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Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines (open access)

Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines

We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tolerance levels. Following up modeling of detector's performance, including geometrical optimization using a Gaussian beam, we fabricated and assembled a first prototype. In this paper, we describe the development of this new state-of-the-art X-ray BPM along the beamline, in particular, downstream from the monochromator.
Date: May 25, 2009
Creator: Yoon, P.S. & Siddons, D. P.
System: The UNT Digital Library
Correlation method for the measure of mask-induced line-edge roughness in extreme ultraviolet lithography (open access)

Correlation method for the measure of mask-induced line-edge roughness in extreme ultraviolet lithography

As critical dimensions for leading-edge semiconductor devices shrink, line-edge roughness (LER) requirements are pushing well into the single digit nanometer regime. At these scales many new sources of LER must be considered. In the case of extreme ultraviolet (EUV) lithography, modeling has shown the lithographic mask to be a source of significant concern. Here we present a correlation-based methodology for experimentally measuring the magnitude of mask contributors to printed LER. The method is applied to recent printing results from a 0.3 numerical aperture EUV microfield exposure tool. The measurements demonstrate that such effects are indeed present and of significant magnitude. The method is also used to explore the effects of illumination coherence and defocus and has been used to verify model-based predictions of mask-induced LER.
Date: May 25, 2009
Creator: Naulleau, Patrick
System: The UNT Digital Library
EVENT TREE ANALYSIS AT THE SAVANNAH RIVER SITE: A CASE HISTORY (open access)

EVENT TREE ANALYSIS AT THE SAVANNAH RIVER SITE: A CASE HISTORY

At the Savannah River Site (SRS), a Department of Energy (DOE) installation in west-central South Carolina there is a unique geologic stratum that exists at depth that has the potential to cause surface settlement resulting from a seismic event. In the past the particular stratum in question has been remediated via pressure grouting, however the benefits of remediation have always been debatable. Recently the SRS has attempted to frame the issue in terms of risk via an event tree or logic tree analysis. This paper describes that analysis, including the input data required.
Date: May 25, 2009
Creator: Williams, R
System: The UNT Digital Library
Collins Mechanism Contributions to Single Spin Asymmetry (open access)

Collins Mechanism Contributions to Single Spin Asymmetry

We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS process.
Date: May 25, 2009
Creator: Yuan,F.
System: The UNT Digital Library
Performance of exponential coupler in the SPS with LHC type beam for transverse broadband instability analysis (open access)

Performance of exponential coupler in the SPS with LHC type beam for transverse broadband instability analysis

We present the performance and limitations of the SPS exponential coupler [1] for transverse instability measurements with LHC type beam. Data were acquired in 2008 in the SPS in the time domain with a bandwidth of up to 2.5 GHz. The data were filtered to extract the time evolution of transverse oscillations within the less than 5 ns long LHC type bunches. We describe the data filtering techniques and show the limitations of the pick-up due to propagating modes.
Date: May 25, 2009
Creator: De Maria, R.; Fox, J. D.; Hofle, W.; Kotzian, G.; Rumolo, G.; Salvant, B. et al.
System: The UNT Digital Library