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in creator/contributor: "Weber, F."

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Laser coupling to reduced-scale targets at NIF Early Light

Deposition of maximum laser energy into a small, high-Z enclosure in a short laser pulse creates a hot environment. Such targets were recently included in an experimental campaign using the first four of the 192 beams of the National Ignition Facility [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Technology 26, 755 (1994)], under construction at the University of California Lawrence Livermore National Laboratory. These targets demonstrate good laser coupling, reaching a radiation temp… more

Date: August 31, 2005

Creator: Hinkel, D. E.; Schneider, M. B.; Young, B. K.; Holder, J. P.; Langdon, A. B.; Baldis, H. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Impact of the nuclear equation of state on models of rotating neutron stars

The impact of the nuclear equation of state on the properties of rotating neutron stars from two different sources, stable rotation at the general relativistic Kepler period and rotation at the gravitational radiation-reaction driven instability mode, is analyzed. For this purpose models of rotating neutron stars are constructed in the framework of Einstein's theory of general relativity by applying a refined version of Hartle's perturbative stellar structure equations. The investigation is bas… more

Date: June 3, 1991

Creator: Weber, F. & Glendenning, N.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron stars, strange stars, and the nuclear equation of state

This article consists of three parts. In part one we review the present status of dense nuclear matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon population, pion condensation,.possible transition of baryon matter to quark matter). In part two we review recently performed non-rotating and rotating compact star calculations performed for these equat… more

Date: November 2, 1992

Creator: Weber, F. & Glendenning, N.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Rotating neutron stars and the equation of state of dense matter

We investigate the properties of non-rotating as well as rotating neutron stars in the framework of Einstein's theory of general relativity. The nuclear equation of state of neutron star matter (electrically charge neutral many-baryon/lepton system) is calculated for the relativistic Hartree- and Hartree-Fock approximations. The influence of two-particle correlations on the equation of state is taken into account, too. An important result is that the limiting rotational frequency of a neutron s… more

Date: May 1, 1990

Creator: Weber, F.; Glendenning, N.K. (Lawrence Berkeley Lab., CA (USA)) & Weigel, M.K. (Technische Univ. Muenchen, Garching (Germany, F.R.). Sektion Physik)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron stars, strange stars, and the nuclear equation of state

Date: November 2, 1992

Creator: Weber, F. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fast pulsars, compact stars, and the strange matter hypothesis

Part one of this paper deals with the recent finding of the possible existence of a mixed phase of baryon matter and quark matter inside neutron stars. In part two we review the theoretically determined minimum rotational periods of neutron stars, which serve to distinguish between pulsars that can be understood as rotating neutron stars and those that can not. Likely candidates for the latter are hypothetical strange stars. Their mass-radius relationship is discussed in the last part. It is po… more

Date: March 17, 1993

Creator: Weber, F. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Hadronic matter and rapidly rotating compact stars

In part one of this paper the authors review the present status of neutron star matter calculations, and introduce a representative collection of realistic nuclear equations of state which are derived for different assumptions about the physical behavior of dense matter (baryon populations, pion condensation, possible transition of baryon matter to quark matter). Part two deals with the theoretical determination of the minimum possible rotational periods of neutron stars, performed in the frame… more

Date: March 1, 1994

Creator: Weber, F.; Kettner, C. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The relativistic treatment of symmetric and asymmetric nuclear matter

In the framework of relativistic nuclear field theory the authors discuss and compare the different approaches in the treatment of nuclear-many-problem with inclusion of two-body correlations. The equations are solved self-consistently in the full Dirac space, so avoiding the ambiguities in the choice of the effective scattering amplitude. The results are compared with the standard method, where one only determines the scattering amplitude for positive energy spinors. Furthermore they tested th… more

Date: November 4, 1993

Creator: Huber, H.; Weigel, M. K. & Weber, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The First Experiments on the National Ignition Facility

A first set of laser-plasma interaction, hohlraum energetics and hydrodynamic experiments have been performed using the first 4 beams of the National Ignition Facility (NIF), in support of indirect drive Inertial Confinement Fusion (ICF) and High Energy Density Physics (HEDP). In parallel, a robust set of optical and x-ray spectrometers, interferometer, calorimeters and imagers have been activated. The experiments have been undertaken with laser powers and energies of up to 8 TW and 17 kJ in fl… more

