D0 Silicon Upgrade: Thermally Induced Bowing in a 3-CHIP Ladder (open access)

D0 Silicon Upgrade: Thermally Induced Bowing in a 3-CHIP Ladder

The end of the 3 chip ladder, shown below, consists of silicon mounted on a piece of beryllium which is adhered to the cooling channel. Outboard of the cooling channel is a region of ladder composed primarily of silicon/beryllium. Operation and cooling of the ladder results in a change in temperature from the assembly temperature, which will result in deflections due to the difference in expansion coefficients of the two materials, otherwise known as 'bi-metal' bowing. The goal of this note is to present a design of the beryllium plate on the underside of the ladder which reduces the thermally induced bow to a reasonable deflection. This region of ladder will see a fairly large temperature gradient during detector operation due to the heat load of the transceivers on the ladder end. Expected temperatures range between 22 C on the ladder end to 9.5 C near the cooling channel for a coolant temperature of 5 C. The coolant temperature may be as low as -5 C, so we may estimate a lower limit on the ladder temperatures to be 10 C cooler, ranging from 12 C on the ladder end to -0.5 C near the bulkhead (assumes negligible convection from …
Date: August 22, 1994
Creator: Ratzmann, Paul
Object Type: Report
System: The UNT Digital Library
Unique microchannel plate process doubles MCPI resolution (open access)

Unique microchannel plate process doubles MCPI resolution

Applying a dielectric layer to the output of a microchannel plate (MCP) has allowed the screen voltage of a sealed microchannel-plate intensifier tube (MCPI) to be raised to over 10 kV, producing a field strength of 36 kV/mm without any detectable field emission or breakdown of the MCP/screen gap. Tube resolution exceeded 16 lp/mm at 50% modulation. Breakdown is higher in a dielectric than in a vacuum. In a concept being patented by Gary Power, a few-{mu}m-thick layer of a dielectric was sputtered onto the output surface of an 18-mm MCP, which was incorporated into a tube under a contract for four tube starts. This process is applicable to any device incorporating a proximity-focused MCP and screen, including streak tubes and gated MCP x-ray imagers. Other improvements discussed include a patented use of a collimator for eliminating the electrons that are elastically scattered from the screen. This method also provides for further improvements in screen gap limited resolution to any desired degree by eliminating electrons with high transverse energy. This occurs at the expense of output brightness, which can be recovered through an appropriate increase in screen voltage.
Date: August 22, 1994
Creator: Thomas, S. & Power, G.
Object Type: Article
System: The UNT Digital Library
Observation of nonlinear neoclassical {nabla}{sub p}-driven tearing modes in TFTR (open access)

Observation of nonlinear neoclassical {nabla}{sub p}-driven tearing modes in TFTR

A quantitative comparison is made between the tearing-type modes observed supershot plasmas and the nonlinear, neoclassical pressure gradient ({nabla}{sub p}) driven tearing mode theory. Good agreement is found on the nonlinear magnetic island evolution of a single helicity mode (m/n = 3/2, 4/3 or 5/4, where m and n are the poloidal and toroidal mode numbers, respectively). Statistical data on the island width and growth rate are also found to be consistent with this theory. The results imply that the supershot plasmas are the classical current-driven tearing modes.
Date: August 22, 1994
Creator: Chang, Z.; Callen, J. D.; Hegna, C. C.; Fredrickson, E. D.; Budny, R. V.; McGuire, K. M. et al.
Object Type: Report
System: The UNT Digital Library
Super heated vapor drying process (open access)

Super heated vapor drying process

The invention studied pertains to a super heated vapor drying process to be used in industrial drying.
Date: August 22, 1994
Creator: Curry, D. P.
Object Type: Report
System: The UNT Digital Library
Audit of selected aspects of the Waste Isolation Pilot Plant cost structure, Carlsbad, New Mexico (open access)

Audit of selected aspects of the Waste Isolation Pilot Plant cost structure, Carlsbad, New Mexico

The Department of Energy`s (DOE) Waste Isolation Pilot Plant (WIPP), located near Carlsbad, New Mexico, is a research and development facility intended to demonstrate that transuranic waste from the Government`s defense activities can be safely disposed of in a deep geologic formation. The Fiscal Year 1994 budget for WIPP is about $185 million and includes funding for the operation of WIPP and for experiments being done by other DOE facilities. DOE`s current plan is for WIPP to begin receiving transuranic waste in June 1998. This audit was requested by the Assistant Secretary for Environmental Management because two recent reports, one issues by the Office of Inspector General (OIG), were critical of the staffing and cost-effectiveness of WIPP, and because of recent mission changes at WIPP. The audit team consisted of representatives from the DOE, auditors from the OIG, and technical specialists hired by the OIG to assist in the audit. The purpose of the audit was to determine whether WIPP was appropriately staffed to meet programmatic requirements in the most cost-effective manner. The Secretary of Energy expected DOE facilities to benchmark their performance against other facilities to strive for best in class status, and the Westinghouse management and operating contract …
Date: August 22, 1994
Creator: unknown
Object Type: Report
System: The UNT Digital Library
[Accelerator physics R&D] (open access)

[Accelerator physics R&D]

This report discusses the NEPTUN-A experiment that will study spin effects in violent proton-proton collisions; the Siberian snake tests at IUCF cooler ring; polarized gas jets; and polarized proton acceleration to 1 TeV at Fermilab.
Date: August 22, 1994
Creator: Krisch, A. D.
Object Type: Report
System: The UNT Digital Library
Multidimensional discretization of conservation laws for unstructured polyhedral grids (open access)

Multidimensional discretization of conservation laws for unstructured polyhedral grids

To the extent possible, a discretized system should satisfy the same conservation laws as the physical system. The author considers the conservation properties of a staggered-grid Lagrange formulation of the hydrodynamics equations (SGH) which is an extension of a ID scheme due to von Neumann and Richtmyer (VNR). The term staggered refers to spatial centering in which position, velocity, and kinetic energy are centered at nodes, while density, pressure, and internal energy are at cell centers. Traditional SGH formulations consider mass, volume, and momentum conservation, but tend to ignore conservation of total energy, conservation of angular momentum, and requirements for thermodynamic reversibility. The author shows that, once the mass and momentum discretizations have been specified, discretization for other quantities are dictated by the conservation laws and cannot be independently defined. The spatial discretization method employs a finite volume procedure that replaces differential operators with surface integrals. The method is appropriate for multidimensional formulations (1D, 2D, 3D) on unstructured grids formed from polygonal (2D) or polyhedral (3D) cells. Conservation equations can then be expressed in conservation form in which conserved currents are exchanged between control volumes. In addition to the surface integrals, the conservation equations include source terms derived from physical …
Date: August 22, 1994
Creator: Burton, D.E.
Object Type: Article
System: The UNT Digital Library