Sample records for radar cross-section rcs

  1. Radar cross sections of standard and complex shape targets

    NASA Technical Reports Server (NTRS)

    Sohel, M. S.

    1974-01-01

    The theoretical, analytical, and experimental results are described for radar cross sections (RCS) of different-shaped targets. Various techniques for predicting RCS are given, and RCS of finite standard targets are presented. Techniques used to predict the RCS of complex targets are made, and the RCS complex shapes are provided.

  2. Minimum radar cross section bounds for passive radar responsive tags

    Microsoft Academic Search

    P. Bidigare; T. Stevens; B Correll; M. Beauvais

    2004-01-01

    A common problem in ground moving target indication (GMTI) radar is detecting a target with even a large radar cross section (RCS) when its line-of-sight velocity falls below the minimum detectable velocity (MDV) for that radar system. In a cooperative scenario, a target may employ a tagging device, which can shift or spread its Doppler signature to become more detectable.

  3. Ultra wide band 3-D cross section (RCS) holography

    SciTech Connect

    Collins, H.D.; Hall, T.E.

    1992-07-01

    Ultra wide band impulse holography is an exciting new concept for predictive radar cross section (RCS) evaluation employing near-field measurements. Reconstruction of the near-field hologram data maps the target's scattering areas, and uniquely identifies the hot spot'' locations on the target. In addition, the target and calibration sphere's plane wave angular spectrums are computed (via digital algorithm) and used to generate the target's far-field RCS values in three dimensions for each frequency component in the impulse. Thin and thick targets are defined in terms of their near-field amplitude variations in range. Range gating and computer holographic techniques are applied to correct these variations. Preliminary experimental results on various targets verify the concept of RCS holography. The unique 3-D presentation (i.e., typically containing 524,288 RCS values for a 1024 {times} 512 sampled aperture for every frequency component) illustrates the efficacy of target recognition in terms of its far-field plane wave angular spectrum image. RCS images can then be viewed at different angles for target recognition, etc.

  4. Ultra wide band 3-D cross section (RCS) holography

    SciTech Connect

    Collins, H.D.; Hall, T.E.

    1992-07-01

    Ultra wide band impulse holography is an exciting new concept for predictive radar cross section (RCS) evaluation employing near-field measurements. Reconstruction of the near-field hologram data maps the target`s scattering areas, and uniquely identifies the ``hot spot`` locations on the target. In addition, the target and calibration sphere`s plane wave angular spectrums are computed (via digital algorithm) and used to generate the target`s far-field RCS values in three dimensions for each frequency component in the impulse. Thin and thick targets are defined in terms of their near-field amplitude variations in range. Range gating and computer holographic techniques are applied to correct these variations. Preliminary experimental results on various targets verify the concept of RCS holography. The unique 3-D presentation (i.e., typically containing 524,288 RCS values for a 1024 {times} 512 sampled aperture for every frequency component) illustrates the efficacy of target recognition in terms of its far-field plane wave angular spectrum image. RCS images can then be viewed at different angles for target recognition, etc.

  5. Application of Bionics in Antenna Radar Cross Section Reduction

    Microsoft Academic Search

    Wen Jiang; Ying Liu; Shuxi Gong; Tao Hong

    2009-01-01

    Bionics principle is applied to antenna radar cross section (RCS) reduction in this letter for the first time. To authenticate the method, a novel bionic ultrawideband (UWB) antenna is proposed by use of a model of insect tentacle. Its UWB-related radiation characteristics are simulated and experimentally verified. Monostatic RCS of an insect tentacle antenna (ITA) terminated with three different loads

  6. Estimating Radar Cross Section using Bayesian Image Restoration Richard O. Lane

    E-print Network

    Haddadi, Hamed

    Estimating Radar Cross Section using Bayesian Image Restoration Richard O. Lane QinetiQ Malvern-dimensional radar cross section (RCS) of a vehicle given a radar image of the vehicle. A Markov chain Monte Carlo, the method may be applied to any type of radar image such as those produced by a synthetic aperture radar

  7. High-frequency RCS of open cavities with rectangular and circular cross sections

    Microsoft Academic Search

    Hao Ling; Shung-Wu Lee; Ri-Chee Chou

    1989-01-01

    The radar cross-section (RCS) analysis of open-ended cavities with rectangular and circular cross sections is carried out using the waveguide modal approach and the shooting-and-bouncing ray (SBR) approach. For a cavity opening on the order of ten wavelengths or larger, the comparison between the two approaches is excellent. It is also observed that at lower frequencies the SBR results deviate

  8. Simulations of the radar cross section of a stealth aircraft

    Microsoft Academic Search

    Mauro A. Alves; Rafael J. Port; Mirabel C. Rezende

    2007-01-01

    The radar cross section (RCS) of a CAD model of the stealth bomber B-2 Spirit was simulated with the CADRCS software. Results from simulations with the aircraft model having a perfectly conducting surface and rotating about the yaw, pitch and roll axes are presented and compared with results of simulations where the surface of the model was covered with a

  9. A new approach to radar cross-section compact range

    NASA Astrophysics Data System (ADS)

    Harrison, T.

    1986-06-01

    A new concept in compact range antenna systems provides increased dynamic range and reflector efficiency of 50 to 70 percent. The technology is based on beam shaping concepts that have been applied to solve chamber coupling problems of present systems. The result is a substantial step forward in the test and design capabilities for ultra low radar cross-section (RCS) testing with available systems for targets up to 40 feet long.

  10. The radar cross section of dielectric disks

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.

    1984-01-01

    A solution is presented for the backscatter (monostatic) radar cross section of dielectric disks of arbitrary shape, thickness, and dielectric constant. The result is obtained by employing a Kirchhoff-type approximation to obtain the fields inside the disk. The internal fields induce polarization and conduction currents from which the scattered fields and the radar cross section can be computed. The solution for the radar cross section obtained in this manner will be shown to agree with known results in the special cases of normal incidence, thin disks, and perfect conductivity. It will also be shown that the solution can be written as a product of the reflection coefficient of an identically oriented slab times the physical optics solution for the backscatter cross section of a perfectly conducting disk of the same shape. This result follows directly from the Kirchhoff-type approximation without additional assumptions.

  11. Radar cross section measurements of complex targets (missile parts) in C-band in anechoic chamber

    Microsoft Academic Search

    Marcelo A. S. Miacci; Inácio M. Martin; Mirabel C. Rezende

    2007-01-01

    Assembly of an experimental setting necessary to measure the radar cross section (RCS) of simple and complex targets was accomplished in an anechoic chamber using an active noise suppression system, by using the C-band of frequencies (5.0 to 7.0 GHz). As results of this Brazilian pioneer work in the area of electromagnetic characterization, the diagrams of the radar cross section

  12. Studies of the dependence of the microwave radar cross section on ocean surface variables during the FASINEX experiment

    NASA Technical Reports Server (NTRS)

    Weissman, D. A.; Li, Fuk

    1988-01-01

    The ability of theoretical radar cross section (RCS) models to predict the absolute magnitude of the ocean radar cross section under a wide variety of sea and atmospheric conditions was studied using experimental data from the FASINEX Experiment. This consists of RCS data from a Ku-band scatterometer mounted on an aircraft (10 separate flights were conducted), a wide variety of atmospheric measurements (including stress) and sea conditions. Theoretical models are tested. Where discrepancies are observed, revisions are hypothesized and evaluated.

  13. Lunar Radar Cross Section at Low Frequency

    NASA Technical Reports Server (NTRS)

    Rodriguez, P.; Kennedy, E. J.; Kossey, P.; McCarrick, M.; Kaiser, M. L.; Bougeret, J.-L.; Tokarev, Y. V.

    2002-01-01

    Recent bistatic measurements of the lunar radar cross-section have extended the spectrum to long radio wavelength. We have utilized the HF Active Auroral Research Program (HAARP) radar facility near Gakona, Alaska to transmit high power pulses at 8.075 MHz to the Moon; the echo pulses were received onboard the NASA/WIND spacecraft by the WAVES HF receiver. This lunar radar experiment follows our previous use of earth-based HF radar with satellites to conduct space experiments. The spacecraft was approaching the Moon for a scheduled orbit perturbation when our experiment of 13 September 2001 was conducted. During the two-hour experiment, the radial distance of the satellite from the Moon varied from 28 to 24 Rm, where Rm is in lunar radii.

  14. A study of GEOS-3 terrain data with emphasis on radar cross section

    NASA Technical Reports Server (NTRS)

    Priester, R. W.

    1980-01-01

    Radar cross sections (RCS) of terrain are studied using GEOS 3 radar altimeter data. Maps of RCS for portions of four east coast states (U.S.A.) are presented and used to draw curves of RCS versus inland distance as measured from the land/sea interface. The results show RCS to decay approximately exponentially with inland distance. The GEOS 3 data are also used to develop curves of RCS seasonal variation for the same regions. Observed variations correlate strongly with local potential evaporation. Results also show that farming operations in the state of North Carolina are observable in the RCS data. A restricted method for determining surface roughness features from saturated average return waveforms for some types of terrain is developed. Sensor bias induced by receiver saturation for certain terrain returns is briefly discussed.

  15. Study and Optimization of Plasma-Based Radar Cross Section Reduction Using Three-Dimensional Computations

    Microsoft Academic Search

    Bhaskar Chaudhury; Shashank Chaturvedi

    2009-01-01

    The radar cross section (RCS) of a flat plate covered with a cold collisional inhomogeneous plasma has been studied using a 3-D finite-difference time-domain (FDTD) method for electromagnetics. Two problems have been considered. In problem 1, using experimentally reported plasma density profiles, we have observed some interesting features in the bistatic RCS and provided simple physical interpretations for some of

  16. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. The application is presented of the Finite Difference Time Domain (FDTD) technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and discussed.

  17. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. We present the application of the Finite Difference Time Domain (FDTD) Technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and disclosed.

  18. Radar Cross-Section Measurements of V22 Blade Tip with and without LLNL Tipcap Reflector

    SciTech Connect

    Poland, D; Simpson, R

    2000-07-01

    It is desired to quantify the effect, in terms of radar cross-section (RCS), of the addition of a small aluminum reflector to the end of the V22 blades. This reflector was designed and manufactured in order to facilitate blade lag measurements by the 95 GHz Lawrence Livermore National Laboratory (LLNL) Radar Blade Tracker (RBT) system. The reflector used in these measurements was designed and fabricated at LLNL and is pictured in Figure 1.

  19. A study of radar cross section measurement techniques

    Microsoft Academic Search

    Malcolm W. McDonald

    1986-01-01

    Past, present, and proposed future technologies for the measurement of radar cross section were studied. The purpose was to determine which method(s) could most advantageously be implemented in the large microwave anechoic chamber facility which is operated at the antenna test range site. The progression toward performing radar cross section measurements of space vehicles with which the Orbital Maneuvering Vehicle

  20. Accuracy Check of the PO with the Modified Surface-Normal Vectors for Radar Cross Section Analyses

    Microsoft Academic Search

    Nobutaka Omaki; Luis Rodriguez; Tetsu Shijo; Makoto Ando

    The diffraction error in the Physical Optics (PO) is well known. The Physical Theory of Diffraction (PTD) succeeded in correcting of the PO diffraction error. As another modification theory, we had already suggested modifying the definition of the surface-normal vectors in the PO currents. This novel method has quite and easy vector configuration in Radar Cross Section (RCS) analyses. This

  1. A higher-order finite element method for computing the radar cross section of bodies of revolution

    Microsoft Academic Search

    Eric Douglas Branch

    2001-01-01

    The finite element method (FEM) is used to compute the radar cross section (RCS) of bodies of revolution (BORs). The FEM described here uses scalar basis functions for the phi component of the field and vector basis functions for the transverse component of the field. Higher-order basis functions are used to improve the performance of the FEM code. The mesh

  2. A New Integrated Radar Cross Section Analysis Method for Penetration Aircraft

    Microsoft Academic Search

    Ying Li; Jun Huang; Zhanhe Liu; Sheng Hong

    2010-01-01

    The RCS analysis conclusions are important for aircraft stealth design and the existing RCS analysis method has some disadvantages, such as just using average RCS value as the basis. This paper reported a new integrated RCS analysis method for penetration aircraft. The research of investigating the characters of target RCS and the dynamic detecting characters of radar and radar network

  3. Parametric bicubic spline and CAD tools for complex targets shape modelling in physical optics radar cross section prediction

    NASA Astrophysics Data System (ADS)

    Delogu, A.; Furini, F.

    1991-09-01

    Increasing interest in radar cross section (RCS) reduction is placing new demands on theoretical, computation, and graphic techniques for calculating scattering properties of complex targets. In particular, computer codes capable of predicting the RCS of an entire aircraft at high frequency and of achieving RCS control with modest structural changes, are becoming of paramount importance in stealth design. A computer code, evaluating the RCS of arbitrary shaped metallic objects that are computer aided design (CAD) generated, and its validation with measurements carried out using ALENIA RCS test facilities are presented. The code, based on the physical optics method, is characterized by an efficient integration algorithm with error control, in order to contain the computer time within acceptable limits, and by an accurate parametric representation of the target surface in terms of bicubic splines.

  4. A planar near-field scanning technique for bistatic radar cross section measurements

    NASA Technical Reports Server (NTRS)

    Tuhela-Reuning, S.; Walton, E. K.

    1990-01-01

    A progress report on the development of a bistatic radar cross section (RCS) measurement range is presented. A technique using one parabolic reflector and a planar scanning probe antenna is analyzed. The field pattern in the test zone is computed using a spatial array of signal sources. It achieved an illumination pattern with 1 dB amplitude and 15 degree phase ripple over the target zone. The required scan plane size is found to be proportional to the size of the desired test target. Scan plane probe sample spacing can be increased beyond the Nyquist lambda/2 limit permitting constant probe sample spacing over a range of frequencies.

  5. A study of radar cross section measurement techniques

    NASA Astrophysics Data System (ADS)

    McDonald, Malcolm W.

    1986-11-01

    Past, present, and proposed future technologies for the measurement of radar cross section were studied. The purpose was to determine which method(s) could most advantageously be implemented in the large microwave anechoic chamber facility which is operated at the antenna test range site. The progression toward performing radar cross section measurements of space vehicles with which the Orbital Maneuvering Vehicle will be called upon to rendezvous and dock is a natural outgrowth of previous work conducted in recent years of developing a high accuracy range and velocity sensing radar system. The radar system was designed to support the rendezvous and docking of the Orbital Maneuvering Vehicle with various other space vehicles. The measurement of radar cross sections of space vehicles will be necessary in order to plan properly for Orbital Maneuvering Vehicle rendezvous and docking assignments. The methods which were studied include: standard far-field measurements; reflector-type compact range measurements; lens-type compact range measurement; near field/far field transformations; and computer predictive modeling. The feasibility of each approach is examined.

  6. A study of radar cross section measurement techniques

    NASA Technical Reports Server (NTRS)

    Mcdonald, Malcolm W.

    1986-01-01

    Past, present, and proposed future technologies for the measurement of radar cross section were studied. The purpose was to determine which method(s) could most advantageously be implemented in the large microwave anechoic chamber facility which is operated at the antenna test range site. The progression toward performing radar cross section measurements of space vehicles with which the Orbital Maneuvering Vehicle will be called upon to rendezvous and dock is a natural outgrowth of previous work conducted in recent years of developing a high accuracy range and velocity sensing radar system. The radar system was designed to support the rendezvous and docking of the Orbital Maneuvering Vehicle with various other space vehicles. The measurement of radar cross sections of space vehicles will be necessary in order to plan properly for Orbital Maneuvering Vehicle rendezvous and docking assignments. The methods which were studied include: standard far-field measurements; reflector-type compact range measurements; lens-type compact range measurement; near field/far field transformations; and computer predictive modeling. The feasibility of each approach is examined.

  7. Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

    SciTech Connect

    Huang, Xianjun, E-mail: xianjun.huang@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Hu, Zhirun [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Liu, Peiguo [College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-11-15

    This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

  8. Bistatic and Multistatic Radar: Surveillance, Countermeasures, and Radar Cross Sections. (Latest Citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The bibliography contains citations concerning the design, development, testing, and evaluation of bistatic and multistatic radar used in surveillance and countermeasure technology. Citations discuss radar cross sections, target recognition and characteristics, ghost recognition, motion image compensation, and wavelet analysis. Stealth aircraft design, stealth target tracking, synthetic aperture radar, and space applications are examined.

  9. Bistatic and Multistatic Radar: Surveillance, Countermeasures, and Radar Cross Sections. (Latest citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The bibliography contains citations concerning the design, development, testing, and evaluation of bistatic and multistatic radar used in surveillance and countermeasure technology. Citations discuss radar cross sections, target recognition and characteristics, ghost recognition, motion image compensation, and wavelet analysis. Stealth aircraft design, stealth target tracking, synthetic aperture radar, and space applications are examined.

  10. Radar cross-section of Earth surfaces measured by spaceborne precipitation radar (TRMM PR)

    Microsoft Academic Search

    M. Satake; H. Hanado; T. Kozu

    2000-01-01

    Normalized radar cross section of Earth's surfaces are investigated using surface reflectivity data measured by a spaceborne radar, the Precipitation Radar boarded on the Tropical Rainfall Measuring Mission (TRMM PR). Homogeneous surfaces larger than 220 km of the PR's observation swath are selected for the investigation site, including rain forests, oceans, and some land areas. `Surface Sigma-O' products of the

  11. Validation through comparison: Measurement and calculation of the bistatic radar cross section of a stealth target

    E-print Network

    Gürel, Levent

    of a stealth target L. Gu¨rel and H. BagcØ Department of Electrical and Electronics Engineering, Bilkent cross section (BRCS) values of a stealth airborne target are predicted by performing both scaled multipole method, stealth, RCS computations, RCS measurements Citation: Gu¨rel, L., H. BagcØ, J. C. Castelli

  12. CFD spinoff - Computational electromagnetics for radar cross section (RCS) studies

    NASA Technical Reports Server (NTRS)

    Shankar, Vijaya; Mohammadian, Alireza H.; Hall, William F.; Erickson, Roy

    1990-01-01

    A finite-volume discretization procedure derived from proven CFD methods is used to solve the conservation form of the time-domain Maxwell's equations, in order to compute EM scattering from layered objects. This time-domain approach handles both single-frequency/continuous wave and broadband-frequency/pulse incident excitation. Arbitrarily shaped objects are modeled by means of a body-fitted coordinate transformation; complex internal/external structures with many material layers are treated through the implementation of a multizone framework capable of handling any type of zonal boundary condition. Results are presented for various two- and three-dimensional problems.

  13. Volumetric radar cross section of single tree calculated from far-field S-band measurements

    SciTech Connect

    Hicks, M.J.

    1988-08-01

    Backscatter radar cross section per unit volume of a single tree was calculated from far-field S-band measurements of radar cross section. The measurements were made at the SCATTER facility at Sandia National Laboratories, Albuquerque, New Mexico. The trees measured were an 11-ft (3.4-m) Austrian pine and a 22-ft (6.7-m) budding Modesto ash. Radar cross section of the pine was also measured after the needles had been stripped from the tree. The mean radar cross section per unit volume of the pine was -12 dBsm/m/sup 3/; the absence of needles had no significant effect on this result. The mean radar cross section per unit volume of the Modesto ash was -18 dBsm/m/sup 3/. 4 refs., 19 figs.

  14. Parallel computation of Radar Cross Section of target with coatings

    Microsoft Academic Search

    Y. Yan; H. Zhao; Y. Zhang; X. W. Zhao; C. H. Liang; D. Garcia-Donoro; T. K. Sarkar

    2011-01-01

    This paper deals with the problem of RCS prediction of body with coatings using the method of Physical Optics (PO). In order to shorten the calculation time, this paper uses parallel computation mechanism which is based on MPI. The results show that it can effectively improve the calculation efficiency. Keywords—RCS; body with coatings; PO; MPI I. INTRODUCTION The significance of

  15. The relationship between the microwave radar cross section and both wind speed and stress: Model function studies using Frontal Air-Sea Interaction Experiment data

    NASA Technical Reports Server (NTRS)

    Weissman, David E.; Davidson, Kenneth L.; Brown, Robert A.; Friehe, Carl A.; Li, Fuk

    1994-01-01

    The Frontal Air-Sea Interaction Experiment (FASINEX) provided a unique data set with coincident airborne scatterometer measurements of the ocean surface radar cross section (RCS)(at Ku band) and near-surface wind and wind stress. These data have been analyzed to study new model functions which relate wind speed and surface friction velocity (square root of the kinematic wind stress) to the radar cross section and to better understand the processes in the boundary layer that have a strong influence on the radar backscatter. Studies of data from FASINEX indicate that the RCS has a different relation to the friction velocity than to the wind speed. The difference between the RCS models using these two variables depends on the polarization and the incidence angle. The radar data have been acquired from the Jet Propulsion Laboratory airborne scatterometer. These data span 10 different flight days. Stress measurements were inferred from shipboard instruments and from aircraft flying at low altitudes, closely following the scatterometer. Wide ranges of radar incidence angles and environmental conditions needed to fully develop algorithms are available from this experiment.

  16. A probabilistic methodology for radar cross section prediction in conceptual aircraft design

    NASA Astrophysics Data System (ADS)

    Hines, Nathan Robert

    System effectiveness has increasingly become the prime metric for the evaluation of military aircraft. As such, it is the decision maker's/designer's goal to maximize system effectiveness. Industry and government research documents indicate that all future military aircraft will incorporate signature reduction as an attempt to improve system effectiveness and reduce the cost of attrition. Today's operating environments demand low observable aircraft which are able to reliably take out valuable, time critical targets. Thus it is desirable to be able to design vehicles that are balanced for increased effectiveness. Previous studies have shown that shaping of the vehicle is one of the most important contributors to radar cross section, a measure of radar signature, and must be considered from the very beginning of the design process. Radar cross section estimation should be incorporated into conceptual design to develop more capable systems. This research strives to meet these needs by developing a conceptual design tool that predicts radar cross section for parametric geometries. This tool predicts the absolute radar cross section of the vehicle as well as the impact of geometry changes, allowing for the simultaneous tradeoff of the aerodynamic, performance, and cost characteristics of the vehicle with the radar cross section. Furthermore, this tool can be linked to a campaign theater analysis code to demonstrate the changes in system and system of system effectiveness due to changes in aircraft geometry. A general methodology was developed and implemented and sample computer codes applied to prototype the proposed process. Studies utilizing this radar cross section tool were subsequently performed to demonstrate the capabilities of this method and show the impact that various inputs have on the outputs of these models. The F/A-18 aircraft configuration was chosen as a case study vehicle to perform a design space exercise and to investigate the relative impact of shaping parameters on radar cross section. Finally, two unique low observable configurations were analyzed to examine the impact of shaping for stealthiness.

  17. On reconciling ground-based with spaceborne normalized radar cross section measurements

    E-print Network

    Baumgartner, F.; Munk, J.; Jezek, K. C.; Gogineni, Sivaprasad

    2002-02-01

    derive an expression for 27 48 as a function of antenna range and physical properties of the firn. Our relationship describes why differences in derived values for 27 48 occur between spaceborne and ground-based radar. Two sites (GITS and NASA... radar cross section 127 versus the antenna range 82 . Fig. 3. Comparison of 27 derived from ground-based versus spaceborne data at GITS and NASA-U. By definition, this ratio is less than unity, and hence the ground-based normalized radar cross section...

  18. Airborne measurements of the ocean's Ku?band radar cross?section at low incidence angles

    Microsoft Academic Search

    B. Chapron; D. Vandemark; F. C. Jackson

    1994-01-01

    Ocean backscatter data obtained with a Ku?band airborne radar are presented along with coincident altimeter and directional wave spectral estimates. These data were collected using one sensor, NASA's radar ocean wave spectrometer (ROWS). The measurements are compared with an electromagnetic scattering model for perfectly conducting Gaussian random surfaces. The normalized radar cross?section (NRCS) data cover those incidence angles (0–20°) where

  19. Validation through comparison: Measurement and calculation of the bistatic radar cross section of a stealth target

    Microsoft Academic Search

    L. Gürel; H. Bagci; J. C. Castelli; A. Cheraly; F. Tardivel

    2003-01-01

    Bistatic radar cross section (BRCS) values of a stealth airborne target are predicted by performing both scaled-model measurements and numerical simulations. In order to achieve the solution of large-scale electromagnetic problems in the numerical simulation environment, the fast multipole method (FMM) is implemented and used. The FMM has produced remarkably accurate results, in addition to its efficiency. The efficiency of

  20. Radar cross section measurements of a scale model of the space shuttle orbiter vehicle

    NASA Technical Reports Server (NTRS)

    Yates, W. T.

    1978-01-01

    A series of microwave measurements was conducted to determine the radar cross section of the Space Shuttle Orbiter vehicle at a frequency and at aspect angles applicable to re-entry radar acquisition and tracking. The measurements were performed in a microwave anechoic chamber using a 1/15th scale model and a frequency applicable to C-band tracking radars. The data were digitally recorded and processed to yield statistical descriptions useful for prediction of orbiter re-entry detection and tracking ranges.

  1. Comparing EM Models to RCS Measurements for Building-Penetration Radar

    SciTech Connect

    Fasenfest, B; Ueberschaer, R

    2007-05-18

    For the DARPA VisiBuilding program, SRI International and Lawrence Livermore National Laboratory are using a variety of electromagnetic (EM) simulation codes and measurement techniques to analyze how radar pulses interact with building structures and materials. Of primary interest is how interior wall and corner reflections are delayed, attenuated, and dispersed by the exterior wall materials. In this paper, we compare microwave frequency-domain radar cross section (RCS) chamber measurements of scale models of simple buildings to finite-element and finite-difference full-wave time-domain and ray-tracing models. The ability to accurately reconstruct the building from these models is compared with the reconstruction from chamber measurements. We observe that careful attention to the spatial sampling in the EM models is essential to achieving good reconstruction at the higher frequencies.

  2. Progress In Electromagnetics Research B, Vol. 23, 5568, 2010 A HYBRID METHOD FOR COMPUTING THE RCS OF

    E-print Network

    Myung, Noh-Hoon

    Progress In Electromagnetics Research B, Vol. 23, 55­68, 2010 A HYBRID METHOD FOR COMPUTING THE RCS cross section (RCS) of multiple wire scatterers with an arbitrary orientation. Foldy-Lax equations, the difficulty of estimating the radar cross section (RCS) of chaff fibers is that analysis region is wide

  3. Importance of the sea surface curvature to interpret the normalized radar cross section

    NASA Astrophysics Data System (ADS)

    Mouche, A. A.; Chapron, B.; Reul, N.; Hauser, D.; Quilfen, Y.

    2007-10-01

    Asymptotic models (small perturbation and small slope approximation at first-order, Kirchhoff approximation or two-scale model) used to predict the normalized radar cross section of the sea surface generally fail to reproduce in detail backscatter radar measurements. In particular, the predicted polarization ratio versus incidence and azimuth angles is not in agreement with experimental data. This denotes the inability of these standard models to fully take into account the roughness properties with respect to the sensor's configuration of measurement (frequency, incidence, and polarization). On the basis of particular assumptions, to decompose the scattered electromagnetic field between zones covered with freely propagating waves and others where roughness and slopes are enhanced, recent works were able to match observations. In this paper, we do not assume such a decomposition but study the latest improvements obtained in the field of approximate scattering theories of random rough surfaces using the local and resonant curvature approximations. These models are based on an extension of the Kirchhoff Approximation up to first order to relate explicitly the curvature properties of the sea surface to the polarization strength of the scattered electromagnetic field. Consistency with previous approaches is discussed. As shown, dynamically taking into account the sea surface curvature properties of the surface is crucial to better interpret normalized radar cross-section and polarization ratio sensitivities to both sensor characteristics and geophysical environment conditions. The proposed developments, termed the Resonant Curvature Approximation (RCA), are found to reproduce experimental data versus incidence angle and azimuth direction. The polarization sensitivity to the wind direction and incidence angle is largely improved. Finally, Gaussian statistical assumption adopted to derive the analytical expression of the normalized radar cross section is also discussed. In particular, the third-order cumulant function is shown to better reproduce the second-order up-/down-wind azimuth modulation. The proposed developments appear very promising for improvement of our understanding and analysis of both sea surface radar backscatter and Doppler signals.

  4. Dynamic RCS Estimation of Chaff Clouds

    E-print Network

    Myung, Noh-Hoon

    Dynamic RCS Estimation of Chaff Clouds DONG WOOK SEO HYUN-JAE NAM OH-JOON KWON NOH HOON MYUNG, Member, IEEE KAIST We analytically investigated electromagnetic wave propagation through chaff clouds (GEC) method, this information is used to calculate the radar cross section (RCS) of the chaff cloud

  5. Fabrication of Radar Absorbing Shells Made of Hybrid Composites and Evaluation of Radar Cross Section

    Microsoft Academic Search

    Woo-Kyun Jung; Sung-Hoon Ahn; Bierng-Chearl Ahn

    2005-01-01

    ** , Seoung-Bae Park ** and Myung-Shik Won *** ABSTRACT The avoidance of enemy's radar detection is very important issue in the modern electronic weapon system. Researchers have been studied to minimize reflected signals of radar. In this research, two types of radar absorbing structure (RAS), \\

  6. Relative RADAR cross section based feature identification with millimeter wave RADAR for outdoor SLAM

    Microsoft Academic Search

    E. Jose; M. D. Adams

    2004-01-01

    Millimeter wave RADARs are more robust than most other sensors used in outdoor autonomous navigation in that their performance is less affected by dust, fog, moderate rain or snow and ambient lighting conditions. Millimeter wave (MMW) RADAR differs from other range sensors as it can provide complete power returns for many points down range. Im addition, MMW RADAR has a

  7. Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22-26 GHz

    E-print Network

    Paris-Sud XI, Université de

    Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22 platform in the RCS (Radar Cross Section) measurement of vehicles at 22-26 GHz for automotive radar application. Across several measurement steps, we compare different RCS measurement results in order

  8. The Effects of Plasma Shield on the Radar Cross Section of a Generic Missile in UHF Band

    NASA Astrophysics Data System (ADS)

    Chung, Shen

    2011-10-01

    RF Stealth is the dominant technology in today's military aircraft, and most is achieved by shape design with a few reductions achieved by RAM, but most of these effects are only valid in X band. With the popularity of UHF radar again rising, the possibility of detecting a stealth object has increased due to resonance effect, and this is difficult to decrease with previous means due to the long wavelength. A plasma shield generated in front of an object may be suitable to alter the RCS in specific band without physically changing its shape. We examine the RCS of a generic missile in UHF band, and compared it with one with a cone-shape plasma generated in front of the missile. We find the plasma effectively changes the RCS of the missile, though not necessarily smaller. The RCS of the missile with the plasma shield is now dominated by the plasma instead of the missile. The RCS is a function of the size, shape, and density of the plasma shield. For higher frequency signals like the X band radar, it can still penetrate the plasma, and sees the original RCS of the missile. Due to the relatively lower UHF frequency, the plasma density needed is lower than one in X band and thus more practical to achieve.

  9. A model function for ocean radar cross sections at 14.6 GHz

    NASA Technical Reports Server (NTRS)

    Wentz, F. J.; Thomas, L. A.; Peteherych, S.

    1984-01-01

    The relationship between the ocean's normalized radar cross section (NRCS) at 14.6 GHz and the surface wind vector is derived using the 3 months of Seasat microwave scatterometer (SASS) measurements. The derivation is based on the statistics of the SASS observations, and no in situ measurements are required, other than a mean global wind speed, which comes from climatology. The frequency distribution of the global wind vectors observed by SASS is assumed to be a bivariate normal probability function. A NRCS model function is found that maps the assumed wind vector statistics into the observed SASS NRCS statistics. This function is compared with a NRCS model coming from the Joint Air Sea Interaction Experiment (JASIN) and with aircraft scatterometer measurements. The results indicate that the statistically derived NRCS model is an improvement over the JASIN model, which was based on a limited number of in situ anemometer measurements.

  10. Radar target recognition system using 3D mathematical model

    Microsoft Academic Search

    Yosuke Nakano; Yoshihisa Hara; Jun Saito; Yoshio Inasawa

    1998-01-01

    A target recognition system is described using 3-D mathematical models which simulate radar images. The simulated radar images are created from radar cross section (RCS) responses of the 3-D models and compared with measured target radar images. The 3-D models consist of several thousands facets, and one facet size is less than the radar resolution. An RCS response of each

  11. The RCS of Wire-type Scattering Structures Dong-wook Seo1

    E-print Network

    Myung, Noh-Hoon

    The RCS of Wire-type Scattering Structures Dong-wook Seo1 and Noh-Hoon Myung1 1 School works mainly utilized the method of moment (MoM) for predicting the radar cross section (RCS) of a large to minimize the calculation time. In this case, the total RCS of many wires is simply the product

  12. A Wireless Passive RCS-based Temperature Sensor using Liquid Metal and Microfluidics Technologies

    E-print Network

    Tentzeris, Manos

    A Wireless Passive RCS-based Temperature Sensor using Liquid Metal and Microfluidics Technologies by the change in radar cross section (RCS) of the device. Simulation and measurements of the backscattered power. For the first time the remote measurement of temperature based on the RCS variability of a microfluidics

  13. Improvement of RCS estimation of large targets by using near-field approach

    E-print Network

    Paris-Sud XI, Université de

    Improvement of RCS estimation of large targets by using near-field approach E. Gillion1,2 , E in order to estimate the Radar Cross Section (RCS) of large objects in their environments. Object. Simulations have been made in a frequency band between 1 to 20 GHz. Some simulated results of RCS estimation

  14. Normalized radar cross section of the sea for backscatter: 1. Mean levels

    NASA Astrophysics Data System (ADS)

    Plant, William J.; Keller, William C.; Hayes, Kenneth; Chatham, Gene

    2010-09-01

    The normalized radar cross section of the sea for backscatter, ?o, is investigated for incidence angles between 0° and 89° using data collected over more than two decades. The most recent measurements were made from several ships using a coherent, dual-polarized, X band radar. These measurements show that vertically polarized transmit and receive signals, ?o(VV), at high incidence angles exhibit wind speed and azimuth angle dependence similar to those at lower incidence angles. They are nearly as large looking downwind as they are looking upwind and minimize near the crosswind direction. Horizontally polarized transmit and receive signals, ?o (HH), behave differently at high incidence angles. They are largest looking upwind and smallest looking downwind. Fits of the multiscale model of microwave backscatter from the ocean to these data along with data collected previously at lower incidence angles show that over the whole range of incidence angles from 0° to 89°, ?o(VV) is explained by the model, while measured ?o(HH) values are generally higher than the model predicts at incidence angles above about 45°. Thus scattering phenomena exist on the ocean surface that affect HH backscatter very strongly at the higher incidence angles while impacting VV-polarized backscatter only slightly. This conclusion is strengthened by our observation of high-incidence-angle backscatter from the ocean where mean ?o(HH) exceeds mean ?o(VV) by as much as 15 dB. We examine phenomena that might account for this behavior and suggest that multipath dihedral-type features are likely to be important scatterers since they produce large ?o(HH)/?o(VV) owing to Brewster damping of the first VV bounce.

  15. The relationship between wind vector and normalized radar cross section used to derive Seasat-A Satellite Scatterometer winds

    NASA Technical Reports Server (NTRS)

    Schroeder, L. C.; Jones, W. L.; Boggs, D. H.; Halberstam, I. M.; Dome, G.; Pierson, W. J.; Wentz, F. J.

    1982-01-01

    The Seasat-A Satellite Scatterometer (SASS) ocean normalized radar cross section (NRCS) dependence on the 19.5-m neutral stability wind vector may be specified as a function of radar incidence angle, the angle between wind direction and radar azimuth, and the neutral stability wind speed expressed in m/sec at a height of 19.5 m. An account is given of the development of models both expressing this relationship and providing the basis of inversion of NRCS to SASS winds, from initially aircraft scatterometer measurement-based forms to three Seasat field-validation experiments which furnish model NRCS versus surface windspeed data for comparison with SASS data.

  16. RCS Analysis of Plate Geometries, parts 1 and 2

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1993-01-01

    High-frequency techniques for Radar Cross Section (RCS) prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors are addressed. In part 1, a Uniform Theory of Diffraction (UTD) model for the principal-plane radar cross section (RCS) of a perfectly conducting, rectangular plate coated on one side with an electrically thin, lossy dielectric is presented. In part 2, the scattering in the interior regions of both square and triangular trihedral corner reflectors are examined.

  17. Nonsinusoidal radar signal design for stealth targets

    Microsoft Academic Search

    Nasser J. Mohamed

    1995-01-01

    The detection of stealth point targets challenges the design of conventional radars using sinusoidal carriers since the objective of stealth technology is to reduce the radar cross section (RCS) of targets to a level where the radar receiver cannot detect the target. While there are a number of techniques employing different technologies to reduce the RCS of targets, shaping and

  18. Radar background signal reduction study

    Microsoft Academic Search

    E. F. Knott; C. J. Ray; M. S. West; R. J. Wohlers

    1980-01-01

    This report summarizes a study whose objective was to identify materials and\\/or techniques to reduce radar background signals for ground plane radar cross section (RCS) ranges. Background signal reduction is essential for improving the accuracy of RCS measurements and the primary application is for operations at the RATSCAT range on the White Sands Missile Range in New Mexico. A survey

  19. The estimation of pointing angle and normalized surface scattering cross section from GEOS-3 radar altimeter measurements

    NASA Technical Reports Server (NTRS)

    Brown, G. S.; Curry, W. J.

    1977-01-01

    The statistical error of the pointing angle estimation technique is determined as a function of the effective receiver signal to noise ratio. Other sources of error are addressed and evaluated with inadequate calibration being of major concern. The impact of pointing error on the computation of normalized surface scattering cross section (sigma) from radar and the waveform attitude induced altitude bias is considered and quantitative results are presented. Pointing angle and sigma processing algorithms are presented along with some initial data. The intensive mode clean vs. clutter AGC calibration problem is analytically resolved. The use clutter AGC data in the intensive mode is confirmed as the correct calibration set for the sigma computations.

  20. 3330 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 44, NO. 11, NOVEMBER 2006 Radar Scattering From a Rolling Target Floating on a

    E-print Network

    Burkholder, Robert J.

    , IEEE, and Robert J. Burkholder, Fellow, IEEE Abstract--The variations in the radar cross section (RCS on the RCS for low-grazing angles of incidence. The effect is very pronounced for a high-RCS shiplike target for a low-RCS shape. A simplified means of estimating the variation is also presented. Index Terms

  1. Simultaneous ocean cross-section and rainfall measurements from space with a nadir-pointing radar

    NASA Technical Reports Server (NTRS)

    Meneghini, R.; Atlas, D.

    1984-01-01

    A method to determine simultaneously the rainfall rate and the normalized backscattering cross section of the surface was evaluated. The method is based on the mirror reflected power, p sub m which corresponds to the portion of the incident power scattered from the surface to the precipitation, intercepted by the precipitation, and again returned to the surface where it is scattered a final time back to the antenna. Two approximations are obtained for P sub m depending on whether the field of view at the surface is either much greater or much less than the height of the reflection layer. Since the dependence of P sub m on the backscattering cross section of the surface differs in the two cases, two algorithms are given by which the path averaged rain rate and normalized cross section are deduced. The detectability of P sub m, the relative strength of other contributions to the return power arriving simultaneous with P sub m, and the validity of the approximations used in deriving P sub m are discussed.

  2. Assessment of orbital debris size estimation from radar cross-section measurements

    Microsoft Academic Search

    R. Lambour; N. Rajan; T. Morgan; I. Kupiec; E. Stansbery

    2004-01-01

    MIT Lincoln Laboratory has conducted a measurement program for man-made orbital debris since 1991 in response to NASA's need to characterize the orbital debris population and facilitate manned spaceflight activities. The primary sensors used in that effort are the Haystack and Haystack auxiliary (HAX) radars located at the Lincoln space surveillance complex (LSSC) in Westford, Massachusetts. This paper will describe

  3. Azimuthal Signature of Coincidental Brightness Temperature and Normalized Radar Cross-Section Obtained Using Airborne PALS Instrument

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; Kim, Seungbum; Yueh, Simon; Cosh, Mike; Jackson, Tom; Njoku, Eni

    2010-01-01

    Coincidental airborne brightness temperature (TB) and normalized radar-cross section (NRCS) measurements were carried out with the PALS (Passive and Active L- and S-band) instrument in the SMAPVEX08 (SMAP Validation Experiment 2008) field campaign. This paper describes results obtained from a set of flights which measured a field in 45(sup o) steps over the azimuth angle. The field contained mature soy beans with distinct row structure. The measurement shows that both TB and NRCS experience modulation effects over the azimuth as expected based on the theory. The result is useful in development and validation of land surface parameter forward models and retrieval algorithms, such as the soil moisture algorithm for NASA's SMAP (Soil Moisture Active and Passive) mission. Although the footprint of the SMAP will not be sensitive to the small resolution scale effects as the one presented in this paper, it is nevertheless important to understand the effects at smaller scale.

  4. Dismount modeling and detection from small aperture moving radar platforms

    Microsoft Academic Search

    R. K. Hersey; W. L. Melvin; E. Culpepper

    2008-01-01

    Future advanced radar systems must detect targets of diminishing radar cross section (RCS) at low radial velocity, in demanding clutter and interference environments. Presently, a deficiency in radar detection performance exists between the capabilities of synthetic aperture radar (SAR) for fixed target indication and space-time adaptive processing (STAP) for ground moving target indication (GMTI) of targets with low ground track

  5. Bistatic RCS of complex objects near forward scatter

    Microsoft Academic Search

    Jerome Glaser

    1985-01-01

    A technique is presented for predicting the bistatic radar cross section (RCS) of an opaque, arbitrarily shaped object at angles near forward scatter. Babinet's principle is employed to approximate the object's scattering pattern as the two-dimensional Fourier transform of its silhouette. Calculations for spheres and right-circular cylinders are shown to agree with predictions based on exact Mie theory, method of

  6. FMM Computation of the Bistatic RCS of Stealth and Nonstealth Targets

    E-print Network

    Gürel, Levent

    FMM Computation of the Bistatic RCS of Stealth and Nonstealth Targets L. Gürel* and H. Bagci, ranging from the design of novel stealth vehicles with reduced radar signatures to the decision of what radar cross section (BRCS) values of stealth and nonstealth airborne targets are predicted by performing

  7. RCS reduction of a microstrip patch using lumped loads

    NASA Technical Reports Server (NTRS)

    Volakis, John L.; Alexanian, Angelos

    1992-01-01

    In this report we consider the radar cross section (RCS) of a single rectangular patch antenna in a recessed cavity. Using a previously developed finite element-boundary integral method code, a study is performed on the patch's RCS as a function of frequency. To reduce the RCS of the patch at the resonant frequency, lumped (resistive) loads are placed at the edges of the patch. The effects of the lumped loads on the patch's RCS and gain are examined and it is observed that the RCS and gain are reduced as the as the load value decreases, whereas the antenna's bandwidth is increased. At resonance, the usual relations between the RCS and gain is observed, but it is shown that this relation no longer holds at frequencies away from resonance.

  8. Dependence of the Normalized Radar Cross Section of Water Waves on Bragg Wavelength-Wind Speed Sensitivity

    NASA Technical Reports Server (NTRS)

    Long, David G.; Collyer, R. Scott; Reed, Ryan; Arnold, David V.

    1996-01-01

    Measurements of the normalized radar cross section (sigma(sup o)) made by the YSCAT ultrawideband scatterometer during an extended deployment on the Canada Centre for Inland Waters(CCIW) Research Tower located at Lake Ontario are analyzed and compared with anemometer wind measurements to study the sensitivity of (sigma(sup o)) to the wind speed as a function of the Bragg wavelength. This paper concentrates on upwind and downwind azimuth angles in the wind speed range of 4.5-12 m/s. While YSCAT collected measurements of sigma(sup o) at a variety of frequencies and incidence angles, this paper focuses on frequencies of 2.0, 3.05, 5.30, 10.02, and 14.0 GHz and incidence angles within the Bragg regime, 30-50 deg. Adopting a power law model to describe the relationship between sigma(sup o) and wind speed, both wind speed exponents and upwind/downwind (u/d) ratios of sigma(sup o) are found using least squares linear regression. The analysis of the wind speed exponents and u/d ratios show that shorter Bragg wavelengths (Lambda less than 4 cm) are the most sensitive to wind speed and direction. Additionally, vertical polarization (V-pol) sigma(sup o) is shown to be more sensitive to wind speed than horizontal polarization (H-pol) sigma(sup o), while the H-pol u/d ratio is larger than the V-pol u/d ratio.

  9. Near-Nadiral Normalized Radar Cross Section of the SEA Surface at Ku, Ka, and W-Bands: Comparison of Measurements and Models

    NASA Technical Reports Server (NTRS)

    Majurec, Ninoslav; Johnson, Joel T.; Tanelli, Simone; Durden, Stephen

    2012-01-01

    Understanding the relationship between wind speed and direction and the near-nadiral normalized radar cross section (NRCS) of the sea surface is important in many oceanographic and atmospheric remote sensing applications: (1) wind speed retrievals in traditional altimeter systems (2) assistance in calibration and path integrated attenuation processing for atmospheric profiling radars The desired wind speed (and direction in some cases) retrieval requires a clear understanding of the relationship between the relevant geophysical quantities and the observed NRCS Such understanding is available from existing electromagnetic models, but the presence of many such models, as well as implicit descriptions of the sea surface, motivates continued evaluation of model performance.

  10. GRECO: graphical electromagnetic computing for RCS prediction in real time

    Microsoft Academic Search

    Juan M. Rius; M. Ferrando; L. Jofre

    1993-01-01

    An innovative approach to computing the high-frequency radar cross sections (RCSs) of complex radar targets in real time, using a 3-D graphics workstation, is presented. The target (typically, an aircraft) is modeled with the I-IDEAS solid-modeling software, using a parametric-surface approach. The high-frequency RCS is obtained through physical optics (PO), the method of equivalent currents (MEC), the physical theory of

  11. STAP with medium PRF mode for non-side-looking airborne radar

    Microsoft Academic Search

    Yong-Liang Wang; Zheng Bao; Ying-Ning Peng

    2000-01-01

    Space-time adaptive processing (STAP) has been widely discussed for airborne radar systems to improve the system performance of detecting targets. This is especially true for airborne early warning (AEW) radar, which should find long-range and small radar cross section (RCS) targets such as the stealth aircraft and missiles. However, in existing airborne radar literature, STAP is mainly considered for clutter

  12. An Efficient Algorithm for Calculating Aircraft RCS Based on the Geometrical Characteristics

    Microsoft Academic Search

    Gao Zhenghong; Wang Mingliang

    2008-01-01

    Taking into account the influences of scatterer geometrical shapes on induced currents, an algorithm, termed the sparse-matrix method (SMM), is proposed to calculate radar cross section (RCS) of aircraft configuration. Based on the geometrical characteristics and the method of moment (MOM), the SMM points out that the strong current coupling zone could be predefined according to the shape of scatterers.

