Garoli, D.; Mattarello, V.; Orlandi, A.; Valsecchi, G.; Vernani, D.; Burkert, W.; Freyberg, M.; Hartner, G.; Citterio, O.; Gorenstein, P.; Romaine, S.

2009-01-01

Simbol-X will push grazing incidence imaging up to 80 keV, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. The superb hard X-ray imaging capability will be guaranteed by a mirror module of 100 electroformed Nickel shells with a multilayer reflecting coating. Here we will describe the technogical development and solutions adopted for the fabrication of the mirror module, that must guarantee an Half Energy Width (HEW) better than 20 arcsec from 0.5 up to 30 keV and a goal of 40 arcsec at 60 keV. During the phase A, terminated at the end of 2008, we have developed three engineering models with two, two and three shells, respectively. The most critical aspects in the development of the Simbol-X mirrors are i) the production of the 100 mandrels with very good surface quality within the timeline of the mission, ii) the replication of shells that must be very thin (a factor of 2 thinner than those of XMM-Newton) and still have very good image quality up to 80 keV, iii) the development of an integration process that allows us to integrate these very thin mirrors maintaining their intrinsic good image quality. The Phase A study has shown that we can fabricate the mandrels with the needed quality and that we have developed a valid integration process. The shells that we have produced so far have a quite good image quality, e.g. HEW < or approx. 30 arcsec at 30 keV, and effective area. However, we still need to make some improvements to reach the requirements. We will briefly present these results and discuss the possible improvements that we will investigate during phase B.

Powerful Radio Sources with Simbol-X: The Nucleus

Science.gov (United States)

Grandi, Paola

2009-05-01

The black holes in the hearts of bright elliptical galaxies are commonly observed to be associated with powerful relativistic jets. The mechanism by which material entering the accretion radius is converted into jet power remains the subject of much debate. At the same time, the interplay between the relativistic jet and the interstellar/intergalactic medium is the topic of intense discussions, being such knowledge essential for understanding the nature of the accretion process, galaxy formation and the growth of supermassive black holes. Simbol-X can play a fundamental role in addressing at least three important questions: I) the link between accretion and relativistic outflow at

Powerful Radio Galaxies with Simbol-X: the Nuclear Environment

Science.gov (United States)

Torresi, E.; Grandi, P.; Malaguti, G.; Palumbo, G. G. C.; Bianchin, V.

2009-05-01

Fanaroff & Riley type II radio galaxies (FRII) are complex objects. In particular FRII Narrow Line Radio Galaxies (NLRG), optically classified as High Excitation Galaxies (HEG) show X-ray spectra very similar to their radio-quiet counterparts, the Seyfert 2 galaxies. They show 2-10 keV continua heavily obscured (NH~1023-24 cm-2) and intense FeKα lines, typical cold matter reprocessing features. Moreover recent Chandra and XMM-Newton observations suggest that the soft X-ray emission of HEG and Seyfert 2 have a common origin from photoionized gas, reinforcing the idea that not only their nuclear engine but also the circumnuclear gas (at least the warm phase) are similar. On the contrary, our knowledge of NLRG HEG above 10 keV is very poor when compared to brighter Seyfert 2. As a consequence, the physical properties of the cold phase of the circumnuclear gas (possibly linked to a dusty torus) are largely unknown. Thanks to its high sensitivity up to 80 keV, Simbol-X will provide very accurate spectra and will allow a direct comparison between the NLRG and Seyfert 2 cold environments.

Hydrodynamic Simulation of the Cosmological X-Ray Background

Science.gov (United States)

Croft, Rupert A. C.; Di Matteo, Tiziana; Davé, Romeel; Hernquist, Lars; Katz, Neal; Fardal, Mark A.; Weinberg, David H.

2001-08-01

We use a hydrodynamic simulation of an inflationary cold dark matter model with a cosmological constant to predict properties of the extragalactic X-ray background (XRB). We focus on emission from the intergalactic medium (IGM), with particular attention to diffuse emission from warm-hot gas that lies in relatively smooth filamentary structures between galaxies and galaxy clusters. We also include X-rays from point sources associated with galaxies in the simulation, and we make maps of the angular distribution of the emission. Although much of the X-ray luminous gas has a filamentary structure, the filaments are not evident in the simulated maps because of projection effects. In the soft (0.5-2 keV) band, our calculated mean intensity of radiation from intergalactic and cluster gas is 2.3×10-12 ergs-1 cm-2 deg-2, 35% of the total softband emission. This intensity is compatible at the ~1 σ level with estimates of the unresolved soft background intensity from deep ROSAT and Chandra measurements. Only 4% of the hard (2-10 keV) emission is associated with intergalactic gas. Relative to active galactic nuclei flux, the IGM component of the XRB peaks at a lower redshift (median z~0.45) and spans a narrower redshift range, so its clustering makes an important contribution to the angular correlation function of the total emission. The clustering on the scales accessible to our simulation (0.1‧-10') is significant, with an amplitude roughly consistent with an extrapolation of recent ROSAT results to small scales. A cross-correlation analysis of the XRB against nearby galaxies taken from a simulated redshift survey also yields a strong signal from the IGM. Our conclusions about the soft background intensity differ from those of some recent papers that have argued that the expected emission from gas in galaxy, group, and cluster halos would exceed the observed background unless much of the gas is expelled by supernova feedback. We obtain reasonable compatibility with

How Simbol-X Will Reveal the Most Obscured High Energy Sources of our Galaxy

Science.gov (United States)

Chaty, S.

2009-05-01

The INTEGRAL satellite has revealed a major population of supergiant High Mass X-ray Binaries in our Galaxy, revolutionizing our understanding of binary systems and their evolution. This population, constituted of a compact object orbiting around a supergiant star, have unusual properties, either being extremely absorbed, or exhibiting very short flares. I will first describe the characteristics of these sources, that only intensive multi-wavelength observations have led us to disentangle, before showing that Simbol-X, thanks to its energy range and sensitivity, will allow us to go further in the understanding of these supergiant HMXBs.

A fast one-chip event-preprocessor and sequencer for the Simbol-X Low Energy Detector

Energy Technology Data Exchange (ETDEWEB)

Schanz, T., E-mail: schanz@astro.uni-tuebingen.d [Kepler Center for Astro- and Particlephysics, Institut fuer Astronomie und Astrophysik Tuebingen, Sand 1, 72076 Tuebingen (Germany); Tenzer, C., E-mail: tenzer@astro.uni-tuebingen.d [Kepler Center for Astro- and Particlephysics, Institut fuer Astronomie und Astrophysik Tuebingen, Sand 1, 72076 Tuebingen (Germany); Maier, D.; Kendziorra, E.; Santangelo, A. [Kepler Center for Astro- and Particlephysics, Institut fuer Astronomie und Astrophysik Tuebingen, Sand 1, 72076 Tuebingen (Germany)

2010-12-11

We present an FPGA-based digital camera electronics consisting of an Event-Preprocessor (EPP) for on-board data preprocessing and a related Sequencer (SEQ) to generate the necessary signals to control the readout of the detector. The device has been originally designed for the Simbol-X low energy detector (LED). The EPP operates on 64x64 pixel images and has a real-time processing capability of more than 8000 frames per second. The already working releases of the EPP and the SEQ are now combined into one Digital-Camera-Controller-Chip (D3C).

A fast one-chip event-preprocessor and sequencer for the Simbol-X Low Energy Detector

International Nuclear Information System (INIS)

Schanz, T.; Tenzer, C.; Maier, D.; Kendziorra, E.; Santangelo, A.

2010-01-01

We present an FPGA-based digital camera electronics consisting of an Event-Preprocessor (EPP) for on-board data preprocessing and a related Sequencer (SEQ) to generate the necessary signals to control the readout of the detector. The device has been originally designed for the Simbol-X low energy detector (LED). The EPP operates on 64x64 pixel images and has a real-time processing capability of more than 8000 frames per second. The already working releases of the EPP and the SEQ are now combined into one Digital-Camera-Controller-Chip (D3C).

44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

Science.gov (United States)

Renaud, M.; Terrier, R.; Trap, G.; Lebrun, F.; Decourchelle, A.; Vink, J.

2009-05-01

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44Ti γ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

International Nuclear Information System (INIS)

Renaud, M.; Terrier, R.; Lebrun, F.; Trap, G.; Decourchelle, A.; Vink, J.

2009-01-01

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44 Tiγ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

A fast one-chip event-preprocessor and sequencer for the Simbol-X Low Energy Detector

Science.gov (United States)

Schanz, T.; Tenzer, C.; Maier, D.; Kendziorra, E.; Santangelo, A.

2010-12-01

We present an FPGA-based digital camera electronics consisting of an Event-Preprocessor (EPP) for on-board data preprocessing and a related Sequencer (SEQ) to generate the necessary signals to control the readout of the detector. The device has been originally designed for the Simbol-X low energy detector (LED). The EPP operates on 64×64 pixel images and has a real-time processing capability of more than 8000 frames per second. The already working releases of the EPP and the SEQ are now combined into one Digital-Camera-Controller-Chip (D3C).

DynamiX, numerical tool for design of next-generation x-ray telescopes.

Science.gov (United States)

Chauvin, Maxime; Roques, Jean-Pierre

2010-07-20

We present a new code aimed at the simulation of grazing-incidence x-ray telescopes subject to deformations and demonstrate its ability with two test cases: the Simbol-X and the International X-ray Observatory (IXO) missions. The code, based on Monte Carlo ray tracing, computes the full photon trajectories up to the detector plane, accounting for the x-ray interactions and for the telescope motion and deformation. The simulation produces images and spectra for any telescope configuration using Wolter I mirrors and semiconductor detectors. This numerical tool allows us to study the telescope performance in terms of angular resolution, effective area, and detector efficiency, accounting for the telescope behavior. We have implemented an image reconstruction method based on the measurement of the detector drifts by an optical sensor metrology. Using an accurate metrology, this method allows us to recover the loss of angular resolution induced by the telescope instability. In the framework of the Simbol-X mission, this code was used to study the impacts of the parameters on the telescope performance. In this paper we present detailed performance analysis of Simbol-X, taking into account the satellite motions and the image reconstruction. To illustrate the versatility of the code, we present an additional performance analysis with a particular configuration of IXO.

DynamiX, numerical tool for design of next-generation x-ray telescopes

International Nuclear Information System (INIS)

Chauvin, Maxime; Roques, Jean-Pierre

2010-01-01

We present a new code aimed at the simulation of grazing-incidence x-ray telescopes subject to deformations and demonstrate its ability with two test cases: the Simbol-X and the International X-ray Observatory (IXO) missions. The code, based on Monte Carlo ray tracing, computes the full photon trajectories up to the detector plane, accounting for the x-ray interactions and for the telescope motion and deformation. The simulation produces images and spectra for any telescope configuration using Wolter I mirrors and semiconductor detectors. This numerical tool allows us to study the telescope performance in terms of angular resolution, effective area, and detector efficiency, accounting for the telescope behavior. We have implemented an image reconstruction method based on the measurement of the detector drifts by an optical sensor metrology. Using an accurate metrology, this method allows us to recover the loss of angular resolution induced by the telescope instability. In the framework of the Simbol-X mission, this code was used to study the impacts of the parameters on the telescope performance. In this paper we present detailed performance analysis of Simbol-X, taking into account the satellite motions and the image reconstruction. To illustrate the versatility of the code, we present an additional performance analysis with a particular configuration of IXO.

DynamiX, numerical tool for design of next-generation x-ray telescopes

Energy Technology Data Exchange (ETDEWEB)

Chauvin, Maxime; Roques, Jean-Pierre

2010-07-20

We present a new code aimed at the simulation of grazing-incidence x-ray telescopes subject to deformations and demonstrate its ability with two test cases: the Simbol-X and the International X-ray Observatory (IXO) missions. The code, based on Monte Carlo ray tracing, computes the full photon trajectories up to the detector plane, accounting for the x-ray interactions and for the telescope motion and deformation. The simulation produces images and spectra for any telescope configuration using Wolter I mirrors and semiconductor detectors. This numerical tool allows us to study the telescope performance in terms of angular resolution, effective area, and detector efficiency, accounting for the telescope behavior. We have implemented an image reconstruction method based on the measurement of the detector drifts by an optical sensor metrology. Using an accurate metrology, this method allows us to recover the loss of angular resolution induced by the telescope instability. In the framework of the Simbol-X mission, this code was used to study the impacts of the parameters on the telescope performance. In this paper we present detailed performance analysis of Simbol-X, taking into account the satellite motions and the image reconstruction. To illustrate the versatility of the code, we present an additional performance analysis with a particular configuration of IXO.

Simbol-X: a formation flight mission with an unprecedented imaging capability in the 0.5-80 keV energy band

Science.gov (United States)

Tagliaferri, Gianpiero; Ferrando, Philippe; Le Duigou, Jean-Michel; Pareschi, Giovanni; Laurent, Philippe; Malaguti, Giuseppe; Clédassou, Rodolphe; Piermaria, Mauro; La Marle, Olivier; Fiore, Fabrizio; Giommi, Paolo

2017-11-01

The discovery of X-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the Universe. In fact, the exploration of the X-ray sky during the 70s-90s has established X-ray astronomy as a fundamental field of astrophysics. Today, the emission from astrophysical sources is by large best known at energies below 10 keV. The main reason for this situation is purely technical since grazing incidence reflection has so far been limited to the soft X-ray band. Above 10 keV all the observations have been obtained with collimated detectors or coded mask instruments. To make a leap step forward in Xray astronomy above 10 keV it is necessary to extend the principle of focusing X ray optics to higher energies, up to 80 keV and beyond. To this end, ASI and CNES are presently studying the implementation of a X-ray mission called Simbol-X. Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to 80 keV and beyond, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This technological breakthrough will open a new highenergy window in astrophysics and cosmology. Here we will address the problematic of the development for such a distributed and deformable instrument. We will focus on the main performances of the telescope, like angular resolution, sensitivity and source localization. We will also describe the specificity of the calibration aspects of the payload distributed over two satellites and therefore in a not "frozen" configuration.

SEGMENTASI WARNA UNTUK EKSTRAKSI SIMBOL DAN KARAKTER PADA CITRA RAMBU LALU LINTAS

Directory of Open Access Journals (Sweden)

Aryuanto Sutedjo

2012-05-01

Full Text Available Penelitian ini membahas teknik segmentasi warna berbasis RGB Chromaticity Diagram ternormalisasi, untuk ekstraksi simbol dan karakter pada citra rambu lalu lintas. Teknik yang diusulkan adalah memisahkan warna biru pada latar belakang rambu petunjuk lalu lintas. Hal tersebut dilakukan dengan memanfaatkan histogram yang dikembangkan pada diagram kromatisitas untuk penentuan nilai ambang segmentasi secara otomatis. Selain itu, teknik morfologi citra dan proyeksi histogram digunakan untuk ekstraksi simbol dan karakter. Dari hasil eksperimen diperoleh bahwa teknik yang diusulkan dapat mengekstrak simbol dan karakter dengan rata-rata ekstraksi 97.3%. This research describes a normalized color segmentation technique based on RGB Chromaticity Diagram, for the extraction of symbols and characters in the image of the traffic signs. The proposed technique is to separate the blue color of the background traffic signs. This is done by using a histogram that was developed in the chromaticity diagram for the determination of the threshold value segmentation automatically. In addition, the image morphology technique and projection histogram are used for the extraction of symbols and characters. From the experimental results obtained that the proposed technique can extract symbols and characters with an average extraction is 97.3%.

A fast event preprocessor for the Simbol-X Low-Energy Detector

Science.gov (United States)

Schanz, T.; Tenzer, C.; Kendziorra, E.; Santangelo, A.

2008-07-01

The Simbol-X1 Low Energy Detector (LED), a 128 × 128 pixel DEPFET array, will be read out very fast (8000 frames/second). This requires a very fast onboard data preprocessing of the raw data. We present an FPGA based Event Preprocessor (EPP) which can fulfill this requirements. The design is developed in the hardware description language VHDL and can be later ported on an ASIC technology. The EPP performs a pixel related offset correction and can apply different energy thresholds to each pixel of the frame. It also provides a line related common-mode correction to reduce noise that is unavoidably caused by the analog readout chip of the DEPFET. An integrated pattern detector can block all invalid pixel patterns. The EPP has an internal pipeline structure and can perform all operation in realtime (< 2 μs per line of 64 pixel) with a base clock frequency of 100 MHz. It is utilizing a fast median-value detection algorithm for common-mode correction and a new pattern scanning algorithm to select only valid events. Both new algorithms were developed during the last year at our institute.

SIMBOL RAMA DAN EPOS RAMAYANA BAGI RAJA DAN MASYARAKAT JAWA

Directory of Open Access Journals (Sweden)

Wachid Eko Purwanto

2015-06-01

Full Text Available Epos Ramayana merupakan epos kuno yang ditulis dalam tujuh kanda terdiri atas 24.000 sloka. Di Jawa epos Ramayana pertama kali muncul secara lengkap dalam bentuk relief di Candi Lara Jonggrang yang dibangun sekitar tahun 782 hingga 872 M. Epos tua yang hidup di masyarakat Jawa ini pastilah mempunyai ajaran. Tokoh Rama sebagai tokoh utama merupakan simbol paling utama dalam epos ini. Berkait dengan simbol ajaran, tokoh Rama dalam epos Ramayana Jawa mempunyai fungsi bagi Raja Jawa dan masyarakat Jawa. Bagi raja simbol tokoh Rama memiliki tiga fungsi utama. Pertama sebagai fungsi spiritual. Kedua adalah fungsi legitimasi kekuasaan. Ketiga adalah fungsi pencitraan. Adapun bagi masyarakat Jawa, simbol tokoh Rama memiliki dua fungsi utama. Pertama adalah fungsi spiritual. Kedua adalah fungsi filosofis.

Non-thermal Processes in Colliding-wind Massive Binaries: the Contribution of Simbol-X to a Multiwavelength Investigation

Science.gov (United States)

De Becker, Michaël; Blomme, Ronny; Micela, Giusi; Pittard, Julian M.; Rauw, Gregor; Romero, Gustavo E.; Sana, Hugues; Stevens, Ian R.

2009-05-01

Several colliding-wind massive binaries are known to be non-thermal emitters in the radio domain. This constitutes strong evidence for the fact that an efficient particle acceleration process is at work in these objects. The acceleration mechanism is most probably the Diffusive Shock Acceleration (DSA) process in the presence of strong hydrodynamic shocks due to the colliding-winds. In order to investigate the physics of this particle acceleration, we initiated a multiwavelength campaign covering a large part of the electromagnetic spectrum. In this context, the detailed study of the hard X-ray emission from these sources in the SIMBOL-X bandpass constitutes a crucial element in order to probe this still poorly known topic of astrophysics. It should be noted that colliding-wind massive binaries should be considered as very valuable targets for the investigation of particle acceleration in a similar way as supernova remnants, but in a different region of the parameter space.

BUJUKAN BERWISATA KE BALI: SIMBOL-SIMBOL PROMOSI PARIWISATA FILM ‘EAT PRAY LOVE’

Directory of Open Access Journals (Sweden)

Rimalinda Lukitasari

2017-02-01

Full Text Available Film merupakan sebuah promosi pariwisata yang potensial sebab simbol dan makna dalam film memiliki kemampuan mempengaruhi respon penonton dan memotivasi mereka untuk mengunjungi lokasi yang ditampilkan. Indonesia juga telah mendapatkan manfaat promosi pariwisata sebagai hasil dari popularitas sebuah film, namun, kajian di bidang ini belum mendapatkan banyak perhatian. Penelitian ini ditujukan untuk mempelajari promosi pariwisata melalui film dengan menganalisis simbol dan makna dalam film ‘Eat Pray Love’ yang menghadirkan daya tarik rasional, emosional, dan moral. Analisis dilaksanakan dengan menggunakan metode kualitatif dan menerapkan teori semiotika. Hasil penelitian menunjukkan bahwa atmosfer Bali ditangkap dengan baik dalam film, sehingga memberikan beberapa petunjuk mengenai Bali sebagai tempat tujuan wisata yang baik. Petunjuk-petunjuk ini terdiri dari daya tarik rasional, emosional, dan moral. Daya tarik rasional dalam film berhubungan dengan manfaat sensorik, keamanan, kebersihan, dan aksesibilitas yang baik. Daya tarik emosional memberikan pandangan Bali sebagai destinasi yang menenangkan, indah, romantis, dan ramah. Daya tarik moral memperlihatkan dorongan untuk datang ke Bali untuk menemukan bimbingan menuju keseimbangan spiritual.

Development of the Simbol-X science verification model and its contribution for the IXO Mission

Science.gov (United States)

Maier, Daniel; Aschauer, Florian; Dick, Jürgen; Distratis, Giuseppe; Gebhardt, Henry; Herrmann, Sven; Kendziorra, Eckhard; Lauf, Thomas; Lechner, Peter; Santangelo, Andrea; Schanz, Thomas; Strüder, Lothar; Tenzer, Chris; Treis, Johannes

2010-07-01

Like the International X-ray Observatory (IXO) mission, the Simbol-X mission is a projected X-ray space telescope with spectral and imaging capabilities covering the energy range from 500 eV up to 80 keV. To detect photons within this wide range of energies, a silicon based "Depleted P-channel Field Effect Transistor" (DePFET)- matrix is used as the Low Energy Detector (LED) on top of an array of CdTe-Caliste modules, which act as the High Energy Detector (HED). A Science Verification Model (SVM) consisting of one LED quadrant in front of one Caliste module will be set up at our institute (IAAT) and operated under laboratory conditions that approximate the expected environment in space. As a first step we use the SVM to test and optimize the performance of the LED operation and data acquisition chain, consisting of an ADC, an event-preprocessor, a sequencer, and an interface controller. All these components have been developed at our institute with the objective to handle the high readout rate of approximately 8000 frames per second. The second step is to study the behaviour and the interactions of LED and HED operating as a combined detector system. We report on the development status of the SVM and its associated electronics and present first results of the currently achieved spectral performance.

Non Thermal Emission from Clusters of Galaxies: the Importance of a Joint LOFAR/Simbol-X View

Science.gov (United States)

Ferrari, C.

2009-05-01

Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources (``halos'' and ``relics'') related to the presence of relativistic electrons and weak magnetic fields in the intracluster volume. I will outline our current knowledge about the presence and properties of this non-thermal cluster component. Despite the recent progress made in observational and theoretical studies of the non-thermal emission in galaxy clusters, a number of open questions about its origin and its effects on the thermo-dynamical evolution of galaxy clusters need to be answered. I will show the importance of combining galaxy cluster observations by new-generation instruments such as LOFAR and Simbol-X. A deeper knowledge of the non-thermal cluster component, together with statistical studies of radio halos and relics, will allow to test the current cluster formation scenario and to better constrain the physics of large scale structure evolution.

Non Thermal Emission from Clusters of Galaxies: the Importance of a Joint LOFAR/Simbol-X View

International Nuclear Information System (INIS)

Ferrari, C.

2009-01-01

Deep radio observations of galaxy clusters have revealed the existence of diffuse radio sources ('halos' and 'relics') related to the presence of relativistic electrons and weak magnetic fields in the intracluster volume. I will outline our current knowledge about the presence and properties of this non-thermal cluster component. Despite the recent progress made in observational and theoretical studies of the non-thermal emission in galaxy clusters, a number of open questions about its origin and its effects on the thermo-dynamical evolution of galaxy clusters need to be answered. I will show the importance of combining galaxy cluster observations by new-generation instruments such as LOFAR and Simbol-X. A deeper knowledge of the non-thermal cluster component, together with statistical studies of radio halos and relics, will allow to test the current cluster formation scenario and to better constrain the physics of large scale structure evolution.

SIMBOL test facility. Safety aspects. Amended version; SIMBOL experimenteerfaciliteit. Veiligheidsaspecten. Geamendeerde versie

Energy Technology Data Exchange (ETDEWEB)

Schoonewelle, H.

1995-12-01

A detailed description is given of the bubble chamber SIMBOL at the HOR reactor in Delft, Netherlands, including drawings, applied materials and dimensions. Attention is paid to the nuclear and radiological aspects of the installation and an overview is given of the procedures for the realization, the testing and the operational safety of the chamber. Also the results of a failure and accident analysis are presented. Finally, the dismantlement aspects are dealt with. 5 appendices, 12 refs.

JEM-X background models

DEFF Research Database (Denmark)

Huovelin, J.; Maisala, S.; Schultz, J.

2003-01-01

Background and determination of its components for the JEM-X X-ray telescope on INTEGRAL are discussed. A part of the first background observations by JEM-X are analysed and results are compared to predictions. The observations are based on extensive imaging of background near the Crab Nebula...... on revolution 41 of INTEGRAL. Total observing time used for the analysis was 216 502 s, with the average of 25 cps of background for each of the two JEM-X telescopes. JEM-X1 showed slightly higher average background intensity than JEM-X2. The detectors were stable during the long exposures, and weak orbital...... background was enhanced in the central area of a detector, and it decreased radially towards the edge, with a clear vignetting effect for both JEM-X units. The instrument background was weakest in the central area of a detector and showed a steep increase at the very edges of both JEM-X detectors...

Background in xenon filled X-ray detectors

International Nuclear Information System (INIS)

Feroci, M.; Costa, E.; Dwyer, J.; Ford, E.; Kaaret, P.; Rapisarda, M.; Soffitta, P.

1995-01-01

Xenon based gas mixtures have been often used in proportional counters for X-ray astronomy in order to achieve a good efficiency in the medium/high X-ray energy range. Proportional counters flown on past missions (i.e. HEAO1 and EXOSAT) filled with Xe-based mixtures have shown a higher residual background (after that all the rejection techniques have been applied) with respect to Ar-based ones, operating in the same energy band and in the same radiation environment. We show, by means of Monte Carlo simulations, analytical computations and laboratory measurements, that such difference can be mostly understood in terms of higher internal background production and lower pulse discrimination efficiency in Xe-based gas filling, with respect to Ar-based ones. (orig.)

Makna Simbol Kebudayaan Minangkabau Dalam Novel Tenggelamnya Kapal Van Der Wijck Karya Hamka: Tinjauan Semiotika

OpenAIRE

Akhyar, Aqmarul

2017-01-01

100701001 Penelitian ini dilatarbelakangi oleh roman Tenggelamna Kapal van der Wijck (TKvDW) karya Hamka yang menyajikan unsur-unsur adat Minangkabau dengan sangat kental, kokoh serta dianut oleh masyarakat Minangkabau. Tujuan penelitian ini adalah menginventarisasi bentuk simbol kebudayaan Minangkabau dan menganalisis makna simbol kebudayaan Minangkabau dalam roman TKvDW. Metode penelitian yang digunakan adalah metode penelitian kualitatif dan kepustakaan (library research). Teknik pengum...

Modeling of proton-induced radioactivation background in hard X-ray telescopes: Geant4-based simulation and its demonstration by Hitomi's measurement in a low Earth orbit

Science.gov (United States)

Odaka, Hirokazu; Asai, Makoto; Hagino, Kouichi; Koi, Tatsumi; Madejski, Greg; Mizuno, Tsunefumi; Ohno, Masanori; Saito, Shinya; Sato, Tamotsu; Wright, Dennis H.; Enoto, Teruaki; Fukazawa, Yasushi; Hayashi, Katsuhiro; Kataoka, Jun; Katsuta, Junichiro; Kawaharada, Madoka; Kobayashi, Shogo B.; Kokubun, Motohide; Laurent, Philippe; Lebrun, Francois; Limousin, Olivier; Maier, Daniel; Makishima, Kazuo; Mimura, Taketo; Miyake, Katsuma; Mori, Kunishiro; Murakami, Hiroaki; Nakamori, Takeshi; Nakano, Toshio; Nakazawa, Kazuhiro; Noda, Hirofumi; Ohta, Masayuki; Ozaki, Masanobu; Sato, Goro; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Tanaka, Takaaki; Tanaka, Yasuyuki; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yamaoka, Kazutaka; Yasuda, Tetsuya; Yatsu, Yoichi; Yuasa, Takayuki; Zoglauer, Andreas

2018-05-01

Hard X-ray astronomical observatories in orbit suffer from a significant amount of background due to radioactivation induced by cosmic-ray protons and/or geomagnetically trapped protons. Within the framework of a full Monte Carlo simulation, we present modeling of in-orbit instrumental background which is dominated by radioactivation. To reduce the computation time required by straightforward simulations of delayed emissions from activated isotopes, we insert a semi-analytical calculation that converts production probabilities of radioactive isotopes by interaction of the primary protons into decay rates at measurement time of all secondary isotopes. Therefore, our simulation method is separated into three steps: (1) simulation of isotope production, (2) semi-analytical conversion to decay rates, and (3) simulation of decays of the isotopes at measurement time. This method is verified by a simple setup that has a CdTe semiconductor detector, and shows a 100-fold improvement in efficiency over the straightforward simulation. To demonstrate its experimental performance, the simulation framework was tested against data measured with a CdTe sensor in the Hard X-ray Imager onboard the Hitomi X-ray Astronomy Satellite, which was put into a low Earth orbit with an altitude of 570 km and an inclination of 31°, and thus experienced a large amount of irradiation from geomagnetically trapped protons during its passages through the South Atlantic Anomaly. The simulation is able to treat full histories of the proton irradiation and multiple measurement windows. The simulation results agree very well with the measured data, showing that the measured background is well described by the combination of proton-induced radioactivation of the CdTe detector itself and thick Bi4Ge3O12 scintillator shields, leakage of cosmic X-ray background and albedo gamma-ray radiation, and emissions from naturally contaminated isotopes in the detector system.

Evolution of Cygnus X-3 through its Radio and X-ray States

International Nuclear Information System (INIS)

Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

2009-01-01

Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

Evolution of Cygnus X-3 through its Radio and X-ray States

Science.gov (United States)

Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

2009-05-01

Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

Study of new anticoincidence systems design

International Nuclear Information System (INIS)

Chabaud, J.; Laurent, P.; Baronick, J.-P.; Oger, R.; Prévôt, G.

2012-01-01

The scientific performances of future hard X-ray missions will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. We got experience on these activities by conceiving and optimizing the active and passive background rejection system of the Simbol-X and IXO/HXI missions. Considering that this work may naturally be extended to other X-ray missions, we have initiated with CNES, in 2010, a R and T project on the study of background rejection systems, whose status will be presented in this paper.

Study of new anticoincidence systems design

Science.gov (United States)

Chabaud, J.; Laurent, P.; Baronick, J.-P.; Oger, R.; Prévôt, G.

2012-12-01

The scientific performances of future hard X-ray missions will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. We got experience on these activities by conceiving and optimizing the active and passive background rejection system of the Simbol-X and IXO/HXI missions. Considering that this work may naturally be extended to other X-ray missions, we have initiated with CNES, in 2010, a R&T project on the study of background rejection systems, whose status will be presented in this paper.

Study of new anticoincidence systems design

Energy Technology Data Exchange (ETDEWEB)

Chabaud, J., E-mail: chabaud@apc.univ-paris7.fr [Laboratoire APC, 10 rue Alice Domon et Leonie Duquet, F-75205, Paris Cedex 13 (France); Laurent, P. [Laboratoire APC, 10 rue Alice Domon et Leonie Duquet, F-75205, Paris Cedex 13 (France); CEA DSM/IRFU/SAp-Service d' Astrophysique, F-91191, Gif sur Yvette (France); Baronick, J.-P.; Oger, R.; Prevot, G. [Laboratoire APC, 10 rue Alice Domon et Leonie Duquet, F-75205, Paris Cedex 13 (France)

2012-12-11

The scientific performances of future hard X-ray missions will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. We got experience on these activities by conceiving and optimizing the active and passive background rejection system of the Simbol-X and IXO/HXI missions. Considering that this work may naturally be extended to other X-ray missions, we have initiated with CNES, in 2010, a R and T project on the study of background rejection systems, whose status will be presented in this paper.

Origin of the cosmic x-ray background

International Nuclear Information System (INIS)

Margon, B.

1983-01-01

Since 1962, it has been known that every part of the sky emits a uniform glow of x-rays. After two decades of intense study the origin of this diffuse x-ray background is still a subject of controversy. The near perfect isotropy of the x-ray background is clearly a vital clue to its origin. A second clue to the origin of the x-ray background arises from the fact that it is x-radiation tha is generated, rather than some longer wavelength radiation. Two hypotheses of the origin of this x-ray background are discussed. One hypothesis is that the x-ray background can be attributed to bremsstrahlung from a hot intergalactic medium. The second hypothesis is that the x-ray background originates from a large number of quasars. Because there is no estimate independent of the intensity of the x-ray background of how much hot intergalactic medium exists (if any), there is a real possibility that both sources contribute to the observed x-rays. (SC)

Blazars in Hard X-rays

Science.gov (United States)

Ghisellini, Gabriele

2009-05-01

Although blazars are thought to emit most of their luminosity in the γ-ray band, there are subclasses of them very prominent in hard X-rays. These are the best candidates to be studied by Simbol-X. They are at the extremes of the blazar sequence, having very small or very high jet powers. The former are the class of TeV emitting BL Lacs, whose synchrotron emission often peaks at tens of keV or more. The latter are the blazars with the most powerful jets, have high black hole masses accreting at high (i.e. close to Eddington) rates. These sources are predicted to have their high energy peak even below the MeV band, and therefore are very promising candidates to be studied with Simbol-X.

Restablished Accretion in Post-outburst Classical Novae Revealed by X-rays

Science.gov (United States)

Hernanz, Margarita; Ferri, Carlo; Sala, Glòria

2009-05-01

Classical novae are explosions on accreting white dwarfs (hereinafter WDs) in cataclysmic variables (hereinafter CVs) a hydrogen thermonuclear runaway on top of the WD is responsible for the outburst. X-rays provide a unique way to study the turn-off of H-burning, because super soft X-rays reveal the hot WD photosphere, but also to understand how accretion is established again in the binary system. Observations with XMM-Newton of some post-outburst novae have revealed such a process, but a coverage up to larger energies -as Simbol-X will provide- is fundamental to well understand the characteristics of the binary system and of the nova ejecta. We present a brief summary of our results up to now and prospects for the Simbol-X mission.

Miskonsepsi Buku Ajar Fisika SMA Kelas X Pada Pokok Bahasan Dinamika Gerak

Directory of Open Access Journals (Sweden)

Fachmi Nurdiansyah

2018-03-01

Full Text Available Penelitian ini bertujuan untuk memaparkan bentuk-bentuk miskonsepsi pada pokok bahasan dinamika gerak dalam buku ajar fisika SMA kelas X. Adapun buku ajar yang digunakan dalam penelitian ini, yaitu: (1 Fisika untuk SMA/MA Kelas X Semester I karangan RA dan SI yang diterbitkan tahun 2012 oleh penerbit IP, (2 Fisika untuk SMA/MA Kelas X Semester I karangan TPM yang diterbitkan tahun 2013 oleh penerbit VP, dan (3 Fisika Peminatan untuk SMA/MA Kelas X karangan SN dan SZ yang diterbitkan tahun 2013 oleh penerbit YW. Penelitian ini merupakan penelitian kualitatif deskriptif. Objek dalam penelitian ini adalah data berupa aspek penjelasan konsep, penulisan rumus, penulisan simbol, penulisan satuan, dan penyajian gambar pada pokok bahasan dinamika gerak dalam buku ajar fisika SMA. Penelitian dilakukan dengan cara menganalisis data dalam buku ajar fisika SMA yang dibandingkan dengan buku teks fisika universitas. Berdasarkan analisis data yang telah dilakukan, dapat disimpulkan bahwa miskonsepsi pada pokok bahasan dinamika gerak terdapat dalam buku ajar fisika SMA. Buku ajar IP mengalami miskonsepsi pada aspek penjelasan konsep dengan persentase 10%, penulisan rumus dengan persentase 57,14%, penulisan simbol dengan persentase 46,15%, dan penyajian gambar dengan persentase 20%. Buku ajar VP mengalami miskonsepsi pada aspek penjelasan konsep dengan persentase 10%, penulisan rumus dengan persentase 85,71%, penulisan simbol dengan persentase 79,62%, dan penyajian gambar dengan persentase 80%. Buku ajar YW mengalami miskonsepsi pada aspek penjelasan konsep dengan persentase 10%, penulisan rumus dengan persentase 85,71%, penulisan simbol dengan persentase 69,23, dan penyajian gambar dengan persentase 20%. Pada aspek penulisan satuan, tidak terdapat miskonsepsi dalam buku ajar IP, VP, dan YW.

Galaxies in the X-ray Band

Science.gov (United States)

Hornschemeier, Ann

2008-01-01

This talk will provide a brief review of progress on X-ray emission from normal (non-AGN) galaxy populations, including important constraints on the evolution of accreting binary populations over important cosmological timescales. We will also look to the future, anticipating constraints from near-term imaging hard X-ray missions such as NuSTAR, Simbol-X and NeXT and then the longer-term prospects for studying galaxies with the Generation-X mission.

Nilai Interaksi Simbol Tradisi dalam Wujud Pelinggih pada Ruang Publik

Directory of Open Access Journals (Sweden)

I Nyoman Larry Julianto

2016-01-01

Full Text Available ABSTRACT   In public space in North Bali, there has been concept  change  of symbol tradition  visualiza- tion in the form of pelinggih  which is in the form  of car. But its essential function as a place  of worship has not changed. The surrounding  community  can accept that phenomenon as adop- tion process and identity  of cultural heritage. Through qualitative  research, try to be understood  a ‘creative  process’ outside ‘context  of the self’ in communicating  the message through  visual media. From this research stated that visual form of pelinggih  not only the expression result of beauty,  but also to communicate  the message. Ritual principles  of a pelinggih is still maintained.  Its materialization  concept has undergonenovelty  identity  due to unification  of aesthetic  value, art, spiritual and ‘moderniza- tion’ in the context  of ‘worldly’  life. Symbol  visualization  in an effort to communicate  that message,  contains  elements  of cultural system  acculturation   of today’s society to mutually  in- teract.   Keywords: symbol tradition,  visual change,  identity  of novelty,  public  space   ABSTRAK   Pada ruang publik di Bali Utara, terjadi perubahan konsep visualisasi simbol tradisi dalam wujud pelinggih, yakni berbentuk mobil. Fungsi esensinya sebagai tempat pemujaan tidak berubah. Masyarakat sekitar dapat menerima fenomena tersebut sebagai proses adopsi dan identitas warisan budaya. Melalui penelitian kualitatif, berupaya dipahami sebuah ‘proses kreatif’ diluar ‘konteks diri’ dalam mengomunikasikan pesan melalui media visual. Dari penelitian ini, dinyatakan bahwa wujud visual pelinggih tidak hanya hasil ekspresi keindahan, tetapi juga mengomunikasikan pesan. Prinsip–prinsip ritual sebuah pelinggih tetap dipertahankan. Konsep perwujudannya mengalami identitas kebaruan akibat dari penyatuan nilai estetis, seni, spiritual serta ‘modernisasi’ dalam

Background simulations for the Large Area Detector onboard LOFT

DEFF Research Database (Denmark)

Campana, Riccardo; Feroci, Marco; Ettore, Del Monte

2013-01-01

and magnetic fields around compact objects and in supranuclear density conditions. Having an effective area of similar to 10 m(2) at 8 keV, LOFT will be able to measure with high sensitivity very fast variability in the X-ray fluxes and spectra. A good knowledge of the in-orbit background environment...... is essential to assess the scientific performance of the mission and optimize the design of its main instrument, the Large Area Detector (LAD). In this paper the results of an extensive Geant-4 simulation of the instrumentwillbe discussed, showing the main contributions to the background and the design...... an anticipated modulation of the background rate as small as 10 % over the orbital timescale. The intrinsic photonic origin of the largest background component also allows for an efficient modelling, supported by an in-flight active monitoring, allowing to predict systematic residuals significantly better than...

X-ray scattering in X-ray fluorescence spectra with X-ray tube excitation - Modelling, experiment, and Monte-Carlo simulation

International Nuclear Information System (INIS)

Hodoroaba, V.-D.; Radtke, M.; Vincze, L.; Rackwitz, V.; Reuter, D.

2010-01-01

X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The knowledge of the X-ray spectrometer efficiency, but also of the spectrometer response functions makes it possible to define a physical spectral background of XRF spectra. Background subtraction relying on purely mathematical procedures is state-of-the-art. The results produced by the analytical model are at least as reliable as those obtained by Monte-Carlo simulations, even without considering the very challenging contribution of multiple scattering. Special attention has been paid to Compton broadening. Relevant applications of the implementation of the analytical model presented in this paper are the prediction of the limits of detection for particular cases or the determination of the transmission of X-ray polycapillary lenses.

The background simulations for the integral X-ray monitor JEM-X

DEFF Research Database (Denmark)

Feroci, M.; Rapisarda, M.; Costa, E.

1999-01-01

The JEM-X experiment (Joint European X-ray Monitor, Lund et al. (1998) and Westergaard and Lund (1998)) is the X-ray monitor of the INTEGRAL satellite. It is a coded aperture, high pressure microstrip proportional counter. It will operate in the primary energy range from 3 to 35 keV (with...

Hard X-ray emission from accretion shocks around galaxy clusters

Science.gov (United States)

Kushnir, Doron; Waxman, Eli

2010-02-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being lesssim0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Hard X-ray emission from accretion shocks around galaxy clusters

Energy Technology Data Exchange (ETDEWEB)

Kushnir, Doron; Waxman, Eli, E-mail: doron.kushnir@weizmann.ac.il, E-mail: eli.waxman@weizmann.ac.il [Physics Faculty, Weizmann Institute of Science, PO Box 26, Rehovot (Israel)

2010-02-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being ∼<0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Hard X-ray emission from accretion shocks around galaxy clusters

International Nuclear Information System (INIS)

Kushnir, Doron; Waxman, Eli

2010-01-01

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being ∼<0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) γ-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed

Modelling of Ne-like copper X-ray laser driven by 1.2 ps short pulse and 280 ps background pulse configuration

International Nuclear Information System (INIS)

Demir, A.; Kenar, N.; Goktas, H.; Tallents, G.J.

2004-01-01

Detailed simulations of Ne-like Cu x-ray laser are undertaken using the EHYBRID code. The atomic physics data are obtained using the Cowan code. The optimization calculations are performed in terms of the intensity of background and the time separation between the background and the short pulse. The optimum value is obtained for the conditions of a Nd:glass laser with 1.2 ps pulse at 4.4 x 10 15 W cm -2 irradiance pumping a plasma pre-formed by a 280 ps duration pulse at 5.4 x 10 12 W cm -2 with peak-to-peak pulse separation set at 300 ps. X-ray resonance lines between 6 A and 15 A emitted from copper plasmas have been simulated. Free-free and free-bound emission from the Si-, Al-, Mg-, Na-, Ne- and F-like ions is calculated in the simulation. (author)

Simulation of off-energy electron background in DELPHI

CERN Document Server

Falk, E; Von Holtey, Georg

1997-01-01

Monte Carlo simulations of off-energy electron background in the DELPHI luminometer STIC are reported. The study simulates the running conditions at 68 GeV with and without bunch trains. The electrostatic separators, which create the vertical separation bumps for the the bunch trains, cause a high concentration of background in the vertical plane. The simulations are compared to LEP data taken under similar running conditions. A comparison between the simulated running conditions at 68 GeV and those of the new LEP2 beam optics at 80.5 GeV is made. Moreover, the study investigates background components entering STIC elsewhere that through the front of the detector, and a significant portion is found to enter either from the back or from below. Possible improvements of the background situation are also discussed.

Simbol Dalam Upacara Adat Dayak Ngaju (Symbols in Ritual Tribe of Dayak Ngaju)

OpenAIRE

Kuenna, Kuenna

2015-01-01

Simbol dalam Upacara Adat Dayak Ngaju. Upacara adat adalah bentuk kebaktian masyarakat DayakNgaju terhadap Ranying Hatalla (Tuhan), dewa-dewa, roh nenek moyang atau mahluk halus lainnya,dan dalam USAhanya untuk berkomunikasi dengan Tuhan dan mahluk gaib lainnya untuk memperolehkehidupan yang sejahtera. Penelitian ini penting diteliti guna melestarikan budaya masyarakat DayakNgaju sebelum budaya itu sendiri mengalami kepunahan. Tujuan penelitian ini untuk mendeskripsikan180wujud, makna, dan fu...

Quasars: Cosmological evolution and x-ray background contribution

International Nuclear Information System (INIS)

Schmidt, M.; Green, R.F.

1986-01-01

The luminosity function of quasars varies with redshift or cosmic epoch. The authors discuss how the luminosity function and its evolution can be determined from complete samples of quasars. They first concentrate on optical survey of quasars. For quasars of medium luminosity, the co-moving space density rises very steeply with redshift. Quasars of lower luminosity exhibit a slower increase of density with redshift, resulting in luminosity-dependent evolution of the space density. They also discuss evidence for a cutoff of quasar redshift and for a possible dependence of the cutoff on luminosity. They evaluate X-ray counts of quasars and show the need for negative X-ray luminosity evolution in order to explain the counts and the low average redshifts of X-ray quasars. As a consequence, the quasar contribution to the X-ray background is lower than originally suspected. They discuss other extragalactic contributors to the X-ray background and conclude that they, together with the quasars, contribute about 60 percent of the observed background. About half of this is contributed by active galactic nuclei with optical luminosities below those of quasars

Background radiation in inelastic X-ray scattering and X-ray emission spectroscopy. A study for Johann-type spectrometers

Science.gov (United States)

Paredes Mellone, O. A.; Bianco, L. M.; Ceppi, S. A.; Goncalves Honnicke, M.; Stutz, G. E.

