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Search Publications by: Joel Ullom (Fed)

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Displaying 1 - 25 of 179

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

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

Dynamic acoustic optimization of pulse tube refrigerators for rapid cooldown

April 23, 2024
Author(s)
Ryan Snodgrass, Vincent Kotsubo, Scott Backhaus, Joel Ullom
Pulse tube refrigerators are a critical enabling technology for many disciplines that require low temperatures. These refrigerators dominate the total power consumption of most modern cryostats, including those that reach millikelvin temperatures using

Indium Bump Bonding: Advanced Integration Techniques for Low-Temperature Detectors and Readout

April 20, 2024
Author(s)
Tammy Lucas, John Biesecker, W.Bertrand (Randy) Doriese, Shannon Duff, Malcolm Durkin, Richard Lew, Joel Ullom, Michael Vissers, Dan Schmidt
We have examined the influence of bump shape and bonding pressure on low temperature electrical properties of indium bump connections including transition temperature, normal resistance, and superconducting critical current. We describe our test structures

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

Single Flux Quantum-Based Digital Control of Superconducting Qubits in a Multi-Chip Module

June 24, 2023
Author(s)
Chuanhong Liu, Robert McDermott, Britton Plourde, Andrew Ballard, Jonathan DuBois, Pete Hopkins, David Olaya, John Biesecker, Samuel P. Benz, Dan Schmidt, Joel Ullom
The single flux quantum (SFQ) digital superconducting logic family has been proposed as a practical approach for controlling next-generation superconducting qubit arrays with more favorable scaling properties compared to conventional microwave-based

Systematic Improvements in Transmon Qubit Coherence enabled by Niobium Surface Encapsulation

June 14, 2023
Author(s)
Mustafa BAL, Akshay Murthy, Francesco Crisa, Shaojiang Zhu, Florent Lecocq, Joe Aumentado, Joel Ullom, Pete Hopkins
We present a novel transmon qubit fabrication technique that yields systematic improvements in T1 coherence times. In this study, the devices are fabricated using a novel encapsulation strategy that involves passivating the surface of niobium and thereby

Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon

April 27, 2023
Author(s)
Douglas Bennett, W.Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Johnathon Gard, Gene C. Hilton, Kelsey Morgan, Galen O'Neil, Carl D. Reintsema, Dan Schmidt, Daniel Swetz, Joel Ullom, Takuma Okumura
To test the bound-state quantum electrodynamics (BSQED), we have performed high precision x- ray spectroscopy of the 5g→4f and 5f→4d transitions (BSQED contribution of 2.4 eV and 5.2 eV, respectively) of muonic neons in the low-pressure gas phase under the

A Tabletop X-Ray Tomography Instrument for Nanometer-Scale Imaging: Reconstructions

April 14, 2023
Author(s)
Zachary H. Levine, Bradley Alpert, Amber Dagel, Joseph Fowler, Edward Jiminez, Nathan J. Nakamura, Daniel Swetz, Paul Szypryt, Kyle Thompson, Joel Ullom
We show three-dimensional reconstructions of a region of an integrated circuit from a 130 nm copper process. The reconstructions employ x-ray computed tomography, measured with a new and innovative high-magnification x-ray microscope. The instrument uses a

Symmetric time-division-multiplexed SQUID readout with two-layer switches for future TES observatories

April 4, 2023
Author(s)
Malcolm Durkin, Scott Backhaus, Simon Bandler, James Chervenak, Ed Denison, W.Bertrand (Randy) Doriese, Johnathon Gard, Gene C. Hilton, Richard Lew, Tammy Lucas, Carl D. Reintsema, Dan Schmidt, Stephen Smith, Joel Ullom, Leila R. Vale, Michael Vissers, Nicholas Wakeham
Time-division multiplexing (TDM) of transition-edge-sensor (TES) microcalorimeters is being developed as the readout tech-nology for the Athena X-ray integral field unit (X-IFU) and is under consideration for future TES-bolometer missions like CMB-S4. We

Role of Non-Temperature-Gradient Power Flow Terms in Low-Temperature Regenerators

December 1, 2022
Author(s)
Ryan Snodgrass, Joel Ullom, Scott Backhaus
The total power flow through cryocooler regenerators is key to their performance because it reduces the cooling available at the cold heat exchanger. At temperatures near 4 K, the real-fluid properties of helium and the finite-heat-capacity of regenerator

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