  13. A 524 GHZ POLARIMETRIC COMPACT RANGE FOR SCALE MODEL RCS MEASUREMENTS

    E-print Network

    Massachusetts at Lowell, University of

    over a desired set of target aspect and depression angles. A flat disk and a dihedral at two seam technology continues to evolve, the availability of high quality, radar cross section (RCS) data is essential-Wave Technology Laboratory (STL) at UMass Lowell has developed several compact ranges which specialize in using

  14. Shooting and bouncing rays - Calculating the RCS of an arbitrarily shaped cavity

    Microsoft Academic Search

    Hao Ling; Ri-Chee Chou; Shung-Wu Lee

    1989-01-01

    A ray-shooting approach is presented for calculating the interior radar cross section (RCS) from a partially open cavity. In the problem considered, a dense grid of rays is launched into the cavity through the opening. The rays bounce from the cavity walls based on the laws of geometrical optics and eventually exit the cavity via the aperture. The ray-bouncing method

  15. Radar sensors based on communication low Earth orbiting satellites microwave emission

    Microsoft Academic Search

    C. Mikhail; K. Kurt; N. David

    2000-01-01

    The test results confirmed the possibility of air target detection using microwave energy generated by LEOS (low Earth orbit satellites). The authors' results also could be supported by theoretical power budget evaluation. Taking into account, that the radar cross section corresponds in the authors' case to the bistatic RCS (for traditional air targets that RCS is 10-20 dB larger than

  16. The ogive as a RCS compact range standard

    NASA Technical Reports Server (NTRS)

    Dominek, A.; Nguyen, T.

    1989-01-01

    E- and H-plane radar cross section (RCS) patterns at 4 and 10 GHz are provided (based upon moment method calculations) for a perfectly conducting ogive to be used as a compact range verification standard. The dimensions of the ogive are 36 in. and 9.546 in. long with half tip angles of 15 deg and 20 deg, respectively. Comparison between the calculations and measurements are also provided.

  17. Combined Wind Vector and Sea State Impact on Ocean Nadir-Viewing Ku- and C-Band Radar Cross-Sections

    PubMed Central

    Tran, Ngan; Chapron, Bertrand

    2006-01-01

    The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Ku- and C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at higher winds. These results extend, for the first time, recent theoretical improved scattering approximation, and point some similarities between scattering and emission mechanisms at nadir. The observed directional effect can thus be interpreted as a signature of the curvature anisotropy of wind-generated short-scale waves. Sensitivities to both wind speed and sea state are also reported in the present analysis.

  18. Implementation of an Active Noise Cancellation System in RCS Measurements of Complex Targets in the C Band using an Anechoic Chamber

    Microsoft Academic Search

    Marcelo A. S. Miacci; Inácio Malmonge Martin; Mirabel C. Rezende

    This work presents the improvement design of a Radar Cross Section (RCS) measurement system of complex shapes targets (missiles), with the development of an active noise cancellation system. The RCS measurements were carried out in indoor ambient, in a quasi-monostatic condition, using an anechoic chamber, in the frequency range of 5.8 to 6.4 GHz (C-band). Experimental results of missile section

  19. NEUTRON CROSS SECTIONS

    Microsoft Academic Search

    Donald J. Hughes; R. B. Schwartz

    1958-01-01

    The material in the first edition of BNL-325 and its addendum, the ; supplement, and new data received up to May, 1958 are included. Thermal cross ; sections, resonance parameters, and cross section curves are given. (M.H.R.)

  20. High-frequency techniques for RCS prediction of plate geometries

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.

    1991-01-01

    Several different high-frequency methods for modeling the radar cross sections (RCSs) of plate geometries are examined. The Method of Equivalent Currents and a numerically derived corner diffraction coefficient are used to model the RCS of a rectangular, perfectly conducting plate in nonprincipal planes. The Uniform Theory of Diffraction is used to model the RCS of a rectangular, perfectly conducting plate in principal planes. For the soft polarization case, first-order and slope-diffraction terms are included. For the hard polarization case, up to four orders of diffraction are included. Finally, the Uniform Theory of Diffraction for impedance wedges and the Impedance Boundary Condition are used to model the RCS of a coated, rectangular plate in principal planes. In most of the cases considered, comparisons are made between theoretical and experimental results.

  1. Simulation assessment of RCS-aided multiple target tracking

    NASA Astrophysics Data System (ADS)

    Dunham, Darin T.; Ehrman, Lisa M.; Blair, W. Dale; Frost, Susan A.

    2007-09-01

    Closely-spaced (but resolved) targets pose a significant challenge for single-frame unique measurement-to-track data association algorithms. This is due to the similarity of the Mahalanobis distances between the closely-spaced measurements and tracks. Contrary to conventional wisdom, adding target feature information (e.g., target amplitude) does not necessarily improve the probability of correctly assigning measurements to tracks. In this paper, the theoretical limitations of using radar cross section (RCS) data to aid in measurement-totrack association are reviewed. The results of a high-fidelity simulation assessment of the benefits of RCSaided measurement-to-track association (using the Signal-to-Noise Ratio) are given and other possibilities for RCS-aided tracking are discussed. Namely, we show the analytical results of our investigation into using RCS information to determine the presence of merged measurements.

  2. Scattering Cross Section of Sound Waves by the Modal Element Method

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.; Kreider, Kevin L.

    1994-01-01

    #he modal element method has been employed to determine the scattered field from a plane acoustic wave impinging on a two dimensional body. In the modal element method, the scattering body is represented by finite elements, which are coupled to an eigenfunction expansion representing the acoustic pressure in the infinite computational domain surrounding the body. The present paper extends the previous work by developing the algorithm necessary to calculate the acoustics scattering cross section by the modal element method. The scattering cross section is the acoustical equivalent to the Radar Cross Section (RCS) in electromagnetic theory. Since the scattering cross section is evaluated at infinite distance from the body, an asymptotic approximation is used in conjunction with the standard modal element method. For validation, the scattering cross section of the rigid circular cylinder is computed for the frequency range 0.1 is less than or equal to ka is less than or equal to 100. Results show excellent agreement with the analytic solution.

  3. Determination of radar MTF

    SciTech Connect

    Chambers, D. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The ultimate goal of the Current Meter Array (CMA) is to be able to compare the current patterns detected with the array with radar images of the water surface. The internal wave current patterns modulate the waves on the water surface giving a detectable modulation of the radar cross-section (RCS). The function relating the RCS modulations to the current patterns is the Modulation Transfer Function (MTF). By comparing radar images directly with co-located CMA measurements the MTF can be determined. In this talk radar images and CMA measurements from a recent experiment at Loch Linnhe, Scotland, will be used to make the first direct determination of MTF for an X and S band radar at low grazing angles. The technical problems associated with comparing radar images to CMA data will be explained and the solution method discussed. The results suggest the both current and strain rate contribute equally to the radar modulation for X band. For S band, the strain rate contributes more than the current. The magnitude of the MTF and the RCS modulations are consistent with previous estimates when the wind is blowing perpendicular to the radar look direction.

  4. High-frequency techniques for RCS prediction of plate geometries

    NASA Astrophysics Data System (ADS)

    Balanis, Constantine A.; Polka, Lesley A.

    1993-07-01

    A Uniform Theory of Diffraction (UTD) model for the principal-plane radar cross section (RCS) of a perfectly conducting, rectangular plate coated on one side with an electrically thin (t much less than lambda), lossy dielectric is presented. The incorporation of higher-order, multiple diffractions and of multiply diffracted surface-waves is discussed in detail. It is demonstrated that these terms are crucial to obtaining an accurate model. Approximations that are used in the model are discussed. Suggestions for improvements to the model are made. Validation is provided via comparison with experimental data and a physical optics (PO) model.

  5. Geologic Cross Sections

    NSDL National Science Digital Library

    Sharon Browning

    For this project, students must select a several hundred kilometer long section of Earth's surface, ideally crossing one or more major plate boundaries and research all major tectonic events to construct a cross section. Students should also take into account other factors like age of the ocean floor, average elevation and gravity anomalies across their area. The purpose is to demonstrate the geologic/tectonic history of their cross section and present it in a clear, concise summary.

  6. Using a Kernel Adatron for Object Classification with RCS Data

    E-print Network

    Byl, Marten F; Rietman, Edward A

    2010-01-01

    Rapid identification of object from radar cross section (RCS) signals is important for many space and military applications. This identification is a problem in pattern recognition which either neural networks or support vector machines should prove to be high-speed. Bayesian networks would also provide value but require significant preprocessing of the signals. In this paper, we describe the use of a support vector machine for object identification from synthesized RCS data. Our best results are from data fusion of X-band and S-band signals, where we obtained 99.4%, 95.3%, 100% and 95.6% correct identification for cylinders, frusta, spheres, and polygons, respectively. We also compare our results with a Bayesian approach and show that the SVM is three orders of magnitude faster, as measured by the number of floating point operations.

  7. Full wave solutions for rough-surface bistatic radar cross sections: Comparison with small perturbation, physical optics, numerical, and experimental results

    Microsoft Academic Search

    Ezekiel Bahar; Bom Son Lee

    1994-01-01

    In this paper, full wave solutions are derived for the like- and cross-polarized electromagnetic fields diffusely scattered by two-dimensional rough surfaces. These expressions for the diffuse scattered fields are used to obtain the random rough-surface cross sections. The rough surface is characterized by a Gaussian joint probability density function for the surface heights and slopes at two points. These full

  8. RCS analysis and reduction for lossy dihedral corner reflectors

    NASA Technical Reports Server (NTRS)

    Griesser, Timothy; Balanis, Constantine A.; Liu, Kefeng

    1989-01-01

    The radar-cross-section (RCS) patterns of lossy dihedral corner reflectors are calculated, using a uniform geometrical theory of diffraction for impedance surfaces. All terms of up to third-order reflections and diffractions are considered for patterns in the principal plane. The surface waves are included whenever they exist for reactive surface impedances. The dihedral corner reflectors examined have right, obtuse, and acute interior angles, and patterns over the entire 360 deg azimuthal plane are calculated. The surface impedances can be different on the four faces of the dihedral corner reflector; however, the surface impedance must be uniform over each face. Computed cross sections are compared with the results of a moment-method technique for a dielectric/ferrite absorber coating on a metallic corner reflector.

  9. Application of Model Based Parameter Estimation for RCS Frequency Response Calculations Using Method of Moments

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.

    1998-01-01

    An implementation of the Model Based Parameter Estimation (MBPE) technique is presented for obtaining the frequency response of the Radar Cross Section (RCS) of arbitrarily shaped, three-dimensional perfect electric conductor (PEC) bodies. An Electric Field Integral Equation (EFTE) is solved using the Method of Moments (MoM) to compute the RCS. The electric current is expanded in a rational function and the coefficients of the rational function are obtained using the frequency derivatives of the EFIE. Using the rational function, the electric current on the PEC body is obtained over a frequency band. Using the electric current at different frequencies, RCS of the PEC body is obtained over a wide frequency band. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth. Good agreement between MBPE and the exact solution over the bandwidth is observed.

  10. Application of AWE for RCS Frequency Response Calculations Using Method of Moments

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.

    1996-01-01

    An implementation of the Asymptotic Waveform Evaluation (AWE) technique is presented for obtaining the frequency response of the Radar Cross Section (RCS) of arbitrarily shaped, three-dimensional perfect electric conductor (PEC) bodies. An Electric Field Integral Equation (EFIE) is solved using the Method of Moments (MoM) to compute the RCS. The electric current, thus obtained, is expanded in a Taylor series around the frequency of interest. The coefficients of the Taylor series (called 'moments') are obtained using the frequency derivatives of the EFIE. Using the moments, the electric current on the PEC body is obtained over a frequency band. Using the electric current at different frequencies, RCS of the PEC body is obtained over a wide frequency band. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth. A good agreement between AWE and the exact solution over the bandwidth is observed.

  11. NEUTRON ACTIVATION CROSS SECTIONS

    Microsoft Academic Search

    J. A. Miskel; K. V. Marsh; M. Lindner; R. J. Nagle

    1959-01-01

    The (n, ) activation cross sections of several nuclides were measured ; as a function of neutron energy. The neutron energy range covered was from 31 ; kev to 6 Mev. The nuclides studied were Hf¹⁸°, Ta¹⁸¹,W¹⁸⁶,Au\\/; sup 197\\/, and Th\\/sup 232. (auth)

  12. Cross Section Flyer

    NSDL National Science Digital Library

    2011-03-16

    In this activity, students use slider bars to move a cross section of a cone, cylinder, prism, or pyramid. This activity allows students to explore conic sections and the 3-dimensional shapes from which they are derived. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

  13. Forward scatter RCS estimation for ground targets

    Microsoft Academic Search

    V. I. Sizov; M. Cherniakov; M. Antoniou

    2007-01-01

    Computer simulation models and techniques are proposed for RCS estimation of ground targets in a forward scattering micro radar network. A number of practical targets are considered as simulation examples over a wide range of radar carrier frequencies.

  14. Thermal Neutron Activation Cross Sections

    Microsoft Academic Search

    Leo Seren; Herbert N. Friedlander; Solomon H. Turkel

    1947-01-01

    The activation method of measuring slow neutron cross sections is discussed, in connection with the survey made at Argonne Laboratory. A table is given listing 131 activation cross sections of 65 elements and properties of the radio isotopes produced.

  15. DSI3D - RCS user manual

    SciTech Connect

    Madsen, N.; Steich, D.; Cook, G. [and others

    1995-08-23

    The DSI3D-RCS code is designed to numerically evaluate radar cross sections on complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D-RCS code is unique for the following reasons: Allows the use of unstructured non-orthogonal grids, allows a variety of cell or element types, reduces to be the Finite Difference Time Domain (FDTD) method when orthogonal grids are used, preserves charge or divergence locally (and globally), is conditionally stable, is selectively non-dissipative, and is accurate for non-orthogonal grids. This method is derived using a Discrete Surface Integration (DSI) technique. As formulated, the DSI technique can be used with essentially arbitrary unstructured grids composed of convex polyhedral cells. This implementation of the DSI algorithm allows the use of unstructured grids that are composed of combinations of non-orthogonal the use of unstructured grids that are composed of combinations of non-orthogonal hexahedrons, tetrahedrons, triangular prisms and pyramids. This algorithm reduces to the conventional FDTD method when applied on a structured orthogonal hexahedral grid.

  16. The design of broadband radar absorbing surfaces

    NASA Astrophysics Data System (ADS)

    Suk, Go H.

    1990-09-01

    There has been a growing and widespread interest in radar absorbing material technology. As the name implies, radar absorbing materials or RAM's are coatings whose electric and magnetic properties have been selected to allow the absorption of microwave energy at discrete or broadband frequencies. In military applications low radar cross section (RCS) of a vehicle may be required in order to escape detection while a covert mission is being carried on. These requirements have led to the very low observable or stealth technology that reduces the probability of detection of an aircraft. The design of radar absorbing materials is limited by constraints on the allowable volume and weight of the surface coating, and it is difficult to design a broadband radar absorbing structure in limited volume. This thesis investigates the use of lossy dielectric materials of high dielectric permittivity in multilayer composites for the production of low radar cross section (RCS). The analysis is done by computing the plane wave reflection coefficient at the exterior surface of the composite coating by means of a computer program which selects layer parameters which determine low reflection coefficients for electromagnetic radiation under constraint of limited layer thickness as well as maximum frequency bandwidth.

  17. Stray signal requirements for compact range reflectors based on RCS measurement errors

    NASA Technical Reports Server (NTRS)

    Lee, Teh-Hong; Burnside, Walter D.

    1991-01-01

    The authors present a performance criterion for compact range reflectors such that their edge diffracted stray signal levels meet a reasonable radar cross section (RCS) measurement error requirement. It is shown by example that one of the significant error sources is the diffracted fields emanating from the edges or junctions of the reflector. This measurement error is demonstrated by placing a diagonal square flat plate in the target zone and rotating it to appropriate angles. These angles are determined by bisecting the plane wave and stray signal directions. This results in a peak bistatic measurement of the edge diffracted stray signal. It is proposed that the diagonal flat plate be used to evaluate new reflector designs as well as existing systems. A reasonable stray signal performance level has been developed so that new reflector systems can be characterized in terms of an RCS measurement error requirement.

  18. High-frequency bistatic cross sections of the ocean surface

    Microsoft Academic Search

    E. W. Gill; J. Walsh

    2001-01-01

    An analysis leading to the first- and second-order bistatic cross sections of the ocean surface in the context of high-frequency ground wave radar operation is presented. Initially, a pulsed dipole source is introduced into the previously derived electric field expressions for the bistatic reception of vertically polarized radiation scattered from rough surfaces that do not vary with time. To make

  19. ABSORPTION CROSS SECTION OF STABLE, LOW CROSS SECTION FISSION PRODUCTS

    Microsoft Academic Search

    Breslauer

    1959-01-01

    A record of the relatively stable, low cross section fissibn products ; available on ANP nuclear data tape is presented for conventional reactor ; calculations. The record is based on data included in the Geneva conference ; paper by Gordeev and Pupko. The label slag is applied to fission products. ; (J.R.D.);

  20. NEUTRON-ACTIVATION CROSS SECTIONS

    Microsoft Academic Search

    J. A. Miskel; K. V. Marsh; M. Lindner; R. J. Nagle

    1961-01-01

    Neutron-activation cross sections for Hf¹⁸°, Ta¹⁸¹, W\\/sup ; 186\\/ Au¹⁹⁷, and Th²³² were measured. The results were compared ; with those calculated using the statistical theory of nuclear reactions and with ; resuits obtained by other investigators. (J.R.D.);

  1. DSI3D-RCS test case manual

    SciTech Connect

    Madsen, N.; Steich, D.; Cook, G.; Eme, B.

    1995-08-01

    The DSI3D-RCS code is designed to numerically evaluate radar cross sections on complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D-RCS code has been used to solve the following problems: (1) wedge cylinder--thin flat metal plate; (2) wedge cylinder with plate extension--thin flat metal plate; (3) plate with half cylinder extension--thin flat metal plate; (4) rectangular plate (business card)--thin flat metal plate; (5) wedge cylinder with gap--thin flat metal plate; (6) NASA Almond; (7) wavelength circular cavity. In order to generate each of the angle sweeps, it was necessary to run DSI3D once for each data point on the graphs. This is because these are backscatter calculations, and the incident pulse comes from a different direction as the angle {phi} is changed.

  2. FISSION-PRODUCT CAPTURE CROSS SECTIONS

    Microsoft Academic Search

    J. D. Garrison; B. W. Roos

    1962-01-01

    Experimental measurements of fission product capture cross sections and ; statistical estimates of capture cross sections for energies at which no ; measurements have been made yielded a set of group cross sections for primary and ; secondary fission products covering the complete range of energies of interest ; for reactor calculations. Capture cross sections and fission product yield ;

  3. Radar scattering from foamed plastic target supports

    NASA Astrophysics Data System (ADS)

    Chambers, Michael W.

    1991-12-01

    This study investigates the scattering from foamed plastic target supports. This material is often used in both indoor and outdoor ranges to support all sizes of targets for radar cross section measurements. Two common foamed plastics, styrofoam and expanded bead polystyrene (EPS), are discussed. Two types of scattering are associated with foamed plastic, coherent and incoherent. The incoherent is normally the lowest, but has not been satisfactorily quantified. Coherent scattering is related to the shape of the target, and the emphasis of this study is on the coherent return. One goal was to predict the coherent RCS of an EPS column using the Uniform Theory of Diffraction (UTD). It was found that UTD can accurately predict the backscatter of an EPS column consisting of flat and curved surfaces. The second goal was to experimentally study the effects of shaping on coherent RCS. The benefits of adding a vertical slope to circular cylindrical columns was studied. RCS reductions of approximately 20 dB were achieved. Some low RCS column shapes were also measured; sloping did not produce a measurable RCS reduction in these cases.

  4. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1993-01-01

    Part 1 of this report continues the investigation, initiated in previous reports, of scattering from rectangular plates coated with lossy dielectrics. The hard polarization coefficients given in the last report are incorporated into a model, which includes second- and third-order diffractions, for the coated plate. Computed results from this model are examined and compared to measured data. A breakdown of the contribution of each of the higher-order terms to the total radar cross section (RCS) is given. The effectiveness of the uniform theory of diffraction (UTD) model in accounting for the coating effect is investigated by examining a Physical Optics (PO) model which incorporates the equivalent surface impedance approximation used in the UTD model. The PO, UTD, and experimental results are compared. Part 2 of this report presents a RCS model, based on PO and the Method of Equivalent Currents (MEC), for a trihedral corner reflector. PO is used to account for the reflected fields, while MEC is used for the diffracted fields. Single, double, and triple reflections and first-order diffractions are included in the model. A detailed derivation of the E(sub theta)-polarization, monostatic RCS is included. Computed results are compared with finite-difference time-domain (FDTD) results for validation. The PO/MEC model of this report compares very well with the FDTD model, and it is a much faster model in terms of computational speed.

  5. Forward scattering radiolocation bistatic RCS and target detection

    Microsoft Academic Search

    A. B. Blyakhman; I. A. Runova

    1999-01-01

    The analytical and experimental studies of radar cross-section of air objects during bistatic forward scattering radiolocation were undertaken. The detection zones of a bistatic forward scattering radar were analytically estimated and compared to those obtained during field test

  6. Target Tracking Using Monopulse MIMO Radar With Distributed Antennas

    E-print Network

    Nehorai, Arye

    cross section (RCS) of the target. This RCS varies with the angle of view of the target. We can exploit from different angles simultaneously, the angles which result in a low RCS value are compensated by the others which have a higher RCS, thereby leading to an overall improve- ment in the performance

  7. LUMEN Cross-Section Tutorial

    NSDL National Science Digital Library

    McNulty, John A.

    The Loyola University Medical Education Network (LUMEN) presents this anatomy tutorial. The site is divided up into categories of cross-sectional images of the human body: Head and Neck, Upper Limb, male and female Thorax, Abdomen, male and female Pelvis, and Lower Limb. By clicking on each section, users select a cross-section of that part of the anatomy, and by clicking on each number, can find out the specific name of that area. Users can also choose to see an illustration of the area (by choosing â??Imageâ?), or an image from a CAT scan (by choosing â??CTâ?). This is an excellent resource for students in any health care or allied medical field, including nursing or nursesâ?? aides, patient care assistants, and diagnostic imaging technicians.

  8. Neutron-Activation Cross Sections

    Microsoft Academic Search

    J. A. Miskel; K. V. Marsh; M. Lindner; R. J. Nagle

    1962-01-01

    Neutron-activation cross sections have been measured for five target nuclei, Hf180, Ta181, W186, Au197, and Th232, over a neutron energy range from 0.030 to 4.0 MeV. The experimental results are compared with values calculated from the statistical theory of nuclear reactions. Values of the constant Cn in the approximate level density formula pn=Cnexp[2(aE)12] are obtained for these isotopes from a

  9. Electron-Impact Ionization Cross Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 107 Electron-Impact Ionization Cross Section Database (Web, free access)   This is a database primarily of total ionization cross sections of molecules by electron impact. The database also includes cross sections for a small number of atoms and energy distributions of ejected electrons for H, He, and H2. The cross sections were calculated using the Binary-Encounter-Bethe (BEB) model, which combines the Mott cross section with the high-incident energy behavior of the Bethe cross section. Selected experimental data are included.

  10. Shooting and bouncing rays - Calculating the RCS of an arbitrarily shaped cavity

    NASA Technical Reports Server (NTRS)

    Ling, Hao; Chou, Ri-Chee; Lee, Shung-Wu

    1989-01-01

    A ray-shooting approach is presented for calculating the interior radar cross section (RCS) from a partially open cavity. In the problem considered, a dense grid of rays is launched into the cavity through the opening. The rays bounce from the cavity walls based on the laws of geometrical optics and eventually exit the cavity via the aperture. The ray-bouncing method is based on tracking a large number of rays launched into the cavity through the opening and determining the geometrical optics field associated with each ray by taking into consideration (1) the geometrical divergence factor, (2) polarization, and (3) material loading of the cavity walls. A physical optics scheme is then applied to compute the backscattered field from the exit rays. This method is so simple in concept that there is virtually no restriction on the shape or material loading of the cavity. Numerical results obtained by this method are compared with those for the modal analysis for a circular cylinder terminated by a PEC plate. RCS results for an S-bend circular cylinder generated on the Cray X-MP supercomputer show significant RCS reduction. Some of the limitations and possible extensions of this technique are discussed.

  11. NEUTRON ACTIVATION CROSS SECTIONS AT 25 Kev

    Microsoft Academic Search

    Rex Booth; William Ball; Malcolm MacGregor

    1958-01-01

    Neutron activation cross sections have been measured at 25 kev for 31 ; isotopes. An Sb-Be photoneutron source was used, and thermal activations served ; to calibrate the beta- and gamma-detector efficiencies. The cross sections were ; measnred relative to iodine. A comparison was made between measured cross ; sections and predictions based on known low-energy resonance parameters. (auth);

  12. Actinide cross section program at ORELA

    Microsoft Academic Search

    Dabbs; J. W. T

    1980-01-01

    The actinide cross section program at ORELA, the Oak Ridge Electron Linear Accelerator, is aimed at obtaining accurate neutron cross sections (primarily fission, capture, and total) for actinide nuclides which occur in fission reactors. Such cross sections, measured as a function of neutron energy over as wide a range of energies as feasible, comprise a data base that permits calculated

  13. Neutron Activation Cross Sections at 25 kev

    Microsoft Academic Search

    Rex Booth; William P. Ball; Malcolm H. MacGregor

    1958-01-01

    Neutron activation cross sections have been measured at 25 kev for 31 isotopes. An Sb-Be photoneutron source was used, and thermal activations served to calibrate the beta- and gamma-detector efficiencies. The cross sections were measured relative to iodine. A comparison was made between measured cross sections and predictions based on known low-energy resonance parameters.

  14. UNCLASSIFIED CROSS SECTIONS FOR FAST REACTOR CALCULATIONS

    Microsoft Academic Search

    Bjorklund

    1953-01-01

    ABS>A compilation of estimated capture and total cross sections is given ; for 47 elements. Transport and inelastic cross sections are tabulated for ; various elements and curves of these cross sections vs. pertinent nuclear ; properties are given. (C.J.G.);

  15. Detecting and mitigating wind turbine clutter for airspace radar systems.

    PubMed

    Wang, Wen-Qin

    2013-01-01

    It is well recognized that a wind turbine has a large radar cross-section (RCS) and, due to the movement of the blades, the wind turbine will generate a Doppler frequency shift. This scattering behavior may cause severe interferences on existing radar systems including static ground-based radars and spaceborne or airborne radars. To resolve this problem, efficient techniques or algorithms should be developed to mitigate the effects of wind farms on radars. Herein, one transponder-based mitigation technique is presented. The transponder is not a new concept, which has been proposed for calibrating high-resolution imaging radars. It modulates the radar signal in a manner that the retransmitted signals can be separated from the scene echoes. As wind farms often occupy only a small area, mitigation processing in the whole radar operation will be redundant and cost inefficient. Hence, this paper uses a transponder to determine whether the radar is impacted by the wind farms. If so, the effects of wind farms are then mitigated with subsequent Kalman filtering or plot target extraction algorithms. Taking airborne synthetic aperture radar (SAR) and pulse Doppler radar as the examples, this paper provides the corresponding system configuration and processing algorithms. The effectiveness of the mitigation technique is validated by numerical simulation results. PMID:24385880

  16. Ku-Band rendezvous radar performance computer simulation model

    NASA Technical Reports Server (NTRS)

    Magnusson, H. G.; Goff, M. F.

    1984-01-01

    All work performed on the Ku-band rendezvous radar performance computer simulation model program since the release of the preliminary final report is summarized. Developments on the program fall into three distinct categories: (1) modifications to the existing Ku-band radar tracking performance computer model; (2) the addition of a highly accurate, nonrealtime search and acquisition performance computer model to the total software package developed on this program; and (3) development of radar cross section (RCS) computation models for three additional satellites. All changes in the tracking model involved improvements in the automatic gain control (AGC) and the radar signal strength (RSS) computer models. Although the search and acquisition computer models were developed under the auspices of the Hughes Aircraft Company Ku-Band Integrated Radar and Communications Subsystem program office, they have been supplied to NASA as part of the Ku-band radar performance comuter model package. Their purpose is to predict Ku-band acquisition performance for specific satellite targets on specific missions. The RCS models were developed for three satellites: the Long Duration Exposure Facility (LDEF) spacecraft, the Solar Maximum Mission (SMM) spacecraft, and the Space Telescopes.

  17. [Fast neutron cross section measurements

    SciTech Connect

    Knoll, G.F.

    1992-10-26

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its data production'' phase.

  18. Annular-Cross-Section CFE Chamber

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

  19. Theoretical antideuteron-nucleus absorptive cross sections

    NASA Technical Reports Server (NTRS)

    Buck, W. W.; Norbury, J. W.; Townsend, L. W.; Wilson, J. W.

    1993-01-01

    Antideuteron-nucleus absorptive cross sections for intermediate to high energies are calculated using an ion-ion optical model. Good agreement with experiment (within 15 percent) is obtained in this same model for (bar p)-nucleus cross sections at laboratory energies up to 15 GeV. We describe a technique for estimating antinucleus-nucleus cross sections from NN data and suggest that further cosmic ray studies to search for antideuterons and other antinuclei be undertaken.

  20. A 240 GHZ POLARIMETRIC COMPACT RANGE FOR SCALE MODEL RCS MEASUREMENTS

    E-print Network

    Massachusetts at Lowell, University of

    A 240 GHZ POLARIMETRIC COMPACT RANGE FOR SCALE MODEL RCS MEASUREMENTS Guy B. DeMartinis, Michael J radar range operating at 240 GHz has been developed for obtaining Ku-band RCS measurements on 1:16th and rotating circular dihedral are used for polarimetric as well as RCS calibration. Cross-pol rejection ratios

  1. The Primitive Streak, Cross Section

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2011-06-23

    This FlashTM animation is the third of a seven part series that presents the primitive streak from different angles. This installment displays the cross section, which is conducive to observing invagination. Epiblast cells ingress through the middle of the germ disc, to differentiate into either endoderm or mesenchymal mesoderm. The endoderm proliferates to drive the hypoblast into the extraembryonic endoderm of the yolk sac. The mesenchyme spreads between the epiblast and endoderm. Although not drawn to scale, the progressive thickening from lateral to paraxial mesoderm is depicted. To open the animation using Internet Explorer follow these steps. (1.) Click the link for the animation. (2.) A dialog box may pop up that begins with the statement "Windows cannot open this file:" If this box does not appear proceed to step four. If it does choose "Select the program from a list," then click OK. (3.) Another dialog box will pop up that lists different programs. Make sure "Internet Explorer" is selected, then click OK. (4.) Internet Explorer will pop up. Beneath the toolbars at the top of the window a yellow bar will appear that reads "To help protect your security, Internet Explorer has restricted this webpage from running scripts or Active X controls that could access your computer. Click here for options..." Pass the cursor over this yellow bar and click the right mouse button. (5.) A dialog box will pop up. Left click the option "Allow Blocked Content." (6.) Another dialog box will appear labeled "Security Warning" asking you to confirm that you want to run the content. Click "Yes." (7.) The Flash animation will appear in the Internet Explorer Window. (8.) Instructions for navigating the lesson are provided by the first frame of the animation.

  2. High-frequency techniques for RCS prediction of plate geometries

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.

    1992-01-01

    The principal-plane scattering from perfectly conducting and coated strips and rectangular plates is examined. Previous reports have detailed Geometrical Theory of Diffraction/Uniform Theory of Diffraction (GTD/UTD) solutions for these geometries. The GTD/UTD solution for the perfectly conducting plate yields monostatic radar cross section (RCS) results that are nearly identical to measurements and results obtained using the Moment Method (MM) and the Extended Physical Theory of Diffraction (EPTD). This was demonstrated in previous reports. The previous analysis is extended to bistatic cases. GTD/UTD results for the principal-plane scattering from a perfectly conducting, infinite strip are compared to MM and EPTD data. A comprehensive overview of the advantages and disadvantages of the GTD/UTD and of the EPTD and a detailed analysis of the results from both methods are provided. Several previous reports also presented preliminary discussions and results for a GTD/UTD model of the RCS of a coated, rectangular plate. Several approximations for accounting for the finite coating thickness, plane-wave incidence, and far-field observation were discussed. Here, these approximations are replaced by a revised wedge diffraction coefficient that implicitly accounts for a coating on a perfect conductor, plane-wave incidence, and far-field observation. This coefficient is computationally more efficient than the previous diffraction coefficient because the number of Maliuzhinets functions that must be calculated using numerical integration is reduced by a factor of 2. The derivation and the revised coefficient are presented in detail for the hard polarization case. Computations and experimental data are also included. The soft polarization case is currently under investigation.

  3. Atlas of Photoneutron Cross Sections Obtained with Monoenergetic Photons

    Microsoft Academic Search

    S. S. Dietrich; B. L. Berman

    1988-01-01

    Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of

  4. Nuclear Cross Sections For Fast Reactors

    Microsoft Academic Search

    S. Yiftah; M. Sieger

    1964-01-01

    The 16-group YOM cross section set for fast reactor analysis has been widely used by fast reactor centers during the last three years. Since its publication at the end of 1960, a considerable amount of experimental results as well as some theoretical investigations have become available. Also, various 'users' have kindly sent queries and remarks on the different cross sections

  5. Radiation pressure cross section for fluffy aggregates

    Microsoft Academic Search

    Hiroshi Kimura; Ingrid Mann

    1998-01-01

    —We apply the discrete dipole approximation (DDA) to estimate the radiation pressure cross section for fluffy aggregates by computing the asymmetry parameter and the cross sections for extinction and scattering. The ballistic particle–cluster aggregate and the ballistic cluster–cluster aggregate consisting of either dielectric or absorbing material are considered to represent naturally existing aggregates. We show that the asymmetry parameter perpendicular

  6. Surface interpolation from sparse cross-sections

    E-print Network

    Drummond, Tom

    Surface interpolation from sparse cross-sections using region correspondence G.M. Treece, R complex. In this paper, an algorithm is presented which can interpolate a surface through sparse, complex cross-sections. This is an extension of maximal disc guided interpolation [25], which is itself based

  7. Direct reaction effects on compound cross sections

    Microsoft Academic Search

    P. A. Moldauer

    1975-01-01

    Two effects of a direct reaction on compound processes are discussed: the enhancement of the average compound cross section that competes with the direct process and the cross correlations in the fluctuations of cross sections involving the directly coupled channels. For the case of two directly coupled channels it is shown that both effects are maximized at the causality limit

  8. Direct reaction effects on compound cross sections

    Microsoft Academic Search

    P. Moldauer

    1975-01-01

    Two effects of a direct reaction on compound processes are discussed: ; the enhancement of the average compound cross section that competes with the ; direct process and the cross correlations in the fluctuations of cross sections ; involving the directly coupled channels. For the case of two directly coupled ; channels it is shown that both effects are maximized

  9. Temperature dependence of unshielded cross-sections in multigroup cross-section sets

    Microsoft Academic Search

    V. Gopalakrishnan

    2000-01-01

    The self-shielding factor method in the multigroup approach is well known in Reactor Physics. The temperature and background dependent neutron cross-sections are conventionally represented in a problem-independent multigroup cross-section set by specifying for each group and reaction the unshielded cross-section (at 0 K) along with a set of self-shielding factors for various background cross-sections and temperatures. Usually the unshielded group

  10. Backscatter RCS for TE and TM excitations of dielectric-filled cavity-backed apertures in two-dimensional bodies

    NASA Technical Reports Server (NTRS)

    Goggans, Paul M.; Shumpert, Thomas H.

    1991-01-01

    Transverse electric (TE) and transverse magnetic (TM) scattering from dielectric-filled, cavity-backed apertures in two-dimensional bodies are treated using the method of moments technique to solve a set of combined-field integral equations for the equivalent induced electric and magnetic currents on the exterior of the scattering body and on the associated aperture. Results are presented for the backscatter radar cross section (RCS) versus the electrical size of the scatterer for two different dielectric-filled cavity-backed geometries. The first geometry is a circular cylinder of infinite length which has an infinite length slot aperture along one side. The cavity inside the cylinder is dielectric filled and is also of circular cross section. The two cylinders (external and internal) are of different radii and their respective longitudinal axes are parallel but not collocated. The second is a square cylinder of infinite length which has an infinite length slot aperture along one side. The cavity inside the square cylinder is dielectric-filled and is also of square cross section.

  11. High-frequency techniques for RCS prediction of plate geometries

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.

    1991-01-01

    Radar cross section (RCS) prediction of several rectangular plate geometries is discussed using high-frequency techniques such as the Uniform Theory of Diffraction (UTD) for perfectly conducting and impedance wedges and the Method of Equivalent Currents (MEC). Previous reports have presented detailed solutions to the principal-plane scattering by a perfectly conducting and a coated rectangular plate and nonprincipal-plane scattering by a perfectly conducting plate. These solutions are briefly reviewed and a modified model is presented for the coated plate. Theoretical and experimental data are presented for the perfectly conducting geometries. Agreement between theory and experiment is very good near and at normal incidence. In regions near and at grazing incidence, the disagreement between the data vary according to diffraction distances and angles involved. It is these areas of disagreement which are of extreme interest as an explanation for the disagreement will yield invaluable insight into scattering mechanisms which are not yet identified as major contributors near and at grazing incidence. Areas of disagreement between theory and experiment are identified and examined in an attempt to better understand and predict near-grazing incidence, grazing incidence, and nonprincipal-plane diffractions.

  12. Calculated medium-energy fission cross sections

    SciTech Connect

    Arthur, E.D.; Young, P.G.

    1988-01-01

    Calculations were made of neutron-induced fission cross sections on /sup 238/U and /sup 237/Np to compare with new data available up to 100 MeV. This process also produced fission barrier parameters for neptunium and uranium compound systems required for calculation of p + /sup 238/U fission cross sections. To achieve reasonable agreement with higher energy neutron-induced fission data, a phenomenological enhancement to barrier heights based upon the average angular momentum of the compound system was required. These calculational procedures resulted in predictions of /sup 238/U(p,f) cross sections that agree well with available data. 7 refs., 2 figs.

  13. RCS of a coated circular waveguide terminated by a perfect conductor

    NASA Technical Reports Server (NTRS)

    Lee, Choon S.; Lee, Shung-Wu

    1987-01-01

    The radar cross section (RCS) of a circular waveguide terminated by a perfect electric conductor is calculated by the geometrical theory of diffraction for the rim diffraction and by a physical optics approximation for the interior irradiation. The interior irradiation is generally more than 10 dB higher than the rim diffraction for a/lambda equal to or greater than 1 (a is the waveguide radius, lambda is the free-space wavelength). At low frequencies (a/lambda about 1), the interior irradiation can be significantly reduced over a broad range of incident angle if the interior waveguide wall is coated with a thin layer (1 percent of the radius) of lossy magnetic material. Our theoretical prediction is confirmed by measurements. At higher frequencies (a/lambda about 3), a thin layer of coating is effective for the case of near axial incidence, provided that a good transition of the TE(11) mode near the waveguide opening to the HE(11) mode inside the waveguide is made. A thicker layer of coating is required for the RCS reduction over wider incident angle.

  14. RCS computation of airplane using parabolic equation

    Microsoft Academic Search

    A. R. Mallahzadeh; M. Soleimani; J. Rashed-Mohassel

    2005-01-01

    The parabolic equation method gives accurate results in calculation of scattering from objects with dimensions ranging from one to tens of wavelengths. Solving parabolic equation with the marching method needs limited computer storage even for scattering calculations of large targets. In this paper, first the calculation procedure of radar cross section using parabolic equation in three dimensions is studied and

  15. Verification of the Rayleigh scattering cross section

    Microsoft Academic Search

    Sayan Chakraborti

    2007-01-01

    A simple experiment is described for the direct determination of the wavelength dependence of the Rayleigh scattering cross section using the classic example of the blue sky. Suggestions for inclusion into an undergraduate lab are discussed.

  16. Fragmentation Cross Sections in Heavy Ion Collisions

    NASA Astrophysics Data System (ADS)

    Bian, Bao-An; Zhang, Feng-Shou; Zhou, Hong-Yu

    The fragment cross sections are calculated for reactions of Ne collisions with C, Al, Cu, Sn, Ta, and Pb targets at 600 Mev/nucleon using the the isospin-dependent Boltzmann-Langevin equation. We found that the production cross sections for fragments Z = 2 to 9 are qualitatively reproduced by the present calculations except for C target. In order to understand the effects of heavy ion interaction with biomolecules well, we calculate the fragmentation cross sections for reactions of 12C + 2H, 12C, 14N, 16O at beam energies from 50 to 100 MeV/nucleon. It is found that fragment species increase approximately with increasing target mass. The obvious increment of the fragment cross sections for heavier targets at the beam energies from 50 to 80 MeV/nucleon are shown.

  17. International Evaluation of Neutron Cross Section Standards

    NASA Astrophysics Data System (ADS)

    Carlson, A. D.; Pronyaev, V. G.; Smith, D. L.; Larson, N. M.; Chen, Zhenpeng; Hale, G. M.; Hambsch, F.-J.; Gai, E. V.; Oh, Soo-Youl; Badikov, S. A.; Kawano, T.; Hofmann, H. M.; Vonach, H.; Tagesen, S.

    2009-12-01

    Neutron cross section standards are the basis for the determination of most neutron cross sections. They are used for both measurements and evaluations of neutron cross sections. Not many cross sections can be obtained absolutely - most cross sections are measured relative to the cross section standards and converted using evaluations of the standards. The previous complete evaluation of the neutron cross section standards was finished in 1987 and disseminated as the NEANDC/INDC and ENDF/B-VI standards. R-matrix model fits for the light elements and non-model least-squares fits for all the cross sections in the evaluation were the basis of the combined fits for all of the data. Some important reactions and constants are not standards, but they assist greatly in the determination of the standard cross sections and reduce their uncertainties - these data were also included in the combined fits. The largest experimental database used in the evaluation was prepared by Poenitz and included about 400 sets of experimental data with covariance matrices of uncertainties that account for all cross-energy, cross-reaction and cross-material correlations. For the evaluation GMA, a least-squares code developed by Poenitz, was used to fit all types of cross sections (absolute and shape), their ratios, spectrum-averaged cross sections and thermal constants in one full analysis. But, the uncertainties derived in this manner, and especially those obtained in the R-matrix model fits, have been judged to be too low and unrealistic. These uncertainties were substantially increased prior to their release in the recommended data files of 1987. Modified percentage uncertainties were reassigned by the United States Cross Section Evaluation Working Group's Standards Subcommittee for a wide range of energies, and no covariance (or correlation) matrices were supplied at that time. The need to re-evaluate the cross section standards is based on the appearance of a significant amount of precise experimental data and improved developments in the methodology of analysis and evaluation. Initial efforts to produce a new evaluation were made by the United States Cross Section Evaluation Working Group which formed a Task Force. It was realized that international cooperation would be needed to produce the evaluation. The Working Party on International Evaluation Cooperation of the Nuclear Energy Agency Nuclear Science Committee formed a Subgroup, and the International Atomic Energy Agency formed a Coordinated Research Project (CRP). These groups worked cooperatively to improve the evaluation process. The major effort in producing the evaluation was through the CRP. The evaluations of the neutron cross section standards were finalized in October 2005. Previous difficulties experienced with a data evaluation problem known as "Peelle's Pertinent Puzzle" create biases in the fit of correlated data, and they have been addressed to reduce this phenomenon. The new evaluations of the cross section standards also include covariance matrices of the uncertainties that contain fully justifiable values. The product of this international effort has been adopted as the neutron standards for ENDF/B-VII.0.

  18. Bibliography of photoabsorption cross-section data

    NASA Technical Reports Server (NTRS)

    Hudson, R. D.; Kieffer, L. J.

    1970-01-01

    This bibliography contains only references which report a measured or calculated photoabsorption cross section (relative or normalized) in regions of continuous absorption. The bibliography is current as of January 1, 1970.

  19. Asymptotic cross sections for composite projectile reactions 

    E-print Network

    Neves, Andrea Marolt Pimenta

    1995-01-01

    The First Born Approximation has been used to compute excitation and ionization cross sections for ion-atom collisions involving two electrons at high energies. The projectile is treated semi-classically following a straight line path and the target...

  20. MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.

    SciTech Connect

    ROCHMAN, D.; HERMAN, M.; OBLOZINSKY, P.

    2005-05-01

    This is the final report of the work performed under the LANL contract on the modeling and fission cross section for americium isotopes (May 2004-June 2005). The purpose of the contract was to provide fission cross sections for americium isotopes with the nuclear reaction model code EMPIRE 2.19. The following work was performed: (1) Fission calculations capability suitable for americium was implemented to the EMPIRE-2.19 code. (2) Calculations of neutron-induced fission cross sections for {sup 239}Am to {sup 244g}Am were performed with EMPIRE-2.19 for energies up to 20 MeV. For the neutron-induced reaction of {sup 240}Am, fission cross sections were predicted and uncertainties were assessed. (3) Set of fission barrier heights for each americium isotopes was chosen so that the new calculations fit the experimental data and follow the systematics found in the literature.

  1. Fragmentation Cross Sections in Heavy Ion Collisions

    Microsoft Academic Search

    Bao-An Bian; Feng-Shou Zhang; Hong-Yu Zhou

    2008-01-01

    The fragment cross sections are calculated for reactions of Ne collisions with C, Al, Cu, Sn, Ta, and Pb targets at 600 Mev\\/nucleon using the the isospin-dependent Boltzmann-Langevin equation. We found that the production cross sections for fragments Z = 2 to 9 are qualitatively reproduced by the present calculations except for C target. In order to understand the effects

  2. Path forward for dosimetry cross sections

    SciTech Connect

    Griffin, P.J. [Sandia National Laboratories, Albuquerque, NM 87185-1146 (United States); Peters, C.D. [Sandia Staffing Alliance, Albuquerque, NM 87110 (United States)

    2011-07-01

    In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of experimental data in the evaluation. (authors)

  3. Evaluation methods for neutron cross section standards

    SciTech Connect

    Bhat, M.R.

    1980-01-01

    Methods used to evaluate the neutron cross section standards are reviewed and their relative merits, assessed. These include phase-shift analysis, R-matrix fit, and a number of other methods by Poenitz, Bhat, Kon'shin and the Bayesian or generalized least-squares procedures. The problems involved in adopting these methods for future cross section standards evaluations are considered, and the prospects for their use, discussed. 115 references, 5 figures, 3 tables.

  4. Rising Total Hadron-Hadron Cross Sections

    E-print Network

    Giorgio Giacomelli

    2007-12-06

    A historical summary is made on the measurements concerning the rising total hadron-hadron cross sections at high energies. The first part of this paper concerns the total cross section measurements performed at the Brookhaven, Serpukhov and Fermilab fixed target accelerators; then the measurements at the CERN Intersecting Storage Rings (ISR), and at the CERN and at the Tevatron Fermilab proton-antiproton colliders; finally the cosmic ray measurements at even higher energies. A short discussion on Conclusions and Perspectives follows.

