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1

On the radar cross section (RCS) prediction of vehicles moving on the ground  

NASA Astrophysics Data System (ADS)

As readers should be aware, Radar Cross Section depends on the factors such as: Wave frequency and polarization, Target dimension, angle of ray incidence, Target's material and covering, Type of radar system as monostatic or bistatic, space in which contains target and propagating waves, and etc. Having moved or stationed in vehicles can be effective in RCS values. Here, we investigate effective factors in RCS of moving targets on the ground or sea. Image theory in electromagnetic applies to be taken into account RCS of a target over the ground or sea.

Sabihi, Ahmad

2014-12-01

2

An investigation of the RCS (radar cross section) computation of grid cavities  

NASA Astrophysics Data System (ADS)

In this paper, the aperture of a cavity is covered by a metallic grid net. This metallic grid is to reduce RCS deduced by impinging radar ray on the aperture. A radar ray incident on a grid net installed on a cavity may create six types of propagation. 1-Incident rays entering inside the cavity and backscattered from it.2-Incidebnt rays on the grid net and created reection rays as an array of scatterers. These rays may create a wave with phase difference of 180 degree with respect to the exiting rays from the cavity.3-Incident rays on the grid net create surface currents owing on the net and make travelling waves, which regenerate the magnetic and electric fields. These fields make again propagated waves against incident ones.4-Creeping waves.5-Diffracted rays due to leading edges of net's elements.6-Mutual impedance among elements of the net could be effective on the resultant RCS. Therefore, the author compares the effects of three out of six properties to a cavity without grid net. This comparison shows that RCS prediction of cavity having a grid net is much more reduced than that of without one.

Sabihi, Ahmad

2014-12-01

3

The radar cross section reduction of microstrip patches  

Microsoft Academic Search

The radar cross section (RCS) reduction of microstrip patch antennas for low-observable platforms is considered, with emphasis on the application of lossy superstrates. The observed effect of these on antenna parameters is related to expected RCS reduction using results from the literature. The RCS computed by a finite element method\\/method of moments code is also presented. Other RCS reduction techniques

C. B. Wilsen; D. B. Davidson

1996-01-01

4

Precision radar cross-section measurements for computer code validation  

Microsoft Academic Search

Precision measurements of the radar cross section (RCS) of simple rod and cylinder targets for all angles of incidence in a plane containing the long axis of the target are presented. The RCS is presented as a contour map as a function of the frequency and the incidence angle. These extensive measured RCS data are used as a reference for

S. R. Mishra; C. L. Larose; C. W. Trueman

1993-01-01

5

Radar cross section of insects  

NASA Astrophysics Data System (ADS)

X-band measurements of radar cross section as a function of the angle between insect body axis and the plane of polarization are presented. A finding of particular interest is that in larger insects, maximum cross section occurs when the E-vector is perpendicular to the body axis. A new range of measurements on small insects (aphids, and planthoppers) is also described, and a comprehensive summary of insect cross-section data at X-band is given.

Riley, J. R.

1985-02-01

6

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

SciTech Connect

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.

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

1992-07-01

7

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

SciTech Connect

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.

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

1992-07-01

8

Analysis and Simulation of Quantum Radar Cross Section  

NASA Astrophysics Data System (ADS)

We derive a modified analytical expression of a quantum radar cross section (QRCS). Subsequently, we present a comparison between the QRCS and a classical radar cross section (RCS) and analyze the factors that can affect the intensity of the peak and side lobes. Simulation results on a flat rectangular plate demonstrate that QRCS has a similar structure to that of RCS. The analysis of side-lobe structure can benefit the design of quantum stealth platforms as well as the research on quantum radars.

Liu, Kang; Xiao, Huai-Tie; Fan, Hong-Qi

2014-03-01

9

Radar Cross Section measurements of small Unmanned Air Vehicle Systems in non-cooperative field environments  

Microsoft Academic Search

The growing use of unmanned air vehicle systems (UAVS) is drawing increased interest in their radar signature to search and track radars. Because it is not always possible to transport UAVS to radar cross section (RCS) measurement facilities, a portable RCS measurement system has been developed and demonstrated in non-cooperative field environments. This paper presents the portable RCS measurement system

A. Bati; D. Hilliard

2009-01-01

10

Radar Cross Section of Moving Objects  

E-print Network

I investigate the effects of movement on radar cross section calculations. The results show that relativistic effects (the constant velocity case) can change the RCS of moving targets by changing the incident plane wave field vectors. As in the Doppler effect, the changes in the fields are proportional to $\\frac{v}{c}$. For accelerated objects, using the Newtonian equations of motion yields an effective electric field (or effective current density) on the object due to the finite mass of the conducting electrons. The results indicate that the magnetic moment of an accelerated object is different from that of an un-accelerated object, and this difference can change the RCS of the object. Results for moving sphere and non-uniformly rotating sphere are given and compared with static (\\textbf{v}=0) case.

Gholizade, H

2013-01-01

11

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

E-print Network

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

Haddadi, Hamed

12

Radar-cross-section reduction of wind turbines. part 1.  

SciTech Connect

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.

Brock, Billy C.; Loui, Hung; McDonald, Jacob J.; Paquette, Joshua A.; Calkins, David A.; Miller, William K.; Allen, Steven E.; Clem, Paul Gilbert; Patitz, Ward E.

2012-03-05

13

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

Microsoft Academic Search

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

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

1989-01-01

14

3-d simulations for radar cross-section reduction using plasma absorbers  

Microsoft Academic Search

Summary form only given. Radar cross section (RCS) is the measure of a target's ability to reflect radar signals in the direction of the radar receiver. A collisional unmagnetized plasma, surrounding the target, acts as a good absorber of electromagnetic waves over a wide frequency range, reducing its RCS. This has given rise to world wide interest in plasma stealth

B. Chaudhury; S. Chaturvedi

2006-01-01

15

Plume effect on radar cross section of missiles at HF band  

Microsoft Academic Search

The radar cross section of missiles at HF band is affected by the presence of the missile plume. In fact, although the plume is transparent at microwave frequencies, it reflects almost the totality of the energy at the HF band. In this paper, we evaluate the effect of the missile plume on its radar cross section (RCS) at HF band.

M. Martorella; R. Soleti; F. Berizzi; E. Dalle Mese

2003-01-01

16

Abstract--The wireless measurement of various physical quantities from the analysis of the RADAR Cross Sections  

E-print Network

modulation of passive electromagnetic (EM) sensors and then remotely measured from FMCW RADAR interrogation and chipless sensors; millimeter-wave FMCW radar; radar cross section I. INTRODUCTION he wireless measurement of a physical quantity from the analysis of the RADAR Cross Section (RCS) variability of passive sensors

Paris-Sud XI, Université de

17

Statistical moments of radar cross section  

NASA Astrophysics Data System (ADS)

The radar cross section for backscatter from a smooth closed convex surface reflector, as calculated from geometrical optics, is shown to have a mean value equal to A/4, where A is the total surface area of the reflector, and the mean is obtained by averaging over all aspects. Results are also given for the calculation of higher order moments and probability density functions.

Gordon, William B.

1993-04-01

18

RCS Aspects of MultiBand Radar Systems Composed of \\  

Microsoft Academic Search

An essential characteristic of any radar target is the measure of its ability to reflect energy to the receiving antenna. The parameter used to describe this ability is the radar cross section (RCS) of the target. Stealth techniques and technologies, which affect the efficiency of early warning radar systems currently in operation, are described in ref [1]. The problem is

I. Balajti

2006-01-01

19

Radar cross section of triangular trihedral reflector with extended bottom plate.  

SciTech Connect

Trihedral corner reflectors are the preferred canonical target for SAR performance evaluation for many radar development programs. The conventional trihedrals have problems with substantially reduced Radar Cross Section (RCS) at low grazing angles, unless they are tilted forward, but in which case other problems arise. Consequently there is a need for better low grazing angle performance for trihedrals. This is facilitated by extending the bottom plate. A relevant analysis of RCS for an infinite ground plate is presented. Practical aspects are also discussed.

Brock, Billy C.; Doerry, Armin Walter

2009-05-01

20

Relationship of radar cross section to the geometric size of orbital debris  

NASA Technical Reports Server (NTRS)

An accurate determination of the sizes of orbiting debris objects is essential to predicting collision rates, atmospheric decay rates, and fragmentation laws for orbiting objects. The radar cross section (RCS) is the most common means of estimating the size of orbiting objects. However, the RCS is prone to error due to Mie scattering, compositional effects, geometrical effects, tumbling, and other dependencies. Optical measurement methods are theoretically much more accurate, but necessitate estimates of the object's albedo. This paper examines the relationship of RCS and optical cross section to physical size and albedo, and presents rules useful for quantizing the physical size of space objects.

Badhwar, Gautam D.; Anz-Meador, Phillip D.

1990-01-01

21

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

NASA Technical Reports Server (NTRS)

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 from the more accurate modal results. On the other hand, the SBR approach allows for greater flexibility in geometrical modeling, and can be applied to problems where waveguide modes cannot be easily found. SBR results for an offset rectangular cavity and a circular cavity with rounded endplate are presented.

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

1989-01-01

22

Lunar Radar Cross Section at Low Frequency  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

23

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

SciTech Connect

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.

Poland, D; Simpson, R

2000-07-01

24

Radar cross section measurements of frequency selective terahertz retroreflectors  

NASA Astrophysics Data System (ADS)

The radar cross section of spherical retroreflectors operating at terahertz frequencies is investigated. Several spherical retroreflectors with diameters ranging from 2 mm to 8 mm were fabricated and their radar cross section was measured at 100 GHz, 160 GHz, and 350 GHz. A frequency selective surface was applied to the retroreflectors to demonstrate proof of concept of narrow-band terahertz retroreflection.

Williams, Richard J.; Gatesman, Andrew J.; Goyette, Thomas M.; Giles, Robert H.

2014-05-01

25

Radar cross section of a perfectly conducting, flat, polygonal plate over a dielectric, lossy half space: a closed form, physical optics expression  

Microsoft Academic Search

The Physical Optics approximation is employed in the derivation of a closed form expression for the Radar Cross Section (RCS) of a flat, polygonal, perfectly conducting (PEC) plate, located over a dielectric, possibly lossy half space. The well-known \\

Hristos T. Anastassiu

2002-01-01

26

A review of high-frequency radar cross section analysis capabilities at McDonnell Douglas Aerospace  

Microsoft Academic Search

Two basic types of physical-optics (PO)-based radar cross section (RCS) analysis codes have come to maturity in today's HF electromagnetic analysis environment. These are facet based and curved surface based codes. Facet codes have very fast analysis rates, while curved-surface codes are usually considered more accurate. At McDonnell Douglas Aerospace (MDA), the need for very reliable RCS results to guide

D. M. Elking; J. M. Roedder; D. D. Car; S. D. Alspach

1995-01-01

27

Research into Influence of Gaussian Beam on Terahertz Radar Cross Section of a Semicircular Boss  

NASA Astrophysics Data System (ADS)

In radar cross section (RCS) calculation of a rough surface, the model can be simplified into the scattering of geometrically idealized bosses on a surface. Thus the problem of the RCS calculation of a rough surface is changed to the RCS calculation of the semicircular boss. The RCS measurement of scale model can help save time and money. The utilization of terahertz in RCS is attractive because of its special properties: the wavelength of the terahertz wave can help limit the size of the model in a suitable range in the measurement of the scale model and get more detailed data in the measurement of the real object. However, usually the incident beam of a terahertz source is a Gaussian beam; in the theoretical RCS estimation, usually a plane wave is assumed as the incident beam for sake of simplicity which may lead to an error between the measurement and calculation results. In this paper, the method of images is used to calculate the RCS of a semicircular boss at 2.52 THz and the results are compared to the one calculated when the incident beam is a plane wave.

Li, Hui-Yu; Li, Qi; She, Jian-Yu; Zhao, Yong-Peng; Chen, De-Ying; Wang, Qi

2013-08-01

28

A study of radar cross section measurement techniques  

NASA Technical Reports Server (NTRS)

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.

Mcdonald, Malcolm W.

1986-01-01

29

Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces  

NASA Astrophysics Data System (ADS)

Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

Li, Yongfeng; Zhang, Jieqiu; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Xu, Zhuo; Zhang, Anxue

2014-06-01

30

Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces  

SciTech Connect

Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya [College of Science, Air Force Engineering University, Xi'an, Shaanxi 710051 (China); Zhang, Jieqiu [College of Science, Air Force Engineering University, Xi'an, Shaanxi 710051 (China); Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Zhang, Anxue [School of Electronics and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2014-06-02

31

Method based on physical optics for the computation of the radar cross section including diffraction and double effects of metallic and absorbing bodies modeled with parametric surfaces  

Microsoft Academic Search

A method to compute the monostatic radar cross section (RCS) of complex bodies modeled by nonuniform rational B-spline (NURBS) surfaces is presented. The bodies can be covered by any kind of radar absorbing material (RAM) with electric and\\/or magnetic losses. Physical optics (PO) is used to obtain the scattered field of each surface. Fresnel coefficients are included in the stationary

Francisco Saez de Adana; Iván González Diego; Oscar Gutiérrez Blanco; Pablo Lozano; Manuel F. Cátedra

2004-01-01

32

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

NASA Astrophysics Data System (ADS)

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.

Huang, Xianjun; Hu, Zhirun; Liu, Peiguo

2014-11-01

33

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

SciTech Connect

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.

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

34

Planar near-field scanning for compact range bistatic radar cross-section measurement. Thesis Final Report  

NASA Technical Reports Server (NTRS)

The design, construction, and testing of a low cost, planar scanning system to be used in a compact range environment for bistatic radar cross-section (bistatic RCS) measurement data are discussed. This scanning system is similar to structures used for measuring near-field antenna patterns. A synthetic aperture technique is used for plane wave reception. System testing entailed comparison of measured and theoretical bistatic RCS of a sphere and a right circular cylinder. Bistatic scattering analysis of the ogival target support, target and pedestal interactions, and compact range room was necessary to determine measurement validity.

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

1991-01-01

35

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

NASA Technical Reports Server (NTRS)

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.

1997-01-01

36

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

NASA Technical Reports Server (NTRS)

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.

1998-01-01

37

Design and fabrication of a microstrip patch antenna with a low radar cross section in the X-band  

NASA Astrophysics Data System (ADS)

In this study, the authors developed a radar absorbing method to reduce the antenna radar cross section (RCS) without any loss of antenna performance. The new method was based upon an electromagnetic bandgap (EBG) absorber using conducting polymer (CP). First, a microstrip patch antenna was made by using a copper film and glass/epoxy composite materials, which are typically used for load-bearing structures, such as aircraft and other vehicles. Then, CP EBG patterns were also designed that had a 90% electromagnetic (EM) wave absorbing performance within the X-band (8.2-12.4 GHz). Finally, the CP EBG patterns were printed on the top surface of the microstrip patch antenna. The measured radar absorbing performance of the fabricated patch antenna showed that the frontal RCS of the antenna declined by nearly 95% at 10 GHz frequency while the CP EBG patterns had almost no effect on the antenna's performance.

Jang, Hong-Kyu; Lee, Won-Jun; Kim, Chun-Gon

2011-01-01

38

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

39

Radar Cross-Section of Targets Loaded with Metamaterial B. H. Henin1  

E-print Network

Radar Cross-Section of Targets Loaded with Metamaterial B. H. Henin1 , M. H. Al Sharkawy2 , and A. Circular metamaterial cylinder/cylinders with metamaterial coating are then used to show the effect of metamaterial characteristics in altering the forward and backward scattering cross-section of arbitrary shaped

Elsherbeni, Atef Z.

40

Radar cross section studies/compact range research  

NASA Technical Reports Server (NTRS)

Achievements in advancing the state-of-the-art in the measurement, control, and analysis of electromagnetic scattering from general aerodynamic targets are summarized. The major topics associated with this study include: (1) electromagnetic scattering analysis; (2) indoor scattering measurement systems; (3) RCS control; (4) waveform processing techniques; (5) material scattering and design studies; (6) design and evaluation of standard targets; and (7) antenna studies. Progress in each of these areas is reported and related publications are listed.

Burnside, W. D.; Dominek, A. K.; Gupta, I. J.; Newman, E. H.; Pathak, P. H.; Peters, L., Jr.

1989-01-01

41

Measurement of Stream Cross-Sectional Area Using Ground Penetration Radar with Empirical Mode Decomposition  

NASA Astrophysics Data System (ADS)

The cross-sectional area of streams is always one of the most important parameter for hydraulic and hydrological analysis. The conventional method for measuring the cross-sectional area at the gaging site is to divide the cross section of stream into a number of subsections by imaginary verticals. The water depths at various subsections are carried out by sounding weight or rod. The subsection area can be determined by the width and depths of the subsection. Then sum of area of all subsections gives the total cross-sectional area. By using the conventional method, the cross-sectional area measurement of stream is costly, time-consuming, and dangerous. A new method which composed of ground penetration radar (GPR) and empirical mode decomposition (EMD) is proposal to measure stream cross-sectional area efficiently and accurately. One of the advantages for applying GRP for measuring cross-sectional area is without putting people and equipment in contact with the water. The river bed can also be easily scanned by GPR. Then EMD is used to analysis the signals of GPR. By using EMD, the water surface and stream bed can be quickly and easily be determined for computing water depth. The new method is already applied to measure the stream cross-sectional area in Taiwan. The results show that the proposal method can quickly and accurately measure cross-sectional area in streams with shallow water.

Chen, Y.; Yu, S.; Kao, S.

2011-12-01

42

Deterministic Approach for Spatial Diversity Analysis of Radar Systems Using Near-Field Radar Cross Section of a Metallic Plate  

Microsoft Academic Search

A deterministic analysis of spatial diversity is presented in connection with radar systems. A numerical technique based on physical optics is used for our analysis. Contrary to statistical models, the proposed technique takes into account accurate near-field radar cross section of the target, and radiation characteristics of transmitting and receiving antennas. The power scattered by the target and received by

Ramin Deban; Halim Boutayeb; Ke Wu; Jean Conan

2010-01-01

43

Dynamic RCS Estimation of Chaff Clouds  

E-print Network

Dynamic RCS Estimation of Chaff Clouds DONG WOOK SEO HYUN-JAE NAM OH-JOON KWON NOH HOON MYUNG (GEC) method, this information is used to calculate the radar cross section (RCS) of the chaff cloud. The GEC method can estimate the RCS of a chaff cloud with an arbitrary orientation distribution

Myung, Noh-Hoon

44

Comparing EM Models to RCS Measurements for Building-Penetration Radar  

SciTech Connect

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.

Fasenfest, B; Ueberschaer, R

2007-05-18

45

Bistatic RCS tools for the assessment of multi-static radar  

Microsoft Academic Search

In order to develop a potential multi-static radar solution it is necessary first to understand the bistatic RCS characteristics of the expected targets. The target bistatic RCS characteristics not only aid determination of the position and density of the radar receive elements but also will determine the sensor capability required at each position. Bistatic RCS data is notoriously difficult to

D. A. R. Beale; A. L. Hume

2002-01-01

46

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

E-print Network

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

Myung, Noh-Hoon

47

Reduced backscattering cross section (Sigma degree) data from the Skylab S-193 radar altimeter  

NASA Technical Reports Server (NTRS)

Backscattering cross section per unit scattering area data, reduced from measurements made by the Skylab S-193 radar altimeter over the ocean surface are presented. Descriptions of the altimeter are given where applicable to the measurement process. Analytical solutions are obtained for the flat surface impulse response for the case of a nonsymmetrical antenna pattern. Formulations are developed for converting altimeter AGC outputs into values for the backscattering cross section. Reduced data are presented for Missions SL-2, 3 and 4 for all modes of the altimeter where sufficient calibration existed. The problem of interpreting land scatter data is also discussed. Finally, a comprehensive error analysis of the measurement is presented and worst case random and bias errors are estimated.

Brown, G. S.

1975-01-01

48

Fabrication of Radar Absorbing Structure and Evaluation of Radar Cross Section: Case Study of Hybrid Shells  

Microsoft Academic Search

Fiber-reinforced composite materials have outstanding mechanical and electrical properties; their applications have been expanded to commercial products as well as military components. Using composite materials, researchers have studied the radar absorbing, or `stealth' technology. In this research, to develop the radar absorbing structure (RAS), hybrid composite materials are fabricated into three-dimensional `C' and `U' shape shells. A series of experiments

Woo-Kyun Jung; Sung-Hoon Ahn; Bierng-Chearl Ahn; Seoung-Bae Park; Myung-Shik Won

2007-01-01

49

Detection and interpretation of ocean roughness variations across the Gulf Stream inferred from radar cross section observations  

NASA Technical Reports Server (NTRS)

Radar cross section data shows that the Gulf Stream has a higher cross section per unit area (interpreted here as a greater roughness) than the water on the continental shelf. A steep gradient in cross section was often seen at the expected location of the western boundary. There were also longer-scale (10-20 km) gradual fluctuations within the stream of significant magnitude. These roughness variations are correlated with the surface shear stress that the local wind imposes on the sea. Using the available surface-truth information concerning the wind speed and direction, an assumed Gulf Stream velocity profile, and high-resolution ocean-surface temperature data obtained by the VHRR onboard a NOAA-NESS polar-orbiting satellite, the present study demonstrates that the computed surface stress variation bears a striking resemblance to the measured radar cross-section variations.

Weissman, D. E.; Thompson, T. W.

1977-01-01

50

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

E-print Network

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

Paris-Sud XI, Université de

51

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

NASA Astrophysics Data System (ADS)

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.

Chung, Shen Shou Max

2011-11-01

52

Research into Influence of Gaussian Beam on Terahertz Radar Cross Section of a Conducting Cylinder  

NASA Astrophysics Data System (ADS)

In RCS measurement, usually the incident beam is a Gaussian beam or a similar beam source; however, in the theoretical RCS estimation, usually a plane wave is assumed as the incident beam for sake of simplicity. In this paper, the RCS of an infinite perfect conducting cylinder is estimated. In the estimation, the influence of a 2.52 THz laser beam on RCS is studied and the RCS in dependence with scattering angle and some other factors is obtained after the change of RCS equation; meanwhile, comparisons of RCS when the incident beam is a plane wave and a Gaussian beam respectively, are also given. The estimation results show, when the cylinder radius is 10 mm, choosing a beam width of 40 mm can keep the relative error less than 0.48 dB.

Li, Hui-Yu; Li, Qi; Xue, Kai; Zhao, Yong-Peng; Chen, De-Ying; Wang, Qi

2013-04-01

53

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

E-print Network

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

Tentzeris, Manos

54

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

E-print Network

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

Myung, Noh-Hoon

55

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

E-print Network

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

Paris-Sud XI, Université de

56

RCS Analysis of Plate Geometries, parts 1 and 2  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

57

Nonsinusoidal radar signal design for stealth targets  

Microsoft Academic Search

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

Nasser J. Mohamed

1995-01-01

58

Differential RCS of RFID tag P.V. Nikitin, K.V.S. Rao and R.D. Martinez  

E-print Network

Differential RCS of RFID tag P.V. Nikitin, K.V.S. Rao and R.D. Martinez The differential radar cross-section (RCS) of an RFID tag is an important parameter which determines the power of the modulated backscattered tag signal. The vector differential RCS of an RFID tag as seen by the reader is analysed and

Hannaford, Blake

59

Experimental Results of Air Target Detection With a GPS Forward-Scattering Radar  

Microsoft Academic Search

Forward-scattering radars (FSRs) acquire great interest when low radar cross section (RCS) targets are willing to be detected. This type of radar provides a countermeasure to stealth technology because, here, the targets' RCS depends only on the size and the shape of their silhouette. Passive radars use transmitters of opportunity as signal source, and they are therefore attractive too, due

Ion Suberviola; Iker Mayordomo; Jaizki Mendizabal

2012-01-01

60

790 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION,VOL. 42, NO. 6, JUNE 1994 Spectral Iterative Algorithm for RCS Computation in  

E-print Network

Algorithm for RCS Computation in Electrically Large or Intermediate Perfectly Conducting Cavities Juan M strong atten- tion in the last years in relation to radar cross section (RCS) reduction and target signatures. For RCS analysis of complex targets, duct structures such as jet engine intakes can often

Lozano, Angel

61

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

62

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

NASA Technical Reports Server (NTRS)

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.

Meneghini, R.; Atlas, D.

1984-01-01

63

Radar cross-section measurements and simulation of a tethered satellite. The small expendable deployer system end-mass payload  

NASA Technical Reports Server (NTRS)

The first Small Expendable Deployer System (SEDS-1), a tethered satellite system, was developed by NASA and launched March 29, 1993 as a secondary payload on a United State Air Force (USAF) Delta-2 launch vehicle. The SEDS-1 successfully deployed an instrumented end-mass payload (EMP) on a 20-km nonconducting tether from the second stage of the Delta 2. This paper describes the effort of NASA Langley Research Center's Antenna and Microwave Research Branch to provide assistance to the SEDS Investigators Working Group (IWG) in determining EMP dynamics by analyzing the mission radar skin track data. The radar cross section measurements taken and simulations done for this study are described and comparisons of the measured data with the simulated data for the EMP at 6 GHz are presented.

Cravey, Robin L.; Fralick, Dion T.; Vedeler, Erik

1995-01-01

64

Compact ranges in antenna and RCS measurements  

Microsoft Academic Search

With the increased complexity and extended frequency range of operation model measurements and far field test ranges are no longer suitable to satisfy the demand of accurate testing. Moreover plane wave test conditions are required for Radar Cross Section (RCS) measurements which represent a key point in stealth technology. Compact ranges represent the best test facilities available presently since they

B. Audone

1989-01-01

65

Analysis of normalized radar cross section (sigma-O) signature of Amazon rain forest using SEASAT scatterometer data  

NASA Technical Reports Server (NTRS)

The normalized radar cross section (NRCS) signature of the Amazon rain forest was SEASAT scatterometer data. Statistics of the measured (NRCS) values were determined from multiple orbit passes for three local time periods. Plots of mean normalized radar cross section, dB against incidence angle as a function of beam and polarization show that less than 0.3 dB relative bias exists between all beams over a range of incidence angle from 30 deg to 53 deg. The backscattered measurements analyzed show the Amazon rain forest to be relatively homogeneous, azimuthally isotropic and insensitive to polarization. The return from the rain forest target appears relatively consistent and stable, except for the small diurnal variation (0.75 dB) that occurs at sunrise. Because of the relative stability of the rain forest target and the scatterometer instrument, the response of versus incidence angle was able to detect errors in the estimated yaw altitude angle. Also, small instrument gain biases in some of the processing channels were detected. This led to the development of an improved NRCS algorithm, which uses a more accurate method for estimating the system noise power.

Bracalente, E. M.; Sweet, J. L.

1984-01-01

66

RCS Reduction of Ridged Waveguide Slot Antenna Array Using EBG Radar Absorbing Material  

Microsoft Academic Search

This letter investigates the application of EBG radar absorbing material (RAM) to asymmetric ridged waveguide slot antenna array to reduce its backward RCS. The EBG RAM is based on the mushroom-like EBG structure loaded with lumped resistances. A ridged waveguide slot antenna array with 4 times 10 slot elements was designed and built, part of the metal ground plane of

You-Quan Li; Hui Zhang; Yun-Qi Fu; Nai-Chang Yuan

2008-01-01

67

An improved composite surface model for the radar backscattering cross section of the ocean surface 2. Model response to surface roughness variations and the radar imaging of underwater bottom topography  

Microsoft Academic Search

In the companion paper we have presented an improved composite surface model for the calculation of normalized radar backscattering cross sections (NRCS) of the ocean surface. The proposed model accounts for the impact of the full two-dimensional ocean wave spectrum on the radar backscatter and was shown to reproduce measured absolute NRCS values for a variety of radar configurations and

Roland Romeiser; Werner Alpers

1997-01-01

68

CFRP-based broad-band Radar Absorbing Materials  

Microsoft Academic Search

Strong interest in radar absorbing materials (RAMs) took place with years due to their extensive sectors of application. RAMs are coatings whose electric and magnetic properties allow the absorption of microwave energy over certain frequencies. In particular, RAMs are very effective means of Radar Cross Section (RCS) reduction in the context of stealth technology. RCS reduction requires absorbers with broad-band

C. Mitrano; A. Balzano; M. Bertacca; M. Flaccavento; R. Mancinelli

2008-01-01

69

The design of broadband radar absorbing surfaces  

Microsoft Academic Search

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

Go H. Suk

1990-01-01

70

Radar cross section studies  

NASA Technical Reports Server (NTRS)

The ultimate goal is to generate experimental techniques and computer codes of rather general capability that would enable the aerospace industry to evaluate the scattering properties of aerodynamic shapes. Another goal involves developing an understanding of scattering mechanisms so that modification of the vehicular structure could be introduced within constraints set by aerodynamics. The development of indoor scattering measurement systems with special attention given to the compact range is another goal. There has been considerable progress in advancing state-of-the-art scattering measurements and control and analysis of the electromagnetic scattering from general targets.

Burnside, W. D.; Dominek, A. K.; Gupta, I. J.; Newman, E. H.; Pathak, P. H.; Peters, L., Jr.

1987-01-01

71

RCS reduction of a microstrip patch using lumped loads  

NASA Technical Reports Server (NTRS)

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.

Volakis, John L.; Alexanian, Angelos

1992-01-01

72

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

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

73

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)

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.

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

2012-01-01

74

GRECO: graphical electromagnetic computing for RCS prediction in real time  

Microsoft Academic Search

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

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

1993-01-01

75

Automated Target Recognition Using Passive Radar and Coordinated Flight Models  

E-print Network

approach to ATR compares the Radar Cross Section (RCS) of targets detected by a passive radar systemAutomated Target Recognition Using Passive Radar and Coordinated Flight Models Lisa M. Ehrman and Aaron D. Lanterman Center for Signal and Image Processing School of Electrical and Computer Engineering

Lanterman, Aaron

76

Meteor uxes and visual magnitudes from EISCAT radar event rates: a comparison with cross-section based magnitude estimates  

E-print Network

Meteor ¯uxes and visual magnitudes from EISCAT radar event rates: a comparison with cross also in meteor studies. The time resolution of the radar can be reduced to a few milliseconds, sucient to resolve the passage of individual meteors through the narrow ISR beam. Methods for group and phase

Paris-Sud XI, Université de

77

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

Microsoft Academic Search

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

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

1989-01-01

78

Computation of bistatic RCS with NEC2 in a context of passive ISAR system  

Microsoft Academic Search

The modelling of electromagnetic scattering from two neighboring targets is investigated using an integral formulation solved by the well-know NEC2 code. To save the computational resource, we extract the impedance matrix which is a good describer of targets. From the scattered field, the bistatic Radar Cross Section (RCS) is computed. The convergence of the method versus the size of the

F. Daout; F. Schmitt; G. Ginolhac

2005-01-01

79

Recruit an ANA for RCS tests  

NASA Astrophysics Data System (ADS)

For the conduction of valid radar cross-section (RCS) measurements, it is necessary to remove unwanted signals from the test data. However, the absolute accuracy of the measurements is limited because even the most carefully designed anechoic chamber allows some residual energy to reflect from the walls, floor, and ceiling. The present investigation is concerned with an automatic network analyzer (ANA) which makes it possible to eliminate the unwanted signals from the final results on the basis of a careful calibration. The ANA system consists of a network analyzer, a swept signal source, and a test set. Attention is given to hardware choices for RCS measurements, an extension of the dynamic range, an error model, error-correction procedures for RCS measurements, and the conduction of the measurements.

Boyles, J.

1985-03-01

80

Measurements at 13.9 GHz of the radar backscattering cross section of the North Sea covered with an artificial surface film  

NASA Technical Reports Server (NTRS)

The reduction of the Ku-band (13.9 GHz) normalized radar cross section (NRCS) by an artificial monomolecular surface film (oleyl alcohol) on the sea surface was measured in the North Sea during the 1975 Joint North Sea Wave Project, JONSWAP 75 experiment. The aim of the surface film experiment was to simulate natural surface films which often occur on the ocean surface and are produced by plankton or fish. NRCS measurements were obtained from an aircraft at incidence angles of 41 deg and 47 deg at vertical and horizontal polarizations. For winds between 3.5 and 4.4 m/sec the maximum measured reduction was 7.3 plus or minus 3.5 dB relative to the mean. In-situ measurements showed that the oleyl alcohol film reduced the surface tension from 74 to 43 dyne/cm.

Huehnerfuss, H.; Alpers, W.; Jones, W. L.

1978-01-01

81

The ogive as a RCS compact range standard  

NASA Technical Reports Server (NTRS)

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.

Dominek, A.; Nguyen, T.