2018-06-01

A study of the background radiation in inelastic X-ray scattering (IXS) and X-ray emission spectroscopy (XES) based on an analytical model is presented. The calculation model considers spurious radiation originated from elastic and inelastic scattering processes along the beam paths of a Johann-type spectrometer. The dependence of the background radiation intensity on the medium of the beam paths (air and helium), analysed energy and radius of the Rowland circle was studied. The present study shows that both for IXS and XES experiments the background radiation is dominated by spurious radiation owing to scattering processes along the sample-analyser beam path. For IXS experiments the spectral distribution of the main component of the background radiation shows a weak linear dependence on the energy for the most cases. In the case of XES, a strong non-linear behaviour of the background radiation intensity was predicted for energy analysis very close to the backdiffraction condition, with a rapid increase in intensity as the analyser Bragg angle approaches π / 2. The contribution of the analyser-detector beam path is significantly weaker and resembles the spectral distribution of the measured spectra. Present results show that for usual experimental conditions no appreciable structures are introduced by the background radiation into the measured spectra, both in IXS and XES experiments. The usefulness of properly calculating the background profile is demonstrated in a background subtraction procedure for a real experimental situation. The calculation model was able to simulate with high accuracy the energy dependence of the background radiation intensity measured in a particular XES experiment with air beam paths.

Exploring the Hard and Soft X-ray Emission of Magnetic Cataclysmic Variables

Science.gov (United States)

de Martino, D.; Anzolin, G.; Bonnet-Bidaud, J.-M.; Falanga, M.; Matt, G.; Mouchet, M.; Mukai, K.; Masetti, N.

2009-05-01

A non-negligible fraction of galactic hard (>20 keV) X-ray sources were identified as CVs of the magnetic Intermediate Polar type in INTEGRAL, SWIFT and RXTE surveys, that suggests a still hidden but potentially important population of faint hard X-ray sources. Simbol-X has the unique potential to simultaneously characterize their variable and complex soft and hard X-ray emission thus allowing to understand their putative role in galactic populations of X-ray sources.

Simulation of Experimental Background using FLUKA

Energy Technology Data Exchange (ETDEWEB)

Rokni, Sayed

1999-05-11

In November 1997, Experiment T423 began acquiring data with the intentions of understanding the energy spectra of high-energy neutrons generated in the interaction of electrons with lead. The following describes a series of FLUKA simulations studying (1) particle yields in the absence of all background; (2) the background caused from scattering in the room; (3) the effects of the thick lead shielding which surrounded the detector; (4) the sources of neutron background created in this lead shielding; and (5) the ratio of the total background to the ideal yield. In each case, particular attention is paid to the neutron yield.

ESTETIKA DAN SIMBOL DALAM WUWUNGAN MAYONGLOR SEBAGAI WUJUD SPIRITUAL MASYARAKAT

Directory of Open Access Journals (Sweden)

Eko Darmawanto

2015-05-01

Full Text Available Wuwungan merupakan bentuk simbol yang mewakili sebuah maksud yang ingin wujudkan melalui material baik bersifat aplikatif ataupun bersifat murni estetis. Bentuk yang terangkum dalam wuwungan merupakan salah satu wujud yang merepresentasikan hal tersebut akan tetapi masih banyak kajian yang harus ditelusuri terlebih karya wuwungan merupakan bentuk yang merepresentasikan percampuran budaya. Pola konstruksi, bentuk serta implementatif terhadap atap bangunan adalah sistem yang perlu dibedah, dikaji dan dikomparasikan sebagai wujud untuk mengetahui seberapa jauh terkait antara unsur spritual, masyarakat dan pengguna wuwungan. Kualitatif merupakan metode yang peneliti gunakan dengan pendekatan formalitas yang melihat sosok sebagai fokus utamanya. Wuwungan Mayonglor merupakan gambaran kreasi imajinatif dari alam pikiran tidak sadar dan dituangkan dengan bentuk simbol dengan mengusung estetis dimana keindahan bersifat terpusat atau berakar dari tuhan penyatuan antara makrokosmos dan mikrokosmos atau salah satu diantaranya sebagai wujud ungkapan spiritual masyarakatnya.Wuwungan are symbols that represent a purpose to be realized trough both object are aplicable and are purely aesthetic. form are summarized in wuwungan is one of manifestation are display it, but still many of studies should explore first to know wuwungan is a form that represents the meaning of culture.patern of shape and construction of the building are implementable system that need to be studied and dissected olso compare as form to find out how much related between the spiritual element of the wuwungan user and society. Kualitatif research is a method used with formalities approach to see form as the main focus. Mayonglor wuwungan is an overview of imaginative creation of the mind is unconscious and poured symbolic form of engagement with the lifting aestetic where beauty is centralized or rooted in divine union of the macrocosm and micrososm or one of them as form of spiritual

The Emerging Population of Pulsar Wind Nebulae in Hard X-rays

Science.gov (United States)

Mattana, F.; Götz, D.; Terrier, R.; Renaud, M.; Falanga, M.

2009-05-01

The hard X-ray synchrotron emission from Pulsar Wind Nebulae probes energetic particles, closely related to the pulsar injection power at the present time. INTEGRAL has disclosed the yet poorly known population of hard X-ray pulsar/PWN systems. We summarize the properties of the class, with emphasys on the first hard X-ray bow-shock (CTB 80 powered by PSR B1951+32), and highlight some prospects for the study of Pulsar Wind Nebulae with the Simbol-X mission.

Investigation of the hard x-ray background in backlit pinhole imagers

Energy Technology Data Exchange (ETDEWEB)

Fein, J. R., E-mail: jrfein@umich.edu; Holloway, J. P. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States); Peebles, J. L. [Center for Energy Research, University of California, San Diego, La Jolla, California 92093 (United States); Keiter, P. A.; Klein, S. R.; Kuranz, C. C.; Manuel, M. J.-E.; Drake, R. P. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States)

2014-11-15

Hard x-rays from laser-produced hot electrons (>10 keV) in backlit pinhole imagers can give rise to a background signal that decreases signal dynamic range in radiographs. Consequently, significant uncertainties are introduced to the measured optical depth of imaged plasmas. Past experiments have demonstrated that hard x-rays are produced when hot electrons interact with the high-Z pinhole substrate used to collimate the softer He-α x-ray source. Results are presented from recent experiments performed on the OMEGA-60 laser to further study the production of hard x-rays in the pinhole substrate and how these x-rays contribute to the background signal in radiographs. Radiographic image plates measured hard x-rays from pinhole imagers with Mo, Sn, and Ta pinhole substrates. The variation in background signal between pinhole substrates provides evidence that much of this background comes from x-rays produced in the pinhole substrate itself. A Monte Carlo electron transport code was used to model x-ray production from hot electrons interacting in the pinhole substrate, as well as to model measurements of x-rays from the irradiated side of the targets, recorded by a bremsstrahlung x-ray spectrometer. Inconsistencies in inferred hot electron distributions between the different pinhole substrate materials demonstrate that additional sources of hot electrons beyond those modeled may produce hard x-rays in the pinhole substrate.

Preliminary background prediction for the INTEGRAL x-ray monitor

DEFF Research Database (Denmark)

Feroci, M.; Costa, E.; Budtz-Joergensen, C.

1996-01-01

The JEM-X (joint European x-ray monitor) experiment will be flown onboard the ESA's INTEGRAL satellite. The instrumental background level of the two JEM-X twin detectors will depend on several parameters, among which the satellite orbit and mass distribution, and the detectors materials play...

In-flight calibration of Hitomi Soft X-ray Spectrometer. (1) Background

Science.gov (United States)

Kilbourne, Caroline A.; Sawada, Makoto; Tsujimoto, Masahiro; Angellini, Lorella; Boyce, Kevin R.; Eckart, Megan E.; Fujimoto, Ryuichi; Ishisaki, Yoshitaka; Kelley, Richard L.; Koyama, Shu; Leutenegger, Maurice A.; Loewenstein, Michael; McCammon, Dan; Mitsuda, Kazuhisa; Nakashima, Shinya; Porter, Frederick S.; Seta, Hiromi; Takei, Yoh; Tashiro, Makoto S.; Terada, Yukikatsu; Yamada, Shinya; Yamasaki, Noriko Y.

2018-03-01

The X-Ray Spectrometer (XRS) instrument of Suzaku provided the first measurement of the non-X-ray background (NXB) of an X-ray calorimeter spectrometer, but the data set was limited. The Soft X-ray Spectrometer (SXS) instrument of Hitomi was able to provide a more detailed picture of X-ray calorimeter background, with more than 360 ks of data while pointed at the Earth, and a comparable amount of blank-sky data. These data are important not only for analyzing SXS science data, but also for categorizing the contributions to the NXB in X-ray calorimeters as a class. In this paper, we present the contributions to the SXS NXB, the types and effectiveness of the screening, the interaction of the screening with the broad-band redistribution, and the residual background spectrum as a function of magnetic cut-off rigidity. The orbit-averaged SXS NXB in the range 0.3-12 keV was 4 × 10-2 counts s-1 cm-2. This very low background in combination with groundbreaking spectral resolution gave SXS unprecedented sensitivity to weak spectral lines.

Study and modelling of the new generation Cd(Zn)Te X and gamma-ray detectors for space applications

International Nuclear Information System (INIS)

Dirks, Bob-Petrus-Franciscus

2006-01-01

The scientific astrophysics community needs a new instrument to gain more insight in the origin of the cosmic X-ray background, the physics of black holes and particle acceleration mechanisms in the energy range between 0.5 to 80 keV. Existing instruments like Chandra and XMM-Newton show very good results up to ∼10 keV but lack sufficient sensitivity above this value. In order to keep or improve the same performances up to ∼80 keV, grazing incidence mirrors with a large focal length of at least 20 m should be used. Since satellites this big cannot be launched with existing launchers, the mirror and detector must be placed on two different satellites flying in formation. The Simbol-X space mission will be the first project of this type. A high sensitivity at 80 keV requires not only a long focal length but also a detection unit with high spatial resolution, using detectors that are still efficient at these relatively high energies. CEA/Saclay/DAPNIA is developing this crucial element for the Simbol-X space mission. The imager consists of several modules, each built from individual X-ray mini-cameras. A single camera is a hybridisation of custom read-out electronics connected to a Cd(Zn)Te semiconductor crystal. The ensemble must be able to efficiently detect photons of up to 80 keV with an energy resolution of ∼1.3 keV (FWHM) at 68 keV. Furthermore it must be equipped with small pixels (∼500*500 μm"2) to attain the desired spatial resolution of 15 arcsec. In order to reach a good sensitivity and energy resolution, ultra-low noise read-out electronics in combination with high-quality semiconductor crystals are mandatory. The read-out electronics, baptised IDeF-X (Imaging Detector Front-end for X-rays), is also developed by CEA/Saclay. A thorough understanding of its functioning as well as its testing forms a part of this work. The spectroscopic performance of the detector is directly related to the electronics noise. The noise characteristics of the ASIC are

Simulation of PEP-II Accelerator Backgrounds Using TURTLE

CERN Document Server

Barlow, Roger J; Kozanecki, Witold; Majewski, Stephanie; Roudeau, Patrick; Stocchi, Achille

2005-01-01

We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using a modified version ofthe DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full programme of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modelling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

The hard x-ray imager onboard IXO

Science.gov (United States)

Nakazawa, Kazuhiro; Takahashi, Tadayuki; Limousin, Olivier; Kokubun, Motohide; Watanabe, Shin; Laurent, Philippe; Arnaud, Monique; Tajima, Hiroyasu

2010-07-01

The Hard X-ray Imager (HXI) is one of the instruments onboard International X-ray Observatory (IXO), to be launched into orbit in 2020s. It covers the energy band of 10-40 keV, providing imaging-spectroscopy with a field of view of 8 x 8 arcmin2. The HXI is attached beneath the Wide Field Imager (WFI) covering 0.1-15 keV. Combined with the super-mirror coating on the mirror assembly, this configuration provides observation of X-ray source in wide energy band (0.1-40.0 keV) simultaneously, which is especially important for varying sources. The HXI sensor part consists of the semiconductor imaging spectrometer, using Si in the medium energy detector and CdTe in the high energy detector as its material, and an active shield covering its back to reduce background in orbit. The HXI technology is based on those of the Japanese-lead new generation X-ray observatory ASTRO-H, and partly from those developed for Simbol-X. Therefore, the technological development is in good progress. In the IXO mission, HXI will provide a major assets to identify the nature of the object by penetrating into thick absorbing materials and determined the inherent spectral shape in the energy band well above the structure around Fe-K lines and edges.

Lowering the background level and the energy threshold of Micromegas x-ray detectors for axion searches

CERN Document Server

Iguaz, F J; Aznar, F; Castel, J F; Dafni, T; Davenport, M; Ferrer-Ribas, E; Galan, J; Garcia, J A; Garza, J G; Giomataris, I; Irastorza, I G; Papaevangelou, T; Rodriguez, A; Tomas, A; Vafeiadis, T; Yildiz, S C

2014-01-01

Axion helioscopes search for solar axions by their conversion in x-rays in the presence of high magnetic fields. The use of low background x-ray detectors is an essential component contributing to the sensitivity of these searches. In this work, we review the recent advances on Micromegas detectors used in the CERN Axion Solar Telescope (CAST) and proposed for the future International Axion Observatory (IAXO). The actual setup in CAST has achieved background levels below 10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$, a factor 100 lower than the first generation of Micromegas detectors. This reduction is based on active and passive shielding techniques, the selection of radiopure materials, offline discrimination techniques and the high granularity of the readout. We describe in detail the background model of the detector, based on its operation at CAST site and at the Canfranc Underground Laboratory (LSC), as well as on Geant4 simulations. The best levels currently achieved at LSC are low than 10$^{-7}$ keV$^{-1}$ ...

Simulation of Beam-Beam Background at CLIC

CERN Document Server

Sailer, Andre

2010-01-01

The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GuineaPig and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam background hitting the vertex detector.

Benchmarking of the simulation of the ATLAS HaLL background

International Nuclear Information System (INIS)

Vincke, H.

2000-01-01

The LHC, mainly to be used as a proton-proton collider, providing collisions at energies of 14 TeV, will be operational in the year 2005. ATLAS, one of the LHC experiments, will provide high accuracy measurements concerning these p-p collisions. In these collisions also a high particle background is produced. This background was already calculated with the Monte Carlo simulation program FLUKA. Unfortunately, the prediction concerning this background rate is only understood within an uncertainty level of five. The main contribution of this factor can be seen as limited knowledge concerning the ability of FLUKA to simulate these kinds of scenarios. In order to reduce the uncertainty, benchmarking simulations of experiments similar to the ATLAS background situation were performed. The comparison of the simulations with the experiments proves to which extent FLUKA is able to provide reliable results concerning the ATLAS background situation. In order to perform this benchmark, an iron construction was irradiated by a hadron beam. The primary particles had ATLAS equivalent energies. Behind the iron structure, the remnants of the shower processes are measured and simulated. The simulation procedure and its encouraging results, including the comparison with the measured numbers, are presented and discussed in this work. (author)

Background simulation for the GENIUS project

International Nuclear Information System (INIS)

Ponkratenko, O.A.; Tretyak, V.I.; Zdesenko, Yu.G.

1999-01-01

The background simulations for the GENIUS experiment were performed with the help of GEANT 3.21 package and event generator DECAY 4.Contributions from the cosmogenic activity produced in the Ge detectors and from its radioactive impurities as well as from contamination of the liquid nitrogen and other materials were calculated.External gamma and neutron background were taking into consideration also.The results of calculations evidently show feasibility of the GENIUS project,which can substantially promote development of modern astroparticle physics

Monte Carlo simulations of low background detectors

International Nuclear Information System (INIS)

Miley, H.S.; Brodzinski, R.L.; Hensley, W.K.; Reeves, J.H.

1995-01-01

An implementation of the Electron Gamma Shower 4 code (EGS4) has been developed to allow convenient simulation of typical gamma ray measurement systems. Coincidence gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra for the purpose of extremely low-level assay. Monte Carlo calculations of this sort can be extremely successful since low background detectors are usually free of significant contributions from poorly localized radiation sources, such as cosmic muons, secondary cosmic neutrons, and radioactive construction or shielding materials. Previously, validation of this code has been obtained from a series of comparisons between measurements and blind calculations. An example of the application of this code to an exceedingly low background spectrum stripping will be presented. (author) 5 refs.; 3 figs.; 1 tab

Upaya Peningkatan Kemampuan Membaca Melalui Media Gambar Simbol Untuk Anak Tunagrahita Sedang

Directory of Open Access Journals (Sweden)

Erni Yulis

2016-12-01

Full Text Available Penelitian ini dimulai dari kesulitan siswa tunagrahita untuk membaca. Mereka mempunyai ciri yang khusus.Salah satu ciri khususnya adalah kemampuan intelegensi mereka di bawah rata.Siswa yang seperti ini membutuhkan pengelolaan kelas yang lebih intensif.Sehingga mereka dapat memahami materi pelajaran untuk dapat hidup secara mandiri.Rumusan masalah dalam penelitian ini adalah upaya dalam meningkatkan kemampuan membaca siswa melalui media gambar simbol bagi anak tunagrahita sedang pada kelas DIII/C1 di SLB YPPLB Padang.Penelitian ini menggunakan prosedur penelitian tindakan kelas.Penelitian ini dilaksanakan sebanyak 2 siklus.Setiap siklus melaksanakan pembelajaran sebanyak lima kali. Hasil penelitian menunjukkan bahwa media gambar symbol dapat meningkatkan kemampuan membaca siswa tungrahita.

Manual for the Jet Event and Background Simulation Library

Energy Technology Data Exchange (ETDEWEB)

Heinz, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Angerami, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-11

Jets are the collimated streams of particles resulting from hard scattering in the initial state of high-energy collisions. In heavy-ion collisions, jets interact with the quark-gluon plasma (QGP) before freezeout, providing a probe into the internal structure and properties of the QGP. In order to study jets, background must be subtracted from the measured event, potentially introducing a bias. We aim to understand and quantify this subtraction bias. PYTHIA, a library to simulate pure jet events, is used to simulate a model for a signature with one pure jet (a photon) and one quenched jet, where all quenched particle momenta are reduced by a user-de ned constant fraction. Background for the event is simulated using multiplicity values generated by the TRENTO initial state model of heavy-ion collisions fed into a thermal model consisting of a 3-dimensional Boltzmann distribution for particle types and momenta. Data from the simulated events is used to train a statistical model, which computes a posterior distribution of the quench factor for a data set. The model was tested rst on pure jet events and then on full events including the background. This model will allow for a quantitative determination of biases induced by various methods of background subtraction.

Envelope method for background elimination from X-ray fluorescence spectra

International Nuclear Information System (INIS)

Monakhov, V.V.; Naumenko, P.A.; Chashinskaya, O.A.

2006-01-01

The influence of the background noise caused by Bremsstrahlung on the accuracy of the envelope method at x-ray fluorescence spectra processing is studied. This is carried out by the example of model spectra at different forms of Bremsstrahlung noise as well as at the presence of background noise in spectra. The interpolation by parabolic splines is used for the estimation of the error of the envelope method for the elimination of continuos background noise. It is found out that the error of the proposed method constitutes decimal parts of percent. It is shown that the envelope method is the effective technique for the elimination of the continuous Bremsstrahlung from x-ray fluorescence spectra of the first order [ru

Monte Carlo simulations for the optimisation of low-background Ge detector designs

Energy Technology Data Exchange (ETDEWEB)

Hakenmueller, Janina; Heusser, Gerd; Maneschg, Werner; Schreiner, Jochen; Simgen, Hardy; Stolzenburg, Dominik; Strecker, Herbert; Weber, Marc; Westernmann, Jonas [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Laubenstein, Matthias [Laboratori Nazionali del Gran Sasso, Via G. Acitelli 22, 67100 Assergi L' Aquila (Italy)

2015-07-01

Monte Carlo simulations for the low-background Ge spectrometer Giove at the underground laboratory of MPI-K, Heidelberg, are presented. In order to reduce the cosmogenic background at the present shallow depth (15 m w.e.) the shielding of the spectrometer includes an active muon veto and a passive shielding (lead and borated PE layers). The achieved background suppression is comparable to Ge spectrometers operated in much greater depth. The geometry of the detector and the shielding were implemented using the Geant4-based toolkit MaGe. The simulations were successfully optimised by determining the correct diode position and active volume. With the help of the validated Monte Carlo simulation the contribution of the single components to the overall background can be examined. This includes a comparison between simulated results and measurements with different fillings of the sample chamber. Having reproduced the measured detector background in the simulation provides the possibility to improve the background by reverse engineering of the passive and active shield layers in the simulation.

Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries

Science.gov (United States)

Madau, Piero; Fragos, Tassos

2017-05-01

We compute the expected X-ray diffuse background and radiative feedback on the intergalactic medium (IGM) from X-ray binaries prior to and during the epoch of reionization. The cosmic evolution of compact binaries is followed using a population synthesis technique that treats separately neutron stars and black hole binaries in different spectral states and is calibrated to reproduce the observed X-ray properties of galaxies at z ≲ 4. Together with an updated empirical determination of the cosmic history of star formation, recent modeling of the stellar mass-metallicity relation, and a scheme for absorption by the IGM that accounts for the presence of ionized H II bubbles during the epoch of reionization, our detailed calculations provide refined predictions of the X-ray volume emissivity and filtered radiation background from “normal” galaxies at z ≳ 6. Radiative transfer effects modulate the background spectrum, which shows a characteristic peak between 1 and 2 keV. Because of the energy dependence of photoabsorption, soft X-ray photons are produced by local sources, while more energetic radiation arrives unattenuated from larger cosmological volumes. While the filtering of X-ray radiation through the IGM slightly increases the mean excess energy per photoionization, it also weakens the radiation intensity below 1 keV, lowering the mean photoionization and heating rates. Numerical integration of the rate and energy equations shows that the contribution of X-ray binaries to the ionization of the bulk IGM is negligible, with the electron fraction never exceeding 1%. Direct He I photoionizations are the main source of IGM heating, and the temperature of the largely neutral medium in between H II cavities increases above the temperature of the cosmic microwave background (CMB) only at z ≲ 10, when the volume filling factor of H II bubbles is already ≳0.1. Therefore, in this scenario, it is only at relatively late epochs that neutral intergalactic hydrogen

Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries

Energy Technology Data Exchange (ETDEWEB)

Madau, Piero [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Fragos, Tassos [Geneva Observatory, University of Geneva, Chemin des Maillettes 51, 1290 Sauverny (Switzerland)

2017-05-01

We compute the expected X-ray diffuse background and radiative feedback on the intergalactic medium (IGM) from X-ray binaries prior to and during the epoch of reionization. The cosmic evolution of compact binaries is followed using a population synthesis technique that treats separately neutron stars and black hole binaries in different spectral states and is calibrated to reproduce the observed X-ray properties of galaxies at z ≲ 4. Together with an updated empirical determination of the cosmic history of star formation, recent modeling of the stellar mass–metallicity relation, and a scheme for absorption by the IGM that accounts for the presence of ionized H ii bubbles during the epoch of reionization, our detailed calculations provide refined predictions of the X-ray volume emissivity and filtered radiation background from “normal” galaxies at z ≳ 6. Radiative transfer effects modulate the background spectrum, which shows a characteristic peak between 1 and 2 keV. Because of the energy dependence of photoabsorption, soft X-ray photons are produced by local sources, while more energetic radiation arrives unattenuated from larger cosmological volumes. While the filtering of X-ray radiation through the IGM slightly increases the mean excess energy per photoionization, it also weakens the radiation intensity below 1 keV, lowering the mean photoionization and heating rates. Numerical integration of the rate and energy equations shows that the contribution of X-ray binaries to the ionization of the bulk IGM is negligible, with the electron fraction never exceeding 1%. Direct He i photoionizations are the main source of IGM heating, and the temperature of the largely neutral medium in between H ii cavities increases above the temperature of the cosmic microwave background (CMB) only at z ≲ 10, when the volume filling factor of H ii bubbles is already ≳0.1. Therefore, in this scenario, it is only at relatively late epochs that neutral intergalactic

MASJID JAMI PITI LAKSAMANA MUHAMMAD CHENG HO PURBALINGGA: SIMBOL KEINDAHAN TOLERANSI DALAM AKULTURASI

Directory of Open Access Journals (Sweden)

Dinda Wulan Afriani

2015-10-01

terletak di Kabupaten Purbalingga, Jawa Tengah. Masjid Laksamana Muhammad Cheng Ho Purbalingga merupakan salah satu dari tiga masjid Cheng Ho di Indonesia. Kehadiran masjid ini merupakan wujud simbol keindahan toleransi antar etnis dan budaya dalam sebuah akulturasi. Bentuk arsitektur masjid ini merupakan perpaduan dari budaya Islam- Tiongkok-Arab-Jawa. Keistimewaan masjid ini bukan hanya terletak pada bentuk arsitektur bangunan dan ragam hias arsitekturnya saja. Namun juga pada keindahan makna dan nilai falsafah kehidupan yang terkandung di dalamnya, yang tentu saja selaras dengan peran sertanya dalam masyarakat. Dalam membaca tanda dan makna, artikel ini juga menyajikan penalaran melalui metode semiotika visual secara singkat namun cukup padat.

Numerical method for IR background and clutter simulation

Science.gov (United States)

Quaranta, Carlo; Daniele, Gina; Balzarotti, Giorgio

1997-06-01

The paper describes a fast and accurate algorithm of IR background noise and clutter generation for application in scene simulations. The process is based on the hypothesis that background might be modeled as a statistical process where amplitude of signal obeys to the Gaussian distribution rule and zones of the same scene meet a correlation function with exponential form. The algorithm allows to provide an accurate mathematical approximation of the model and also an excellent fidelity with reality, that appears from a comparison with images from IR sensors. The proposed method shows advantages with respect to methods based on the filtering of white noise in time or frequency domain as it requires a limited number of computation and, furthermore, it is more accurate than the quasi random processes. The background generation starts from a reticule of few points and by means of growing rules the process is extended to the whole scene of required dimension and resolution. The statistical property of the model are properly maintained in the simulation process. The paper gives specific attention to the mathematical aspects of the algorithm and provides a number of simulations and comparisons with real scenes.

Background approximation in automatic qualitative X-ray-fluorescent analysis

International Nuclear Information System (INIS)

Jordanov, J.; Tsanov, T.; Stefanov, R.; Jordanov, N.; Paunov, M.

1982-01-01

An empirical method of finding the dependence of the background intensity (Isub(bg) on the wavelength is proposed, based on the approximation of the experimentally found values for the background in the course of an automatic qualitative X-ray fluorescent analysis with pre-set curve. It is assumed that the dependence I(lambda) will be well approximated by a curve of the type Isub(bg)=(lambda-lambda sub(o)sup(fsub(1)(lambda))exp[fsub(2)(lambda)] where fsub(1) (lambda) and f 2 (lambda) are linear functions with respect to the sought parameters. This assumption was checked out on a ''pure'' starch background, in which it is not known beforehand which points belong to the background. It was assumed that the dependence I(lambda) can be found from all minima in the spectrum. Three types of minima has been distinguished: 1. the lowest point between two well-solved X-ray lines; 2. a minimum obtained as a result of statistical fluctuations of the measured signal; 3. the lowest point between two overlapped lines. The minima strongly deviating from the background are removed from the obtained set. The sum-total of the remaining minima serves as a base for the approximation of the dependence I(lambda). The unknown parameters are determined by means of the LSM. The approximated curve obtained by this method is closer to the real background than the background determined by the method described by Kigaki Denki, as the effect of all recorded minima is taken into account. As an example the PbTe spectrum recorded with crystal LiF 220 is shown graphically. The curve well describes the background of the spectrum even in the regions in which there are no minima belonging to the background. (authors)

Full simulation of the beam-related backgrounds at the ILC

Energy Technology Data Exchange (ETDEWEB)

Schuetz, Anne [DESY (Germany); KIT (Germany)

2016-07-01

The ILC has been proposed as the next machine at the energy frontier and a Technical Design Report was presented in 2012. As part of the site-specific studies to prepare the hosting of the ILC in Japan, the final focus region of the ILC had to be adapted. In this contribution, updated results for the beam-related background as well as new results for the backgrounds originating from the beam dump are presented. The beam-related backgrounds are simulated using GuineaPig and are then propagated through the full simulation of the SiD detector. The impact of various modifications in the final-focus region on the detector occupancies are then evaluated. For the neutron background from the beam dump, the FLUKA simulation suite is used, which is well established for dosimetry and shielding studies. With this program, the effect of the neutrons from the ILC beam dumps on the ILC detectors are studied.

A novel natural environment background model for Monte Carlo simulation and its application in the simulation of anticoincidence measurement

International Nuclear Information System (INIS)

Li, Sangang; Wang, Lei; Cheng, Yi; Tuo, Xianguo; Liu, Mingzhe; Yao, Fuliang; Leng, Fengqing; Cheng, Yuanyuan; Cai, Ting; Zhou, Yan

2016-01-01

This study proposes a novel natural environment background model by modeling brief environment conditions. It uses Geant4 program to simulate decays of "2"3"8U, "2"3"2Th, and "4"0K in soil and obtains compositions of different-energy gamma rays in the natural environment background. The simulated gamma spectrum of the natural environment background agrees well with the experimental spectrum, particularly above 250 keV. The model is used in the simulation of anticoincidence measurement, indicating that the natural environment background can be decreased by approximately 88%, and the Compton attenuation factor is 2.22. The simulation of anticoincidence measurement can improve the minimum detectable activity (MDA) of the detection system. - Highlights: • This study proposes a novel natural environment background model by simulating decays of "2"3"8U, "2"3"2Th, and "4"0K in soil. • The simulated gamma spectrum of the natural environment background agrees well with the experimental spectrum, particularly above 250 keV. • The proposed environment background model is applied to study the properties of anticoincidence detector.

SIMBOL BUDAYA SEBAGAI REPRESENTASI POSITIONING DALAM IKLAN PRODUK MOBIL EROPA DAN MOBIL JEPANG

Directory of Open Access Journals (Sweden)

Andrian Dektisa Hagijanto

2003-01-01

Full Text Available Understanding advertising is not as simple and short as looking at it. Besides it is used as visual approach to create persuasif communication%2C advetisement can be created with something pointed to reality and hyperreality. Complexity can be more felt whenever cultural symbol is used as aplication in positioning approach. Abstract in Bahasa Indonesia : Memahami iklan tidak sesederhana dan sesingkat menikmati iklan tersebut. Selain dipakai sebagai pendekatan visual untuk menciptakan komunikasi persuasif%2C iklan dapat dikreasi dengan citraan yang mengacu kepada realitas dan bahasa realitas semu (hiper-realitas. Kompleksitas ini makin terasa lagi ketika simbol budaya yang dipakai sebagai pendekatan aplikasi posisioning. Positioning representation%2C cultural symbol%2C car advertisement.

Resolving the Origin of the Diffuse Soft X-ray Background

Science.gov (United States)

Smith, Randall K.; Foster, Adam R.; Edgar, Ricard J.; Brickhouse, Nancy S.; Sanders, Wilton T.

2012-01-01

In January 1993, the Diffuse X-ray Spectrometer (DXS) measured the first high-resolution spectrum of the diffuse soft X-ray background between 44-80A. A line-dominated spectrum characteristic of a 10(exp 6)K collisionally ionized plasma' was expected but while the observed spectrum was clearly line-dominated, no model would fit. Then in 2003 the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) launched and observed the diffuse extreme-ultraviolet (EUV) spectrum between 90- 265A. Although many emission lines were again expected; only Fe IX at 171.1A was detected. The discovery of X-rays from comets led to the realization that heavy ions (Z=6-28) in the solar wind will emit soft X-rays as the ions interact via charge exchange with neutral atoms in the heliosphere and geocorona. Using a new model for solar wind charge exchange (SWCX) emission, we show that the diffuse soft X-ray background can be understood as a combination of emission from charge exchange onto the slow and fast solar wind together with a more distant and diffuse hot (10(exp 6)K) plasma.

Optimization of a fluorescence X-ray source and background studies for a prospective CNNS experiment

Energy Technology Data Exchange (ETDEWEB)

Zoeller, Andreas; Ciemniak, Christian; Feilitzsch, Franz von; Guetlein, Achim; Haag, Nils; Hofmann, Martin; Isaila, Christian; Lanfranchi, Jean-Come; Oberauer, Lothar; Pfister, Sebastian; Potzel, Walter; Roth, Sabine; Schoenert, Stefan; Sivers, Moritz von; Strauss, Raimund [Technische Universitaet Muenchen, Physik-Department, E15 (Germany); Lachenmaier, Tobias [Eberhard Karls Universitaet, Tuebingen (Germany)

2011-07-01

Coherent Neutrino Nucleus Scattering (CNNS) is predicted by the Standard Model but hasn't been measured yet. A good background discrimination and shielding is essential for the achievement of a prospective experiment. We show the results of simulations for background discrimination and suppression using a myon veto system in combination with a shielding around a cryostat. With CNNS, the expected nuclear recoil energy for reactor anti-neutrinos is in the range of x-ray source with nine clearly separated energy lines between {proportional_to}1 keV and 6.5 keV are shown.

Young Stellar Objects from Soft to Hard X-rays

Science.gov (United States)

Güdel, Manuel

2009-05-01

Magnetically active stars are the sites of efficient particle acceleration and plasma heating, processes that have been studied in detail in the solar corona. Investigation of such processes in young stellar objects is much more challenging due to various absorption processes. There is, however, evidence for violent magnetic energy release in very young stellar objects. The impact on young stellar environments (e.g., circumstellar disk heating and ionization, operation of chemical networks, photoevaporation) may be substantial. Hard X-ray devices like those carried on Simbol-X will establish a basis for detailed studies of these processes.

Optimization of detectors positioning with respect to flying dynamics for future formation flight missions

Science.gov (United States)

Civitani, Marta; Djalal, Sophie; Chipaux, Remi

2009-08-01

In a X-ray telescope in formation flight configuration, the optics and the focal-plane detectors reside in two different spacecraft. The dynamics of the detector spacecraft (DSC) with respect to the mirror spacecraft (MSC, carrying the mirrors of the telescope) changes continuously the arrival positions of the photons on the detectors. In this paper we analyze this issue for the case of the SIMBOL-X hard X-ray mission, extensively studied by CNES and ASI until 2009 spring. Due to the existing gaps between pixels and between detector modules, the dynamics of the system may produce a relevant photometric effect. The aim of this work is to present the optimization study of the control-law algorithm with respect to the detector's geometry. As the photometric effect may vary depending upon position of the source image on the detector, the analysis-carried out using the simuLOS (INAF, CNES, CEA) simulation tool-is extended over the entire SIMBOL-X field of view.

A novel natural environment background model for Monte Carlo simulation and its application in the simulation of anticoincidence measurement.

Science.gov (United States)

Li, Sangang; Wang, Lei; Cheng, Yi; Tuo, Xianguo; Liu, Mingzhe; Yao, Fuliang; Leng, Fengqing; Cheng, Yuanyuan; Cai, Ting; Zhou, Yan

2016-02-01

This study proposes a novel natural environment background model by modeling brief environment conditions. It uses Geant4 program to simulate decays of (238)U, (232)Th, and (40)K in soil and obtains compositions of different-energy gamma rays in the natural environment background. The simulated gamma spectrum of the natural environment background agrees well with the experimental spectrum, particularly above 250 keV. The model is used in the simulation of anticoincidence measurement, indicating that the natural environment background can be decreased by approximately 88%, and the Compton attenuation factor is 2.22. The simulation of anticoincidence measurement can improve the minimum detectable activity (MDA) of the detection system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simulation of Beam-Beam Background at CLIC

CERN Document Server

Sailer, A

2010-01-01

The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GUINEAPIG and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam back- ground hitting the vertex detector.

Cosmic X-ray background from hot gas

International Nuclear Information System (INIS)

Rogers, R.D.; Field, G.B.

1991-01-01

This paper considers constraints on models of the cosmic X-ray background (XRB) in which the XRB is produced by optically thin thermal bremsstrahlung from hot gas. It is shown that models in which the gas is gravitationally confined in a spherical configuration and is heated only once are contradicted by the observed number of gravitationally lensed quasars together with the lower limit on the number of XRB sources required by limits on fluctuations in the XRB and the cosmic microwave background. In addition, it is shown that, for models in which the gas is not gravitationally confined, the expansion time of the gas is much shorter than the radiative cooling time, so that such models cannot explain the XRB. It is concluded that thermal bremsstrahlung models cannot account for the XRB if the emitting gas is heated only once. 31 refs

Contributions of late-type dwarf stars to the soft X-ray diffuse background

Energy Technology Data Exchange (ETDEWEB)

Schmitt, J.H.M.M.; Snowden, S.L. (Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany, F.R.) Wisconsin Univ., Madison (USA))

1990-09-01

Comprehensive calculations of the contribution of late-type dwarf stars to the soft X-ray diffuse background are presented. The mean X-ray luminosity as derived from optically and X-ray selected samples is examined, using the Bahcall-Soneira Galaxy model to describe the spatial distribution of stars and recent results on the X-ray spectra. The model calculations are compared with the Wisconsin sky maps in the C, M1, M2, I and J bands to assess the uncertainties of the calculations. Contributions of up to 10 percent to the M2 and I band background at high Galactic latitudes are found, while at low Galactic latitudes late-type stars contribute up to 40 percent of the background. However, a Galactic ridge as well as a relatively isotropic component still remains unexplained, even with the added contribution of the extrapolated high-energy power law. 41 refs.

Contributions of late-type dwarf stars to the soft X-ray diffuse background

Science.gov (United States)

Schmitt, J. H. M. M.; Snowden, S. L.

1990-01-01

Comprehensive calculations of the contribution of late-type dwarf stars to the soft X-ray diffuse background are presented. The mean X-ray luminosity as derived from optically and X-ray selected samples is examined, using the Bahcall-Soneira Galaxy model to describe the spatial distribution of stars and recent results on the X-ray spectra. The model calculations are compared with the Wisconsin sky maps in the C, M1, M2, I and J bands to assess the uncertainties of the calculations. Contributions of up to 10 percent to the M2 and I band background at high Galactic latitudes are found, while at low Galactic latitudes late-type stars contribute up to 40 percent of the background. However, a Galactic ridge as well as a relatively isotropic component still remains unexplained, even with the added contribution of the extrapolated high-energy power law.

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.

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.

The LOFT (Large Observatory for X-ray Timing) background simulations

DEFF Research Database (Denmark)

Campana, R.; Feroci, M.; Del Monte, E.

2012-01-01

The Large Observatory For X-ray Timing (LOFT) is an innovative medium-class mission selected for an assessment phase in the framework of the ESA M3 Cosmic Vision call. LOFT is intended to answer fundamental questions about the behavior of matter in theh very strong gravitational and magnetic fields...

Manual for the Jet Event and Background Simulation Library(JEBSimLib)

Energy Technology Data Exchange (ETDEWEB)

Heinz, Matthias [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, Ron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Angerami, Aaron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-08-29

Jets are the collimated streams of particles resulting from hard scattering in the initial state of high-energy collisions. In heavy-ion collisions, jets interact with the quark-gluon plasma (QGP) before freezeout, providing a probe into the internal structure and properties of the QGP. In order to study jets, background must be subtracted from the measured event, potentially introducing a bias. We aim to understand and quantify this subtraction bias. PYTHIA, a library to simulate pure jet events, is used to simulate a model for a signature with one pure jet (a photon) and one quenched jet, where all quenched particle momenta are reduced by a user-de ned constant fraction. Background for the event is simulated using multiplicity values generated by the TRENTO initial state model of heavy-ion collisions fed into a thermal model consisting of a 3-dimensional Boltzmann distribution for particle types and momenta. Data from the simulated events is used to train a statistical model, which computes a posterior distribution of the quench factor for a data set. The model was tested rst on pure jet events and then on full events including the background. This model will allow for a quantitative determination of biases induced by various methods of background subtraction.

MDT Performance in a High Rate Background Environment

CERN Document Server

Aleksa, Martin; Hessey, N P; Riegler, W

1998-01-01

A Cs137 gamma source with different lead filters in the SPS beam-line X5 has been used to simulate the ATLAS background radiation. This note shows the impact of high background rates on the MDT efficiency and resolution for three kinds of pulse shaping and compares the results with GARFIELD simulations. Furthermore it explains how the performance can be improved by time slewing corrections and double track separation.

Light from electron avalanches and background rejection in X-ray astronomy

International Nuclear Information System (INIS)

Siegmund, O.H.W.; Sanford, P.W.; Mason, I.M.; Culhane, J.L.; Cockshott, R.

1980-01-01

A modified version of the parallel plate imaging proportional counter, developed to register images of cosmic x-ray sources in the focal planes of x-ray telescopes, has been constructed to investigate the application of risetime discrimination to the scintillation pulses caused by the electron avalanche process. It is shown that efficient background event rejection (> 90%) is achieved and the application of this system for x-ray astronomy is discussed. (U.K.)

The Ultraluminous X-Ray Source X-37 Is a Background Quasar in the Antennae Galaxies

Science.gov (United States)

Clark, D. M.; Christopher, M. H.; Eikenberry, S. S.; Brandl, B. R.; Wilson, J. C.; Carson, J. C.; Henderson, C. P.; Hayward, T. L.; Barry, D. J.; Ptak, A. F.; Colbert, E. J. M.

2005-10-01

In this Letter we report that a bright, X-ray source in the Antennae galaxies (NGC 4038/9), previously identified as an ultraluminous X-ray source (ULX), is in fact a background quasar. We identify an isolated infrared and optical counterpart within 0.3" +/- 0.5" of the X-ray source X-37. After acquiring an optical spectrum of its counterpart, we use the narrow [O III] and broad Hα emission lines to identify X-37 as a quasar at a redshift of z=0.26. Through a U, V, and Ks photometric analysis, we demonstrate that most of the observable light along this line of sight is from the quasar. We discuss the implications of this discovery and the importance of acquiring spectra for optical and IR counterparts to ULXs.

A New Measurement of the Cosmic X-ray Background

International Nuclear Information System (INIS)

Moretti, A.

2009-01-01

I present a new analytical description of the cosmic X-ray background (CXRB) spectrum in the 1.5-200 keV energy band, obtained by combining the new measurement performed by the Swift X-ray telescope (XRT) with the recently published Swift burst alert telescope (BAT) measurement. A study of the cosmic variance in the XRT band (1.5-7 keV) is also presented. I find that the expected cosmic variance (expected from LogN-LogS) scales as Ω -0.3 (where Ω is the surveyed area) in very good agreement with XRT data.

Simulation of multiple scattering background in heavy ion backscattering spectrometry

International Nuclear Information System (INIS)

Li, M.M.; O'Connor, D.J.

1999-01-01

With the development of heavy ion backscattering spectrometry (HIBS) for the detection of trace quantities of heavy-atom impurities on Si surfaces, it is necessary to quantify the multiple scattering contribution to the spectral background. In the present work, the Monte Carlo computer simulation program TRIM has been used to study the backscattering spectrum and the multiple scattering background features for heavy ions C, Ne, Si, Ar and Kr impinging on four types of targets: (1) a single ultra-thin (free standing) Au film of 10 A thickness, (2) a 10 A Au film on a 50 A Si surface, (3) a 10 A Au film on an Si substrate (10 000 A), and (4) a thick target (10 000 A) of pure Si. The ratio of the signal from the Au thin layer to the background due to multiple scattering has been derived by fitting the simulation results. From the simulation results, it is found that the Au film contributes to the background which the Si plays a role in developing due to the ion's multiple scattering in the substrate. Such a background is generated neither by only the Au thin layer nor by the pure Si substrate independently. The corresponding mechanism of multiple scattering in the target can be explained as one large-angle scattering in the Au layer and subsequently several small angle scatterings in the substrate. This study allows an appropriate choice of incident beam species and energy range when the HIBS is utilized to analyse low level impurities in Si wafers

Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

Energy Technology Data Exchange (ETDEWEB)

Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Madejski, Grzegorz M. [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Rikkyo Univ., Tokyo (Japan). Dept. of Physics

2013-09-24

While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10^-12 erg/cm²/s^-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

Probing the cosmic x-ray and MeV gamma ray background radiation through the anisotropy

Energy Technology Data Exchange (ETDEWEB)

Inoue, Yoshiyuki [Stanford Univ., CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States); Madejski, Grzegorz M. [Stanford Univ., CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States); Rikkyo Univ., Tokyo (Japan)

2013-09-24

While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once future hard X-ray all sky satellites achieve a sensitivity better than 10–12 erg cm–2 s–1 at 10-30 keV or 30-50 keV—although this is beyond the sensitivities of current hard X-ray all sky monitors—angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

Simulation of backgrounds in detectors and energy deposition in superconducting magnets at μ+μ- colliders

International Nuclear Information System (INIS)

Mokhov, N.V.; Striganov, S.I.