  5. Predicting the Total Charm Cross Section

    SciTech Connect

    Vogt, R

    2008-05-29

    We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. Extracting the total charm cross section from data is a non-trivial task. To go from a finite number of measured D mesons in a particular decay channel to the total c{bar c} cross section one must: divide by the branching ratio for that channel; correct for the luminosity, {sigma}{sub D} = N{sub D}/Lt; extrapolate to full phase space from the finite detector acceptance; divide by two to get the pair cross section from the single Ds; and multiply by a correction factor to account for unmeasured charm hadrons. Early fixed-target data were at rather low p{sub T}, making the charm quark mass the most relevant scale. At proton and ion colliders, although the RHIC experiments can access the full pT range and thus the total cross section, the data reach rather high p{sub T}, p{sub T} >> m, making p{sub T} (m{sub T}) the most relevant scale. Here we focus on the total cross section calculation where the quark mass is the only relevant scale.

  6. Shuttle rendezvous radar performance: evaluation and simulation

    Microsoft Academic Search

    J. W. Griffin; A. C. Lindberg; T. B. Ahn; P. L. Harton

    1989-01-01

    The authors describe the performance evaluation and simulation of the Ku-band shuttle rendezvous radar. Computer simulation, using the radar cross section for specific spacecraft, provided an estimate of rendezvous radar range performance for that spacecraft. The radar cross section model included smooth metallic surfaces, rough surfaces, and shadowing effects, as well as phase differences due to different path lengths to

  7. Actinide cross section program at ORELA

    SciTech Connect

    Dabbs, J.W.T.

    1980-01-01

    The actinide cross section program at ORELA, the Oak Ridge Electron Linear Accelerator, is aimed at obtaining accurate neutron cross sections (primarily fission, capture, and total) for actinide nuclides which occur in fission reactors. Such cross sections, measured as a function of neutron energy over as wide a range of energies as feasible, comprise a data base that permits calculated predictions of the formation and removal of these nuclides in reactors. The present program is funded by the Division of Basic Energy Sciences of DOE, and has components in several divisions at ORNL. For intensively ..cap alpha..-active nuclides, many of the existing fission cross section data have been provided by underground explosions. New measurement techniques, developed at ORELA, now permit linac measurements on fissionable nuclides with alpha half-lives as short as 28 years. Capture and capture-plus-fission measurements utilize scintillation detectors (of capture ..gamma.. rays and fission neutrons) in which pulse shape discrimination plays an important role. Total cross sections can be measured at ORELA on samples of only a few milligrams. A simultaneous program of chemical and isotopic analyses of samples irradiated in EBR-II is in progress to provide benchmarks for the existing differential measurements. These analyses are being studied with updated versions of ORIGEN and with sensitivity determinations. Calculations of the sensitivity to cross section changes of various aspects of the nuclear fuel cycle are also being made. Even in this relatively mature field, many cross sections still require improvements to provide an adequate data base. Examples of recent techniques and measurements are presented. 12 figures, 3 tables.

  8. Lidar Bacscatter Cross-Section Radar Bacscatter Cross-Section Mixed Phase

    E-print Network

    Eloranta, Edwin W.

    of Okhotsk Lake Lake Great Bear Great Slave Sea Baltic Black Sea Sea Bering Strait Chukchi average minimum Great Bear Great Slave Sea Baltic Black Sea Sea Bering Strait Chukchi average minimum extent of sea ice

  9. SSC 50 mm dipole cross section

    SciTech Connect

    Gupta, R.C.; Kahn, S.A.; Morgan, G.H.

    1991-01-01

    In this paper we present the magnetic design of the two dimensional coil and iron cross section, referred to as DSX201/W6733, for the 50 mm aperture main ring dipole magnet for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of random errors on the coil placement and the Lorentz forces on the coil will be presented. The yoke has been optimized to reduce iron saturation effects on the field harmonics. We shall present the summary of this design which will include the expected overall performance of this cross section. Prototypes of these dipoles are being built at the Brookhaven National Laboratory (BNL) and at the Fermi National Accelerator Laboratory (FNAL). There are slight differences between the cross sections at the two laboratories. 7 refs., 6 figs., 11 tabs.

  10. Top differential cross section measurements (Tevatron)

    SciTech Connect

    Jung, Andreas W.

    2012-01-01

    Differential cross sections in the top quark sector measured at the Fermilab Tevatron collider are presented. CDF used 2.7 fb{sup -1} of data and measured the differential cross section as a function of the invariant mass of the t{bar t} system. The measurement shows good agreement with the standard model and furthermore is used to derive limits on the ratio {kappa}/M{sub Pl} for gravitons which decay to top quarks in the Randall-Sundrum model. D0 used 1.0 fb{sup -1} of data to measure the differential cross section as a function of the transverse momentum of the top-quark. The measurement shows a good agreement to the next-to-leading order perturbative QCD prediction and various other standard model predictions.

  11. Revised cross section for RHIC dipole magnets

    SciTech Connect

    Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.

    1991-01-01

    Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.

  12. Electroweak Cross-sections and Widths

    SciTech Connect

    Robson, Aidan; /Glasgow U.

    2008-10-01

    The status of W and Z cross-section and width measurements from the CDF and D0 experiments is reviewed. Recent results that are discussed: the cross-section for Z production times the branching ratio to tau pairs, the rapidity and transverse momentum distributions of Z production in the electron channel, and the direct measurements of the W width and the Z invisible width; the latter from an analysis of events with large missing transverse energy and one or more energetic jets.

  13. Covariance Evaluation Methodology for Neutron Cross Sections

    SciTech Connect

    Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.

    2008-09-01

    We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.

  14. Modeling the interactions between the ocean and the environment for microwave radar sensing

    NASA Technical Reports Server (NTRS)

    Weissman, David E.

    1987-01-01

    An extensive set of X-band microwave backscatter measurements has been analyzed to determine its dependence on winds near the surface, atmospheric stability, and long-wave slopes. These radar measurements, made from a tower in the Gulf of Mexico, were performed in conjunction with an extensive set of simultaneous environmental measurements. The CW microwave system operated at an incidence angle of 45 deg, with antennas directed into winds and waves. Model functions for the radar cross section (RCS) and the modulation transfer function (MTF) are developed that depend on the geophysical variables, including wind stress. Statistical analysis shows that these models functions yield a significant smaller error when fit to the RCS data than a simple wind-speed function displays. A Taylor-series expansion of the returned power from a small area provides a unified function that demonstrates the complementary roles of wave slope and atmospheric fluctuations on both the RCS, the MTF, and the coherence. The issue of linearity of the MTF is addressed with this data set, yielding evidence that this is a valid assumption. These results have direct application to the remote sensing of the mean and fluctuating winds, and the wave spectrum with coherent and incoherent active radars.

  15. Neutron scattering lengths and cross sections

    Microsoft Academic Search

    Varley F. Sears

    1992-01-01

    The application of thermal neutron scattering to the study of the structure and dynamics of condensed matter requires a knowledge of the scattering lengths and the corresponding scattering and absorption cross sections of the elements. Ln some cases, values for the individual isotopes are needed as well. This information is required to obtain an absolute normalization ofthe scatteredneutron distributions, tocalculate

  16. UV absorption cross sections for SO3

    Microsoft Academic Search

    James B. Burkholder; Stuart McKeen

    1997-01-01

    Room temperature gas phase absorption cross sections for SO3 have been measured over the wavelength range 195 to 330 nm using a diode array spectrometer. The SO3 spectrum is continuous with weak diffuse vibrational band structure in the 225 to 295 nm region. Atmospheric photolysis rate calculations show that photolysis of SO3 in the 190 to 230 nm actinic window

  17. The RAT SCAT cross-section facility

    Microsoft Academic Search

    H. C. Marlow; D. C. Watson; C. H. Van Hoozer; C. C. Freeny

    1965-01-01

    A description of the RAT SCAT cross-section facility is reported along with test results indicating measurement capabilities. The facility is described in terms of location, type of range, type of measurements, and the equipment complement. Measurement capabilities are presented in terms of vehicle dimensions and weight, relative to criteria such as system background, vehicle support background, nonplanar fields, and instrumentation

  18. Absolute photoionization cross sections of atomic oxygen

    NASA Astrophysics Data System (ADS)

    Berkowitz, J.

    1997-02-01

    Conflicting calibrations of the absolute photoionization cross sections of atomic oxygen in the vacuum and extreme ultraviolet are tested by a sum-rule analysis. It is shown that the scaling factor obtained by Samson and Pareek results in much closer adherence to three sum rules.

  19. ZIRCONIUM CROSS SECTIONS FOR REACTOR CALCULATIONS

    Microsoft Academic Search

    W. Skolnik; N. C. Francis

    1959-01-01

    It is shown that the use of realistic Zr cross sections in the ; calculations of the group constants, yields values or k\\/sub eff\\/ in substantial ; agreement with the Goldsmith predictions and experiments. A companison of ages ; of Zr-Hâ0 mixtures was made between calculated and experimental results. A ; number of clean critical experiments were calcillated in a

  20. A Pebble Bed Reactor cross section methodology

    Microsoft Academic Search

    Nathanael H. Hudson; Abderrafi. M. Ougouag; Farzad Rahnema; Hans Gougar

    2009-01-01

    A method is presented for the evaluation of microscopic cross sections for the Pebble Bed Reactor (PBR) neutron diffusion computational models during convergence to an equilibrium (asymptotic) fuel cycle. This method considers the isotopics within a core spectral zone and the leakages from such a zone as they arise during reactor operation. The randomness of the spatial distribution of fuel

  1. Radiation pressure cross section for fluffy aggregates.

    NASA Astrophysics Data System (ADS)

    Kimura, H.; Mann, I.

    1998-09-01

    The authors apply the discrete dipole approximation (DDA) to estimate the radiation pressure cross section for fluffy aggregates by computing the asymmetry parameter and the cross sections for extinction and scattering. The ballistic particle-cluster aggregate and the ballistic cluster-cluster aggregate consisting of either dielectric or absorbing material are considered to represent naturally existing aggregates. The authors show that the asymmetry parameter perpendicular to the direction of wave propagation is maximized where the wavelength is comparable to the aggregate size, which may be characterized by the area-equivalent radius or the radius of gyration rather than the volume-equivalent radius. The asymmetry parameter for the aggregate depends on the morphology of the particle, but not on the constituent material. Therefore, the dependence of the radiation pressure cross section on the material composition arises mainly from that of the extinction and scattering cross sections, in other words, the single-scattering albedo. The authors find that aggregates consisting of high-albedo material show a large deviation of radiation pressure from the direction of incident radiation. When the aggregates are illuminated by blackbody radiation, the deviation of the radiation pressure increases with increasing temperature of the blackbody.

  2. Cross Sections From Scalar Field Theory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank; Norman, Ryan B.; Nasto, Rachel

    2008-01-01

    A one pion exchange scalar model is used to calculate differential and total cross sections for pion production through nucleon- nucleon collisions. The collisions involve intermediate delta particle production and decay to nucleons and a pion. The model provides the basic theoretical framework for scalar field theory and can be applied to particle production processes where the effects of spin can be neglected.

  3. LSP-Nucleus Elastic Scattering Cross Sections

    E-print Network

    J. D. Vergados; T. S. Kosmas

    1997-01-02

    We calculate LSP-nucleus elastic scattering cross sections using some representative input in the restricted SUSY parameter space. The coherent matrix elements are computed throughout the periodic table while the spin matrix elements for the proposed $^{207}Pb$ target which has a rather simple nuclear structure. The results are compared to those given from other cold dark matter detection targets.

  4. Calculating Cross Sections of Composite Interstellar Grains

    E-print Network

    Nikolai V. Voshchinnikov; John S. Mathis

    1999-08-21

    Interstellar grains may be composite collections of particles of distinct materials, including voids, agglomerated together. We determine the various optical cross sections of such composite grains, given the optical properties of each constituent, using an approximate model of the composite grain. We assume it consists of many concentric spherical layers of the various materials, each with a specified volume fraction. In such a case the usual Mie theory can be generalized and the extinction, scattering, and other cross sections determined exactly. We find that the ordering of the materials in the layering makes some difference to the derived cross sections, but averaging over the various permutations of the order of the materials provides rapid convergence as the number of shells (each of which is filled by all of the materials proportionately to their volume fractions) is increased. Three shells, each with one layer of a particular constituent material, give a very satisfactory estimate of the average cross section produced by larger numbers of shells. We give the formulae for the Rayleigh limit (small size parameter) for multi-layered spheres and use it to propose an ``Effective Medium Theory'' (EMT), in which an average optical constant is taken to represent the ensemble of materials. Multi-layered models are used to compare the accuracies of several EMTs already in the literature.

  5. Calculating Cross Sections of Composite Interstellar Grains

    Microsoft Academic Search

    Nikolai V. Voshchinnikov; John S. Mathis

    1999-01-01

    Interstellar grains may be composite collections of particles of distinct materials, including voids agglomerated together. We determine the various optical cross sections of such composite grains, given the optical properties of each constituent, using an approximate model of the composite grain. We assume it consists of many concentric spherical layers of the various materials, each with a specified volume fraction.

  6. Stratigraphic Cross Section of Northeast Texas

    NSDL National Science Digital Library

    Minor Keith

    Cretaceous sedimentary rocks of Northeast Texas provide important clues about paleogeography, paleotectonics, and sea level fluctuation. This website describes several of these rock units and the geologic information they supply. An unpublished report with a thorough discussion, map, cross section, and numerous references is provided. Specific topics include Cretaceous stratigraphy, lithostratigraphic and biostratigraphic correlation, ammonites, Western Interior Seaway, Skull Creek Seaway, paleogeography, and paleotectonics.

  7. KLOE results on hadronic cross section

    NASA Astrophysics Data System (ADS)

    Mandaglio, Giuseppe; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Balwierz, I.; Bencivenni, G.; Bini, C.; Bloise, C; . Bocchetta, S.; Bossi, F.; Branchini, P.; Capon, G.; Capussela, T.; Ceradini, F.; Ciambrone, P.; Czerwi?ski, E.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, B.; Dreucci, M.; Felici, G.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Jacewicz, M.; Kluge, W.; Lee-Franzini, J.; Lukin, P.; Martemianov, M.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Morello, G.; Moulson, M.; Müller, S; . Napolitano, M.; Nguyen, F.; Palutan, M.; Passeri, A.; Patera, V.; Prado Longhi, I.; Santangelo, P.; Sciascia, B.; Silarski, M.; Spadaro, T.; Taccini, C.; Tortora, L.; Venanzoni, G.; Versaci, R.; Xu, G.; Zdebik, J.; Babusci, D.; Badoni, D.; Bocci, V.; Budano, A.; Bulychjev, S. A; .; Caldeira Balkeståhl, L.; Campana, P.; Dané, E.; De Robertis, G.; Domenici, D.; Erriquez, O.; Fanizzi, G.; Giardina, G.; Gonnella, F.; Happacher, F.; Höistad, B.; Iafolla, L.; Iarocci, E.; Johansson, T.; Kowalewska, A.; Kulikov, V.; Kupsc, A.; Loddo, F.; Mandaglio, G.; Mascolo, M.; Matsyuk, M.; Messi, R.; Moricciani, D.; Ranieri, A.; Redmer, C. F.; Sarra, I.; Schioppa, M.; Sciubba, A.; Wi?licki, W.; Wolke, M.; KLOE/KLOE-2 Collaborations

    2012-03-01

    The KLOE experiment at the phi - factory DA?NE is the first to have exploited Initial State Radiation (ISR) to precisely determine the e+e- ? ?+?-(?) cross section below 1 GeV, representing the 70% of the leading order contribution to the muon anomaly. The leading order contribution ahlo? is presently the main source of uncertainty in the theoretical evaluation of the muon anomaly, and it can be evaluated by dispersion integral using the experimental measurement of hadronic cross section. A persistent discrepancy of about 3 ? between standard model (SM) prediction and experimental measurements of the muon anomalous magnetic moment has been up to now observed. The KLOE collaboration published two measurements of the ?+?- cross section with the photon in the initial state emitted at small polar angle in Phys. Lett. B vol. 606 pg. 12 and vol. 670 pg. 285, and an independent measurement with the photon emitted at large polar angle in Phys. Lett. B vol. 700 pg. 102. These measurements were normalized to the DA?NE luminosity. Recently, a new analysis deriving the pion form factor directly from measuring the bin-by-bin ?+?? and ?+?? final states ratio has been performed. In this paper, the preliminary results of this new measurement and the comparison to the previous published ones, the impact on the evaluation of the hadronic contribution to the muon anomaly, the preliminary ?+?? cross section measurement and the comparison with the PHOKHARA-MC prediction are presented.

  8. Neutron cross section standards and flux determinations above thermal energies

    Microsoft Academic Search

    1975-01-01

    The recent worldwide advances in nuclear technology, particularly fast fission and fusion reactors, have revealed the need for accurate neutron reaction cross sections for the design of these systems. The accuracies of these cross sections are generally limited by the standard cross sections relative to which they are measured. With the exception of the hydrogen scattering cross section, there have

  9. Absolute np and pp cross section determinations aimed at improving the standard for cross section measurements

    SciTech Connect

    Laptev, Alexander B [Los Alamos National Laboratory; Haight, Robert C [Los Alamos National Laboratory; Tovesson, Fredrik [Los Alamos National Laboratory; Arndt, Richard A [GWU; Briscoe, William J [GWU; Paris, Mark W [GWU; Strakovsky, Igor I [GWU; Workman, Ron L [GWU

    2010-01-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses (PW As) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-V11.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  10. Absolute np and pp Cross Section Determinations Aimed At Improving The Standard For Cross Section Measurements

    SciTech Connect

    Laptev, A. B.; Haight, R. C.; Tovesson, F. [Los Alamos National Laboratory, Los Alamos NM 87545 (United States); Arndt, R. A.; Briscoe, W. J.; Paris, M. W.; Strakovsky, I. I.; Workman, R. L. [George Washington University, Washington DC 20052 (United States)

    2011-06-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1 GeV are determined based on partial-wave analyses (PWAs) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-VII.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  11. Averaging cross section data so we can fit it

    SciTech Connect

    Brown, D.

    2014-10-23

    The 56Fe cross section we are interested in have a lot of fluctuations. We would like to fit the average of the cross section with cross sections calculated within EMPIRE. EMPIRE is a Hauser-Feshbach theory based nuclear reaction code, requires cross sections to be smoothed using a Lorentzian profile. The plan is to fit EMPIRE to these cross sections in the fast region (say above 500 keV).

  12. Electron capture cross sections for stellar nucleosynthesis

    E-print Network

    P. G. Giannaka; T. S. Kosmas

    2015-02-25

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  13. Electron capture cross sections for stellar nucleosynthesis

    E-print Network

    Giannaka, P G

    2015-01-01

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  14. The calculation of rainbow scattering cross sections

    Microsoft Academic Search

    R. J. Munn; Francis J. Smith

    1966-01-01

    A method is described for calculating low resolution differential cross sections near the rainbow angle. It is used to calculate a table of the positions of the principal maxima and minima in the rainbow structure for a 6–12 potential for different rainbow angles and different values of the de Boer parameter, ?*, between 0·1 and 0·01. A comparison with similar

  15. Inclusive jet cross section measurement at CDF

    SciTech Connect

    Pagliarone, C. [Universita di Torino and INFN, Trieste (Italy)

    1996-08-01

    The CDF Collaboration has measured the inclusive jet cross section using 1992-93 collider data at 1.8 TeV. The CDF measurement is in very good agreement with NLO QCD predictions for transverse energies (E{sub T}) below 200 GeV. However, it is systematically higher than NLO QCD predictions for E{sub T} above 200 GeV.

  16. Electron excitation cross sections for Si XII

    Microsoft Academic Search

    S. Kastner; C. Wade; T. S. Smith; M. Blaha

    1972-01-01

    Excitation cross sections are calculated for Si XII by the coulomb-Born method, using numerical Hartree-Fock radial functions. The transitions considered are 2s-np, ns-n'd, 2p-nd and 3s-np. Reasonable agreement with the general results of Bely and Petrini is obtained, but an appreciable difference occurs for 2s-7p. The effect of including higher multipoles in the coulomb-Born method is illustrated. For comparison, the

  17. Neutron Activation Cross Section of Technetium98

    Microsoft Academic Search

    Edward Anders

    1958-01-01

    The cross section for the reaction Tc98(n, gamma)Tc99m was determined by thermal neutron irradiation of a cyclotron-produced sample containing Tc95, Tc97m, Tc97g, Tc98, and Tc99. The degree of selectivity and background reduction required to permit an accurate measurement of the Tc98 content, 2.68+\\/-0.54 disintegrations per minute, was attained by means of beta-(740-Kev gamma) coincidence counting. At a thermal flux of

  18. How to Calculate Colourful Cross Sections Efficiently

    SciTech Connect

    Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank

    2008-09-03

    Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.

  19. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1982-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  20. Radar cross section reduction by lumped, linear, passive loading

    SciTech Connect

    Bevensee, R.M.

    1985-10-01

    A general analysis describing total power scattered from lossy, electrically linear bodies of arbitrary shape, excited by single-frequency plane waves, is modified to treat bistatic scattered power, p/sub sc/, in a specified solid angle. Formulas are given for the passive load at a selected port to minimize p/sub sc/ in terms of four real radiation field parameters and the input impedance. The analysis is illustrated for a thin-wire aircraft model, lambda/2 long. p/sub sc/ in a 60 cone is first minimized for nose-on incidence of a circularly-polarized wave, and then reduced for many incident waves by lumped loading at two ports. An iterative scheme was employed to converge on the loads. Even the simple loading scheme employed reduced p/sub sc/ by at least 12.8 dB for each of the 56 directions of incidence within the 60 scatter cone.

  1. NIST XCOM: Photon Cross Sections Database

    NSDL National Science Digital Library

    This web program, funded in part by the National Institute of Standards and Technology (U.S.) is used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, in any element, compound or mixture, at energies from 1 keV to 100 GeV. The contents section of the site contains an introduction, database for elements, interpolation and combination, instructions on how to run the XCOM program, and references. The site allows you to download a copy of XCOM (v. 3.1) for personal use.

  2. Neutron activation cross sections on lead isotopes

    Microsoft Academic Search

    V. Semkova; P. Reimer; T. Altzitzoglou; A. J. M. Plompen; C. Quetel; S. Sudar; J. Vogl; A. J. Koning; S. M. Qaim; D. L. Smith

    2009-01-01

    The cross sections for the reactions ²°Pb(n,n{sup '})²°Pb{sup m}, ²°Pb(n,2n)²°³Pb, ²°Pb(n,2n)²°³Pb{sup m1}, ²°Pb(n,3n)²°²Pb{sup m}, ²°Pb(n,3n)²°Pb{sup m}, ²°Pb(n,)²°³Hg, and ²°Pb(n,p)²°Tl were determined at the IRMM van de Graaff laboratory in the neutron energy range from 14 to 21 MeV. Both natural and enriched samples were irradiated with neutrons produced via the ³H(d,n)He reaction. The induced activities were determined by gamma-ray spectrometry

  3. Dielectronic recombination cross sections of neonlike xenon

    NASA Astrophysics Data System (ADS)

    Dewitt, D. R.; Schneider, D.; Chen, M. H.; Clark, M. W.; McDonald, J. W.; Schneider, M. B.

    1992-03-01

    High-resolution measurements of dielectronic recombination cross sections for neonlike xenon (Xe44+) are presented. The experimental method consists of the formation and interaction of ions with electrons in an ion trap followed by an analysis of the extracted ions to determine relative yields. Low beam currents are used to obtain an energy resolution of 16 eV FWHM. Reductions in the number of initial ions of more than 3 orders of magnitude are observed as the strongest resonances are scanned. The relative contributions of the LMM, LMN, LMO, LMP, and LMQ groups of resonances are compared to theoretical calculations. The agreement with theory is excellent.

  4. Top Production Cross Sections at D0

    SciTech Connect

    Kvita, Jiri

    2009-07-01

    We report on measurements of the ttbar production cross section at a center-of-mass energy of 1.96 TeV at the D0 experiment during Run II of the Fermilab Tevatron collider. We use candidate events in lepton+jets and dilepton final states. In the most sensitive channel (lepton+jets channel), a neural network algorithm that uses lifetime information to identify b-quark jets is used to distinguish signal from background processes. We also present measurements of single top quark production at D0 using several multivariate techniques to separate signal from background.

  5. Statistics of cross sections of Voronoi tessellations

    NASA Astrophysics Data System (ADS)

    Ferraro, M.; Zaninetti, L.

    2011-10-01

    In this paper, we investigate relationships between the volumes of cells of three-dimensional Voronoi tessellations and the lengths and areas of sections obtained by intersecting the tessellation with a randomly oriented plane. Here, in order to obtain analytical results, Voronoi cells are approximated to spheres. First, the probability density function for the lengths of the radii of the sections is derived and it is shown that it is related to the Meijer G function; its properties are discussed and comparisons are made with the numerical results. Next, the probability density function for the areas of cross sections is computed and compared with the results of numerical simulations.

  6. Fig. 1: Cross-section of experimental combustor and instrumentation

    E-print Network

    Hallett, William L.H.

    Fig. 1: Cross-section of experimental combustor and instrumentation Fig. 2: Cross-section of tip and analysis. The reactor diameter was 23 cm and the bed height was maintained at 22 cm for these tests. More

  7. EXPLAINING DISCREPANCIES BETWEEN LONGITUDINAL AND CROSS-SECTIONAL MODELS

    EPA Science Inventory

    Discrepancies between estimates obtained from longitudinal studies analyzed cross-sectionally and longitudinally pose questions about the validity of cross-sectional estimates of change. n some cases these discrepancies are the result of period effects, cohort effects, or selecti...

  8. Fast Neutron Activation Cross Section of Au197

    Microsoft Academic Search

    S. A. Cox

    1961-01-01

    The neutron activation cross section of gold was measured in the neutron range from 30-1500 kev. The absolute value of the cross section was based on the U235 fast fission cross section which was used for absolute neutron flux measurements from 200-1500 kev. For measurements below 200 kev, the B10(n, alpha) cross section was used for monitoring the neutron flux.

  9. Electron Elastic-Scattering Cross-Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 64 NIST Electron Elastic-Scattering Cross-Section Database (PC database, no charge)   This database provides values of differential elastic-scattering cross sections, corresponding total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron energies between 50 eV and 20,000 eV (in steps of 1 eV).

  10. Analytic Cross Sections for Substructure Lensing

    E-print Network

    Charles R. Keeton

    2002-10-28

    The magnifications of the images in a strong gravitational lens system are sensitive to small mass clumps in the lens potential; this effect has been used to infer the amount of substructure in galaxy dark matter halos. I study the theory of substructure lensing to identify important general features, and to compute analytic cross sections that will facilitate further theoretical studies. I show that the problem of a clump anywhere along the line of sight to a lens can be mapped onto an equivalent problem of a clump in a simple convergence and shear field; clumps at arbitrary redshifts are therefore not hard to handle in calculations. For clumps modeled as singular isothermal spheres (SIS), I derive simple analytic estimates of the cross section for magnification perturbations of a given strength. The results yield two interesting conceptual points. First, lensed images with positive parity are always made brighter by SIS clumps; images with negative parity can be brightened but are much more likely to be dimmed. Second, the clumps need not lie within the lens galaxy; they can be moved in redshift by several tenths and still have a significant lensing effect. Isolated small halos are expected to be common in hierarchical structure formation models, but it is not yet known whether they are abundant enough compared with clumps inside lens galaxies to affect the interpretation of substructure lensing.

  11. Neutronic Cross Section Calculations on Fluorine Nucleus

    NASA Astrophysics Data System (ADS)

    Kara, A.; Tel, E.

    2013-06-01

    Certain light nuclei such as Lithium (Li), Beryllium (Be), Fluorine (F) (which are known as FL?BE) and its molten salt compounds (LiF, BeF2 and NaF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure. These molten salt compounds are also a good neutron moderator. In this study, cross sections of neutron induced reactions have been calculated for fluorine target nucleus. The new calculations on the excitation functions of 19F( n, 2n), 19F( n, p), 19F( n, xn), 19F( n, xp) have been made. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, the ( n, 2n) and ( n, p) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The multiple pre-equilibrium mean free path constant from internal transition have been investigated for 19F nucleus. The obtained results have been discussed and compared with the available experimental data.

  12. Mental Visualization of Objects from Cross-Sectional Images

    ERIC Educational Resources Information Center

    Wu, Bing; Klatzky, Roberta L.; Stetten, George D.

    2012-01-01

    We extended the classic anorthoscopic viewing procedure to test a model of visualization of 3D structures from 2D cross-sections. Four experiments were conducted to examine key processes described in the model, localizing cross-sections within a common frame of reference and spatiotemporal integration of cross sections into a hierarchical object…

  13. Making a Geologic Cross Section Name _____________________________ Geology 100 Harbor Section

    E-print Network

    Harbor, David

    of cross section A for help) 2. What symbols represent these formations and in what geologic time periodsp. 1 Making a Geologic Cross Section Name _____________________________ Geology 100 ­ Harbor Section Your task is to complete a cross section of geologic structures from a geologic map. Please do

  14. ANALYTIC EXPRESSIONS FOR AEROSOL LIGHT-SCATTERING CROSS SECTION

    E-print Network

    ANALYTIC EXPRESSIONS FOR AEROSOL LIGHT-SCATTERING CROSS SECTION Ernie R. Lewis For Presentation Upton, NY 11973-5000 www.bnl.gov ABSTRACT The light-scattering cross section is an intrinsic property consisting of spherical particles of uniform composition, the light-scattering cross section can

  15. Neutron standard cross sections in reactor physics - Need and status

    Microsoft Academic Search

    1990-01-01

    The design and improvement of nuclear reactors require detailed neutronics calculations. These calculations depend on comprehensive libraries of evaluated nuclear cross sections. Most of the cross sections that form the data base for these evaluations have been measured relative to neutron cross-section standards. The use of these standards can often simplify the measurement process by eliminating the need for a

  16. Effects of charge exchange cross section on ENAs

    Microsoft Academic Search

    K. Scherer; H. Fichtner

    2006-01-01

    A crucial point in interpreting the data of the upcoming IBEX mission is a good knowledge of the charge exchange cross section between shocked solar wind protons and interstellar hydrogen There exists at least four formulae which describe the data for the respective cross section We will discuss the effects of the different cross sections for the ENA flux at

  17. Measurement of the lidar cross sections of cube corner arrays for laser ranging of satellites

    NASA Technical Reports Server (NTRS)

    Minott, P. O.

    1974-01-01

    The satellite coordinate system necessary to describe the location and orientation of each cube corner in the array is discussed. The method of optical testing is described along with the gain function, and computational methods for deriving the gain function and experimental values for it. The velocity aberration is derived as a function of satellite orbit, a complete method for cross section evaluation is described, and finally the radar equation is described.

  18. Graphs of the cross sections in the Alternate Monte Carlo Cross Section library at the Los Alamos Scientific Laboratory

    SciTech Connect

    Seamon, R.E.; Soran, P.D.

    1980-06-01

    Graphs of all neutron cross sections and photon production cross sections on the Alternate Monte Carlo Cross Section (AMCCS) library have been plotted along with local neutron heating numbers. The values of ..nu..-bar, the average number of neutrons per fission, are also plotted for appropriate isotopes.

  19. Graphs of the cross sections in the recommended Monte Carlo cross-section library at the Los Alamos Scientific Laboratory

    SciTech Connect

    Soran, P.D.; Seamon, R.E.

    1980-05-01

    Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ..nu.., the average number of neutrons per fission, are also given.

  20. Radar

    Microsoft Academic Search

    James R. Zimbelman; Kenneth S. Edgett

    1994-01-01

    Over 1,000,000 km2 of the equatorial surface of Mars west of the Arsia Mons volcano displays no 3.5-cm radar echo to the very low level of the radar system noise for the Very Large Array; the area displaying this unique property has been terms \\

  1. Collision cross sections for structural proteomics.

    PubMed

    Marklund, Erik G; Degiacomi, Matteo T; Robinson, Carol V; Baldwin, Andrew J; Benesch, Justin L P

    2015-04-01

    Ion mobility mass spectrometry (IM-MS) allows the structural interrogation of biomolecules by reporting their collision cross sections (CCSs). The major bottleneck for exploiting IM-MS in structural proteomics lies in the lack of speed at which structures and models can be related to experimental data. Here we present IMPACT (Ion Mobility Projection Approximation Calculation Tool), which overcomes these twin challenges, providing accurate CCSs up to 10(6) times faster than alternative methods. This allows us to assess the CCS space presented by the entire structural proteome, interrogate ensembles of protein conformers, and monitor molecular dynamics trajectories. Our data demonstrate that the CCS is a highly informative parameter and that IM-MS is of considerable practical value to structural biologists. PMID:25800554

  2. Neutron activation cross sections on lead isotopes

    Microsoft Academic Search

    V. Semkova; P. Reimer; T. Altzitzoglou; A. J. M. Plompen; C. Quétel; S. Sudár; J. Vogl; A. J. Koning; S. M. Qaim; D. L. Smith

    2009-01-01

    The cross sections for the reactions Pb204(n,n'gamma)Pb204m, Pb204(n,2n)Pb203, Pb204(n,2n)Pb203m1, Pb204(n,3n)Pb202m, Pb206(n,3n)Pb204m, Pb206(n,alpha)Hg203, and Pb208(n,p)Tl208 were determined at the IRMM van de Graaff laboratory in the neutron energy range from 14 to 21 MeV. Both natural and enriched samples were irradiated with neutrons produced via the H3(d,n)He4 reaction. The induced activities were determined by gamma-ray spectrometry using a HPGe detector in

  3. Neutron activation cross sections for zirconium isotopes

    Microsoft Academic Search

    V. Semkova; E. Bauge; A. J. M. Plompen; D. L. Smith

    2010-01-01

    New experimental cross sections are presented for Zr90(n,?)87mSr, Zr90(n,x)89mY, Zr90(n,p)90mY, Zr90(n,2n)89Zr, Zr90(n,2n)89mZr, Zr91(n,n?)87mSr, Zr91(n,x)90mY, Zr91(n,p)91mY, Zr92(n,x)91mY, Zr92(n,p)92Y, Zr94(n,?)91Sr, Zr94(n,x)93Y and Zr94(n,p)94Y reactions. These have been obtained with the activation technique using gamma-ray spectrometry and irradiations at the IRMM Van de Graaff laboratory. The new data were obtained in the energy range from 14 to 21 MeV. In nearly all cases

  4. Dielectronic recombination cross sections of neonlike xenon

    SciTech Connect

    DeWitt, D.R.; Schneider, D.; Chen, M.H.; Clark, M.W.; McDonald, J.W.; Schneider, M.B. (Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States))

    1992-03-16

    High-resolution measurements of dielectronic recombination cross sections for neonlike xenon (Xe{sup 44+}) are presented. The experimental method consists of the formation and interaction of ions with electrons in an ion trap followed by an analysis of the extracted ions to determine relative yields. Low beam currents are used to obtain an energy resolution of 16 eV FWHM. Reductions in the number of initial ions of more than 3 orders of magnitude are observed as the strongest resonances are scanned. The relative contributions of the {ital LMM}, {ital LMN}, {ital LMO}, {ital LMP}, and {ital LMQ} groups of resonances are compared to theoretical calculations. The agreement with theory is excellent.

  5. Angle-averaged Compton cross sections

    SciTech Connect

    Nickel, G.H.

    1983-01-01

    The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

  6. Correlation cross sections along the international border

    SciTech Connect

    Martiniuk, C.D. (Manitoba Energy and Mines, Winnipeg (Canada)); Le Fever, J.A.; Anderson, S.B. (North Dakota Geological Survey, Grand Forks (United States))

    1991-06-01

    The Manitoba-North Dakota (Canada-US) stratigraphic correlation project is a joint study between the Petroleum Branch of Manitoba Energy and Mines and the North Dakota Geological Survey. It is an attempt to correlate the differing stratigraphic terminologies established in the two jurisdictions by providing a reference cross section across the international boundary. The study involves the subsurface correlation of logs of the Paleozoic and Mesozoic sequences in the Manitoba and North Dakota portions of the Williston basin. The Paleozoic and Mesozoic sequences are subdivided for presentation into the following stratigraphic intervals: (a) Cambrian-Ordovician-Silurian, (b) Devonian, (c) Mississippian, (d) Jurassic, and (e) Cretaceous. Wireline logs show the actual stratigraphic correlations. A nomenclature chart is also presented from each sequence. In addition, the sections include a generalized description of lithologies, thicknesses, environments of deposition, and petroleum potential for each geographic area.

  7. Status of high energy neutron cross sections

    SciTech Connect

    Browne, J.C.; Lisowski, P.W.

    1980-01-01

    Review is presented of the current status of neutron-induced reactions of interest to the fusion community in the 10- to 50-MeV neutron energy range. Although there has been significant activity in this area since the 1977 BNL Symposium on Neutron Cross Sections from 10 to 40 MeV, this review concludes that there are many areas which require more experimentation to obtain the requested accuracy. Examples of various neutron data obtained since 1977 are presented and compared to determine the extent of agreement. An attempt is made to determine what the prospects are for satisfying the fusion data needs defined by the US DOE based upon progress to date.

  8. Diffractive DIS Cross Sections and Parton Distributions

    E-print Network

    F. -P. Schilling

    2006-08-31

    Highlights are presented mainly from two recent measurements of the diffractive Deep Inelastic Scattering cross section at HERA. In the first, the process $ep\\to eXp$ is studied by tagging the leading final state proton. In the second, events of this type are selected by requiring a large rapidity gap devoid of hadronic activity in the proton direction. The two measurements are compared in detail and the kinematic dependences are interpreted within the framework of a factorisable diffractive exchange. Diffractive parton distributions are determined from a next-to-leading order QCD analysis of the large rapidity gap data, which can be applied to the prediction of diffractive processes, also at the TEVATRON and the LHC.

  9. SUBMITTED TO THE IEEE TRANSACTIONS ON SIGNAL PROCESSING 1 Evaluation of Transmit Diversity in

    E-print Network

    Haimovich, Alexander

    signals at the array elements. In conventional radar, the target's radar cross section (RCS) fluctuations is that it provides measures to overcome those degradations or even utilizes the RCS fluctuations for new applications by its radar cross section (RCS) function [6]. A target's RCS represents the amount of energy reflected

  10. Facile synthesis, phase transition, optical switching and oxidation resistance properties of belt-like VO{sub 2}(A) and VO{sub 2}(M) with a rectangular cross section

    SciTech Connect

    Zhang, Yifu; Huang, Yanfen; Zhang, Juecheng; Wu, Weibing; Niu, Fei; Zhong, Yalan [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)] [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu, Xinghai, E-mail: liuxh@whu.edu.cn [School of Printing and Packaging, Wuhan University, Wuhan 430079 (China)] [School of Printing and Packaging, Wuhan University, Wuhan 430079 (China); Liu, Xin [School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)] [School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Huang, Chi, E-mail: chihuang@whu.edu.cn [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)] [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2012-08-15

    Highlights: ? Belt-like VO{sub 2}(A) with a rectangular cross section was synthesized. ? The formation mechanism of belt-like VO{sub 2}(A) was proposed. ? Belt-like VO{sub 2}(M) was prepared by the irreversible transformation of VO{sub 2}(A). ? VO{sub 2}(A) and VO{sub 2}(M) can be used as the optical switching materials. ? VO{sub 2}(A) and VO{sub 2}(M) have good oxidation resistance below 400 °C in air. -- Abstract: Belt-like VO{sub 2}(A) with a rectangular cross section (VA-RCS) was successfully synthesized using V{sub 2}O{sub 5}, H{sub 2}C{sub 2}O{sub 4}·2H{sub 2}O and H{sub 2}O as the starting materials by a facile hydrothermal approach. Some synthetic parameters, such as, the reaction time, reaction temperature and concentration of H{sub 2}C{sub 2}O{sub 4}·2H{sub 2}O, were systematically investigated to control the fabrication of belt-like VA-RCS. The formation mechanism of belt-like VA-RCS was proposed. Subsequently, belt-like VO{sub 2}(M) with a rectangular cross section (VM-RCS) was prepared by the irreversible transformation of VA-RCS at 700 °C for 2 h under the inert atmosphere. The phase transition temperature (T{sub c}) of VA-RCS and VM-RCS was evaluated by DSC test. The optical switching properties of VA-RCS and VM-RCS were studied by the variable-temperature infrared spectra, and it was found that the as-obtained VA-RCS and VM-RCS could be used as the optical switching materials. Furthermore, the oxidation resistance properties of VA-RCS and VM-RCS were investigated by TGA, indicating that they have good thermal stability and oxidation resistance below 400 °C in air.

  11. Free Antineutrino Absorption Cross Section. I. Measurement of the Free Antineutrino Absorption Cross Section by Protons

    Microsoft Academic Search

    Frederick Reines; Clyde L. Cowan

    1959-01-01

    The cross section for the reaction p(nu¯, beta+)n was measured using antineutrinos (nu¯) from a powerful fission reactor at the Savannah River Plant of the United States Atomic Energy Commission. Target protons were provided by a 1.4×103 liter liquid scintillation detector in which the scintillator solution (triethylbenzene, terphyenyl, and POPOP) was loaded with a cadmium compound (cadmium octoate) to allow

  12. Abdominal sarcoidosis: cross-sectional imaging findings

    PubMed Central

    Gezer, Naciye Sinem; Ba?ara, I??l; Altay, Canan; Harman, Mustafa; Rocher, Laurence; Karabulut, Nevzat; Seçil, Mustafa

    2015-01-01

    Sarcoidosis is a multisystem inflammatory disease of unknown etiology. The lungs and the lymphoid system are the most commonly involved organs. Extrapulmonary involvement is reported in 30% of patients, and the abdomen is the most common extrapulmonary site with a frequency of 50%–70%. Although intra-abdominal sarcoidosis is usually asymptomatic, its presence may affect the prognosis and treatment options. The lesions are less characteristic and may mimick neoplastic or infectious diseases such as lymphoma, diffuse metastasis, and granulomatous inflammation. The liver and spleen are the most common abdominal sites of involvement. Sarcoidosis of the gastrointestinal system, pancreas, and kidneys are extremely rare. Adenopathy which is most commonly found in the porta hepatis, exudative ascites, and multiple granulomatous nodules studding the peritoneum are the reported manifestations of abdominal sarcoidosis. Since abdominal sarcoidosis is less common and long-standing, unrecognized disease can result in significant morbidity and mortality. Imaging contributes to diagnosis and management of intra-abdominal sarcoidosis. In this report we reviewed the cross-sectional imaging findings of hepatobiliary, gastrointestinal, and genitourinary sarcoidosis. PMID:25512071

  13. [Fast neutron cross section measurements]. Progress report

    SciTech Connect

    Knoll, G.F.

    1992-10-26

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are ``clean`` and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its ``data production`` phase.

  14. Normalization of experimental electron cross sections.

    NASA Astrophysics Data System (ADS)

    Avdonina, N.; Felfli, Z.; Msezane, A. Z.

    1997-10-01

    Absolute experimental electron-impact differential cross sections (DCSs) can be obtained through an extrapolation of the relative generalized oscillator strength (GOS) values at some given impact energy E to zero momentum transfer squared K^2, the optical oscillator strength (OOS) [1]. We propose to normalize the relative experimental DCS data to the corresponding OOS value by extrapolating the GOS to K^2 = 0 without involving the nonphysical region. This is possible only by simultaneously increasing E and decreasing K^2 so that K^2 = 0 corresponds to E = ?. Thus is avoided a divergence of fracd(GOS)d(K^2) at K^2 = 0 [2]. Another advantage of our method is that, over a wide range of small K^2 values the contribution of higher order terms of the Born series to the GOS function is negligible, contrary to the constant E case in which even order K^2 terms are non-Born [2]. Thus first Born approximation can be used to normalize relative experimental DCSs to the OOS. This method is applicable to both the excitation and ionization of atomic and molecular targets by electron impact. The latter case generalizes the method of ref. [3]. ^*Supported by AFOSR, NSF and DoE Div. of Chemical Sciences, OBES. ^1 E. N. Lassettre et al., J. Chem. Phys \\underline50, (1829) ^2 W. M. Huo, J. Chem. Phys \\underline71, 1593 (1979) ^3 A. Saenz, W Weyrich and P. Froelich, J. Phys. B \\underline29, 97 (1996)

  15. Abdominal sarcoidosis: cross-sectional imaging findings.

    PubMed

    Gezer, Naciye Sinem; Ba?ara, I??l; Altay, Canan; Harman, Mustafa; Rocher, Laurence; Karabulut, Nevzat; Seçil, Mustafa

    2015-01-01

    Sarcoidosis is a multisystem inflammatory disease of unknown etiology. The lungs and the lymphoid system are the most commonly involved organs. Extrapulmonary involvement is reported in 30% of patients, and the abdomen is the most common extrapulmonary site with a frequency of 50%-70%. Although intra-abdominal sarcoidosis is usually asymptomatic, its presence may affect the prognosis and treatment options. The lesions are less characteristic and may mimick neoplastic or infectious diseases such as lymphoma, diffuse metastasis, and granulomatous inflammation. The liver and spleen are the most common abdominal sites of involvement. Sarcoidosis of the gastrointestinal system, pancreas, and kidneys are extremely rare. Adenopathy which is most commonly found in the porta hepatis, exudative ascites, and multiple granulomatous nodules studding the peritoneum are the reported manifestations of abdominal sarcoidosis. Since abdominal sarcoidosis is less common and long-standing, unrecognized disease can result in significant morbidity and mortality. Imaging contributes to diagnosis and management of intra-abdominal sarcoidosis. In this report we reviewed the cross-sectional imaging findings of hepatobiliary, gastrointestinal, and genitourinary sarcoidosis. PMID:25512071

  16. Cross sections for actinide burner reactors

    SciTech Connect

    Difilippo, F.C.

    1991-01-01

    Recent studies have shown the feasibility of burning higher actinides (i.e., transuranium (TRU) elements excluding plutonium) in ad hoc designed reactors (Actinide Burner Reactors: ABR) which, because of their hard neutron spectra, enhance the fission of TRU. The transmutation of long-lived radionuclides into stable or short-lived isotopes reduces considerably the burden of handling high-level waste from either LWR or Fast Breeder Reactors (FBR) fuels. Because of the large concentrations of higher actinides in these novel reactor designs the Doppler effect due to TRU materials is the most important temperature coefficient from the point of view of reactor safety. Here we report calculations of energy group-averaged capture and fission cross sections as function of temperature and dilution for higher actinides in the resolved and unresolved resonance regions. The calculations were done with the codes SAMMY in the resolved region and URR in the unresolved regions and compared with an independent calculation. 4 refs., 2 figs., 2 tabs.

  17. Electron ionization cross sections for the PH3 molecule

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev

    2014-08-01

    The partial single, double differential cross-sections with their total (sum of partial cross sections) of the phosphine (PH3) by direct and dissociative electron ionization have been evaluated by using modified Jain-Khare semi-empirical approach. To the best of my knowledge, no other data (experimental and/or theoretical) of differential cross sections is available till now for comparison. Partial and total integral ionization cross sections were also evaluated for PH3. Integral ionization cross-sections show good agreement with available experimental/or theoretical data. Ionization rate coefficients corresponding to partial ionization cross-sections have also been calculated by the Maxwell-Boltzmann distribution of energy.

