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Search Publications by: Joel Ullom (Fed)

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Displaying 1 - 25 of 198

Development Toward Tungsten Transition-Edge Sensors with Improved Energy Resolution in the Optical/NIR Regime

April 22, 2026
Author(s)
Leaf Swordy, Adriana Lita, Benedikt Hampel, Daniel Swetz, Paul Szypryt, Douglas Bennett, Galen O'Neil, Michael Vissers, Joel Ullom, Richard Mirin, Martin Stevens
We formulate an energy resolution model for optical transition-edge sensors which combines aspects of existing models with the goal of better defining and constraining energy resolution optimization. The combined model is found to be in better agreement

A study of the position-dependent response of thermal kinetic inductance detectors through the use of cryogenic beam steering

April 2, 2026
Author(s)
Ian Fogarty Florang, Jonathan Dean, Joseph Fowler, Tom-Erik Haugen, Shannon Hoogerheide, Daniel Jardin, Hans Mumm, Nathan Nakamura, Matthew Natale, Galen O'Neil, Nathan Ortiz, Jeremy Paster, Thomas Rao, Avirup Roy, Daniel Swetz, Joel Ullom, Michael Vissers, Paul Szypryt
There are a number of considerations when designing a low-temperature detector for the best possible energy resolution. One that has been particularly challenging for thermal kinetic inductance detectors (TKIDs) is ensuring that the detector's response to

Prospects of kinetic inductance current sensors for multiplexed microcalorimeter readout

March 12, 2026
Author(s)
Galen O'Neil, Simon Bandler, Ian Fogarty Florang, John Mates, Daniel Swetz, Paul Szypryt, Thomas Stevenson, Leaf Swordy, Joel Ullom, Michael Vissers, Jordan Wheeler, Wonsik Yoon
Superconducting microcalorimeter arrays with hun- dreds to thousands of pixels are enabling new measurements and capabilities in exotic atom spectroscopy, x-ray astronomy, nuclear materials analysis, and many other fields. We consider the prospects of

Low-frequency cryocoolers are compressed inefficiently

March 10, 2026
Author(s)
Ryan Snodgrass, Vincent Kotsubo, Jens Hoehne, Joel Ullom
Millikelvin refrigerators are enabling tools for many fields of modern science, including quantum information processing. They are typically precooled to 4 K by low-frequency pulse-tube refrigerators, which perform a thermodynamic cycle based on

A laser scanning device for cryogenic beam steering

March 2, 2026
Author(s)
Jonathan Dean, Avirup Roy, Nathan Ortiz, Joel Weber, Joel Ullom, Daniel Swetz, Galen O'Neil
It is often desirable to steer light within a cryostat and have a well focussed laser spot incident upon a detector. We demonstrate operation of superconducting transition-edge sensor microcalorimeters with a laser scanning device co-located on the 20 mK

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

Most stringent bound on electron neutrino mass obtained with a scalable low temperature microcalorimeter array

September 29, 2025
Author(s)
Bradley Alpert, Daniel Becker, Douglas Bennett, Joseph Fowler, Johnathon Gard, John Mates, Carl Reintsema, Daniel Schmidt, Daniel Swetz, Joel Ullom, Leila Vale, M. Balata, S. Nisii, A. Bevilacqua, M. De Gerone, G. Gallucci, L. Parodi, F. Siccardi, A. Borghesi, P. Campana, R. Carobene, M. Faverzani, A. Giachero, M. Gobbo, D. Labrbca, R. Morette, A. Nuciotti, L. Origo, S. Ragazzi, G. Ceruti, E. Ferri, G. Pessina, E. Celasco, F. Gatti, R. Dressler, E. Maugeri, D. Schumann, U Koster, M. Lusignoli, P. Manfrinetti, F Ahrens, E Bogini, M. Borghesi, P. Campana, R. Carbene, L. Ferrari Barusso, E. Ferri, G. Gallucci
The determination of the absolute neutrino mass scale remains a fundamental open question in particle physics, with profound implications for both the standard model and cosmology. Direct kinematic measurements, independent of model-dependent assumptions,

