Search

Anomalous neutron activation of the hardened Si-doped copper cathode (Cu:Si) has been established under the combined action of electrolysis and an ultraweak thermalized neutron field (UTNF) with a flux as low as Φ n =180 n/s-cm 2 . It was found that the number of neutrons captured in the sample during relatively short electrolysis runs ( t ⩽5000 s) is in a good agreement with β − -Cu nuclide count rate from the cathode. It was also established that plastic deformation of the hardened copper cathode under the combined action of electrolysis and UTNF could be explained energetically by a model assuming a selective radiationless thermalizied neutron capture beneath the surface at the high internal strain concentration sites.

The effects of a significant decrease in the sputtering rate and of the symmetrical separation of the isotope pairs 108Pd-105Pd and 110Pd-104Pd at depths up to 500 A are experimentally detected in Pd specimens saturated with deuterium during electrolysis (i.e., having a high concentration of internal stresses). These effects are shown to be qualitatively explained using the concepts of isotope separation by centrifugation and diffusion with allowance for defects and mechanical stresses that appear in the near-surface Pd layer during deuterium penetration.

The emission of neutrons observed during cavitation in dielectric deuterated liquids (C3D6O, D2O) can be semiquantitatively explained within the framework of a proposed acceleration model. This model assumes the appearance of uncompensated charge on the walls of a cavitation bubble, which leads to spark discharge when the bubble reaches a maximum radius.

Experimental and theoretical results are presented on the nuclear pumping of XeBr*. Measurements under 10B and 3He pumping showed fluorescence efficiencies of 1%±0.5% for the B‐X emission. Detailed time‐dependent kinetic modeling was not in agreement, with predicted efficiencies of order 8%–9%.

The fixed surface tokamak plasma equilibria are analyzed by a variational steepest descent method employing global functions for the shift, ellipticity, and triangularity of the flux surfaces. The stationary and toroidally rotating axisymmetric tokamak equilibria have specific functionals from which the Grad-Shafranov equations can be derived as the equation for the @j (poloidal flux) variation. These functionals are minimized numerically to obtain the solutions. The global functions characterizing the plasma flux surface shift, ellipticity, and triangularity are conveniently given by a limited set of variational parameters which are obtained iteratively by the aforementioned minimization of the functional. In the case of the stationary equilibrium, the results obtained by the minimization of the functional are compared with those given by the pest code.

We examined now an ultraweak thermalized neutron field (UTNF) affects the structural transformation in DNA macromolecules at room temperature. IR-spectroscopy, electrophoresis, and filtration through nitrocellulose filter measurements revealed that UTNF irradiation with a fluence of F(n) - 1.0 - 3.7 x 10(7) n/cm2 (the absorbed dose as low as 10 - 50 microGy) can induce non negligible structural changes in DNA macromolecules in film as well as in an aqueous solution. These structural changes appear as a type of reversible conformational transition from the A-form to a disordered state, as well as through intermolecular cross-link formations and the generation of double-strand breaks.

Since the appeal by Brian Josephson at the meeting of the Nobel Laureates July 2004, it seems to be indicated to summarize the following serious, reproducible and confirmed observations on reactions of protons or deuterons incorporated in host metals such as paladium. Some reflections to Rutherford’s discovery of nuclear physics, the CockroftOliphant discovery of anomalous low energy fusion reactions and the chemist Hahn’s discovery of fission had to be included. Using gaseous atmosphere or discharges between palladium targets, rather significant results were seen e.g. from the “life after death” heat production of such high values per host atom that only nuclear reactions can be involved. This supports the earlier evaluation of neutron generation in fully reversible experiments with gas discharges hinting that a reasonable screening effect –preferably in the swimming electron layer –may lead to reactions at nuclear distances d of picometers with reaction probability times U of about megaseconds similar to the K-shell capture radioactivity. Further electrolytic experiments led to Low Energy Nuclear Reactions (LENR) where the involvement of pollution could be excluded from the appearance of very seldom rare earth elements. A basically new theory for DD cross sections is used to confirm the picometer-megasecond reactions of cold fusion. Other theoretical aspects are given from measured heavy element distributions similar to the standard abundance distribution, SAD, in the Universe with consequences on endothermic heavy nuclei generation, magic numbers and to quark-gluon plasmas.