  18. Determining the Uncertainty on the Total Heavy Flavor Cross Section

    SciTech Connect

    Vogt, R

    2008-07-22

    We assess the theoretical uncertainties on the total heavy quark cross section. We discuss the importance of the quark mass, the scale choice, the number of light flavors and the parton densities on the estimate of the uncertainty. At first glance, the uncertainty bands on the total charm cross sections obtained by integrating the FONLL inclusive cross section and by integrating the partonic total cross sections appear to be incompatible. We explain how this apparent difference arises and describe how the two results can be reconciled. The small charm quark mass amplifies the effect of varying the other parameters in the calculation, making the uncertainty on the total charm cross section difficult to quantify. On the other hand, the bottom quark total cross section is under much better theoretical control and differences between the two approaches are small.

  19. Color dipole cross section and inelastic structure function

    E-print Network

    Yu Seon Jeong; C. S. Kim; Minh Vu Luu; Mary Hall Reno

    2014-08-20

    Instead of starting from a theoretically motivated form of the color dipole cross section in the dipole picture of deep inelastic scattering, we start with a parametrization of the deep inelastic structure function for electromagnetic scattering with protons, and then extract the color dipole cross section. Using the parametrizations of $F_2(\\xi=x \\ {\\rm or}\\ W^2,Q^2)$ by Donnachie-Landshoff and Block et al., we find the dipole cross section from an approximate form of the presumed dipole cross section convoluted with the perturbative photon wave function for virtual photon splitting into a color dipole with massless quarks. The color dipole cross section determined this way reproduces the original structure function within about 10\\% for $0.1$ GeV$^2\\leq Q^2\\leq 10$ GeV$^2$. We discuss the large and small form of the dipole cross section and compare with other parameterizations.

  20. Calculation of beam neutralization in the IPNS-Upgrade RCS

    SciTech Connect

    Chae, Yong-Chul

    1995-01-26

    The author calculated the neutralization of circulating beam in this report. In the calculation it is assumed that all electrons liberated from the background molecules due to the collisional processes are trapped in the potential well of the proton beam. Including the dependence of ionization cross sections on the kinetic energy of the incident particle, the author derived the empirical formula for beam neutralization as a function of time and baseline vacuum pressure, which is applicable to the one acceleration cycle of the IPNS-Upgrade RCS.

  1. High E{sub T} jet cross sections at CDF

    SciTech Connect

    Flaugher, B.; CDF Collaboration

    1996-08-01

    The inclusive jet cross section for {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV as measured by the CDF collaboration will be presented. Preliminary CDF measurements of the {Sigma} E{sub T} cross section at {radical}s = 1.8 TeV and the central inclusive jet cross section at {radical}s = 0.630 TeV will also be shown.

  2. Projectile and Lab Frame Differential Cross Sections for Electromagnetic Dissociation

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Adamczyk, Anne; Dick, Frank

    2008-01-01

    Differential cross sections for electromagnetic dissociation in nuclear collisions are calculated for the first time. In order to be useful for three - dimensional transport codes, these cross sections have been calculated in both the projectile and lab frames. The formulas for these cross sections are such that they can be immediately used in space radiation transport codes. Only a limited amount of data exists, but the comparison between theory and experiment is good.

  3. Drell-Yan Cross Section in the Jet Calculus Scheme

    E-print Network

    Hidekazu Tanaka; Hirokazu Kobayashi

    2009-05-02

    We calculate factorized cross sections for lepton pair production mediated by a virtual photon in hadron-hadron collisions using the jet calculus scheme, in which a kinematical constraint due to parton radiation is taken into account. This method guarantees a proper phase space boundary for subtraction terms. Some properties of the calculated cross sections are examined. We also discuss matching between the hard scattering cross sections and parton showers at the next-to-leading logarithmic (NLL) order of quantum chromodynamics (QCD).

  4. Thermal neutron capture cross sections of the palladium isotopes

    Microsoft Academic Search

    M. Krticka; R. B. Firestone; D. P. McNabb; B. Sleaford; U. Agvaanluvsan; T. Belgya; Z. S. Revay

    2008-01-01

    Precise thermal neutron capture gamma-ray cross sections sigmagamma were measured for all elements with Z=1-83,90, and 92, except for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the

  5. Thermal neutron capture cross sections of the palladium isotopes

    Microsoft Academic Search

    M. Krticka; R. B. Firestone; D. P. McNabb; B. Sleaford; U. Agvaanluvsan; T. Belgya; Z. S. Revay

    2008-01-01

    Precise thermal neutron capture -ray cross sections {sub } were measured for all elements with Z=1-83,90, and 92, for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the

  6. Total elastic cross sections for metastable argon on xenon

    Microsoft Academic Search

    A. Barrios; M. Faxas; J. Li

    1993-01-01

    Total scattering cross sections have been measured using single beam attenuation of a metastable argon atom mixed ³P{sub 2,0} beam scattered from xenon. After relative velocity and angular corrections are made, preliminary data give a total scattering cross section of 700 ± 65 â«Â² (at a relative velocity of 1000 m\\/s) is found. Earlier experiments give a total cross section

  7. Measured microwave scattering cross sections of three meteorite specimens

    NASA Technical Reports Server (NTRS)

    Hughes, W. E.

    1972-01-01

    Three meteorite specimens were used in a microwave scattering experiment to determine the scattering cross sections of stony meteorites and iron meteorites in the frequency range from 10 to 14 GHz. The results indicate that the stony meteorites have a microwave scattering cross section that is 30 to 50 percent of their projected optical cross section. Measurements of the iron meteorite scattering were inconclusive because of specimen surface irregularities.

  8. e+e- Hadron Production Cross Sections at Belle

    NASA Astrophysics Data System (ADS)

    Crnkovic, Jason D.

    2014-12-01

    A number of production cross sections for electron-positron annihilation to a hadronic final state have been measured using the Belle dataset, which is possible given the general purpose design of the Belle detector and its large solid-angle coverage. The cross section measurements predominantly fall above 3 GeV, which still leaves the opportunity for using the dataset to systematically measure cross sections below 3 GeV. These low-energy cross sections are important for improving the precision of the Standard Model prediction for the muon anomalous magnetic moment.

  9. DBCC Software as Database for Collisional Cross-Sections

    NASA Astrophysics Data System (ADS)

    Moroz, Daniel; Moroz, Paul

    2014-10-01

    Interactions of species, such as atoms, radicals, molecules, electrons, and photons, in plasmas used for materials processing could be very complex, and many of them could be described in terms of collisional cross-sections. Researchers involved in plasma simulations must select reasonable cross-sections for collisional processes for implementing them into their simulation codes to be able to correctly simulate plasmas. However, collisional cross-section data are difficult to obtain, and, for some collisional processes, the cross-sections are still not known. Data on collisional cross-sections can be obtained from numerous sources including numerical calculations, experiments, journal articles, conference proceedings, scientific reports, various universities' websites, national labs and centers specifically devoted to collecting data on cross-sections. The cross-sections data received from different sources could be partial, corresponding to limited energy ranges, or could even not be in agreement. The DBCC software package was designed to help researchers in collecting, comparing, and selecting cross-sections, some of which could be constructed from others or chosen as defaults. This is important as different researchers may place trust in different cross-sections or in different sources. We will discuss the details of DBCC and demonstrate how it works and why it is beneficial to researchers working on plasma simulations.

  10. On the excess in the inclusive cross section

    NASA Astrophysics Data System (ADS)

    Monni, Pier Francesco; Zanderighi, Giulia

    2015-05-01

    In this note we analyse the excess in the W + W - inclusive cross section recently measured at the LHC. We point out that in fact for the ATLAS fiducial cross sections there is no excess in the measurements compared to the NLO QCD predictions. We also argue that higher order effects to the fiducial cross section are small, and tend to cancel each other, hence the inclusion of NNLO and NNLL corrections will not modify this agreement significantly. We find that at 8 TeV a substantial part of the disagreement with the NLO prediction for the total cross section observed by ATLAS is due to the extrapolation carried out with POWHEG.

  11. Neutron-capture Cross Sections from Indirect Measurements

    SciTech Connect

    Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

    2011-10-18

    Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  12. Initial cross section for photodissociation of phosgene on Ag(111)

    NASA Astrophysics Data System (ADS)

    Zhou, X.-L.; White, J. M.

    1990-01-01

    The initial cross section for UV photodissociation of phosgene (Cl2CO) on Ag(111) at 100 K has been measured. With photon energies greater than 2.6 eV, submonolayer Cl2CO is readily photodissociated to surface Cl(a) and gas phase CO(g). The evolution of CO during photodissociation is readily monitored and used to calculate the initial photodissociation rate and cross section. The cross section is higher than the gas phase absorption cross section and is in the range of 10-18-10-19 cm2. It depends on the wavelength and the Cl2CO coverage.

  13. Analysis of the Radar Reflectivity of Aircraft Vortex Wakes

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Wray, Alan; Yan, Jerry (Technical Monitor)

    2000-01-01

    Radar has been proposed as a way to track wake vortices to reduce aircraft spacing and tests have revealed radar echoes from aircraft wakes in clear air. The results are always interpreted qualitatively using Tatarski's theory of weak scattering by isotropic atmospheric turbulence. The goal of the present work was to predict the value of the radar cross-section (RCS) using simpler models. This is accomplished in two steps. First, the refractive index is obtained. Since the structure of the aircraft wakes is different from atmospheric turbulence, three simple mechanisms specific to vortex wakes are considered: (1) Radial density gradient in a two-dimensional vortex, (2) three-dimensional fluctuations in the vortex cores, and (3) Adiabatic transport of the atmospheric fluid in a two-dimensional oval surrounding the pair of vortices. The index of refraction is obtained more precisely for the two-dimensional mechanisms than for the three-dimensional ones. In the second step, knowing the index of refraction, a scattering analysis is performed. Tatarski's weak scattering approximation is kept but the usual assumptions of a far-field and a uniform incident wave are dropped. Neither assumption is generally valid for a wake that is coherent across the radar beam. For analytical insight, a simpler approximation that invokes, in addition to weak scattering, the far-field and wide cylindrical beam assumptions, is also developed and compared with the more general analysis. The predicted RCS values for the oval surround the vortices (mechanism C) agree with the experiments of Bilson conducted over a wide range of frequencies. However, the predictions have a cut-off away from normal incidence which is not present in the measurements. Estimates suggest that this is due to turbulence in the baroclinic vorticity generated at the boundary of the oval. The reflectivity of a vortex itself (mechanism A) is comparable to that of the oval (mechanism C) but cuts-off at frequencies lower than those considered in all the experiments to date. The RCS of a vortex happens to peak at the frequency (about 49 MHz) where atmospheric radars (known as ST radars) operate and so the present prediction could be verified in the future. Finally , we suggest that hot engine exhaust could increase RCE by 40 db and reveal vortex circulation, provided its mixing with the surroundings is prevented in the laminarising flow of the vortices.

  14. Active radar stealth device

    Microsoft Academic Search

    R. N. Cain; Albert J. Corda

    1991-01-01

    This patent discloses an active radar stealth device mounted on a host platform for minimizing the radar cross-section of the host platform. A coating which is essentially microwave transparent is attached to the surface of a host platform and is exposed to an incident microwave field. A plurality of detector\\/emitter pairs contained within the coating detect and actively cancel, respectively,

  15. Hafnium neutron cross sections and resonance analysis

    NASA Astrophysics Data System (ADS)

    Trbovich, Michael J.

    The focus of this thesis is to determine resonance parameters for the stable hafnium isotopes in the 0.005--200 eV region, with emphasis on the overlapping 176Hf and 178Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it an ideal material for controlling nuclear reactions. Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) LINAC using the time of flight method. Transmission experiments utilized 6Li glass scintillation detectors at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen section NaI(Tl) multiplicity type detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotope-enriched liquid samples. The liquid samples were designed to provide information on the 176Hf and 178Hf contributions to the 8 eV doublet without saturation. Data analysis was done using the R-matrix Bayesian fitting code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for some of the multiple scattering effects in yield data. The resolution function for specific experimental setups was determined. A method was developed for estimating errors on the fitted resonance parameters due to uncertainties in the resolution function parameters. The combined capture and transmission data analysis yielded resonance parameters for all stable hafnium isotopes from 0.005--200 eV. Resonance integrals were calculated along with errors for each of the hafnium isotopes using the NJOY and INTER codes. The isotopic resonance integrals calculated were significantly different than some of the previous values; however the calculated elemental hafnium resonance integral changed very little.

  16. Polarization control in high power microwaves from a rectangular cross section gyrotron

    SciTech Connect

    Hochman, J.M.; Gilgenbach, R.M.; Jaynes, R.J.; Rintamaki, J.I.; Lau, Y.Y.; Spencer, T.A. [Univ. of Michigan, Ann Arbor, MI (United States)

    1997-12-31

    The authors summarize the results of experiments on a gyrotron utilizing rectangular-cross-section (RCS) interaction cavities. Current issues under investigation include polarization control as a function of magnetic field, power versus pulselength of microwave emission, and mode competition. The electron beam driver producing an annular beam is the Michigan Electron Long Beam Accelerator (MELBA). The annular e-beam is spun up into an axis-encircling beam by passing it through a magnetic cusp prior to entering the RCS interaction cavity. Initial experimental results show a high degree of polarization [P(TE{sub 10})/P(TE{sub 01}) = 30 or 1/30] as a function of cavity fields. Megawatt microwave output shifts from the fundamental mode, which dominates the next order mode by an order of magnitude, to the next order mode as the field is raised from 1.4 to 1.7 kGauss. Frequency measurements using microstrip bandpass filters and a superheterodyne mixer support this result as well as MAGIC simulations. MAGIC code simulations using various magnetic fields will be presented as well as results utilizing the E-gun code.

  17. Comparison between the activation cross sections and integrated cross sections for the radiative capture of 14 MeV neutrons

    Microsoft Academic Search

    F. Cvelbar; A. Hudoklin; M. Potokar

    1970-01-01

    Cross sections obtained by the integration of prompt gamma-ray spectra from the radiative capture of 14 MeV neutrons in a series of elements are presented and compared wilh the activation cross sections reported by different authors. In contrast to the activation cross-section values, which are scattered between 1 mb and 10 mb as a function of mass number, the integrated

  18. Cross Sections for Inner-Shell Ionization by Electron Impact

    SciTech Connect

    Llovet, Xavier, E-mail: xavier@ccit.ub.edu [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain)] [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Powell, Cedric J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States)] [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States); Salvat, Francesc [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain)] [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Jablonski, Aleksander [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)] [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2014-03-15

    An analysis is presented of measured and calculated cross sections for inner-shell ionization by electron impact. We describe the essentials of classical and semiclassical models and of quantum approximations for computing ionization cross sections. The emphasis is on the recent formulation of the distorted-wave Born approximation by Bote and Salvat [Phys. Rev. A 77, 042701 (2008)] that has been used to generate an extensive database of cross sections for the ionization of the K shell and the L and M subshells of all elements from hydrogen to einsteinium (Z = 1 to Z = 99) by electrons and positrons with kinetic energies up to 1 GeV. We describe a systematic method for evaluating cross sections for emission of x rays and Auger electrons based on atomic transition probabilities from the Evaluated Atomic Data Library of Perkins et al. [Lawrence Livermore National Laboratory, UCRL-ID-50400, 1991]. We made an extensive comparison of measured K-shell, L-subshell, and M-subshell ionization cross sections and of L? x-ray production cross sections with the corresponding calculated cross sections. We identified elements for which there were at least three (for K shells) or two (for L and M subshells) mutually consistent sets of cross-section measurements and for which the cross sections varied with energy as expected by theory. The overall average root-mean-square deviation between the measured and calculated cross sections was 10.9% and the overall average deviation was ?2.5%. This degree of agreement between measured and calculated ionization and x-ray production cross sections was considered to be very satisfactory given the difficulties of these measurements.

  19. Total cross sections for positrons scattered elastically from helium based on new measurements of total ionization cross sections

    NASA Technical Reports Server (NTRS)

    Diana, L. M.; Chaplin, R. L.; Brooks, D. L.; Adams, J. T.; Reyna, L. K.

    1990-01-01

    An improved technique is presented for employing the 2.3m spectrometer to measure total ionization cross sections, Q sub ion, for positrons incident on He. The new ionization cross section agree with the values reported earlier. Estimates are also presented of total elastic scattering cross section, Q sub el, obtained by subtracting from total scattering cross sections, Q sub tot, reported in the literature, the Q sub ion and Q sub Ps (total positronium formation cross sections) and total excitation cross sections, Q sub ex, published by another researcher. The Q sub ion and Q sub el measured with the 3m high resolution time-of-flight spectrometer for 54.9eV positrons are in accord with the results from the 2.3m spectrometer. The ionization cross sections are in fair agreement with theory tending for the most part to be higher, especially at 76.3 and 88.5eV. The elastic cross section agree quite well with theory to the vicinity of 50eV, but at 60eV and above the experimental elastic cross sections climb to and remain at about 0.30 pi a sub o sq while the theoretical values steadily decrease.

  20. 202 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING. VOL. 28, NO. 2, MARCH 1990 A Heuristic Algorithm For the Bistatic Radar Cross

    E-print Network

    Broschat, Shira Lynn

    Algorithm For the Bistatic Radar Cross Section For Random Rough Surface Scattering Abstract-In this paper we [7], [8]. Unfor- tunately, the equations for the bistatic radar cross section are not reciprocal. In this paper we examine a simple heuristic algorithm for the bistatic radar cross section, based on the phase

  1. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors, parts 1 and 2

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1994-01-01

    Formulations for scattering from the coated plate and the coated dihedral corner reflector are included. A coated plate model based upon the Uniform Theory of Diffraction (UTD) for impedance wedges was presented in the last report. In order to resolve inaccuracies and discontinuities in the predicted patterns using the UTD-based model, an improved model that uses more accurate diffraction coefficients is presented. A Physical Optics (PO) model for the coated dihedral corner reflector is presented as an intermediary step in developing a high-frequency model for this structure. The PO model is based upon the reflection coefficients for a metal-backed lossy material. Preliminary PO results for the dihedral corner reflector suggest that, in addition to being much faster computationally, this model may be more accurate than existing moment method (MM) models. An improved Physical Optics (PO)/Equivalent Currents model for modeling the Radar Cross Section (RCS) of both square and triangular, perfectly conducting, trihedral corner reflectors is presented. The new model uses the PO approximation at each reflection for the first- and second-order reflection terms. For the third-order reflection terms, a Geometrical Optics (GO) approximation is used for the first reflection; and PO approximations are used for the remaining reflections. The previously reported model used GO for all reflections except the terminating reflection. Using PO for most of the reflections results in a computationally slower model because many integrations must be performed numerically, but the advantage is that the predicted RCS using the new model is much more accurate. Comparisons between the two PO models, Finite-Difference Time-Domain (FDTD) and experimental data are presented for validation of the new model.

  2. Cross Sections for Electron Collisions with Carbon Monoxide

    NASA Astrophysics Data System (ADS)

    Itikawa, Yukikazu

    2015-03-01

    Cross section data are collected and reviewed for electron collisions with carbon monoxide. Collision processes included are total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational and electronic states, ionization, and dissociation. For each process, recommended values of the cross sections are presented, when possible. The literature has been surveyed through to the end of 2013.

  3. Raman scattering cross section for N2O4.

    NASA Technical Reports Server (NTRS)

    Chen, C. J.; Wu, F.

    1971-01-01

    Measurement of the Raman scattering cross section for N2O4 at a Raman shift of 7.3 micron, using a Q-switched ruby laser as an excitation source. The cross section for N2 at a Raman shift of 4.3 micron was also measured and compared with the value given by Leonard (1970).

  4. Predicting long bone loading from cross-sectional geometry

    Microsoft Academic Search

    Daniel E. Lieberman; John D. Polk; Brigitte Demes

    2004-01-01

    Long bone loading histories are com- monly evaluated using a beam model by calculating cross- sectional second moments of areas (SMAs). Without in vivo strain data, SMA analyses commonly make two ex- plicit or implicit assumptions. First, while it has long been known that axial compression superimposed on bending shifts neutral axes away from cross-sectional area cen- troids, most analyses

  5. PHOTON-PRODUCING AND NEUTRON ACTIVATION CROSS SECTIONS

    Microsoft Academic Search

    1959-01-01

    A tabulation of photon-preducing and neutron activation cross sections ; is presented primarily for use in analyzing secondary gamma emission and foil ; activities. It is intended to supplement the information currently available. ; Data are included for certain cross sections of the following elements: aluminum, ; beryllium, copper, iron, gold, lead, manganese, oxygen, and sulfur. (auth);

  6. ENERGY DEPENDENCE OF FAST-NEUTRON ACTIVATION CROSS SECTIONS

    Microsoft Academic Search

    A. E. Johnsrud; M. G. Silbert; H. H. Barschall

    1959-01-01

    Fast-neutron capture cross sections of 24 nuclides ranging from A = 51 ; to A = 197 were measured by an activation method, in the neutron energy region ; from 0.15 to 6.2 Mev. The neutron energy spreads were of the order of 0.1 Mev so ; that cross sections averaged over many energy levels of the compound nucleus were

  7. Thermal neutron activation cross sections for Kr and Xe isotopes

    Microsoft Academic Search

    E. Kondaiah; N. Ranakumar; R. W. Fink

    1968-01-01

    Quinol-clathrates of Kr and Xe have been used as solid targets for neutron activation for the first time, and 16 (n, gamma) cross sections have been determined with thermal neutrons. The epithermal neutron contribution has been taken into account by irradiating Cd covered samples. Four isomer cross-section ratios for Xe isotopes and one for Kr have also been obtained. In

  8. Molecular collision cross sections and vibrational relaxation in carbon dioxide

    Microsoft Academic Search

    R. Marriott

    1964-01-01

    A numerical method, previously developed for the calculation of partial cross sections for the collisional excitation of molecular vibrational states, has been extended to make proper allowance for the effect of the repulsive centrifugal potential term on the matrix transition elements. This treatment of molecular collisions has been applied to a study of vibrational relaxation in carbon dioxide. Cross sections

  9. SUPPLEMENT 1 TO APEX 515, CROSS SECTIONS FOR REACTOR ANALYSIS

    Microsoft Academic Search

    1959-01-01

    Since the publication of APEX 515, Cross Sections for Reactor ; Analysis,'I new records were added to the IBM 704 nuclear data tape. The purpose ; of this supplement is to acquaint the users of the nuclear data tape with the ; latest additions and to document the cross section data. The new or revised ; records pertain to the

  10. Neutron Capture Cross Sections: From Theory to Experiments and Back

    SciTech Connect

    Mengoni, A. [CERN, CH-1211 Geneva 23 (Switzerland); ENEA, Via Don Fiammelli, 2 - 40129 Bologna (Italy)

    2005-05-24

    The method for an experimental determination of the stellar enhancement factor for the cross section of the 151Sm(n,{gamma}) reaction process is proposed. This study offered the pretext for an excursus on the interconnections between capture and dissociation reactions and the interplay between theory and experiments in the determination of neutron capture cross sections.

  11. Neutron Capture Cross Sections: From Theory to Experiments and Back

    Microsoft Academic Search

    Alberto Mengoni

    2005-01-01

    The method for an experimental determination of the stellar enhancement factor for the cross section of the 151Sm(n,gamma) reaction process is proposed. This study offered the pretext for an excursus on the interconnections between capture and dissociation reactions and the interplay between theory and experiments in the determination of neutron capture cross sections.

  12. PRELIMINARY LES OVER A HYPERSONIC ELLIPTICAL CROSS-SECTION CONE

    E-print Network

    Martín, Pino

    PRELIMINARY LES OVER A HYPERSONIC ELLIPTICAL CROSS-SECTION CONE M.P. MARTIN Mechanical. The characteristics of the hypersonic flow around an elliptical- cross section cone and the computational code of transitional and turbulent flows are not fully understood. This is especially true in the hypersonic regime

  13. Radiation pressure cross-sections of fluffy interstellar grains

    Microsoft Academic Search

    R. Saija; M. A. Iatì; A. Giusto; F. Borghese; P. Denti; S. Aiello; C. Cecchi-Pestellini

    2003-01-01

    We computed, through the transition matrix method, the radiation pressure cross-sections of cosmic dust grains modelled as aggregates (clusters) of spheres of appropriate geometry. The calculation is performed without resorting to any approximation and with a computational effort that is noticeably lighter than the one required by other methods. Our results show that radiation pressure cross-sections decrease with increasing particle

  14. First measurement of the charged current cross section at HERA

    Microsoft Academic Search

    T. Ahmed; V. Andreev; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; J. Bán; P. Baranov; E. Barrelet; W. Bartel; M. Barth; U. Bassler; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; G. Bertrand-Coremans; M. Besançon; P. Biddulph; J. C. Bizot; V. Blobel; K. Borras; V. Boudry; A. Braemer; F. Brasse; W. Braunschweig; V. Brisson; D. Bruncko; C. Brune; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; D. G. Cussans; J. Cvach; S. Dagoret; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; K. Daum; M. David; E. Deffur; B. Delcourt; L. del Buono; A. de Roeck; E. de Wolf; C. Dollfus; J. D. Dowell; H. B. Dreis; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; H. Ehrlichmann; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; J. Ferencei; F. Ferrarotto; K. Flamm; W. Flauger; M. Fleischer; M. Flieser; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; M. Gebauer; A. Gellrich; H. Genzel; R. Gerhards; U. Goerlach; L. Goerlich; N. Gogitidze; M. Goldberg; D. Goldner; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; G. Grindhammer; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; M. Hampel; E. M. Hanlon; M. Hapke; W. J. Haynes; J. Heatherington; V. Hedberg; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladký; K. C. Hoeger; M. Höppner; Ph. Huet; H. Hufnagel; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; J. Janoth; T. Jansen; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; D. Kant; S. Kazarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; M. Krüner-Marquis; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; D. Lacour; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; P. Lanius; J. F. Laporte; A. Lebedev; C. Leverenz; S. Levonian; Ch. Ley; A. Lindner; G. Lindström; F. Linsel; J. Lipinski; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; D. Lüke; N. Magnussen; E. Malinovski; S. Mani; P. Marage; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; V. Milone; D. Milstead; F. Moreau; J. V. Morris; G. Müller; P. Murín; V. Nagovizin; B. Naroska; Th. Naumann; G. Nawrath; P. R. Newman; D. Newton; D. Neyret; H. K. Nguyen; F. Niebergall; C. Niebuhr; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg-Werther; H. Oberlack; U. Obrock; J. E. Olsson; A. Panitch; C. Pascaud; G. D. Patel; E. Peppel; E. Perez; J. P. Phillips; Ch. Pichler; D. Pitzl; G. Pope; S. Prell; R. Prosi; G. Rädel; F. Raupach; P. Reimer; S. Reinshagen; P. Ribarics; V. Riech; J. Riedlberger; S. Riess; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; K. Rosenbauer; A. Rostovtsev; C. Royon; K. Rüter; M. Ruffer; S. Rusakov; K. Rybicki; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; A. Schöning; V. Schröder; M. Schulz; B. Schwab; A. Schwind; U. Seehausen; F. Sefkow; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; Y. Soloviev; H. Spitzer; P. Staroba; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; J. Stiewe; U. Stösslein; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; S. Tapprogge; R. E. Taylor; V. Tchernyshov; C. Thiebaux; G. Thompson; I. Tichomirov; P. Truöl; J. Turnau; J. Tutas; A. Usik; S. Valkar; A. Valkarova; C. Vallée; P. van Esch; P. van Mechelen; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; G. Villet; K. Wacker; A. Wagener; I. W. Walker; A. Walther; G. Weber; M. Weber; D. Wegener; A. Wegner; H. P. Wellisch; L. R. West; S. Willard; M. Winde; G.-G. Winter; Th. Wolff; A. E. Wright; E. Wünsch; N. Wulff; T. P. Yiou; J. Zácek; Z. Zhang; M. Zimmer; W. Zimmermann; F. Zomer; K. Zuber

    1994-01-01

    The cross section of the charged current process e-p --> ve + hadrons is measured at HERA for transverse momenta of the hadron system larger than 25 GeV. The size of the cross section exhibits the W propagator. Supported by the Swiss National Science Foundation.

  15. Total elastic scattering cross sections for metastable argon on xenon

    Microsoft Academic Search

    J. Li; M. Faxas; J. W. Sheldon; K. A. Hardy

    1994-01-01

    The interaction potential between metastable argon (Ar*) and xenon has been determined by a measurement of the velocity dependence of the total elastic-scattering cross section for the reaction Ar*+Xe. The cross sections have been corrected for the inelastic contribution to the reaction. The potential parameters have been determined by comparing the data with potential parameters calculated with both semiclassical and

  16. Analysis of cross sections using various nuclear potential

    SciTech Connect

    Aziz, Azni Abdul [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Kulliyah of Science, International Islamic University Malaysia, 25200 Kuantan (Malaysia); Quantum Science Center, Faculty of Science, University of Malaya, 50603 Kuala Lump (Malaysia); Kassim, Hasan Abu [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Quantum Science Center, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Institute of Space Science, Universiti Kebangsaan Malaysia, 43600 Bangi, Se (Malaysia); Yusof, Norhasliza [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Quantum Science Center, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Muhammad Zamrun, F. [Quantum Science Center, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Jurusan Fisika FMIPA, Universitas Haluoleo Kendari, Sulawesi Tenggara, J3232 (Indonesia)

    2014-05-02

    The relevant astrophysical reaction rates which are derived from the reaction cross sections are necessary input to the reaction network. In this work, we analyse several theoretical models of the nuclear potential which give better prediction of the cross sections for some selected reactions.

  17. Single-Top Cross Section Measurements at ATLAS

    E-print Network

    P. Ryan; for the ATLAS Collaboration

    2009-10-20

    The single-top production cross section is one third that of the top-pair production cross section at the LHC. During the first year of data taking, the determination of the major contributions to the total single-top cross section should be achievable. Comparisons between the measured cross sections and the theoretical predictions will provide a crucial test of the standard model. These measurements should also lead to a direct measurement of |V_tb| with a precision at the level of a few percent. In addition, they will probe for new physics via the search for evidence of anomalous couplings to the top quark and measurements of additional bosonic contributions to single-top production. Methods developed to optimize the selection of single-top events in the three production channels are presented and the potential for the cross section measurements is established.

  18. Anomalously large neutron capture cross sections: a random phenomenon?

    E-print Network

    Carlson, B V; Kerman, A K

    2015-01-01

    We discuss the existence of huge thermal neutron capture cross sections in several nuclei. The values of the cross sections are several orders of magnitude bigger than expected at these very low energies. We lend support to the idea that this phenomenon is random in nature and is similar to what we have learned from the study of parity violation in the actinide region. The idea of statistical doorways is advanced as a unified concept in the delineation of large numbers in the nuclear world. The average number of maxima per unit mass, $$ in the capture cross section is calculated and related to the underlying cross section correlation function and found to be $ = \\frac{3}{\\pi \\sqrt{2}\\gamma_{A}}$, where $\\gamma_{A}$ is a characteristic mass correlation width which designates the degree of remnant coherence in the system. We trace this coherence to nucleosynthesis which produced the nuclei whose neutron capture cross sections are considered here.

  19. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    NASA Technical Reports Server (NTRS)

    Nicovich, J. M.; Wine, P. H.

    1988-01-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  20. An electron impact cross section set for CHF3

    NASA Astrophysics Data System (ADS)

    Kushner, Mark J.; Zhang, Da

    2000-09-01

    Trifluoromethane, CHF3, is used for plasma etching of silicon compounds for microelectronics fabrication, and so there is interest in developing computer models for plasmas sustained in CHF3. Recent measurements of electron swarm parameters, and electron impact dissociation and ionization cross sections, have provided a sufficient basis to develop a working electron impact cross section set for CHF3. Such a cross section set is reported here. We found that increased energy losses from dissociative electronic excitation processes were required to reproduce experimental ionization coefficients. The cross sections for attachment are small with there being some uncertainty in their magnitude at low energies. The cross sections were used in a plasma equipment model for an inductively coupled plasma reactor and compared to discharges sustained in C2F6. For otherwise identical operating conditions, plasmas sustained in CHF3 had higher electron and lower negative ion densities.

  1. Fission cross section measurements of actinides at LANSCE

    SciTech Connect

    Tovesson, Fredrik [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL

    2010-01-01

    Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications. By combining measurement at two LANSCE facilities, Lujan Center and the Weapons Neutron Research center (WNR), differential cross sections can be measured from sub-thermal energies up to 200 MeV. Incident neutron energies are determined using the time-of-flight method, and parallel-plate ionization chambers are used to measure fission cross sections relative to the {sup 235}U standard. Recent measurements include the {sup 233,238}U, {sup 239,242}Pu and {sup 243}Am neutron-induced fission cross sections. In this paper preliminary results for cross section data of {sup 243}Am and {sup 233}U will be presented.

  2. Analytical approximations for x-ray cross sections III

    SciTech Connect

    Biggs, F; Lighthill, R

    1988-08-01

    This report updates our previous work that provided analytical approximations to cross sections for both photoelectric absorption of photons by atoms and incoherent scattering of photons by atoms. This representation is convenient for use in programmable calculators and in computer programs to evaluate these cross sections numerically. The results apply to atoms of atomic numbers between 1 and 100 and for photon energiesgreater than or equal to10 eV. The photoelectric cross sections are again approximated by four-term polynomials in reciprocal powers of the photon energy. There are now more fitting intervals, however, than were used previously. The incoherent-scattering cross sections are based on the Klein-Nishina relation, but use simpler approximate equations for efficient computer evaluation. We describe the averaging scheme for applying these atomic results to any composite material. The fitting coefficients are included in tables, and the cross sections are shown graphically. 100 graphs, 1 tab.

  3. A Robust Algorithm for Automatic Target Recognition Using Passive Lisa M. Ehrman and Aaron D. Lanterman

    E-print Network

    Lanterman, Aaron

    to existing passive radar systems. We do so by comparing the radar cross section (RCS) of detected targets to the precom- puted RCS of known targets in the target class. The precomputed RCS of the targets comprising- pabilities to existing passive radar systems, using RCS as the key information for classification. Since RCS

  4. RCS: An Intelligent Agent Architecture

    Microsoft Academic Search

    Jim Albus; Tony Barbera; Craig Schlenoff

    RCS (Real-time Control System) is an intelligent agent architecture designed to enable any level of intelligent behavior, up to and including human levels of performance. RCS was inspired 30 years ago by a theoretical model of the cerebellum, the portion of the brain responsible for fine motor coordination and control of conscious motions. It was originally designed for sensory-interactive goal-

  5. Cross-section adjustment techniques for BWR adaptive simulation

    NASA Astrophysics Data System (ADS)

    Jessee, Matthew Anderson

    Computational capability has been developed to adjust multi-group neutron cross-sections to improve the fidelity of boiling water reactor (BWR) modeling and simulation. The method involves propagating multi-group neutron cross-section uncertainties through BWR computational models to evaluate uncertainties in key core attributes such as core k-effective, nodal power distributions, thermal margins, and in-core detector readings. Uncertainty-based inverse theory methods are then employed to adjust multi-group cross-sections to minimize the disagreement between BWR modeling predictions and measured plant data. For this work, measured plant data were virtually simulated in the form of perturbed 3-D nodal power distributions with discrepancies with predictions of the same order of magnitude as expected from plant data. Using the simulated plant data, multi-group cross-section adjustment reduces the error in core k-effective to less than 0.2% and the RMS error in nodal power to 4% (i.e. the noise level of the in-core instrumentation). To ensure that the adapted BWR model predictions are robust, Tikhonov regularization is utilized to control the magnitude of the cross-section adjustment. In contrast to few-group cross-section adjustment, which was the focus of previous research on BWR adaptive simulation, multigroup cross-section adjustment allows for future fuel cycle design optimization to include the determination of optimal fresh fuel assembly designs using the adjusted multi-group cross-sections. The major focus of this work is to efficiently propagate multi-group neutron cross-section uncertainty through BWR lattice physics calculations. Basic neutron cross-section uncertainties are provided in the form of multi-group cross-section covariance matrices. For energy groups in the resolved resonance energy range, the cross-section uncertainties are computed using an infinitely-dilute approximation of the neutron flux. In order to accurately account for spatial and energy resonance self-shielding effects, the multi-group cross-section covariance matrix has been reformulated to include the uncertainty in resonance correction factors, or self-shielding factors, which are used to calculate the self-shielded multi-group cross-sections used in the lattice physics neutron transport model. This is shown to change the U-238 capture cross-section uncertainty contribution to Beginning-of-Life (BOL) lattice k-infinity by 14% (i.e. 0.291% relative standard deviation in k-infinity (self-shielded) compared to 0.255% (infinitely-dilute)). Using the reformulated multi-group cross-section covariance matrix, Efficient Subspace Methods (ESM) are used to propagate multi-group cross-section uncertainty through the lattice physics calculation. ESM algorithms have been developed by H. S. Abdel-Khalik and P. J. Turinsky to calculate low-rank approximations to large, dense sensitivity and covariance matrices used in data adjustment and uncertainty propagation applications. Using ESM, the singular value spectrum of the multi-group cross-section covariance matrix reveals an effective rank of the order of 103. Using this singular value decomposition of the multigroup cross-section covariance matrix reduces the number of lattice physics calculations per lattice from ˜107 to ˜10 3. In addition, a BOL sensitivity analysis using generalized perturbation theory at the lattice physics level is shown to further reduce the rank by a factor of 5.

  6. Low RCS patch array antenna with electromagnetic bandgap using a conducting polymer

    Microsoft Academic Search

    Hong-Kyu Jang; Jae-Hwan Shin; Chun-Gon Kim

    2010-01-01

    This paper provides a radar absorbing method to reduce the radar cross section of the patch array antennas without any loss of antenna performances. The method was based upon the electromagnetic bandgap absorber using a conducting polymer. First, the patch array antenna with a central frequency of 3.0 GHz was designed. Then, the EBG patterns were also designed that had

  7. From a different perspective: principles, practice and potential of bistatic radar

    Microsoft Academic Search

    H. D. Griffiths

    2003-01-01

    Bistatic radar systems have been studied and built since the earliest days of radar. They have the advantages that the receivers are passive, and hence undetectable. The receiving systems are also potentially simple and cheap. Bistatic radar may have a counter-stealth capability, since target shaping to reduce monostatic RCS will in general not reduce the bistatic RCS. In spite of

  8. Electron impact rotationally elastic total cross section for formamide

    SciTech Connect

    Vinodkumar, Minaxi, E-mail: minaxivinod@yahoo.co.in [V P and R P T P Science College, Vallabh Vidyanagar 388120 (India); Limbachiya, Chetan, E-mail: chetanlimbachiya2@yahoo.com [Department of Applied Physics, The M.S. University of Baroda, Vadodara 390001 (India); Desai, Hardik, E-mail: hardikdesai.phy@gmail.com; Vinodkumar, P. C., E-mail: p.c.vinodkumar@gmail.com [Department of Physics, Sardar Patel University, Vallabh Vidyanagar 388120 (India)

    2014-09-28

    This paper reports computational results of the total cross sections for electron impact on formamide (HCONH?) over a wide range of energies from 0.01 eV to 5 keV. Total cross sections over such a wide range are reported for the first time as the earlier reported data is up to maximum of 12 eV. Below ionization threshold of the target, we performed ab initio calculations using UK molecular R-Matrix code within static, exchange plus polarization (SEP), and close coupling approximations. Twenty eight target states are included in close coupling formalism. Total 350 channels and 2410 configuration state functions are included in the calculations. We observe a ?* shape resonance at 3.41 eV and a ?* resonance at 15.3 eV as against similar resonances reported at 3.77 eV and 14.9 eV, respectively, by Goumans et al. [J. Chem. Theory Comput. 5, 217 (2009)] using SEP model. The cross sections at higher energies are evaluated using the spherical complex optical potential formalism. The two methods are found to be consistent with a smooth cross over at 18 eV. The vertical excitation energies, electronic excitation cross sections, differential cross sections, momentum transfer, and total cross sections are computed. In absence of experimental data, we compared our computed total cross sections with available other theoretical results.

  9. Nuclear cross sections for heavy charged-particle transport

    SciTech Connect

    Townsend, L.W.

    1986-01-01

    The need to develop suitable methods for describing the interactions and transport of high-energy, heavy charged particles through extended matter is important for a variety of applications including astronaut exposure to space radiations, spacecraft shielding, radiobiological studies, accelerator shield design, and clinical uses in cancer therapy. Crucial to satisfactorily to these calculations are accurate values for the absorption and fragmentation cross sections. Unfortunately, experimental data for these cross sections are sparse. Hence, the theoretical and semiempirical methods must be utilized to provide the necessary cross-section values and is illustrated here. Representative results for carbon-carbon collisions are listed. Presented are absorption cross sections at several energies and fragmentation cross sections at 2.1 GeV/nucleon. The cross sections include experimental results and predictions from parameterizations and quantum-mechanical models. For absorption cross sections, the energy-independent parameterization fails at low energies, whereas the optical model calculations and energy-dependent parameterization results are in good agreement with the experimental data. For the fragmentation, reasonable agreement is obtained for some isotopes; however, large disagreements exist for others.

  10. Cross Section Sensitivity and Propagated Errors in HZE Exposures

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Wilson, John W.; Blatnig, Steve R.; Qualls, Garry D.; Badavi, Francis F.; Cucinotta, Francis A.

    2005-01-01

    It has long been recognized that galactic cosmic rays are of such high energy that they tend to pass through available shielding materials resulting in exposure of astronauts and equipment within space vehicles and habitats. Any protection provided by shielding materials result not so much from stopping such particles but by changing their physical character in interaction with shielding material nuclei forming, hopefully, less dangerous species. Clearly, the fidelity of the nuclear cross-sections is essential to correct specification of shield design and sensitivity to cross-section error is important in guiding experimental validation of cross-section models and database. We examine the Boltzmann transport equation which is used to calculate dose equivalent during solar minimum, with units (cSv/yr), associated with various depths of shielding materials. The dose equivalent is a weighted sum of contributions from neutrons, protons, light ions, medium ions and heavy ions. We investigate the sensitivity of dose equivalent calculations due to errors in nuclear fragmentation cross-sections. We do this error analysis for all possible projectile-fragment combinations (14,365 such combinations) to estimate the sensitivity of the shielding calculations to errors in the nuclear fragmentation cross-sections. Numerical differentiation with respect to the cross-sections will be evaluated in a broad class of materials including polyethylene, aluminum and copper. We will identify the most important cross-sections for further experimental study and evaluate their impact on propagated errors in shielding estimates.

  11. Review of electron impact excitation cross sections for copper atom

    SciTech Connect

    Winter, N.W.; Hazi, A.U.

    1982-02-01

    Excitation of atomic copper by electron impact plays an important role in the copper vapor laser and accurate cross sections are needed for understanding and modeling laser performance. During the past seven years, there have been several attempts to normalize the relative elastic and inelastic cross sections measured by Trajmar and coworkers. However, each of these efforts have yielded different cross sections, and the uncertainty in the correct normalization of the data has been a source of confusion and concern for the kinetic modeling efforts. This difficulty has motivated us to review previous work on the electron impact excitation of copper atom and to perform new calculations of the inelastic cross sections using the impact parameter method. In this memorandum we review the previous attempts to normalize the experimental data and provide a critical assessment of the accuracy of the resulting cross sections. We also present new theoretical cross sections for the electron impact excitation of the /sup 2/S ..-->.. /sup 2/P/sup 0/ and /sup 2/S ..-->.. /sup 2/D transitions in copper. When the experimental cross sections are renormalized to the results of the impact parameter calculations, they are a factor of three smaller than those published in the latest paper of Trajmar et. al. At impact energies above 60 eV the excitation cross sections obtained with the impact parameter method agree well with the results of the very recent, unpublished, close-coupling calculations of Henry. This agreement suggests that the present normalization of the experimental cross sections is probably the most reliable one obtained to date.

  12. Total elastic cross sections for metastable argon on xenon

    SciTech Connect

    Barrios, A.; Faxas, M.; Li, J. [and others

    1993-05-01

    Total scattering cross sections have been measured using single beam attenuation of a metastable argon atom mixed {sup 3}P{sub 2,0} beam scattered from xenon. After relative velocity and angular corrections are made, preliminary data give a total scattering cross section of 700 {plus_minus} 65 {Angstrom}{sup 2} (at a relative velocity of 1000 m/s) is found. Earlier experiments give a total cross section for metastable argon atoms scattered from xenon of approximately 754 {Angstrom}{sup 2} and 580 {Angstrom}{sup 2} (at 1000 m/s).

  13. Actinide Neutron-Induced Fission Cross Section Measurements At LANSCE

    SciTech Connect

    Tovesson, F.; Laptev, A. B. [Los Alamos National Laboratory, Los Alamos NM 87545 (United States); Hill, T. S. [Idaho National Laboratory, Idaho Falls ID 83415 (United States)

    2011-06-01

    Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications in a wide energy range from sub thermal energies up to 200 MeV. Parallel-plate ionization chambers are used to measure fission cross sections ratios relative to the {sup 235}U standard while incident neutron energies are determined using the time-of-flight method. Recent measurements include the {sup 233,238}U, {sup 239-242}Pu and {sup 243}Am neutron-induced fission cross sections. Obtained data are presented in comparison with existing evaluations and previous data.

  14. Cross section to multiplicity ratios at very high energy

    NASA Astrophysics Data System (ADS)

    Block, M. M.; Stodolsky, L.

    2014-06-01

    Recent data from the LHC makes it possible to examine an old speculation that at very high energy the total multiplicity and the cross section in elementary particle interactions vary in parallel with energy. Using fits incorporating the new data, it appears that the ratios of the total, elastic, and inelastic cross sections to the average multiplicity N can in fact approach constants at very high energy. The approach to the limit is however quite slow for the total and inelastic cross sections and is not yet reached at LHC energies. The elastic ratio ?el/N at 7 TeV, however, is not far from its asymptotic value.

  15. Capabilities of radar as they might relate to entomological studies

    NASA Technical Reports Server (NTRS)

    Skolnik, M. I.

    1979-01-01

    A tutoral background of radar capabilities and its potential for insect research is provided. The basic principles and concepts of radar were reviewed. Information on current radar equipment was examined. Specific issues related to insect research included; target cross-section, radar frequency, tracking target recognition and false alarms, clutter reduction, radar transmitter power, and ascertained atmospheric processes.

  16. Top quark pair cross section prospects in ATLAS

    E-print Network

    Andrei Gaponenko; for the ATLAS Collaboration

    2009-10-20

    The observation of the top quark will be an important milestone in ATLAS. This talk reviews methods that ATLAS plans to use to observe the top quark pair production process and measure its cross section.