1996-01-01

A calculational approach is described to study beam induced radiation effects in detector and storage ring components at high-energy high-luminosity μ + μ - colliders. The details of the corresponding physics process simulations used in the MARS code are given. Contributions of electromagnetic showers, synchrotron radiation, hadrons and daughter muons to the background rates in a generic detector for a 2 x 2 TeV μ + μ - collider are investigated. Four configurations of the inner triplet and a detector are examined for two sources: muon decays and beam halo interactions in the lattice elements. The beam induced power density in superconducting magnets is calculated and ways to reduce it are proposed

CXBN: a blueprint for an improved measurement of the cosmological x-ray background

Science.gov (United States)

Simms, Lance M.; Jernigan, J. G.; Malphrus, Benjamin K.; McNeil, Roger; Brown, Kevin Z.; Rose, Tyler G.; Lim, Hyoung S.; Anderson, Steven; Kruth, Jeffrey A.; Doty, John P.; Wampler-Doty, Matthew; Cominsky, Lynn R.; Prasad, Kamal S.; Thomas, Eric T.; Combs, Michael S.; Kroll, Robert T.; Cahall, Benjamin J.; Turba, Tyler T.; Molton, Brandon L.; Powell, Margaret M.; Fitzpatrick, Jonathan F.; Graves, Daniel C.; Gaalema, Stephen D.; Sun, Shunming

2012-10-01

A precise measurement of the Cosmic X-ray Background (CXB) is crucial for constraining models of the evolution and composition of the universe. While several large, expensive satellites have measured the CXB as a secondary mission, there is still disagreement about normalization of its spectrum. The Cosmic X-ray Background NanoSat (CXBN) is a small, low-cost satellite whose primary goal is to measure the CXB over its two-year lifetime. Benefiting from a low instrument-induced background due to its small mass and size, CXBN will use a novel, pixelated Cadmium Zinc Telluride (CZT) detector with energy resolution strategy for scanning the sky and calibrating the data, and presents the expected results over the two-year mission lifetime.

On the contribution of active galactic nuclei to the diffuse X-ray background

International Nuclear Information System (INIS)

Avni, Y.

1977-01-01

It is shown that cosmological evolution has a pronounced effect on the contributions of active galactic nuclei to the diffuse x-ray background. The dependence of such contributions on the form and amount of density evolution, on the deceleration parameter, and on the formation epoch is found. It is established, in particular, that x-ray Seyferts can account for all of the observed 2-10 keV background when the effects of evolution are considered; the required amount of evolution is intermediate between the evolution of quasars and no evolution. (author)

On the contribution of active galactic nuclei to the diffuse X-ray background

International Nuclear Information System (INIS)

Avni, Y.

1978-01-01

We show that cosmological evolution has a pronounced effect on the contributions of active galactic nuclei to the diffuse x-ray background. We find the dependence of such contributions on the form and amount of density evolution, on the deceleration parameter, and on the formation epoch. We find in particular that x-ray Seyferts can account for all of the observed 2-10 keV background when the effects of evolution are considered; the required amount of evolution is intermediate between the evolution of quasars and no evolution. (orig.) [de

CdTe Based Hard X-ray Imager Technology For Space Borne Missions

Science.gov (United States)

Limousin, Olivier; Delagnes, E.; Laurent, P.; Lugiez, F.; Gevin, O.; Meuris, A.

2009-01-01

CEA Saclay has recently developed an innovative technology for CdTe based Pixelated Hard X-Ray Imagers with high spectral performance and high timing resolution for efficient background rejection when the camera is coupled to an active veto shield. This development has been done in a R&D program supported by CNES (French National Space Agency) and has been optimized towards the Simbol-X mission requirements. In the latter telescope, the hard X-Ray imager is 64 cm² and is equipped with 625µm pitch pixels (16384 independent channels) operating at -40°C in the range of 4 to 80 keV. The camera we demonstrate in this paper consists of a mosaic of 64 independent cameras, divided in 8 independent sectors. Each elementary detection unit, called Caliste, is the hybridization of a 256-pixel Cadmium Telluride (CdTe) detector with full custom front-end electronics into a unique 1 cm² component, juxtaposable on its four sides. Recently, promising results have been obtained from the first micro-camera prototypes called Caliste 64 and will be presented to illustrate the capabilities of the device as well as the expected performance of an instrument based on it. The modular design of Caliste enables to consider extended developments toward IXO type mission, according to its specific scientific requirements.

CROSS-CORRELATION BETWEEN X-RAY AND OPTICAL/NEAR-INFRARED BACKGROUND INTENSITY FLUCTUATIONS

Energy Technology Data Exchange (ETDEWEB)

Mitchell-Wynne, Ketron; Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Xue, Yongquan [CAS Key Laboratory for Researches in Galaxies and Cosmology, Center for Astrophysics, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Luo, Bin [School of Astronomy and Space Science, Nanjing University, Nanjing, 210093 (China); Brandt, William [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA, 16802 (United States); Koekemoer, Anton [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2016-12-01

Angular power spectra of optical and infrared background anisotropies at wavelengths between 0.5 and 5 μ m are a useful probe of faint sources present during reionization, in addition to faint galaxies and diffuse signals at low redshift. The cross-correlation of these fluctuations with backgrounds at other wavelengths can be used to separate some of these signals. A previous study on the cross-correlation between X-ray and Spitzer fluctuations at 3.6 μ m and 4.5 μ m has been interpreted as evidence for direct collapse black holes present at z  > 12. Here we return to this cross-correlation and study its wavelength dependence from 0.5 to 4.5 μ m using Hubble and Spitzer data in combination with a subset of the 4 Ms Chandra observations in GOODS-S/ECDFS. Our study involves five Hubble bands at 0.6, 0.7, 0.85, 1.25, and 1.6 μ m, and two Spitzer -IRAC bands at 3.6 μ m and 4.5 μ m. We confirm the previously seen cross-correlation between 3.6 μ m (4.5 μ m) and X-rays with 3.7 σ (4.2 σ ) and 2.7 σ (3.7 σ ) detections in the soft [0.5–2] keV and hard [2–8] keV X-ray bands, respectively, at angular scales above 20 arcsec. The cross-correlation of X-rays with Hubble is largely anticorrelated, ranging between the levels of 1.4 σ –3.5 σ for all the Hubble and X-ray bands. This lack of correlation in the shorter optical/NIR bands implies the sources responsible for the cosmic infrared background at 3.6 and 4.5 μ m are at least partly dissimilar to those at 1.6 μ m and shorter.

Multiple x-ray diffraction simulation and applications

International Nuclear Information System (INIS)

Costa, C.A.B.S. da.

1989-09-01

A computer program (MULTX) was implemented for simulation X-ray multiple diffraction diagrams in Renninger geometries. The program uses the X-ray multiple diffraction theory for imperfect crystals. The iterative calculation of the intensities is based on the Taylor series general term, and the primary beam power expansion is given as function of the beam x penetration in the crystal surface. This development allows to consider the simultaneous interaction of the beams involved in the multiple diffraction phenomenon. The simulated diagrams are calculated point-to-point and the tests for the Si and GaAs presented good reproduction of the experimental diagrams for different primary reflections. (L.C.J.A.)

X-CSIT: a toolkit for simulating 2D pixel detectors

Science.gov (United States)

Joy, A.; Wing, M.; Hauf, S.; Kuster, M.; Rüter, T.

2015-04-01

A new, modular toolkit for creating simulations of 2D X-ray pixel detectors, X-CSIT (X-ray Camera SImulation Toolkit), is being developed. The toolkit uses three sequential simulations of detector processes which model photon interactions, electron charge cloud spreading with a high charge density plasma model and common electronic components used in detector readout. In addition, because of the wide variety in pixel detector design, X-CSIT has been designed as a modular platform so that existing functions can be modified or additional functionality added if the specific design of a detector demands it. X-CSIT will be used to create simulations of the detectors at the European XFEL, including three bespoke 2D detectors: the Adaptive Gain Integrating Pixel Detector (AGIPD), Large Pixel Detector (LPD) and DePFET Sensor with Signal Compression (DSSC). These simulations will be used by the detector group at the European XFEL for detector characterisation and calibration. For this purpose, X-CSIT has been integrated into the European XFEL's software framework, Karabo. This will further make it available to users to aid with the planning of experiments and analysis of data. In addition, X-CSIT will be released as a standalone, open source version for other users, collaborations and groups intending to create simulations of their own detectors.

Monte Carlo simulation of x-ray spectra in mammography

Energy Technology Data Exchange (ETDEWEB)

Ng, K.P. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China). E-mail: benngkp at netvigator.com; Kwok, C.S.; Ng, K.P.; Tang, F.H. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

2000-05-01

A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The {chi}{sup 2} test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the {chi}{sup 2} test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

Monte Carlo simulation of x-ray spectra in mammography

International Nuclear Information System (INIS)

Ng, K.P.

2000-01-01

A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The χ 2 test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the χ 2 test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

Simulation of a dense plasma focus x-ray source

International Nuclear Information System (INIS)

Stark, R.A.

1994-01-01

The authors are performing simulations of the magnetohydrodynamics of a Dense Plasma Focus (DPF) x-ray source located at Science Research Laboratory (SRL), Alameda, CA, in order to optimize its performance. The SRL DPF, which was developed as a compact source for x-ray lithography, operates at 20 Hz, giving x-ray power (9--14 Angstroms) of 500 W using neon gas. The simulations are performed with the two dimensional MHD code MACH2, developed by Mission Research Corporation, with a steady state corona model as the equation of state. The results of studies of the sensitivity of x-ray output to charging voltage and current, and to initial gas density will be presented. These studies should indicate ways to optimize x-ray production efficiency. Simulations of various inner electrode configurations will also be presented

A cosmic ALP background and the cluster soft X-ray excess in A665, A2199 and A2255

Energy Technology Data Exchange (ETDEWEB)

Powell, Andrew J., E-mail: Andrew.Powell2@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP (United Kingdom)

2015-09-01

It has been proposed that an excess in soft X-ray emission observed from many galaxy clusters can be explained by conversion into photons of axion-like particles (ALPs) in the cluster's magnetic field. Previously it has been shown that conversion of this primordially-generated background of relativistic ALPs—a cosmic ALP background (CAB)—can explain the observed soft X-ray excess in both the centre and the outskirts of the Coma cluster. Here we extend this work to the three clusters A665, A2199 and A2255. We use a stochastic, power law model of the cluster magnetic field to numerically calculate ALP-photon conversion probabilities to predict the CAB-generated soft X-ray flux in these clusters. The simulated magnetic fields include models with non-standard (i.e. not turbulent Kolmogorov) power spectra, the index of the spectrum changes from cluster to cluster and even within the cluster A2255. We compare this flux to ROSAT PSPC observations of the three clusters, and use these observations to constrain the CAB parameter space. Assuming these non-standard magnetic field power spectra are valid, we find the CAB can reproduce the magnitude of the observed excess in A2199 and A2255 for the same CAB parameters that match the observed soft excess in the Coma cluster. We also find good fit to the morphology of the excesses in these clusters. Simulation of CAB conversion in the cluster A665 is in mild tension with the other clusters due to producing a small but observable excess at large radii where none is observed. This tension is alleviated considering the uncertainty on predicting the count rate in the ROSAT detector, and on the systematics affecting the magnetic field determination. Overall we find good agreement between the CAB parameters for the four clusters studied so far.

A cosmic ALP background and the cluster soft X-ray excess in A665, A2199 and A2255

International Nuclear Information System (INIS)

Powell, Andrew J.

2015-01-01

It has been proposed that an excess in soft X-ray emission observed from many galaxy clusters can be explained by conversion into photons of axion-like particles (ALPs) in the cluster's magnetic field. Previously it has been shown that conversion of this primordially-generated background of relativistic ALPs—a cosmic ALP background (CAB)—can explain the observed soft X-ray excess in both the centre and the outskirts of the Coma cluster. Here we extend this work to the three clusters A665, A2199 and A2255. We use a stochastic, power law model of the cluster magnetic field to numerically calculate ALP-photon conversion probabilities to predict the CAB-generated soft X-ray flux in these clusters. The simulated magnetic fields include models with non-standard (i.e. not turbulent Kolmogorov) power spectra, the index of the spectrum changes from cluster to cluster and even within the cluster A2255. We compare this flux to ROSAT PSPC observations of the three clusters, and use these observations to constrain the CAB parameter space. Assuming these non-standard magnetic field power spectra are valid, we find the CAB can reproduce the magnitude of the observed excess in A2199 and A2255 for the same CAB parameters that match the observed soft excess in the Coma cluster. We also find good fit to the morphology of the excesses in these clusters. Simulation of CAB conversion in the cluster A665 is in mild tension with the other clusters due to producing a small but observable excess at large radii where none is observed. This tension is alleviated considering the uncertainty on predicting the count rate in the ROSAT detector, and on the systematics affecting the magnetic field determination. Overall we find good agreement between the CAB parameters for the four clusters studied so far

Resolving the origin of the diffuse soft X-ray background

Energy Technology Data Exchange (ETDEWEB)

Smith, Randall K.; Foster, Adam R.; Edgar, Richard J.; Brickhouse, Nancy S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138 (United States)

2014-05-20

The ubiquitous diffuse soft (1/4 keV) X-ray background was one of the earliest discoveries of X-ray astronomy. At least some of the emission may arise from charge exchange between solar wind ions and neutral atoms in the heliosphere, but no detailed models have been fit to the available data. Here, we report on a new model for charge exchange in the solar wind, which, when combined with a diffuse hot plasma component, filling the Local Cavity provides a good fit to the only available high-resolution soft X-ray and extreme ultraviolet spectra using plausible parameters for the solar wind. The implied hot plasma component is in pressure equilibrium with the local cloud that surrounds the solar system, creating for the first time a self-consistent picture of the local interstellar medium.

Recording soft-X-ray images with photographic materials at large gamma background

International Nuclear Information System (INIS)

Izrailev, I.M.

1993-01-01

The sensitivity of photographic materials to soft X-rays and 60 Co γ-quanta when developed by visible light and a chemical developer is investigated. When the photographic paper is developed by visible light, its sensitivity is reduced by 200-300 times independent of the quantum energy. This method allows an X-ray image to be recorded even when there is γ-background of 10 5 R. 2 refs., 1 tab

Scientific requirements for studying the composition of the X-ray background

International Nuclear Information System (INIS)

Griffiths, R.E.

1990-01-01

A major goal of X-ray astronomy for the 21st century is to make significant contributions to observational cosmology, via the detection of objects at fluxes of 10 -19 ergs cm -2 s -1 , such as the star-forming galaxies at moderate redshift which make up the x-ray background. In order to meet this sensitivity requirement, which is at least two to three orders of magnitude deeper than AXAF, the challenge for the remainder of the present century is to develop the economical and practicable technology of very large mirror arrays

An Einstein survey of the 1 keV soft X-ray background in the Galactic plane

Science.gov (United States)

Stanford, John M.; Caillault, Jean-Pierre

1994-01-01

We have analyzed 56 Einstein Observatory Imaging Proportional Counter (IPC) observations within +/- 3 deg of the Galactic plane in order to determine the low-latitude soft X-ray background flux in the 0.56-1.73 keV band. Any detected X-ray point source which fell within our regions of study was removed from the image, enabling us to present maps of the background flux as a function of Galactic latitude along 18 meridians. These maps reveal considerable structure to the background in the Galactic plane on an angular scale of approximately 1 deg. Our results are compared with those of an earlier study of the 1 keV X-ray background along l = 25 deg by Kahn & Caillault. The double-peaked structure they found is not discernible in our results, possibly because of the presence of solar backscattered flux in their data. A model which takes into account contributions to the background by extragalactic and stellar sources, the distribution of both atomic and molecular absorbing material with the Galaxy, the energy dependence of the cross section for absorption of X-rays, and the energy dependence of the detector has been constructed and fitted to these new data to derive constraints on the scale height, temperature, and volume emissivity of the unaccounted-for X-ray-emitting material. The results of this model along l = 25 deg are roughly similar to those of the model of Kahn & Caillault along the same meridian.

Talbot Carpet Simulation for X-ray grating interferometer

Energy Technology Data Exchange (ETDEWEB)

Kim, Youngju; Oh, Ohsung; Jeong, Hanseong; Kim, Jeongho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Kim, Jongyul; Moon, Myungkook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

In this study, Talbot carpet simulator has been developed to visualize the X-ray grating interference patterns in grating interferometer. We have simulated X-ray interference for a variety of simulations and demonstrated a few examples in this summary. Grating interferometer produces interference of X-ray called Talbot pattern with gratings manufactured in micro scale. Talbot pattern is self-images of phase grating which develops interference as beam splitter that is one of gratings consisted of interferometer. As the other gratings, there are source grating makes coherence and analyze grating is used to analyze interference onto detector. Talbot carpet has been studied as the beam behavior which is distinguished with common X-ray imaging systems. It is helpful to understand grating interferometer and possible to expect beams' oscillation for designing theoretically. We confirm pattern has periodicity produced by interference after pi and pi/2 phase grating and changes in the perpendicular direction to entrance face according to phase objects.

The inception of pulsed discharges in air: simulations in background fields above and below breakdown

Science.gov (United States)

Sun, Anbang; Teunissen, Jannis; Ebert, Ute

2014-11-01

We investigate discharge inception in air, in uniform background electric fields above and below the breakdown threshold. We perform 3D particle simulations that include a natural level of background ionization in the form of positive and \\text{O}2- ions. In background fields below breakdown, we use a strongly ionized seed of electrons and positive ions to enhance the field locally. In the region of enhanced field, we observe the growth of positive streamers, as in previous simulations with 2D plasma fluid models. The inclusion of background ionization has little effect in this case. When the background field is above the breakdown threshold, the situation is very different. Electrons can then detach from \\text{O}2- and start ionization avalanches in the whole volume. These avalanches together create one extended discharge, in contrast to the ‘double-headed’ streamers found in many fluid simulations.

Research on cloud background infrared radiation simulation based on fractal and statistical data

Science.gov (United States)

Liu, Xingrun; Xu, Qingshan; Li, Xia; Wu, Kaifeng; Dong, Yanbing

2018-02-01

Cloud is an important natural phenomenon, and its radiation causes serious interference to infrared detector. Based on fractal and statistical data, a method is proposed to realize cloud background simulation, and cloud infrared radiation data field is assigned using satellite radiation data of cloud. A cloud infrared radiation simulation model is established using matlab, and it can generate cloud background infrared images for different cloud types (low cloud, middle cloud, and high cloud) in different months, bands and sensor zenith angles.

Surface roughness evaluation on mandrels and mirror shells for future X-ray telescopes

Science.gov (United States)

Sironi, Giorgia; Spiga, D.

2008-07-01

More X-ray missions that will be operating in near future, like particular SIMBOL-X, e-Rosita, Con-X/HXT, SVOM/XIAO and Polar-X, will be based on focusing optics manufactured by means of the Ni electroforming replication technique. This production method has already been successfully exploited for SAX, XMM and Swift-XRT. Optical surfaces for X-ray reflection have to be as smooth as possible also at high spatial frequencies. Hence it will be crucial to take under control microroughness in order to reduce the scattering effects. A high rms microroughness would cause the degradation of the angular resolution and loss of effective area. Stringent requirements have therefore to be fixed for mirror shells surface roughness depending on the specific energy range investigated, and roughness evolution has to be carefully monitored during the subsequent steps of the mirror-shells realization. This means to study the roughness evolution in the chain mandrel, mirror shells, multilayer deposition and also the degradation of mandrel roughness following iterated replicas. Such a study allows inferring which phases of production are the major responsible of the roughness growth and could help to find solutions optimizing the involved processes. The exposed study is carried out in the context of the technological consolidation related to SIMBOL-X, along with a systematic metrological study of mandrels and mirror shells. To monitor the roughness increase following each replica, a multiinstrumental approach was adopted: microprofiles were analysed by means of their Power Spectral Density (PSD) in the spatial frequency range 1000-0.01 μm. This enables the direct comparison of roughness data taken with instruments characterized by different operative ranges of frequencies, and in particular optical interferometers and Atomic Force Microscopes. The performed analysis allowed us to set realistic specifications on the mandrel roughness to be achieved, and to suggest a limit for the

Modeling of neutron induced backgrounds in x-ray framing cameras

Energy Technology Data Exchange (ETDEWEB)

Hagmann, C.; Izumi, N.; Bell, P.; Bradley, D.; Conder, A.; Eckart, M.; Khater, H.; Koch, J.; Moody, J.; Stone, G. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2010-10-15

Fast neutrons from inertial confinement fusion implosions pose a severe background to conventional multichannel plate (MCP)-based x-ray framing cameras for deuterium-tritium yields >10{sup 13}. Nuclear reactions of neutrons in photosensitive elements (charge coupled device or film) cause some of the image noise. In addition, inelastic neutron collisions in the detector and nearby components create a large gamma pulse. The background from the resulting secondary charged particles is twofold: (1) production of light through the Cherenkov effect in optical components and by excitation of the MCP phosphor and (2) direct excitation of the photosensitive elements. We give theoretical estimates of the various contributions to the overall noise and present mitigation strategies for operating in high yield environments.

The background counting rates in a balloon borne hard X-ray telescope

International Nuclear Information System (INIS)

Dean, A.J.; Dipper, N.A.; Lewis, R.A.

1986-01-01

A detailed Monte Carlo model of a hard (20-300 keV) X-ray astronomical telescope has been developed in order to calculate the energy loss distribution of the unwanted background noise events in the prime detection elements. The spectral distributions of the background rates measured at balloon altitudes over Palestine, Texas are compared to the predictions of the theoretical model. Good agreement has been found in terms of both the overall intensity level as well as the spectral distribution. (orig.)

Hard X-ray Flux from Low-Mass Stars in the Cygnus OB2 Association

Science.gov (United States)

Caramazza, M.; Drake, J. J.; Micela, G.; Flaccomio, E.

2009-05-01

We investigate the X-ray emission in the 20-40 keV band expected from the flaring low-mass stellar population in Cygnus OB2 assuming that the observed soft X-ray emission is due to a superposition of flares and that the ratio of hard X-ray to soft X-ray emission is described by a scaling found for solar flares by Isola and co-workers. We estimate a low-mass stellar hard X-ray flux in the 20-40 keV band in the range ~7×1031-7×1033 erg/s and speculate the limit of this values. Hard X-ray emission could lie at a level not much below the current observed flux upper limits for Cygnus OB2. Simbol-X, with its broad energy band (10-100 keV) and its sensitivity should be able to detect this emission and would provide insights into the hard X-ray production of flares on pre-main sequence stars.

Air shower simulation for background estimation in muon tomography of volcanoes

Directory of Open Access Journals (Sweden)

S. Béné

2013-01-01

Full Text Available One of the main sources of background for the radiography of volcanoes using atmospheric muons comes from the accidental coincidences produced in the muon telescopes by charged particles belonging to the air shower generated by the primary cosmic ray. In order to quantify this background effect, Monte Carlo simulations of the showers and of the detector are developed by the TOMUVOL collaboration. As a first step, the atmospheric showers were simulated and investigated using two Monte Carlo packages, CORSIKA and GEANT4. We compared the results provided by the two programs for the muonic component of vertical proton-induced showers at three energies: 1, 10 and 100 TeV. We found that the spatial distribution and energy spectrum of the muons were in good agreement for the two codes.

Filter-fluorescer x-ray spectrometer using solid state detectors for γ-ray background reduction

International Nuclear Information System (INIS)

Yokoi, Takashi; Kitagawa, Yoneyoshi; Shiraga, Hiroyuki; Matsunaga, Hirohide; Kato, Yoshiaki; Yamanaka, Chiyoe.

1986-01-01

Filter-fluorescer x-ray spectrometer using solid state photo-detectors instead of the photomultiplier tubes in order to reduce the γ-ray background noise is reported. A significant reduction of the γ-ray background noise is expected, because solid state photo-detectors are very small in size compared with the photomultiplier tubes. It has been confirmed that the γ-ray background is reduced in the target irradiation experiments with the Gekko MII glass laser. (author)

Multiple wavelength spectral system simulating background light noise environment in satellite laser communications

Science.gov (United States)

Lu, Wei; Sun, Jianfeng; Hou, Peipei; Xu, Qian; Xi, Yueli; Zhou, Yu; Zhu, Funan; Liu, Liren

2017-08-01

Performance of satellite laser communications between GEO and LEO satellites can be influenced by background light noise appeared in the field of view due to sunlight or planets and some comets. Such influences should be studied on the ground testing platform before the space application. In this paper, we introduce a simulator that can simulate the real case of background light noise in space environment during the data talking via laser beam between two lonely satellites. This simulator can not only simulate the effect of multi-wavelength spectrum, but also the effects of adjustable angles of field-of-view, large range of adjustable optical power and adjustable deflection speeds of light noise in space environment. We integrate these functions into a device with small and compact size for easily mobile use. Software control function is also achieved via personal computer to adjust these functions arbitrarily. Keywords:

X-ray clusters in a cold dark matter + lambda universe: A direct, large-scale, high-resolution, hydrodynamic simulation

Science.gov (United States)

Cen, Renyue; Ostriker, Jeremiah P.

1994-01-01

A new, three-dimensional, shock-capturing, hydrodynamic code is utilized to determine the distribution of hot gas in a cold dark matter (CDM) + lambda model universe. Periodic boundary conditions are assumed: a box with size 85/h Mpc, having cell size 0.31/h Mpc, is followed in a simulation with 270(exp 3) = 10(exp 7.3) cells. We adopt omega = 0.45, lambda = 0.55, h identically equal to H/100 km/s/Mpc = 0.6, and then, from the cosmic background explorer (COBE) and light element nucleosynthesis, sigma(sub 8) = 0.77, omega(sub b) = 0.043. We identify the X-ray emitting clusters in the simulation box, compute the luminosity function at several wavelength bands, the temperature function and estimated sizes, as well as the evolution of these quantities with redshift. This open model succeeds in matching local observations of clusters in contrast to the standard omega = 1, CDM model, which fails. It predicts an order of magnitude decline in the number density of bright (h nu = 2-10 keV) clusters from z = 0 to z = 2 in contrast to a slight increase in the number density for standard omega = 1, CDM model. This COBE-normalized CDM + lambda model produces approximately the same number of X-ray clusters having L(sub x) greater than 10(exp 43) erg/s as observed. The background radiation field at 1 keV due to clusters is approximately the observed background which, after correction for numerical effects, again indicates that the model is consistent with observations.

Background simulation for the COBRA-experiment

Energy Technology Data Exchange (ETDEWEB)

Quante, Thomas [TU Dortmund, Institut fuer Physik (Germany); Collaboration: COBRA-Collaboration

2015-07-01

COBRA is a next-generation experiment searching for neutrinoless double beta (0νββ) decay using CdZnTe semiconductor detectors. The main focus is on {sup 116}Cd, with a Q-value of 2813.5 keV well above the highest dominant naturally occurring gamma lines. By measuring the half-life of the 0νββ decay, it is possible to clarify the nature of the neutrino as either Dirac or Majorana particle and furthermore to determine the effective Majorana mass. COBRA is currently in the demonstrator phase to study possible background contributions and gain information about the longterm stability of the used detectors. For this purpose a demonstrator array made up of 64 Cadmium-Zinc-Telluride (CdZnTe) semiconductor detectors in coplanar grid configuration was designed and realised at the Gran Sasso Underground laboratory (LNGS) in Italy. Simulations of the whole demonstrator setup are ongoing to reproduce the measured spectra for each detector. This is done in two steps. The first uses the Geant4 based framework VENOM for tracking and energy deposition inside each detector. Detector effects like the energy resolution and electron trapping have to be applied in the second step. The used detector geometry has to be verified against calibration measurements. This talk gives an overview of the current simulation status.

X-Rays from NGC 3256: High-Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X-Ray Background

International Nuclear Information System (INIS)

Moran, Edward C.; Lehnert, Matthew D.; Helfand, David J.

1999-01-01

The infrared-luminous galaxy NGC 3256 is a classic example of a merger-induced nuclear starburst system. We find here that it is the most X-ray-luminous star-forming galaxy yet detected (L 0.5-10keV =1.6x10 42 ergs s-1). Long-slit optical spectroscopy and a deep, high-resolution ROSAT X-ray image show that the starburst is driving a ''superwind'' which accounts for ∼20% of the observed soft X-ray emission. Analysis of X-ray spectral data from ASCA indicates this gas has a characteristic temperature of kT≅0.3 keV. Our model for the broadband X-ray emission of NGC 3256 contains two additional components: a warm thermal plasma (kT≅0.8 keV) associated with the central starburst, and a hard power-law component with an energy index of α X ≅0.7. We discuss the energy budget for the two thermal plasmas and find that the input of mechanical energy from the starburst is more than sufficient to sustain the observed level of emission. We also examine possible origins for the power-law component, concluding that neither a buried AGN nor the expected population of high-mass X-ray binaries can account for this emission. Inverse Compton scattering, involving the galaxy's copious flux of infrared photons and the relativistic electrons produced by supernovae, is likely to make a substantial contribution to the hard X-ray flux. Such a model is consistent with the observed radio and IR fluxes and the radio and X-ray spectral indices. We explore the role of X-ray-luminous starbursts in the production of the cosmic X-ray background radiation. The number counts and spectral index distribution of the faint radio source population, thought to be dominated by star-forming galaxies, suggest that a significant fraction of the hard X-ray background could arise from starbursts at moderate redshift. (c) (c) 1999. The American Astronomical Society

High-z X-ray Obscured Quasars in Galaxies with Extreme Mid-IR/Optical Colors

Science.gov (United States)

Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Grappioni, C.

2009-05-01

Extreme Optical/Mid-IR color cuts have been used to uncover a population of dust-enshrouded, mid-IR luminous galaxies at high redshifts. Several lines of evidence point towards the presence of an heavily absorbed, possibly Compton-thick quasar at the heart of these systems. Nonetheless, the X-ray spectral properties of these intriguing sources still remain largely unexplored. Here we present an X-ray spectroscopic study of a large sample of 44 extreme dust-obscured galaxies (EDOGs) with F24 μm/FR>2000 and F24 μm>1.3 mJy selected from a 6 deg2 region in the SWIRE fields. The application of our selection criteria to a wide area survey has been capable of unveiling a population of X-ray luminous, absorbed z>1 quasars which is mostly missed in the traditional optical/X-ray surveys performed so far. Advances in the understanding of the X-ray properties of these recently-discovered sources by Simbol-X observations will be also discussed.

Analysis of signal to background ratio in synchrotron radiation X-ray fluorescence

International Nuclear Information System (INIS)

Sakurai, Kenji; Gohshi, Yohichi; Iida, Atsuo.

1988-01-01

The signal to background (S/B) ratio in energy dispersive X-ray fluorescence using synchrotron radiation (SR) was quantitatively analyzed. The S/B ratio, which has been significantly improved by taking advantage of the polarized nature of SR, was found to be strongly dependent on geometrical factors of the measurement system. From the analysis on the origin of the scattered background, the dependence of the S/B ratio on the geometry was quantitatively explained, mainly by the polarization properties of SR. Experimental conditions could be optimized by adjusting the degree of polarization of the incident beam and the detector solid angle. (author)

Background estimation in short-wave region during determination of total sample composition by x-ray fluorescence method

International Nuclear Information System (INIS)

Simakov, V.A.; Kordyukov, S.V.; Petrov, E.N.

1988-01-01

Method of background estimation in short-wave spectral region during determination of total sample composition by X-ray fluorescence method is described. 13 types of different rocks with considerable variations of base composition and Zr, Nb, Th, U content below 7x10 -3 % are investigated. The suggested method of background accounting provides for a less statistical error of the background estimation than direct isolated measurement and reliability of its determination in a short-wave region independent on the sample base. Possibilities of suggested method for artificial mixtures conforming by the content of main component to technological concemtrates - niobium, zirconium, tantalum are estimated

Monte Carlo simulation of dose enhancement effect of X-ray at Au/Si interface

International Nuclear Information System (INIS)

Wu Zhengxin; He Chengfa; Lu Wu; Guo Qi; Yu Xin; Zhang Lei; Deng Wei; Zheng Qiwen; ARKIN Abulim

2013-01-01

Background: The dose enhancement factor of X-ray was found in 1970s, because of its bad damage to electronic devices. Purpose: This paper is mainly to calculate the dose-enhancement factor at Au/Si interfaces. Methods: The gradient distribution of dose with X-rays has been studied at and near the interface of Au/Si by Monte-Carlo simulation of particle transportation. The mechanism of dose enhancement is discussed based on the principles of interaction of photon with matter. A 3D Au/Si model has been established by MCNP5 program and the dose-enhancement factors of different thicknesses Au/Si interfaces were calculated by Monte Carlo method. Results: The calculated results demonstrate that there exists a stronger dose-enhancement in the Si side near the interface when the energy of X-ray is 30-300 keV. Conclusions: When the thickness of Au is 0-10 μm, dose-enhancement factor of X-ray increases along with the increase of the thickness of Au, when the thickness of Au exceeds 10 μm, dose-enhancement factor of X-ray decreases along with the increase of the thickness of Au. (authors)

PROSES REPRESENTASI SIMBOL MATEMATIKA PADA PROSES BERMAIN ANAK TK

Directory of Open Access Journals (Sweden)

Ari Kusuma Sulyandari

2017-01-01

Full Text Available This study aims to determine the representation of children in kindergartens of the objects and symbols of numbers 1 to 10 when playing activities. So the mathematical activity in appropriate with the child's development. This study uses qualitative descriptive by Moleong. The collection of data through observation, interviews, photo and recording. To check the validity of researchers used data triangulation of data sources, theory and methodology. Results of the study is that children need visual in process representation. They need to understand the concept of visualization when many objects, counting objects, understand the numbers 1 to 10. Children are not able to think abstractly. Representation of children has not been perfect. Method of learning in kindergarten helps learning to count and recognize numbers. Especially if done with playing. Tujuan penelitian ini untuk mengetahui proses representasi anak TK pada simbol matematika bilangan asli 1 sampai 10 pada proses bermain sehingga pembelajaran matematika sesuai dengan perkembangan anak. Metode penelitian yang digunakan adalah deskriptif kualitatif. Teknik pengumpulan data menggunakan teknik observasi, wawancara, dan dokumentasi berupa foto serta perekaman. Teknik analisis data yang digunakan pada saat penelitian adalah analisis deskriptif untuk mengecek keabsahan peneliti menggunakan data triangulasi sumber data, teori, dan metodologi. Hasil penelitian menunjukkan bahwa anak usia TK membutuhkan visual dalam aktivitas representasi. Anak-anak membutuhkan bantuan visual saat memahami konsep banyak benda, menghitung benda, memahami bilangan 1 sampai 10. Hal ini dikarenakan anak usia TK masih belum dapat berpikir secara abstrak sehingga representasi anak usia TK masih belum sempurna. Penggunaan metode pembelajaran tematik terpadu di TK mempermudah pembelajaran berhitung dan mengenal angka terlebih jika dilakukan dengan bermain.

Baltimore Harbor and Channels Deepening Study; Chesapeake Bay Hydraulic Model Investigation.

Science.gov (United States)

1982-02-01

SYMBOL DEPTH 0 ( a 20 - BASE 25 - SIMBOL DEPTH x 4 0 13 15 S20 P PL AN -5 PL QN - RSF -10 SU IF PCE 0 MIOOLF BOTTOM L - 1 A 1_ I I I I I 0 Joe Pee 3e...DAYS Plate 86. Sta CBC-1 salinity time-history lee a lee 266 306 4e6 5ee le ie ... e SOLA0R DASs 5 SIMBOL DEPTHI x 2 O 14N 10 BASE SYMBOL DEPTH )1 2 0

Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress

Science.gov (United States)

2016-04-05

Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress Ronald O’Rourke Specialist in Naval...Affairs April 5, 2016 Congressional Research Service 7-5700 www.crs.gov R41129 Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine...1,091.1 million in research and development funding for the Ohio replacement program (ORP), a program to design and build a new class of 12 ballistic

Three spin string configuration in γ-Deformed AdS5xS5 background

International Nuclear Information System (INIS)

Bobev, N.; Rashkov, R.; Dimov, H.

2006-01-01

The aim of this paper is to investigate semiclassical rotating string configurations in the recently found Lunin-Maldacena background. This background is conjectured to be dual to the Leigh-Strassler β-deformation of N = 4 SYM and therefore a good laboratory for tests of the AdS/CFT correspondence beyond the well explored AdS 5 xS 5 case. We consider different multispin configurations of rotating strings by allowing the strings to move in both the AdS 5 and the deformed S 5 part of the Lunin-Maldacena background. For all of these configurations we compute the string energy in terms of the angular momenta and the string winding numbers and thus provide the possibility of reproducing our results from a computation of the anomalous dimension of the corresponding dilatation operator. This can be achieved by means of the Bethe ansatz techniques for the relevant sectors of the corresponding Yang-Mills theory. We also compare our results to those for multispin rotating strings on AdS 5 xS 5 . (authors)

Identification of simulated microcalcifications in white noise and mammographic backgrounds

International Nuclear Information System (INIS)

Reiser, Ingrid; Nishikawa, Robert M.

2006-01-01

This work investigates human performance in discriminating between differently shaped simulated microcalcifications embedded in white noise or mammographic backgrounds. Human performance was determined through two alternative forced-choice (2-AFC) experiments. The signals used were computer-generated simple shapes that were designed such that they had equal signal energy. This assured equal detectability. For experiments involving mammographic backgrounds, signals were blurred to account for the imaging system modulation transfer function (MTF). White noise backgrounds were computer generated; anatomic background patches were extracted from normal mammograms. We compared human performance levels as a function of signal energy in the expected difference template. In the discrimination task, the expected difference template is the difference between the two signals shown. In white noise backgrounds, human performance in the discrimination task was degraded compared to the detection task. In mammographic backgrounds, human performance in the discrimination task exceeded that of the detection task. This indicates that human observers do not follow the optimum decision strategy of correlating the expected signal template with the image. Human observer performance was qualitatively reproduced by non-prewhitening with eye filter (NPWE) model observer calculations, in which spatial uncertainty was explicitly included by shifting the locations of the expected difference templates. The results indicate that human strategy in the discrimination task may be to match individual signal templates with the image individually, rather than to perform template matching between the expected difference template and the image

Simulating cosmic microwave background maps in multiconnected spaces

International Nuclear Information System (INIS)

Riazuelo, Alain; Uzan, Jean-Philippe; Lehoucq, Roland; Weeks, Jeffrey

2004-01-01

This paper describes the computation of cosmic microwave background (CMB) anisotropies in a universe with multiconnected spatial sections and focuses on the implementation of the topology in standard CMB computer codes. The key ingredient is the computation of the eigenmodes of the Laplacian with boundary conditions compatible with multiconnected space topology. The correlators of the coefficients of the decomposition of the temperature fluctuation in spherical harmonics are computed and examples are given for spatially flat spaces and one family of spherical spaces, namely, the lens spaces. Under the hypothesis of Gaussian initial conditions, these correlators encode all the topological information of the CMB and suffice to simulate CMB maps

QCD jet simulation with CMS at LHC and background studies to H to gamma gamma process

CERN Document Server

Litvin, V; Shevchenko, S; Wisniewski, N

2002-01-01

We have simulated and reconstructed one million of QCD jet events. This study was done with CMS full detector simulation, based on GEANT3 package, and object-oriented CMS C++ reconstruction program. The understanding of QCD jet background is important for the Higgs search in two-photon decay mode. The comparison with other types of backgrounds was also done. It was shown that the isolation tools were important ones to isolate the signal process from the huge background one. Using the isolation criteria based on the information from PbWO /sub 4/ electromagnetic calorimeter and the tracker we were able to reduce the QCD jet background to 15% of the total one. (9 refs).

The MCNP simulation of the X-ray leakage of X-ray security inspection equipment

International Nuclear Information System (INIS)

Wang Kai; Liu Bin; Hu Wenchao; Zhao Wei

2011-01-01

Objective: To simulate the radiation leakage of the X-ray security inspection equipment used in the subways stations. Methods: We use the MCNP4C code to simulate the X-ray leakage of the equipment during the working process. Result: the biggest amount of radiation received by the body is 8.26 μSv/a, however, if the Lead screens of the X-ray security equipment is intact, the amount of radiation received by the body is only 0.0727 μSv/a. The final. Conclusions: When the baggage get in /out the X-ray security inspection equipment, the gas in Lead screens was made, and then the amount of radiation received by human body increased; The amount of radiation received by the body is close to but still below 10 μSv/a which is the exemption criteria set by the 'safety of radiation sources of ionizing radiation protection and basic standards'(GB18871-2002). (authors)

Simulation of high-resolution X-ray microscopic images for improved alignment

International Nuclear Information System (INIS)

Song Xiangxia; Zhang Xiaobo; Liu Gang; Cheng Xianchao; Li Wenjie; Guan Yong; Liu Ying; Xiong Ying; Tian Yangchao

2011-01-01

The introduction of precision optical elements to X-ray microscopes necessitates fine realignment to achieve optimal high-resolution imaging. In this paper, we demonstrate a numerical method for simulating image formation that facilitates alignment of the source, condenser, objective lens, and CCD camera. This algorithm, based on ray-tracing and Rayleigh-Sommerfeld diffraction theory, is applied to simulate the X-ray microscope beamline U7A of National Synchrotron Radiation Laboratory (NSRL). The simulations and imaging experiments show that the algorithm is useful for guiding experimental adjustments. Our alignment simulation method is an essential tool for the transmission X-ray microscope (TXM) with optical elements and may also be useful for the alignment of optical components in other modes of microscopy.

A color gradient in the soft X-ray diffuse background

International Nuclear Information System (INIS)

Snowden, S.L.; Schmitt, J.H.M.M.; Edwards, B.C.

1990-01-01

It is shown that the deviations of the soft X-ray diffuse background B band to C band intensity ratio from a constant value can be described as a simple dipole-like variation across the sky. In terms of the observed Wisconsin B/C band intensity ratio, the mean value is 0.355, the dipole magnitude is 0.106, and the positive dipole axis points toward l = 168.7 deg, b = 11.2 deg, almost in the galactic anticenter direction. This gradient in the spectral hardness can be due to several causes; the simplest is a temperature gradient in the X-ray emitting plasma of the local cavity from about 10 exp 6.2 K toward the galactic center to about 10 exp 5.9 K in the anticenter direction. While the physical origin of such a temperature gradient is uncertain, the alignment of the dipole with the higher temperature (and absorbed) Loop I region may be significant. 25 refs

A color gradient in the soft X-ray diffuse background

Science.gov (United States)

Snowden, S. L.; Schmitt, J. H. M. M.; Edwards, B. C.

1990-01-01

It is shown that the deviations of the soft X-ray diffuse background B band to C band intensity ratio from a constant value can be described as a simple dipole-like variation across the sky. In terms of the observed Wisconsin B/C band intensity ratio, the mean value is 0.355, the dipole magnitude is 0.106, and the positive dipole axis points toward l = 168.7 deg, b = 11.2 deg, almost in the galactic anticenter direction. This gradient in the spectral hardness can be due to several causes; the simplest is a temperature gradient in the X-ray emitting plasma of the local cavity from about 10 exp 6.2 K toward the galactic center to about 10 exp 5.9 K in the anticenter direction. While the physical origin of such a temperature gradient is uncertain, the alignment of the dipole with the higher temperature (and absorbed) Loop I region may be significant.

Infrared-faint radio sources: a cosmological view. AGN number counts, the cosmic X-ray background and SMBH formation

Science.gov (United States)

Zinn, P.-C.; Middelberg, E.; Ibar, E.

2011-07-01

Context. Infrared-faint radio sources (IFRS) are extragalactic emitters clearly detected at radio wavelengths but barely detected or undetected at optical and infrared wavelengths, with 5σ sensitivities as low as 1 μJy. Aims: Spectral energy distribution (hereafter SED) modelling and analyses of their radio properties indicate that IFRS are consistent with a population of (potentially extremely obscured) high-redshift AGN at 3 ≤ z ≤ 6. We demonstrate some astrophysical implications of this population and compare them to predictions from models of galaxy evolution and structure formation. Methods: We compiled a list of IFRS from four deep extragalactic surveys and extrapolated the IFRS number density to a survey-independent value of (30.8 ± 15.0) deg-2. We computed the IFRS contribution to the total number of AGN in the Universe to account for the cosmic X-ray background. By estimating the black hole mass contained in IFRS, we present conclusions for the SMBH mass density in the early universe and compare it to relevant simulations of structure formation after the Big Bang. Results: The number density of AGN derived from the IFRS density was found to be ~310 deg-2, which is equivalent to a SMBH mass density of the order of 103 M⊙ Mpc-3 in the redshift range 3 ≤ z ≤ 6. This produces an X-ray flux of 9 × 10-16 W m-2 deg-2 in the 0.5-2.0 keV band and 3 × 10-15 W m-2 deg-2 in the 2.0-10 keV band, in agreement with the missing unresolved components of the Cosmic X-ray Background. To address SMBH formation after the Big Bang we invoke a scenario involving both halo gas accretion and major mergers.

Cosmological Implications of the Effects of X-Ray Clusters on the Cosmic Microwave Background

Science.gov (United States)

Forman, William R.

1996-01-01

We have been carrying forward a program to confront X-ray observations of clusters and their evolution as derived from X-ray observatories with observations of the cosmic microwave background radiation (CMBR). In addition to the material covered in our previous reports (including three published papers), most recently we have explored the effects of a cosmological constant on the predicted Sunyaev-Zel'dovich effect from the ensemble of clusters. In this report we summarize that work from which a paper will be prepared.

Feasibility of using continuous X-ray to simulate cable response under X-ray environment

International Nuclear Information System (INIS)

Ma Liang; Zhou Hui; Cheng Yinhui; Wu Wei; Li Jinxi; Zhao Mo; Guo Jinghai

2014-01-01

The mechanism and simulating method of cable response induced by X-ray were researched, and the relationship of cable response irradiated by continuous and pulsed X-ray was analyzed. A one-dimension model of strip line irradiation response of X-ray was given, which includes the gap between cable shield and dielectric, and induced conductivity in cable dielectric. The calculation result using the model indicates that the cable responses of continuous and rectangular-pulsed X-ray have the similar current waveform and the same gap voltages. Therefore, continuous X-ray can be used to research some cable responses of pulsed X-ray irradiation under the mechanism described in the one-dimension model. (authors)

Superparticle and superstring in AdS3 x S3 Ramond--Ramond background in the light-cone gauge

International Nuclear Information System (INIS)

Metsaev, R. R.; Tseytlin, A. A.