1989-01-01

82

Using radar sea echo to estimate surface layer refractivity profiles  

Microsoft Academic Search

A method for inferring the atmospheric boundary layer evaporation duct height from sea clutter is described. The method is based on the observation that the radar signal from the evaporation duct manifests itself in the slope of the clutter power, while the horizontal variability of the sea clutter RCS (radar cross section) is a contaminant in the problem. The inversion

L. Ted ROgersl; Claude P. Hattan; Jeffery L. Krolik

1999-01-01

83

Adaptive Waveform Design for Improved Detection of Low-RCS Targets in Heavy Sea Clutter  

Microsoft Academic Search

The dynamic adaptation of waveforms for transmission by active radar has been facilitated by the availability of waveform-agile sensors. In this paper, we propose a method to employ waveform agility to improve the detection of low radar-cross section (RCS) targets on the ocean surface that present low signal-to-clutter ratios due to high sea states and low grazing angles. Employing the

Sandeep P. Sira; Douglas Cochran; Antonia Papandreou-Suppappola; Darryl Morrell; William Moran; Stephen D. Howard; Robert Calderbank

2007-01-01

84

ANGULAR-DIVERSITY RADAR RECOGNITION OF SHIPS BY TRANSFORMATION BASED APPROACHES --- INCLUDING NOISE EFFECTS  

Microsoft Academic Search

In this paper, the angular-diversity radar recognition of ships is given by transformation based approaches with noise effects taken into consideration. The ships and sea roughness are considered by simplified models in the simulation. The goal is to identify the similarity between the unknown target ship and known ships. Initially, the angular-diversity radar cross sections (RCS) from a ship are

Kun-Chou Lee; W. Huang; Chih-Wei Huang

2007-01-01

85

Feasibility study on scaled bistatic RCS measurements of aircraft in W-band to investigate misguidance by the Instrument-Landing-System  

Microsoft Academic Search

In this paper a measurement technique is presented, which allows the derivation of scaled bistatic radar cross sections of objects at ILS frequencies with a very simple measurement setup and an easy post processing procedure. Its functionality is proven with simple reference objects, which can be calculated by common simulation tools. First sets of bistatic RCS are presented for the

R. Geise; R. Piesiewicz; A. Enders; A. Schwithal

2008-01-01

86

High-frequency techniques for RCS prediction of plate geometries  

NASA Technical Reports Server (NTRS)

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.

Balanis, Constantine A.; Polka, Lesley A.

1991-01-01

87

Scattering Cross Section of Sound Waves by the Modal Element Method  

NASA Technical Reports Server (NTRS)

#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.

Baumeister, Kenneth J.; Kreider, Kevin L.

1994-01-01

88

On the ability of rough surface scattering approximations to predict hydrodynamic modulation of the ocean radar cross section - A numerical study  

NASA Technical Reports Server (NTRS)

Scattering from the ocean surface at microwave frequencies is often described by the Bragg scattering model or the two-scale model. Here, the ability of these models to predict cross section modulation is investigated by comparing Bragg and two-scale cross-sections with cross sections calculated by a numerical electromagnetic approach. The numerical method is used as the standard of comparison. For slightly rough surfaces, the Bragg model is found to be very accurate, but for much rougher surfaces, the two-scale model is superior and should be used for calculating both the absolute cross section and the change in cross section due to spatial or temporal modulation of the ocean wave height spectrum. These results are relevant to the interpretation of SAR images of ocean surface phenomena which perturb the wave height spectrum at ripple wavelengths.

Durden, Stephen L.; Vesecky, John F.

1989-01-01

89

Electromagnetic Wave Absorbing Technique Using Periodic Patterns for Low RCS Patch Array Antenna  

NASA Astrophysics Data System (ADS)

This paper presents an electromagnetic wave absorbing technique to reduce a radar cross-section (RCS) of a patch array antenna without compromising their antenna performance. The technique is based on periodic patterns, which is made of resistive materials. The 2×2 patch array antenna with a resonance frequency of 3.0 GHz was designed and fabricated. To reduce the RCS of the patch array antenna, the periodic patterns using a square patch element were proposed and applied to the surface between the four antenna patches. The printed lossy periodic patterns have radar absorbing performance at 12.0 GHz frequency. The measured results show that the lossy periodic patterns have no significant effect on the antenna radiation performance. On the other hand, the RCS is reduced by more than 98% compared to the conventional antenna at the target frequency.

Jang, Hong-Kyu; Lee, Yeon-Gwan; Shin, Jae-Hwan; Kim, Chun-Gon

2013-07-01

90

High-frequency techniques for RCS prediction of plate geometries  

NASA Technical Reports Server (NTRS)

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.

Balanis, Constantine A.; Polka, Lesley A.

1993-01-01

91

Radar target identification using various nearest neighbor techniques  

NASA Astrophysics Data System (ADS)

Radar target identification using decision-theoretic distance based methods have long been used for classifying unknown non-cooperative radar targets using their Radar Cross Section (RCS). This study revisits this subject using the recently developed Large Margin Nearest Neighbor (LMNN) technique in addition to other traditional nearest neighbor methods. Radar target recognition has been defined by two performance limiting issues namely 1) azimuth ambiguity (and/or erroneous estimation of target azimuth) and 2) presence of extraneous scatterers along the target. This study examines these different scenarios and highlights any of the benefits that LMNN may add to the radar target classification problem.

Jouny, I.

2014-06-01

92

Meteor fluxes and visual magnitudes from EISCAT radar event rates: a comparison with cross-section based magnitude estimates and optical data  

Microsoft Academic Search

Incoherent scatter radars (ISR) are versatile instruments for continuous monitoring of ionisation processes in the Earth’s atmosphere. EISCAT, The European Incoherent Scatter facility has proven effective also in meteor studies. The time resolution of the radar can be reduced to a few milliseconds, sufficient to resolve the passage of individual meteors through the narrow ISR beam. Methods for group and

A. Pellinen-Wannberg; A. Westman; G. Wannberg; K. Kaila

1998-01-01

93

Using a Kernel Adatron for Object Classification with RCS Data  

E-print Network

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.

Byl, Marten F; Rietman, Edward A

2010-01-01

94

RCS analysis and reduction for lossy dihedral corner reflectors  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

95

Balanced Cross Sections and Retrodeformation  

NSDL National Science Digital Library

In this exercise, students investigate the use of balanced cross sections and retrodeformation to study faults that do not break the surface and their application to tectonics, folding, and earthquake hazards. Introductory materials explain how to construct geologic cross-sections, the idea of balance in a cross-section, and the concept of retrodeformability, whether or not the structures seen in a cross section can be 'undeformed' into their original positions. Using the Kink Method, students will construct a cross-section and test a balanced cross section to see if it is retrodeformable. Instructions, a blank cross section with data, study questions, and a bibliography are provided.

Nicholas Pinter

96

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

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

97

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

NASA Technical Reports Server (NTRS)

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.

Reddy, C. J.

1998-01-01

98

Cross Section Flyer  

NSDL National Science Digital Library

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.

2010-01-01

99

Monostatic Reflectivity and Transmittance of Radar Absorbing Materials at 650 GHz  

NASA Astrophysics Data System (ADS)

Transmittance and monostatic reflectivity of different radar absorbing materials at 650 GHz are presented. The reflectivity was measured in plane-wave conditions in a radar cross-section (RCS) range with vertical polarization. The lowest reflectivity level (-70 dB) was achieved with commercial absorbers TK THz RAM and Firam-500 with oblique incidence angles. Floor carpets were also studied, and the reflectivity level of those was found to be sufficiently low (from -50 to -60 dB) for use in antenna test ranges. Results agree with earlier studies and indicate the applicability of the RCS method in reflectivity measurements also at 650 GHz.

Tamminen, Aleksi; Lonnqvist, Anne; Mallat, Juha; Raisanen, Antti V.

2008-03-01

100

Characteristics and optimization of radar target with plasma cover  

NASA Astrophysics Data System (ADS)

In this paper, we investigated the characteristic of radar target, the spherical and the pyramidal missile warheads, and compared the RCS and performance of the targets with and without the cover of the plasma metamaterials. Numerical simulation is obtained by the numerical calculation Finite-difference time-domain method (FDTD). The parameters of plasmonic structures as a metamaterial cloak was designed and optimized. The relationship between the parameters of the cloak and the corresponding electromagnetic characteristic of the target are analyzed by the simulation and discussion in broadband radar signals. After optimization, the plasma cover could attenuate 40 dBsm of the radar cross section (RCS) of the targets maximally. The result shows that the anomalous phenomenon of cloaking and stealth effects induced by plasma materials for the radar target, which might have potential application of military affairs.

Yang, Ying-ying; Zhao, Wei-fang; Wang, Wen-ting; Yi, Xiao-jing; Ji, Jun-wen; Lin, Xue-chun

2013-09-01

101

Signature management of radar returns from wind turbine generators  

NASA Astrophysics Data System (ADS)

The large radar cross section of wind turbine generator (WTG) blades combined with high tip speeds can produce significant Doppler returns when illuminated by a radar. Normally, an air traffic control radar system will filter out large returns from stationary targets, but the Doppler shifts introduced by the WTG blades are interpreted as moving aircraft that can confuse radar operators and compromise safety. A possible solution to this problem is to incorporate an active layer into the structure of the WTG blades that can be used to dynamically modulate the radar cross section (RCS) of the blade return. The active blade can operate in one of two modes: first the blade RCS can be modulated to provide a Doppler return that is outside the detectable range of the radar receiver system so that it is rejected; a second mode of operation is to introduce specific coding onto the Doppler returns so that they may be uniquely identified and rejected. The active layer used in the system consists of a frequency selective surface controlled by semiconductor diodes and is a development of techniques developed for active radar absorbers. Results of theoretical and experimental work using a 10 GHz Doppler radar and scale-model WTG are presented.

Tennant, A.; Chambers, B.

2006-04-01

102

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

NASA Technical Reports Server (NTRS)

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.

Lee, Teh-Hong; Burnside, Walter D.

1991-01-01

103

Cross Section of Sagittal Otolith  

USGS Multimedia Gallery

Cross section of a sagittal otolith from a juvenile Chinook salmon 79 days after emergence. The letters represent: H = hatch, E = emergence, FF = first feed, FW = freshwater residence, TDCK = tidal delta check, and D = tidal delta residence (40x objective)....

104

Improvement on RCS reduction using flat lossy focusing reflectors.  

PubMed

In this paper, we propose a planar non-periodic subwavelength resistive grating (SWRG). The phase front of the scattered fields can be completely manipulated through non-periodic design of the grating while high absorptivity is preserved. The SWRG has an interesting property similar to a resistive concave reflecting lens. Scattered wave is focused in the near-field region, and spread out in the far-field. This feature of non-periodic resistive grating can improve the original radar cross section (RCS) reduction up to 22.86 dB in the boresight direction comparing to the periodic counterpart. Non-periodic design of SWRG could have a substantial impact on stealth technology, aerospace engineering, and microwave anechoic chamber. PMID:24514847

Chin, Cheng-Yuan; Jou, Christina F

2013-12-30

105

Three radar imaging methods based on the one-dimensional laser range profile  

NASA Astrophysics Data System (ADS)

One-dimensional range profile is known as a simple radar imaging technology. Based on the imaging mechanism, the laser range profiles (LRPS) of the convex rotators in three different methods, which named as the Beam Scattering Method (BS method), Radar Cross Section Method (RCS method) and Surface Elements Method (SE method),were studied. In detail, BS method, which combined the laser beam pulse scattering theory and radar equation, is the very model that can be applied to the convex quadric rotary bodies, however, it may produce singular solutions in certain incident directions. The RCS method is just an extension of the theory of radar cross section theory and radar equation. According to the definition, the simplest forms of RCS which were then substituted into the radar equation were obtained, finally the one-dimensional range profiles were analytically resolved. The SE Method is a much more comprehensive theory to get the laser range profiles of arbitrary objects. The object should be first divided into numerous small triangle facets, and sum the backscattering power of these facets in the same distance, and in this way the final LRPS were deduced. In the meanwhile, the SE method is the most convenient way to evolve into the three-dimensional range profile. In the paper, the LRPS of a cone based on the three models above were simulated, it was found that the features and shape of each profiles were similar basically, but theoretical correction to SE method was still needed.

Mou, Yuan; Wu, Zhen-sen; Qu, Tan; Liao, Run-gui

2013-09-01

106

Radar signatures of indoor clutter for through-the-wall radar applications  

NASA Astrophysics Data System (ADS)

In through-the-wall radar (TTWR) applications, scattering by indoor clutter elements can greatly confound the detection of humans. This paper analyzes the spectral and azimuthal scattering characteristics of various types of individual furniture targets and compares these to humans. Radar cross section (RCS) values of furniture and humans are obtained using the finite difference time domain (FDTD) technique over the 1-5 GHz frequency range and the 0-360 azimuth angle range for both co- and cross-polarized scattering. In the case of furniture, RCS responses show to the highest returns when viewing the planar surfaces of the clutter objects. Objects consisting primarily of smaller planar surfaces with more complex geometrical features showed a more uniform response with no preferred orientation showing a larger response. Human RCS produced from the biological models showed a more constant RCS when viewing the co-polarized response, where the back produced the highest response due to the more planar surface. The cross-polarized response was more varied providing for a wider range of RCS values.

Bufler, Travis D.; Narayanan, Ram M.; Dogaru, Traian

2014-05-01

107

Design and applications of a versatile HF radar calibration target in low Earth orbit  

NASA Astrophysics Data System (ADS)

High frequency (HF) radars are used to detect ionospheric irregularities, meteor trails, and moving targets. The Precision Expandable Radar Calibration Sphere (PERCS) is a simple radar target in space to help determine the operational parameters of ground HF radars. PERCS will have a known radar cross section that is independent of observation direction within 0.5 dB. The PERCS satellite can be launched in a stowed configuration that has about 1 m in diameter. After launch, the PERCS will expand to a diameter of almost 10 m. Upon expansion, a stable wire frame is formed to act as a radar scatter target in the form of a polyhedral sphere. The simplest version of the sphere has 60 vertices (V60) that are joined to 90 rigid segments. Each segment is hinged so that the PERCS can be folded into a compact package for launch. Analysis of the V60 wire frame with a 10 m diameter shows that the radar cross section (RCS) is nearly independent of viewing angle up to 30 MHz. Another design with 240 vertices produces even better performance. Radar systems will be calibrated using the radar echo data and the precise knowledge of the target RCS, position, and velocity. The PERCS can reflect radar signals from natural targets such as field aligned and current driven irregularities not presently accessible from ground-based radars. The wire frame structure has several advantages over a metalized spheroid "balloon" with (1) much less drag, (2) larger radar cross section, and (3) lower fabrication cost.

Bernhardt, Paul A.; Siefring, Carl L.; Thomason, Joe F.; Rodriquez, Serafin P.; Nicholas, Andrew C.; Koss, Steven M.; Nurnberger, Mike; Hoberman, Chuck; Davis, Matthew; Hysell, David L.; Kelley, Michael C.

2008-02-01

108

Early Mesoderm Development Cross Section  

NSDL National Science Digital Library

In the context of a cross section between the amniotic cavity and yolk sac, this FlashTM animation depicts mesoderm formation and differentiation into somites, dermatomes, myotomes, sclerotomes, notochord and coelom. Simultaneous development of neural tube, gut and vitelline duct is also displayed.

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

2011-07-07

109

Revolutionizing Cross-sectional Imaging  

E-print Network

Cross-sectional imaging is so important that, six Nobel Prizes have been awarded to the field of nuclear magnetic resonance alone because it revolutionized clinical diagnosis. The BigBrain project supported by up to 1 billion euro each over a time period of 10 years predicts to "revolutionize our ability to understand internal brain organization" (Evan 2013). If we claim that cross-sectional imaging diagnosis is only semi-quantitative, some may believe because no doctor would ever tell their patient that we can observe the changes of this cross-sectional image next time. If we claim that BigBrain will make no difference in clinical medicine, then few would believe because no doctor would ever tell their patient to scan this part of the image and compare it with that from the BigBrain. If we claim that the BigBrain Project and the Human Brain Project have defects in their key method, one might believe it. But this is true. The key lies in the reconstruction of any cross-sectional image along any axis. Using Ga...

Fan, Yifang; Luo, Liangping; Lin, Wentao; Li, Zhiyu; Zhong, Xin; Shi, Changzheng; Newman, Tony; Zhou, Yi; Lv, Changsheng; Fan, Yuzhou

2014-01-01

110

Aircraft Wake RCS Measurement  

NASA Technical Reports Server (NTRS)

A series of multi-frequency radar measurements of aircraft wakes at altitudes of 5,000 to 25,00 ft. were performed at Kwajalein, R.M.I., in May and June of 1990. Two aircraft were tested, a Learjet 35 and a Lockheed C-5A. The cross-section of the wake of the Learjet was too small for detection at Kwajalein. The wake of the C-5A, although also very small, was detected and measured at VHF, UHF, L-, S-, and C-bands, at distances behind the aircraft ranging from about one hundred meters to tens of kilometers. The data suggest that the mechanism by which aircraft wakes have detectable radar signatures is, contrary to previous expectations, unrelated to engine exhaust but instead due to turbulent mixing by the wake vortices of pre-existing index of refraction gradients in the ambient atmosphere. These measurements were of necessity performed with extremely powerful and sensitive instrumentation radars, and the wake cross-section is too small for most practical applications.

Gilson, William H.

1994-01-01

111

LUMEN Cross-Section Tutorial  

NSDL National Science Digital Library

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 âÂÂImageâÂÂ), or an image from a CAT scan (by choosing âÂÂCTâÂÂ). 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.

Mcnulty, John A.

2010-07-20

112

Inverse Compton Cross Section Revisited  

NASA Astrophysics Data System (ADS)

The design of advanced machines working in the quantum regime (ELI-NP, IRIDE, e - ? and ? - ? colliders) requires to set the fundamentals needed to have an accurate prediction of the radiation qualities after the Compton scattering. Due to the high energy of the electron beam in the cases above mentioned, the quantum effects, referred as inverse Compton, which occur during the collision with the laser radiation, are not negligible. We present a rigorous method to obtain the inverse Compton cross section in the general case of not null initial momentum of the electrons from a pure QED calculation, avoiding the usual approaches based on the derivation of this cross section either from the Klein and Nishina formula and the Lorentz transformations or throught Feynman diagrams and Mandelstam invariants. In the derivation of the cross section from the transition amplitude we pay particular attention to the long time behavior of the system evolution. Proceeding in this way we obtain the transition probability in the time unit, which integrated over the solid angle of emission defines spectrum and number of the scattered photons.

Curatolo, C.; Lanz, L.; Petrillo, V.

113

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)

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.

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

1993-01-01

114

Radar scattering from foamed plastic target supports  

NASA Astrophysics Data System (ADS)

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.

Chambers, Michael W.

1991-12-01

115

Neutron cross sections: Volume 2, Neutron cross section curves  

SciTech Connect

Data is presented only for total (i.e., integrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy. The energy range has been limited to 0.01 eV to 200 MeV in order to exclude crystalline and magnetic effects for slow neutrons and relativistic effects for high energy neutrons. Angular distributions and partial reaction cross sections to specific excited states are not included. However, isometric state production cross sections have been included for isometric states with a half-life > 1 sec. Data which have been measured for a broad incident-neutron spectrum, e.g., Maxwellian are not included. A list of the reaction types included in this volume is given at the end of this section. Sums and ratios of specific reactions are not included (e.g., {sigma}{sub n,np+n,d} or {sup 235}U {sigma}{sub n,f}/{sup 239}Pu {sigma}{sub n,f}). A table of references to data for energies greater than 200 MeV is given in Appendix A. In this volume, the data have been grouped into sections corresponding to the element of the target nucleus in the neutron-induced reaction. These sections are ordered in increasing atomic number (Z). Within a section, graphical data are presented for the natural element followed by the isotopes of that element in order of increasing atomic mass (A). The bibliographic pages follow at the end of each section.

McLane, V.; Dunford, C.L.; Rose, P.F.

1988-01-01

116

Absorption cross section in Lifshitz black hole  

E-print Network

We derive the absorption cross section of a minimally coupled scalar in the Lifshitz black hole obtained from the new massive gravity. The absorption cross section reduces to the horizon area in the low energy and massless limit of s-wave mode propagation, indicating that the Lifshitz black hole also satisfies the universality of low energy absorption cross section for black holes.

Taeyoon Moon; Yun Soo Myung

2012-10-05

117

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

118

SNL RML recommended dosimetry cross section compendium  

SciTech Connect

A compendium of dosimetry cross sections is presented for use in the characterization of fission reactor spectrum and fluence. The contents of this cross section library are based upon the ENDF/B-VI and IRDF-90 cross section libraries and are recommended as a replacement for the DOSCROS84 multigroup library that is widely used by the dosimetry community. Documentation is provided on the rationale for the choice of the cross sections selected for inclusion in this library and on the uncertainty and variation in cross sections presented by state-of-the-art evaluations.

Griffin, P.J.; Kelly, J.G.; Luera, T.F. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); VanDenburg, J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)] [Science and Engineering Associates, Inc., Albuquerque, NM (United States)

1993-11-01

119

Detecting and mitigating wind turbine clutter for airspace radar systems.  

PubMed

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

Wang, Wen-Qin

2013-01-01

120

Cross Sections of Gamma-Proton Reactions  

Microsoft Academic Search

Using the University of Pennsylvania betatron, the energy dependences of the gamma-p cross sections of C, Al, Co, Ni, and Cb have been measured. The cross-section curves exhibit the resonance character found in gamma-n reactions. The significant parameters of each of the curves are tabulated. From the data of this paper and the known gamma-n cross-section data, the sum of

J. Halpern; A. K. Mann

1951-01-01

121

Annular-Cross-Section CFE Chamber  

NASA Technical Reports Server (NTRS)

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.

Sharnez, Rizwan; Sammons, David W.

1994-01-01

122

{sup 16}O neutron cross section evaluation  

SciTech Connect

This work has resulted from a need to compute more accurately the neutron scattering cross sections and angular distributions for {sup 16}O. Several oxygen evaluations have been performed in the past with R-Matrix theory, including ENDF/B-V and ENDF/B-VI. ENDF/B-VI is an improvement over ENDF/B-V, but still underpredicts in general the forward scattering of neutrons below 2.5 MeV. R-Matrix theory is used in describing cross sections at and near the resonance energies; but may not always be adequate in describing cross sections between resonances, especially when they are widely spaced. The optical (potential well) model of the nucleus is very good in representing cross sections that vary smoothly with energy, but not at describing all of the detailed resonance cross sections. A combination of the potential well model and R-Matrix theory was used for this work to represent cross sections with isolated resonances with large spacings between them. The total neutron cross section of oxygen-16 below 3.0 MeV has widely separated resonances and a dip in the cross section at 2.35 MeV. In the vicinity of resonances, where cross sections vary rapidly with energy, R-Matrix theory has been successful in fitting experimental data. In the region between resonances, an analytical procedure with physical basis is needed that agrees with data over a wide range of energies bracketing regions where experimental measurements are lacking.

Caro, E. [Lockheed Martin Corp., Schenectady, NY (United States)

1998-06-01

123

The Primitive Streak, Cross Section  

NSDL National Science Digital Library

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.

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

2011-06-23

124

Ku-Band rendezvous radar performance computer simulation model  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

125

A 240 GHZ POLARIMETRIC COMPACT RANGE FOR SCALE MODEL RCS MEASUREMENTS  

E-print Network

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

Massachusetts at Lowell, University of

126

Absolute partial photoionization cross sections of ozone.  

SciTech Connect

Despite the current concerns about ozone, absolute partial photoionization cross sections for this molecule in the vacuum ultraviolet (valence) region have been unavailable. By eclectic re-evaluation of old/new data and plausible assumptions, such cross sections have been assembled to fill this void.

Berkowitz, J.; Chemistry

2008-04-01

127

Photoionisation cross sections for Fe XVII  

NASA Astrophysics Data System (ADS)

This paper reports the first close-coupling photoionisation calculation of Fe XVII, and provides accurate total and partial cross sections for photon energies up to 450 Ryd. The total and first partial photoionisation cross sections, the latter obtained when the Fe XVIII ion is left in the 2s(22p^5;^2P^o) ground state, are dominated by resonance structure for photon energies in the range from threshold to excitation of the first excited state (2s2p(6;^2S) ) of Fe XVIII. This is the first time that such structure has been determined. The background cross section is found to be in good agreement (to within 10%) with the results of Verner and co-workers for the total cross section, and for the partial cross sections corresponding to 2p and 2s photoejection, respectively.

Leo, P. J.; Bell, K. L.; Keenan, F. P.

1998-05-01

128

High-frequency techniques for RCS prediction of plate geometries  

NASA Technical Reports Server (NTRS)

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.

Balanis, Constantine A.; Polka, Lesley A.

1992-01-01

129

High-frequency techniques for RCS prediction of plate geometries  

NASA Technical Reports Server (NTRS)

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.

Balanis, Constantine A.; Polka, Lesley A.

1991-01-01

130

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

NASA Technical Reports Server (NTRS)

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.

Goggans, Paul M.; Shumpert, Thomas H.

1991-01-01

131

Relative cross section and depolarization of NOCl  

NASA Technical Reports Server (NTRS)

A standard photon counting technique and an argon-ion laser with 4545, 4579, 4727, 4765, 4880, 4965, 5017 and 5145-A lasing lines, providing a measurable Raman spectrum from NOCl, were used in the measurement of the Raman scattering cross section of NOCl at a Raman shift of 334.4 plus or minus 1.6/cm in relation to the N2 Raman cross section. A polarization analyzer and a quartz wedge were placed in front of the entrance slit of the double monochromator for depolarization measurements. Diagrams are plotted to show the scattering cross section and depolarization measurement results.

Hoell, J. M.; Wade, W. R.

1974-01-01

132

Nucleon-Nucleon Total Cross Section  

NASA Technical Reports Server (NTRS)

The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

Norbury, John W.

2008-01-01

133

NNLO jet cross sections by subtraction  

E-print Network

We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

Gábor Somogyi; Paolo Bolzoni; Zoltán Trócsányi

2010-07-23

134

Cross section measurements with monoenergetic muon neutrinos  

E-print Network

The monoenergetic 236 MeV muon neutrino from charged kaon decay at rest (K[superscript +] ? ?[superscript +]?[subscript ?]) can be used to produce a novel set of cross section measurements. Applicable for short- and ...

Spitz, Joshua B.

135

A nuclear cross section data handbook  

SciTech Connect

Isotopic information, reaction data, data availability, heating numbers, and evaluation information are given for 129 neutron cross-section evaluations, which are the source of the default cross sections for the Monte Carlo code MCNP. Additionally, pie diagrams for each nuclide displaying the percent contribution of a given reaction to the total cross section are given at 14 MeV, 1 MeV, and thermal energy. Other information about the evaluations and their availability in continuous-energy, discrete-reaction, and multigroup forms is provided. The evaluations come from ENDF/B-V, ENDL85, and the Los Alamos Applied Nuclear Science Group T-2. Graphs of all neutron and photon production cross-section reactions for these nuclides have been categorized and plotted. 21 refs., 5 tabs.

Fisher, H.O.M.

1989-12-01

136

Bibliography of photoabsorption cross-section data  

NASA Technical Reports Server (NTRS)

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.

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

1970-01-01

137

International Evaluation of Neutron Cross Section Standards  

NASA Astrophysics Data System (ADS)

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.

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

138

Charmonium cross-sections and the QGP  

Microsoft Academic Search

In this contribution we summarize experimental information and theoretical results for the dissociation cross-sections of charmonium by light hadrons, which are of great importance for the identification of a quark-gluon plasma (QGP). Recent theoretical predictions for these cross-sections differ by orders of magnitude over the physically relevant energy range. The methods discussed here include a color-dipole model, meson exchange models,

T. Barnes

2003-01-01

139

Ultraviolet absorption cross sections of hydrogen peroxide  

NASA Technical Reports Server (NTRS)

Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

1978-01-01

140

Evaluation methods for neutron cross section standards  

SciTech Connect

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.

Bhat, M.R.

1980-01-01

141

Absorption cross section of RN black hole  

E-print Network

The behavior of a charged scalar field in the RN black hole space time is studied using WKB approximation. In the present work it is assumed that matter waves can get reflected from the event horizon. Using this effect, the Hawking temperature and the absorption cross section for RN black hole placed in a charged scalar field are calculated. The absorption cross section $\\sigma _{abs}$ is found to be inversely proportional to square of the Hawking temperature of the black hole.

Sini R.; V. C. Kuriakose

2007-08-23

142

Upper bound on neutrino cross sections  

NASA Technical Reports Server (NTRS)

Asymptotic bounds on the total cross sections of neutrino (weak) scattering processes are obtained. It is shown that the elastic neutrino-neutrino cross section obeys the following bound in the high energy region: sigma sub T (S) equals ImF(S,0)/S is less than or equal to const. (LogS) squared. Assumptions of analyticity, crossing, unitarity, polynomial boundaries, and a zero-condition on the absorptive part of the scattering amplitude, are used to obtain this bound.

Mickens, R. E.

1975-01-01

143

Cross-sectional area of flexible tubes  

Microsoft Academic Search

Kresch (1977) presented the results of calculations which determined the cross-sectional shapes assumed by flexible, elastic\\u000a tubes for varying transmural pressures. Extensions of these results are presented here in the form of graphs of the cross-sectional\\u000a area as a function of the transmural pressure. Since the circumferential arc length, theX-axis intercept and theY-axis intercept were necessarily computed, and are of

Edward Kresch

1979-01-01

144

RCS of a coated circular waveguide terminated by a perfect conductor  

NASA Technical Reports Server (NTRS)

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.

Lee, Choon S.; Lee, Shung-Wu

1987-01-01

145

Recent ARL borehole radar experiments  

NASA Astrophysics Data System (ADS)

The Microwave Sensors Branch of the Army Research Laboratory (ARL) recently evaluated the potential of a commercially available borehole radar system for an underground target detection application. We used this ground-penetrating system, which is capable of operation at either 100 or 250 MHz, to conduct experiments at a locally constructed test site. Since the site's soil characteristics would severely impact conclusions drawn from the collected data, we also obtained and analyzed soil samples in order to determine the electrical properties of the earth in the vicinity of the boreholes. In addition, we modeled and then built a canonical target, using this canonical target as an input to electromagnetic simulations. The outputs from these simulations guided us in the analysis and interpretation of the collected radar data. In this paper, we present a description of both the data collection itself and the results of a posteriori analysis of the collected data. We begin by describing the test site along with the procedures that we followed when conducting the experiments. Next, we present a soil analysis and the expected target radar cross section (RCS) obtained from the electromagnetic modeling simulations. We then discuss the implications of these results for system performance. Finally, we present an analysis of real data from the collection and compare it to what we expect based on the soil analysis and the output of the electromagnetic models. Collectively, these analyses provide an indication of the borehole radar's true potential for detecting underground targets.

Ranney, Kenneth; Stanton, Brian; Sullivan, Anders; Dogaru, Traian; Smith, Gregory; Ressler, Marc; Wong, David; Nguyen, Lam; Kappra, Karl; Tran, Chi; Kirose, Getachew; Costanza, John; Sichina, Jeff

2006-05-01

146

Neutron capture cross sections for nucleosynthesis  

SciTech Connect

Maxwellian Neutron capture cross sections important for nucleosynthesis processes in stars are computed from the recommended individual resonance parameters, as well as from the measured energy dependent cross sections. The experimental neutron capture cross sections, spanning the energy range from a few keV to about 500 keV are evaluated in the framework of the Lane-Lynn capture formalism by including several partial waves in the analysis. In addition, in a few cases, the neutron inelastic scattering channels are included. The feasibility of extrapolating the calculations to nuclides off the stability line is examined. The effect of stellar temperature in the range from 10 keV to 50 keV on the Maxwellian neutron capture cross sections is investigated. The Maxwellian capture cross sections at 30-KeV for {sup 93}Nb, {sup 127}I, {sup 141}Pr, {sup 150}Sm, {sup 152}Sm, {sup 154}Sm, and {sup 181}Ta are computed and are compared with other determinations.

Mughabghab, S.F.

1997-07-01

147

Medical radar considerations for detecting and monitoring Crohn's disease  

NASA Astrophysics Data System (ADS)

Crohn's disease is a condition that causes inflammation and associated complications along any section of the digestive tract. Over the years, numerous radiological and endoscopic methods as well as the use of ultrasound have been developed to examine and diagnose inflammatory bowel disorders such as Crohn's disease. While such techniques have much merit, an alternative medical solution that is safe, non-invasive, and inexpensive is proposed in this paper. Reflections from electromagnetic signals transmitted by an ultra-wide band (UWB) radar allow for not only range (or extent) information but also spectral analysis of a given target of interest. Moreover, the radar cross-section (RCS) of an object measures how detectable the electromagnetic return energy of such an object is to the radar. In the preliminary phase of research, we investigate how disparities in the dielectric properties of diseased versus non-diseased portions of the intestines can aid in the detection of Crohn's disease. RCS analysis from finite-difference time-domain (FDTD) method simulations using a simple 3D model of the intestines are presented. The ultimate goal of our research is to design a UWB radar system using a suitable waveform to detect and monitor Crohn's disease.