  17. Measurement of the Z ? ?? cross section with the ATLAS detector

    SciTech Connect

    Aad, G. [Albert-Ludwigs-Universitat, Freiburg (Germany). Fakultat fur Mathematik und Physik; Abbott, B. [Univ. of Oklahoma, Norman, OK (United States). Homer L. Dodge Dept. of Physics and Astronomy; Abdallah, J. [Universitat Autonoma de Barcelona and ICREA, Barcelona (Spain). Institut de Fisica d' Altes Energies; Abdelalim, A. A. [Universite de Geneve, Geneva (Switzerland). Section de Physique; Abdesselam, A. [Oxford Univ., Oxford (United Kingdom). Dept. of Physics; Abdinov, O. [Academy of Sciences, Baku (Azerbaijan). Institute of Physics; Abi, B. [Oklahoma State Univ., Stillwater, OK (United States). Dept. of Physics; Abolins, M. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Abramowicz, H. [Tel Aviv Univ., Tel Aviv (Israel). Raymond and Beverly Sackler School of Physics and Astronomy; Abreu, H. [Univ. Paris-Sud, Orsay (France). LAL; Acerbi, E. [Universita di Milano, Milano (Italy). Dipartimento di Fisica; INFN Sezione di Milano, Milano (Italy); Acharya, B. S. [Collegato di Udine (Italy). INFN Gruppo; ICTP, Trieste (Italy); Adams, D. L. [Brookhaven National Lab. (BNL), Upton, NY (United States). Physics Dept.; Addy, T. N. [Hampton Univ., Hampton, VA (United States); Dept. of Physics; Adelman, J. [Yale Univ., New Haven, CT (United States). Dept. of Physics; Aderholz, M. [Werner-Heisenberg-Institut, Muchen (Germany). Max-Planck-Institut fur Physik; Adomeit, S. [Ludwig Maximilian Univ., Munich (Germany). Fakultat fur Physik; Adragna, P. [Queen Mary Univ. of London, London (United Kingdom). Dept. of Physics; Adye, T. [Rutherford Appleton Laboratory, Didcot (United Kingdom). Particle Physics Dept.; Aefsky, S. [Brandeis Univ., Waltham, MA (United States). Dept. of Physics; Aguilar-Saavedra, J. A. [Universidad de Granada, Granada (Spain). Departamento de Fisica Teorica y del Cosmos and CAFPE; Siegrist, James L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-12-01

    The Z ? ?? cross section is measured with the ATLAS experiment at the LHC in four different final states determined by the decay modes of the {tau} leptons: muon-hadron, electron-hadron, electron-muon, and muon-muon. The analysis is based on a data sample corresponding to an integrated luminosity of 36 pb?¹, at a proton-proton center-of-mass energy of ?s = 7 TeV. Cross sections are measured separately for each final state in fiducial regions of high detector acceptance, as well as in the full phase space, over the mass region 66-116 GeV. The individual cross sections are combined and the product of the total Z production cross section and Z ? ?? branching fraction is measured to be 0.97 ± 0.07(stat) ± 0.06(syst) ± 0.03(lumi) nb, in agreement with next-to-next-to-leading order calculations.

  18. Electron impact ionization cross sections for C60 fullerene

    NASA Astrophysics Data System (ADS)

    Pal, Satyendra; Anshu; Singh, C.

    2011-06-01

    We have extended and generalized the modified Jain-Khare (JK) semiempirical formalism to the evaluation of partial differential and partial integral ionization cross sections for fullerenes. The differential cross sections corresponding to the production of singly, doubly and triply charged cations in the electron impact ionization of C60 were evaluated at incident electron energies of 100 and 200 eV. The partial integral ionization cross sections calculated in the energy range varying from ionization thresholds to 1000 eV revealed satisfactory agreement with the available experimental and theoretical data. The ionization rate coefficients corresponding to the various cations have also been evaluated using the presently calculated ionization cross sections and Maxwell-Boltzmann energy distributions.

  19. Stellar (n, ?)-cross sections of short-lived nuclei.

    NASA Astrophysics Data System (ADS)

    Käppeler, F.

    Stellar neutron capture cross sections are the essential input for investigating the element production via the slow neutron capture process (s-process). With the availability of accurate cross sections for the stable s-process isotopes, analyses of the abundance patterns in the various branchings of the s-process flow require also reliable cross sections for unstable nuclei with stellar half-lives down to a few days. This contribution deals with the question to which extent existing techniques can be applied for these cases, and whether a future radioactive ion beam could be used for the preparation of suited samples. As an example, recent measurements of the stellar (n, ?) cross section of 147Pm (t1/2 = 2.6 yr) are discussed.

  20. Absolute two-photon excitation cross-sections in NO

    NASA Technical Reports Server (NTRS)

    Burris, J.; Mcgee, T.; Mcilrath, T.

    1984-01-01

    A technique has been developed which allows the determination of a two-photon absorption cross-section to be made relative to the Raman scattering cross-section in nitrogen. Spatial and temporal effects associated with the lasers are ratioed out to give a result independent of laser parameters. The necessary theory to extract a cross-section from the measured ratio of a Coherent Anti-Stokes Raman Scattering (CARS) signal in N2 to a four-wave mixing signal in NO has been developed. The technique has been demonstrated on the R(22) + S(12) (J-double-prime = 9 1/2) line in NO and a cross-section of (2.9 + or - 1.8) x 10 to the -49th (cm to the 4th power)-s was determined. This technique appears to be applicable to a number of other diatomic molecules.

  1. 4. DETAIL VIEW OF CROSS SECTION OF STRUCTURE, SHOWING EXTERIOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF CROSS SECTION OF STRUCTURE, SHOWING EXTERIOR FACINGS LINED WITH RUBBLE BACKING AND EARTH INFILL, LOOKING EAST - Rock Wall, North side of Battle Creek Canyon, Shingletown, Shasta County, CA

  2. 11. DETAIL OF DITCH CROSS SECTION WITH VISUAL SCALES. DITCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. DETAIL OF DITCH CROSS SECTION WITH VISUAL SCALES. DITCH WAS BISECTED BY LOCAL DRAINAGE; VIEW TO SOUTH. - Keefe-McDerby Mine Ditch, East of East Bidwell Street between Clarksville Road & Highway 50, Folsom, Sacramento County, CA

  3. Viscosity cross sections for the heavy noble gases

    NASA Astrophysics Data System (ADS)

    McEachran, Robert P.; Stauffer, Allan Daniel

    2015-04-01

    We have calculated viscosity cross sections for argon, krypton and xenon from zero to 1 keV using the phase shifts from our previous publication [R.P. McEachran, A.D. Stauffer, Eur. Phys. J. D 68, 153 (2014)] which presented total elastic and momentum transfer cross sections for these gases. As previously, we present simple analytic fits to our results to aid in modelling plasmas containing these atoms. By using the current results and those in reference [R.P. McEachran, A.D. Stauffer, Eur. Phys. J. D 68, 153 (2014)] the first two `partial cross sections' used in the general moment method of solving the Boltzmann equation can be obtained. The agreement of our viscosity cross sections with experimentally derived results indicates the overall reliability of our calculations.

  4. Hadronic cross sections, elastic slope and physical bounds

    SciTech Connect

    Fagundes, D. A.; Menon, M. J. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas SP (Brazil)

    2013-03-25

    An almost model-independent parametrization for the ratio of the total hadronic cross section to elastic slope is discussed. Its applicability in studies of asymptotia and analyses of extensive air shower in cosmic-ray physics is also outlined.

  5. On the cyclo-synchrotron cross-section

    NASA Astrophysics Data System (ADS)

    Gliozzi, M.; Bodo, G.; Ghisellini, G.; Trussoni, E.

    1996-06-01

    The study of the synchrotron and cyclotron absorption processes and their relative cross-sections, recently analysed by Ghisellini & Svensson, is extended to the case of photons propagating along the direction of the magnetic field. In the relativistic regime we follow a quantum approach, which requires first the derivation of the particle emissivity for the assumed configuration. The expression for the cross-section coincides with that obtained through a classical treatment of the problem in the non-relativistic regime. In the frequency range where absorption is important, the cross-section is larger than the Thomson cross-section by several orders of magnitude, implying a strong coupling between radiation and magnetized plasma. The possible atrophysical implications of this process are briefly discussed; in particular, in a magnetized plasma the Eddington luminosity for synchrotron interaction can be much lower than the standard value.

  6. 30 CFR 779.25 - Cross sections, maps, and plans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...SURFACE MINING PERMIT APPLICATIONS-MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES § 779.25 Cross sections...assistance from experts in related fields such as landscape architecture, and shall be updated as required by the regulatory...

  7. 56. CROSS SECTIONS OF CANAL AND TUNNELS. POWER CANAL, SALT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. CROSS SECTIONS OF CANAL AND TUNNELS. POWER CANAL, SALT RIVER RESERVOIR Courtesy of U.S.G.S., Reclamation Service - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  8. ConcepTest: Cross-Sections of Plate Boundaries

    NSDL National Science Digital Library

    The map below shows the plate configurations along the western margin of North America. Which of the four diagrams on the right best represents a cross section through the outer layers of Earth along the line X-Y?

  9. ConcepTest: Cross-Section of Plate Boundaries

    NSDL National Science Digital Library

    The map below shows the plate configurations along the western margin of North America. Which of the four diagrams on the right best represents a cross section through the outer layers of Earth along the line X-Y?

  10. Dielectronic-Recombination Cross-Sections of Hydrogenlike Argon 

    E-print Network

    Dewitt, D. R.; Schneider, D.; Clark, M. W.; Chen, M. H.; Church, David A.

    1991-01-01

    Relative dielectronic-recombination cross sections for hydrogenlike argon are presented. The contributions of the KLL, KLM, KLN, KLO, and KLP groups of resonances are compared to theoretical calculations. The experimental method consists...

  11. Handbook of LHC Higgs Cross Sections: 2. Differential Distributions

    E-print Network

    LHC Higgs Cross Section Working Group; S. Dittmaier; C. Mariotti; G. Passarino; R. Tanaka; S. Alekhin; J. Alwall; E. A. Bagnaschi; A. Banfi; J. Blumlein; S. Bolognesi; N. Chanon; T. Cheng; L. Cieri; A. M. Cooper-Sarkar; M. Cutajar; S. Dawson; G. Davies; N. De Filippis; G. Degrassi; A. Denner; D. D'Enterria; S. Diglio; B. Di Micco; R. Di Nardo; R. K. Ellis; A. Farilla; S. Farrington; M. Felcini; G. Ferrera; M. Flechl; D. de Florian; S. Forte; S. Ganjour; M. V. Garzelli; S. Gascon-Shotkin; S. Glazov; S. Goria; M. Grazzini; J. -Ph. Guillet; C. Hackstein; K. Hamilton; R. Harlander; M. Hauru; S. Heinemeyer; S. Hoche; J. Huston; C. Jackson; P. Jimenez-Delgado; M. D. Jorgensen; M. Kado; S. Kallweit; A. Kardos; N. Kauer; H. Kim; M. Kovac; M. Kramer; F. Krauss; C. -M. Kuo; S. Lehti; Q. Li; N. Lorenzo; F. Maltoni; B. Mellado; S. O. Moch; A. Muck; M. Muhlleitner; P. Nadolsky; P. Nason; C. Neu; A. Nikitenko; C. Oleari; J. Olsen; S. Palmer; S. Paganis; C. G. Papadopoulos; T . C. Petersen; F. Petriello; F. Petrucci; G. Piacquadio; E. Pilon; C. T. Potter; J. Price; I. Puljak; W. Quayle; V. Radescu; D. Rebuzzi; L. Reina; J. Rojo; D. Rosco; G. P. Salam; A. Sapronov; J. Schaarschmidt; M. Schonherr; M. Schumacher; F. Siegert; P. Slavich; M. Spira; I. W. Stewart; W. J. Stirling; F. Stockli; C. Sturm; F. J. Tackmann; R. S. Thorne; D. Tommasini; P. Torrielli; F. Tramontano; Z. Trocsanyi; M. Ubiali; S. Uccirati; M. Vazquez Acosta; T. Vickey; A. Vicini; W. J. Waalewijn; D. Wackeroth; M. Warsinsky; M. Weber; M. Wiesemann; G. Weiglein; J. Yu; G. Zanderighi

    2012-01-15

    This Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent developments.

  12. Handbook of LHC Higgs Cross Sections: 2. Differential Distributions

    E-print Network

    Dittmaier, S; Passarino, G; Tanaka, R; Alekhin, S; Alwall, J; Bagnaschi, E A; Banfi, A; Blumlein, J; Bolognesi, S; Chanon, N; Cheng, T; Cieri, L; Cooper-Sarkar, A M; Cutajar, M; Dawson, S; Davies, G; De Filippis, N; Degrassi, G; Denner, A; D'Enterria, D; Diglio, S; Di Micco, B; Di Nardo, R; Ellis, R K; Farilla, A; Farrington, S; Felcini, M; Ferrera, G; Flechl, M; de Florian, D; Forte, S; Ganjour, S; Garzelli, M V; Gascon-Shotkin, S; Glazov, S; Goria, S; Grazzini, M; Guillet, J -Ph; Hackstein, C; Hamilton, K; Harlander, R; Hauru, M; Heinemeyer, S; Hoche, S; Huston, J; Jackson, C; Jimenez-Delgado, P; Jorgensen, M D; Kado, M; Kallweit, S; Kardos, A; Kauer, N; Kim, H; Kovac, M; Kramer, M; Krauss, F; Kuo, C -M; Lehti, S; Li, Q; Lorenzo, N; Maltoni, F; Mellado, B; Moch, S O; Muck, A; Muhlleitner, M; Nadolsky, P; Nason, P; Neu, C; Nikitenko, A; Oleari, C; Olsen, J; Palmer, S; Paganis, S; Papadopoulos, C G; Petersen, T C; Petriello, F; Petrucci, F; Piacquadio, G; Pilon, E; Potter, C T; Price, J; Puljak, I; Quayle, W; Radescu, V; Rebuzzi, D; Reina, L; Rojo, J; Rosco, D; Salam, G P; Sapronov, A; Schaarschmidt, J; Schonherr, M; Schumacher, M; Siegert, F; Slavich, P; Spira, M; Stewart, I W; Stirling, W J; Stockli, F; Sturm, C; Tackmann, F J; Thorne, R S; Tommasini, D; Torrielli, P; Tramontano, F; Trocsanyi, Z; Ubiali, M; Uccirati, S; Acosta, M Vazquez; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Warsinsky, M; Weber, M; Wiesemann, M; Weiglein, G; Yu, J; Zanderighi, G

    2012-01-01

    This Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent developments.

  13. Healthy Zero Energy Buildings (HZEB) Program Cross-Sectional

    E-print Network

    Healthy Zero Energy Buildings (HZEB) Program ­ Cross-Sectional Study of Contaminant Levels, Source Laboratory is an equal opportunity employer. #12;1 Final Report Healthy Zero Energy Buildings (HZEB) Program

  14. The contribution of diffusion to device upset cross sections

    NASA Technical Reports Server (NTRS)

    Patterson, J. D.; Edmonds, L. D.

    2002-01-01

    A novel technique incorporating carrier recombination, for determining the charge collection efficiency funcition is presented and applied to a realistic, 3-D, memory device to obtain the upset cross section as a function of LET and orientation of incidence.

  15. 8. VIEW OF CROSS SECTION OF THE EASTERNMOST WALL SEGMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF CROSS SECTION OF THE EASTERNMOST WALL SEGMENT THAT SHOWS THE TRENCHING AND 1960 PIPELINE CORRIDOR BETWEEN THE WALL SEGMENTS, LOOKING WEST-NORTHWEST - Rock Wall, North side of Battle Creek Canyon, Shingletown, Shasta County, CA

  16. Cross section dependence of event rates at neutrino telescopes

    E-print Network

    Marfatia, Danny; Seckel, D.; McKay, D. W.; Hussain, S.

    2006-10-20

    leaves the rate of upward events essentially unchanged. Details, such as detector depth and cross section inelasticity, can influence rates. Numerical estimates of upward shower, muon, and tau event rates in the IceCube detector confirm these results....

  17. Application of AWE Along with a Combined FEM/MoM Technique to Compute RCS of a Cavity-Backed Aperture in an Infinite Ground Plane Over a Frequency Range

    NASA Technical Reports Server (NTRS)

    Reddy, C.J.; Deshpande, M.D.

    1997-01-01

    A hybrid Finite Element Method (FEM)/Method of Moments (MoM) technique in conjunction with the Asymptotic Waveform Evaluation (AWE) technique is applied to obtain radar cross section (RCS) of a cavity-backed aperture in an infinite ground plane over a frequency range. The hybrid FEM/MoM technique when applied to the cavity-backed aperture results in an integro-differential equation with electric field as the unknown variable, the electric field obtained from the solution of the integro-differential equation is expanded in Taylor series. The coefficients of the Taylor series are obtained using the frequency derivatives of the integro-differential equation formed by the hybrid FEM/MoM technique. The series is then matched via the Pade approximation to a rational polynomial, which can be used to extrapolate the electric field over a frequency range. The RCS of the cavity-backed aperture is calculated using the electric field at different frequencies. Numerical results for a rectangular cavity, a circular cavity, and a material filled cavity are presented over a frequency range. Good agreement between AWE and the exact solution over the frequency range is obtained.

  18. Double differential cross sections of carbonyl sulfide molecule

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev; Sanju

    2013-06-01

    Partial and total double differential cross sections corresponding to various cations produced during the direct and dissociative electron ionization of carbonyl sulfide molecule have been calculated at fixed impinging electron energies 100 and 200eV by using modified Jain-Khare semi empirical approach. The calculation for double differential cross sections is made as a function of energy loss suffered by primary electron and angle of incident. To the best of our knowledge no other data is available for the comparison.

  19. Electron impact excitation cross sections for B III

    Microsoft Academic Search

    P. S. Ganas; M. Aryafar; L. P. Gately

    1983-01-01

    A realistic analytical central potential with two adjustable parameters is used to generate wavefunctions for the ground and excited states of doubly ionized boron. Generalized oscillator strengths and integrated cross sections from threshold up to 5 keV are calculated in the Born approximation for 2s-ns, 2s-np and 2s-nd excitations. Convenient analytic formulas for the cross sections are presented.

  20. Energy Dependence of Fast-Neutron Activation Cross Sections

    Microsoft Academic Search

    A. E. Johnsrud; M. G. Silbert; H. H. Barschall

    1959-01-01

    Fast-neutron capture cross sections of 24 nuclides ranging from A=51 to A=197 have been measured by an activation method, in the neutron energy region from 0.15 to 6.2 Mev. The neutron energy spreads were of the order of 0.1 Mev so that cross sections averaged over many energy levels of the compound nucleus were measured. Activities induced in samples by

  1. Derivation of capture cross section from quasielastic excitation function

    E-print Network

    V. V. Sargsyan; G. G. Adamian; N. V. Antonenko; P. R. S. Gomes

    2013-04-18

    The relationship between the quasielastic excitation function and the capture cross section is derived. The quasielastic data is shown to be a useful tool to extract the capture cross sections and the angular momenta of the captured systems for the reactions $^{16}$O+$^{144,154}$Sm,$^{208}$Pb, $^{20}$Ne+$^{208}$Pb, and $^{32}$S+$^{90,96}$Zr at near and above the Coulomb barrier energies.

  2. MINING INTEGRAL ACTINIDES CROSS SECTIONS FROM REACTOR DATA

    Microsoft Academic Search

    PUIGH RJ

    2009-01-01

    The conclusions of this paper are: (1) mining of actinide cross-sections from reactor data is a viable and inexpensive approach to confirm burn-up codes; (2) extensive data for actinides in Hanford test data ( 200 radiochemical analyses); (3) not only cross-section values and reaction rates can be established but also possible benchmark like data can be constructed to test and

  3. Cross-section adjustment techniques for BWR adaptive simulation

    Microsoft Academic Search

    Matthew Anderson Jessee

    2008-01-01

    Computational capability has been developed to adjust multi-group neutron cross-sections to improve the fidelity of boiling water reactor (BWR) modeling and simulation. The method involves propagating multi-group neutron cross-section uncertainties through BWR computational models to evaluate uncertainties in key core attributes such as core k-effective, nodal power distributions, thermal margins, and in-core detector readings. Uncertainty-based inverse theory methods are then

  4. The evaluation and application of redundant-cross-section covariances

    SciTech Connect

    Muir, D.W.

    1986-01-01

    Certain multigroup covariance libraries, notably COVFILS-2, omit all redundant (or summed) reactions on the grounds that the information content of a well-measured total cross section, for example, is implicitly contained in the covariances of the component, or partial, reactions that add up to the total. It is shown that, while redundant reactions can play an important role in cross-section and covariance evaluation, their emission from libraries intended for applications is justifiable. 3 refs.

  5. Photodissociation cross sections and rates for CH\\/+\\/ in interstellar clouds

    Microsoft Academic Search

    K. Kirby; W. G. Roberge; R. P. Saxon; B. Liu

    1980-01-01

    Photodissociation cross sections have been calculated for transitions arising from the ground state of CH(+) to three excited states of 1Sigma(+) symmetry accessible with photon energies not greater than 13.6 eV. Two of these dissociation channels have large cross sections and are therefore particularly relevant to the destruction of CH(+) in the interstellar medium. Photodissociation rates in the interstellar radiation

  6. New fragmentation cross sections for galactic cosmic-ray propagation

    Microsoft Academic Search

    J. S. George; R. A. Mewaldt; N. E. Yanasak; M. E. Wiedenbeck; J. J. Connell

    2002-01-01

    Improvements in galactic cosmic-ray propagation model parameters are needed to fully exploit high-precision composition data such as that from the ACE and Ulysses spacecraft. Nuclear fragmentation cross section uncertainties have a significant effect on estimates of heavy nuclei spallation in the interstellar medium in certain cases. We have made new measurements of fragmentation cross sections from 56Fe and 60Ni beams

  7. Total photoproduction cross section measurement at HERA energies

    Microsoft Academic Search

    T. Ahmed; V. Andreev; B. Andrieu; M. Arpagaus; A. Babaev; H. Bärwolff; J. Bán; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; G. A. Beck; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; U. Berthon; G. Bertrand-Coremans; M. Besançon; P. Biddulph; E. Binder; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; J. Cvach; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. del Buono; M. Devel; A. de Roeck; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; Y. Feng; I. F. Fensome; J. Ferencei; F. Ferrarotto; W. Flauger; M. Fleischer; P. S. Flower; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; A. Gellrich; M. Gennis; U. Gensch; H. Genzel; R. Gerhards; D. Gillespie; L. Godfrey; U. Goerlach; L. Goerlich; M. Goldberg; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; D. Handschuh; E. M. Hanlon; M. Hapke; J. Harjes; P. Hartz; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; R. Hedgecock; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladký; K. C. Hoeger; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; M. A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; S. Kasarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurça; J. Kurzhöfer; B. Kuznik; R. Lander; M. P. J. Landon; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; A. Leuschner; C. Leverenz; D. Levin; S. Levonian; Ch. Ley; A. Lindner; G. Lindström; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; V. Milone; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; J. M. Morton; K. Müller; P. Murín; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; D. Newton; H. K. Nguyen; F. Niebergall; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; H. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. P. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; R. Prosi; F. Raupach; K. Rauschnabel; P. Reimer; P. Ribarics; V. Riech; J. Riedlberger; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; E. Ryseck; J. Sacton; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; V. Schröder; M. Schulz; A. Schwind; W. Scobel; U. Seehausen; R. Sell; M. Seman; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; L. Smolik; Y. Soloviev; H. Spitzer; P. Staroba; M. Steenbock; P. Steffen; R. Steinberg; H. Steiner; B. Stella; K. Stephens; J. Stier; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; G. Thompson; R. J. Thompson; I. Tichomirov; C. Trenkel; P. Truöl; V. Tchernyshov; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallee; P. van Esch; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegner; H. P. Wellisch; S. Willard; M. Winde; G.-G. Winter; Th. Wolff; L. A. Womersley; A. E. Wright; N. Wulff; T. P. Yiou; J. Áçek; P. Závada; C. Zeitnitz; H. Ziaeepour; M. Zimmer; W. Zimmermann; F. Zomer

    1993-01-01

    We present first results on the total photoproduction cross section measurement with the H1 detector at HERA. The data were extracted from low Q2 collisions of 26.7 GeV electrons with 820 GeV protons. The gammap total cross section has been measured by two independent methods in the gammap center of mass energy range from 90 to 290 GeV. For an

  8. Photoproduction models for total cross section and shower development

    E-print Network

    Fernando Cornet; Carlos Garcia Canal; Agnes Grau; Giulia Pancheri; Sergio Sciutto

    2014-11-19

    A model for the total photoproduction cross section based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  9. Stellar neutron capture cross sections of the Lu isotopes

    Microsoft Academic Search

    K. Wisshak; F. Voss; F. Kaeppeler; L. Kazakov

    2006-01-01

    The neutron capture cross sections of 175Lu and 176Lu have been measured in the energy range 3 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4pi barium fluoride detector. The cross sections

  10. Krypton charge exchange cross sections for Hall effect thruster models

    NASA Astrophysics Data System (ADS)

    Hause, Michael L.; Prince, Benjamin D.; Bemish, Raymond J.

    2013-04-01

    Following discharge from a Hall effect thruster, charge exchange occurs between ions and un-ionized propellant atoms. The low-energy cations produced can disturb operation of onboard instrumentation or the thruster itself. Charge-exchange cross sections for both singly and doubly charged propellant atoms are required to model these interactions. While xenon is the most common propellant currently used in Hall effect thrusters, other propellants are being considered, in particular, krypton. We present here guided-ion beam measurements and comparisons to semiclassical calculations for Kr+ + Kr and Kr2+ + Kr cross sections. The measurements of symmetric Kr+ + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr2+ + Kr reaction, we present cross section measurements for center-of-mass energies between 1 eV and 300 eV, which spans energies not previously examined experimentally. These cross section measurements compare well with a simple one-electron transfer model. Finally, cross sections for the asymmetric Kr2+ + Kr ? Kr+ + Kr+ reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 Å2 with an exception near 70-80 eV.

  11. Studies of 54,56Fe Neutron Scattering Cross Sections

    NASA Astrophysics Data System (ADS)

    Hicks, S. F.; Vanhoy, J. R.; French, A. J.; Henderson, S. L.; Howard, T. J.; Pecha, R. L.; Santonil, Z. C.; Crider, B. P.; Liu, S.; McEllistrem, M. T.; Peters, E. E.; Prados-Estévez, F. M.; Ross, T. J.; Yates, S. W.

    2015-05-01

    Elastic and inelastic neutron scattering differential cross sections and ?-ray production cross sections have been measured on 54,56Fe at several incident energies in the fast neutron region between 1.5 and 4.7 MeV. All measurements were completed at the University of Kentucky Accelerator Laboratory (UKAL) using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and ?-ray detection systems located there. The facilities at UKAL allow the investigation of both elastic and inelastic scattering with nearly mono-energetic incident neutrons. Time-of-flight techniques were used to detect the scattered neutrons for the differential cross section measurements. The measured cross sections are important for fission reactor applications and also for testing global model calculations such as those found at ENDF, since describing both the elastic and inelastic scattering is important for determining the direct and compound components of the scattering mechanism. The ?-ray production cross sections are used to determine cross sections to unresolved levels in the neutron scattering experiments. Results from our measurements and comparisons to model calculations are presented.

  12. Mental visualization of objects from cross-sectional images

    PubMed Central

    Wu, Bing; Klatzky, Roberta L.; Stetten, George D.

    2011-01-01

    We extended the classic anorthoscopic viewing procedure to test a model of visualization of 3D structures from 2D cross-sections. Four experiments were conducted to examine key processes described in the model, localizing cross-sections within a common frame of reference and spatiotemporal integration of cross sections into a hierarchical object representation. Participants used a hand-held device to reveal a hidden object as a sequence of cross-sectional images. The process of localization was manipulated by contrasting two displays, in-situ vs. ex-situ, which differed in whether cross sections were presented at their source locations or displaced to a remote screen. The process of integration was manipulated by varying the structural complexity of target objects and their components. Experiments 1 and 2 demonstrated visualization of 2D and 3D line-segment objects and verified predictions about display and complexity effects. In Experiments 3 and 4, the visualized forms were familiar letters and numbers. Errors and orientation effects showed that displacing cross-sectional images to a remote display (ex-situ viewing) impeded the ability to determine spatial relationships among pattern components, a failure of integration at the object level. PMID:22217386

  13. A genetic algorithm to reduce stream channel cross section data

    USGS Publications Warehouse

    Berenbrock, C.

    2006-01-01

    A genetic algorithm (GA) was used to reduce cross section data for a hypothetical example consisting of 41 data points and for 10 cross sections on the Kootenai River. The number of data points for the Kootenai River cross sections ranged from about 500 to more than 2,500. The GA was applied to reduce the number of data points to a manageable dataset because most models and other software require fewer than 100 data points for management, manipulation, and analysis. Results indicated that the program successfully reduced the data. Fitness values from the genetic algorithm were lower (better) than those in a previous study that used standard procedures of reducing the cross section data. On average, fitnesses were 29 percent lower, and several were about 50 percent lower. Results also showed that cross sections produced by the genetic algorithm were representative of the original section and that near-optimal results could be obtained in a single run, even for large problems. Other data also can be reduced in a method similar to that for cross section data.

  14. THE FREE ANTINEUTRINO ABSORPTION CROSS SECTION. PART I. MEASUREMENT OF THE FREE ANTINEUTRINO ABSORPTION CROSS SECTION. PART II. EXPECTED CROSS SECTION FROM MEASUREMENTS OF FISSION FRAGMENT ELECTRON SPECTRUM

    Microsoft Academic Search

    F. Reines; C. L. Jr. Cowan; R. E. Carter; J. J. Wagner; M. E. Wyman

    1958-01-01

    Part I. The cross section for the reactioa, vâ+ p yields BETA \\/; sup +\\/ + n, was measured using reactor antineutrinos (vâ). Target protons ; were provided by a 370 gallon liquid scintiliation detector in which the ; scintillator solution (triethylbenzene, terphenyl, and POPOP) was loaded with a ; cadmlum compound (cadmium octoate) to allow the detection of the

  15. Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on Ir191

    Microsoft Academic Search

    N. Patronis; C. T. Papadopoulos; S. Galanopoulos; M. Kokkoris; G. Perdikakis; R. Vlastou; A. Lagoyannis; S. Harissopulos

    2007-01-01

    The Ir191(n,2n)Ir190 cross section was measured by means of the activation technique at four neutron energies in the range 10.0 11.3 MeV. The quasimonoenergetic neutron beam was produced via the H2(d,n)He3 reaction at the 5.5 MV Tandem Van de Graaff accelerator of NCSR ``Demokritos.'' The cross section for the population of the second high spin (11-) isomeric state was measured

  16. Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on ¹¹Ir

    Microsoft Academic Search

    N. Patronis; C. T. Papadopoulos; S. Galanopoulos; M. Kokkoris; G. Perdikakis; R. Vlastou; A. Lagoyannis; S. Harissopulos

    2007-01-01

    The ¹¹Ir(n,2n)¹°Ir cross section was measured by means of the activation technique at four neutron energies in the range 10.0-11.3 MeV. The quasimonoenergetic neutron beam was produced via the ²H(d,n)³He reaction at the 5.5 MV Tandem Van de Graaff accelerator of NCSR 'Demokritos'. The cross section for the population of the second high spin (11) isomeric state was measured along

  17. Froissart bound on inelastic cross section without unknown constants

    NASA Astrophysics Data System (ADS)

    Martin, André; Roy, S. M.

    2015-04-01

    Assuming that axiomatic local field theory results hold for hadron scattering, André Martin and S. M. Roy recently obtained absolute bounds on the D wave below threshold for pion-pion scattering and thereby determined the scale of the logarithm in the Froissart bound on total cross sections in terms of pion mass only. Previously, Martin proved a rigorous upper bound on the inelastic cross-section ?inel which is one-fourth of the corresponding upper bound on ?tot, and Wu, Martin, Roy and Singh improved the bound by adding the constraint of a given ?tot. Here we use unitarity and analyticity to determine, without any high-energy approximation, upper bounds on energy-averaged inelastic cross sections in terms of low-energy data in the crossed channel. These are Froissart-type bounds without any unknown coefficient or unknown scale factors and can be tested experimentally. Alternatively, their asymptotic forms, together with the Martin-Roy absolute bounds on pion-pion D waves below threshold, yield absolute bounds on energy-averaged inelastic cross sections. For example, for ?0?0 scattering, defining ?inel=?tot-(??0?0??0?0+??0?0??+?-) , we show that for c.m. energy ?{s }??, ?¯ inel(s ,?)?s ?s?d s'?inel(s')/s'2?(? /4 )(m?)-2[ln (s /s1)+(1 /2 )ln ln (s /s1)+1 ]2 where 1 /s1=34 ? ?{2 ? }m?-2 . This bound is asymptotically one-fourth of the corresponding Martin-Roy bound on the total cross section, and the scale factor s1 is one-fourth of the scale factor in the total cross section bound. The average over the interval (s,2s) of the inelastic ?0?0 cross section has a bound of the same form with 1 /s1 replaced by 1 /s2=2 /s1.

  18. Absolute cross sections for electron scattering from furan.

    PubMed

    Maljkovi?, J B; Blanco, F; ?urík, R; García, G; Marinkovi?, B P; Milosavljevi?, A R

    2012-08-14

    We report results of measurements and calculations of absolute cross sections for electron scattering from furan molecules (C(4)H(4)O). The experimental absolute differential cross sections (DCSs) for elastic electron scattering were obtained for the incident energies from 50 eV to 300 eV and for scattering angles from 20° to 110°, by using a crossed electron-target beam setup and the relative flow technique for calibration to the absolute scale. The calculations of the electron interaction cross sections are based on a corrected form of the independent-atom method, known as the screening corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. The latter calculations also account for rotational excitations in the approximation of a free electric dipole and were used to obtain elastic DCSs as well as total and integral elastic cross sections which are tabulated in the energy range from 10 to 10 000 eV. All SCAR calculated cross sections agree very well with both the present and previously published experimental results. Additionally, calculations based on the first Born approximation were performed to calculate both elastic and vibrationally inelastic DCSs for all the modes of furane, in the energy range from 50 eV to 300 eV. The ratios of the summed vibrational to elastic DCSs are presented and discussed. Finally, the present results for furan are compared with previously published elastic DCSs for the tetrahydrofuran molecule and discussed. PMID:22897278

  19. Accuracy of respiratory inductive plethysmographic cross-sectional areas.

    PubMed

    Watson, H L; Poole, D A; Sackner, M A

    1988-07-01

    The present study was undertaken to evaluate whether the respiratory inductive plethysmograph (RIP) 1) reflects changes of cross-sectional area enclosed by its transducer band in the presence of deformations of shape or whether it 2) has a stable base line. Testing of RIP was carried out with a device incorporating a thermally compensated oscillator and digital demodulatory circuitry. This system, introduced to commerce in 1983, superceded the nonthermal compensated oscillatory and analog demodulator circuitry first used in 1977. Testing the effects of changing cross-sectional area was accomplished by stretching a standard RIP transducer band around wooden dowels placed in holes on a peg board grid to form 23 curved and 5 rectangular shapes. The output voltage from RIP was linear for both the curved and rectangular shapes for changes of cross-sectional area within a physiological range. However, the regression line of voltage vs. cross-sectional area for the rectangular shapes was parallel and slightly displaced from the regression line for the curved shapes due to mutual coupling of inductance in the corners. Base-line drift from a RIP transducer band stretched to enclose an elliptical shape was less than 2.5 mV over a 12-h observation period. Current RIP technology accurately reflects changes of cross-sectional area of physiological shapes and has a stable base line. PMID:3403473

  20. Mg in electromagnetic fields: Theoretical partial multiphoton cross sections

    SciTech Connect

    Nikolopoulos, L.A.A. [Department of Telecommunications Science and Technology, University of Peloponnese, 22 100 Tripolis (Greece)

    2005-03-01

    We present ab initio calculations of multiphoton ionization cross sections--up to four--in atomic magnesium. We have followed a configuration interaction approach with the basis set constructed in terms of L{sup 2} integrable B-spline polynomials. The multiphoton ionization cross sections are given for a range of photon energies where the ion is left in its ground state. For the two-photon ionization process we calculate the cross section as a function of the photon energy and compare with known theoretical results. We also provide the corresponding angular asymmetry parameters which determine the angular distribution of the ionized electron. We have extended the energy range of reported theoretical three-photon ionization cross section while we present the four-photon cross section in the region between the 3s and 3p ionization thresholds. In this region the 3p{sup 2} {sup 1}S autoionizing state is identified through the four-photon absorption process and the related four-photon Fano q parameter is obtained.

  1. Electromagnetic Dissociation Cross Sections using Weisskopf-Ewing Theory

    NASA Technical Reports Server (NTRS)

    Adamczyk, Anne M.; Norbury, John W.

    2011-01-01

    It is important that accurate estimates of crew exposure to radiation are obtained for future long-term space missions. Presently, several space radiation transport codes exist to predict the radiation environment, all of which take as input particle interaction cross sections that describe the nuclear interactions between the particles and the shielding material. The space radiation transport code HZETRN uses the nuclear fragmentation model NUCFRG2 to calculate Electromagnetic Dissociation (EMD) cross sections. Currently, NUCFRG2 employs energy independent branching ratios to calculate these cross sections. Using Weisskopf-Ewing (WE) theory to calculate branching ratios, however, is more advantageous than the method currently employed in NUCFRG2. The WE theory can calculate not only neutron and proton emission, as in the energy independent branching ratio formalism used in NUCFRG2, but also deuteron, triton, helion, and alpha particle emission. These particles can contribute significantly to total exposure estimates. In this work, photonuclear cross sections are calculated using WE theory and the energy independent branching ratios used in NUCFRG2 and then compared to experimental data. It is found that the WE theory gives comparable, but mainly better agreement with data than the energy independent branching ratio. Furthermore, EMD cross sections for single neutron, proton, and alpha particle removal are calculated using WE theory and an energy independent branching ratio used in NUCFRG2 and compared to experimental data.

  2. Single-top Cross Section Measurements at ATLAS

    E-print Network

    P. Ryan

    2008-11-28

    The single-top production cross section is one third that of the top-pair production cross section at the LHC. During a year of data-taking, assuming an average luminosity of 10^33 cm-2 s-1 and a CMS energy of 14 TeV, the determination of the major contributions to the total single-top cross section should be achievable. Comparisons between the measured cross sections and the theoretical predictions will provide a crucial test of the standard model. These measurements should also lead to the first direct measurement of |V_tb|, with a precision at the level of a few percent. In addition, they will probe for new physics via the search for evidence of anomalous couplings to the top quark and the measurements of additional bosonic contributions to single-top production. Methods developed to optimize the selection of single-top events in the three production channels are presented and the potential for the cross section measurements with 1 fb-1 and 30 fb-1 of integrated luminosity is established.

  3. Analysis of Ku-band cross section at low incidence angles

    NASA Astrophysics Data System (ADS)

    Chapron, B.; Vandemark, D.

    This study is using airborne Ku-band data to address questions which have implications for both model function development and for advancing our physical understanding of the sea surface. Concurrent measurements of ocean directional spectra, significant wave height, and mean surface roughness are made using the capabilities of the radar ocean wave spectrometer (ROWS). The NASA/GSFC's ROWS is a 15 GHz pulse compressed radar which is a radar sensor designed to measure the direction of the long wave components using spectral analysis of the tilt induced reflectively modulation. The ROWS are modified to cycle at 50 Hz for the scanning spectrometer antenna and a wide beamwidth nadir altimeter mode. This change allows the sensor to simultaneously measure directional wave spectra, wave height, mean square slope parameter, and small scale surface roughness. The surface stress caused by the wind is widely believed to be the predominant quantity related to the Ku-band radar cross section for a wide range of incidence angles. The complete coverage in the quasi specular region provided by one sensor is essential to understand the uncertainties between the scattering model and what is happening on the surface. For this presentation, special attention is devoted to sort out some measurement of the anisotropy associated with the band of high frequencies. Using the other geophysical parameters, comparisons are then made with the classic spectral form currentlyused to describe the wind impact on the sea surface.

  4. ESTIMATING HYDROGEOLOGIC PARAMETERS FROM RADAR DATA

    Microsoft Academic Search

    Charles T. Young

    Radar reflections for a layered medium are dependant on the dielectric constants of the layers, which is closely linked to saturated porosity, and more loosely to hydraulic conductivity. Radar data have been obtained at a site where hydraulic conductivity has been measured in great detail. The radar cross section from the site clearly shows layering within the section, and it

  5. Neutron Capture Cross Section Calculations with the Statistical Model

    NASA Astrophysics Data System (ADS)

    Beard, Mary; Uberseder, Ethan; Wiescher, Michael

    2014-09-01

    Hauser-Feshbach (HF) cross sections are of enormous importance for a wide range of applications, from waste transmutation and nuclear technologies, to medical applications, and nuclear astrophysics. It is a well observed result that different nuclear input models sensitively affect HF cross section calculations. Less well-known however are the effects on calculations originating from model-specific implementation details (such as level density parameter, matching energy, backshift and giant dipole parameters), as well as effects from non-model aspects, such as experimental data truncation and transmission function energy binning. To investigate the effects or these various aspects, Maxwellian-averaged neutron capture cross sections have been calculated for approximately 340 nuclei. The relative effects of these model details will be discussed.

  6. pi+- p differential cross sections at low energies

    E-print Network

    H. Denz; P. Amaudruz; J. T. Brack; J. Breitschopf; P. Camerini; J. L. Clark; H. Clement; L. Felawka; E. Fragiacomo; E. F. Gibson; N. Grion; G. J. Hofman; B. Jamieson; E. L. Mathie; R. Meier; G. Moloney; D. Ottewell; O. Patarakin; J. D. Patterson; M. M. Pavan; S. Piano; K. Raywood; R. A. Ristinen; R. Rui; M. E. Sevior; G. R. Smith; J. Stahov; R. Tacik; G. J. Wagner; F. von Wrochem; D. M. Yeomans

    2005-12-03

    Differential cross sections for pi- p and pi+ p elastic scattering were measured at five energies between 19.9 and 43.3 MeV. The use of the CHAOS magnetic spectrometer at TRIUMF, supplemented by a range telescope for muon background suppression, provided simultaneous coverage of a large part of the full angular range, thus allowing very precise relative cross section measurements. The absolute normalisation was determined with a typical accuracy of 5 %. This was verified in a simultaneous measurement of muon proton elastic scattering. The measured cross sections show some deviations from phase shift analysis predictions, in particular at large angles and low energies. From the new data we determine the real part of the isospin forward scattering amplitude.

  7. Lanl Neutron-Induced Fission Cross Section Measurement Program

    NASA Astrophysics Data System (ADS)

    Laptev, A. B.; Tovesson, F.; Hill, T. S.

    2014-09-01

    A well established program of neutron-induced fission cross section measurement at Los Alamos Neutron Science Center (LANSCE) is supporting the Fuel Cycle Research program (FC R&D). Combining measurements at two LANSCE facilities, the Lujan Center and the Weapons Neutron Research facility (WNR), cover neutron energies over 10 orders of magnitude: from sub-thermal up to 200 MeV. A parallel-plate fission ionization chamber was used as a fission fragment detector. The 235U(n,f) standard was used as the reference. Fission cross sections have been measured for multiple actinides. The new data presented here completes the suite of long-lived Uranium isotopes that were investigated with this experimental approach. The cross section data are presented in comparison with existing evaluations and previous measurements.

  8. Parameterized total cross sections for pion production in nuclear collisions

    E-print Network

    John W. Norbury; Lawrence W. Townsend

    2006-12-18

    Total inclusive cross sections for neutral and charged pion production in proton-nucleus and nucleus-nucleus reactions have been calculated and compared to experiment. Nucleon-nucleon theoretical cross sections have been scaled up to nuclear collisions using a scaling factor similar to $(A_PA_T)^{2/3}$, where $A_P$ and $A_T$ are the nucleon numbers of the projectile and target nuclei. Variations in the power of this scaling factor have been studied and a good fit to experiment is obtained with a small modification of the power. Theoretical cross sections are written in a form that is very suitable for immediate input into transport codes.

  9. Pion Total Cross Section in Nucleon - Nucleon Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    2009-01-01

    Total cross section parameterizations for neutral and charged pion production in nucleon - nucleon collisions are compared to experimental data over the projectile momentum range from threshold to 300 GeV. Both proton - proton and proton - neutron reactions are considered. Overall excellent agreement between parameterizations and experiment is found, except for notable disagreements near threshold. In addition, the hypothesis that the neutral pion production cross section can be obtained from the average charged pion cross section is checked. The theoretical formulas presented in the paper obey this hypothesis for projectile momenta below 500 GeV. The results presented provide a test of engineering tools used to calculate the pion component of space radiation.

  10. Light stops emerging in WW cross section measurements?

    E-print Network

    Krzysztof Rolbiecki; Kazuki Sakurai

    2013-08-12

    Recent ATLAS and CMS measurements show a slight excess in the WW cross section measurement. While still consistent with the Standard Model within 1-2 sigma, the excess could be also a first hint of physics beyond the Standard Model. We argue that this effect could be attributed to the production of scalar top quarks within supersymmetric models. The stops of mstop_1 ~ 200 GeV has the right pair-production cross section and under some assumptions can significantly contribute to the final state of two leptons and missing energy. We scan this region of parameter space to identify stop mass range preferred by the WW cross section measurements. Taking one sample benchmark point we show that it can be consistent with low energy observables and Higgs sector measurements and propose a method to distinguish supersymmetric signal from the Standard Model contribution.

  11. Large cross sections for transitions with a small energy difference

    NASA Astrophysics Data System (ADS)

    McGuire, J. H.; Shakov, Kh. Kh.

    2009-05-01

    Cross sections for transitions between states with small differences in energy can be quite large. An example is the 1s-2p transition in atomic hydrogen caused by the impact of a fast charged particle [1] or a photon [3]. In such cases the actual cross section may become much larger than the simple geometric cross section. Such transitions are often difficult to observe in the laboratory. However, they can be evaluated numerically. This effect can be significant in analysis of astrophysical data, as pointed out by T. Nandi [2]. I discuss a few examples of calculations and give a physical explanation for this effect. [4pt] [1] J.H. McGuire, D. J. Land, J. G. Brennan and G. Basbas, Phys. Rev. A19, 2180 (1979).[0pt] [2] Kh.Kh. Shakov and J.H. McGuire, Phys. Rev. A67 033405 (2003). [0pt] [3] T. Nandi, private communication, 2008.

  12. pi+- p differential cross sections at low energies

    SciTech Connect

    H. Denz; P. Amaudruz; J.T. Brack; J. Breitschopf; P. Camerini; J.L. Clark; H. Clement; L. Felawka; E. Fragiacomo; E.F. Gibson; N. Grion; G.J. Hofman; B. Jamieson; E.L. Mathie; R. Meier; G. Moloney; D. Ottewell; O. Patarakin; J.D. Patterson; M.M. Pavan; S. Piano; K. Raywood; R.A. Ristinen; R. Rui; M.E. Sevior; G.R. Smith; J. Stahov; R. Tacik; G.J. Wagner; F. von Wrochem; D.M. Yeomans

    2005-12-03

    Differential cross sections for pi- p and pi+ p elastic scattering were measured at five energies between 19.9 and 43.3 MeV. The use of the CHAOS magnetic spectrometer at TRIUMF, supplemented by a range telescope for muon background suppression, provided simultaneous coverage of a large part of the full angular range, thus allowing very precise relative cross section measurements. The absolute normalization was determined with a typical accuracy of 5 %. This was verified in a simultaneous measurement of muon proton elastic scattering. The measured cross sections show some deviations from phase shift analysis predictions, in particular at large angles and low energies. From the new data we determine the real part of the isospin forward scattering amplitude.

