Measurements of DT and DD neutron yields by neutron activation on TFTR (open access)

Measurements of DT and DD neutron yields by neutron activation on TFTR

A variety of elemental foils have been activated by neutron fluence from TFTR under conditions with the DT neutron yield per shot ranging from 10{sup 12} to over 10{sup 18}, and with the DT/(DD+DT) neutron ratio varying from 0.5% (from triton burnup) to unity. Linear response over this large dynamic range is obtained by reducing the mass of the foils and increasing the cooling time, all while accepting greatly improved counting statistics. Effects on background gamma-ray lines from foil-capsule-material contaminants. and the resulting lower limits on activation foil mass, have been determined. DT neutron yields from dosimetry standard reactions on aluminum, chromium, iron, nickel, zirconium, and indium are in agreement within the {plus_minus}9% (one-sigma,) accuracy of the measurements: also agreeing are yields from silicon foils using the ACTL library cross-section. While the ENDF/B-V library has too low a cross-section. Preliminary results from a variety of other threshold reactions are presented. Use of the {sup 115}In(n,n) {sup 115m}In reaction (0.42 times as sensitive to DT neutrons as DD neutrons) in conjunction with pure-DT reactions allows a determination of the DT/(DD+DT) ratio in trace tritium or low-power tritium beam experiments.
Date: May 5, 1994
Creator: Barnes, C. W.; Larson, A. R.; LeMunyan, G. & Loughlin, M. J.
System: The UNT Digital Library
Stability of strange quark stars with nuclear crusts against radial oscillations (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.
System: The UNT Digital Library
Laser plasma interactions in hohlraums (open access)

Laser plasma interactions in hohlraums

Lasers plasma instabilities are an important constraint in x-ray driven inertial confinement fusion. In hohlraums irradiated with 1.06 {mu}m light on the Shiva laser, plasma instabilities were extremely deleterious, driving the program to the use of shorter wavelength light. Excellent coupling has been achieved in hohlraums driven with 0.35 {mu}m light on the Nova laser. Considerable attention is being given to the scaling of this excellent coupling to the larger hohlraums for an ignition target. Various instability control mechanisms such as large plasma wave damping and laser beam incoherence are discussed, as well as scaling experiments to check the instability levels.
Date: October 5, 1994
Creator: Kruer, W.L.
System: The UNT Digital Library
Results/prospects in E777/851/865 (open access)

Results/prospects in E777/851/865

E777 has set 90% C.L. branching ratio upper limits of 2.1 x 10{sup {minus}10} for the decays K{sup +} {yields} {pi}{sup +}{mu}{sup +}e{sup {minus}} and 4.5 x 10{sup {minus}7} for K{sup +} {yields} {pi}{sup +}A{sup 0}, where A{sup 0} is any particle of mass less than 100 MeV/c{sup 2} decaying into e{sup +}e{sup {minus}} with lifetime less than 10{sup {minus}13} sec. E851 measured the BR(K{sup +} {yields} {pi}{sup +}e{sup +}e{sup {minus}}) = (2.97{sub {minus}0.22}{sup +0.19}) x 10{sup {minus}7} and BR({pi}{sup 0} {yields} e{sup +}e{sup {minus}}) = (8.0 {+-} 2.6 {+-} 0.6) x 10{sup {minus}8}. E865 is preparing to take data in 1995 which should greatly improve these results.
Date: December 5, 1994
Creator: Lazarus, D. M.
System: The UNT Digital Library
Control of chaos in a CO2 laser (open access)

Control of chaos in a CO2 laser

Article discussing research on control of chaos in a CO2 laser.
Date: September 5, 1994
Creator: Pérez, José M.; Steinshnider, J.; Stallcup, Richard E. & Aviles, A. F.
System: The UNT Digital Library
Molten salt destruction as an alternative to open burning of energetic material wastes (open access)

Molten salt destruction as an alternative to open burning of energetic material wastes

LLNL has built a small-scale (about 1 kg/hr throughput unit to test the destruction of energetic materials using the Molten Salt Destruction (MSD) process. We have modified the unit described in the earlier references to inject energetic waste material continuously into the unit. In addition to the HMX, other explosives we have destroyed include RDX, PETN, ammonium picrate, TNT, nitroguanadine, and TATB. We have also destroyed a liquid gun propellant comprising hydroxyl ammonium nitrate, triethanolammonium nitrate and water. In addition to these pure components, we have destroyed a number of commonly used formulations, such as LX-10 (HMX/Viton), LX-16 (PETN/FPC461, LX-17 (TATB/Kel F), and PBX-9404 (HMX)/CEF/Nitro cellulose). Our experiments have demonstrated that energetic materials can be safely and effectively treated by MSD.We have also investigated the issue of steam explosions in molten salt units, both experimentally and theoretically, and concluded that steam explosions can be avoided under proper design and operating conditions. We are currently building a larger unit (nominal capacity 5 kg/hr,) to investigate the relationship between residence time, temperature, feed concentration and throughputs, avoidance of back-burn, a;nd determination of the products of combustion under different operating conditions.
Date: July 5, 1994
Creator: Upadhye, R. S.; Watkins, B. E.; Pruneda, C. O. & Brummond, W. A.
System: The UNT Digital Library
Emissions from energetic material waste during the Molten Salt Destruction process (open access)

Emissions from energetic material waste during the Molten Salt Destruction process

The Molten Salt Destruction (MSD) process is an alternative to open burn/open detonation for destroying energetic materials; MSD has inherently low gaseous emissions, and the salt bath can scrub both acidic gases and particulates. It was demonstrated that high explosives and a liquid propellant can be safely and completely destroyed using MSD. Gaseous emissions of NOx and CO are very low. Nitrate builds up in the salt bath when nitrate-rich materials are destroyed, but addition fuel reduces the nitrate to NO. A program has been begun to add catalytic materials to the bed to further reduce emissions; a small molten salt bath has been constructed for chemical kinetic studies.
Date: July 5, 1994
Creator: Watkins, B. E.; Upadhye, R. S.; Pruneda, C. O. & Brummond, W. A.
System: The UNT Digital Library
Strange-matter stars (open access)

Strange-matter stars

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 complex than those of the conventional sequence. As an example, two generically different categories of stable strange dwarfs are found, which could be the observed white dwarfs. Furthermore the authors find very-low-mass strange stellar objects, with masses as small as those of Jupiter or even lighter planets. Such objects, if abundant enough, should be seen by the presently performed gravitational microlensing searches.
Date: December 5, 1994
Creator: Weber, F.; Kettner, C.; Weigel, M. K. & Glendenning, N. K.
System: The UNT Digital Library