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Accelerator and final focus model for an induction Linac based HIF system study

Description: An overview of the assumptions and models incorporated in the ongoing Induction-Linac-based, HIF System Assessment is presented. Final transport, compression and final focus pose constraints which form a critical link between the accelerator and target requirements. A recent analysis has shown that system costs may be considerably reduced by the use of multiply charges ions. The assumptions underlying this direction are described.
Date: July 1, 1986
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Determination of the radius of a self-pinched beam from its energy integral

Description: The total transverse energy (kinetic plus potential) of a self-pinched beam may be used to predict the final equilibrium radius when the beam is mismatched at injection. The dependence of potential energy on the current profile shape is characterized by a dimensionless parameter C(z), variations of which are correlated with the change of emittance.
Date: January 2, 1980
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Velocity distribution in a pinched beam

Description: An explicity procedure is given for distributing transverse velocities to simulate a self pinched beam of specified density profile. The flat top, Bennett and Gaussian profiles are worked examples.
Date: September 17, 1979
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Transport of intense ion beams. [HIBALL II]

Description: The maximum transportable current for an ion beam is determined by considerations of focal strength, space charge equilibrium and stability, structural practically and emittance. These factors are described within the context of a heavy ion driver for Inertial Confinement Fusion. Recent supporting results from particle-in-cell simulations and transport experiments will be described.
Date: June 1, 1986
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Resistance-driven bunching mode of an accelerated ion pulse

Description: Amplification of a longitudinal perturbation of an ion pulse in a linear induction accelerator is calculated. The simplified accelerator model consists only of an applied field (E/sub a/), distributed gap impedance per meter (R) and beam-pipe capacity per meter (C). The beam is treated as a cold, one-dimensional fluid. It is found that normal mode frequencies are nearly real, with only a very small damping rate proportional to R. This result is valid for a general current profile and is not restricted to small R. However, the mode structure exhibits spatial amplification from pulse head to tail by the factor exp(RCLv/sub o//2), where L is pulse length and v/sub 0/ is drift velocity. This factor is very large for typical HIF parameters. An initially small disturbance, when expanded in terms of the normal modes, is found to oscillate with maximum amplitude proportional to the amplification factor.
Date: October 16, 1981
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Model of beam head erosion

Description: An analytical model of beam head dynamics is presented, leading to an estimate of the erosion rate due to the combined effects of Ohmic dissipation and scattering. Agreement with the results of a computer simulation and detailed one-dimensional computations is good in all respects except for the scaling of the erosion rate with net current.
Date: August 8, 1980
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Radiation damping of betatron oscillations

Description: The emission of synchrotron radiation damps the incoherent betatron oscillations of a pinched beam, causing its radius to shrink. However, the rate of shrinkage is small compared with the rate of expansion caused by scattering for typical propagation parameters.
Date: April 20, 1982
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Model equations for high current transport

Description: The use of distribution functions to model transverse beam dynamics is discussed. Emphasis is placed on envelope equations, moments, the Vlasov equation, and the Kapchinski-Vladimirskij distribution. 10 refs.
Date: June 1, 1985
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

High temperature experiment for accelerator inertial fusion

Description: The High Temperature Experiment (HTE) is intended to produce temperatures of 50 to 100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy, number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) target temperature and uses limitations due to particle range, beamlet perveance, and target disassembly to bound the allowable values of mass number (A) and energy (E). An accelerator model is then applied to determine the minimum length accelerator, which is a guide to total cost. The accelerator model takes into account limits on transportable charge, maximum gradient, core mass per linear meter, and head-to-tail momentum variation within a pulse.
Date: May 1, 1985
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

P Division monthly report, January 1950

Description: This progress report discusses the activities of the P Division for the month of January 1950. The B, D, F and H pilan operated throughout the month except for outages listed under Area Activities. Power levels were as follow: B pile -- 275 megawatts (MW) D pile -- 305 MW, F pile -- 275 MW increased to 305 MW during the month, and H pile -- 275 MW increased to 330 MW during the month. The piles operated with a time operated'' efficiency of 88.8%. A total of 53.07 tons of metal at an average of 91.2% of the current goal concentration was discharged from the piles during the month. A new record canning yield of 93.9% for 4 inch canned slugs was established during January.
Date: February 6, 1950
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

P Division monthly report, November 1948

Description: This progress report discusses activities at the P Division for the month of November 1948. All piles operated at 275 megawatts (MW) throughout the month except for outages listed under Area Activities in this report and except that F Pile operated at a reduced level during the first half of the month. This operation at reduced level was incident to the leaking process tube reported last month. A total of 81.4 tons of metal was discharged from the piles during the month. The 300 Area canned a total of 150 tons of acceptable slugs during the month to establish a new production record. On November 29 the operating schedule for the Melt Plant was changed from a three-shift to a two-shift, six-day week schedule. The backlog of material largely had been worked off and the new schedule is adequate for processing the current accumulation of scrap.
Date: December 20, 1948
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Effects of thermomechanical treatment on phase stability and swelling in alloy D9