Smith, Sonny; Narayanan, Ram M.; Messaris, Evangelos

2014-05-01

148

Total quadruple photoionization cross section of beryllium  

SciTech Connect

In a quasiclassical framework, we formulate the quadruple ionization by single-photon absorption of the Coulomb five-body problem. We present the quadruple photoionization total cross section of the ground state of beryllium for energies up to 620 eV. Our results for energies close to threshold are in agreement with the Wannier threshold law for four-electron escape. In addition, the agreement of our results with a shape formula provides support for the overall shape of our total quadruple cross section. Finally, we find that the photon energy where the maximum of the total photoionization cross section occurs for single, double, triple, and quadruple photoionization of H, He, Li, and Be, respectively, seems to follow a linear relation with the threshold energy for complete breakup of the respective element.

Emmanouilidou, Agapi [ITS, University of Oregon, Eugene, Oregon 97403-5203 (United States)

2007-11-15

149

Top differential cross section measurements (Tevatron)  

SciTech Connect

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.

Jung, Andreas W.

2012-01-01

150

The hadronic cross section measurement at KLOE  

Microsoft Academic Search

KLOE uses the radiative return to measure cross section sigma(e+e--->pi+pi-gamma) at the electron-positron collider DAPhiNE. Divinding by a theoretical radiator function, we obtain the cross section sigma(e+e--->pi+pi-gamma) for the mass range 0.35

A. Aloisio; F. Ambrosino; A. Antonelli; M. Antonelli; C. Bacci; M. Barva; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; S. A. Bulychjov; R. Caloi; P. Campana; G. Capon; T. Capussela; G. Carboni; F. Ceradini; F. Cervelli; G. Chiefari; P. Ciambrone; S. Conetti; E. De Lucia; A. De Santis; P. De Simone; G. De Zorzi; S. Dell'Agnello; A. Denig; A. Di Domenico; C. Di Donato; S. Di Falco; B. Di Micco; A. Doria; M. Dreucci; O. Erriquez; A. Farilla; G. Felici; A. Ferrari; M. L. Ferrer; G. Finocchiaro; C. Forti; P. Franzini; C. Gatti; P. Gauzzi; S. Giovannella; E. Gorini; E. Graziani; M. Incagli; W. Kluge; V. Kulikov; F. Lacava; G. Lanfranchi; J. Lee-Franzini; D. Leone; F. Lu; M. Martemianov; M. Martini; W. Mei; L. Merola; R. Messi; S. Miscetti; M. Moulson; S. Müller; F. Murtas; M. Napolitano; F. Nguyen; M. Palutan; E. Pasqualucci; L. Passalacqua; A. Passeri; V. Patera; F. Perfetto; E. Petrolo; L. Pontecorvo; M. Primavera; P. Santangelo; E. Santovetti; G. Saracino; R. D. Schamberger; B. Sciascia; A. Sciubba; F. Scuri; I. Sfiligoi; A. Sibidanov; T. Spadaro; E. Spiriti; M. Tabidze; L. Tortora; P. Valente; B. Valeriani; G. Venanzoni; S. Veneziano; A. Ventura; R. Versaci; I. Villella; G. Xu

2005-01-01

151

Neutron Capture Cross Section of 239Pu  

NASA Astrophysics Data System (ADS)

The 239Pu(n,?) cross section has been measured over the energy range 10 eV - 10 keV using the Detector for Advanced Neutron Capture Experiments (DANCE) as part of a campaign to produce precision (n,?) measurements on 239Pu in the keV region. Fission coincidences were measured with a PPAC and used to characterize the prompt fission ?-ray spectrum in this region. The resulting spectra will be used to better characterize the fission component of another experiment with a thicker target to extend the (n,?) cross section measurement well into the keV region.

Mosby, S.; Arnold, C.; Bredeweg, T. A.; Couture, A.; Jandel, M.; O'Donnell, J. M.; Rusev, G.; Ullmann, J. L.; Chyzh, A.; Henderson, R.; Kwan, E.; Wu, C. Y.

2014-09-01

152

New Parameterization of Neutron Absorption Cross Sections  

NASA Technical Reports Server (NTRS)

Recent parameterization of absorption cross sections for any system of charged ion collisions, including proton-nucleus collisions, is extended for neutron-nucleus collisions valid from approx. 1 MeV to a few GeV, thus providing a comprehensive picture of absorption cross sections for any system of collision pairs (charged or uncharged). The parameters are associated with the physics of the problem. At lower energies, optical potential at the surface is important, and the Pauli operator plays an increasingly important role at intermediate energies. The agreement between the calculated and experimental data is better than earlier published results.

Tripathi, Ram K.; Wilson, John W.; Cucinotta, Francis A.

1997-01-01

153

The $?^* ?^*$ total cross section in NLA BFKL  

E-print Network

We study the $\\gamma^* \\gamma^*$ total cross section in the NLA BFKL approach. We have extracted the NLO corrections to the photon impact factor from two recent papers of Balitsky and Chirilli and Chirilli and Kovchegov and used them to build several representations of the total cross section, equivalent within the NLA. We have combined these different representations with two among the most common methods for the optimization of a perturbative series, namely PMS and BLM, and compared their behavior with the energy with the only available experimental data, those from the LEP2 collider.

Dmitry Yu. Ivanov; Beatrice Murdaca; Alessandro Papa

2014-11-16

154

Revised cross section for RHIC dipole magnets  

SciTech Connect

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.

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

1991-01-01

155

Improved cross section calculations for astrophysical applications  

NASA Technical Reports Server (NTRS)

Modifications are proposed for the semiempirical equations and parameters of Silberberg and Tsao (1973) for partial cross section calculations of proton-nucleus reactions in cosmic rays. These modifications include: adjustment of general parameters; modification of energy dependence; effects of nuclear alpha-particle structure, deuteron emission, and even-charged products; peripheral reactions; fission reactions; averaging cross sections near boundaries of different parameters; elimination of certain special cases; and treatment of the Pt to Pb group that cannot yet be generalized to Z(t) less than 76.

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

1985-01-01

156

Universal Parameterization of Absorption Cross Sections  

NASA Technical Reports Server (NTRS)

Our prior nuclear absorption cross sections model is extended for light systems (A less than or equal to 4) where either both projectile and target are light particles or one is a light particle and the other is a medium or heavy nucleus. The agreement with experiment is excellent for these cases as well. Present work in combination with our original model provides a comprehensive picture of absorption cross sections for light, medium, and heavy systems, a very valuable input for radiation protection studies.

Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

1999-01-01

157

Infrared absorption cross sections of alternative CFCs  

NASA Technical Reports Server (NTRS)

Absorption cross sections have obtained in the infrared atmospheric window, between 600 and 1500 cm(exp -1), for 10 alternative hydrohalocarbons: HCFC-22, HCFC-123, HCFC-124, HCFC-141b, HCFC-142b, HCFC-225ca, HCFC-225cb, HFC-125, HFC-134a, and HFC-152a. The measurements were made at three temperatures (287K, 270K and 253K) with a Fourier transform spectrometer operating at 0.03 cm(exp -1) apodized resolution. Integrated cross sections are also derived for use in radiative models to calculate the global warming potentials.

Clerbaux, Cathy; Colin, Reginald; Simon, Paul C.

1994-01-01

158

Cross Sections From Scalar Field Theory  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

159

NEUTRON CROSS SECTIONS FOR NUCLEOSYNTHESIS STUDIES  

Microsoft Academic Search

Previous compilations of (n,?) cross sections of relevance for neutron capture nucleosynthesis in the big bang and in the slow neutron capture process (s process) have been updated to encompass information available up to December 1998; data references include work in process then and published subsequently. The experimental results for nuclei between H and Bi were critically surveyed, renormalized to

Z. Y. BAO; H. Beer; F. Käppeler; F. Voss; K. Wisshak; T. Rauscher

2000-01-01

160

LSP-Nucleus Elastic Scattering Cross Sections  

E-print Network

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.

J. D. Vergados; T. S. Kosmas

1997-01-02

161

Windows in direct dissociative recombination cross sections  

NASA Technical Reports Server (NTRS)

Model potential curves are used to show that large windows are present in direct dissociative-recombination cross sections from excited molecular-ion vibrational levels. The windows are due to the overlap of vibrational wave functions of the repulsive neutral states with the nodes of the ion vibrational wave function.

Guberman, Steven L.

1986-01-01

162

Neutron scattering lengths and cross sections  

Microsoft Academic Search

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

Varley F. Sears

1992-01-01

163

Stratigraphic Cross Section of Northeast Texas  

NSDL National Science Digital Library

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.

Keith, Minor; Cretaceousfossils.com

164

Atomic (p,n)-threshold cross sections  

NASA Astrophysics Data System (ADS)

The (p,n)-threshold cross section is calculated for a light atom wherein the role of an active K-shell electron is included a priori. We find that the usual nuclear threshold law is covered asymptotically well above threshold on the atomic scale.

Feagin, J. M.

1981-12-01

165

NIST XCOM: Photon Cross Sections Database  

NSDL National Science Digital Library

This web program 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

2003-11-10

166

Testing (Validating?) Cross Sections with ICSBEP Benchmarks  

SciTech Connect

We discuss how to use critical benchmarks from the International Handbook of Evaluated Criticality Safety Benchmark Experiments to determine the applicability of specific cross sections to the end-user's problem of interest. Particular attention is paid to making sure the selected suite of benchmarks includes the user's range of applicability (ROA).

Kahler, Albert C. III [Los Alamos National Laboratory

2012-06-28

167

Marine-crossing sections require extensive surveying  

SciTech Connect

Design of the marine-crossing sections of the Vancouver Island, B.C., natural-gas pipeline incorporated measures to preserve or mitigate any damage to the sensitive waters through which it would pass. This article on the project discusses the marine crossing construction: the steps in its design and the options for its construction.

Yamauchi, H.M. (Westcoast Energy Inc., Vancouver (CA))

1990-08-13

168

A reevaluation of radiation damage cross sections  

NASA Astrophysics Data System (ADS)

In the past years, INC models simulating spallation reactions have been undergoing considerable development, and their results are more and more scrutinized by experimental work. Recently, IAEA has led an international collaboration to independently benchmark various INC models. The preliminary results of this collaboration indicate that while the Bertini model performs well in predicting neutron production, it greatly lacks the capability to predict light charged particle emission compared to CEM'03 and INCL. This drives us to completely reevaluate the NCSU radiation damage cross section database, which was developed 7 years ago using a combination of CEM2k and Bertini models for benchmarking experimental data. The reevaluation currently involves just the CEM'03 model in MCNPX due our limited code access. Our preliminary results are in reasonable agreement with the NCSU database for the helium and hydrogen production cross section, but there are obvious differences for the displacement cross section. Such similarities and differences are being investigated, and the validity of the CEM'03 model for predicting radiation damage to materials is being examined. The reevaluated radiation damage cross sections presented in this paper are used in calculating radiation damage to the target assembly currently running at SNS, and the results are compared with those of previous studies.

Lu, W.; Gallmeier, F. X.; Geoghegan, P. J.; Ferguson, P. D.; Wechsler, M. S.

2012-12-01

169

Dijet cross sections in photoproduction at HERA  

Microsoft Academic Search

Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on x?OBS, the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and

S. Bhadra; M. L. Cardy; C.-P. Fagerstroem; W. R. Frisken; K. M. Furutani; M. Khakzad; W. B. Schmidke; R. L. Talaga; H. Zhang; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; F. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckert; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; T. Haas; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. J. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; N. Cartiglia; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; Q. Zhu; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; A. Kotanski; M. Przybycien; L. A. T. Bauerdick; U. Behrens; H. Beier; J. K. Bienlein; C. Coldewey; O. Deppe; K. Desler; G. Drews; M. Flasinski; D. J. Gilkinson; C. Glasman; P. Göttlicher; J. Große-Knetter; B. Gutjahr; W. Hain; D. Hasell; H. Heßling; H. Hultschig; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; O. Manczak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; B. Surrow; T. Voß; D. Westphal; G. Wolf; C. Youngman; J. F. Zhou; H. J. Grabosch; A. Kharchilava; A. Leich; M. Mattingly; A. Meyer; S. Schlenstedt; N. Wulff; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. de Pasquale; L. Votano; A. Bamberger; S. Eisenhardt; A. Freidhof; S. Söldner-Rembold; J. Schroeder; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; J. I. Fleck; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; L. Hagge; E. Lohrmann; J. Mainusch; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; F. Zetsche; T. C. Bacon; I. Butterworth; E. Gallo; V. L. Harris; B. Y. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. del Peso; J. Puga; J. Terron; J. F. de Trocóniz; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; M. Botje; F. Chlebana; A. Dake; J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; L. Lindemann; J. D. McFall; C. Nath; V. A. Noyes; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. Dal Corso; M. de Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; G. Marini; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; T. Dubbs; C. Heusch; M. van Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada; Y. Yamazaki; M. Chiba; R. Hamatsu; T. Hirose; K. Homma; S. Kitamura; Y. Nakamitsu; K. Yamauchi; R. Cirio; M. Costa; M. I. Ferrero; L. Lamberti; S. Maselli; C. Peroni

1995-01-01

170

Cross sections for positron scattering from ethane  

NASA Astrophysics Data System (ADS)

We report experimental and theoretical cross sections for positron scattering from the fundamental organic-chemistry molecule ethane (C2H6). The experimental total cross sections (TCSs) were obtained using a linear transmission technique, for energies in the range 0.1-70 eV and with an energy resolution of ˜0.25 eV (full width at half maximum). Agreement, over the common energy range, with the earlier TCS measurements of Floeder [J. Phys. BJPAMA40022-370010.1088/0022-3700/18/16/019 18, 3347 (1985)] is excellent, while both the present results and those of Floeder are consistently higher in magnitude than the data of Sueoka and Mori [J. Phys. BJPAMA40022-370010.1088/0022-3700/19/23/021 19, 4035 (1986)]. The present calculations employed the Schwinger multichannel method and were performed in the static plus polarization approximation for energies up to 10 eV. Our calculated elastic integral cross sections (ICSs) indicate a Ramsauer-Townsend minimum at around 1.4 eV in the Ag scattering symmetry, and a virtual state. In addition we calculated from our scattering cross section a scattering length of -13.83a0. Agreement between our measured TCS and calculated elastic ICS is found to be only qualitative, although this is perhaps not so surprising given the TCS below 10 eV in principle includes contributions from rotational, vibrational, and electronic-state excitation and positronium formation whereas the calculation does not.

Chiari, L.; Zecca, A.; Trainotti, E.; Bettega, M. H. F.; Sanchez, S. d'A.; Varella, M. T. do N.; Lima, M. A. P.; Brunger, M. J.

2013-03-01

171

Photoionization Cross Section of the Propargyl Radical and Some General Ideas for Estimating Radical Cross Sections  

NASA Astrophysics Data System (ADS)

A combination of velocity map ion imaging, mass spectrometry, and a laser-based vacuum ultraviolet light source was used to perform a new measurement of the absolute photoionization cross section of the propargyl radical. The measurements are in good agreement with the recent determination of Savee et al. [ J. Chem. Phys. 2012, 136, 134307 ], and significantly larger than an earlier determination. The results are discussed and rationalized in terms of some general ideas about absolute photoionization cross sections. The potential utility of these ideas is illustrated by using recent cross section measurements for a number of molecular radicals, including methyl, allyl and 2-propenyl, phenyl, and vinyl.

Xu, Hong; Pratt, S. T.

2013-10-01

172

Tables of nuclear cross sections for galactic cosmic rays: Absorption cross sections  

NASA Technical Reports Server (NTRS)

A simple but comprehensive theory of nuclear reactions is presented. Extensive tables of nucleon, deuteron, and heavy-ion absorption cross sections over a broad range of energies are generated for use in cosmic ray shielding studies. Numerous comparisons of the calculated values with available experimental data show agreement to within 3 percent for energies above 80 MeV/nucleon and within approximately 10 percent for energies as low as 30 MeV/nucleon. These tables represent the culmination of the development of the absorption cross section formalism and supersede the preliminary absorption cross sections published previously in NASA TN D-8107, NASA TP-2138, and NASA TM-84636.

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

1985-01-01

173

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

SciTech Connect

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.

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

174

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

SciTech Connect

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.

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

175

Inclusive jet cross section at the Tevatron  

SciTech Connect

The authors report preliminary measurements of the central inclusive jet cross section at 1.8 TeV by the D0 and the CDF collaborations at the p{anti p} Fermilab collider. They are based on an integrated luminosity of 92 and 87 pb-1, respectively. The cross sections are measured as a function of jet transverse energy in the pseudorapidity interval 0.1 < 1,711 < 0.7 (CDF), and the two pseudorapidity ranges 1,711 < 0.5 and 0.1 < Inj < 0.7 (D0). D0 reports good agreement with the Next-to-Leading Order QCD predictions currently available. CDF observes an excess above 200 GeV, which can be accommodated with a modification in the gluon distribution function at high x.

NONE

1998-01-01

176

Proton stopping cross sections of liquid water  

NASA Technical Reports Server (NTRS)

The proton stopping cross section of liquid water for the energy range from 40 keV to 10 MeV is calculated by applying the modified local-plasma model and employing a simple model of liquid water. The calculated stopping cross section of liquid water is about 5.6 percent to 14 percent lower than the calculated vapor-state results for the range of 80 to 500 keV and is about 8.5 percent to 13.4 percent lower than measured vapor-state results. The present results agree well with the measurements for ice crystals. The mechanism of this physical-state effect is also presented.

Xu, Y. J.; Khandelwal, G. S.; Wilson, J. W.

1985-01-01

177

Photonuclear Reaction Cross Sections for Gallium Isotopes  

E-print Network

The photon induced reactions which are named as photonuclear reactions have a great importance in many field of nuclear, radiation physics and related fields. Since we have planned to perform photonuclear reaction on gallium target with bremmstrahlung photons from clinical linear accelerator in the future, the cross-sections of neutron (photo-neutron ({\\gamma},xn)) and proton (photo-proton ({\\gamma},xn)) productions after photon activation have been calculated by using TALYS 1.2 computer code in this study. The target nucleus has been considered gallium which has two stable isotopes, 69Ga and 71Ga. According to the results, we have seen that the calculations are in harmony in the limited literature values. Furthermore, the pre-equilibrium and compound process contributions to the total cross-section have been investigated.

Serkan Akkoyun; Tuncay Bayram

2014-09-08

178

Inclusive jet cross section at CDF  

SciTech Connect

This contribution reports on preliminary measurements of the inclusive jet production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using data collected with CDF corresponding to an integrated luminosity of 385 pb{sup -1}. Two analyzes are presented: one uses the longitudinally invariant k{sub T} algorithm to reconstruct the jets, the other uses the midpoint algorithm. Both are limited to jets with rapidity in the range 0.1 < |y{sup jet}| < 0.7. The measured cross sections are in good agreement with next-to-leading order perturbative QCD predictions after including the non-perturbative corrections necessary to account for underlying event and hadronization effects.

Lefevre, R.; Martinez, M.; /Barcelona, IFAE

2005-01-01

179

Neutron cross section measurements at WNR  

SciTech Connect

The Weapons Neutron Research Facility has been used to obtain moderate-resolution total neutron cross section data for H, C, /sup 208/Pb, /sup 232/Th, /sup 238/U, and /sup 242/Pu over the energy range 5 to 200 MeV. Neutrons were produced by bombarding a 2.5-cm diam by 15-cm long Ta target with an 800 MeV pulsed proton beam from LAMPF. A 10.2-cm diam by 15.2-cm thick NE110 proton recoil detector was used at a flight path of 32 meters, giving a time-of-flight resolution of 60 ps/m. The total cross section results are compared to ENDF/BV evaluations and to previous data where possible.

Lisowski, P.W.; Archampaugh, G.F.; Moore, M.S.; Morgan, G.L.; Shamu, R.E.

1980-01-01

180

Electron ionization cross sections for atomic subshells.  

PubMed

Ionization of atoms is the first step in many analytical procedures. The cross section for ionizing a particular atomic shell is essential for calculating the magnitude of analytical signals. Calculations using atomic wave functions for various shells of all elements relevant for X-ray microanalysis over a range of electron energies up to 400 keV were performed. The calculations for high energies above threshold can be considerably simplified by using the mathematical form of the Bethe ridge that dominates the scattering in this region. Corrections for exchange at low energies above threshold are incorporated in these calculations. A selection of results showing the effects of different approximations on ionization cross sections for K, L, and M shells is presented. PMID:12597786

Rez, Peter

2003-02-01

181

Universal Parameterization of Absorption Cross Sections  

NASA Technical Reports Server (NTRS)

This paper presents a simple universal parameterization of total reaction cross sections for any system of colliding nuclei that is valid for the entire energy range from a few AMeV to a few AGeV. The universal picture presented here treats proton-nucleus collision as a special case of nucleus-nucleus collision, where the projectile has charge and mass number of one. The parameters are associated with the physics of the collision system. In general terms, Coulomb interaction modifies cross sections at lower energies, and the effects of Pauli blocking are important at higher energies. The agreement between the calculated and experimental data is better than all earlier published results.

Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

1997-01-01

182

Hadronic Cross Section Measurements at Snd  

NASA Astrophysics Data System (ADS)

The preliminary results on multihadron processes obtained with the SND detector at the e+e? collider VEPP-2000 in the energy range from 1 to 2 GeV are presented. The results are interesting in connection with their contribution to the total hadronic cross section, the muon g-2 and a possibility to study excited vector mesons properties. The nucleon anti-nucleon production was also studied.

Achasov, M. N.; Aulchenko, V. M.; Barnyakov, A. Yu.; Beloborodov, K. I.; Berdyugin, A. V.; Berkaev, D. E.; Bogdanchikov, A. G.; Botov, A. A.; Dimova, T. V.; Druzhinin, V. P.; Golubev, V. B.; Kardapoltsev, L. V.; Kasaev, A. S.; Kharlamov, A. G.; Kirpotin, A. N.; Koop, I. A.; Korol, A. A.; Koshuba, S. V.; Kovrizhin, D. P.; Kravchenko, E. A.; Kupich, A. S.; Martin, K. A.; Obrazovsky, A. E.; Pakhtusova, E. V.; Rogovsky, Yu. A.; Senchenko, A. I.; Serednyakov, S. I.; Shatunov, Yu. M.; Shtol, D. A.; Shwartz, D. B.; Silagadze, Z. K.; Skrinsky, A. N.; Surin, I. K.; Tikhonov, Yu. A.; Usov, Yu. V.; Zemlyansky, I. M.

2014-12-01

183

Inclusive jet cross section measurement at CDF  

SciTech Connect

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.

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

1996-08-01

184

Analytic Fits for Partial Photoionization Cross Sections  

Microsoft Academic Search

. We present a compact, uniform and complete set ofanalytic fits to the partial Hartree-Dirac-Slater photoionizationcross sections for the ground state shells of all atoms and ions ofelements from H to Zn (Z 30). Comparison with experimentand theory demonstrates generally high accuracy of the fits upto energies of 100 keV.Key words: atomic data -- atomic processes1. IntroductionPhotoionization cross sections of

D. G. Yakovlev; D. A. Verner

185

Modeling the Meteoroid Input Function at Mid-Latitude Using Meteor Observations by the MU Radar  

NASA Technical Reports Server (NTRS)

The Meteoroid Input Function (MIF) model has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. This model includes the assessment of potential observational biases, namely through the use of empirical measurements to characterize the minimum detectable radar cross-section (RCS) for the particular High Power Large Aperture (HPLA) radar utilized. This RCS sensitivity threshold allows for the characterization of the radar system s ability to detect particles at a given mass and velocity. The MIF has been shown to accurately predict the meteor detection rate of several HPLA radar systems, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR), as well as the seasonal and diurnal variations of the meteor flux at various geographic locations. In this paper, the MIF model is used to predict several properties of the meteors observed by the Middle and Upper atmosphere (MU) radar, including the distributions of meteor areal density, speed, and radiant location. This study offers new insight into the accuracy of the MIF, as it addresses the ability of the model to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. Furthermore, the interferometry capability of the MU radar allows for the assessment of the model s ability to capture information about the fundamental input parameters of meteoroid source and speed. This paper demonstrates that the MIF is applicable to a wide range of HPLA radar instruments and increases the confidence of using the MIF as a global model, and it shows that the model accurately considers the speed and sporadic source distributions for the portion of the meteoroid population observable by MU.

Pifko, Steven; Janches, Diego; Close, Sigrid; Sparks, Jonathan; Nakamura, Takuji; Nesvorny, David

2012-01-01

186

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.

187

Nuclear cross sections from strong relativity  

SciTech Connect

Some time age, a geometrization of the nuclear field (in particular, inside hadrons) was proposed, which - on the basis of the classical methods of General Relativity - allowed a unified description of gravitational and strong forces. Such as non-phenomenological approach yielded already interesting results in connection, e.g., with the general behavior of hadrons constituents and the spectrum of mesons. In this note the author aims to show how it is possible to get from that theory also some information about nuclear cross-sections.

Italiano, A. (Univ. Messina (Italy) Inst. Nazionale di Fisica Nucleare, Messina (Italy))

1991-06-01

188

Infrared absorption cross sections for trifluoromethane  

NASA Astrophysics Data System (ADS)

High-resolution infrared absorption cross sections for trifluoromethane have been determined over the range 950-1500 cm-1 from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125HR) and a 26-cm-pathlength cell. Spectra of trifluoromethane/dry synthetic air mixtures were recorded at 0.015 cm-1 resolution (calculated as 0.9/MOPD) at a number of temperatures and pressures (23-762 Torr and 188-294 K) appropriate for atmospheric conditions. Intensities were calibrated using composite trifluoromethane spectra taken from the Pacific Northwest National Laboratory (PNNL) IR database.

Harrison, Jeremy J.

2013-11-01

189

Top Production Cross Sections at D0  

SciTech Connect

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.

Kvita, Jiri

2009-07-01

190

Cross section measurements with monoenergetic muon neutrinos  

NASA Astrophysics Data System (ADS)

The monoenergetic 236 MeV muon neutrino from charged kaon decay at rest (K+??+??) can be used to produce a novel set of cross section measurements. Applicable for short- and long-baseline accelerator-based neutrino oscillation experiments, among others, such measurements would provide a "standard candle" for the energy reconstruction and interaction kinematics relevant for charged current neutrino events near this energy. This neutrino can also be exercised as a unique known-energy, purely weak interacting probe of the nucleus. A number of experiments are set to come online in the next few years that will be able to collect and characterize thousands of these events.

Spitz, J.

2014-04-01

191

First measurement of the charged current cross section at HERA  

NASA Astrophysics Data System (ADS)

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.

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

1994-03-01

192

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...

193

Single-level resonance parameters fit nuclear cross-sections  

NASA Technical Reports Server (NTRS)

Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

1970-01-01

194

Measurement of actinide neutron cross sections  

SciTech Connect

The maintenance of strong scientific expertise is criticalto the U.S. nuclear attribution community. It is particularly importantto train students in actinide chemistry and physics. Neutroncross-section data are vital components to strategies for detectingexplosives and fissile materials, and these measurements requireexpertise in chemical separations, actinide target preparation, nuclearspectroscopy, and analytical chemistry. At the University of California,Berkeley and the Lawrence Berkeley National Laboratory we have trainedstudents in actinide chemistry for many years. LBNL is a leader innuclear data and has published the Table of Isotopes for over 60 years.Recently, LBNL led an international collaboration to measure thermalneutron capture radiative cross sections and prepared the EvaluatedGamma-ray Activation File (EGAF) in collaboration with the IAEA. Thisfile of 35,000 prompt and delayed gamma ray cross-sections for allelements from Z=1-92 is essential for the neutron interrogation ofnuclear materials. LBNL has also developed new, high flux neutrongenerators and recently opened a 1010 n/s D+D neutron generatorexperimental facility.

Firestone, Richard B.; Nitsche, Heino; Leung, Ka-Ngo; Perry, DaleL.; English, Gerald

2003-06-15

195

Mental Visualization of Objects from Cross-Sectional Images  

ERIC Educational Resources Information Center

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…

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

2012-01-01

196

Determination of absolute photoionization cross sections of the phenyl radical  

E-print Network

via 193- or 248-nm dissociation of chlorobenzene. At 10.0 eV, the photoionization cross sections of chlorobenzene with a goal of determining its absolute PI cross sections using the known PI cross section wavelengths to create the radical and taking advantage of the multiple channels for chlorobenzene

Neumark, Daniel M.

197

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

NASA Technical Reports Server (NTRS)

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.

Minott, P. O.

1974-01-01

198

Elastic cross sections in an RSIIp scenario  

NASA Astrophysics Data System (ADS)

The elastic differential cross section is calculated at low energies (below 100 MeV) for the elements 3He, 20Ne, 40Ar, 14N, 12C, and for the 208Pb using a finite electromagnetic potential, which is obtained by considering a Randall–Sundrum II scenario modified by the inclusion of p compact extra-dimensions. The length scale is adjusted in the potential to compare with known experimental data and to set bounds for the parameter of the model. The effective four-dimensional (4D) electromagnetic potential is produced by a point charge, as seen from the three-brane that contains it, in uniform motion in an RSIIp scenario.

Arceo, R.; Pedraza, Omar; González-Espinosa, E.; Escalera Santos, G. J.; Díaz-Hernández, O.

2015-01-01

199

Correlation cross sections along the international border  

SciTech Connect

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.

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

200

Neutron average cross sections of Np237  

NASA Astrophysics Data System (ADS)

This work reports Np237 neutron resonance parameters obtained from the simultaneous analysis of time-of-flight data measured at the GELINA, ORELA, KURRI, and LANSCE facilities. A statistical analysis of these resonances relying on average R-matrix and optical model calculations was used to establish consistent l-dependent average resonance parameters involved in the description of the unresolved resonance range of the Np237 neutron cross sections. For neutron orbital angular momentum l=0, we obtained an average radiation width =39.3±1.0 meV, a neutron strength function 104S0=1.02±0.14, a mean level spacing D0=0.60±0.03 eV, and a potential scattering length R'=9.8±0.1 fm.

Noguere, G.

2010-04-01

201

Signal analysis by means of time-frequency (Wigner-type) distributions -- Applications to sonar and radar echoes  

SciTech Connect

Time series data have been traditionally analyzed in either the time or the frequency domains. For signals with a time-varying frequency content, the combined time-frequency (TF) representations, based on the Cohen class of (generalized) Wigner distributions (WD`s) offer a powerful analysis tool. Using them, it is possible to: (1) trace the time-evolution of the resonance features usually present in a standard sonar cross section (SCS), or in a radar cross section (RCS) and (2) extract target information that may be difficult to even notice in an ordinary SCS or RCS. After a brief review of the fundamental properties of the WD, the authors discuss ways to reduce or suppress the cross term interference that appears in the WD of multicomponent systems. These points are illustrated with a variety of three-dimensional (3-D) plots of Wigner and pseudo-Wigner distributions (PWD), in which the strength of the distribution is depicted as the height of a Wigner surface with height scales measured by various color shades or pseudocolors. The authors also review studies they have made of the echoes returned by conducting or dielectric targets in the atmosphere, when they are illuminated by broadband radar pings. A TF domain analysis of these impulse radar returns demonstrates their superior informative content. These plots allow the identification of targets in an easier and clearer fashion than by the conventional RCS of narrowband systems. The authors show computed and measured plots of WD and PWD of various types of aircraft to illustrate the classification advantages of the approach at any aspect angle. They also show analogous results for metallic objects buried underground, in dielectric media, at various depths.

Gaunaurd, G. [Naval Surface Warfare Center, Silver Spring, MD (United States). Carderock Div.] [Naval Surface Warfare Center, Silver Spring, MD (United States). Carderock Div.; Strifors, H.C. [National Defense Research Establishment, Stockholm (Sweden)] [National Defense Research Establishment, Stockholm (Sweden)

1996-09-01

202

Space shuttle RCS engine  

NASA Technical Reports Server (NTRS)

The design of the space shuttle RCS engine has the primary objective of reusability with minimum servicing. Engine S/N FT-2A has successfully completed all ten environmental (salt water spray, sand and dust, vibration and humidity) and hot fire cycles with no change in engine performance (steady state or pulse mode).

1973-01-01

203

Resonance capture cross section of Pb207  

NASA Astrophysics Data System (ADS)

The radiative neutron capture cross section of Pb207 has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77±8% to the solar abundance of Pb207. This corresponds to an r-process component of 23±8%, which is important for deriving the U/Th ages of metal poor halo stars.

Domingo-Pardo, C.; Abbondanno, U.; Aerts, G.; Álvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvár, F.; Berthoumieux, E.; Bisterzo, S.; Calviño, F.; Cano-Ott, D.; Capote, R.; Carrapiço, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krti?ka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J. L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

2006-11-01

204

Deviations from Rutherford-scattering cross sections  

NASA Astrophysics Data System (ADS)

Recent experiments have demonstrated the utility of high-energy backscattering for thin-film analysis, often exploiting elastic-scattering resonances to increase sensitivity to low- Z elements. However, higher- Z elements may also exhibit deviations from Rutherford scattering, and it is desirable to examine the problem theoretically so that such deviations can be predicted and corrected for. We have used the optical-model computer code SCAT86 to calculate the projectile energy Enr at which the scattering cross section begins to deviate from its Rutherford value. The results agree well with data for both alpha particle and proton projectiles, but the interaction potentials are complicated, and the program does not provide an analytical predictive formula. We have therefore developed a simple classical model which treats the interaction as a sum of Coulomb and Yukawa-like potentials. For small deviations from Coulomb scattering, the problem can be solved analytically, providing a simple expression for Enr which agrees well with both experimental data and SCAT86. The classical approach is valid for all but small-angle forward scattering and can easily be extended to heavier projectiles such as Li.

