A new approach to modeling linear accelerator systems (open access)

A new approach to modeling linear accelerator systems

A novel computer code is being developed to generate system level designs of radiofrequency ion accelerators with specific applications to machines of interest to Accelerator Driven Transmutation Technologies (ADTT). The goal of the Accelerator System Model (ASM) code is to create a modeling and analysis tool that is easy to use, automates many of the initial design calculations, supports trade studies used in accessing alternate designs and yet is flexible enough to incorporate new technology concepts as they emerge. Hardware engineering parameters and beam dynamics are to be modeled at comparable levels of fidelity. Existing scaling models of accelerator subsystems were used to produce a prototype of ASM (version 1.0) working within the Shell for Particle Accelerator Related Code (SPARC) graphical user interface. A small user group has been testing and evaluating the prototype for about a year. Several enhancements and improvements are now being developed. The current version of ASM is described and examples of the modeling and analysis capabilities are illustrated. The results of an example study, for an accelerator concept typical of ADTT applications, is presented and sample displays from the computer interface are shown.
Date: July 22, 1994
Creator: Gillespie, G. H.; Hill, B. W. & Jameson, R. A.
Object Type: Article
System: The UNT Digital Library
Anisotropy and spatial variation of relative permeability and lithologic character of Tensleep Sandstone reservoirs in the Bighorn and Wind River basins, Wyoming. Third quarterly technical progress report, April 1, 1994--June 30, 1994 (open access)

Anisotropy and spatial variation of relative permeability and lithologic character of Tensleep Sandstone reservoirs in the Bighorn and Wind River basins, Wyoming. Third quarterly technical progress report, April 1, 1994--June 30, 1994

This multidisciplinary study is designed to provide improvements in advanced reservoir characterization techniques. This goal is to be accomplished through: (1) an examination of the spatial variation and anisotropy of relative permeability in the Tensleep Sandstone reservoirs of Wyoming; (2) the placement of that variation and anisotropy into paleogeographic, depositional, and diagenetic frameworks; (3) the development of pore-system imagery techniques for the calculation of relative permeability; and (4) reservoir simulations testing the impact of relative permeability anisotropy and spatial variation on Tensleep Sandstone reservoir enhanced oil recovery. Concurrent efforts are aimed at understanding the spatial and dynamic alteration in sandstone reservoirs that is caused by rock-fluid interaction during CO{sub 2}-enhanced oil recovery processes. The work focuses on quantifying the interrelationship of fluid-rock interaction with lithologic characterization in terms of changes in relative permeability, wettability, and pore structure, and with fluid characterization in terms of changes in chemical composition and fluid properties. This work will establish new criteria for the susceptibility of Tensleep Sandstone reservoirs to formation alteration that results in change in relative permeability and in wellbore scale damage. This task will be accomplished by flow experiments using core material; examination of regional trends in water chemistry; examination of local …
Date: July 22, 1994
Creator: Dunn, T. L.
Object Type: Report
System: The UNT Digital Library
Increasing the retained dose by plasma immersion ion implantation and deposition (open access)

Increasing the retained dose by plasma immersion ion implantation and deposition

The retained dose of ions can be increased by Plasma Immersion Ion Implantation and Deposition (PIIID). A substrate is immersed in a metal or carbon plasma and a negative repetitively pulsed bias voltage is applied. During the pulses, an electric sheath is formed around the substrate and ions are accelerated through the sheath and implanted into the substrate. Direct and recoil ion implantation and sputtering take place during the pulses whereas low-energy deposition occurs between the pulses. The condensable plasma can be produced using a cathodic arc plasma source combined with a magnetic macroparticle filter. PIIID can be applied to perform fast high-dose implantations or to deposit thin films with broad intermixing at the film-substrate interface. The bias voltage duty cycle can be tuned to sputter away the film deposited during pulse off-time (similar to the method of sacrificial layer). We have simulated the PIIID process using the Monte Carlo code T-DYN 4.0. This code allows a calculation of the dose-dependent depth profile for a process with deposition and implantation phases, taking sputtering into account. Predicted retained doses and experimentally obtained retained doses measured by Rutherford backscattering spectrometry are compared.
Date: July 22, 1994
Creator: Anders, A.; Anders, S.; Brown, I. G. & Yu, Kin M.
Object Type: Article
System: The UNT Digital Library
Global confinement analysis. Final report, May 1, 1992--April 31, 1994 (open access)

Global confinement analysis. Final report, May 1, 1992--April 31, 1994

A brief description of the task: (1) Analyze confinement databases to development predictions for ITER, and identify and quantify major sources of continement uncertainty. (2) Determine the parametric dependencies of the temperature and density profiles for reactor relevant plasmas.
Date: July 22, 1994
Creator: Riedel, K. S.
Object Type: Report
System: The UNT Digital Library
Texas Pecan Pest Management Newsletter, Volume 94, Number 7, July 1994 (open access)

Texas Pecan Pest Management Newsletter, Volume 94, Number 7, July 1994

Newsletter focusing on pecan disease and pest control in Texas, including prevention, identification, treatment, and educational opportunities.
Date: July 22, 1994
Creator: Texas Agricultural Extension Service
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History