Description: Improvement in the swelling of AISI 316 may be achieved through adjustments to levels of Ni, Cr, Mo, Ti, and Si. Effort is concerned with optimizing the composition range for greater phase stability and improving alloy homogeneity. Irradiation response to variations in thermomechanical treatment (TMT) was studied. Swelling peak is suppressed by TMT which produces a high dislocation density or by increasing the solution treatment temperature to 1200/sup 0/C. (FS)
Date: January 1, 1979
Creator: Lee, E.H. & Rowcliffe, A.F.
Partner: UNT Libraries Government Documents Department

Radiation damage and phase instability in irradiated stainless steel

Description: A 316 stainless steel, LS1A, with greater than nominal levels of silicon and titanium has been developed which exhibits high resistance to swelling under ion irradiation. The origin of this swelling resistance and the roles of silicon and titanium have been investigated in the current study.
Date: January 1, 1983
Creator: Kenik, E.A. & Lee, E.H.
Partner: UNT Libraries Government Documents Department

Heavy ion driven LMF design concept

Description: The USA Department of Energy has conducted a multi-year study of the requirements, designs and costs for a Laboratory Microfusion Facility (LMF). The primary purpose of the LMF would be testing of weapons physics and effects simulation using the output from microexplosions of inertial fusion pellets. It does not need a high repetition rate, efficient driver system as required by an electrical generating plant. However there would be so many features in common that the design, construction and operation of an LMF would considerably advance the application of inertial confinement fusion to energy production. The DOE study has concentrated particularly on the LMF driver, with design and component development undertaken at several national laboratories. Principally, these are LLNL (Solid State Laser), LANL (Gas Laser), and SNLA (Light Ions). Heavy Ions, although considered a possible LMF driver did not receive attention until the final stages of this study since its program management was through the Office of Energy Research rather than Defense Programs. During preparation of a summary report for the study it was decided that some account of heavy ions was needed for a complete survey of the driver candidates. A conceptual heavy ion LMF driver design was created for the DOE report which is titled LMC Phase II Design Concepts. The heavy ion driver did not receive the level of scrutiny of the other concepts and, unlike the others, no costs analysis by an independent contractor was performed. Since much of heavy ion driver design lore was brought together in this exercise it is worthwhile to make it available as an independent report. This is reproduced here as it appears in the DOE report.
Date: August 1, 1991
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Particle in cell simulations of disruption

Description: An improved numerical particle simulation code has been developed to study the electrodynamical interaction of colliding electron and positron beams. Contrary to previously reported work (which was in error due to a coding mistake), it is found that the maximum enhancement in luminosity due to the mutual pinch effect can exceed a factor of 6 for beams with Gaussian radial profiles and approaches 5 for uniform profiles. These new results are in much better agreement with those originally found by R. Hollebeek.
Date: June 1, 1987
Creator: Fawley, W.M. & Lee, E.P.
Partner: UNT Libraries Government Documents Department

Analysis of NSWC quasi-static compaction data for porous beds of ball powder, melamine, and Teflon, using structural compaction model

Description: A structural compaction model is used to correlate NSWC quasi-static compaction data on porous beds of six (6) different materials, i.e., four (4) ball powders, melamine, and Teflon. Initial densities of the porous beds ranged from 44 percent solid theoretical maximum density (TMD) to 70 percent TMD. Maximum compacted densities were about 90 percent TMD except for Teflon which was compacted to approximately 98 percent TMD. Pressures calculated by the model, plotted as a function of percent TMD, agree well with the NSWC data.
Date: April 6, 1983
Creator: Weston, A.M. & Lee, E.L.
Partner: UNT Libraries Government Documents Department

Heavy-Ion Fusion System Assessment Project quarterly status report, January-March 1985

Description: A computer model of an accelerator system is a necessary ingredient in estimating the cost of construction and operation of an ion-driven ICF power plant. The LBL computer program LIACEP (Linear Induction Accelerator Cost Evaluation Program) is used to estimate the cost and efficiency of a heavy ion induction linear accelerator as a function of the ion mass, charge and energy for a specified beam output energy, power and pulse repetition frequency. In addition to estimating the accelerator system cost and efficiency, LIACEP can be used to identify the components and materials that have a high leverage on the cost and efficiency of the accelerator system. These high leverage items are logical areas for research and technology development to reduce the cost and increase the efficiency of the accelerator system.
Date: June 1, 1985
Creator: Lee, E.P.; Hovingh, J. & Faltens, A.
Partner: UNT Libraries Government Documents Department