Bozoian, Michael; Hubbard, Kevin M.; Nastasi, Michael

1990-10-01

205

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

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.

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

206

Nonlinear acoustic waves in channels with variable cross sections  

NASA Astrophysics Data System (ADS)

The point symmetry group is studied for the generalized Webster-type equation describing nonlinear acoustic waves in lossy channels with variable cross sections. It is shown that, for certain types of cross section profiles, the allowed symmetry group is extended and the invariant solutions corresponding to these profiles are obtained. Approximate analytic solutions to the generalized Webster equation are derived for channels with smoothly varying cross sections and arbitrary initial conditions.

Kovalev, V. F.; Rudenko, O. V.

2012-05-01

207

High E{sub T} jet cross sections at CDF  

SciTech Connect

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.

Flaugher, B.; CDF Collaboration

1996-08-01

208

Scaling properties of proton-nucleus total reaction cross sections  

E-print Network

We study the scaling properties of proton-nucleus total reaction cross sections for stable nuclei and propose an approximate expression in proportion to Z^{2/3}\\sigma_{pp}^{total} + N^{2/3} \\sigma_{pn}^{total}. Based on this expression, we can derive a relation that enables us to predict a total reaction cross section for any stable nucleus within 10% uncertainty at most, using the empirical value of the total reaction cross section of a given nucleus.

Badawy Abu-Ibrahim; Akihisa Kohama

2010-05-03

209

Projectile and Lab Frame Differential Cross Sections for Electromagnetic Dissociation  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

210

Measured microwave scattering cross sections of three meteorite specimens  

NASA Technical Reports Server (NTRS)

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.

Hughes, W. E.

1972-01-01

211

The absolute scattering cross section at 50 MHz of equatorial electrojet irregularities  

NASA Astrophysics Data System (ADS)

Carefully calibrated radar scattering measurements have been made using the large 50-MHz Jicamarca antenna. Typical results from the altitudes of maximum echo power for the vertically directed beam are cross sections of about 1-2 x 10 to the -10th/m for strong daytime electrojet conditions with type 1 irregularities present, with values a factor of 10 or so smaller during moderate conditions when only type 2 are observed. These cross sections, which are very large in comparison with those for incoherent scatter (cross sections of about 5 x 10 to the -18th/m for an electron density of 10 to the 11/cu m), are not nearly large enough, however, to cause pseudo-absorption events on riometer records, as was suggested by D'Angelo in 1976. If a model for the wave number dependence of the irregularities is assumed, it is possible to relate the radar data, which correspond to a single point in vector wave number-space, to in situ measurements of the magnitude of the total density fluctuations which correspond to a single point in physical space (an integral over the vector wave number-spectrum). The comparisons are reasonable, but depend significantly upon the assumed large scale cutoff for type 2 irregularities and the small scale cutoff for type 1.

Farley, D. T.; Ierkic, H. M.; Fejer, B. G.

1981-03-01

212

e+e- Hadron Production Cross Sections at Belle  

NASA Astrophysics Data System (ADS)

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.

Crnkovic, Jason D.

2014-12-01

213

Partial photoneutron cross sections for the isomeric state 180Tam.  

PubMed

Photoneutron cross sections for (181)Ta(y, n) (180)Ta(m) were determined from simultaneous measurements of total cross sections (sigma(tot) and ground-state cross sections (sigma(gs)) for (180)Ta in photodisintegration of with laser Compton-backscattered rays. Techniques of direct neutron counting and photoactivation were used for the measurement of sigma(tot) and sigma(gs), respectively. The partial cross sections for the isomeric state serves as a novel probe of the nuclear level density of (180)Ta. Implications for the p- and s-process nucleosynthesis of (180)Ta(m) are given. PMID:16803099

Goko, S; Utsunomiya, H; Goriely, S; Makinaga, A; Kaihori, T; Hohara, S; Akimune, H; Yamagata, T; Lui, Y-W; Toyokawa, H; Koning, A J; Hilaire, S

2006-05-19

214

Resonance Averaged Photoionization Cross Sections for Astrophysical Models  

E-print Network

We present ground state photoionization cross sections of atoms and ions averaged over resonance structures for photoionization modeling of astrophysical sources. The detailed cross sections calculated in the close-coupling approximation using the R-matrix method, with resonances delineated at thousands of energies, are taken from the Opacity Project database TOPbase and the Iron Project, including new data for the low ionization stages of iron Fe I--V. The resonance-averaged cross sections are obtained by convolving the detailed cross sections with a Gaussian distribution over the autoionizing resonances. This procedure is expected to minimize errors in the derived ionization rates that could result from small uncertainties in computed positions of resonances, while preserving the overall resonant contribution to the cross sections in the important near threshold regions. The detailed photoionization cross sections at low photon energies are complemented by new relativistic distorted-wave calculations for Z12 at high energies, including inner-shell ionization. The effective cross sections are then represented by a small number of points that can be readily interpolated linearly for practical applications; a Fortran subroutine and data are available. The present numerically averaged cross sections are compared with analytic fits that do not accurately represent the effective cross sections in regions dominated by resonances.

M. A. Bautista; P. Romano; A. K. Pradhan

1997-12-03

215

Neutron-capture Cross Sections from Indirect Measurements  

SciTech Connect

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.

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

2011-10-18

216

Documentation of Uncertainties in Experimental Cross Sections for EXFOR  

NASA Astrophysics Data System (ADS)

Documentation of uncertainties and covariances in experimental nuclear reaction cross sections has been assessed. Following consideration of the importance of covariances for nuclear data in various nuclear applications, and presentation of a simple numerical example to demonstrate this point, the minimum basic concepts (mean, covariance, standard derivation, partial uncertainties, micro- and macro-correlation coefficients) are introduced. A deterministic approach to propagating the covariances in primary measured parameters (e.g., counts) to the derived cross sections is discussed, using a neutron-induced activation cross section measurement as an example. Finally, various approaches to documentation (publication, compilation) of experimental cross sections to facilitate their use in future evaluations are mentioned.

Otuka, N.; Smith, D. L.

2014-06-01

217

Positive Scattering Cross Sections using Constrained Least Squares  

SciTech Connect

A method which creates a positive Legendre expansion from truncated Legendre cross section libraries is presented. The cross section moments of order two and greater are modified by a constrained least squares algorithm, subject to the constraints that the zeroth and first moments remain constant, and that the standard discrete ordinate scattering matrix is positive. A method using the maximum entropy representation of the cross section which reduces the error of these modified moments is also presented. These methods are implemented in PARTISN, and numerical results from a transport calculation using highly anisotropic scattering cross sections with the exponential discontinuous spatial scheme is presented.

Dahl, J.A.; Ganapol, B.D.; Morel, J.E.

1999-09-27

218

Hafnium neutron cross sections and resonance analysis  

NASA Astrophysics Data System (ADS)

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.

Trbovich, Michael J.

219

Advanced ground-based ESCAN radars  

Microsoft Academic Search

Electronically scanned radars (ESCAN radars) are key system elements of ground based military systems being developed for air and missile defense against future threats including tactical ballistic missiles, high agile and low RCS targets like drones, ARMs, UAVs. The radar design is governed on the one hand by challenging requirements on ESCAN radar performance and on the other hand by

U. Fuchs; W. Sieprath

2005-01-01

220

Cross Sections for Inner-Shell Ionization by Electron Impact  

SciTech Connect

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.

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

221

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

222

Accuracy of the O(+)-O collision cross-section deduced from ionosphere-thermosphere observations  

NASA Technical Reports Server (NTRS)

Aeronomic observations applied to the empirical derivation of the ion-neutral collision cross-section -- a basic parameter governing the mutual interaction between the neutral and plasma components in the Earth's upper atmosphere -- have given values considerably larger than those derived from theory. The empirical scheme uses the plasma velocities obtained with the Incoherent Scatter Radar and the neutral winds obtained with the Fabry-Perot Interferometer. It is shown here that such an analysis overestimates the collision cross-section due to the effects of errors in the observables. The effect may be sufficiently large to bring about agreement with theory, and calls for a re-analysis of the aeronomic data using methods which minimize the bias caused by measurement errors.

Reddy, C. A.; Hoegy, W. R.; Pesnell, W. D.; Mayr, H. G.; Hines, C. O.

1994-01-01

223

Analysis of the Radar Reflectivity of Aircraft Vortex Wakes  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

224

Radar investigation of asteroids  

NASA Technical Reports Server (NTRS)

The initial radar observations of the mainbelt asteroids 9 Metis, 27 Euterpe, and 60 Echo are examined. For each target, data are taken simultaneously in the same sense of circular polarization as transmitted as well as in the opposite (OC) sense. Estimates of the radar cross sections provide estimates of the circular polarization ratio, and the normalized OC radar cross section. The circular polarization ratio, is comparable to values measured for other large S type asteroids and for a few much smaller, Earth approaching objects, most of the echo is due to single reflection backscattering from smooth surface elements.

Ostro, S. J.

1984-01-01

225

Electromgnetic-gravitational cross-sections in external elctromagnetic fields  

E-print Network

The classical processes: the conversion of photons into gravitons in the static electromagnetic fields are considered by using Feynman perturbation techniques. The differential cross sections are presented for the conversion in the electric field of the flat condesor and the magnetic field of the selenoid. A numerical evaluation shows that the cross sections may have the observable value in the present technical scenario.

Hoang Ngoc Long; Dang Van Soa; Tuan A. Tran

1994-10-03

226

Emission Cross Sections for Neutral Xenon Impacted by Xe+  

E-print Network

Emission Cross Sections for Neutral Xenon Impacted by Xe+ and Xe2+ by Jason D. Sommerville A Thesis Emission cross sections for Neutral Xenon Impacted by Xe+ and Xe2+ by Jason D. Sommerville is hereby for eleven transitions from the 5p5 6p configuration to the 5p5 6s configuration of neutral xenon occur- ring

King, Lyon B.

227

Analysis of cross sections using various nuclear potential  

SciTech Connect

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.

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

228

Learning of Cross-Sectional Anatomy Using Clay Models  

ERIC Educational Resources Information Center

We incorporated clay modeling into gross anatomy and neuro-anatomy courses to help students understand cross-sectional anatomy. By making clay models, cutting them and comparing cut surfaces to CT and MR images, students learned how cross-sectional two-dimensional images were created from three-dimensional structure of human organs. Most students…

Oh, Chang-Seok; Kim, Ji-Young; Choe, Yeon Hyeon

2009-01-01

229

Cross section for $ ??\\rightarrow ?^+ ?^- ?^0 $ in chiral perturbation theory  

E-print Network

We give the amplitude for $\\gamma\\gamma \\rightarrow \\pi^+\\pi^-\\pi^0$ in leading order chiral perturbation theory. For the case of real photons we calculate the total and differential cross section. Furthermore, we give the dependence of the total cross section on the invariant mass of one of the photons.

J. W. Bos; Y. C. Lin; H. H. Shih

1994-07-04

230

Single Event Upset cross sections at various data rates  

Microsoft Academic Search

We present data which show that Single Event Upset (SEU) cross section varies linearly with frequency for most devices tested. We show that the SEU cross section can increase dramatically away from a linear relationship when the test setup is not optimized, or when testing near the maximum operating frequency. We also observe non-linear behavior in some complex circuit topologies.

R. A. Reed; M. A. Carts; P. W. Marshall; C. J. Marshall; S. Buchner; M. La Macchia; B. Mathes; D. McMorrow

1996-01-01

231

Summary of the Workshop on Neutron Cross Section Covariances  

Microsoft Academic Search

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

Donald L. Smith

2008-01-01

232

Surface interpolation from sparse cross-sections using region correspondence  

Microsoft Academic Search

The ability to estimate a surface from a set of cross sections allows calculation of the enclosed volume and the display of the surface in three-dimensions. This process has increasingly been used to derive useful information from medical data. However, extracting the cross sections (segmenting) can be very difficult, and automatic segmentation methods are not sufficiently robust to handle all

Graham M. Treece; Richard W. Prager; Andrew H. Gee; Laurence H. Berman

2000-01-01

233

Fission Cross Section Measurements of Actinides at LANSCE  

SciTech Connect

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 235U standard. Recent measurements include the 233, 238U, 239-242Pu, and 243Am neutron-induced fission cross sections. In this paper preliminary results for fission cross sections of 243Am and 233U will be presented.

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

2011-08-01

234

Temperature-dependent absorption cross sections for hydrogen peroxide vapor  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

235

Variable Differential Cross Section Due to Nuclear Motion  

NASA Astrophysics Data System (ADS)

The standard differential cross section formula assumes a motionless massive point nucleus. However, nuclear oscillation is a reality, changing the position of the impact parameter in relation to the incoming beam of particles or ions thereby affecting the cross section. If the static differential cross section is d?/d?= (Ze^22??/8??0T)^2, an oscillator can be added to the formula describing the movement of the cross section so that the resulting formula for differential cross section is (Ze^22??/2/8??0T)^2 (Ax?i + Ay?j +Az?k. By taking in ot account nuclear motion there will be some reconciliation between experimental and theoretical values.

Brekke, Stewart

2007-10-01

236

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)

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.

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

1994-01-01

237

Proton-Nucleus Total Reaction Cross Sections and Total Cross Sections Up to 1 GeV  

Microsoft Academic Search

In this paper are presented tables of all directly measured total reaction cross sections and total cross sections for protons interacting with all complex nuclei (2H and heavier) for proton energies up to 1 GeV. Some semiempirical fittings to the data are also included.

R. F. Carlson

1996-01-01

238

Cross Section Sensitivity and Propagated Errors in HZE Exposures  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

239

Cross-Sectional Drawing Techniques And The Artist  

NASA Astrophysics Data System (ADS)

Although Democritus, a Greek pholosopher of the fifth century B.C. described the use of cross-sections in analyzing a solid form, this method was not extensively developed in art until the Renaissance. The earliest treatise documenting the integration of the cross-section and linear perspective is Piero della Francesca's De prospective pingendi (c. 1480), in which a drawing of the human head is mathematically conceived and plotted by means of cross-section contours. Piero's method anticipates contemporary biostereometric techniques and current theories of visual perception. Outside of theoretical treatises the complete cross-section rarely occurs in art, though certain pictorial elements such as the religious halo can be interpreted as cross-sections. The chan-ging representation of the halo in art of the Medieval, Renaissance and Baroque periods parallels the development of the artist's concepts and techniques for representing form and space. During the Renaissance and Baroque periods the widespread use of contour hatching, a drawing technique based on the cross-section, indicates that the cross-section concept has played a greater role in pictorial representation than has generally been recognized.

Berry, William A.

1980-07-01

240

Electron impact rotationally elastic total cross section for formamide  

NASA Astrophysics Data System (ADS)

This paper reports computational results of the total cross sections for electron impact on formamide (HCONH2) 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.

Vinodkumar, Minaxi; Limbachiya, Chetan; Desai, Hardik; Vinodkumar, P. C.

2014-09-01

241

Top quark pair production cross section at Tevatron  

SciTech Connect

An overview of the recent measurements of the top antitop quark pair production cross section in proton antiproton collisions at {radical}s = 1.96 TeV in lepton + jets and dilepton final states is presented. These measurements are based on 1-2.8 fb{sup -1} of data collected with the D0 and CDF experiments at the Fermilab Tevatron collider. The cross section is measured with a precision close to 8 % and found to be compatible with the standard model prediction. Interpretations of the cross-section measurements for charge higgs search and for top quark mass measurement are also discussed.

Shary, V.; /DAPNIA, Saclay

2009-05-01

242

Actinide Neutron-Induced Fission Cross Section Measurements At LANSCE  

NASA Astrophysics Data System (ADS)

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 235U standard while incident neutron energies are determined using the time-of-flight method. Recent measurements include the 233,238U, 239-242Pu and 243Am neutron-induced fission cross sections. Obtained data are presented in comparison with existing evaluations and previous data.

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

2011-06-01

243

Actinide Neutron-Induced Fission Cross Section Measurements At LANSCE  

SciTech Connect

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.

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

244

Comparison of fission and capture cross sections of minor actinides  

E-print Network

The fission and capture cross sections of minor actinides given in JENDL-3.3 are compared with other evaluated data and experimental data. The comparison was made for 32 nuclides of Th-227, 228, 229, 230, 233, 234, Pa-231, 232, 233, U-232, 234, 236, 237, Np-236, 237, 238, Pu-236, 237, 238, 242, 244, Am-241, 242, 242m, 243, Cm-242, 243, 244, 245, 246, 247 and 248. Given in the present report are figures of these cross sections and tables of cross sections at 0.0253 eV and resonance integrals.

Nakagawa, T

2003-01-01

245

Actinide neutron-induced fission cross section measurements at LANSCE  

SciTech Connect

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. A parallel-plate ionization chamber 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 ex isting evaluations and previous data.

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

2010-01-01

246

Neutron inelastic cross-section measurements for Mg24  

NASA Astrophysics Data System (ADS)

The ? production cross sections from neutron inelastic scattering on 24Mg were measured for neutron energies up to 18 MeV at GELINA (the Geel Linear Accelerator), the neutron source operated by EC-JRC-IRMM, Belgium. The level cross section and the total inelastic cross section were determined. We used the GAINS (Gamma Array for Inelastic Neutron Scattering) spectrometer with seven large-volume high-purity germanium (HPGe) detectors placed at 110? and 150? with respect to the beam direction. The neutron flux was determined with a U235 fission chamber. The results are compared with calculations performed with the talys 1.6 code using the default settings.

Olacel, A.; Borcea, C.; Dessagne, P.; Kerveno, M.; Negret, A.; Plompen, A. J. M.

2014-09-01

247

Cross sections for electron scattering from ?-tetrahydrofurfuryl alcohol  

NASA Astrophysics Data System (ADS)

We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of Rydberg electronic-states in ?-tetrahydrofurfuryl alcohol. The energy range of these experiments was 20-50 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely for the total cross section, elastic ICS, inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. Where possible, our calculated cross sections are compared to the limited available data of each scattering process.

Duque, H. V.; Chiari, L.; Jones, D. B.; Thorn, P. A.; Pettifer, Z.; da Silva, G. B.; Limão-Vieira, P.; Duflot, D.; Hubin-Franskin, M.-J.; Delwiche, J.; Blanco, F.; García, G.; Lopes, M. C. A.; Ratnavelu, K.; White, R. D.; Brunger, M. J.

2014-07-01

248

Capabilities of radar as they might relate to entomological studies  

NASA Technical Reports Server (NTRS)

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.

Skolnik, M. I.

1979-01-01

249

Measurement of inclusive jet cross sections in photoproduction at HERA  

NASA Astrophysics Data System (ADS)

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.

Collaboration, H1; Abt, I.; Ahmed, T.; Andreev, V.; Andrieu, B.; Appuhn, R.-D.; Arpagaus, M.; Babaev, A.; Bärwolff, H.; Bán, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bergstein, H.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besançon, M.; Biddulph, P.; Binder, E.; Bischoff, A.; Bizot, J. C.; Blobel, V.; Borras, K.; Bosetti, P. C.; Boudry, V.; Bourdarios, C.; Brasse, F.; Braun, U.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Büngener, L.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A. B.; Colombo, M.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cvach, J.; Dagoret, S.; Dainton, J. B.; Danilov, M.; Dann, A. W. E.; Dau, W. D.; David, M.; Deffur, E.; Delcourt, B.; Del Buono, L.; Devel, M.; De Roeck, A.; Dingus, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Drescher, A.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Ebbinghaus, R.; Eberle, M.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellis, N. N.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Fensome, I. F.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Flauger, W.; Fleischer, M.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Fuhrmann, P.; Gabathuler, E.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gellrich, A.; Gennis, M.; Genzel, H.; Gerhards, R.; Godfrey, L.; Goerlach, U.; Goerlich, L.; Goldberg, M.; Goodall, A. M.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Greif, H.; Grindhammer, G.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Handschuh, D.; Hanlon, E. M.; Hapke, M.; Harjes, J.; Haydar, R.; Haynes, W. J.; Heatherington, J.; Hedberg, V.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herma, R.; Herynek, I.; Hildesheim, W.; Hill, P.; Hilton, C. D.; Hladký, J.; Hoeger, K. C.; Huet, Ph.; Hufnagel, H.; Huot, N.; Ibbotson, M.; Itterbeck, H.; Jabiol, M.-A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Jansen, T.; Jönsson, L.; Johannsen, K.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kasarian, S.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Kaufmann, H. H.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Ko, W.; Köhler, T.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kur?a, T.; Kurzhöfer, J.; Kuznik, B.; Lamarche, F.; Lander, R.; Landon, M. P. J.; Lange, W.; Langkau, R.; Lanius, P.; Laporte, J. F.; Lebedev, A.; Leuschner, A.; Leverenz, C.; Levonian, S.; Lewin, D.; Ley, Ch.; Lindner, A.; Lindström, G.; Linsel, F.; Lipinski, J.; Loch, P.; Lohmander, H.; Lopez, G. C.; Lüers, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; 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.; Mikocki, S.; Milone, V.; Monnier, E.; Moreau, F.; Moreels, J.; Morris, J. V.; Müller, K.; Murín, P.; Murray, S. A.; Nagovizin, V.; Naroska, B.; Naumann, Th.; Newton, D.; Neyret, D.; Nguyen, H. K.; Niebergall, F.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg, M.; Oberlack, H.; Obrock, U.; Olsson, J. E.; Orenstein, S.; Ould-Saada, F.; Pascaud, C.; Patel, G. D.; Peppel, E.; Peters, S.; Phillips, H. T.; Phillips, J. C.; Pichler, Ch.; Pilgram, W.; Pitzl, D.; Prell, S.; Prosi, R.; Rädel, G.; Raupach, F.; Rauschnabel, K.; Reimer, P.; Ribarics, P.; Riech, V.; Riedlberger, J.; Riess, S.; Rietz, M.; Robertson, S. M.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rudowicz, M.; Ruffer, M.; Rusakov, S.; Rybicki, K.; Sahlmann, N.; Sanchez, E.; Sankey, D. P. C.; Savitsky, M.; Schacht, P.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmitz, W.; Schröder, V.; Schulz, M.; Schwind, A.; Scobel, W.; Seehausen, U.; Sell, R.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Shtarkov, L. N.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorn, I. O.; Smirnov, P.; Smith, J. R.; Smolik, L.; Soloviev, Y.; Spitzer, H.; Staroba, P.; Steenbock, M.; Steffen, P.; Steinberg, R.; Stella, B.; Stephens, K.; Stier, J.; Stösslein, U.; Strachota, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Taylor, R. E.; Tchernyshov, V.; Thiebaux, C.; Thompson, G.; Tichomirov, I.; Truöl, P.; Turnau, J.; Tutas, J.; Urban, L.; Usik, A.; Valkar, S.; Valkarova, A.; Vallée, C.; Van Esch, P.

1993-09-01

250

Total cross sections for positron and electron scattering from pyrimidine  

NASA Astrophysics Data System (ADS)

In this paper we report original measurements of total cross sections for positron scattering from the important biomolecule pyrimidine. The energy range of these measurements was 0.3-45 eV, while the energy resolution was ~260 meV. In addition, we report theoretical results, calculated within the independent atom-screened additivity rule (IAM-SCAR) formalism, for the corresponding electron impact total cross sections. In that case the energy range is 1-10 000 eV. Total cross sections are very important input data for codes that seek to simulate charged-particle tracks in matter, as they define the mean-free path between collisions. As the present data and computations are to the best of our knowledge the first total cross sections to be reported for either positron or electron scattering from pyrimidine, they fill an important void in our available knowledge in the literature.

Zecca, A.; Chiari, L.; García, G.; Blanco, F.; Trainotti, E.; Brunger, M. J.

2010-11-01

251

Stellar neutron capture cross sections of the Ba isotopes.  

NASA Astrophysics Data System (ADS)

The neutron capture cross sections of 134Ba, 135Ba, 136Ba, and 137Ba were measured in the energy range from 5 to 225 keV. Neutrons were produced via the 7Li(p, n)7Be reaction by bombarding metallic Li targets with a pulsed proton beam. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 10 keV and 100 keV. These stellar cross sections were used in an s-process analysis. The new cross sections are also important for the interpretation of barium isotopic anomalies, which were recently discovered in SiC grains of carbonaceous chondrite meteorites.

Voss, F.; Wisshak, K.; Guber, K.; Käppeler, F.; Reffo, G.

1994-03-01

252

12. CLOSEUP VIEW OF CROSS SECTION OF SPILLWAY FIFTY FEET ...  

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

12. CLOSE-UP VIEW OF CROSS SECTION OF SPILLWAY FIFTY FEET FROM LAKESHORE, SHOWING REMAINS OF SPILLWAY TIMBERS, LOOKING WEST - Three Bears Lake & Dams, North of Marias Pass, East Glacier Park, Glacier County, MT

253

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

NASA Astrophysics Data System (ADS)

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 ? leptons: muon-hadron, electron-hadron, electron-muon, and muon-muon. The analysis is based on a data sample corresponding to an integrated luminosity of 36pb-1, at a proton-proton center-of-mass energy of s=7TeV. 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.

Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andari, N.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bona, M.; Bondarenko, V. G.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.

2011-12-01

254

Cross section dependence of event rates at neutrino telescopes  

E-print Network

We examine the dependence of event rates at neutrino telescopes on the neutrino-nucleon cross section for neutrinos with energy above 1 PeV, and contrast the results with those for cosmic ray experiments. Scaling of the ...

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

2006-10-20

255

Computation of the effective cross section of thallium atom collisions  

Microsoft Academic Search

Translated from Izmer. Tekh.; 16: No. 2, 60-61 (Feb 1973). The ; experimental data on the distribution of velocities in molecular beams is used ; for computing the effective cross section of collisions for thallium atoms. ; (JFP);

Yu. G. Abashev; G. F. Voronin; R. A. Valitov

1973-01-01

256

Hadronic cross sections, elastic slope and physical bounds  

SciTech Connect

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.

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

2013-03-25

257

Reaction cross sections of carbon isotopes incident on a proton  

E-print Network

We systematically study total reaction cross sections of carbon isotopes with N=6-16 on a proton target for wide range of incident energies, putting an emphasis on the difference from the case of a carbon target. The analysis includes the reaction cross sections of ^{19,20,22}C at 40 AMeV, the data of which have recently been measured at RIKEN. The Glauber theory is used to calculate the reaction cross sections. To describe the intrinsic structure of the carbon isotopes, we use a Slater determinant generated from a phenomenological mean-field potential, and construct the density distributions. To go beyond the simple mean-field model, we adopt two types of dynamical models: One is a core+n model for odd-neutron nuclei, and the other is a core+n+n model for 16C and 22C. We propose empirical formulas which are useful in predicting unknown cross sections.

B. Abu-Ibrahim; W. Horiuchi; A. Kohama; Y. Suzuki

2007-10-23

258

Black Hole Cross Section at the Large Hadron Collider  

E-print Network

Black hole production at the Large Hadron Collider (LHC) was first discussed in 1999. Since then, much work has been performed in predicting the black hole cross section. In light of the start up of the LHC, it is now timely to review the state of these calculations. We review the uncertainties in estimating the black hole cross section in higher dimensions. One would like to make this estimate as precise as possible since the predicted values, or lower limits, obtain for the fundamental Planck scale and number of extra dimensions from experiments will depend directly on the accuracy of the cross section. Based on the current knowledge of the cross section, we give a range of lower limits on the fundamental Planck scale that could be obtained at LHC energies.

Douglas M. Gingrich

2006-09-06

259

Scaling Cross Sections for Ion-atom Impact Ionization  

SciTech Connect

The values of ion-atom ionization cross sections are frequently needed for many applications that utilize the propagation of fast ions through matter. When experimental data and theoretical calculations are not available, approximate formulas are frequently used. This paper briefly summarizes the most important theoretical results and approaches to cross section calculations in order to place the discussion in historical perspective and offer a concise introduction to the topic. Based on experimental data and theoretical predictions, a new fit for ionization cross sections is proposed. The range of validity and accuracy of several frequently used approximations (classical trajectory, the Born approximation, and so forth) are discussed using, as examples, the ionization cross sections of hydrogen and helium atoms by various fully stripped ions.

Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

2003-06-06

260

Absolute two-photon excitation cross-sections in NO  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

261

Universal nature of the atomic photoabsorption cross section  

Microsoft Academic Search

The spatial inhomogeneity of atomic electron-density distributions is shown to affect the photoabsorption cross section, in the statistical approximation of Brandt and Lundqvist, in characteristic ways that are apparent in an updated comprehensive compilation of recent experimental data.

K. F. Stanton

1972-01-01

262

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

263

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

264

RCS program evaluation plan options  

SciTech Connect

The Residential Conservation Service (RCS) Program evaluation plan is designed to provide an ongoing evaluation during the RCS Program's active period as well as a measurement of the RCS Program's cumulative effect after the program's termination. The study options described include utility case studies, random survey sampling, directed survey sampling, and remote data collection. Survey techniques are described and appropriate questions are suggested. Several sample selection criteria are included as background for a DOE policy decision on this issue. Present and anticipated data sources are listed and discussed. Statistical data analysis plans include a preliminary determination of required sample sizes.

Stovall, T.K.; Bayne, C.K.

1980-10-01

265

Absorption cross sections of the ClO dimer  

NASA Technical Reports Server (NTRS)

The absorption cross sections of the ClO dimer, ClOOCl, are important to the photochemistry of ozone depletion in the Antarctic. In this work, new measurements were made of the dimer cross sections at 195 K. the results yield somewhat lower values in the long wavelength region, compared to those currently recommended in the NASA data evaluation (JPL 94-26). The corresponding solar photodissociation rates in the Antarctic are reduced by about 40%.

Huder, K. J.; DeMore, W. B.

1995-01-01

266

Total photoproduction cross section measurement at HERA energies  

Microsoft Academic Search

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

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

267

Anomalous J/? suppression and charmonium dissociation cross sections  

NASA Astrophysics Data System (ADS)

We study J/? suppression in Pb+Pb collisions at CERN-SPS energies in hadronic matter with energy- and temperature-dependent charmonium dissociation cross sections calculated in the quark-interchange model of Barnes and Swanson. The charmonium dissociation cross sections depend sensitively on energy and increase significantly as temperature increases. We find that the variation of J/? survival probability from peripheral to central collisions can be explained as induced by hadronic matter absorption in central collisions.

Xu, Xiao-Ming; Wong, Cheuk-Yin; Barnes, T.

2003-01-01

268

Hadronic Cross sections: from cyclotrons to colliders to cosmic rays  

E-print Network

We present evidence for the saturation of the Froissart bound at high energy for {\\em all hadronic} total cross sections at high energies, and use this to unify $pp$ (and $\\bar p p$) total cross sections over the energy range from cyclotrons to colliders to ultra-high energy cosmic rays, an energy span from $\\sqrt s = 4$ GeV to 80 TeV.

Martin M. Block

2010-09-02

269

Absolute Total np and pp Cross Section Determinations  

E-print Network

Absolute total cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses of NN scattering data. These cross sections are compared with most recent ENDF/B and JENDL data files, and the Nijmegen partial-wave analysis. Systematic deviations from the ENDF/B and JENDL evaluations are found to exist in the low-energy region.

Arndt, R A; Laptev, A B; Strakovsky, I I; Workman, R L

2008-01-01

270

Absolute Total np and pp Cross Section Determinations  

E-print Network

Absolute total cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses of NN scattering data. These cross sections are compared with most recent ENDF/B and JENDL data files, and the Nijmegen partial-wave analysis. Systematic deviations from the ENDF/B and JENDL evaluations are found to exist in the low-energy region.

R. A. Arndt; W. J. Briscoe; A. B. Laptev; I. I. Strakovsky; R. L. Workman

2009-01-05

271

Photon cross-sections at ECM = 2-TeV  

SciTech Connect

Photon production rates have been studied by the D0 and CDF experiments in Run II of the Fermilab Tevatron Collider. Measurements of the inclusive isolated photon cross section and the di-photon cross section are presented, based on integrated luminosities of 0.3 fb{sup -1} and 0.2 fb{sup -1}, respectively. The results are compared to perturbative QCD calculations in various approximations.

Wobisch, M.; /Fermilab

2006-06-01

272

Electron inelastic-scattering cross sections in liquid water  

Microsoft Academic Search

Electron inelastic-scattering cross-section data for use as input in electron track-structure calculations in liquid water are re-examined and improved. The dielectric-response function used in such cross-sections is estimated on the basis of optical data and other experimental and theoretical information. The mean excitation energy for stopping power is obtained to be 81.8 eV. which is close to the recent experimental

M. Dingfelder; D. Hantke; M. Inokuti; H. G. Paretzke

1998-01-01

273

Electron inelastic-scattering cross sections in liquid water  

Microsoft Academic Search

Electron inelastic-scattering cross-section data for use as input in electron track-structure calculations in liquid water are re-examined and improved. The dielectric-response function used in such cross-sections is estimated on the basis of optical data and other experimental and theoretical information. The mean excitation energy for stopping power is obtained to be 81.8 eV, which is close to the recent experimental

Michael Dingfelder; Detlev Hantke; Mitio Inokuti; Herwig G. Paretzke

1999-01-01

274

Probability distribution of velocity in natural channel cross sections  

Microsoft Academic Search

The probability distribution of velocities in idealized parabolic channels and in regular and highly irregular natural stream cross sections follows a power law: F(v)=(v\\/V)c, where F(v) is the cumulative frequency distribution of velocity v, Vis the maximum velocity in the cross section, and c is a shape parameter. Values of Vand c can be estimated from current meter measurements via

S. Lawrence Dingman

1989-01-01

275

Double differential cross sections of carbonyl sulfide molecule  

NASA Astrophysics Data System (ADS)

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.

