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1

Inductively Coupled Compact RFID Tag Antenna at 910 MHz With Near-Isotropic Radar Cross-Section (RCS) Patterns  

Microsoft Academic Search

This letter presents a compact (0.12 x 0.14lambda) RFID tag antenna which has near-isotropic radar cross-section (RCS) patterns and easy conjugate impedance matching property by virtue of an inductively coupled feeding. Its measured maximum and minimum RCS' are -17.3 dBm2 and -20.4 dBm2, respectively, with a difference of only 3.1 dB in all incident angles. The measured RCS' have been

Juno Ahn; Hyungmin Jang; Hyosang Moon; Jong-Wook Lee; Bomson Lee

2007-01-01

2

Terahertz radar cross section measurements.  

PubMed

We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar on full-size objects. The measurements are performed in a terahertz time-domain system with freely propagating terahertz pulses generated by tilted pulse front excitation of lithium niobate crystals and measured with sub-picosecond time resolution. The application of a time domain system provides ranging information and also allows for identification of scattering points such as weaponry attached to the aircraft. The shapes of the models and positions of reflecting parts are retrieved by the filtered back projection algorithm. PMID:21164990

Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

2010-12-01

3

Terahertz radar cross section measurements  

Microsoft Academic Search

We present the result of terahertz radar cross section measurements on various objects including models of aircraft fighters. Application of a time domain system provides both values of radar cross section and ranging information.

Krzysztof Iwaszczuk; Henning Heiselberg; Peter Uhd Jepsen

2010-01-01

4

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

5

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

6

Application of Bionics in Antenna Radar Cross Section Reduction  

Microsoft Academic Search

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

Wen Jiang; Ying Liu; Shuxi Gong; Tao Hong

2009-01-01

7

Radar Cross Section Models for Limited Aspect Angle Windows.  

National Technical Information Service (NTIS)

This thesis presents a method for building Radar Cross Section (RCS) models of aircraft based on static data taken from limited aspect angle windows. These models statistically characterize static RCS. This is done to show that a limited number of samples...

M. C. Robinson

1992-01-01

8

Radar cross-section analysis of wind turbine blades with radar absorbing materials  

Microsoft Academic Search

Wind turbines interfere with radar systems due to their large radar cross-section (RCS) and the rotation of the blades. Applying radar absorbing materials (RAM) is considered as a possible mitigation measure. This paper will present RCS modeling results of a generic 40 meters blade. The blade is segmented into 4 sections and the monostatic scattering from each section is modeled.

L. S. Rashid; A. K Brown

2011-01-01

9

Comparison of Computational Electromagnetic Codes for Prediction of Low- Frequency Radar Cross Section.  

National Technical Information Service (NTIS)

Radar cross section (RCS) prediction of full-scale aircraft is of interest to military planners for a variety of applications. Several computational electromagnetic codes for RCS prediction are available with differing features and capabilities. The goal ...

P. C. Lash

2006-01-01

10

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

11

Radar absorbing material (RAM) and shaping on radar cross section reduction of dihedral corners  

Microsoft Academic Search

How far can a radar system detect an object depends the radar cross section (RCS) of the target. Corner reflectors are the major scattering centers in the radar signatures of vehicles. The monostatic return from such structures can be reduced by ensuring that surfaces never meet at right angles and by application of radar absorbing materials (RAM). This paper deals

G. G. Peixoto; A. L. de Paula; L. A. Andrade; C. M. A. Lopes; M. C. Rezende

2005-01-01

12

Thin AMC Structure for Radar Cross-Section Reduction  

Microsoft Academic Search

A thin artificial magnetic conductor (AMC) structure is designed and breadboarded for radar cross-section (RCS) Reduction applications. The design presented in this paper shows the advantage of geometrical simplicity while simultaneously reducing the overall thickness (for the current design ). The design is very pragmatic and is based on a combination of AMC and perfect electric conductor (PEC) cells in

Maurice Paquay; Juan-Carlos Iriarte; Iñigo Ederra; Ramon Gonzalo; Peter de Maagt

2007-01-01

13

The Decrease of the Radar Cross Section of Hypersonic Model  

Microsoft Academic Search

To research the effect of plasma, the radar cross section (RCS) of a hypersonic model is measured in our light gas gun. The spectrum of the received signal and one-dimensional radar image of the model are given. According to this experiment, three-dimensional (3-D) finite-difference time-domain (FDTD) simulations are performed for calculating microwave scattering from a plasma-cloaked conducting model.

Yu Zhefeng; Bu Shaoqing; Liu Sen; Zeng Xuejun; Ma Ping; Shi Anhua

2007-01-01

14

A technique for the rapid measurement of bistatic radar cross sections  

Microsoft Academic Search

Numerous techniques for measuring monostatic (backscatter) radar cross sections (RCS) are well known, but bistatic RCS measurements are inherently more difficult. In this paper we describe a bistatic RCS measurement technique which circumvents the major obstacles. It uses a variation of the CW \\

J. F. Hunka; R. Stovall; D. Angelakos

1977-01-01

15

Extended Characterisation Of A UHF Direction Finding Antenna With Optimised Radar Cross Section  

Microsoft Academic Search

In R. Mueller et. al. (2006) the design of a UHF direction finding antenna with optimised radar cross section (RCS) was introduced. In the present paper the monostatic RCS of the antenna is characterised up to 18 GHz. Measured results of the RCS are compared to simulated results which are obtained using the new commercially available multilevel fast multipole method

Rainer Mueller; Ralf Lorch; Wolfgang Menzel

2007-01-01

16

Radar cross section models for limited aspect angle windows  

NASA Astrophysics Data System (ADS)

This thesis presents a method for building Radar Cross Section (RCS) models of aircraft based on static data taken from limited aspect angle windows. These models statistically characterize static RCS. This is done to show that a limited number of samples can be used to effectively characterize static aircraft RCS. The optimum models are determined by performing both a Kolmogorov and a Chi-Square goodness-of-fit test comparing the static RCS data with a variety of probability density functions (pdf) that are known to be effective at approximating the static RCS of aircraft. The optimum parameter estimator is also determined by the goodness of-fit tests if there is a difference in pdf parameters obtained by the Maximum Likelihood Estimator (MLE) and the Method of Moments (MoM) estimators.

Robinson, Mark C.

1992-12-01

17

On the meteoric head echo radar cross section angular dependence  

NASA Astrophysics Data System (ADS)

We present radar cross section (RCS) measurements of meteor head echoes observed with the tristatic 930 MHz EISCAT UHF radar system. The three receivers offer a unique possibility to accurately compare the monostatic RCS of a meteor target with two simultaneously probed bistatic RCSs at different aspect angles. Meteoroids from all possible directions entering the common volume monitored by the three receivers are detected, out to an aspect angle of 130° from the meteoroid trajectories. The RCS of individual meteors as observed by the three receivers are equal within the accuracy of the measurements. This is consistent with an essentially isotropic scattering process as has previously been inferred from polarization measurements by S. Close et al. (2002). There is a very weak trend present in our data suggesting that the RCS may decrease at a rate of 0.2 dB per 10° with increasing aspect angle.

Kero, J.; Szasz, C.; Wannberg, G.; Pellinen-Wannberg, A.; Westman, A.

2008-04-01

18

Radar cross sections for mesospheric echoes at Jicamarca  

NASA Astrophysics Data System (ADS)

Radar cross sections (RCS) of mesospheric layers at 50 MHz observed at Jicamarca, Peru, range from 10-18 to 10-16 m-1, three orders of magnitudes smaller than cross sections reported for polar mesospheric winter echoes during solar proton events and six orders of magnitude smaller than polar mesospheric summer echoes. Large RCS are found in thick layers around 70 km that also show wide radar spectra, which is interpreted as turbulent broadening. For typical atmospheric and ionospheric conditions, volume scattering RCS for stationary, homogeneous, isotropic turbulence at 3 m are also in the range 10-18 to 10-16 m-1, in reasonable agreement with measurements. Moreover, theory predicts maximum cross sections around 70 km, also in agreement with observations. Theoretical values are still a matter of order-of-magnitude estimation, since the Bragg scale of 3 m is near or inside the viscous subrange, where the form of the turbulence spectrum is not well known. In addition, steep electron density gradients can increase cross-sections significantly. For thin layers with large RCS and narrow spectra, isotropic turbulence theory fails and scattering or reflection from anisotropic irregularities may gain relevance.

Lehmacher, G. A.; Kudeki, E.; Akgiray, A.; Guo, L.; Reyes, P.; Chau, J.

2009-07-01

19

Analysis of Radar Cross Section Measurements of a Scale Model of the MQM-34D.  

National Technical Information Service (NTIS)

Monostatic radar cross section (RCS) measurements of a half scale model of the MQM-34D target drone are reduced and analyzed for vertical principal circular, and cross circular polarizations. The vertically polarized measurements are also compared with RC...

J. W. Wright

1975-01-01

20

An improved physical optics method for the computation of radar cross section of electrically large objects  

Microsoft Academic Search

An improved physical optics method for the computation of radar cross section of electrically large objects is presented. The method is quite general to compute the radar cross section (RCS) of arbitrarily shaped metal structures by rigorously transforming the radiation surface integral in the traditional PO method to a line integral along the metal boundary. Since the line integral is

Chonghua Fang; Xiaonan Zhao; Qian Liu

2008-01-01

21

USING GENETIC ALGORITHM TO REDUCE THE RADAR CROSS SECTION OF THREE-DIMENSIONAL ANISOTROPIC IMPEDANCE OBJECT  

Microsoft Academic Search

This paper focuses on the radar cross section (RCS) reduction for the three-dimensional object with anisotropic impedance coating. In this work, a genetic algorithm is adopted to optimize the RCS of the anisotropic impedance object in desired angle range. The surface impedances are considered as the optimized parameters and the scattering of the object is computed by the PO method.

Hai Tao Chen; Guo-Qiang Zhu; Si-Yuan He

2008-01-01

22

Analysis of radar cross section measurements of a scale model of the MQM-34D  

Microsoft Academic Search

Monostatic radar cross section (RCS) measurements of a half scale model of the MQM-34D target drone are reduced and analyzed for vertical principal circular, and cross circular polarizations. The vertically polarized measurements are also compared with RCS measurements of a full-scale drone. The RCS measurements are reduced on a cut-by-cut basis and on an aspect angle region basis. The former

J. W. Wright

1975-01-01

23

On using significant wave height and radar cross section to improve radar altimeter measurements of wind speed  

Microsoft Academic Search

Wind blowing across the ocean surface generates small, centimeter scale roughness. The radar cross section (RCS) measured by spaceborne, nadir-looking altimeters operating at about 13.5 GHz is responsive to this roughness. Present altimeter algorithms use RCS to infer wind speed. We compare Geosat altimeter estimates of wind speed and nearly coincident estimates from NOAA data buoys to determine whether altimeter

Frank Monaldo; Ella Dobson

1989-01-01

24

Automation of an RCS (Radar Cross Section) Measurement System and Its Application to Investigate the Electromagnetic Scattering from Scale Model Aircraft Canopies.  

National Technical Information Service (NTIS)

The purpose of this study was twofold. The first objective was to complete the development of AFIT's Far-Field Radar Range with a fully automated measurement process. The second objective was to use the facility to investigate the scattering of metallic v...

S. A. Owens

1989-01-01

25

Automation of an RCS (Radar Cross Section) measurement system and its application to investigate the electromagnetic scattering from scale model aircraft canopies  

Microsoft Academic Search

The purpose of this study was twofold, the first objective was to complete the development of AFIT's Far-Field Radar Range with a fully automated measurement process. The second objective was to use the facility to investigate the scattering of metallic versus transparent aircraft canopies relative to the scattering of the total aircraft. The approach for the investigation was: (1) to

Scott A. Owens

1989-01-01

26

Radar cross section statistics of cultural clutter at Ku-band  

NASA Astrophysics Data System (ADS)

Knowing the statistical characteristics of the radar cross-section (RCS) of man-made, or cultural clutter, is crucial to the success of clutter mitigation, radar target detection algorithms, and radar system requirements in urban environments. Open literature studies regarding the statistical nature of cultural clutter focus primarily on radar probability models or limited experimental data analysis of specific locations and frequencies. This paper seeks to expand the existing body of work on cultural clutter RCS statistics at Ku-band for ground moving target indication (GMTI) and synthetic aperture radar (SAR) applications. We examine the normalized RCS probability distributions of cultural clutter in several urban scenes, across aspect and elevation angle, for vertical transmit/receive (VV) polarizations, and at diverse resolutions, using experimental data collected at Ku-band. We further describe frequency and RCS strength statistics of clutter discretes per unit area to understand system demands on radars operating in urban environments in this band.

Raynal, Ann Marie; Bickel, Douglas L.; Dubbert, Dale F.; Verge, Tobias J.; Burns, Bryan L.; Dunkel, Ralf; Doerry, Armin W.

2012-05-01

27

Scaled Bistatic Radar Cross Section Measurements of Aircraft With a Fiber-Coupled THz Time-Domain Spectrometer  

Microsoft Academic Search

The knowledge of the radar cross section (RCS) of aircraft and other objects is of great interest both for civil and military applications. Scaled setups are often used in order to facilitate RCS measurements in a well-defined laboratory environment. As radar frequencies steadily increase, for high scaling factors these measurements have to be carried out in the THz regime. In

Ralf Gente; Christian Jansen; Robert Geise; Ole Peters; Michael Gente; Norman Krumbholz; Christoph Moller; Stefan Busch; Martin Koch

2012-01-01

28

Lunar Radar Cross Section at Low Frequency  

NASA Astrophysics Data System (ADS)

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

29

Transient ultra wide band measurement applications: radar cross section, synthetic aperture radar, electromagnetic compatibility  

Microsoft Academic Search

The Electronic Armament Centre (CELAR: Centre d'Electronique de L'Armement) and the Research Institute of Microwave and Optical Communications (IRCOM: Institut de Recherches en Communications Optiques et Micro-ondes) has evaluated the use of ultra-wide-band (UWB) short pulse measurement facilities to characterize target electromagnetic signatures. A first device is capable of determining the radar cross section (RCS) within a 200 MHz to

J. Andrieu; C. Dubois; M. Lalande; V. Bertrand; P. Delmote; B. Beillard; E. Martinod; B. Jecko; R. Guilleret; F. Monnier; M. Legoff

2003-01-01

30

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

Microsoft Academic Search

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

Bhaskar Chaudhury; Shashank Chaturvedi

2009-01-01

31

Experimental Facility for Measuring Aircraft Inlet\\/Engine Radar Cross Section  

Microsoft Academic Search

A full-size aircraft engine-duct mock-up experimental apparatus has been built to collect cavity radar cross section (RCS) data on aircraft engine inlets. The engine-duct structure is made up of a cylindrical duct with a single fan stage consisting of 30 generic straight fan blades. Experimental results indicate that the azimuthal RCS patterns from the engine-duct are quite complex. Numerical computations

S. Wong; E. Riseborough; G. Duff; K. K. Chan

32

Simulation of multistatic and backscattering cross sections for airborne radar  

Microsoft Academic Search

In order to determine susceptibilities of airborne radar to electronic countermeasures and electronic counter-countermeasures simulations of multistatic and backscattering cross sections were developed as digital modules in the form of algorithms. Cross section algorithms are described for prolate (cigar shape) and oblate (disk shape) spheroids. Backscattering cross section algorithms are also described for different categories of terrain. Backscattering cross section

Albert W. Biggs

1986-01-01

33

RCS evaluation of complex objects coated with radar absorbing materials using the complex ray method  

Microsoft Academic Search

The strategy and results of an RCS (radar cross section) evaluation of a dihedral corner reflector coated with lossy materials using the complex ray method are described. A computer program based on the analysis presented has been developed to perform effective RCS calculations of dihedral corner reflectors having the inner surfaces coated with or without radar adsorbing materials. One of

Y. Z. Ruan; H. P. Du

1992-01-01

34

Radar cross section statistics of ground vehicles at Ku-band  

NASA Astrophysics Data System (ADS)

Knowing the statistical characteristics of a target's radar cross-section (RCS) is crucial to the success of radar target detection algorithms. Open literature studies regarding the statistical nature of the RCS of ground vehicles focus primarily on simulations, scale model chamber measurements, or limited experimental data analysis of specific vehicles at certain frequencies. This paper seeks to expand the existing body of work on ground vehicle RCS statistics at Ku-band for ground moving target indication (GMTI) applications. We examine the RCS probability distributions of civilian and military vehicles, across aspect and elevation angle, for HH and VV polarizations, and at diverse resolutions, using experimental data collected at Ku-band. We further fit Swerling target models to the distributions and suggest appropriate detection thresholds for ground vehicles in this band.

Raynal, Ann Marie; Bickel, Douglas L.; Denton, Michael M.; Bow, Wallace J.; Doerry, Armin W.

2011-05-01

35

Development of a Chaff Cloud RCS Measurement Radar at 94.5 GHz  

Microsoft Academic Search

The Radar Cross Section (RCS) signature of the chaff cloud in the millimeter wave band is useful in many research fields such\\u000a as radar countermeasure, target identification and discrimination, and so on. To obtain the RCS of the chaff cloud, practical\\u000a measurement is an effective method. This paper introduces the design and implementation of a bistatic radar which is used

Lin Zou; Xuegang Wang; Lu Qian

2010-01-01

36

Planar near-field scanning for compact range bistatic radar cross-section measurement  

NASA Astrophysics Data System (ADS)

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.

1991-11-01

37

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

38

Statistics of Radar Cross Section Scintillations  

Microsoft Academic Search

The appropriateness of the two-parameter beta distribution as a characterization of RCS scintillation for a complex target is developed and discussed with particular attention to evidence afforded by experimental data. Distributions of measured data supplied to the authors by the Boeing Corporation for the 727-100C aircraft and by Dynalectron Corporation for the RATSCAT-measured drone are compared with Rayleigh, chi-square. log-normal,

J. W. Follin Jr; F. C. Paddison; A. L. Maffett

1984-01-01

39

High-frequency RCS of complex radar targets in real-time  

Microsoft Academic Search

This paper presents a new and original approach for computing the high-frequency radar cross section (RCS) of complex radar targets in real time with a 3-D graphics workstation. The aircraft is modeled with I-DEAS solid modeling software using a parametric surface approach. High-frequency RCS is obtained through physical optics (PO), method of equivalent currents (MEC), physical theory of diffraction (PTD),

Juan M. Rius; Miguel Ferrando; Luis Jofre

1993-01-01

40

Computation of RCS from a flat plate covered with radar absorbing material  

Microsoft Academic Search

Since the early 1980s, the electromagnetic stealth technique has been developed for reducing the radar cross section (RCS) of aircraft based on two principal methods. One is to cover the aircraft with a radar absorbing material (RAM), the other is to modify the aircraft shape. The scattering from an arbitrary flat plate of electrically large dimensions and coated with a

Liang Chao Wu; Wen Xun Zhang; Mao Guang Wang

1995-01-01

41

Radar Cross Section of a rectangular waveguide array with complex load and covered with dielectric  

NASA Astrophysics Data System (ADS)

The Radar Cross Section (RCS) of an open waveguide array, periodic in its two dimensions, is calculated by the moments method. The field is expanded in free space on a set of Floquet modes and in the waveguides on the set of usual guided modes. Waveguides may be filled and covered with different dielectrics. The model takes the presence of phase shifters into account. In this paper, the software which gives the power radiated in free space is validated by experimental results. We use it to evaluate scattering as a function of mismatching before and after the phase shifters. This software can be used for radiation pattern optimization as well as for RCS evaluation over a large frequency band.

Marty, V.; Combes, P. F.; Borderies, P.

42

Reduction of radar cross section by multiple passive impedance loadings  

NASA Astrophysics Data System (ADS)

A general formulation to reduce scattering from conducting objects by multiple passive impedance loadings (MPILs) is derived. Computer programs to reduce the bistatic radar cross section for arbitrarily shaped thin-wire scatterers by MPILs have been developed. Some calculated results for a straight wire, a circular loop, and a rectangular wire frame are shown. It is found that multiple loadings are much more effective to control scattering than a single loading.

Hirasawa, Kazuhiro

1987-04-01

43

A robust algorithm for automated target recognition using precomputed radar cross sections  

NASA Astrophysics Data System (ADS)

Passive radar is an emerging technology that offers a number of unique benefits, including covert operation. Many such systems are already capable of detecting and tracking aircraft. The goal of this work is to develop a robust algorithm for adding automated target recognition (ATR) capabilities to existing passive radar systems. In previous papers, we proposed conducting ATR by comparing the precomputed RCS of known targets to that of detected targets. To make the precomputed RCS as accurate as possible, a coordinated flight model is used to estimate aircraft orientation. Once the aircraft's position and orientation are known, it is possible to determine the incident and observed angles on the aircraft, relative to the transmitter and receiver. This makes it possible to extract the appropriate radar cross section (RCS) from our simulated database. This RCS is then scaled to account for propagation losses and the receiver's antenna gain. A Rician likelihood model compares these expected signals from different targets to the received target profile. We have previously employed Monte Carlo runs to gauge the probability of error in the ATR algorithm; however, generation of a statistically significant set of Monte Carlo runs is computationally intensive. As an alternative to Monte Carlo runs, we derive the relative entropy (also known as Kullback-Liebler distance) between two Rician distributions. Since the probability of Type II error in our hypothesis testing problem can be expressed as a function of the relative entropy via Stein's Lemma, this provides us with a computationally efficient method for determining an upper bound on our algorithm's performance. It also provides great insight into the types of classification errors we can expect from our algorithm. This paper compares the numerically approximated probability of Type II error with the results obtained from a set of Monte Carlo runs.

Ehrman, Lisa M.; Lanterman, Aaron D.

2004-09-01

44

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

45

Improvements to the finite-difference time-domain method for calculating the radar cross section of a perfectly conducting target  

Microsoft Academic Search

Several improvements to the finite-difference time-domain (FDTD) method for calculating the radar cross section (RCS) of a perfectly conducting target are presented. Sinusoidal and pulsed FDTD excitations are compared to determine an efficient method of finding the frequency response of targets. The maximum cell size, the minimum number of external cells, and a method to eliminate field storage in the

C. M. Furse; S. P. Mathur; O. P. Gandhi

1990-01-01

46

Radar-cross-section measurement errors caused by test object interaction with low-dielectric-constant supports  

NASA Astrophysics Data System (ADS)

In the search for an ideal test-object support for simulated free-space radar-cross-section (RCS) measurements, low-density polystyrene foam has achieved considerable popularity. However, significant error can be introduced into a measurement by the use of an inappropriately designed support. Although low back-scatter radar cross section (RCS) can be obtained with this material, interactions can occur between the test object and the mount which will cause measurement errors in excess of several dB. We present results of measurements performed on a simple test object supported on a low-density foam column which demonstrate this effect. As we discuss, this error can be incorrectly interpreted to be caused by poor alignment of the test object with the radar-range coordinate system. Finally, we show that the error can be explained by differential propagation effects. In addition, this simple theory provides the insight necessary to devise appropriate measures to minimize the errors caused by the presence of the support.

Brock, B. C.; Patitz, W. E.; Sorensen, K. W.; Zittel, D. H.

47

Radar-cross-section measurement errors caused by test object interaction with low-dielectric-constant supports  

NASA Astrophysics Data System (ADS)

In the search for an ideal test-object support for simulated free-space radar-cross-section (RCS) measurements, low-density polystyrene foam has achieved considerable popularity. However, significant error can be introduced into a measurement by the use of an inappropriately designed support. Although low backscatter radar-cross-section (RCS) can be obtained with this material, interactions can occur between the test object and the mount which will cause measurement errors in excess of several dB. We present results of measurements performed on a simple test object supported on a low-density foam column which demonstrate this effect. As we discussed, this error can be incorrectly interpreted to be caused by poor mechanical alignment of the test object with the radar-range coordinate system. We discuss trade-offs associated with the choice between electrical and mechanical boresighting of the test object. Finally, we show that the error can be explained by differential propagation effects. In addition, this simple theory provides the insight necessary to devise appropriate measures to minimize the errors caused by the presence of the support.

Brock, B. C.; Patitz, W. E.; Sorensen, K. W.; Zittel, D. H.

1991-08-01

48

Radar-cross-section modeling of a waveguide array  

NASA Astrophysics Data System (ADS)

The RCS of a two-dimensionally periodic open waveguide array is calculated by the method of moments. The field is expanded in Floquet modes in free space and following the natural modes in the waveguides. In the case considered, the first scattered mode gives rise to a significant bistatic RCS which becomes monstatic at a given frequency. Depending on the permittivity of the dielectric in the waveguides and the matching of higher-order modes, the RCS can be quite variable and its value can become very low.

Marty, Viviane; Borderies, P.; Combes, P. F.

49

Radar Cross-Section of Damped Cylinders and Dielectric Strips.  

National Technical Information Service (NTIS)

This report presents 2D RCS (echo width) calculations for electrically and magnetically conducting circular cylinders with and without an electromagnetically damping coat. Similar calculations for dielectric cylinders and thin dielectric strips are also g...

R. Holland K. S. Cho

1986-01-01

50

Radar Cross-Section Evaluation of Arbitrary Cylinders.  

National Technical Information Service (NTIS)

This report presents 2D monostatic and bistatic RCS (echo width) calculations for electrically and magnetically conducting circular cylinders with and without an electromagnetically damping coat. Similar calculations for dielectric cylinders and thin diel...

R. Holland K. S. Cho

1986-01-01

51

Radar Cross Section Measurements of the Improved BQM-34A Collocated Augmentation Scoring System.  

National Technical Information Service (NTIS)

Data were acquired to define the I-band radar cross section and glint characteristics of the Improved BQM-34A CAS (target drone equipped with Collocated active radar Augmentation Scoring System). Monostatic and bistatic radar measurements were made on a f...

M. R. Smith

1978-01-01

52

An Extension of the Modified Geometrical Optics Methods for Radar Cross Sections of Dielectric Bodies.  

National Technical Information Service (NTIS)

The radar cross section of a dielectric sphere whose relative dielectric constant is significantly greater than unity is computed by means of the modified geometrical optics method. A new technique is introduced for treating the on-axis, internally reflec...

T. Kawano L. Peters

1964-01-01

53

A UHF Direction Finding Antenna with Optimised Radar Cross Section  

Microsoft Academic Search

The presented results show that the simulation with a modern simulation tool using methods of moments agree very well with the measurements of a prototype. Furthermore it is shown that the monostatic RCS of a UHF DF antenna can be successfully reduced without degrading the DF performance

Rainer Mueller; Ralf Lorch; Wolfgang Menzel

2006-01-01

54

Radar cross section measurements (8-12 GHz) of flat plates painted with microwave absorbing materials  

Microsoft Academic Search

The aim of the present work is to present radar cross section measurements of flat plates painted with radar absorbing material (RAM) in the range of 8-12 GHz. The measurements were carried out in an anechoic chamber at Centro Tecnico Aeroespacial (CTA)-Ministerio da Defesa facilities, and the RAM coating was manufactured at Divisao de Materiais of Instituto de Aeronautica e

M. C. Rezende; I. M. Martin; M. A. S. Miacci; E. L. Nohara

2001-01-01

55

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

Microsoft Academic Search

The normalized radar cross section of the sea for backscatter, ?o, is investigated for incidence angles between 0° and 89° using data collected over more than two decades. The most recent measurements were made from several ships using a coherent, dual-polarized, X band radar. These measurements show that vertically polarized transmit and receive signals, ?o(VV), at high incidence angles exhibit

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

2010-01-01

56

Modeling Plasma Effects on Radar Cross Section of Reentry Vehicles  

Microsoft Academic Search

In order to design a radar to detect, track, and identify unknown targets, models of the expected electromagnetic scattering properties of the targets must be developed. This communication begins with a qualitative

W. R. Mahaffey; R. F. Jacob

1969-01-01

57

Design of transmission-type phase holograms for a compact radar-cross-section measurement range at 650 GHz  

NASA Astrophysics Data System (ADS)

A design formalism is presented for transmission-type phase holograms for use in a submillimeter-wave compact radar-cross-section (RCS) measurement range. The design method is based on rigorous electromagnetic grating theory combined with conventional hologram synthesis. Hologram structures consisting of a curved groove pattern on a 320 mm×280 mm Teflon plate are designed to transform an incoming spherical wave at 650 GHz into an output wave generating a 100 mm diameter planar field region (quiet zone) at a distance of 1 m. The reconstructed quiet-zone field is evaluated by a numerical simulation method. The uniformity of the quiet-zone field is further improved by reoptimizing the goal field. Measurement results are given for a test hologram fabricated on Teflon.

Noponen, Eero; Tamminen, Aleksi; Vaaja, Matti

2007-07-01

58

Radar cross section measurements of the improved BQM-34A collocated augmentation scoring system  

Microsoft Academic Search

Data were acquired to define the I-band radar cross section and glint characteristics of the Improved BQM-34A CAS (target drone equipped with Collocated active radar Augmentation Scoring System). Monostatic and bistatic radar measurements were made on a flight worthy BQM-34A. This report provides a summary of the measurement conditions and reproductions of test plots obtained. Also included are reproductions of

M. R. Smith

1978-01-01

59

On radar cross-section of the Sun during earthward-directed CME  

NASA Astrophysics Data System (ADS)

In order to design radar experiments for the study of the Sun, it is necessary to make some preliminary estimates. We report results of crude calculations of the solar radar cross section during the appearance of a geoeffective CME. For the calculations, we consider the CME to be a spherical expanding plasma shell with a constant mass moving towards the Earth. Two approximations --- ``mirror reflection'' and ``volume scattering'' --- were used. The dependence of the radar cross-section on amount of mass ejected, expansion speed, velocity of the motion away from the Sun, as well as sounding frequency were obtained. In the ``mirror reflection'' model during geoeffective CME the cross-section should first drops at the moment when the CME leading edge achieves the critical level in the solar corona, at which plasma frequency is equal to the sounding frequency. Then the cross-section slowly increases until the decreasing plasma frequency at the leading edge of the expanding CME becomes less then the sounding frequency. After this, the cross-section attains the value for the quiet Sun. For the ``volume scattering'' model a decrease of the gross section after the leading edge achievement of the critical level is much slower. The effect described could be observed by a solar radar operating in approximate frequency range 10--50 MHz. Criteria of the CME geoefficiency determination with the use of solar radaring are discussed on the base of the results obtained.

Belov, Yu. I.; Grach, S. M.; Rodriguez, P.; Thide, B.; Tokarev, Yu. V.

2003-04-01

60

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

61

Simulations and measurements of a radar cross section of a Boeing 747-200 in the 20-60 MHz frequency band  

NASA Astrophysics Data System (ADS)

HF and VHF low frequency bands provide a promising way to perform radar target recognition. At these frequencies, Radar Cross Section (RCS) behavior is not well known because the scattered field is due to a complex phenomenon where the interactions between the different parts of the structure have a significant contribution, which makes the prediction difficult. A wire model of a commercial Boeing 747-200 aircraft, developed to be used with the Numerical Electromagnetic Code (NEC), is presented. The reliability of this model has been assessed by comparing the results given by NEC with the measurements made in an anechoïc chamber with a scaled aircraft, and a relatively good agreement was observed between simulations and measurements. The RCS variations of an aircraft along different flight routes have been investigated, and it is shown that it is necessary to know the flight route of the airplane to envisage target identification in spite of the use of the low frequency band.

