[en] The Manuel Lujan, Jr., Neutron Scattering Center (MLNSC) at the Los Alamos National Laboratory is one of four operating Short-Pulse Spallation Sources worldwide. The MLNSC target system (composed of targets, moderators, and reflectors) was first installed in 1985. The target system employs a split tungsten spallation target with a void space in between (the flux-trap gap); this target system will be upgraded in 1998. The ability to efficiently split a spallation target allowed us to introduce the concept of flux-trap moderators and ultimately the notion of backscattering and upstream moderators. The upgraded MLNSC target system will employ both flux-trap and upstream/backscattering moderators to simultaneously service 16 neutron flight paths with high-intensity neutron beams for materials science research

[en] Recently, three liner stability experiments were performed at the Pegasus II pulsed power facility to determine the asymmetric variations in the material density of a cylindrical liner during an electro-magnetically driven implosion. The initial campaign consisted of three experiments, designated LS-1, LS-2, and LS-3. LS-1 and LS-2 were driven with a peak current of approximately 4.2 MA, whereas the peak current for LS-3 was approximately 6.4 MA. All three liners initially were 0.4 mm wall aluminum cylinders with a mean radius of 2.38 cm and a height of 2.0 cm. The inner surface of each liner was coated with a thin (18--23 microm) layer of gold to aid in the determination of the position of the inner surface of the liner. Radial radiography was used to characterize the z-dependent and θ-dependent instabilities that were observed as the liner contracted

[en] The Intense Neutron Source (INS) is an Inertial Electrostatic Confinement (IEC) fusion device presently under construction at Los Alamos National Laboratory. It is designed to produce 10¹¹ neutrons per second steady-state using D-T fuel. Phase 1 operation of this device will be as a standard three grid IEC ion focus device. Expected performance has been predicted by scaling from a previous IEC device. Phase 2 operation of this device will utilize a new operating scheme, the Periodically Oscillating Plasma Sphere (POPS). This scheme is related to both the Spherical Reflect Diode and the Oscillating Penning Trap. With this type of operation the authors hope to improve plasma neutron production to about 10¹³ neutrons/second

[en] Computational fluid dynamics (CFD) is being used to analyze the design of the National Spallation Neutron Source (NSNS) target. The target is subjected to the neutronic (internal) heat generation that results from the proton collisions with the mercury nuclei. The liquid mercury simultaneously serves as the neutronic target medium, transports away the heat generated within itself, and cools the metallic target structure. Recirculation and stagnation zones within the target are of particular concern because of the likelihood that they will result in local hot spots. These zones exist because the most feasible target designs include a complete U-turn flow redirection. Although the primary concern is that the target is adequately cooled, the pressure drop from inlet to outlet must also be considered because pressure drop directly affects structural loading and required pumping power. Various design options have been considered in an effort to satisfy these design criteria. Significant improvements to the design have been recommended based on the results. Detailed results are presented for the current target design including a comparison with published pressure-drop data. Comparisons are also made with forced convection heat transfer data for liquid mercury flow in circular tubes

[en] Calculated parameters of a GS-1 intense pulse neutron source on the basis of a booster-multiplier and high-current proton accelerator of the meson facility with 600 MeV proton beam energy, 10 μs pulse duration and repetition frequency of up to 100 Hz are given. The booster-multiplier represents a breedering system of plutonium dioxide irradiated with a proton beam and cooled with water. The booster core represents plutonium oxide rod fuel assembly. Time regimes of booster-multiplier are divided in two groups determined with a set of physical problems. For investigations into nuclear physics in the region of low-lying resonances, for investigations into high-excited states of condensed media (electronvolt region of neutron energies) suggested is use of microsecond pulse regimes. It is shown that production of thermal neutron fluxes having a peak density of 5x10¹⁶ neutr/(cm²xs) is possible at a mean thermal capacity of 1 MW

[en] The Curietron is a remotely controlled afterloading machine for gynaecological low dose rate intracavitary radiotherapy. The Curietron and its installation are described together with specially designed applicators intended to produce a source geometry similar to the Manchester configuration. Some of the practical problems met are discussed. The principal value of the Curietron lies in the marked reduction of radiation exposure to all staff concerned. (author)

No abstract available

[en] There are facilities for irradiation down to 4.2 K with fast neutrons at Argonne's recently constructed Intense Pulsed Neutron Source (IPNS-I). The large irradiation volume, the neutron spectrum and flux, the ability to transfer samples without warm up, and the dedication of the facilities during the irradiation make this ideally suited for radiation damage studies on components for superconducting fusion magnets. Possible experiments are discussed on cyclic irradiation and annealing of stabilizers in a high magnetic field, mechanical tests on organic insulation irradiated at 4 K, and superconductors measured in high fields after irradiation. (orig.)

[en] A ³He spectrometer has been used to measure the neutron spectra from a 5 Ci Am/Li source at three different orientation of the source; full covariance error matrices have been calculated. (orig.)

[en] A device is described for conducting neutron radiography comprising: an on/off sealed tube neutron generator using solely a deuterium target for emitting relatively low energy neutrons having an energy level of approximately 3 MeV and an unthermalized neutron yield of at least approximately 1x10¹⁰D-D n/second, a maneuverable inspection head supporting the neutron generator and having moderating fluid therein to thermalize the neutrons emitted from the neutron source, and collimator means for directing the thermalized neutrons to an imaging plane to produce a thermal neutron radiograph