Grazing incidence metal mirrors as the final elements in a laser driver for inertial confinement fusion (open access)

Grazing incidence metal mirrors as the final elements in a laser driver for inertial confinement fusion

Grazing incidence metal mirrors (GIMMs) have been examined to replace dielectric mirrors for the final elements in a laser beam line for an inertial confinement fusion reactor. For a laser driver with a wavelength from 250 to 500 nm in a 10-ns pulse, irradiated mirrors made of Al, Al alloys, or Mg were found to have calculated laser damage limits of 0.3--2.3 J/cm{sup 2} of beam energy and neutron lifetime fluence limits of over 5 {times} 10{sup 20} 14 MeV n/cm{sup 2} (or 2.4 full power years when used in a 1000-MW reactor) when used at grazing incidence (an angle of incidence of 85 degrees) and operated at room temperature or at 77 K. A final focusing system including mirrors made of Al alloy 7457 at room temperature or at liquid nitrogen temperatures used with a driver which delivers 5 MJ of beam energy in 32 beams would require 32 mirrors of roughly 10 m{sup 2} each. This paper briefly reviews the methods used in calculating the damage limits for GIMMs and discusses critical issues relevant to the integrity and lifetime of such mirrors in a reactor environment. 10 refs., 3 figs., 1 tab.
Date: November 19, 1990
Creator: Bieri, R. L. & Guinan, M. W.
Object Type: Article
System: The UNT Digital Library
D-Zero Central Calorimeter Technical Appendix to Cryogenic Pressure Vessels (open access)

D-Zero Central Calorimeter Technical Appendix to Cryogenic Pressure Vessels

DO (D Zero) is a large Liquid Argon (LAr) HEP Calorimeter designed to function in the laboratories P-Pbar collider at the DO section of the Tevatron accelerator. It contains 5,000 gls. of LAr in the CC cryostat, and 3,000 gls. in each of two, a north and south, EC cryostats. These low pressure vessels are filled with detector modules built of stainless steel, copper and depleted uranium. The LAr functions as the ionization medium, and the spatial and temporal of the collection of the charge of the electrons produced signals the passsage of charged particles. The collection of these charges in 4 pi is related to the energy of the particles, and their measurement is called calorimetry. The contained LAr (T=90K) is isolated from the ambient temperatures in specially designed, vacuum and superinsulated, vessels (cryostats) provided with liquid nitrogen, heat of vaporization, cooling.
Date: November 19, 1990
Creator: Mulholland, G. T. & Rucinski, R. A.
Object Type: Report
System: The UNT Digital Library
Inverse Compton conversion. Final report (open access)

Inverse Compton conversion. Final report

Inverse Compton conversion has been proposed as an alternative to the bremsstrahlung conversion process as a method of transforming the kinetic energy of an electron beam into a directed beam of photons. An electron beam with incident electron kinetic energy E{sub o} enters a volume of dimension L containing a photon gas, which is characterized by a blackbody temperature E{sub bb} and a density {rho}{sub {gamma}}. The electrons will inverse-Compton scatter with individual photons in the photon gas. In this process, energy is transferred to the photons, which are then emitted in the forward direction. The resultant photon beam could be used to deliver a radiation dose to a distant target. This report discusses the theoretical formulation of the problem, presents sample results, and describes the computer code developed to analyze this concept.
Date: November 19, 1990
Creator: Weitz, R. L.
Object Type: Report
System: The UNT Digital Library
Shape Isomers: Mean-Field Description and Beyond (open access)

Shape Isomers: Mean-Field Description and Beyond

Nuclear Hartree-Fock (HF) + BCS calculations have led to predictions of shape isomerism in isotopes of Pt, Hg and Os nuclei. These have been confirmed through the observation of superdeformed rotational bands in {sup 190,{hor ellipsis},194}Hg. Encouraged by these measurements and similar observations in {sup 194}Pb, we have extended these calculations to a wide range of contiguous nuclei. These HF results, for {sup 192,194}Pt, {sup 190,{hor ellipsis},198}Hg and {sup 194}Pb, have been employed in a Generator Coordinate Method (GCM) calculation utilizing the quadrupole deformation as the generating variable. The resulting spectra confirm the conclusions drawn from the HF results and agree with those experiments which have been performed. Adding a phenomenological assumption for the moments of inertia of our GCM states, we can construct the radiative transitions within and out of the superdeformed band. The results are in good agreement with the observed de-population of the superdeformed band built upon the shape isomer both in minimum angular momentum and in rapidity of de-population. Inferences for the existence of shape isomers will be drawn. 19 refs., 4 figs.
Date: November 19, 1990
Creator: Bonche, P.; Krieger, S. J.; Weiss, M. S. (Lawrence Livermore National Lab., CA (USA)); Dobaczewski, J. (Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej); Flocard, H. (Paris-11 Univ., 91 - Orsay (France). Div. de Physique Theorique); Heenen, P. H. (Universite Libre de Bruxelles (Belgium)) et al.
Object Type: Article
System: The UNT Digital Library