David, A.; Brousseau, C.; Bourdillon, A.

2003-08-01

62

Simulations of the radar cross section of a generic air-to-air missile coated with radar absorbing materials  

Microsoft Academic Search

Simulations of the radar cross section of a heat- seeking air-to-air missile model were performed using the CADRCS software. In these simulations at a frequency of 10 GHz, the surface of the missile was considered to be a perfect conductor and to be coated with a radar absorbing material (RAM). The comparison of results from the simulations shows how different

Mauro A. Alves; Guilherme G. Peixoto; Mirabel C. Rezende

2007-01-01

63

Analytical study of the bistatic radar cross-section of a prolate spheroid  

NASA Astrophysics Data System (ADS)

Bistatic radar has important application in strategic and tactical space surveillance and in weapon tracking. At the present time, there is a lack of standard techniques for measuring radar cross sections. This effort was a feasibility study into obtaining an exact radar cross section for the Advanced Strategic Air Launched Missile (ASALM). The study was limited to the bistatic cross section of a typical target. A prolate spheroid was selected because it resembles an air cruise missile. Results were configured in the form of bistatic cross sections with a computer program to generate additional cross sections for prolate spheroids with different major to minor axis ratios. Any surface that is convex at each point, and which has no two distinct points where the outward normal vectors are in the same direction, can be handled similarly. Hence, the program written could very quickly be changed to handle a figure that is ellipsoidal in all the major planes, or even a parabola of revolution that extends to infinity in one direction. It is simple a matter of being able mathematically to describe the surface.

Biggs, A. W.; McMillian, S. B.

1980-03-01

64

Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar  

NASA Astrophysics Data System (ADS)

The Resolute Bay VHF radar, located in Nunavut, Canada (75.0° N, 95.0° W) and operating at 51.5 MHz, has been used to investigate Polar Mesosphere Summer Echoes (PMSE) since 1997. PMSE are a unique form of strong coherent radar echoes, and their understanding has been a challenge to the scientific community since their discovery more than three decades ago. While other high latitude radars have recorded strong levels of PMSE activities, the Resolute Bay radar has observed relatively lower levels of PMSE strengths. In order to derive absolute measurements of PMSE strength at this site, a technique is developed to determine the radar efficiency using cosmic (sky) noise variations along with the help of a calibrated noise source. VHF radars are only rarely calibrated, but determination of efficiency is even less common. Here we emphasize the importance of efficiency for determination of cross-section measurements. The significant advantage of this method is that it can be directly applied to any MST radar system anywhere in the world as long as the sky noise variations are known. The radar efficiencies for two on-site radars at Resolute Bay are determined. PMSE backscatter cross-section is estimated, and decade-long PMSE strength variations at this location are investigated. It was noticed that the median of the backscatter cross-section distribution remains relatively unchanged, but over the years a great level of variability occurs in the high power tail of the distribution.

Swarnalingam, N.; Hocking, W. K.; Argall, P. S.

2009-04-01

65

Low-Radar-Cross-Section OH-6A Helicopter Tail Rotor Blade.  

National Technical Information Service (NTIS)

The design, fabrication, and testing results of a low-radar-cross-section (LRCS) filament-wound composite tail rotor blade for the OH-6A helicopter are reported. Two tull-scale blades and four 12-inch-long blade sections were fabricated during the program...

S. Yao D. Abildskov

1974-01-01

66

Scaled radar cross section measurements with terahertz-spectroscopy up to 800 GHz  

Microsoft Academic Search

Radar cross section measurements of complex, large objects (e.g. aircraft) are usually performed on miniaturized models, as this enables a well controllable measurement environment. The system frequency in the scaled scenario is proportional to the inverse size ratio of the model compared to the original object. If a high scaling factor is required to accommodate the measurement setup in a

C. Jansen; N. Krumbholz; R. Geise; A. Enders; M. Koch

2009-01-01

67

RCS and read range of a UHF RFID tag  

Microsoft Academic Search

The development of a novel RFID tag operating at 869 MHz and its performance evaluation using simulated Radar Cross Section (RCS) are presented. The RCS variations of the tag antenna are evaluated over azimuth and elevation angular ranges for three cases of load: short, matched load and open. The tag exhibits appreciably good differential RCS between its switching states over

Thomaskutty Mathew; M. A. Ziai; John Batchelor

2010-01-01

68

An upper bound on the solar radar cross section at 50 MHz  

NASA Astrophysics Data System (ADS)

We have made 16 unsuccessful attempts, in February and October 2003, and February 2004, to observe solar echoes using the 50 MHz radar at Jicamarca in Peru. The upper bound that we have determined on the solar cross section is significantly lower than the average of earlier reported observations. In this paper we will describe the observations, discuss the noise and interference from solar bursts, and suggest possible reasons why the echo might be weaker than expected.

Coles, W. A.; Harmon, J. K.; Sulzer, M. P.; Chau, J. L.; Woodman, R. F.

2006-04-01

69

Experimental study on human breathing cross section using UWB impulse radar  

Microsoft Academic Search

Human being detection in post-disaster scenarios using UWB radars relies on detection of slight variations in time-of-arrival of the backscattered response due to human breathing motion. In this study we investigate experimentally the human breathing cross-section (BCS) in the UWB frequency band as function of aspect angle for three positions of the body and three combinations of antenna-pair polarization. Due

Amer Nezirovic; Solomon Tesfay; A. S. E. Valavan; A. Yarovoy

2008-01-01

70

The modulation of the radar cross section of the ocean surface by an azimuthally traveling long gravity wave  

Microsoft Academic Search

A new technique is used to calculate the modulation of the radar cross section of the ocean surface by a long gravity wave having a single narrow-band spectral peak. Spectral analysis of the measured wave height time series is used to determine the position on the dominant wave illuminated during each radar sample. When we average the samples of the

James C. West; Richard K. Moore; Julian C. Holtzman; S. P. Gogineni

1989-01-01

71

Partial treatment of wind turbine blades with radar absorbing materials (RAM) for RCS reduction  

Microsoft Academic Search

The application of radar absorbing materials (RAM) in order to reduce the interference of wind farms with radar systems is considered as a possible mitigation solution. This paper will address the key challenges when trying to efficiently apply RAM to certain parts of the wind turbine blades to significantly reduce the scattering of radar signals. Modeling of the radar cross-section

Laith Rashid; Anthony Brown

2010-01-01

72

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

73

A new relationship between radar cross-section and ocean surface wind speed using ERSt scatterometer and buoy measurements  

Microsoft Academic Search

The ERS–I spacecraft scatterometer, C-band VV polarization, acquired radar cross-section measurements over the global oceans during 1992 and 1993. We investigate the cross-section dependence on mean wind speed U using collocated buoys within ±25km of the scatterometer cells. These collocated measurements result in over 75000 matches in two diITerent oceanic regions. The buoys measure hourly mean wind speeds from 0·2–10

C. Rufenach

1995-01-01

74

RCS imaging measurement obtained by scanning parallel electromagnetic wave Beam using dielectric lens antenna  

Microsoft Academic Search

RCS (radar cross section) imaging measurement was obtained by (1) scanning parallel electromagnetic wave beam using a dielectric lens antenna, (2) integrating the same phase signal by comparing the returning signals only relating to the reference signal, and (3) calculating RCS by comparing with a standard target. Using this imaging method, RCS measurements of an airplane with a 1.5 m

H. Suzuki; K. Saito; H. Yamashita; T. Yoshizawa

2009-01-01

75

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

76

Measurements of the Effect of Rain-induced Sea Surface Roughness on the Satellite Scatterometer Radar Cross Section  

Microsoft Academic Search

Radar measurements of the sea surface, with satellite scatterometers that operate at Ku-band, will be affected by the presence of rain through modification of the sea surface roughness by rain impacts. This is in addition to wind driven roughness, atmospheric reflectivity and attenuation that affect the measured normalized radar cross section (NRCS). Numerous surface-based studies, using ocean platforms and wind-wave

David E. Weissman; Mark A. Bourassa

2007-01-01

77

Alignment and illumination issues in scaled THz RCS measurements  

Microsoft Academic Search

Radar cross section (RCS) measurements are widely employed for the target identification of objects such as aircraft. The RCS of large, complex geometries is usually determined in a well defined, scaled experimental setup. In such a setup, the measuring frequency equates the frequency of interest multiplied by the scaling factor of the model. For high scaling factors, frequencies well above

C. Jansen; N. Krumbholz; R. Geise; T. Probst; O. Peters; A. Enders; M. Koch

2009-01-01

78

Maetningar av Bistatisk Radarmalarea hos en Cylinder. (Measurements of Bistatic Radar Cross-Section of a Cylinder).  

National Technical Information Service (NTIS)

In this report, measurements of bistatic radar cross-section are presented. The measurements have been partly on a metal cylinder and partly on a cylinder equipped with a damping material. The length of the cylinder was 1 m and the diameter 10 cm. The fre...

N. Gustafsson G. Haapalahti M. Herberthson

2003-01-01

79

A model function for the ocean-normalized radar cross section at 14 GHz derived from NSCAT observations  

Microsoft Academic Search

A model for the ocean surface normalized radar cross section Co is derived from 3 months of NASA scatterometer (NSCAT) observations (September 15 to December 18, 1996). The model expresses ao as a function of wind speed, relative wind direction, incidence angle, and polarization. The dependence of Co on wind speed is based on collocated special sensor microwave\\/imager (SSM\\/I) satellite

Frank J. Wentz; Deborah K. Smith

1999-01-01

80

Efficient RCS estimation of 2-dimensional cylinder with random holes  

Microsoft Academic Search

In this paper, we propose an efficient method to estimate the radar cross section (RCS) mean and variance of a 2-D cylinder with random holes. This model has been applied extensively in microwave engineering, e.g., frequency selective surface (FSS). Firstly, we develop a deterministic RCS solver based on nodal Discontinuous Galerkin Finite Element Method (DG-FEM). Then, we quantify the RCS

Meilin Liu; J. S. Hesthaven; Shaobin Liu

2009-01-01

81

Influence of Gaussian Beam on Terahertz Radar Cross Section of a Conducting Sphere  

NASA Astrophysics Data System (ADS)

In RCS estimation, usually a plane wave is assumed; while in real measurements at terahertz frequencies, generally a Gaussian beam or a similar beam source is adopted. In this paper, the RCS of a conducting sphere is discussed under the condition that the incident wave is a Gaussian beam. In the estimation, the influence of 2.52 THz collimated laser beam on RCS is discussed and the RCS changing with scattering angle and some other factors is obtained; at the same time, the comparisons between different incident beams, plane wave and Gaussian beam, are also given. The estimation results show that choosing a beam width of 40 mm is appropriate when the sphere radius is 10 mm and the distance between the sphere and the beam source is 1 m.

Li, Hui-Yu; Li, Qi; Xia, Zhi-Wei; Zhao, Yong-Peng; Chen, De-Ying; Wang, Qi

2013-01-01

82

93 - GHz Radar Cross-Section Measurements of Satellite Elemental Scatterers.  

National Technical Information Service (NTIS)

The RCS of representative spacecraft materials and components was measured at 93 GHz. Measurements of solar cells, thermal blanket material, structural components, and sensors are included. These measurements indicate the highly specular nature of scatter...

R. B. Dybdal H. E. King

1975-01-01

83

Temperature control of radar cross-section using electrically small high Tc superconducting antenna elements for stealth applications  

NASA Astrophysics Data System (ADS)

A technique to reduce unwanted scattering by antennas which exploits the inefficiency of high-temperature superconductors above Tc is demonstrated. Electrically small dipole and loop antennas made of superconductors are modeled above and below Tc to predict their scattering efficiencies, and it is shown that a significant transition in radar cross-section occurs which justifies the use of superconductors over copper in stealth applications.

Cook, G. G.; Khamas, S. K.

1993-08-01

84

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

85

The modulation of the radar cross section of the ocean surface by an azimuthally traveling long gravity wave  

NASA Astrophysics Data System (ADS)

A new technique is used to calculate the modulation of the radar cross section of the ocean surface by a long gravity wave having a single narrow-band spectral peak. Spectral analysis of the measured wave height time series is used to determine the position on the dominant wave illuminated during each radar sample. When we average the samples of the signal power received from the same phase position (but during different cycles) on the long wave, the phase-interference (Rayleigh) fading is greatly reduced. The result is a measurement of the average radar cross section of the ocean surface as a function of the position on the long wave. The technique was applied to experimental runs where the radar beam was parallel to the crest of the dominant wave (cross-wave look direction). Significant modulation was observed at both C and X bands, although there was no tilt modulation. A scenario where hydrodynamic and aerodynamic effects give rise to the modulation is discussed. "Sea spikes" occurred primarily near the front face of the long wave, with some also appearing immediately after the crest has passed, supporting the theory that they are often associated with the breaking of ripple waves riding near the top of the long wave.

West, James C.; Moore, Richard K.; Holtzman, Julian C.; Gogineni, S. P.

1989-11-01

86

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

87

Imaging a BQM-74E Target Drone Using Coherent Radar Cross Section Measurements  

Microsoft Academic Search

ince the early 1980s and the advent of the modern computer, digital radar imaging has developed into a mature field. In this article, the specific problem of imaging a rotating target with a stationary radar is reviewed and built upon. The relative motion between the rotating target and the stationary radar can be used to create a circular synthetic aperture

Allen J. Bric

1997-01-01

88

Impact of the divergence factor on accurate RCS calculation using shooting and bouncing rays  

Microsoft Academic Search

The shooting and bouncing rays (SBR) method is a highly powerful technique for radar cross section (RCS) prediction of arbitrarily shaped targets. For the non-flat structures, the divergence factor (DF) plays an important role in accuracate RCS calculation. In practice, triangular surface mesh is widely used in computer aided design (CAD) representation for complex objects. Thus, the DF in SBR

Wei Gao; Miao Sui; Xiaojian Xu

2011-01-01

89

RCS Predictions From a Method of Moments and a Finite-Element Code for Several Targets.  

National Technical Information Service (NTIS)

This report presents results of radar cross section (RCS) calculations for several interesting targets using a method-of-moments code and a finite-element code. A physical optics code does not handle the mechanisms that contribute to the RCS for the targe...

K. Ferreira N. Hirth R. B. Bossoli W. A. Spurgeon

2010-01-01

90

Measurements and Calculations of the Millimeter Wavelength RCS of a Top Hat and Bruderhedrals.  

National Technical Information Service (NTIS)

Polarimetric radar cross sections (RCSs) were measured for a large top hat and three large Bruderhedrals at 35 and 93 GHz. The overall spread in the measured RCSs was 2 dB. It was found that the absolute RCS, as well as the dependence of the RCS on elevat...

J. D. Silverstein R. Bender

1997-01-01

91

RCS and radar propagation near offshore wind farms  

Microsoft Academic Search

The wind farm impact on marine radars has not been widely reported. Some past publications have touched on the subject but there has been no accurate model in place to readily examine the effects of different farm geometries, tower shapes and turbine sizes. This paper discusses the radar propagation modeling near offshore wind farms including the methods used to model

Laith S Rashid; Anthony K Brown

2007-01-01

92

Radar cross section of trihedral corner reflectors using PO and MEC  

Microsoft Academic Search

Physical optics (po) and the method of equivalent currents (mec) are used for the formulation and calculation of the backscatter\\u000a cross section of both the triangular and square trihedral corner reflectors. Scattering from a trihedral corner reflector\\u000a is dominated by single, double, and triple reflections by the interior walls. A physical optics integration is performed on\\u000a the entire surface of

Anastasis C. Polycarpou; Constantine A. Balanis; Craig R. Birtcher

1995-01-01

93

A full wave study of radar cross sections of rough terrain  

NASA Astrophysics Data System (ADS)

Full wave solutions are derived for the like and cross polarized electromagnetic diffuse single scattered fields from two dimensional irregular stratified media. Scattering upon reflection and transmission across random rough surfaces is considered. The surface is characterized by its joint probability density function for the heights and slopes at two points. The full wave expressions involve the height/slope correlations. The full wave results are compared with the small perturbation physical/geometrical, numerical (based on Monte Carlo simulations) and experimental results. Full wave solutions for the double scatter fields and cross sections are also derived for rough surfaces that exhibit enhanced backscatter. The solutions are expressed as an interaction integral between two single scatter cross sections associated with quasi parallel and quasi antiparallel paths. The dependence of the angular width and level of the enhanced backscatter cross section on the mean square height and slope and on the mean width of a typical depression on the rough surface is determined. The results are compared with numerical and experimental data.

Bahar, Ezekiel

1994-08-01

94

Global and high resolution radar cross section measurements and two-dimensional microwave images of a scaled aircraft model from the type Airbus A 310  

Microsoft Academic Search

The results from radar cross section high resolution measurements of a metallized scaled model of a usual airliner of the Airbus A310 type are presented. The measurements were performed for line polarization states by using a coherent short pulse radar at a frequency of 12.5 GHz. Two dimensional microwave images were generated for varied aspect angles by using inverse synthetic

Karl-Heinz Bethke

1991-01-01

95

Radar observables  

NASA Astrophysics Data System (ADS)

A comprehensive account is given of missile design considerations relevant to the prediction, control, and measurement of airframe radar cross sections (RCSs), with a view to the minimization of missile observability. RCS reduction may proceed through airframe shaping to deflect incident radar emissions, as well as through the use of radar-absorbing surface materials and the devision of active radar signal-cancellation methods; some combination of these is often required, due to the deficiencies of any one method. The interaction of all RCS-reduction methods with airframe aerodynamic-design criteria are stressed.

Knott, Eugene F.

96

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

97

The Absolute Scattering Cross-Section of Polar Mesospheric Summer Echoes at VHF and UHF radar frequencies  

NASA Astrophysics Data System (ADS)

Simultaneous and collocated measurements of Polar Mesospheric Summer Echoes (PMSE) with the EISCAT VHF (224 MHz) and the UHF (930 MHz) radars and ionosonde measurements of electron number density, have allowed to make accurate calculations of the absolute cross-section of PMSE. The values of the cross-sections per unit volume obtained are in the range of a few times 10-15--10-14 m-1 for the VHF measurements and a few times 10-18--10-17 m-1 for the UHF measurements, namely the VHF echoes are typically three orders of magnitude stronger than the UHF echoes. These results are at variance with proposed theories of PMSE. In particular, the theory based on neutral air turbulence with an extended convective-diffusive subrange due to charged dust particles as the driver of the electron inhomogeneities, predicts that the strength of PMSE at the VHF frequency should be about 70 times stronger than the strength of PMSE at the UHF frequency. Thus, we suggest that PMSE still remains largely unaccounted for by any theory.

La Hoz, C.; Havnes, O.; Rietveld, M.; Næsheim, L.

2005-12-01

98

Anechoic chambers for EMC, APM and RCS measurements  

Microsoft Academic Search

Summary form only given. This tutorial includes a brief introduction to anechoic chambers and absorber technology. It shows a typical, basic approach to anechoic chamber design for different applications from electromagnetic compatibility (EMC) and radar cross section (RCS) measurements to antenna pattern measurements (APM).

V. Rodriguez

2010-01-01

99

DSI3D-RCS test case manual.  

National Technical Information Service (NTIS)

The DSI3D-RCS code is designed to numerically evaluate radar cross sections on complex objects by solving Maxwell's curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers...

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

1995-01-01

100

An improved composite surface model for the radar backscattering cross section of the ocean surface 1. Theory of the model and optimization\\/validation by scatterometer data  

Microsoft Academic Search

An improved composite surface model for the calculation of the normalized radar backscattering cross section (NRCS) of the ocean surface at moderate incidence angles is presented. The model is based on Bragg scattering theory. A Taylor expansion of the NRCS in the two-dimensional surface slope yields nonzero second-order terms which represent a first approximation for the effect of the geometric

Roland Romeiser; Werner Alpers; Volkmar Wismann

1997-01-01

101

APPLICATION OF DOUBLE ZERO METAMATERIALS AS RADAR ABSORBING MATERIALS FOR THE RE DUCTION OF RADAR CROSS SECTION  

Microsoft Academic Search

We introduce and investigate the applications of double zero (DZR) metamaterials (having the real parts of permittivity and permeability equal to zero) as radar absorbing materials (RAMs). We consider a perfectly electric conductor (PEC) plate covered by several layers of DZR metamaterial coatings under an oblique plane wave incidence of arbitrary polarization. Several analytical formulas are derived for the realization

H. Oraizi; A. Abdolali; N. Vaseghi

2010-01-01

102

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

103

Time-varying RCS modeling algorithms  

NASA Astrophysics Data System (ADS)

Teledyne Brown Engineering (TBE) has developed high-fidelity exoatmospheric time-varying radar cross section (RCS) models for use in the Warning Information Correlation (WIC) threat development effort. These models have been developed for the objects of six USSR ICBM and SIBM weapon systems. This report describes the five TBE developed time-varying RCS modeling algorithms that were utilized for these models. Part of the validation of these models consisted of comparisons of selected discrimination signatures calculated from model and recorded data. The definition of these signatures is also presented.

Gruner, W. J.

1981-12-01

104

Cross-section of coherent radar scattering from nonthermal plasma density fluctuations in the mid-latitude ionosphere  

NASA Astrophysics Data System (ADS)

Methods based on coherent radar scattering yield very important information about nonthermal plasma density fluctuations in the lower ionosphere at different latitudes In particular the information is helpful for better understanding of the nature of the fluctuations A noticeable role in producing the fluctuations below the homopause level belongs to neutral air turbulence The turbulence is especially important in the case when development of plasma instabilities is difficult A convenient value that describes the process of radio wave coherent scattering from plasma density fluctuations is an effective cross-section sigma An analytic formula of sigma for the plasma fluctuations induced by the neutral turbulence is presented in the report The formula is obtained with the use of the 3D fluctuation spectrum predicted by a quasi-neutral fluid theory of the fluctuations Using the formula we estimated values of sigma for a possible radar backscatter experiment in the case of plasma fluctuations near the 100-km altitude in the daytime and nighttime mid-latitude ionosphere the magnetic dip angle of 45° The local values for the length-scale of the vertical plasma-density gradient L N of about 7 km and the average plasma density N e of 2 times10 10 mathrm m -3 plasma frequency f p approx 1 27 MHz were chosen for the daytime ionosphere and L N approx 3 km N e approx 2 times10 9 mathrm m -3 f p approx 0 4 MHz at night The ratio of the ion gyro-frequency to the ion-neutral collision frequency of about 0 035 and the

Kyzyurov, Yu.

105

Phase-hologram-based compact RCS test range at 310 GHz for scale models  

Microsoft Academic Search

A compact radar cross section (RCS) test range based on a phase hologram has been developed for scale-model measurements. The phase hologram converts the feed-horn radiation to a plane wave needed for RCS determination. The measurements are performed at 310 GHz using continuous-wave operation. A monostatic configuration is realized using a dielectric slab as a directional coupler. The main advantage

Anne Lönnqvist; Juha Mallat; Antti V. Räisänen

2006-01-01

106

On the interaction between the DUT’s radar cross section and the reactive effect of TEM cells  

Microsoft Academic Search

A simple novel approach for an efficient investigation of the interactions between the DUT and the cell is provided. Closed-form expressions for the reflection coefficient, the relative deviation in field and the relative error in induced current caused by the reactive effect of the cell are derived. Each of these expressions encompasses both the mutual influence of the DUT’s RCS

David Pouhe; Gerhard Monich

2007-01-01

107

Modeling with NURBS surfaces used for RCS computation of electrically large objects  

Microsoft Academic Search

The non-uniform rational B-spline (NURBS) model is constructed based on the data points on the surface of a target, and the B-Spline basis functions are analyzed. The radar cross section (RCS) is calculated with the physical optics (PO) and LUDWIG integral method based on NURBS models, which verifies the validity of the modeling method mentioned in this paper.

Zhao Yan; Xu Le; Shi Xiaowei

2007-01-01

108

RCS calculation of complex targets shielded with plasma based on visual GRECO method  

Microsoft Academic Search

Based on the assumption that plasma medium is cold, unmagnetized, collisional and inhomogeneous, a radar cross section (RCS) calculation model for complex targets shielded with plasma is presented. In high frequency region, the plasma that defilading a target can be treated as layered media. In each layer, the plasma is equivalent to a uniform dielectric. Physics optics (PO), ray-tracing method

Wang Gu; Yuan Lei; Wang Taosheng; Fang Ning; Miao Jungang; Wang Baofa

2009-01-01

109

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

110

Construction of Training Database Based on High Frequency RCS Prediction Methods For ATR  

Microsoft Academic Search

Due to the difficulty of creating training databases using all real enemy targets, it is necessary to derive them using computer simulations. In this paper, we apply three high frequency radar cross section (RCS) methods to create a training database for automatic target recognition (ATR) using 1-D range profiles. These methods are: physical optics (PO), physical theory of diffraction (PTD)

S. H. Park; K. K. Park; J. H. Jung; H. T. Kim; K. T. Kim

2008-01-01

111

GPU-Based Shooting and Bouncing Ray Method for Fast RCS Prediction  

Microsoft Academic Search

The shooting and bouncing ray (SBR) method is highly effective in the radar cross section (RCS) prediction. For electrically large and complex targets, computing scattered fields is still time-consuming in many applications like range profile and ISAR simulation. In this paper, we propose a GPU-based SBR that is fully implemented on the graphics processing unit (GPU). Based on the stackless

Yubo Tao; Hai Lin; Hujun Bao

2010-01-01

112

Hybrid FEM\\/Floquet Modes\\/PO Technique for Multi-Incidence RCS Prediction of Array Antennas  

Microsoft Academic Search

An original method is proposed which associates rigorous 3D finite element methods (FEM) with Floquet modes through FACTOPO multidomain formalism for computing the radar cross section (RCS) of large array antennas. The most original aspect of the method is the fact that the source unit cell is characterized by a generalized scattering matrix (GSM) which does not depend on the

Renaud Chiniard; André Barka; Olivier Pascal

2008-01-01

113

Compact ranges in antenna and RCS measurements  

NASA Astrophysics Data System (ADS)

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 allow for indoor measurements under far field conditions in real time without any calculation effort. Several types of compact ranges are described and compared discussing their relevant advantages with regard to RCS and antenna measurements. In parallel to measuring systems sophisticated computer models were developed with such a high level of accuracy that it is questionable whether experiments give better results than theory. Tests performed on simple structures show the correlation between experimental results and theoretical ones derived on the basis of GTD computer codes.

Audone, B.

1989-09-01

114

Spectral characteristics and scatter cross-section of low latitude mesospheric echoes measured by the Indian MST radar at Gadanki  

NASA Astrophysics Data System (ADS)

In November 2008 and in March and April 2009 the Indian MST radar (53 MHz) at Gadanki was operated during the daytime in a special experiment, with 600 m altitude resolution, for understanding the characteristics of low-latitude mesospheric echoes (LLME). The data of three days when the echoes were strongest have been analysed in terms of spectral widths and radar volume reflectivities. Spectral widths of LLME show some decrease with altitude, with median values of 4-6 m s-1 at 69-72 km and of 2-4 m s-1 at 73-78 km. This corresponds to 20-200 mW kg-1 turbulent energy dissipation rates. It has been shown that stronger echoes have broader spectra consistent with a turbulent scattering mechanism. For the first time, the volume reflectivities for the strong LLME for Gadanki have also been calculated. They are in the range of 10-17-10-15 m-1, so LLME at Gadanki are somewhat stronger than those reported so far from Jicamarca, Peru (Lehmacher et al., 2009).

Belova, E.; Kirkwood, S.; Narayana Rao, T.; Satheesh Kumar, S.; Sergienko, T.

2012-06-01

115

Tracking and classification using aspect-dependent RCS and kinematic data  

NASA Astrophysics Data System (ADS)

The joint target tracking and classification using target-to-sensor aspect-dependent Radar Cross Section (RCS) and kinematic data for multistatic sonar network is presented in this paper. The scattered signals measured from different orientations of a target may vary due to aspect-dependant RCS. A complex target may contain several dozen significant scattering centers and dozens of other less significant scatterers. Because of this multiplicity of scatterers, the net RCS pattern exhibits high variation with aspect angle. Thus, radar cross sections from multiple aspects of a target, which are obtained via multiple sensors, will help in accurately determining the target class. By modeling the deterministic relationship that exits between RCS and target aspect, both the target class information and the target orientation can be estimated. Kinematic data are also very helpful in determining the target class as it describes the target motion pattern and its orientation. The proposed algorithm exploits the inter-dependency of target state and the target class using aspect-dependent RCS and kinematic information in order to improve both the state estimates and classification of each target. The simulation studies demonstrate the merits of the proposed joint target tracking and classification algorithm based on aspect-dependant RCS and kinematic information.

Sutharsan, S.; Tharmarasa, R.; Lang, T.; Kirubarajan, T.

2008-05-01

116

Multi-frequency and multi-polarization measurements of water surface radar cross section and brightness temperature angular dependences  

NASA Astrophysics Data System (ADS)

In this paper the results of simultaneous and spatially coincident, multi-frequency, polarimetric, spatio-temporally collocated measurements of waved pool water surface microwave reflective (radar backscattering coefficient) and emissive (brightness temperature) characteristics angular dependences at 5.6GHz, 15GHz and 37GHz are presented. Angular measurements were carried out for various water surface roughness parameters at clear air, cloudy and rain conditions. For these measurements C-, Ku and Ka-band, polarimetric, combined scatterometric-radiometric systems were used, set jointly on a mobile buggy moving along the measuring platform. Structures, operational features and the main technical characteristics of the utilized systems are presented too. The paper has an aim as well to attract attention of interested researchers and to invite them to perform their own or joint researches using available devices and facilities.

Arakelyan, Artashes K.; Hambaryan, Astghik K.; Arakelyan, Arsen A.; Grigoryan, Melanya L.

2011-10-01

117

On the statistical analysis of the radar signature of the MQM-34D  

Microsoft Academic Search

The report contains the results of an analysis of the radar signature of the MQM-34D target drone for seven aspect angle regions for a horizontally polarized measurements system. The radar cross section (RCS) and glint are compared with classical models. The RCS falls off about 4.7 dB for a 30 degrees bistatic angle for the aspect regions less than 30

J. W. Wright

1975-01-01

118

Analysis of impacts of various RAM on RCS of 3-D complex targets using the FEM-FMA [radar absorbing materials  

Microsoft Academic Search

The hybrid vector finite element method and fast multipole algorithm (FEM-FMA) are used to calculate the RCS of 3D complex targets coated with various radar absorbing materials (RAM). For a cone as an example, This work analyzes the impact of four canonical RAM coatings, including lossy isotropic, positive uniaxial anisotropic, negative uniaxial anisotropic and nanometer absorbing materials on the electromagnetic

Wang Pai; Zhou Lezhu; Tan Yanhua; Xia Mingyao

2004-01-01

119

Bistatic synthetic aperture radar with non-cooperative LEOS based transmitter  

Microsoft Academic Search

The authors consider Low Earth Orbited Satellite (LEOS) systems for personal communications. Their rather high power spectral density near the Earth surface could be used for aircraft detection. Bistatic radars that utilize communication signal transmitting from LEOS could operate in a passive mode. Moreover, the targets will be characterized by their bistatic radar cross-section (RCS) that could be 20 to

C. Mikhail; K. Kurt; N. David

2000-01-01

120

A particle filtering approach to FM-band passive radar tracking and automatic target recognition  

Microsoft Academic Search

We present two stochastic filters for an FM-band passive air surveillance radar. The first system uses an extended Kalman filter and delay-Doppler measurements to track targets. The second system uses a particle filter to simultaneously track and classify targets. Automatic target recognition is made possible by the inclusion of radar cross section (RCS) in the measurement vector. The extended Kalman

Shawn Herman; Pierre Moulin

2002-01-01

121

On the Statistical Analysis of the Radar Signature of the MQM-34D.  

