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Search Publications by: Nathan Ortiz (Fed)

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Displaying 1 - 8 of 8

Using a 4-Megapixel Hybrid Photon Counting Detector for Fast, Laboratory-Based Nanoscale X-Ray Tomography

May 12, 2026
Author(s)
Jordan Fonseca, Zachary Levine, Andras Vladar, Daniel Swetz, Felix Kim, John Henry Scott, Joseph Fowler, Nathan Ortiz, Paul Szypryt, Nathan Nakamura
Abstract Hybrid photon counting detectors (HPCDs) have unlocked new capabilities for X-ray-based measurements at synchrotrons around the world in the last 30 years. By leveraging independently optimized sensor and readout layers, they offer high quantum

Addressing Individual Persistent Current Switches With a Cryogenic Optical Scanner

March 6, 2026
Author(s)
Avirup Roy, Jonathan Dean, Galen O'Neil, Nathan Ortiz, Paul Szypryt
We demonstrate a robust and minimalist implementation of individually addressable optically actuated persistent current switches. We use a focused laser beam directed by a cryogenic laser scanner to drive a selected segment of a superconducting loop normal

Characterization of Silicon-Membrane TES Microcalorimeters for Large-Format X-ray Spectrometers with Integrated Microwave SQUID Readout

January 16, 2026
Author(s)
Avirup Roy, Robinjeet Singh, Joel Weber, William Doriese, Johnathon Gard, Mark Keller, John Mates, Kelsey Morgan, Galen O'Neil, Nathan Ortiz, Daniel Swetz, Daniel Schmidt, Joel Ullom, Evan Jahrman, Thomas Allison, Sasawat Jamnuch, John Vinson, Charles Titus, Cherno Jaye, Daniel Fischer
We present the electrothermal characterization of transition-edge sensor (TES) detectors suspended on Si membranes fabricated using a silicon-on-insulator wafer. The use of an all-silicon fabrication platform, in contrast to the more commonly used silicon

Effects of Stray Magnetic Field on Transition-edge Sensors in Gamma-ray Microcalorimeters

May 19, 2024
Author(s)
Mark Keller, Abigail Wessels, Dan Becker, Douglas Bennett, Matthew Carpenter, Mark Croce, Jozsef Imrek, Johnathon Gard, John Mates, Kelsey Morgan, Nathan Ortiz, Dan Schmidt, Katherine Schreiber, Daniel Swetz, Joel Ullom
Superconducting transition-edge sensors (TESs) used in x-ray and γ-ray microcalorimeters suffer degraded performance if cooled in a magnetic field B sufficient to trap flux in the sensors. We report measurements of γ-ray TESs before and after implementing

A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray

August 1, 2023
Author(s)
Paul Szypryt, Nathan J. Nakamura, Dan Becker, Douglas Bennett, Amber L. Dagel, W.Bertrand (Randy) Doriese, Joseph Fowler, Johnathon Gard, J. Zachariah Harris, Gene C. Hilton, Jozsef Imrek, Edward S. Jimenez, Kurt W. Larson, Zachary H. Levine, John Mates, Daniel McArthur, Luis Miaja Avila, Kelsey Morgan, Galen O'Neil, Nathan Ortiz, Christine G. Pappas, Dan Schmidt, Kyle R. Thompson, Joel Ullom, Leila R. Vale, Michael Vissers, Christopher Walker, Joel Weber, Abigail Wessels, Jason W. Wheeler, Daniel Swetz
We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines a high spatial resolution scanning electron microscope (SEM) with a highly efficient and

Design of a 3000 pixel transition-edge sensor x-ray spectrometer for microcircuit tomography

August 1, 2021
Author(s)
Paul Szypryt, Douglas Bennett, William J. Boone, Amber L. Dagel, G Dalton, William Doriese, Malcolm Durkin, Joseph Fowler, Edward Garboczi, Jonathon D. Gard, Gene Hilton, Jozsef Imrek, E S. Jimenez, Vincent Y. Kotsubo, K Larson, Zachary H. Levine, John Mates, D McArthur, Kelsey Morgan, Nathan J. Nakamura, Galen O'Neil, Nathan Ortiz, Christine G. Pappas, Carl Reintsema, Dan Schmidt, Daniel Swetz, K R. Thompson, Joel Ullom, C Walker, Joel C. Weber, Abigail Wessels, J W. Wheeler
Feature sizes in integrated circuits have decreased substantially over time, and it has become increasingly difficult to three-dimensionally image these complex circuits after fabrication. This can be important for process development, defect analysis, and

Improved plutonium and americium photon branching ratios from microcalorimeter gamma spectroscopy

October 11, 2020
Author(s)
M. D. Yoho, K. E. Koehler, Dan Becker, Douglas Bennett, M. H. Carpenter, M. P. Croce, J. D. Gard, John Mates, D. J. Mercer, Nathan Ortiz, Dan Schmidt, C. M. Smith, Daniel Swetz, A. D. Tollefson, Joel Ullom, Leila R. Vale, Abigail Wessels, D. T. Vo
Photon branching ratios are critical input data for activities such as nuclear materials protection and accounting because they allow material compositions to be extracted from measurements of gamma-ray intensities. Uncertainties in these branching ratios

A Predictive Control Algorithm for Time-Division-Multiplexed Readout of TES Microcalorimeters

January 28, 2020
Author(s)
Malcolm S. Durkin, Galen C. O'Neil, William B. Doriese, Johnathon D. Gard, Gene C. Hilton, Jozsef Imrek, Nathan J. Ortiz, Carl D. Reintsema, Robert W. Stevens, Daniel S. Swetz, Joel N. Ullom
Time division multiplexing (TDM) uses a digital flux-locked loop (DFLL) to linearize each first-stage SQUID amplifier. Presently, the dynamic range of our TDM systems is limited by the use of a proportional-integral controller to maintain the DFLL. In this
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