Kumar, Rajeev; Sanju

2013-06-01

276

(Absolute measurements of cross section neutrons): Progress report  

Microsoft Academic Search

Over the past year, the cross section project at the University of Michigan has continued activities in two major areas. In the Neutron Experimental Bay, we have been employing a 150 kV Cockcroft-Walton accelerator as a 14 MeV neutron generator in the measurement of a number of activation cross sections. These have included the completion of a measurement of a

Knoll

1988-01-01

277

Inclusive jet differential cross sections in photoproduction at HERA  

Microsoft Academic Search

Inclusive jet differential cross sections for the reaction ep ? jet + X at Q2 below 4 GeV2 have been measured with the ZEUS detector at HERA using an integrated luminosity of 0.55 pb?1. These cross sections are given in the kinematic region 0.2 < y < 0.85, for jet pseudorapidities in the ep-laboratory range ?1 < ?jet < 2

S. Bhadra; W. R. Frisken; K. M. Furutani; B. Musgrave; J. Repond; J. Schlereth; R. Stanek; R. L. Talaga; J. Thron; F. Arzarello; R. Ayad; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; P. Bruni; G. Cara Romeo; G. Castellini; M. Chiarini; L. Cifarelli; F. Cindolo; F. Ciralli; A. Contin; S. D'Auria; F. Frasconi; I. Gialas; P. Giusti; G. Iacobucci; G. Laurenti; G. Levi; A. Margotti; T. Massam; R. Nania; C. Nemoz; F. Palmonari; A. Polini; G. Sartorelli; R. Timellini; Y. Zamora Garcia; A. Zichichi; A. Bargende; J. Crittenden; K. Desch; B. Diekmann; T. Doeker; M. Eckart; L. Feld; A. Frey; M. Geerts; G. Geitz; M. Grothe; H. Hartmann; D. Haun; K. Heinloth; E. Hilger; H.-P. Jakob; U. F. Katz; S. M. Mari; A. Mass; S. Mengel; J. Mollen; E. Paul; Ch. Rembser; R. Schattevoy; J.-L. Schneider; D. Schramm; J. Stamm; R. Wedemeyer; S. Campbell-Robson; A. Cassidy; N. Dyce; B. Foster; S. George; R. Gilmore; G. P. Heath; H. F. Heath; T. J. Llewellyn; C. J. S. Morgado; D. J. P. Norman; J. A. O'Mara; R. J. Tapper; S. S. Wilson; R. Yoshida; R. R. Rau; M. Arneodo; L. Iannotti; M. Schioppa; G. Susinno; A. Bernstein; A. Caldwell; J. A. Parsons; S. Ritz; F. Sciulli; P. B. Straub; L. Wai; S. Yang; P. Borzemski; J. Chwastowski; A. Eskreys; K. Piotrzkowski; M. Zachara; L. Zawiejski; L. Adamczyk; B. Bednarek; K. Eskreys; K. Jelen; D. Kisielewska; T. Kowalski; E. Rulikowska-Zarebska; L. Suszycki; J. Zajac; T. Kedzierski; A. Kotanski; M. Przybycien; L. A. T. Bauerdick; U. Behrens; J. K. Bienlein; S. Böttcher; C. Coldewey; G. Drews; M. Flasinski; D. J. Gilkinson; P. Göttlicher; B. Gutjahr; T. Haas; W. Hain; D. Hasell; H. Heßling; H. Hultschig; Y. Iga; P. Joos; M. Kasemann; R. Klanner; W. Koch; L. Köpke; U. Kötz; H. Kowalski; W. Kröger; J. Krüger; J. Labs; A. Ladage; B. Löhr; M. Löwe; D. Lüke; O. Manczak; J. S. T. Ng; S. Nickel; D. Notz; K. Ohrenberg; M. Roco; M. Rohde; J. Roldán; U. Schneekloth; W. Schulz; F. Selonke; E. Stiliaris; T. Voß; D. Westphal; G. Wolf; C. Youngman; H. J. Grabosch; A. Leich; A. Meyer; C. Rethfeldt; S. Schlenstedt; G. Barbagli; P. Pelfer; G. Anzivino; G. Maccarrone; S. de Pasquale; S. Qian; L. Votano; A. Bamberger; A. Freidhof; T. Poser; S. Söldner-Rembold; J. Schroeder; G. Theisen; T. Trefzger; N. H. Brook; P. J. Bussey; A. T. Doyle; I. Fleck; V. A. Jamieson; D. H. Saxon; M. L. Utley; A. S. Wilson; A. Dannemann; U. Holm; D. Horstmann; H. Kammerlocher; B. Krebs; T. Neumann; R. Sinkus; K. Wick; E. Badura; B. D. Burow; A. Fürtjes; L. Hagge; E. Lohrmann; J. Mainusch; J. Milewski; M. Nakahata; N. Pavel; G. Poelz; W. Schott; J. Terron; F. Zetsche; T. C. Bacon; R. Beuselinck; I. Butterworth; E. Gallo; V. L. Harris; B. H. Hung; K. R. Long; D. B. Miller; P. P. O. Morawitz; A. Prinias; J. K. Sedgbeer; A. F. Whitfield; U. Mallik; E. McCliment; M. Z. Wang; S. M. Wang; J. T. Wu; Y. Zhang; P. Cloth; D. Filges; S. H. An; S. M. Hong; S. W. Nam; S. K. Park; M. H. Suh; S. H. Yon; R. Imlay; S. Kartik; H.-J. Kim; R. R. McNeil; W. Metcalf; V. K. Nadendla; F. Barreiro; G. Cases; R. Graciani; J. M. Hernández; L. Hervás; L. Labarga; J. del Peso; J. Puga; J. F. de Trocóniz; F. Ikraiam; J. K. Mayer; G. R. Smith; F. Corriveau; D. S. Hanna; J. Hartmann; L. W. Hung; J. N. Lim; C. G. Matthews; P. M. Patel; L. E. Sinclair; D. G. Stairs; M. St. Laurent; R. Ullmann; G. Zacek; V. Bashkirov; B. A. Dolgoshein; A. Stifutkin; G. L. Bashindzhagyan; P. F. Ermolov; L. K. Gladilin; Y. A. Golubkov; V. D. Kobrin; V. A. Kuzmin; A. S. Proskuryakov; A. A. Savin; L. M. Shcheglova; A. N. Solomin; N. P. Zotov; S. Bentvelsen; M. Botje; F. Chlebana; A. Dake; J. Engelen; P. de Jong; M. de Kamps; P. Kooijman; A. Kruse; V. O'dell; A. Tenner; H. Tiecke; W. Verkerke; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg; D. Acosta; B. Bylsma; L. S. Durkin; K. Honscheid; C. Li; T. Y. Ling; K. W. McLean; W. N. Murray; I. H. Park; T. A. Romanowski; R. Seidlein; D. S. Bailey; G. A. Blair; A. Byrne; R. J. Cashmore; A. M. Cooper-Sarkar; D. Daniels; R. C. E. Devenish; N. Harnew; M. Lancaster; P. E. Luffman; L. Lindemann; J. McFall; C. Nath; A. Quadt; H. Uijterwaal; R. Walczak; F. F. Wilson; T. Yip; G. Abbiendi; A. Bertolin; R. Brugnera; R. Carlin; F. dal Corso; M. de Giorgi; U. Dosselli; S. Limentani; M. Morandin; M. Posocco; L. Stanco; R. Stroili; C. Voci; J. Bulmahn; J. M. Butterworth; R. G. Feild; B. Y. Oh; J. J. Whitmore; G. D'Agostini; M. Iori; G. Marini; M. Mattioli; A. Nigro; E. Tassi; J. C. Hart; N. A. McCubbin; K. Prytz; T. P. Shah; T. L. Short; E. Barberis; N. Cartiglia; T. Dubbs; C. Heusch; M. van Hook; B. Hubbard; W. Lockman; J. T. Rahn; H. F.-W. Sadrozinski; A. Seiden; J. Biltzinger; R. J. Seifert; A. H. Walenta; G. Zech; H. Abramowicz; G. Briskin; S. Dagan; A. Levy; T. Hasegawa; M. Hazumi; T. Ishii; M. Kuze; S. Mine; Y. Nagasawa; T. Nagira; M. Nakao; I. Suzuki; K. Tokushuku; S. Yamada

1995-01-01

278

Krypton charge exchange cross sections for Hall effect thruster models  

SciTech Connect

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{sup +} + Kr and Kr{sup 2+} + Kr cross sections. The measurements of symmetric Kr{sup +} + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr{sup 2+} + 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 Kr{sup 2+} + Kr {yields} Kr{sup +} + Kr{sup +} reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 A{sup 2} with an exception near 70-80 eV.

Hause, Michael L. [Institute for Scientific Research, Boston College, Chestnut Hill, Massachusetts 02159 (United States); Prince, Benjamin D.; Bemish, Raymond J. [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117 (United States)

2013-04-28

279

A genetic algorithm to reduce stream channel cross section data  

USGS Publications Warehouse

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.

Berenbrock, C.

2006-01-01

280

Topological Optimization of Beam Cross Section by Employing Extrusion Constraint  

NASA Astrophysics Data System (ADS)

Optimal cross-section design of beams plays a characteristic role which signifies the rigidity of the member in bending, shear and torsion load conditions. Practically modern overhead crane girders, railway bridge girders or rail tracks etc. require constant cross-section along the axial direction. Conventional topological optimization modeling procedures in such cases prove inadequate for the reason that these procedures generate non-uniform topologies along the axis of the bending member. To examine optimal topology of those structural bending members which commonly possess constant cross-section along the axis the topology optimization with extrusion constraint is more appropriate. The extrusion constraint method suggests a fresh approach to investigate optimal topologies of beam cross-section under the influence of realistic loading condition across the section at the beginning of design cycle. Presented study is focused upon the influence of various configuration and location of the load and boundary conditions on the topology of the of the beam cross-section which was not possible prior to the materialization of the extrusion or stamping constraint method. Several realistic loads and boundary conditions have been applied on the 3D beam model and optimal cross-section topologies obtained have uniform compliance history and convergent solutions. The lowest compliance criteria have been suggested to choose topologies as furthers shape and size optimization candidates during beam design process.

Zuberi, Rehan H.; Zhengxing, Zuo; Kai, Long

2010-05-01

281

Mental visualization of objects from cross-sectional images  

PubMed Central

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

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

2011-01-01

282

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)

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.

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

1997-01-01

283

Inclined Bodies of Various Cross Sections at Supersonic Speeds  

NASA Technical Reports Server (NTRS)

To aid in assessing effects of cross-sectional shape on body aerodynamics, the forces and moments have been measured for bodies with circular, elliptic, square, and triangular cross sections at Mach numbers 1.98 and 3.88. Results for bodies with noncircular cross sections have been compared with results for bodies of revolution having the same axial distribution of cross-sectional area (and, thus, the same equivalent fineness ratio). Comparisons have been made for bodies of fineness ratios 6 and 10 at angles of attack from 0 deg to about 20 deg and for Reynolds numbers, based on body length, of 4.0 x 10(exp 6) and 6.7 x 10(exp 6). The results of this investigation show that distinct aerodynamic advantages can be obtained by using bodies with noncircular cross sections. At certain angles of bank, bodies with elliptic, square, and triangular cross sections develop considerably greater lift and lift-drag ratios than equivalent bodies of revolution. For bodies with elliptic cross sections, lift and pitching-moment coefficients can be correlated with corresponding coefficients for equivalent circular bodies. It has been found that the ratios of lift and pitching-moment coefficients for an elliptic body to those for an equivalent circular body are practically constant with change in both angle of attack and Mach number. These lift and moment ratios are given very accurately by slender-body theory. As a result of this agreement, the method of NACA Rep. 1048 for computing forces and moments for bodies of revolution has been simply extended to bodies with elliptic cross sections. For the cases considered (elliptic bodies of fineness ratios 6 and 10 having cross-sectional axis ratios of 1.5 and 2), agreement of theory with experiment is very good. As a supplement to the force and moment results, visual studies of the flow over bodies have been made by use of the vapor-screen, sublimation, and white-lead techniques. Photographs from these studies are included in the report.

Jorgensen, Leland H.

1958-01-01

284

Absolute cross sections for electron scattering from furan  

NASA Astrophysics Data System (ADS)

We report results of measurements and calculations of absolute cross sections for electron scattering from furan molecules (C4H4O). 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.

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

2012-08-01

285

Electromagnetic Dissociation Cross Sections using Weisskopf-Ewing Theory  

NASA Technical Reports Server (NTRS)

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.

Adamczyk, Anne M.; Norbury, John W.

2011-01-01

286

Beam lifetimes and ionization cross sections of U28+  

NASA Astrophysics Data System (ADS)

Beam lifetimes of stored U28+ ions with energies between 10 and 180MeV/u were measured in the heavy ion synchrotron SIS18 and in the experimental storage ring (ESR) of the GSI accelerator facility. By using the internal gas jet target of the ESR, it was possible to obtain projectile ionization cross sections for collisions with H2 and N2 from the lifetime data. The experimental cross sections are compared to theoretical data predicted by the n-body classical-trajectory Monte Carlo (CTMC) method of Olson et al. and to calculations of Shevelko et al. using the LOSS-R code. In addition, both theoretical approaches are probed by using the resulting cross sections as input parameters for the STRAHLSIM code, which models the beam losses and, consequently, the lifetimes in the heavy ion synchrotron SIS18. Both the cross section measurement and the SIS18 lifetime study indicate that the LOSS-R code cross sections are in better agreement with the experimental results than the n-body CTMC calculations.

Weber, G.; Omet, C.; Dubois, R. D.; de Lucio, O.; Stöhlker, Th.; Brandau, C.; Gumberidze, A.; Hagmann, S.; Hess, S.; Kozhuharov, C.; Reuschl, R.; Spiller, P.; Spillmann, U.; Steck, M.; Thomason, M.; Trotsenko, S.

2009-08-01

287

EDDIX--a database of ionisation double differential cross sections.  

PubMed

The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure. PMID:21113060

MacGibbon, J H; Emerson, S; Liamsuwan, T; Nikjoo, H

2011-02-01

288

Lactiferous vessel detection from microscopic cross-sectional images  

NASA Astrophysics Data System (ADS)

This paper presents the methods to detect and segment lactiferous vessels or rubber latex vessels from gray scale microscopic cross-sectional images using polynomial curve-fitting with maximum and minimum stationary points. Polynomial curve-fitting is used to detect the location of lactiferous vessels from an image of a non-dyed cross-sectional slice which was taken by a digital camera through microscope lens. The lactiferous vessels are then segmented from an image using maximum and minimum stationary points with morphological closing operation. Two species of rubber trees of age between one to two years old are sampled namely, RRIM600 and RRIT251. Two data sets contain 30 microscopic cross-sectional images of one-year old rubber tree's stems from each species are used in the experiments and the results reveal that most of the lactiferous vessel areas can be segmented correctly.

Jariyawatthananon, Jirapath; Cooharojananone, Nagul; Lipikorn, Rajalida

2014-04-01

289

Nucleon-nucleon cross sections in dense nuclear matter  

SciTech Connect

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{sub 14} 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 rearrangement contribution of the three-body force is considered, which reduces the neutron and proton effective mass and suppresses the magnitude of the cross section. The presence of 'Z diagrams' in the three-body force enables us to make a comparison with the medium effects on the nucleon-nucleon cross sections obtained with the Dirac-Brueckner-Hartree-Fock approximation.

Zhang, H. F. [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Li, Z. H. [INFN-LNS, Via S. Sofia 64, I-95123 Catania (Italy); Lombardo, U. [INFN-LNS, Via S. Sofia 64, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Via A. Doria 6, I-95123 Catania (Italy); Luo, P. Y.; Zuo, W. [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China); Sammarruca, F. [Physics Department, University of Idaho, Moscow, Idaho 83844-0903 (United States)

2007-11-15

290

Dosimetry and cross section measurements at RTNS II  

SciTech Connect

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.

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

1987-01-01

291

pi+- p differential cross sections at low energies  

E-print Network

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.

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

292

K-shell photoejection cross section for neutral iron  

NASA Astrophysics Data System (ADS)

This Letter presents the first ab initio calculation, using the R-matrix method, of the cross section for photoejection of a K-shell electron from neutral iron. A 9-state target state approximation is employed, and the results are compared with recent theoretical values, namely the Hartree-Dirac-Slater method data of Verner and co-workers (1993, 1995). At the highest photon energy considered (640 Ryd), agreement is excellent. However, with decreasing photon energy the two calculations diverge, and the behaviour of the present cross section near threshold shows a rapid rise from threshold in contrast to earlier work for which the behaviour of the cross section as a function of photon energy is approximately linear.

Black, G. M.; Donnelly, D.; Bell, K. L.; Scott, M. P.; Keenan, F. P.

1998-09-01

293

Majorana Dark Matter Cross Sections with Nucleons at High Energies  

E-print Network

Non-relativistic dark matter scattering with nucleons is constrained by direct detection experiments. We use the XENON constraints on the spin-independent and spin-dependent cross section for dark matter scattering with nucleons to constrain a hypothetical Majorana fermionic dark matter particle's couplings to the Higgs boson and Z boson. In the procedure we illustrate the change in the dark matter nucleon cross section as one goes from non-relativistic, coherent scattering to relativistic, incoherent scattering. While the Z invisible decay width excludes directly couplings of dark matter to ordinary matter, by introducing a light Z' portal to the dark sector, a relatively large dark matter nucleon cross section can be preserved even with accelerator experiment constraints for dark matter with a mass of ~10 GeV

Yu Seon Jeong; C. S. Kim; Mary Hall Reno

2012-07-06

294

Inelastic cross sections for positron scattering from atomic hydrogen  

SciTech Connect

Positronium formation (Ps) cross sections for positrons impinging on atomic hydrogen were measured in the impact energy range from 13eV to 255eV at the High Intensity Positron (HIP) beam at Brookhaven National Laboratory (BNL). The Ps-formation cross section was found to rise rapidly from the threshold at 6.8eV to a maximum value of (2.98 {plus_minus} 0.18) {times} 10{sup {minus}16} cm{sup 2} for {approx} 15eV positrons. By 75eV it drops below the detection limit of 0.17 {times} 10{sup {minus}16} cm{sup 2} which is the present level of statistical uncertainty. The experiment was modified to enable the measurement of doubly differential scattering cross sections.

Weber, M.; Hofmann, A.; Raith, W.; Sperber, W. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Jacobsen, F.; Lynn, K.G. [Brookhaven National Lab., Upton, NY (United States)

1994-12-31

295

Electron impact double ionization cross sections of light elements  

NASA Astrophysics Data System (ADS)

A simple user-friendly semiempirical model is proposed to calculate electron impact double ionization cross sections of He, Li, Li+, B+, C+, C3+, O, O2+, O3+, Ne, Ne+, Ne2+, Na, Mg, Al3+, S, and Arq+ (q=0-7) targets for the incident electron energies from threshold to 106 eV. The contributions in the total double ionization cross sections from the direct double ionization and inner-shell ionization processes are taken into account on the basis of experimental data considered. The results of the present analysis are compared with the available experimental data and theoretical calculations. The model is found successful for the description of experimental cross sections. Since, this model may be a prudent selection to meet the demand level in plasma modeling due to its simple inherent structure.

Talukder, M. R.; Haque, A. K. F.; Uddin, M. A.

2009-06-01

296

Pion Total Cross Section in Nucleon - Nucleon Collisions  

NASA Technical Reports Server (NTRS)

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.

Norbury, John W.

2009-01-01

297

NC515: a new dipole cross-section for SSC  

SciTech Connect

A new dipole cross-section for SSC is outlined which has multipole coefficients of less than 1.0 x 10/sup -6/ of the dipole field (or 0.01 units) at 1.0 cm. This cross-section has four conductor blocks (three wedges, sixteen turns) in the inner layer and tow conductor blocks (one wedge, twenty turns) in the outer layer. The two layers were formed from the same types of ''partially-keystoned'' cable used in model magnets at LBL and BNL. Based on present cable design an operating field of 6.6 T at 4.34 K is chosen. The new cross-section ''NC515'' and multipoles (for ..mu..-infinite in iron) are shown.

Caspi, S.; Helm, M.; Laslett, L.J.; Taylor, C.

1986-01-01

298

Testing wave packet dynamics in computing radiative association cross sections  

NASA Astrophysics Data System (ADS)

A time-dependent wave packet method is used to compute cross sections for radiative recombination reactions using the Li(S2)+H+ ?LiH+(X?+2)+? as a test case. Cross sections are calculated through standard time-to-energy mapping of the time-dependent transition moment and a useful method is introduced to deal with the low collision energy regime. Results are in quantitative agreement over the whole energy range 10-4-5eV with previous time-independent results for the same system [I. Baccarelli, L. Andric, T. Grozdanov, and R. McCarroll, J. Chem. Phys. 117, 3013 (2002)], thereby suggesting that the method can be of help in computing radiative association cross sections for more complicated systems.

Martinazzo, Rocco; Tantardini, Gian Franco

2005-03-01

299

Lanl Neutron-Induced Fission Cross Section Measurement Program  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

300

pi+- p differential cross sections at low energies  

SciTech Connect

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.

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

301

Carbonyl sulfide isotopologues: ultraviolet absorption cross sections and stratospheric photolysis.  

PubMed

Ultraviolet absorption cross sections of the main and substituted carbonyl sulfide isotopologues were calculated using wavepacket dynamics. The calculated absorption cross section of (16)O(12)C(32)S is in very good agreement with the accepted experimental spectrum between 190 and 250 nm. Relative to (16)O(12)C(32)S, isotopic substitution shows a significant enhancement of the cross section for (16)O(13)C(32)S, a significant reduction for (18)O(12)C(32)S and (17)O(12)C(32)S and almost no change for the sulfur isotopologues (16)O(12)C(33)S, (16)O(12)C(34)S, and (16)O(12)C(36)S. The analysis of the initial wavepackets shows that these changes can be explained in terms of the change in the norm of the initial wavepacket. Implications for our understanding of the stratospheric sulfur cycle are discussed. PMID:19603991

Danielache, Sebastian O; Nanbu, Shinkoh; Eskebjerg, Carsten; Johnson, Matthew S; Yoshida, Naohiro

2009-07-14

302

Stellar neutron capture cross sections of the Ba isotopes  

NASA Astrophysics Data System (ADS)

The neutron capture cross sections of 134Ba, 135Ba, 136Ba, and 137Ba were measured in the energy range from 5 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7Li (p,n)7 Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4? barium fluoride detector. The cross section ratios were determined with an overall uncertainty of ~3%, an improvement by factors of 5 to 8 compared to existing data. Severe discrepancies were found with respect to previous results. As a new possibility in time of flight experiments, isomeric cross section ratios could be determined for 135Ba, 136Ba, and 137Ba. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 keV and 100 keV. These stellar cross sections were used in an s-process analysis. For the s-only isotopes 134Ba and 136Ba the Ns ratio was determined to 0.875+/-0.025. Hence, a significant branching of the s-process path at 134Cs can be claimed for the first time, in contrast to predictions from the classical approach. This branching yields information on the s-process temperature, indicating values around T8=2. The new cross sections are also important for the interpretation of barium isotopic anomalies, which were recently discovered in SiC grains of carbonaceous chondrite meteorites. Together with the results from previous experiments on tellurium and samarium, a general improvement of the Ns systematics in the mass range A=120-150 is achieved. This yields a more reliable separation of s- and r-process contributions for comparison with stellar observations, but reveals a 20% discrepancy with respect to the solar barium abundance.

Voss, F.; Wisshak, K.; Guber, K.; Käppeler, F.; Reffo, G.

1994-11-01

303

Neutron capture cross section standards for BNL 325, Fourth Edition  

SciTech Connect

This report evaluates the experimental data and recommends values for the thermal neutron cross sections and resonance integrals for the neutron capture reactions: /sup 55/Mn(n,..gamma..), /sup 59/Co(n,..gamma..) and /sup 197/Au(n,..gamma..). The failure of lithium and boron as standards due to the natural variation of the absorption cross sections of these elements is discussed. The Westcott convention, which describes the neutron spectrum as a thermal Maxwellian distribution with an epithermal component, is also discussed.

Holden, N.E.

1981-01-01

304

Inclusive charged particle cross sections in photoproduction at HERA  

NASA Astrophysics Data System (ADS)

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 overlinepp collisions at comparable centre-of-mass energies ?S ?p ? ?S overlinepp ? 200 GeV, and also harder than in ?p collisions at lower energies ? S?p ? 18 GeV. Results from quantum chromodynamics (QCD) calculations agree with the measured transverse momentum and pseudorapidity cross sections.

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

1994-05-01

305

Total photoproduction cross section measurement at HERA energies  

NASA Astrophysics Data System (ADS)

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 ?p total cross section has been measured by two independent methods in the ?p center of mass energy range from 90 to 290 GeV. For an average center of mass energy of 195 GeV a value of ?tot (?p) = 159 +/- 7 (stat.) +/- 20 (syst.) ?b was obtained. Supported by the Swedish Natural Science Research Council.

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

1993-01-01

306

Iterative cross section sequence graph for handwritten character segmentation.  

PubMed

The iterative cross section sequence graph (ICSSG) is an algorithm for handwritten character segmentation. It expands the cross section sequence graph concept by applying it iteratively at equally spaced thresholds. The iterative thresholding reduces the effect of information loss associated with image binarization. ICSSG preserves the characters' skeletal structure by preventing the interference of pixels that causes flooding of adjacent characters' segments. Improving the structural quality of the characters' skeleton facilitates better feature extraction and classification, which improves the overall performance of optical character recognition (OCR). Experimental results showed significant improvements in OCR recognition rates compared to other well-established segmentation algorithms. PMID:17688219

Dawoud, Amer

2007-08-01

307

MINING INTEGRAL ACTINIDES CROSS SECTIONS FROM REACTOR DATA  

SciTech Connect

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 ({approx} 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 validate reactor and criticality safety codes such as SCALE/KENO or MCNPX; and (4) analysis along multiple transmutation paths can be evaluated to show consistency.

PUIGH RJ

2009-09-11

308

Inclusive jet cross section measurement at D0  

E-print Network

We present a new preliminary measurement of the inclusive jet cross section in pp-bar collisions based on a integrated luminosity of about 0.8 fb-1. The data were acquired using the D0 detector between 2002 and 2005. Jets are reconstructed using an iterative cone algorithm with radius R_cone = 0.7. The inclusive jet cross section is presented as a function of transverse jet momentum and rapidity. Predictions from perturbative QCD in next-to-leading order, plus threshold corrections in 2-loop accuracy describe the shape in the transverse jet momentum.

M. Voutilainen

2006-09-15

309

Measurements of multiphoton action cross sections for multiphoton microscopy  

PubMed Central

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

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

2014-01-01

310

Inelastic cross sections from gamma-ray measurements  

SciTech Connect

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.

Nelson, Ronald Owen [Los Alamos National Laboratory

2010-12-06

311

Fermi energy of a metal nanowire with elliptical cross section  

NASA Astrophysics Data System (ADS)

The influence of the geometrical shape of the cross section on the energy characteristics of a metal nanowire has been investigated theoretically. The size oscillations of the Fermi energy have been calculated within the model of an infinite potential well in terms of the perturbation theory. The calculations have been carried out for Au and Al. It has been shown that the cross-sectional ellipticity with a low eccentricity can be taken into account in the first-order perturbation theory by modifying the boundary conditions for the radial wave function of electrons.

Korotun, A. V.

2014-06-01

312

Total cross section of electron scattering by fluorocarbon molecules  

NASA Astrophysics Data System (ADS)

A compact linear electron transmission apparatus was used for the measurement of the total electron scattering cross section at 4-500 eV. Total cross sections of chlorofluorocarbon (CCl2F2), hydrochlorofluorocarbon (CHClF2), perfluoropropane (C3F8), perfluoro-n-pentane (C5F12), perfluoro-n-hexane (C6F14) and perfluoro-n-octane (C8F18) were obtained experimentally and compared with the values obtained from a theoretical calculation and semi-empirical model calculation.

Yamada, T.; Ushiroda, S.; Kondo, Y.

2008-12-01

313

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

SciTech Connect

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.

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

1982-12-01

314

Direct processes effects on deuteron activation cross sections  

NASA Astrophysics Data System (ADS)

An extended analysis of reaction mechanisms involved in deuterons interaction with target nuclei from 27Al till 231Pa, at incident energies up to 60 MeV, is presented. Increased attention is devoted to direct processes, concerning the breakup, stripping, and pickup contributions to the deuteron activation cross sections. Finally, the pre-equilibrium and evaporation cross sections, corrected for the initial flux leakage towards direct processes, have completed the deuteron interaction analysis. The overall agreement of the measured data and model calculations proves the correctness of nuclear mechanism description.

Avrigeanu, M.; Avrigeanu, V.

2014-09-01

315

Cross section for {sup 246}Cm subbarrier fission  

SciTech Connect

The cross section for {sup 246}Cm fission induced by neutrons of energy in the range 0.1 eV-20 keV was measured by the neutron lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (INR, Russian Academy of Sciences, Moscow). The parameters of the resonance area and of the fission width were evaluated for several low-lying s-wave neutron resonances. The parameters of the intermediate structure in the cross section for the subbarrier fusion of {sup 246}Cm nuclei were found. The results obtained in this way were compared with available experimental data and with recommended evaluated data.

Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Samylin, B. F.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S., E-mail: shorin@ippe.r [Institute for Physics and Power Engineering (Russian Federation)

2010-10-15

316

Cross section for the subbarrier fission of {sup 244}Cm  

SciTech Connect

The cross section for {sup 244}Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective fission widths were evaluated. Also, the parameters of the intermediate structure in the cross section for the subbarrier fission of {sup 244}Cm nuclei were evaluated. The results were compared with available data and recommendations based on evaluations.

Alekseev, A. A.; Bergman, A. A.; Berlev, A. I.; Koptelov, E. A. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Samylin, B. F.; Svirin, M. I.; Trufanov, A. M.; Fursov, B. I.; Shorin, V. S., E-mail: shorin@ippe.r [Institute of Physics and Power Engineering (Russian Federation)

2010-09-15

317

Impact dynamics of granular jets with noncircular cross sections  

NASA Astrophysics Data System (ADS)

Using high-speed photography, we investigate two distinct regimes of the impact dynamics of granular jets with noncircular cross sections. In the steady-state regime, we observe the formation of thin granular sheets with anisotropic shapes and show that the degree of anisotropy increases with the aspect ratio of the jet's cross section. Our results illustrate the liquidlike behavior of granular materials during impact and demonstrate that a collective hydrodynamic flow emerges from strongly interacting discrete particles. We discuss the analogy between our experiments and those from the Relativistic Heavy Ion Collider, where similar anisotropic ejecta from a quark-gluon plasma have been observed in heavy-ion impact.

Cheng, Xiang; Gordillo, Leonardo; Zhang, Wendy W.; Jaeger, Heinrich M.; Nagel, Sidney R.

2014-04-01

318

Differential Cross Sections for Proton-Proton Elastic Scattering  

NASA Technical Reports Server (NTRS)

Proton-proton elastic scattering is investigated within the framework of the one pion exchange model in an attempt to model nucleon-nucleon interactions spanning the large range of energies important to cosmic ray shielding. A quantum field theoretic calculation is used to compute both differential and total cross sections. A scalar theory is then presented and compared to the one pion exchange model. The theoretical cross sections are compared to proton-proton scattering data to determine the validity of the models.

Norman, Ryan B.; Dick, Frank; Norbury, John W.; Blattnig, Steve R.

2009-01-01

319

Light ray tracing through a leaf cross section  

NASA Technical Reports Server (NTRS)

A light ray, incident at about 5 deg to the normal, is geometrically plotted through the drawing of the cross section of a soybean leaf using Fresnel's equations and Snell's law. The optical mediums of the leaf considered for ray tracing are: air, cell sap, chloroplast, and cell wall. The ray is also drawn through the same leaf cross section with cell wall and air as the only optical mediums. The values of the reflection and transmission found from the ray tracing tests agree closely with the experimental results obtained using a Beckman Dk-2A Spectroreflector.

Kumar, R.; Silva, L. F.