National Technical Information Service (NTIS)

The report contains the results of an analysis of the radar signature of the MQM-34D target drone for seven aspect angle regions for a horizontally polarized measurements system. The radar cross section (RCS) and glint are compared with classical models. ...

J. W. Wright

1975-01-01

122

Automatic recognition of ground radar targets based on target RCS and short time spectrum variance  

Microsoft Academic Search

This paper presents a novel feature vector to be used with a robust automatic target recognition (ATR) classifier designed for a ground surveillance radar. A three element feature vector has been used where features are based on radar audio signal of 100 milliseconds duration. The short feature length allows fast real-time implementation of the classifier. Classification is done using a

S. Liaqat; S. A. Khan; M. B. Ihsan; S. Z. Asghar; A. Ejaz; A. I. Bhatti

2011-01-01

123

Implementation of an active noise suppression system in C-band indoor RCS measurements  

Microsoft Academic Search

The present article shows the results of ongoing works at AMR\\/IAE\\/CTA in the configuration of an experimental setting necessary to determine the error sources in radar cross section (RCS) measurements and hence minimize them by means of a system developed to measure targets in C- Band (6.0 GHz), in a closed environment, using an anechoic chamber. Microwave circuit techniques were

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

2007-01-01

124

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

125

In Search of the Statistical Properties of High-Resolution Polarimetric SAR Data for the Measurements of Forest Biomass Beyond the RCS Saturation Limits  

Microsoft Academic Search

The purpose of this letter is to present the results on the study of searching effective parameters that describe the relation between high-resolution synthetic aperture radar (SAR) images and forest parameters. The study is based on the non-Gaussian texture analysis of the polarimetric airborne Pi-SAR data over coniferous forests in Hokkaido, Japan. The radar cross section (RCS) in terms of

Haipeng Wang; Kazuo Ouchi; Manabu Watanabe; Masanobu Shimada; Takeo Tadono; Ake Rosenqvist; Shakil Ahmad Romshoo; Masayuki Matsuoka; Toshifumi Moriyama; Seiho Uratsuka

2006-01-01

126

Insensitive Environment Calibration Procedure for an Instrumental Radar  

Microsoft Academic Search

In this paper, we present a calibration procedure for radar cross section (RCS) measurement systems that is insensitive to environmental perturbations. This procedure has been used in several measurement campaigns to calibrate the measurement system of the Spanish Navy called LIBRA. The proposed method not only allows us to discard environment corrupted measurements but also to make use of them

I. García-Tuñón; J. L. Rodríguez; F. Obelleiro; M. G. Araújo; J. M. Taboada

2010-01-01

127

Nuclear cross sections  

Microsoft Academic Search

Nuclear cross sections, sigmaij,i=pi+\\/-, K+, K-, p, p, A; j=p, A have been derived for all energies. A new expression for the average charged particle multiplicity together with new empirical formulas for elastic and inelastic pp cross sections have been derived and used to determine the nuclear cross sections. Extrapolations to high and superhigh energies are given. For instance, at

Arne Liland

1993-01-01

128

Validation of a chi2 model of HRR target RCS variability and verification of the resulting ATR performance model  

NASA Astrophysics Data System (ADS)

A (chi) 2 model for radar cross section (RCS) variability of High Range Resolution (HRR) measurements is validated using compact range data from the U.S. Army National Ground Intelligence Center (NGIC). It is shown that targets can be represented by a mean template and by a variance template, or in this case, an effective number of degrees-of-freedom for the (chi) 2-distribution. The analysis also includes comparison of the measured tails of the RCS distribution to that predicated by the (chi) 2-distribution. The likelihood classifier is obtained, and a Monte Carlo performance model is developed to validate the statistical model at the level of ATR performance.

Holt, Craig R.; Attili, Joseph B.; Schmidt, Steven L.

2001-10-01

129

Flashlight radar: A three-dimensional imaging radar  

NASA Astrophysics Data System (ADS)

In support of several programs at Lincoln Laboratory, a small focused-beam polarimetric, millimeter-wave radar scatterometer (an instrument for measuring radar cross section) has been developed. An overview of the design of this Flashlight Radar is presented. Theoretical and empirical studies of antenna performance are discussed. The backscatter theory relating to the characteristics of the Flashlight Radar as a scatterometer is presented, and experimental RCS measurements are compared with theoretical predictions. The data processing steps (polarimetric calibration and compensation, signal processing, and image formation) are described. We show the results of two representative experiments using the Flashlight Radar. The first is a measurement of dihedral and trihedral reflectors with and without radar camouflage. The second is a faster scan of a truck tire, highlighting the radar's fine resolution and its ability to collect three-dimensional data.

Blejer, Dennis J.; Ferranti, Richard L.; Barnes, Richard M.; Irving, William W.; Verbout, Shawn M.

1989-08-01

130

Solar fusion cross sections  

Microsoft Academic Search

We review and analyze the available information on the nuclear-fusion cross sections that are most important for solar energy generation and solar neutrino production. We provide best values for the low-energy cross-section factors and, wherever possible, estimates of the uncertainties. We also describe the most important experiments and calculations that are required in order to improve our knowledge of solar

Eric G. Adelberger; Sam M. Austin; John N. Bahcall; A. B. Balantekin; Gilles Bogaert; Lowell S. Brown; Lothar Buchmann; F. Edward Cecil; Arthur E. Champagne; Ludwig de Braeckeleer; Charles A. Duba; Steven R. Elliott; Stuart J. Freedman; Moshe Gai; G. Goldring; Christopher R. Gould; Andrei Gruzinov; Wick C. Haxton; Karsten M. Heeger; Ernest Henley; Calvin W. Johnson; Marc Kamionkowski; Ralph W. Kavanagh; Steven E. Koonin; Kuniharu Kubodera; Karlheinz Langanke; Tohru Motobayashi; Vijay Pandharipande; Peter Parker; R. G. Robertson; Claus Rolfs; R. F. Sawyer; N. Shaviv; T. D. Shoppa; K. A. Snover; Erik Swanson; Robert E. Tribble; Sylvaine Turck-Chièze; John F. Wilkerson

1998-01-01

131

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

Microsoft Academic Search

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

Ezekiel Bahar; Bom Son Lee

1994-01-01

132

Globale und Hochaufgeloeste Radarrueckstrahlquerschnitts-Messungen und Zweidimensionale Mikrowellenabbildungen von Einem Skalierten und Flugzeugmodell Vom Typ Airbuss a 310 (Global and High Resolution Radar Cross Section Measurements and Two-Dimensional Microwave Images of a Scaled Aircraft Model from the Type Airbus A310).  

National Technical Information Service (NTIS)

The results from radar cross section high resolution measurements of a metallized scaled model of a usual airliner of the Airbus A310 type are presented. The measurements were performed for line polarization states by using a coherent short pulse radar at...

K. Bethke

1991-01-01

133

DSI3D-RCS: Theory manual  

SciTech Connect

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

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

1995-03-16

134

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.

Pinter, Nicholas

135

Comparison between EISCAT UHF and VHF backscattering cross section  

Microsoft Academic Search

We present a comparison between the backscattering cross sections at 224 and 933 MHz measured with European Incoherent Scatter (EISCAT) radars during the passage of a discrete arc. It shows a difference of 2 orders of magnitude which cannot simply be explained by normal thermal ionospheric density fluctuations. We claim that the observed difference in the scattering cross sections is

B. Cabrit; H. Opgenoorth; W. Kofman

1996-01-01

136

Monostatic Reflectivity and Transmittance of Radar Absorbing Materials at 650 GHz  

Microsoft Academic Search

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

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

2008-01-01

137

Ground-to-air measurement radar (GTAMS) for aircraft signature measurements  

Microsoft Academic Search

An advanced portable instrumentation radar system for radar cross section(RCS) measurements of airborne targets is described. This system operates in the 7-11-GHz region, has a maximum continuous bandwidth of 4 GHz, utilizes programmable waveforms, and is operable in the stepped frequency, fixed frequency or the burst grab mode with pulse repetition frequency (PRF) to 500 kHz. The transmitter has 200

A. Jain; I. Patel

1992-01-01

138

Automated target recognition using passive radar and coordinated flight models  

NASA Astrophysics Data System (ADS)

Rather than emitting pulses, passive radar systems rely on illuminators of opportunity, such as TV and FM radio, to illuminate potential targets. These systems are particularly attractive since they allow receivers to operate without emitting energy, rendering them covert. Many existing passive radar systems estimate the locations and velocities of targets. This paper focuses on adding an automatic target recognition (ATR) component to such systems. Our approach to ATR compares the Radar Cross Section (RCS) of targets detected by a passive radar system to the simulated RCS of known targets. To make the comparison as accurate as possible, the received signal model accounts for aircraft position and orientation, propagation losses, and antenna gain patterns. The estimated positions become inputs for an algorithm that uses a coordinated flight model to compute probable aircraft orientation angles. The Fast Illinois Solver Code (FISC) simulates the RCS of several potential target classes as they execute the estimated maneuvers. The RCS is then scaled by the Advanced Refractive Effects Prediction System (AREPS) code to account for propagation losses that occur as functions of altitude and range. The Numerical Electromagnetic Code (NEC2) computes the antenna gain pattern, so that the RCS can be further scaled. The Rician model compares the RCS of the illuminated aircraft with those of the potential targets. This comparison results in target identification.

Ehrman, Lisa M.; Lanterman, Aaron D.

2003-09-01

139

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

140

Difference between interaction cross sections and reaction cross sections  

Microsoft Academic Search

We study the validity of the substitution of interaction cross sections for total reaction cross sections for a nucleus incident on a target nucleus at relativistic energies. We show that, for incident stable nuclei, the predicted difference between interaction and total reaction cross sections is large enough to probe the nuclear structure, particularly in a mass region of less than

Akihisa Kohama; Kei Iida; Kazuhiro Oyamatsu

2008-01-01

141

Photodetachment cross section of Cu⁻  

Microsoft Academic Search

We report the first ab initio calculation of the photodetachment cross section of the bound Cu⁻ ion. The calculated cross section exhibits two shape resonances, the larger of which should be accessible experimentally. The magnitude of the cross section is substantial ((6.8--7.1) x 10⁻¹⁷ cm²) at wavelengths associated with the copper-vapor laser.

K. F. Scheibner; A. U. Hazi

1988-01-01

142

NUCLEAR CROSS SECTION STATUS REPORT  

Microsoft Academic Search

The current status of cross-section knowledge is discussed, and ; experiments and calculations for increasing this knowledge are described. A ; bibliography of available cross-section data is given, and recommendations for a ; program designed to provide more cross-section information are made. (auth)

R. W. Deutsch; N. C. Francis; B. E. Simmons; P. F. Zweifel

1956-01-01

143

Semicylindrical Radar Absorbing Structures using Fiber-reinforced Composites and Conducting Polymers in the X-band  

Microsoft Academic Search

This paper presents a low observable structure with curved surfaces made by fiber-reinforced composites, conducting polymers and shows the possibility of developing stealth platforms for military applications. We propose radar absorbing structures (RAS) based on a circuit analog absorber in order to reduce the radar cross-section (RCS) of an object with curved surfaces. First, semi-cylindrical RAS with a periodic square

Hong-Kyu Jang; Jae-Hwan Shin; Chun-Gon Kim; Sang-Hun Shin; Jin-Bong Kim

2011-01-01

144

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

145

The total charm cross section  

SciTech Connect

We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

Vogt, R

2007-09-14

146

International Evaluation of Neutron Cross Section Standards  

Microsoft Academic Search

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

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

2009-01-01

147

ATR discrimination-SNR for HRR assuming chi2 model of RCS variability  

NASA Astrophysics Data System (ADS)

A discrimination SNR for predicting classification performance is developed as an analogy to the RADAR equation that is used to predict detection performance. It assumes a statistical model for the target radar cross-section (RCS) and that the resulting likelihood classifier is employed. The relationship between the probability of classification errors and the dB value of the discrimination SNR is obtained. A specific form for the likelihood classifier and the discrimination SNR is developed assuming that the variability of the target RCS is described by a (chi) 2 - distribution. The form of this (chi) 2 - based classifier is novel and significantly different from the more common Gaussian based mean-square-error classifier. It is shown that the discrimination SNR has an intuitive interpretation in terms of the number of radar samples, the average contrast between targets and the contrast-noise. The use of this tool is illustrated using compact range High Range Resolution (HRR) Doppler measurements from the U.S. Army National Ground Intelligence Center (NGIC). The sensitivity of ATR performance to radar parameters is quantified using the discrimination SNR with gains measured in meaningful dB units.

Holt, Craig R.; Schmidt, Steven L.; Attili, Joseph B.

2001-10-01

148

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

149

Neutron cross sections: Volume 2, Neutron cross section curves  

Microsoft Academic Search

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

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

1988-01-01

150

Reduced Radar Cross Section Exhaust Nozzle Assembly.  

National Technical Information Service (NTIS)

An exhaust nozzle assembly includes a plurality of interfitting flap assemblies that are moveable between a maximum area ratio and a minimum area ratio. Each of the pluralities of flap assemblies includes a slot and a wing. The wing fits within an adjacen...

J. Allore J. A. Arbona M. Harris S. Laporte

2005-01-01

151

Radar cross section of complex objects  

Microsoft Academic Search

The present issue of the Annals of Telecommunications, initiated by J. M. L. Bernard, G. Pelosi, and P. Ya. Ufimtsev, is devoted to the presentation of several recently obtained results in the field of electromagnetic wave diffraction by complex objects. This now well recognized scientific field has strongly expanded during the last decades most notably thanks to the efforts of

Alain F. Lanusse; Pierre Fuerxer

1995-01-01

152

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

153

DSI3D-RCS test case manual  

SciTech Connect

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

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

1995-08-01

154

Radar image processing for the AFIT anechoic chamber  

NASA Astrophysics Data System (ADS)

The purpose of this study was to begin development of an Inverse Synthetic Aperature Radar imaging capability for the AFIT anechoic chamber. This began with an evaluation of the capabilities and limitations of the existing radar system and the chamber itself for this application. Then, after deciding on the image processing approach, software had to be written to collect the data necessary for image processing. This constituted the majority of this study, and resulted in a versatile, user-friendly program that automates the process of collecting data for high-resolution radar images. The program checks that the data to be collected will lead to a valid radar cross-section (RCS) image, but will allow data collection for general radar images. Finally, the image processing software was begun. This made use of commercially available software packages called PC-MATLAB and PRO-MATLAB. Further work is needed on the image processing software to generate calibrated images, and to perform focusing.

Sanders, Brian K.

1990-12-01

155

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

156

A Schematic Theory of Nuclear Cross Sections  

Microsoft Academic Search

In this paper a description of the energy dependence of nuclear cross sections, especially for neutrons, is given in terms of simple assumptions on the properties of the nuclei. The results are supposed to represent average values over individual fluctuations and resonances. The total cross section, the reaction cross section, and the transport cross section are calculated as functions of

H. Feshbach; V. F. Weisskope

1949-01-01

157

Widths of fluctuations in nuclear cross sections  

Microsoft Academic Search

At high energies cross section resonances due to states of compound ; nuclei in nuclear reactions overlap, and the partial reaction cross sections ; fluctuate as a function of energy. Ericson's formuias for the probability ; distribution of a partial cross section sigma are obtained. Additionally, ; relations for the average number of maxima in the cross section per unit

D. M. Brink; R. O. Stephen

1963-01-01

158

Microscopic cross sections: An utopia?  

NASA Astrophysics Data System (ADS)

The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed.

Hilaire, S.; Koning, A. J.; Goriely, S.

2010-10-01

159

An Investigation into the Total Reaction Cross Section and Production Cross Section of Energetic Particles  

Microsoft Academic Search

New calculations for the total reaction cross sections and production cross sections of the energetic particles are carried out via the nuclear transport theory. The experimental total reaction cross sections can be reproduced. In addition, the effects of some ingredients on the total reaction cross sections can be easily analyzed. It is found that the total reaction cross sections are

Yugang Ma; Wenqing Shen; Jun Feng; Yuqiang Ma

1993-01-01

160

3D characterization of radar targets by means of ISAR/SAR near field imaging techniques  

NASA Astrophysics Data System (ADS)

Inverse synthetic aperture radar (ISAR) imaging techniques based on indoor near field backscattering measurements turns out to be a powerful tool for diagnostic purposes in radar cross-section (RCS) reduction and for deriving RCS target models, viable for radar systems operating at larger distances, e.g. under far field conditions. This paper presents an advanced 3-D imaging approach, where in addition to the turntable rotation the antenna is moved along a linear path chosen in accordance with the geometry of the target and the aspect angle of interest. For reconstructing the reflectivity distribution a configuration-specific grid of spatial sampling points is employed which reduces the complexity of determining correct values for the scattering amplitudes. The reflectivity distribution reproduces the backscattering seen from an antenna moved along a finite surface (synthetic 2-D-aperture) in the scattering near field of the target, but is to be used to model backscattering for antennas at larger distances, e.g. in the far field. Therefore, the feasibility of this approach is discussed with respect to different applications, i.e. for the diagnostic of RCS reduction and for deterministic or statistical RCS models. Results obtained for a car as X-band radar target are presented in order to verify the features of the imaging system.

John, Marc-Andre; Aulenbacher, Uwe; Inaebnit, Christian

2007-04-01

161

Neutron Cross Sections of Americium241  

Microsoft Academic Search

Neutron cross sections of Am are evaluated in the energy region of 1 keV–15MeV, by using optical and statistical model calculations. Existing experimental data for this nuclide are very scarce, except for the fission cross section. An empirical formula for the fission cross section is used to reproduce the experimental data. The cross sections on (n, 2n) and (n, 3n)

Sin-iti IGARASI

1977-01-01

162

High-frequency techniques for RCS prediction of plate geometries  

NASA Astrophysics Data System (ADS)

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

163

Controlling radar signature  

SciTech Connect

Low observable technologies for military and tactical aircraft are reviewed including signature-reduction techniques and signal detection/jamming. Among the applications considered are low-signature sensors and the reduction of radar cross section in conjunction with radar-absorbing structures and materials. Technologies for reducing radar cross section are shown to present significant technological challenges, although they afford enhanced aircraft survivability.

Foulke, K.W. (U.S. Navy, Naval Air Warfare Center, China Lake, CA (United States))

1992-08-01

164

Recent fission cross section standards measurements  

SciTech Connect

The /sup 235/U(n,f) reaction is the standard by which most neutron induced fission cross sections are determined. Most of these cross sections are derived from relatively easy ratio measurements to /sup 235/U. However, the more difficult /sup 235/U(n,f) cross section measurements require the use of advanced neutron detectors for the determination of the incident neutron fluence. Examples of recent standard cross section measurements are discussed, various neutron detectors are described, and the status of the /sup 235/U(n,f) cross section standard is assessed. 23 refs., 8 figs., 4 tabs.

Wasson, O.A.

1985-01-01

165

High-Energy Cross Sections. II. Nucleon-Nucleon Cross Section at Cosmic-Ray Energies  

Microsoft Academic Search

Cosmic-ray measurements are capable of yielding reliable results for the cross section of a nucleus for proton or neutron collisions involving a not too small energy transfer. This cross section should therefore be less than, or at most equal to, the true nonelastic cross section (reaction cross section). Results of recent cosmic-ray work are assembled and compared with the reaction

Robert W. Williams

1955-01-01

166

The Meteoroid Input Function and predictions of mid-latitude meteor observations by the MU radar  

NASA Astrophysics Data System (ADS)

The majority of extraterrestrial particles entering Earth's atmosphere originate from the Sporadic Meteoroid Complex (SMC) and are associated with many mesospheric layer phenomena. The Meteoroid Input Function (MIF) is a model that has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. The MIF has been shown to accurately predict the seasonal and diurnal variations of the meteor flux observed by High Power Large Aperture (HPLA) radars at various geographic locations, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR). For this, the model requires the assessment of a potential observational bias of the particular HPLA radar utilized: the minimum detectable radar cross-section (RCS). The RCS sensitivity threshold provides a metric to characterize the radar system's ability to detect particles with a given mass and speed. In this paper, the MIF model was used to predict meteor properties (e.g. the distributions of areal density, speed, and radiant location) observed by the Middle and Upper atmosphere (MU) radar while leveraging the system's interferometric capability to address the model's ability to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. This study demonstrates that the MIF accurately considered the speed and sporadic source distributions for the portion of the meteoroid population observable by the MU radar, and the applicability of the MIF to the MU system increases the confidence of using it as a global model.

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

2013-03-01

167

An algorithm for automatic target recognition using passive radar and an EKF for estimating aircraft orientation  

NASA Astrophysics Data System (ADS)

Rather than emitting pulses, passive radar systems rely on "illuminators of opportunity," such as TV and FM radio, to illuminate potential targets. These systems are attractive since they allow receivers to operate without emitting energy, rendering them covert. Until recently, most of the research regarding passive radar has focused on detecting and tracking targets. This dissertation focuses on extending the capabilities of passive radar systems to include automatic target recognition. The target recognition algorithm described in this dissertation uses the radar cross section (RCS) of potential targets, collected over a short period of time, as the key information for target recognition. To make the simulated RCS as accurate as possible, the received signal model accounts for aircraft position and orientation, propagation losses, and antenna gain patterns. An extended Kalman filter (EKF) estimates the target's orientation (and uncertainty in the estimate) from velocity measurements obtained from the passive radar tracker. Coupling the aircraft orientation and state with the known antenna locations permits computation of the incident and observed azimuth and elevation angles. The Fast Illinois Solver Code (FISC) simulates the RCS of potential target classes as a function of these angles. Thus, the approximated incident and observed angles allow the appropriate RCS to be extracted from a database of FISC results. Using this process, the RCS of each aircraft in the target class is simulated as though each is executing the same maneuver as the target detected by the system. Two additional scaling processes are required to transform the RCS into a power profile (magnitude only) simulating the signal in the receiver. First, the RCS is scaled by the Advanced Refractive Effects Prediction System (AREPS) code to account for propagation losses that occur as functions of altitude and range. Then, the Numerical Electromagnetic Code (NEC2) computes the antenna gain pattern, further scaling the RCS. A Rician likelihood model compares the scaled RCS of the illuminated aircraft with those of the potential targets. To improve the robustness of the result, the algorithm jointly optimizes over feasible orientation profiles and target types via dynamic programming.

Ehrman, Lisa M.

168

[Fast neutron cross section measurements  

SciTech Connect

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

Knoll, G.F.

1992-10-26

169

Vertically stabilized elongated cross-section tokamak  

DOEpatents

This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

Sheffield, George V. (Hopewell, NJ)

1977-01-01

170

Neutron cross sections: Book of curves  

Microsoft Academic Search

Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross

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

1988-01-01

171

A nuclear cross section data handbook  

Microsoft Academic Search

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

H. O. M

1989-01-01

172

Photoacoustic measurement of absolute overtone cross sections  

NASA Astrophysics Data System (ADS)

Using the photoacoustic effect, integrated absorption cross sections for the 5-0 and 6-0 C?H stretching overtones of ethane and ethylene were calibrated against the well-known cross sections for the 4-0 and 5-0 overtones of HD. The results of this calibration procedure agree well with FT-IR measurements by Quack and co-workers. Thus, these absorption cross sections would serve well as secondary reference standards in overtone measurements.

Gutow, J. H.; Davidsson, J.; Zare, R. N.

1991-10-01

173

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

174

Computerized cross section balance and restoration  

Microsoft Academic Search

We describe how to make the necessary measurements and manipulations to balance and restore cross sections using the widely available programs Canvas™, Photoshop™, and Excel™. Data or cross sections are input to Canvas from a flatbed scanner or a video camera, or sections are constructed using program drafting tools. Scanned photos and captured video are significantly improved using Photoshop filters.

Jean-Luc Epard

1996-01-01

175

HAUSER5; Nuclear Reaction Cross Sections.  

National Technical Information Service (NTIS)

HAUSER5 calculates angle-integrated and, if desired, angle-differential reaction cross sections which can include capture and fission channels. Cross sections for discrete particle channels can be calculated, as well as the total for each reaction pair. T...

F. M. Mann

1984-01-01

176

Nuclear Cross Sections at Low Energies  

Microsoft Academic Search

The note is concerned with estimates of the accuracy of the one-term formula for the energy dependence of the reaction cross section for charged particles. The second term in an expansion of the cross section in powers of the energy is worked out for a one-body model. Comparison with data of Sawyer and Phillips on the bombardment of Li and

J. L. Johnson; H. M. Jones

1954-01-01

177

On probability distributions of nuclear cross sections  

Microsoft Academic Search

The nuclear cross section probability distributions in heavy nuclei are ; shown to be of simple form and to yield information on the reaction mechanisms ; and the structure of the scattering amplitude. The form of the probability ; distribution obtained provides a consistency check on the results obtained from ; cross section correlation functions. Scattering amplitudes are considered for

Torleif Eric Oskar Ericson

1963-01-01

178

Nuclear Cross Sections For Fast Reactors  

Microsoft Academic Search

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

S. Yiftah; M. Sieger

1964-01-01

179

Nuclear Cross Sections for 765 Mev Neutrons  

Microsoft Academic Search

Total cross sections have been measured for the elements H, D, Li, C, O, Al, Cu, Sb and Pb and absorption cross sections for C, Al, Cu and Pb for neutrons of an effective energy of 765 +\\/- 30 Mev. The neutrons were detected by observing the Cerenkov light from charged secondaries produced in a cylinder of Perspex. Large corrections

N. E. Booth; G. W. Hutchinson; B. Ledley

1958-01-01

180

Nuclear Cross Sections for 765 Mev Neutrons  

Microsoft Academic Search

Total cross sections have been measured for the elements H, D, Li, C, O, Al, Cu, Sb and Pb and absorption cross sections for C, Al, Cu and Pb for neutrons of an effective energy of 765 ± 30 Mev. The neutrons were detected by observing the Cerenkov light from charged secondaries produced in a cylinder of Perspex. Large corrections

N. E. Booth; G. W. Hutchinson; B. Ledley

1958-01-01

181

Diffraction Effects in Nuclear Cross Sections  

Microsoft Academic Search

Some of the most noticeable resonance structures in the energy dependence of nuclear cross sections and other reaction characteristics, for example, the kinetic energy and angular anisotropy, of fission fragments are correlated for different nuclei irrespective of the parity of their atomic number and mass number. The resonance structures in the neutron cross sections can also correlate with the structure

G. V. Anikin; V. G. Anikin

2003-01-01

182

Regional tertiary cross sections: Texas Gulf Coast  

Microsoft Academic Search

Regional studies of the Frio Formation along the Texas Gulf Coast were conducted to evaluate potential geothermal energy from deep, geopressured sandstone reservoirs. Published regional cross sections, unpublished cross sections provided by several major oil companies, and extensive micropaleontological and electrical-log files at the Bureau of Economic Geology served as basic data. These sections are meant to show gross regional

D. G. Debout; P. E. Luttrell; J. H. Seo

1976-01-01

183

Radar Absorbing Material Design.  

National Technical Information Service (NTIS)

Low observable platforms have extremely low radar cross section specifications that cannot be achieved by shaping alone. The application of radar absorbing material is necessary, in which case the appropriate constitutive parameters and thickness must be ...

C. K. Yuzcelik

2003-01-01

184

Photodetachment cross section for Ca sup minus  

SciTech Connect

Multiconfiguration Hartree-Fock calculations for photodetachment cross sections in Ca{sup {minus}} are reported, both to the {ital ks} {sup 2}{ital S} and {ital kd} {sup 2}{ital D} final state. Correlation is important to the binding of the 4{ital s}{sup 2}4{ital p} {sup 2}{ital P} state and also to the cross section. In the final state, correlation is particularly important for the {ital kd} partial cross section. The value of the electron affinity in Ca{sup {minus}} is critical to agreement in the length and velocity form of the cross section. Better agreement is obtained when a theoretical value is used. Agreement with an experimental photodetachment cross section is good.

Froese Fischer, C. (Department of Computer Science, Vanderbilt University, Box 6035B, Nashville, TN (USA)); Hansen, J.E. (Zeeman Laboratory, Plantage Muidergracht 4, NL-1018 TV Amsterdam, The Netherlands (NL))

1991-08-01

185

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

Microsoft Academic Search

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

V. Gopalakrishnan

2000-01-01

186

Calculated medium-energy fission cross sections  

SciTech Connect

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

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

1988-01-01

187

Benchmark cross sections for bottom quark production  

SciTech Connect

A summary is presented of theoretical expectations for the total cross sections for bottom quark production, for longitudinal and transverse momentum distributions, and for b, /bar b/ momentum correlations at Fermilab fixed target and collider energies.

Berger, E.L.

1988-01-07

188

ConcepTest: Cross Section Explaination  

NSDL National Science Digital Library

During fieldwork in the western U.S., an experienced geologist sketched the cross section below showing three different units of tilted rocks and their relative ages. What could you best infer from this diagram? a. ...

189

Power Corrections in Eikonal Cross Sections.  

National Technical Information Service (NTIS)

We discuss power corrections associated with the behavior of the perturbative running coupling in the eikonal approximation to Drell-Yan and other annihilation cross sections in hadron-hadron scattering. General properties of the eikonal approximation imp...

E. Laenen G. Sterman W. Vogelsang

2000-01-01

190

MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.  

SciTech Connect

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

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

2005-05-01

191

Status of Electron Transport Cross Sections.  

National Technical Information Service (NTIS)

This report describes recent developments and improvements pertaining to cross sections for electron-photon transport calculations. The topics discussed include: (1) electron stopping power (mean excitation energies, density-effect correction); (2) bremss...

