Browsing by Author "Eckart, Megan E."
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Item Extended Line Spread Function of TES Microcalorimeters With Au/Bi Absorbers(IEEE, 2019-03-06) Eckart, Megan E.; Adams, Joseph S.; Bandler, Simon R.; Beaumont, Sophie; Chervenak, James A.; Datesman, Aaron M.; Finkbeiner, Fred M.; Hummatov, Ruslan; Kelley, Richard L.; Kilbourne, Caroline A.; Leutenegger, Maurice A.; Miniussi, Antoine R.; Moseley, Samuel J.; Porter, F. Scott; Sadleir, John E.; Sakai, Kazuhiro; Smith, Stephen J.; Wakeham, Nicholas; Wassell, Edward J.Microcalorimeters have the potential to provide line shapes well described by a single Gaussian broadening term of few-eV width. This attribute makes the detectors especially well suited for x-ray astrophysics observations; however, low-level non-Gaussian broadening terms are expected and must be characterized. These terms depend on the composition of the x-ray absorber, the detailed x-ray absorption physics, the device thermalization processes, and the incident x-ray energy. Here we present the first measurements targeted at understanding the extended line-spread function (LSF) of x-ray microcalorimeter pixels under development for the X-ray Integral Field Unit on the Athena X-ray Observatory. These pixels are composed of Mo/Au transition-edge sensors with overhanging electroplated Au/Bi absorbers. We have measured the line shapes using monochromatic x-ray sources with <1-eV width at several x-ray energies (0.85, 0.93, 1.25, 1.5, 5.4, and 8.0 keV) across the instrument bandpass (0.3–12 keV) and have modeled the line profiles. These results are compared to the extended LSF of the Hitomi microcalorimeter pixels that used HgTe absorbers.Item Fabrication of a Hybrid Transition Edge Sensor Array for LynxWassell, Edward; Adams, Joseph S.; Bandler, Simon R.; Chang, Meng-Ping; Chervenak, James A.; Datesman, Aaron M.; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Yoon Ha, Jong; Kelley, R.; Kilbourne, Caroline A.; Miniussi, Antoine R.; Porter, F.; Sadleir, John E.; Sakai, Kazuhiro; Smith, Stephen J.; Wakehan, NicholasItem Multiabsorber transition-edge sensors for x-ray astronomy(SPIE, 2019-04-08) Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron M.; Eckart, Megan E.; Finkbeiner, Fred M.; Hummatov, Ruslan; Kelley, Richard L.; Kilbourne, Caroline A.; Miniussi, Antoine; Porter, Frederick S.; Sadleir, John E.; Sakai, Kazuhiro; Wakeham, Nicholas; Wassell, Edward J.We are developing arrays of position-sensitive microcalorimeters for future x-ray astronomy appli cations. These position-sensitive devices commonly referred to as hydras consist of multiple x-ray absorbers, each with a different thermal coupling to a single-transition-edge sensor microcalorimeter. Their development is motivated by a desire to achieve very large pixel arrays with some modest compromise in performance. We report on the design, optimization, and first results from devices with small pitch pixels (<75 μm) being developed for a high-angular and energy resolution imaging spectrometer for Lynx. The Lynx x-ray space telescope is a flagship mission concept under study for the National Academy of Science 2020 decadal survey. Broadband full-width-half-maximum (FWHM) resolution measurements on a 9-pixel hydra have demonstrated ΔEFWHM ¼ 2.23 0.14 eV at Al-Kα, ΔEFWHM ¼ 2.44 0.29 eV at Mn-Kα, and ΔEFWHM ¼ 3.39 0.23 eV at Cu-Kα. Position discrimination is demonstrated to energies below <1 keV and the device performance is well-described by a finite-element model. Results from a prototype 20-pixel hydra with absorbers on a 50-μm pitch have shown ΔEFWHM ¼ 3.38 0.20 eV at Cr-Kα1. We are now optimizing designs specifically for Lynx and extending the number of absorbers up to 25/hydra. Numerical simulation suggests optimized designs could achieve ∼3 eV while being compatible with the bandwidth requirements of the state-of-the art multiplexed readout schemes, thus making a 100,000 pixel microcalorimeter instrument a realistic goal.