  13. ABSOLUTE PHOTODETACHMENT CROSS-SECTION MEASUREMENTS FOR HYDROCARBON CHAIN ANIONS

    SciTech Connect

    Best, T.; Otto, R.; Wester, R. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Trippel, S.; Hlavenka, P.; Von Zastrow, A.; Eisenbach, S.; Jezouin, S. [Physikalisches Institut, Universitaet Freiburg, 79104 Freiburg (Germany); Vigren, E.; Hamberg, M.; Geppert, W. D., E-mail: roland.wester@uibk.ac.at [Molecular Physics Division, Stockholm University, Stockholm (Sweden)

    2011-12-01

    Absolute photodetachment cross sections have been measured for the hydrocarbon chain anions C{sub n}H{sup -}, n = 2, 4, and 6, which are relevant for an understanding of molecular clouds in the interstellar medium. Data have been obtained for different photon energies within approximately 1 eV of the detachment threshold. With our recently developed method we have achieved a precision of better than 25% on these absolute cross sections. The experiments have been carried out by means of photodetachment tomography of the mass-selected molecular anions in a multipole radio-frequency ion trap. The measured absolute cross sections are in accordance with the empirical scaling law of Millar et al. and have allowed us to determine its free parameters. These results are important for predicting the photostability and thus the abundance of carbon chain anions in planetary atmospheres, in circumstellar envelopes, and in photon-dominated regions of interstellar molecular clouds.

  14. Dosimetry and cross section measurements at RTNS II

    SciTech Connect

    Greenwood, L.R.; Kneff, D.W.

    1987-01-01

    Numerous measurements have been conducted at TRNS-II in order to map the neutron field for materials irradiations, to measure activation cross sections, and to measure helium production cross sections. Experiments of up to two weeks duration irradiated large numbers of activation dosimetry and helium samples both close to the source and throughout the target room. Many other samples have been irradiated in piggy-back positions over periods lasting many months. All of these experiments fall into four main classes, namely, fluence-mapping, activation dosimetry, the production of long-lived isotopes, and helium generation measurements. Radiometric dosimetry and activation cross section measurements were performed at Argonne National Laboratory; helium production was measured at Rockwell International Corporation. This paper briefly summarizes the principal results of our measurements at RTNS-II; references are given for more detailed publications. 14 refs., 4 figs.

  15. Recent advances in modeling fission cross sections over intermediate structures

    SciTech Connect

    Bouland, Olivier [Los Alamos National Laboratory; Lynn, J. Eric [Los Alamos National Laboratory; Talou, Patrick [Los Alamos National Laboratory

    2009-01-01

    More accurate fission cross section calculations in presence of underlying intermediate structure are strongly desired. This paper recalls the common approximations used below the fission threshold and quantifies their impact. In particular, an exact expanded R-matrix Monte Carlo calculation of the intermediate structure, deeply mixed with the fluctuations of the class-I and II decay amplitudes, is shown. This paper also insists on the microscopic structure of the level densities as a function of the nucleus deformation and show preliminary neutron induced fission cross section calculations for {sup 239}Pu and {sup 240}Pu using newly calculated combinatorial level densities. Comparisons with recent evaluated and measured fission cross sections are made.

  16. Predicting differential cross sections of electron scattering from polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Sun, Weiguo; Wang, Qi; Zhang, Yi; Li, Huidong; Feng, Hao; Fan, Qunchao

    2015-06-01

    Based on a difference converging method (DCM) and the general differential cross section (DCS) expression, an analytical formula and a converging protocol used to predict accurate values of experimentally unknown DCSs are proposed. The accurate DCSs, integral cross sections and momentum transfer cross sections of electron scattering from {{N}2}, {{H}2}O, C{{H}4}, and C{{F}3}I molecules are studied using the new formula and a set of experimental DCSs. The calculated results show that not only all known experimental DCSs are excellently reproduced but also the unknown ones are correctly predicted. This study suggests a method as a reliable and economical theoretical alternative to obtain unknown DCSs of electron scattering from a polyatomic molecule.

  17. Realistic Calculations for Neutrino-Nucleus Reactions Cross sections

    SciTech Connect

    Chasioti, V. C.; Kosmas, T. S.; Divari, P. C. [Theoretical Physics Section, University of Ioannina, GR 45110 Ioannina (Greece)

    2008-01-24

    Inelastic neutrino-nucleus reaction cross sections at low and intermediate neutrino energies are studied. The required many-body nuclear wave-functions are calculated by utilizing a version of the quasi-particle random phase approximation (QRPA) that uses realistic two-body forces. The results presented here refer to the differential, integrated and total cross sections of the neutral-current induced reaction of {nu}{sub e} with the {sup 98}Mo and {sup 40}Ar nuclei. These isotopes are considered as promising astrophysical neutrino detection targets in recent neutrino physics research.

  18. Differential cross sections for neutrino scattering on {sup 12}C

    SciTech Connect

    Kolbe, E. [Departement fuer Physik und Astronomie der Universitaet Basel (Switzerland)] [Departement fuer Physik und Astronomie der Universitaet Basel (Switzerland)

    1996-10-01

    Differential cross sections for neutrino scattering on {sup 12}C are calculated within the (continuum) random phase approximation model. The charged current ({nu}{sub {ital e}},{ital e}{sup {minus}}) and ({nu}{sub {mu}},{mu}{sup {minus}}) capture reactions on {sup 12}C are measured by the LSND Collaboration at LAMPF. We investigate and discuss the merits of such studies, especially the information that can be extracted from data for differential neutrino scattering cross sections. {copyright} {ital 1996 The American Physical Society.}

  19. Photon gluon fusion cross sections at HERA energy

    NASA Astrophysics Data System (ADS)

    Engelen, J. J.; Dejong, S. J.; Poletiek, M.; Vermaseren, J. A. M.

    1988-01-01

    Cross sections for heavy flavor production through photon gluon fusion in electron proton collisions are presented. The electron photon vertex is taken into account explicitly, and the Q sq of the exchanged photon ranges from nearly zero (almost real photon) to the kinematically allowed maximum. The QCD scale is set by the mass of the produced quarks. The formalism is also applicable to the production of light quarks as long as the invariant mass of the pair is sufficiently high, so cross sections for u anti-u, d anti-d, and s anti-s production are also given.

  20. Total photoproduction cross-section at very high energy

    E-print Network

    Godbole, R M; Pancheri, G; Srivastava, Y N

    2008-01-01

    In this paper we apply to photoproduction total cross-section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. When we extend the model to cosmic ray energies, our model predicts substantially higher cross-sections at TeV energies than models based on factorization but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference and comment on the Froissart bound for photon induced processes.

  1. Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.

    2014-09-01

    The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. Supported by U.S. DOE, Contract No. DE-AC02-06CH11357.

  2. Controlling inclusive cross sections in parton shower + matrix element merging

    E-print Network

    Simon Platzer

    2012-12-03

    We propose an extension of matrix element plus parton shower merging at tree level to preserve inclusive cross sections obtained from the merged and showered sample. Implementing this constraint generates approximate next-to-leading order (NLO) contributions similar to the LoopSim approach. We then show how full NLO, or in principle even higher order, corrections can be added consistently, including constraints on inclusive cross sections to account for yet missing parton shower accuracy at higher logarithmic order. We also show how NLO accuracy below the merging scale can be obtained.

  3. Inelastic cross sections from gamma-ray measurements

    SciTech Connect

    Nelson, Ronald Owen [Los Alamos National Laboratory

    2010-12-06

    Measurements of gamma rays following neutron induced reactions have been studied with the Germanium Array for Neutron-induced Excitations (GEANIE) at the Los Alamos Neutron Science Center (LANSCE) for many years. Gamma-ray excitation functions and coincidence studies provide insight into nuclear reaction mechanisms as well as expanding our knowledge of energy levels and gamma-rays. Samples studied with Ge detectors at LANSCE range from Be to Pu. Fe, Cr and Ti have been considered for use as reference cross sections. An overview of the measurements and efforts to create a reliable neutron-induced gamma-ray reference cross section will be presented.

  4. Experimental helium generation cross sections for fast neutrons

    NASA Astrophysics Data System (ADS)

    Kneff, D. W.; Oliver, B. M.; Nakata, M. M.; Farrar, Harry

    Total helium generation cross sections of Al, V, Fe, Ni, Cu, Zr, Mo, Au, and the separated isotopes of Fe, Ni, Cu, and Mo have been measured for ˜14.8-MeV T(d,n) neutrons and for a ˜0-32 MeV Be(d,n) neutron field. The results, obtained using high-sensitivity gas mass spectrometry, are presented in this paper along with a summary of our previous T(d,n) helium generation cross section measurements.

  5. Measurements of multiphoton action cross sections for multiphoton microscopy.

    PubMed

    Cheng, Li-Chung; Horton, Nicholas G; Wang, Ke; Chen, Shean-Jen; Xu, Chris

    2014-10-01

    We report quantitative measurements of two-, three-, and four-photon excitation action cross sections of several commonly used fluorophores and fluorescent proteins at three different excitation wavelengths of 800 nm, 1300 nm, and 1680 nm. The measured cross section values are consistent with simple quantum mechanic estimations. These values indicate that the optimum repetition rate for deep tissue 3-photon microscopy is approximately 1 to 2 MHz. We further demonstrate that it is feasible to perform 4-photon fluorescence microscopy of GFP labeled microglia in mouse brain in vivo at 1700 nm. 4-photon excitation increases the accessibility of fluorophores at the long wavelength spectral window of 1700 nm. PMID:25360361

  6. International evaluation cooperation Subgroup 7: Multigroup cross section processing

    SciTech Connect

    Roussin, R.W.; White, J.E. (Oak Ridge National Lab., TN (USA)); Sartori, E. (NEA Data Bank, 91 - Gif-sur-Yvette (France)); Panini, G. (ENEA, Bologna (Italy)); MacFarlane, R. (Los Alamos National Lab., NM (USA)); Muir, D. (International Atomic Energy Agency, Vienna (Austria). Nuclear Data Section); Mattes, M. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Kernenergetik und Energiesysteme); Hasegawa, I

    1991-01-01

    The chairmen of the ENDF/B, JEF, EFF, and JENDL evaluated data files adopted a proposal to develop a fine-group processed cross section library based on the VITAMIN'' concept. The authors listed above, with support from others, are participating in this project. The end result will be a pseudo-problem-independent fine-group cross section library generated from the latest evaluated data in ENDF/B-VI, JEF-2, EFF-2, and JENDL-3. Initial applications of the library will be for shielding, fast reactor physics, and fusion neutronics. Progress made to date will be discussed. 8 refs.

  7. Evaluation of the /sup 238/U neutron total cross section

    SciTech Connect

    Smith, A.; Poenitz, W.P.; Howerton, R.J.

    1982-12-01

    Experimental energy-averaged neutron total cross sections of /sup 238/U were evaluated from 0.044 to 20.0 MeV using regorous numerical methods. The evaluated results are presented together with the associated uncertainties and correlation matrix. They indicate that this energy-averaged neutron total cross section is known to better than 1% over wide energy regions. There are somwewhat larger uncertainties at low energies (e.g., less than or equal to 0.2 MeV), near 8 MeV and above 15 MeV. The present evaluation is compard with values given in ENDF/B-V.

  8. Neutron removal cross section as a measure of neutron skin

    SciTech Connect

    Fang, D. Q.; Ma, Y. G.; Cai, X. Z.; Tian, W. D.; Wang, H. W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Post Office Box 800-204, Shanghai 201800 (China)

    2010-04-15

    We study the relation between neutron removal cross section (sigma{sub -N}) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between sigma{sub -N} and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

  9. A radar-echo model for Mars

    NASA Technical Reports Server (NTRS)

    Thompson, T. W.; Moore, H. J.

    1990-01-01

    Researchers developed a radar-echo model for Mars based on 12.6 cm continuous wave radio transmissions backscattered from the planet. The model broadly matches the variations in depolarized and polarized total radar cross sections with longitude observed by Goldstone in 1986 along 7 degrees S. and yields echo spectra that are generally similiar to the observed spectra. Radar map units in the model include an extensive cratered uplands unit with weak depolarized echo cross sections, average thermal inertias, moderate normal refelectivities, and moderate rms slopes; the volcanic units of Tharsis, Elysium, and Amazonis regions with strong depolarized echo cross sections, low thermal inertia, low normal reflectivities, and large rms slopes; and the northern planes units with moderate to strong depolarized echo cross sections, moderate to very high thermal inertias, moderate to large normal reflectivities, and moderate rms slopes. The relevance of the model to the interpretation of radar echoes from Mars is discussed.

  10. Permafrost Ice Wedge Geometry Estimates from Ground Penetrating Radar Profiling

    NASA Astrophysics Data System (ADS)

    Parsekian, A.; Jafarov, E. E.; Schaefer, K. M.

    2014-12-01

    Permafrost ice wedges are found throughout terrestrial cryosphere, often comprising the dominant fraction of ground ice. This form of ground has important implications in a permafrost system because as the wedge ice, the inherent structural support given to the sediment is lost and subsidence and flooding occurs. The volume of ice found in wedges is poorly known because the wedge geometry is difficult to measure with direct methods; most estimates of wedge depth come from exposures at thermo-erosional features. Here we demonstrate the a novel interpretation of a well-known non-invasive ground penetrating radar (GPR) measurement that may be useful for measuring ice wedge depth. Using synthetic data and a field data examples, we detail the signal anomaly observed in the GPR record associated with ice wedges and demonstrate that a genetic algorithm (GA) inversion can be used to recover the wedge depth by optimizing the fit between measured and simulated radar cross section (RCS). Our results indicate that this optimization approach can recover wedge geometry even under noisy conditions.

  11. Active radar stealth device

    NASA Astrophysics Data System (ADS)

    Cain, R. N.; Corda, Albert J.

    1991-07-01

    This patent discloses an active radar stealth device mounted on a host platform for minimizing the radar cross-section of the host platform. A coating which is essentially microwave transparent is attached to the surface of a host platform and is exposed to an incident microwave field. A plurality of detector/emitter pairs contained within the coating detect and actively cancel, respectively, the microwave field at each respective detector/emitter pair.

  12. Soda Lake Well Lithology Data and Geologic Cross-Sections

    SciTech Connect

    Faulds, James E.

    2013-12-31

    Comprehensive catalogue of drill?hole data in spreadsheet, shapefile, and Geosoft database formats. Includes XYZ locations of well heads, year drilled, type of well, operator, total depths, well path data (deviations), lithology logs, and temperature data. Plus, 13 cross?sections in Adobe Illustrator format.

  13. Soda Lake Well Lithology Data and Geologic Cross-Sections

    DOE Data Explorer

    Faulds, James E.

    Comprehensive catalogue of drill?hole data in spreadsheet, shapefile, and Geosoft database formats. Includes XYZ locations of well heads, year drilled, type of well, operator, total depths, well path data (deviations), lithology logs, and temperature data. Plus, 13 cross?sections in Adobe Illustrator format.

  14. Measurements of four-fermion cross-sections at LEP

    NASA Astrophysics Data System (ADS)

    Kopal, Miroslav

    The production of four fermions in e+e- collisions at LEP allows the verification of the Standard Model of the Electroweak Interactions in the Charged and Neutral Current Sectors. Among the four-fermion final states, the highest purity and the clearest four-fermion events are characterized by the presence of leptons in the final state. The identification of such final states in the full data sample collected by the L3 experiment at LEP in the years from 1997 through 2000 is described. The total amount of data analyzed in this thesis corresponds to the total integrated luminosity 675.5 pb-1. This thesis presents the results of the selection of the Z boson pair production together with the measurement of the cross-section for leptonic four-fermion final states, and the first measurement of cross-sections in the four-lepton and two-lepton and missing energy channels of the Zg* production with the L3 detector. The cross-section average over the whole data sample was found to be: s(e+e-?Zg *?l+l-l' +l'-) =0.087+0.030-0.026pb, s(e+e-?Zg *?l+l-n n¯) =0.062+0.032-0.027p b. This thesis also presents the results of the selection of the single W production and the cross-section measurements of the semileptonic decays of the W boson. All measurements are consistent with the Standard Model expectations.

  15. C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Almaraz-Calderon, S.; Carnelli, P. F. F.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Digiovine, B.; Esbensen, H.; Fernandez Niello, J. O.; Henderson, D.; Jiang, C. L.; Lai, J.; Marley, S. T.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Paul, M.; Ugalde, C.

    2015-06-01

    Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work.

  16. Applications of cross sections for electron-molecule collision processes

    SciTech Connect

    Cartwright, D.C.

    1985-01-01

    The role of electron-molecule collision cross sections is discussed for the study of the ionospheric and auroral processes in planetary atmospheres and of discharge-pumped lasers. These two areas emphasize the importance of further theoretical and experimental studies concerning electron-impact processes. 13 refs., 3 figs., 2 tabs. (WRF)

  17. Absolute measurements of photoionization cross-sections for ions

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Henrik; Folkmann, Finn; van Elp, Jan; Knudsen, Helge; West, John B.; Andersen, Torkild

    2005-06-01

    A merged-beam set-up for absolute measurements of photoionization cross-sections of ions is described. The facility is capable of recording cross-sections as low as 10 -19 cm 2 and has been used to study a large number of singly- and multiply-charged, atomic and molecular, positive and negative ions. It is based on a synchrotron radiation beam line fitted with an undulator at the storage ring ASTRID and a low-energy (˜2 keV) ion beam line. Photons in the energy range 15-200 eV are merged co-linearly with the target ions over a distance of 50 cm, and the absolute photoionization cross-section is determined from the resulting photoion yield with a typical accuracy of 10%. Different types of ion sources are available, thus permitting a large number of positive and negative, atomic and molecular, singly- and multiply-charged ions to be investigated. Emphasis is put on accurate determination of the absolute cross-sections, requiring calibration of photodiode and particle detectors together with measurements of the photon-ion overlap.

  18. SCATTERING AND CONVERSION CROSS SECTIONS IN INHOMOGENEOUS PLASMA

    Microsoft Academic Search

    Marshall H. Cohen

    1962-01-01

    A general scattering theory is developed for a magneticfield-free ; plasma, allowing for both transverse and longitudinal waves. Cross sections are ; derived, which give the scattered components in terms of the frequencies of the ; incident and scattered waves, and the intensities of the appropriate components ; in the spectrum of density variations. The theory includes several other ;

  19. The radiation damage database: Section on helium cross section

    NASA Astrophysics Data System (ADS)

    Lu, W.; Wechsler, M. S.

    2007-04-01

    A radiation damage database with emphasis on spallation interactions is described. Currently, the database contains damage energy, displacement, helium, and hydrogen cross sections for 23 elemental targets irradiated by proton and neutron projectiles up to 3.2 GeV. In this paper, the focus is on proton-induced helium cross sections, but it is shown that for high energies (above about 500 MeV) proton- and neutron-induced helium cross sections are almost equal. The cross section calculations were run on the Cascade-Exciton Model code (no options) and also on the Bertini code with three nuclear level-density models and multistage pre-equilibrium model on and off. Calculation and experimental results are compared. For various targets, we tried to determine which code and options give best agreement with experiment. In some cases, such determinations are uncertain, partly because of limited and conflicting experimental information and partly perhaps because of the need for modifications in the codes.

  20. Neutron activation cross-section of zirconium-94

    Microsoft Academic Search

    1978-01-01

    The thermal neutron activation cross-section of94Zr was found to be 49.3±0.6 millibarns. It is shown that neutron activation analysis of Zr in silicate samples with a Zr\\/U\\u000a ratio<10 has considerable uncertainty due to fission contribution. A correction factor for the fission contribution has been\\u000a determined experimentally.

  1. Determination of absolute photoionization cross sections of the phenyl radical

    E-print Network

    Neumark, Daniel M.

    Determination of absolute photoionization cross sections of the phenyl radical Niels E. Sveum sections of the phenyl radical to form the phenyl cation were measured using tunable vacuum ultraviolet synchrotron radiation coupled with photofragment translational spectroscopy. The phenyl radical was produced

  2. Skin Diseases: Cross-section of human skin

    MedlinePLUS

    Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Cross-section of human skin Past Issues / Fall 2008 Table of Contents For ... I n the areas of skin health and skin diseases, the NIH's National Institute of Arthritis and Musculoskeletal ...

  3. Electron-Impact Total Ionization Cross Section of Rb.

    NASA Astrophysics Data System (ADS)

    Kim, Y.-K.; Migdalek, J.; Siegel, W.; Biero?, J.

    1997-04-01

    The Binary-Encounter-Dipole (BED) model(Y.-K. Kim and M.E. Rudd, Phys. Rev. A 50), 3954 (1994). has been applied to electron-impact ionization of Rb. The BED cross section is in good agreement with a recent experimental data.(R.S. Schappe et al., Phys. Rev. Lett. 76), 4328 (1996). The BED theory combines a modified Mott cross section with the high-incident energy behavior of the Born cross section. The required continuum f-values were calculated from Dirac-Fock continuum wave functions with a core polarization potential.(J. Migdalek and W.E. Baylis, J. Phys. B 11), L497 (1978). The cut-off radius of the matching dipole transition operator was adjusted to reproduce the position of the known minimum in the photoionization cross section.(H. Suemitsu and J.A.R. Samson, Phys. Rev. 28), 2752 (1983). The contributions of the 4p arrow 4d, 5s, and 5p autoionizing excitations were included using the plane-wave Born approximation. We also present f-values for the 5s arrow np_1/2, np_3/2 transitions for high n near the ionization threshold.

  4. NINE AND SIXTEEN GROUP CROSS SECTIONS FOR REACTOR ANALYSIS

    Microsoft Academic Search

    C. S. Robertson; E. M. Benson

    1963-01-01

    Nine and sixteen group cross sections for use in transport theory codes ; are listed. Elements included are H, Be, B, C,O, Al, Ti, Cr, Mn, Fe, Ni, Co, Y, ; Zr, Nb, Mo, Eu, Gd, Ta, W, Re, Th, U, and Pu. A discussion of the format and the ; method used to process these is included. (auth);

  5. SOME NEUTRON CROSS SECTIONS FOR MULTI-GROUP CALCULATIONS

    Microsoft Academic Search

    Tralli

    1958-01-01

    Chapters 1 through 4 deal, respectively, with neutron diffusion data, ; neutron sensor data, inelastic scattering data, and photon activation data. ; Chapter 5 consists of a list of the references to the literature cited in the ; first four chapters. The neutron diffusion data consist of the absorption, ; scattering, transport, and slowing-down cross sections. The neutron sensor data

  6. Measurement of Neutron Absorption Cross Sections with a Pile Oscillator

    Microsoft Academic Search

    J. I. Hoover; W. H. Jordan; C. D. Moak; L. Pardue; H. Pomerance; J. D. Strong; E. O. Wollan

    1948-01-01

    The following paper deals with the measurement of thermal neutron cross sections by a technique referred to as the pile oscillator. In this method, a neutron absorber is moved back and forth in a field of thermal neutrons such as that existing in a chain reactor. In the vicinity of the absorber there is a depression in the neutron flux

  7. RZ calculations for self shielded multigroup cross sections

    SciTech Connect

    Li, M.; Sanchez, R.; Zmijarevic, I.; Stankovski, Z. [Commissariat a l'Energie Atomique CEA, Direction de l'Energie Nucleaire, DEN/DM2S/SERMA/LENR, 91191 Gif-sur-Yvette Cedex (France)

    2006-07-01

    A collision probability method has been implemented for RZ geometries. The method accounts for white albedo, specular and translation boundary condition on the top and bottom surfaces of the geometry and for a white albedo condition on the outer radial surface. We have applied the RZ CP method to the calculation of multigroup self shielded cross sections for Gadolinia absorbers in BWRs. (authors)

  8. Nuclear cross sections, nuclear structure and stellar nucleosynthesis

    Microsoft Academic Search

    F.-K. Thielemann; D. Argast; F. Brachwitz; W. R. Hix; P. Höflich; M. Liebendörfer; G. Martinez-Pinedo; A. Mezzacappa; I. Panov; T. Rauscher

    2003-01-01

    The role of nuclear reactions (strong, weak and electromagnetic) and nuclear structure effects are discussed in a number of stellar applications. We address fusion cross sections in stellar evolution, neutrino-induced reactions in type II supernovae, electron captures in type Ia supernovae and fission in the r-process. All of this is discussed in the context of nucleosynthesis products and their role

  9. Effect of the interparticle contact cross section on SHS processes

    NASA Astrophysics Data System (ADS)

    Monasevich, T. V.

    1993-09-01

    The relationships between the contact cross section and porosity as well as the regions of dense packing porosity are obtained for systems for which the dependence of the rate of combustion on porosity was investigated. The maximum rate of combustion in the course of the synthesis of intermetallic compounds, borides, carbides, and silicides is observed in the case of the dense packing porosity.

  10. Measurement of Dijet Cross Sections With Leading Neutrons in

    E-print Network

    Measurement of Dijet Cross Sections With Leading Neutrons in Photoproduction at HERA 1 Armen. An analysis is presented of dijets in photoproduction at the ep collider HERA where a leading neutron. The average photon-proton center-of- mass energy is about 200 GeV. Mechanism of leading neutron production

  11. Cross Section; Half Longitudinal Section Showing Middle Wall Reinforced with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cross Section; Half Longitudinal Section Showing Middle Wall Reinforced with Arch; Part Long Section Showing Inside of External Side Wall; East Entrance; Part Side South External; Part Reflected Plan of Soffite of Floor; Part Reflected Plan of Soffite of Roof - Blenheim Covered Bridge, Spanning Schoharie River, North Blenheim, Schoharie County, NY

  12. Electron Photodetachment Cross Section of the Negative Ion of Fluorine

    Microsoft Academic Search

    A. Mandl

    1971-01-01

    The absorption spectrum of the negative ion of fluorine has been observed in shock-heated vapors of CsF. The photodetachment cross section of the fluorine ion has been measured in the wavelength region between 2100 and 3600 Å. Results are found to be in reasonable agreement with the calculated values of Robinson and Geltman.

  13. Propagation of sound waves in tubes of noncircular cross section

    NASA Technical Reports Server (NTRS)

    Richards, W. B.

    1986-01-01

    Plane-acoustic-wave propagation in small tubes with a cross section in the shape of a flattened oval is described. Theoretical descriptions of a plane wave propagating in a tube with circular cross section and between a pair of infinite parallel plates, including viscous and thermal damping, are expressed in similar form. For a wide range of useful duct sizes, the propagation constant (whose real and imaginary parts are the amplitude attenuation rate and the wave number, respectively) is very nearly the same function of frequency for both cases if the radius of the circular tube is the same as the distance between the parallel plates. This suggests that either a circular-cross-section model or a flat-plate model can be used to calculate wave propagation in flat-oval tubing, or any other shape tubing, if its size is expressed in terms of an equivalent radius, given by g = 2 x (cross-sectional area)/(length of perimeter). Measurements of the frequency response of two sections of flat-oval tubing agree with calculations based on this idea. Flat-plate formulas are derived, the use of transmission-line matrices for calculations of plane waves in compound systems of ducts is described, and examples of computer programs written to carry out the calculations are shown.

  14. Radiation pressure cross sections of model fluffy interstellar particles

    Microsoft Academic Search

    R. Saija; M. A. Iatì; A. Giusto; P. Denti; F. Borghese; C. Cecchi-Pestellini; S. Aiello; B. Barsella

    2003-01-01

    Radiation presssure forces affect the dynamical behaviour of dust particles in several astrophysical environments. For a given grain mass and composition, the optical response and the radiation pressure cross sections are critically dependent on morphology. It is likely that interstellar grains take their origin from aggregation of small particles thus resulting in more or less fluffy aggregates. These kind of

  15. Radiation pressure cross sections of model fluffy interstellar particles

    Microsoft Academic Search

    Rosalba Saija; Maria Antonia Iatì; Arianna Giusto; Paolo Denti; Ferdinando Borghese; Cesare Cecchi-Pestellini

    2003-01-01

    We calculated the radiation pressure cross sections of interstellar particles modeled as aggregates of up to 200 small spheres of astronomical silicates. The calculations were performed through the transition matrix method that, once the geometry of the aggregates has been chosen, does not require any approximations. The geometry of the particles has been set up by means of a random

  16. Absolute Photodetachment Cross-section Measurements for Hydrocarbon Chain Anions

    Microsoft Academic Search

    T. Best; R. Otto; S. Trippel; P. Hlavenka; A. von Zastrow; S. Eisenbach; S. Jézouin; R. Wester; E. Vigren; M. Hamberg; W. D. Geppert

    2011-01-01

    Absolute photodetachment cross sections have been measured for the hydrocarbon chain anions C n H--, n = 2, 4, and 6, which are relevant for an understanding of molecular clouds in the interstellar medium. Data have been obtained for different photon energies within approximately 1 eV of the detachment threshold. With our recently developed method we have achieved a precision

  17. Nuclear cross sections, cosmic ray propagation and source composition

    Microsoft Academic Search

    R. Silberberg; C. H. Tsao; J. R. Letaw

    1986-01-01

    Because cosmic rays with atomic number greater than 6 undergo nuclear composition transformations as a result of nuclear collisions in the interstellar gas, isotopic and elemental source composition have to be inferred in near-earth observation with a degree of uncertainty that is proportional to the uncertainty as to cross sections. The present consideration of these uncertainties proceeds with a comparison

  18. An experimental determination of the cross section for photodesorption

    Microsoft Academic Search

    E. B. Bourdon; R. H. Prince; W. W. Duley

    1982-01-01

    Measurement of the cross section for photodesorption of an absorbing molecule on a transparent substrate shows that this process is highly inefficient. Photodesorption yields under these conditions are some four orders of magnitude lower than previously assumed. Photodesorption of molecules from interstellar dust grains will be a highly inefficient process except in certain specialized situations.

  19. Partial Radiative Recombination Cross Sections for Excited States of Hydrogen

    Microsoft Academic Search

    Patricia Marie Fazio

    1984-01-01

    In calculating the radiative recombination cross sections for interstellar H II regions usually only the electric dipole term in the expansion of the interaction Hamiltonian is kept. However, conditions present in these regions permit recombination into highly excited states and the \\

  20. 8. Photograph of a line drawing. SHEET 8, CROSS SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photograph of a line drawing. SHEET 8, CROSS SECTION ON LINE EE; 9-16-1940. Assembly Building for Tank Plant for the Chrysler Corporation, Macomb County, Michigan. Delineator: E.B. - Detroit Arsenal, 6501 East Eleven Mile Road, Warren, Macomb County, MI

  1. 10. Photograph of a line drawing. SHEET 10, CROSS SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Photograph of a line drawing. SHEET 10, CROSS SECTION BB; 9-16-1940. Assembly Building for Tank Plant for the Chrysler Corporation, Macomb County, Michigan. Delineator: S.B. - Detroit Arsenal, 6501 East Eleven Mile Road, Warren, Macomb County, MI

  2. 7. Photograph of a line drawing. SHEET 7, CROSS SECTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Photograph of a line drawing. SHEET 7, CROSS SECTION ON LINE CC AND DD; 9-16-1940. Assembly Building for Tank Plant for the Chrysler Corporation, Macomb County, Michigan. Delineator: E.B. - Detroit Arsenal, 6501 East Eleven Mile Road, Warren, Macomb County, MI

  3. Measurement of inclusive jet cross sections in photoproduction at HERA

    Microsoft Academic Search

    I. Abt; T. Ahmed; V. Andreev; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; H. Bärwolff; J. Bán; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; G. Bertrand-Coremans; M. Besançon; P. Biddulph; E. Binder; A. Bischoff; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; J. Cvach; S. Dagoret; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. del Buono; M. Devel; A. de Roeck; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; R. Ebbinghaus; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; I. F. Fensome; J. Ferencei; F. Ferrarotto; K. Flamm; W. Flauger; M. Fleischer; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; A. Gellrich; M. Gennis; H. Genzel; R. Gerhards; L. Godfrey; U. Goerlach; L. Goerlich; M. Goldberg; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; D. Handschuh; E. M. Hanlon; M. Hapke; J. Harjes; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladký; K. C. Hoeger; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; T. Jansen; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; S. Kasarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; A. Leuschner; C. Leverenz; S. Levonian; D. Lewin; Ch. Ley; A. Lindner; G. Lindström; F. Linsel; J. Lipinski; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; V. Milone; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; K. Müller; P. Murín; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; D. Newton; D. Neyret; H. K. Nguyen; F. Niebergall; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; U. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. C. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; S. Prell; R. Prosi; G. Rädel; F. Raupach; K. Rauschnabel; P. Reimer; P. Ribarics; V. Riech; J. Riedlberger; S. Riess; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; V. Schröder; M. Schulz; A. Schwind; W. Scobel; U. Seehausen; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; L. Smolik; Y. Soloviev; H. Spitzer; P. Staroba; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; U. Stösslein; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; V. Tchernyshov; C. Thiebaux; G. Thompson; I. Tichomirov; P. Truöl; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallée; P. van Esch; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegner; H. P. Wellisch; S. Willard; M. Winde; G.-G. Winter; Th. Wolff; L. A. Womersley; A. E. Wright; N. Wulff; T. P. Yiou; J. Zácek; P. Závada; C. Zeitnitz; H. Ziaeepour; M. Zimmer; W. Zimmermann; F. Zomer

    1993-01-01

    The inclusive jet cross section in photoproduction has been measured as a function of transverse energy and pseudorapidity using the H 1 detector at the HERA electron-proton collider. The results are compared with leading order QCD calculations. Supported by the Swiss National Science Foundation.

  4. Cross-section of Calcite Crystal Covering in Jewel Cave

    USGS Multimedia Gallery

    Jewel Cave is currently the 3rd most extensive cave network in the world. It is believed to have formed completely underwater, thus leading to the extensive coating of calcite crystals. A cross-sectional view of the crystal coating can be seen in the center of the image, with the surface of the cal...

  5. Photodissociation of Acetaldehyde and the Photoionization Cross Section of HCO

    NASA Astrophysics Data System (ADS)

    Shubert, V. Alvin; Pratt, Stephen T.

    2010-06-01

    Acetaldehyde was photodissociated with near UV laser light, and the methyl (CH_3) and formyl (HCO) radical fragments were photoionized with vacuum ultraviolet (VUV) light. The fragments were detected by using both time of flight mass spectrometry and velocity ion map imaging. With the former technique, simultaneous detection of both fragments provided the intensity of HCO+ relative to CH_3+ with I(HCO+)/I(CH_3+) ? 0.8. Because the absolute photoionization cross section of the CH_3 radical has been characterized (? 5 Mb) at the VUV energies of interest, the absolute photoionization cross section of HCO could be determined from the intensity ratio, yielding an HCO cross section of ? 4 Mb at 10.3 eV. However, because some of the HCO fragments could be formed with enough internal energy to undergo secondary dissociation, velocity ion map imaging was employed to determine the extent of any secondary dissociation that occurred. The translational energy distributions obtained for both the CH_3 and HCO fragments are nearly identical, indicating that no HCO fragments underwent secondary dissociation. A surprising result was the smaller photoionization cross section of HCO relative to CH_3. Comparison to the isoelectronic species of NO will be discussed and a potential explanation will be offered for this observation. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract No. DE-AC02-06CH11357.

  6. Displacement Kerma Cross Sections for Neutron Interactions in Molybdenum

    SciTech Connect

    A. M. Ougouag; C. A. Wemple; C. D. Van Siclen

    2004-04-01

    Modifications to the displacement kerma cross section methods employed in the NJOY99 nuclear data processing code are described. Calculations were performed with the modified code for molybdenum using ENDF-6 neutron interaction data. Results are presented for a range of plausible Ed values.

  7. Stellar neutron capture cross sections of the Lu isotopes

    SciTech Connect

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Kazakov, L. [Forschungszentrum Karlsruhe, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany); Institute for Physics and Power Engineering, Obninsk, Kaluga-Region (Russian Federation)

    2006-01-15

    The neutron capture cross sections of {sup 175}Lu and {sup 176}Lu have been measured in the energy range 3-225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li(p,n){sup 7}Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4{pi} barium fluoride detector. The cross sections were determined relative to the gold standard using isotopically enriched as well as natural lutetium oxide samples. Overall uncertainties of {approx}1% could be achieved in the final cross section ratios to the gold standard, about a factor of 5 smaller than in previous works. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 and 100 keV. These values are systematically larger by {approx}7% than those reported in recent evaluations. These results are of crucial importance for the assessment of the s-process branchings at A 175/176.

  8. Nuclear Cross Section Library for Oil Well Logging Analysis

    Microsoft Academic Search

    I. Kodeli; S. Kitsos

    As part of the IRTMBA (Improved Radiation Transport Modelling for Borehole Applications) Project of the EU Community's 5th Programme a special purpose multigroup cross section library to be used in the deterministic (as well as Monte Carlo) oil well logging particle transport calculations was prepared. This library is expected to improve the prediction of the neutron and gamma spectra at

  9. Cross-sectional survey of hantavirus infection, Brazil.

    PubMed

    Limongi, Jean E; da Costa, Fabíola C; Pinto, Rogério M C; de Oliveira, Renata C; Bragagnolo, Camila; Lemos, Elba R S; de Paula, Márcia B C; Pajuaba Neto, Adalberto A; Ferreira, Marcelo S

    2009-12-01

    A cross-sectional serosurvey was conducted to assess the proportion of persons exposed to hantaviruses in a virus-endemic area of the state of Minas Gerais, Brazil. Findings of this study suggested the presence of > or =1 hantaviruses circulating in this region causing hantavirus pulmonary syndrome, mild disease, or asymptomatic infection. PMID:19961680

  10. Nomenclature a maximum width of the cross-section m

    E-print Network

    Roy, Subrata

    geometry coefficient Dh hydraulic diameter 4 / m f Fanning friction factor h height of the cross-section m / ) u(.) fluid axial velocity m/s V(.) dimensionless axial fluid velocity W average velocity m/s x, y. P. Celata et al. eds., Begell House, New York, pp. 108­113. 4 Jiang, P. X., Fan, M. H., Si, G. S

  11. Quality at general practice consultations: cross sectional survey

    Microsoft Academic Search

    John G R Howie; David J Heaney; Margaret Maxwell; Jeremy J Walker; George K Freeman; Harbinder Rai

    1999-01-01

    Objectives To measure quality of care at general practice consultations in diverse geographical areas, and to determine the principal correlates associated with enablement as an outcome measure. Design Cross sectional multipractice questionnaire based study. Setting Random sample of practices in four participating regions: Lothian, Coventry, Oxfordshire,

  12. Absolute cross sections for elastic electron scattering from 3-hydroxytetrahydrofuran

    NASA Astrophysics Data System (ADS)

    Milosavljevi?, A. R.; Blanco, F.; Maljkovi?, J. B.; Ševi?, D.; García, G.; Marinkovi?, B. P.

    2008-10-01

    The results of measurements and calculations of absolute cross sections for elastic electron scattering from the 3-hydroxytetrahydrofuran (3hTHF) (C4H8O2) molecule are reported. The measurements were performed using a crossed beam experimental setup, for an incident electron energy range of 40 300 eV and an overall scattering angle range of 10° 110°. Relative differential cross sections (DCSs) were measured both as a function of the angle and the incident energy and the absolute DCSs were determined using the relative flow technique. The calculations of molecular cross sections are based on a corrected form of the independent-atom method, known as the screen corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. Additional calculations are also done to investigate the influence of rotational excitations and low-angular behavior of SCAR DCSs. The calculated dataset includes differential, integral and total cross sections in the energy range from 5 eV to 10 000 eV. The present results are discussed regarding the most recent low-energy elastic DCSs for 3hTHF (Vizcaino et al 2008 New J. Phys. 10 053002), as well as the recent DCSs for molecules of similar structure (tetrahydrofuran and tetrahydrofurfuryl alcohol).

  13. 44. CROSS SECTION OF GRAND CANAL (not to scale, but ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. CROSS SECTION OF GRAND CANAL (not to scale, but representative of all six canals) Plan Sheet D-29976, Venice Canals Rehabilitation, Sheet No. 7 of 26 (delineated by T. Wu and E. Lee, March 1991) - Venice Canals, Community of Venice, Los Angeles, Los Angeles County, CA

  14. Strength and cross-sectional area of human skeletal muscle.

    PubMed Central

    Maughan, R J; Watson, J S; Weir, J

    1983-01-01

    The maximum voluntary force (strength) which could be produced by the knee-extensor muscles, with the knee held at a right angle, was measured in a group of healthy young subjects comprising twenty-five males and twenty-five females. Both legs were tested: data from the stronger leg only for each subject were used in the present study. Computed tomography was used to obtain a cross-sectional image of the subjects' legs at mid-thigh level, measured as the mid-point between the greater trochanter and upper border of the patella. The cross-sectional area of the knee-extensor muscles was determined from the image obtained by computer-based planimetry. The subjects' height and weight were measured. An estimate of body fat content was obtained from measurements of skinfold thicknesses and used to calculate lean body mass. Male subjects were taller (P less than 0.001), heavier (P less than 0.001), leaner (P less than 0.001) and stronger (P less than 0.001) than the female subjects. No significant correlation was found to exist between strength of the knee-extensor muscles and body weight in the male or in the female subjects. In the male subjects, but not in the female group, there was a positive correlation (r = 0.50; P less than 0.01) between strength and lean body mass. Muscle cross-sectional area of the male subjects was greater than that of the female subjects (P less than 0.001). The ratio of strength to cross-sectional area for the male was 9.49 +/- 1.34 (mean +/- S.D.). This is greater but not significantly so, than that for females (8.92 +/- 1.11). In both male and female groups, there was a significant (P less than 0.01) positive correlation between muscle strength and cross-sectional area. A wide variation in the ratio of strength to muscle cross-sectional area was observed. This variability may be a result of anatomical differences between subjects or may result from differences in the proportions of different fibre types in the muscles. The variation between subjects is such that strength is not a useful predictive index of muscle cross-sectional area. Images Plate 1 PMID:6875963

  15. Absolute photoionization cross-section of the methyl radical.

    SciTech Connect

    Taatjes, C. A.; Osborn, D. L.; Selby, T.; Meloni, G.; Fan, H.; Pratt, S. T.; Chemical Sciences and Engineering Division; SNL

    2008-01-01

    The absolute photoionization cross-section of the methyl radical has been measured using two completely independent methods. The CH{sub 3} photoionization cross-section was determined relative to that of acetone and methyl vinyl ketone at photon energies of 10.2 and 11.0 eV by using a pulsed laser-photolysis/time-resolved synchrotron photoionization mass spectrometry method. The time-resolved depletion of the acetone or methyl vinyl ketone precursor and the production of methyl radicals following 193 nm photolysis are monitored simultaneously by using time-resolved synchrotron photoionization mass spectrometry. Comparison of the initial methyl signal with the decrease in precursor signal, in combination with previously measured absolute photoionization cross-sections of the precursors, yields the absolute photoionization cross-section of the methyl radical; {sigma}{sub CH}(10.2 eV) = (5.7 {+-} 0.9) x 10{sup -18} cm{sup 2} and {sigma}{sub CH{sub 3}}(11.0 eV) = (6.0 {+-} 2.0) x 10{sup -18} cm{sup 2}. The photoionization cross-section for vinyl radical determined by photolysis of methyl vinyl ketone is in good agreement with previous measurements. The methyl radical photoionization cross-section was also independently measured relative to that of the iodine atom by comparison of ionization signals from CH{sub 3} and I fragments following 266 nm photolysis of methyl iodide in a molecular-beam ion-imaging apparatus. These measurements gave a cross-section of (5.4 {+-} 2.0) x 10{sup -18} cm{sup 2} at 10.460 eV, (5.5 {+-} 2.0) x 10{sup -18} cm{sup 2} at 10.466 eV, and (4.9 {+-} 2.0) x 10{sup -18} cm{sup 2} at 10.471 eV. The measurements allow relative photoionization efficiency spectra of methyl radical to be placed on an absolute scale and will facilitate quantitative measurements of methyl concentrations by photoionization mass spectrometry.

  16. Partial ionization cross-sections of acetone and 2-butanone

    NASA Astrophysics Data System (ADS)

    Vacher, J. R.; Jorand, F.; Blin-Simiand, N.; Pasquiers, S.

    2008-06-01

    The electron impact ionization of acetone and 2-butanone between 10 and 86 eV has been studied using mass spectrometry. The cross-sections are measured for the formation of molecular ions and major fragment ions which are produced. The present results display good agreement between the measured total ionization cross-sections and the calculated with the BEB model. The enthalpies of formation and the ionization energies of several fragments are evaluated using ab initio calculations. For each ketone, the molecular ion and the 43 amu ion contribute to about 80% of the total cross-section at 86 eV. The 43 amu ion, identified as the acetyl cation, is the most abundant above 15 eV. Other ions present in the spectra of acetone are (i) the 42 amu ion, detected in the range 12-86 eV, contributes to about 6% of the total cross-section at the maximum voltage used and is identified at low energy as a ketene cation, (ii) six other minor ions (39, 27, 26, 44, 29 and 15 amu) were detected above 17 eV. Five of them may result from dissociation reactions of the molecular ion while the methyl cation is issued from the 43 amu ion. In the spectra of 2-butanone, other ions are (i) the 57 amu ion detected in the range 11-86 eV and identified as the propionyl cation, contributes to about 6% of the total cross-section over the whole ionization energy range, (ii) four other minor ions (42, 29, 27 and 15 amu) were detected above 18 eV and there formation is similar to that of acetone. Effects of fragment size favour from the molecular ion, the formation of the 57 amu ion near the threshold, and at higher energy, the formation of the 43 amu ion.