2001-01-01

We discuss superparticle and superstring dynamics in AdS 3 x S 3 supported by R--R 3-form background using light-cone gauge approach. Starting with the superalgebra psu(1,1|2)(circle plus)psu (1,1|2) representing the basic symmetry of this background we find the light-cone superparticle Hamiltonian. We determine the harmonic decomposition of light-cone superfield describing fluctuations of type IIB supergravity fields expanded near AdS 3 x S 3 background and thus the corresponding Kaluza--Klein spectrum. We fix the fermionic and bosonic light-cone gauges in the covariant Green--Schwarz AdS 3 x S 3 superstring action and find the corresponding light-cone string Hamiltonian. We also obtain a realization of the generators of psu(1,1|2)(circle plus)psu (1,1|2) in terms of the superstring 2-d fields in the light-cone gauge

SISTEMUL SIMBOLIC – REPER EDUCAŢIONAL

Directory of Open Access Journals (Sweden)

Alina ŢICĂU

2017-03-01

Full Text Available Istoria tradiţională dezvăluie picturi rupestre, semne hieroglifice şi texte sacre care reliefează o serie de expresii ale vieţii cotidiene. În jurul acestora, oamenii îşi organizează viaţa, îşi fac un nivel de expectanţă, creează valori educaţionale, spirituale şi sociale. Un anumit gest non-verbal avea conotaţii taumaturgice sau de protecţie a comunităţii, iar cel mai cunoscut exemplu reprezintă cercetarea auspiciilor. Această acomodare mutuală dintre diferitele activităţi încorporate în cadrul unei culturi, la care participă în mod concret şi indisolubil dimensiunea religioasă şi cea economică, atinge viaţa atât la nivel exterior, cât şi subliminal. Părinţii marketingului au conştientizat această forţă a simbolurilor non-verbale de natură mitologică, sacră şi culturală şi doresc o exploatare a lor. În studiul de faţă vom descoperi particularităţile sistemului simbolurilor sacre şi ale celor contemporane. Unul dintre sistemele simbolice analizate în cele ce urmează este mărul (Apple, simbol al căderii omului din starea paradisiacă.SYMBOLIC SYSTEM – EDUCATIONAL VALUETraditional History reveals a series of cave paintings, hieroglyphs and sacred texts which unveil a series of expression of everyday life. Around them people organized the life, they were making a level of hope, bring into life educational, spiritual and social values. A certain gesture non-verbal have thaumaturgy connotations or the protection of the com­munity and the most known example are augurs. This mutual respect between the various activities incorporated within a culture, in which are involved in a concrete manner and inextricably mixed up with the size of the religious and the economic, reaches the life at both outside and subliminally. Marketing parents have become aware of this force of symbols non-verbal nature of the mythology, sacred and cultural and have wanted an exploitation rights of their own. In

Simulation of irradiation X in human hand

International Nuclear Information System (INIS)

Amaya Falcon, F.

2001-01-01

Use of the Monte Carlo code MCNP to simulate a human hand irradiation with radiation X of radio diagnosis energy, in order to find the best range of energy to obtain a radiography with the smallest dose and the biggest contrast [es

New developments in simulating X-ray phase contrast imaging

International Nuclear Information System (INIS)

Peterzol, A.; Berthier, J.; Duvauchelle, P.; Babot, D.; Ferrero, C.

2007-01-01

A deterministic algorithm simulating phase contrast (PC) x-ray images for complex 3- dimensional (3D) objects is presented. This algorithm has been implemented in a simulation code named VXI (Virtual X-ray Imaging). The physical model chosen to account for PC technique is based on the Fresnel-Kirchhoff diffraction theory. The algorithm consists mainly of two parts. The first one exploits the VXI ray-tracing approach to compute the object transmission function. The second part simulates the PC image due to the wave front distortion introduced by the sample. In the first part, the use of computer-aided drawing (CAD) models enables simulations to be carried out with complex 3D objects. Differently from the VXI original version, which makes use of an object description via triangular facets, the new code requires a more 'sophisticated' object representation based on Non-Uniform Rational B-Splines (NURBS). As a first step we produce a spatial high resolution image by using a point and monochromatic source and an ideal detector. To simulate the polychromatic case, the intensity image is integrated over the considered x-ray energy spectrum. Then, in order to account for the system spatial resolution properties, the high spatial resolution image (mono or polychromatic) is convolved with the total point spread function of the imaging system under consideration. The results supplied by the presented algorithm are examined with the help of some relevant examples. (authors)

Fast scattering simulation tool for multi-energy x-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Sossin, A., E-mail: artur.sossin@cea.fr [CEA-LETI MINATEC Grenoble, F-38054 Grenoble (France); Tabary, J.; Rebuffel, V. [CEA-LETI MINATEC Grenoble, F-38054 Grenoble (France); Létang, J.M.; Freud, N. [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard (France); Verger, L. [CEA-LETI MINATEC Grenoble, F-38054 Grenoble (France)

2015-12-01

A combination of Monte Carlo (MC) and deterministic approaches was employed as a means of creating a simulation tool capable of providing energy resolved x-ray primary and scatter images within a reasonable time interval. Libraries of Sindbad, a previously developed x-ray simulation software, were used in the development. The scatter simulation capabilities of the tool were validated through simulation with the aid of GATE and through experimentation by using a spectrometric CdTe detector. A simple cylindrical phantom with cavities and an aluminum insert was used. Cross-validation with GATE showed good agreement with a global spatial error of 1.5% and a maximum scatter spectrum error of around 6%. Experimental validation also supported the accuracy of the simulations obtained from the developed software with a global spatial error of 1.8% and a maximum error of around 8.5% in the scatter spectra.

X-ray detection with Micromegas with background levels below 10$^{-6}$ keV$^{-1}$cm$^{-2}$s$^{-1}$

CERN Document Server

Aune, S; Calvet, D.; Dafni, T.; Diago, A.; Druillole, F.; Fanourakis, G.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Gardikiotis, A.; Garza, J.G.; Geralis, T.; Giomataris, I.; Gómez, H.; González-Díaz, D.; Herrera, D.C.; Iguaz, F.J.; Irastorza, I.G.; Jourde, D.; Luzón, G.; Mirallas, H.; Mols, J.P.; Papaevangelou, T.; Rodríguez, A.; Seguí, L.; Tomás, A.; Vafeiadis, T.; Yildiz, S.C.

2013-01-01

Micromegas detectors are an optimum technological choice for the detection of low energy x-rays. The low background techniques applied to these detectors yielded remarkable background reductions over the years, being the CAST experiment beneficiary of these developments. In this document we report on the latest upgrades towards further background reductions and better understanding of the detectors' response. The upgrades encompass the readout electronics, a new detector design and the implementation of a more efficient cosmic muon veto system. Background levels below 10$^{-6}$keV$^{-1}$cm$^{-2}$s$^{-1}$ have been obtained at sea level for the first time, demonstrating the feasibility of the expectations posed by IAXO, the next generation axion helioscope. Some results obtained with a set of measurements conducted in the x-ray beam of the CAST Detector Laboratory will be also presented and discussed.

Characterization, propagation, and simulation of sources and backgrounds; Proceedings of the Meeting, Orlando, FL, Apr. 2, 3, 1991

Science.gov (United States)

Watkins, Wendell R.; Clement, Dieter

The present conference discusses the design of IR imaging radiometers, IR clutter measurements of marine backgrounds, a global evaluation of thermal IR countermeasures, the estimation of scene-correlation lengths, the dimension and lacunarity measurement of IR images using Hilbert scanning, modeling the time-dependent obscuration in simulated imaging of dust and smoke clouds, and the thermal and radiometric modeling of terrain backgrounds. Also discussed are the simulation of partially obscured scenes using the 'radiosity' method, dynamic sea-image generation, atmospheric propagation effects on pattern recognition by neural networks, a thermal model for real-time textured IR background simulation, and interferometric measurements of a high velocity mixing/shear layer. (No individual items are abstracted in this volume)

Computer simulation tools for X-ray analysis scattering and diffraction methods

CERN Document Server

Morelhão, Sérgio Luiz

2016-01-01

The main goal of this book is to break down the huge barrier of difficulties faced by beginners from many fields (Engineering, Physics, Chemistry, Biology, Medicine, Material Science, etc.) in using X-rays as an analytical tool in their research. Besides fundamental concepts, MatLab routines are provided, showing how to test and implement the concepts. The major difficult in analyzing materials by X-ray techniques is that it strongly depends on simulation software. This book teaches the users on how to construct a library of routines to simulate scattering and diffraction by almost any kind of samples. It provides to a young student the knowledge that would take more than 20 years to acquire by working on X-rays and relying on the available textbooks. In this book, fundamental concepts in applied X-ray physics are demonstrated through available computer simulation tools. Using MatLab, more than eighty routines are developed for solving the proposed exercises, most of which can be directly used in experimental...

„La Movida Madrilena” kā brīvības simbols 80. gadu Spānijā

OpenAIRE

Jesajana, Elmīra

2013-01-01

Bakalaura darbā tiek pētīts “Movida Madrileña” fenomens un tā ietekme uz sociokulturālajām izmaiņām Spānijā 20.gs. 80. gados. Tā mērķis ir analizēt “Movida Madrileña” kustību kā brīvības izpausmes veidu Spānijā 20.gs. 80. gados. Darbu veido trīs daļas. Teorētiskajā daļā tiek skaidroti tādi abstrakti jēdzieni kā brīvība un simbols. Praktiskajā daļā tiek pielietota Hannas Arendas brīvības teorija, lai izpētītu “Movida Madrileña” kustības izcelsmi un analizētu tās nozīmi sabiedrībā. Darb...

Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)

Energy Technology Data Exchange (ETDEWEB)

Lim, H.W.; Lee, H.W. [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Cho, H.S., E-mail: hscho1@yonsei.ac.kr [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Je, U.K.; Park, C.K.; Kim, K.S.; Kim, G.A.; Park, S.Y.; Lee, D.Y.; Park, Y.O.; Woo, T.H. [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Lee, S.H.; Chung, W.H.; Kim, J.W.; Kim, J.G. [R& D Center, JPI Healthcare Co., Ltd., Ansan 425-833 (Korea, Republic of)

2017-04-01

Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system. - Highlights: • It is proposed for the single grid-based phase-contrast x-ray imaging (g-PCXI) technique. • We implemented for a numerical simulation code. • The preliminary experiment with several samples to compare is performed. • It is expected to be useful to design an optimal g-PCXI system.

Monte Carlo simulation for background study of geophysical inspection with cosmic-ray muons

Science.gov (United States)

Nishiyama, Ryuichi; Taketa, Akimichi; Miyamoto, Seigo; Kasahara, Katsuaki

2016-08-01

Several attempts have been made to obtain a radiographic image inside volcanoes using cosmic-ray muons (muography). Muography is expected to resolve highly heterogeneous density profiles near the surface of volcanoes. However, several prior works have failed to make clear observations due to contamination by background noise. The background contamination leads to an overestimation of the muon flux and consequently a significant underestimation of the density in the target mountains. To investigate the origin of the background noise, we performed a Monte Carlo simulation. The main components of the background noise in muography are found to be low-energy protons, electrons and muons in case of detectors without particle identification and with energy thresholds below 1 GeV. This result was confirmed by comparisons with actual observations of nuclear emulsions. This result will be useful for detector design in future works, and in addition some previous works of muography should be reviewed from the view point of background contamination.

Pixel detectors for x-ray imaging spectroscopy in space

International Nuclear Information System (INIS)

Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L

2009-01-01

Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

Pixel detectors for x-ray imaging spectroscopy in space

Energy Technology Data Exchange (ETDEWEB)

Treis, J; Andritschke, R; Hartmann, R; Herrmann, S; Holl, P; Lauf, T; Lechner, P; Lutz, G; Meidinger, N; Porro, M; Richter, R H; Schopper, F; Soltau, H; Strueder, L [MPI Semiconductor Laboratory, Otto-Hahn-Ring 6, D-81739 Munich (Germany)], E-mail: jft@hll.mpg.de

2009-03-15

Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 x 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

Hyperspectral imaging simulation of object under sea-sky background

Science.gov (United States)

Wang, Biao; Lin, Jia-xuan; Gao, Wei; Yue, Hui

2016-10-01

Remote sensing image simulation plays an important role in spaceborne/airborne load demonstration and algorithm development. Hyperspectral imaging is valuable in marine monitoring, search and rescue. On the demand of spectral imaging of objects under the complex sea scene, physics based simulation method of spectral image of object under sea scene is proposed. On the development of an imaging simulation model considering object, background, atmosphere conditions, sensor, it is able to examine the influence of wind speed, atmosphere conditions and other environment factors change on spectral image quality under complex sea scene. Firstly, the sea scattering model is established based on the Philips sea spectral model, the rough surface scattering theory and the water volume scattering characteristics. The measured bi directional reflectance distribution function (BRDF) data of objects is fit to the statistical model. MODTRAN software is used to obtain solar illumination on the sea, sky brightness, the atmosphere transmittance from sea to sensor and atmosphere backscattered radiance, and Monte Carlo ray tracing method is used to calculate the sea surface object composite scattering and spectral image. Finally, the object spectrum is acquired by the space transformation, radiation degradation and adding the noise. The model connects the spectrum image with the environmental parameters, the object parameters, and the sensor parameters, which provide a tool for the load demonstration and algorithm development.

New technology and techniques for x-ray mirror calibration at PANTER

Science.gov (United States)

Freyberg, Michael J.; Budau, Bernd; Burkert, Wolfgang; Friedrich, Peter; Hartner, Gisela; Misaki, Kazutami; Mühlegger, Martin

2008-07-01

The PANTER X-ray Test Facility has been utilized successfully for developing and calibrating X-ray astronomical instrumentation for observatories such as ROSAT, Chandra, XMM-Newton, Swift, etc. Future missions like eROSITA, SIMBOL-X, or XEUS require improved spatial resolution and broader energy band pass, both for optics and for cameras. Calibration campaigns at PANTER have made use of flight spare instrumentation for space applications; here we report on a new dedicated CCD camera for on-ground calibration, called TRoPIC. As the CCD is similar to ones used for eROSITA (pn-type, back-illuminated, 75 μm pixel size, frame store mode, 450 μm micron wafer thickness, etc.) it can serve as prototype for eROSITA camera development. New techniques enable and enhance the analysis of measurements of eROSITA shells or silicon pore optics. Specifically, we show how sub-pixel resolution can be utilized to improve spatial resolution and subsequently the characterization of of mirror shell quality and of point spread function parameters in particular, also relevant for position reconstruction of astronomical sources in orbit.

Pixel detectors for x-ray imaging spectroscopy in space

Science.gov (United States)

Treis, J.; Andritschke, R.; Hartmann, R.; Herrmann, S.; Holl, P.; Lauf, T.; Lechner, P.; Lutz, G.; Meidinger, N.; Porro, M.; Richter, R. H.; Schopper, F.; Soltau, H.; Strüder, L.

2009-03-01

Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 × 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

Chandra and the VLT Jointly Investigate the Cosmic X-Ray Background

Science.gov (United States)

2001-03-01

Summary Important scientific advances often happen when complementary investigational techniques are brought together . In the present case, X-ray and optical/infrared observations with some of the world's foremost telescopes have provided the crucial information needed to solve a 40-year old cosmological riddle. Very detailed observations of a small field in the southern sky have recently been carried out, with the space-based NASA Chandra X-Ray Observatory as well as with several ground-based ESO telescopes, including the Very Large Telescope (VLT) at the Paranal Observatory (Chile). Together, they have provided the "deepest" combined view at X-ray and visual/infrared wavelengths ever obtained into the distant Universe. The concerted observational effort has already yielded significant scientific results. This is primarily due to the possibility to 'identify' most of the X-ray emitting objects detected by the Chandra X-ray Observatory on ground-based optical/infrared images and then to determine their nature and distance by means of detailed (spectral) observations with the VLT . In particular, there is now little doubt that the so-called 'X-ray background' , a seemingly diffuse short-wave radiation first detected in 1962, in fact originates in a vast number of powerful black holes residing in active nuclei of distant galaxies . Moreover, the present investigation has permitted to identify and study in some detail a prime example of a hitherto little known type of object, a distant, so-called 'Type II Quasar' , in which the central black hole is deeply embedded in surrounding gas and dust. These achievements are just the beginning of a most fruitful collaboration between "space" and "ground". It is yet another impressive demonstration of the rapid progress of modern astrophysics, due to the recent emergence of a new generation of extremely powerful instruments. PR Photo 09a/01 : Images of a small part of the Chandra Deep Field South , obtained with ESO telescopes

Diagnostic x-ray dosimetry using Monte Carlo simulation

International Nuclear Information System (INIS)

Ioppolo, J.L.; Tuchyna, T.; Price, R.I.; Buckley, C.E.

2002-01-01

An Electron Gamma Shower version 4 (EGS4) based user code was developed to simulate the absorbed dose in humans during routine diagnostic radiological procedures. Measurements of absorbed dose using thermoluminescent dosimeters (TLDs) were compared directly with EGS4 simulations of absorbed dose in homogeneous, heterogeneous and anthropomorphic phantoms. Realistic voxel-based models characterizing the geometry of the phantoms were used as input to the EGS4 code. The voxel geometry of the anthropomorphic Rando phantom was derived from a CT scan of Rando. The 100 kVp diagnostic energy x-ray spectra of the apparatus used to irradiate the phantoms were measured, and provided as input to the EGS4 code. The TLDs were placed at evenly spaced points symmetrically about the central beam axis, which was perpendicular to the cathode-anode x-ray axis at a number of depths. The TLD measurements in the homogeneous and heterogenous phantoms were on average within 7% of the values calculated by EGS4. Estimates of effective dose with errors less than 10% required fewer numbers of photon histories (1x10 7 ) than required for the calculation of dose profiles (1x10 9 ). The EGS4 code was able to satisfactorily predict and thereby provide an instrument for reducing patient and staff effective dose imparted during radiological investigations. (author)

Influence of plasma background including neutrals on scrape-off layer filaments using 3D simulations

Directory of Open Access Journals (Sweden)

D. Schwörer

2017-08-01

Full Text Available This paper investigates the effect of the plasma background, including neutrals in a self-consistent way, on filaments in the scrape-off layer (SOL of fusion devices. A strong dependency of filament motion on background density and temperature is observed. The radial filament motion shows an increase in velocity with decreasing background density and increasing background temperature. In the simulations presented here, three neutral-filament interaction models have been compared, one with a static neutral background, one with no interaction between filaments and neutrals, and one co-evolving the neutrals self consistently with the filaments. With the background conditions employed here, which do not show detachment, there are no significant effects of neutrals on filaments, as by the time the filament reaches maximum velocity, the neutral density has not changed significantly.

Simulation of pulse height analysis soft X-ray spectra expected from W7-X

Science.gov (United States)

Jabłoński, S.; Czarnecka, A.; Kubkowska, M.; Ryć, L.; Weller, A.; Biedermann, C.; König, R.; W7-X Team

2015-10-01

A computer code named RayX has been developed for checking the performance of a spectroscopy system and optimizing individual parts, like detectors and filters for the pulse height analysis (PHA) diagnostic system designed for the stellarator W7-X. Using the code, the intensity and shape of the X-ray spectra are simulated for different plasma scenarios characterized by varying the temperature and density profiles as well as the electron cyclotron resonance heating (ECRH) power over a wide range. In the simulations of the recorded spectra, the influence of geometrical configuration changes of the diagnostic system (pinhole size, detector size, location of each diagnostic component), of the timing of data collection, as well as of the type and thickness of filters are being investigated. The atomic processes of free-free (bremsstrahlung), free-bound (recombination radiation), and bound-bound emission (line radiation) are considered. For the impurities fractional abundancies of 3% carbon (C), 0.5% oxygen (O) and 0.002% iron (Fe) are taken into account. Information about the number of photons which reach the detector and the current generated inside the detector is given. It is shown that the distance between pinhole and detector has a larger impact on the registered spectra (intensity and total number of photons) than the distance between plasma and pinhole. Based on the results of the simulations, the expected optimal positions of the individual components (pinholes, detectors) were defined for the PHA W7-X diagnostic system. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

The X CO Conversion Factor from Galactic Multiphase ISM Simulations

Science.gov (United States)

Gong, Munan; Ostriker, Eve C.; Kim, Chang-Goo

2018-05-01

{CO}(J=1{--}0) line emission is a widely used observational tracer of molecular gas, rendering essential the X CO factor, which is applied to convert CO luminosity to {{{H}}}2 mass. We use numerical simulations to study how X CO depends on numerical resolution, non-steady-state chemistry, physical environment, and observational beam size. Our study employs 3D magnetohydrodynamics (MHD) simulations of galactic disks with solar neighborhood conditions, where star formation and the three-phase interstellar medium (ISM) are self-consistently regulated by gravity and stellar feedback. Synthetic CO maps are obtained by postprocessing the MHD simulations with chemistry and radiation transfer. We find that CO is only an approximate tracer of {{{H}}}2. On parsec scales, W CO is more fundamentally a measure of mass-weighted volume density, rather than {{{H}}}2 column density. Nevertheless, =(0.7{\\textstyle {--}}1.0)× {10}20 {{{cm}}}-2 {{{K}}}-1 {{{km}}}-1 {{s}}, which is consistent with observations and insensitive to the evolutionary ISM state or radiation field strength if steady-state chemistry is assumed. Due to non-steady-state chemistry, younger molecular clouds have slightly lower and flatter profiles of X CO versus extinction than older ones. The {CO}-dark {{{H}}}2 fraction is 26%–79%, anticorrelated with the average extinction. As the observational beam size increases from 1 to 100 pc, increases by a factor of ∼2. Under solar neighborhood conditions, in molecular clouds is converged at a numerical resolution of 2 pc. However, the total CO abundance and luminosity are not converged even at the numerical resolution of 1 pc. Our simulations successfully reproduce the observed variations of X CO on parsec scales, as well as the dependence of X CO on extinction and the CO excitation temperature.

Magnetic vacancies; simulations and TDPAD experiments with 19 F in Al(x) Fe(1-x)

International Nuclear Information System (INIS)

Ekwall, B.; Johansson, K.; Lidbjoerk, P.; Lindgren, B.; Norlin, L.O.

1984-04-01

Al(x) Fe(1-x) alloys with less or equal 4.2 at percent have been studied by the TDPAD method utilising 19 F as probe. The hyperfine field was found to increase with 0.39(6) percent per at percent Al. A Monte Carlo simulation of the dipolar distribution, due to the missing Fe moments, agrees well with the experimental results.(author)

Simulation of X-ray irradiation on human hand

International Nuclear Information System (INIS)

Amaya, Fabiola; Montoya, Modesto

2001-01-01

Using the Monte Carlo code MCNP we simulate a human hand X-rays irradiation with radiodiagnostic energies to find the better range energy to make radiographs with the lowest dose and an optimal contrast. We calculate bone doses by considering a soft tissue - water - and calcium bone hand, which is irradiated with a million of X-rays photons from a punctual source. These photons are directed inside a conic angle on the hand. Afterwards, we simulate elements which normally compose bones (C, H, O, N, Mg, P, Ca, and S). We estimate bone dose considering: a) bone material (water, calcium and bone tissue); b) bone thickness (0.01; 0.1; 0.5; 1.0; 1.5 and 3.0 cm); and c) source-hand distance (30, 50, 70 and 90 cm). We calculate photon transmission percent through soft tissue and bone tissue and the statistics from the number of photons that reach the radiographic film after passing through soft tissue or bone tissue for our geometric configuration. We found that we can obtain a good image contrast by using X-rays with energies in the range of 20 to 40 keV. (author)

Dosimetric comparison between CT and X-ray simulation of radiotherapy for lung cancer

International Nuclear Information System (INIS)

Kali Ayguli, Zhang Jinrong; Wang Juwu; Ge Feng; Wang Haifeng; Xu Suling

2007-01-01

Objective: To compare radiotherapy plan of conventional X-ray simulation with CT simulation by 3D-TPS for lung cancer. Methods: Thirty-three patients were allotted to receive both conventional X-ray simulation and CT simulation in the same treatment position. 3D-TPS was used to design 4-field conventional plan of X-ray simulation (RT), 4-field two dimensional plan(2D)and three dimensional conformal radiation plan(3DCRT) of CT simulation for all patients. The total dose was 50 Gy. Dose volume histogram(DVH) was applied to evaluate the difference of target coverage, dose distribution and normal tissue protection among the three plans. Results: 3DCRT and 2D based on CT simulation were superior to RT in the target coverage, target conformity index (TCI) and target homogeneity (TH) (P 20 , V 30 and mean lung dose were similar among 3DCRT, 2D and RT plans. Moreover, the maximum doses of spinal cord were significantly different among the three plans. No statistical differences of doses to 30% of the heart and esophagus volume among the three plans were observed. Conclusions: There is significantly better tumour volume coverage in CT simulation when compared with X-ray conventional simulation. Target volume delineation by CT simulation is improved significantly. The dose distribution is improved by using three dimensional treatment planning system. 3DCRT plan is superior to 2D plans in target conformity index and target homogeneity. Doses delivered to organs surrounding the target such as lung and heart were reduced significantly in 3DCRT. (authors)

Simulations of multi-contrast x-ray imaging using near-field speckles

Energy Technology Data Exchange (ETDEWEB)

Zdora, Marie-Christine [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom and Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Herzen, Julia; Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany)

2016-01-28

X-ray dark-field and phase-contrast imaging using near-field speckles is a novel technique that overcomes limitations inherent in conventional absorption x-ray imaging, i.e. poor contrast for features with similar density. Speckle-based imaging yields a wealth of information with a simple setup tolerant to polychromatic and divergent beams, and simple data acquisition and analysis procedures. Here, we present a simulation software used to model the image formation with the speckle-based technique, and we compare simulated results on a phantom sample with experimental synchrotron data. Thorough simulation of a speckle-based imaging experiment will help for better understanding and optimising the technique itself.

Voxel-based Monte Carlo simulation of X-ray imaging and spectroscopy experiments

International Nuclear Information System (INIS)

Bottigli, U.; Brunetti, A.; Golosio, B.; Oliva, P.; Stumbo, S.; Vincze, L.; Randaccio, P.; Bleuet, P.; Simionovici, A.; Somogyi, A.

2004-01-01

A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogeneous samples is presented. The energy spectrum, polarization and profile of the incident beam can be defined so that X-ray tube systems as well as synchrotron sources can be simulated. The sample is modeled as a 3D regular grid. The chemical composition and density is given at each point of the grid. Photoelectric absorption, fluorescent emission, elastic and inelastic scattering are included in the simulation. The core of the simulation is a fast routine for the calculation of the path lengths of the photon trajectory intersections with the grid voxels. The voxel representation is particularly useful for samples that cannot be well described by a small set of polyhedra. This is the case of most naturally occurring samples. In such cases, voxel-based simulations are much less expensive in terms of computational cost than simulations on a polygonal representation. The efficient scheme used for calculating the path lengths in the voxels and the use of variance reduction techniques make the code suitable for the detailed simulation of complex experiments on generic samples in a relatively short time. Examples of applications to X-ray imaging and spectroscopy experiments are discussed

Voxel-based Monte Carlo simulation of X-ray imaging and spectroscopy experiments

Energy Technology Data Exchange (ETDEWEB)

Bottigli, U. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Sezione INFN di Cagliari (Italy); Brunetti, A. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Golosio, B. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy) and Sezione INFN di Cagliari (Italy)]. E-mail: golosio@uniss.it; Oliva, P. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Stumbo, S. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Vincze, L. [Department of Chemistry, University of Antwerp (Belgium); Randaccio, P. [Dipartimento di Fisica dell' Universita di Cagliari and Sezione INFN di Cagliari (Italy); Bleuet, P. [European Synchrotron Radiation Facility, Grenoble (France); Simionovici, A. [European Synchrotron Radiation Facility, Grenoble (France); Somogyi, A. [European Synchrotron Radiation Facility, Grenoble (France)

2004-10-08

A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogeneous samples is presented. The energy spectrum, polarization and profile of the incident beam can be defined so that X-ray tube systems as well as synchrotron sources can be simulated. The sample is modeled as a 3D regular grid. The chemical composition and density is given at each point of the grid. Photoelectric absorption, fluorescent emission, elastic and inelastic scattering are included in the simulation. The core of the simulation is a fast routine for the calculation of the path lengths of the photon trajectory intersections with the grid voxels. The voxel representation is particularly useful for samples that cannot be well described by a small set of polyhedra. This is the case of most naturally occurring samples. In such cases, voxel-based simulations are much less expensive in terms of computational cost than simulations on a polygonal representation. The efficient scheme used for calculating the path lengths in the voxels and the use of variance reduction techniques make the code suitable for the detailed simulation of complex experiments on generic samples in a relatively short time. Examples of applications to X-ray imaging and spectroscopy experiments are discussed.

Numerical simulation of the SLAC X-100 klystron using RKTW2D

International Nuclear Information System (INIS)

Ryne, R.D.; Vlieks, A.E.

1991-05-01

We have performed numerical simulations of the X-100 klystron being developed at Stanford Linear Accelerator Center. The X-100 is being developed as a possible source for the next generation of linear collider, and will be required to produce ∼100 MW of power for a duration of ∼800 ns. Our simulations were performed using the simulation programs RKTW1D and RKTW2D, developed at Lawrence Livermore National Laboratory. The codes were used to investigate the operation of the klystron over a wide range of operating conditions. We will present comparisons of the simulation results with experimental results. 3 refs., 5 figs

Multilayer on-chip stacked Fresnel zone plates: Hard x-ray fabrication and soft x-ray simulations

Energy Technology Data Exchange (ETDEWEB)

Li, Kenan; Wojcik, Michael J.; Ocola, Leonidas E.; Divan, Ralu; Jacobsen, Chris

2015-11-01

Fresnel zone plates are widely used as x-ray nanofocusing optics. To achieve high spatial resolution combined with good focusing efficiency, high aspect ratio nanolithography is required, and one way to achieve that is through multiple e-beam lithography writing steps to achieve on-chip stacking. A two-step writing process producing 50 nm finest zone width at a zone thickness of 1.14 µm for possible hard x-ray applications is shown here. The authors also consider in simulations the case of soft x-ray focusing where the zone thickness might exceed the depth of focus. In this case, the authors compare on-chip stacking with, and without, adjustment of zone positions and show that the offset zones lead to improved focusing efficiency. The simulations were carried out using a multislice propagation method employing Hankel transforms.

Simulation of X-ray signals

International Nuclear Information System (INIS)

Weller, A.

1980-12-01

A parameterized form of the local emissivity is used for the simulation of soft X-ray signals obtained on the WENDELSTEIN W VII-A stellarator with a 30 diode array. Numerical calculation of the line integrals for the different viewing angles and for a set of rotation angles covering one full signal period provides simulated periodic signals. In addition radial profiles of the line integrated emmission averaged over some time interval or at specific times, the relative amplitude modulation and the relative phase of the oscillations are calculated. These have to be fitted to the corresponding measured signals and profiles in order to get a reliable picture of the local emissivity. The model can take into account two poloidally asymmetric contributions of the type m = 1,2,3 or 4 (m = poloidal mode number). Each asymmetry can be generated in two ways (modulation of intensity and of geometry parameters). Besides an uniform rotation of the asymmetric terms some specific simple time evolution of the signals can be included (non-uniform rotation, growth of oscillations, sawtooth oscillations). The various input parameters are illustrated and the result of a simulation procedure is presented for a particular discharge in W VII-A. (orig.)

The Contribution of Compton-Thick AGN/ULIRGs to the X-Ray Background

Science.gov (United States)

Nardini, Emanuele

Accretion onto the supermassive black holes located at the centre of Active Galactic Nuclei(AGN) is one of the most efficient power sources in the Universe, and provides a significant contribution to the energy radiated over cosmic times. The spectral shape of the X-ray background and its progressive resolution strongly suggests that most AGN are heavily obscured by large amounts of dust and gas. Their primary radiation field is reprocessed and re-emitted at longer wavelengths, driving a huge IR luminosity. Ultraluminous Infrared Galaxies (ULIRGs) are the local counterparts of the high-redshift (z sport the typical features of buried AGN in the mid-IR. IRAS 12127 1412 was observed for the first time in the X-rays by our group. Its Chandra spectrum clearly shows the signatures of AGN reflection at 2 10 keV. Similar properties were previously found in IRAS 00182 7112. Our Suzaku observations will allow to pinpont the AGN emission above 10 keV, and will provide fundamental information on the physical and geometrical structure of Compton-thick AGN embedded in a nuclear starburst. These sources are believed to experience the very initial phase of the AGN feedback on the surrounding environment, eventually leading to the formation of powerful optically- bright quasars. Besides this, we stress another remarkable opportunity related to the study of these two ULIRGs. Due to their really unique mid-IR and hard X-ray spectral properties, IRAS 00182 7112 and IRAS 12127 1412 can be considered as representative templates for a significant fraction of the obscured AGN population. Their broadband spectral energy distribution can then be used to calibrate new photometric diagnostics based on mid-IR colors and bolometric corrections, capable of selecting their faint counterparts within the IR deep fields. The wealth of data in the WISE and Spitzer archives will allow a complete census of this AGN subclass. The reflection efficiency inferred from our new Suzaku observations will make

A Pipelining Implementation for Parsing X-ray Diffraction Source Data and Removing the Background Noise

International Nuclear Information System (INIS)

Bauer, Michael A; Biem, Alain; McIntyre, Stewart; Xie Yuzhen

2010-01-01

Synchrotrons can be used to generate X-rays in order to probe materials at the atomic level. One approach is to use X-ray diffraction (XRD) to do this. The data from an XRD experiment consists of a sequence of digital image files which for a single scan could consist of hundreds or even thousands of digital images. Existing analysis software processes these images individually sequentially and is usually used after the experiment is completed. The results from an XRD detector can be thought of as a sequence of images, generated during the scan by the X-ray beam. If these images could be analyzed in near real-time, the results could be sent to the researcher running the experiment and used to improve the overall experimental process and results. In this paper, we report on a stream processing application to remove background from XRD images using a pipelining implementation. We describe our implementation techniques of using IBM Infosphere Streams for parsing XRD source data and removing the background. We present experimental results showing the super-linear speedup attained over a purely sequential version of the algorithm on a quad-core machine. These results demonstrate the potential of making good use of multi-cores for high-performance stream processing of XRD images.

The ISM From the Soft X-ray Background Perspective

Science.gov (United States)

Snowden, S. L.

2003-01-01

In the past few years progress in understanding the local and Galactic ISM in terms of the diffuse X-ray background has been as much about what hasn't been seen as it has been about detections. High resolution spectra of the local SXRB have been observed, but are inconsistent with current thermal emission models. An excess over the extrapolation of the high-energy (most clearly visible at E greater than 1.5 keV) extragalactic power law down to 3/4 keV has been observed but only at the level consistent with cosmological models, implying the absence of at least a bright hot Galactic halo. A very recent FUSE result indicates that O VI emission from the Local Hot Bubble is insignificant, if it exists at all, a result which is also inconsistent with current thermal emission models. A short review of the current status of our (well, at least my) understanding of the Galactic SXRB and ISM is presented here.

Real-Time Simulation of Aeroheating of the Hyper-X Airplane

Science.gov (United States)

Gong, Les

2005-01-01

A capability for real-time computational simulation of aeroheating has been developed in support of the Hyper-X program, which is directed toward demonstrating the feasibility of operating an air-breathing ramjet/scramjet engine at mach 5, mach 7, and mach 10. The simulation software will serve as a valuable design tool for initial trajectory studies in which aerodynamic heating is expected to exert a major influence in the design of the Hyper-X airplane; this tool will aid in the selection of materials, sizing of structural skin thicknesses, and selection of components of a thermal-protection system (TPS) for structures that must be insulated against aeroheating.

Advances in X-Ray Simulator Technology

Science.gov (United States)

1995-07-01

d’Etudes de Gramat ; I. Vitkovitsky, Logicon RDA INTRODUCTION DNA’s future x-ray simulators are based upon inductive energy storage, a technology which...switch. SYRINX, a proposed design to be built by the Centre d’Etudes de Gramat (CEG) in France would employ a modular approach, possibly with a...called SYRINX, would be built at the Centred’ Etudes de Gramat (CEG). It would employ a modular.long conduction time current source to drive a PRS

THE EFFECTS OF THE IONIZING RADIATION BACKGROUND ON GALAXY EVOLUTION

International Nuclear Information System (INIS)

Hambrick, D. Clay; Ostriker, Jeremiah P.; Naab, Thorsten; Johansson, Peter H.

2009-01-01

We find that the amount and nature of the assumed ionizing background can strongly affect galaxy formation and evolution. Galaxy evolution simulations typically incorporate an ultraviolet background which falls off rapidly above z = 3; e.g., that of Haardt and Madau. However, this decline may be too steep to fit the Wilkinson Microwave Anistropy Probe constraints on electron scattering optical depth or observations of intermediate redshift (z ∼ 2-4) Lyα forest transmission. As an alternative, we present simulations of the cosmological formation of individual galaxies with UV backgrounds that decline more slowly at high redshift: both a simple intensity rescaling and the background recently derived by Faucher-Giguere, which softens the spectrum at higher redshifts. We also test an approximation of the X-ray background with a similar z dependence. We find for the test galaxies that an increase in either the intensity or hardness of ionizing radiation generically pushes star formation toward lower redshifts: although overall star formation in the simulation boxes is reduced by 10%-25%, the galaxies show a factor of ∼2 increase in the fraction of stars within a 30 kpc radius that are formed after z = 1. Other effects include late gas inflows enhanced up to 30 times, stellar half-mass radii decreased by up to 30%, central velocity dispersions increased up to 40%, and a strong reduction in substructure. The magnitude of the effects depends on the environmental/accretion properties of the particular galaxy.

GEM gas detectors for soft X-ray imaging in fusion devices with neutron–gamma background

Energy Technology Data Exchange (ETDEWEB)

Pacella, Danilo, E-mail: danilo.pacella@enea.it [Associazione EURATOM-ENEA, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma (Italy); Romano, Afra; Gabellieri, Lori [Associazione EURATOM-ENEA, C.R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma (Italy); Murtas, Fabrizio [Istituto Nazionale di Fisica Nucleare, Via E. Fermi 45, 00044 Frascati, Roma (Italy); Mazon, Didier [Association EURATOM-CEA, CEA Cadarache, DSM/IRFM, 13108 St. Paul Lez Durance Cedex (France)

2013-08-21

A triple gas electron multiplier (GEM) detector has been built and characterized in a collaboration between ENEA, INFN and CEA to develop a soft X-ray imaging diagnostic for magnetic fusion plasmas. It has an active area of 5×5 cm{sup 2}, 128 pixels and electronics in counting mode. Since burning plasma experiments will have a very large background of radiation, this prototype has been tested with contemporary X-ray, neutron and gamma irradiation, to study the detection efficiencies, and the discrimination capabilities. The detector has been preliminarily characterized under DD neutron irradiation (2.45 MeV) up to 2.2×10{sup 6} n/s on the detector active area, showing a detection efficiency of about 10{sup −4}, while the detection efficiency of X-rays is more than three orders of magnitude higher. The detector has been also tested under DT neutron flux (14 MeV) up to 2.8×10{sup 8} n/s on the whole detector, with a detection efficiency of about 10{sup −5}. The calibration of the γ-rays detection has been done by means of a source of {sup 60}Co (gamma rays of energy 1.17 MeV and 1.33 MeV) and the detection efficiency was found of the order of 10{sup −4}. Thanks to the adjustable gain of the detector and the discrimination threshold of the electronics, it is possible to minimize the sensitivity to neutrons and gamma, and discriminate the X-ray signals even with very high radiative background.

Interactive X-ray and proton therapy training and simulation.

Science.gov (United States)

Hamza-Lup, Felix G; Farrar, Shane; Leon, Erik

2015-10-01

External beam X-ray therapy (XRT) and proton therapy (PT) are effective and widely accepted forms of treatment for many types of cancer. However, the procedures require extensive computerized planning. Current planning systems for both XRT and PT have insufficient visual aid to combine real patient data with the treatment device geometry to account for unforeseen collisions among system components and the patient. The 3D surface representation (S-rep) is a widely used scheme to create 3D models of physical objects. 3D S-reps have been successfully used in CAD/CAM and, in conjunction with texture mapping, in the modern gaming industry to customize avatars and improve the gaming realism and sense of presence. We are proposing a cost-effective method to extract patient-specific S-reps in real time and combine them with the treatment system geometry to provide a comprehensive simulation of the XRT/PT treatment room. The X3D standard is used to implement and deploy the simulator on the web, enabling its use not only for remote specialists' collaboration, simulation, and training, but also for patient education. An objective assessment of the accuracy of the S-reps obtained proves the potential of the simulator for clinical use.

Simulations of the muon-induced neutron background of the EDELWEISS-II experiment for Dark Matter search

International Nuclear Information System (INIS)

Horn, O.M.

2007-01-01

In modern astroparticle physics and cosmology, the nature of Dark Matter is one of the central problems. Particle Dark Matter in form of WIMPs is favoured among many proposed candidates. The EDELWEISS direct Dark Matter search uses Germanium bolometers to detect these particles by nuclear recoils. Here, the use of two signal channels on an event-by-event basis, namely the heat and ionisation signal, enables the detectors to discriminate between electron and nuclear recoils. This technique leaves neutrons in the underground laboratory as the main background for the experiment. Besides (α,n) reactions of natural radioactivity, neutrons are produced in electromagnetic and hadronic showers induced by cosmic ray muons in the surrounding rock and shielding material of the Germanium crystals. To reach high sensitivities, the EDELWEISS-II experiment, as well as other direct Dark Matter searches, has to efficiently suppress this neutron background. The present work is devoted to study the muon-induced neutron flux in the underground laboratory LSM and the interaction rate within the Germanium crystals by using the Monte Carlo simulation toolkit Geant4. To ensure reliable results, the implemented physics in the toolkit regarding neutron production is tested in a benchmark geometry and results are compared to experimental data and other simulation codes. Also, the specific energy and angular distribution of the muon flux in the underground laboratory as a consequence of the asymmetric mountain overburden is implemented. A good agreement of the simulated muon flux is shown in a comparison to preliminary experimental data obtained with the EDELWEISS-II muon veto system. Furthermore, within a detailed geometry of the experimental setup, the muon-induced background rate of nuclear recoils in the bolometers is simulated. Coincidences of recoil events in the Germanium with an energy deposit of the muoninduced shower in the plastic scintillators of the veto system are studied to

Simulations of the muon-induced neutron background of the EDELWEISS-II experiment for Dark Matter search

Energy Technology Data Exchange (ETDEWEB)

Horn, O M

2007-12-21

In modern astroparticle physics and cosmology, the nature of Dark Matter is one of the central problems. Particle Dark Matter in form of WIMPs is favoured among many proposed candidates. The EDELWEISS direct Dark Matter search uses Germanium bolometers to detect these particles by nuclear recoils. Here, the use of two signal channels on an event-by-event basis, namely the heat and ionisation signal, enables the detectors to discriminate between electron and nuclear recoils. This technique leaves neutrons in the underground laboratory as the main background for the experiment. Besides ({alpha},n) reactions of natural radioactivity, neutrons are produced in electromagnetic and hadronic showers induced by cosmic ray muons in the surrounding rock and shielding material of the Germanium crystals. To reach high sensitivities, the EDELWEISS-II experiment, as well as other direct Dark Matter searches, has to efficiently suppress this neutron background. The present work is devoted to study the muon-induced neutron flux in the underground laboratory LSM and the interaction rate within the Germanium crystals by using the Monte Carlo simulation toolkit Geant4. To ensure reliable results, the implemented physics in the toolkit regarding neutron production is tested in a benchmark geometry and results are compared to experimental data and other simulation codes. Also, the specific energy and angular distribution of the muon flux in the underground laboratory as a consequence of the asymmetric mountain overburden is implemented. A good agreement of the simulated muon flux is shown in a comparison to preliminary experimental data obtained with the EDELWEISS-II muon veto system. Furthermore, within a detailed geometry of the experimental setup, the muon-induced background rate of nuclear recoils in the bolometers is simulated. Coincidences of recoil events in the Germanium with an energy deposit of the muoninduced shower in the plastic scintillators of the veto system are studied

Simulating X-ray diffraction of textured films

DEFF Research Database (Denmark)

Breiby, Dag W.; Bunk, Oliver; Andreasen, Jens Wenzel

2008-01-01

Computationally efficient simulations of grazing-incidence X-ray diffraction (GIXD) are discussed, with particular attention given to textured thin polycrystalline films on supporting substrates. A computer program has been developed for simulating scattering from thin films exhibiting varying...... degrees of preferred orientation. One emphasized common case is that of a 'fibre' symmetry axis perpendicular to the sample plane, resulting from crystallites having one well defined crystal facet towards the substrate, but no preferred inplane orientation. Peak splitting caused by additional scattering......, the mathematically simplest possible descriptions are sought whenever feasible. The practical use of the program is demonstrated for a selected thin-film example, perylene, which is of relevance for organic electronics....

