5 Matching Results

Results open in a new window/tab.

Imaging system for obtaining space- and time-resolved plasma images on TMX (open access)

Imaging system for obtaining space- and time-resolved plasma images on TMX

A Reticon 50 x 50 photodiode array camera has been placed on Livermore's Tandem Mirror Experiment to view a 56-cm diameter plasma source of visible, vacuum-ultraviolet, and x-ray photons. The compact camera views the source through a pinhole, filters, a fiber optic coupler, a microchannel plate intensifier (MCPI), and a reducer. The images are digitized (at 3.3 MHz) and stored in a large, high-speed memory that has a capacity of 45 images. A local LSI-11 microprocessor provides immediate processing and display of the data. The data are also stored on floppy disks that can be further processed on the large Livermore Computer System. The temporal resolution is limited by the fastest MCPI gate. The number of images recorded is determined by the read-out time of the Reticon camera (minimum 0.9 msec). The spatial resolution of approximately 1.4 cm is fixed by the geometry and the pinhole of 0.025 cm. Typical high-quality color representation of some plasma images are included.
Date: April 8, 1980
Creator: Koehler, H.A. & Frerking, C.E.
System: The UNT Digital Library
Study of optical model parameters for high energy neutron cross sections from 5 to 50 MeV in the mass-140 region (open access)

Study of optical model parameters for high energy neutron cross sections from 5 to 50 MeV in the mass-140 region

A study of the neutron optical potential on nuclei near mass-140 was begun to extend the energy range and improve the precision of previous neutron total cross section measurements. The extended energy range of this measurement reveals maxima and minima in the total cross section that are evidence of the nuclear Ramsauer effect. A 100-MeV linear accelerator is used to produce a continuum of neutron energies from a Ta-Be conversion target. A 250-meter flight path is used to measure neutron energies by the time-of-flight method. Transmission data for /sup 140/Ce and transmission ratios for /sup 142/Ce, /sup 141/Pr, and /sup 139/La relative to /sup 140/Ce were obtained. The /sup 140/Ce data have a precision of 1 to 3% and the ratios are obtained with a precision of about 0.3%. To analyze these total cross section data a computer code was developed to calculate the total elastic, reaction, and differential elastic scattering cross sections for a neutron interacting with a nucleus. The interaction is represented by a spherically symmetric complex potential that includes spin-orbit coupling. The parameters of this potential were adjusted to approximate the /sup 140/Ce total cross over the energy range from 2.5 to 60 MeV. The energy dependence …
Date: May 8, 1980
Creator: Phillips, T.W.; Camarda, H.S. & White, R.M.
System: The UNT Digital Library
Dependence of strength on particle size in graphite (open access)

Dependence of strength on particle size in graphite

The strength to particle size relationship for specially fabricated graphites has been demonstrated and rationalized using fracture mechanics. In the past, similar studies have yielded empirical data using only commercially available material. Thus, experimental verification of these relationships has been difficult. However, the graphites of this study were fabricated by controlling the particle size ranges for a series of isotropic graphites. All graphites that were evaluated had a constant 1.85 g/cm/sup 3/ density. Thus, particle size was the only variable. This study also considered the particle size effect on other physical properties; coefficient of thermal expansion (CTE), electrical resistivity, fracture strain, and Young's modulus.
Date: June 8, 1980
Creator: Kennedy, E. P. & Kennedy, C. R.
System: The UNT Digital Library
Parametric study of a target factory for laser fusion (open access)

Parametric study of a target factory for laser fusion

An analysis of a target factory leading to the derivation of production rate equations has provided the basis for a parametric study. Rate equations describing the production of laser fusion targets have been developed for the purpose of identifying key parameters, attractive production techniques and cost scaling relationships for a commercial target factory.
Date: October 8, 1980
Creator: Sherohman, J. W. & Meier, W. R.
System: The UNT Digital Library
Monte Carlo calculation of flux-to-dose-rate conversion factors for energies between 0. 01 and 1. 00 MeV (open access)

Monte Carlo calculation of flux-to-dose-rate conversion factors for energies between 0. 01 and 1. 00 MeV

Gamma-ray flux-to-dose-rate conversion factors for energies between 0.01 and 1.0 MeV were computed using the Monte Carlo method for a 30-cm-thick slab having the standard-man composition. Agreement between the computed factors and standard factors (ANSI/ANS-6.1.1-1977) was optimal for energies above 0.1 MeV and was at most 30% lower (at 0.02 MeV) for energies below 0.1 MeV. The computed factors were also in agreement with experimentally-obtained factors.
Date: December 8, 1980
Creator: Tapia, C.S.
System: The UNT Digital Library