Fringe fields for the N channel permanent magnet array

Description: Analytical expressions are obtained for fringe field multipoles of an N channel permanent magnet quadrupole array. It is assumed that the system of magnetic wedges starts at some transverse (x, y) plane located at z = 0, and it continues to a magnet length z = l, where it stops. The iron yoke continues to z = {+-} {infinity}, but it will be shown that only a small overhang is actually required to maintain the quadrupole and translational symmetries. Recall the 2-d solution for the magnetic potential (H = {del}{phi}): {phi}{sub 2} = A [(x-x{sub i}){sup 2} - (y-y{sub i}){sub 2}], where A = -M{sub 0}/4b, M{sub 0} is the remnant field of the wedges, and (x{sub i}, y{sub i}) are the coordinates for the center of box (i). Boxes have dimensions 2b x 2b and alternate between vacuum fill (for beams) and magnetic wedge fill. The 2-d system looks like a portion of an infinite transverse lattice with periodicity lengthy = 4b in both the x and y directions. For the magnetic potential {phi}, the periodicity length is 2b.
Date: April 1, 1996
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

The beam envelope equation-systematic solution for a periodic quadrupole lattice with space charge

Description: Many approximate solutions for matched beam envelope functions with space charge have been developed; they generally have errors of 2-10% for the parameters of interest and cannot be reliably improved. The new, systematic approach described here provides the K-V envelope functions to high accuracy as a power series in the quadrupole gradient. A useful simplification results from defining the sum and difference of the envelope radii; S = (a+b)/2 varies only slightly with distance z along the system axis, and D = (a-b)/2 contains most of the envelope oscillations. To solve the coupled equations for S and D, the quadrupole strength K(z) is turned on by replacing K with {alpha}K{sub 1} and letting {alpha} increase continuously from 0 to 1. It is found that S and D may be expanded in even and odd powers of {alpha}, respectively. Equations for the coefficients of powers of {alpha} are then solved successively by integration in z. The periodicity conditions and tune integration close the calculation. Simple low order results are typically accurate to 1% or better.
Date: April 1, 1995
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Heavy ion driven LMF design concept. Revised

Description: From 1988 to 1991, the US Department of Energy conducted a study of the requirements, designs and costs for a Laboratory Microfusion Facility (LMF). The primary purpose of the LMF would be testing of weapons physics and effects simulation using the output from microexplosions of inertial fusion targets. It does not need a high repetition rate, efficient driver system as required by an electrical generating plant; however there would be so many features in common that the design, construction and operation of an LMF would considerably advance the application of inertial confinement fusion to energy production. The DOE study concentrated particularly on the LMF driver, with design and component development undertaken at several national laboratories. Heavy Ions, although considered a possible LMF driver, did not receive attention until the final stages of this study since its program management was through the Office of Energy Research rather than Defense Programs. However, during preparation of the summary report for the study it was decided that an account of heavy ions was needed for a complete survey of the driver candidates. The conceptual heavy ion LMF driver design created for the DOE report did not receive the level of scrutiny of the other driver concepts and, unlike the others, no cost analysis by an independent contractor was performed.
Date: July 1, 1995
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

The beam envelope equation -- Systematic solution for a FODO lattice with space charge

Description: Many approximate solutions for matched beam envelope functions with space charge have been developed; they generally have efforts of 2--10% for the parameters of interest and cannot be reliably improved. The new, systematic approach described here provides the K-V envelope functions to arbitrarily high accuracy as a power series in the quadrupole gradient. A useful simplification results from defining the sum and difference of the envelope radii; S = (a+b)/2 varies only slightly with distance z along the system axis, and D = (a-b)/2 contains most of the envelope oscillations. To solve the coupled equations for S and D, the quadrupole strength K(z) is turned on by replacing K with {alpha}K{sub 1} and letting {alpha} increase continuously from 0 to 1. It is found that S and D may be expanded in even and odd powers of {alpha}, respectively. Equations for the coefficients of powers of {alpha} are then solved successively by integration in z. The periodicity conditions and tune integration close the calculation. Simple low order results are typically accurate to 1% or better.
Date: May 1, 1995
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Constitutive model for porous materials

Description: A simple pressure versus porosity compaction model is developed to calculate the response of granular porous bed materials to shock impact. The model provides a scheme for calculating compaction behavior when relatively limited material data are available. While the model was developed to study porous explosives and propellants, it has been applied to a much wider range of materials. The early development of porous material models, such as that of Hermann, required empirical dynamic compaction data. Erkman and Edwards successfully applied the early theory to unreacted porous high explosives using a Gruneisen equation of state without yield behavior and without trapped gas in the pores. Butcher included viscoelastic rate dependance in pore collapse. The theoretical treatment of Carroll and Holt is centered on the collapse of a circular pore and includes radial inertia terms and a complex set of stress, strain and strain rate constitutive parameters. Unfortunately data required for these parameters are generally not available. The model described here is also centered on the collapse of a circular pore, but utilizes a simpler elastic-plastic static equilibrium pore collapse mechanism without strain rate dependence, or radial inertia terms. It does include trapped gas inside the pore, a solid material flow stress that creates both a yield point and a variation in solid material pressure with radius. The solid is described by a Mie-Gruneisen type EOS. Comparisons show that this model will accurately estimate major mechanical features which have been observed in compaction experiments.
Date: January 1, 1982
Creator: Weston, A.M. & Lee, E.L.
Partner: UNT Libraries Government Documents Department