1973-01-01

320

Light ray tracing through a leaf cross section  

NASA Technical Reports Server (NTRS)

A light ray, incident at about 5 deg to the normal, is geometrically plotted through the drawing of the cross section of a soybean leaf using Fresnel's equations and Snell's law. The optical mediums of the leaf considered for ray tracing are air, cell sap, chloroplast, and cell wall. The above ray is also drawn through the same leaf cross section considering cell wall and air as the only optical mediums. The values of the reflection and transmission found from ray tracing agree closely with the experimental results obtained using a Beckman DK-2A spectroreflectometer.

Kumar, R.; Silva, L.

1973-01-01

321

Ion dipole capture cross sections at low ion and rotational energies - Comparison of integrated capture cross sections with reaction cross sections for NH3 and H2O parent-ion collisions.  

NASA Technical Reports Server (NTRS)

The numerical capture cross section is calculated from the capture ratio, defined as the fraction of trajectories reaching a prescribed minimum separation of 3 A. The calculated capture cross sections for a rotational temperature of 77 K suggest large reaction cross sections in 80 K experiments for the large dipole-moment target, methyl cyanide.

Dugan, J. V., Jr.; Canright, R. B., Jr.

1972-01-01

322

Fast Neutron Inelastic Scattering Cross Sections of URANIUM-238  

NASA Astrophysics Data System (ADS)

Neutron inelastic scattering cross sections for ('238)U levels between 680 keV and 1530 keV excitation energy have been measured in the incident neutron energy range from 0.9 to 2.2 MeV. As a highly deformed actinide nucleus, ('238)U possesses a complicated level structure and level transition properties, so the (n,n') time-of -flight (TOF) techniques were used to obtain direct level cross sections, Neutrons were generated using the ('7)Li(p,n) reaction. In order to achieve the required energy resolution of less than 15 keV the parameters of our (n,n') TOF spectrometer were optimized. Level cross sections were deduced from measured 125(DEGREES)-differential scattering cross sections. The validity of this procedure was confirmed by measuring the angular distributions for 9 levels at E(,n) = 1.5 MeV and E(,n) = 2.0 MeV, respectively. In the data analysis the additional background due to fission in ('238)U scatterer induced by fast neutron was simulated and subtracted. The TOF spectra were unfolded by using the method of response function. The correction factors of multiple scattering and neutron attenuation for disc scatterer were calculated by using analytic method coded for a small minicomputer. The excitation functions obtained were compared with our previous (n,n'(gamma)) results, with those of ORNL measurements, with ENDF/B-V evaluations, and with recent theoretical calculations.

Shao, Ji-Qun

323

Soda Lake Well Lithology Data and Geologic Cross-Sections  

SciTech Connect

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.

Faulds, James E.

2013-12-31

324

Soda Lake Well Lithology Data and Geologic Cross-Sections  

DOE Data Explorer

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.

Faulds, James E.

325

Measurement of inclusive jet cross sections in photoproduction at HERA  

NASA Astrophysics Data System (ADS)

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.

H1 Collaboration; Abt, I.; Ahmed, T.; Andreev, V.; Andrieu, B.; Appuhn, R.-D.; Arpagaus, M.; Babaev, A.; Bärwolff, H.; Bán, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bergstein, H.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besançon, M.; Biddulph, P.; Binder, E.; Bischoff, A.; Bizot, J. C.; Blobel, V.; Borras, K.; Bosetti, P. C.; Boudry, V.; Bourdarios, C.; Brasse, F.; Braun, U.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Büngener, L.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A. B.; Colombo, M.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cvach, J.; Dagoret, S.; Dainton, J. B.; Danilov, M.; Dann, A. W. E.; Dau, W. D.; David, M.; Deffur, E.; Delcourt, B.; del Buono, L.; Devel, M.; de Roeck, A.; Dingus, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Drescher, A.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Ebbinghaus, R.; Eberle, M.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellis, N. N.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Fensome, I. F.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Flauger, W.; Fleischer, M.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Fuhrmann, P.; Gabathuler, E.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gellrich, A.; Gennis, M.; Genzel, H.; Gerhards, R.; Godfrey, L.; Goerlach, U.; Goerlich, L.; Goldberg, M.; Goodall, A. M.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Greif, H.; Grindhammer, G.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Handschuh, D.; Hanlon, E. M.; Hapke, M.; Harjes, J.; Haydar, R.; Haynes, W. J.; Heatherington, J.; Hedberg, V.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herma, R.; Herynek, I.; Hildesheim, W.; Hill, P.; Hilton, C. D.; Hladký, J.; Hoeger, K. C.; Huet, Ph.; Hufnagel, H.; Huot, N.; Ibbotson, M.; Itterbeck, H.; Jabiol, M.-A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Jansen, T.; Jönsson, L.; Johannsen, K.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kasarian, S.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Kaufmann, H. H.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Ko, W.; Köhler, T.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kur?a, T.; Kurzhöfer, J.; Kuznik, B.; Lamarche, F.; Lander, R.; Landon, M. P. J.; Lange, W.; Langkau, R.; Lanius, P.; Laporte, J. F.; Lebedev, A.; Leuschner, A.; Leverenz, C.; Levonian, S.; Lewin, D.; Ley, Ch.; Lindner, A.; Lindström, G.; Linsel, F.; Lipinski, J.; Loch, P.; Lohmander, H.; Lopez, G. C.; Lüers, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; 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.; Mikocki, S.; Milone, V.; Monnier, E.; Moreau, F.; Moreels, J.; Morris, J. V.; Müller, K.; Murín, P.; Murray, S. A.; Nagovizin, V.; Naroska, B.; Naumann, Th.; Newton, D.; Neyret, D.; Nguyen, H. K.; Niebergall, F.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg, M.; Oberlack, H.; Obrock, U.; Olsson, J. E.; Orenstein, S.; Ould-Saada, F.; Pascaud, C.; Patel, G. D.; Peppel, E.; Peters, S.; Phillips, H. T.; Phillips, J. C.; Pichler, Ch.; Pilgram, W.; Pitzl, D.; Prell, S.; Prosi, R.; Rädel, G.; Raupach, F.; Rauschnabel, K.; Reimer, P.; Ribarics, P.; Riech, V.; Riedlberger, J.; Riess, S.; Rietz, M.; Robertson, S. M.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rudowicz, M.; Ruffer, M.; Rusakov, S.; Rybicki, K.; Sahlmann, N.; Sanchez, E.; Sankey, D. P. C.; Savitsky, M.; Schacht, P.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmitz, W.; Schröder, V.; Schulz, M.; Schwind, A.; Scobel, W.; Seehausen, U.; Sell, R.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Shtarkov, L. N.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorn, I. O.; Smirnov, P.; Smith, J. R.; Smolik, L.; Soloviev, Y.; Spitzer, H.; Staroba, P.; Steenbock, M.; Steffen, P.; Steinberg, R.; Stella, B.; Stephens, K.; Stier, J.; Stösslein, U.; Strachota, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Taylor, R. E.; Tchernyshov, V.; Thiebaux, C.; Thompson, G.; Tichomirov, I.; Truöl, P.; Turnau, J.; Tutas, J.; Urban, L.; Usik, A.; Valkar, S.; Valkarova, A.; Vallée, C.; van Esch, P.

1993-09-01

326

Measurement of inclusive jet cross sections in photoproduction at HERA  

Microsoft Academic Search

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.

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

327

Propagation of sound waves in tubes of noncircular cross section  

NASA Technical Reports Server (NTRS)

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.

Richards, W. B.

1986-01-01

328

Loneliness Predicts Reduced Physical Activity: Cross-Sectional & Longitudinal Analyses  

Microsoft Academic Search

Objective: To determine cross-sectional and prospective associations between loneliness and physical activity, and to evaluate the roles of social control and emotion regulation as mediators of these associations. Design: A population-based sample of 229 White, Black, and Hispanic men and women, age 50 to 68 years at study onset, were tested annually for each of 3 years. Main Outcome Measures:

Louise C. Hawkley; Ronald A. Thisted; John T. Cacioppo

2009-01-01

329

Absolute cross sections for elastic electron scattering from 3-hydroxytetrahydrofuran  

NASA Astrophysics Data System (ADS)

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).

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

2008-10-01

330

Learning of Cross-Sectional Anatomy Using Clay Models  

NSDL National Science Digital Library

This article describes the effect of adding clay modeling to a gross anatomy and neuro anatomy course. The purpose of adding the clay modeling was to assist students with gaining a greater understanding of cross sectional anatomy and to compare these models to CT and MRI scans. Outcomes of the positive effect of clay modeling are explained.

2009-07-27

331

Nuclear Science and Technology, November 2000. NEUTRON CROSS SECTION EVALUATIONS  

E-print Network

Nuclear Science and Technology, November 2000. 1 NEUTRON CROSS SECTION EVALUATIONS FOR 238 U UP and Power Engineering, 249020 Obninsk, Russia A.Ventura ENEA, Nuclear Data Center and INFN, Bologna Section of the statistical description that includes direct, pre-equilibrium and equilibrium mechanisms of nuclear reactions

332

Econometric Analysis of Cross Section and Panel Data  

Microsoft Academic Search

This graduate text provides an intuitive but rigorous treatment of contemporary methods used in microeconometric research. The book makes clear that applied microeconometrics is about the estimation of marginal and treatment effects, and that parametric estimation is simply a means to this end. It also clarifies the distinction between causality and statistical association. The book focuses specifically on cross section

Jeffrey M. Wooldridge

2002-01-01

333

Measurements of absolute single differential cross section (SDCS)  

E-print Network

Measurements of absolute single differential cross section (SDCS) [Left] and percentage energy res and a resistive anode encoder are presented. A four­element lens mounted at the entrance of the analyser, provides using ion­optics program SIMION6.0 in­ dicates improved focusing properties for this off­ center

Zouros, Theo

334

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 ... Logical Images, Inc. I n the areas of skin health and skin diseases, the NIH's National Institute ...

335

45. Cross Section through the Power House, from Construction Drawing ...  

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

45. Cross Section through the Power House, from Construction Drawing 2042-F-23, entitled General Arrangement of Power Plant, Sections. (Original drawing, in the possession of Wyre Dick and Company, Livingston, New Jersey.) - Central Railroad of New Jersey, Engine Terminal, Jersey City, Hudson County, NJ

336

44. Cross section of the Blacksmith Shop from Construction Drawing ...  

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

44. Cross section of the Blacksmith Shop from Construction Drawing 2042-F-15, entitled Machine and Blacksmith Shop; Plan, Elevations, and Sections. (Original drawing, in the possession of Wyre Dick and Company, Livingston, New Jersey.) - Central Railroad of New Jersey, Engine Terminal, Jersey City, Hudson County, NJ

337

Phenomenology of SIDIS unpolarized cross sections and azimuthal asymmetries  

E-print Network

I review the phenomenology of unpolarized cross sections and azimuthal asymmetries in semi-inclusive deeply inelastic scattering (SIDIS). The general theoretical framework is presented and the validity of the Gaussian model is discussed. A brief account of the existing analyses is provided.

Vincenzo Barone

2012-03-28

338

Differential cross section for the double photoionization of Mg  

NASA Astrophysics Data System (ADS)

The time-dependent close-coupling (TDCC) method is used to calculate the energy and angle triple differential cross section for the double photoionization of Mg(3{{s}2}) at a photon energy of 55.49 eV to compare with recent converged close-coupling (CCC) calculations and in support of recent experiments at ELETTRA. Comparisons are made between the TDCC, CCC, and experimental results for equal energy sharing at scattering angles of 0{}^\\circ , 30{}^\\circ , and 60{}^\\circ , and for unequal energy sharing at 0{}^\\circ and 30{}^\\circ . Comparisons are made between the TDCC and CCC results for equal and unequal energy sharing at 90{}^\\circ . In addition, TDCC, CCC, and experimental results are compared for complex scattering amplitudes and the TDCC method is used to calculate single energy differential cross sections at photon energies of 30, 35, 40, 45, and 55.49 eV. Although there are scattering angles in the triple differential cross sections at 55.49 eV at which the TDCC, CCC, and experimental results are quite different, the overall agreement between the theories and experiment is reasonable for such small cross sections.

Abdel-Naby, Shahin A.; Pindzola, M. S.; Colgan, J.

2015-01-01

339

Fermion absorption cross section of a Schwarzschild black hole  

E-print Network

We study the absorption of massive spin-half particles by a small Schwarzschild black hole by numerically solving the single-particle Dirac equation in Painleve-Gullstrand coordinates. We calculate the absorption cross section for a range of gravitational couplings Mm/m_P^2 and incident particle energies E. At high couplings, where the Schwarzschild radius R_S is much greater than the wavelength lambda, we find that the cross section approaches the classical result for a point particle. At intermediate couplings we find oscillations around the classical limit whose precise form depends on the particle mass. These oscillations give quantum violations of the equivalence principle. At high energies the cross section converges on the geometric-optics value of 27 \\pi R_S^2/4, and at low energies we find agreement with an approximation derived by Unruh. When the hole is much smaller than the particle wavelength we confirm that the minimum possible cross section approaches \\pi R_S^2/2.

Chris Doran; Anthony Lasenby; Sam Dolan; Ian Hinder

2005-03-04

340

4He(?,p?-) Cross Section Around ?(1236)  

NASA Astrophysics Data System (ADS)

The cross section of the reaction 4He+?-->p+?-+(ppn) has been measured in the region of the first resonance for various values of the recoil momentum. An anomaly is observed for high values of this momentum and a tentative explanation is suggested.

Argan, P. E.; Audit, G.; de Botton, N.; Laget, J.-M.; Martin, J.; Schuhl, C.; Tamas, G.

1972-10-01

341

Uptake of atmospheric molecules by ice nanoparticles: pickup cross sections.  

PubMed

Uptake of several atmospheric molecules on free ice nanoparticles was investigated. Typical examples were chosen: water, methane, NO(x) species (NO, NO(2)), hydrogen halides (HCl, HBr), and volatile organic compounds (CH(3)OH, CH(3)CH(2)OH). The cross sections for pickup of these molecules on ice nanoparticles (H(2)O)(N) with the mean size of N?260 (diameter ~2.3 nm) were measured in a molecular beam experiment. These cross sections were determined from the cluster beam velocity decrease due to the momentum transfer during the pickup process. For water molecules molecular dynamics simulations were performed to learn the details of the pickup process. The experimental results for water are in good agreement with the simulations. The pickup cross sections of ice particles of several nanometers in diameter can be more than 3 times larger than the geometrical cross sections of these particles. This can have significant consequences in modelling of atmospheric ice nanoparticles, e.g., their growth. PMID:22830699

Lengyel, J; Ko?išek, J; Poterya, V; Pysanenko, A; Svr?ková, P; Fárník, M; Zaouris, D K; Fedor, J

2012-07-21

342

Natural critical cross sections and modes of a conical waveguide  

Microsoft Academic Search

The propagation characteristics of electromagnetic waveguides guided by a conical waveguide are analyzed, taking into account field behavior in the vicinity of natural critical cross sections. It is shown that each natural mode of the waveguide corresponds to a natural caustic with a natural equivalent surface current (magnetic in the case of Emn modes and electric in the case of

V. N. Mitrokhin

1986-01-01

343

Extraction of Neutrino Flux from the Inclusive Muon Cross Section  

E-print Network

We have studied a method to extract neutrino flux from the data of neutrino-nucleus reaction by using maximum entropy method. We demonstrate a promising example to extract neutrino flux from the inclusive cross section of muon production without selecting a particular reaction process such as quasi-elastic nucleon knockout.

Murata, Tomoya

2015-01-01

344

Lava flow in tubes with elliptical cross sections  

Microsoft Academic Search

We develop a model of lava flow in a cylindrical tube with elliptical cross section. The lava is considered an isothermal, incompressible Newtonian fluid. We solve analytically the steady-state Navier–Stokes equation under a constant driving force, given by the component of gravity along the axis of the tube and obtain the velocity and stress field components in the fluid. The

Michele Dragoni; Stefano Santini

2007-01-01

345

Cross-Sectional Analyses of Climate Change Impacts  

Microsoft Academic Search

The authors explore the use of cross-sectional analysis to measure the impacts of climate change on agriculture. The impact literature, using experiments on crops in laboratory settings combined with simulation models, suggests that agriculture will be strongly affected by climate change. The extent of these effects varies by country and region. Therefore, local experiments are needed for policy purposes, which

Robert Mendelsohn; Ariel Dinar; Alan Basist; Pradeep Kurukulasuriya; Mohamed Ihsan Ajwad; Felix Kogan; Claude Williams

2004-01-01

346

11. Photograph of a line drawing. 'CROSS SECTION OF GAS ...  

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

11. Photograph of a line drawing. 'CROSS SECTION OF GAS PRODUCER.' From George R. Cooper (Wilputte Corporation). 'Operating Overview of a Producer Gas Plant (12 Machines) at Kingsport, Tennessee.' Presented at the Fifth Annual International Conference on Coal Gasification, Liquefaction and Conversion to Electricity. University of Pittsburgh, August 2, 1978. - Holston Army Ammunition Plant, Producer Gas Plant, Kingsport, Sullivan County, TN

347

12. DETAIL VIEW OF CROSS SECTION OF STRUCTURE, SHOWING THE ...  

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

12. DETAIL VIEW OF CROSS SECTION OF STRUCTURE, SHOWING THE WIDTH OF THE FACINGS AND BACKINGS THAT FORMED THE BASE OF THE WALL AT THE WESTERN END, LOOKING NORTHEAST - Rock Wall, North side of Battle Creek Canyon, Shingletown, Shasta County, CA

348

On the interweaving of partial cross sections of different parity  

NASA Technical Reports Server (NTRS)

Partial cross sections of definite parity, calculated for electronic-rotational energy transfer in the F +H2 collision system, interweave with increasing total angular momentum J. An explanation, in terms of diabatic curve crossings induced by the centrifugal potential in the body-fixed coordinate system, predicts the interweaving to occur only in systems having half-integer J.

Devries, P. L.; George, T. F.

1979-01-01

349

Electron Impact Ionization Cross Sections of n-decane  

NASA Astrophysics Data System (ADS)

The ionization and dissociation of hydrocarbon fuels with various plasma excitation schemes including pulsed high E/n discharges have been proposed to alleviate the problem of ignition in supersonic flow combustors and operations at high altitudes. The fuel which is also used for cooling, must not pyrolyse at operational temperatures. We have examined the electron ionization collision processes in n-decane using high resolution Fourier transform mass spectrometry that permits measurements of the 24 ions with cross sections larger than 10-19cm2. These generally fall into two broad categories: those with five or more carbon atoms whose ionization cross sections rise rapidly and essentially saturate within twice the appearance potential and those with four carbon atoms and less whose cross sections rise more gradually and are only saturating at energies above 70 eV. The total ionization cross section is large, rising to 7x10-16cm2. Studies were made with deuterated samples to distinguish the potential mechanisms in fragment ion induced dissociation of the parent gas. The results are compared with similar data for octane.

Jiao, Charles; Dejoseph, Charles; Garscadden, Alan

2001-10-01

350

Predictions of diffractive cross sections in proton-proton collisions  

SciTech Connect

We review our pre-LHC predictions of the total, elastic, total-inelastic, and diffractive components of proton-proton cross sections at high energies, expressed in the form of unitarized expressions based on a special parton-model approach to diffraction employing inclusive proton parton distribution functions and QCD color factors and compare with recent LHC results.

Goulianos, Konstantin [Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)

2013-04-15

351

CSM RCS Design Considerations and Failure Modes  

NASA Technical Reports Server (NTRS)

Objectives include: a) Define major Command and Service Module (CSM) design considerations; b) List Command Module (CM) RCS failures and lessons learned; and c) List Service Module (SM) RCS failures and lessons learned.

Interbartolo, Michael

2009-01-01

352

Erratum: Photoionization Cross Sections of He and H2  

NASA Astrophysics Data System (ADS)

In the paper ``Photoionization Cross Sections of He and H2'' by M. Yan, H. R. Sadeghpour, and A. Dalgarno (ApJ, 496, 1044 [1998]), the analytic representation of the H2 photoionization cross sections (eqs. [17]-[19]) is given incorrectly. The cross sections for H2 may be represented analytically by ?H2(E)=107(1-197.448x-0.5+ 438.823x-1-260.481x-1.5+17.915x-2) barns for 15.485 eV. The sum rules and the tabulated photoionization cross sections in Tables 6 and 7 are correct. The errors were drawn to our attention by the paper of J. Wilms, A. Allen, and R. McCray (ApJ, 542, 914 [2000]). We point out that our recommended cross sections are constructed from the best available experimental and calculated data and modified to ensure that several sum rules are satisfied and to conform to the correct physical high-energy limit. We emphasize that the asymptotic ratio of the nonrelativistic photoionization cross sections of H2 and H is given exactly as (?H2)/ (?H) =4?, where is the delta function matrix element at the position of nucleus a for electron 1. The numerical value of the ratio of cross sections is ?H2/ ?H=2.833 at high energies. As noted by us and by Wilms, Allen, and McCray, where molecular hydrogen contributes to the total photoabsorption, this excess of the ratio over 2 can be important.

Yan, M.; Sadeghpour, H. R.; Dalgarno, A.

2001-10-01

353

Absolute photoionization cross-section of the methyl radical.  

SciTech Connect

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.

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

2008-01-01

354

A radar-echo model for Mars  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

355

Partial ionization cross-sections of acetone and 2-butanone  

NASA Astrophysics Data System (ADS)

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.

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

2008-06-01

356

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

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

357

Multiphoton absorption cross section and virtual-state spectroscopy for the entangled n-photon state  

E-print Network

Multiphoton absorption cross section and virtual-state spectroscopy for the entangled n-photon absorption cross sections are also obtained. The absorption cross sections exhibit a linear dependence states involved in the interaction from the absorption cross section measured as a function of path delay

Teich, Malvin C.

358

Orbiter OMS and RCS technology  

NASA Technical Reports Server (NTRS)

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.

Boudreaux, R. A.

1982-01-01

359

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

E-print Network

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

Miami, University of

360

Accurate Development of Thermal Neutron Scattering Cross Section Libraries  

SciTech Connect

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.

Hawari, Ayman; Dunn, Michael

2014-06-10

361

Electromagnetic analysis of cylindrical cloaks of an arbitrary cross section.  

PubMed

We extend the design of radially symmetric invisibility cloaks through transformation optics as proposed by Pendry et al. [Science 312, 1780 (2006)] to coated cylinders of an arbitrary cross section. The validity of our Fourier-based approach is confirmed by both analytical and numerical results for a cloak displaying a non-convex cross section of varying thickness. In the former case, we evaluate the Green's function of a line source in the transformed coordinates. In the latter case, we implement a full-wave finite-element model for a cylindrical antenna radiating a p-polarized electric field in the presence of a F-shaped lossy object surrounded by the cloak. PMID:18628805

Nicolet, André; Zolla, Frédéric; Guenneau, Sébastien

2008-07-15

362

Secondary Flows in Curved Rectangular Ducts with Diminishing Cross Section  

NASA Astrophysics Data System (ADS)

Secondary flows in curved rectangular ducts with diminishing cross sections are numerically studied. Development of secondary flow in curved rectangular regular cross-sectional area duct is studied using an improved finite difference scheme for solving parabolized Navier-Stokes equations is presented. This scheme has its origin in the work of Briley, which is based on classical ADI method to march the solution in the streamwise direction. With some modifications, it is shown in the present work that the stability of this scheme is greatly enhanced. Its applicability is considerably increased. Results with various sb. and sa for two different aspect ratio are given. Note the parameters asa and bsb, where sa is scaling factor for the width of the duct sb is scaling factor for the height of the duct, respectively. Dean number of 54 is used for the comparisons.

Darus, Amer Nordin; Fatt, Y. Y.

2010-06-01

363

Elastic cross sections for electron scattering from iodomethane  

NASA Astrophysics Data System (ADS)

Experimental results are reported for elastic differential and integral cross sections for electrons scattering from iodomethane (CH3I). These measurements were made at seven incident electron energies in the range 5-50 eV, with a scattered electron angular range of 20°-135°. Corresponding calculations using the independent atom method plus screened additivity rule (IAM-SCAR), both with and without a dipole correction, are also reported as a part of this study. Where possible, comparison is made to the only other set of experimental results available in the literature (Kato et al 2010 J. Chem. Phys. 132 074309) and to calculated cross sections from the Schwinger multichannel approach at the static exchange level (Natalense et al 2001 Braz. J. Phys. 31 15). In general, good agreement is found between the present measurements and IAM-SCAR computations, and between our results and the earlier investigations.

Hargreaves, L. R.; Brunton, J. R.; Prajapati, A.; Hoshino, M.; Blanco, F.; García, G.; Buckman, S. J.; Brunger, M. J.

2011-02-01

364

Absolute measurements of chlorine Cl+ cation single photoionization cross section  

NASA Astrophysics Data System (ADS)

The photoionization of Cl+ leading to Cl2+ was measured in the photon energy range of 19.5-28.0 eV. A spectrum with a photon energy resolution of 15 meV normalized to absolute cross-section measurements is presented. The measurements were carried out by merging a Cl+ ion beam with a photon beam of highly monochromatic synchrotron radiation at the Advanced Light Source at Lawrence Berkeley National Laboratory. The measured photoionization of Cl+ consists of several autoionization resonances surperimposed on the direct photoionization signal. Most of the prominent resonances are assigned to members of Rydberg series originating from the singlet ground state and from metastable triplet levels within the ground-state configuration of Cl+. The direct ionization cross section is no larger than 12 Mb.

Hernández, E. M.; Juárez, A. M.; Kilcoyne, A. L. D.; Aguilar, A.; Hernández, L.; Antillón, A.; Macaluso, D.; Morales-Mori, A.; González-Magaña, O.; Hanstorp, D.; Covington, A. M.; Davis, V.; Calabrese, D.; Hinojosa, G.

2015-01-01

365

Elastic breakup cross sections of well-bound nucleons  

NASA Astrophysics Data System (ADS)

The 9Be(28Mg,27Na ) one-proton removal reaction with a large proton separation energy of Sp(28Mg ) =16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the removal of more weakly bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

Wimmer, K.; Bazin, D.; Gade, A.; Tostevin, J. A.; Baugher, T.; Chajecki, Z.; Coupland, D.; Famiano, M. A.; Ghosh, T. K.; Grinyer, G. F.; Howard, M. E.; Kilburn, M.; Lynch, W. G.; Manning, B.; Meierbachtol, K.; Quarterman, P.; Ratkiewicz, A.; Sanetullaev, A.; Showalter, R. H.; Stroberg, S. R.; Tsang, M. B.; Weisshaar, D.; Winkelbauer, J.; Winkler, R.; Youngs, M.

2014-12-01

366

Hadronic Cross Section Measurement at Bes-Iii  

NASA Astrophysics Data System (ADS)

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.

Schumann, Sven

2014-12-01

367

State-selective cross sections of multiple photoionization in Ne  

SciTech Connect

Valence double photoionization of Ne atom has been investigated by multielectron spectroscopy. Complete information on energy correlation between ejected electrons allows the identification of Ne{sup 2+} final states and their formation mechanism. In addition to simultaneous two-electron emission from the valence shells, indirect processes mediated by singly charged excited states have been observed. We have first obtained direct double-photoionization cross sections state-selectively in a wide photon energy region, by evaluating the contributions of the indirect processes. We have also applied the coincidence spectroscopy to three-electron emission from the valence shells. Even in the three-electron emission, the coincidence analysis enables to observe individual Ne{sup 3+} final states related to the triple-photoionization process and to obtain the state-selective cross sections.

Kaneyasu, T.; Hikosaka, Y.; Shigemasa, E.; Penent, F.; Lablanquie, P.; Aoto, T.; Ito, K. [UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); LCP-MR, Universite Pierre et Marie Curie-Paris 6 and CNRS (UMR 7614), 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Photon Factory, Institute of Materials Structure Science, Oho, Tsukuba 305-0801 (Japan)

2007-07-15

368

Neutrino versus antineutrino cross sections and CP violation  

E-print Network

We discuss the nuclear interactions of neutrinos versus those of antineutrinos, a relevant comparison for CP violation experiments in the neutrino sector. We consider the MiniBooNE quasielastic-like double differential neutrinos and antineutrinos cross sections which are flux dependent and hence specific to the MiniBooNE set-up. We combine them introducing their sum and their difference. We show that the last combination can bring a general information, which can be exploited in other experiments, on the nuclear matrix elements of the axial vector interference term. Our theoretical model reproduces well the two cross sections combinations. This confirms the need for a sizeable multinucleon component in particular in the interference term.

Ericson, M

2015-01-01

369

Elastic breakup cross sections of well-bound nucleons  

E-print Network

The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the re- moval of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

K. Wimmer; D. Bazin; A. Gade; J. A. Tostevin; T. Baugher; Z. Chajecki; D. Coupland; M. A. Famiano; T. K. Ghosh; G. F. Grinyer M. E. Howard; M. Kilburn; W. G. Lynch; B. Manning; K. Meierbachtol; P. Quarterman; A. Ratkiewicz; A. Sanetullaev; R. H. Showalter; S. R. Stroberg; M. B. Tsang; D. Weisshaar; J. Winkelbauer; R. Winkler; M. Youngs

2014-12-07

370

NIFFTE Time Projection Chamber for Fission Cross Section Measurements  

NASA Astrophysics Data System (ADS)

In order to design safer and more efficient Generation IV nuclear reactors, more accurate knowledge of fission cross sections is needed. The goal of the Time Projection Chamber (TPC) used by the Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration is to measure the cross sections of several fissile materials to within 1% uncertainty. The ability of the TPC to produce 3D ``pictures'' of charged particle trajectories will eliminate unwanted alpha particles in the data. Another important source of error is the normalization of data the U-235 standard. NIFFTE will use the H(n,n)H reaction instead, which is known to better than 0.2%. The run control and monitoring system will eventually allow for nearly complete automation and off-site monitoring of the experiment. This presentation will cover the need for precision measurements and an overview of the experiment.

Castillo, Ryan

2011-10-01

371

Electron scattering from pyrazine: elastic differential and integral cross sections.  

PubMed

We report on new measurements for elastic electron scattering from pyrazine. Absolute differential cross sections (DCSs) at seven discrete energies in the range 3-50 eV, and over the scattered electron angular range 10°-129°, were determined using a crossed electron-molecular beam spectrometer in conjunction with the well-established relative flow technique. Integral elastic cross sections were subsequently derived from those DCS data at each energy. Where possible comparison between the present results and those from sophisticated Schwinger multichannel and R-matrix computations is made, with generally quite good quantitative accord being found. Finally, in order to better study some of the rich resonance structure predicted by theory, results from elastic electron excitation functions are presented. PMID:23206003

Palihawadana, P; Sullivan, J P; Buckman, S J; Brunger, M J

2012-11-28

372

Turbulent combustion flow through variable cross section channel  

SciTech Connect

The object of this study is to develop a new evolutionary numerical method for solving direct task of Laval nozzle, which provides non-iterative calculations of chemical reacting turbulent flows with detailed kinetic chemistry. The numerical scheme of fourth order along the normal coordinate and second order along the streamwise one is derived for calculation of difference-differential equations of the second order and the first order. Marching method provides the possibility of computing field flow in subsonic section of nozzle and near an expansion. Critical mass consumption is calculated with controlled accuracy. After critical cross section of nozzle a combined marching method with global iterations over axial pressure (only) makes it possible to overcome ill posedness of mixed supersonic flow and calculate the whole flow field near and after critical cross section. Numerical results are demonstrated on turbulent burning hydrogen-oxygen flow through Laval nozzle with curvature of wall K{sub w} = 0.5.

Rogov, B.V.; Sokolova, I.A.

1999-07-01

373

Probing neutron-skin thickness with total reaction cross sections  

E-print Network

We analyze total reaction cross sections, $\\sigma_R$, for exploring their sensitivity to the neutron-skin thickness of nuclei. We cover 91 nuclei of O, Ne, Mg, Si, S, Ca, and Ni isotopes. The cross sections are calculated in the Glauber theory using the density distributions obtained with the Skyrme-Hartree-Fock method in 3-dimensional coordinate space. Defining a reaction radius, $a_R=\\sqrt{\\sigma_R/\\pi}$, to characterize the nuclear size and target (proton or $^{12}$C) dependence, we find an empirical formula for expressing $a_R$ with the point matter radius and the skin thickness, and assess two practical ways of determining the skin thickness from proton-nucleus $\\sigma_R$ values measured at different energies or from $\\sigma_R$ values measured for different targets.

Horiuchi, W; Inakura, T

2014-01-01

374

Inclusive parton cross sections in photoproduction and photon structure  

NASA Astrophysics Data System (ADS)

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 GeV 2.

