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Search Publications by: Joel Ullom (Fed)

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Displaying 1 - 25 of 173

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

April 30, 2024
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
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
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
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
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
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
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
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
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
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
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

Performance of a Kinetic-Inductance Traveling-Wave Parametric Amplifier at 4 Kelvin: Toward an Alternative to Semiconductor Amplifiers

April 5, 2022
Maxime Malnou, Joe Aumentado, Michael Vissers, Jordan Wheeler, Johannes Hubmayr, Joel Ullom, Jiansong Gao
Most microwave readout architectures in quantum computing or sensing rely on a semiconductor amplifier at 4\,K, typically a high-electron mobility transistor (HEMT). Despite its remarkable noise performance, a conventional HEMT dissipates several

Measurements of Strong-Interaction Effects in Kaonic-Helium Isotopes at sub-eV Precision with x-ray microcalorimeters

March 18, 2022
Tadashi Hashimoto, S Aikawa, T. Akaishi, M Bazzi, Douglas Bennett, M Berger, D Bosnar, A. D. Butt, C. Curceanu, W.Bertrand (Randy) Doriese, Malcolm Durkin, Y Ezoe, Joseph Fowler, H. Fujioka, Johnathon Gard, C Guaraldo, F.P. Gustafsson, C. Han, R Hayakawa, R. S. Hayano, T Hayashi, J. Hays-Wehle, Gene C. Hilton, T Hiraiwa, M Hiromoto, Y Ichinoge, M Iio, Y Iizawa, M Iliescu, S Ishimoto, Y Ishisaki, K Itahashi, M Iwasaki, Y Ma, T Murakami, T Nishi, H Noda, K Nomura, H Noumi, K Ooi, H Outa, K Piscicchia, Carl D. Reintsema, Y Sada, S Okada, Galen O'Neil, Dan Schmidt, Daniel Swetz, Joel Ullom, S Yamada, J Uhlig
We have measured the 3 d→ 2 p transition x rays of kaonic He 3 and He 4 atoms using superconducting transition-edge-sensor microcalorimeters with an energy resolution better than 6 eV (FWHM). We determined the energies to be 6224.5±0.4 (stat)±0.2 (syst) eV

Brominated nanoscale diamond enables room temperature and catalysis free functionalization chemistry

January 27, 2022
Cynthia Melendrez, Jorge Lopez-Rosas, Tsz Cheung, Camron Stokes, Sang-Jun Lee, Jan Vavra, Helena Raabova, Vaclav Vanek, Sami Sainio, Dennis Nordlund, W.Bertrand (Randy) Doriese, Galen O'Neil, Daniel Swetz, Joel Ullom, Kent Irwin, Peter Cigler, Polo Tran, Halim Muhammad, Virginia Altoe, Charles Titus, Jocelyn Valenzuela, Grace Jeanpierre, Abraham Wolcott
Bromination of diamond surfaces has not been explored and can potentially open new avenues for increased chemical reactivity. Aerobically oxidized high-pressure high-temperature nanoscale diamond (ND) is a widely used host for the nitrogen vacancy centers

Sub-kelvin thermometer for on-chip measurements of microwave devices utilizing two-level systems in superconducting microresonators

November 13, 2021
Jordan Wheeler, Michael Vissers, Maxime Malnou, Johannes Hubmayr, Joel Ullom, Jiansong Gao
The design, implementation, and sensitivity of a new microwave multiplexable superconducting resonator thermometer based on two-level-systems are presented. The thermometer operates from 1 K to 50 mK and has the potential to measure down to 5 mK. The

Proceedings of the 2nd CREST Nano-Virtual-Labs Joint Workshop on Superconductivity

October 12, 2021
Kent D. Irwin, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, John Mates, Nathan A. Tomlin, Galen O'Neil, Carl D. Reintsema, Dan Schmidt, Joel Ullom, Leila R. Vale
Superconductivity is a powerful tool for the detection of electromagnetic radiation and the energy in particle interactions. One leading superconducting detector technology is the superconducting transition-edge sensor (TES), which uses a superconducting

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

August 1, 2021
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