S. M. Seltzer M. J. Berger

1982-01-01

192

International Evaluation of Neutron Cross Section Standards  

SciTech Connect

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. [National Institute of Standards and Technology, 100 Bureau Drive, Stop 8463, Gaithersburg, MD 20899-8463 (United States)], E-Mail: allan.carlson@nist.gov; Pronyaev, V.G. [Institute of Physics and Power Engineering, Bondarenko Sq. 1, 249 033 Obninsk, Kaluga Region (Russian Federation); Smith, D.L. [Argonne National Laboratory, 1710 Avenida del Mundo 1506, Coronado, CA 92118 (United States); Larson, N.M. [Bldg 5700, Rm 308, MS 6371, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6371 (United States); Chen, Zhenpeng [Physics Department, Tsinghua University, Beijing 100084 China (China); Hale, G.M. [Los Alamos National Laboratory, Group T-16, MS B-243, Los Alamos NM 87545 (United States); Hambsch, F.-J. [Neutron Physics Unit, EC-JRC-Institute for Reference Materials and Measurements, Retieseweg B-2440 Geel (Belgium); Gai, E.V. [Institute of Physics and Power Engineering, Bondarenko Sq. 1, 249 033 Obninsk, Kaluga Region (Russian Federation); Oh, Soo-Youl [HANARO Center, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Badikov, S.A. [Central Research Institute of Management, Economics and Information, Dmitrovskoe sh.2, Moscow 127434 (Russian Federation); Kawano, T. [Los Alamos National Laboratory, Group T-16, MS B-243, Los Alamos NM 87545 (United States); Hofmann, H.M. [Institut fuer Theoretische Physik III, 02.534/B2, Universitaet Erlangen-Nuernberg, Staudtstrasse 7, D-91058 Erlangen (Germany); Vonach, H.; Tagesen, S. [Institut fuer Isotopenforschung und Kernphysik der Universitaet Wien, Waehringerstrasse 17, A-1090 Vienna (Austria)

2009-12-15

193

Nuclear Cross Sections for 95Mev Neutrons  

Microsoft Academic Search

The total cross sections of twelve different elements were measured using the neutron beam from the 184-inch cyclotron operating with deuterons. Bismuth fission ionization chambers were employed as both monitor and detector in conventional \\

James Dejuren; Norman Knable

1950-01-01

194

46 CFR 64.25 - Cross section.  

Code of Federal Regulations, 2011 CFR

...section. 64.25 Section 64.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.25 Cross section. A tank...

2011-10-01

195

46 CFR 64.25 - Cross section.  

Code of Federal Regulations, 2012 CFR

...section. 64.25 Section 64.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.25 Cross section. A tank...

2012-10-01

196

Absorption cross section of canonical acoustic holes  

SciTech Connect

We compute numerically the absorption cross section of a canonical acoustic hole for sound waves with arbitrary frequencies. Our outputs are in full agreement with the expected low- and high-frequency limits.

Crispino, Luis C. B.; Oliveira, Ednilton S.; Matsas, George E. A. [Faculdade de Fisica, Universidade Federal do Para, 66075-110, Belem (Brazil); Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405-900, Sao Paulo, SP (Brazil)

2007-11-15

197

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

198

Calculation of ppgamma cross sections and asymmetries  

Microsoft Academic Search

Proton-proton bremsstrahlung cross sections and asymmetries are calculated in both the Gottschalk and Thorndike geometries. Calculations using model-dependent off-shell terms are compared to calculations where these terms are suppressed. In general, the ppgamma asymmetries are less sensitive to off-shell information than the corresponding ppgamma cross sections. These calculations also indicate that the asymmetry at 204 MeV is smoother than the

J. H. McGuire; W. A. Pearce

1971-01-01

199

Calculation of npgamma cross sections and asymmetries  

Microsoft Academic Search

Neutron-proton bremsstrahlung cross sections and asymmetries are calculated in both the Gottschalk and Thorndike geometries. The influence of off-shell terms is determined by comparing off-shell calculations to calculations using only elastic scattering parameters. The npgamma asymmetry is generally less sensitive to off-shell terms than the corresponding cross section. However, the off-shell influences in the npgamma cases are greater than in

J. H. McGuire; W. A. Pearce

1971-01-01

200

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

201

Thermal neutron capture cross section in deuterium  

SciTech Connect

The radiative thermal nD capture cross section sigma/sub D/ was measured by the time-of-flight method at the IBR-30 pulsed reactor using Ge(Li) detector, D/sub 2/O water sample and the sigma/sub Cl/ thermal cross section as the standard. The result 487(24) ..mu..b is in favor of the theoretical value found in the frame of the three body problem.

Alfimenkov, V.P.; Borzakov, S.B.; Wierzbicki, J.; Osipenko, B.P.; Pikelner, L.B.; Tishin, V.G.; Sharapov, E.I.

1980-09-01

202

Nonelastic Scattering Cross Sections for Fast Neutrons  

Microsoft Academic Search

Measurements have been made of the nonelastic cross sections of neutrons in Be, C, Al, Ti, Cr, Fe, Ni, Cu, Ag, Sn, Pb, and Bi. These cross sections include all processes except elastic scattering. The experiments have been carried out with monoenergetic neutrons of 3.5, 4.7, 7.1, 12.7, and 14.1 Mev. The neutrons were produced with a Van de Graaff

H. L. Taylor; O. Lönsjö; T. W. Bonner

1955-01-01

203

Thermal Neutron Capture Cross Section in Deuterium  

Microsoft Academic Search

The radiative thermal nD capture cross section sigma\\/sub D\\/ was measured by the time-of-flight method at the IBR-30 pulsed reactor using Ge(Li) detector, DâO water sample and the sigma\\/sub Cl\\/ thermal cross section as the standard. The result 487(24) ..mu..b is in favor of the theoretical value found in the frame of the three body problem.

V. P. Alfimenkov; S. B. Borzakov; J. Wierzbicki; B. P. Osipenko; L. B. Pikelner; V. G. Tishin; E. I. Sharapov

1980-01-01

204

Neutron capture cross section of ²¹Am  

Microsoft Academic Search

The neutron capture cross section of ²¹Am for incident neutrons from 0.02 eV to 320 keV has been measured with the detector for advanced neutron capture experiments (DANCE) at the Los Alamos Neutron Science Center. The thermal neutron capture cross section was determined to be 665{+-}33 b. Our result is in good agreement with other recent measurements. Resonance parameters for

M. Jandel; T. A. Bredeweg; E. M. Bond; M. B. Chadwick; R. R. Clement; A. Couture; J. M. ODonnell; R. C. Haight; T. Kawano; R. Reifarth; R. S. Rundberg; J. L. Ullmann; D. J. Vieira; J. B. Wilhelmy; J. M. Wouters; U. Agvaanluvsan; W. E. Parker; C. Y. Wu; J. A. Becker

2008-01-01

205

Neutron capture cross section of Am241  

Microsoft Academic Search

The neutron capture cross section of Am241 for incident neutrons from 0.02 eV to 320 keV has been measured with the detector for advanced neutron capture experiments (DANCE) at the Los Alamos Neutron Science Center. The thermal neutron capture cross section was determined to be 665±33 b. Our result is in good agreement with other recent measurements. Resonance parameters for

M. Jandel; T. A. Bredeweg; E. M. Bond; M. B. Chadwick; R. R. Clement; A. Couture; J. M. O'Donnell; R. C. Haight; T. Kawano; R. Reifarth; R. S. Rundberg; J. L. Ullmann; D. J. Vieira; J. B. Wilhelmy; J. M. Wouters; U. Agvaanluvsan; W. E. Parker; C. Y. Wu; J. A. Becker

2008-01-01

206

Shuttle rendezvous radar performance: evaluation and simulation  

Microsoft Academic Search

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

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

1989-01-01

207

Track structure studies and cross section calculations  

NASA Astrophysics Data System (ADS)

Charged particle Monte Carlo MC track structre simulations are a useful tool for the understanding of early physical and chemical stages of radiation actions on matter They provide detailed information on highly inhomogeneous spatial distributions of energy depositions interaction types and radical species produced This information is used in Radiation Biology to estimate radiation damage to DNA and other cellular structures e g strand break yields and fragment size distributions Monte Carlo track structure simulations follow the primary as well as all secondary particles event-by-event from starting or ejection energies to total stopping They require reliable cross sections for elastic scattering ionization excitation and charge changing events total cross sections as well as energy and angle differential cross sections of the incident charged particles electrons protons alphas light and heavy ions with the atoms and molecules of the material under consideration Cross sections with liquid water are of special interest since liquid water serves as a substitute for soft tissue Ionization and excitation cross sections for charged particles are normally calculated within the framework of the relativistic plane wave first Born approximation PWBA In this theory the double differential cross section differential in energy and momentum transfer can be separated into kinematic factors and the generalized oscillator strength GOS for single atoms in the gas phase or the dielectric response function

Dingfelder, M.

208

Fission cross section measurements at LANSCE  

NASA Astrophysics Data System (ADS)

Neutron induced fission cross sections of actinides are measured at the Los Alamos Neutron Science Center (LANSCE) in support of the Advanced Fuel Cycle Initiative (AFCI) and the National Nuclear Security Administration (NNSA). Nuclear technologies are increasingly dependent on advanced simulations for design and licensing requirements, and nuclear cross section data are important input parameters for the simulation tools. Fast nuclear reactor and stockpile stewardship applications often share nuclear data needs and requirements, and the LANSCE neutron source is ideal for measuring many of these data. The fission cross section measurements are guided by sensitivity studies performed in support of the AFCI program, as well as requests from NNSA. Recent results for the Pu-239 and Pu-241 fission cross sections from 0.01 eV to 200 MeV will be presented, and the discrepancy with current evaluations of the Pu-241 fission cross section discussed. Ongoing activities to extend the fission program will be presented, such as the development of a Time Projection Chamber (TPC) to significantly improve the experimental accuracies in fission cross section measurements.

Tovesson, Fredrik; Hill, Tony

2009-10-01

209

Determining (n,?) cross sections using surrogate reactions  

NASA Astrophysics Data System (ADS)

Direct measurements of neutron-reaction cross sections on unstable nuclei are extremely challenging due to the difficulties associated with radioactive targets and neutron beams. Indirect methods, such as the surrogate reaction method, are currently the only feasible way to determine many of the cross sections for radioactive nuclei that are of interest to nuclear astrophysics, nuclear energy, and other applications. We have used the surrogate reaction method to determine (n,?) cross sections for ^153,155,157Gd nuclei at energies up to 3 MeV through inelastic proton scattering on stable targets. The STARS/LiBerACE silicon and germanium detector arrays were used to detect ? rays in coincidence with the scattered protons to determine ?-ray exit-channel probabilities. Techniques are being explored to extract reliable cross sections at energies for which the Weisskopf-Ewing limit of the Hauser-Feshbach theory is not applicable. This measurement will provide the first determination of the (n,?) cross section for ^153Gd, an s-process branch-point nucleus with a half-life of 240 days. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Scielzo, Nicholas; Escher, Jutta

2009-10-01

210

Status of the Neutron Cross Section Standards  

NASA Astrophysics Data System (ADS)

An international evaluation of the neutron cross section standards was recently completed. Many of these standards are used directly in neutron dosimetry for fluence determination. Also, almost all measurements of other dosimetry cross sections have been made relative to neutron cross section standards. Evaluations were obtained for the 1H(n,n), 6Li(n,t), 10B(n,?), 10B(n,?1?), Au(n,?), 235U(n,f) and 238U(n,f) standard cross sections. This work also led to evaluations for the 238U(n,?) and 239Pu(n,f) cross sections, which are not standards, but are used for neutron dosimetry. The new evaluations are generally larger than the ENDF/B-VI evaluations by as much as several percent. Also improved thermal constants were obtained that are in good agreement with the ENDF/B-VI values. The data obtained from this evaluation process were used to produce new evaluations for the new ENDF/B-VII library. Recent measurements are reviewed and the effect of the new evaluations on fluence determinations is shown.

Carlson, A. D.

2009-08-01

211

Estimating Mean Fluctuating Cross Section in the Presence of White Gaussian Noise  

Microsoft Academic Search

The mean cross section of a fluctuating radar echo is estimated by the sample mean of a sequence of pulse to pulse echo power measurements. The variance of the sample mean decreases with the number of measurements or observations, but not proportionally because, in general, the measurements are correlated. This phenomenon is well known, but the effect of receiver noise

Harry Urkowitz; Sheldon L. Katz

1992-01-01

212

Calculation of np? cross sections and asymmetries  

NASA Astrophysics Data System (ADS)

Neutron-proton bremsstrahlung cross sections and asymmetries are calculated in both the Gottschalk and Thorndike geometries. The influence of off-shell terms is determined by comparing off-shell calculations to calculations using only elastic scattering parameters. The np? asymmetry is generally less sensitive to off-shell terms than the corresponding cross section. However, the off-shell influences in the np? cases are greater than in the corresponding pp? cases. Furthermore, the np? cross sections tend to be large in the same region where the interesting off-shell effects are large. Work supported in part by the Air Force Office of Aerospace Research US Air Force under Grant No. 69-817; and in part by the Research Council.

McGuire, J. H.; Pearce, W. A.

1971-02-01

213

Calculation of pp? cross sections and asymmetries  

NASA Astrophysics Data System (ADS)

Proton-proton bremsstrahlung cross sections and asymmetries are calculated in both the Gottschalk and Thorndike geometries. Calculations using model-dependent off-shell terms are compared to calculations where these terms are suppressed. In general, the pp? asymmetries are less sensitive to off-shell information than the corresponding pp? cross sections. These calculations also indicate that the asymmetry at 204 MeV is smoother than the Rochester experiment suggests. Calculations of the pp? cross section at extreme forward angles in the Gottschalk geometry suggest large model-dependent effects. Work supported in part by the Air Force Office of Aerospace Research US Air Force under Grant No. 69-817; and in part by the Research Council.

McGuire, J. H.; Pearce, W. A.

1971-02-01

214

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

215

Photodisintegration Cross Section of {sup 241}Am  

SciTech Connect

The photodisintegration cross section of radioactive {sup 241}Am has been obtained for the first time using monoenergetic {gamma}-ray beams from the HI{gamma}S facility. The induced activity of {sup 240}Am produced via the {sup 241}Am({gamma},n) reaction in the {gamma}-ray energy range from 9.5 to 16 MeV was measured by the activation technique utilizing high resolution HPGe detectors. The {sup 241}Am({gamma},n) cross section was determined both by measuring the absolute {gamma}-ray flux and by comparison to the {sup 197}Au({gamma},n) and {sup 58}Ni({gamma},n) cross section standards. The experimental data for the {sup 241}Am({gamma},n) reaction in the giant dipole resonance energy region is compared with statistical nuclear-model calculations.

Tonchev, A. P.; Howell, C. R.; Hutcheson, A.; Kwan, E.; Rusev, G.; Tornow, W. [Duke University and TUNL, Durham NC 27708 (United States); Hammond, S.; Karwowski, H. J. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill NC 27599 (United States); Huibregtse, C.; Kelley, J. H. [North Carolina State University and TUNL, Raleigh NC 27695 (United States); Vieira, D. J.; Wilhelmy, J. B. [Los Alamos National Laboratory, Los Alamos NM 87545 (United States)

2009-03-10

216

Optical Model and Cross Section Uncertainties  

SciTech Connect

Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.

Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.

2009-10-05

217

Cross sections of neutron-induced reactions  

SciTech Connect

We study the properties of the neutron-nucleus total and reaction cross sections for several nuclei. We have applied an analytical model, the nuclear Ramsauer model, justified it from the nuclear reaction theory approach, and extracted the values of 12 parameters used in the model. The given parametrization has an advantage as phenomenological optical model potentials are limited up to 150-200 MeV. The present model provides good estimates of the total cross sections for several nuclei particularly at high energies.

Mukhopadhyay, Tapan; Lahiri, Joydev; Basu, D. N. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India)

2010-10-15

218

Neutron Capture Cross Section of ^239Pu  

NASA Astrophysics Data System (ADS)

The ^239Pu(n,?) cross section has been measured at the Los Alamos Neutron Science Center (LANSCE). The Detector for Advanced Neutron Capture Experiments (DANCE) provided a highly segmented 4? measurement of the energy and multiplicity distributions for emitted ?-rays, while a PPAC detected coincidence fission fragments. The simultaneous measurement of (n,?) and (n,f) events resulting from a single sample allowed the (n,?) cross section to be measured as a ratio to fission with reduced systematic uncertainty. Results from the current analysis will be presented.

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

2012-10-01

219

Total cross section in ?? collisions at LEP  

Microsoft Academic Search

The reaction e+e??e+e??????e+e?hadrons for quasi-real photons is studied using data from s=183 GeV up to 202 GeV. Results on the total cross sections ?(e+e??e+e?hadrons) and ?(???hadrons) are given for the two-photon centre-of-mass energies 5 GeV?W???185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the

M. Acciarri; P. Achard; O. Adriani; M. Aguilar-Benitez; J. Alcaraz; G. Alemanni; J. Allaby; A. Aloisio; M. G. Alviggi; G. Ambrosi; H. Anderhub; V. P. Andreev; T. Angelescu; F. Anselmo; A. Arefiev; T. Azemoon; T. Aziz; P. Bagnaia; A. Bajo; L. Baksay; A. Balandras; S. V. Baldew; S. Banerjee; A. Barczyk; R. Barillère; P. Bartalini; M. Basile; N. Batalova; R. Battiston; A. Bay; F. Becattini; U. Becker; F. Behner; L. Bellucci; R. Berbeco; J. Berdugo; P. Berges; B. Bertucci; B. L. Betev; S. Bhattacharya; M. Biasini; A. Biland; J. J. Blaising; S. C. Blyth; G. J. Bobbink; A. Böhm; L. Boldizsar; B. Borgia; D. Bourilkov; M. Bourquin; S. Braccini; J. G. Branson; F. Brochu; A. Buffini; A. Buijs; J. D. Burger; W. J. Burger; X. D. Cai; M. Capell; G. Carlino; A. M. Cartacci; J. Casaus; G. Castellini; F. Cavallari; N. Cavallo; C. Cecchi; M. Cerrada; F. Cesaroni; M. Chamizo; Y. H. Chang; U. K. Chaturvedi; M. Chemarin; A. Chen; G. Chen; H. F. Chen; H. S. Chen; G. Chiefari; L. Cifarelli; F. Cindolo; C. Civinini; I. Clare; R. Clare; G. Coignet; N. Colino; S. Costantini; F. Cotorobai; A. Csilling; S. Cucciarelli; T. S. Dai; R. D'Alessandro; P. Déglon; A. Degré; K. Deiters; E. Delmeire; P. Denes; F. DeNotaristefani; M. Diemoz; M. Dierckxsens; C. Dionisi; M. Dittmar; A. Dominguez; A. Doria; M. T. Dova; D. Duchesneau; D. Dufournaud; P. Duinker; A. Engler; F. J. Eppling; F. C. Erné; A. Ewers; P. Extermann; M. Fabre; M. A. Falagan; S. Falciano; A. Favara; J. Fay; O. Fedin; M. Felcini; T. Ferguson; H. Fesefeldt; E. Fiandrini; J. H. Field; F. Filthaut; P. H. Fisher; I. Fisk; G. Forconi; K. Freudenreich; C. Furetta; Yu. Galaktionov; S. N. Ganguli; P. Garcia-Abia; M. Gataullin; S. S. Gau; S. Gentile; N. Gheordanescu; S. Giagu; Z. F. Gong; G. Grenier; O. Grimm; M. W. Gruenewald; M. Guida; V. K. Gupta; A. Gurtu; L. J. Gutay; D. Haas; A. Hasan; D. Hatzifotiadou; T. Hebbeker; A. Hervé; P. Hidas; J. Hirschfelder; H. Hofer; G. Holzner; H. Hoorani; S. R. Hou; Y. Hu; I. Iashvili; B. N. Jin; L. W. Jones; I. Josa-Mutuberr??a; R. A. Khan; D. Käfer; M. Kaur; M. N. Kienzle-Focacci; D. Kim; J. K. Kim; J. Kirkby; D. Kiss; W. Kittel; A. Klimentov; A. C. König; M. Kopal; A. Kopp; V. Koutsenko; M. Kräber; R. W. Kraemer; W. Krenz; A. Krüger; A. Kunin; I. Laktineh; G. Landi; M. Lebeau; A. Lebedev; P. Lebrun; P. Lecomte; P. Lecoq; H. J. Lee; R. Leiste; P. Levtchenko; C. Li; S. Likhoded; C. H. Lin; W. T. Lin; F. L. Linde; L. Lista; Z. A. Liu; W. Lohmann; E. Longo; Y. S. Lu; K. Lübelsmeyer; C. Luci; D. Luckey; L. Lugnier; L. Luminari; W. Lustermann; W. G. Ma; M. Maity; L. Malgeri; A. Malinin; C. Maña; D. Mangeol; J. Mans; G. Marian; J. P. Martin; F. Marzano; K. Mazumdar; R. R. McNeil; S. Mele; L. Merola; M. Meschini; W. J. Metzger; A. Mihul; H. Milcent; G. Mirabelli; J. Mnich; G. B. Mohanty; T. Moulik; G. S. Muanza; A. J. M. Muijs; B. Musicar; M. Musy; M. Napolitano; F. Nessi-Tedaldi; H. Newman; T. Niessen; A. Nisati; H. Nowak; R. Ofierzynski; G. Organtini; A. Oulianov; C. Palomares; D. Pandoulas; S. Paoletti; P. Paolucci; R. Paramatti; H. K. Park; I. H. Park; G. Passaleva; S. Patricelli; T. Paul; M. Pauluzzi; C. Paus; F. Pauss; M. Pedace; S. Pensotti; D. Perret-Gallix; B. Petersen; D. Piccolo; F. Pierella; M. Pieri; P. A. Piroué; E. Pistolesi; V. Plyaskin; M. Pohl; V. Pojidaev; H. Postema; J. Pothier; D. O. Prokofiev; J. Quartieri; G. Rahal-Callot; M. A. Rahaman; P. Raics; N. Raja; R. Ramelli; P. G. Rancoita; R. Ranieri; A. Raspereza; G. Raven; P. Razis; D. Ren; M. Rescigno; S. Reucroft; S. Riemann; K. Riles; J. Rodin; B. P. Roe; L. Romero; A. Rosca; S. Rosier-Lees; S. Roth; C. Rosenbleck; B. Roux; J. A. Rubio; G. Ruggiero; H. Rykaczewski; S. Saremi; S. Sarkar; J. Salicio; E. Sanchez; M. P. Sanders; C. Schäfer; V. Schegelsky; S. Schmidt-Kaerst; D. Schmitz; H. Schopper; D. J. Schotanus; G. Schwering; C. Sciacca; A. Seganti; L. Servoli; S. Shevchenko; N. Shivarov; V. Shoutko; E. Shumilov; A. Shvorob; T. Siedenburg; D. Son; B. Smith; P. Spillantini; M. Steuer; D. P. Stickland; A. Stone; B. Stoyanov; A. Straessner; K. Sudhakar; G. Sultanov; L. Z. Sun; S. Sushkov; H. Suter; J. D. Swain; Z. Szillasi; T. Sztaricskai; X. W. Tang; L. Tauscher; L. Taylor; B. Tellili; D. Teyssier; C. Timmermans; Samuel C. C. Ting; S. M. Ting; S. C. Tonwar; J. Tóth; C. Tully; K. L. Tung; Y. Uchida; J. Ulbricht; E. Valente; G. Vesztergombi; I. Vetlitsky; D. Vicinanza; G. Viertel; S. Villa; M. Vivargent; S. Vlachos; I. Vodopianov; H. Vogel; H. Vogt; I. Vorobiev; A. A. Vorobyov; A. Vorvolakos; M. Wadhwa; W. Wallraff; M. Wang; X. L. Wang; Z. M. Wang; A. Weber; M. Weber; P. Wienemann; H. Wilkens; S. X. Wu; S. Wynhoff; L. Xia; Z. Z. Xu; J. Yamamoto; B. Z. Yang; C. G. Yang; H. J. Yang; M. Yang; J. B. Ye; S. C. Yeh; An. Zalite; Yu. Zalite; Z. P. Zhang; G. Y. Zhu; R. Y. Zhu; A. Zichichi; G. Zilizi; B. Zimmermann; M. Zöller

2001-01-01

220

Covariance Evaluation Methodology for Neutron Cross Sections  

SciTech Connect

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

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

2008-09-01

221

Simple Calculations of Proton SEU Cross Sections from Heavy Ion Cross Sections  

Microsoft Academic Search

Simple expressions, based on previous analytical and empirical models for the energy deposited by protons through their p+Si interactions, are proposed for calculating proton induced SEU cross sections from heavy ion cross sections in devices with sub-micron sensitive volumes. Calculations for modern devices yield good agreement with the experiments. The implications on calculating SEU rates in space are discussed

J. Barak

2006-01-01

222

Hadron-nucleon total cross section fluctuations from hadron-nucleus total cross sections  

Microsoft Academic Search

The extent to which information about fluctuations in hadron-nucleon total cross sections in the frozen approximation can be extracted from very high energy hadron-nucleus total cross section measurements for a range of heavy nuclei is discussed. The corrections to the predictions of Glauber theory due to these fluctuations are calculated for several models for the distribution functions, and differences of

David R. Harrington

1995-01-01

223

Polarization control of microwave emission from high power rectangular cross-section gyrotron devices  

Microsoft Academic Search

Results are summarized of experiments on a gyrotron utilizing a rectangular-cross-section (RCS) cavity region. The major issue under investigation is polarization control of microwave emission as a function of magnetic field. The electron beam driver is the Michigan Electron Long Beam Accelerator (MELBA) at parameters: V=0.8 MV, Idiode=1-10 kA, Itube=0.1=0.5 kA, and te-beam=0.4-1.0 ?s. The annular e-beam is spun up

Jonathan M. Hochman; Ronald M. Gilgenbach; Reginald L. Jaynes; Joshua I. Rintamaki; Y. Y. Lau; William E. Cohen; Chris W. Peters; Thomas A. Spencer

1998-01-01

224

Jet Cross Sections in Leptoproduction from QCD.  

National Technical Information Service (NTIS)

We have calculated the longitudinal and other polarization dependent cross sections for jet production in deep inelastic ep, nu p and anti nu p scattering up to order alpha /sub s/ of the quark-gluon coupling constant. Fragmentation of final state partons...

C. Rumpf G. Kramer J. Willrodt

1980-01-01

225

Top production cross section from CDF  

SciTech Connect

Recent top physics results from the CDF at a center-of-mass energy of 1.96 TeV are presented. Measurements of the t{bar t} production cross section in all three decay channels, using a set of complementary experimental methods, are presented as well as results of a search for single top production.

Taffard, Anyes; /Illinois U., Urbana

2004-12-01

226

Thermal Neutron Absorption Cross Section of Deuterium  

Microsoft Academic Search

The absorption cross section of deuterium for 2200-m\\/sec neutrons has been related to that of boron by intercomparison with lithium. A value of 0.57+\\/-0.01 millibarn for deuterium, based on a measured value of 755 barns for boron, has been obtained.

Louis Kaplan; G. R. Ringo; K. E. Wilzbach

1952-01-01

227

Cross-sectional area of the mandible  

Microsoft Academic Search

Purpose: The anatomy of the mandible was examined by measuring the cross-sectional area (CSA) of multiple regions of 10 fully dentulous hemimandibles to provide a better understanding of regional structural differences that may have implications regarding biomechanical strength, surgical reconstruction, and fracture site frequency.Materials and Methods: Fifteen cuts from the condyle to the symphysis were made of each hemimandible (n

Warren Schubert; Brian J Kobienia; Richard A Pollock

1997-01-01

228

SSC 50 mm dipole cross section  

Microsoft Academic Search

In this paper we present the magnetic design of the two dimensional coil and iron cross section, referred to as DSX201\\/W6733, for the 50 mm aperture main ring dipole magnet for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of

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

1991-01-01

229

A Pebble Bed Reactor cross section methodology  

Microsoft Academic Search

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

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

2009-01-01

230

The Total Neutron Cross Section of Nitrogen  

Microsoft Academic Search

The total cross section of nitrogen has been measured for neutrons in the energy range 200 to 1800 kev, using scatterers of liquid nitrogen and of lithium azide. Eleven resonances were found, corresponding to excited states in the compound nucleus N15, with natural widths of from 3 to 54 kev. Nine of these can be identified with resonances previously known

J. J. Hinchey; P. H. Stelson; W. M. Preston

1952-01-01

231

Nuclear cross sections for nuclear energy  

Microsoft Academic Search

Practical payoffs from utilizing basic research and nuclear cross sections to improve efficiency and safety and cut operating costs in nuclear power plants are reviewed. Improvements in the performance of light water reactors, fast breeders, thermal-neutron breeders, fusion arrangements, handling of fission products, developing safeguards against theft of nuclear materials, and radioactive wastes disposal are discussed. Careful attention to plutonium

J. L. Fowler; William W. Havens

1976-01-01

232

Nuclear Cross Sections for 270Mev Neutrons  

Microsoft Academic Search

The total cross sections of eleven different elements were measured for the neutrons resulting from the bombardment of a 2-in. Be target by the 350-Mev protons of the 184-in. cyclotron. Bismuth fission ionization chambers served as the neutron detectors and had an estimated mean neutron detection energy of 270 Mev for the measurements. The attenuating materials were placed inside the

James Dejuren

1950-01-01

233

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

234

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

235

Total dissociation cross section of halo nuclei.  

National Technical Information Service (NTIS)

Calculations of the total dissociation cross section is performed in the impact parameter representation. The case of (sup 11)Be and (sup 11)Li loosing one and two neutron(s), respectively, by collision on a (sup 12)C target, which remains in its ground s...

J. Formanek R. J. Lombard

1996-01-01

236

Neutron capture cross section of Am241  

NASA Astrophysics Data System (ADS)

The neutron capture cross section of Am241 for incident neutrons from 0.02 eV to 320 keV has been measured with the detector for advanced neutron capture experiments (DANCE) at the Los Alamos Neutron Science Center. The thermal neutron capture cross section was determined to be 665±33 b. Our result is in good agreement with other recent measurements. Resonance parameters for En<12 eV were obtained using an R-matrix fit to the measured cross section. The results are compared with values from the ENDF/B-VII.0, Mughabghab, JENDL-3.3, and JEFF-3.1 evaluations. ?n neutron widths for the first three resonances are systematically larger by 5-15% than the ENDF/B-VII.0 values. The resonance integral above 0.5 eV was determined to be 1553±7 b. Cross sections in the resolved and unresolved energy regions above 12 eV were calculated using the Hauser-Feshbach theory incorporating the width-fluctuation correction of Moldauer. The calculated results agree well with the measured data, and the extracted averaged resonance parameters in the unresolved resonance region are consistent with those for the resolved resonances.

Jandel, M.; Bredeweg, T. A.; Bond, E. M.; Chadwick, M. B.; Clement, R. R.; Couture, A.; O'Donnell, J. M.; Haight, R. C.; Kawano, T.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Agvaanluvsan, U.; Parker, W. E.; Wu, C. Y.; Becker, J. A.

2008-09-01

237

Hydrodynamics of tubes of varying cross section  

Microsoft Academic Search

A method is suggested of reducing the hydrodynamic resistance by replacing circular cylindrical tubes (CT) by socalled asymmetrical wavy tubes of varying cross section with long exist cone and short nozzle portions. Mathematical simulation of laminar motion of an incompressible fluid (the Navier-Stokes equations) has shown that a change in geometric parameters can change the resistance substantially, making it larger

I. L. Povkh; N. V. Finoshin

1992-01-01

238

RCS simulations on deformed corner reflectors applying SBR code SIGRAY  

Microsoft Academic Search

Corner reflectors play a major role in the calibration of radar systems. Because of their increasing accuracy the requirements on the calibration are also growing. The influence of geometry deformations of reflectors, caused by insufficient production accuracy or outside exposure, and by dirt, water film, snow or snow slush on the RCS is often neglected. Investigations on these topics have

E. Kemptner

2010-01-01

239

240 GHZ Polarimetric Compact Range for Scale Model RCS Measurements.  

National Technical Information Service (NTIS)

A fully-polarimetric compact radar range operating at 240 GHz has been developed for obtaining Ku-band RCS measurements on 1:16th scale model targets. The transceiver consists of dual fast-switching, stepped, CW X-band synthesizers driving dual X24 transm...

