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Search Publications by: Joel Ullom (Fed)

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Displaying 76 - 100 of 350

Development of a transition-edge sensor bilayer process providing new modalities for critical temperature control

September 21, 2020
Author(s)
Joel Weber, Kelsey Morgan, Daikang Yan, Christine Pappas, Abigail Wessels, Galen O'Neil, Douglas Bennett, Gene C. Hilton, Daniel Swetz, Joel Ullom, Dan Schmidt
Transition-edge sensors (TESs) are thermal detectors in which a superconducting film that is electrically biased in the superconducting-to-normal transition is used as a thermometer. In most TESs, the film is a superconductor-normal metal bilayer where the

Measurement of the 2P1/2-2P3/2 fine structure splitting in fluorine-like Kr, W, Re, Os and Ir

September 2, 2020
Author(s)
Galen O'Neil, Samuel C. Sanders, Paul Szypryt, Dipti Goyal, Amy Gall, Yang Yang, Samuel M. Brewer, W.Bertrand (Randy) Doriese, Joseph Fowler, Daniel Swetz, Joseph N. Tan, Joel Ullom, Andrey V. Volotka, Endre Takacs, Yuri Ralchenko
Quantum electrodynamics (QED) is currently considered to be one of the most accurate theories of fundamental interactions. As its extraordinary precision offers unique scientific opportunities, e.g., search for new physics, stringent experimental tests of

Compact 1.7 K Cryocooler for Superconducting Nanowire Single-Photon Detectors

June 18, 2020
Author(s)
Vincent Y. Kotsubo, Joel N. Ullom, Sae Woo Nam
State-of-the-art superconductor-based cryogenic detector systems are being installed at numerous research facilities worldwide and are achieving world-record sensitivities in a variety of applications. Implementation has been greatly facilitated by closed

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

Demonstration of 220/280 GHz Multichroic Feedhorn-Coupled TES Polarimeter

January 3, 2020
Author(s)
Samantha L. Walker, Carlos E. Sierra, Jason E. Austermann, James A. Beall, Daniel T. Becker, Bradley J. Dober, Shannon M. Duff, Gene C. Hilton, Johannes Hubmayr, Jeffrey L. Van Lanen, Jeff McMahon, Sara M. Simon, Joel N. Ullom, Michael R. Vissers
We describe the design and measurement of feedhorn-coupled, transition-edge sensor (TES) polarimeters with two passbands centered at 220 GHz and 280 GHz, intended for observations of the cosmic microwave background. Each pixel couples polarized light in

A transition-edge sensor-based x-ray spectrometer for the study of highly charged ions at the National Institute of Standards and Technology electron beam ion trap

December 16, 2019
Author(s)
Paul Szypryt, Galen C. O'Neil, Endre Takacs, Joseph N. Tan, Sean W. Buechele, Aung Naing, Douglas A. Bennett, William B. Doriese, Malcolm S. Durkin, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kelsey M. Morgan, Carl D. Reintsema, Daniel R. Schmidt, Daniel S. Swetz, Joel N. Ullom, Yuri Ralchenko
We report on the design, commissioning, and initial measurements of a Transition-Edge Sensor (TES) x-ray spectrometer for the Electron Beam Ion Trap (EBIT) at the National Institute of Standards and Technology (NIST). Over the past few decades, the NIST

On Low-Energy Tail Distortions in the Detector Response Function of X-Ray Microcalorimeter Spectrometers

November 21, 2019
Author(s)
Galen C. O'Neil, Paul Szypryt, Endre Takacs, Joseph N. Tan, Sean W. Buechele, Aung Naing, Young I. Joe, Daniel S. Swetz, Daniel R. Schmidt, William B. Doriese, Johnathon D. Gard, Carl D. Reintsema, Joel N. Ullom, John S. Villarrubia, Yuri Ralchenko
We use narrow spectral lines from the X-ray spectra of various highly charged ions to measure low-energy tail-like deviations from a Gaussian response function in a microcalorimeter X-ray spectrometer with Au absorbers at energies from 650 to 3320 eV. We

Crosstalk in microwave SQUID multiplexers

November 15, 2019
Author(s)
John A. Mates, Daniel T. Becker, Douglas A. Bennett, Bradley J. Dober, Johnathon D. Gard, Gene C. Hilton, Daniel S. Swetz, Leila R. Vale, Joel N. Ullom
Low-temperature detector technologies provide extraordinary sensitivity for applications ranging from precision measurements of the cosmic microwave background to high-resolution, high-rate x-ray, and c-ray spectroscopy. To utilize this sensitivity, new

A Robust Principal Component Analysis for Outlier Identification in Messy Microcalorimeter Data

November 12, 2019
Author(s)
Joseph W. Fowler, Bradley K. Alpert, Young I. Joe, Galen C. O'Neil, Daniel S. Swetz, Joel N. Ullom
A principal component analysis (PCA) of clean microcalorimeter pulse records can be a first step beyond statistically optimal linear filtering of pulses toward a fully nonlinear analysis. For PCA to be practical on spectrometers with hundreds of sensors

Expanding the Capability of Microwave Multiplexed Readout for Fast Signals in Microcalorimeters

November 11, 2019
Author(s)
Kelsey M. Morgan, Daniel T. Becker, Douglas A. Bennett, Johnathon D. Gard, Jozsef Imrek, John A. Mates, Christine G. Pappas, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Joel C. Weber, Abigail L. Wessels, Daniel S. Swetz
Microwave SQUID multiplexing has become a key technology for reading out large arrays of X-ray and gamma-ray microcalorimeters with mux factors of 100 or more. The desire for fast X-ray pulses that accommodate photon counting rates of hundreds or thousands

Soft X-ray spectroscopy with transition-edge sensors at Stanford Synchrotron Radiation Lightsource beamline 10-1

November 5, 2019
Author(s)
Sang-Jun Lee, Charles Titus, Roberto A. Mori, Michael Baker, Douglas Bennett, Hsiao-Mei Cho, W.Bertrand (Randy) Doriese, Joseph Fowler, Kelly J. Gaffney, Allesandro Gallo, Johnathon Gard, Gene C. Hilton, Hoyoung Jang, Young I. Joe, Christopher Kenney, Jason Knight, Thomas Kroll, Jun-Sik Lee, Dale Li, Donhui Lu, Ronald Marks, Michael Minitti, Kelsey Morgan, Ogasawara Hirohito, Galen O'Neil, Carl D. Reintsema, Dan Schmidt, Dimosthenis Sokaras, Joel Ullom, Tsu-Chien Weng, Christopher Williams, Betty A. Young, Daniel Swetz, Kent D. Irwin, Dennis Nordlund
We present results obtained with a new soft X-ray spectrometer based on transition-edge sensors (TESs) composed of Mo/Cu bilayers coupled to bismuth absorbers. This spectrometer simultaneously provides excellent energy resolution, high detection efficiency

Controlling the thermal conductance of silicon nitride membranes at 100 mK temperatures with patterned metal features

August 2, 2019
Author(s)
Xiaohang Zhang, Shannon M. Duff, Gene C. Hilton, Peter J. Lowell, Kelsey M. Morgan, Daniel R. Schmidt, Joel N. Ullom
Freestanding micromachined membranes are often used for thermal isolation in electronic devices such as photon sensors. The degree of thermal isolation plays an important role in determining device performance, and so the ability to suppress the thermal