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants

International Nuclear Information System (INIS)

Vink, Jacco

2009-01-01

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and γ-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification.The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations.Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants

Science.gov (United States)

Vink, Jacco

2009-05-01

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and γ-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification. The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations. Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Soft X-ray excess in the Coma cluster from a Cosmic Axion Background

Energy Technology Data Exchange (ETDEWEB)

Angus, Stephen; Conlon, Joseph P.; Marsh, M.C. David; Powell, Andrew J.; Witkowski, Lukas T., E-mail: stephen.angus@physics.ox.ac.uk, E-mail: j.conlon1@physics.ox.ac.uk, E-mail: david.marsh1@physics.ox.ac.uk, E-mail: andrew.powell2@physics.ox.ac.uk, E-mail: l.witkowski@thphys.uni-heidelberg.de [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2014-09-01

We show that the soft X-ray excess in the Coma cluster can be explained by a cosmic background of relativistic axion-like particles (ALPs) converting into photons in the cluster magnetic field. We provide a detailed self-contained review of the cluster soft X-ray excess, the proposed astrophysical explanations and the problems they face, and explain how a 0.1- 1 keV axion background naturally arises at reheating in many string theory models of the early universe. We study the morphology of the soft excess by numerically propagating axions through stochastic, multi-scale magnetic field models that are consistent with observations of Faraday rotation measures from Coma. By comparing to ROSAT observations of the 0.2- 0.4 keV soft excess, we find that the overall excess luminosity is easily reproduced for g{sub aγγ} ∼ 2 × 10{sup -13} Ge {sup -1}. The resulting morphology is highly sensitive to the magnetic field power spectrum. For Gaussian magnetic field models, the observed soft excess morphology prefers magnetic field spectra with most power in coherence lengths on O(3 kpc) scales over those with most power on O(12 kpc) scales. Within this scenario, we bound the mean energy of the axion background to 50 eV∼< ( E{sub a} ) ∼< 250 eV, the axion mass to m{sub a} ∼< 10{sup -12} eV, and derive a lower bound on the axion-photon coupling g{sub aγγ} ∼> √(0.5/Δ N{sub eff}) 1.4 × 10{sup -13} Ge {sup -1}.

Soft X-ray excess in the Coma cluster from a Cosmic Axion Background

International Nuclear Information System (INIS)

Angus, Stephen; Conlon, Joseph P.; Marsh, M.C. David; Powell, Andrew J.; Witkowski, Lukas T.

2014-01-01

We show that the soft X-ray excess in the Coma cluster can be explained by a cosmic background of relativistic axion-like particles (ALPs) converting into photons in the cluster magnetic field. We provide a detailed self-contained review of the cluster soft X-ray excess, the proposed astrophysical explanations and the problems they face, and explain how a 0.1- 1 keV axion background naturally arises at reheating in many string theory models of the early universe. We study the morphology of the soft excess by numerically propagating axions through stochastic, multi-scale magnetic field models that are consistent with observations of Faraday rotation measures from Coma. By comparing to ROSAT observations of the 0.2- 0.4 keV soft excess, we find that the overall excess luminosity is easily reproduced for g aγγ  ∼ 2 × 10 -13  Ge -1 . The resulting morphology is highly sensitive to the magnetic field power spectrum. For Gaussian magnetic field models, the observed soft excess morphology prefers magnetic field spectra with most power in coherence lengths on O(3 kpc) scales over those with most power on O(12 kpc) scales. Within this scenario, we bound the mean energy of the axion background to 50 eV∼< ( E a  ) ∼< 250 eV, the axion mass to m a  ∼< 10 -12  eV, and derive a lower bound on the axion-photon coupling g aγγ  ∼> √(0.5/Δ N eff ) 1.4 × 10 -13  Ge -1

Simulating the x-ray image contrast to setup techniques with desired flaw detectability

Science.gov (United States)

Koshti, Ajay M.

2015-04-01

The paper provides simulation data of previous work by the author in developing a model for estimating detectability of crack-like flaws in radiography. The methodology is developed to help in implementation of NASA Special x-ray radiography qualification, but is generically applicable to radiography. The paper describes a method for characterizing the detector resolution. Applicability of ASTM E 2737 resolution requirements to the model are also discussed. The paper describes a model for simulating the detector resolution. A computer calculator application, discussed here, also performs predicted contrast and signal-to-noise ratio calculations. Results of various simulation runs in calculating x-ray flaw size parameter and image contrast for varying input parameters such as crack depth, crack width, part thickness, x-ray angle, part-to-detector distance, part-to-source distance, source sizes, and detector sensitivity and resolution are given as 3D surfaces. These results demonstrate effect of the input parameters on the flaw size parameter and the simulated image contrast of the crack. These simulations demonstrate utility of the flaw size parameter model in setting up x-ray techniques that provide desired flaw detectability in radiography. The method is applicable to film radiography, computed radiography, and digital radiography.

X-ray Studies of Unidentified Galactic TeV Gamma-ray Sources

Science.gov (United States)

Pühlhofer, Gerd

2009-05-01

Many of the recently discovered Galactic TeV sources remain unidentified to date. A large fraction of the sources is possibly associated with relic pulsar wind nebula (PWN) systems. One key question here is the maximum energy (beyond TeV) attained in the compact PWNe. Hard X-ray emission can trace those particles, but current non-focussing X-ray instruments above 10 keV have difficulties to deconvolve the hard pulsar spectrum from its surrounding nebula. Some of the new TeV sources are also expected to originate from middle-aged and possibly even from old supernova remnants (SNR). But no compelling case for such an identification has been found yet. In established young TeV-emitting SNRs, X-ray imaging above 10 keV could help to disentangle the leptonic from the hadronic emission component in the TeV shells, if secondary electrons produced in hadronic collisions can be effectively detected. As SNRs get older, the high energy electron component is expected to fade away. This may allow to verify the picture through X-ray spectral evolution of the source population. Starting from the lessons we have learned so far from X-ray follow-up observations of unidentified TeV sources, prospects for Simbol-X to resolve open questions in this field will be discussed.

X-ray Studies of Unidentified Galactic TeV Gamma-ray Sources

International Nuclear Information System (INIS)

Puehlhofer, Gerd

2009-01-01

Many of the recently discovered Galactic TeV sources remain unidentified to date. A large fraction of the sources is possibly associated with relic pulsar wind nebula (PWN) systems. One key question here is the maximum energy (beyond TeV) attained in the compact PWNe. Hard X-ray emission can trace those particles, but current non-focussing X-ray instruments above 10 keV have difficulties to deconvolve the hard pulsar spectrum from its surrounding nebula.Some of the new TeV sources are also expected to originate from middle-aged and possibly even from old supernova remnants (SNR). But no compelling case for such an identification has been found yet. In established young TeV-emitting SNRs, X-ray imaging above 10 keV could help to disentangle the leptonic from the hadronic emission component in the TeV shells, if secondary electrons produced in hadronic collisions can be effectively detected. As SNRs get older, the high energy electron component is expected to fade away. This may allow to verify the picture through X-ray spectral evolution of the source population.Starting from the lessons we have learned so far from X-ray follow-up observations of unidentified TeV sources, prospects for Simbol-X to resolve open questions in this field will be discussed.

Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

Energy Technology Data Exchange (ETDEWEB)

Beasley, D.G., E-mail: dgbeasley@itn.pt; Marques, A.C.; Alves, L.C.; Silva, R.C. da

2013-07-01

A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster.

Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

International Nuclear Information System (INIS)

Beasley, D.G.; Marques, A.C.; Alves, L.C.; Silva, R.C. da

2013-01-01

A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster

INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission

Science.gov (United States)

Türler, M.; Chernyakova, M.; Courvoisier, T. J.-L.; Lubiński, P.; Neronov, A.; Produit, N.; Walter, R.

2010-03-01

Aims: We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations in early 2006. Methods: We analyze the modulation of the IBIS/ISGRI detector counts induced by the passage of the Earth through the field of view of the instrument. Unlike previous studies, we do not fix the spectral shape of the various contributions, but model instead their spatial distribution and derive for each of them the expected modulation of the detector counts. The spectra of the diffuse emission components are obtained by fitting the normalizations of the model lightcurves to the observed modulation in different energy bins. Because of degeneracy, we guide the fits with a realistic choice of the input parameters and a constraint for spectral smoothness. Results: The obtained CXB spectrum is consistent with the historic HEAO-1 results and falls slightly below the spectrum derived with Swift/BAT. A 10% higher normalization of the CXB cannot be completely excluded, but it would imply an unrealistically high albedo of the Earth. The derived spectrum of the GRXE confirms the presence of a minimum around 80 keV with improved statistics and yields an estimate of ~0.6 M⊙ for the average mass of white dwarfs in the Galaxy. The analysis also provides updated normalizations for the spectra of the Earth's albedo and the cosmic-ray induced atmospheric emission. Conclusions: This study demonstrates the potential of INTEGRAL Earth-occultation observations to derive the hard X-ray spectra of three fundamental components: the CXB, the GRXE and the Earth emission. Further observations would be extremely valuable to confirm our results with improved statistics.

3D relativistic MHD numerical simulations of X-shaped radio sources

Science.gov (United States)

Rossi, P.; Bodo, G.; Capetti, A.; Massaglia, S.

2017-10-01

Context. A significant fraction of extended radio sources presents a peculiar X-shaped radio morphology: in addition to the classical double lobed structure, radio emission is also observed along a second axis of symmetry in the form of diffuse wings or tails. In a previous investigation we showed the existence of a connection between the radio morphology and the properties of the host galaxies. Motivated by this connection we performed two-dimensional numerical simulations showing that X-shaped radio sources may naturally form as a jet propagates along the major axis a highly elliptical density distribution, because of the fast expansion of the cocoon along the minor axis of the distribution. Aims: We intend to extend our analysis by performing three-dimensional numerical simulations and investigating the role of different parameters in determining the formation of the X-shaped morphology. Methods: The problem is addressed by numerical means, carrying out three-dimensional relativistic magnetohydrodynamic simulations of bidirectional jets propagating in a triaxial density distribution. Results: We show that only jets with power ≲ 1044 erg s-1 can give origin to an X-shaped morphology and that a misalignment of 30° between the jet axis and the major axis of the density distribution is still favourable to the formation of this kind of morphology. In addition we compute synthetic radio emission maps and polarization maps. Conclusions: In our scenario for the formation of X-shaped radio sources only low power FRII can give origin to such kind of morphology. Our synthetic emission maps show that the different observed morphologies of X-shaped sources can be the result of similar structures viewed under different perspectives.

Simulated cosmic microwave background maps at 0.5 deg resolution: Basic results

Science.gov (United States)

Hinshaw, G.; Bennett, C. L.; Kogut, A.

1995-01-01

We have simulated full-sky maps of the cosmic microwave background (CMB) anisotropy expected from cold dark matter (CDM) models at 0.5 deg and 1.0 deg angular resolution. Statistical properties of the maps are presented as a function of sky coverage, angular resolution, and instrument noise, and the implications of these results for observability of the Doppler peak are discussed. The rms fluctuations in a map are not a particularly robust probe of the existence of a Doppler peak; however, a full correlation analysis can provide reasonable sensitivity. We find that sensitivity to the Doppler peak depends primarily on the fraction of sky covered, and only secondarily on the angular resolution and noise level. Color plates of the simulated maps are presented to illustrate the anisotropies.

Observation of brightness profiles of the soft X-ray background in Gemini, Orion and Eridanus

International Nuclear Information System (INIS)

Zwijnenberg, E.

1976-01-01

The instrumentation and the measuring plan of a rocket flight experiment has been described, where the soft X-ray background (0.1-2.0 keV) of the sky near the galactic anti-center is measured. The equipment contains among other things an X-ray focussing instrument with high angular resolution and a large area detection system. Brightness profiles are taken from a number of objects among which are supernova remnants like the crab nebula and IC 443. The hot spot in Eridanus could be attributed to a supernova remnant with more than one shock front. Other objects seen are the Gemini enhancement and the Monoceros nebula

Computerized method for X-ray angular distribution simulation in radiological systems

International Nuclear Information System (INIS)

Marques, Marcio A.; Oliveira, Henrique J.Q. de; Frere, Annie F.; Schiabel, Homero; Marques, Paulo M.A.

1996-01-01

A method to simulate the changes in X-ray angular distribution (the Heel effect) for radiologic imaging systems is presented. This simulation method is described as to predict images for any exposure technique considering that the distribution is the cause of the intensity variation along the radiation field

GEANT4 simulation of the neutron background of the C$_6$D$_6$ set-up for capture studies at n_TOF

CERN Document Server

Žugec, P.; Bosnar, D.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Cortés, G.; Cortés-Giraldo, M.A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Duran, I.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A.R.; Giubrone, G.; Gómez-Hornillos, M.B.; Gonçalves, I.F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Heinitz, S.; Jenkins, D.G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Krtička, M.; Kroll, J.; Langer, C.; Lederer, C.; Leeb, H.; Leong, L.S.; Lo Meo, S.; Losito, R.; Manousos, A.; Marganiec, J.; Martìnez, T.; Massimi, C.; Mastinu, P.F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P.M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J.M.; Rauscher, T.; Reifarth, R.; Riego, A.; Roman, F.; Rubbia, C.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J.L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M.J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.

2014-05-09

The neutron sensitivity of the C$_6$D$_6$ detector setup used at n_TOF for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n_TOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a $^\\mathrm{nat}$C sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured $^\\mathrm{nat}$C yield has been discovered, which prevents the use of $^\\mathrm{nat}$C data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron backg...

Monte Carlo simulation of x-ray spectra in diagnostic radiology and mammography using MCNP4C

Energy Technology Data Exchange (ETDEWEB)

Ay, M R [Department of Physics and Nuclear Sciences, AmirKabir University of Technology, Tehran (Iran, Islamic Republic of); Shahriari, M [Department of Nuclear Engineering, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Sarkar, S [Department of Medical Physics, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Adib, M [TPP Co., GE Medical Systems, Iran Authorized Distributor, Tehran (Iran, Islamic Republic of); Zaidi, H [Division of Nuclear Medicine, Geneva University Hospital, 1211 Geneva (Switzerland)

2004-11-07

The general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) was used for the simulation of x-ray spectra in diagnostic radiology and mammography. The electrons were transported until they slow down and stop in the target. Both bremsstrahlung and characteristic x-ray production were considered in this work. We focus on the simulation of various target/filter combinations to investigate the effect of tube voltage, target material and filter thickness on x-ray spectra in the diagnostic radiology and mammography energy ranges. The simulated x-ray spectra were compared with experimental measurements and spectra calculated by IPEM report number 78. In addition, the anode heel effect and off-axis x-ray spectra were assessed for different anode angles and target materials and the results were compared with EGS4-based Monte Carlo simulations and measured data. Quantitative evaluation of the differences between our Monte Carlo simulated and comparison spectra was performed using student's t-test statistical analysis. Generally, there is a good agreement between the simulated x-ray and comparison spectra, although there are systematic differences between the simulated and reference spectra especially in the K-characteristic x-rays intensity. Nevertheless, no statistically significant differences have been observed between IPEM spectra and the simulated spectra. It has been shown that the difference between MCNP simulated spectra and IPEM spectra in the low energy range is the result of the overestimation of characteristic photons following the normalization procedure. The transmission curves produced by MCNP4C have good agreement with the IPEM report especially for tube voltages of 50 kV and 80 kV. The systematic discrepancy for higher tube voltages is the result of systematic differences between the corresponding spectra.

Monte Carlo simulation of x-ray spectra in diagnostic radiology and mammography using MCNP4C

Science.gov (United States)

Ay, M. R.; Shahriari, M.; Sarkar, S.; Adib, M.; Zaidi, H.

2004-11-01

The general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C) was used for the simulation of x-ray spectra in diagnostic radiology and mammography. The electrons were transported until they slow down and stop in the target. Both bremsstrahlung and characteristic x-ray production were considered in this work. We focus on the simulation of various target/filter combinations to investigate the effect of tube voltage, target material and filter thickness on x-ray spectra in the diagnostic radiology and mammography energy ranges. The simulated x-ray spectra were compared with experimental measurements and spectra calculated by IPEM report number 78. In addition, the anode heel effect and off-axis x-ray spectra were assessed for different anode angles and target materials and the results were compared with EGS4-based Monte Carlo simulations and measured data. Quantitative evaluation of the differences between our Monte Carlo simulated and comparison spectra was performed using student's t-test statistical analysis. Generally, there is a good agreement between the simulated x-ray and comparison spectra, although there are systematic differences between the simulated and reference spectra especially in the K-characteristic x-rays intensity. Nevertheless, no statistically significant differences have been observed between IPEM spectra and the simulated spectra. It has been shown that the difference between MCNP simulated spectra and IPEM spectra in the low energy range is the result of the overestimation of characteristic photons following the normalization procedure. The transmission curves produced by MCNP4C have good agreement with the IPEM report especially for tube voltages of 50 kV and 80 kV. The systematic discrepancy for higher tube voltages is the result of systematic differences between the corresponding spectra.

Background removal in X-ray fiber diffraction patterns

International Nuclear Information System (INIS)

Millane, R.P.; Arnott, S.

1985-01-01

Background can be a major source of error in measurement of diffracted intensities in fiber diffraction patterns. Errors can be large when poorly oriented less-crystalline specimens give diffraction patterns with little uncontaminated background. A method for estimating and removing a general global background in such cases is described and illustrated with an example. (orig.)

Partially coherent X-ray wavefront propagation simulations including grazing-incidence focusing optics.

Science.gov (United States)

Canestrari, Niccolo; Chubar, Oleg; Reininger, Ruben

2014-09-01

X-ray beamlines in modern synchrotron radiation sources make extensive use of grazing-incidence reflective optics, in particular Kirkpatrick-Baez elliptical mirror systems. These systems can focus the incoming X-rays down to nanometer-scale spot sizes while maintaining relatively large acceptance apertures and high flux in the focused radiation spots. In low-emittance storage rings and in free-electron lasers such systems are used with partially or even nearly fully coherent X-ray beams and often target diffraction-limited resolution. Therefore, their accurate simulation and modeling has to be performed within the framework of wave optics. Here the implementation and benchmarking of a wave-optics method for the simulation of grazing-incidence mirrors based on the local stationary-phase approximation or, in other words, the local propagation of the radiation electric field along geometrical rays, is described. The proposed method is CPU-efficient and fully compatible with the numerical methods of Fourier optics. It has been implemented in the Synchrotron Radiation Workshop (SRW) computer code and extensively tested against the geometrical ray-tracing code SHADOW. The test simulations have been performed for cases without and with diffraction at mirror apertures, including cases where the grazing-incidence mirrors can be hardly approximated by ideal lenses. Good agreement between the SRW and SHADOW simulation results is observed in the cases without diffraction. The differences between the simulation results obtained by the two codes in diffraction-dominated cases for illumination with fully or partially coherent radiation are analyzed and interpreted. The application of the new method for the simulation of wavefront propagation through a high-resolution X-ray microspectroscopy beamline at the National Synchrotron Light Source II (Brookhaven National Laboratory, USA) is demonstrated.

Monte Carlo simulation and gaussian broaden techniques for full energy peak of characteristic X-ray in EDXRF

International Nuclear Information System (INIS)

Li Zhe; Liu Min; Shi Rui; Wu Xuemei; Tuo Xianguo

2012-01-01

Background: Non-standard analysis (NSA) technique is one of the most important development directions of energy dispersive X-ray fluorescence (EDXRF). Purpose: This NSA technique is mainly based on Monte Carlo (MC) simulation and full energy peak broadening, which were studied preliminarily in this paper. Methods: A kind of MC model was established for Si-PIN based EDXRF setup, and the flux spectra were obtained for iron ore sample. Finally, the flux spectra were broadened by Gaussian broaden parameters calculated by a new method proposed in this paper, and the broadened spectra were compared with measured energy spectra. Results: MC method can be used to simulate EDXRF measurement, and can correct the matrix effects among elements automatically. Peak intensities can be obtained accurately by using the proposed Gaussian broaden technique. Conclusions: This study provided a key technique for EDXRF to achieve advanced NSA technology. (authors)

The Aouda.X space suit simulator and its applications to astrobiology.

Science.gov (United States)

Groemer, Gernot E; Hauth, Stefan; Luger, Ulrich; Bickert, Klaus; Sattler, Birgit; Hauth, Eva; Föger, Daniel; Schildhammer, Daniel; Agerer, Christian; Ragonig, Christoph; Sams, Sebastian; Kaineder, Felix; Knoflach, Martin

2012-02-01

We have developed the space suit simulator Aouda.X, which is capable of reproducing the physical and sensory limitations a flight-worthy suit would have on Mars. Based upon a Hard-Upper-Torso design, it has an advanced human-machine interface and a sensory network connected to an On-Board Data Handling system to increase the situational awareness in the field. Although the suit simulator is not pressurized, the physical forces that lead to a reduced working envelope and physical performance are reproduced with a calibrated exoskeleton. This allows us to simulate various pressure regimes from 0.3-1 bar. Aouda.X has been tested in several laboratory and field settings, including sterile sampling at 2800 m altitude inside a glacial ice cave and a cryochamber at -110°C, and subsurface tests in connection with geophysical instrumentation relevant to astrobiology, including ground-penetrating radar, geoacoustics, and drilling. The communication subsystem allows for a direct interaction with remote science teams via telemetry from a mission control center. Aouda.X as such is a versatile experimental platform for studying Mars exploration activities in a high-fidelity Mars analog environment with a focus on astrobiology and operations research that has been optimized to reduce the amount of biological cross contamination. We report on the performance envelope of the Aouda.X system and its operational limitations.

Experimental and Monte Carlo simulated spectra of a liquid-metal-jet x-ray source

International Nuclear Information System (INIS)

Marziani, M.; Gambaccini, M.; Di Domenico, G.; Taibi, A.; Cardarelli, P.

2014-01-01

A prototype x-ray system based on a liquid-metal-jet anode was evaluated within the framework of the LABSYNC project. The generated spectrum was measured using a CZT-based spectrometer and was compared with spectra simulated by three Monte Carlo codes: MCNPX, PENELOPE and EGS5. Notable differences in the simulated spectra were found. These are mainly attributable to differences in the models adopted for the electron-impact ionization cross section. The simulation that more closely reproduces the experimentally measured spectrum was provided by PENELOPE. - Highlights: • The x-ray spectrum of a liquid-jet x-ray anode was measured with a CZT spectrometer. • Results were compared with Monte Carlo simulations using MCNPX, PENELOPE, EGS5. • Notable differences were found among the Monte Carlo simulated spectra. • The key role was played by the electron-impact ionization cross-section model used. • The experimentally measured spectrum was closely reproduced by the PENELOPE code

Multispectral Terrain Background Simulation Techniques For Use In Airborne Sensor Evaluation

Science.gov (United States)

Weinberg, Michael; Wohlers, Ronald; Conant, John; Powers, Edward

1988-08-01

A background simulation code developed at Aerodyne Research, Inc., called AERIE is designed to reflect the major sources of clutter that are of concern to staring and scanning sensors of the type being considered for various airborne threat warning (both aircraft and missiles) sensors. The code is a first principles model that could be used to produce a consistent image of the terrain for various spectral bands, i.e., provide the proper scene correlation both spectrally and spatially. The code utilizes both topographic and cultural features to model terrain, typically from DMA data, with a statistical overlay of the critical underlying surface properties (reflectance, emittance, and thermal factors) to simulate the resulting texture in the scene. Strong solar scattering from water surfaces is included with allowance for wind driven surface roughness. Clouds can be superimposed on the scene using physical cloud models and an analytical representation of the reflectivity obtained from scattering off spherical particles. The scene generator is augmented by collateral codes that allow for the generation of images at finer resolution. These codes provide interpolation of the basic DMA databases using fractal procedures that preserve the high frequency power spectral density behavior of the original scene. Scenes are presented illustrating variations in altitude, radiance, resolution, material, thermal factors, and emissivities. The basic models utilized for simulation of the various scene components and various "engineering level" approximations are incorporated to reduce the computational complexity of the simulation.

FERO (Finding Extreme Relativistic Objects): statistics of relativistic broad Fe Kalpha lines in AGN

Czech Academy of Sciences Publication Activity Database

Longinotti, A. L.; de La Calle, I.; Bianchi, S.; Guainazzi, M.; Dovčiak, Michal

2008-01-01

Roč. 79, č. 1 (2008), s. 259-261 ISSN 0037-8720. [ Simbol -X: The hard X-ray Universe in focus. Bologna, 14.05.2007-16.05.2007] Institutional research plan: CEZ:AV0Z10030501 Keywords : active galaxies * X-raylLines-iron Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

The simulation of charge sharing in semiconductor X-ray pixel detectors

CERN Document Server

Mathieson, K; O'Shea, V; Passmore, M S; Rahman, M; Smith, K M; Watt, J; Whitehill, C

2002-01-01

Two simulation packages were used to model the sharing of charge, due to the scattering and diffusion of carriers, between adjacent pixel elements in semiconductors X-ray detectors. The X-ray interaction and the consequent multiple scattering was modelled with the aid of the Monte Carlo package, MCNP. The resultant deposited charge distribution was then used to create the charge cloud profile in the finite element semiconductor simulation code MEDICI. The analysis of the current pulses induced on pixel electrodes for varying photon energies was performed for a GaAs pixel detector. For a pixel pitch of 25 mu m, the charge lost to a neighbouring pixel was observed to be constant, at 0.6%, through the energies simulated. Ultimately, a fundamental limit on the pixel element size for imaging and spectroscopic devices may be set due to these key physical principles.

Variance analysis of x-ray CT sinograms in the presence of electronic noise background.

Science.gov (United States)

Ma, Jianhua; Liang, Zhengrong; Fan, Yi; Liu, Yan; Huang, Jing; Chen, Wufan; Lu, Hongbing

2012-07-01

Low-dose x-ray computed tomography (CT) is clinically desired. Accurate noise modeling is a fundamental issue for low-dose CT image reconstruction via statistics-based sinogram restoration or statistical iterative image reconstruction. In this paper, the authors analyzed the statistical moments of low-dose CT data in the presence of electronic noise background. The authors first studied the statistical moment properties of detected signals in CT transmission domain, where the noise of detected signals is considered as quanta fluctuation upon electronic noise background. Then the authors derived, via the Taylor expansion, a new formula for the mean-variance relationship of the detected signals in CT sinogram domain, wherein the image formation becomes a linear operation between the sinogram data and the unknown image, rather than a nonlinear operation in the CT transmission domain. To get insight into the derived new formula by experiments, an anthropomorphic torso phantom was scanned repeatedly by a commercial CT scanner at five different mAs levels from 100 down to 17. The results demonstrated that the electronic noise background is significant when low-mAs (or low-dose) scan is performed. The influence of the electronic noise background should be considered in low-dose CT imaging.

Beam dynamics simulation in the X-ray Compton source

International Nuclear Information System (INIS)

Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

2002-01-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center

Beam dynamics simulation in the X-ray Compton source

CERN Document Server

Gladkikh, P; Telegin, Yu P; Shcherbakov, A; Zelinsky, A

2002-01-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

Physics validation studies for muon collider detector background simulations

International Nuclear Information System (INIS)

Morris, Aaron Owen

2011-01-01

Within the broad discipline of physics, the study of the fundamental forces of nature and the most basic constituents of the universe belongs to the field of particle physics. While frequently referred to as 'high-energy physics,' or by the acronym 'HEP,' particle physics is not driven just by the quest for ever-greater energies in particle accelerators. Rather, particle physics is seen as having three distinct areas of focus: the cosmic, intensity, and energy frontiers. These three frontiers all provide different, but complementary, views of the basic building blocks of the universe. Currently, the energy frontier is the realm of hadron colliders like the Tevatron at Fermi National Accelerator Laboratory (Fermilab) or the Large Hadron Collider (LHC) at CERN. While the LHC is expected to be adequate for explorations up to 14 TeV for the next decade, the long development lead time for modern colliders necessitates research and development efforts in the present for the next generation of colliders. This paper focuses on one such next-generation machine: a muon collider. Specifically, this paper focuses on Monte Carlo simulations of beam-induced backgrounds vis-a-vis detector region contamination. Initial validation studies of a few muon collider physics background processes using G4beamline have been undertaken and results presented. While these investigations have revealed a number of hurdles to getting G4beamline up to the level of more established simulation suites, such as MARS, the close communication between us, as users, and the G4beamline developer, Tom Roberts, has allowed for rapid implementation of user-desired features. The main example of user-desired feature implementation, as it applies to this project, is Bethe-Heitler muon production. Regarding the neutron interaction issues, we continue to study the specifics of how GEANT4 implements nuclear interactions. The GEANT4 collaboration has been contacted regarding the minor discrepancies in the neutron

Radiography simulation on single-shot dual-spectrum X-ray for cargo inspection system

International Nuclear Information System (INIS)

Gil, Youngmi; Oh, Youngdo; Cho, Moohyun; Namkung, Won

2011-01-01

We propose a method to identify materials in the dual energy X-ray (DeX) inspection system. This method identifies materials by combining information on the relative proportions T of high-energy and low-energy X-rays transmitted through the material, and the ratio R of the attenuation coefficient of the material when high-energy are used to that when low energy X-rays are used. In Monte Carlo N-Particle Transport Code (MCNPX) simulations using the same geometry as that of the real container inspection system, this T vs. R method successfully identified tissue-equivalent plastic and several metals. In further simulations, the single-shot mode of operating the accelerator led to better distinguishing of materials than the dual-shot system.

OI Fluorescent Line Contamination in Soft X-Ray Diffuse Background Obtained with Suzaku/XIS

OpenAIRE

Sekiya, Norio; Yamasaki, Noriko Y.; Mitsuda, Kazuhisa; Takei, Yoh

2014-01-01

The quantitative measurement of OVII line intensity is a powerful method for understanding the soft X-ray diffuse background. By systematically analyzing the OVII line intensity in 145 high-latitude Suzaku/XIS observations, the flux of OI fluorescent line in the XIS spectrum, contaminating the OVII line, is found to have an increasing trend with time especially after 2011. For these observations, the OVII line intensity would be overestimated unless taking into consideration the OI fluorescen...

Soft x-ray virtual diagnostics for tokamak simulations

Science.gov (United States)

Kim, J. S.; Zhao, L.; Bogatu, I. N.; In, Y.; Turnbull, A.; Osborne, T.; Maraschek, M.; Comer, K.

2009-11-01

The numerical toolset, FAR-TECH Virtual Diagnostic Utility, for generating virtual experimental data based on theoretical models and comparing it with experimental data, has been developed for soft x-ray diagnostics on DIII-D. The virtual (or synthetic) soft x-ray signals for a sample DIII-D discharge are compared with the experimental data. The plasma density and temperature radial profiles needed in the soft x-ray signal modeling are obtained from experimental data, i.e., from Thomson scattering and electron cyclotron emission. The virtual soft x-ray diagnostics for the equilibriums have a good agreement with the experimental data. The virtual diagnostics based on an ideal linear instability also agree reasonably well with the experimental data. The agreements are good enough to justify the methodology presented here for utilizing virtual diagnostics for routine comparison of experimental data. The agreements also motivate further detailed simulations with improved physical models such as the nonideal magnetohydrodynamics contributions (resistivity, viscosity, nonaxisymmetric error fields, etc.) and other nonlinear effects, which can be tested by virtual diagnostics with various stability modeling.

Soft x-ray virtual diagnostics for tokamak simulations

International Nuclear Information System (INIS)

Kim, J. S.; Zhao, L.; Bogatu, I. N.; In, Y.; Turnbull, A.; Osborne, T.; Maraschek, M.; Comer, K.

2009-01-01

The numerical toolset, FAR-TECH Virtual Diagnostic Utility, for generating virtual experimental data based on theoretical models and comparing it with experimental data, has been developed for soft x-ray diagnostics on DIII-D. The virtual (or synthetic) soft x-ray signals for a sample DIII-D discharge are compared with the experimental data. The plasma density and temperature radial profiles needed in the soft x-ray signal modeling are obtained from experimental data, i.e., from Thomson scattering and electron cyclotron emission. The virtual soft x-ray diagnostics for the equilibriums have a good agreement with the experimental data. The virtual diagnostics based on an ideal linear instability also agree reasonably well with the experimental data. The agreements are good enough to justify the methodology presented here for utilizing virtual diagnostics for routine comparison of experimental data. The agreements also motivate further detailed simulations with improved physical models such as the nonideal magnetohydrodynamics contributions (resistivity, viscosity, nonaxisymmetric error fields, etc.) and other nonlinear effects, which can be tested by virtual diagnostics with various stability modeling.

SOLPS simulations of X-divertor in NSTX-U

Science.gov (United States)

Chen, Zhongping; Kotschenreuther, Mike; Mahajan, Swadesh

2017-10-01

The X-divertor (XD) geometry in NSTX-U has demonstrated, in SOLPS simulations, a better performance than the standard divertor (SD) regarding detachment: achieving detachment with a lower upstream density and stabilizing the detachment front near the target. The benefits of such a localized front is that the power exhaust requirement can be satisfied without the radiation front encroaching on the core plasma. It is also found by our simulations that at similar states of detachment the XD outperforms the SD by reducing the heat fluxes to the target and maintaining higher upstream temperatures. These advantages are attributed to the unique geometric characteristics of XD - poloidal flaring near the target. The detailed physical mechanisms behind the better XD performance that is found in the simulations will be examined. Work supported by US DOE under DE-FG02-04ER54742 and SC 0012956.

Compact X-ray sources. Simulating the electron/strong laser interaction

Energy Technology Data Exchange (ETDEWEB)

Hartin, Anthony [DESY, CFEL, Hamburg (Germany)

2016-07-01

The collision of an intense laser with an electron bunch can be used to produce X-rays via the inverse Compton scattering (ICS) mechanism. The ICS can be simulated via either a classical theory in which electrons and photons are treated in terms of classical electromagnetic waves - or a quantum theory in which charged particles interact with strong electromagnetic fields. The laser intensity used in a practical ICS collision is likely to be at such a level that quantum effects may be significant and the use of quantum theory may become a necessity. A simulation study is presented here comparing the classical and quantum approaches to the ICS. A custom particle-in-cell (PIC) software code, with photon generation by monte carlo of the exact quantum transition probability is used to simulate the quantum treatment. Peak resonant energies and the angular distribution of the X-rays are obtained and compared with those predicted by the classical theory. The conditions under which significant differences between the two theories emerges is obtained.

XIMPOL: a new x-ray polarimetry observation-simulation and analysis framework

Science.gov (United States)

Omodei, Nicola; Baldini, Luca; Pesce-Rollins, Melissa; di Lalla, Niccolò

2017-08-01

We present a new simulation framework, XIMPOL, based on the python programming language and the Scipy stack, specifically developed for X-ray polarimetric applications. XIMPOL is not tied to any specific mission or instrument design and is meant to produce fast and yet realistic observation-simulations, given as basic inputs: (i) an arbitrary source model including morphological, temporal, spectral and polarimetric information, and (ii) the response functions of the detector under study, i.e., the effective area, the energy dispersion, the point-spread function and the modulation factor. The format of the response files is OGIP compliant, and the framework has the capability of producing output files that can be directly fed into the standard visualization and analysis tools used by the X-ray community, including XSPEC which make it a useful tool not only for simulating physical systems, but also to develop and test end-to-end analysis chains.

Beam dynamics simulation in the X-ray Compton source

Energy Technology Data Exchange (ETDEWEB)

Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A. E-mail: shcherbakov@kipt.kharkov.ua; Zelinsky, A

2002-05-01

At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

Pemanfaatan Media Pembelajaran Audio Visual Untuk Meningkatkan Hasil Belajar PAI Pada Siswa Kelas V SDN Kalianget Timur X

Directory of Open Access Journals (Sweden)

Ernawati Ernawati

2014-08-01

Full Text Available Proses belajar mengajar pada hakikatnya adalah proses komunikasi, penyampaian pesan dari pengantar ke penerima. Pesan berupa isi/ajaran yang dituangkan ke dalam simbol-simbol komunikasi baik verbal maupun non verbal.Dalam pembelajaran PAI, agar bahan pelajaran yang diberikan lebih mudah dipahami oleh siswa, diperlukan media yang membantu proses penyampaian tersebut.Melalui media (alat bantu, diharapkan akan terjadi persepsi yang sama antara guru dan siswa. Apalagi Pendidikan Agama Islam yakni pendidikan yang sangat penting bagi kehidupan manusia, terutama dalam mencapai ketentraman bathin dan kesehatan mental padaumumnya.Media CD ini bisa digunakan sebagai salah satu alternatif pembelajaran PAI, khususnya pada materi “menceritakan kisah-kisah Nabi”.Melalui film tentang kisah Nabi yang ada dalam kaset CD, tentunya siswa akan lebih mudah memahami dan lebih mengasyikkan untuk digunakan sebagai sarana belajar daripada menggunakan buku ajar biasa yang pada akhirnya berpengaruh terhadap pencapaian hasil belajar siswa. Tujuan yang ingin dicapai melaluipenelitian ini adalah untuk mengetahui keefektifan media CD dalam meningkatkan hasil belajar siswa pada pelajaran PAI materi menceritakan kisah Nabi di kelas V SDN Kalianget Timur X.Berdasarkan hasil yang diperoleh dari siklus I sampai II, pemanfaatan media pembelajaran CD pada materi menceritakan kisah Nabi terbukti dapat meningkatkan hasil belajar siswa. Hal ini terbukti dengan adanya peningkatan hasil belajar baik secara kelompok maupun secara individu. Pemanfaatan media pembelajaran CDjuga dapat meningkatkan aktivitas belajar siswa yang meliputi keaktifan, kerjasama, keberanian, kedisiplinan, serta ketelitian siswa.

An Analysis Of Symbols In Dan Brown’s Novel Angels And Demons

OpenAIRE

Savrizal, Muhammad

2014-01-01

Skripsi ini yang berjudul An Analysis Of Symbols In Dan Brown’s Novel Angels And Demons merupakan sebuah analisis mengenai simbol-simbol dalam novel “Angels and Demons” dan pembagian simbol kedalam bagian-bagian tertentu serta mengidentifikasi makna makna simbol tersebut. Beberapa simbol dalam novel ini merupakan simbol Illuminati yang merupakan bagian dari proses komunikasi yang dilakukan setiap anggota didalam Illuminati untuk sesama anggota. Tujuan penulis menganalisis si...

The X-Ray Pebble Recirculation Experiment (X-PREX): Facility Description, Preliminary Discrete Element Method Simulation Validation Studies, and Future Test Program

International Nuclear Information System (INIS)

Laufer, Michael R.; Bickel, Jeffrey E.; Buster, Grant C.; Krumwiede, David L.; Peterson, Per F.

2014-01-01

This paper presents a facility description, preliminary results, and future test program of the new X-Ray Pebble Recirculation Experiment (X-PREX), which is now operational and being used to collect data on the behavior of slow dense granular flows relevant to pebble bed reactor core designs. The X-PREX facility uses digital x-ray tomography methods to track both the translational and rotational motion of spherical pebbles, which provides unique experimental results that can be used to validate discrete element method (DEM) simulations of pebble motion. The validation effort supported by the X-PREX facility provides a means to build confidence in analysis of pebble bed configuration and residence time distributions that impact the neutronics, thermal hydraulics, and safety analysis of pebble bed reactor cores. Preliminary experimental and DEM simulation results are reported for silo drainage, a classical problem in the granular flow literature, at several hopper angles. These studies include conventional converging and novel diverging geometries that provide additional flexibility in the design of pebble bed reactor cores. Excellent agreement is found between the X-PREX experimental and DEM simulation results. Finally, this paper discusses additional studies in progress relevant to the design and analysis of pebble bed reactor cores including pebble recirculation in cylindrical core geometries and evaluation of forces on shut down blades inserted directly into a packed pebble bed. (author)

Background- and simulated leak-noise measurements on ASB-loop, KNK II- and SNR 300-steam generators

International Nuclear Information System (INIS)

Voss, J.; Arnaoutis, N.; Foerster, K.; Moellerfeld, H.

1990-01-01

During several leak propagation experiments in the ASB sodium loop noise measurements were performed showing the acoustic behaviour of evoluting leaks in a tube bundle section under sodium. Effects like self evolution, secondary leaks and tube ruptures by overheating occurred during these tests and were reflected in the course of acoustic signals. In one of the KNK II steam generators simulated leak noise was detected against background noise throughout the operating power range. Experimental arrangements and results are described. In SNR 300 all of the SGUs are equipped with waveguides and some with accelerometers for background noise measurements. First measurement under isothermal conditions were performed in the past. A gas injection device for acoustic leak simulation is under construction. The design of the experimental acoustic system and first results are presented. (author). 1 ref., 21 figs, 2 tabs

Background simulation for the Spherical Proportional Counter and its use for the detection of optical photons

International Nuclear Information System (INIS)

Bougamont, E; Colas, P; Dastgheibi-Fard, A; Derre, J; Giomataris, I; Gerbier, G; Gros, M; Magnier, P; Navick, X F; Tsiledakis, G; Salin, P; Savvidis, I; Vergados, J D

2013-01-01

The recently developed Spherical Proportional Counter [1] allows to instrument large target masses with good energy resolution and sub-keV energy threshold. The moderate cost of this detector, its simplicity and robustness, makes this technology a promising approach for many domains of physics and applications, like dark matter detection and low energy neutrino searches. Detailed Monte Carlo simulations are essential to evaluate the background level expected at the sub-keV energy regime. The simulated background here, it refers to the contribution of the construction material of the detector and the effect of the environmental gamma radiation. This detector due to its spherical shape could be also served as an optical photon detector provided it is equipped with PMTs, for Double Beta decay and Dark Matter searches. All calculations shown here are obtained using the FLUKA Monte Carlo code

Numerical simulation study for atomic-resolution x-ray fluorescence holography

International Nuclear Information System (INIS)

Xie Honglan; Gao Hongyi; Chen Jianwen; Xiong Shisheng; Xu Zhizhan; Wang Junyue; Zhu Peiping; Xian Dingchang

2003-01-01

Based on the principle of x-ray fluorescence holography, an iron single crystal model of a body-centred cubic lattice is numerically simulated. From the fluorescence hologram produced numerically, the Fe atomic images were reconstructed. The atomic images of the (001), (100), (010) crystallographic planes were consistent with the corresponding atomic positions of the model. The result indicates that one can obtain internal structure images of single crystals at atomic-resolution by using x-ray fluorescence holography

Spectral evolution of active galactic nuclei: A unified description of the X-ray and gamma-ray backgrounds

International Nuclear Information System (INIS)

Letter, D.; Boldt, E.

1982-01-01

A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually have emerged from an earlier stage at zroughly-equal4 in which they are the thermal X-ray sources responsible for most of the comic X-ray background (CXB). We pursue the conjecture that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx.10 8 years these central black holes are spun up to a ''canonical'' Kerr equilibriuim state (a/M = 0.998) and shown how they can lead to spectral evolution involving nonthermal emission extending to gamma-rays, at the expense of reduced thermal disk radiation. A superposition of sources in the precursor stage can thereby account for that major portion of the CXB remaining after the contributions of usual AGN are considered, while a superposition of AGN sources at z<1 can account for the gamima-ray background. Extensive X-ray measurements carried out with the HEAO 1 and HEAO 2 missions, as well as gamma-ray and optical data, are shown to compare favorably with principal features of this model. Several further observational tests are suggested for establishing the validity of this scenario for AGN spectral evolution

IIB backgrounds with five-form flux

International Nuclear Information System (INIS)

Gran, U.; Gutowski, J.; Papadopoulos, G.

2008-01-01

We investigate all N=2 supersymmetric IIB supergravity backgrounds with non-vanishing five-form flux. The Killing spinors have stability subgroups Spin(7) x R 8 , SU(4) x R 8 and G 2 . In the SU(4) x R 8 case, two different types of geometry arise depending on whether the Killing spinors are generic or pure. In both cases, the backgrounds admit a null Killing vector field which leaves invariant the SU(4) x R 8 structure, and an almost complex structure in the directions transverse to the lightcone. In the generic case, the twist of the vector field is trivial but the almost complex structure is non-integrable, while in the pure case the twist is non-trivial but the almost complex structure is integrable and associated with a relatively balanced Hermitian structure. The G 2 backgrounds admit a time-like Killing vector field and two spacelike closed one-forms, and the seven directions transverse to these admit a co-symplectic G 2 structure. The Spin(7) x R 8 backgrounds are pp-waves propagating in an eight-dimensional manifold with holonomy Spin(7). In addition we show that all the supersymmetric solutions of simple five-dimensional supergravity with a time-like Killing vector field, which include the AdS 5 black holes, lift to SU(4) x R 8 pure Killing spinor IIB backgrounds. We also show that the LLM solution is associated with a co-symplectic co-homogeneity one G 2 manifold which has principal orbit S 3 xS 3

Laboratory simulation of charge exchange-produced X-ray emission from comets.

Science.gov (United States)

Beiersdorfer, P; Boyce, K R; Brown, G V; Chen, H; Kahn, S M; Kelley, R L; May, M; Olson, R E; Porter, F S; Stahle, C K; Tillotson, W A

2003-06-06

In laboratory experiments using the engineering spare microcalorimeter detector from the ASTRO-E satellite mission, we recorded the x-ray emission of highly charged ions of carbon, nitrogen, and oxygen, which simulates charge exchange reactions between heavy ions in the solar wind and neutral gases in cometary comae. The spectra are complex and do not readily match predictions. We developed a charge exchange emission model that successfully reproduces the soft x-ray spectrum of comet Linear C/1999 S4, observed with the Chandra X-ray Observatory.

Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

Energy Technology Data Exchange (ETDEWEB)

Cappelluti, N.; Urry, M. [Yale Center for Astronomy and Astrophysics, P.O. Box 208120, New Haven, CT 06520 (United States); Arendt, R. [University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kashlinsky, A. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Li, Y.; Hasinger, G. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Helgason, K. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Natarajan, P. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Finoguenov, A. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, D-85741, Garching bei München (Germany)

2017-09-20

We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer -IRAC cosmic infrared background and Chandra -ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ∼12 Ms of Chandra data collected over a total area of 0.3 deg{sup 2}. We report the first (>5 σ ) detection of a cross-power signal on large angular scales >20″ between [0.5–2] keV and the 3.6 and 4.5 μ m bands, at ∼5 σ and 6.3 σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5 σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

Combined synthetic x-ray and radio observations of simulated radio jets

Energy Technology Data Exchange (ETDEWEB)

Tregillis, I. L. (Ian L.); Jones, T. W. (Thomas Walter),; Ryu, Dongsu

2004-01-01

We present results from an extensive synthetic observation analysis of numerically-simulated radio galaxy jets. This is the first such analysis to be based on simulations with sufficient physical detail to allow the application of standard observational analysis techniques to simulated radio galaxies. Here we focus on extracting magnetic field properties from nonthermal intensity information. We study field values obtained via the combination of synchrotron radio and inverse-Compton X-ray data as well as those from the minimum-energy approach. The combined radio/X-ray technique provides meaningful information about the field. The minimum-energy approach retrieves reasonable field estimates in regions physically close to the minimum-energy partitioning, though the technique is highly susceptible to deviations from the underlying assumptions. We also look at how the two field measurement techniques might be combined to provide a rough measure of the actual energy in particles and fields. A full report on this work can be found in the Astrophysical Journal, v601, p778.

The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

Science.gov (United States)

Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.;

GEANT4 simulation of the neutron background of the C{sub 6}D{sub 6} set-up for capture studies at n{sub T}OF

Energy Technology Data Exchange (ETDEWEB)

Žugec, P., E-mail: pzugec@phy.hr [Department of Physics, Faculty of Science, University of Zagreb (Croatia); Colonna, N. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Bosnar, D. [Department of Physics, Faculty of Science, University of Zagreb (Croatia); Altstadt, S. [Johann-Wolfgang-Goethe Universität, Frankfurt (Germany); Andrzejewski, J. [Uniwersytet Łódzki, Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3 – IPN, Orsay (France); Barbagallo, M. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Bécares, V. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Bečvář, F. [Charles University, Prague (Czech Republic); Belloni, F. [Commissariat à l' Énergie Atomique (CEA) Saclay – Irfu, Gif-sur-Yvette (France); Berthoumieux, E. [Commissariat à l' Énergie Atomique (CEA) Saclay – Irfu, Gif-sur-Yvette (France); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Billowes, J. [University of Manchester, Oxford Road, Manchester (United Kingdom); Boccone, V.; Brugger, M.; Calviani, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Calviño, F. [Universitat Politecnica de Catalunya, Barcelona (Spain); Cano-Ott, D. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Carrapiço, C. [Instituto Tecnológico e Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisboa (Portugal); Cerutti, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); and others

2014-10-01

The neutron sensitivity of the C{sub 6}D{sub 6} detector setup used at n{sub T}OF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n{sub T}OF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a {sup nat}C sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured {sup nat}C yield has been discovered, which prevents the use of {sup nat}C data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron background for two different samples are demonstrating the important role of accurate simulations of the neutron background in capture cross-section measurements.

Numerical simulation of X90 UOE pipe forming process

Science.gov (United States)

Zou, Tianxia; Ren, Qiang; Peng, Yinghong; Li, Dayong; Tang, Ding; Han, Jianzeng; Li, Xinwen; Wang, Xiaoxiu

2013-12-01

The UOE process is an important technique to manufacture large-diameter welding pipes which are increasingly applied in oil pipelines and offshore platforms. The forming process of UOE mainly consists of five successive operations: crimping, U-forming, O-forming, welding and mechanical expansion, through which a blank is formed into a pipe in a UOE pipe mill. The blank with an appropriate edge bevel is bent into a cylindrical shape by crimping (C-forming), U-forming and O-forming successively. After the O-forming, there is an open-seam between two ends of the plate. Then, the blank is welded by automatic four-electrode submerged arc welding technique. Subsequently, the welded pipe is expanded with a mechanical expander to get a high precision circular shape. The multiple operations in the UOE mill make it difficult to control the quality of the formed pipe. Therefore, process design mainly relies on experience in practical production. In this study, the UOE forming of an API X90 pipe is studied by using finite element simulation. The mechanical properties tests are performed on the API X90 pipeline steel blank. A two-dimensional finite element model under the hypothesis of plane strain condition is developed to simulate the UOE process according to data coming from the workshop. A kinematic hardening model is used in the simulation to take the Bauschinger effect into account. The deformation characteristics of the blank during the forming processes are analyzed. The simulation results show a significant coherence in the geometric configurations comparing with the practical manufacturing.

Monte Carlo Simulation of Complete X-Ray Spectra for Use in Scanning Electron Microscopy Analysis

International Nuclear Information System (INIS)

Roet, David; Van Espen, Piet

2003-01-01

Full Text: The interactions of keV electrons and photons with matter can be simulated accurately with the aid of the Monte Carlo (MC) technique. In scanning electron microscopy x-ray analysis (SEM-EDX) such simulations can be used to perform quantitative analysis using a Reverse Monte Carlo method even if the samples have irregular geometry. Alternatively the MC technique can generate spectra of standards for use in quantization with partial least squares regression. The feasibility of these alternatives to the more classical ZAF or phi-rho-Z quantification methods has been proven already. In order to be applicable for these purposes the MC-code needs to generate accurately only the characteristic K and L x-ray lines, but also the Bremsstrahlung continuum, i.e. the complete x-ray spectrum need to be simulated. Currently two types of MC simulation codes are available. Programs like Electron Flight Simulator and CASINO simulate characteristic x-rays due to electron interaction in a fast and efficient way but lack provision for the simulation of the continuum. On the other hand, programs like EGS4, MCNP4 and PENELOPE, originally developed for high energy (MeV- GeV) applications, are more complete but difficult to use and still slow, even on todays fastest computers. We therefore started the development of a dedicated MC simulation code for use in quantitative SEM-EDX work. The selection of the most appropriate cross section for the different interactions will be discussed and the results obtained will be compared with those obtained with existing MC programs. Examples of the application of MC simulations for quantitative analysis of samples with various composition will be given

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources.

Science.gov (United States)

Tang, M X; Zhang, Y Y; E, J C; Luo, S N

2018-05-01

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic-plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of the diffraction patterns is discussed.

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources

Energy Technology Data Exchange (ETDEWEB)

Tang, M. X.; Zhang, Y. Y.; E, J. C.; Luo, S. N.

2018-04-24

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic–plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of the diffraction patterns is discussed.

Characterization, propagation, and simulation of sources and backgrounds II; Proceedings of the Meeting, Orlando, FL, Apr. 20-22, 1992

Science.gov (United States)

Clement, Dieter; Watkins, Wendell R.

Consideration is given to a characterization of the environmental influence on targets, backgrounds, camouflage, and clutter; modeling of physically based dynamics of scene radiation and its propagation; and the relatively sophisticated real-time simulations/simulators for system observer display and testing of some of these dynamic and varied scene changes. Particular attention is given to the hardware-in-the-loop infrared projector technology, a strategic scene generation model, a comparison of night sky spectral radiance measurements with MODTRAN and LOWTRAN 7 predictions, spatiotemporal models for the simulation of infrared backgrounds, computer-based evaluation of camouflage, dual-band infrared polarization measurements of sun glint from the sea surface, an electron gun IR scenario simulator, relaxation processes of vibrationally excited species in the mesosphere and thermosphere, a fiber-optic-based device for the investigation of aerooptic effects, and luminous intensity measurements of sources using a new detector-based illuminance scale. (For individual items see A93-28623 to A93-28625)

Caliste 64, a new CdTe micro-camera for hard X-ray spectro-imaging

Science.gov (United States)

Meuris, A.; Limousin, O.; Lugiez, F.; Gevin, O.; Blondel, C.; Pinsard, F.; Vassal, M. C.; Soufflet, F.; Le Mer, I.

2009-10-01

In the frame of the Simbol-X mission of hard X-ray astrophysics, a prototype of micro-camera with 64 pixels called Caliste 64 has been designed and several samples have been tested. The device integrates ultra-low-noise IDeF-X V1.1 ASICs from CEA and a 1 cm 2 Al Schottky CdTe detector from Acrorad because of its high uniformity and spectroscopic performance. The process of hybridization, mastered by the 3D Plus company, respects space applications standards. The camera is a spectro-imager with time-tagging capability. Each photon interacting in the semiconductor is tagged with a time, a position and an energy. Time resolution is better than 100 ns rms for energy deposits greater than 20 keV, taking into account electronic noise and technological dispersal of the front-end electronics. The spectrum summed across the 64 pixels results in an energy resolution of 664 eV fwhm at 13.94 keV and 842 eV fwhm at 59.54 keV, when the detector is cooled down to -10 °C and biased at -500 V.

Caliste 64, a new CdTe micro-camera for hard X-ray spectro-imaging

International Nuclear Information System (INIS)

Meuris, A.; Limousin, O.; Lugiez, F.; Gevin, O.; Blondel, C.; Pinsard, F.; Vassal, M.C.; Soufflet, F.; Le Mer, I.

2009-01-01

In the frame of the Simbol-X mission of hard X-ray astrophysics, a prototype of micro-camera with 64 pixels called Caliste 64 has been designed and several samples have been tested. The device integrates ultra-low-noise IDeF-X V1.1 ASICs from CEA and a 1 cm 2 Al Schottky CdTe detector from Acrorad because of its high uniformity and spectroscopic performance. The process of hybridization, mastered by the 3D Plus company, respects space applications standards. The camera is a spectro-imager with time-tagging capability. Each photon interacting in the semiconductor is tagged with a time, a position and an energy. Time resolution is better than 100 ns rms for energy deposits greater than 20 keV, taking into account electronic noise and technological dispersal of the front-end electronics. The spectrum summed across the 64 pixels results in an energy resolution of 664 eV fwhm at 13.94 keV and 842 eV fwhm at 59.54 keV, when the detector is cooled down to -10 deg. C and biased at -500 V.

Caliste 64, a new CdTe micro-camera for hard X-ray spectro-imaging

Energy Technology Data Exchange (ETDEWEB)

Meuris, A. [CEA, Irfu, Service d' Astrophysique, Bat. 709, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)], E-mail: aline.meuris@cea.fr; Limousin, O. [CEA, Irfu, Service d' Astrophysique, Bat. 709, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Lugiez, F.; Gevin, O. [CEA, Irfu, Service d' Electronique, de Detecteurs et d' Informatique, F-91191 Gif-sur-Yvette (France); Blondel, C.; Pinsard, F. [CEA, Irfu, Service d' Astrophysique, Bat. 709, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Vassal, M.C.; Soufflet, F. [3D Plus, 641 rue Helene Boucher, F-78532 Buc (France); Le Mer, I. [CEA, Irfu, Service d' Astrophysique, Bat. 709, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)

2009-10-21

In the frame of the Simbol-X mission of hard X-ray astrophysics, a prototype of micro-camera with 64 pixels called Caliste 64 has been designed and several samples have been tested. The device integrates ultra-low-noise IDeF-X V1.1 ASICs from CEA and a 1 cm{sup 2} Al Schottky CdTe detector from Acrorad because of its high uniformity and spectroscopic performance. The process of hybridization, mastered by the 3D Plus company, respects space applications standards. The camera is a spectro-imager with time-tagging capability. Each photon interacting in the semiconductor is tagged with a time, a position and an energy. Time resolution is better than 100 ns rms for energy deposits greater than 20 keV, taking into account electronic noise and technological dispersal of the front-end electronics. The spectrum summed across the 64 pixels results in an energy resolution of 664 eV fwhm at 13.94 keV and 842 eV fwhm at 59.54 keV, when the detector is cooled down to -10 deg. C and biased at -500 V.

Background Acoustics Levels in the 9x15 Wind Tunnel and Linear Array Testing

Science.gov (United States)

Stephens, David

2011-01-01

The background noise level in the 9x15 foot wind tunnel at NASA Glenn has been documented, and the results compare favorably with historical measurements. A study of recessed microphone mounting techniques was also conducted, and a recessed cavity with a micronic wire mesh screen reduces hydrodynamic noise by around 10 dB. A three-microphone signal processing technique can provide additional benefit, rejecting up to 15 dB of noise contamination at some frequencies. The screen and cavity system offers considerable benefit to test efficiency, although there are additional calibration requirements.

Navy DD(X) and CG(X) Program: Background and Issues for Congress

National Research Council Canada - National Science Library

O'Rourke, Ronald

2005-01-01

The FY2006-FY2011 Future Years Defense Plan (FYDP) reduces planned DD(X) destroyer procurement to one ship per year in FY2007-FY2011 and accelerates procurement of the first CG(X) cruiser to FY2011...

A Micromegas-based low-background x-ray detector coupled to a slumped-glass telescope for axion research

DEFF Research Database (Denmark)

Aznar, F.; Castel, J.; Christensen, F. E.

2015-01-01

We report on the design, construction and operation of a low background x-ray detection line composed of a shielded Micromegas detector of the microbulk technology. The detector is made from radiopure materials and is placed at the focal point of a ~ 5 cm diameter, 1.5 m focal-length, cone......-approximation Wolter I x-ray telescope (XRT) assembled from thermally-formed (or "slumped") glass substrates deposited with multilayer coatings. The system has been conceived as a technological pathfinder for the future International Axion Observatory (IAXO), as it combines two of the techniques (optic and detector...

IMPROVED SIMULATION OF NON-GAUSSIAN TEMPERATURE AND POLARIZATION COSMIC MICROWAVE BACKGROUND MAPS

International Nuclear Information System (INIS)

Elsner, Franz; Wandelt, Benjamin D.

2009-01-01

We describe an algorithm to generate temperature and polarization maps of the cosmic microwave background (CMB) radiation containing non-Gaussianity of arbitrary local type. We apply an optimized quadrature scheme that allows us to predict and control integration accuracy, speed up the calculations, and reduce memory consumption by an order of magnitude. We generate 1000 non-Gaussian CMB temperature and polarization maps up to a multipole moment of l max = 1024. We validate the method and code using the power spectrum and the fast cubic (bispectrum) estimator and find consistent results. The simulations are provided to the community.

MCNP6 simulation of radiographs generated from megaelectron volt X-rays for characterizing a computed tomography system

Science.gov (United States)

Dooraghi, Alex A.; Tringe, Joseph W.

2018-04-01

To evaluate conventional munition, we simulated an x-ray computed tomography (CT) system for generating radiographs from nominal x-ray energies of 6 or 9 megaelectron volts (MeV). CT simulations, informed by measured data, allow for optimization of both system design and acquisition techniques necessary to enhance image quality. MCNP6 radiographic simulation tools were used to model ideal detector responses (DR) that assume either (1) a detector response proportional to photon flux (N) or (2) a detector response proportional to energy flux (E). As scatter may become significant with MeV x-ray systems, simulations were performed with and without the inclusion of object scatter. Simulations were compared against measurements of a cylindrical munition component principally composed of HMX, tungsten and aluminum encased in carbon fiber. Simulations and measurements used a 6 MeV peak energy x-ray spectrum filtered with 3.175 mm of tantalum. A detector response proportional to energy which includes object scatter agrees to within 0.6 % of the measured line integral of the linear attenuation coefficient. Exclusion of scatter increases the difference between measurement and simulation to 5 %. A detector response proportional to photon flux agrees to within 20 % when object scatter is included in the simulation and 27 % when object scatter is excluded.

Bremsstrahlung background and quantitation of thin biological samples

International Nuclear Information System (INIS)

Khan, K.M.

1991-02-01

An inherent feature of all electron-excited X-ray spectra is the presence of a background upon which the characteristic peaks of interest are superimposed. To extract the x-ray intensity of the characteristics lines of interest, it is necessary to subtract this background, which may be due to both specimen generated Bremsstrahlung and extraneous sources, from a measured x-ray spectrum. Some conventional methods of background subtraction will be briefly reviewed. It has been seen that these conventional methods do not give sufficiently accurate results in biological analysis where the peaks of interest are not well-separated and most of the peaks lie in the region where the background is appreciably curved. An alternative approach of background subtraction for such samples is investigated which involves modelling the background using the currently available knowledge of x-ray physics and energy dispersive detectors. This method is particularly suitable for biological samples as well as other samples having an organic matrix. 6 figs. (author)

Simulations of X-ray synchrotron beams using the EGS4 code system in medical applications

International Nuclear Information System (INIS)

Orion, I.; Henn, A.; Sagi, I.; Dilmanian, F.A.; Pena, L.; Rosenfeld, A.B.

2001-01-01

X-ray synchrotron beams are commonly used in biological and medical research. The availability of intense, polarized low-energy photons from the synchrotron beams provides a high dose transfer to biological materials. The EGS4 code system, which includes the photoelectron angular distribution, electron motion inside a magnetic field, and the LSCAT package, found to be the appropriate Monte Carlo code for synchrotron-produced X-ray simulations. The LSCAT package was developed in 1995 for the EGS4 code to contain the routines to simulate the linear polarization, the bound Compton, and the incoherent scattering functions. Three medical applications were demonstrated using the EGS4 Monte Carlo code as a proficient simulation code system for the synchrotron low-energy X-ray source. (orig.)

Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources

Energy Technology Data Exchange (ETDEWEB)

Sisniega, A.; Vaquero, J. J., E-mail: juanjose.vaquero@uc3m.es [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Desco, M. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid ES28029 (Spain)

2014-01-15

Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in

Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources

International Nuclear Information System (INIS)

Sisniega, A.; Vaquero, J. J.; Desco, M.

2014-01-01

Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in

The projected background for the CUORE experiment

Energy Technology Data Exchange (ETDEWEB)

Alduino, C.; Avignone, F.T.; Chott, N.; Creswick, R.J.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Alfonso, K.; Hickerson, K.P.; Huang, H.Z.; Sakai, M.; Schmidt, J.; Trentalange, S.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Artusa, D.R.; Rusconi, C. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Azzolini, O.; Camacho, A.; Keppel, G.; Palmieri, V.; Pira, C. [INFN-Laboratori Nazionali di Legnaro, Padua (Italy); Banks, T.I.; Drobizhev, A.; Freedman, S.J.; Hennings-Yeomans, R.; Kolomensky, Yu.G.; Wagaarachchi, S.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bari, G.; Deninno, M.M. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J.W. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cosmelli, C.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Benato, G.; Singh, V. [University of California, Department of Physics, Berkeley, CA (United States); Bersani, A.; Caminata, A. [INFN-Sezione di Genova, Genoa (Italy); Biassoni, M.; Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Fiorini, E.; Gironi, L.; Gotti, C.; Maino, M.; Nastasi, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Branca, A.; Taffarello, L. [INFN-Sezione di Padova, Padua (Italy); Bucci, C.; Cappelli, L.; D' Addabbo, A.; Gorla, P.; Pattavina, L.; Pirro, S.; Laubenstein, M. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Canonica, L. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Massachusetts Institute of Technology, Cambridge, MA (United States); Cao, X.G.; Fang, D.Q.; Ma, Y.G.; Wang, H.W.; Zhang, G.Q. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai (China); Carbone, L.; Cremonesi, O.; Ferri, E.; Giachero, A.; Pessina, G.; Previtali, E. [INFN-Sezione di Milano Bicocca, Milan (Italy); Cardani, L.; Casali, N.; Dafinei, I.; Morganti, S.; Mosteiro, P.J.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Copello, S.; Di Domizio, S.; Fernandes, G.; Marini, L.; Pallavicini, M. [INFN-Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Cushman, J.S.; Davis, C.J.; Heeger, K.M.; Lim, K.E.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Dell' Oro, S. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); INFN-Gran Sasso Science Institute, L' Aquila (Italy); Di Vacri, M.L.; Santone, D. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, L' Aquila (Italy); Franceschi, M.A.; Ligi, C.; Napolitano, T. [INFN-Laboratori Nazionali di Frascati, Rome (Italy); Fujikawa, B.K.; Mei, Y.; Schmidt, B.; Smith, A.R.; Welliver, B. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Giuliani, A.; Novati, V.; Tenconi, M. [Universit Paris-Saclay, CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Orsay (France); Gladstone, L.; Leder, A.; Ouellet, J.L.; Winslow, L.A. [Massachusetts Institute of Technology, Cambridge, MA (United States); Gutierrez, T.D. [California Polytechnic State University, Physics Department, San Luis Obispo, CA (United States); Haller, E.E. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); University of California, Department of Materials Science and Engineering, Berkeley, CA (United States); Han, K. [Shanghai Jiao Tong University, Department of Physics and Astronomy, Shanghai (China); Hansen, E. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Scienze per la Qualita della Vita, Bologna (Italy); Nones, C. [CEA/Saclay, Service de Physique des Particules, Gif-sur-Yvette (France); Norman, E.B.; Wang, B.S. [Lawrence Livermore National Laboratory, Livermore, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); O' Donnell, T. [Virginia Polytechnic Institute and State University, Center for Neutrino Physics, Blacksburg, VA (United States); Pagliarone, C.E. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Universita degli Studi di Cassino e del Lazio Meridionale, Dipartimento di Ingegneria Civile e Meccanica, Cassino (Italy); Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Wise, T. [Yale University, Department of Physics, New Haven, CT (United States); University of Wisconsin, Department of Physics, Madison, WI (United States); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (United Kingdom); Zimmermann, S. [Lawrence Berkeley National Laboratory, Engineering Division, Berkeley, CA (United States); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy)

2017-08-15

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of {sup 130}Te with an array of 988 TeO{sub 2} bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the {sup 130}Te decay half-life of 9 x 10{sup 25} years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, which must not be higher than 10{sup -2} counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of {sup 130}Te is expected. (orig.)

Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

Science.gov (United States)

Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan

2017-06-01

A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

Simulation of single spin asymmetry in the p↑p→π±,0X reaction

International Nuclear Information System (INIS)

Musul'manbekov, Zh.Zh.; Tokarev, M.V.

1995-01-01

Using hadronic event generator based on the Bremsstrahlung approach on hadron level, the left-right asymmetry of inclusive pions in single spin proton-proton collisions was simulated. The x F - and p T -dependencies of asymmetry for the p↑p→π ±,0 X process at E Lab =13, 18, 40 and 200 GeV have been obtained. An analysis of simulated events has been performed and it has been found that Δ-resonances play an important role in the behaviour of pion asymmetry. Some predictions for pion asymmetry are given for high x F and p T region. 14 refs., 5 figs., 2 tabs

Turbulence simulations of X point physics on the L-H transitions

International Nuclear Information System (INIS)

Xu, X.Q.; Cohen, R.H.; Nevins, W.M.

2001-01-01

We show that the resistive X-point mode is the dominant mode in boundary plasmas in X-point divertor geometry. The poloidal fluctuation phase velocity from the simulation results of the resistive X-point turbulence shows experimentally measured structure across separatrix in many fusion devices. The fluctuation phase velocity is larger than ExB velocity both in L and H mode phases. We also demonstrate that there is a strong poloidal asymmetry of particle flux in the proximity of the separatrix. Turbulence suppression in the L-H transition results when sources of energy and particles drive sufficient gradients as in the experiments. (author)

A study of X-divertor in NSTX-U with SOLPS simulations

Science.gov (United States)

Chen, Zhong-Ping; Kotschenreuther, Mike; Mahajan, Swadesh; Gerhardt, Stefan

2018-03-01

The X-divertor (XD) geometry in NSTX-U is demonstrated, via SOLPS simulations, to perform better than the standard divertor (SD); in particular, it allows detachment at a lower upstream density and stabilizes the detachment front near the target, away from the main X-point. Consequently a stable detached operation becomes possible—the localization near the plate allows a vast reduction of heat fluxes without degrading the core plasma. Indeed, it is confirmed by our simulation that at similar states of detachment the XD outperforms the SD by reducing the heat fluxes to the target and maintaining higher upstream temperatures, resulting in scrape-off layers that are more favorable for advanced tokamak operation. These advantages are attributed to the unique geometric characteristics of XD—poloidal flaring near the target.

Performance simulation of the X-ray spectrometer in Chang'E-1 satellite payload

International Nuclear Information System (INIS)

Cao Xuelei; Wang Huanyu; Zhang Chengmo; Chen Yong; Yang Jiawei; Wang JInzhou; Liang Xiaohua; Gao Min; Zhang Jiayu; Ma Guofeng

2007-01-01

We discuss the performance simulation of the X-ray Spectrometer in Chang'E-1 satellite based on Geant4 system. It is divided in three parts, the efficiency simulation, the energy spectrum response and direction response. It provides the guidance on making the spectrometer. (authors)

Background sources at PEP

International Nuclear Information System (INIS)

Lynch, H.; Schwitters, R.F.; Toner, W.T.

1988-01-01

Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, γ-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs

Evaluation of body simulator for chest and abdomen in digital X-ray equipment

International Nuclear Information System (INIS)

Soares, Sidney S.; Cardoso, Gabriela P.; Oliveira, Giovanni Antônio P.; Batista, Adriana S.M.; Pereira, Esther Lorrayne M.

2017-01-01

The use of body simulators to control the quality of X-ray images is a practice that guarantees the control of essential parameters for diagnosis by the technique. The evolution of the equipment, between the analogue, digital computerized radiology (CR) and direct radiography (DR), requires evaluation of the equivalence in grayscale, of simulators, for an adjustment according to the specific technology of obtaining the image. In this sense, the present work presents the evaluation of a body simulator with regard to the representation of mean values of signal, noise and contrast obtained in chest radiographs and panoramic of the abdomen. For the thorax the cardiac region was considered as simulation target and for the abdomen simulation of the liver and small intestine. We used a retrospective study of images obtained with X-ray equipment - CR system, in which the images were studied using the ImageJ program, generating a data catalog. These were subsequently compared with those obtained experimentally using gel filled polymer body simulator. For the validation of the simulator, it was observed the gel equivalence of filling of the polymer box required to reach the image parameters of the cataloged radiographs. The results are discussed as to the physical principles of radiation interaction with biological and equivalent tissues

Measurement of fast neutron background in SAGE

International Nuclear Information System (INIS)

Abdurashitov, J.N.; Gavrin, V.N.; Kalikhov, A.V.; Matushko, V.L.; Shikhin, A.A.; Yants, V.E.; Zaborskaia, O.S.

2002-01-01

The spectrometer intended for direct measurements of ultra low fluxes of fast neutrons is described. It is sensitive to neutron fluxes of 10 -7 cm -2 s -1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 ± 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 ± 2.1) x 10 -7 cm -2 s -1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4700 meters of water equivalent was measured to be (7.3 ± 2.4) x 10 -7 cm -2 s -1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be -7 cm -2 s -1 in 1.0-11.0 MeV energy range

Monte Carlo simulation of X-ray imaging and spectroscopy experiments using quadric geometry and variance reduction techniques

Science.gov (United States)

Golosio, Bruno; Schoonjans, Tom; Brunetti, Antonio; Oliva, Piernicola; Masala, Giovanni Luca

2014-03-01

The simulation of X-ray imaging experiments is often performed using deterministic codes, which can be relatively fast and easy to use. However, such codes are generally not suitable for the simulation of even slightly more complex experimental conditions, involving, for instance, first-order or higher-order scattering, X-ray fluorescence emissions, or more complex geometries, particularly for experiments that combine spatial resolution with spectral information. In such cases, simulations are often performed using codes based on the Monte Carlo method. In a simple Monte Carlo approach, the interaction position of an X-ray photon and the state of the photon after an interaction are obtained simply according to the theoretical probability distributions. This approach may be quite inefficient because the final channels of interest may include only a limited region of space or photons produced by a rare interaction, e.g., fluorescent emission from elements with very low concentrations. In the field of X-ray fluorescence spectroscopy, this problem has been solved by combining the Monte Carlo method with variance reduction techniques, which can reduce the computation time by several orders of magnitude. In this work, we present a C++ code for the general simulation of X-ray imaging and spectroscopy experiments, based on the application of the Monte Carlo method in combination with variance reduction techniques, with a description of sample geometry based on quadric surfaces. We describe the benefits of the object-oriented approach in terms of code maintenance, the flexibility of the program for the simulation of different experimental conditions and the possibility of easily adding new modules. Sample applications in the fields of X-ray imaging and X-ray spectroscopy are discussed. Catalogue identifier: AERO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERO_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland

The Multi-component X-ray Emission of 3C 273

Science.gov (United States)

Soldi, S.; Türler, M.; Paltani, S.; Courvoisier, T. J.-L.

2009-05-01

3C 273 is the brightest quasar in the sky and among the most extensively observed and studied AGN, therefore one of the most suitable targets for a long-term, multi-frequency study. The superposition of a thermal Comptonisation component, similar to that observed in Seyfert galaxies, and of a non-thermal component, related to the jet emission, seems to explain some of the spectral and timing properties of the X-ray emission of 3C 273. Yet, during some observations this dichotomy has not been observed and the variability properties could also be consistent with a single-component scenario, characterised by two parameters varying independently. In order to understand the nature of the X-ray emission in 3C 273, a series of observations up to 80-100 keV, possibly catching the source in different flux states, are essential. Simbol-X will be able to study the emission of 3C 273 in the broad 0.5-80 keV band with high sensitivity, allowing us to disentangle the emission from different spectral components, with 20-30 ks long observations. In addition, the shape and the origin of the high-energy emission of this quasar will be further constrained thanks to the AGILE and Fermi satellites, monitoring the γ-ray sky in the MeV-GeV energy domain.

A comparison of calculated and measured background noise rates in hard X-ray telescopes at balloon altitude

Science.gov (United States)

Dean, A. J.; Dipper, N. A.; Lewis, R. A.; Perotti, F.

1985-01-01

An actively shielded hard X-ray astronomical telescope has been flown on stratospheric balloons. An attempt is made to compare the measured spectral distribution of the background noise counting rates over the energy loss range 20-300 keV with the contributions estimated from a series of Monte Carlo and other computations. The relative contributions of individual particle interactions are assessed.

Measurement of fast neutron background in SAGE

CERN Document Server

Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S

2002-01-01

The spectrometer intended for direct measurements of ultra low fluxes of fast neutrons is described. It is sensitive to neutron fluxes of 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 +- 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 +- 2.1) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4700 meters of water equivalent was measured to be (7.3 +- 2.4) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be < 2.3 x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in 1.0-11.0 MeV energy range.

Virtual X-ray imaging techniques in an immersive casting simulation environment

International Nuclear Information System (INIS)

Li, Ning; Kim, Sung-Hee; Suh, Ji-Hyun; Cho, Sang-Hyun; Choi, Jung-Gil; Kim, Myoung-Hee

2007-01-01

A computer code was developed to simulate radiograph of complex casting products in a CAVE TM -like environment. The simulation is based on the deterministic algorithms and ray tracing techniques. The aim of this study is to examine CAD/CAE/CAM models at the design stage, to optimize the design and inspect predicted defective regions with fast speed, good accuracy and small numerical expense. The present work discusses the algorithms for the radiography simulation of CAD/CAM model and proposes algorithmic solutions adapted from ray-box intersection algorithm and octree data structure specifically for radiographic simulation of CAE model. The stereoscopic visualization of full-size of product in the immersive casting simulation environment as well as the virtual X-ray images of castings provides an effective tool for design and evaluation of foundry processes by engineers and metallurgists

Monte Carlo simulations for stereotactic radiotherapy system with various kilo-voltage x-ray energy

International Nuclear Information System (INIS)

Deloar, H.M.; Kunieda, E.; Kawase, T.; Kubo, Atsushi; Saitoh, H.; Myojoyama, A.; Ozaki, M.; Fujisaki, T.; Saito, K.

2005-01-01

Stereotactic radiotherapy (SRT) of lung tumors with a narrow and precise medium energy x-ray beam where the homogeneous high dose area will be confined within the tumors are desirable. A conventional x-ray CT with medium energy x-ray has been modified to develop a radiotherapy system for lung SRT. A cylindrical collimator (0.3 cm φ) made of tungsten was introduced to collimate the X-ray beam. The system was simulated with BEAMnrc(EGS4) Monte Carlo code and various x-ray energy spectra were generated to investigate the dose distributions with our kilo-voltage SRT system. Experiments were performed to acquire the energy spectra of 100, 120 and 135 kVp (kilo-voltage peak) from CT measurements and those results were compared with the spectra obtained from Monte Carlo simulations. Verifications of percentage of dose depth (PDD) for 120 and 147.5 kVp were investigated in a water phantom with experiments and Monte Carlo simulations. Finally dose distributions of 120, 135, 147.5, 200, 250, 300, 350, 400, 500 kVp spectra were investigated with lung phantom and human lung. The Percentage of Depth Dose (PDD) in the water phantom calculated from the experimental and simulated spectra of 120 and 147.5 kVp show good agreement with each other. The PDD of 147.5 and 120 kVp spectra at 9 cm depth was approximately 10% and 9%, respectively. Dose distributions around the lung tumor in the phantom and human for all x-ray energies were almost uniform but in the case of the human lung absorptions of dose at ribs for the energy lower than 135 kVp was more than 35% and those absorptions for the energy spectra of 147.5 kVp and above was less than 30%. This absorption gradually decreases with increasing x-ray energies. Uniform dose distributions in the lung region of human and thorax phantom demonstrated the possibility of SRT system with medium energy X-ray. A detail performance of this system as a kilo-voltage conformal radiotherapy is under investigations. (author)

Accretion Properties of a Sample of Hard X-Ray (<60 keV) Selected Seyfert 1 Galaxies

Science.gov (United States)

Wang, J.; Mao, Y. F.; Wei, J. Y.

2009-02-01

We examine the accretion properties in a sample of 42 hard (3-60 keV) X-ray selected nearby broad-line active galactic nuclei (AGNs). The energy range in the sample is harder than that usually used in similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey, and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad Hβ emission line. The tight correlation between the hard X-ray (3-20 keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the Hβ emission line. In addition, all of these hard X-ray AGNs are biased toward luminous objects with a high Eddington ratio (mostly between 0.01 and 0.1) and a low column density (Simbol-X, and NeXT. Finally, the correlation between RFe (= optical Fe II/Hβ) and disk temperature as assessed by T vprop (L/L Edd)M -1 BH leads us to suggest that the strength of the Fe II emission is mainly determined by the shape of the ionizing spectrum.

A Micromegas-based low-background x-ray detector coupled to a slumped-glass telescope for axion research

CERN Document Server

Aznar, F; Christensen, F E; Dafni, T; Decker, T A; Ferrer-Ribas, E; Garcia, J A; Giomataris, I; Gracia, J G; Hailey, C J; Hill, R M; Iguaz, F J; Irastorza, I G; Jakobsen, A C; Luzon, G; Mirallas, H; Papaevangelou, T; Pivovaroff, M J; Ruz, J; Vafeiadis, T; Vogel, J K

2015-01-01

We report on the design, construction and operation of a low background x-ray detection line composed of a shielded Micromegas (micromesh gaseous structure) detector of the microbulk technique. The detector is made from radiopure materials and is placed at the focal point of a $\\sim$~5 cm diameter, 1.3 m focal-length, cone-approximation Wolter I x-ray telescope (XRT) comprised of thermally-formed (or "slumped") glass substrates deposited with multilayer coatings. The system has been conceived as a technological pathfinder for the future International Axion Observatory (IAXO), as it combines two of the techniques (optic and detector) proposed in the conceptual design of the project. It is innovative for two reasons: it is the first time an x-ray optic has been designed and fabricated specifically for axion research, and the first time a Micromegas detector has been operated with an x-ray optic. The line has been installed at one end of the CERN Axion Solar Telescope (CAST) magnet and is currently looking for s...

The Analysis of Symbols in The Death of A Salaesman by Arthur Miller

OpenAIRE

Ardani, Hanida Dwi

2011-01-01

Simbol adalah pemaknaan terhadap sesuatu dengan bentuk lain. Di dalam skripsi ini saya menganalisis simbol – simbol yang ditemukan dalam drama yang ditulis oleh Arthur Miller “ Death of a Salesman” . Dalam drama “ Death of a Salesman “ memiliki banyak simbol yang digunakan untuk mempertegas makna dari drama melalui teks yang ada. Simbol bisa berupa perhiasan “ diamond “ yang mempresentasikan keinginan. Kehidupan disimbolkan dalam bentuk hutan “ jungle “ yang mempresentasikan penuh misteri dan...

Effects of background radiation

International Nuclear Information System (INIS)

Knox, E.G.; Stewart, A.M.; Gilman, E.A.; Kneale, G.W.

1987-01-01

The primary objective of this investigation is to measure the relationship between exposure to different levels of background gamma radiation in different parts of the country, and different Relative Risks for leukaemias and cancers in children. The investigation is linked to an earlier analysis of the effects of prenatal medical x-rays upon leukaemia and cancer risk; the prior hypothesis on which the background-study was based, is derived from the earlier results. In a third analysis, the authors attempted to measure varying potency of medical x-rays delivered at different stages of gestation and the results supply a link between the other two estimates. (author)

Characterization of nanophase materials by x-ray diffraction and computer simulation

International Nuclear Information System (INIS)

Eastman, J.A.; Thompson, L.J.

1989-06-01

X-ray diffraction experiments on nanophase Pd have been performed with the primary goal of determining the nature of grain boundary structures in nanophase materials. A kinematical diffraction analysis has been developed to interpret x-ray θ--2θ data by comparing actual scans with scans produced by computer simulation. This simulation program has been used to explore the effects on diffracted intensity of a variety of microstructural and grain boundary structural parameters such as void concentration, grain size, grain boundary width, and changes in interplanar spacing and density in grain boundary regions. It has been found that a reasonable match to experimental data is produced by at least two model structures; in one, the material contains randomly positioned voids or vacancies, while in the other, the interplanar spacings in grain boundary regions are varied with respect to the spacings found in the grain interiors. 7 refs., 4 figs

Caliste 64, an innovative CdTe hard X-ray micro-camera

International Nuclear Information System (INIS)

Meuris, A.; Limousin, O.; Pinsard, F.; Le Mer, I.; Lugiez, F.; Gevin, O.; Delagnes, E.; Vassal, M.C.; Soufflet, F.; Bocage, R.

2008-01-01

A prototype 64 pixel miniature camera has been designed and tested for the Simbol-X hard X-ray observatory to be flown on the joint CNES-ASI space mission in 2014. This device is called Caliste 64. It is a high performance spectro-imager with event time-tagging capability, able to detect photons between 2 keV and 250 keV. Caliste 64 is the assembly of a 1 or 2 min thick CdTe detector mounted on top of a readout module. CdTe detectors equipped with Aluminum Schottky barrier contacts are used because of their very low dark current and excellent spectroscopic performance. Front-end electronics is a stack of four IDeF-X V1.1 ASICs, arranged perpendicular to the detection plane, to read out each pixel independently. The whole camera fits in a 10 * 10 * 20 mm 3 volume and is juxtaposable on its four sides. This allows the device to be used as an elementary unit in a larger array of Caliste 64 cameras. Noise performance resulted in an ENC better than 60 electrons rms in average. The first prototype camera is tested at -10 degrees C with a bias of -400 V. The spectrum summed across the 64 pixels results in a resolution of 697 eV FWHM at 13.9 keV and 808 eV FWFM at 59.54 keV. (authors)

Micro Hard-X Ray Camera: From Caliste 64 to Caliste 256

International Nuclear Information System (INIS)

Meuris, A.; Limousin, O.; Le Mer, I.; Pinsard, F.; Blondel, C.; Daly, F.; Lugiez, F.; Gevin, O.; Delagnes, E.; Chavassieux, M.; Vassal, M.C.; Bocage, R.; Soufflet, F.

2009-01-01

Caliste project aims at hybridizing 1 cm 2 Cd(Zn)Te detectors with low noise front-end electronics, in a single component standing in a 1 * 1 * 2 cm 3 volume. The micro-camera is a spectroscopic imager for X and gamma rays detection, with time-tagging capability. Hybridization consists in stacking full custom ASICs perpendicular to the detection surface. The first prototype Caliste 64 integrates a detector of 8 * 8 pixels of 1 mm pitch. Fabrication and characterizations of nine cameras units validate the design and the hybridization concept. Spectroscopic tests result in a mean energy resolution of ∼0.7 keV FWHM at 14 keV and ∼0.85 keV FWHM at 60 keV using 1 mm-thick Al Schottky CdTe detectors biased at -400 V and cooled down to 15 degrees C. The new prototype called Caliste 256 integrates 16 * 16 pixels of 580 m pitch in the same volume as Caliste 64. Electrical tests with the first sample fabricated without detector result in a mean equivalent noise charge of 64e - rms (9.6 μs, no leakage current). Caliste devices are 4-side buttable and can be used as elementary detection units of a large hard X-ray focal plane, as for the 64 cm 2 high energy detector of the Simbol-X astronomical space mission. (authors)

Validation of a novel basic virtual reality simulator, the LAP-X, for training basic laparoscopic skills.

Science.gov (United States)

Kawaguchi, Koji; Egi, Hiroyuki; Hattori, Minoru; Sawada, Hiroyuki; Suzuki, Takahisa; Ohdan, Hideki

2014-10-01

Virtual reality surgical simulators are becoming popular as a means of providing trainees with an opportunity to practice laparoscopic skills. The Lap-X (Epona Medical, Rotterdam, the Netherlands) is a novel VR simulator for training basic skills in laparoscopic surgery. The objective of this study was to validate the LAP-X laparoscopic virtual reality simulator by assessing the face and construct validity in order to determine whether the simulator is adequate for basic skills training. The face and content validity were evaluated using a structured questionnaire. To assess the construct validity, the participants, nine expert surgeons (median age: 40 (32-45)) (>100 laparoscopic procedures) and 11 novices performed three basic laparoscopic tasks using the Lap-X. The participants reported a high level of content validity. No significant differences were found between the expert surgeons and the novices (Ps > 0.246). The performance of the expert surgeons on the three tasks was significantly better than that of the novices in all parameters (Ps training device.

Analysis of the relative movement between mirrors and detectors for the next generation x-ray telescopes

Science.gov (United States)

Civitani, Marta

2009-08-01

Focusing X-ray telescopes with imaging capabilities, like SIMBOL-X, HEXISAT and IXO, are characterized by very long focal lengths, greater than 10m. The constraints posed by the launchers on the maximum dimensions of a payload, make necessary using alternatives to monolithic telescopes. One possibility is that the mirror and the detectors are carried by two separate spacecrafts that fly in formation. Another is placing the detector module on a bench that will be extended once in final orbit. In both the case the system will be subjected to deformation due the relative movement of the mirrors with respect to detectors. In one case the deformation will be due to the correction on the position and attitude of the detector spacecraft to maintain the formation with the mirror spacecraft, while in the other to oscillations of the detectors on the top of the bench. The aim of this work is to compare the behavior of the system in the two different configurations and to evaluate the performances of the on board metrology systems needed not to degrade the telescope angular resolution.

Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

Science.gov (United States)

Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

2015-04-01

In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

Energy Technology Data Exchange (ETDEWEB)

Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd., Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M.; Edwards-Gau, Gregory R. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

2015-04-28

In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

Development of background reduced Fresnel phase zone plate

International Nuclear Information System (INIS)

Tamari, Yohei; Azechi, Hiroshi

2004-01-01

In study of hot and dense plasma, a high spatial resolution (a few microns) x-ray imaging is very important to observe these plasmas. The Fresnel phase zone plate (FPZP) consists of alternately material and transparent circular annuli placed concentrically, which image x rays using diffraction x rays from all annuli. FPZP have imaged 4.7-4.77 keV x rays with 2.2 μm spatial resolution. However FPZP has a problem that background level is comparable to signal level. In subtraction of background, the error of 10% is caused. For the accurate background subtraction, we designed new FPZP, which consist of three β layers of a transparent zone and two material zones. The new design FPZP parameters (thickness of material zones, each zone width) have been optimized, and in that optimum design signal-to-background ratio is 4 times better than conventional two layers FPZP

Theoretical simulation of soft x-rays for recombining pump

International Nuclear Information System (INIS)

Peng Huimin; Zhang Guoping; Sheng Jiatian

1990-05-01

The theoretical study and computational simulation of soft X-ray laser produced by the recombination of highly ionized plasma are given. An one-dimensional non LTE radiative hydrodynamic code JB-19 is used for simulating the process of soft X-ray laser produced by the recombination. The incident laser light is focused linearly onto the thin carbon fibre. In the duration of incident laser pulse a highly ionized plasma is generated. After the incident laser has been ended the plasma adiabatically expands and rapidly cools down. During the time of three-body recombination and cascading transition, the population inversion between n = 3 and n = 2 is produced and transition gain is obtained. The analysis and evolution is presented, and factors effected on the gain are also discussed. The calculated results have been compared with the experimental data of RAL. It is found that some were in good agreement with them but some are not. Under the limitation of laser energy, the gain is inversely proportional to the wave-length and pulse width of incident laser. For obtaining high gain it is necessary to have double frequency and to shorten the pulse width of Nd-glass laser. Finally the preliminary results about H-like F ion are also given

Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

Energy Technology Data Exchange (ETDEWEB)

Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan, E-mail: yangjing_928@126.com

2017-06-15

Highlights: • A micro X-ray fluorescence setup based on an ellipsoidal capillary was presented. • The optimal parameters of ellipsoidal capillary were designed. • The 2D mapping image of biological sample was obtained. - Abstract: A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

Science.gov (United States)

Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

2009-06-01

Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries

Science.gov (United States)

Grandin, Robert J.; Young, Gavin; Holland, Stephen D.; Krishnamurthy, Adarsh

2018-04-01

Interactive x-ray simulations of complex computer-aided design (CAD) models can provide valuable insights for better interpretation of the defect signatures such as porosity from x-ray CT images. Generating the depth map along a particular direction for the given CAD geometry is the most compute-intensive step in x-ray simulations. We have developed a GPU-accelerated method for real-time generation of depth maps of complex CAD geometries. We preprocess complex components designed using commercial CAD systems using a custom CAD module and convert them into a fine user-defined surface tessellation. Our CAD module can be used by different simulators as well as handle complex geometries, including those that arise from complex castings and composite structures. We then make use of a parallel algorithm that runs on a graphics processing unit (GPU) to convert the finely-tessellated CAD model to a voxelized representation. The voxelized representation can enable heterogeneous modeling of the volume enclosed by the CAD model by assigning heterogeneous material properties in specific regions. The depth maps are generated from this voxelized representation with the help of a GPU-accelerated ray-casting algorithm. The GPU-accelerated ray-casting method enables interactive (> 60 frames-per-second) generation of the depth maps of complex CAD geometries. This enables arbitrarily rotation and slicing of the CAD model, leading to better interpretation of the x-ray images by the user. In addition, the depth maps can be used to aid directly in CT reconstruction algorithms.