  17. 162 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 33, NO. 1, JANUARY 1995 Behavior of the Ocean Radar Cross-

    E-print Network

    Miami, University of

    of the Ocean Radar Cross- Section at Low Incidence, Observed in the Vicinity of the Gulf Stream Danikle Hauser to examine the behaviour of the radar cross-sectionU' versus incidence @ and azimuth 4. Although, considerableeffort has been devoted 0to the understanding of the behaviour of radar signal backscattered from

  18. Evaluation of Neutron Cross Section of 27 Fission Product Nuclides Important for Fast Reactor

    Microsoft Academic Search

    Shungo IIJIMA; Tsuneo NAKAGAWA; Yasuyuki KIKUCHI; Masayoshi KAWAI; Hiroyuki MATSUNOBU; Koichi MAKI; Sin-iti IGARASI

    1977-01-01

    Results of evaluation of neutron cross sections are presented for 27 fission product nuclides selected as being most important for fast reactor calculation. The cross sections considered are total, elastic scattering, inelastic scattering and capture cross sections in the energy range from thermal to 15 MeV. Thermal and resonance cross sections were calculated from resonance parameters. The calculated thermal capture

  19. Very small (n,gamma) cross sections: two measurements for primordial and stellar nucleosynthesis

    Microsoft Academic Search

    U. Ratzel; M. Wiescher; H. Beer; F. Käppeler; R. Steiniger

    1989-01-01

    The measurement of neutron capture cross sections via the activation technique has been extended to cross sections in the mub range. The knowledge of small cross sections is important for the abundances of neutron magic nuclei, for the role of neutron poisons, and for primordial nucleosynthesis. Wherever the activation technique can be applied, such small cross sections can be determined

  20. VALIDATION OF A RADAR DOPPLER SPECTRA SIMULATOR USING MEASUREMENTS FROM THE ARM CLOUD RADARS

    E-print Network

    VALIDATION OF A RADAR DOPPLER SPECTRA SIMULATOR USING MEASUREMENTS FROM THE ARM CLOUD RADARS model output with the Doppler spectra recorded from the vertically pointing cloud radars at the ARM are then used to compute the backscattering cross-section and fall velocities, while the turbulence

  1. A.Baghdasaryan. Jet Cross Sections and S at HERA. LOW X 2008, Kolimpari, Greece, July, 6-10 1 Jet Cross Sections and s at

    E-print Network

    A.Baghdasaryan. Jet Cross Sections and S at HERA. LOW X 2008, Kolimpari, Greece, July, 6-10 1 Jet Cross Sections and s at HERA Low X 2008, 6-10 July Kolimpary, Greece Artem Baghdasaryan Yerevan Physics.Baghdasaryan. Jet Cross Sections and S at HERA. LOW X 2008, Kolimpari, Greece, July, 6-10 2 Motivation Jets physics

  2. A measurement of the U 233 , U 235 , Pu 239 total cross sections. As well as the fission cross section of U 235 for resonance neutrons

    Microsoft Academic Search

    V. V. Sokolovsky; V. V. Vladimirsky; I. A. Radkevich; A. A. Panov

    1957-01-01

    The measurement of the interaction cross sections between resonance neutrons and fissionable isotopes are of definite importance both for reactor calculations and for the construction of various nuclear models. In this work we present the results of measurements of the U233, U235, and Pu239 total cross sections, as well as the fission cross section of U235. The measurements were performed

  3. TXSAMC (transport cross sections from applied Monte Carlo): a new tool for generating shielded multigroup cross sections 

    E-print Network

    Hiatt, Matthew Torgerson

    2009-06-02

    ..............................................................................................................................166 x LIST OF FIGURES FIGURE Page 1 Comparison of multigroup and continuous energy cross sections for 23Na..........4 2 TXSAMC process flowchart..................................................................................30 3 SSR layout in x-y plane. .....................................................................................42 4 ?Partial" percent errors in each energy group for reaction-rate densities in SSR...

  4. Calculation of photoionization cross section near auto-ionizing lines and magnesium photoionization cross section near threshold

    NASA Technical Reports Server (NTRS)

    Moore, E. N.; Altick, P. L.

    1972-01-01

    The research performed is briefly reviewed. A simple method was developed for the calculation of continuum states of atoms when autoionization is present. The method was employed to give the first theoretical cross section for beryllium and magnesium; the results indicate that the values used previously at threshold were sometimes seriously in error. These threshold values have potential applications in astrophysical abundance estimates.

  5. Joint strength in RCS frames 

    E-print Network

    Kirby, Cynthia Dawn

    1998-01-01

    for the addition of a RC slab, cover plates, and band plates. Results indicated that the addition of a reinforced concrete slab compositely connected to the steel beams framing into a typical RCS joints as defined by the ASCE guidelines (1994), improved the joint...

  6. Orbiter OMS and RCS technology

    NASA Technical Reports Server (NTRS)

    Boudreaux, R. A.

    1982-01-01

    Orbiter Orbital Maneuver Subsystem (OMS) and Reaction Control Subsystem (RCS) tankage has proved to be highly successful in shuttle flights on-orbit propellant transfer tests were done. Tank qualification tests along with flight demonstrations were carried out future uses of storable propellants are cited.

  7. Development and characterization analysis of a radar polarimeter 

    E-print Network

    Bong, Soei Siang

    1984-01-01

    Measurement of the Minimum Detectable Signal and the Typical Power Output . . 83 14 Radar Cross Section Calculation for the Three Different Radar Frequencies Based Upon a Constant Return Power . . 85 15 Summary of the Component Parameters for the Power... minimum detectable signal can be calculated. The minimum defectable signal and the radar cross section of a target are statistical in nature. There is no statistical expression in equation (4b) to describe the statistical nature of the minimum 50...

  8. Aircraft Routing under the Risk of Detection Michael Zabarankin,1

    E-print Network

    Uryasev, Stanislav

    with variable radar cross-section (RCS) subject to a constraint on the trajectory length have been developed. The impact of ellipsoid shape on the geometry of an optimal trajectory as well as the impact of variable RCS path generation in two-dimensional (2-D) space with constant radar cross- section (RCS) of the aircraft

  9. Quantifying and predicting interpretational uncertainty in cross-sections

    NASA Astrophysics Data System (ADS)

    Randle, Charles; Bond, Clare; Monaghan, Alison; Lark, Murray

    2015-04-01

    Cross-sections are often constructed from data to create a visual impression of the geologist's interpretation of the sub-surface geology. However as with all interpretations, this vision of the sub-surface geology is uncertain. We have designed and carried out an experiment with the aim of quantifying the uncertainty in geological cross-sections created by experts interpreting borehole data. By analysing different attributes of the data and interpretations we reflect on the main controls on uncertainty. A group of ten expert modellers at the British Geological Survey were asked to interpret an 11.4 km long cross-section from south-east Glasgow, UK. The data provided consisted of map and borehole data of the superficial deposits and shallow bedrock. Each modeller had a unique set of 11 boreholes removed from their dataset, to which their interpretations of the top of the bedrock were compared. This methodology allowed quantification of how far from the 'correct answer' each interpretation is at 11 points along each interpreted cross-section line; through comparison of the interpreted and actual bedrock elevations in the boreholes. This resulted in the collection of 110 measurements of the error to use in further analysis. To determine the potential control on uncertainty various attributes relating to the modeller, the interpretation and the data were recorded. Modellers were asked to fill out a questionnaire asking for information; such as how much 3D modelling experience they had, and how long it took them to complete the interpretation. They were also asked to record their confidence in their interpretations graphically, in the form of a confidence level drawn onto the cross-section. Initial analysis showed the majority of the experts' interpreted bedrock elevations within 5 metres of those recorded in the withheld boreholes. Their distribution is peaked and symmetrical about a mean of zero, indicating that there was no tendency for the experts to either under or over estimate the elevation of the bedrock. More complex analysis was completed in the form of linear mixed effects modelling. The modelling was used to determine if there were any correlations between the error and any other parameter recorded in the questionnaire, section or the initial dataset. This has resulted in the determination of both data based and interpreter based controls on uncertainty, adding insight into how uncertainty can be predicted, as well as how interpretation workflows can be improved. Our results will inform further experiments across a wide variety of geological situations to build understanding and best practice workflows for cross-section interpretation to reduce uncertainty.

  10. Absolute photoionization cross sections of the ions Ca+ Ni+

    NASA Astrophysics Data System (ADS)

    Hansen, J. E.; Kjeldsen, H.; Folkmann, F.; Martins, M.; West, J. B.

    2007-01-01

    Absolute measurements of the photoionization cross sections of the singly charged ions in the sequence Ca to Ni are presented, focussing on the 3p ? 3d resonance region. Major differences are found in both spectral structure and cross section as the 3d shell is filled progressively. The behaviour of the total oscillator strength is studied as well as its relation to the collapse of the 3d orbital. The 3p53d 1P term is found to have an influence on the spectra even when further 3d electrons are added and this dependence combined with the effect of Hund's rule leads to a considerable simplification in the structure of the absorption spectra before the half-filled 3d shell, while from the half-filled 3d shell Hund's rule is the main simplifying effect.

  11. Shear viscosity of hadrons with K-matrix cross sections

    NASA Astrophysics Data System (ADS)

    Wiranata, Anton; Koch, Volker; Prakash, Madappa; Wang, Xin Nian

    2013-10-01

    Shear viscosity ? and entropy density s of a hadronic resonance gas are calculated using the Chapman-Enskog and virial expansion methods using the K-matrix parametrization of hadronic cross sections which preserves the unitarity of the T matrix. In the ?-K-N-? mixture considered, a total of 57 resonances up to 2 GeV were included. Comparisons are also made to results with other hadronic cross sections such as the Breit-Wigner (BW) and, where available, experimental phase shift parameterizations. Hadronic interactions forming resonances are shown to decrease the shear viscosity and increase the entropy density leading to a substantial reduction of ?/s as the QCD phase transition temperature is approached.

  12. Realistic Calculations for Neutrino-Nucleus Reactions Cross sections

    SciTech Connect

    Chasioti, V. C.; Divari, P. C.; Kosmas, T. S. [Theoretical Physics Section, University of Ioannina, GR 45110 Ioannina (Greece)

    2007-10-12

    We evaluate differential and integrated neutrino-nucleus reactions cross sections for low and intermediate neutrino energies (0 MeV{<=}E{sub {nu}}{<=}100 MeV). We investigate the dependence on the scattering angle and initial neutrino-energy of the Fermi and Gamow-Teller type transition rates. The required many-body nuclear wave-functions are calculated by utilizing the quasi-particle random phase approximation. The results presented refer to the neutral-current scattering of {nu}{sub e} on the nuclear isotopes {sup 16}O and {sup 98}Mo which play a significant role in astrophysical neutrino studies. By exploiting our exclusive cross sections, we explore the nuclear response for these detectors to supernova neutrinos assuming Fermi-Dirac distributions for the supernova neutrino spectra.

  13. Carbon Fragmentation Cross Sections for Hadrontherapy and Space Radiation Protection

    NASA Astrophysics Data System (ADS)

    De Napoli, M.; Agodi, C.; Cirrone, G. A. P.; Cuttone, G.; Nicolosi, D.; Pandola, L.; Raciti, G.; Romano, F.; Sardina, D.; Scuderi, V.; Tropea, S.; Bondì, M.; Cappuzzello, F.; Carbone, D.; Cavallaro, M.

    2014-05-01

    Fragmentation reactions represent a serious complication in hadrontherapy and space radiation protection. In order to predict their effects, both reliable Monte Carlo codes and experimental data are needed. The shortage of precise measurements, especially of double differential cross sections, has triggered many dedicated experiments at relativistic energies. Aiming to explore the Fermi energy regime, as well, where different reaction mechanisms are involved, we measured the 12C fragmentation at 62 AMeV on a 12C and a 197Au target. A high granularity Si-CsI hodoscope allowed to identify the charge and the mass of detected fragments and measure their energy and emission angle. In this work we report the double differential cross sections for the production of different fragments as a function of the emission angle. Experimental results are compared with the GEANT-4 Monte Carlo predictions performed using two reaction models, the Quantum Molecular Dynamic and the Binary Light Ion Cascade.

  14. Evaluation of Neutron Resonance Cross Section Data at GELINA

    NASA Astrophysics Data System (ADS)

    Schillebeeckx, P.; Becker, B.; Capote, R.; Emiliani, F.; Guber, K.; Heyse, J.; Kauwenberghs, K.; Kopecky, S.; Lampoudis, C.; Massimi, C.; Mondelaers, W.; Moxon, M.; Noguere, G.; Plompen, A. J. M.; Pronyaev, V.; Siegler, P.; Sirakov, I.; Trkov, A.; Volev, K.; Zerovnik, G.

    2014-05-01

    Over the last decade, the EC-JRC-IRMM, in collaboration with other institutes such as INRNE Sofia (BG), INFN Bologna (IT), ORNL (USA), CEA Cadarache (FR) and CEA Saclay (FR), has made an intense effort to improve the quality of neutron-induced cross section data in the resonance region. These improvements relate to both the infrastructure of the facility and the measurement setup, and the data reduction and analysis procedures. As a result total and reaction cross section data in the resonance region with uncertainties better than 0.5 % and 2 %, respectively, can be produced together with evaluated data files for both the resolved and unresolved resonance region. The methodology to produce full ENDF compatible files, including covariances, is illustrated by the production of resolved resonance parameter files for 241Am, Cd and W and an evaluation for 197Au in the unresolved resonance region.

  15. Generalized x-ray scattering cross section from nonequilibrium plasmas

    SciTech Connect

    Gregori, G.; Glenzer, S. H.; Landen, O. L. [CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, Great Britain and Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, Great Britain (United Kingdom); Lawrence Livermore National Laboratory, University of California, P.O. Box 808, California 94551 (United States)

    2006-08-15

    We propose a modified x-ray form factor that describes the scattering cross section in warm dense matter valid for both the plasma and the solid (crystalline) state. Our model accounts for the effect of lattice correlations on the electron-electron dynamic structure, as well as provides a smooth transition between the solid and the plasma scattering cross sections. In addition, we generalize the expression of the dynamic structure in the case of a two-temperature system (with different electron and ion temperatures). This work provides a unified description of the x-ray scattering processes in warm and dense matter, as the one encountered in inertial confinement fusion, laboratory astrophysics, material science, and high-energy density physics and it can be used to verify temperature relaxation mechanisms in such environments.

  16. A Study on 19F( n,?) Reaction Cross Section

    NASA Astrophysics Data System (ADS)

    U?ur, F. A.; Tel, E.; Gökçe, A. A.

    2013-06-01

    In this study, cross sections of neutron induced reactions have been investigated for fluorine target nucleus. The calculations have been made on the excitation functions of 19F ( n,?), 19F( n,x?) reactions. Fluorine (F) and its molten salt compounds (LiF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure and also the molten salt compounds are also a good neutron moderator. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The obtained results have been discussed and compared with the available experimental data.

  17. Experimental validation of lead cross sections for scale and MCNP

    SciTech Connect

    Henrikson, D.J.

    1995-12-01

    Moving spent nuclear fuel between facilities often requires the use of lead-shielded casks. Criticality safety that is based upon calculations requires experimental validation of the fuel matrix and lead cross section libraries. A series of critical experiments using a high-enriched uranium-aluminum fuel element with a variety of reflectors, including lead, has been identified. Twenty-one configurations were evaluated in this study. The fuel element was modelled for KENO V.a and MCNP 4a using various cross section sets. The experiments addressed in this report can be used to validate lead-reflected calculations. Factors influencing calculated k{sub eff} which require further study include diameters of styrofoam inserts and homogenization.

  18. Accurate Development of Thermal Neutron Scattering Cross Section Libraries

    SciTech Connect

    Hawari, Ayman; Dunn, Michael

    2014-06-10

    The objective of this project is to develop a holistic (fundamental and accurate) approach for generating thermal neutron scattering cross section libraries for a collection of important enutron moderators and reflectors. The primary components of this approach are the physcial accuracy and completeness of the generated data libraries. Consequently, for the first time, thermal neutron scattering cross section data libraries will be generated that are based on accurate theoretical models, that are carefully benchmarked against experimental and computational data, and that contain complete covariance information that can be used in propagating the data uncertainties through the various components of the nuclear design and execution process. To achieve this objective, computational and experimental investigations will be performed on a carefully selected subset of materials that play a key role in all stages of the nuclear fuel cycle.

  19. Nonlocal effects in the nucleus-nucleus fusion cross section

    SciTech Connect

    Galetti, D.; Candido Ribeiro, M.A. (Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, CEP 01405, Sao Paulo, Sao Paulo (Brazil))

    1994-10-01

    Effects of the nonlocality of factorizable potentials are taken into account in the calculation of nucleus-nucleus fusion cross section through an effective mass approach. This cross section makes use of the tunneling factor calculated for the nonlocal barrier, without the explicit introduction of any result coming from coupled channel calculation, besides the approximations of Hill-Wheeler and Wong. Its new expression embodies the nonlocal effects in a factor which redefines the local potential barrier curvature. Applications to different systems, namely, [sup 16]O+[sup 59]Co, [sup 16,18]O+[sup 58,60,64]Ni, and [sup 16,18]O+[sup 63,65]Cu are presented, where the nonlocal range is treated as a free parameter.

  20. Cross sections for atomic displacements in solids by fast positrons

    SciTech Connect

    Oen, Ordean S.

    1987-09-01

    The Mott series has been used to calculate the cross section for atomic displacements produced in elastic collisions between relativistic positrons and atomic nuclei. The Kinchin and Pease displacement model was used. Several elements spanning the atomic table were treated using positron energies ranging from threshold to several tens of MeV. The results are compared with previous calculations for relativistic electrons. It is found that for the same energy and atomic number the positron cross sections are always smaller (up to a factor of 5 or more). It is also found that the McKinley-Fesbach formula which is frequently used in radiation damage analysis is even less reliable for positrons than for electrons. 9 refs.

  1. Cross sections for atomic displacements in solids by fast positrons

    NASA Astrophysics Data System (ADS)

    Oen, Ordean S.

    1988-06-01

    The Mott series has been used to calculate the cross section for atomic displacements produced in elastic collisions between relativistic positrons and atomic nuclei. The Kinchin and Pease displacement model was used. Several elements spanning the atomic table were treated using positron energies ranging from threshold to several tens of MeV. The results are compared with previous calculations for relativistic electrons. It is found that for the same energy and atomic number the positron cross sections are always smaller (up to a factor of 5 or more). It is also found that the McKinley-Feshbach formula, which is frequently used in radiation damage analysis, is even less reliable for positrons than for electrons.

  2. Hadronic Cross Section Measurement at Bes-Iii

    NASA Astrophysics Data System (ADS)

    Schumann, Sven

    2014-12-01

    Measurements of the R ratio are closely related to two pre quantities, the anomalous magnetic moment of the muon (g - 2), and the value of the electromagnetic fine structure constant ? { QED}(M2Z). Hadronic contributions to both quantities can be derived via dispersion integrals, using experimental R data as input. For the phenomenological evaluations of these contributions, different energy ranges of hadronic cross section data are required. At BES-III, Initial State Radiation (ISR) from an existing ?(3770) dataset will be used for measurements of hadronic cross sections below ? s = 2 GeV, while for higher energies a dedicated energy scan program will be performed up to ? s = 4.5 GeV.

  3. First measurements of positronium total scattering cross sections

    Microsoft Academic Search

    D. M. Spektor; D. A. L. Paul

    1975-01-01

    A new type of experiment has been devised in which ortho-positronium diffusion to the metal walls of a series of parallel-sided\\u000a cells is studied by measuring the annihilation lifetimes. Experimental results are subjected to an analysis in which two parameters\\u000a are varied to give a best fit, one of the two parameters being the scattering cross section. The method requires

  4. Workshop on a Cross Section of Archean Crust

    NASA Technical Reports Server (NTRS)

    Ashwal, L. D. (editor); Card, K. D. (editor)

    1983-01-01

    Various topics relevant to crustal genesis, especially the relationship between Archean low - and high-grade terrains, were discussed. The central Superior Province of the Canadian Shield was studied. Here a 120 km-wide transition from subgreenschist facies rocks of the Michipicoten greenstone belt to granulite facies rocks of the Kapuskasing structural zone represents an oblique cross section through some 20 km of crust, uplifted along a northwest-dipping thrust fault.

  5. Differential collision cross-sections for atomic oxygen

    NASA Technical Reports Server (NTRS)

    Torr, Douglas G.

    1991-01-01

    Differential collision cross-sections of O on N2 and other gases were measured to understand vehicle-environmental contamination effects in orbit. The following subject areas are also covered: groundbased scientific observations of rocket releases during NICARE-1; data compression study for the UVI; science priorities for UV imaging in the mid-1990's; and assessment of optimizations possible in UV imaging systems.

  6. Neutrino and Antineutrino Cross sections at MiniBooNE

    SciTech Connect

    Dharmapalan, Ranjan; /Alabama U.

    2011-10-01

    The MiniBooNE experiment has reported a number of high statistics neutrino and anti-neutrino cross sections -among which are the charged current quasi-elastic (CCQE) and neutral current elastic (NCE) neutrino scattering on mineral oil (CH2). Recently a study of the neutrino contamination of the anti-neutrino beam has concluded and the analysis of the anti-neutrino CCQE and NCE scattering is ongoing.

  7. Neutron-Induced Cross Sections Measurements of Calcium

    SciTech Connect

    Guber, Klaus H [ORNL; Kopecky, S. [EC-JRC-IRMM, Geel, Belgium; Schillebeeckx, P. [EC-JRC-IRMM, Geel, Belgium; Kauwenberghs, K. [EC-JRC-IRMM, Geel, Belgium; Siegler, P. [EC-JRC-IRMM, Geel, Belgium

    2013-01-01

    To support the US Department of Energy Nuclear Criticality Safety Program neutron induced cross section experiments were performed at the Geel Electron Linear Accelerator of the Institute for Reference Material and Measurements of the Joint Research Centers, European Union. Neutron capture and transmission measurements were carried out using a metallic calcium sample. The obtained data will be used for a new calcium evaluation, which will be submitted with its covariances to the ENDBF/B nuclear data base.

  8. Top quark pair production cross section at the Tevatron

    SciTech Connect

    Cortiana, Giorgio; /INFN, Padua /Padua U.

    2008-04-01

    Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.

  9. Top Quark Production Cross Section at the Tevatron

    SciTech Connect

    Shabalina, E.; /Chicago U.

    2006-05-01

    An overview of the preliminary results of the top quark pair production cross section measurements at a center-of-mass energy of 1.96 TeV carried out by the CDF and D0 collaborations is presented. The data samples used for the analyses are collected in the current Tevatron run and correspond to an integrated luminosity from 360 pb{sup -1} up to 760 pb{sup -1}.

  10. Observation of very large electromagnetic dissociation cross sections

    Microsoft Academic Search

    John C. Hill; F. K. Wohn; D. D. Schwellenbach; A. R. Smith

    1991-01-01

    An electromagnetic dissociation (ED) cross section of 3.16+\\/-0.23 b was observed for 197Au(238U, X)196Au with 0.96 GeV\\/ nucleon 238U projectiles. The gross features of ED are reproduced in a Weizsäcker-Williams (WW) calculation, but the projectile charge dependence is weaker than expected from WW. WW calculations are extended to the regime of energies of the next generation of relativistic heavy-ion colliders.

  11. Coupling Extraction From Off-Shell Cross-sections

    E-print Network

    Baradhwaj Coleppa; Tanumoy Mandal; Subhadip Mitra

    2014-10-09

    In this note, we present a novel method of extracting the couplings of a new heavy particle to the Standard Model states. Contrary to the usual discovery process which involves studying the on-shell production, we look at regions away from resonance to take advantage of the simple scaling of the cross-section with the couplings. We apply the procedure to the case of a heavy quark as an illustration.

  12. Inclusive parton cross sections in photoproduction and photon structure

    E-print Network

    Ahmed, T; Andrieu, B; Appuhn, R D; Arpagaus, M; Aïd, S; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bergstein, H; Bernardi, G; Bernet, R; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Brasse, F W; Braunschweig, W; Brisson, V; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Buschhorn, G W; Bán, J; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Campbell, A J; Carli, T; Charles, F; Charlet, M; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Colombo, M G; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Coutures, C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; De Wolf, E A; Del Buono, L; Delcourt, B; Di Nezza, P; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duboc, J; Duhm, H; Düllmann, D; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichenberger, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Erlichmann, H; Evrard, E; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Forbush, M; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gamerdinger, K; Garvey, J; Gayler, J; Gebauer, M; Gellrich, A; Genzel, H; Gerhards, R; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; González-Pineiro, B; Gorelov, I V; Goritchev, P A; Grab, C; Greenshaw, T J; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Haidt, Dieter; Hajduk, L; Hamon, O; Hampel, M; Hanlon, E M; Hapke, M; Haynes, W J; Heatherington, J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hildesheim, W; Hill, P; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Horisberger, R P; Hudgson, V L; Huet, Patrick; Hufnagel, H; Höppner, M; Hütte, M; Ibbotson, M; Itterbeck, H; Jabiol, M A; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Johnson, L; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kant, D; Kaschowitz, R; Kasselmann, P; Kathage, U; Katzy, J M; Kaufmann, H H; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Ko, W; Kolanoski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Krüger, U P; Krüner-Marquis, U; Kubenka, J P; Kuhlen, M; Kurca, T; Kurzhöfer, J; Kuznik, B; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Lamarche, F; Lander, R; Landon, M P J; Lange, W; Lanius, P; Laporte, J F; Lebedev, A; Leverenz, C; Levonian, S; Ley, C; Lindner, A; Lindström, G; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lohmander, H; Lomas, J W; Lubimov, V; López, G C; Lüke, D; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, R D; Martyn, H U; Martyniak, J; Masson, S; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Mercer, D; Merz, T; Meyer, C A; Meyer, H; Meyer, J; Migliori, A; Mikocki, S; Milstead, D; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Obrock, U; Olsson, J E; Ozerov, D; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Peppel, E; Phillips, J P; Pichler, C; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Prosi, R; Pérez, E; Rabbertz, K; Raupach, F; Reimer, P; Reinshagen, S; Ribarics, P; Rick, Hartmut; Riech, V; Riedlberger, J; Riess, S; Rietz, M; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rylko, R; Rädel, G; Rüter, K; Sahlmann, N; Salesch, S G; Sankey, D P C; Schacht, P; Schiek, S; Schleper, P; Schmidt, C; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schwind, A; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shooshtari, H; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Spiekermann, J; Spielman, S; Spitzer, H; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Stella, B; Stephens, K; Stier, J; Stiewe, J; Stolze, K; Strachota, J; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Sánchez, E; Tapprogge, Stefan; Thiebaux, C; Thompson, G; Truöl, P; Turnau, J; Tutas, J; Uelkes, P; Usik, A

    1995-01-01

    Photoproduction of 2-jet events is studied with the H1 detector at HERA. Parton cross sections are extracted from the data by an unfolding method using leading order parton-jet correlations of a QCD generator. The gluon distribution in the photon is derived in the fractional momentum range 0.04\\le x_\\gamma \\le 1 at the average factorization scale 75 GeV^2.

  13. Nucleon-nucleon cross sections in dense nuclear matter

    Microsoft Academic Search

    H. F. Zhang; Z. H. Li; U. Lombardo; P. Y. Luo; F. Sammarruca; W. Zuo

    2007-01-01

    We present microscopic calculations of cross sections for scattering of identical and nonidentical nucleons in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Argonne v14 potential including the contribution of microscopic three-body forces. We investigate separately the effects of three-body forces on the effective mass and on the scattering amplitude. In the present calculation, the

  14. Nucleon-nucleon cross sections in dense nuclear matter

    Microsoft Academic Search

    H. F. Zhang; Z. H. Li; U. Lombardo; P. Y. Luo; W. Zuo; F. Sammarruca

    2007-01-01

    We present microscopic calculations of cross sections for scattering of identical and nonidentical nucleons in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Argonne v potential including the contribution of microscopic three-body forces. We investigate separately the effects of three-body forces on the effective mass and on the scattering amplitude. In the present calculation, the

  15. Neutron Activation Cross Sections with Sb-Be Neutrons

    Microsoft Academic Search

    R. L. Macklin; N. H. Lazar; W. S. Lyon

    1957-01-01

    The neutron activation cross sections near 25 kev have been measured for about 50 nuclei. Gamma-ray scintillation spectrometers with known efficiency were used to compare the radioactivities produced by the several nuclei with I128. This gave a significant increase in sensitivity and precision over direct beta-counting methods in many cases. Absolute standardization was obtained through scintillation-beta-counting the I128 in NaI(Tl)

  16. Measurements of 14 MeV Neutron Activation Cross Sections

    Microsoft Academic Search

    Rudolf Pepelnik; Bernd Anders; Beni M. Bahal

    1986-01-01

    In the neutron generator facility KORONA a neutron flux of 3 · 10 n\\/cms with an energy of 14.7 ± 0.3 MeV is available. A fast rabbit system transfers samples within 140 ms to the detector station. For activation analysis work a variety of reaction cross sections were determined:The reaction products have half-lives between 0.35 s and 64 d. For

  17. The thermal neutron activation cross section of 105 Ru

    Microsoft Academic Search

    B. L. Sharma

    1960-01-01

    Summary  In order to calculate the thermal neutron activation cross section of105Ru, the enriched104Ru was exposed to a thermal neutron flux of 1.2·1014 neutrons cm?2s?1. After the decay of the 40-day activity of103Ru, the silver impurity was removed and the contributions from Co and Eu impurities were subtracted. The ?-ray energies and\\u000a the coincidence results were consistent with the previously established

  18. Cross section uncertainties in the gallium neutrino source experiments

    Microsoft Academic Search

    W. C. Haxton

    1998-01-01

    The 51Cr neutrino source experiments play a unique role in testing overall operations of the GALLEX and SAGE solar neutrino experiments. Recently Hata and Haxton argued that the excited-state contribution to the 71Ga cross section for 51Cr neutrino absorption might not be known reliably, despite forward-angle (p,n) measurements. A large-basis shell model calculation reported here indicates that the unusual situation

  19. Top-Quark Cross Section and Properties at the Tevatron

    SciTech Connect

    Wagner, Wolfgang; /Wuppertal U.

    2009-09-01

    At the Tevatron, the collider experiments CDF and D0 have data sets at their disposal that compromise several hundreds of reconstructed top-antitop-quark pairs and allow for precision measurements of the cross section and production and decay properties. Besides comparing the measurements to standard model predictions, these data sets open a window to physics beyond the standard model. Dedicated analyses look for new heavy gauge bosons, fourth generation quarks, and flavor-changing neutral currents.

  20. Emission and absorption cross section of thulium doped silica fibers

    Microsoft Academic Search

    Søren Dyøe Agger; Jorn Dyøe Hedegaard Povlsen

    2006-01-01

    A thorough investigation of the emission and absorption spectra of the (3F4,3H6) band in thulium doped silica fibers has been performed. All the basic parameters of thulium in silica have been extracted with the purpose of further analysis in laser and amplifier simulations. The experimental methods used to obtain the scaled cross sections have been carefully selected in order to

  1. ACTIVIA: Calculation of Isotope Production Cross-sections and Yields

    E-print Network

    Back, J J

    2007-01-01

    We present a C++ computer package, ACTIVIA, that can calculate target-product cross-sections and the production and decay yields of isotopes from cosmic ray activation using data tables and semi-empirical formulae. We describe the structure and user interface of the computer code as well as provide comparisons between the calculations and experimental results. We also outline suggestions on how the code can be improved and extended for other applications.

  2. ACTIVIA: Calculation of Isotope Production Cross-sections and Yields

    E-print Network

    J. J. Back; Y. A. Ramachers

    2008-01-15

    We present a C++ computer package, ACTIVIA, that can calculate target-product cross-sections and the production and decay yields of isotopes from cosmic ray activation using data tables and semi-empirical formulae. We describe the structure and user interface of the computer code as well as provide comparisons between the calculations and experimental results. We also outline suggestions on how the code can be improved and extended for other applications.

  3. ACTIVIA: Calculation of isotope production cross-sections and yields

    Microsoft Academic Search

    J. J. Back; Y. A. Ramachers

    2008-01-01

    We present a C++ computer package, ACTIVIA, that can calculate target–product cross-sections and the production and decay yields of isotopes from cosmic ray activation using data tables and semi-empirical formulae. We describe the structure and user interface of the computer code as well as provide comparisons between the calculations and experimental results. We also outline suggestions on how the code

  4. Overview of recent U235 neutron cross section evaluation work

    SciTech Connect

    Lubitz, C. [Lockheed Martin Corp., Schenectady, NY (United States)

    1998-10-01

    This report is an overview (through 1997) of the U235 neutron cross section evaluation work at Oak Ridge National Laboratory (ORNL), AEA Technology (Harwell) and Lockheed Martin Corp.-Schenectady (LMS), which has influenced, or appeared in, ENDF/B-VI through Release 5. The discussion is restricted to the thermal and resolved resonance regions, apart from some questions about the unresolved region which still need investigation. The important role which benchmark testing has played will be touched on.

  5. Angular differential cross section calculations for ion-helium collisions

    NASA Astrophysics Data System (ADS)

    Zapukhlyak, M.; Kirchner, T.

    2009-11-01

    We have calculated projectile angular-differential cross sections for various processes in ion-helium collisions. Key ingredients of our approach are the independent electron model, the two-center basis generator method for orbital propagation, and the eikonal approximation for the extraction of angular-differential scattering amplitudes. In general, we find good agreement with measurements; in some cases even for two-electron processes, although correlation effects are not taken into account.

  6. Cross-sectional analysis of the chest and abdominal wall

    SciTech Connect

    Wechsler, R.J.

    1989-01-01

    This book covers the musculoskeletal envelope of the internal viscera as seen in cross section on computed tomographic (CT), magnetic resonance (MR), and ultrasound images. The contents proceed on the basis of anatomic areas, from the axilla and supraclavicular fossa, through the thoracic and abdominal wall and paraspinal musculature, to the glutei. Normal anatomic structure is described. Specific disease processes-such as inflammatory lymphadenitis, primary tumors, and vascular diseases-are covered.

  7. Inclusive jet cross-section measurement at CDF

    SciTech Connect

    Norniella, Olga; /Barcelona, IFAE

    2007-05-01

    The CDF Collaboration has measured the inclusive jet cross section using 1992-93 collider data at 1.8 TeV. The CDF measurement is in very good agreement with NLO QCD predictions for transverse energies (E{sub T}) below 200 GeV. However, it is systematically higher than NLO QCD predictions for E{sub T} above 200 GeV.

  8. Cross-section data for selected Puerto Rico streams

    USGS Publications Warehouse

    Colon-Dieppa, Eloy; Gonzalez, Ralph

    1978-01-01

    The data presented are for delineating the inundation which could be expected by floods of selected magnitudes in Puerto Rico. These cross section data can be used in Flood Insurance Administration studies and in other studies related to the planning, development, and management of flood plains. The data were collected by the Caribbean District of the Water Resources Division of the U.S. Geological Survey in cooperation with the Puerto Rico Department of Natural Resources. (Woodard-USGS)

  9. Stellar neutron capture cross sections of the Gd isotopes

    NASA Astrophysics Data System (ADS)

    Wisshak, K.; Voss, F.; Käppeler, F.; Guber, K.; Kazakov, L.; Kornilov, N.; Uhl, M.; Reffo, G.

    1995-11-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? Barium Fluoride Detector, which was improved by replacing crystals with high ? background and by introducing a pierced crystal at zero degrees with respect to the beam axis. These changes resulted in a significantly increased efficiency for capture events. The main experimental problem was that the samples of the two s isotopes 152Gd and 154Gd showed only relatively low enrichment. Nevertheless, the spectroscopic quality of the BaF2 detector allowed evaluation of the corresponding corrections for isotopic impurities reliably. The cross section ratios could be determined with an overall uncertainty of typically 1%, an improvement by factors of five to ten compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 keV and 100 keV. The new stellar cross sections were used for an updated analysis of the s-process reaction flow in the mass region between samarium and gadolinium, which is characterized by branchings at 151Sm, 154Eu, and 155Eu. With the classical approach, the s-process temperature could be constrained corresponding to a range of thermal energies between kT=28 and 33 keV. The 152Gd production in low mass stars was found to depend strongly on the neutron freeze-out at the end of the helium shell burning episodes.

  10. Stellar neutron capture cross sections of the Gd isotopes

    Microsoft Academic Search

    K. Wisshak; F. Voss; F. Käppeler; L. Kazakov; N. Kornilov; G. Reffo

    1995-01-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p,n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4pi Barium Fluoride

  11. Stellar neutron capture cross sections of the Gd isotopes.

    NASA Astrophysics Data System (ADS)

    Wisshak, K.; Voss, F.; Käppeler, F.; Guber, K.; Kazakov, L.; Kornilov, N.; Uhl, M.; Reffo, G.

    1995-05-01

    The neutron capture cross sections of 152Gd, 154Gd, 155Gd, 156Gd, 157Gd, and 158Gd were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li(p, n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? Barium Fluoride Detector The main experimental problem was that the samples of the two s-only isotopes 152Gd and 154Gd showed only relatively low enrichment, but the spectroscopic quality of the BaF2 detector allowed to determine the resulting corrections for isotopic impurities reliably. The cross section ratios could be determined with an overall uncertainty of typically 1%, an improvement by factors of five to ten compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 10 keV and 100 keV. The new stellar cross sections were used for an updated analysis of the s-process reaction flow in the mass region between samarium and gadolinium, which is characterized by branchings at 151Sm, 154Eu, and 155Eu. With the classical approach, the s-process temperature could be constrained corresponding to a range of thermal energies between kT - 28 keV and 33 keV. The 152Gd production in low mass stars was found to depend strongly on the neutron freeze-out at the end of the helium shell burning episodes.

  12. Cross section evaluation in the photodisintegration of152Sm isotope

    NASA Astrophysics Data System (ADS)

    Oprea, C.; Oprea, A.; Mihul, A.

    We have evaluated the cross section of the 152Sm(?, n)151Sm reaction in the frame of the Hauser - Feshbach formalism using the Talys computer codes as well as by using the computer codes written by the authors. The obtained results were compared with experimental data existing in the literature. The named computer codes allowed estimating the necessary penetrability coefficients with no approximations for charged and neutral particles emission in the exit channels.

  13. New Fission Cross Section Measurements using a Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Sadler, Michael

    2008-03-01

    A group of six universities (ACU, California Polytechnic, Colorado School of Mines, Georgia Institute of Technology, Ohio, and Oregon State) and three national laboratories (Los Alamos, Lawrence Livermore, and Idaho) have undertaken the task of building a Time Projection Chamber (TPC) to measure the fission cross sections needed for the next generation of nuclear reactors. The fission TPC concept will be presented, and why we think we can improve on 50 years of fission study.

  14. Preliminary observations of cusp cross-section pinch

    Microsoft Academic Search

    M. A. M. Kashani; T. Miyamoto

    2004-01-01

    Summary form only given. In this paper, we introduce a cusp cross-section pinch (CCSP) as an example of geometrical stabilization, and give the description of constructed device. The CCSP device is, consisted of two sheet Z-pinch devices arranged face to face. Each sheet Z-pinch device is like a coaxial gun, which is elongated to one direction. The plasma sheets are

  15. Measurement of Total Electron Scattering Cross Sections for SO2

    Microsoft Academic Search

    M. E. Johnston; J. A. Berger; J. P. Heggemeier; T. M. Klein

    1999-01-01

    In space sulphur dioxide (SO2) plays an important role in the atmospheres of Jupiter and Venus and interstellar clouds. On Earth it is responsible for acid rain and climate effects. In modeling these systems, electron impact data is needed. In this poster we present absolute total electron impact cross sections from 2 eV to 200 eV. The measurements were made

  16. Factors associated with inflammation markers, a cross-sectional analysis

    Microsoft Academic Search

    Tess V. Clendenen; Karen L. Koenig; Alan A. Arslan; Annekatrin Lukanova; Franco Berrino; Yian Gu; Goran Hallmans; Annika Idahl; Vittorio Krogh; Anna E. Lokshin; Eva Lundin; Paola Muti; Adele Marrangoni; Brian M. Nolen; Nina Ohlson; Roy E. Shore; Sabina Sieri; Anne Zeleniuch-Jacquotte

    Epidemiological studies have reported associations between circulating inflammation markers and risk of chronic diseases. It is of interest to examine whether risk factors for these diseases are associated with inflammation. We conducted a cross-sectional analysis to evaluate whether reproductive and lifestyle factors and circulating vitamin D were associated with inflammation markers, including C-reactive protein, cytokines (IL-1?, IL-2, IL-4, IL-5, IL-6,

  17. Inclusive parton cross sections in photoproduction and photon structure

    Microsoft Academic Search

    T. Ahmed; S. Aid; V. Andreev; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; J. Baehr; Y. Ban; P. Baranov; E. Barrelet; W. Bartel; M. Barth; U. Bassler; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; G. Bernardi; R. Bernet; G. Bertrand-Coremans; M. Besançon; R. Beyer; P. Biddulph; P. Bispham; J. C. Bizot; V. Blobel; K. Borras; F. Botterweck; V. Boudry; A. Braemer; F. Brasse; W. Braunschweig; V. Brisson; D. Bruncko; C. Brune; R. Buchholz; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; M. Burton; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; M. Charlet; D. Clarke; A. B. Clegg; B. Clerbaux; M. Colombo; J. G. Contreras; C. Cormack; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; D. G. Cussans; J. Cvach; S. Dagoret; J. B. Dainton; W. D. Dau; K. Daum; M. David; B. Delcourt; L. Del Buono; A. De Roeck; E. A. De Wolf; P. Di Nezza; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Droutskoi; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; H. Ehrlichmann; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; R. J. Ellison; E. Elsen; M. Erdmann; W. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; J. Ferencei; F. Ferrarotto; K. Flamm; M. Fleischer; M. Flieser; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; E. Gabathuler; K. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; M. Gebauer; A. Gellrich; H. Genzel; R. Gerhards; U. Goerlach; L. Goerlich; N. Gogitidze; M. Goldberg; D. Goldner; B. Gonzalez-Pineiro; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; G. Grindhammer; A. Gruber; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; M. Hampel; E. M. Hanlon; M. Hapke; W. J. Haynes; J. Heatherington; G. Heinzelmann; R. C. W. Henderson; H. Henschel; I. Herynek; M. F. Hess; W. Hildesheim; P. Hill; K. H. Hiller; C. D. Hilton; J. Hladký; K. C. Hoeger; M. Höppner; R. Horisberger; V. L. Hudgson; Ph. Huet; M. Hütte; H. Hufnagel; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; J. Janoth; T. Jansen; L. Jönsson; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; D. Kant; R. Kaschowitz; P. Kasselmann; U. Kathage; J. Katzy; H. H. Kaufmann; S. Kazarian; I. R. Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; J. H. Köhne; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; T. Krämerkämper; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; U. Krüner-Marquis; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; D. Lacour; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; P. Lanius; J.-F. Laporte; A. Lebedev; C. Leverenz; S. Levonian; Ch. Ley; A. Lindner; G. Lindström; J. Link; F. Linsel; J. Lipinski; B. List; G. Lobo; P. Loch; H. Lohmander; J. Lomas; G. C. Lopez; V. Lubimov; D. Lüke; N. Magnussen; E. Malinovski; S. Mani; R. Maracek; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; T. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; A. Migliori; S. Mikocki; D. Milstead; F. Moreau; J. V. Morris; E. Mroczko; G. Müller; K. Müller; P. Murín; V. Nagovizin; R. Nahnhauer; B. Naroska; Th. Naumann; P. R. Newman; D. Newton; D. Neyret; H. K. Nguyen; T. C. Nicholls; F. Niebergall; C. Niebuhr; Ch. Niedzballa; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg-Werther; M. Oakden; H. Oberlack; U. Obrock; J. E. Olsson; D. Ozerov; E. Panaro; A. Panitch; C. Pascaud; G. D. Patel; E. Peppel; E. Perez; J. P. Phillips; Ch. Pichler; A. Pieuchot; D. Pitzl; G. Pope; S. Prell; R. Prosi; K. Rabbertz; G. Rädel; F. Raupach; P. Reimer; S. Reinshagen; P. Ribarics; H. Rick; V. Riech; J. Riedlberger; S. Riess; M. Rietz; E. Rizvi; S. M. Robertson; P. Robmann; H. E. Roloff; R. Roosen; K. Rosenbauer; A. Rostovtsev; F. Rouse; C. Royon; K. Rüter; S. Rusakov; K. Rybicki; R. Rylko; N. Sahlmann; S. G. Salesch; E. Sanchez; D. P. C. Sankey; P. Schacht; S. Schiek; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; G. Schmidt; A. Schöning; V. Schröder; E. Schuhmann; B. Schwab; A. Schwind; F. Sefkow; M. Seidel; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; V. Solochenko; Y. Soloviev; J. Spiekermann; S. Spielman; H. Spitzer; R. Starosta; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; J. Stiewe; U. Stösslein; K. Stolze; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; S. Tapprogge; V. Tchernyshov; C. Thiebaux; G. Thompson; P. Truöl; J. Turnau; J. Tutas; P. Uelkes; A. Usik; S. Valkár; A. Valkárová; C. Vallée; P. Van Esch; P. Van Mechelen

    1995-01-01

    Photoproduction of 2-jet events is studied with the H1 detector at HERA. Parton cross sections are extracted from the data by an unfolding method using leading order parton-jet correlations of a QCD generator. The gluon distribution in the photon is derived in the fractional momentum range 0.04 ? x? ? 1 at the average factorization scale 75 GeV2.

  18. Inclusive charged particle cross sections in photoproduction at HERA

    Microsoft Academic Search

    I. Abt; T. Ahmed; V. Andreev; S. Aid; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; H. Bärwolff; J. Bán; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; G. Bertrand-Coremans; M. Besançon; P. Biddulph; E. Binder; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; A. Braemer; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; J. Chyla; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; J. Cvach; S. Dagoret; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. del Buono; M. Devel; A. de Roeck; P. di Nezza; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; R. Ebbinghaus; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; H. Ehrlichmann; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; I. F. Fensome; J. Ferencei; F. Ferrarotto; K. Flamm; W. Flauger; M. Fleischer; M. Flieser; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; M. Gebauer; A. Gellrich; M. Gennis; H. Genzel; R. Gerhards; L. Godfrey; U. Goerlach; L. Goerlich; N. Gogitidze; M. Goldberg; D. Goldner; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; A. Gruber; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; M. Hampel; E. M. Hanlon; M. Hapke; J. Harjes; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladký; K. C. Hoeger; M. Höppner; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; T. Jansen; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; D. Kant; S. Kazarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; D. Lacour; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; A. Leuschner; C. Leverenz; S. Levonian; D. Lewin; Ch. Ley; A. Lindner; G. Lindström; F. Linsel; J. Lipinski; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; D. Lüke; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfiedl; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; K. Müller; P. Murín; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; P. R. Newman; D. Newton; D. Neyret; H. K. Nguyen; F. Niebergall; C. Niebuhr; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; U. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. P. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; S. Prell; R. Prosi; G. Rädel; F. Raupach; K. Rauschnabel; P. Reimer; S. Reinshagen; P. Ribarics; V. Riech; J. Riedlberger; S. Riess; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; K. Rosenbauer; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; A. Schöning; V. Schröder; E. Schuhmann; M. Schulz; B. Schwab; A. Schwind; W. Scobel; U. Seehausen; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; Y. Soloviev; H. Spitzer; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; U. Stösslein; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; V. Tchernyshov; C. Thiebaux; G. Thompson; I. Tichomirov; P. Truöl; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallée; P. van Esch; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegner; H. P. Wellisch; L. R. West; S. Willard; M. Winde; G.-G. Winter; Th. Wolff; L. A. Womersley

    1994-01-01

    Cross sections are presented for the inclusive production of charged particles measured in electron-proton collisions at low Q2 with the H1 detector at HERA. The transverse momentum distribution extends up to 8 GeV\\/c. Its shape is found to be harder than that observed in pp collisions at comparable centre-of-mass energies &surd;Sgammap ~ &surd;Spp ~ 200GeV, and also harder than in

  19. Retrodeformable cross sections and Oak Ridge fault, Ventura basin, California

    Microsoft Academic Search

    R. S. Yeats; G. F. Huftile

    1988-01-01

    A retrodeformable (balanced) cross section is constructed such that stratified rocks are restored to their undeformed state without loss or gain of bed length or bed thickness. Ductile strata may be area-balanced if original thickness is known. Near Ventura, folds in Pliocene-Pleistocene turbidites and Miocene-early Pliocene shales (Rincon, Monterey, Sisquoc) overlie an unfolded competent Paleogene sequence. The basal decollement of

  20. Calculation of light nucleus reaction cross sections in Geant4

    E-print Network

    V. Uzhinsky

    2012-09-20

    Total reaction cross sections of light projectile nucleus (H-2, H-3, He-3 and He-4) interactions with nuclei are calculated using Geant4 models, and compared with experimental data. It is shown that the models give various predictions at low energies, in the region of the Coulomb barrier. "Shen model" (W.-Q. Shen et al., Nucl. Phys. {\\bf A491} (1989) 130) is identified as an improvement over other models.