We report the discovery of the new phenomenon of energetic alpha emission (up to 16.0MeV), and proton emission (∼1.7MeV), from a metal surface possessing a large affinity for hydrogen and loaded/excited by electrolysis, glow discharge or powerful laser. Various experiments on charged particle emission show a remarkable feature: all exhibit a similar yield per unit input energy of energetic alphas [one alpha particle per 10–15eV input energy/Pd(Ti) target atom], independent of the excitation power of delivering method (electrolysis, glow discharge or laser irradiation). The results suggest that the mechanism of energy transfer resulting in energetic particle emission in metal targets loaded with hydrogen is similar, despite the seemingly dissimilar excitation techniques.

The phenomenon of significant changes in the structure and physico-chemical properties of non-equilibrium solids exposed to an ultraweak thermalized neutron field (UTNF) is discussed. Such changes are accompanied by anomalous neutron capture. The UTNF involved is characterizing by a neutron density n /spl sim/ 10/sup -2/ /spl sim/ 10/sup -4/ cm/sup -3/ (the neutron flux in the range of 20 /spl sim/80 meV) corresponding to absorbed doses as low as 1-10 /spl mu/Gy. Changes in atomic (molecular) structure as well as the strong micro and macro plastic deformations in the various types of non-equilibrium solids (metal-hydrogen systems, ferroelectrics, ion and covalent crystals, polymers, DNA macromolecules) have been observed. These results provide important new insight into basic physics and biological phenomena that can occur in UTNF under non-equilibrium condition.

Ion injection into the Inertial Electrostatic Confinement (IEC) fusion power plant used in the design of the high performance Fusion Ship II (Burton et al., 2003) is a key technological issue for development of this concept. This paper discusses the design and initial experiments with a radiofrequency (RF) ion gun designed for this purpose. The RF Gun design described here was found to have some important advantages over other ion gun designs: simple construction, a higher extraction efficiency; 10 ((mA/cm2)/W), a lower divergence; 10.8 ± 0.36 mrad, and a very intensive ion flux; 6 × 1018 ions/(cm2.sec) measured at 0.27 Pa.

Previous studies have shown that Single-State-to-Orbit (SSTO) vehicle propellant can be reduced by Magnets-Hydro-Dynamic (MHD) processes that minimize airbreathing propulsion losses and propellant consumption during atmospheric flight, and additional reduction in SSTO propellant is enabled by Inertial Electrostatic Confinement (IEC) fusion, whose more energetic reactions reduce rocket propellant needs. MHD airbreathing propulsion during an SSTO vehicle’s initial atmospheric flight phase and IEC fusion propulsion during its final exo-atmospheric flight phase is therefore being explored. Accomplished work is not yet sufficient for claiming such a vehicle’s feasibility. But takeoff and propellant mass for an MHD airbreathing and IEC fusion vehicle could be as much as 25 and 40 percent less than one with ordinary airbreathing and IEC fusion; and as much as 50 and 70 percent less than SSTO takeoff and propellant mass with MHD airbreathing and chemical rocket propulsion.

A collimated proton detector has been developed for spatial resolved proton measurements in inertial‐electrostatic plasma confinement (IEC) fusion experiments. These are the first proton measurements used to infer potential well profiles on an IEC device. This paper describes a new technique for investigating the existence of multiple potential wells inside IEC devices. Analysis of the observed proton energy and source profile indicates that (for a 12‐mA cathode current, a 30‐kV cathode voltage in a 4‐mTorr D2 background) predominantly beam‐background fusion occurs. Computer simulation suggests that a positive space charge potential approximately half that of the applied voltage is formed inside the cathode. These results establish the first measurement of a positive potential well structure inside an ion‐injected IEC device.

Concept Studies have shown the IEC to be one of the most attractive approaches to fusion propulsion, provided the physics and technology involved can be scaled-up to high power levels. A key step involves development of a pulsed IEC that can obtain high ion currents along with good ion confinement. Results from initial pulsed IEC experiments are described here. The obtainment of a D-D fusion neutron yield of 8×108 n/s at a peak pulse current of 17 A demonstrates that the dynamic formation of the required accelerating fields with the IEC discharge is possible. A next step involves improvement in confinement.

A hybrid “nuclear light bulb” gaseous core reactor that can radiantly transfer energy to a propellant or alternately activate laser action is proposed for advanced space missions. The propellant mode would be employed in the phases of the mission requiring a higher thrust. However, for the bulk of the travel, the propellant would be turned off and the ultrahigh specific impulse laser mode of operation would be employed. The concept is reviewed, research and development issues are identified, and steps necessary for a feasibility demonstration are discussed.