Ahmed, T.; Aid, S.; Andreev, V.; Andrieu, B.; Appuhn, R.-D.; Arpagaus, M.; Babaev, A.; Baehr, J.; Bán, J.; Ban, Y.; Baranov, P.; Barrelet, E.; Bartel, W.; Barth, M.; Bassler, U.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besançon, M.; Beyer, R.; Biddulph, P.; Bispham, P.; Bizot, J. C.; Blobel, V.; Borras, K.; Botterweck, F.; Boudry, V.; Braemer, A.; Brasse, F.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Brune, C.; Buchholz, R.; Büngener, L.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Burton, M.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Charlet, M.; Clarke, D.; Clegg, A. B.; Clerbaux, B.; Colombo, M.; Contreras, J. G.; Cormack, C.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cussans, D. G.; Cvach, J.; Dagoret, S.; Dainton, J. B.; Dau, W. D.; Daum, K.; David, M.; Delcourt, B.; Del Buono, L.; De Roeck, A.; De Wolf, E. A.; Di Nezza, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Droutskoi, A.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Ehrlichmann, H.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Erdmann, W.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Fleischer, M.; Flieser, M.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Gabathuler, E.; Gabathuler, K.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gebauer, M.; Gellrich, A.; Genzel, H.; Gerhards, R.; Goerlach, U.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goldner, D.; Gonzalez-Pineiro, B.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Grindhammer, G.; Gruber, A.; Gruber, C.; Haack, J.; Haidt, D.; 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.; Hladký, J.; Hoeger, K. C.; Höppner, M.; Horisberger, R.; Hudgson, V. L.; Huet, Ph.; Hütte, M.; Hufnagel, H.; Ibbotson, M.; Itterbeck, H.; Jabiol, M.-A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Janoth, J.; Jansen, T.; Jönsson, L.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kant, D.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Katzy, J.; Kaufmann, H. H.; Kazarian, S.; Kenyon, I. R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Ko, W.; Köhler, T.; Köhne, J. H.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krämerkämper, T.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Krüner-Marquis, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kur?a, T.; Kurzhöfer, J.; Kuznik, B.; Lacour, D.; Lamarche, F.; Lander, R.; Landon, M. P. J.; Lange, W.; Lanius, P.; Laporte, J.-F.; Lebedev, A.; Leverenz, C.; Levonian, S.; Ley, Ch.; Lindner, A.; Lindström, G.; Link, J.; Linsel, F.; Lipinski, J.; List, B.; Lobo, G.; Loch, P.; Lohmander, H.; Lomas, J.; Lopez, G. C.; Lubimov, V.; Lüke, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Mara?ek, R.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; Martyn, H.-U.; Martyniak, J.; Masson, S.; Mavroidis, T.; 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.; Müller, G.; Müller, K.; Murín, P.; Nagovizin, V.; Nahnhauer, R.; Naroska, B.; Naumann, Th.; Newman, P. R.; Newton, D.; Neyret, D.; Nguyen, H. K.; Nicholls, T. C.; Niebergall, F.; Niebuhr, C.; Niedzballa, Ch.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg-Werther, M.; Oakden, M.; Oberlack, H.; Obrock, U.; Olsson, J. E.; Ozerov, D.; Panaro, E.; Panitch, A.; Pascaud, C.; Patel, G. D.; Peppel, E.; Perez, E.; Phillips, J. P.; Pichler, Ch.; Pieuchot, A.; Pitzl, D.; Pope, G.; Prell, S.; Prosi, R.; Rabbertz, K.; Rädel, G.; Raupach, F.; Reimer, P.; Reinshagen, S.; Ribarics, P.; Rick, H.; Riech, V.; Riedlberger, J.; Riess, S.; Rietz, M.; Rizvi, E.; Robertson, S. M.; Robmann, P.; Roloff, H. E.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rüter, K.; Rusakov, S.; Rybicki, K.; Rylko, R.; Sahlmann, N.; Salesch, S. G.; Sanchez, E.; Sankey, D. P. C.; Schacht, P.; Schiek, S.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmidt, G.; Schöning, A.; Schröder, V.; Schuhmann, E.; Schwab, B.; Schwind, A.; Sefkow, F.; Seidel, M.; Sell, R.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Shtarkov, L. N.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorn, I. O.; Smirnov, P.

1995-02-01

375

Measuring the hadronic cross section via radiative return  

Microsoft Academic Search

Recently it has been demonstrated that particle factories, such as DA?NE and PEP-II, operating at fixed center-of-mass energies, are able to measure hadronic cross sections as a function of the hadronic system energy using the radiative return. This paper is an experimental overview of the progress in this area. Preliminary results from KLOE for the process e+e? ? ?? ?

A. Aloisio; F. Ambrosino; A. Antonelli; M. Antonelli; C. Bacci; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; S. A. Bulychjov; R. Caloi; P. Campana; G. Capon; G. Carboni; M. Casarsa; V. Casavola; G. Cataldi; F. Ceradini; F. Cervelli; F. Cevenini; G. Chiefari; P. Ciambrone; S. Conetti; E. De Lucia; G. De Robertis; P. De Simone; G. De Zorzi; S. Dell'Agnello; A. Denig; A. di Domenico; C. di Donato; S. Di Falco; A. Doria; M. Dreucci; O. Erriquez; A. Farilla; G. Felici; A. Ferrari; M. L. Ferrer; G. Finocchiaro; C. Forti; A. Franceschi; P. Franzini; C. Gatti; P. Gauzzi; S. Giovannella; E. Gorini; F. Grancagnolo; E. Graziani; S. W. Han; M. Incagli; L. Ingrosso; W. Kluge; C. Kuo; V. Kulikov; F. Lacava; G. Lanfranchi; J. Lee-Franzini; D. Leone; F. Lu; M. Martemianov; M. Matsyuk; W. Mei; L. Merola; R. Messi; S. Miscetti; M. Moulson; S. Müller; F. Murtas; M. Napolitano; A. Nedosekin; F. Nguyen; M. Palutan; L. Paoluzi; E. Pasqualucci; L. Passalacqua; A. Passeri; V. Patera; E. Petrolo; L. Pontecorvo; M. Primavera; F. Ruggieri; P. Santangelo; E. Santovetti; G. Saracino; R. D. Schamberger; B. Sciascia; A. Sciubba; F. Scuri; I. Sfiligoi; T. Spadaro; E. Spiriti; G. L. Tong; L. Tortora; E. Valente; P. Valente; B. Valeriani; G. Venanzoni; S. Veneziano; A. Ventura; G. Xu; G. W. Yu

2003-01-01

376

L-X-ray production cross sections by positrons  

NASA Astrophysics Data System (ADS)

The L-shell X-ray production cross sections for Ag, In and Sn by positron impact have been calculated with two methods based on classical mechanics, i.e. the binary-encounter approximation and the classical trajectory Monte Carlo method. The results are compared with the experimental data and quantum mechanical calculations. We found that both classical treatments describe the inner-shell ionization processes by positron impact reasonably well.

Mukoyama, Takeshi; T?kési, Károly; Nagashima, Yasuyuki

2014-11-01

377

Neutron-induced Cross Section Measurements of Calcium  

NASA Astrophysics Data System (ADS)

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 measured data will be used for a new calcium evaluation, which will be submitted with covariances to the ENDF/B nuclear data library.

Guber, K.; Kopecky, S.; Schillebeeckx, P.; Kauwenberghs, K.; Siegler, P.

2014-05-01

378

Neutron Cross-Section Measurements on Structural Materials at ORELA  

SciTech Connect

Neutron capture experiments, using isotopically enriched and natural samples of chromium and titanium, were performed on flight paths 6 and 7 at the 40 m flight station of ORELA. The experimental data were acquired using a pair of deuterated benzene detectors employing the now well-established pulse-height-weighting technique. These data were complemented by new total cross-section measurements where no useful previous data were available.

Guber, Klaus H [ORNL] [ORNL; Koehler, Paul [ORNL] [ORNL; Wiarda, Dorothea [ORNL] [ORNL; Harvey, John A [ORNL] [ORNL

2011-01-01

379

Trade, efficiency, and growth in a cross section of countries  

Microsoft Academic Search

Trade, Efficiency and Growth in a Cross Section of Countries. —Some cross-country studies of the determinants of growth suggest\\u000a only a modest role for trade policy. This study, measuring trade openness by the rate of growth of the share of exports in\\u000a GDP, argues that once the possibility of outliers for trade share growth is considered, a close relationship between

Edmund J. Sheehey

1995-01-01

380

Differential collision cross-sections for atomic oxygen  

NASA Technical Reports Server (NTRS)

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.

Torr, Douglas G.

1991-01-01

381

Top Quark Production Cross Section at the Tevatron  

SciTech Connect

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}.

Shabalina, E.; /Chicago U.

2006-05-01

382

Inclusive jet cross-section measurement at CDF  

SciTech Connect

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.

Norniella, Olga; /Barcelona, IFAE

2007-05-01

383

Radial Eigenmodes for a Toroidal Waveguide with Rectangular Cross Section  

SciTech Connect

In applying mode expansion to solve the CSR impedance for a section of toroidal vacuum chamber with rectangular cross section, we identify the eigenvalue problem for the radial eigenmodes which is different from that for cylindrical structures. In this paper, we present the general expressions of the radial eigenmodes, and discuss the properties of the eigenvalues on the basis of the Sturm-Liouville theory.

Rui Li

2012-07-01

384

Dielectronic-Recombination Cross-Sections of Hydrogenlike Argon  

E-print Network

PHYSICAL REVIEW A VOLUME 44, NUMBER 11 1 DECEMBER 1991 Dielectronic-recombination cross sections of hytlrogenlike argon D. R. DeWitt, D. Schneider, M. W. Clark, and M. H. Chen Latvrenee Livermore National Laboratory, University of California.... These trapped ions then undergo further ionization and other electron-ion 7185 1991 The American Physical Society DeWITT, SCHNEIDER, CLARK, CHEN, AND CHURCH interactions. In order to study dielectronic recombination in highly charged ions, the drift tubes...

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

1991-01-01

385

Experimental Electron-Impact K-Shell Ionization Cross Sections  

Microsoft Academic Search

Experimental electron-impact K-shell ionization cross sections obtained from a search of the literature up to December 1999 are tabulated according to atomic number and incident electron energy. The data taken from the original papers have been reevaluated, where necessary, using the K-shell fluorescence yields compiled by Hubbell et al. and by Bambynek. Data are presented for elements H through U.

Mantian Liu; Zhu An; Changhuan Tang; Zhengming Luo; Xiufeng Peng; Xianguan Long

2000-01-01

386

Negative ion detachment cross sections. Interim progress report  

SciTech Connect

The authors have measured absolute cross sections for electron detachment and charge exchange for collision of O and S with atomic hydrogen, have investigated the sputtering and photodesorption of negative ions from gas covered surfaces, and have begun an investigation of photon-induced field emission of electrons from exotic structures. Brief descriptions of these activities as well as future plans for these projects are given below.

Champion, R.L.; Doverspike, L.D.

1992-10-01

387

Neutron-Induced Cross Sections Measurements of Calcium  

SciTech Connect

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.

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

388

Top quark pair production cross section at the Tevatron  

SciTech Connect

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.

Cortiana, Giorgio; /INFN, Padua /Padua U.

2008-04-01

389

Total electron scattering cross sections. I - He, Ne, Ar, Xe  

NASA Technical Reports Server (NTRS)

The apparatus and experimental procedures used to obtain total electron scattering cross sections are described, and results are presented for He, Ne, Ar and Xe in the 4-300 eV incident energy range, together with statistical errors. The results are generally found to be in good agreement with previous data except at low impact energies. Serious discrepancies remain in Xe below 20 eV impact energy.

Nickel, J. C.; Imre, K.; Register, D. F.; Trajmar, S.

1985-01-01

390

Ionization Cross Section Measurement for Molecules in Mercury's Exosphere  

NASA Astrophysics Data System (ADS)

Electron impact ionization is widely used for neutral mass spectrometry; its energy and species dependent efficiency must be empirically characterized for instrument calibration. Ionization cross sections for a variety of elements and molecules have been measured, notably for simple molecules, atmospheric compounds, and hydrocarbons. Past investigations have usually focused on species that are gaseous in standard laboratory conditions which are easiest to handle and most commonly encountered by ground-based mass spectrometers. Space-based applications (e.g. studying planetary atmospheres or cometary outgassing) involve a much wider variety of species, including refractory molecules in gas phase, that have never been measured. A new facility has been built to determine the cross sections of these species using an evaporative source to generate a molecular beam of refractory compounds. In addition to the absolute cross sections for ion production of the original species, this experiment also examines the fragmentation products and their dissociation energies. Ionization energies are probed from threshold to 1 keV. We are specifically interested in molecules that may contribute to the exosphere of Mercury that could explain the anomalous hot distributions of magnesium and calcium that have been seen by Messenger. By targeting possible progenitor molecules of the observed atomic species (i.e. CaO, MgO, and other oxides/hydroxides) we aim to prepare for the next mission to Mercury by BepiColombo. Preliminary results will be presented for these new compounds as well as baseline cross sections of well-studied species for validation.

Miles, P.; Livi, S. A.; Patrick, E.; Ogasawara, K.

2012-12-01

391

Top-Quark Cross Section and Properties at the Tevatron  

SciTech Connect

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.

Wagner, Wolfgang; /Wuppertal U.

2009-09-01

392

Humeral cross-sectional shape in suspensory primates and sloths.  

PubMed

Studies on the cross-sectional geometry of long bones in African apes have documented that shape ratios derived from second moments of area about principle axes (e.g., Imax /Imin ) are often correlated with habitual locomotor behaviors. For example, humeral cross-sections tend to appear more circular in more arboreal and forelimb suspensory chimpanzees compared with terrestrial quadrupedal gorillas. These data support the hypothesis that cross-sections that are more circular in shape are adapted for multidirectional loading regimes and bending moments encountered when using acrobatic locomotor behaviors. Whether a more circular humerus reflects greater use of forelimb suspension in other primates and nonprimate mammals is unknown. In this study, cross-sections at or near midshaft of the humerus were obtained from anthropoid primates that differ in their use of forelimb suspension, as well as from two genera of suspensory sloths. Imax /Imin ratios were compared within and between groups, and correlations were made with behavioral data. In broad comparisons, observed differences in morphology follow predicted patterns. Humeri of suspensory sloths are circular. Humeri of the more suspensory hominoids tend to be more circular than those of quadrupedal taxa. Humeri of the suspensory atelines are similar to hominoids, while those of Cebus are more like nonsuspensory cercopithecoids. There is, however, considerable overlap between taxa and within finer comparisons variation between species are not in the predicted direction. Thus, although Imax /Imin ratios of the humerus are informative for characterizing generalized locomotor modes (i.e., forelimb suspensory vs. quadrupedal), additional structural information is needed for more fine-grained assessments of locomotion. PMID:23408647

Patel, Biren A; Ruff, Christopher B; Simons, Erin L R; Organ, Jason M

2013-04-01

393

Induced-emission cross sections in neodymium laser glasses  

Microsoft Academic Search

A method for calculating induced-emission cross sections in neodymium laser glasses, based on simple absorbance measurements, has been demonstrated. Absorption and emission transition probabilities of four silicate-base neodymium laser glasses have been characterized in terms of the Judd-Ofelt (JO) model of crystal-field-induced electric-dipole transitions. Absolute absorption intensities in 3669A, ED-2, LSG-91H, and S33 glasses were measured and used to determine

WILLIAM F. KRUPKE

1974-01-01

394

Relativistic Elastic Differential Cross Sections for Equal Mass Nuclei  

E-print Network

The effects of relativistic kinematics are studied for nuclear collisions of equal mass nuclei. It is found that the relativistic and non-relativistic elastic scattering amplitudes are nearly indistinguishable, and, hence, the relativistic and non-relativistic differential cross sections become indistinguishable. These results are explained by analyzing the Lippmann-Schwinger equation with the first order optical potential that was employed in the calculation

C. M. Werneth; K. M. Maung; W. P. Ford

2014-11-18

395

Vessel Cross-Sectional Diameter Measurement on Color Retinal Image  

Microsoft Academic Search

Vessel cross-sectional diameter is an important feature for analyzing retinal vascular changes. In automated retinal image\\u000a analysis, the measurement of vascular width is a complex process as most of the vessels are few pixels wide or suffering from\\u000a lack of contrast. In this paper, we propose a new method to measure the retinal blood vessel diameter which can be used

Alauddin Bhuiyan; Baikunth Nath; Joselíto J. Chua; Ramamohanarao Kotagiri

2008-01-01

396

Absolute cross sections for elastic electron scattering from methylformamide  

NASA Astrophysics Data System (ADS)

Elastic electron scattering from gaseous methylformamide (N-methylformamide, C2H5NO) has been investigated. Absolute elastic differential cross sections (DCSs) were determined both experimentally and theoretically for the incident energies from 50 to 300 eV. The measurements were performed using a cross-beam technique, for scattering angles from 20° to 110°. Relative elastic DCSs were measured as a function of both the angle and the incident energy and the absolute DCSs were determined using the relative flow method. The calculations of electron interaction cross sections are based on a corrected form of the independent-atom method, known as the SCAR (screen corrected additivity rule) procedure and using an improved quasifree absorption model. Calculated integral cross sections have been presented, as well, both for methylformamide and formamide, in the energy range 10-1000 eV, and discussed. The results are compared with and discussed regarding existing data for other small molecules representing building blocks of large biomolecules.

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

2012-04-01

397

Cross section of $^{36}$S(n,$\\gamma$)$^{37}$S  

E-print Network

At the Karlsruhe pulsed 3.75\\,MV Van de Graaff accelerator the ^{36}S(n,\\gamma)^{37}S(5.05\\,min) cross section was measured by the fast cyclic activation technique via the 3.103\\,MeV \\gamma--ray line of the ^{37}S--decay. Samples of elemental sulfur enriched in ^{36}S by 5.933\\,\\% were irradiated between two gold foils which served as capture standards. The capture cross section was measured at the neutron energies 25, 151, 176, and 218\\,keV, respectively. The ^{36}S(n,\\gamma)^{37}S--cross section in the thermonuclear and thermal energy range has been calculated using the direct--capture (DC) model combined with the folding procedure used for the determination of the potentials. The non--resonant experimental data for this reaction can be reproduced excellently using this method. The input parameters of the DC--calculation (masses, Q--values, nuclear density distributions, spectroscopic factors, spin--parity assignments and excitation energies of the low--lying states of the residual nucleus) have been taken ...

Beer, H; Popov, Yu P; Balogh, W; Herndl, H; Oberhummer, Heinz

1995-01-01

398

Three Dimensional Cross-Sectional Properties From Bone Densitometry  

NASA Technical Reports Server (NTRS)

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.

Cleek, Tammy M.; Whalen, Robert T.; Dalton, Bonnie P. (Technical Monitor)

2001-01-01

399

Hydraulic geometry of river cross sections; theory of minimum variance  

USGS Publications Warehouse

This study deals with the rates at which mean velocity, mean depth, and water-surface width increase with water discharge at a cross section on an alluvial stream. Such relations often follow power laws, the exponents in which are called hydraulic exponents. The Langbein (1964) minimum-variance theory is examined in regard to its validity and its ability to predict observed hydraulic exponents. The variables used with the theory were velocity, depth, width, bed shear stress, friction factor, slope (energy gradient), and stream power. Slope is often constant, in which case only velocity, depth, width, shear and friction factor need be considered. The theory was tested against a wide range of field data from various geographic areas of the United States. The original theory was intended to produce only the average hydraulic exponents for a group of cross sections in a similar type of geologic or hydraulic environment. The theory does predict these average exponents with a reasonable degree of accuracy. An attempt to forecast the exponents at any selected cross section was moderately successful. Empirical equations are more accurate than the minimum variance, Gauckler-Manning, or Chezy methods. Predictions of the exponent of width are most reliable, the exponent of depth fair, and the exponent of mean velocity poor. (Woodard-USGS)

Williams, Garnett P.

1978-01-01

400

Optical excitation cross section of erbium in GaN.  

PubMed

Epilayers of erbium-doped GaN (GaN:Er) were synthesized by metal-organic chemical vapor deposition, and the optical excitation cross section (?(exc)) of Er ions in this host material were determined. Photoluminescence (PL) measurements were made using laser diodes at excitation wavelengths of 375 and 405 nm, and the integrated emission intensity at 1.54 ?m was measured as a function of excitation photon flux. Together with time-resolved PL measurements, values of ?(exc) of Er ions in GaN:Er were obtained. For excitation at 375 nm, the observed excitation cross section was found to be 4.6×10(-17) cm(-2), which is approximately three orders of magnitude larger than that using resonant excitation. Based on the present and previous works, the optical excitation cross section ?(exc) of Er ions in GaN:Er as a function the excitation wavelength has been obtained. The large values of ?(exc) with near-band-edge excitation makes GaN:Er attractive for realization of chip-scale photonic devices for optical communications. PMID:23434981

Feng, I-Wen; Li, Jing; Lin, Jingyu; Jiang, Hongxing; Zavada, John

2013-02-20

401

Extension of the Bgl Broad Group Cross Section Library  

NASA Astrophysics Data System (ADS)

The broad group cross-section libraries BUGLE and BGL are applied for reactor shielding calculation using the DOORS package based on discrete ordinates method and multigroup approximation of the neutron cross-sections. BUGLE and BGL libraries are problem oriented for PWR or VVER type of reactors respectively. They had been generated by collapsing the problem independent fine group library VITAMIN-B6 applying PWR and VVER one-dimensional radial model of the reactor middle plane using the SCALE software package. The surveillance assemblies (SA) of VVER-1000/320 are located on the baffle above the reactor core upper edge in a region where geometry and materials differ from those of the middle plane and the neutron field gradient is very high which would result in a different neutron spectrum. That is why the application of the fore-mentioned libraries for the neutron fluence calculation in the region of SA could lead to an additional inaccuracy. This was the main reason to study the necessity for an extension of the BGL library with cross-sections appropriate for the SA region. Comparative analysis of the neutron spectra of the SA region calculated by the VITAMIN-B6 and BGL libraries using the two-dimensional code DORT have been done with purpose to evaluate the BGL applicability for SA calculation.

Kirilova, Desislava; Belousov, Sergey; Ilieva, Krassimira

2009-08-01

402

Differential cross section ratios for p + He collisions  

NASA Astrophysics Data System (ADS)

We have measured differential cross sections for single capture, double capture, and transfer excitation in p + He collisions. In the double to single capture cross section ratios RDC we observe peak structures around 0.5 to 1.0 mrad similar to those reported previously for the double to single ionization and transfer-ionization to single capture ratios RDI and RTI, respectively. However, surprisingly in our data for RDC the relative importance of these peaks maximize at a relatively small projectile energy of about 50 to 75 keV while in RDI and RTI the structures become increasingly pronounced with increasing projectile energy and are not observed below approximately 200 keV. We also found a pronounced peak structure in the double ratio R =RTE/RDE, where RTE is the transfer excitation to single capture ratio and RDE the double to single excitation ratio^1. Our theoretical calculation qualitatively reproduces the peak structure in R if the elastic scattering between the projectile and the residual target ion is treated quantum-mechanically. Finally, we revisited doubly differential single ionization data reported earlier^2 and found peak structures in the ratios between cross sections for different electron energies. ^1W. Htwe et al., PRL 73, 1348 (1994) ^2 T. Vajnai et al., PRL 74, 3588 (1995)

Schulz, Michael; Hasan, Ahmad; Vajnai, Tibor; Zapukhlyak, Miroslav; Kirchner, Tom

2007-06-01

403

Summary of the Workshop on Neutron Cross Section Covariances  

SciTech Connect

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.

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

404

\\ttbar and single top cross sections at the Tevatron  

SciTech Connect

We present a summary of the latest measurements of the top pair and single top cross sections performed by the CDF and D0 collaborations at the Fermilab Tevatron collider. The Fermilab Tevatron collider ended its run on September 30, 2011 after delivering more than 10 fb{sup -1} of p{bar p} collision data per experiment at {radical}s = 1.96 TeV. A large sample of top quarks collected by the CDF and D0 experiments allows to perform precision measurements of their production which is predicted to occur within the standard model (SM) either in pairs via strong interactions or as single top events via electroweak interactions. Such measurements represent an important test of the theoretical calculations which predict the t{bar t} and single top production cross sections with a precision of 6% to 8% and 5%, respectively. Precise measurements of top pair cross section ({sigma}{sub t{bar t}}) in different t{bar t} final states and single top production via different production mechanisms are highly desirable as they are sensitive to the non-SM particles that may appear in top quark production or decays.

CDF, Elizaveta Shabalina for; collaborations, D0

2012-01-01

405

State-selective radiative recombination cross sections of argon ions  

NASA Astrophysics Data System (ADS)

The n-, (n,l)- and fine-structure level state-selective radiative recombinations (RR) cross sections of argon ions Ar18+,Ar13+,Ar7+ and Ar+ are obtained with the semi-classical Kramer formula, the relativistic self-consistent field (RSCF) method and the relativistic configuration interaction (RCI) method. It is found that for the highly charged ions with few electrons, the cross sections calculated with these three methods are in good agreement with each other. But as the number of electrons increases, the Kramer formula deviates from the RSCF and RCI results. For instance, when the energy of the incident electron is larger than 100 eV, the n-state selective cross sections of Ar7+ calculated from the Kramer formula are underestimated for more than 50%. The RSCF results are in general agreement with the RCI results. However, for the low charged ions, a clear distinction appears due to the strong configuration interaction, especially near the Cooper minimum. The n-resolved (n?10) and total Maxwellian averaged rate coefficients are calculated, and the analytic fitting parameters are also provided.

Li, C. Y.; Qu, Y. Z.; Wang, J. G.

2012-10-01

406

German Radar Observation Shuttle Experiment (ROSE)  

NASA Technical Reports Server (NTRS)

The success of radar sensors in several different application areas of interest depends on the knowledge of the backscatter of radar waves from the targets of interest, the variance of these interaction mechanisms with respect to changing measurement parameters, and the determination of the influence of he measuring systems on the results. The incidence-angle dependency of the radar cross section of different natural targets is derived. Problems involved by the combination of data gained with different sensors, e.g., MSS-, TM-, SPOTand SAR-images are analyzed. Radar cross-section values gained with ground-based radar spectrometers and spaceborne radar imaging, and non-imaging scatterometers and spaceborne radar images from the same areal target are correlated. The penetration of L-band radar waves into vegetated and nonvegetated surfaces is analyzed.

Sleber, A. J.; Hartl, P.; Haydn, R.; Hildebrandt, G.; Konecny, G.; Muehlfeld, R.

1984-01-01

407

A wave tank study of the dependence of X band cross sections on wind speed and water temperature  

NASA Technical Reports Server (NTRS)

The effects of varying the water temperature, wind speed, and wind stress on the values of backscatter were investigated using measurements of normalized radar cross sections of wind-generated waves, made at X band for both vertical and horizontal polarization for incidence angles 10, 28, 48, and 68 deg. The experiment was conducted using the Naval Research Laboratory wind-wave tank. Measurements made for a wide range of wind speeds and water temperatures are compared with results of backscattering models currently in use.

Keller, Mary Ruth; Keller, William C.; Plant, William J.

1992-01-01

408

Propionaldehyde infrared cross-sections and band strengths  

NASA Astrophysics Data System (ADS)

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.

Köro?lu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.

2015-02-01

409

Neutron displacement damage cross sections for SiC  

NASA Astrophysics Data System (ADS)

Calculations of neutron displacement damage cross sections for SiC are presented. We use Biersack and Haggmark's empirical formula in constructing the electronic stopping power, which combines Lindhard's model at low PKA energies and Bethe-Bloch's model at high PKA energies. The electronic stopping power for polyatomic materials is computed on the basis of Bragg's Additivity Rule. A continuous form of the inverse power law potential is used for nuclear scattering. Coupled intergro-differential equations for the number of displaced atoms j, caused by PKA i, are then derived. The procedure outlined above gives partial displacement cross sections, displacement cross sections for each specie of the lattice, and for each PKA type. The corresponding damage rates for several fusion and fission neutron spectra are calculated. The stoichiometry of the irradiated material is investigated by finding the ratio of displacements among various atomic species. The role of each specie in displacing atoms is also investigated by calculating the fraction of displacements caused by each PKA type. The study shows that neutron displacement damage rates of SiC in typical magnetic fusion reactor first walls will be ~ 10-15 dpa MW -1 m 2; in typical lead-protected inertial confinement fusion reactor first walls they will be ~ 15-20 dpa MW -1 m 2. For fission spectra, we find that the neutron displacement damage rate of SiC is ~ 74 dpa per 10 27 n/m 2 in FFTF, ~ 39 dpa per 10 27 n/m 2 in HFIR, and 25 dpa per 10 27 n/m 2 in NRU. Approximately 80% of displacement atoms are shown to be of the carbon-type.

Hanchen, Huang; Ghoniem, Nasr

1993-02-01

410

Neutron Cross Section Covariances for Structural Materials and Fission Products  

SciTech Connect

We describe neutron cross section covariances for 78 structural materials and fission products produced for the new US evaluated nuclear reaction library ENDF/B-VII.1. Neutron incident energies cover full range from 10{sup -5} eV to 20 MeV and covariances are primarily provided for capture, elastic and inelastic scattering as well as (n,2n). The list of materials follows priorities defined by the Advanced Fuel Cycle Initiative, the major application being data adjustment for advanced fast reactor systems. Thus, in addition to 28 structural materials and 49 fission products, the list includes also {sup 23}Na which is important fast reactor coolant. Due to extensive amount of materials, we adopted a variety of methodologies depending on the priority of a specific material. In the resolved resonance region we primarily used resonance parameter uncertainties given in Atlas of Neutron Resonances and either applied the kernel approximation to propagate these uncertainties into cross section uncertainties or resorted to simplified estimates based on integral quantities. For several priority materials we adopted MF32 covariances produced by SAMMY at ORNL, modified by us by adding MF33 covariances to account for systematic uncertainties. In the fast neutron region we resorted to three methods. The most sophisticated was EMPIRE-KALMAN method which combines experimental data from EXFOR library with nuclear reaction modeling and least-squares fitting. The two other methods used simplified estimates, either based on the propagation of nuclear reaction model parameter uncertainties or on a dispersion analysis of central cross section values in recent evaluated data files. All covariances were subject to quality assurance procedures adopted recently by CSEWG. In addition, tools were developed to allow inspection of processed covariances and computed integral quantities, and for comparing these values to data from the Atlas and the astrophysics database KADoNiS.

Hoblit, S.; Hoblit,S.; Cho,Y.-S.; Herman,M.; Mattoon,C.M.; Mughabghab,S.F.; Oblozinsky,P.; Pigni,M.T.; Sonzogni,A.A.

2011-12-01

411

Hadronic Production of psi(2S) Cross section and Polarization  

SciTech Connect

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.

Chung, Kwangzoo; /Carnegie Mellon U.

2008-05-01

412

Helium-adsorbate cross section on highly corrugated substrates  

SciTech Connect

The interaction of He atoms with adsorbates placed on strongly corrugated substrates is investigated both theoretically and experimentally. An analysis of the scattering process within the transition matrix approach suggests that the normalized differential cross section, associated with the attenuation of coherent diffraction due to incoherent scattering in the presence of adsorbates, is expected to be largest for the most intense coherent diffraction peaks. For the adsorption of K on Cu(115), this trend is experimentally observed. {copyright} {ital 1996 The American Physical Society.}

Armand, G.; Schwenger, L.; Ernst, H. [Commisariat a lEnergie Atomique Saclay, Departement de Recherche sur lEtat Condense, les Atomes et les Molecules/Service de Recherche sur les Surfaces et lIrradiation de la Matiere, 91191 Gif Sur Yvette (France)] [Commisariat a lEnergie Atomique Saclay, Departement de Recherche sur lEtat Condense, les Atomes et les Molecules/Service de Recherche sur les Surfaces et lIrradiation de la Matiere, 91191 Gif Sur Yvette (France)

1996-02-01

413

An accelerator test of semi-empirical cross-sections  

NASA Technical Reports Server (NTRS)

Experimentally measured yields of isotopes of elements from Mg-12 to K-19 resulting from the fragmentation of Ar-40 are compared with calculated yields based on semiempirical cross-section formulae. The measurements, made at the LBL Bevalac using a beam of 287 MeV/amu Ar-40 incident on a CH2 target, achieve excellent mass resolution (up to 0.2 amu) through the use of a Si(Li) detector telescope. The general agreement between calculation and experiment is good (rms difference of about 24 percent), but some significant differences are reported.

Lau, K. H.; Mewaldt, R. A.; Wiedenbeck, M. E.

1983-01-01

414

Ab initio method for calculating total cross sections  

NASA Technical Reports Server (NTRS)

A method for calculating total cross sections without formally including nonelastic channels is presented. The idea is to use a one channel T-matrix variational principle with a complex correlation function. The derived T matrix is therefore not unitary. Elastic scattering is calculated from T-parallel-squared, but total scattering is derived from the imaginary part of T using the optical theorem. The method is applied to the spherically symmetric model of electron-hydrogen scattering. No spurious structure arises; results for sigma(el) and sigma(total) are in excellent agreement with calculations of Callaway and Oza (1984). The method has wide potential applicability.

Bhatia, A. K.; Schneider, B. I.; Temkin, A.

1993-01-01

415

Extranodal lymphoma in the thorax: cross-sectional imaging findings.  