  1. Measuring the JPsi-Nucleon dissociation cross section with PANDA

    E-print Network

    Paul Bühler

    2011-09-18

    With the PANDA detector at the HESR at FAIR it will be possible to study the production and absorption of charmed hadrons in nuclear targets. Of special interest in this context is the determination of the JPsi-nucleon dissociation cross section. This can be determined with measurements of the JPsi yield in antiproton-nucleus reactions using different target materials. The experiment is described and numerical simulations are presented.

  2. Reducing cross-sectional data using a genetic algorithm method and effects on cross-section geometry and steady-flow profiles

    USGS Publications Warehouse

    Berenbrock, Charles E.

    2015-01-01

    The effects of reduced cross-sectional data points on steady-flow profiles were also determined. Thirty-five cross sections of the original steady-flow model of the Kootenai River were used. These two methods were tested for all cross sections with each cross section resolution reduced to 10, 20 and 30 data points, that is, six tests were completed for each of the thirty-five cross sections. Generally, differences from the original water-surface elevation were smaller as the number of data points in reduced cross sections increased, but this was not always the case, especially in the braided reach. Differences were smaller for reduced cross sections developed by the genetic algorithm method than the standard algorithm method.

  3. Coherent set of electron cross sections for argon

    NASA Astrophysics Data System (ADS)

    Alves, L. L.; Ferreira, C. M.

    2011-10-01

    This paper presents a coherent set of electron impact cross sections for argon (elastic momentum-transfer, inelastic for the excitation of 37 levels Ar(4s,4p,3d,5p,4d,6s) and ionization), which was recently uploaded onto the LXcat IST-Lisbon database. The cross section set was validated by comparing calculated swarm parameters (electron mobility and characteristic energy) and rate coefficients (Townsend ionization coefficient and direct + cascade excitation coefficients to the 4s and 4p states) with available experimental data, for E / N = 10-4 - 100 Td and Tg = 300, 77 K. The validation procedure involves the solution to the homogeneous two-term electron Boltzmann equation, resorting to three different solvers: (i) IST-Lisbon's (ii) BOLSIG+ (v1.2) with LXcat; (iii) BOLSIG+ (v1.23). The results obtained with these solvers are compared to evidence the importance of certain numerical features related with both the energy-grid (number of points, grid-type and maximum energy value) and the interpolation scheme adopted for the cross sections. In particular, the latter can cause a 6% variation on the values of swarm parameters at intermediate E/Ns.

  4. Summary of the Workshop on Neutron Cross Section Covariances

    SciTech Connect

    Smith, Donald L. [Argonne National Laboratory, 1710 Avenida del Mundo, Coronado, California 92118-3073 (United States)], E-mail: Donald.L.Smith@anl.gov

    2008-12-15

    A Workshop on Neutron Cross Section Covariances was held from June 24-27, 2008, in Port Jefferson, New York. This Workshop was organized by the National Nuclear Data Center, Brookhaven National Laboratory, to provide a forum for reporting on the status of the growing field of neutron cross section covariances for applications and for discussing future directions of the work in this field. The Workshop focused on the following four major topical areas: covariance methodology, recent covariance evaluations, covariance applications, and user perspectives. Attention was given to the entire spectrum of neutron cross section covariance concerns ranging from light nuclei to the actinides, and from the thermal energy region to 20 MeV. The papers presented at this conference explored topics ranging from fundamental nuclear physics concerns to very specific applications in advanced reactor design and nuclear criticality safety. This paper provides a summary of this workshop. Brief comments on the highlights of each Workshop contribution are provided. In addition, a perspective on the achievements and shortcomings of the Workshop as well as on the future direction of research in this field is offered.

  5. Absolute photoionization cross section of the methyl radical.

    PubMed

    Loison, Jean-Christophe

    2010-06-17

    The absolute photoionization cross section of the methyl radical was determined relative to that of NO at photon energies of 10.54 eV using the CH(3) + NO(2) --> CH(3)O + NO reaction. Kinetics of this reaction was studied in a fast flow reactor coupled with VUV laser photoionization. Simulation of the kinetics of the decrease of the methyl signal and the corresponding increase of the NO signal (in combination with the NO absolute photoionization cross section determined by Watanabe (Watanabe, K. J. Chem. Phys. 1954, 22, 1564; Watanabe, K.; Matsunaga, F. M.; Sakai, H. Appl. Opt. 1967, 6, 391)), yields the absolute photoionization cross section of the methyl radical: sigma(CH(3))(10.54 eV) = 5.1 (1.2) x 10(-18) cm(2) (95% confidence interval). This result is in good agreement with the recently published measurements by Taatjes et al. (Taatjes, C. A.; Osborn, D. L.; Selby, T. M.; Meloni, G.; Fan, H.; Pratt, S. T. J. Phys. Chem. A 2008, 112, 9336) and by Gans et al. (Gans, B.; Mendes, L. A. V.; Boyé-Péronne, S.; Douin, S.; Garcia, G.; Soldi-Lose, H.; Cunha de Miranda, B. K.; Alcaraz, C.; Carrasco, N.; Pernot, P.; Gauyacq, D. J. Phys. Chem. A 2009, 114, 3237). PMID:20491459

  6. Activation Cross Sections Improvements needed for IFE Power Reactors Designs

    SciTech Connect

    Rodriguez, A; Cabellos, O; Sanz, J; FalQuina, R; Latkowski, J; Reyes, S

    2003-10-02

    Uncertainties in the prediction of the neutron induced long-lived activity in the natural elements from H to Bi due to activation cross section uncertainties are estimated assuming as neutron environment those of the HYLIFE-II and Sombrero vessel structures. The latest available activation cross section data are employed. The random variables used in the uncertainty analysis have been the concentration limits (CL's) corresponding to hands-on recycling, remote recycling and shallow land burial, quantities typically considered in ranking elements under waste management considerations. The CL standard value (CL{sub nom}), i.e. without uncertainties, is compared with the 95th percentile CL value (CL95). The results of the analysis are very helpful in assessing the quality of the current activation data for IFE applications, providing a rational basis for programmatic priority assignments for new cross sections measurements or evaluations. The HYLIFE-II results shown that a significant error is estimated in predicting the activation of several elements. The estimated errors in the Sombrero case are much less important.

  7. Upscattering Cross Sections for Ultra Cold Neutrons from Gases

    NASA Astrophysics Data System (ADS)

    Seestrom, Susan J.; UCN? Collaboration

    2014-09-01

    The scattering of ultracold neutrons (UCNs) to energies above the escape potential of a trap is called upscattering. Upscattering due to interaction with residual gases is a potential loss mechanism for UCNs stored in a trap that can impact the extracted neutron lifetime. We have developed a method for measuring the cross sections for UCN upscattering from gases stored in a small measurement cell. Upscattered neutrons are measured directly in a 3He ionization chamber and transmitted UCN strike a 10B-coated surface at the edges of the measurement cell. The transmitted UCNs are then counted with a HPGe gamma-ray detector that counts 478 keV ?-rays from the 10B(n , ??) 7Li reaction. The analysis was guided by Monte Carlo descriptions of the LANL UCN source output. We will present cross sections measured for various noble and polyatomic gases, compare these results to calculated cross sections based on models of gas scattering kernels, and use these to estimate the impact of gas upscattering on the measurement of the neutron lifetime.

  8. Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables

    E-print Network

    Dittmaier, S; Passarino, G; Tanaka, R; Baglio, J; Bolzoni, P; Boughezal, R; Brein, O; Collins-Tooth, C; Dawson, S; Dean, S; Denner, A; Farrington, S; Felcini, M; Flechl, M; de Florian, D; Forte, S; Grazzini, M; Hackstein, C; Hahn, T; Harlander, R; Hartonen, T; Heinemeyer, S; Huston, J; Kalinowski, A; Krämer, M; Krauss, F; Lee, J S; Lehti, S; Maltoni, F; Mazumdar, K; Moch, S -O; Mück, A; Mühlleitner, M; Nason, P; Neu, C; Oleari, C; Olsen, J; Palmer, S; Petriello, F; Piacquadio, G; Pilaftsis, A; Potter, C T; Puljak, I; Qian, J; Rebuzzi, D; Reina, L; Rzehak, H; Schumacher, M; Slavich, P; Spira, M; Stöckli, F; Thorne, R S; Acosta, M Vazquez; Vickey, T; Vicini, A; Wackeroth, D; Warsinsky, M; Weber, M; Weiglein, G; Weydert, C; Yu, J; Zaro, M; Zirke, T

    2011-01-01

    This Report summarizes the results of the first 10 months' activities of the LHC Higgs Cross Sections Working Group. The main goal of the working group was to present the status-of-art on Higgs Physics at the LHC integrating all new results that have appeared in the last few years. The Report is more than a mere collection of the proceedings of the general meetings. The subgroups have been working in different directions. An attempt has been made to present the first Report from these subgroups in a complete and homogeneous form. The subgroups' contributions correspondingly comprise the main parts of the Report. A significant amount of work has been performed in providing higher-order corrections to the Higgs-boson cross sections and pinning down the theoretical uncertainty of the Standard Model predictions. This Report comprises explicit numerical results on total cross sections, leaving the issues of event selection cuts and differential distributions to future publications. The subjects for further study a...

  9. Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables

    E-print Network

    LHC Higgs Cross Section Working Group; S. Dittmaier; C. Mariotti; G. Passarino; R. Tanaka; J. Baglio; P. Bolzoni; R. Boughezal; O. Brein; C. Collins-Tooth; S. Dawson; S. Dean; A. Denner; S. Farrington; M. Felcini; M. Flechl; D. de Florian; S. Forte; M. Grazzini; C. Hackstein; T. Hahn; R. Harlander; T. Hartonen; S. Heinemeyer; J. Huston; A. Kalinowski; M. Krämer; F. Krauss; J. S. Lee; S. Lehti; F. Maltoni; K. Mazumdar; S. -O. Moch; A. Mück; M. Mühlleitner; P. Nason; C. Neu; C. Oleari; J. Olsen; S. Palmer; F. Petriello; G. Piacquadio; A. Pilaftsis; C. T. Potter; I. Puljak; J. Qian; D. Rebuzzi; L. Reina; H. Rzehak; M. Schumacher; P. Slavich; M. Spira; F. Stöckli; R. S. Thorne; M. Vazquez Acosta; T. Vickey; A. Vicini; D. Wackeroth; M. Warsinsky; M. Weber; G. Weiglein; C. Weydert; J. Yu; M. Zaro; T. Zirke

    2011-05-20

    This Report summarizes the results of the first 10 months' activities of the LHC Higgs Cross Sections Working Group. The main goal of the working group was to present the status-of-art on Higgs Physics at the LHC integrating all new results that have appeared in the last few years. The Report is more than a mere collection of the proceedings of the general meetings. The subgroups have been working in different directions. An attempt has been made to present the first Report from these subgroups in a complete and homogeneous form. The subgroups' contributions correspondingly comprise the main parts of the Report. A significant amount of work has been performed in providing higher-order corrections to the Higgs-boson cross sections and pinning down the theoretical uncertainty of the Standard Model predictions. This Report comprises explicit numerical results on total cross sections, leaving the issues of event selection cuts and differential distributions to future publications. The subjects for further study are identified.

  10. Three Dimensional Cross-Sectional Properties From Bone Densitometry

    NASA Technical Reports Server (NTRS)

    Cleek, Tammy M.; Whalen, Robert T.; Dalton, Bonnie P. (Technical Monitor)

    2001-01-01

    Bone densitometry has previously been used to obtain cross-sectional properties of bone in a single scan plane. Using three non-coplanar scans, we have extended the method to obtain the principal area Moments of inertia and orientations of the principal axes at each cross-section along the length of the scan. Various 5 aluminum phantoms were used to examine scanner characteristics to develop the highest accuracy possible for in vitro non-invasive analysis of mass distribution. Factors considered included X-ray photon energy, initial scan orientation, the included angle of the 3 scans, and Imin/Imax ratios. Principal moments of inertia were accurate to within 3.1% and principal angles were within 1 deg. of the expected value for phantoms scanned with included angles of 60 deg. and 90 deg. at the higher X-ray photon energy. Low standard deviations in error also 10 indicate high precision of calculated measurements with these included angles. Accuracy and precision decreased slightly when the included angle was reduced to 30 deg. The method was then successfully applied to a pair of excised cadaveric tibiae. The accuracy and insensitivity of the algorithms to cross-sectional shape and changing isotropy (Imin/Imax) values when various included angles are used make this technique viable for future in vivo studies.

  11. Status of Nuclear Physics Cross Sections Models and Future Directions

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; Tripathi, Ram; Kim, Myung-Hee Y.

    2012-07-01

    Exposures from the hazards of space radiation in deep space/long duration missions are very different from that of low earth orbit, and much needs to be learned about their effects. The overall situation is further augmented by the nonexistence of in vivo or in vitro data or studies about continuous long duration tissues exposure to radiation and concomitant biological uncertainties. All radiation protection and shielding transport and needed nuclear cross sections models so far have focused on radiation that goes through the shielding materials and are usually high energy physics models. From the perspective of exposure to astronauts, this exposure contributes to health risks. However, the very important radiation exposure where the radiation traverses through the astronauts and considerably slows down and/or even stops inside their body is less well studied. This kind of radiation contributes may be more biologically damaging than the radiation which just passes through because the ionizing power is highest as the particle stops in tissue. There is a clear need for improved nuclear physics cross sections models to described low energy collisions. Low energy physics significantly contributes to biological dose, risk assessments, and related uncertainty evaluations. In this report we will focus on the current status of these (mostly low energy) cross sections models and elaborate on future directions.

  12. Radar reflection off extensive air showers

    E-print Network

    Stasielak, J; Bertaina, M; Blümer, J; Chiavassa, A; Engel, R; Haungs, A; Huege, T; Kampert, K -H; Klages, H; Kleifges, M; Krömer, O; Ludwig, M; Mathys, S; Neunteufel, P; Pekala, J; Rautenberg, J; Riegel, M; Roth, M; Salamida, F; Schieler, H; Šmída, R; Unger, M; Weber, M; Werner, F; Wilczy?ski, H; Wochele, J

    2012-01-01

    We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.

  13. Quantum Mechanical Determination of Rotational Energy Transfer Cross Sections.

    NASA Astrophysics Data System (ADS)

    Borer, William Shepherd

    Studies of the quantum mechanical determination of rotationally inelastic molecular collision rates are reported. A unified derivation of the coupled equations of scattering is given for four different quantum mechanical approximations. A new method for integrating the resulting coupled equations is studied and tested on a realistic potential surface. This method differs from conventional methods by not requiring the construction of a complete set of solutions to the second order differential equations in order to form a single solution satisfying the scattering boundary conditions. The method requires a computational effort proportional only to the square of the number of coupled equations as opposed to the cube which is characteristic of the conventional methods. In its primitive form, we find that the method is susceptible to several sources of numerical instability and does not always converge. Solutions to these problems are presented and discussed. A new bound on the error incurred through numerical integration of the coupled scattering equations is studied and applied to a model elastic potential. An optimal grid is found that minimizes the error measured by this bound. An improvement to the measure which weights more heavily those areas of the integration region for which the values of physical observables are expected to be more sensitive is made and studied. S matrix elements needed to exactly compute cross sections for angular momentum transfer in collisions between argon and hydrogen chloride have been computed using the studied method. Cross sections were constructed by forming the appropriate superpositions of computed S matrix elements. Cross sections for the width and shift of the j = 0 to 1 and j = 5 to 6 pure rotational absorption lines of HCl perturbed by Ar were computed at four different energies. The quantum mechanical cross sections agree well with previously computed counterparts obtained through a semiclassical treatment of the dynamics on the same potential surface as well as with experimental measurements on the same system. State to state cross sections between individual rotor states labelled by j and m where m is the quantum number for projection along a specified axis were also calculated. A distinct propensity to conserve m in inelastic collisions was found for one particular choice of quantization axis. This propensity is related to features of the potential surface and is consistent with similar propensities found in other molecular systems.

  14. From ZZ to ZH : How Low Can These Cross Sections Go or Everybody, Let's Cross Section Limbo!

    SciTech Connect

    Strauss, Emanuel Alexandre; /SUNY, Stony Brook

    2009-08-01

    We report on two searches performed at the D0 detector at the Fermi National Laboratory. The first is a search for Z di-boson production with a theoretical cross section of 1.4 pb. The search was performed on 2.6 fb{sup -1} of data and contributed to the first observation of ZZ production at a hadron collider. The second is a search for a low mass Standard Model Higgs in 4.2 fb{sup -1} of data. The Higgs boson is produced in association with a Z boson where the Higgs decays hadronically and the Z decays to two leptons. The ZZ search was performed in both the di-electron and di-muon channels. For the ZH search, we will focus on the muonic decays where we expanded the traditional coverage by considering events in which one of the two muons fails the selection requirement, and is instead reconstructed as an isolated track. We consider Higgs masses between 100 and 150 GeV, with theoretical cross sections ranging from 0.17 to 0.042 pb, and set upper limits on the ZH production cross-section at 95% confidence level.

  15. Handbook of LHC Higgs Cross Sections: 3. Higgs Properties Report of the LHC Higgs Cross Section Working Group

    E-print Network

    Mariotti, C; Passarino, G; Tanaka, R; Andersen, J R; Artoisenet, P; Bagnaschi, E A; Banfi, A; Becher, T; Bernlochner, F U; Bolognesi, S; Bolzoni, P; Boughezal, R; Buarque, D; Campbell, J; Caola, F; Carena, M; Cascioli, F; Chanon, N; Cheng, T; Choi, S Y; David, A; de Aquino, P; Degrassi, G; Del Re, D; Denner, A; van Deurzen, H; Diglio, S; Di Micco, B; Di Nardo, R; Dittmaier, S; Dührssen, M; Ellis, R K; Ferrera, G; Fidanza, N; Flechl, M; de Florian, D; Forte, S; Frederix, R; Frixione, S; Gangal, S; Gao, Y; Garzelli, M V; Gillberg, D; Govoni, P; Grazzini, M; Greiner, N; Griffiths, J; Gritsan, A V; Grojean, C; Hall, D C; Hays, C; Harlander, R; Hernandez-Pinto, R; Höche, S; Huston, J; Jubb, T; Kadastik, M; Kallweit, S; Kardos, A; Kashif, L; Kauer, N; Kim, H; Klees, R; Krämer, M; Krauss, F; Laureys, A; Laurila, S; Lehti, S; Li, Q; Liebler, S; Liu, X; Logan, E; Luisoni, G; Malberti, M; Maltoni, F; Mawatari, K; Maierhoefer, F; Mantler, H; Martin, S; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mellado, B; Melnikov, K; Meridiani, P; Miller, D J; Mirabella, E; Moch, S O; Monni, P; Moretti, N; Mück, A; Mühlleitner, M; Musella, P; Nason, P; Neu, C; Neubert, M; Oleari, C; Olsen, J; Ossola, G; Peraro, T; Peters, K; Petriello, F; Piacquadio, G; Potter, C T; Pozzorini, S; Prokofiev, K; Puljak, I; Rauch, M; Rebuzzi, D; Reina, L; Rietkerk, R; Rizzi, A; Rotstein-Habarnau, Y; Salam, G P; Sborlini, G; Schissler, F; Schönherr, M; Schulze, M; Schumacher, M; Siegert, F; Slavich, P; Smillie, J M; Stål, O; von Soden-Fraunhofen, J F; Spira, M; Stewart, I W; Tackmann, F J; Taylor, P T E; Tommasini, D; Thompson, J; Thorne, R S; Torrielli, P; Tramontano, F; Tran, N V; Trócsányi, Z; Ubiali, M; Vazquez Acosta, M; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Wagner, C; Walsh, J R; Wang, J; Weiglein, G; Whitbeck, A; Williams, C; Yu, J; Zanderighi, G; Zanetti, M; Zaro, M; Zerwas, P M; Zhang, C; Zirke, T J E; Zuberi, S

    2013-01-01

    This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered p...

  16. Radioactive targets for neutron-induced cross section measurements

    SciTech Connect

    Kronenberg, A. (Andreas); Bond, E. M. (Evelyn M.); Glover, S. E. (Samuel E.); Rundberg, R. S. (Robert S.); Vieira, D. J. (David J.); Esch, E. I. (Ernst-Ingo); Reifarth, R. (Rene); Ullmann, J. L. (John L.); Haight, Robert C.; Rochmann, D. (Dimitri)

    2004-01-01

    Measurements using radioactive targets are important for the determination of key reaction path ways associated with the synthesis of the elements in nuclear astrophysics (sprocess), advanced fuel cycle initiative (transmutation of radioactive waste), and stockpile stewardship. High precision capture cross-section measurements are needed to interpret observations, predict elemental or isotopical ratios, and unobserved abundances. There are two new detector systems that are presently being commissioned at Los Alamos National Laboratory for very precise measurements of (n,{gamma}) and (n,f) cross-sections using small quantities of radioactive samples. DANCE (Detector for Advanced Neutron-Capture Experiments), a 4 {pi} gamma array made up of 160 BaF{sub 2} detectors, is designed to measure neutron capture cross-sections of unstable nuclei in the low-energy range (thermal to {approx}500 keV). The high granularity and high detection efficiency of DANCE, combined with the high TOF-neutron flux available at the Lujan Center provides a versatile tool for measuring many important cross section data using radioactive and isotopically enriched targets of about 1 milligram. Another powerful instrument is the Lead-slowing down spectrometer (LSDS), which will enable the measurement of neutron-induced fission cross-section of U-235m and other short-lived actinides in a energy range from 1-200 keV with sample sizes down to 10 nanograms. Due to the short half-life of the U-235m isomer (T{sub 1/2} = 26 minutes), the samples must be rapidly and repeatedly extracted from its {sup 239}Pu parent. Since {sup 239}Pu is itself highly fissile, the separation must not only be rapid, but must also be of very high purity (the Pu must be removed from the U with a decontamination factor >10{sup 12}). Once extracted and purified, the {sup 235m}U isomer would be electrodeposited on solar cells as a fission detector and placed within the LSDS for direct (n,f) cross section measurements. The production of radioactive targets of a few milligrams will be described as well as the containment for safe handling of these targets at the Lujan Center at LANSCE. To avoid any contamination, the targets are electrochemically fixed onto thin Ti foils and two foils are placed back to back to contain the radioactive material within. This target sandwich is placed in a cylinder made of aluminum with thin translucent windows made of Kapton. Actinides targets, such as {sup 234,235,236,238}U, {sup 237}Np, and {sup 239}Pu are prepared by electrodeposition or molecular plating techniques. Target thicknesses of 1-2 mg/cm{sup 2} with sizes of 1 cm{sup 2} or more have been made. Other targets will be fabricated from separation of irradiated isotopically enriched targets, such as {sup 155}Eu from {sup 154}Sm,{sup 171}Tm from {sup 170}Er, and {sup 147}Pm from {sup 146}Nd, which has been irradiated in the high flux reactor at ILL, Grenoble. A radioactive sample isotope separator (RSIS) is in the process of being commissioned for the preparation of other radioactive targets. A brief summary of these experiments and the radioactive target preparation technique will be given.

  17. Detailed photonuclear cross-section calculations and astrophysical applications

    SciTech Connect

    Gardner, D.G.; Gardner, M.A.; Hoff, R.W.

    1989-06-15

    We have investigated the role of an isomeric state and its coupling to the ground state (g.s.) via photons and neutron inelastic scattering in a stellar environment by making detailed photonuclear and neutron cross-section calculations for /sup 176/Lu and /sup 210/Bi. In the case of /sup 176/Lu, the g.s. would function as an excellent galactic slow- (s-) process chronometer were it not for the 3.7-h isomer at 123 keV. Our calculations predicted much larger photon cross sections for production of the isomer, as well as a lower threshold, than had been assumed based on earlier measurements. These two factors combine to indicate that an enormous correction, a factor of 10/sup 7/, must be applied to shorten the current estimate of the half-life against photoexcitation of /sup 176/Lu as a function of temperature. This severely limits the use of /sup 176/Lu as a stellar chronometer and indicates a significantly lower temperature at which the two states reach thermal equilibrium. For /sup 210/Bi, our preliminary calculations of the production and destruction of the 3 /times/ 10/sup 6/ y isomeric state by neutrons and photons suggest that the /sup 210/Bi isomer may not be destroyed by photons as rapidly as assumed in certain stellar environments. This leads to an alternate production path of /sup 207/Pb and significantly affects presently interpreted lead isotopic abundances. We have been able to make such detailed nuclear cross-section calculations using: modern statistical-model codes of the Hauser-Feshbach type, with complete conservation of angular momentum and parity; reliable systematics of the input parameters required by these codes, including knowledge of the absolute gamma-ray strength-functions for E1, M1, and E2 transitions; and codes developed to compute large, discrete, nuclear level sets, their associated gamma-ray branchings, and the presence and location of isomeric states. 7 refs., 2 figs.

  18. Propionaldehyde infrared cross-sections and band strengths

    NASA Astrophysics Data System (ADS)

    Köro?lu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.

    2015-02-01

    The use of oxygenated biofuels reduces the greenhouse gas emissions; however, they also result in increased toxic aldehyde by-products, mainly formaldehyde, acetaldehyde, acrolein, and propionaldehyde. These aldehydes are carcinogenic and/or toxic and therefore it is important to understand their formation and destruction pathways in combustion and atmospheric systems. Accurate information about their infrared cross-sections and integrated strengths are crucially needed for development of quantitative detection schemes and modeling tools. Critical to the development of such diagnostics are accurate characterization of the absorption features of these species. In this study, the gas phase infrared spectra of propionaldehyde (also called propanal, CH3-CH2-CHO), a saturated three carbon aldehyde found in the exhaust emissions of biodiesel or diesel fuels, was studied using high resolution Fourier Transform Infrared (FTIR) spectroscopy over the wavenumber range of 750-3300 cm-1 and at room temperature 295 K. The absorption cross sections of propionaldehyde were recorded at resolutions of 0.08 and 0.096 cm-1 and at seven different pressures (4-33 Torr). The calculated band-strengths were reported and the integrated band intensity results were compared with values taken from the Pacific Northwest National Laboratory (PNNL) database (showing less than 2% discrepancy). The peak positions of the 19 different vibrational bands of propionaldehyde were also compared with previous studies taken at a lower resolution of 1 cm-1. To the best of our knowledge, the current FTIR measurements provide the first highest resolution infrared cross section data for propionaldehyde.

  19. Hadronic Production of psi(2S) Cross section and Polarization

    SciTech Connect

    Chung, Kwangzoo; /Carnegie Mellon U.

    2008-05-01

    The hadronic production cross section and the polarization of {psi}(2S) meson are measured by using the data from p{bar p} collisions at {radical}s = 1.96 TeV collected by the Collider Detector at Fermilab. The datasets used correspond to integrated luminosity of 1.1 fb{sup -1} and 800 pb{sup -1}, respectively. The decay {psi}(2S) {yields} {mu}{sup +}{mu}{sup -} is used to reconstruct {psi}(2S) mesons in the rapidity range |y({psi}(2S))| < 0.6. The coverage of the p{sub T} range is 2.0 GeV/c {le} p{sub T} ({psi}(2S)) < 30 GeV/c for the cross section analysis and pT {ge} 5 GeV/c for the polarization analysis. For events with p{sub T} ({psi}(2S)) > 2 GeV/c the integrated inclusive cross section multiplied by the branching ratio for dimuon decay is 3.17 {+-} 0.04 {+-} 0.28 nb . This result agrees with the CDF Run I measurement considering the increased center-of-mass energy from 1.8 TeV to 1.96 TeV. The polarization of the promptly produced {psi}(2S) mesons is found to be increasingly longitudinal as p{sub T} increases from 5 GeV/c to 30 GeV/c. The result is compared to contemporary theory models.

  20. MOX Cross-Section Libraries for ORIGEN-ARP

    SciTech Connect

    Gauld, I.C.

    2003-07-01

    The use of mixed-oxide (MOX) fuel in commercial nuclear power reactors operated in Europe has expanded rapidly over the past decade. The predicted characteristics of MOX fuel such as the nuclide inventories, thermal power from decay heat, and radiation sources are required for design and safety evaluations, and can provide valuable information for non-destructive safeguards verification activities. This report describes the development of computational methods and cross-section libraries suitable for the analysis of irradiated MOX fuel with the widely-used and recognized ORIGEN-ARP isotope generation and depletion code of the SCALE (Standardized Computer Analyses for Licensing Evaluation) code system. The MOX libraries are designed to be used with the Automatic Rapid Processing (ARP) module of SCALE that interpolates appropriate values of the cross sections from a database of parameterized cross-section libraries to create a problem-dependent library for the burnup analysis. The methods in ORIGEN-ARP, originally designed for uranium-based fuels only, have been significantly upgraded to handle the larger number of interpolation parameters associated with MOX fuels. The new methods have been incorporated in a new version of the ARP code that can generate libraries for low-enriched uranium (LEU) and MOX fuel types. The MOX data libraries and interpolation algorithms in ORIGEN-ARP have been verified using a database of declared isotopic concentrations for 1042 European MOX fuel assemblies. The methods and data are validated using a numerical MOX fuel benchmark established by the Organization for Economic Cooperation and Development (OECD) Working Group on burnup credit and nuclide assay measurements for irradiated MOX fuel performed as part of the Belgonucleaire ARIANE International Program.

  1. Constant cross section of loops in the solar corona

    NASA Astrophysics Data System (ADS)

    Peter, H.; Bingert, S.

    2012-12-01

    Context. The corona of the Sun is dominated by emission from loop-like structures. When observed in X-ray or extreme ultraviolet emission, these million K hot coronal loops show a more or less constant cross section. Aims: In this study we show how the interplay of heating, radiative cooling, and heat conduction in an expanding magnetic structure can explain the observed constant cross section. Methods: We employ a three-dimensional magnetohydrodynamics (3D MHD) model of the corona. The heating of the coronal plasma is the result of braiding of the magnetic field lines through footpoint motions and subsequent dissipation of the induced currents. From the model we synthesize the coronal emission, which is directly comparable to observations from, e.g., the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (AIA/SDO). Results: We find that the synthesized observation of a coronal loop seen in the 3D data cube does match actually observed loops in count rate and that the cross section is roughly constant, as observed. The magnetic field in the loop is expanding and the plasma density is concentrated in this expanding loop; however, the temperature is not constant perpendicular to the plasma loop. The higher temperature in the upper outer parts of the loop is so high that this part of the loop is outside the contribution function of the respective emission line(s). In effect, the upper part of the plasma loop is not bright and thus the loop actually seen in coronal emission appears to have a constant width. Conclusions: From this we can conclude that the underlying field-line-braiding heating mechanism provides the proper spatial and temporal distribution of the energy input into the corona - at least on the observable scales. Movies associated to Figs. 1 and 2 are available in electronic form at http://www.aanda.org

  2. Resolution function of nonsinusoidal radar signals. I - Range-velocity resolution with rectangular pulses

    Microsoft Academic Search

    Nasser J. Mohamed

    1990-01-01

    A generalization of a previously published ambiguity function that applies to radar known as large-relative-bandwidth radar, carrier-free radar, impulse radar, or nonsinusoidal radar is discussed. This radar has recently attracted attention because of its ability to penetrate absorbing materials used in the stealth technology. Another good application is the detection of moving targets with a small radar cross section by

  3. Resolution function of nonsinusoidal radar signals. I. Range-velocity resolution with rectangular pulses

    Microsoft Academic Search

    N. J. Mohamed

    1990-01-01

    A generalization of a previously published ambiguity function that applies to radar known as large-relative-bandwidth radar, carrier-free radar, impulse radar, or nonsinusoidal radar is discussed. This radar has attracted attention because of its ability to penetrate absorbing materials used in the stealth technology. Another good application is the detection of moving targets with a small radar cross section by a

  4. Photon plus Jet Cross Sections at the Tevatron

    E-print Network

    Lars Sonnenschein

    2008-04-03

    Photon plus jet production has been studied by the D0 and CDF experiments in Run II of the Fermilab Tevatron Collider at a center of mass energy of sqrt{s}=1.96 TeV. Measurements of the inclusive photon plus jet, di-photon and photon plus b jet cross section are presented. They are based on integrated luminosities between 0.2 fb^-1 and 1.1 fb^-1. The results are compared to perturbative QCD calculations in various approximations.

  5. Direct (. pi. /sup +/,pd) cross sections for light nuclei

    SciTech Connect

    Yokota, H.; Igarashi, S.; Hama, K.; Mori, T.; Katsumi, T.; Nakayama, K.; Ichimaru, K.; Chiba, R.; Nakai, K.; Chiba, J.; and others

    1989-05-01

    The angular distributions of the inclusive (..pi../sup +/,pd) cross section were measured for /sup 6/Li, /sup 7/Li, and C at T/sub ..pi../ = 70, 130, and 165 MeV over a wide angular range. They were found very similar to that of the ..pi..+/sup 3/H(/sup 3/He)..-->..N+d reaction at the low-momentum-transfer region, especially for Li isotopes. However, at the higher-momentum-transfer region, slight peaks which were not expected in the ..pi..+/sup 3/H(/sup 3/He)..-->..N+d were observed.

  6. Measurement of fusion cross sections for 16O+16O

    NASA Astrophysics Data System (ADS)

    Duarte, J. G.; Gasques, L. R.; Oliveira, J. R. B.; Zagatto, V. A. B.; Chamon, L. C.; Medina, N. H.; Added, N.; Seale, W. A.; Alcántara-Núñez, J. A.; Rossi, E. S., Jr.; Amador-Valenzuela, P.; Lépine-Szily, A.; Freitas, A. S.; Scarduelli, V.; Aguiar, V. A. P.; Shorto, J. M. B.

    2015-06-01

    In earlier works, the fusion cross section for the 16O+16O reaction has been measured using different techniques. In the present work, we have obtained an experimental excitation function for 16O+16O using ?-ray spectroscopy. The measurements were performed at center-of-mass energies between 8.28 and 12.25 MeV. The theoretical predictions obtained with a coupled-channel model are consistent with the experimental data. From our analyses, the extrapolated S-factor value at 6.6 MeV, corresponding to the Gamow peak energy for core oxygen burning conditions, is about 3.6 × 1025 MeV barn.

  7. Diffractive cross sections and event final states at the LHC

    E-print Network

    Goulianos, Konstantin

    2010-01-01

    We discuss a phenomenological model that describes results on diffractive pp and pbar-p cross sections and event final states up to the Fermilab Tevatron collider energy of 1.96 TeV and use it to make predictions for Large Hadron Collider (LHC) collision energies up to 14 TeV and asymptotically as the pp collision energy goes to infinity. The model is anchored in a saturation effect observed in single diffraction dissociation that explains quantitatively the factorization breaking observed in soft and hard pp and pbar-p diffractive processes and in diffractive photoproduction and low Q-square deep inelastic scattering.

  8. SCALE system cross-section validation for criticality safety analysis

    SciTech Connect

    Hathout, A.M.; Westfall, R.M.; Dodds, H.L. Jr.

    1980-01-01

    The purpose of this study is to test selected data from three cross-section libraries for use in the criticality safety analysis of UO/sub 2/ fuel rod lattices. The libraries, which are distributed with the SCALE system, are used to analyze potential criticality problems which could arise in the industrial fuel cycle for PWR and BWR reactors. Fuel lattice criticality problems could occur in pool storage, dry storage with accidental moderation, shearing and dissolution of irradiated elements, and in fuel transport and storage due to inadequate packing and shipping cask design. The data were tested by using the SCALE system to analyze 25 recently performed critical experiments.

  9. Fabrication and characterization of silicon nanowires with triangular cross section

    NASA Astrophysics Data System (ADS)

    Pennelli, Giovanni; Piotto, Massimo

    2006-09-01

    Fabrication processes for silicon nanowires with triangular cross section are presented. Processes based on high resolution electron beam lithography and anisotropic etching have been developed on silicon on insulator substrates. As shown by numerical simulations, the triangular shape of the wire allows strong reduction of the dimensions by successive oxidation steps. Moreover, it is easy to define a gate on top of the wire that wraps the device and, with the back gate silicon substrate, allows the biasing of the structure on all sides. The conduction through the wire, as a function of the gate bias and for different temperatures, is reported and discussed.

  10. Testing Weak Cross-Sectional Dependence in Large Panels

    E-print Network

    Pesaran, M. Hashem

    2012-02-28

    of weak-cross-sectional dependence, and in particular determine the range of values of #11; for which the test has power. 18 References [1] Anselin, L. (1988), Spatial Econometrics: Methods and Models, Dorddrecht: Kluwer Academic Publishers. [2] Anselin, L... of Cambridge Working Papers in Economics 1206, Faculty of Economics, University of Cambridge. [4] Baltagi, B. Q. Feng, and Kao, C. (2011), "Testing for Sphericity in a Fixed E¤ects Panel Data Model. The Econometrics Journal 14, 25-47. [5] Breusch, T...

  11. Neutron cross section standards evaluations for ENDF/B-VI

    SciTech Connect

    Carlson, A.D.; Poenitz, W.P.; Hale, G.M.; Peelle, R.W.

    1985-01-01

    The neutron cross section standards are now being evaluated as the initial phase in the development of the new ENDF/B-VI file. These standards evaluations are following a somewhat different process compared with that used for earlier versions of ENDF. The primary effort is concentrated on a simultaneous evaluation using a generalized least squares program, R-matrix evaluations, and a procedure for combining the results of these evaluations. The ENDF/B-VI standards evaluation procedure is outlined, and preliminary simultaneous evaluation and R-matrix results are presented. 16 refs., 7 figs.

  12. Predictive model of nucleon-nucleus scattering cross sections

    SciTech Connect

    Amos, K. (Ken); Deb, P. (Pradip); Karataglidis, S. (Steven); Madland, D. G.

    2001-01-01

    Nucleon total reaction and neutron total cross sections as well as differential (including spin) observables from 25 to 300 MeV for stable nuclei from 6Li to 238U have been predicted that are in good agreement with measured data. Those predictions have been made using non-local, energy dependent, and complex optical potentials in coordinate space formed by full folding of effective nucleon-nucleon interactions with realistic nuclear ground state densities. By inverse kinematics the same model prescription describes exotic (radioactive) nuclei scattering from hydrogen as a target and the results reveal the extended (neutron) distributions such nuclei can have.

  13. 3He Spin-Dependent Cross Sections and Sum Rules

    SciTech Connect

    Slifer, Karl; Amaryan, Moscov; Amaryan, Moskov; Auerbach, Leonard; Averett, Todd; Berthot, J.; Bertin, Pierre; Bertozzi, William; Black, Tim; Brash, Edward; Brown, D.; Burtin, Etienne; Calarco, John; Cates, Gordon; Chai, Zhengwei; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Ciofi, Claudio; Cisbani, Evaristo; De Jager, Cornelis; Deur, Alexandre; DiSalvo, R.; Dieterich, Sonja; Djawotho, Pibero; Finn, John; Fissum, Kevin; Fonvieille, Helene; Frullani, Salvatore; Gao, Haiyan; Gao, Juncai; Garibaldi, Franco; Gasparian, Ashot; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Glashausser, Charles; Glockle, W.; Golak, J.; Goldberg, Emma; Gomez, Javier; Gorbenko, Viktor; Hansen, Jens-Ole; Hersman, F.; Holmes, Richard; Huber, Garth; Hughes, Emlyn; Humensky, Thomas; Incerti, Sebastien; Iodice, Mauro; Jensen, S.; Jiang, Xiaodong; Jones, C.; Jones, G.; Jones, Mark; Jutier, Christophe; Kamada, H.; Ketikyan, Armen; Kominis, Ioannis; Korsch, Wolfgang; Kramer, Kevin; Kumar, Krishna; Kumbartzki, Gerfried; Kuss, Michael; Lakuriqi, Enkeleida; Laveissiere, Geraud; LeRose, John; Liang, Meihua; Liyanage, Nilanga; Lolos, George; Malov, Sergey; Marroncle, Jacques; McCormick, Kathy; McKeown, Robert; Meziani, Zein-Eddine; Michaels, Robert; Mitchell, Joseph; Nogga, Andreas; Pace, Emanuele; Papandreou, Zisis; Pavlin, Tina; Petratos, Gerassimos; Pripstein, David; Prout, David; Ransome, Ronald; Roblin, Yves; Rowntree, David; Rvachev, Marat; Sabatie, Franck; Saha, Arunava; Salme, Giovanni; SCOPETTA, S.; Skibinski, R.; Souder, Paul; Saito, Teijiro; Strauch, Steffen; Suleiman, Riad; Takahashi, Kazunori; Todor, Luminita; Tsubota, Hiroaki; Ueno, Hiroaki; Urciuoli, Guido; van der Meer, Rob; Vernin, Pascal; Voskanyan, Hakob; Witala, Henryk; Wojtsekhowski, Bogdan; Xiong, Feng; Xu, Wang; Yang, Jae-Choon; Zhang, Bin; Zolnierczuk, Piotr

    2008-07-01

    We present a measurement of the spin-dependent cross sections for the \\vec{^3He}(\\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse approximation and exact three-body Faddeev calculations are also compared to the data in the quasielastic region.

  14. 3He Spin-Dependent Cross Sections and Sum Rules

    E-print Network

    E94010 Collaboration; K. Slifer; M. Amarian; L. Auerbach; T. Averett; J. Berthot; P. Bertin; B. Bertozzi; T. Black; E. Brash; D. Brown; E. Burtin; J. Calarco; G. Cates; Z. Chai; J. -P. Chen; Seonho Choi; E. Chudakov; C. Ciofi degli Atti; E. Cisbani; C. W. de Jager; A. Deur; R. DiSalvo; S. Dieterich; P. Djawotho; M. Finn; K. Fissum; H. Fonvieille; S. Frullani; H. Gao; J. Gao; F. Garibaldi; A. Gasparian; S. Gilad; R. Gilman; A. Glamazdin; C. Glashausser; W. Glockle; J. Golak; E. Goldberg; J. Gomez; V. Gorbenko; J. -O. Hansen; B. Hersman; R. Holmes; G. M. Huber; E. Hughes; B. Humensky; S. Incerti; M. Iodice; S. Jensen; X. Jiang; C. Jones; G. Jones; M. Jones; C. Jutier; H. Kamada; A. Ketikyan; I. Kominis; W. Korsch; K. Kramer; K. Kumar; G. Kumbartzki; M. Kuss; E. Lakuriqi; G. Laveissiere; J. J. Lerose; M. Liang; N. Liyanage; G. Lolos; S. Malov; J. Marroncle; K. McCormick; R. D. McKeown; Z. -E. Meziani; R. Michaels; J. Mitchell; A. Nogga; E. Pace; Z. Papandreou; T. Pavlin; G. G. Petratos; D. Pripstein; D. Prout; R. Ransome; Y. Roblin; D. Rowntree; M. Rvachev; F. Sabatie; A. Saha; G. Salme; S. Scopetta; R. Skibinski; P. Souder; T. Saito; S. Strauch; R. Suleiman; K. Takahashi; S. Teijiro; L. Todor; H. Tsubota; H. Ueno; G. Urciuoli; R. Van der Meer; P. Vernin; H. Voskanian; H. Witala; B. Wojtsekhowski; F. Xiong; W. Xu; J. -C. Yang; B. Zhang; P. Zolnierczuk

    2008-07-11

    We present a measurement of the spin-dependent cross sections for the \\vec{^3He}(\\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse approximation and exact three-body Faddeev calculations are also compared to the data in the quasielastic region.

  15. Status of multigroup cross-section data for shielding applications

    SciTech Connect

    Roussin, R.W.; Maskewitz, B.F.; Trubey, D.K.

    1983-01-01

    Multigroup cross-section libraries for shielding applications in formats for direct use in discrete ordinates or Monte Carlo codes have long been a part of the Data Library Collection (DLC) of the Radiation Shielding Information Center (RSIC). In recent years libraries in more flexible and comprehensive formats, which allow the user to derive his own problem-dependent sets, have been added to the collection. The current status of both types is described, as well as projections for adding data libraries based on ENDF/B-V.

  16. Cross sections and reaction rates of relevance to aeronomy

    SciTech Connect

    Fox, J.L. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    Experimental and theoretical data relevant to models and measurements of the chemical and thermal structures and luminosity of the thermospheres of the earth and planets published during the last four years are surveyed. Among chemical processes, attention is given to ion-molecule reactions, dissociative recombination of molecular ions, and reactions between neutral species. Both reactions between ground state species and species in excited states are considered, including energy transfer and quenching. Measured and calculated cross sections for interactions of solar radiation with atmospheric species, such as photoabsorption, photoionization, and photodissociation and related processes are surveyed.

  17. Toward multi-differential cross sections: measuring two angularities on a single jet

    E-print Network

    Larkoski, Andrew James

    The analytic study of differential cross sections in QCD has typically focused on individual observables, such as mass or thrust, to great success. Here, we present a first study of double differential jet cross sections ...

  18. Activation cross sections, isomeric cross-section ratios and systematics of (n, 2n) reactions at 14-15 MeV

    Microsoft Academic Search

    S. M. Qaim

    1972-01-01

    Total cross sections for eighteen (n, 2n) reactions at 14.7 +\\/- 0.3 MeV in the medium- and heavymass regions have been measured by the activation technique using Ge(Li) detector gamma-ray spectroscopy. Isomeric (n, 2n) cross-section ratios were determined for 54Fe, 92Mo, 191Ir, 198Pt and 198Hg. A comparison of the experimental cross-section values with theoretical estimates based on the statistical model

  19. Advanced Neutron Source Cross Section Libraries (ANSL-V): ENDF\\/BV based multigroup cross-section libraries for advanced neutron source (ANS) reactor studies

    Microsoft Academic Search

    W. E. Ford; J. W. Arwood; N. M. Greene; D. L. Moses; L. M. Petrie; R. T. Primm; C. O. Slater; R. M. Westfall; R. Q. Wright

    1990-01-01

    Pseudo-problem-independent, multigroup cross-section libraries were generated to support Advanced Neutron Source (ANS) Reactor design studies. The ANS is a proposed reactor which would be fueled with highly enriched uranium and cooled with heavy water. The libraries, designated ANSL-V (Advanced Neutron Source Cross Section Libraries based on ENDF\\/B-V), are data bases in AMPX master format for subsequent generation of problem-dependent cross-sections

  20. Radar proves its worth in dam rehabilitation

    SciTech Connect

    NONE

    1996-08-01

    This article outlines the use of radar techniques to survey the masonry structure of White Marble Dam. The survey used a subsurface interface radar, and this equipment displayed a cross-sectional profile of the entire structure, revealing the size and location of any faults. By avoiding the draining and dredging of the upstream pool, it is estimated that this technique saved three months.