G. B. DeMartinis M. J. Coulombe R. H. Giles T. M. Horgan W. E. Nixon

2010-01-01

240

Hadronic diffractive cross sections and the rise of the total cross section  

NASA Astrophysics Data System (ADS)

A model for high-energy hadronic cross sections is proposed. It is based on Regge theory and perturbative QCD, and includes soft and hard mechanisms as well as diffractive processes. The validity range of Regge-pole theory in the description of total, elastic, single-, and double-diffractive cross sections is investigated and inconsistencies found already at CERN LHC and/or SSC energies. Examining unitarity constraints, modifications of the cross section formulas are proposed which allow a continued use of formulas in the Regge spirit to describe elastic and diffractive events. The nondiffractive cross section is allowed to rise at a rate consistent with unitarization of multiple parton-parton scatterings. However, in our picture, the rise of the total cross section with increasing energy is only partly due to the minijet cross sections; the diffractive topologies rise as well. Fully differential distributions are given and convenient parametrizations derived for the integrated rates of elastic and diffractive events. Predictions for the various partial cross sections at Fermilab Tevatron, LHC, and SSC energies are given and compared to other estimates.

Schuler, Gerhard A.; Sjöstrand, Torbjörn

1994-03-01

241

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

NASA Astrophysics Data System (ADS)

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.; Arndt, R. A.; Briscoe, W. J.; Paris, M. W.; Strakovsky, I. I.; Workman, R. L.

2011-06-01

242

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

NASA Astrophysics Data System (ADS)

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.

1985-05-01

243

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

244

Neutron cross section standards and flux determinations above thermal energies  

Microsoft Academic Search

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

1975-01-01

245

Radar cross section reduction by lumped, linear, passive loading  

SciTech Connect

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

Bevensee, R.M.

1985-10-01

246

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

247

Electron-collision cross sections for iodine  

SciTech Connect

We present results from a joint experimental and theoretical study of elastic electron scattering from atomic iodine. The experimental results were obtained by subtracting known cross sections from the measured data obtained with a pyrolyzed mixed beam containing a variety of atomic and molecular species. The calculations were performed using both a fully relativistic Dirac B-spline R-matrix (close-coupling) method and an optical model potential approach. Given the difficulty of the problem, the agreement between the two sets of theoretical predictions and the experimental data for the angle-differential and the angle-integrated elastic cross sections at 40 eV and 50 eV is satisfactory.

Zatsarinny, O.; Bartschat, K. [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Garcia, G. [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Madrid E-28006 (Spain); Blanco, F. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Hargreaves, L.R.; Jones, D.B.; Murrie, R.; Brunton, J.R. [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Brunger, M.J. [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603, Kuala Lumpur (Malaysia); Hoshino, M. [Department of Materials and Life Sciences, Sophia University, Chiyoda ku, Tokyo 102-8554 (Japan); Buckman, S.J. [ARC Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2011-04-15

248

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

249

Sketching cross sections with a portable microcomputer  

SciTech Connect

Computer applications have been carried to the field long ago by geophysicists and their dog houses. The advent of inexpensive battery-powered microcomputers promises to allow the field geologist to participate in this application. The field geologist may record data directly onto a computer-readable medium and calculate statistics or plot a cross section. A program for routine plotting of cross sections in the field has been developed and field-tested. The program proved to be useful to 30 computer-illiterate geologists on a 6-week mapping project in New Mexico. The program allows the user to control vertical exaggeration and displays the correct apparent dip along the chosen line of section. Cubic-spline interpolation is used to plot both topography and folded bedding planes. The program executes in Pascal on an Apple IIc in a few seconds.

Kimberley, M.M.

1985-02-01

250

Differential cross sections for fragmentation of positronium  

NASA Astrophysics Data System (ADS)

Cross sections differential with respect to energy and angle of ejected positrons and electrons for Ps(1s) fragmentation in collision with He, Ne, Ar, Kr and Xe targets are reported. For Ne, Ar, Kr and Xe, only the case where the target is not excited (target elastic collisions) is considered. For He, fragmentation with target excitation/ionization (target inelastic collisions) is also studied. The impulse approximation has been used for target elastic fragmentation, the first Born approximation for target inelastic processes.

Walters, H. R. J.; Starrett, C.; McAlinden, Mary T.

2006-06-01

251

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

252

Inclusive jet cross section at D0  

SciTech Connect

Preliminary measurement of the central ({vert_bar}{eta}{vert_bar} {<=} 0.5) inclusive jet cross sections for jet cone sizes of 1.0, 0.7, and 0.5 at D{null} based on the 1992-1993 (13.7 {ital pb}{sup -1}) and 1994-1995 (90 {ital pb}{sup -1}) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made.

Bhattacharjee, M. [Delhi Univ. (India). Dept. of Physics and Astrophysics

1996-09-01

253

Neutron cross sections for fusion. [Review  

Microsoft Academic Search

First generation fusion reactors will most likely be based on the ³H(d,n)⁴He reaction, which produces 14-MeV neutrons. In these reactors, both the number of neutrons and the average neutron energy will be significantly higher than for fission reactors of the same power. Accurate neutron cross section data are therefore of great importance. They are needed in present conceptual designs to

Haight

1979-01-01

254

Neutron total cross section for tritium  

Microsoft Academic Search

The neutron total cross sections for hydrogen, deuterium, and tritium have been measured with the neutron-time-of-flight technique. The tritium data span the neutron energy range from 60 keV to 80 MeV, with an overall systematic uncertainty which varies from 0.5% for energies below 17 MeV to 2% at the highest energy measured; the statistical uncertainties exceed these values only below

T. W. Phillips; B. L. Berman; J. D. Seagrave

1980-01-01

255

Experimental test of the bremsstrahlung cross section  

Microsoft Academic Search

The bremsstrahlung cross section has been studied by measuring the activity induced in 63Cu by electrodisintegration and when thin radiators of Cu, Mo, Ta, and Th were placed in the electron beam just ahead of the target. The electron energies were varied from 13.5 to 60 MeV for the electrodisintegration and from 20 to 60 MeV for the radiator-in measurements;

M. N. Martins; E. Hayward; G. Lamaze; X. K. Maruyama; F. J. Schima; E. Wolynec

1984-01-01

256

Capture cross sections for very heavy systems  

Microsoft Academic Search

In intermediate-mass systems, collective excitations of the target and projectile can greatly enhance the subbarrier capture\\u000a cross section ?\\u000a cap by giving rise to a distribution of Coulomb barriers. For such systems, capture essentially leads directly to fusion [formation\\u000a of a compound nucleus (CN)], which then decays through the emission of light particles (neutrons, protons, and alpha particles).\\u000a Thus, the

N. Rowley; N. Grar; S. S. Ntshangase; R. A. Bark; S. V. Förtsch; J. J. Lawrie; E. A. Gueorguieva; S. M. Maliage; L. J. Mudau; S. M. Mullins; O. M. Ndwandwe; R. Neveling; G. Sletten; F. D. Smith; C. Theron

2006-01-01

257

Neutron radiative capture cross sections, total cross sections, and average resonance parameters for the tin isotopes  

Microsoft Academic Search

Cross sections for radiative capture of neutrons in the energy region 20--450 keV and total cross sections from 20 to 1400 keV for the isotopes {sup 112,114--120,122,124}Sn and the natural mixture of tin have been measured by the time-of-flight method in the pulsed electrostatic accelerator EG-1 at our institute. The experimental data were analyzed in the framework of the statistical

V. M. Timokhov; M. V. Bokhovko; A. G. Isakov; L. E. Kazakov; V. N. Kononov; G. N. Manturov; E. D. Poletaev; V. G. Pronyaev

1989-01-01

258

Microscopic optical-model calculations of neutron total cross sections and cross section differences  

Microsoft Academic Search

Using the microscopic optical model of Jeukenne, Lejeune, and Mahaux we have calculated the absolute neutron total cross sections and cross section differences of 140Ce, 139Ce, 141Ce, 142Ce, and 40Ca, 44Ca from 6-60 MeV and have made comparisons with experimental data. Except for 142Ce, reasonable agreement with the mass 140 data was achieved with proton densities rhop of the nuclei

H. S. Camarda; F. S. Dietrich; T. W. Phillips

1989-01-01

259

Hadronic diffractive cross sections and the rise of the total cross section  

Microsoft Academic Search

A model for high-energy hadronic cross sections is proposed. It is based on Regge theory and perturbative QCD, and includes soft and hard mechanisms as well as diffractive processes. The validity range of Regge-pole theory in the description of total, elastic, single-, and double-diffractive cross sections is investigated and inconsistencies found already at CERN LHC and\\/or SSC energies. Examining unitarity

Gerhard A. Schuler; Torbjörn Sjöstrand

1994-01-01

260

Cross-section reconstruction during uniaxial loading  

NASA Astrophysics Data System (ADS)

The inelastic response of materials to applied uniaxial loading is typically measured using tensile or compressive specimens of an initially circular cross-section. Under deformation, this cross-section may become elliptical due to anisotropic material behaviour. An optical technique for measuring the elliptical deformation of anisotropic, homogeneous cylindrical specimens undergoing uniaxial deformation is presented. It enables the quantification of anisotropic deformation in situ and provides data for material characterization. Three or more silhouette views of a specimen are obtained using multiple cameras or mirrored views. The positions of the edges are computed using a sub-pixel edge detection method, and 3D tangent rays from the camera through these positions are calculated. These bounding tangents are used as the basis for an elliptical fit by least squares at cross-sections along the length of the specimen. Stochastic error estimates are performed by simulation of the experiment. Error estimates, for the experimental set-up used, are also calculated by reconstructing elliptical prisms of precisely measured dimensions. Example reconstructions from specimens of rolled titanium deformed plastically in tension at quasi-static (7 × 10-4 s-1) and high strain rates (3 × 103 s-1) are presented.

Arthington, M. R.; Siviour, C. R.; Petrinic, N.; Elliott, B. C. F.

2009-07-01

261

Neutron capture cross section of ^243Am  

NASA Astrophysics Data System (ADS)

The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for neutron capture cross section measurement on ^243Am. The high granularity of DANCE (160 BaF2 detectors in a 4? geometry) enables the efficient detection of prompt gamma-rays following neutron capture. DANCE is located on the 20.26 m neutron flight path 14 (FP14) at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The methods and techniques established in [1] were used for the determination of the ^243Am neutron capture cross section. The cross sections were obtained in the range of neutron energies from 0.02 eV to 400 keV. The resonance region was analyzed using SAMMY7 and resonance parameters were extracted. The results will be compared to existing evaluations and calculations. Work was performed under the auspices of the U.S. Department of Energy at Los Alamos National Laboratory by the Los Alamos National Security, LLC under Contract No. DE-AC52-06NA25396 and at Lawrence Livermore National Laboratory by the Lawrence Livermore National Security, LLC under Contract No. DE-AC52-07NA27344. [4pt] [1] M. Jandel et al., Phys. Rev. C78, 034609 (2008)

Jandel, M.

2009-10-01

262

(n,?) reactions cross section research at IPPE  

NASA Astrophysics Data System (ADS)

An experimental set-up based on an ionization chamber with a Frisch grid and wave form digitizer was used for (n,?) cross section measurements. Use of digital signal processing allowed us to select a gaseous cell inside the sensitive area of the ionization chamber and determine the target atoms in it with high accuracy. This kind of approach provided us with a powerful method to suppress background arising from the detector structure and parasitic reactions on the working gas components. This method is especially interesting to study neutron reactions with elements for which solid target preparation is difficult (noble gases for example). In the present experiments we used a set of working gases which contained admixtures of nitrogen, oxygen, neon, argon and boron. Fission of 238U was used as neutron flux monitor. The cross section of the (n,?) reaction for 16O, 14N, 20Ne, 36Ar, 40Ar and the yield ratio ?0/?1 of 10B(n,?0) to 10B(n,?1) reactions was measured for neutron energies between 1.5 and 7 MeV. Additionally a measurement of the 50Cr(n,?) cross section using a solid chromium target is also reported.

Khryachkov, V. A.; Bondarenko, I. P.; Kuzminov, B. D.; Semenova, N. N.; Sergachev, A. I.; Ivanova, T. A.; Giorginis, G.

2012-02-01

263

Neutron activation cross sections on lead isotopes  

NASA Astrophysics Data System (ADS)

The cross sections for the reactions Pb204(n,n'?)Pb204m, Pb204(n,2n)Pb203, Pb204(n,2n)Pb203m1, Pb204(n,3n)Pb202m, Pb206(n,3n)Pb204m, Pb206(n,?)Hg203, and Pb208(n,p)Tl208 were determined at the IRMM van de Graaff laboratory in the neutron energy range from 14 to 21 MeV. Both natural and enriched samples were irradiated with neutrons produced via the H3(d,n)He4 reaction. The induced activities were determined by gamma-ray spectrometry using a HPGe detector in a low-background shield. Neutron fluences were determined with the well-known cross section of the Al27(n,?)Na24 reaction. Enriched samples were essential to determine the cross sections for the reactions with Pb204m and Pb206m isomers in the final state. Accurate results for reactions with Pb204,206 as target nuclei with natural lead samples were enabled through a precise measurement of the isotopic ratios. For a first investigation of the consequences of the present data for nuclear reaction models they were confronted with calculations based on global parameter systematics in a phenomenological and in a microscopic approach and with parameters selected to reproduce the available data. The TALYS code was used for the former two calculations involving parameter systematics while the STAPRE code was used for the latter calculation.

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

2009-08-01

264

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

265

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.; Strifors, H.C. [National Defense Research Establishment, Stockholm (Sweden)

1996-09-01

266

Analysis of Perseid meteor head echo data collected using the Advanced Research Projects Agency Long-Range Tracking and Instrumentation Radar (ALTAIR)  

NASA Astrophysics Data System (ADS)

The 1998 Perseid meteor shower was observed using the Advanced Research Projects Agency (ARPA) Long-Range Tracking and Instrumentation Radar (ALTAIR) in order to study potential meteoroid impact on orbiting spacecraft. ALTAIR is a dual-frequency radar that operates at VHF and UHF, and its high sensitivity and precise calibration make it uniquely suited for detecting meteor head echoes. ALTAIR is dually polarized and records left-circularly and right-circularly polarized signal returns, which allow the determination of polarization ratios. ALTAIR uses a multihorn feed and interferometry to measure target angle of arrival. This paper contains analysis on Perseid data that were collected at VHF (158 MHz). Meteor head echo statistics are presented, including mean altitude, radial velocity, radar cross section (RCS), and polarization ratio. ALTAIR's VHF detection rate was approximately 1 head echo per second. An in-depth analysis on select head echoes to estimate meteor decelerations and densities has also been included.

Close, S.; Hunt, S. M.; Minardi, M. J.; McKeen, F. M.

2000-09-01

267

Actinide Targets for Neutron Cross Section Measurements  

SciTech Connect

The Advanced Fuel Cycle Initiative (AFCI) and the Generation IV Reactor Initiative have demonstrated a lack of detailed neutron cross-sections for certain "minor" actinides, those other than the most common (235U, 238U, and 239Pu). For some closed-fuel-cycle reactor designs more than 50% of reactivity will, at some point, be derived from "minor" actinides that currently have poorly known or in some cases not measured (n,?) and (n,f) cross sections. A program of measurements under AFCI has begun to correct this. One of the initial hurdles has been to produce well-characterized, highly isotopically enriched, and chemically pure actinide targets on thin backings. Using a combination of resurrected techniques and new developments, we have made a series of targets including highly enriched 239Pu, 240Pu, and 242Pu. Thus far, we have electrodeposited these actinide targets. In the future, we plan to study reductive distillation to achieve homogeneous, adherent targets on thin metal foils and polymer backings. As we move forward, separated isotopes become scarcer, and safety concerns become greater. The chemical purification and electodeposition techniques will be described.

John D. Baker; Christopher A. McGrath

2006-10-01

268

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

269

Cross-section measurements for radioactive samples  

SciTech Connect

The measurement of (n,p), (n,..cap alpha..) and (n,..gamma..) cross sections for radioactive nuclei is of interest to both nuclear physics and astrophysics. For example, using these reactions, properties of levels in nuclei at high excitation energies, which are difficult or impossible to study using other reactions, can be investigated. Also, reaction rates for both big-bang and stellar nucleosynthesis can be obtained from these measurements. In the past, the large background associated with the sample activity limited these types of measurements to radioisotopes with very long half-lives. The advent of the low-energy, high-intensity neutron source at the Los Alamos Neutron Scattering CEnter (LANSCE) has greatly increased the number of nuclei which can be studied. Examples of (n,p) measurements on samples with half lives as short as fifty-three days will be given. The nuclear physics and astrophysics to be learned from these data will be discussed. Additional difficulties are encountered when making (n,..gamma..) rather than (n,p) or (n,..cap alpha..) measurements. However, with a properly-designed detector, and the high peak neutron intensities now available, (n,..gamma..) measurements can be made for nuclei with half lives as short as several months. Progress on the Los Alamos (n,..gamma..) cross-section measurement program for radioactive samples will be discussed. 39 refs., 7 figs.

Koehler, P.E.; O'Brien, H.A.

1988-01-01

270

Absorption cross section of absorber cylinders  

NASA Astrophysics Data System (ADS)

The paper covers derivation and calculation of absorption and scattering cross sections of three types of cylinders made out of porous absorber material. These types are, respectively, (a) completely bulk reacting (homogeneous and isotropic), (b) axially locally reacting but bulk reacting about the circumference (rigid partitions inserted normal to the cylinder's axis), and (c) locally reacting in all directions. The sound field may be either plane waves with oblique incidence or diffuse sound fields. The characteristic data used for the absorber materials, propagation constant and wave impedance, are in the form of simple approximations taken from a model theory of fibrous absorbers for low frequencies, with experimental data being used at medium and high frequencies. A formulation of the scattered sound field in series of Bessel function is used. The numerical results show the influence of the frequency, the diameter, the materials' flow resistance and the angle of incidence. Maps are plotted of lines of constant absorption cross-sections for the different types of cylinders and sound fields, revealing the dependence upon these parameters. Acoustical phenomena of the sound absorption by absorber cylinders are discussed, such as resonance scattering, surface waves, frequency ranges with small angular dependence and parameter combinations with only small frequency dependence of the absorption. Such cylinders would be appropriate as calibration objects in round robin tests of sound absorption measurement in reverberant rooms.

Mechel, F. P.

1986-05-01

271

Neutronic Cross Section Calculations on Fluorine Nucleus  

NASA Astrophysics Data System (ADS)

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

Kara, A.; Tel, E.

2013-06-01

272

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...

273

Microscopic optical-model calculations of neutron total cross sections and cross section differences  

Microsoft Academic Search

Using the microscopic optical model of Jeukenne, Lejeune, and Mahaux we have calculated the absolute neutron total cross sections and cross section differences of ¹⁴°Ce, ¹³⁹La--¹⁴°Ce, ¹⁴¹Pr--¹⁴°Ce, ¹⁴²Ce--¹⁴°Ce, and ⁴°Ca, ⁴⁴Ca--⁴°Ca from 6--60 MeV and have made comparisons with experimental data. Except for ¹⁴²Ce--¹⁴°Ce, reasonable agreement with the mass 140 data was achieved with proton densities rho\\/sub p\\/ of the

H. S. Camarda; F. S. Dietrich; T. W. Phillips

1989-01-01

274

Electron cross section set for CHF{sub 3}  

SciTech Connect

We describe the development of a consistent set of low-energy electron collision cross sections for trifluoromethane, CHF{sub 3}. First-principles calculations are used to obtain key elastic and inelastic cross sections. These are combined with literature values of the ionization cross section and with vibrational excitation cross sections obtained from the Born approximation to form a preliminary set, which is then adjusted to achieve consistency with measured swarm parameters. {copyright} 2001 American Institute of Physics.

Morgan, W. Lowell; Winstead, Carl; McKoy, Vincent

2001-08-15

275

Photoneutron cross sections of 58Ni and 60Ni  

Microsoft Academic Search

Photoneutron cross sections of 58Ni and 60Ni have been measured, using separated isotopes and nearly monoenergetic photons from in-flight annihilation of positrons. Both (gamma,n) and (gamma,2n) cross sections have been obtained; the (gamma,3n) cross section for both isotopes was found to be essentially negligible up to the highest energy measured, 33.5 MeV. The peak cross section of 27 mb for

S. C. Fultz; R. A. Alvarez; B. L. Berman; P. Meyer

1974-01-01

276

Evaluation of Kerma in Carbon and the Carbon Cross Sections.  

National Technical Information Service (NTIS)

A preliminary simultaneous least squares fit to measurements of kerma in carbon, and carbon cross sections taken from the ENDF/B-V file was carried out. In the calculation the shapes of the total cross section and the various partial cross sections were r...

E. J. Axton

1992-01-01

277

Reanalysis of the e+e-??? reaction cross section  

Microsoft Academic Search

resonance, in order to make a right choice of the minimization solution. In this work the ?'-meson parameters were estimated from the experimental data on the e+e? ? ?? cross section (2, 3). The cross section value in the ?'-resonance maximum obtained from the approximation of the e+e? ? ?? cross section can be translated to the e+e? ? ?'

M. N. Achasov; K. I. Beloborodov; A. V. Berdyugin; A. G. Bogdanchikov; A. D. Bukin; D. A. Bukin; T. V. Dimova; V. P. Druzhinin; V. B. Golubev; A. A. Korol; S. V. Koshuba; E. V. Pakhtusova; S. I. Serednyakov; Z. K. Silagadze; A. V. Vasiljev

2007-01-01

278

EVALUATION OF CROSS SECTIONS FOR Cm242, -243, -244  

Microsoft Academic Search

The work is devoted to the analysis of available experimental and evaluated data on the neutron cross sections for Cm-242, Cm-243, Cm-244. A comparison of experimental data with the results of theoretical calculations and the evaluations of the most important cross sections were performed. As a result the new version of complete files of evaluated neutron cross sections for Cm-242,

A. I. Blokhin; A. S. Badikov; A. V. Ignatyuk; V. P. Lunev; V. N. Manokhin; G. Ya; K. I. Zolotarev

279

Nuclear Cross Sections for 900 MeV Protons  

Microsoft Academic Search

The cross sections of carbon, aluminium, copper, antimony and lead for 900 MeV protons have been measured. Observations were made with a counter telescope in which the final counter subtended a number of different angles at the absorber. Extrapolation of `poor geometry' results gave the inelastic cross sections. Extrapolations for nuclear cross sections, which require `good geometry' measurements, were possible

N. E. Booth; B. Ledley; D. Walker; D. H. White

1957-01-01

280

Why understanding neutrino cross sections is important for astrophysics  

SciTech Connect

Neutrino cross sections are important in many different astrophysical environments. Particularly needed is information about low energy (tens of MeV) cross sections. We review, for a few situations, the importance of neutrino cross sections for supernovae, gamma ray bursts and neutron stars.

McLaughlin, G. C. [Department of Physics North Carolina State University, Raleigh, NC 27695-8202 (United States)

2007-12-21

281

Neutron Fission of 235,237,239U and 241,243Pu: Cross Sections, Integral Cross Sections and Cross Sections on Excited States  

Microsoft Academic Search

In a recent paper submitted to Phys. Rev. C they have presented estimates for (n,f) cross sections on a series of Thorium, Uranium and Plutonium isotopes over the range E{sub n} = 0.1-2.5 MeV. The (n,f) cross sections for many of these isotopes are difficult or impossible to measure in the laboratory. The cross sections were obtained from previous (t,pf)

W Younes; H C Britt

2003-01-01

282

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

283

Top cross section measurement at CDF  

SciTech Connect

This paper describes the latest measurements of the t{bar t} pair production cross section performed by the CDF Collaboration analyzing p{bar p} collisions at a center-of-mass energy of 1.96 TeV from Fermilab Tevatron, as presented at the XVIII International Workshop on Deep-Inelastic Scattering and Related Subjects. In order to test Standard Model predictions, several analysis methods are explored and all the top decay channels are considered, to better constrain the properties of the top quark and to search for possible sources of new physics affecting the pair production mechanism. Experimental results using an integrated luminosity up to 5.1 fb{sup -1} are presented.

Compostella, Gabriele; /INFN, CNAF /Padua U.

2010-01-01

284

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

285

Dielectronic recombination cross sections of neonlike xenon  

SciTech Connect

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

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

1992-03-16

286

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

SciTech Connect

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

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

1980-06-01

287

A component model approach for the RCS validation of an electrically large open-ended cylindrical cavity  

Microsoft Academic Search

A novel RCS component prediction model approach to producing both fast and accurate scattering from an electrically large open-ended cylindrical cavity (circular cross section) is presented. The component model is a hybrid approach which easily permits individual scattering mechanisms to be coherently combined to produce a high fidelity signature. For this problem, the component model included scattering produced from the

Audrey J. Dumanian; Earl C. Burt; Brandon A. Kemp

2007-01-01

288

RCS REDUCTION BY USING RANDOM SCATTERERS  

Microsoft Academic Search

Abstract—A useful method,for monostatic RCS reduction of unavoidable shapes in desired frequency bandwidth and angle range is proposed. The proposed method is based on the concept of the random scatterer for RCS reduction and the genetic algorithm for optimization. PO, MEC, and SBR methods are used to obtain RCS. Target shapes whose RCS we want to reduce are basically a

T.-I. Suh; S.-H. Suk; H.-S. Park; J.-K. Bang; H.-T. Kim

2003-01-01

289

FREE ANTINEUTRINO ABSORPTION CROSS SECTION. II. EXPECTED CROSS SECTION FROM MEASUREMENTS OF FISSION FRAGMENT ELECTRON SPECTRUM  

Microsoft Academic Search

A measurement of the electron spectrum from the thermal neutron fission ; of U²³⁵ is described. From this spectrum the antineutrino spectrum is ; calculated, and on the basis of the two-component theory of the antineutrino a ; predicted average cross section for the absorption of antineutrinos by protons is ; (6.1 the J-57 engin 1) x 10⁻⁴³ cm²fission. This

R. E. Carter; F. Reines; J. J. Wagner; M. E. Wyman

1959-01-01

290

Measurements of neutron cross sections and isomeric cross section ratios in Se isotopes  

Microsoft Academic Search

The activation cross sections of 14.7 MeV neutron-induced reactions have been measured in Se isotopes. The experimental results have been compared with the predictions of the statistical theory of the compound nucleus. For some reactions it has been possible to determine the isomeric ratios; these ratios have been analysed using the statistical calculation of Huizenga and Vandenbosch, and estimates have

B. Minetti; A. Pasquarelli

1967-01-01

291

APPARATUS FOR MEASURING TOTAL NEUTRON CROSS SECTIONS  

DOEpatents

An apparatus is described for measuring high-resolution total neutron cross sections at high counting rate in the range above 50-kev neutron energy. The pulsed-beam time-of-flight technique is used to identify the neutrons of interest which are produced in the target of an electrostatic accelerator. Energy modulation of the accelerator . makes it possible to make observations at 100 energy points simultaneously. 761O An apparatus is described for monitoring the proton resonance of a liquid which is particulariy useful in the continuous purity analysis of heavy water. A hollow shell with parallel sides defines a meander chamber positioned within a uniform magnetic fieid. The liquid passes through an inlet at the outer edge of the chamber and through a spiral channel to the central region of the chamber where an outlet tube extends into the chamber perpendicular to the magnetic field. The radiofrequency energy for the monitor is coupled to a coil positioned coaxially with the outlet tube at its entrance point within the chamber. The improvement lies in the compact mechanical arrangement of the monitor unit whereby the liquid under analysis is subjected to the same magnetic field in the storage and sensing areas, and the entire unit is shielded from external electrostatic influences.

Cranberg, L.

1959-10-13

292

Fragmentation cross sections of protonated water clusters  

NASA Astrophysics Data System (ADS)

We have measured fragmentation cross sections of protonated water cluster cations (H2O)n=30-50H+ by collision with water molecules. The clusters have well-defined sizes and internal energies. The collision energy has been varied from 0.5 to 300 eV. We also performed the same measurements on deuterated water clusters (D2O)n=5-45D+ colliding with deuterated water molecules. The main fragmentation channel is shown to be a sequential thermal evaporation of single molecules following an initial transfer of relative kinetic energy into internal energy of the cluster. Unexpectedly, that initial transfer is very low on average, of the order of 1% of collision energy. We evaluate that for direct collisions (i.e., within the hard sphere radius), the probability for observing no fragmentation at all is more than 35%, independently of cluster size and collision energy, over our range of study. Such an effect is well known at higher energies, where it is attributed to electronic effects, but has been reported only in a theoretical study of the collision of helium atoms with sodium clusters in that energy range, where only vibrational excitation occurs.

Zamith, Sébastien; Labastie, Pierre; L'Hermite, Jean-Marc

2012-06-01

293

Total and partial photoneutron cross sections for Pb isotopes  

NASA Astrophysics Data System (ADS)

Using quasimonochromatic laser-Compton scattering ? rays, total photoneutron cross sections were measured for 206,207,208Pb near neutron threshold with a high-efficiency 4? neutron detector. Partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near threshold by measuring anisotropies in photoneutron emission with linearly polarized ? rays. The E1 strength dominates over the M1 strength in the neutron channel where E1 photoneutron cross sections show extra strength of the pygmy dipole resonance in 207,208Pb near the neutron threshold corresponding to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several ?N2 units of B(M1)? strength were observed in 207,208Pb just above neutron threshold, which correspond to an M1 cross section less than 10% of the total photoneutron cross section.

Kondo, T.; Utsunomiya, H.; Goriely, S.; Daoutidis, I.; Iwamoto, C.; Akimune, H.; Okamoto, A.; Yamagata, T.; Kamata, M.; Itoh, O.; Toyokawa, H.; Lui, Y.-W.; Harada, H.; Kitatani, F.; Hilaire, S.; Koning, A. J.

2012-07-01

294

Electron collisions with CO: Elastic and vibrational excitation cross sections  

SciTech Connect

Absolute differential elastic and vibrational excitation cross sections up to v=11 were measured for CO in scattering angle ranges extending to 180 deg. at energies between 0.2 and 5 eV (and an elastic measurement at 10 eV). The lowest angles were 0 deg. for inelastic scattering and between 5 deg. and 20 deg. for elastic scattering, depending on energy. Integral cross sections were derived by integrating under the angular distributions and compared with previous beam and swarm measurements. The sum of the integral cross sections agrees very well with the available transmission measurements of the grand total cross section, thus validating the present measurements. The present elastic differential and integral cross sections are in excellent agreement with the best available measurement [Gibson et al., J. Phys. B 29, 3197 (1996)], but the v=1 inelastic cross section is about 25% higher. This could have consequences for simulations of cometary and planetary atmospheres.

