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Search Publications by: Joel Ullom (Fed)

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Displaying 201 - 225 of 350

Operation of gamma-ray microcalorimeters at elevated count rates using filters with constraints

May 15, 2013
Author(s)
Bradley K. Alpert, Robert D. Horansky, Douglas A. Bennett, William B. Doriese, Joseph W. Fowler, Andrew Hoover, Michael W. Rabin, Joel N. Ullom
We introduce a filter construction method for pulse processing that differs in two respects from that in standard optimal filtering, in which the average pulse shape and noise power spectral density are combined to create a convolution filter for

Table-top ultrafast x-ray microcalorimeter spectrometry for molecular structure

March 26, 2013
Author(s)
Jens (. Uhlig, William B. Doriese, Joseph W. Fowler, Daniel S. Swetz, Carl D. Reintsema, Douglas A. Bennett, Leila R. Vale, Gene C. Hilton, Kent D. Irwin, Joel N. Ullom, Ilari Maasilta, Wilfred Fullagar, Niklas Gador, Sophie Canton, Kimmo Kinnunen, Villy Sundstrom
This work presents an x-ray absorption measurement by use of ionizing radiation generated by a femtosecond pulsed laser source. The spectrometer was a microcalorimetric array whose pixels are capable of accurately measuring energies of individual radiation

Macroscale refrigeration by nanoscale electron transport

February 26, 2013
Author(s)
Peter J. Lowell, Galen C. O'Neil, Jason M. Underwood, Joel N. Ullom
Nano- and Micro- Electromechanical devices (NEMS & MEMS) have become ubiquitous; examples include automobile accelerometers, inkjet printer heads, infrared viewers, and mirrors for image manipulation and projection. Applications fall broadly in the

Current Distribution and Transition Width in Superconducting Transition-Edge Sensors

December 13, 2012
Author(s)
Daniel S. Swetz, Douglas A. Bennett, Daniel R. Schmidt, Joel N. Ullom
Present models of the superconducting-to-normal transition in transition-edge sensors (TESs)do not describe the current distribution within a biased TES. This distribution is complicated by normal-metal features that are integral to TES design. We present

Observation of bias-specific telegraph noise in large transition-edge sensors

December 11, 2012
Author(s)
Vincent Y. Kotsubo, Douglas A. Bennett, Mark Croce, Michael W. Rabin, Daniel R. Schmidt, Joel N. Ullom
We have observed anomalous random telegraph noise in discrete regions of voltage bias throughout the superconducting transition in larger transition-edge sensors (TESs). The bimodal nature of these noise features is consistent with thermally activated

A high resolution gamma-ray spectrometer based on superconducting microcalorimeters

September 28, 2012
Author(s)
Douglas A. Bennett, Robert D. Horansky, Daniel R. Schmidt, Andrew Hoover, Ryan Winkler, Bradley K. Alpert, James A. Beall, William B. Doriese, Joseph W. Fowler, Gene C. Hilton, Kent D. Irwin, Nathan J. Hoteling, Vincent Y. Kotsubo, John A. Mates, Galen C. O'Neil, Michael W. Rabin, Carl D. Reintsema, Francis J. Schima, Daniel S. Swetz, Leila R. Vale, Joel N. Ullom
Improvements in superconductor device fabrication, detector hybridization techniques, and superconducting quantum interference device readout have made square-centimeter-sized arrays of gammaray microcalorimeters, based on transition-edge sensors (TESs)

A two-fluid model for the transition shape in transition-edge sensors

May 1, 2012
Author(s)
Douglas A. Bennett, Daniel S. Swetz, Robert D. Horansky, Daniel R. Schmidt, Joel N. Ullom
Superconducting microcalorimeters based on transition-edge sensors (TESs) are being successfully used in applications ranging from optical photon counting to gamma-ray and alpha particle spectroscopy. Practical instruments often require a complex

Demonstration of code-division multiplexing for x-ray microcalorimeters

February 13, 2012
Author(s)
Greg Stiehl, W.Bertrand (Randy) Doriese, Gene C. Hilton, Kent D. Irwin, Carl D. Reintsema, Dan Schmidt, Daniel Swetz, Joel Ullom, Leila R. Vale, Joseph Fowler
We demonstrate the code-division multiplexing (CDM) readout of eight transition-edge sensor microcalorimeters. The energy resolution is 3.0 eV (full width at half-maximum) or better at 5.9 keV, with a best resolution of 2.3 eV and a mean of 2.6 eV over the

Advanced Code-Division Multiplexers for Superconducting Detector Arrays

February 11, 2012
Author(s)
Kent D. Irwin, Hsiao-Mei Cho, William B. Doriese, Joseph W. Fowler, Gene C. Hilton, Michael D. Niemack, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale
Multiplexers based on the modulation of superconducting quantum interference devices are now regularly used in multi-kilopixel arrays of superconducting detectors for astrophysics, cosmology, and materials analysis. Over the next decade, much larger arrays

Optimization of the TES-bias circuit for a multiplexed microcalorimeter array

January 27, 2012
Author(s)
William B. Doriese, Bradley K. Alpert, Joseph W. Fowler, Gene C. Hilton, Alex S. Hojem, Kent D. Irwin, Carl D. Reintsema, Daniel R. Schmidt, Greg Stiehl, Daniel S. Swetz, Joel N. Ullom, Leila R. Vale
In the detector-bias circuit of a transition-edge-sensor (TES) microcalorimeter, the TES-shunt resistor (Rsh) and the thermal conductance to the cryogenic bath (G) are often considered to be interchangeable knobs with which to control detector speed