Design and construction of a radiation resistant quadrupole using metal oxide insulated CICC (open access)

Design and construction of a radiation resistant quadrupole using metal oxide insulated CICC

The construction of a engineering test model of a radiation resistant quadrupole is described. The cold-iron quadrupole uses coils fabricated from metal-oixide (synthetic spinel) insulated Cable-In-Conduit-Conductor (CICC). The superconductor is NbTi in a copper matrix. The quadrupole is designed to produce a pole-tip field of 2 T with an operating current of 7,000 A.
Date: December 28, 2012
Creator: Zeller, Albert F.
Object Type: Report
System: The UNT Digital Library
HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION (open access)

HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION

During Phase I, the following goals were achieved: (1) design and fabrication of a novel, nano-dimensional CNT field emitter assembly for high current density application, with high durability; (2) fabrication of a ceramic based micro channel plate (MCP) and characterization of its secondary electron emission; and (3) characterizing the CNT/MCP cathode for high field emission and durability. As a result of these achievements, a relatively high current density of ~ 1.2 A/cm2 from a CNT cathode and single channel MCP were measured. The emission current was also extremely stable with a peak-to-peak variation of only 1.8%. The emission current could be further enhanced to meet requirements for electron lens applications by increasing the number of MCP channels. A calculation for maximum possible current density with a 1200 channel/cm2 MCP, placed over a cathode with 1200 uniformly functioning CNTs, would be ~1.46 kA/cm2, neglecting space charge limitations. Clearly this level of emission is far greater than what is needed for the electron lens application, but it does offer a highly comforting margin to account for sub-standard emitters and/or to allow the lesser challenge of building a cathode with fewer channels/cm2. A satisfactory goal for the electron lens application would be a …
Date: December 28, 2012
Creator: Hirshfield, Jay L.
Object Type: Report
System: The UNT Digital Library
I/O Forwarding on Livermore Computing Commodity Linux Clusters (open access)

I/O Forwarding on Livermore Computing Commodity Linux Clusters

None
Date: December 28, 2012
Creator: Garlick, J E
Object Type: Report
System: The UNT Digital Library
The Radio and Optical Luminosity Evolution of Quasars II - The SDSS Sample (open access)

The Radio and Optical Luminosity Evolution of Quasars II - The SDSS Sample

We determine the radio and optical luminosity evolutions and the true distribution of the radio loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining SDSS optical and FIRST radio data. We apply the method of Efron and Petrosian to access the intrinsic distribution parameters, taking into account the truncations and correlations inherent in the data. We find that the population exhibits strong positive evolution with redshift in both wavebands, with somewhat greater radio evolution than optical. With the luminosity evolutions accounted for, we determine the density evolutions and local radio and optical luminosity functions. The intrinsic distribution of the radio loudness parameter R is found to be quite different than the observed one, and is smooth with no evidence of a bi-modality in radio loudness. The results we find are in general agreement with the previous analysis of Singal et al., 2011 which used POSS-I optical and FIRST radio data.
Date: December 28, 2012
Creator: Singal, J.; Petrosian, V.; Stawarz, L. & Lawrence, A.
Object Type: Article
System: The UNT Digital Library
Roles of Information Technology in Nuclear Criticality Safety Training (open access)

Roles of Information Technology in Nuclear Criticality Safety Training

None
Date: December 28, 2012
Creator: Huang, S.; Lee, M.; Morman, J.; Goold, R.; Lee, C. & Heinrichs, D.
Object Type: Article
System: The UNT Digital Library