Date: November 11, 2005

Creator: Landen, O. L.; Glenzer, S.; Froula, D.; Dewald, E.; Suter, L. J.; Schneider, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Possible new class of dense white dwarfs

If the strange quark matter hypothesis is true, then a new class of white dwarfs can exist whose nuclear material in their deep interiors can have a density as high as the neutron drip density, a few hundred times the density in maximum-mass white dwarfs and 4 {times} 10{sup 4} the density in dwarfs of typical mass, M {approximately} 0.6M{sub {circle_dot}}. Their masses fall in the approximate range 10{sup {minus}4} to 1M{sub {circle_dot}}. They are stable against acoustical modes of vibration.… more

Date: January 10, 1995

Creator: Glendenning, N.K.; Kettner, C. & Weber, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Probing High Density Plasmas With Soft X-Ray Lasers

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Date: August 1, 1997

Creator: Celliers, P.; Barbee, T. W., Jr.; Cauble, R.; Da Silva, L. B.; Decker, C. D.; Kalantar, D. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Strange stars, strange dwarfs, and planetary-like strange-matter objects

This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts--neutron stars and white dwarfs--their properties are determined by two (rather than one) parameters, the central star density and the density at the base of the nuclear crust. This leads to stellar strange-matter configurations whose properties are much more compl… more

Date: May 1, 1995

Creator: Weber, F.; Schaab, C.; Weigel, M. K. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Equation of state of neutron star matter, limiting, rotational periods of fast pulsars, and the properties of strange stars

In this paper the following items will be treated: The present status of dense nuclear matter calculations and constraints on the behavior of the associated equation of state at high densities from data on rapidly rotating pulsars. Recent finding of the likely existence of a mixed phase of baryons and quarks forming a coulomb lattice in the dense cores of neutron stars. Review of important findings of recently performed calculations of rapidly rotating compact stars. These are constructed in th… more

Date: October 25, 1993

Creator: Weber, F. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Inner-Shell Photon-Ionized X-Ray Laser at 45(Angstrom)

This report summarizes the major accomplishments of this three-year Laboratory Directed Research and Development (LDRD) Lab Wide (LW) project entitled, ''An Inner-Shell Photo-Ionized X-Ray Laser at 45 {angstrom}'', tracking code 99-LW-042. The most significant accomplishments of this project include the design of a suitable x-ray laser target, the invention of a measurement technique for the determination of rise times of x-ray pulses on the order of 50 femtoseconds, and a novel setup for gener… more

Date: February 1, 2002

Creator: Weber, F.; Celliers, P.; Moon, S.; Snavely, R. & Da Silva, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Improvements in Off-Center Focusing in an X-ray Streak Camera

Due to the planar construction of present x-ray streak tubes significant off-center defocusing is observed in both static and dynamic images taken with one-dimensional resolution slits. Based on the streak tube geometry curved photocathodes with radii of curvature ranging from 3.5 to 18 inches have been fabricated. We report initial off-center focusing performance data on the evaluation of these ''improved'' photocathodes in an X-ray streak camera and an update on the theoretical simulations to… more

Date: July 17, 2003

Creator: McDonald, J. W.; Weber, F.; Holder, J. P. & Bell, P. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser Coupling to Reduced-Scale Targets at the Early Light Program of the National Ignition Facility

A platform for analysis of material properties under extreme conditions, where a sample is bathed in radiation with a high temperature, is under development. This hot environment is produced with a laser by depositing maximum energy into a small, high-Z can. Such targets were recently included in an experimental campaign using the first four of the 192 beams of the National Ignition Facility, under construction at the University of California Lawrence Livermore National Laboratory. These target… more

Date: November 18, 2004

Creator: Hinkel, D. E.; Schneider, M. B.; Baldis, H. A.; Bower, D.; Campbell, K. M.; Celeste, J. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Properties of strange-matter stars

This paper deals with an investigation of the properties of hypothetical strange-matter stars, which are composed of u, d, s quark matter whose energy per baryon number lies below the one of {sup 56}Fe (Witten`s strange matter hypothesis). Observable quantities which allow to distinguish such objects from their ``conventional`` counterparts, neutron stars and white dwarfs, are pointed out.

