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Search Publications by: Shannon Duff (Fed)

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Displaying 1 - 17 of 17

Indium Bump Process for Low-Temperature Detectors and Readout

May 20, 2022
Author(s)
Tammy Lucas, John Biesecker, W.Bertrand (Randy) Doriese, Shannon Duff, Gene C. Hilton, Joel Ullom, Michael Vissers, Dan Schmidt
We describe our indium bump process for low-temperature detectors and associated readout. A titanium nitride under bump metallization layer (UBM) is reactively sputtered onto wiring pads as a diffusion barrier and adhesion layer. Indium is thermally

Mitigating finite bandwidth effects in time-division- multiplexed SQUID readout of TES arrays

March 11, 2021
Author(s)
Malcolm Durkin, Joseph S. Adams, Simon Bandler, James A. Chervenak, Ed Denison, W.Bertrand (Randy) Doriese, Shannon Duff, Fred M. Finkbeiner, Joseph Fowler, Johnathon Gard, Gene C. Hilton, Ruslan Hummatov, Kent Irwin, Young I. Joe, Richard L. Kelley, Caroline A. Kilbourne, Antoine R. Miniussi, Kelsey Morgan, Galen O'Neil, Christine Pappas, Frederick S. Porter, Carl D. Reintsema, Kazuhiro Sakai, Stephen J. Smith, Robert W. Stevens, Daniel Swetz, Paul Szypryt, Joel Ullom, Leila R. Vale, Nicholas A. Wakeham
Time division multiplexing (TDM) is being developed as the readout technology of the X-ray integral field unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) imaging spectrometer that is part of the European Space Agency's Athena satellite

Demonstration of 220/280 GHz Multichroic Feedhorn-Coupled TES Polarimeter

January 3, 2020
Author(s)
Samantha L. Walker, Carlos E. Sierra, Jason E. Austermann, James A. Beall, Daniel T. Becker, Bradley J. Dober, Shannon M. Duff, Gene C. Hilton, Johannes Hubmayr, Jeffrey L. Van Lanen, Jeff McMahon, Sara M. Simon, Joel N. Ullom, Michael R. Vissers
We describe the design and measurement of feedhorn-coupled, transition-edge sensor (TES) polarimeters with two passbands centered at 220 GHz and 280 GHz, intended for observations of the cosmic microwave background. Each pixel couples polarized light in

Controlling the thermal conductance of silicon nitride membranes at 100 mK temperatures with patterned metal features

August 2, 2019
Author(s)
Xiaohang Zhang, Shannon M. Duff, Gene C. Hilton, Peter J. Lowell, Kelsey M. Morgan, Daniel R. Schmidt, Joel N. Ullom
Freestanding micromachined membranes are often used for thermal isolation in electronic devices such as photon sensors. The degree of thermal isolation plays an important role in determining device performance, and so the ability to suppress the thermal

Demonstration of Athena X-IFU Compatible 40-Row Time-Division-Multiplexed Readout

March 19, 2019
Author(s)
Malcolm S. Durkin, Joseph S. Adams, Simon R. Bandler, James A. Chervenak, Saptarshi Chaudhuri, Carl S. Dawson, Edward V. Denison, William B. Doriese, Shannon M. Duff, F. M. Finkbeiner, C. T. FitzGerald, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kent D. Irwin, Young I. Joe, R. L. Kelley, Caroline A. Kilbourne, A. R. Miniussi, Kelsey M. Morgan, Galen C. O'Neil, Christine G. Pappas, F. S. Porter, Carl D. Reintsema, David A. Rudman, Kazuhiro Sakai, Stephen J. Smith, Robert W. Stevens, Daniel S. Swetz, Paul Szypryt, Joel N. Ullom, Leila R. Vale, N. Wakeham, Joel C. Weber, B. A. Young
Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3168-pixel X-ray transition-edge sensor (TES) array that will provide imaging spectroscopy for european space agency's Athena satellite mission

Optimization of Time-and Code-Division-Multiplexed Readout for Athena X-IFU

March 18, 2019
Author(s)
William B. Doriese, Simon R. Bandler, Saptarshi Chaudhuri, Carl S. Dawson, Edward V. Denison, Shannon M. Duff, Malcolm S. Durkin, C. T. FitzGerald, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kent D. Irwin, Young I. Joe, Kelsey M. Morgan, Galen C. O'Neil, Christine G. Pappas, Carl D. Reintsema, David A. Rudman, Stephen J. Smith, Robert W. Stevens, Daniel S. Swetz, Paul Szypryt, Joel N. Ullom, Leila R. Vale, Joel C. Weber, B. A. Young
Readout of a large, spacecraft-based array of superconducting transition-edge sensors (TESs) requires careful management of the layout area and power dissipation of the cryogenic-circuit components. We present three optimizations of our time- (TDM) and

Tile-and-trim micro-resonator array fabrication optimized for high multiplexing factors

November 8, 2018
Author(s)
Christopher M. McKenney, Jason E. Austermann, James A. Beall, Bradley J. Dober, Shannon M. Duff, Jiansong Gao, Gene C. Hilton, Johannes Hubmayr, Dale Li, Joel N. Ullom, Jeffrey L. Van Lanen, Michael R. Vissers
We present a superconducting micro-resonator array fabrication method that is scalable and reconfigurable and has been optimized for high multiplexing factors. The method uses uniformly sized tiles patterned on stepper photolithography reticles as the

