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Search Publications by: Joel Ullom (Fed)

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Displaying 26 - 50 of 350

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

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

April 5, 2022
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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
Author(s)
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