The biased probe, as a unique extension of the Langmuir probe, offers several advantages in measuring the charged‐particle flux versus position in a beam‐dominated plasma such as encountered in the spherical electrostatic inertial confinement (SEIC) device. The probe operates in a non‐Maxwellian and locally non‐neutral plasma, where the Debye length is large compared to the probe itself. Its conical particle acceptance extension minimizes the measurement error caused by the distortion of the SEIC potential structures. Either the ion or electron flux can be measured using the proper bias on its inner collecting element.

Nuclear Pumped Lasers (NPLs) offer unique advantages for a variety of high-power laser applications. NPLs receive pump energy from nuclear reactions created by neutrons entering the laser medium. This technique offers a high specific power and compactness of nuclear energy-sources that pump a large volume of the laser-active medium. The unique large excitation volume results in a high energy output. In addition, the direct use of neutrons from a fission reactor avoids intermediate energy conversion steps. The concept explored here extracts both electrical and laser outputs from a single “hybrid” or dual purpose reactor. Simultaneous electrical production helps defray the high cost of such a facility, making space power beaming more practical.

This report describes a study of nuclear power economics in Russia. It addresses political and institutional background factors which constrain Russia's energy choices in the short and intermediate run. In the approach developed here, political and institutional factors might dominate short-term decisions, but the comparative costs of Russia's fuel-cycle options are likely to constrain her long-term energy strategy. To this end, the authors have also formulated a set of policy questions which should be addressed using a quantitative decision modeling which analyzes economic costs for all major components of different fuel cycle options, including the evolution of uranium prices.

Optical inhomogeneities in the laser gas (caused by nonuniform pumping) prevent efficient extraction of laser energy in Nuclear Pumped Lasers (NPLs). We propose the combined wall and volume pumping scheme for reduction of the optical inhomogeneities. However, this scheme represents a delicate balance due to the fact that the lasing kinetics might be affected. Results from the investigation of combined pumping as a control technique are presented.

Radiation damage of the final optical components in an Inertial Confinement Fusion (ICF) reactor is a crucial issue for development of a laser‐fusion reactor. To some extent, this problem will be encountered in the National Ignition Facility (NIF), but there, the integrated radiation dose will be considerably less than that encountered in a future reactor. This extremely harsh radiation environment necessitates shielding the ICF optics from direct neutron and x‐ray bombardment. Several approaches have been suggested, such as the use of grazing incidence metal mirrors or fused silica wedge deflectors. While metal mirrors can withstand a larger radiation dose, their focusing qualities pose problems. Therefore wedge deflectors, originally suggested by Lawrence Livermore National Laboratory (LLNL) staff, represent a promising alternative. Radiation hardening of the fused silica deflectors using a new combined thermal/optical annealing approach is examined here as a method to maintain transmission quality duri...

To date, nuclear pumped lasers (NPLs) have been driven by neutrons from pulsed research fission reactors. However, future applications using either a Magnetic Confinement Fusion (MCF) neutron source or an Inertial Confinement Fusion (ICF) source appear attractive. One unique combination proposed earlier would use a neutron feedback NPL driver in an ICF power plant. 14‐MeV D‐T neutrons (and 2.5‐MeV D‐D neutrons) provide a unique opportunity for a neutron recoil pumped NPL. Alternatively, these neutrons can be thermalized to provide thermal‐neutron induced reactions for pumping. Initial experience with a fusion‐pumped NPL can possibly be obtained using the D‐T burn experiments in progress/planning at the Tokamak Fusion Test Reactor (TFTR) and Joint European Torus (JET) tokamak devices or at the planned National Ignition Facility (NIF) high‐gain ICF target experimental facility. With neutron fluxes presently available, peak thermalized fluxes at a test laser in the shield region could exceed 1014 n/cm2/sec. Several low‐threshold NPLs might be utilized in such an experiment, including the He‐Ne‐H2 NPL and the Ar‐Xe NPL. Experimental set‐ups for both the tokamak and the NIF will be described.

Inertial Electrostatic Confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P. T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams.Gridded IEC systems have demonstrated neutron yields as high as 2*1010 neutron/sec. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application.Atomic physics effects strongly influence the performance of all of these systems. Important atomic effects include elastic scattering, ionization, excitation, and charge exchange. This paper discusses how an IEC system is influenced by these effects and how to design around them. Theoretical modeling and experimental results are presented.