Low-Temperature Detectors for CMB Imaging Arrays

August 3, 2018
Author(s)
Johannes Hubmayr, Jason E. Austermann, James A. Beall, Daniel T. Becker, Bradley J. Dober, Shannon M. Duff, Jiansong Gao, Gene C. Hilton, Christopher M. McKenney, Joel N. Ullom, Jeffrey L. Van Lanen, Michael R. Vissers
We review advances in low-temperature detector (LTD) arrays for cosmic microwave background (CMB) polarization experiments, with a particular emphasis on imaging arrays. We briefly motivate the science case, which has spurred a large number of independent

Microwave SQUID Multiplexer for Cosmic Microwave Background Imagers

October 11, 2017
Author(s)
Bradley J. Dober, Daniel T. Becker, Douglas A. Bennett, Sean A. Bryan, Shannon M. Duff, Johnathon D. Gard, James P. Hays-Wehle, Johannes Hubmayr, John A. Mates, Carl D. Reintsema, Leila R. Vale
Key performance characteristics are demonstrated for the microwave SQUID multiplexer (µmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we

Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER

July 7, 2016
Author(s)
Johannes Hubmayr, Jason E. Austermann, James A. Beall, Daniel T. Becker, Shannon M. Duff, Arpi L. Grigorian, Gene C. Hilton, Joel N. Ullom, Michael R. Vissers
We describe 280 GHz bolometric detector arrays that instrument the balloon-borne polarimeter spider. A primary science goal of spider is to measure large-scale B-mode polarization of the cosmic microwave back-ground (cmb) in search of the cosmic-inflation

Hotspot Relaxation Dynamics in a Current Carrying Superconductor

March 17, 2016
Author(s)
Francesco Marsili, Martin Stevens, Alex Kozorezov, Varun Verma, Colin Lambert, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Matthew Shaw, Richard Mirin, Sae Woo Nam
When a photon is absorbed in a superconductor it creates a region of nonequilibrium superconductivity referred to as a hotspot [1]. The operation of most superconducting single photon detectors (microwave kinetic inductance detectors, MKIDs [2,3]

Polarity-Controlled GaN/AlN Nucleation Layers for Selective-Area Growth of GaN Nanowire Arrays on Si(111) Substrates by Molecular Beam Epitaxy

December 18, 2015
Author(s)
Matthew D. Brubaker, Shannon M. Duff, Todd E. Harvey, Paul T. Blanchard, Alexana Roshko, Aric W. Sanders, Norman A. Sanford, Kristine A. Bertness
We have demonstrated dramatic improvement in the quality of selective-area GaN nanowire growth by controlling the polarity of the underlying nucleation layers. In particular, we find that N- polarity is beneficial for the growth of large ordered nanowire

Quasiparticle recombination in hotspots in superconducting current-carrying nanowires

August 6, 2015
Author(s)
Alex Kozorezov, Colin Lambert, Francesco Marsili, Martin Stevens, Varun Verma, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Adriana Lita, Matthew D. Shaw, Richard Mirin, Sae Woo Nam
We describe a kinetic model of recombination of nonequilibrium quasiparticles generated by single photon absorption in superconducting current-carrying nanowires. The model is developed to interpret two-photon detection experiments in which a single photon

Advanced ACTPol Multichroic Polarimeter Array Fabrication Process for 150 mm Wafers

July 22, 2015
Author(s)
Shannon M. Duff, Gene C. Hilton, Johannes Hubmayr, James A. Beall, Jason E. Austermann, Daniel T. Becker, Jeffrey L. Van Lanen
Advanced ACTPol is a third generation cosmic microwave background (CMB) receiver, deploying in 2016 on the Atacama Cosmology Telescope (ACT) in the Atacama desert of Chile. Spanning five frequency bands from 25 – 280 GHz and having a total of nearly 5800

Selective Area Growth of Ga- and N-polar GaN Nanowire Arrays on Non-Polar Si (111) Substrates

September 7, 2014
Author(s)
Matthew D. Brubaker, Shannon M. Duff, Todd E. Harvey, Paul T. Blanchard, Alexana Roshko, Aric W. Sanders, Norman A. Sanford
This study presents a technique for obtaining Ga- and N-polar Gallium Nitride nanowire (GaN NW) arrays on non-polar Si (111) substrates by use of polarity-controlled AlN/GaN buffer layers. AlN films are demonstrated to adopt Al-/N-polarity for N-/Al-rich

In situ temperature measurements for selective epitaxy of GaN nanowires

February 17, 2014
Author(s)
Kristine A. Bertness, Matthew D. Brubaker, Todd E. Harvey, Shannon M. Duff, Aric W. Sanders, Norman A. Sanford
We demonstrate with spatially resolved, in situ temperature measurements and ex situ reflectance measurements that differences in appearance for masked and unmasked surfaces on patterned growth substrates arise from wavelength-dependent emissivity

Gallium Nitride Nanowires for On-Chip Optical Interconnects on Ex-Situ Substrates

January 16, 2013
Author(s)
Matthew D. Brubaker, Paul T. Blanchard, John B. Schlager, Aric W. Sanders, Alexana Roshko, Shannon M. Duff, Jason Gray, Victor M. Bright, Norman A. Sanford, Kristine A. Bertness
In this letter we report on the fabrication, device characteristics, and optical coupling of a two-nanowire device comprising light-emitting diode and photoconductive GaN nanowires. Axial p-n junction GaN nanowires were grown by molecular beam epitaxy