Allan, M. [Department of Chemistry, University of Fribourg, chemin du Musee 9, CH-1700 Fribourg (Switzerland)

2010-04-15

295

Determining the Uncertainty on the Total Heavy Flavor Cross Section  

SciTech Connect

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

Vogt, R

2008-07-22

296

Next-to-leading order cross sections for tagged reactions  

NASA Astrophysics Data System (ADS)

We extend the phase space slicing method of Giele, Glover and Kosower for performing next-to-leading order jet cross section calculations in two important ways: we show how to include fragmentation functions and how to include massive particles. These extensions allow the application of this method not just to jet cross sections but also to cross sections in which a particular final state particle, including a D or B meson, is tagged.

Keller, Stéphane; Laenen, Eric

1999-06-01

297

Scaling behavior of radiative recombination cross sections and rate coefficients  

Microsoft Academic Search

Direct radiative recombination (RR) cross sections Ï{sup RR} and rate coefficients α{sup RR} are presented for all ions using the scaling property of the cross section in the parameter η={ital Z}{sub eff}\\/({ital ka}â). The RR cross section is defined simply in terms of two parameters, η and the number of electrons {ital N} in the target ion. The RR rate

Daniel J. McLaughlin; Y. Hahn

1991-01-01

298

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

299

CROSS SECTION NEAR THE H LYMAN a LINE  

Microsoft Academic Search

Molecular oxygen photoabsorption cross sections have been measured at 0.2-A intervals between 1214.0 and 1218.6 A at temperatures of 294, 195, and 82 K. The measured pressure dependence of the cross sections is in satisfactory agreement with earlier observations, but the room temperature cross sections are found to be significantly different from previously reported high-resolution measurements in the Lyman a

J. H. Carver; H. P. Gies; T. I. Hobbs; B. R. Lewis; D. G. McCoy

1977-01-01

300

Measurements of beauty cross sections at the CMS experiment  

NASA Astrophysics Data System (ADS)

The CMS experiment at the Large Hadron Collider has recorded proton-proton collision data at a center of mass energy of 7 TeV during 2010. Several measurements have been made of production cross sections involving the b quark. The open beauty production cross section is presented as a function of muon transverse momentum and pseudorapidity. The mode B ->?D^0 X is studied. Also presented is a ?b integrated cross section measurement.

Bean, Alice

2011-04-01

301

Thermal Neutron Capture Cross Section of Carbon13  

Microsoft Academic Search

The thermal neutron capture cross section of C13 has been determined from the amount of C14 formed in pile-irradiated samples of graphite, barium carbonate, and carbon dioxide. Because of the impurity reaction, N14(n, p)C14, of comparatively high cross section, the results were consistent only when samples were used which were enriched in C13. The average isotopic cross section determined for

G. R. Hennig

1954-01-01

302

Charge exchange cross sections for the Io plasma torus  

SciTech Connect

An impact parameter method for calculating cross sections as a function of incident ion energy is used in conjunction with an improved exchange energy formulation to update several of the charge exchange cross sections currently used in Io plasma torus modeling. New cross sections for S{sup +} + S{sup 2+} {yields} S{sup 2} + S{sup +} and Na{sup +} on neutral targets, useful in analyzing the fast Na jets observed at Io, are also calculated.

McGrath, M.A.; Johnson, R.E. (Univ. of Virginia, Charlottesville (USA))

1989-03-01

303

Estimate of the cross section for thermal neutrons  

NASA Astrophysics Data System (ADS)

Cross section of the thermal neutrons is considered in the framework of the statistical approach to the complicated nuclei. The probability distribution ?( z = ?/?*) to have given cross section ? (determined by fluctuations of resonance positions and widths), where ?* is the cross section for the model of equidistant resonances with the same width, has been calculated. The last quantity can be represented in terms of the neutron strength function for given nuclei. The probability distribution ?( z) is universal for all nuclei.

Petrov, Yu.; Petrov, V.

2013-08-01

304

Scaling properties of proton-nucleus total reaction cross sections  

NASA Astrophysics Data System (ADS)

We study the scaling properties of proton-nucleus total reaction cross sections for stable nuclei and propose an approximate expression in proportion to Z2/3?pptotal+N2/3?pntotal. 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.

Abu-Ibrahim, Badawy; Kohama, Akihisa

2010-05-01

305

Energy dependence of proton-nucleus reaction cross sections  

NASA Astrophysics Data System (ADS)

Reaction-cross-section data for proton-nucleus scattering up to 1 GeV have been analyzed in a black-disk model. Simple phenomenological relations are derived, which make it possible to predict the energy dependence of proton-nucleus reaction cross sections. The relations require only the total cross sections in nucleon-nucleon scattering and the matter densities of the proton and the target nucleus.

Ingemarsson, A.; Lantz, M.

2005-12-01

306

A method for measuring light ion reaction cross-sections  

Microsoft Academic Search

An experimental procedure for measuring reaction cross-sections of light ions in the energy range 20–50MeV\\/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross-sections for five different sizes of the solid angle in steps from 99.1% to 99.8% of the total solid angle. The final reaction cross-section values are

R. F. Carlson; A. Ingemarsson; M. Lantz; G. J. Arendse; A. Auce; A. J. Cox; S. V. Förtsch; N. M. Jacobs; R. Johansson; J. Nyberg; J. Peavy; P.-U. Renberg; O. Sundberg; J. A. Stander; G. F. Steyn; G. Tibell; R. Zorro

2005-01-01

307

A cross-sectional ultrasound imaging for measuring body composition  

Microsoft Academic Search

We have developed a measuring system to visualize a complete cross-sectional image of the human extremity using ultrasonography. This system uses several ultrasound probes, and these probes measure fragmentary graphical images of one cross-sectional plane which are then transformed into a complete cross-sectional image. The developed system is superior to other imaging devices in many respects because it is portable,

Kiyotaka Fukumoto; Masayoshi Tsubai; Satoshi Muraki; Osamu Fukuda; Hironori Sato

2007-01-01

308

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

Microsoft Academic Search

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

H. D. Griffiths

2003-01-01

309

Partial Photoneutron Cross Sections for the Isomeric State Tam180  

NASA Astrophysics Data System (ADS)

Photoneutron cross sections for Ta181(?,n)Tam180 were determined from simultaneous measurements of total cross sections (?tot) and ground-state cross sections (?gs) for Ta180 in photodisintegration of Ta181 with laser Compton-backscattered ? rays. Techniques of direct neutron counting and photoactivation were used for the measurement of ?tot and ?gs, respectively. The partial cross sections for the isomeric state serves as a novel probe of the nuclear level density of Ta180. Implications for the p- and s-process nucleosynthesis of Tam180 are given.

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.

2006-05-01

310

Nucleon-Nucleon Cross Sections in Isospin Asymmetric Nuclear Matter  

NASA Astrophysics Data System (ADS)

The in medium nucleon-nucleon (NN) cross sections in isospin asymmetric nuclear matter at various densities are investigated in the framework of Brueckner-Hartree-Fock theory with the Bonn B two-body nucleon-nucleon interaction supplemented with a new version microscopic three-body force (TBF). The TBF depresses the amplitude of cross sections at high density region. At low densities, the proton-proton and neutron-neutron cross sections decrease while the proton-neutron one increases as the asymmetry increases. But the sensitivity of the NN cross sections to the isospin asymmetry are reduced with the increasing density.

Zhang, Hongfei; Dong, Jianmin; Zuo, Wei; Lombardo, Umberto

311

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

312

Derivation of reaction cross sections from experimental elastic backscattering probabilities  

NASA Astrophysics Data System (ADS)

The relationship between the backward elastic scattering probabilities and the reaction cross sections is derived. This is a very simple and useful method to extract reaction cross sections for heavy-ion systems. We compare the results of our method with those that use the traditional full elastic scattering angular distributions for several systems at energies near and above the Coulomb barrier. From the calculated reaction and capture cross sections that use the present method, we derive the cross sections of other mechanisms for weak nearly spherical systems.

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

2013-10-01

313

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

314

Neutron-capture cross sections from indirect measurements  

NASA Astrophysics Data System (ADS)

Cross sections for compound-nuclear reactions 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.

2012-02-01

315

14 MeV Neutrons SEU Cross Sections in Deep Submicron Devices Calculated Using Heavy Ion SEU Cross Sections  

Microsoft Academic Search

Ananalyticalmodelisdevelopedtocalculateneutron- induced SEU cross section in deep submicron devices from heavy ion SEU cross section. It is based on the energy spectra of the sec- ondaries of nuclear reactions which yields the LET dis- tribution of all secondary ions. The integration of this distribution function with the measured heavy ion cross section vs. LET yields then-SEUcrosssection.Tomakethecalculationsstraightforward, the neutron-induced LET distribution

Avner Haran; Joseph Barak; Leo Weissman; David David; Eitan Keren

2011-01-01

316

In-medium nucleon-nucleon cross section and its effect on total nuclear reaction cross section  

Microsoft Academic Search

A phenomenological formula for in-medium nucleon-nucleon cross section is presented, in which nuclear matter density and incident energy dependencies are included. This formula is used to study total nuclear reaction cross section based on Coulomb-modified Glauber model. The calculated results can reproduce experimental total reaction cross section induced by the stable nuclei and the exotic nuclei over a wide energy

Cai Xiangzhou; Feng Jun; Shen Wenqing; Ma Yugang; Wang Jiansong; Ye Wei

1998-01-01

317

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

Microsoft Academic Search

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

F. Cvelbar; A. Hudoklin; M. Potokar

1970-01-01

318

The synchrotron and cyclo-synchrotron absorption cross-section  

Microsoft Academic Search

The usefulness of the concept of a cross section for the synchrotron and the cyclosynchrotron absorption process is emphasized. It is shown that the previously known relation between the cross section and the single particle emissivity is most easily derived by applying the Einstein coefficients and their relations to a system with three energy levels. Using this relation and known

Gabriele Ghisellini; Roland Svensson

1991-01-01

319

Incoherent scattering cross sections for some ions of solar abundance  

SciTech Connect

Incoherent scattering cross sections are calculated in a relativistic formalism for a number of ions abundant in the solar atmosphere. It is argued that such cross sections are necessary for properly calculating Compton scattering and radiation transport in this or similar environments.

Kahane, Sylvian [Physics Department, Nuclear Research Center Negev, PO Box 9001, 84190 Beer Sheva (Israel)]. E-mail: skahane@bgu.ac.il

2007-03-15

320

A New Technique To Investigate Total Reaction Cross Sections  

SciTech Connect

We analyze the total reaction cross sections of several systems, especially weakly bound systems, by the use of a recently developed technique. We show a systematic behavior for the different systems, with larger reaction cross sections for systems with halo nuclei as projectiles.

Shorto, J. M. B.; Gomes, P. R. S.; Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Niteroi, 24210-340 (Brazil); Canto, L. F. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, CP 68528, Rio de Janeiro, 21941-972 (Brazil); Chamon, L. C. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, Sao Paulo, 05315-970 (Brazil)

2010-08-04

321

Criteria for the selection of dosimetry cross sections.  

SciTech Connect

This paper defines a process for selecting dosimetry-quality cross sections. The recommended cross-section evaluation depends on screening high-quality evaluations with quantified uncertainties, down-selecting based on comparison to experiments in standard neutron fields, and consistency checking in reference neutron fields. This procedure is illustrated for the {sup 23}Na(n,{gamma}){sup 24}Na reaction.

Griffin, Patrick Joseph

2003-07-01

322

Extraction of Asymptotic Nucleon Cross Sections from Deuterium Data.  

National Technical Information Service (NTIS)

The effect of Fermi motion on the extraction of asymptotic total neutron cross sections from deuterium data is examined in some detail. Particular attention is paid to the threshold condition on the nucleon cross sections. Using realistic hard-core wave f...

W. B. Atwood G. B. West

1972-01-01

323

Optimizing waveguide cross sections with respect to power handling capability  

Microsoft Academic Search

The problem of optimizing power transmission through uniform perfectly conducting waveguides of double symmetric cross section is discussed. Using an efficiency factor specifically created for single-mode propagation in uniform waveguides, the authors previously developed a unique method of geometric parametrization that determines the waveguide cross-sectional size and shape resulting in maximum power transmission between a source and receiver. Here they

Charles S. Kenney; P. L. Overfelt

1992-01-01

324

Total Nuclear Photoabsorption Cross Sections and the Levinger's Factor.  

National Technical Information Service (NTIS)

The Mainz group data on total photoabsorption cross sections of lithium, beryllium, carbon, oxygen, aluminium and calcium, in the energy range 40-150 MeV, are analysed. It is shown that the available cross section data provide physical evidence for an inc...

O. A. P. Tavares J. D. Pinheiro Filho

1979-01-01

325

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. Supported by the Swiss National Science Foundation.

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

326

Scattering from parallel metallic cylinders with arbitrary cross sections  

Microsoft Academic Search

The integral equations for scattering by a set of parallel metallic cylinders, each cylinder of arbitrary cross section, are solved directly by means of a digital computer program giving the current distribution induced on the scatterer surfaces, the scattering cross section vs azimuthal angle, and the induced field ratio (IFR) for both parallel and perpendicularly polarized incident waves. The present

MOGENS G. ANDREASEN

1964-01-01

327

First measurement of the charged current cross section at HERA  

Microsoft Academic Search

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

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

1994-01-01

328

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

329

Benchmark Calculations of Electron-Impact Differential Cross Sections  

SciTech Connect

The calculation of electron-atom excitation and ionization cross section is considered in both the non-relativistic and relativistic scattering theory. We consider electron collisions with H, He, Cs, and Hg. Differential cross sections for elastic scattering and ionization are presented.

Bray, I.; Bostock, C. J.; Fursa, D. V.; Hines, C. W.; Kadyrov, A. S.; Stelbovics, A. T. [ARC Centre for Antimatter-Matter Studies, Curtin University, GPO Box U1987 Perth, Western Australia 6845 (Australia)

2011-05-11

330

FISSION-NEUTRON CROSS SECTIONS FOR THRESHOLD REACTIONS  

Microsoft Academic Search

Data are presented on fission neutron activation by the (n,p), (n,k ; alpha ), and (n,2n) reacticns. Half lives, cross sections, and gamma-ray ; energies are tabulated for various reactions. Cross sections for these reactions ; are needed for calculating activation levels of reactor coolants and components. ; (J.H.M.);

Rochlin

1959-01-01

331

SOME RECENT RESULTS ON FAST NEUTRON CROSS SECTIONS  

Microsoft Academic Search

A summary of recent neutron cross section work by several groups at Los ; Alamos in the energy range 0.1 to 16 Mev is presented. Calculated aed ; experimental data are presented for the dlfferential elastic scattering cross ; sections of C, Al, Fe, Ca, Sn, Pb, and U for 14.5Mev neutrons. Angular ; distributions of the inelastic neutrons emitted

Coon; J. H. comp

1958-01-01

332

Status of the Neutron Cross-Section Standards Database  

Microsoft Academic Search

A new evaluation of the neutron cross-section standards is now underway. This evaluation has been supported by the Working Party on International Evaluation Cooperation (WPEC), the Cross Section Evaluation Working Group (CSEWG), and an International Atomic Energy Agency Coordinated Research Program (CRP). The CRP has had the dominant role in producing these evaluations. An important goal is to produce the

Franz-Josef Hambsch; Allan D. Carlson; Herbert Vonach

2005-01-01

333

Neutron cross sections and their uncertainties obtained from nuclear systematics  

Microsoft Academic Search

Previously, neutron cross sections in the MeV range for nuclei ranging in Z from 21 through 41 were calculated using a hybrid empirical-statistical model code THRESH. The formalism includes level density, Coulomb barrier, and competing reaction effects and has been useful in the prediction of unmeasured cross sections or normalized to point measurements to generate complete excitation curves. Reaction data

Pearlstein

1975-01-01

334

Isolated photon cross section measurement at D0  

SciTech Connect

We report a new measurement of the isolated photon cross section by the D0 experiment at Fermilab using 326 pb{sup -1} of data from Run II of the Tevatron. The measured cross section agrees with the theoretical predictions within uncertainties.

Kumar, Ashish; /SUNY, Buffalo

2006-05-01

335

Nuclear Cross Sections and the Size of the Nucleus  

Microsoft Academic Search

The recent experiments on the total inelastic cross sections for 190-Mev deuterons on various target nuclei demand a considerably larger nuclear radius than is usually accepted to explain the experimental results. It is shown that this result is not inconsistent with the total nuclear cross sections for 90-Mev neutrons if a nonsquare-well nuclear shape is taken. Taking for numerical simplicity

Warren Heckrotte

1954-01-01

336

Neutron Capture Cross Sections: From Theory to Experiments and Back  

SciTech Connect

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

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

2005-05-24

337

Analysis and Interpretation of Stream Channel Cross-Sectional Data  

Microsoft Academic Search

Stream channel cross-sectional transects can be used to evaluate effects of management on stream channel morphology and therefore on fish habitat quality. We describe four indices that summarize raw data from stream channel cross sections to detect change in channel morphology over time, The net percent change in area under the transect quantifies net degradation or aggradation. The absolute percent

K. M. Olson-Rutz; C. B. Marlow

1992-01-01

338

Cross Section Evaluations for EnDF/B-vii.  

National Technical Information Service (NTIS)

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 ...

M. Herman D. Rochman P. Oblozinsky

2006-01-01

339

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

340

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

341

Absolute electron scattering cross sections for the CF2 radical.  

PubMed

Using a crossed electron-molecular beam experiment, featuring a skimmed nozzle beam with pyrolytic radical production, absolute elastic cross sections for electron scattering from the CF2 molecule have been measured. A new technique for placing measured cross sections on an absolute scale is used for molecular beams produced as skimmed supersonic jets. Absolute differential cross sections for CF2 are reported for incident electron energies of 30-50 eV and over an angular range of 20-135 deg. Integral cross sections are subsequently derived from those data. The present data are compared to new theoretical predictions for the differential and integral scattering cross sections, as calculated with the Schwinger multichannel variational method using the static-exchange and static-exchange plus polarization approximations. PMID:18352469

Maddern, Todd M; Hargreaves, Leigh R; Francis-Staite, Jessica R; Brunger, Michael J; Buckman, Stephen J; Winstead, Carl; McKoy, Vincent

2008-02-14

342

Theoretical cross sections for keV antiprotons  

NASA Astrophysics Data System (ADS)

Partial and total close-coupled semiclassical (impact parameter) cross sections and total classical Monte-Carlo cross sections for interactions inbar p + Ps andbar p, p+H collisions are computed in the intermediate keV range for antiprotons,bar p, up to 100 keV lab. Total cross sections for antihydrogen,bar H, formation are found to be large, 10-20×10-16 cm2 in a wider energy range than was anticipated earlier, up to some 20 keV lab. New estimates of cross sections for ionisation of atomic hydrogen by antiproton impact are reported for the low-energy range 1 30 keV lab where they are 10-20×10-17 cm2, being much larger than the corresponding cross sections for ionisation of hydrogen by proton impact. Data for excitation of H bybar p impact is also presented.

Ermolaev, A. M.

1989-03-01

343

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

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

2010-01-01

344

Study on Effective Average (?, n) Cross Section for Y, Zr, Nb, and Cs and (?, 3n) Cross Section for Tc  

Microsoft Academic Search

A nondestructive detection technique was proposed for the easy assessment of long-lived radionuclides by the use of bremsstrahlung photons. The nuclide of Tc was considered for the assessment over an effective average Tc (?, 3n) Tc cross section. For validating the experimental method on Tc, photonuclear (?, n) cross sections of Y, Zr, Nb, and Cs were measured. Continuous-energy bremsstralung

Kunio KATO; Hidehiko ARIMA; Nobuhiro SHIGYO; Kenji ISHIBASHI; Jun-ichi HORI; Ken NAKAJIMA

2010-01-01

345

Total Cross Sections for Positrons Scattered Elastically from Helium Based on New Measurements of Total Ionization Cross Sections.  

National Technical Information Service (NTIS)

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 present...

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

1990-01-01

346

Thermal neutron capture cross sections of the palladium isotopes  

NASA Astrophysics Data System (ADS)

Precise thermal neutron capture ?-ray cross sections ?? were measured for all elements with Z=1-83,90, and 92, except for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the ground state, ?0=???(GS) if the decay scheme is complete. The EGAF file contains partial ?-ray cross sections for all stable palladium isotopes. None of these decay schemes are complete, although in each case transitions de-exciting low-lying levels are known. We have performed Monte Carlo simulations of the palladium thermal neutron capture decay schemes using the computer code DICEBOX. The simulated populations of low low-lying levels are normalized to the measured ?? values from EGAF and the total radiative neutron cross section ?0 is obtained. The ?0 values derived for the palladium isotopes agree well with previous measurements and were in several cases more precise. Complementary use of ?-ray cross-section data and Monte Carlo calculations has proven effective in determining both the palladium total radiative cross sections and new nuclear structure information.

Krti?ka, M.; Firestone, R. B.; McNabb, D. P.; Sleaford, B.; Agvaanluvsan, U.; Belgya, T.; Revay, Z. S.

2008-05-01

347

Evaluation of kerma in carbon and the carbon cross sections  

SciTech Connect

A preliminary simultaneous least squares fit to measurements of kerma in carbon, and carbon cross sections taken from the ENDF/B-V file was carried out. In the calculation the shapes of the total cross section and the various partial cross sections were rigid but their absolute values were allowed to float in the fit within the constraints of the ENDF/B-V uncertainties. The construction of the ENDF/B-V file imposed improbable shapes, particularly in the case of the (12)C(n,n'3(alpha)) reaction, which were incompatible with direct measurements of kerma and of the reaction cross sections. Consequently a new evaluation of the cross section data became necessary. Since the available time was limited the new evaluation concentrated particularly on those aspects of the ENDF/B-V carbon file which would have most impact on kerma calculations. Following the new evaluation of cross sections new tables of kerma factors were produced. Finally, the simultaneous least squares fit to measurements of kerma and the new cross section file was repeated.

Axton, E.J.

1992-02-01

348

Thermal neutron capture cross sections of the palladium isotopes  

SciTech Connect

Precise thermal neutron capture {gamma}-ray cross sections {sigma}{sub {gamma}} were measured for all elements with Z=1-83,90, and 92, for He and Pm, at the Budapest Reactor. These data were evaluated with additional information from the literature to generate the Evaluated Gamma-ray Activation File (EGAF). Isotopic radiative neutron cross sections can be deduced from the total transition cross section feeding the ground state, {sigma}{sub 0}={sigma}{sigma}{sub {gamma}}(GS) if the decay scheme is complete. The EGAF file contains partial {gamma}-ray cross sections for all stable palladium isotopes. None of these decay schemes are complete, although in each case transitions de-exciting low-lying levels are known. We have performed Monte Carlo simulations of the palladium thermal neutron capture decay schemes using the computer code DICEBOX. The simulated populations of low low-lying levels are normalized to the measured {sigma}{sub {gamma}} values from EGAF and the total radiative neutron cross section {sigma}{sub 0} is obtained. The {sigma}{sub 0} values derived for the palladium isotopes agree well with previous measurements and were in several cases more precise. Complementary use of {gamma}-ray cross-section data and Monte Carlo calculations has proven effective in determining both the palladium total radiative cross sections and new nuclear structure information.

Krticka, M. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, CZ-180 00 Prague 8 (Czech Republic); North Carolina State University, Raleigh, NC 27695 (United States); Firestone, R. B. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); McNabb, D. P.; Sleaford, B.; Agvaanluvsan, U. [Lawrence Livermore National Laboratory, L-414, 7000 East Avenue, Livermore, CA 94551 (United States); Belgya, T.; Revay, Z. S. [Institute of Isotope and Surface Chemistry, H-1525, Budapest (Hungary)

2008-05-15

349

Fission cross sections in the intermediate energy region  

SciTech Connect

Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for {sup 235}U and {sup 238}U compared to intranuclear cascade and statistical model predictions.

Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J. (Los Alamos National Lab., NM (USA)); Carlson, A.D.; Wasson, O.A. (National Inst. of Standards and Technology, Gaithersburg, MD (USA)); Hill, N.W. (Oak Ridge National Lab., TN (USA))

1991-01-01

350

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

351

Relative charge transfer cross section from Rb(4d)  

SciTech Connect

Relative charge transfer cross section measurements for the excited state Rb(4d) with 7 keV Na{sup +} is reported. The specific channels reported are Na{sup +}+Rb(4d{sub 5/2}){yields}Na(nl)+Rb{sup +}, where the dominant transfer cross sections channels were nl=3d and 4s. Using a combination of a magneto-optical trap and recoil ion momentum spectroscopy (MOTRIMS methodology), the cross sections were measured relative to the previously studied Na{sup +}+Rb(5s,5p) systems at the same collision energy.

Shah, M.H.; Camp, H.A.; Trachy, M.L.; De Paola, B.D. [J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Flechard, X. [LPC CAEN, Boulevard du Marechal Juin, 14050 CAEN CEDEX (France); Gearba, M.A. [Department of Physics and Astronomy, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (United States); Nguyen, H. [Department of Physics and Astronomy, University of Wisconsin-Stevens Point, Stevens Point, Wisconsin 55481 (United States); Bredy, R. [Laboratoire de Spectrometrie Ionique et Moleculaire, Universite Claude Bernard Lyon1, 69622 Villeurbanne Cedex (France); Lundeen, S.R. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

2005-08-15

352

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

353

Elastic and Nonelastic Neutron Cross Sections for Beryllium  

Microsoft Academic Search

A time-of-flight technique has been used to measure angular distributions for the elastic scattering of neutrons from beryllium in the energy range from 2.6 to 6.0 Mev. Total neutron cross sections were also measured and the following nonelastic (total minus elastic) cross sections obtained: 2.60 Mev (0.27+\\/-0.13 barn), 3.50 (0.43+\\/-0.10), 4.10 (0.51+\\/-0.08), 5.00 (0.60+\\/-0.08), and 6.00 (0.73+\\/-0.07). Differential cross sections

J. B. Marion; J. S. Levin; L. Cranberg

1959-01-01

354

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

355

Graphical displays of cross sections produced on the computer  

SciTech Connect

Much time is devoted to manually constructing cross sections and interpreting geologic data. Computer-generated displays can save manual effort and provide an interpretive aid for the geologist. This poster session will display computer-generated cross sections containing full curve logs, lithology, oil and gas shows, geologic markers, interpreted dipmeters, and structural relationships. Contouring and the use of color will also be demonstrated as interpretive aids. Two of the methods used in preparing geologic data - the polynominal regression and the Markov process - will also be demonstrated. The poster session summarized the various ways in which the computer may display and aid in the interpretation of cross sections.

Brooks, L.L.

1985-02-01

356

Antinucleus-Nucleus Cross Sections Implemented in Geant4  

SciTech Connect

Cross sections of antinucleus ({bar p}, {bar d}, {bar t}, {sup 3}{ovr He}, {sup 4}{ovr He}) interactions with nuclei in the energy range 100 MeV/c to 1000 GeV/c per antinucleon are calculated in the Glauber approximation which provides good description of all known {bar p}Across sections. The results were obtained using a new parameterization of the total and elastic {bar p}p cross sections. Simple parameterizations of the antinucleus-nucleus cross sections are proposed for use in estimating the efficiency of antinucleus detection and tracking in cosmic rays and accelerator experiments. These parameterizations are implemented in the Geant4 toolkit.

Uzhinsky, V.; /CERN /Dubna, JINR; Apostolakis, J.; /CERN; Galoyan, A.; /Dubna, JINR; Folger, G.; /CERN; Grichine, V.M.; /Lebedev Inst.; Ivanchenko, V.N.; /CERN /Lomonosov Moscow State U.; Wright, D.H.; /SLAC

2012-04-26

357

Parameterized total cross sections for pion production in nuclear collisions  

NASA Astrophysics Data System (ADS)

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

Norbury, John W.; Townsend, Lawrence W.

2007-01-01

358

Two-frequency meteor observations using the Advanced Research Project Agency Long Range Tracking and Instrumentation Radar (ALTAIR)  

NASA Astrophysics Data System (ADS)

We present a sample of radar meteors observed during the November 1998 Leonid shower using the Advanced Research Project Agency (ARPA) Long Range Tracking and Instrumentation Radar (ALTAIR). Approximately 29 minutes of VHF data which produced over 900 VHF head echoes and 17 minutes of simultaneous UHF data were collected, which resulted in over 500 head echo detections. These data were analyzed to determine frequency-dependent radar cross section (RCS) characteristics [Close]. The techniques outlined here for determining meteor velocity from ALTAIR data produced a meteor distribution with a peak number of meteors at 56 km/s, consistent with viewing the Northern Apex meteor source. The angle between the radar line of sight and geomagnetic field shows a strong correlation with the radar's ability to detect nonspecular meteor trails. In addition, the range, azimuth and elevation angle data were used to compute the 3-d velocity of the head echoes. The first head echo that was detected using three frequencies (160, 422, and 1320 MHz) is also discussed.

Hunt, S.; Close, S.; Oppenheim, M.; Dyrud, L.

2001-11-01

359

Are RCS energy audits valid  

Microsoft Academic Search

The major goal of the federal Residential Conservation Service (RCS) is to improve the energy efficiency of existing homes (US Department of Energy, 1982). Its main feature is an on-site home energy audit (Oak Ridge National Laboratory, 1983). Information collected during the audit is combined with engineering calculations to develop recommendations to the household on conservation practices and measures to

E. Hirst; R. Goeltz

1984-01-01

360

Simulation of complex target RCS with application to SAR image recognition  

Microsoft Academic Search

SAR(synthetic aperture radar) image understanding and interpretation is essential for remote sensing of earth environment and target detection. In development of aided target recognition and identification system, SAR image database with rich information content plays important role is essential. This paper presents a RCS computation for simulation of orbital SAR image. After demodulation, the received SAR signal is given as

Cheng-Yen Chiang; Kun-Shan Chen

2011-01-01

361

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

362

56. CROSS SECTION OF POWERHOUSE, PROJECT 1933, EXHIBIT F, SANTA ...  

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

56. CROSS SECTION OF POWERHOUSE, PROJECT 1933, EXHIBIT F, SANTA ANA POWERHOUSE NO. 1. SCE drawing no. 5206856 (no date; FERC no. 1933-46). - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

363

Advanced Buckling Analyses of BEAMS with Arbitrary Cross Sections.  

National Technical Information Service (NTIS)

A computer program was developed to study distorsion of the cross section during buckling and the interaction between buckling modes, based on the combination of the spline finite strip method and Koiter's general theory of stability. A theory was develop...

G. M. Vanerp

1989-01-01

364

28. CROSS SECTION OF A RECTANGULAR COKE OVEN SHOWING THE ...  

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

28. CROSS SECTION OF A RECTANGULAR COKE OVEN SHOWING THE INTERNAL STRUCTURE OF THE OVEN. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

365

New Kr Cross Sections and Astrophysical Constraints on Presolar Grains  

SciTech Connect

A series of neutron-capture cross-section measurements on various krypton isotopes has been performed at the Geel Electron Linear Accelerator (GELINA). The total cross section of 84Kr and the capture cross section of 86Kr and 82Kr have been measured in the energy range from 0 up to 400 keV. Moreover, capture cross-section data for 80Kr and 83Kr have been obtained for a limited energy range, namely from 0 up to 5 keV, from a natural krypton sample. The main goal of the measurement campaign was to provide reliable nuclear data for s-process nucleosynthesis calculation. We performed a series of calculations for stars with mass from M = 1.5M{center_dot} to M = 3M{center_dot} and metallicity from solar down to 1/6 of solar with the aim to reproduce the krypton isotopic ratios found in silicon-carbide grains.