Beam focusing (thermal blooming) is a major issue in Nuclear Pumped Lasers (NPLs), since it can cause beam distortions. The phenomenon is due to nonuniform pumping in the gas medium. In order to minimize the focusing effect while still achieving high power deposition, the use of a combined wall and volume source is proposed. The design parameters for a combined source laser that minimizes self‐focusing are determined using theoretical modeling that is experimentally benchmarked.

The lasing on infrared (IR) transitions of Xe atoms, resulting in direct nuclear pumping, was first reached in 1975 by a U. of Florida team in collaboration with scientists from Los Alamos National Laboratory. However, the IR xenon nuclear pumped laser (NPL) is still being intensively studied, because of its record output characteristics. The fact that the most transparent window in the earth’s atmosphere corresponds to the main intense laser line wavelength. λ=1.732 μm, also adds to interest in investigating this laser. The active medium of the laser is a mixture of rare gases, which eliminates the problem of degradation of the active mixture by undesirable chemical reactions.

There is considerable demand in the scientific community for a neutron generator with an output of 106–108 neutrons/second (n/s) that can be switched on or off, emit fusion neutrons, be self‐calibrating, and offer portable operation. An Inertial Electrostatic Confinement (IEC)‐based neutron generator is proposed to meet these needs.In an IEC device, ion beams are injected into a spherical vacuum vessel containing one or more sets of spherical wire grids. A high fusion rate is generated in a dense plasma region created in the center of the innermost grid by intersecting ion beams and the associated potential well structure. Here, we describe a unique configuration, termed the IECGD, where a gaseous discharge in a single‐gridded device serves as the ion source. Operation in the newly discovered “Star” discharge mode maximizes the effective grid transmission factor for ions. This configuration, then, provides a simple, rugged, low‐cost fusion neutron source, operating in the 106 D‐D n/s or 108 D‐T n/s range. The extension to an intense MeV proton source is also possible.Experimental results for the IECGD are presented, with a discussion of corresponding theoretical studies using a Vlasov‐Poisson solver (IXL) and an electrostatic particle‐in‐cell code (PDS1).

Full three-dimensional maps of the helicon wave magnetic field are measured. Agreement between the measured and predicted values for the helicon wavelength is discussed and discrepancies are attributed to interpretation of the three-dimensional wave. Magnetic induction probe measurements in XYZ space reveal the helicon wave bz field has both an axial and azimuthal component. Neglecting the azimuthal component underestimates the three-dimensional wave helix by at least a factor of ~2πr, yielding an oversimplified two-dimensional projection. When the wave's azimuthal component is considered, agreement with numerically predicted wavelength values is shown to be within 35%, whereas greater than 100% differences are found when only the two-dimensional wavelength is measured.

‘‘Cold Fusion’’ experiment have been performed elsewhere using a dense plasma focus machine. It is the purpose of an oncoming study at the UI to reproduce and extend these experiments using a similar device at the University of Illinois. The Illinois facility is described as well as the technique that will be used. Extensions are suggested.

Results to date of an experimental study of the nuclear-induced excitation of the excimer XeBr are presented. The excitation source used was the reaction 10B(n, 4He)7Li + 2.8 MeV. Pressures up to 800 torr Xe/Br/Ar were studied, using Br2, CHBr3, and BBr3 as bromine donors. Gas fill mix ratios were varied to maximize the excimer line output at 282 nm. Absolute fluorescence efficiencies (light output at 282 nm/energy deposited in cell) were measured, with an optimum of 25–38% found. The application of this fluorescence in the development of an atomic iodine photodissociation laser is discussed.

Together with space-charge neutralization, ionization and charge exchange in the heavy ion beam fusion (HIBF) chamber can change beam quality and final focusing. Our research here supports simulation of these interactions through exploring theoretical approaches and developing improved models. This study is focused on the multi-electron processes which play an important role for these low-charged high-energy heavy ions. An improved classic trajectory Monte Carlo model and corresponding codes have been developed to simulate the heavy ion-atom collisions, which require intensive computations to solve many-body Hamiltonian Equations. Currently the results from the ion Xeq+ (q = 1-18) colliding with Xe gas show that multi-electron effects are significant, and this cross section can reach about 40% of the total. The improved code is expected to be an integral part of a plasma simulation package designed to study the atomic effects in beam transport and focusing in HIBF using plasma neutralization techniques. This should help provide improved physical insight into current HIBF experiments and future studies.