Alamethicin in lipid bilayers: combined use of X-ray scattering and MD simulations.

Science.gov (United States)

Pan, Jianjun; Tieleman, D Peter; Nagle, John F; Kucerka, Norbert; Tristram-Nagle, Stephanie

2009-06-01

We study fully hydrated bilayers of two di-monounsaturated phospholipids diC18:1PC (DOPC) and diC22:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering and molecular dynamics simulations to determine the orientation of alamethicin in model lipids. Comparison of the experimental and simulated form factors shows that Alm helices are inserted transmembrane at high humidity and high concentrations, in agreement with earlier results. The X-ray scattering data and the MD simulations agree that membrane thickness changes very little up to 1/10 Alm/DOPC. In contrast, the X-ray data indicate that the thicker diC22:1PC membrane thins with added Alm, a total decrease in thickness of 4 A at 1/10 Alm/diC22:1PC. The different effect of Alm on the thickness changes of the two bilayers is consistent with Alm having a hydrophobic thickness close to the hydrophobic thickness of 27 A for DOPC; Alm is then mismatched with the 7 A thicker diC22:1PC bilayer. The X-ray data indicate that Alm decreases the bending modulus (K(C)) by a factor of approximately 2 in DOPC and a factor of approximately 10 in diC22:1PC membranes (P/L approximately 1/10). The van der Waals and fluctuational interactions between bilayers are also evaluated through determination of the anisotropic B compressibility modulus.

PARTICLE ACCELERATION AND THE ORIGIN OF X-RAY FLARES IN GRMHD SIMULATIONS OF SGR A*

Energy Technology Data Exchange (ETDEWEB)

Ball, David; Özel, Feryal; Psaltis, Dimitrios; Chan, Chi-kwan [Steward Observatory and Department of Astronomy, University of Arizona (United States)

2016-07-20

Significant X-ray variability and flaring has been observed from Sgr A* but is poorly understood from a theoretical standpoint. We perform general relativistic magnetohydrodynamic simulations that take into account a population of non-thermal electrons with energy distributions and injection rates that are motivated by PIC simulations of magnetic reconnection. We explore the effects of including these non-thermal electrons on the predicted broadband variability of Sgr A* and find that X-ray variability is a generic result of localizing non-thermal electrons to highly magnetized regions, where particles are likely to be accelerated via magnetic reconnection. The proximity of these high-field regions to the event horizon forms a natural connection between IR and X-ray variability and accounts for the rapid timescales associated with the X-ray flares. The qualitative nature of this variability is consistent with observations, producing X-ray flares that are always coincident with IR flares, but not vice versa, i.e., there are a number of IR flares without X-ray counterparts.

Translation of PLC Programs to x86 for Simulation and Verification

CERN Document Server

Sallai, Gyula

2017-01-01

PLC programs are written in special languages, variants of the languages defined in the IEC 61131 standard. These programs cannot be directly executed on personal computers (on x86 architecture). To perform simulation of the PLC program or diagnostics during development, either a real PLC or a PLC simulator has to be used. However, these solutions are often inflexible and they do not provide appropriate performance. By generating x86-representations (semantically equivalent programs which can be executed on PCs, e.g. written in C, C++ or Java) of the PLC programs, some of these challenges could be met. PLCverif is a PLC program verification tool developed at CERN which includes a parser for Siemens PLC programs. In this work, we describe a code generator based on this parser of PLCverif. This work explores the possibilities and challenges of generating programs in widely-used general purpose languages from PLC programs, and provides a proof-of-concept code generation implementation. The presented solution dem...

High energy x-radiographic assessment of conditioned intermediate level waste blocks

International Nuclear Information System (INIS)

Lewcock, A.I.; Burch, S.F.; Reynolds, W.N.; Pullen, D.A.W.; Smith, D.

1985-07-01

This report describes an effective technique for examining the quality of the solidification matrix material in a 500 litre waste drum, testing for homogeneity and major cracks and the confirmation of set. A high energy x-ray source, (an 8 MeV Linac) and a special x-ray TV system, were used to examine several different types of solidified waste form, with and without background radiation, simulated by the use of an uncollimated radiographic isotope. The system as tested showed no discernable image degradation when the isotope was positioned to give a representative background dose as experienced with active ILW monoliths. (author)

Quantitative analysis without standards using local peak-to-background ratios with the energy dispersive X-ray microanalyzer EDR-184

International Nuclear Information System (INIS)

Eggert, F.; Heckel, J.

1986-01-01

The method realized in program QMA-184 of the energy dispersive X-Ray-Microanalyzer EDR-184 for quantitative spectra analyzing of bulk materials by using local peak-to-background ratios is described in detail. The authors demonstrate efficiency and limitations of the used method by discussion of experimental results. (author)

Computer simulation for synchrotron radiation based X-ray fluorescent microtomography

International Nuclear Information System (INIS)

Deng Biao; Yu Xiaohan; Xu Hongjie

2007-01-01

Synchrotron radiation based fluorescent microtomography (SR-XFMT) is a nondestructive technique for detecting elemental composition and distribution inside a specimen with high spatial resolution and sensitivity, and will be an optional experimental technique at SSRF hard X-ray micro-focusing beamline now under construction. In this paper, the principles and developments of SR-XFMT are briefly introduced. Computer simulation of SR-XFMT experiment is performed. The image of the simulated sample is reconstructed using Filtered Back Projection (FBP), Algebraic Reconstruction Techniques (ART) and modified FBP with absorption correction. The qualities of the reconstructed images are analyzed and compared. The validity of these reconstruction techniques is discussed. (authors)

A computer code to simulate X-ray imaging techniques

International Nuclear Information System (INIS)

Duvauchelle, Philippe; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

2000-01-01

A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests

A computer code to simulate X-ray imaging techniques

Energy Technology Data Exchange (ETDEWEB)

Duvauchelle, Philippe E-mail: philippe.duvauchelle@insa-lyon.fr; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

2000-09-01

A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests.

Background study for the pn-CCD detector of CERN Axion Solar Telescope

CERN Document Server

Cebrián, S; Kuster, M.; Beltran, B.; Gomez, H.; Hartmann, R.; Irastorza, I. G.; Kotthaus, R.; Luzon, G.; Morales, J.; Ruz, J.; Struder, L.; Villar, J. A.

2007-01-01

The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into photons with energies up to around 10 keV via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) prototype magnet. A backside illuminated pn-CCD detector in conjunction with an X-ray mirror optics is one of the three detectors used in CAST to register the expected photon signal. Since this signal is very rare and different background components (environmental gamma radiation, cosmic rays, intrinsic radioactive impurities in the set-up, ...) entangle it, a detailed study of the detector background has been undertaken with the aim to understand and further reduce the background level of the detector. The analysis is based on measured data taken during the Phase I of CAST and on Monte Carlo simulations of different background components. This study will show that the observed background level (at a rate of (8.00+-0.07)10^-5 counts/cm^2/s/keV between 1 and 7 keV) s...

Geant4 simulation of the response of phosphor screens for X-ray imaging

International Nuclear Information System (INIS)

Pistrui-Maximean, S.A.; Freud, N.; Letang, J.M.; Koch, A.; Munier, B.; Walenta, A.H.; Montarou, G.; Babot, D.

2006-01-01

In order to predict and optimize the response of phosphor screens, it is important to understand the role played by the different physical processes inside the scintillator layer. A simulation model based on the Monte Carlo code Geant4 was developed to determine the Modulation Transfer Function (MTF) of phosphor screens for energies used in X-ray medical imaging and nondestructive testing applications. The visualization of the dose distribution inside the phosphor layer gives an insight into how the MTF is progressively degraded by X-ray and electron transport. The simulation model allows to study the influence of physical and technological parameters on the detector performances, as well as to design and optimize new detector configurations. Preliminary MTF measurements have been carried out and agreement with experimental data has been found in the case of a commercial screen (Kodak Lanex Fine) at an X-ray tube potential of 100 kV. Further validation with other screens (transparent or granular) at different energies is under way

Geant4 simulation of the response of phosphor screens for X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Pistrui-Maximean, S.A. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France)]. E-mail: simona.pistrui@insa-lyon.fr; Freud, N. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France); Letang, J.M. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France); Koch, A. [Thales Electron Devices, 38430 Moirans (France); Munier, B. [Thales Electron Devices, 38430 Moirans (France); Walenta, A.H. [Department of Detectors and Electronics, FB Physik, University of Siegen, 57068 Siegen (Germany); Montarou, G. [Corpuscular Physics Laboratory, Blaise Pascal University, 63177 Aubiere Cedex (France); Babot, D. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France)

2006-07-01

In order to predict and optimize the response of phosphor screens, it is important to understand the role played by the different physical processes inside the scintillator layer. A simulation model based on the Monte Carlo code Geant4 was developed to determine the Modulation Transfer Function (MTF) of phosphor screens for energies used in X-ray medical imaging and nondestructive testing applications. The visualization of the dose distribution inside the phosphor layer gives an insight into how the MTF is progressively degraded by X-ray and electron transport. The simulation model allows to study the influence of physical and technological parameters on the detector performances, as well as to design and optimize new detector configurations. Preliminary MTF measurements have been carried out and agreement with experimental data has been found in the case of a commercial screen (Kodak Lanex Fine) at an X-ray tube potential of 100 kV. Further validation with other screens (transparent or granular) at different energies is under way.

Low Background Micromegas in CAST

CERN Document Server

Garza, J.G.; Aznar, F.; Calvet, D.; Castel, J.F.; Christensen, F.E.; Dafni, T.; Davenport, M.; Decker, T.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Giomataris, I.; Hill, R.M.; Iguaz, F.J.; Irastorza, I.G.; Jakobsen, A.C.; Jourde, D.; Mirallas, H.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M.J.; Ruz, J.; Tomás, A.; Vafeiadis, T.; Vogel, J.K.

2015-11-16

Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as ...

Construction of a catalog of X-ray spectra for mammography simulations

International Nuclear Information System (INIS)

Santos, L.C.S.; Vieira, J.W.

2017-01-01

Computational Exposure Models (MCEs) allow the simulation of the interaction of radiation with matter by means of Monte Carlo (MC) techniques. Generally, MCEs are composed of phantom, simulator algorithms of radioactive sources and an MC code to simulate the transport, interaction of the radiation with matter and to evaluate the energy deposited in regions of interest. To compose an MCE for simulations in mammography, the construction of a catalog of X-ray spectra was started, based on the catalog model constructed and using until then in MCEs by the Group of Research in Numerical Dosimetry and by the Group of Research in Computational Dosimetry & Embedded Systems (both referenced in this work as GDN). Potential of 25 kV and 35 kV and used target / filter were applied to the tube: Mo / Mo. The file containing the spectra was read correctly by EGSnrc

Systematic design and three-dimensional simulation of X-ray FEL oscillator for Shanghai Coherent Light Facility

Science.gov (United States)

Li, Kai; Deng, Haixiao

2018-07-01

The Shanghai Coherent Light Facility (SCLF) is a quasi-continuous wave hard X-ray free electron laser facility, which is currently under construction. Due to the high repetition rate and high-quality electron beams, it is straightforward to consider X-ray free electron laser oscillator (XFELO) operation for the SCLF. In this paper, the main processes for XFELO design, and parameter optimization of the undulator, X-ray cavity, and electron beam are described. A three-dimensional X-ray crystal Bragg diffraction code, named BRIGHT, was introduced for the first time, which can be combined with the GENESIS and OPC codes for the numerical simulations of the XFELO. The performance of the XFELO of the SCLF is investigated and optimized by theoretical analysis and numerical simulation.

Crack propagation and arrest simulation of X90 gas pipe

International Nuclear Information System (INIS)

Yang, Fengping; Huo, Chunyong; Luo, Jinheng; Li, He; Li, Yang

2017-01-01

To determine whether X90 steel pipe has enough crack arrest toughness or not, a damage model was suggested as crack arrest criterion with material parameters of plastic uniform percentage elongation and damage strain energy per volume. Fracture characteristic length which characterizes fracture zone size was suggested to be the largest mesh size on expected cracking path. Plastic uniform percentage elongation, damage strain energy per volume and fracture characteristic length of X90 were obtained by five kinds of tensile tests. Based on this criterion, a length of 24 m, Φ1219 × 16.3 mm pipe segment model with 12 MPa internal gas pressure was built and computed with fluid-structure coupling method in ABAQUS. Ideal gas state equation was used to describe lean gas behavior. Euler grid was used to mesh gas zone inside the pipe while Lagrangian shell element was used to mesh pipe. Crack propagation speed and gas decompression speed were got after computation. The result shows that, when plastic uniform percentage elongation is equal to 0.054 and damage strain energy per volume is equal to 0.64 J/mm"3, crack propagation speed is less than gas decompression speed, which means the simulated X90 gas pipe with 12 MPa internal pressure can arrest cracking itself. - Highlights: • A damage model was suggested as crack arrest criterion. • Plastic uniform elongation and damage strain energy density are material parameters. • Fracture characteristic length is suggested to be largest mesh size in cracking path. • Crack propagating simulation with coupling of pipe and gas was realized in ABAQUS. • A Chinese X90 steel pipe with 12 MPa internal pressure can arrest cracking itself.

Design of a tritium gas cell for beta-ray induced X-ray spectrometry using Monte Carlo simulation

Energy Technology Data Exchange (ETDEWEB)

Hara, Masanori, E-mail: masahara@ctg.u-toyama.ac.jp [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Abe, Shinsuke; Matsuyama, Masao [Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, 3190 Gofuku, Toyama City, Toyama 930-8555 (Japan); Aso, Tsukasa [Electronics and Computer Engineering, National Institute of Technology, Toyama College, 1-2 Ebie-neriya, Imizu City, Toyama 933-0293 (Japan); Tatenuma, Katsuyoshi; Kawakami, Tomohiko; Ito, Takeshi [KAKEN Company Limited, 1044 Horimachi, Mito City, Ibaraki 310-0903 (Japan)

2017-06-15

Highlights: • Beta-ray induced X-ray spectrometry (BIXS) is a method for tritium gas analysis. • Gas cell for BIXS was designed by Monte Carlo simulations. • The optimum thickness of the gold layer on a beryllium window was around 150 nm. • This simulation model considered the self-absorption with increasing the cell length. - Abstract: One of the methods used for tritium gas analysis is beta-ray induced X-ray spectrometry (BIXS). Gas cell design is important in this method. The structure of the gas cell for BIXS was optimized by Monte Carlo simulation of beta-ray induced X-ray spectra in various window geometries using the Geant4 tool kit (version 10.01.p02). The simulated spectrum from tritium decay fitted the observed one, and the simulation model was used to obtain the cell parameters for BIXS. The optimum thickness of the gold layer on a beryllium window was around 150 nm. This simulation model also considered the relationship between self-absorption by hydrogen gas and the cell length. Self-absorption increased with increasing cell length and the relationship between the sample pressure and cell length was formulated.

Monte-Carlo simulation of primary electrons in the matter for the generation of x-rays

International Nuclear Information System (INIS)

Bendjama, H.; Laib, Y.; Allag, A.; Drai, R.

2006-01-01

The x-rays imagining chains components from the source to the detector, rest on the first part of simulation to the energy production of x-rays emission (source), which suggest us to identified the losses energies result from interaction between the fast electrons and the particles of metal : the energies losses due to 'collisional losses' (ionization, excitation) and radiative losses. For the medium and the primary electron energy which interests us, the electrons slowing down in the matter results primarily from the inelastic collisions; whose interest is to have to simulate the x-rays characteristic spectrum. We used a Monte-Carlo method to simulate the energy loss and the transport of primary electrons. This type of method requires only the knowledge of the cross sections attached to the description of all the elementary events. In this work, we adopted the differential cross section of Mott and the total cross section of inner-shell ionization according to the formulation of Gryzinski, to simulate the energy loss and the transport of primary electrons respectively. The simulation allows to follow the electrons until their energy reaches the atomic ionization potential of the irradiated matter. The differential cross section of Mott gives us a very good representation of the pace of the distribution of the energy losses. The transport of primary electron is approximately reproduced

A Study of Background Conditions for Sphinx—The Satellite-Borne Gamma-Ray Burst Polarimeter

Directory of Open Access Journals (Sweden)

Fei Xie

2018-04-01

Full Text Available SPHiNX is a proposed satellite-borne gamma-ray burst polarimeter operating in the energy range 50–500 keV. The mission aims to probe the fundamental mechanism responsible for gamma-ray burst prompt emission through polarisation measurements. Optimising the signal-to-background ratio for SPHiNX is an important task during the design phase. The Geant4 Monte Carlo toolkit is used in this work. From the simulation, the total background outside the South Atlantic Anomaly (SAA is about 323 counts/s, which is dominated by the cosmic X-ray background and albedo gamma rays, which contribute ∼60% and ∼35% of the total background, respectively. The background from albedo neutrons and primary and secondary cosmic rays is negligible. The delayed background induced by the SAA-trapped protons is about 190 counts/s when SPHiNX operates in orbit for one year. The resulting total background level of ∼513 counts/s allows the polarisation of ∼50 GRBs with minimum detectable polarisation less than 30% to be determined during the two-year mission lifetime.

Low Background Micromegas in CAST

DEFF Research Database (Denmark)

Garza, J G; Aune, S.; Aznar, F.

2014-01-01

Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micr...

Some issues and subtleties in numerical simulation of X-ray FEL's

International Nuclear Information System (INIS)

Fawley, William M.

2002-01-01

Part of the overall design effort for x-ray FEL's such as the LCLS and TESLA projects has involved extensive use of particle simulation codes to predict their output performance and underlying sensitivity to various input parameters (e.g. electron beam emittance). This paper discusses some of the numerical issues that must be addressed by simulation codes in this regime. We first give a brief overview of the standard approximations and simulation methods adopted by time-dependent(i.e. polychromatic) codes such as GINGER, GENESIS, and FAST3D, including the effects of temporal discretization and the resultant limited spectral bandpass,and then discuss the accuracies and inaccuracies of these codes in predicting incoherent spontaneous emission (i.e. the extremely low gain regime)

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

International Nuclear Information System (INIS)

Gevin, O.; Baron, P.; Coppolani, X.; Delagnes, E.; Lugiez, F.; Daly, F.; Limousin, O.; Meuris, A.; Pinsard, F.; Renaud, D.

2009-01-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e - rms) and to its radiation hardened design (Single Event Latch-up Linear Energy Transfer threshold of 56 MeV.cm 2 .mg -1 ), the chip is well suited for soft X-rays energy discrimination and high energy resolution, 'space proof', hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7e - /pF obtained with a 6 μs peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky mono-pixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission. (authors)

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

Science.gov (United States)

Gevin, Olivier; Baron, Pascal; Coppolani, Xavier; Daly, FranÇois; Delagnes, Eric; Limousin, Olivier; Lugiez, Francis; Meuris, Aline; Pinsard, FrÉdÉric; Renaud, Diana

2009-08-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e- rms) and to its radiation hardened design (Single Event Latchup Linear Energy Transfer threshold of 56 MeV.cm2.mg-1), the chip is well suited for soft X-rays energy discrimination and high energy resolution, ldquospace proof,rdquo hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7 e-/pF obtained with a 6 mus peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky monopixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission.

Virtual Deformation Control of the X-56A Model with Simulated Fiber Optic Sensors

Science.gov (United States)

Suh, Peter M.; Chin, Alexander W.; Mavris, Dimitri N.

2014-01-01

A robust control law design methodology is presented to stabilize the X-56A model and command its wing shape. The X-56A was purposely designed to experience flutter modes in its flight envelope. The methodology introduces three phases: the controller design phase, the modal filter design phase, and the reference signal design phase. A mu-optimal controller is designed and made robust to speed and parameter variations. A conversion technique is presented for generating sensor strain modes from sensor deformation mode shapes. The sensor modes are utilized for modal filtering and simulating fiber optic sensors for feedback to the controller. To generate appropriate virtual deformation reference signals, rigid-body corrections are introduced to the deformation mode shapes. After successful completion of the phases, virtual deformation control is demonstrated. The wing is deformed and it is shown that angle-ofattack changes occur which could potentially be used to an advantage. The X-56A program must demonstrate active flutter suppression. It is shown that the virtual deformation controller can achieve active flutter suppression on the X-56A simulation model.

Evaluation of the use of computed tomography versus conventional orthogonal X-ray simulation in the treatment of rectal cancer

International Nuclear Information System (INIS)

Darben, P.; Lim-Joon, D.; Chao, M.; Gibbs, P.; Tjandra, J.; Jones, I.T.

2005-01-01

The aim of this study is to compare and contrast the treatment fields designed using CT versus conventional orthogonal X-ray simulation in the treatment of patients with rectal cancer given preoperative chemotherapy and radiotherapy. Nine patients participated in this study. The coverage of treatment fields, the volume of treatment fields, and the position of the anorectal junction in relation to the inferior border of the obturator foramen as the delineator of the pelvic floor were evaluated in each patient using CT and conventional orthogonal X-ray simulation. The results demonstrated undercoverage of the anterior border of the lateral fields of up to 2.5 cm in seven of nine patients when conventional orthogonal X-ray simulation was compared to CT simulation. In addition, the inferior border of the obturator foramen proved to be a poor delineator of the pelvic floor with the anorectal junction situated up to 2 cm superiorly in seven of nine patients. In conclusion, CT simulation is superior to conventional orthogonal X-ray simulation when designing treatment fields for patients with rectal cancer Copyright (2005) Blackwell Publishing Asia Pty Ltd

X-ray and neutron diffraction and molecular dynamics simulation of molten lithium and rubidium nitrates

International Nuclear Information System (INIS)

Yamaguchi, Toshio; Okada, Isao; Ohtaki, Hitoshi; Mikami, Masuhiro; Kawamura, Kazutaka

1986-01-01

Molecular dynamics simulations have been performed for lithium and rubidium nitrate melts at 550 and 600K, respectively, together with X-ray and neutron diffraction experiments. Simple Coulomb pair potentials with Born-type repulsions have been adopted in the simulations with a rigid body model for the nitrate ion. Structure functions derived from the X-ray and neutron experiments are well reproduced by the simulations, from which the three-dimensional cation distribution around the nitrate ion has been revealed. The self-diffusion coefficients, the velocity autocorrelation functions and the self-exchange velocities of lithium, rubidium and nitrate ions have been calculated. Anisotropic motion of nitrate ions has been found and is discussed on the basis of the structure of the melts. (author)

Comparison of simulated light sensitometer and x-ray sensitometer for screen-film system in medical radiology

International Nuclear Information System (INIS)

Tsuyama, Yasuko; Yamamoto, Yoshinori.

1983-01-01

Sensitometric techniques are used for determining the characteristic curve in medical imaging. In this study intensity-scale (inverse square law, simulated light) methods are used in the determination of radiographic screen-film system characteristic curve. Films which were exposed to simulated light and x-ray were processed in the same automatic processor simultaneously. These curves were overlapped at Net density of 1.0 to compare the curve shapes. The results show there is a good correlation between the density of x-ray sensitometry and that of simulated light sensitometry. The differences of density are within +- 0.12 (+- 10 % log exposure). This applies to both blue sensitive and green sensitive systems. (author)

Makna Simbolik Tradisi Rebo Kasan

Directory of Open Access Journals (Sweden)

Rian Rahmawati

2017-07-01

Full Text Available Penelitian ini dilatarbelakangi oleh ketertarikan peneliti terkait makna dibalik penggunaan simbol tertentu pada tradisi Rebo Kasan yang sampai sekarang masih dipertahankan oleh beberapa kelompok masyarakat di Kabupaten Garut. Hal ini penting mengingat tradisi Rebo Kasan ini merupakan rangkaian sejarah masa lalu yang mengandung nilai-nilai moral maupun keagamaan didalamnya. Tujuan penelitian ini adalah untuk menemukan dan menjelaskan lebih dalam mengenai makna denotasi, konotasi dan mitos pada simbol-simbol Rebo Kasan di Kabupaten Garut. Metode penelitian yang digunakan dalam penelitian ini adalah metode analisis Semiotik Roland Barthes, yaitu studi yang mengkaji makna suatu tanda baik itu makna denotasi, konotasi dan mitos, dengan pendekatan kualitatif, penelitian ini dapat mengungkap makna denotasi, konotasi dan mitos pada simbol-simbol yang digunakan dalam tradisi Rebo Kasan di Kabupaten Garut. Sedangkan teknik pengumpulan data yang digunakan pada penelitian ini adalah observasi partisipan, wawancara mendalam, studi kepustakaan. Subjek pada penelitian ini adalah jamuan yang dihidangkan pada perayaan tradisi tersebut serta pengambilan informan dengan menggunakan purposive sampling. Jumlah informan dalam penelitian ini adalah sebanyak 5 orang. Hasil penelitian menunjukkan bahwa dalam tradisi Rebo Kasan di Kabupaten Garut memiliki makna denotasi, konotasi dan mitos. Adapun yang merupakan simbol tradisi tersebut adalah, air putih, Dupi, Leupeut dan Bugis yang merupakan makanan khas dari daerah tersebut. Makna tradisi dari Rebo Kasan itu sendiri adalah berbagi atau bersedekah dengan tujuan menolak marabahaya yaitu dengan jamuan berupa makanan yang dimaknai dengan makna tertentu yaitu diantaranya, air putih merupakan simbol kesucian, Dupi sebagai simbol penolakan, Leupeut sebagai simbol mempersatukan, dan Bugis sebagai simbol keyakinan.

Magnetocaloric properties in La{sub 1−x}Ca{sub x}MnO{sub 3} thin films: Monte Carlo simulations

Energy Technology Data Exchange (ETDEWEB)

Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co; Ramos-Rivera, L.; Londoño-Navarro, J.

2014-02-15

The magnetocaloric effect (MCE) of La{sub 1−x}Ca{sub x}MnO{sub 3} was analyzed when varying the stoichiometry (x=0.2, 0.33, 0.4 and 0.5) and the external applied magnetic field. Simulations were carried out using the Monte Carlo method having a configuration ascribed by the set S{sub z} of all-site spin projections, under the Metropolis algorithm. La{sub 1−x}Ca{sub x}MnO{sub 3} is characterized for three types of magnetic ions corresponding to Mn{sup 4+} (S=3/2), which are bonded to Ca{sup 2+}, and Mn{sup 3+}(e{sub g}) and Mn{sup 3+}(e{sub g′}, S=2), which are both bonded to La{sup 3+}. Different interactions must be considered depending on the type of interacting ions. The entropy change ΔS in an isothermal process as well as the temperature change ΔT in an adiabatic process was determined with this model. Both ΔS and ΔT show stoichiometry-dependent maximums near the paramagnetic–ferromagnetic transition temperature (T{sub C}), confirming the order–disorder change at this temperature. The strong dependence in La{sub 1−x}Ca{sub x}MnO{sub 3} of the MCE on the stoichiometry and the external magnetic field makes this phenomenon important for different technological applications, particularly in refrigeration. - Highlights: • Thermal behavior of entropy, susceptibility and isothermal entropy change is studied. • ΔS and ΔT present a transition at the critical temperature depending on the stoichiometry. • Semi-classical Heisenberg Hamiltonian allows simulation of magnetocaloric effect in LCMO. • External magnetic field produces changes in ΔS and ΔT observed in the shifting of T{sub C}.

Statistical simulations of the dust foreground to cosmic microwave background polarization

Science.gov (United States)

Vansyngel, F.; Boulanger, F.; Ghosh, T.; Wandelt, B.; Aumont, J.; Bracco, A.; Levrier, F.; Martin, P. G.; Montier, L.

2017-07-01

The characterization of the dust polarization foreground to the cosmic microwave background (CMB) is a necessary step toward the detection of the B-mode signal associated with primordial gravitational waves. We present a method to simulate maps of polarized dust emission on the sphere that is similar to the approach used for CMB anisotropies. This method builds on the understanding of Galactic polarization stemming from the analysis of Planck data. It relates the dust polarization sky to the structure of the Galactic magnetic field and its coupling with interstellar matter and turbulence. The Galactic magnetic field is modeled as a superposition of a mean uniform field and a Gaussian random (turbulent) component with a power-law power spectrum of exponent αM. The integration along the line of sight carried out to compute Stokes maps is approximated by a sum over a small number of emitting layers with different realizations of the random component of the magnetic field. The model parameters are constrained to fit the power spectra of dust polarization EE, BB, and TE measured using Planck data. We find that the slopes of the E and B power spectra of dust polarization are matched for αM = -2.5, an exponent close to that measured for total dust intensity but larger than the Kolmogorov exponent - 11/3. The model allows us to compute multiple realizations of the Stokes Q and U maps for different realizations of the random component of the magnetic field, and to quantify the variance of dust polarization spectra for any given sky area outside of the Galactic plane. The simulations reproduce the scaling relation between the dust polarization power and the mean total dust intensity including the observed dispersion around the mean relation. We also propose a method to carry out multifrequency simulations, including the decorrelation measured recently by Planck, using a given covariance matrix of the polarization maps. These simulations are well suited to optimize

WavePropaGator: interactive framework for X-ray free-electron laser optics design and simulations.

Science.gov (United States)

Samoylova, Liubov; Buzmakov, Alexey; Chubar, Oleg; Sinn, Harald

2016-08-01

This article describes the WavePropaGator ( WPG ) package, a new interactive software framework for coherent and partially coherent X-ray wavefront propagation simulations. The package has been developed at European XFEL for users at the existing and emerging free-electron laser (FEL) facilities, as well as at the third-generation synchrotron sources and future diffraction-limited storage rings. The WPG addresses the needs of beamline scientists and user groups to facilitate the design, optimization and improvement of X-ray optics to meet their experimental requirements. The package uses the Synchrotron Radiation Workshop ( SRW ) C/C++ library and its Python binding for numerical wavefront propagation simulations. The framework runs reliably under Linux, Microsoft Windows 7 and Apple Mac OS X and is distributed under an open-source license. The available tools allow for varying source parameters and optics layouts and visualizing the results interactively. The wavefront history structure can be used for tracking changes in every particular wavefront during propagation. The batch propagation mode enables processing of multiple wavefronts in workflow mode. The paper presents a general description of the package and gives some recent application examples, including modeling of full X-ray FEL beamlines and start-to-end simulation of experiments.

Background and Pickup Ion Velocity Distribution Dynamics in Titan's Plasma Environment: 3D Hybrid Simulation and Comparison with CAPS T9 Observations

Science.gov (United States)

Lipatov, A. S.; Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

2011-01-01

In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions H(+); H2(+), CH4(+) and N2(+) is stronger than in the previous simulations when O+ ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfve n wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.

Effects of Small Oscillations on the Effective Area

International Nuclear Information System (INIS)

Cotroneo, V.; Conconi, P.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Cusumano, G.

2009-01-01

We analyze the effective area of the Simbol-X mirrors as a function of the off-axis angle for small oscillations. A reduction is expected due to: 1) geometrical effects, because some of the photons miss the secondary mirror surface; 2) reflectivity effects, caused by the variation of the coating reflectivity with the incidence angle. The former are related to the length of the two mirror surfaces, and can be reduced by making the secondary mirror longer. The second ones are energy-dependent, and strongly related to the characteristics of the reflecting coating. These effects are analyzed by means of ray-tracing simulations in order to optimize the mirror and coating design, aiming to improve the effective area stability.

Effects of Small Oscillations on the Effective Area

Science.gov (United States)

Cotroneo, V.; Conconi, P.; Cusumano, G.; Pareschi, G.; Spiga, D.; Tagliaferri, G.

2009-05-01

We analyze the effective area of the Simbol-X mirrors as a function of the off-axis angle for small oscillations. A reduction is expected due to: 1) geometrical effects, because some of the photons miss the secondary mirror surface; 2) reflectivity effects, caused by the variation of the coating reflectivity with the incidence angle. The former are related to the length of the two mirror surfaces, and can be reduced by making the secondary mirror longer. The second ones are energy-dependent, and strongly related to the characteristics of the reflecting coating. These effects are analyzed by means of ray-tracing simulations in order to optimize the mirror and coating design, aiming to improve the effective area stability.

Simulating X-ray bursts during a transient accretion event

Science.gov (United States)

Johnston, Zac; Heger, Alexander; Galloway, Duncan K.

2018-06-01

Modelling of thermonuclear X-ray bursts on accreting neutron stars has to date focused on stable accretion rates. However, bursts are also observed during episodes of transient accretion. During such events, the accretion rate can evolve significantly between bursts, and this regime provides a unique test for burst models. The accretion-powered millisecond pulsar SAX J1808.4-3658 exhibits accretion outbursts every 2-3 yr. During the well-sampled month-long outburst of 2002 October, four helium-rich X-ray bursts were observed. Using this event as a test case, we present the first multizone simulations of X-ray bursts under a time-dependent accretion rate. We investigate the effect of using a time-dependent accretion rate in comparison to constant, averaged rates. Initial results suggest that using a constant, average accretion rate between bursts may underestimate the recurrence time when the accretion rate is decreasing, and overestimate it when the accretion rate is increasing. Our model, with an accreted hydrogen fraction of X = 0.44 and a CNO metallicity of ZCNO = 0.02, reproduces the observed burst arrival times and fluences with root mean square (rms) errors of 2.8 h, and 0.11× 10^{-6} erg cm^{-2}, respectively. Our results support previous modelling that predicted two unobserved bursts and indicate that additional bursts were also missed by observations.

Simulation of TanDEM-X interferograms for urban change detection

Science.gov (United States)

Welte, Amelie; Hammer, Horst; Thiele, Antje; Hinz, Stefan

2017-10-01

Damage detection after natural disasters is one of the remote sensing tasks in which Synthetic Aperture Radar (SAR) sensors play an important role. Since SAR is an active sensor, it can record images at all times of day and in all weather conditions, making it ideally suited for this task. While with the newer generation of SAR satellites such as TerraSAR-X or COSMOSkyMed amplitude change detection has become possible even for urban areas, interferometric phase change detection has not been published widely. This is mainly because of the long revisit times of common SAR sensors leading to temporal decorrelation. This situation has changed dramatically with the advent of the TanDEM-X constellation, which can create single-pass interferograms from space at very high resolutions, avoiding temporal decorrelation almost completely. In this paper the basic structures that are present for any building in InSAR phases, i.e. layover, shadow, and roof areas, are examined. Approaches for their extraction from TanDEM-X interferograms are developed using simulated SAR interferograms. The extracted features of the building signature will in the future be used for urban change detection in real TanDEM-X High Resolution Spotlight interferograms.

A New Comptonization Model for Weakly Magnetized Accreting NS LMXBs

Science.gov (United States)

Paizis, A.; Farinelli, R.; Titarchuk, L.; Frontera, F.; Cocchi, M.; Ferrigno, C.

2009-05-01

We have developed a new Comptonization model to propose, for the first time, a self consistent physical interpretation of the complex spectral evolution seen in NS LMXBs. The model and its application to LMXBs are presented and compared to the Simbol-X expected capabilities.

Cross-correlating Cosmic IR and X-ray Background Fluctuations: Evidence of Significant Black Hole Populations Among the CIB Sources

Science.gov (United States)

Cappelluti, N.; Kashlinsky, A.; Arendt, R. G.; Comastri, A.; Fazio, G. G.; Finoguenov, A.; Hasinger, G.; Mather, J. C.; Miyaji, T; Moseley, S. H.

2013-01-01

In order to understand the nature of the sources producing the recently uncovered cosmic infrared background (CIB) fluctuations, we study cross-correlations between the fluctuations in the source-subtracted CIB from Spitzer/IRAC data and the unresolved cosmic X-ray background from deep Chandra observations. Our study uses data from the EGS/AEGIS field, where both data sets cover an approx = 8' x 45' region of the sky. Our measurement is the cross-power spectrum between the IR and X-ray data. The cross-power signal between the IRAC maps at 3.6 micron and 4.5 micron and the Chandra [0.5-2] keV data has been detected, at angular scales approx >20'', with an overall significance of approx = 3.8 sigma and approx. = 5.6 sigma, respectively. At the same time we find no evidence of significant cross-correlations at the harder Chandra bands. The cross-correlation signal is produced by individual IR sources with 3.6 micron and 4.5 micron magnitudes m(sub AB) approx. > 25-26 and [0.5-2] keV X-ray fluxes black holes than among the known populations. We discuss the various possible origins for the cross-power signal and show that neither local foregrounds nor the known remaining normal galaxies and active galactic nuclei can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations. local foregrounds, nor the known remaining normal galaxies and active galactic nuclei (AGN) can reproduce the measurements. These observational results are an important new constraint on theoretical modeling of the near-IR CIB fluctuations

Method for reducing x-ray background signals from insertion device x-ray beam position monitors

Directory of Open Access Journals (Sweden)

Glenn Decker

1999-11-01

Full Text Available A method is described that provides a solution to the long-standing problem of stray radiation-induced signals on photoemission-based x-ray beam position monitors (BPMs located on insertion device x-ray beam lines. The method involves the introduction of a chicane into the accelerator lattice that directs unwanted x radiation away from the photosensitive x-ray BPM blades. This technique has been implemented at the Advanced Photon Source, and experimental confirmation of the technique is provided.

Simulation of x-rays in refractive structure by the Monte Carlo method using the supercomputer SKIF

International Nuclear Information System (INIS)

Yaskevich, Yu.R.; Kravchenko, O.I.; Soroka, I.I.; Chembrovskij, A.G.; Kolesnik, A.S.; Serikova, N.V.; Petrov, P.V.; Kol'chevskij, N.N.

2013-01-01

Software 'Xray-SKIF' for the simulation of the X-rays in refractive structures by the Monte-Carlo method using the supercomputer SKIF BSU are developed. The program generates a large number of rays propagated from a source to the refractive structure. The ray trajectory under assumption of geometrical optics is calculated. Absorption is calculated for each ray inside of refractive structure. Dynamic arrays are used for results of calculation rays parameters, its restore the X-ray field distributions very fast at different position of detector. It was found that increasing the number of processors leads to proportional decreasing of calculation time: simulation of 10 8 X-rays using supercomputer with the number of processors from 1 to 30 run-times equal 3 hours and 6 minutes, respectively. 10 9 X-rays are calculated by software 'Xray-SKIF' which allows to reconstruct the X-ray field after refractive structure with a special resolution of 1 micron. (authors)

Simulation Studies of the X-Ray Free-Electron Laser Oscillator

International Nuclear Information System (INIS)

Lindberg, R.R.; Shyd'ko, Y.; Kim, K.-J; Fawley, W.M.

2009-01-01

Simulations of the x-ray free-electron laser (FEL) oscillator are presented that include transverse effects and realistic Bragg crystal properties with the two-dimensional code GINGER. In the present cases considered the radiation divergence is much narrower than the crystal acceptance, and the numerical algorithm can be simplified by ignoring the finite angular bandwidth of the crystal. In this regime GINGER shows that the saturated x-ray pulses have 109 photons and are nearly Fourier-limited with peak powers in excess of 1 MW. Wealso include preliminary results for a four-mirror cavity that can be tuned in wavelength over a few percent, with future plans to incorporate the full transverse response of the Bragg crystals into GINGER to more accurately model this tunable source.

Characterization of Background Traffic in Hybrid Network Simulation

National Research Council Canada - National Science Library

Lauwens, Ben; Scheers, Bart; Van de Capelle, Antoine

2006-01-01

.... Two approaches are common: discrete event simulation and fluid approximation. A discrete event simulation generates a huge amount of events for a full-blown battlefield communication network resulting in a very long runtime...

High Spectral Resolution Observation of the Soft Diffuse X-ray Background in the Direction of the Galactic Anti-Center

Science.gov (United States)

Wulf, Dallas; Eckart, Mega E.; Galeazzi, Massimiliano; Jaeckel, Felix; Kelley, Richard L.; Kilbourne, Caroline A.; McCammon, Dan; Morgan, Kelsey M.; Porter, Frederick S.; Szymkowiak, Andrew E.

2018-01-01

High spectral resolution observations in the soft x-rays are necessary for understanding and modelling the hot component of the interstellar medium and its contribution to the Soft X-ray Background (SXRB). This extended source emission cannot be resolved with most wavelength dispersive spectrometers, making energy dispersive microcalorimeters the ideal choice for these observations. We present here the analysis of the most recent sounding rocket flight of the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC), a large area silicon thermistor microcalorimeter. This 111 second observation integrates a nearly 1 steradian field of view in the direction of the galactic anti-center (l, b = 165°, -5°) and features ~5 eV spectral resolution below 1 keV. Direct comparison will also be made to the previous, high-latitude observations.

Caliste 64, an innovative CdTe hard X-ray micro-camera

Energy Technology Data Exchange (ETDEWEB)

Meuris, A.; Limousin, O.; Pinsard, F.; Le Mer, I. [CEA Saclay, DSM, DAPNIA, Serv. Astrophys., F-91191 Gif sur Yvette (France); Lugiez, F.; Gevin, O.; Delagnes, E. [CEA Saclay, DSM, DAPNIA, Serv. Electron., F-91191 Gif sur Yvette (France); Vassal, M.C.; Soufflet, F.; Bocage, R. [3D-plus Company, F-78532 Buc (France)

2008-07-01

A prototype 64 pixel miniature camera has been designed and tested for the Simbol-X hard X-ray observatory to be flown on the joint CNES-ASI space mission in 2014. This device is called Caliste 64. It is a high performance spectro-imager with event time-tagging capability, able to detect photons between 2 keV and 250 keV. Caliste 64 is the assembly of a 1 or 2 min thick CdTe detector mounted on top of a readout module. CdTe detectors equipped with Aluminum Schottky barrier contacts are used because of their very low dark current and excellent spectroscopic performance. Front-end electronics is a stack of four IDeF-X V1.1 ASICs, arranged perpendicular to the detection plane, to read out each pixel independently. The whole camera fits in a 10 * 10 * 20 mm{sup 3} volume and is juxtaposable on its four sides. This allows the device to be used as an elementary unit in a larger array of Caliste 64 cameras. Noise performance resulted in an ENC better than 60 electrons rms in average. The first prototype camera is tested at -10 degrees C with a bias of -400 V. The spectrum summed across the 64 pixels results in a resolution of 697 eV FWHM at 13.9 keV and 808 eV FWFM at 59.54 keV. (authors)

Local ISM 3D Distribution and Soft X-ray Background Inferences for Nearby Hot Gas

Science.gov (United States)

Puspitarini, L.; Lallement, R.; Snowden, Steven L.; Vergely, J.-L.; Snowden, S.

2014-01-01

Three-dimensional (3D) interstellar medium (ISM) maps can be used to locate not only interstellar (IS) clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae, and are filled by hot gas. To demonstrate this, and to derive a clearer picture of the local ISM, we compare our recent 3D IS dust distribution maps to the ROSAT diffuse Xray background maps after removal of heliospheric emission. In the Galactic plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the soft (0.25 keV) background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust to gas ratio and homogeneous 106 K hot gas filling the cavities, we modeled in a simple way the 0.25 keV surface brightness along the Galactic plane as seen from the Sun, taking into account the absorption by the mapped clouds. The data-model comparison favors the existence of hot gas in the solar neighborhood, the so-called Local Bubble (LB). The inferred mean pressure in the local cavities is found to be approx.9,400/cu cm K, in agreement with previous studies, providing a validation test for the method. On the other hand, the model overestimates the emission from the huge cavities located in the third quadrant. Using CaII absorption data, we show that the dust to CaII ratio is very small in those regions, implying the presence of a large quantity of lower temperature (non-X-ray emitting) ionized gas and as a consequence a reduction of the volume filled by hot gas, explaining at least part of the discrepancy. In the meridian plane, the two main brightness enhancements coincide well with the LB's most elongated parts and chimneys connecting the LB to the halo, but no particular nearby cavity is found towards the enhancement in the direction of the bright North Polar Spur (NPS) at high latitude. We searched in the 3D maps for the source regions of the higher energy

Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

International Nuclear Information System (INIS)

Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

2009-01-01

Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

Impact of the vertical emission profiles on background gas-phase pollution simulated from the EMEP emissions over Europe

Directory of Open Access Journals (Sweden)

S. Mailler

2013-06-01

Full Text Available Five one-year air quality simulations over a domain covering Europe have been performed using the CHIMERE chemistry transport model and the EMEP emission dataset for Europe. These five simulations differ only by the representation of the effective emission heights for anthropogenic emissions: one has been run using the EMEP standard recommendations, three others with vertical injection profiles derived from the EMEP recommendations but multiplying the injection height by 0.75, 0.50 and 0.25, respectively, while the last one uses vertical profiles derived from the recent literature. It is shown that using injection heights lower than the EMEP recommendations leads to significantly improved simulation of background SO2, NO2 and O3 concentrations when compared to the Airbase station measurements.

SINDBAD: a realistic multi-purpose and scalable X-ray simulation tool for NDT applications

International Nuclear Information System (INIS)

Tabary, J.; Hugonnard, P.; Mathy, F.