Mutti, P. [Institute Laue-Langevin, B.P.156 - 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Beer, H. [Forschungszentrum Karlsruhe, Institut fuer Kernphysik, P. O. Box 3640, 76021 Karlsruhe (Germany); Brusegan, A.; Corvi, F. [EC-JRC, Institute for Reference Materials and Measurements, Retieseweg, B-2440 Geel (Belgium); Gallino, R. [Dipartimento di Fisica Generale, Universita di Torino, v. Pietro Giuria 1, 10100 Turin (Italy)

2005-05-24

366

Cross Sections for Producing Some Light-Noble-Gas Nuclides  

NASA Astrophysics Data System (ADS)

Cross sections for making 3He, 20Ne, 21Ne, and 22Ne (including 3H and 22Na decay) from major target elements were compiled and evaluated for proton reactions and, for Ne isotopes from Mg, for neutron reactions.

Reedy, R. C.

2008-03-01

367

XCOM: Photon Cross Sections on a Personal Computer,  

National Technical Information Service (NTIS)

A computer program and data base are presented which can be used to calculate, with a personal computer, photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, in any element, compoun...

M. J. Berger J. H. Hubbell

1987-01-01

368

36. CROSS SECTIONAL VIEW OF ORIGINAL HORSE MESA DAM POWER ...  

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

36. CROSS SECTIONAL VIEW OF ORIGINAL HORSE MESA DAM POWER PLANT, LOOKING NORTH. ONLY TWO OF THE THREE UNITS ARE VISIBLE - Horse Mesa Dam, Salt River, 65 miles East of Phoenix, Phoenix, Maricopa County, AZ

369

20. CROSS SECTIONAL VIEW OF HORSE MESA, SHOWING RIGHT SPILLWAY ...  

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

20. CROSS SECTIONAL VIEW OF HORSE MESA, SHOWING RIGHT SPILLWAY SUPERSTRUCTURE AND CONCRETE PLACEMENT LINES August 2, 1927 - Horse Mesa Dam, Salt River, 65 miles East of Phoenix, Phoenix, Maricopa County, AZ

370

ConcepTest: Cross-Section of Plate Boundaries  

NSDL National Science Digital Library

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

371

ConcepTest: Cross-Sections of Plate Boundaries  

NSDL National Science Digital Library

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

372

Calculation of NP Gamma Cross Sections and Asymmetries.  

National Technical Information Service (NTIS)

Neutron-proton bremsstrahlung cross sections and asymmetries are calculated in both the Gottschalk and Thorndike geometries. The influence of off-shell terms is determined by comparing off-shell calculations to calculations using only elastic scattering p...

J. H. McGuire W. A. Pearce

1970-01-01

373

A new technique for dosimetry reaction cross-section evaluation  

SciTech Connect

Document available in abstract form only, full text of document follows: An objective of this paper is a unification of the procedure for dosimetry reaction cross-section evaluation. A set of requirements for the unified evaluation procedure is presented. A new code (ORTHO) was developed in order to meet these requirements. A statistical model, an algorithm, and the basic formulae employed in the code are described. The code was used for Ti48(n,p) reaction cross-section evaluation. The results of the evaluation are compared to International Reactor Dosimetry File (IRDF)-2002 data. The evaluated cross-sections and their correlations from this work are in good agreement with the IRDF-2002 evaluated data, whereas the uncertainties of the evaluated cross-sections are inconsistent. (authors)

Badikov, S.A. [JSC Energy and Industry Analytica, 127287, Moscow (Russian Federation)

2011-07-01

374

Cross Sections: Frame 140 Looking Aft, Frame 117 Looking Aft, ...  

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

Cross Sections: Frame 140 Looking Aft, Frame 117 Looking Aft, Frame 96 Looking Aft, Frame 78 Looking Aft, Frame 62 Looking Aft, Frame 58 Looking Aft - Wichita, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

375

Measurement of Heavy Quark cross-sections at CDF  

SciTech Connect

Abstract: The measurement of heavy quark cross-sections provides important tests of the QCD theory. This paper reviews recent measurements of single b-quark and correlated b-quark cross-sections at CDF. Two new measurements of the single b-quark production at CDF agree with the first result from CDF Run II. This clarifies the experimental situation and confirms the recent agreement of theoretical prediction with data. A new measurement of the correlated b{bar b} cross-section with dimuon events at CDF is presented. It agrees with theory and it does not confirm the anomalously large b{bar b} cross-section seen in Run I by CDF and D0 in dimuon events.

Annovi, Alberto; /Frascati

2007-09-01

376

Compound-nuclear reaction cross sections from surrogate measurements  

NASA Astrophysics Data System (ADS)

Nuclear reaction cross sections are important for a variety of applications in the areas of astrophysics, nuclear energy, and national security. When these cross sections cannot be measured directly or predicted reliably, it becomes necessary to develop indirect methods for determining the relevant reaction rates. The surrogate nuclear reactions approach is such an indirect method. First used in the 1970s for estimating (n,f) cross sections, the method has recently been recognized as a potentially powerful tool for a wide range of applications that involve compound-nuclear reactions. The method is expected to become an important focus of inverse-kinematics experiments at rare-isotope facilities. The present paper reviews the current status of the surrogate approach. Experimental techniques employed and theoretical descriptions of the reaction mechanisms involved are presented and representative cross section measurements are discussed.

Escher, Jutta E.; Burke, Jason T.; Dietrich, Frank S.; Scielzo, Nicholas D.; Thompson, Ian J.; Younes, Walid

2012-01-01

377

Factorization of the Drell-Yan cross section  

SciTech Connect

We state the weak and strong factorization theorems for the Drell-Yan cross section and outline the ingredients involved in their proof. We also discuss the physical picture implied by the factorization results and its phenomenological consequences.

Bodwin, G.T.; Brodsky, S.J.; Lepage, G.P.

1985-04-01

378

Cross section for the subthreshold fission of {sup 236}U  

SciTech Connect

The cross section for {sup 236}U fission in the neutron-energy range E{sub n} = 0.001-20 keV was measured by using the INR RAS (Institute of Nuclear Research, Russian Academy of Sciences, Moscow) LSDS-100 neutron spectrometer of the lead slowing-down spectrometer type. The resonance fission areas of the resonances at 5.45 eV and 1.28 keV were found, and the fission widths of these resonances were evaluated. The cross section for the {sup 238}U(n, f) fission process was measured, and the threshold sensitivity of the LSDS-100 to small values of fission cross sections was estimated. The well-known intermediate structure in the cross section for the neutron-induced subbarrier fission of {sup 236}U was confirmed.

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 of Physics and Power Engineering (Russian Federation)

2008-08-15

379

Experimental Determination of Collision Cross Sections for Momentum Transfer.  

National Technical Information Service (NTIS)

Effective collision cross sections for momentum transfer between electrons and neutral particles in argon, nitrogen, oxygen, helium, carbon monoxide and dioxide, nitrogen dioxide, water vapor, and mercury plasmas were measured directly by two independent ...

S. T. Demetriades G. Fonda-Bonardi G. S. Argyropoulos

1969-01-01

380

Precision measurement of the 238Pu(n,?) cross section  

NASA Astrophysics Data System (ADS)

The neutron-capture cross section for 238Pu was measured by using the detector for advanced neutron-capture experiments (DANCE) array, which is a highly segmented and highly efficient 4? ?-ray calorimeter. The neutron-capture events were recognized by the total ?-ray energy deposited in DANCE, which is equal to the reaction Q value plus the incident neutron energy. The absolute neutron-capture cross section was derived as a function of incident neutron energy from thermal to about 30 keV. The measured cross section for incident neutron energy below 18 eV was performed for the first time by using the direct method and does not support the most recently adopted changes in endf/b-vii.1 where the neutron-capture cross section was lowered by as much as a factor of ˜3 in the neighborhood of 0.3 eV from those evaluated in endf/b-vii.0.

Chyzh, A.; Wu, C. Y.; Kwan, E.; Henderson, R. A.; Gostic, J. M.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Lee, H. Y.; O'Donnell, J. M.; Ullmann, J. L.

2013-10-01

381

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

382

Some activation measurements and a comparison with theoretical (n, 2n) cross sections and isomeric cross section ratioss  

Microsoft Academic Search

Cross sections are measured for the reactions Co⁵⁹(n,2n), Zn\\/sup ; 64\\/(n,2n), and Zn⁶⁴(n,p) at 13.5 to 14.8 Mev. At 14.7 plus or minus 0.3 ; Mev, 20 plus or minus 5 mu b is obtained for the S³² (n,t) cross section ; and an upper limit of 0.1 mb for Ca⁴°(a,t). The Co⁵⁸ isomeric cross ; section ratio for the

E. Weigold; R. N. Glover

1962-01-01

383

Theoretical photodetachment cross section for He(4Po)  

Microsoft Academic Search

We report the first calculation of the photodetachment cross section for the metastable, 1s 2s 2p 4Po state of He-. Extensive configuration-interaction wave functions and the Stieltjes-moment-theory technique were used to determine the total cross section from threshold to 3.0 eV. The 1s 2p24Pe state of He- gives rise to a very large (~ 24 × 10-16 cm2) and narrow

A. U. Hazi; K. Reed

1981-01-01

384

Total cross sections for positron and electron scattering from pyrimidine  

Microsoft Academic Search

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

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

2010-01-01

385

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

386

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

387

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

388

Intermediate structure studies of 234U cross sections  

Microsoft Academic Search

Neutron induced fission and total cross sections of 234U have been measured over the neutron energy range from a few eV to 8.9 MeV. Neutron and fission widths for 118 cross section resonances below 1500 eV have been determined and give a class I level spacing of 10.6 +\\/- 0.5 eV and an s-wave strength function of (0.86 +\\/- 0.11)

G. D. James; J. W. T. Dabbs; J. A. Harvey; N. W. Hill; R. H. Schindler

1977-01-01

389

International evaluation cooperation Subgroup 7: Multigroup cross section processing  

Microsoft Academic Search

The chairmen of the ENDF\\/B, JEF, EFF, and JENDL evaluated data files adopted a proposal to develop a fine-group processed cross section library based on the VITAMIN'' concept. The authors listed above, with support from others, are participating in this project. The end result will be a pseudo-problem-independent fine-group cross section library generated from the latest evaluated data in ENDF\\/B-VI,

R. W. Roussin; J. E. White; E. Sartori; G. Panini; R. MacFarlane; D. Muir; M. Mattes; I Hasegawa

1991-01-01

390

Neutron Cross Section Evaluations for Actinides at Intermediate Energies  

Microsoft Academic Search

Investigations aimed at the development of neutron cross-section evaluations and creation of the complete nuclear data files for actinides in the range up to 150 MeV are discussed. The coupled-channel optical model has been used to calculate the neutron total, elastic, and reaction cross sections and the elastic scattering angular distributions. The parameters of the optical model have been determined

A. V. IGNATYUK; E. V. GAI; V. P. LUNEV; N. N. TITARENKO; N. SHUBIN; W. Gudowski

391

ELASTIC AND NONELASTIC NEUTRON CROSS SECTIONS FOR BERYLLIUM  

Microsoft Academic Search

A time-of-flight technique was used to measure angunlar distributions ; for the elastic scattering of neutrons from beryllium in the energy range from ; 2.6 to 6.0 Mev. Total neutron cross sections were also measured and the ; following nonelastic (total minus elastic) cross sections obtained: 2.60 Mev ; (0.27 plus or minus 0.13 barn). 3.50 (0.43 plus or minus

J. B. Marion; J. S. Levin; L. Cranberg

1959-01-01

392

Importance of Neutron Cross-Sections for Transmutation  

Microsoft Academic Search

Accurate neutron cross-section data is fundamental to the reliable design of any transmutation device, and, in particular, of an Accelerator-Driven System (ADS). Calculations of the behaviour of the core depend strongly on the cross-section data: parameters such as the multiplication coefficient, power densities or reactivity may vary significantly depending on the nuclear-data (ND) library used. These potential discrepancies justify the

A. HERRERA-MARTÍNEZ; M. DAHLFORS; Y. KADI; G. T. PARKS

393

Calculation of Neutron Cross Sections on Nb for JENDL-4  

Microsoft Academic Search

Nuclear data of Nb in the Japanese Evaluated Nuclear Data Library JENDL-3.3 were reexamined in the incident neutron energy range from 10keV to 20MeV toward JENDL-4. Cross sections, differential and double-differential cross sections were calculated on the basis of nuclear reaction models such as the spherical optical model, the distorted wave Born approximation, the Kalbach preequilibrium model, and the Hauser-Feshbach

Akira ICHIHARA; Satoshi KUNIEDA; Keiichi SHIBATA

2008-01-01

394

Measurement of the cross section for gammagamma-->pp¯  

Microsoft Academic Search

A measurement of the cross section for gammagamma-->pp¯ is performed at two-photon center-of-mass energies between 2.00 and 3.25 GeV. These results are obtained using e+e--->e+e-pp¯ events selected from 1.31 fb-1 of data taken with the CLEO II detector. The measured cross section is in reasonable agreement with previous measurements and is in excellent agreement with recent calculations based on a

M. Artuso; D. He; M. Goldberg; N. Horwitz; R. Kennett; G. C. Moneti; F. Muheim; Y. Mukhin; S. Playfer; Y. Rozen; S. Stone; M. Thulasidas; G. Vasseur; G. Zhu; J. Bartelt; S. E. Csorna; Z. Egyed; V. Jain; P. Sheldon; D. S. Akerib; B. Barish; M. Chadha; S. Chan; D. F. Cowen; G. Eigen; J. S. Miller; C. O'grady; J. Urheim; A. J. Weinstein; D. Acosta; M. Athanas; G. Masek; H. Paar; M. Sivertz; A. Bean; J. Gronberg; R. Kutschke; S. Menary; R. J. Morrison; S. Nakanishi; H. N. Nelson; T. K. Nelson; J. D. Richman; A. Ryd; H. Tajima; D. Schmidt; D. Sperka; M. S. Witherell; M. Procario; S. Yang; R. Balest; K. Cho; M. Daoudi; W. T. Ford; D. R. Johnson; K. Lingel; M. Lohner; P. Rankin; J. G. Smith; J. P. Alexander; C. Bebek; K. Berkelman; D. Besson; T. E. Browder; D. G. Cassel; H. A. Cho; D. M. Coffman; P. S. Drell; R. Ehrlich; R. S. Galik; M. Garcia-Sciveres; B. Geiser; B. Gittelman; S. W. Gray; D. L. Hartill; B. K. Heltsley; C. D. Jones; S. L. Jones; J. Kandaswamy; N. Katayama; P. C. Kim; D. L. Kreinick; G. S. Ludwig; J. Masui; J. Mevissen; N. B. Mistry; C. R. Ng; E. Nordberg; M. Ogg; J. R. Patterson; D. Peterson; D. Riley; S. Salman; M. Sapper; H. Worden; F. Würthwein; P. Avery; A. Freyberger; J. Rodriguez; R. Stephens; J. Yelton; D. Cinabro; S. Henderson; K. Kinoshita; T. Liu; M. Saulnier; F. Shen; R. Wilson; H. Yamamoto; B. Ong; M. Selen; A. J. Sadoff; R. Ammar; S. Ball; P. Baringer; D. Coppage; N. Copty; R. Davis; N. Hancock; M. Kelly; N. Kwak; H. Lam; Y. Kubota; M. Lattery; J. K. Nelson; S. Patton; D. Perticone; R. Poling; V. Savinov; S. Schrenk; R. Wang; M. S. Alam; I. J. Kim; B. Nemati; J. J. O'neill; H. Severini; C. R. Sun; M. M. Zoeller; G. Crawford; C. M. Daubenmier; R. Fulton; D. Fujino; K. K. Gan; K. Honscheid; H. Kagan; R. Kass; J. Lee; R. Malchow; F. Morrow; Y. Skovpen; M. Sung; C. White; J. Whitmore; P. Wilson; F. Butler; X. Fu; G. Kalbfleisch; M. Lambrecht; W. R. Ross; P. Skubic; J. Snow; P. L. Wang; M. Wood; D. Bortoletto; D. N. Brown; J. Fast; R. L. McIlwain; T. Miao; D. H. Miller; M. Modesitt; S. F. Schaffner; E. I. Shibata; I. P. Shipsey; P. N. Wang; M. Battle; J. Ernst; H. Kroha; S. Roberts; K. Sparks; E. H. Thorndike; C. H. Wang; J. Dominick; S. Sanghera; V. Shelkov; T. Skwarnicki; R. Stroynowski; I. Volobouev; P. Zadorozhny

1994-01-01

395

Review of multigroup nuclear cross-section processing  

Microsoft Academic Search

These proceedings consist of 18 papers given at a seminar--workshop on ''Multigroup Nuclear Cross-Section Processing'' held at Oak Ridge, Tennessee, March 14--16, 1978. The papers describe various computer code systems and computing algorithms for producing multigroup neutron and gamma-ray cross sections from evaluated data, and experience with several reference data libraries. Separate abstracts were prepared for 13 of the papers.

D. K. Trubey; H. R. Hendrickson

1978-01-01

396

Total neutron cross sections of molybdenum, cadmium and bismuth  

Microsoft Academic Search

Total cross sections of Mo and Cd were measured by the time-of-flight method in the energy interval from 20 to 1100 keV on the neutron beam from the IBR-30 reactor transmitted through either iron or aluminium filter. The [sgrave]t values were compared with the scattering cross section data. The transmission measurements on bismuth were also made in the interval from

A. B. Popov; G. S. Samosvat

1986-01-01

397

Nucleon-nucleon cross sections in nuclear matter  

SciTech Connect

We provide a microscopic calculation of neutron-proton and neutron-neutron cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Paris potential. We investigate separately the medium effects on the effective mass and on the scattering amplitude. We determine average cross sections suitable for application in the dynamical simulation of heavy ion collisions, including a parametrization of their energy and density dependence. {copyright} {ital 1997} {ital The American Physical Society}

Schulze, H.; Schnell, A.; Roepke, G. [MPG-AG Theoretische Vielteilchenphysik, Universitaet Rostock, D-18051 Rostock (Germany); Lombardo, U. [Dipartimento di Fisica, Universita di Catania, Corso Italia 57, I-95129 Catania (Italy)

1997-06-01

398

Theoretical calculation of dielectronic recombination cross sections for hydrogenlike helium  

SciTech Connect

We have developed a simplified relativistic configuration-interaction method to calculate the dielectronic recombination cross sections and rates. In this method, the infinite resonant doubly excited states can be treated conveniently in the frame of quantum defect theory. As a stringent test, we calculated the dielectronic recombination cross sections for hydrogenlike helium. The results for the {ital KLL} and {ital KLM} resonances are in good agreement with the experimental measurement.

Wang, J.; Qu, Y.; Li, J. [Institute of Physics, P.O. Box 603, Chinese Academy of Sciences, Beijing 100080 (China)

1995-11-01

399

Dielectronic-recombination cross sections of hydrogenlike argon  

SciTech Connect

Relative dielectronic-recombination cross sections for hydrogenlike argon are presented. The contributions of the {ital KLL}, {ital KLM}, {ital KLN}, {ital KLO}, and {ital KLP} groups of resonances are compared to theoretical calculations. The experimental method consists of the formation and interaction of ions with electrons in an ion trap followed by an analysis of the extracted ions to determine relative yields. Comparison with theory shows that the total cross sections agree within {plus minus}6%.

DeWitt, D.R.; Schneider, D.; Clark, M.W.; Chen, M.H. (Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)); Church, D. (Texas A M University, College Station, Texas 77843 (United States))

1991-12-01

400

K-shell photoionization cross section of Carbon IV  

Microsoft Academic Search

An 11-state R-matrix calculation is performed to obtain cross sections for the photoionization of the 0953-4075\\/30\\/1\\/008\\/img6 ground-state of C IV. For low photon energies, corresponding solely to the 2s photoionization cross section, good agreement is found with previous calculations. For higher photon energies, permitting inner-shell photoionization of the 1s electron, much more resonance structure is found than in previous studies,

C. McGuinness; K. L. Bell; A. Hibbert

1997-01-01

401

Photoionization Cross Section and Resonance Structure of Mn+  

Microsoft Academic Search

A photoionization cross section calculation of Mn+ is performed in the formalism of many-body perturbation theory for photon energies ranging from 48 eV to 56 eV. We consider excitations from the 3p, 3d, and 4s subshells. The effects of the strong 3p?3d and 3p?4s transitions are included as resonant contributions to the total cross sections. Good agreement with experiment is

Lu Peng-Fei; Liu Jin-Chao; Yang Xiang-Dong

2006-01-01

402

Neutron Nonelastic Cross-Section Measurements on Carbon  

Microsoft Academic Search

Neutron nonelastic cross sections for carbon have been measured over the energy range from 5.8 to 12.9 Mev. The main features of the carbon nonelastic cross section as a function of neutron energy are a gradual rise from threshold (4.8 Mev) up to 7 Mev, a steep rise from 7 to 8 Mev, and an approximately constant value from 8

M. H. MacGregor; Rex Booth

1958-01-01

403

Proton-nucleus inelastic cross section at ultra high energy  

NASA Astrophysics Data System (ADS)

Energy dependence of proton-nucleus reaction cross section at very high energy is discussed. It is stressed that depending on the gluon distribution near the nuclear surface, proton-nucleous total cross section increases much more rapidly compared to the usual Glauber independent nucleon estimate. The recent observation of smaller X max than the expected value at UHECR domain can be an indication for such a mechanism.

Kodama, Takeshi; Portugal, Licínio

2011-12-01

404

CROSS SECTION EVALUATIONS FOR ENDF\\/B-VII  

Microsoft Academic Search

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

M. HERMAN; D. ROCHMAN; P. OBLOZINSKY

2006-01-01

405

The evaluation and application of redundant-cross-section covariances  

SciTech Connect

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

Muir, D.W.

1986-01-01

406

Dark adapted thresholds in young RCS rats.  

PubMed

The dark adapted thresholds of black-eyed RCS rats and cogenic controls were measured using a new psychophysical procedure that permits determination of thresholds at earlier ages than previously possible. Rats were tested longitudinally between about ages 1 and 3 months. At all ages, thresholds of RCS rats were higher than those of controls. Thresholds did not change systematically with age for either RCS rats or controls. At age 3 months, when the RCS rats' b-wave is no longer recordable, RCS thresholds are about 2.2 log units higher than those of controls. PMID:1843765

Kurylo, D D; Hansen, R M; Fulton, A B

1991-01-01

407

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.

2010-05-01

408

Electron-Impact Excitation Cross Sections for Metal Vapors  

NASA Astrophysics Data System (ADS)

Two simple scaling methods to generate integrated cross sections from plane-wave Born cross sections for dipole-allowed excitations of metal vapors by electron impact(Y.-K. Kim, Phys. Rev. A, 64), in print. are shown to produce cross sections comparable in accuracy to those obtained by more sophisticated collision theories, such as the convergent close-coupling method. The scaled cross sections ?_BE and ?f are: ?_BE=?_PW×[T/(T+B+E)], ?_f=?_PWsc×(f_mc/f_sc), where ?_PW=unscaled plane-wave Born cross section, T=incident electron energy, B=binding energy of the target electron, E=excitation energy, f_mc and f_sc are the dipole f-values calculated from multiconfiguration wave functions and single-configuration wave functions, respectively. The two scalings can be used consecutively. The scaled cross section for the 4s-4p excitation of Cu is in excellent agreement with the experiment by Ismail and Teubner.(M. Ismail and P. J. O. Teubner, J. Phys. B 28) 4149 (1995) Many examples of resonance transitions of atoms, including Ag, Au, and Hg, will be presented.

Kim, Yong-Ki

2001-10-01

409

Mental visualization of objects from cross-sectional images.  

PubMed

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

2012-01-02

410

Krypton charge exchange cross sections for Hall effect thruster models  

NASA Astrophysics Data System (ADS)

Following discharge from a Hall effect thruster, charge exchange occurs between ions and un-ionized propellant atoms. The low-energy cations produced can disturb operation of onboard instrumentation or the thruster itself. Charge-exchange cross sections for both singly and doubly charged propellant atoms are required to model these interactions. While xenon is the most common propellant currently used in Hall effect thrusters, other propellants are being considered, in particular, krypton. We present here guided-ion beam measurements and comparisons to semiclassical calculations for Kr+ + Kr and Kr2+ + Kr cross sections. The measurements of symmetric Kr+ + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr2+ + Kr reaction, we present cross section measurements for center-of-mass energies between 1 eV and 300 eV, which spans energies not previously examined experimentally. These cross section measurements compare well with a simple one-electron transfer model. Finally, cross sections for the asymmetric Kr2+ + Kr --> Kr+ + Kr+ reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 A?2 with an exception near 70-80 eV.

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

2013-04-01

411

Cross-sectional area and intensity variations of sausage modes  

NASA Astrophysics Data System (ADS)

Context. The observations obtained using the Rapid Oscillations in the Solar Atmosphere instrument (ROSA) show variations in both cross-sectional area and intensity for magnetic pores in the photosphere. Aims: We study the phase behaviour between cross-sectional area and intensity variations for sausage modes in a photospheric context. We aim to determine the wave mode by looking at the phase difference between the cross-sectional area and intensity variations. Methods: We used a straight cylinder as a model for the flux tube. The plasma is uniform both inside and outside the flux tube with a possible jump in the equilibrium values at the boundary, the magnetic field is directed along the flux tube. We derived analytic expressions for the cross-sectional area variation and the total intensity variation. Using these analytic expressions, we calculated the phase differences between the cross-sectional area and the intensity variations. These phase differences were then used to identify the wave mode. Results: We found that for slow sausage modes the cross-sectional area and intensity variations are always in phase, while for fast sausage modes the variations are in antiphase. Appendix A is available in electronic form at http://www.aanda.org

Moreels, M. G.; Goossens, M.; Van Doorsselaere, T.

2013-07-01

412

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

Microsoft Academic Search

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

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

1958-01-01

413

b Quark production cross sections and the b {minus} {bar b} correlated production cross section at CDF  

SciTech Connect

Recent results on b quark and B meson production cross sections have been obtained at {radical}s = 1.8 TeV proton-antiproton collisions using the Collider Detector Facility (CDF) at Fermilab, using the exclusive decay modes B{sup {+-}} {yields}J/{Psi} K{sup {+-}} and B{sup 0} {yields} J/{Psi} K*. Another measurement made using data from the 1988--89 run on the correlated b + {bar b} cross section is also presented.

Huffman, B.T. [Pittsburgh Univ., PA (United States); CDF Collaboration

1993-09-01

414

Effect of finite range of the NN force and NN cross section on reaction cross section for neutron rich nuclei  

Microsoft Academic Search

The reaction cross section (sigmaR) is calculated using the optical limit of the Glauber theory. A density-dependent effective nucleon-nucleon (NN) cross section sigmaNN is considered. Finite and zero range NN interactions are studied. The effect of finite range and an appropriate local density can increase sigmaR up to 20% compared to the zero range at constant density (0.16fm-3), while a

M. Ismail; A. Y. Ellithi; H. Abou-Shady

2005-01-01

415

Study on in-medium nucleon–nucleon cross sections with proton-induced reaction cross sections data  

Microsoft Academic Search

Five sets of isospin-dependent in-medium nucleon–nucleon cross sections obtained by means of many-body theories with different approaches or calculation details are tested by comparing the calculated reaction cross sections of proton-induced reactions on various targets with the experimental data. The calculations are performed by using the improved quantum molecular dynamics model. The comparison indicates that these theoretically predicted isospin-dependent in-medium

Li Ou; Zhuxia Li; Xizhen Wu

2008-01-01

416

Microwave radar detection of gas pipeline leaks  

Microsoft Academic Search

We are developing a microwave radar sensing and imaging system to detect and locate gas leaks in natural gas pipelines. The underlying detection principle is radar backscattering from the index-of-refraction inhomogeneities introduced by the dispersion of methane in air. An essential first step in the development effort is modeling to estimate the radar cross section. This paper describes the modeling

N. Gopalsami; D. B. Kanareykin; V. D Asanov; S. Bakhtiari; A. C. Raptis

2002-01-01

417

Microwave Radar Detection of Gas Pipeline Leaks  

Microsoft Academic Search

We are developing a microwave radar sensing and imaging system to detect and locate gas leaks in natural gas pipelines. The underlying detection principle is radar backscattering from the index-of-refraction inhomogeneities introduced by the dispersion of methane in air. An essential first step in the development effort is modeling to estimate the radar cross section. This paper describes the modeling

N. Gopalsami; D. B. Kanareykin; V. Asanov; S. Bakhtiari; A. C. Raptis

2003-01-01

418

Determining the partial photoionization cross-sections of ethyl radicals.  

PubMed

Using a crossed laser-molecular beam scattering apparatus, these experiments photodissociate ethyl chloride at 193 nm and detect the Cl and ethyl products, resolved by their center-of-mass recoil velocities, with vacuum ultraviolet photoionization. The data determine the relative partial cross-sections for the photoionization of ethyl radicals to form C2H5+, C2H4+, and C2H3+ at 12.1 and 13.8 eV. The data also determine the internal energy distribution of the ethyl radical prior to photoionization, so we can assess the internal energy dependence of the photoionization cross-sections. The results show that the C2H4++H and C2H3++H2 dissociative photoionization cross-sections strongly depend on the photoionization energy. Calibrating the ethyl radical partial photoionization cross-sections relative to the bandwidth-averaged photoionization cross-section of Cl atoms near 13.8 eV allows us to use these data in conjunction with literature estimates of the Cl atom photoionization cross-sections to put the present bandwidth-averaged cross-sections on an absolute scale. The resulting bandwidth-averaged cross-section for the photoionization of ethyl radicals to C2H5+ near 13.8 eV is 8+/-2 Mb. Comparison of our 12.1 eV data with high-resolution ethyl radical photoionization spectra allows us to roughly put the high-resolution spectrum on the same absolute scale. Thus, one obtains the photoionization cross-section of ethyl radicals to C2H5+ from threshold to 12.1 eV. The data show that the onset of the C2H4++H dissociative photoionization channel is above 12.1 eV; this result offers a simple way to determine whether the signal observed in photoionization experiments on complex mixtures is due to ethyl radicals. We discuss an application of the results for resolving the product branching in the O+allyl bimolecular reaction. PMID:17760439

FitzPatrick, B L; Maienschein-Cline, M; Butler, L J; Lee, S-H; Lin, J J

2007-08-31

419

Photoelectric absorption cross-sections (Balucinska-Church+, 1992)  

NASA Astrophysics Data System (ADS)

Polynomial fit coefficients have been obtained for the energy dependence of the photoelectric absorption cross sections of 17 astrophysically important elements. The aim of this work is to provide convenient fits to the photoelectric absorption cross sections for each of 17 elements separately, so that spectral modelling can be performed with an absorption term containing the abundances of some or all of the elements as adjustable parameters. The fits to the individual elements can also be used independently for calculating window transmissions, gas stopping efficiency, etc. The atomic absorption cross sections were taken from Henke et al. (1982). Polynomial fits have been made to the atomic absorption cross sections in the energy range of 0.03 -- 10 keV for seventeen elements: hydrogen, helium, carbon, nitrogen, oxygen, neon, sodium, magnesium, aluminium, silicon, sulphur, chlorine, argon, calcium, chromium, iron and nickel. In the case of elements with only the K-edge in this energy range, polynomial fits were made each side of the edge; with the L-edge also present three fits were made. Polynomials of up to degree 8 were required. The functions fit Henke's data points with a typical error of 2% and a maximum error of 7%, except for points below 40~eV for argon, calcium and sodium, where the errors are larger. The effective cross section per hydrogen atom for a particular set of elemental abundances may be simply calculated from the individual cross sections. A set of routines has been written in generic FORTRAN-77 to implement these polynomial fits. The file XSCTNS.FOR contains seventeen REAL functions that will return the photoelectric cross sections for H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Cl, A, Ca, Cr, Fe, and Ni in cm**2/g, given the photon energy in eV. The file TOTLXS.FOR contains a single function that returns the effective cross section in cm**2/H atom, given the photon energy in eV and a set of seventeen relative abundances in log10. If standard abundances (as assumed by Morrison and McCammon) are to be used, the file SIGISM.FOR contains a function implementing the MM polynomials that also returns the effective photoelectric cross section in cm**2/H atom, given the photon energy in eV. It executes much faster than TOTLXS, but gives the same results as TOTLXS called with MM relative abundances. All of these routines are valid only over the photon energy range 30 - 10,000 eV. (1 data file).