Speciation of cesium in a radiocesium-bearing microparticle emitted from Unit 1 during the Fukushima nuclear accident by XANES spectroscopy using transition edge sensor

September 5, 2025
Author(s)
Yoshio Takahashi, Shinya Yamada, Hikaru Miura, Yuichi Kurihara, Oki Sekizawa, Kiyofumi Nitta, Tadashi Hashimoto, Masato Tanaka, Minako Kurisu, Shinji Okada, Takaaki Itai, Hiroki Suga, Teruhiko Kashiwabara, Kohei Sakata, Hideyuki Tatsuno, Ryota Hayakawa, Hirotaka Suda, Takaya Ohashi, Yoshitaka Ishisaki, Takuma Okumura, Yuto Ichinohe, Tasuku Hayashi, Yuki Imai, Hirofumi Noda, Toru Tamagawa, Tadaaki Isobe, Toshiyuki Azuma, William Doriese, Joel Ullom, Daniel Swetz, Malcolm Durkin, Galen O'Neil, Satoshi Kohjiro, Shogo Higaki, Daisuke Tsumune, Masayoshi Yamamoto, Tomoya Uruga
The chemical state of radiocesium (RCs) was determined using X-ray absorption near-edge structure (XANES) in fluorescence mode and microbeam X-ray fluorescence (μ-XRF) mapping for the cesium (Cs) incorporated in a radiocesium-bearing silica microparticle

Demonstration of a 1,820 channel microwave superconducting quantum1 interference device multiplexer for transition-edge sensor bolometers

July 15, 2025
Author(s)
John Groh, Jason Austermann, James Beall, Shannon Duff, Johannes Hubmayr, Richard Lew, Michael Link, Tammy Lucas, John Mates, Robinjeet Singh, Joel Ullom, Leila Vale, Jeffrey Van Lanen, Michael Vissers
The scalability of most transition-edge sensor arrays is limited by the multiplexing technology which combines their18 signals over a reduced number of wires and amplifiers. In this letter, we present and demonstrate a new multiplexer19 design optimized

Description of the electronic structure of oxyhemoglobin using Fe L-edge X-ray absorption spectroscopy

June 11, 2025
Author(s)
Augustin Braun, Charles Titus, Michael Baker, Max Waters, James Yan, Sang-Jun Lee, Dennis Nordlund, William Doriese, Galen O'Neil, Daniel Schmidt, Daniel Swetz, Joel Ullom, Kent Irwin, Edward Solomon
The electronic structure of oxyhemoglobin (oxyHb), the O2-bound form of the oxygen carrier, has been controversial since the discovery of its diamagnetism in 1936. This study uses partial fluorescence yield Fe L-edge X-ray absorption spectroscopy (XAS) in

280-GHz aluminum MKID arrays for the Fred Young Submillimeter Telescope

May 29, 2025
Author(s)
Anna Vaskuri, Jordan Wheeler, Jason Austermann, Michael Vissers, James Beall, James R. Burgoyne, Victoria Butler, Scott Chapman, Steve K. Choi, Abigail Crites, Cody J. Duell, Rodrigo Freundt, Anthony Huber, Zachary Huber, Johannes Hubmayr, Jozsef Imrek, Ben Keller, Lawrence Lin, Alicia Middleton, Michael D. Niemack, Thomas Nikola, Douglas Scott, Adrian Sinclair, Ema Smith, Gordon Stacey, Joel Ullom, Jeffrey Van Lanen, Eve Vavagiakis, Samantha Walker, Bugao Zou
First light observations of the 280 GHz instrument module of the Fred Young Submillimeter Telescope (FYST) in the CCAT Collaboration are expected in 2026. The focal plane of this module will consist of three superconducting microwave kinetic inductance

Application of hard x-ray and gamma-ray TES microcalorimeters at an accelerator facility