PubMed

The purpose of this review is to discuss and illustrate the spectrum of appearances of extranodal lymphoma in the thorax, including the lungs, pleura, heart, thymus, chest wall, thoracic spine, and breast, using current cross-sectional imaging techniques, such as multidetector computed tomography, positron-emission tomography/computed tomography, magnetic resonance imaging, and sonography. Extranodal lymphoma can affect any organ or tissue in the thorax, and can be mistaken for other inflammatory or neoplastic conditions. This review should alert the radiologist to consider extranodal lymphoma in the appropriate clinical setting to ensure timely diagnosis, correct staging, and accurate post-treatment evaluation to optimize treatment regimens. PMID:19348852

Lee, W-K; Duddalwar, V A; Rouse, H C; Lau, E W F; Bekhit, E; Hennessy, O F

2009-05-01

416

Dielectronic Recombination Cross-Sections of Fluorinelike Xenon  

E-print Network

PHYSICAL REVIEW A VOLUME 47, NUMBER 3 MARCH 1993 Dielectronic recombination cross sections of Snorinelike xenon D. R. DeWitt, D. Schneider, M. H. Chen, and M. B. Schneider Laturence Li uermore National Laboratory, Uniuersity of California.... E. Marrs, M. A. Levine, C. L. Bennett, M. H. Chen, J. R. Henderson, M. B. Schneider, and J. H. Scofield, Phys. Rev. Lett. 62, 2104 (1989). [4] R. Ali, C. P. Bhalla, C. L. Cocke, M. Schulz, and M. Stockli, Phys. Rev. A 44, 223 (1991);R. Ali, C. P...

Dewitt, D. R.; Schneider, D.; Chen, M. H.; Schneider, M. B.; Church, David A.; Weinberg, G.; Sakurai, M.

1993-01-01

417

Fission cross section calculations of actinides with EMPIRE code  

SciTech Connect

The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.

Sin, M.; Oblozinsky, P.; Herman,M.; Capote,R.

2010-04-30

418

Reaction Cross Section in Heavy-Ion Collisions  

SciTech Connect

Previously a compact formula for total reaction cross section for heavy-ion collisions as a function of energy was obtained by treating the angular momentum $l$ as a continuous variable. The accuracy of the continuum approximation is assessed and corrections are evaluated. The accuracy of the compact equation can be improved by a simple modification, if a higher accuracy is required. Simple rules to determine the barrier height and the penetration probability for the $l$ partial wave from experimental data are presented, for the collision of identical or non-identical nuclei.

Wong, Cheuk-Yin [ORNL

2012-01-01

419

SCAMPI: A code package for cross-section processing  

SciTech Connect

The SCAMPI code package consists of a set of SCALE and AMPX modules that have been assembled to facilitate user needs for preparation of problem-specific, multigroup cross-section libraries. The function of each module contained in the SCANTI code package is discussed, along with illustrations of their use in practical analyses. Ideas are presented for future work that can enable one-step processing from a fine-group, problem-independent library to a broad-group, problem-specific library ready for a shielding analysis.

Parks, C.V.; Petrie, L.M.; Bowman, S.M.; Broadhead, B.L.; Greene, N.M.; White, J.E.

1996-04-01

420

Thermal neutron cross section of liquid and solid mesitylene  

NASA Astrophysics Data System (ADS)

Total cross sections of mesitylene at 293 K and at 89 K were measured at the electron LINAC based pulsed neutron source of Centro Atómico Bariloche. Preliminary frequency spectra were proposed for liquid and solid mesitylene at those temperatures combining experimental and synthetic contributions. Scattering law data files were generated with the NJOY nuclear data processing system. Good agreement between experiments and calculations is found, which represents a primary validation of the scattering kernels which are now being used for the design and optimization of a cold moderator employing that material.

Cantargi, F.; Blostein, J. J.; Torres, L.; Granada, J. R.

2006-08-01

421

Final Report - Nucelar Astrophysics & Neutron Cross Section Measurements  

SciTech Connect

This enduring research program of 28 years has taken advantage of the excellent research facility of ORELA at Oak Ridge National Laboratory. The fruitful collaborations include a number of scientists from ORNL and some from LASL. This program which has ranged from nuclear structure determinations to astrophysical applications has resulted in the identification and/or the refinement of the nuclear properties of more than 5,000 nuclear energy levels or compound energy states. The nuclei range from 30Si to 250Cf, the probes range from thermal to 50 MeV neutrons, and the studies range from capture gamma ray spectra to total and differential scattering and absorption cross sections. Specific target nuclei studied include the following: 120Sn 124Sn 125Sn 113Sn 115Sn 117Sn 119Sn 249Cf 33S 34S 249Bk 186Os 187Os 188Os 30Si 32S 40Ca 48Ca 60Ni 54Fe 86Kr 88Sr 40Ar 122Sn 90Zr 122Sn(n,?) 208Pb 204Pb 52Cr 54Cr 50Cr 53Cr As can be seen, we have studied, on average, more than one isotope per year of grant funding and have focused on exploiting those elements having multiple isotopes in order to investigate systematic trends in nuclear properties, for the purpose of providing more stringent tests of the nuclear spherical optical model with a surface imaginary potential. We have investigated an l-dependence of the real-well depth of the spherical optical model; we have used these measurements to deduce the existence of doorway states in the compound nucleus; and in the total cross section measurements we have, in addition to resonance energies and widths, obtained values for the level density and neutron strength function. Due to the high neutron energy resolution of the ORELA and in some cases the addition of differential scattering cross section data, we have been able to disaggregate the spin states and provide level spacing and strength function for each partial wave in the neutron-nucleus interaction, in some cases up to d5/2. In the following we will summarize the most recent analyses of neutron total cross section measurements, some of which have not been previously reported.

Carlton, Robert F

2009-12-01

422

Decay widths and total cross sections in perturbative QCD  

NASA Astrophysics Data System (ADS)

The current status of analytic higher-order perturbative computations of total cross sections and decay widths in Quantum Chromodynamics is reviewed. Important issues are the methodology of renormalization-group evaluations, the ambiguities of the renormalization scheme and its scale, and the technical challenge of calculating many-loop diagrams. As examples, the authors consider the quantities ?tot(e+e--->hadrons) and ?(?--->??+hadrons) up to O(?3s) as well as ?(H-->hadrons) up to O(?2s). The evaluation of the four-loop QED beta function is also described. The problem of theoretical uncertainty estimates in perturbative calculations is briefly discussed.

Surguladze, Levan R.; Samuel, Mark A.

1996-01-01

423

Photoneutron cross sections for unstable neutron-rich oxygen isotopes.  

PubMed

The dipole response of stable and unstable neutron-rich oxygen nuclei of masses A = 17 to A = 22 has been investigated experimentally utilizing electromagnetic excitation in heavy-ion collisions at beam energies about 600 MeV/nucleon. A kinematically complete measurement of the neutron decay channel in inelastic scattering of the secondary beam projectiles from a Pb target was performed. Differential electromagnetic excitation cross sections d sigma/dE were derived up to 30 MeV excitation energy. In contrast to stable nuclei, the deduced dipole strength distribution appears to be strongly fragmented and systematically exhibits a considerable fraction of low-lying strength. PMID:11415271

Leistenschneider, A; Aumann, T; Boretzky, K; Cortina, D; Cub, J; Datta Pramanik, U; Dostal, W; Elze, T W; Emling, H; Geissel, H; Grünschloss, A; Hellstr, M; Holzmann, R; Ilievski, S; Iwasa, N; Kaspar, M; Kleinböhl, A; Kratz, J V; Kulessa, R; Leifels, Y; Lubkiewicz, E; Münzenberg, G; Reiter, P; Rejmund, M; Scheidenberger, C; Schlegel, C; Simon, H; Stroth, J; Sümmerer, K; Wajda, E; Walús, W; Wan, S

2001-06-11

424

Differential cross sections for positron scattering from alkali atoms  

SciTech Connect

Close-coupling calculations for differential cross sections for elastic and inelastic positron-alkali scattering at incident energies between 1 eV and 100 eV will be presented. Particular emphasis is placed on excitation of the resonant (ns){sup 2}S {yields} (np){sup 2}P{sup o} and the optically forbidden (ns){sup 2}S {yields} (n{prime}d){sup 2}D transitions. The results will be compared with first order DWBA calculations to assess the importance of channel coupling in the theoretical description of these collision processes.

DeVries, K.M.; Bartschat, K.; McEachran, R.P. [and others

1993-05-01

425

Cross sections and reaction rates of relevance to aeronomy  

SciTech Connect

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.

Fox, J.L. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

426

Charge exchange and ionization cross sections of H{sup +}+H collision in dense quantum plasmas  

SciTech Connect

The plasma screening effects of dense quantum plasmas on H{sup +}+H charge exchange and ionization cross sections are calculated by the classical trajectory Monte Carlo method. For charge exchange cross sections, it is found that the screening effects reduce cross sections slightly in weak screening conditions. However, cross sections are reduced substantially in strong screening conditions. For ionization cross sections, with the increase of screening effects, cross sections for low energies increase more rapidly than those for high energies. When the screening effects are strong enough, it is found that ionization cross sections decrease with the increase of incident H{sup +} energy. In addition, the cross sections have been compared with those in weakly coupled plasmas. It is found that in weak screening conditions, plasma screening effects in the two plasmas are approximately the same, while in strong screening conditions, screening effects of dense quantum plasmas are stronger than those of weakly coupled plasmas.

Zhang, Ling-yu; Qi, Xin; Zhao, Xiao-ying; Meng, Dong-yuan; Xiao, Guo-qing [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China); Duan, Wen-shan [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, Gansu 730070 (China)] [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, Gansu 730070 (China); Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China) [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China and University of Chinese Academy of Sciences, Beijing 100049 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2013-11-15

427

Resolution function of nonsinusoidal radar signals. I. Range-velocity resolution with rectangular pulses  

Microsoft Academic Search

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

N. J. Mohamed

1990-01-01

428

Resolution function of nonsinusoidal radar signals. I - Range-velocity resolution with rectangular pulses  

Microsoft Academic Search

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

Nasser J. Mohamed

1990-01-01

429

[Spinal trauma: first aid from cross-sectional imaging].  

PubMed

The diagnosis of the traumatized spine is one of the key issues for trauma radiologists. The cross-sectional imaging procedures, computed tomography (CT) and magnetic resonance imaging (MRI) are the essential methods in spinal trauma radiology. These modalities are of great help in accurately assessing injury patterns and extent and in providing indications of patient outcome. In contrast to cross-sectional imaging, radiography has a role in the evaluation of minor spinal trauma only. It is generally accepted that trauma radiologists do not use typical classifications to evaluate the spine partly because such an ideal classification system does not yet exist. Not least because of this classification difficulty, eponyms and synonyms are widely used to describe traumatology of the spine as a high level of specific information is included in these various terms. The members of the trauma team should be aware of the strengths and limitations of the methods used in the assessment of the spine. This article provides a brief outline of fundamental knowledge about the diagnosis of spinal trauma. PMID:25216569

Schueller, G; Schueller-Weidekamm, C

2014-09-01

430

Electron-hydrogen cross section computation for astrophysical applications  

NASA Astrophysics Data System (ADS)

Our contribution focuses on the electron-hydrogen scattering and is intended as an extension of available atomic databases (e.g [1]) used by the astronomers and stellar/solar physicists. These databases often lack required precision and sometimes even major resonances, which are essential for correct transition rates extraction and thus for the description of astrophysical phenomena. Our aim is to obtain a controlled approximation of scattering cross section energy dependence for all relevant energies and (de)excitational transitions. The poster summarises results computed by freely available (e.g. [2], [3]) computer codes and compares them with our original results. Low energy cross sections - up to this time a domain of R-matrix packages - have been recomputed using exterior complex scaling implemented in B-splines (see [4]), whereas higher energies using different types of Born approximation.[4pt] [1] The Aladdin database at http://www-amdis.iaea.org/ALADDIN/[0pt] [2] UK RmaX at http://amdpp.phys.strath.ac.uk/UK$RmaX/[0pt] [3] Scott et al., Comp. Phys. Comm. 180 (2009) 2424-2449.[0pt] [4] McCurdy, Rescigno, J. Phys. B: At. Mol. Opt. Phys. 37 (2004) 917-936.

Benda, Jakub; Houfek, Karel

2012-06-01

431

Difference cross sections of unpolarized SIDIS with transverse momentum dependence  

NASA Astrophysics Data System (ADS)

Previously we showed that, based only on charge conjugation and isospin invariance of strong interactions, the difference cross sections of hadrons with opposite charge in semi-inclusive deep inelastic scattering (SIDIS) e+N?l+h+X are expressed solely in terms of the valence-quark densities and certain nonsinglet combinations of fragmentation functions (FFs). This allowed us to determine these quantities in a model-independent way. Now we extend this approach to processes when the transverse momentum of the final hadron is measured as well. We show that the difference cross sections of unpolarized SIDIS on proton and deuterium targets, d?Nh+-h-, d?N?+-?- and d?NK+-K-, are expressed solely in terms of the transverse momentum-dependent (TMD) unpolarized valence-quark densities and FFs, and the valence-quark Boer-Mulders and Collins functions. This allows us to determine them separately and study the flavor dependence of the quark transverse momentum. Measurements on the deuterium target, d?dh+-h-, d?d?+-?- and d?dK+-K-, provide three independent measurements for the sum of the TMD valence-quark densities and Boer-Mulders functions: (u1,V+d1,V) and (h1,uV?+h1,dV?).

Christova, Ekaterina

2014-09-01

432

Neutron cross section standards and instrumentation. Annual report  

SciTech Connect

The objective of this interagency program is to provide accurate neutron interaction measurements for the US Department of Energy nuclear programs which include waste disposal, fusion, safeguards, defense, fission, and personnel protection. These measurements are also useful to other energy programs which indirectly use the unique properties of the neutron for diagnostic and analytical purposes. The work includes the measurement of reference cross sections and related neutron data employing unique facilities and capabilities at NIST and other laboratories as required; leadership and participation in international intercomparisons and collaborations; the preservation of standard reference deposits and the development of improved neutron detectors and measurement methods. A related and essential element of the program is critical evaluation of neutron interaction data including international coordinations. Data testing of critical data for important applications is included. The program is jointly supported by the Department of Energy and the National Institute of Standards and Technology. This report from the National Institute of Standards and Technology contains a summary of the accomplishments of the Neutron Cross Section Standards and Instrumentation Project during the third year of this three-year interagency agreement. The proposed program and required budget for the following three years are also presented. The program continues the shifts in priority instituted in order to broaden the program base.

Wasson, O.A.

1993-07-01

433

CROSS SECTION EVALUATIONS FOR ENDF/B-VII.  

SciTech Connect

This is the final report of the work performed under the LANL contract on neutron cross section evaluations for ENDF/B-VII (April 2005-May 2006). The purpose of the contract was to ensure seamless integration of the LANL neutron cross section evaluations in the new ENDF/B-VII library. The following work was performed: (1) LANL evaluated data files submitted for inclusion in ENDF/B-VII were checked and, when necessary, formal formatting errors were corrected. As a consequence, ENDF checking codes, run on all LANL files, do not report any errors that would rise concern. (2) LANL dosimetry evaluations for {sup 191}Ir and {sup 193}Ir were completed to match ENDF requirements for the general purpose library suitable for transport calculations. A set of covariances for both isotopes is included in the ENDF files. (3) Library of fission products was assembled and successfully tested with ENDF checking codes, processed with NJOY-99.125 and simple MCNP calculations. (4) KALMAN code has been integrated with the EMPIRE system to allow estimation of covariances based on the combination of measurements and model calculations. Covariances were produced for 155,157-Gd and also for 6 remaining isotopes of Gd.

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

2006-06-05

434

Effect of strongly coupled plasma on photoionization cross section  

SciTech Connect

The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li{sup +2}, C{sup +5}, Al{sup +12}) and lithium like ions (C{sup +3}, O{sup +5}). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.

Das, Madhusmita, E-mail: msdas@barc.gov.in [Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, India and Theoretical Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India)] [Department of Physics, Indian Institute of Technology, Powai, Mumbai 400076, India and Theoretical Physics Division, Bhabha Atomic Research Center, Mumbai 400085 (India)

2014-01-15

435

Research on Fast-Doppler-Broadening of neutron cross sections  

SciTech Connect

A Fast-Doppler-Broadening method is developed in this work to broaden Continuous Energy neutron cross-sections for Monte Carlo calculations. Gauss integration algorithm and parallel computing are implemented in this method, which is unprecedented in the history of cross section processing. Compared to the traditional code (NJOY, SIGMA1, etc.), the new Fast-Doppler-Broadening method shows a remarkable speedup with keeping accuracy. The purpose of using Gauss integration is to avoid complex derivation of traditional broadening formula and heavy load of computing complementary error function that slows down the Doppler broadening process. The OpenMP environment is utilized in parallel computing which can take full advantage of modern multi-processor computers. Combination of the two can reduce processing time of main actinides (such as {sup 238}U, {sup 235}U) to an order of magnitude of 1{approx}2 seconds. This new method is fast enough to be applied to Online Doppler broadening. It can be combined or coupled with Monte Carlo transport code to solve temperature dependent problems and neutronics-thermal hydraulics coupled scheme which is a big challenge for the conventional NJOY-MCNP system. Examples are shown to determine the efficiency and relative errors compared with the NJOY results. A Godiva Benchmark is also used in order to test the ACE libraries produced by the new method. (authors)

Li, S.; Wang, K.; Yu, G. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

2012-07-01

436

Deeply virtual Compton Scattering cross section measured with CLAS  

SciTech Connect

The Generalized Parton Distributions (GPDs) provide a new description of nucleon structure in terms of its elementary constituents, the quarks and the gluons. Including and extending the information provided by the form factors and the parton distribution functions, they describe the correlation between the transverse position and the longitudinal momentum fraction of the partons in the nucleon. Deeply Virtual Compton Scattering (DVCS), the electroproduction of a real photon on a single quark in the nucleon eN --> e'N'g, is the exclusive process most directly interpretable in terms of GPDs. A dedicated experiment to study DVCS with the CLAS detector at Jefferson Lab has been carried out using a 5.9-GeV polarized electron beam and an unpolarized hydrogen target, allowing us to collect DVCS events in the widest kinematic range ever explored in the valence region : 1.0 < Q2 < 4.6 GeV2, 0.1 < xB < 0.58 and 0.09 < -t < 2.0 GeV2. In this paper, we show preliminary results of unpolarized cross sections and of polarized cross section differences for the DVCS channel.

Guegan, Baptistse [Institut de Physique Nucleaire, Orsay

2014-09-01

437

PWR Cross Section Libraries for ORIGEN-ARP  

SciTech Connect

New pressurized water reactor (PWR) cross-section libraries were generated for use with the ORIGEN-ARP depletion sequence in the SCALE nuclear analysis code system. These libraries are based on ENDF/B-VII nuclear data and were generated using the two-dimensional depletion sequence, TRITON/NEWT, in SCALE 6.1. The libraries contain multiple burnup-dependent cross-sections for seven PWR fuel designs, with enrichments ranging from 1.5 to 6 wt% 235U. The burnup range has been extended from the 72 GWd/MTU used in previous versions of the libraries to 90 GWd/MTU. Validation of the libraries using radiochemical assay measurements and decay heat measurements for PWR spent fuel showed good agreement between calculated and experimental data. Verification against detailed TRITON simulations for the considered assembly designs showed that depletion calculations performed in ORIGEN-ARP with the pre-generated libraries provide similar results as obtained with direct TRITON depletion, while greatly reducing the computation time.

McGraw, Carolyn [Texas A& M University; Ilas, Germina [ORNL

2012-01-01

438

Temperature dependent UV absorption cross sections for carbonyl sulfide  

NASA Technical Reports Server (NTRS)

The ultraviolet absorption spectrum of carbonyl sulfide is investigated in order to assess the importance of the photolytic sink for OCS in the troposphere. Absorption cross sections were measured at wavelengths between 185 and 300 nm in a double-beam spectrometer at temperatures of 295 and 225 K. The results are found to be in good agreement with previous reports in the short wavelength region, but significantly lower than the value of 2 x 10 to the 22nd sq cm/molecule proposed by Rudolf and Inn (1981) between 280 and 300 nm, which may be attributed to trace contaminants or dimerization. A marked temperature effect is noted at wavelengths greater than 240 nm and below 190 nm. As no evidence of absorption at wavelengths greater than 270 nm was found, estimates of the solar photodissociation rate of tropospheric OCS based on the present cross sections yield a value of about 2 x 10 to the -9th/sec, corresponding to a tropospheric lifetime of about 20 years. It is therefore concluded that solar photolysis represents a negligible sink for OCS.

Molina, L. T.; Lamb, J. J.; Molina, M. J.

1981-01-01

439

Cross-sectional neurotoxicology study of lead-exposed cohort  

SciTech Connect

Although the toxic effects of lead have been known for centuries, lead intoxication is still widespread in the United States. Without baseline tests of neuropsychological, neurobehavioral and neurophysiological testing it may be difficult to detect subtle changes in neurological function after lead exposure. This may be further confounded by partial chelation treatment and exposure to neurotoxic mixtures or inability to quantitate alcohol consumption. We undertook a cross-sectional study to address these problems in 24 exposed and 29 control subjects in a plant that manufactured electrical components using fritted leaded glass to coat capacitors and transistors. Potentially exposed workers had blood lead levels ranging between 3 micrograms/dL to 135 micrograms/dL. Industrial hygiene monitoring revealed the plant's air lead levels ranged from 61 micrograms/m3 to 1,700 micrograms/m3 in excess of OSHA permissible exposure limits of 40 micrograms/m3/10 hr day. Using a specially designed battery of neurophysiological, neurobehavioral and neuropsychological screening tests, we demonstrated a significant difference from controls in measures of psychomotor speed, motor strength and verbal memory. Although limited by the cross-sectional design, these findings support the hypothesis that the battery of neurophysiological, neuropsychological and neurobehavioral tests can detect a significant inter-group differences between lead-exposed and control subjects.

Pasternak, G.; Becker, C.E.; Lash, A.; Bowler, R.; Estrin, W.J.; Law, D. (San Francisco General Hospital, CA (USA))

1989-01-01

440

CCKT Calculation of e-H Total Cross Sections  

NASA Technical Reports Server (NTRS)

We are in the process of carrying out calculations of e-H total cross sections using the 'complex-correlation Kohn-T' (CCKT) method. In a later paper, we described the methodology more completely, but confined calculations to the elastic scattering region, with definitive, precision results for S-wave phase shifts. Here we extend the calculations to the (low) continuum (1 much less than k(exp 2) much less than 3) using a Green's function formulation. This avoids having to solve integro-differential equations; rather we evaluate indefinite integrals involving appropriate Green's functions and the (complex) optical potential to find the scattering function u(r). From the asymptotic form of u(r) we extract a T(sub L) which is a complex number. From T(sub L), elastic sigma(sub L)(elastic) = 4pi(2L+1)((absolute value of T(sub L))(exp 2)), and total sigma (sub L)(total) = 4pi/k(2L+1)Im(T(sub L)) cross sections follow.

Bhatia, Aaron K.; Schneider, B. I.; Temkin, A.; Fisher, Richard R. (Technical Monitor)

2002-01-01

441

Radar proves its worth in dam rehabilitation  

SciTech Connect

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.

NONE

1996-08-01

442

A compact fast-neutron producing target for high resolution cross section measurements  

Microsoft Academic Search

A proper knowledge of neutron cross sections is very important for the operation safety of various nuclear facilities. Reducing uncertainties in the neutron cross sections can lead to an enhanced safety of present and future nuclear power systems. Accurate neutron cross sections also play a relevant role in many other disciplines such as astrophysics, medicine, and security. Therefore it is

M. Flaska

2006-01-01

443

Giant resonance in the total photoabsorption cross section of Z ~ 90 nuclei  

Microsoft Academic Search

Total photoabsorption cross sections of 232Th, 235U, 238U and 239Pu have been measured in the giant resonance region by the absorption method. Measured cross sections were approximated by two Lorentz lines. Lorentz line parameters, integrated cross sections, deformation parameters and quadrupole moments are given. The analysis of the nuclear optical anisotropy evolution with the increase of Z shows that Z

G. M. Gurevich; L. E. Lazareva; V. M. Mazur; G. V. Solodukhov; B. A. Tulupov

1976-01-01

444

Curved thin-walled open-closed cross section beams with finite width  

Microsoft Academic Search

In this paper a consistent formulation of the static behaviour of circular beams with thin-walled open-closed cross section is presented. The influence of the different radius of curvature of each element of the cross section is taken into account, assuming the hypothesis of linear elasticity and that the distortion of the cross section is prevented. The warping shape function is

Lando Mentrasti

1995-01-01

445

PHYSICS OF NUCLEAR REACTORS Nuclear reactions and cross sections 1-10  

E-print Network

PHYSICS OF NUCLEAR REACTORS Nuclear reactions and cross sections 1-10 10 11 12 13 14 15 16 17 18 19 Theory, p. 392, 1970. #12;PHYSICS OF NUCLEAR REACTORS Nuclear reactions and cross sections 1-11 Where m 1.20 we get #12;PHYSICS OF NUCLEAR REACTORS Nuclear reactions and cross sections 1

Danon, Yaron

446

Orbital evolution of Geminids and Quadrantids by middle and upper atmosphere radar observations  

NASA Astrophysics Data System (ADS)

A meteor head echo is caused by radio waves scattering from the intense region of the plasma surrounding and co-moving with a meteoroid during atmospheric entry at about 70--130 km altitude. Meteor head echo observations were carried out using the high-power large-aperture (HPLA) Kyoto university Shigaraki middle and upper atmosphere (MU) radar in Japan (34.85° N, 136.10° E). The 46.5 MHz MU radar consisting of 475 crossed Yagi antennas has a nominal transmitter peak power of 1 MW and comprises a circular, phased-array antenna with a diameter of 103 m. The MU radar beam was pointed in the zenith direction with the field of view of ˜ 15°. Since 2009 the atmospheric trajectories and interplanetary orbital elements have been derived using the MU radar meteor head echoes (e.g. [1--3]). More than 140,000 sets of orbital elements of meteors were obtained until January 2014. Typical errors for velocity and perihelion distance are 0.25 km/s and 0.003 au, respectively. Such a huge number of meteoroid orbits with precise orbital accuracies has not been observed before. Here we report population of 2009--2013 Geminid and 2014 Quadrantid meteoroids. The orbits of Geminids' meteoroids, whose parent body is a comet-asteroid transition object (3200) Phaethon [4], were observed in 2009 (n=163), 2010 (n=310) and 2013 (n=513) whereas Quadrantids (n=223), whose parent body is 2003 EH_1 [5], were obtained in 2014. Figure shows radiant distributions (RA & DEC) and orbital elements (perihelion distance - eccentricity) of Geminids as a function of the Radar Cross Section (RCS) which is approximately a linear function of the log of electron line densities of a meteor trail corresponding to a meteoroid mass. The meteoroid orbital evolution of Geminids and Quadrantds considering Poynting-Robertson drag will be discussed compared with their parent bodies.

Abe, S.; Kero, J.; Nakamura, T.; Fujiwara, Y.; Watanabe, J.

2014-07-01

447

Models of radar imaging of the ocean surface waves  

Microsoft Academic Search

A number of models which would explain ocean wave imagery taken with a synthetic aperture imaging radar are analyzed analytically and numerically. Actual radar imagery is used to support some conclusions. The models considered correspond to three sources of radar backscatter cross section modulation:tilt modulation, roughness variation, and the wave orbital velocity. The effect of the temporal changes of the

CHARLES ELACHI

1977-01-01

448

Fast Neutron Inelastic Scattering Cross Sections in THORIUM-232.  

NASA Astrophysics Data System (ADS)

Fast neutron inelastic scattering cross sections for levels between 700-1550-keV excitation energy in the actinide nucleus, ('232)Th, have been measured using the (n,n') time-of-flight technique. Two series of measurements were undertaken using neutrons with a typical energy spread of 8-10 keV, generated by the ('7)Li(p,n)('7)Be reaction. These measurments for 125(DEGREES)-differential scattering cross sections were performed over the incident neutron energy regions of (i) 0.950-1.550 MeV, in 50-keV intervals with the time-of-flight spectrometer optimized to detect 0.200 -0.400-MeV scattered neutrons and (ii) 1.200-2.000 MeV, in 100-keV intervals with the time-of-flight spectrometer optimized to detect 0.400-0.800-MeV scattered neutrons. Over these scattered energy regions, an overall energy resolution of less than 15 keV was maintained. The relative neutron fluence was determined for each individual measurement, by positioning the main detector at 0(DEGREES) to view the primary neutron flux. Relative normalization was achieved by measuring the direct neutron flux from the lithium target with a fixed overhead monitor detector in both measurements. Main detector response was determined by comparison with a ('235)U fission chamber of known efficiency. Techniques for unfolding the complicated spectra obtained from these (n,n') studies were developed, employing user interactive computer codes to (i) generate simulated scattered neutron group response functions, (ii) subtract background effects from the measured spectra, (iii) approximate the background subtracted spectra in a weighted least-squares fashion by a superposition of response functions and (iv) make corrections for neutron absorption, finite scatterer size effects and multiple neutron scattering. Support codes consisting of graphics interaction packages, data file manipulation and transfer utility routines were created to assist in the spectral analysis procedure. Excitation function and angular distribution results were compared with (i) theoretical calculations that included both compound-nucleus and direct-interaction mechanisms, (ii) the Evaluated Nuclear Data File (ENDF-B/V) and (iii) previous (n,n') and (n,n'(gamma)) cross section measurements. Where applicable, estimates of electric monopole (EO) transition strengths were determined from these comparisons.

Ciarcia, Christopher Albert

449

On-Orbit Propulsion OMS/RCS  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the Space Shuttle's On-Orbit Propulsion systems: the Orbital Maneuvering System (OMS) and the Reaction Control System (RCS). The functions of each of the systems is described, and the diagrams of the systems are presented. The OMS/RCS thruster is detailed and a trade study comparison of non-toxic propellants is presented.

Hurlbert, Eric A.

2001-01-01

450

RCS - A System for Version Control  

Microsoft Academic Search

An important problem in program development and maintenance is version con- trol, i.e., the task of keeping a software system consisting of many versions and configurations well organized. The Revision Control System (RCS) is a software tool that assists with that task. RCS manages revisions of text documents, in particular source programs, documentation, and test data. It automates the storing,

Walter F. Tichy

1985-01-01

451

Requirements engineering for cross-sectional information chain models  

PubMed Central

Despite the wealth of literature on requirements engineering, little is known about engineering very generic, innovative and emerging requirements, such as those for cross-sectional information chains. The IKM health project aims at building information chain reference models for the care of patients with chronic wounds, cancer-related pain and back pain. Our question therefore was how to appropriately capture information and process requirements that are both generally applicable and practically useful. To this end, we started with recommendations from clinical guidelines and put them up for discussion in Delphi surveys and expert interviews. Despite the heterogeneity we encountered in all three methods, it was possible to obtain requirements suitable for building reference models. We evaluated three modelling languages and then chose to write the models in UML (class and activity diagrams). On the basis of the current project results, the pros and cons of our approach are discussed. PMID:24199080

Hübner, U; Cruel, E; Gök, M; Garthaus, M; Zimansky, M; Remmers, H; Rienhoff, O

2012-01-01

452

Neutron Cross Section Uncertainties in the Thermal and Resonance Regions  

SciTech Connect

In the 'Atlas of Neutron Resonances', special care was expended to ensure that the resonance parameter information reproduces the various measured thermal cross sections, as well as the infinite dilute resonance integrals for Z = 1-100. In contrast, the uncertainties of the recommended quantities do not match those generated from the uncertainties of the resonance parameters. To address this problem, the present study was initiated to achieve consistency for 15 actinides and 21 structural and coolant moderator materials. This is realized by assigning uncertainties to the parameters of the negative-energy resonances and changing, if necessary, significantly the uncertainties of the low-lying positive-energy resonances. The influence of correlations between parameters on the derived uncertainties is examined and discussed.

Mughabghab,S.F.; Oblozinsky, P.

2008-06-24

453

Stellar (n,gamma) cross section of 62Ni.  

PubMed

The 62Ni(n,gamma)63Ni(t(1/2)=100+/-2 yr) reaction plays an important role in the control of the flow path of the slow neutron-capture (s) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT=25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+/-2.8 mb, fairly consistent with a recent calculation, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62

Nassar, H; Paul, M; Ahmad, I; Berkovits, D; Bettan, M; Collon, P; Dababneh, S; Ghelberg, S; Greene, J P; Heger, A; Heil, M; Henderson, D J; Jiang, C L; Käppeler, F; Koivisto, H; O'Brien, S; Pardo, R C; Patronis, N; Pennington, T; Plag, R; Rehm, K E; Reifarth, R; Scott, R; Sinha, S; Tang, X; Vondrasek, R

2005-03-11

454

Low Energy Experimental Elastic Cross Sections for Medical Physics Application  

NASA Astrophysics Data System (ADS)

Elastic cross sections for electron energies below 10 MeV are fundamental quantities needed in treatment planning systems used at hospitals and health facilities. To date, there is very little if not no data within that energy regime. In collaboration with the high current, high energy resolution continuous electron beam of the Department of Energy's Jefferson Lab accelerator, we have performed a first stage of dedicated experiments with energies of 100-150 keV to collect data for this type of reactions. The targets used were gold, copper and