Balucinska-Church, M.; McCammon, D.

1994-03-01

420

Accuracy of respiratory inductive plethysmographic cross-sectional areas.  

PubMed

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

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

1988-07-01

421

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

422

Measurements of pion single charge exchange cross sections in deuterium  

SciTech Connect

Cross sections for the d({pi}{sup {minus}},{pi}{sup 0})nn reaction at incident pion energies of 164, 263, and 371 MeV have been measured. One crate of the LAMPF Neutral Meson Spectrometer, composed of 60 CsI crystals, was used to detect both photons from the {pi}{sup 0} decay. The acceptance of the detector was obtained by comparing measured p({pi}{sup {minus}}, {pi}{sup 0})n yields to the known cross sections. No previous measurement of single charge exchange cross sections for deuterim exists between 164 MeV and 500 MeV. An impulse approximation calcuation including a realistic nucleon momentum distribution describes the energy spectra in the doubly differential cross section well. The low energy tail deviating from the calculation can be attributed to multiple-scattering effects. A Faddeev calculation at 164 MeV incorporating Pauli-blocking and multiple-scattering agrees well with the measured angular distribution. At the two higher energies the d({pi}{sup {minus}},{pi}{sup 0})nn differential cross section is essentially identical to that for p({pi}{sup {minus}},{pi}{sup 0})n, except at forward angles where the former is suppressed by the Pauli principle.

Matthews, J.L.; Park, H.T.; Pate, S.F. [and others

1995-04-01

423

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

2010-11-27

424

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 20º to 110º, 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

425

Can cross sections be accurately known for priori?  

SciTech Connect

Distinct maxima and minima in the neutron total cross section uncertainties were observed in our large scale covariance calculations using a spherical optical potential. In this contribution we investigate the physical origin of this oscillating structure. Specifically, we analyze the case of neutron reactions on {sup 56}Fe, for which total cross section uncertainties are characterized by the presence of five distinct minima at 0.1, 1.1, 5, 25, and 70 MeV. To investigate their origin, we calculated total cross sections by perturbing the real volume depth V{sub v} by its expected uncertainty {+-}{Delta}V{sub v}. Inspecting the effect of this perturbation on the partial wave cross sections we found that the first minimum (at 0.1 MeV) is exclusively due to the contribution of the s-wave. On the other hand, the same analysis at 1.1 MeV showed that the minimum is the result of the interplay between s-, p-, and d-waves; namely the change in the s-wave happens to be counterbalanced by changes in the p- and d-waves. Similar considerations can be extended for the third minimum, although it can be also explained in terms of the Ramsauer effect as well as the other ones (at 25 and 70 MeV). We discuss the potential importance of these minima for practical applications as well as the implications of this work for the uncertainties in total and absorption cross sections.

Pigni,M.T.; Dietrich, F.S.; Herman, M.; Oblozinsky, P.

2008-06-24

426

Segmental analyse and numerical verification on radar scattering characteristics of reentry capsule  

Microsoft Academic Search

During the reentering process, the RCS of the reentry capsule of Shenzhou spacecraft changed violently because of plasma sheath and wake. The change in turn affected the ground-based telemetry radar. Based on the actual measured data of C-band radar, this article analyzed the mechanism of the sudden increase and reduction of RCS of the reentry capsule and demonstrated the theory

Luo Qi; Liu Shaobin

2009-01-01

427

Accurate universal parameterization of absorption cross sections III - light systems  

NASA Astrophysics Data System (ADS)

Our prior nuclear absorption cross sections model [R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, Nucl. Instr. and Meth. B 117 (1996) 347 R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 129 (1997) 11] is extended for light systems (A<=4) where either both projectile and target are light particles or one is light particle and the other is 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. As a result the extended model can reliably be used in all studies where there is a need for absorption cross sections.

Tripathi, R. K.; Cucinotta, F. A.; Wilson, J. W.

1999-09-01

428

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

429

Measurement of the NP Elastic Cross Section by Neutron Transmission  

NASA Astrophysics Data System (ADS)

There are very few previous measurements of the cross section for neutron-proton elastic scattering at energies between 200 and 500 keV. To improve this situation, we used a pulsed proton beam from the Van de Graaff accelerator at the University of Kentucky to produce 200-800 keV neutrons via the ^7Li(p,n)^7Be reaction. We determined the total n-p elastic cross section by measuring the transmission of the neutron beam in samples of CH2 and carbon, using a BC501 liquid scintillator. The cross section obtained by taking ratios between normalized sample-in and sample-out yields is independent of both detector efficiency and dead time.

Daub, Brian; Kovash, Michael; Henzl, Vladimir; Shoniyozov, Khayrullo

2010-11-01

430

K and L shell x-ray fluorescence cross sections  

SciTech Connect

The K and L shell x-ray fluorescence (XRF) cross sections for elements with 13 {le} Z {le} 92 and 35 {le} Z {le} 92, respectively, are calculated for an incident photon energy range 1-200 keV. The XRF cross sections for K{alpha}, K{beta}, Ll, L{alpha}, L{beta}, and L{gamma} groups of x rays are tabulated. These calculations use the comprehensive sets of physical parameters currently considered most reliable, namely, theoretical partial photoionization cross sections and x-ray emission rates of Scofield, K shell fluorescence yields compiled by Hubbell, and L{sub i} subshell fluorescence yields, Coster-Kronig transition probabilities, and K to L{sub i} subshell vacancy-transfer probabilities based on the Dirac-Hartree-Slater model. 28 refs., 3 figs., 2 tabs.

Puri, S.; Chand, B.; Mehta, D. [Panjab Univ., Chandigarn (India)

1995-11-01

431

Cross sections of proton induced reactions on natSb  

NASA Astrophysics Data System (ADS)

To provide experimental activation cross sections for developing theoretical models and codes allowing calculation of probability of nuclear reactions and data for different practical applications, we perform a systematic study of light ion induced nuclear reactions on various target materials. In this work we studied the proton induced reactions on natural antimony. Excitation functions for formation of 118,119m,119g,121m,121g,123mTe, 117,118m,120m,122gSb and 117mSn were determined up to 36 MeV. The cross sections were measured with the activation method using a stacked target irradiation technique. The experimental cross section data of the investigated reactions were compared with values reported in literature and results of theoretical calculations provided by the TALYS code. From a fit to the newly measured data integral thick target yields were calculated and compared with experimental integral yield data reported in the literature.

Takács, S.; Takács, M. P.; Hermanne, A.; Tárkányi, F.; Adam Rebeles, R.

2013-02-01

432

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

433

Recent advances in modeling fission cross sections over intermediate structures  

SciTech Connect

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

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

2009-01-01

434

Application of simple ramsauer model to neutron total cross sections  

SciTech Connect

The simple nuclear Ramsauer model has been used successfully to fit neutron cross sections for three decades, but has not been widely used because the foundations of the model seem to be so unrealistic. We have shown that the Glauber calculations with the inclusion of refraction and optical model calculations essentially validate this simple model for neutron total cross sections in the neutron energy range of 5-50 MeV. This model yields a simple formula for parameterizing the energy dependence of the neutron cross section. We have applied the model to nuclei ranging from vanadium to bismuth. With the addition of a single parameter, we can improve these fits to less than 1.5%.

Bauer, R.W.; Anderson, J.D.; Grimes, S.M.; Madsen, V.A.

1997-04-29

435

Thermal neutron capture cross section of {sup 74}Ge  

SciTech Connect

The thermal neutron capture cross sections of the {sup 74}Ge(n,{gamma}){sup 75}Ge and the {sup 74}Ge(n,{gamma}){sup 75m}Ge reactions have been measured by the activation method. Cold neutrons were used to activate GeO{sub 2} targets depleted in {sup 76}Ge. From the decay spectra of {sup 75}Ge measured with high-purity germanium detectors, the cross sections relative to {sup 197}Au were derived. For the {sup 74}Ge(n,{gamma}){sup 75m}Ge reaction, a value of (130.5+-5.6) mb was found and the ground state was populated with a cross section of (497+-52) mb.

Meierhofer, G.; Grabmayr, P.; Jochum, J.; Kudejova, P.; Canella, L.; Jolie, J. [Kepler Center for Astro and Particle Physics, Universitaet Tuebingen, D-72076 Tuebingen (Germany); Forschungs-Neutronenquelle Heinz Maier-Leibnitz FRM II, Technische Universitaet Muenchen, D-85747 Garching (Germany); Institut fuer Radiochemie, Technische Universitaet Muenchen, D-85748 Garching (Germany); Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Cologne (Germany)

2010-02-15

436

Light stops emerging in WW cross section measurements?  

NASA Astrophysics Data System (ADS)

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

Rolbiecki, Krzysztof; Sakurai, Kazuki

2013-09-01

437

Bayesian Analysis of Inconsistent Measurements of Neutron Cross Sections  

SciTech Connect

The evaluation of neutron cross sections as a function of energy is fraught with inconsistent measurements. I describe a Bayesian approach to deal with the inconsistencies by probabilistically modeling the possibility of discrepant data and data sets with long-tailed likelihood functions. Systematic normalization uncertainties in each data set are included by considering the normalization to be a variable with specified uncertainty. By characterizing its uncertainty with a mixture of Cauchy and Gaussian distributions, data sets that disagree with the majority of others are given less weight in terms of normalization, but still provide useful information about the energy dependency of the cross sections. I demonstrate the approach with data sets of neutron fission cross sections for americium 243. Samples from the posterior obtained with the Markov Chain Monte Carlo technique are used to estimate the posterior mean and standard error.

Hanson, Kenneth M. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2005-11-23

438

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

439

Cross-sectional HIV incidence estimation in HIV prevention research.  

PubMed

Accurate methods for estimating HIV incidence from cross-sectional samples would have great utility in prevention research. This report describes recent improvements in cross-sectional methods that significantly improve their accuracy. These improvements are based on the use of multiple biomarkers to identify recent HIV infections. These multiassay algorithms (MAAs) use assays in a hierarchical approach for testing that minimizes the effort and cost of incidence estimation. These MAAs do not require mathematical adjustments for accurate estimation of the incidence rates in study populations in the year before sample collection. MAAs provide a practical, accurate, and cost-effective approach for cross-sectional HIV incidence estimation that can be used for HIV prevention research and global epidemic monitoring. PMID:23764641

Brookmeyer, Ron; Laeyendecker, Oliver; Donnell, Deborah; Eshleman, Susan H

2013-07-01

440

Measurement of Neutron Capture Cross Sections of Selenium Isotopes  

NASA Astrophysics Data System (ADS)

There have been numerous measurements of the neutron capture cross sections of the stable Se isotopes, most dating from at least 40 years ago. The various results for individual isotopes are often in poor agreement with one another, but as yet there has been no attempt at a systematic measurement of the capture cross sections leading to all seven radioisotopes formed from capture by natural Se, which range in halflife from 17 s to 120 d. Using cadmium-shielded and unshielded irradiations of natural Se in various irradiation sites in OSU's TRIGA reactor, we have determined the thermal cross sections and resonance integrals for captures leading to ^75,77m,79m,81g,81m,83g,83mSe.

Dearmon, Howard D.; Krane, Kenneth S.

2011-10-01

441

The critical cross-section of a vortex  

NASA Astrophysics Data System (ADS)

This paper discusses the problem of critical-flow cross-sections in vortex flows. It is shown that there are two different types of vortex flows, A-type and B-type vortices (say). An A-type vortex approaches its critical flow state as its cross-sectional area increases and departs from the critical state as the cross-sectional area is decreased. This property is associated with the particular dependence of total pressure and circulation on the stream function, and it holds for both subcritical and supercritical A-type vortices. On the other hand, both subcritical and supercritical B-type vortices approach their critical flow states as their cross-sectional areas are decreased and depart from their critical states for increasing cross-sectional area. As was shown by Benjamin, setting the first variation of the flow force with respect to the stream function equal to zero leads to Euler's equation of motion. The second variation also vanishes if the corresponding flow state is critical. In this case the sign of the third variation decides whether the flow is an A-type or a B-type vortex. Within the framework of inviscid-fluid flow theory the type of a vortex is preserved unless vortex breakdown occurs. Making use of the knowledge that vortex flows are controlled by two different types of critical-flow cross-sections a variety of vortex flow phenomena are investigated, including the two types of inlet vortices that are observed upstream of jet engines, the behavior of vortex valves, the flow characteristics of liquid-fuel atomizers and the bath tub vortex.

Keller, Jakob J.

1995-01-01

442

Microwave radar detection of gas pipeline leaks.  

SciTech Connect

We are developing a microwave radar sensing and imaging system to detect and locate gas leaks in natural gas pipelines. The underlying detection principle is radar backscattering from the index-of-refraction inhomogeneities introduced by the dispersion of methane in air. An essential first step in the development effort is modeling to estimate the radar cross section. This paper describes the modeling results and the experimental efforts underway to validate the model. For the case of leaks from small holes in a pressurized gas pipeline, we modeled the gas dynamics of the leak jet to determine the plume geometry and the variation of methane concentration in air as a function of distance from the leak source. From the static and dynamic changes in the index of refraction in the turbulent plume, the radar backscatter cross sections were calculated. The results show that the radar cross sections of the leak plumes should be detectable by special-purpose radars.

Gopalsami, N.; Kanareykin, D. B.; Asanov, V. D; Bakhtiari, S.; Raptis, A. C.

2002-10-02

443

Density distribution of 8B studied via reaction cross sections  

NASA Astrophysics Data System (ADS)

Reaction cross sections (?R) for 8B on Be, C and Al targets were measured at energies of 40A and 60A MeV. The density distribution of 8B was studied through a ?2-fitting procedure on the ?R including the high-energy data using the optical limit of Glauber theory with assumptions on the enhancement of the ?R at low energies. The result shows a long tail in the density distribution. Large one-proton removal cross sections were also observed to support the existence of a long proton tail consistent with its binding energy.

Fukuda, M.; Mihara, M.; Fukao, T.; Fukuda, S.; Ishihara, M.; Ito, S.; Kobayashi, T.; Matsuta, K.; Minamisono, T.; Momota, S.; Nakamura, T.; Nojiri, Y.; Ogawa, Y.; Ohtsubo, T.; Onishi, T.; Ozawa, A.; Suzuki, T.; Tanigaki, M.; Tanihata, I.; Yoshida, K.

1999-08-01

444

Electron-Impact Ionization Cross Sections for Molecular Ions  

Microsoft Academic Search

The binary-encounter-Bethe (BEB) model for electron-impact total ionizaton cross sections of neutral molecules(Y.-K. Kim and M. E. Rudd, Phys. Rev. A 50), 3954 (1994). has been modified for ionic targets. For a neutral molecule, the BEB cross section per molecular orbital is given by sigma_BEB=frac4pi a_0^2N(R\\/B)^2t+u+1 [ frac ln t2 (1-frac 1t^2)+1-frac 1t-frac ln t1+t ], where a_0=Bohr radius, N=electron

Y.-K. Kim; W. M. Huo; M. A. Ali

1998-01-01

445

Measurement of correlated b quark cross sections at CDF  

SciTech Connect

Using data collected during the 1992--93 collider run at Fermilab, CDF has made measurements of correlated b quark cross section where one b is detected from a muon from semileptonic decay and the second b is detected with secondary vertex techniques. We report on measurements of the cross section as a function of the momentum of the second b and as a function of the azimuthal separation of the two b quarks, for transverse momentum of the initial b quark greater than 15 GeV. Results are compared to QCD predictions.

Gerdes, D.; CDF Collaboration

1994-09-01

446

Hadronic absorption cross sections of B{sub c}  

SciTech Connect

The cross sections of B{sub c} absorption by {pi} mesons are calculated using a hadronic Lagrangian based on the SU(5) flavor symmetry. Calculated cross sections are found to be in the ranges 2-7 mb and 0.2-2 mb for the processes B{sub c}{sup +}{pi}{yields}DB and B{sub c}{sup +}{pi}{yields}D*B*, respectively, when the monopole form factor is included. These results could be useful in calculating the production rate of B{sub c} mesons in relativistic heavy ion collisions.

Lodhi, M. A. K. [Department of Physics, MS 1051, Texas Tech University, Lubbock, Texas 79409 (United States); Akram, Faisal; Irfan, Shaheen [Center for High Energy Physics, Punjab University, Lahore (Pakistan)

2011-09-15

447

Inclusive jet cross section measurement at D0  

SciTech Connect

We present a new preliminary measurement of the inclusive jet cross section in p{bar p} collisions based on a integrated luminosity of about 0.8 fb{sup -1}. The data were acquired using the D0 detector between 2002 and 2005. Jets are reconstructed using an iterative cone algorithm with radius R{sub 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.

Voutilainen, M.; /Nebraska U. /Helsinki Inst. of Phys.

2006-09-01

448

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

449

Interaction cross sections for light neutron-rich nuclei  

NASA Astrophysics Data System (ADS)

Interaction cross sections for nuclei with Z=2-12 on a 12C target are calculated in the Glauber model with matter densities obtained from Skyrme Hartree-Fock and relativistic Dirac potentials. The shell-model orbital occupations and separation energies are taken from configuration-mixing calculations and experimental spectroscopic data. Halo effects are present in the most neutron-rich C and N isotopes. The rms matter radii and interaction cross section exhibit a kink at N=14 which can be associated with a change in the mean-field potential when the 1s1/2 orbit is being filled.

Brown, B. A.; Typel, S.; Richter, W. A.

2002-01-01

450

Charge Influence on Mini Black Hole's Cross Section  

NASA Astrophysics Data System (ADS)

In this work we study the electric charge effect on the cross section production of charged mini black holes (MBH) in accelerators. We analyze the charged MBH solution using the fat brane approximation in the context of the ADD model. The maximum charge-mass ratio condition for the existence of a horizon radius is discussed. We show that the electric charge causes a decrease in this radius and, consequently, in the cross section. This reduction is negligible for protons and light-ions but can be important for heavy-ions.

Caraça, R. S.; Malheiro, M.

451

Fluctuations in photoionization cross sections of singlet planar helium  

SciTech Connect

The fluctuating part of the total photoionization cross sections up to the 20th single ionization threshold from the ground state of helium are investigated within a planar model of the atom. The calculated fluctuations reproduce existing experimental observations rather well. The fluctuations are mainly due to a dominant series of resonances which can be associated with an approximate quantum number F=N-K. As the energy approaches the double ionization threshold, the dominant role of a single series as sole contributor is apparently lost as new series start to contribute significantly to the cross sections.

Eiglsperger, Johannes; Madronero, Javier [Physik Department, Technische Universitaet Muenchen, DE-85747 Garching (Germany)

2010-09-15

452

Cross sections of deuteron induced nuclear reactions on iridium  

Microsoft Academic Search

Excitation functions of the reactions natIr(d,xn)188,189,191,193mPt and natIr(d,x)189,190g,192g,194g,194m2Ir were measured up to 40MeV using the stacked foil technique. No earlier cross sections were found in the literature. The measured experimental data were analyzed and compared to theoretical calculations based on the model code ALICE-IPPE. Use of the experimental cross sections for practical applications is also discussed.

F. Tárkányi; B. Király; F. Ditrói; S. Takács; J. Csikai; A. Hermanne; M. S. Uddin; M. Hagiwara; M. Baba; Yu. N. Shubin; S. F. Kovalev

2006-01-01

453

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 pp collisions at comparable centre-of-mass energies ?S?p ~ ?Spp ~ 200GeV, 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. Supported by the Swedish Natural Science Research Council.

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

454

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

455

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

SciTech Connect

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

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

1996-10-01

456

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

457

Measurements of (n,{gamma}) cross sections with small samples  

SciTech Connect

Neutron capture cross section data for certain isotopes of very small natural abundance are crucial for a better understanding of the s- and p-processes of nucleosynthesis. Also, recent work has shown that many previous (n,{gamma}) measurements need to be extended to lower neutron energies and that the accuracy of some previous data need to be improved. At Los Alamos we have developed a system for measuring (n,{gamma}) cross sections on samples as small as 1 mg. We give examples of measurements made with this apparatus and discuss the nuclear astrophysics motivation for these and future measurements.

Koehler, P.E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Kaeppeler, F. [KfK Karlsruhe, Institut fuer Kernphysik, D-76021 Karlsruhe (Germany)

1995-02-05

458

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

459

Solar neutrinos and low-energy nuclear cross sections  

Microsoft Academic Search

The rate of capture of solar neutrinos per 37Cl atom is found to be 0.7 × 10-35 sec-1 and 4.9 × 10-35 sec-1 for two extreme assumptions regarding the measured low-energy nuclear cross sections. The dependence of the 8B solar neutrino flux on the low-energy cross-section factor for 3He(alpha,gamma)7Be, S34 is found to be S340.7. Supported by the National Science

J. N. Bahcall; N. A. Bahcall; W. A. Fowler; G. Shaviv

1968-01-01

460

Coupling impedance of beam pipes of general cross section  

SciTech Connect

We have derived expressions for the longitudinal and transverse resistive wall coupling impedances for a beam pipe of arbitrary cross section in the ultrarelativistic limit. These expressions involve the integral of the square of the tangential magnetic fields along the wall, which can be obtained from the solution of the two-dimensional Poisson equations with a monopole and dipole singularity, respectively. Explicit results are given for beam pipes of elliptical and rectangular cross sections, including the limiting cases of a circle and a pair of parallel plates.

Gluckstern, R.L.; van Zeijts, J. (Physics Department, University of Maryland, College Park, Maryland 20742 (United States)); Zotter, B. (SL Division, CERN, Geneva 23 (Switzerland))

1993-01-01

461

Sub-barrier Fusion Cross Sections with Energy Density Formalism  

SciTech Connect

We discuss the applicability of the energy density formalism (EDF) for heavy-ion fusion reactions at sub-barrier energies. For this purpose, we calculate the fusion excitation function and the fusion barrier distribution for the reactions of 16O with 154,144Sm, 186W and 208Pb with the coupled-channels method. We also discuss the effect of saturation property on the fusion cross section for the reaction between two 64Ni nuclei, in connection to the so called steep fall-off phenomenon of fusion cross sections at deep sub-barrier energies.

Zamrun, Muhammad; Hagino, F. K.; Takigawa, N. [Department of Physics, Tohoku University, 980-8578 (Japan)

2006-08-14

462

Parameterization of ?-nucleus total reaction cross section at intermediate energies  

NASA Astrophysics Data System (ADS)

Applying a Coulomb correction factor to the Glauber model we have derived a closed expression for ?-nucleus total reaction cross section, ? R. Under the approximation of rigid projectile model, the elastic S-matrix element Sel(b) is evaluated from the phenomenological N-? amplitude and a Gaussian fit to the Helm's model form factor. Excellent agreements with the experimental data have been achieved by performing two-parameter fits to the ?-nucleus ? R data in the energy range about 75 to 193 MeV. One of the parameters was found to be energy independent while the other, as expected, shows the energy dependence similar to that of N-? total cross section.

Alvi, M. A.; Abdulmomen, M. A.

2008-12-01

463

PCS a code system for generating production cross section libraries  

SciTech Connect

This document outlines the use of the PCS Code System. It summarizes the execution process for generating FORMAT2000 production cross section files from FORMAT2000 reaction cross section files. It also describes the process of assembling the ASCII versions of the high energy production files made from ENDL and Mark Chadwick`s calculations. Descriptions of the function of each code along with its input and output and use are given. {ital This document is under construction. Please submit entries, suggestions, questions, and corrections to} {bold (ljc@llnl.gov)} 3 tabs.

Cox, L.J.

1997-04-01

464

Neutron removal cross section as a measure of neutron skin  

SciTech Connect

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

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

2010-04-15

465

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

466

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

467

QE Neutrino CC Cross Sections off 16O  

NASA Astrophysics Data System (ADS)

The charged-current quasi-elastic scattering of muon neutrino on oxygen target is computed for neutrino energy between 200 MeV and 2.5 GeV using different approximations: the Plane Wave Impulse Approximation (PWIA), the Relativistic Distorted-Wave Impulse Approximation with relativistic optical potential (RDWIA), and the Relativistic Fermi Gas Model (RFGM). The comparison with RFGM, which is widely used in data analyses of neutrino experiments, shows that the RFGM fails completely when applied to exclusive cross section data and leads to overestimated values of inclusive and total cross sections.

Butkevich, A. V.; Kulagin, S. A.

2007-12-01

468

Microscopic description of nucleon-nucleus total reaction cross sections  

SciTech Connect

Microscopic calculations of the total reaction cross sections for protons on /sup 12/C, /sup 27/Al, /sup 40/Ca, and /sup 208/Pb, and neutrons on /sup 27/Al and /sup 208/Pb have been made, which provide for the first time an excellent description of the data for projectile energies from 15 MeV through 1 GeV. The calculations are based on the experimental nucleon-nucleon total cross sections and explicitly include the effects of the real nuclear potential, the Coulomb potential, Pauli blocking, and Fermi motion.

DiGiacomo, N.J.; DeVries, R.M.; Peng, J.C.

1980-08-18

469

Ultramicrotomy of diamond films for TEM cross-section analysis.  

PubMed

Ultramicrotomy has been used to prepare TEM cross-sections of typical hard dielectric, semiconductor, and metal coatings, providing a critical capability in the study of structure-property relationships of thin films. Ultramicrotomy of thin film coatings requires meticulous attention to technique and handling. The sample to be microtomed must be very small, well bonded to the epoxy embedding medium, and precisely oriented. In this article we report the ability to microtome TEM cross-sections of diamond and cubic boron-nitride (cBN) coatings. PMID:7549004

Swab, P

1995-07-01

470

Fusion cross-sections for inertial fusion energy  

Microsoft Academic Search

The application of selective resonant tunneling model is extended from d 1 t fusion to other light nucleus fusion reactions, such as d 1 d fusion and d 1 3 He. In contrast to traditional formulas, the new formula for the cross-section needs only a few parameters to fit the experimental data in the energy range of interest. The features

XING ZHONG LI; BIN LIU; SI CHEN; QING MING WEI; HEINRICH HORA

2004-01-01

471

Thermal Neutron Capture Cross Sections of The Palladium Isotopes.  

National Technical Information Service (NTIS)

We have measured precise thermal neutron capture (gamma)-ray cross sections (sigma)(sub (gamma)) for all stable Palladium isotopes with the guided thermal neutron beam from the Budapest Reactor. The data were compared with other data from the literature a...

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

2005-01-01

472

Longitudinal Cross Section and Asymmetries for Jets in Leptoproduction.  

National Technical Information Service (NTIS)

We have calculated the longitudinal and other polarization-dependent cross sections for jet production in deep inelastic electron-proton scattering up to order alpha s of the quark-gluon coupling constant and compared them with estimates of the non-pertur...

C. Rumpf G. Kramer

1979-01-01

473

Event history analysis and the cross-section.  

PubMed

Examples are given of problems in event history analysis, where several time origins (generating calendar time, age, disease duration, time on study, etc.) are considered simultaneously. The focus is on complex sampling patterns generated around a cross-section. A basic tool is the Lexis diagram. PMID:16708345

Keiding, Niels

2006-07-30

474

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

475

18. Cross section of Mormon Flat Dam completed. Structure on ...  

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

18. Cross section of Mormon Flat Dam completed. Structure on parapet contains the operating mechanisms for the penstock gates. Power house is not yet under construction. Photographer unknown, 1926. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

476

Predictions of diffractive cross sections in proton-proton collisions  

NASA Astrophysics Data System (ADS)

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

2013-04-01

477

Scattering by a dielectric cylinder of arbitrary cross section shape  

Microsoft Academic Search

The theory and equations are developed for the scattering pattern of a dielectric cylinder of arbitrary cross section shape. The harmonic incident wave is assumed to have its electric vector parallel with the axis of the cylinder, and the field intensities are assumed to be independent of distance along the axis. Solutions are readily obtained for inhomogeneous cylinders when the

JACK H. RICHMOND

1965-01-01

478

Stellar neutron capture cross sections of the Ba isotopes.  

National Technical Information Service (NTIS)

The neutron capture cross sections of (sup 134)Ba, (sup 135)Ba, (sup 136)Ba, and (sup 137)Ba 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 (sup 7)Li(p,n)(sup 7)Be rea...

F. Voss K. Wisshak K. Guber F. Kaeppeler G. Reffo

1994-01-01

479

Cross sections for electron collisions with dimethyl ether  

NASA Astrophysics Data System (ADS)

We report a joint theoretical-experimental investigation of electron collision with dimethyl ether (DME) in the low- and intermediate-energy ranges. Experimental absolute differential, integral, and momentum-transfer cross sections for elastic e?-DME scattering are reported in the 100–1000 eV energy range. Our measurements were performed using a crossed electron-beam–molecular-beam geometry. The angular distribution of the scattered electrons was converted to absolute cross section using the relative flow technique. Theoretically, elastic differential, integral, and momentum-transfer cross sections, as well as the grand-total and total absorption cross sections for electron collision with DME are calculated in the 1–1000 eV energy range. A single-center-expansion technique combined with the Padé approximant method is used in our calculations. A comparison between the present experimental and theoretical data shows very good agreement. Moreover, comparison with theoretical and experimental data for e?-ethanol (an isomer of DME) scattering shows interesting isomeric effects.

Sugohara, R. T.; Homem, M. G. P.; Iga, I.; de Souza, G. L. C.; Machado, L. E.; Ferraz, J. R.; dos Santos, A. S.; Brescansin, L. M.; Lucchese, R. R.; Lee, M. T.

2013-08-01

480

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

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