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Status And Prospects of the BaBar SVT

Description: The BABAR Silicon Vertex Tracker (SVT) has been efficiently operated for five years since the start of data taking in 1999. It has met design requirements and no degradation in its performance has been observed thus far. However, because of higher than expected background levels, and anticipated further increases in luminosity and dose rates, we have done a thorough study to assess the viability of operating the SVT until the end of the decade.
Date: May 16, 2006
Creator: Re, V.; Bruinsma, M.; Curry, S.; Kirkby, D.; Berryhill, J.; Burke, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Squeezing dip moveout for depth-variable velocity

Description: In dip moveout (DMO) processing, velocity variations with depth can be handled approximately by squeezing a constant-velocity DMO operator to narrow its impulse response. This squeezed DMO approximation provides a computationally efficient and reasonably accurate method of DMO correction for depth-variable velocity. DMO is squeezed by two modifications to constant-velocity DMO. One modification is a squeezing function of time that depends only on simple time averages of velocity that are likely… more
Date: December 1991
Creator: Hale, D. & Artley, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Stable explicit depth extrapolation of seismic wavefields

Description: Stable explicit filters for depth extrapolation of seismic wavefields may be derived through a modification of the conventional Taylor series method. The modified Taylor series method described here yields extrapolators with maximally-flat amplitude spectra in their passband, while ensuring that no spectral components in the wavefield are amplified by any factor greater than one. The price for stability is increased phase error. For low normalized frequencies, implicit extrapolators are more ac… more
Date: January 1, 1990
Creator: Hale, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

3-D Depth Migration via McClellan Transformations

Description: Three-dimensional seismic wavefields may be extrapolated in depth, one frequency at a time, by two-dimensional convolution with a circularly symmetric, frequency- and velocity-dependent filter. This depth extrapolation, performed for each frequency independently, lies at the heart of 3-D finite-difference depth migration. The computational efficiency of 3-D depth migration depends directly on the efficiency of this depth extrapolation. McClellan transformations provide an efficient method for b… more
Date: 1990~
Creator: Hale, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Squeezing dip moveout for depth-variable velocity

Description: In dip moveout (DMO) processing, velocity variations with depth can be handled approximately by squeezing a constant-velocity DMO operator to narrow its impulse response. This squeezed DMO approximation provides a computationally efficient and reasonably accurate method of DMO correction for depth-variable velocity. DMO is squeezed by two modifications to constant-velocity DMO. One modification is a squeezing function of time that depends only on simple time averages of velocity that are likely… more
Date: December 1991
Creator: Hale, D. & Artley, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Migration by the Kirchhoff, slant stack, and Gaussian beam methods

Description: Gaussian beam migration offers features that are unmatched by any other single depth migration method. Unfortunately, computer algorithms for Gaussian beam migration are more complicated and difficult to understand that those for most other methods. One way to simplify Gaussian beam migration is to understand how it is related to other methods that may be more familiar. In particular, Gaussian beam migration is similar to Kirchhoff integral migration. It is also similar to the phase-shift (or s… more
Date: August 1992
Creator: Hale, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computational aspects of Gaussian beam migration

Description: The computational efficiency of Gaussian beam migration depends on the solution of two problems: (1) computation of complex-valued beam times and amplitudes in Cartesian (x,z) coordinates, and (2) limiting computations to only those (x,z) coordinates within a region where beam amplitudes are significant. The first problem can be reduced to a particular instance of a class of closest-point problems in computational geometry, for which efficient solutions, such as the Delaunay triangulation, are … more
Date: August 1992
Creator: Hale, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computational methods for improving the resolution of subsurface seismic images. Progress report, September 15, 1991--September 14, 1993

Description: Our interactive modeling for Gaussian beam modeling in two-dimensional, triangulated complex geologic structure, has been generalized to include transmission losses at interfaces, and density and Q-characterization of attenuation in layers. Also, multiple reflections and the option to model data from VSP acquisition geometry have been included. Shortcomings when the structure contains first-order discontinuities, however, limit the full geologic complexity that presently can be modeled by the G… more
Date: May 1993
Creator: Larner, K.; Hale, D.; Bleistein, N. & Cohen, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Computational aspects of Gaussian beam migration

Description: The computational efficiency of Gaussian beam migration depends on the solution of two problems: (1) computation of complex-valued beam times and amplitudes in Cartesian (x,z) coordinates, and (2) limiting computations to only those (x,z) coordinates within a region where beam amplitudes are significant. The first problem can be reduced to a particular instance of a class of closest-point problems in computational geometry, for which efficient solutions, such as the Delaunay triangulation, are … more
Date: 1992~
Creator: Hale, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Lessons Learned From BaBar Silicon Vertex Tracker, Limits, And Future Perspectives of the Detector

Description: The silicon vertex tracker (SVT) of the BaBar experiment at PEP-II is described. This is the crucial device for the measurement of the meson decay vertices to extract charge-conjugation parity (CP) asymmetries. It consists of five layers of double-sided ac-coupled silicon strip detectors, read out by a full-custom integrated circuit, capable of simultaneous acquisition, digitization, and transmission of data. It represents the core of the BaBar tracking system, providing position measurements w… more
Date: February 17, 2006
Creator: Re, V.; Kirkby, D.; Bruinsma, M.; Curry, S.; Berryhill, J.; Burke, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

BaBar Silicon Vertex Tracker: Status and Prospects

Description: The BABAR Silicon Vertex Tracker (SVT) has been efficiently operated for six years since the start of data taking in 1999. Due to higher than expected background levels some unforeseen effects have appeared. We discuss: a shift in the pedestal for the channels of the AToM readout chips that are most exposed to radiation; an anomalous increase in the bias leakage current for the modules in the outer layers. Estimates of future radiation doses and occupancies are shown together with the extrapola… more
Date: April 27, 2006
Creator: Re, V.; Bondioli, M.; Bruinsma, M.; Curry, S.; Kirkby, D.; Berryhill, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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