Date: July 1, 1994

Creator: Weber, F.; Kettner, Ch. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Interpretation of rapidly rotating pulsars

The minimum possible rotational period of pulsars, which are interpreted as rotating neutron stars, is determined by applying a representative collection of realistic nuclear equations of state. It is found that none of the selected equations of state allows for neutron star rotation at periods below 0.8--0.9 ms. Thus, this work strongly supports the suggestion that if pulsars with shorter rotational periods were found, these are likely to be strange-quark-matter stars. The conclusion that the … more

Date: August 5, 1992

Creator: Weber, F. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Soft x-ray spectrometer operation at the National Ignition Facility

Radiation drive diagnostics during the NIF early light campaign was supported by an 18 channel soft x-ray spectrometer (Dante). In order to achieve a measurement accuracy of 2% in radiation temperature absolute calibration of the individual channels was necessary and signal distortion through long transmission lines had to be compensated for as well. For fast signals the signal attenuation due to the long (50m) cables amounted to {approx} 20% {at} 100MHz, which was corrected by a cable compensa… more

Date: April 25, 2006

Creator: Schein, J.; Dewald, E.; Campbell, K.; Turner, R.; Weber, F.; Rhodes, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurement of local gain and electron density in an yttrium x-ray laser amplifier

X-ray lasers have measured average gains significantly less than calculated and a persistently low level of spatial coherence. We have used an X-ray laser both as an injected signal to a short X-ray laser amplifier and as an interferometer beam to measure two dimensional local gain and density profiles of the X-ray laser plasma with near-1- mm resolution. The measured local gain is in agreement with atomic models, but its gain is unexpectedly spatially inhomogeneous. This inhomogeneity explains… more

Date: May 1, 1996

Creator: Cauble, R.; Da Silva, L. B.; Barbee, T., Jr.; Celliers, P.; Decker, C.; London, R. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Masks for extreme ultraviolet lithography

In extreme ultraviolet lithography (EUVL), the technology specific requirements on the mask are a direct consequence of the utilization of radiation in the spectral region between 10 and 15 nm. At these wavelengths, all condensed materials are highly absorbing and efficient radiation transport mandates the use of all-reflective optical systems. Reflectivity is achieved with resonant, wavelength-matched multilayer (ML) coatings on all of the optical surfaces - including the mask. The EUV mask ha… more

Date: September 1, 1998

Creator: Cardinale, G.; Goldsmith, J.; Kearney, P. A.; Larson, C.; Moore, C. E.; Prisbrey, S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electron Density Measurement of a Colliding Plasma Using Soft X-Ray Laser Interferometry

The understanding of the collision and subsequent interaction of counter-streaming high-density plasmas is important for the design of indirectly-driven inertial confinement fusion (ICF) hohlraums. We have employed a soft x-ray Mach-Zehnder interferometer, using a Ne- like Y x-ray laser at 155 {angstrom} as the probe source, to study interpenetration and stagnation of two colliding plasmas. We observed a peaked density profile at the symmetry axis with a wide stagnation region with width of ord… more

Date: May 1, 1996

Creator: Wan, A. S.; Back, C. A.; Barbee, T. W., Jr.; Cauble, R.; Celliers, P.; DaSilva, L. B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Stability of strange quark stars with nuclear crusts against radial oscillations

This paper investigates the stability of the complete sequence of strange-matter stars with nuclear crusts against radial pulsations (acoustical modes). It is found that a broad class of white dwarf- like strange stars is stable against such pulsations. The same holds for the much denser strange stars, which are the strange counter-parts of neutron stars. All stars possessing still higher central densities (e.g., charm stars) turn out to be unstable.

Date: December 5, 1994

Creator: Kettner, Ch.; Weigel, M. K.; Weber, F. & Glendenning, N. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization and modeling of soft x-ray lasers

This paper describes our theoretical, numerical, and experimental development of short-pulse-duration, high brightness, and enhanced coherence x-ray lasers (XRLs) as sources suitable for applications as imaging diagnostics for laser plasmas.

Date: October 1, 1995

Creator: Wan, A. S.; Cauble, R.; Celliers, P.; DaSilva, L. B.; Libby, S. B.; London, R. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department