January 24, 2025
Author(s)
Takeshi Saito, Shinji Okada, Yuichi Toyoma, Toshiyuki Azuma, Goncalo Baptista, Daniel Becker, Douglas Bennett, William Doriese, Joseph Fowler, Johnathon Gard, Tadashi Hashimoto, Ryota Hayakawa, Tasuku HAYASHI, Yuto Ichinohe, Josef Imrek, Paul Indelicato, Tadaaki Isobe, Sohtaro Kanda, Naritoshi Kawamura, John Mates, Yasuhiro Miyake, Kelsey Morgan, Hirofumi Noda, Galen O'Neil, Takuma Okumura, Nancy Paul, Daniel Schmidt, Kouichiro Shimomura, Patrick Strasser, Daniel Swetz, Tadayuki Takahashi, Motonobu Tampo, Joel Ullom, Izumi Umegaki, Joel Weber, Shinya Yamada, Daikang Yan
The x-ray spectroscopy of the muonic atom has attracted atomic, nuclear, and particle physicists since its discovery. The properties of a muonic atom, such as its binding energy or atomic radius, are different from an ordinary atom because of the

Towards Precision Spectroscopy of Antiprotonic Atoms for Probing Strong-field QED

January 15, 2025
Author(s)
Goncalo Baptista, Shikha Rathi, Michael Roosa, Quentin Senetaire, Jonas Sommerfeldt, Toshiyuki Azuma, Daniel Becker, Francois Butin, Ofir Eizenberg, Joseph Fowler, Hiroyuki Fujioka, Davide Gamba, Nabil Garroum, Mauro Guerra, Tadashi Hashimoto, Takashi Higuchi, Paul Indelicato, Jorge Machado, Kelsey Morgan, Francois Nez, Jason Nobles, Ben Ohayon, Shinji Okada, Daniel Schmidt, Daniel Swetz, Joel Ullom, Pauline Yzombard, Marco Zito, Nancy Paul
PAX (antiProtonic Atom X-ray spectroscopy) is a new experiment with the aim to test strong-field quantum electrodynamics (QED) effects by performing high-precision x-ray spectroscopy of antiprotonic atoms. By utilizing advanced microcalorimeter detection

EMI susceptibility of a differential time-division SQUID multiplexing circuit for TES readout

January 3, 2025
Author(s)
Malcolm Durkin, Douglas Bennett, William Doriese, Johnathon Gard, Johannes Hubmayr, Richard Lew, Erin Maloney, Carl Reintsema, Robinjeet Singh, Daniel Schmidt, Joel Ullom, Leila Vale, Michael Vissers
Time Division multiplexing (TDM) using superconducting quantum interference devices (SQUIDs) is being developed to read out Transition-edge sensor arrays for the Athena X-ray integral field Unit (X-IFU) and Cosmic Microwave Background Stage-4, which have

Computed models of natural radiation backgrounds in qubits and superconducting detectors

December 9, 2024
Author(s)
Joseph Fowler, Ian Fogarty Florang, Nathan Nakamura, Daniel Swetz, Paul Szypryt, Joel Ullom
Naturally occurring radiation backgrounds cause correlated decoherence events in superconducting qubits. These backgrounds include gamma rays produced by terrestrial radioisotopes and cosmic rays. We use the particle-transport code Geant4 and the PARMA

Spectroscopic Measurements and Models of Energy Deposition in the Substrate of Quantum Circuits by Natural Ionizing Radiation

November 12, 2024
Author(s)
Joseph Fowler, Paul Szypryt, Raymond Bunker, Ellen Edwards, Ian Fogarty Florang, JIANSONG GAO, Shannon Hoogerheide, Ben Loer, Hans Mumm, Nathan Nakamura, John Orrell, Elizabeth M. Scott, Jason Stevens, Daniel Swetz, Brent VanDevender, Michael Vissers, Joel Ullom
Naturally occurring background radiation is a potential source of correlated decoherence events in superconducting qubits that will challenge error-correction schemes. In order to characterize the radiation environment in an unshielded laboratory

Kinetic inductance current sensor for visible to near-infrared wavelength transition-edge sensor readout

November 6, 2024
Author(s)
Paul Szypryt, Douglas Bennett, Ian Fogarty Florang, Joseph Fowler, Jiansong Gao, Andrea Giachero, Ruslan Hummatov, Adriana Lita, John Mates, Sae Woo Nam, Daniel Swetz, Joel Ullom, Michael Vissers, Jordan Wheeler
Single-photon detectors based on the superconducting transition-edge sensor are used in a number of visible to near-infrared applications, particularly for photon-number-resolving measurements in quantum information science. To be practical for large-scale

