• Computed tomography imaging system design for shape threat detection

      Masoudi, Ahmad; Thamvichai, Ratchaneekorn; Neifeld, Mark A.; Univ Arizona, Elect & Comp Engn Dept; Univ Arizona, Coll Opt Sci; University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United States; University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United States; University of Arizona, Electrical and Computer Engineering Department, 1230 East Speedway Boulevard, Tucson, Arizona 85719, United StatesbUniversity of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States (SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2016-12-08)
      In the first part of this work, we present two methods for improving the shape-threat detection performance of x-ray computed tomography. Our work uses a fixed-gantry system employing 25 x-ray sources. We first utilize Kullback-Leibler divergence and Mahalanobis distance to determine the optimal single-source single-exposure measurement. The second method employs gradient search on Bhattacharyya bound on error rate (P-e) to determine an optimal multiplexed measurement that simultaneously utilizes all available sources in a single exposure. With limited total resources of 10(6) photons, the multiplexed measurement provides a 41.8x reduction in P-e relative to the single-source measurement. In the second part, we consider multiple exposures and develop an adaptive measurement strategy for x-ray threat detection. Using the adaptive strategy, we design the next measurement based on information retrieved from previous measurements. We determine both optimal "next measurement" and stopping criterion to insure a target P-e using sequential hypothesis testing framework. With adaptive single-source measurements, we can reduce P-e by a factor of 40x relative to the measurements employing all sources in sequence. We also observe that there is a trade-off between measurement SNR and number of detectors when we study the performance of systems with reduced detector numbers. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
    • Lynx X-Ray Observatory: an overview

      Gaskin, Jessica A; Swartz, Douglas A; Vikhlinin, Alexey; Ozel, Feryal; Gelmis, Karen E; Arenberg, Jonathan W; Bandler, Simon R; Bautz, Mark W; Civitani, Marta M; Dominguez, Alexandra; et al. (SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2019-05-29)
      Lynx, one of the four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, provides leaps in capability over previous and planned x-ray missions and provides synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx provides orders of magnitude improvement in sensitivity, on-axis subarcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources in the 0.2- to 10-keV range. The Lynx architecture enables a broad range of unique and compelling science to be carried out mainly through a General Observer Program. This program is envisioned to include detecting the very first seed black holes, revealing the high-energy drivers of galaxy formation and evolution, and characterizing the mechanisms that govern stellar evolution and stellar ecosystems. The Lynx optics and science instruments are carefully designed to optimize the science capability and, when combined, form an exciting architecture that utilizes relatively mature technologies for a cost that is compatible with the projected NASA Astrophysics budget. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.