A new e‐beam probe is developed to study the potential structure inside a SEIC device [G. H. Miley et al., Fusion Technol. 19, 840 (1991)]. The device has a spherical grid negatively biased inside a spherical vacuum chamber. Ions oscillate through the highly transparent grid, forming a single potential well inside the cathode. The potential in turn attracts electrons from ionization of background gas. The measurement of this complex potential profile is the objective of this work. The e‐beam probe offers advantages over the e‐emitting probes and the laser heterodyne method. It minimizes perturbations (versus a physical probe) and detects smaller charge density variations than possible with laser techniques. The present e‐beam probe utilizes a higher voltage and a modified focus compared to the earlier version used by Swanson [Swanson et al., Phys. Fluids 16, 1939 (1973)]. The characteristic e‐beam deflection patterns observed are compared to predictions from an impulse approximation model.

New studies of gas-proportional scintillation counters have been performed using a large alpha source, reasonable spectral resolution (< 25-k), and including the strong near-infrared transitions in noble gases excluded in all previous studies. The results indicate that several new gas mixtures show promise for detectors to measure the neutron fluxes in a reactor over a wide range of values and in many nuclear physics applications where fast response and good energy resolution are desired. When used with an isotopic source the device can be used as a portable, variable-intensity light source or to detect trace amounts of atmospheric contaminants such as CO, NO, and Hg. The work also has provided useful data for laser systems pumped by ionizing radiation as well as for the operation of plasma display panels.

A 6150‐A He‐Hg laser, pumped solely by the 1n (10B,α) 7Li nuclear reaction, has been achieved using the Sandia SPRII reactor. The optimum conditions for lasing were 600 Torr total pressure with 2.5 mTorr Hg partial pressure, with a threshold for lasing of ∼1016 n/cm2 sec. This is the first visible‐wavelength laser having nuclear energy as its only source of excitation.

The modeling of the steady-state fusion-born alpha particle distribution in a mirror loss-cone is investigated. The Legendre function expansion and diffusion-front methods are reviewed and examined. The diffusion-front method is shown to be am accurate and efficient method are alpha-loss-cone instability calculations in a tandem mirror fusion device.

The anisotropic loss‐cone distribution of fusion‐born alpha particles in a mirror system is capable of destabilizing low‐frequency plasma waves. A one‐and‐one‐half‐dimensional quasilinear diffusion model is developed to study the nonlinear evolution of the alpha distribution function resulting from enhanced diffusion in velocity space and radial position driven by the unstable Alfven wave. It is found that pitch‐angle scattering of the resonant alphas into the loss cone causes significant losses while radial losses are negligible for a reactor‐size plasma. For a typical tandem‐mirror reactor, the alpha plasma heating is greatly reduced and ignition in the central cell cannot be achieved.

The first successful modeling of an impurity-type nuclear pumped laser (NPL) (i.e., one that employs trace densities of the lasing species in a noble gas buffer), atomic carbon at 1.45 ..mu..m, was achieved. Such NPLs are important due to their low flux threshold and quasi-steady-state oscillation. The atomic carbon NPL is unique in that time delays up to 5 ms are observed between the laser signal and the excitation pulse in helium + CO/sub 2/ mixtures while no delay is observed in helium + CO. Using a kinetic model in conjunction with an experimental program, we show that this difference in delay arises from slow dissociation of CO/sub 2/ to form CO. Significantly, the model also successfully simulates electrical pumping of He-CO or CO/sub 2/ mixtures.

Electrical arcing from surfaces is recognized as a potentially deleterious source of plasma impurities for next generation fusion devices. Surface coatings and/or surface conditioning techniques can be applied to reduce the amount of such arc generated impurity atoms. In order to investigate the arcing phenomenon and to assess the arcing performance of various coatings and coating techniques, a unique experimental facility is being developed. This dual purpose facility, developed around an existing ion plating system, allows for the convenient joint studies of arcing phenomenon and coating deposition processes. Completed work includes the construction of an arcing test fixture for study of coating performance in a ‘‘glow discharge to biased surface’’ configuration, and the deposition of selected coating materials using ion plating techniques. Work is continuing toward the development of arc testing and diagnostic instrumentation.