Comparison of Three Methods for Oscillating Flow Measurements in Cryocoolers

October 16, 2024
Author(s)
Ryan Snodgrass, Vincent Kotsubo, Joel Ullom
Measurement of oscillating mass flows is typically required for the study of cryocoolers and cryocooler compressors. Although many measurement techniques are used in the cryocooler literature, detailed comparisons are lacking, so it can be challenging for

Flexible superconducting wiring for integration with low temperature detector and readout fabrication

September 14, 2024
Author(s)
Galen O'Neil, Daniel Swetz, Joel Ullom, Daniel Schmidt, Joel Weber, John Mates, William Doriese, Mark Keller, Michael Vissers, Kelsey Morgan, Robinjeet Singh
We present a method of creating high density superconducting flexible wiring on flexible thin silicon substrates. The flexible wiring, called SOI flex, is created by depositing superconducting wiring on a silicon on insulator (SOI) wafer, selectively

Few-electron highly charged muonic Ar atoms verified by electronic K xrays

July 10, 2024
Author(s)
Takuma Okumura, Toshiyuki Azuma, Douglas Bennett, W. Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Johnathon Gard, Tadashi Hashimoto, Ryota Hayakawa, Yuto Ichinohe, Paul Indelicato, Tadaaki Isobe, Sohtaro Kanda, Daiji Kato, Miho Katsuragawa, Naritoshi Kawamura, Yasushi Kino, Nao Kominato, Yasuhiro Miyake, Kelsey Morgan, Hirofumi Noda, Galen O'Neil, Shinji Okada, Kenichi Okutsu, Nancy Paul, Carl D. Reintsema, Toshiki Sato, Dan Schmidt, Kouichiro Shimomura, Patrick Strasser, Daniel Swetz, Tadayuki Takahashi, Shinichiro Takeda, Soshi Takeshita, Motonobu Tampo, Hideyuki Tatsuno, Tong Xiao-Min, Joel Ullom, Shin Watanabe, Shinya Yamada, Takuma Yamashita
Electronic K x rays emitted by muonic Ar atoms in the gas phase were observed using a superconducting transition-edge-sensor microcalorimeter. The high-precision energy spectra provided a clear signature of the presence of muonic atoms accompanied by a few

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

The Simons Observatory: Production-Level Fabrication of the Mid- and Ultra-High-Frequency Wafers

May 4, 2024
Author(s)
Shannon Duff, Jason Austermann, James Beall, David Daniel, Johannes Hubmayr, Gregory Jaehnig, Bradley Johnson, Dante Jones, Michael J. Link, Tammy Lucas, Rita Sonka, Suzanne Staggs, Joel Ullom, Yuhan Wang
The Simons Observatory (SO) is a cosmic microwave background instrumentation suite in the Atacama Desert of Chile. More than 65,000 polarization-sensitive transition-edge sensor (TES) bolometers will be fielded in the frequency range spanning 27 to 280 GHz

Nanoscale Three-Dimensional Imaging of Integrated Circuits Using a Scanning Electron Microscope and Transition-Edge Sensor Spectrometer

April 30, 2024
Author(s)
Nathan Nakamura, Paul Szypryt, Amber Dagel, Bradley Alpert, Douglas Bennett, W.Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Dylan Fox, Johnathon Gard, Ryan Goodner, James Zachariah Harris, Gene C. Hilton, Edward Jimenez, Burke Kernen, Kurt Larson, Zachary H. Levine, Daniel McArthur, Kelsey Morgan, Galen O'Neil, Christine Pappas, Carl D. Reintsema, Dan Schmidt, Peter Schulz, Daniel Swetz, Kyle Thompson, Joel Ullom, Leila R. Vale, Courtenay Vaughan, Christopher Walker, Joel Weber, Jason Wheeler
X-ray nanotomography is a powerful tool for the characterization of nanoscale materials and structures, but it is difficult to implement due to the competing requirements of X-ray flux and spot size. Due to this constraint, state-of-the-art nanotomography
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