2007-01-01

The X-ray radiographic simulation software SINDBAD, has been developed to help the design stage of radiographic systems or to evaluate the efficiency of image processing techniques, in both medical imaging and Non-Destructive Evaluation (NDE) industrial fields. This software can model any radiographic set-up, including the X-ray source, the beam interaction inside the object represented by its Computed Aided Design (CAD) model, and the imaging process in the detector. For each step of the virtual experimental bench, SINDBAD combines different modelling modules, accessed via Graphical User Interfaces (GUI), to provide realistic synthetic images. In this paper, we present an overview of all the functionalities which are available in SINDBAD, with a complete description of all the physics taken into account in models as well as the CAD and GUI facilities available in many computing platforms. We underline the different modules usable for different applications which make SINDBAD a multi-purposed and scalable X-ray simulation tool. (authors)

Early MIMD experience with a plasma physics simulation program on the CRAY X-MP

International Nuclear Information System (INIS)

Rhoades, C.E. Jr.

1986-02-01

This paper describes some early experience with converting a plasma physics simulation program to the CRAY X-MP, a current multiple instruction, multiple data (MIMD) computer consisting of two processors with architecture similar to that of the CRAY-1. The computer program used in this study is an all Fortran version of SELF, a two species, one space, two velocity, electromagnetic, Newtonian, particle in cell, plasma simulation code. The approach to converting SELF to use both processors of the CRAY X-MP is described in some detail. The resulting multiprocessor version of SELF is nearly a factor of two faster in real time than the single processor version. The multiprocessor version obtains 58.2+-.1 seconds of central processor time in 30+-.5 seconds of real time. For comparison, the CRAY-1 execution time if 74.5 seconds. For SELF, which is mostly scalar coding, the CRAY X-MP is about 2.5 times faster overall than the CRAY-1

Annual radiation background in Isfahan city

International Nuclear Information System (INIS)

Tavakoli, Mohammad B.

2002-01-01

Measurement of environmental exposure is very important from different points of view. It is especially important for human health. It has been measured accurately in many countries. In Iran, it is also measured in some cities especially in high background areas such as Ramsar, but there is not any measurement in Isfahan. Measurement of background radiation in this study is performed using TLD method. The TLDs used are made from CaSO 4 :Dy, which is very sensitive. The locations under investigations in this research were 52 health centers distributed all around Isfahan city. Each TLD badge was put in a special plastic bag and left over the roofs of the selected health center for a month. The procedure was repeated for all 12 months of the year 1379(21 st March 2000 to 20 th March 2001). The results were used to obtain mean and SD in each month and at different places. The maximum and the minimum of obtained results for dose equivalent in different months and locations were 15.9x10 -2 and 6.5x10 -2 mSv. Obtained maximum and minimum of the means between all the locations were 10.5x10 -2 and 8.6x10 2 mSv for the whole year. Monthly mean and SD for Isfahan city for the whole year were 9.7x10 -2 and 1.5x10 -2 respectively therefore mean annual dose equivalent in Isfahan city is 1.16mSv. The results do not show any high background radiation area

Monte-Carlo estimation of the inflight performance of the GEMS satellite x-ray polarimeter

Science.gov (United States)

Kitaguchi, Takao; Tamagawa, Toru; Hayato, Asami; Enoto, Teruaki; Yoshikawa, Akifumi; Kaneko, Kenta; Takeuchi, Yoko; Black, Kevin; Hill, Joanne; Jahoda, Keith; Krizmanic, John; Sturner, Steven; Griffiths, Scott; Kaaret, Philip; Marlowe, Hannah

2014-07-01

We report a Monte-Carlo estimation of the in-orbit performance of a cosmic X-ray polarimeter designed to be installed on the focal plane of a small satellite. The simulation uses GEANT for the transport of photons and energetic particles and results from Magboltz for the transport of secondary electrons in the detector gas. We validated the simulation by comparing spectra and modulation curves with actual data taken with radioactive sources and an X-ray generator. We also estimated the in-orbit background induced by cosmic radiation in low Earth orbit.

Large angle cosmic microwave background fluctuations from cosmic strings with a cosmological constant

International Nuclear Information System (INIS)

Landriau, M.; Shellard, E.P.S.

2004-01-01

In this paper, we present results for large-angle cosmic microwave background anisotropies generated from high resolution simulations of cosmic string networks in a range of flat Friedmann-Robertson-Walker universes with a cosmological constant. Using an ensemble of all-sky maps, we compare with the Cosmic Background Explorer data to infer a normalization (or upper bound) on the string linear energy density μ. For a flat matter-dominated model (Ω M =1) we find Gμ/c 2 ≅0.7x10 -6 , which is lower than previous constraints probably because of the more accurate inclusion of string small-scale structure. For a cosmological constant within an observationally acceptable range, we find a relatively weak dependence with Gμ/c 2 less than 10% higher

On semiclassical analysis of pure spinor superstring in an AdS{sub 5} x S{sup 5} background

Energy Technology Data Exchange (ETDEWEB)

Aisaka, Yuri [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sao Paulo State Univ. (Brazil). Inst. de Fisica Teorica; Ibiapina Bevilaqua, L. [Univ. Federal do Rio Grande do Norte, Natal (Brazil). Esola de Ciencias e Tecnologia; Vallilo, Brenno C. [Santiago Univ. (Chile). Dept. de Ciencias Fisicas

2012-06-15

Relation between semiclassical analyses of Green-Schwarz and pure spinor formalisms in an AdS{sub 5} x S{sup 5} background is clarified. It is shown that the two formalisms have identical semiclassical partition functions for a simple family of classical solutions. It is also shown that, when the classical string is furthermore rigid, this in turn implies that the two formalisms predict the same one-loop corrections to spacetime energies.

Simulation and optimization of the SIRIUS IPE soft x-ray beamline

Science.gov (United States)

Meyer, Bernd C.; Rocha, Tulio C. R.; Luiz, Sergio A. L.; C. Pinto, Artur; Westfahl, Harry

2017-08-01

The soft X-ray beamline IPE is one of the first phase SIRIUS beamlines at the LNLS, Brazil. Divided into two branches, IPE is designed to perform ambient pressure X-ray photo-electron spectroscopy (AP-XPS) and high resolution resonant inelastic X-ray scattering (RIXS) for samples in operando/environmental conditions inside cells and liquid jets. The aim is to maximize the photon flux in the energy range 200-1400 eV generated by an elliptically polarizing undulator source (EPU) and focus it to a 1 μm vertical spot size at the RIXS station and 10 μm at the AP-XPS station. In order to achieve the required resolving power (40.000 at 930 eV) for RIXS both the dispersion properties of the plane grating monochromator (PGM) and the thermal deformation of the optical elements need special attention. The grating parameters were optimized with the REFLEC code to maximize the efficiency at the required resolution. Thermal deformation of the PGM plane mirror limits the possible range of cff parameters depending of the photon energy used. Hence, resolution of the PGM and thermal deformation effects define the boundary conditions of the optical concept and the simulations of the IPE beamline. We compare simulations performed by geometrical ray-tracing (SHADOW) and wave front propagation (SRW) and show that wave front diffraction effects (apertures, optical surface error profiles) has a small effect on the beam spot size and shape.

Black-hole Binaries: Life Begins at 40 keV

Science.gov (United States)

Belloni, Tomaso M.; Motta, Sara

2009-05-01

In the study of black-hole transients, an important problem that still needs to be answered is how the high-energy part of the spectrum evolves from the low-hard to the high-soft state, given that they have very different properties. Recent results obtained with RXTE and INTEGRAL have given inconsistent results. With RXTE, we have found that the high-energy cutoff in GX 339-4 during the transition first decreases (during the low-hard state), then increases again across the Hard-Intermediate state, to become unmeasurable in the soft states (possibly because of statistical limitations). We show Simbol-X will be able to determine the spectral shape with superb accuracy. As the high-energy part of the spectrum is relatively less known than the one below 20 keV, Simbol-X will provide important results that will help out understanding of the extreme physical conditions in the vicinity of a stellar-mass black hole.

A GEANT4 based simulation for pixelated X-ray hybrid detectors

International Nuclear Information System (INIS)

Marinho, F.; Akiba, K.

2015-01-01

In this letter we present a detailed Monte Carlo approach to simulate pixelated detectors for X-ray applications. It allows us to fully characterize quantities such as interaction probability and reconstructed energy deposits according to beam energy as to evaluate energy and position resolution for comparisons with experimental results. The implementation and use of Monte Carlo truth information is also discussed

New challenges in ray tracing simulations of X-ray optics

International Nuclear Information System (INIS)

Río, M Sánchez del

2013-01-01

The construction of new synchrotron sources and the refurbishment and upgrade of existing ones has boosted in the last years the interest in X-ray optics simulations for beamline design and optimization. In the last years we conducted a full renewal of the well established SHADOW ray tracing code, ending with a modular version SHADOW3 interfaced to multiple programming languages (C, C++, IDL, Python). Some of the new features of SHADOW3 are presented. From the physics point of view, SHADOW3 has been upgraded for dealing with lens systems. X-ray partial coherence applications demand an extension of traditional ray tracing methods into a hybrid ray-tracing wave-optics approach. The software development is essential for fulfilling the requests of the ESRF Upgrade Programme, and some examples of calculations are also presented.

X-ray convergent beam pattern simulation using the Moodie-Wagenfeld equations: 3-beam Laue case

International Nuclear Information System (INIS)

Liu, L.; Goodman, P.

1998-01-01

Pattern simulations for 3-beam X-ray diffraction are presented, by multi-slice calculations based on Moodie and Wagenfeld's formulation of the X-ray equations, which factorise Maxwell's equations into Dirac format, using circular-polarisation bases. The results are presented in the form of convergent-beam patterns for each diffraction order, using experience gained from CBED (convergent beam electron diffraction) and LACBED (large-angle CBED), since this displays the results in the most compact form. The acronym CBXRAD (convergent-beam X-ray-diffraction) is used for these patterns. Although optics required for the complete patterns is not currently available, capillary focussing is undergoing rapid development, and our simulations define critical angular ranges within reach of current designs. Simulations for light and heavy-atoms structures belonging to the enantiomorphic space-group pair P3 1 21 and P3 2 21, provide clear evidence of chiral interaction between radiation and structure, highlighting divergences from the well studied CBED pattern symmetries. MoKα 1 and TaKα 1 wavelengths were used to minimise absorption for the two structures respectively, although 'anomalous absorption' is always important due to the large thicknesses required (up to 20 mm)

Simulation study of spatial resolution in phase-contrast X-ray imaging with Takagi-Taupin equation

International Nuclear Information System (INIS)

Koyama, Ichiro; Momose, Atsushi

2003-01-01

To evaluate attainable spatial resolution of phase-contrast X-ray imaging using an LLL X-ray interferometer with a thin crystal wafer, a computer simulation study with Takagi-Taupin equation was performed. Modulation transfer function of the wafer for X-ray phase was evaluated. For a polyester film whose thickness is 0.1 mm, it was concluded that the spatial resolution can be improved up to 3 μm by thinning the wafer, under our experimental condition

Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer.

Science.gov (United States)

Ale, Angelique; Ermolayev, Vladimir; Deliolanis, Nikolaos C; Ntziachristos, Vasilis

2013-05-01

The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method. Despite this progress, the detection sensitivity of targeted fluorescence agents remains limited by nonspecific background accumulation of the fluorochrome employed, which complicates early detection of murine cancers. Therefore we examine whether x-ray CT information and bulk fluorescence detection can be combined to increase detection sensitivity. Correspondingly, we research the performance of a data-driven fluorescence background estimator employed for subtraction of background fluorescence from acquisition data. Using mice containing known fluorochromes ex vivo, we demonstrate the reduction of background signals from reconstructed images and sensitivity improvements. Finally, by applying the method to in vivo data from K-ras transgenic mice developing lung cancer, we find small tumors at an early stage compared with reconstructions performed using raw data. We conclude with the benefits of employing fluorescence subtraction in hybrid FMT-XCT for early detection studies.

Boson-mediated quantum spin simulators in transverse fields: X Y model and spin-boson entanglement

Science.gov (United States)

Wall, Michael L.; Safavi-Naini, Arghavan; Rey, Ana Maria

2017-01-01

The coupling of spins to long-wavelength bosonic modes is a prominent means to engineer long-range spin-spin interactions, and has been realized in a variety of platforms, such as atoms in optical cavities and trapped ions. To date, much of the experimental focus has been on the realization of long-range Ising models, but generalizations to other spin models are highly desirable. In this work, we explore a previously unappreciated connection between the realization of an X Y model by off-resonant driving of a single sideband of boson excitation (i.e., a single-beam Mølmer-Sørensen scheme) and a boson-mediated Ising simulator in the presence of a transverse field. In particular, we show that these two schemes have the same effective Hamiltonian in suitably defined rotating frames, and analyze the emergent effective X Y spin model through a truncated Magnus series and numerical simulations. In addition to X Y spin-spin interactions that can be nonperturbatively renormalized from the naive Ising spin-spin coupling constants, we find an effective transverse field that is dependent on the thermal energy of the bosons, as well as other spin-boson couplings that cause spin-boson entanglement not to vanish at any time. In the case of a boson-mediated Ising simulator with transverse field, we discuss the crossover from transverse field Ising-like to X Y -like spin behavior as a function of field strength.

Development and validation of real-time simulation of X-ray imaging with respiratory motion.

Science.gov (United States)

Vidal, Franck P; Villard, Pierre-Frédéric

2016-04-01

We present a framework that combines evolutionary optimisation, soft tissue modelling and ray tracing on GPU to simultaneously compute the respiratory motion and X-ray imaging in real-time. Our aim is to provide validated building blocks with high fidelity to closely match both the human physiology and the physics of X-rays. A CPU-based set of algorithms is presented to model organ behaviours during respiration. Soft tissue deformation is computed with an extension of the Chain Mail method. Rigid elements move according to kinematic laws. A GPU-based surface rendering method is proposed to compute the X-ray image using the Beer-Lambert law. It is provided as an open-source library. A quantitative validation study is provided to objectively assess the accuracy of both components: (i) the respiration against anatomical data, and (ii) the X-ray against the Beer-Lambert law and the results of Monte Carlo simulations. Our implementation can be used in various applications, such as interactive medical virtual environment to train percutaneous transhepatic cholangiography in interventional radiology, 2D/3D registration, computation of digitally reconstructed radiograph, simulation of 4D sinograms to test tomography reconstruction tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

Epp: A C++ EGSnrc user code for x-ray imaging and scattering simulations

International Nuclear Information System (INIS)

Lippuner, Jonas; Elbakri, Idris A.; Cui Congwu; Ingleby, Harry R.

2011-01-01

Purpose: Easy particle propagation (Epp) is a user code for the EGSnrc code package based on the C++ class library egspp. A main feature of egspp (and Epp) is the ability to use analytical objects to construct simulation geometries. The authors developed Epp to facilitate the simulation of x-ray imaging geometries, especially in the case of scatter studies. While direct use of egspp requires knowledge of C++, Epp requires no programming experience. Methods: Epp's features include calculation of dose deposited in a voxelized phantom and photon propagation to a user-defined imaging plane. Projection images of primary, single Rayleigh scattered, single Compton scattered, and multiple scattered photons may be generated. Epp input files can be nested, allowing for the construction of complex simulation geometries from more basic components. To demonstrate the imaging features of Epp, the authors simulate 38 keV x rays from a point source propagating through a water cylinder 12 cm in diameter, using both analytical and voxelized representations of the cylinder. The simulation generates projection images of primary and scattered photons at a user-defined imaging plane. The authors also simulate dose scoring in the voxelized version of the phantom in both Epp and DOSXYZnrc and examine the accuracy of Epp using the Kawrakow-Fippel test. Results: The results of the imaging simulations with Epp using voxelized and analytical descriptions of the water cylinder agree within 1%. The results of the Kawrakow-Fippel test suggest good agreement between Epp and DOSXYZnrc. Conclusions: Epp provides the user with useful features, including the ability to build complex geometries from simpler ones and the ability to generate images of scattered and primary photons. There is no inherent computational time saving arising from Epp, except for those arising from egspp's ability to use analytical representations of simulation geometries. Epp agrees with DOSXYZnrc in dose calculation, since

Numerical simulation of SPH for dynamics effect of multilayer discontinuous structure irradiated by impulse X-ray

International Nuclear Information System (INIS)

Xu Binbin; Tang Wenhui; Ran Xianwen; Xu Zhihong; Chen Hua

2012-01-01

When high energy X-ray irradiates material, it will cause energy deposition in materials, and generates thermal shock wave. At present, finite difference method is used to the numerical simulation of thermal shock usually, but if considering the inter-space between the multilayer materials, the difference method will be more difficult. This paper used the SPH method to simulate multilayer discontinuous structure irradiated by high energy X-ray, and the results show that the gap between the materials of each layer has a certain influence on the thermal shock wave intensity, but doesn't have any affect to gasification impulse. (authors)

Beam-induced backgrounds in detectors at the ILC

Energy Technology Data Exchange (ETDEWEB)

Vogel, Adrian

2008-11-15

There is general consensus in the high-energy physics community that the next particle collider to be built should be a linear electron-positron accelerator. Such a machine, colliding point-like particles with a well-defined initial state, would be an ideal complement to the Large Hadron Collider (LHC) and would allow high-precision measurements of the new physics phenomena that are likely to be discovered at the TeV energy scale. The most advanced project in that context is the International Linear Collider (ILC), aiming for a centre-of-mass energy of 500 GeV and a luminosity of 2 x 10{sup 34} cm{sup -2}s{sup -1} in its first stage. One of the detector concepts that are currently being developed and studied is the so-called International Large Detector (ILD). A prime feature of the ILD concept is the usage of a Time Projection Chamber (TPC) as the main tracker, which allows to reach the required momentum resolution, but which also has excellent particle identification capabilities and a highly robust and efficient tracking. The beam-beam interaction of the strongly focused particle bunches at the ILC will produce beamstrahlung photons, which can in turn scatter to electron-positron pairs. These pairs are a major source of detector backgrounds. This thesis explains the methods to study the effects of beam-induced electron-positron pair backgrounds with Mokka, a full detector simulation for the ILC that is based on Geant4, and it presents the simulation results for different detector configurations and various small modifications. The main focus of the simulations and their analysis is on the vertex detector and the TPC, but results for the inner silicon trackers and the hadronic calorimeters are shown as well. (orig.)

Beam-induced backgrounds in detectors at the ILC

International Nuclear Information System (INIS)

Vogel, Adrian

2008-11-01

There is general consensus in the high-energy physics community that the next particle collider to be built should be a linear electron-positron accelerator. Such a machine, colliding point-like particles with a well-defined initial state, would be an ideal complement to the Large Hadron Collider (LHC) and would allow high-precision measurements of the new physics phenomena that are likely to be discovered at the TeV energy scale. The most advanced project in that context is the International Linear Collider (ILC), aiming for a centre-of-mass energy of 500 GeV and a luminosity of 2 x 10 34 cm -2 s -1 in its first stage. One of the detector concepts that are currently being developed and studied is the so-called International Large Detector (ILD). A prime feature of the ILD concept is the usage of a Time Projection Chamber (TPC) as the main tracker, which allows to reach the required momentum resolution, but which also has excellent particle identification capabilities and a highly robust and efficient tracking. The beam-beam interaction of the strongly focused particle bunches at the ILC will produce beamstrahlung photons, which can in turn scatter to electron-positron pairs. These pairs are a major source of detector backgrounds. This thesis explains the methods to study the effects of beam-induced electron-positron pair backgrounds with Mokka, a full detector simulation for the ILC that is based on Geant4, and it presents the simulation results for different detector configurations and various small modifications. The main focus of the simulations and their analysis is on the vertex detector and the TPC, but results for the inner silicon trackers and the hadronic calorimeters are shown as well. (orig.)

Optimization of the Penelope code in F language for the simulation of the X-ray spectrum in radiodiagnosis

International Nuclear Information System (INIS)

Ballon P, C. I.; Quispe V, N. Y.; Vega R, J. L. J.

2017-10-01

The computational simulation to obtain the X-ray spectrum in the range of radio-diagnosis, allows a study and advance knowledge of the transport process of X-rays in the interaction with matter using the Monte Carlo method. With the obtaining of the X-ray spectra we can know the dose that the patient receives when he undergoes a radiographic study or CT, improving the quality of the obtained image. The objective of the present work was to implement and optimize the open source Penelope (Monte Carlo code for the simulation of the transport of electrons and photons in the matter) 2008 version programming extra code in functional language F, managing to double the processing speed, thus reducing the simulation time spent and errors when optimizing the software initially programmed in Fortran 77. The results were compared with those of Penelope, obtaining a good concordance. We also simulated the obtaining of a Pdd curve (depth dose profile) for a Theratron Equinox cobalt-60 teletherapy device, also validating the software implemented for high energies. (Author)

A wide field X-ray camera

International Nuclear Information System (INIS)

Sims, M.; Turner, M.J.L.; Willingale, R.

1980-01-01

A wide field of view X-ray camera based on the Dicke or Coded Mask principle is described. It is shown that this type of instrument is more sensitive than a pin-hole camera, or than a scanning survey of a given region of sky for all wide field conditions. The design of a practical camera is discussed and the sensitivity and performance of the chosen design are evaluated by means of computer simulations. The Wiener Filter and Maximum Entropy methods of deconvolution are described and these methods are compared with each other and cross-correlation using data from the computer simulations. It is shown that the analytic expressions for sensitivity used by other workers are confirmed by the simulations, and that ghost images caused by incomplete coding can be substantially eliminated by the use of the Wiener Filter and the Maximum Entropy Method, with some penalty in computer time for the latter. The cyclic mask configuration is compared with the simple mask camera. It is shown that when the diffuse X-ray background dominates, the simple system is more sensitive and has the better angular resolution. When sources dominate the simple system is less sensitive. It is concluded that the simple coded mask camera is the best instrument for wide field imaging of the X-ray sky. (orig.)

Simulation of photon and charge transport in X-ray imaging semiconductor sensors

CERN Document Server

Nilsson, H E; Hjelm, M; Bertilsson, K

2002-01-01

A fully stochastic model for the imaging properties of X-ray silicon pixel detectors is presented. Both integrating and photon counting configurations have been considered, as well as scintillator-coated structures. The model is based on three levels of Monte Carlo simulations; photon transport and absorption using MCNP, full band Monte Carlo simulation of charge transport and system level Monte Carlo simulation of the imaging performance of the detector system. In the case of scintillator-coated detectors, the light scattering in the detector layers has been simulated using a Monte Carlo method. The image resolution was found to be much lower in scintillator-coated systems due to large light spread in thick scintillator layers. A comparison between integrating and photon counting readout methods shows that the image resolution can be slightly enhanced using a photon-counting readout. In addition, the proposed model has been used to study charge-sharing effects on the energy resolution in photon counting dete...

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.

Quantifying the effect of anode surface roughness on diagnostic x-ray spectra using Monte Carlo simulation

Energy Technology Data Exchange (ETDEWEB)

Mehranian, A.; Ay, M. R.; Alam, N. Riyahi; Zaidi, H. [Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of) and Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, P.O. Box 14185-615, Tehran (Iran, Islamic Republic of) and Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, P.O. Box 14155-6447, Tehran (Iran, Islamic Republic of); Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland) and Geneva Neuroscience Center, Geneva University, CH-1205 Geneva (Switzerland)

2010-02-15

Purpose: The accurate prediction of x-ray spectra under typical conditions encountered in clinical x-ray examination procedures and the assessment of factors influencing them has been a long-standing goal of the diagnostic radiology and medical physics communities. In this work, the influence of anode surface roughness on diagnostic x-ray spectra is evaluated using MCNP4C-based Monte Carlo simulations. Methods: An image-based modeling method was used to create realistic models from surface-cracked anodes. An in-house computer program was written to model the geometric pattern of cracks and irregularities from digital images of focal track surface in order to define the modeled anodes into MCNP input file. To consider average roughness and mean crack depth into the models, the surface of anodes was characterized by scanning electron microscopy and surface profilometry. It was found that the average roughness (R{sub a}) in the most aged tube studied is about 50 {mu}m. The correctness of MCNP4C in simulating diagnostic x-ray spectra was thoroughly verified by calling its Gaussian energy broadening card and comparing the simulated spectra with experimentally measured ones. The assessment of anode roughness involved the comparison of simulated spectra in deteriorated anodes with those simulated in perfectly plain anodes considered as reference. From these comparisons, the variations in output intensity, half value layer (HVL), heel effect, and patient dose were studied. Results: An intensity loss of 4.5% and 16.8% was predicted for anodes aged by 5 and 50 {mu}m deep cracks (50 kVp, 6 deg. target angle, and 2.5 mm Al total filtration). The variations in HVL were not significant as the spectra were not hardened by more than 2.5%; however, the trend for this variation was to increase with roughness. By deploying several point detector tallies along the anode-cathode direction and averaging exposure over them, it was found that for a 6 deg. anode, roughened by 50 {mu}m deep

Impact of Improved Heat Sinking of an X-Ray Calorimeter Array on Crosstalk, Noise, and Background Events

Science.gov (United States)

Kilbourne, C. A.; Adams, J. S.; Brekosky, R. P.; Chervenak, J. A.; Chiao, M. P.; Kelley, R. L.; Kelly, D. P.; Porter, F. S.

2011-01-01

The x-ray calorimeter array of the Soft X-ray Spectrometer (SXS) of the Astro-H satellite will incorporate a silicon thermistor array produced during the development of the X-Ray Spectrometer (XRS) of the Suzaku satellite. On XRS, inadequate heat sinking of the array led to several non-ideal effects. The thermal crosstalk, while too small to be confused with x-ray signals, nonetheless contributed a noise term that could be seen as a degradation in energy resolution at high flux. When energy was deposited in the silicon frame around the active elements of the array, such as by a cosmic ray, the resulting pulse in the temperature of the frame resulted in coincident signal pulses on most of the pixels. In orbit, the resolution was found to depend on the particle background rate. In order to minimize these effects on SXS, heat-sinking gold was applied to areas on the front and back of the array die, which was thermally anchored to the gold of its fanout board via gold wire bonds. The thermal conductance from the silicon chip to the fanout board was improved over that of XRS by an order of magnitude. This change was sufficient for essentially eliminating frame events and allowing high-resolution to be attained at much higher counting rates. We will present the improved performance, the measured crosstalk, and the results of the thermal characterization of such arrays.

Prospects of Ternary Cd1-x Zn x S as an Electron Transport Layer and Associated Interface Defects in a Planar Lead Halide Perovskite Solar Cell via Numerical Simulation

Science.gov (United States)

Chowdhury, Towhid Hossain; Ferdaous, Mohammad Tanvirul; Wadi, Mohd. Aizat Abdul; Chelvanathan, Puvaneswaran; Amin, Nowshad; Islam, Ashraful; Kamaruddin, Nurhafiza; Zin, Muhammad Irsyamuddin M.; Ruslan, Mohd Hafidz; Sopian, Kamaruzzaman Bin; Akhtaruzzaman, Md.

2018-03-01

In this study we present a ternary alloy, Cd1-x Zn x S as an electron transport layer for a planar lead halide perovskite solar cell via numerical simulation with solar cell capacitance simulator (SCAPS) software. Performance dependence on molar composition variation in the Cd1-x Zn x S alloy was studied for the mixed perovskite CH3NH3PbI3-x Cl x absorber and spiro-OMeTAD hole transport material in a planar perovskite solar cell. Additionally, the defects on both Cd1-x Zn x S/CH3NH3PbI3-x Cl x and CH3NH3PbI3-x Cl x /spiro-OMeTAD interface were thoroughly investigated. Simultaneously, a thickness of 700 nm for CH3NH3PbI3-x Cl x absorber with 50-nm-thick Cd0.2Zn0.8S (x = 0.8) was optimized. Analysis of the numerical solutions via SCAPS provides a trend and pattern for Cd0.2Zn0.8S as an effective electron transport layer for planar perovskite solar cells with a yield efficiency up to 24.83%. The planar perovskite solar cell shows an open-circuit voltage of 1.224 V, short-circuit current density of 25.283 mA/cm2 and a fill factor of 80.22.

A Monte Carlo simulation of scattering reduction in spectral x-ray computed tomography

DEFF Research Database (Denmark)

Busi, Matteo; Olsen, Ulrik Lund; Bergbäck Knudsen, Erik

2017-01-01

In X-ray computed tomography (CT), scattered radiation plays an important role in the accurate reconstruction of the inspected object, leading to a loss of contrast between the different materials in the reconstruction volume and cupping artifacts in the images. We present a Monte Carlo simulation...

Understanding NaI(Tl) crystal background for dark matter searches

Energy Technology Data Exchange (ETDEWEB)

Adhikari, G.; Adhikari, P.; Kong, S.Y.; Oh, S.Y. [Sejong University, Department of Physics and Astronomy, Seoul (Korea, Republic of); Ha, C.; Jeon, E.J.; Kim, N.Y.; Lee, H.S.; Park, J.S.; Park, K.S. [Institute for Basic Science (IBS), Center for Underground Physics, Daejeon (Korea, Republic of); Kim, Y.D. [Institute for Basic Science (IBS), Center for Underground Physics, Daejeon (Korea, Republic of); Sejong University, Department of Physics and Astronomy, Seoul (Korea, Republic of)

2017-07-15

We have developed ultra-low-background NaI(Tl) crystals to reproduce the DAMA results with the ultimate goal of achieving purity levels that are comparable to or better than those of the DAMA/LIBRA crystals. Even though the achieved background level does not approach that of DAMA/LIBRA, it is crucial to have a quantitative understanding of the backgrounds. We have studied background simulations toward a deeper understanding of the backgrounds and developed background models for a 9.16-kg NaI(Tl) crystal used in the test arrangement. In this paper we describe the contributions of background sources quantitatively by performing Geant4 Monte Carlo simulations that are fitted to the measured data to quantify the unknown fractions of the background compositions. In the fitted results, the overall simulated background spectrum well describes the measured data with a 9.16-kg NaI(Tl) crystal and shows that the background sources are dominated by surface {sup 210}Pb and internal {sup 40}K in the 2-6-keV energy interval, which produce 2.4 counts/day/keV/kg (dru) and 0.5 dru, respectively. (orig.)

The fractional Fourier transform as a simulation tool for lens-based X-ray microscopy

DEFF Research Database (Denmark)

Pedersen, Anders Filsøe; Simons, Hugh; Detlefs, Carsten

2018-01-01

The fractional Fourier transform (FrFT) is introduced as a tool for numerical simulations of X-ray wavefront propagation. By removing the strict sampling requirements encountered in typical Fourier optics, simulations using the FrFT can be carried out with much decreased detail, allowing...... the attenuation from the entire CRL using one or two effective apertures without loss of accuracy, greatly accelerating simulations involving CRLs. To demonstrate the applicability and accuracy of the FrFT, the imaging resolution of a CRL-based imaging system is estimated, and the FrFT approach is shown...

R.E.S.E.X. A computer simulation program for rare earth separation processes

International Nuclear Information System (INIS)

Casarci, M.; Gasparini, G.M.; Sanfilippo, L; Pozio, A.

1996-01-01

Lanthanides are most commonly separated using complex solvent extraction circuits. A simulation code has been developed by E.N.E.A. called R.E.S.E.X. (Rare Earth Solvent Extraction) which is able to simulate a solvent extraction battery up to 200 stages, using different configurations. The contemporary utilisation of an equilibrium data bank and of a simulation code allows the theoretical study of new rare earth separative processes or the optimisation of existing ones. As an example of this strategy are reported the results of the Pr/Nd separation in TBP 50 % in aromatic solvent

DIALETIKA ETNOGRAFI KOMUNIKASI EMIK-ETIK PADA KAIN TENUN

Directory of Open Access Journals (Sweden)

Emanuel S Leuape

2017-12-01

Full Text Available Penelitian ini bertujuan mendialetikakan pemaknaan emik-etik simbol warna dan gambar kain tenun (Mollo desa Tutem. Tahapan pada penelitian ini yaitu interpretasi (Ferdinand De Saussure, reinterpretasi (Roland Barthes, Dialog (Jurgen Habermas, dan dekonstruksi (Jaques Derrida. Hasil interpretasi (emik dan reinterpretasi (etik, didialetikakan dengan menghasilkan sintesis berupa dialog antara masyarakat Tutem dan peneliti, diakhiri dengan analisis dekonstruksi guna mengantisipasi potensi kemajemukan makna simbol warna dan gambar kain tenun desa Tutem di kemudian hari. Paradigma penelitiannya adalah kualitatif dan bermetode studi etnografi komunikasi. Data diperoleh dengan wawancara mendalam, observasi-partisipatoris, dan dokumentasi visual kain tenun. Hasil penelitian ini adalah: dalam pemaknaan emik masyarakat Tutem, simbol warna kain tenun mengacu pada keberagaman kelompok suku dan simbol gambar kain tenun merujuk kepada realitas historis. Pemaknaan etik peneliti, simbol warna dan gambar kain tenun merujuk kepada kondisi geografis (Sumber Daya Alam, moral dan perilaku sosial (Sumber Daya Manusia, dan sejarah. Melalui prosedur tindakan komunikatif (dialog, kesepakatan intersubjektif yang dicapai, mencakup: 10 jenis simbol warna dan 7 varian gambar kain tenun diterima dan 2 varian gambar kain tenun ditolak. Terdapat 3 jenis simbol warna dan pola gambar ruang kain tenun yang wajib didekonstruksi maknanya oleh peneliti. Proses interpretasi, reinterpretasi, dialog, dan dekonstruksi menjadi tahapan ideal dalam memberdayakan kain tenun sebagai salah satu wujud produk kebudayaan masyarakat Tutem. Pelaksanaan tahapan tersebut melibatkan peran aktif masyarakat Tutem dan peneliti. Akhirnya, masyarakat Tutem dan peneliti sama-sama membangun ‘cerita’ tentang simbol warna dan gambar kain tenun dalam spirit falibilisme.

Deterministic simulation of first-order scattering in virtual X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Freud, N. E-mail: nicolas.freud@insa-lyon.fr; Duvauchelle, P.; Pistrui-Maximean, S.A.; Letang, J.-M.; Babot, D

2004-07-01

A deterministic algorithm is proposed to compute the contribution of first-order Compton- and Rayleigh-scattered radiation in X-ray imaging. This algorithm has been implemented in a simulation code named virtual X-ray imaging. The physical models chosen to account for photon scattering are the well-known form factor and incoherent scattering function approximations, which are recalled in this paper and whose limits of validity are briefly discussed. The proposed algorithm, based on a voxel discretization of the inspected object, is presented in detail, as well as its results in simple configurations, which are shown to converge when the sampling steps are chosen sufficiently small. Simple criteria for choosing correct sampling steps (voxel and pixel size) are established. The order of magnitude of the computation time necessary to simulate first-order scattering images amounts to hours with a PC architecture and can even be decreased down to minutes, if only a profile is computed (along a linear detector). Finally, the results obtained with the proposed algorithm are compared to the ones given by the Monte Carlo code Geant4 and found to be in excellent accordance, which constitutes a validation of our algorithm. The advantages and drawbacks of the proposed deterministic method versus the Monte Carlo method are briefly discussed.

A statistical, task-based evaluation method for three-dimensional x-ray breast imaging systems using variable-background phantoms

International Nuclear Information System (INIS)

Park, Subok; Jennings, Robert; Liu Haimo; Badano, Aldo; Myers, Kyle

2010-01-01

Purpose: For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as digital breast tomosynthesis (DBT) and computed tomography, have drawn much attention from the medical imaging community, either academia or industry. However, there is still much room for understanding how to best optimize and evaluate the devices over a large space of many different system parameters and geometries. Current evaluation methods, which work well for 2D systems, do not incorporate the depth information from the 3D imaging systems. Therefore, it is critical to develop a statistically sound evaluation method to investigate the usefulness of inclusion of depth and background-variability information into the assessment and optimization of the 3D systems. Methods: In this paper, we present a mathematical framework for a statistical assessment of planar and 3D x-ray breast imaging systems. Our method is based on statistical decision theory, in particular, making use of the ideal linear observer called the Hotelling observer. We also present a physical phantom that consists of spheres of different sizes and materials for producing an ensemble of randomly varying backgrounds to be imaged for a given patient class. Lastly, we demonstrate our evaluation method in comparing laboratory mammography and three-angle DBT systems for signal detection tasks using the phantom's projection data. We compare the variable phantom case to that of a phantom of the same dimensions filled with water, which we call the uniform phantom, based on the performance of the Hotelling observer as a function of signal size and intensity. Results: Detectability trends calculated using the variable and uniform phantom methods are different from each other for both mammography and DBT systems. Conclusions: Our results indicate that measuring the system's detection performance with consideration of background variability may lead to differences in system performance

Simulation of enhanced characteristic x rays from a 40-MeV electron beam laser accelerated in plasma

Directory of Open Access Journals (Sweden)

L. Nikzad

2012-02-01

Full Text Available Simulation of x-ray generation from bombardment of various solid targets by quasimonoenergetic electrons is considered. The electron bunches are accelerated in a plasma produced by interaction of 500 mJ, 30 femtosecond laser pulses with a helium gas jet. These relativistic electrons propagate in the ion channel generated in the wake of the laser pulse. A beam of MeV electrons can interact with targets to generate x-ray radiation with keV energy. The MCNP-4C code based on Monte Carlo simulation is employed to compare the production of bremsstrahlung and characteristic x rays between 10 and 100 keV by using two quasi-Maxwellian and quasimonoenergetic energy distributions of electrons. For a specific electron spectrum and a definite sample, the maximum x-ray flux varies with the target thickness. Besides, by increasing the target atomic number, the maximum x-ray flux is increased and shifted towards a higher energy level. It is shown that by using the quasimonoenergetic electron profile, a more intense x ray can be produced relative to the quasi-Maxwellian profile (with the same total energy, representing up to 77% flux enhancement at K_{α} energy.

Simple method to estimate mean heart dose from Hodgkin lymphoma radiation therapy according to simulation X-rays.

Science.gov (United States)

van Nimwegen, Frederika A; Cutter, David J; Schaapveld, Michael; Rutten, Annemarieke; Kooijman, Karen; Krol, Augustinus D G; Janus, Cécile P M; Darby, Sarah C; van Leeuwen, Flora E; Aleman, Berthe M P

2015-05-01

To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case-control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor-intensive representative CT-based method. This simpler method may produce a

Simple Method to Estimate Mean Heart Dose From Hodgkin Lymphoma Radiation Therapy According to Simulation X-Rays

Energy Technology Data Exchange (ETDEWEB)

Nimwegen, Frederika A. van [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Cutter, David J. [Clinical Trial Service Unit, University of Oxford, Oxford (United Kingdom); Oxford Cancer Centre, Oxford University Hospitals NHS Trust, Oxford (United Kingdom); Schaapveld, Michael [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Rutten, Annemarieke [Department of Radiology, The Netherlands Cancer Institute, Amsterdam (Netherlands); Kooijman, Karen [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Krol, Augustinus D.G. [Department of Radiation Oncology, Leiden University Medical Center, Leiden (Netherlands); Janus, Cécile P.M. [Department of Radiation Oncology, Erasmus MC Cancer Center, Rotterdam (Netherlands); Darby, Sarah C. [Clinical Trial Service Unit, University of Oxford, Oxford (United Kingdom); Leeuwen, Flora E. van [Department of Psychosocial Research, Epidemiology, and Biostatistics, The Netherlands Cancer Institute, Amsterdam (Netherlands); Aleman, Berthe M.P., E-mail: b.aleman@nki.nl [Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam (Netherlands)

2015-05-01

Purpose: To describe a new method to estimate the mean heart dose for Hodgkin lymphoma patients treated several decades ago, using delineation of the heart on radiation therapy simulation X-rays. Mean heart dose is an important predictor for late cardiovascular complications after Hodgkin lymphoma (HL) treatment. For patients treated before the era of computed tomography (CT)-based radiotherapy planning, retrospective estimation of radiation dose to the heart can be labor intensive. Methods and Materials: Patients for whom cardiac radiation doses had previously been estimated by reconstruction of individual treatments on representative CT data sets were selected at random from a case–control study of 5-year Hodgkin lymphoma survivors (n=289). For 42 patients, cardiac contours were outlined on each patient's simulation X-ray by 4 different raters, and the mean heart dose was estimated as the percentage of the cardiac contour within the radiation field multiplied by the prescribed mediastinal dose and divided by a correction factor obtained by comparison with individual CT-based dosimetry. Results: According to the simulation X-ray method, the medians of the mean heart doses obtained from the cardiac contours outlined by the 4 raters were 30 Gy, 30 Gy, 31 Gy, and 31 Gy, respectively, following prescribed mediastinal doses of 25-42 Gy. The absolute-agreement intraclass correlation coefficient was 0.93 (95% confidence interval 0.85-0.97), indicating excellent agreement. Mean heart dose was 30.4 Gy with the simulation X-ray method, versus 30.2 Gy with the representative CT-based dosimetry, and the between-method absolute-agreement intraclass correlation coefficient was 0.87 (95% confidence interval 0.80-0.95), indicating good agreement between the two methods. Conclusion: Estimating mean heart dose from radiation therapy simulation X-rays is reproducible and fast, takes individual anatomy into account, and yields results comparable to the labor

Simulation study on unfolding methods for diagnostic X-rays and mixed gamma rays

International Nuclear Information System (INIS)

Hashimoto, Makoto; Ohtaka, Masahiko; Ara, Kuniaki; Kanno, Ikuo; Imamura, Ryo; Mikami, Kenta; Nomiya, Seiichiro; Onabe, Hideaki

2009-01-01

A photon detector operating in current mode that can sense X-ray energy distribution has been reported. This detector consists of a row of several segment detectors. The energy distribution is derived using an unfolding technique. In this paper, comparisons of the unfolding techniques among error reduction, spectrum surveillance, and neural network methods are discussed through simulation studies on the detection of diagnostic X-rays and gamma rays emitted by a mixture of 137 Cs and 60 Co. For diagnostic X-ray measurement, the spectrum surveillance and neural network methods appeared promising, while the error reduction method yielded poor results. However, in the case of measuring mixtures of gamma rays, the error reduction method was both sufficient and effective. (author)

Background of SAM atom-fraction profiles

International Nuclear Information System (INIS)

Ernst, Frank

2017-01-01

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition

Background of SAM atom-fraction profiles

Energy Technology Data Exchange (ETDEWEB)

Ernst, Frank

2017-03-15

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which is validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition.

Numerical simulation studies of the blowoff impulse induced by X-ray radiation in multilayer discontinuous material

International Nuclear Information System (INIS)

Tan Xiaoli; Ding Sheng

2010-01-01

In order to study the blowoff impulse induced by X-Ray radiation in new type compound material, the inhomogeneous reticular layers in a kind of multilayer discontinuous material were dealt with the equivalent method. So it could be simulated by method of continuum dynamics. The blowoff impulse in this material induced by irradiating of the blackbody spectral X-Ray was studied using numerical simulation method, and was compared with the result in LY-12Al. The changing discipline of the blowoff impulse along with the spectrum of X-Ray, the energy density and the type of material was analyzed. The main conclusions are: (1) the characteristic of energy deposition in material deciding by the spectrum of X-Ray is the ultimate cause of the magnitude of blowoff impulse; (2) for same spectrum and same material, higher energy density will cause more blowoff impulse, but the coupling coefficient of blowoff impulse is almost constant; (3) for same loading, the coupling coefficient of blowoff impulse of multilayer discontinuous material is bigger than that of LY-12Al. (authors)

Process of the x-ray image formation, (2). The limit to recognize a simple figure, (2)

Energy Technology Data Exchange (ETDEWEB)

Mitsuta, H [Osaka City Univ. (Japan). Hospital

1980-03-01

In recent year, X-ray photographs can be obtained by very low dose with high sensitivity photographic system. Such very low dose makes the image quality inferior because of the fluctuation of X-ray quanta so called ''quantum noise''. The process of the X-ray image formation was evaluated from a point of view that the X-ray images are formed by the accumulation of X-ray quanta distributed randomly. And the condition that the image of a simple-shaped small object can be recognized into background quanta was investigated. Under the assumption that the quanta absorbed by an object are N sub(s) and that the average number of background quanta per area which is in the same projected area of the object is N sub(b), the condition that N sub(s) is recognizable in background is mathematically led to the following formula: N sub(s) > 4(..sqrt..N sub(b) + 1). Then the validity of this formula was experimentally shown using a computer and a simulation system by a gamma camera.

On the maximal superalgebras of supersymmetric backgrounds

International Nuclear Information System (INIS)

Figueroa-O'Farrill, Jose; Hackett-Jones, Emily; Moutsopoulos, George; Simon, Joan

2009-01-01

In this paper we give a precise definition of the notion of a maximal superalgebra of certain types of supersymmetric supergravity backgrounds, including the Freund-Rubin backgrounds, and propose a geometric construction extending the well-known construction of its Killing superalgebra. We determine the structure of maximal Lie superalgebras and show that there is a finite number of isomorphism classes, all related via contractions from an orthosymplectic Lie superalgebra. We use the structure theory to show that maximally supersymmetric waves do not possess such a maximal superalgebra, but that the maximally supersymmetric Freund-Rubin backgrounds do. We perform the explicit geometric construction of the maximal superalgebra of AdS 4 X S 7 and find that it is isomorphic to osp(1|32). We propose an algebraic construction of the maximal superalgebra of any background asymptotic to AdS 4 X S 7 and we test this proposal by computing the maximal superalgebra of the M2-brane in its two maximally supersymmetric limits, finding agreement.