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Search Publications by: Dan Schmidt (Fed)

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Displaying 51 - 75 of 77

Vapor Phase Metal-assisted Chemical Etching of Silicon

March 14, 2013
Author(s)
Owen J. Hildreth, Daniel R. Schmidt
This work introduces and explores Vapor Phase Metal-assisted Chemical Etching (VP-MaCE) of silicon as a method to bypass some of the challenges found in traditional Liquid Phase Metal-assisted Chemical Etching (LP-MaCE). Average etch rates for Ag, Au, and

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

Optimization and analysis of code-division multiplexed TES microcalorimeters

January 20, 2012
Author(s)
Joseph W. Fowler, William B. Doriese, Gene C. Hilton, Kent D. Irwin, Daniel R. Schmidt, Greg Stiehl, Daniel S. Swetz, Joel N. Ullom, Leila R. Vale
We are developing code-division multiplexing (CDM) readout systems for TES arrays for good scalability to large multiplexing factors. We report high energy resolution x-ray measurements made through four-channel CDM that employ a flux-summing architecture

Strongly quadrature-dependent noise in superconducting microresonators measured at the vacuum-noise limit

June 9, 2011
Author(s)
Jiansong Gao, Kent D. Irwin, Gene C. Hilton, John A. Mates, Daniel R. Schmidt, Leila R. Vale, Konrad W. Lehnert, Francois Mallet, Jonas Zmuidzinas
We report noise measurement of superconducting micro-resonators with a Josephson parametric amplifier. These resonators show significant amount of frequency noise caused by surface two-level systems. However, in the dissipation quadrature, no excess noise

Al-Mn transition edge sensors for cosmic microwave background polarimeters

November 22, 2010
Author(s)
Daniel R. Schmidt, Hsiao-Mei Cho, Johannes Hubmayr, Peter J. Lowell, Michael D. Niemack, Galen C. O'Neil, Joel N. Ullom, Ki W. Yoon, Kent D. Irwin
Superconducting transition edge sensors (TES) require superconducting films with transition temperatures (Tc)and properties that can be tailored to the particular requirements of individual applications. We have been developing Al-Mn films with a tunable

Al-Mn Transition Edge Sensors for Cosmic Microwave Background Polarimeters

November 22, 2010
Author(s)
Daniel R. Schmidt, Hsiao-Mei Cho, Johannes Hubmayr, Peter J. Lowell, Michael D. Niemack, Galen C. O'Neil, Joel N. Ullom, Ki W. Yoon, Kent D. Irwin, W L. Holzapfel, M Lueker, E M. George, E Shirokoff
Superconducting transition edge sensors (TES) require superconducting films with transition temperatures (Tc)and properties that can be tailored to the particular requirements of individual applications. We have been developing Al-Mn films with a tunable

An Analytical Model for Pulse Shape and Electrothermal Stability in Two-Body Microcalorimeters

September 9, 2010
Author(s)
Douglas A. Bennett, Robert D. Horansky, Daniel R. Schmidt, Daniel S. Swetz, Leila R. Vale, Joel N. Ullom, Andrew Hoover, Michael W. Rabin, Nathan J. Hoteling
High resolution superconducting gamma-ray sensors show potential for the more accurate analysis of nuclear material. These devices are part of a larger class of microcalorimeters and bolometers based on transition edge sensors (TESs) that have two distinct

Quasiparticle Density of States Measurements in Clean Superconducting AlMn Alloys

May 6, 2010
Author(s)
Galen C. O'Neil, Daniel R. Schmidt, Nathan A. Tomlin, Joel N. Ullom
Aluminum doped with Manganese (AlMn) forms a superconducting alloy with the transition temperature suppressed by the added Manganese. We present quasiparticle density of states measurements on superconducting AlMn alloys made by current-voltage

Code-division SQUID multiplexing

April 23, 2010
Author(s)
Michael D. Niemack, Kent D. Irwin, Joern Beyer, Hsiao-Mei Cho, William B. Doriese, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale
Multiplexed superconducting quantum interference device (SQUID) readout systems are a critical technology for measuring large arrays of superconducting transition-edge sensor (TES) detectors. Current successful SQUID multiplexing architectures are

Superconductor Science and Technology

February 22, 2010
Author(s)
Kent D. Irwin, Michael D. Niemack, Joern Beyer, Hsiao-Mei Cho, William B. Doriese, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale
Multiplexed superconducting quantum interference device (SQUID) amplifiers have recently enabled the deployment of kilopixel arrays of superconducting transition-edge sensor (TES) detectors on a variety of receivers for astrophysics. Existing multiplexing

Time-of-flight mass spectrometry with latching Nb meander detectors

June 1, 2009
Author(s)
Brian Estey, James A. Beall, Gene C. Hilton, Kent D. Irwin, Daniel R. Schmidt, Joel N. Ullom, Robert E. Schwall
Mass Spectrometry is widely used for protein characterization, structural virology, drug discovery, and clinical chemistry. However the detection efficiency of existing detectors for mass spectrometry degrades rapidly as mass is increased and is only ~10-5

High resolution X-ray transition-edge sensor cooled by tunnel junction refrigerators and operated above the transition temperature

April 21, 2008
Author(s)
Nathan A. Tomlin, Galen C. O\'Neil, James A. Beall, Gene C. Hilton, Kent D. Irwin, Daniel R. Schmidt, Leila R. Vale, Joel N. Ullom
We demonstrate cooling of an X-ray transition-edge sensor (TES) using solid-state refrigerators based on normal-metal / insulator / superconductor (NIS) tunnel junctions. We are able to operate the TES at a bath temperature of 260 mK, which is 75 mK above

Density of states measurements of Al lightly doped with Mn

January 29, 2008
Author(s)
Galen O'Neil, Dan Schmidt, Nathan A. Tomlin, Joel Ullom, Kent D. Irwin, Anthony S. Williams, Gerry Arnold, Steve T. Ruggiero
Al lightly doped with Mn is a tunable superconductor, potentially useful in normalmetal/insulator/superconductor refrigerators. The superconducting transition temperature varies with Mn concentration and the density of states is like a BCS superconductor

A TDMA Hybrid SQUID Multiplexer

January 25, 2008
Author(s)
Carl D. Reintsema, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Dan Schmidt, Joel Ullom, Leila R. Vale, Yizi Xu
We have developed a multiplexed read-out for transition edge sensors based on a hybrid time- and frequency-domain basis set, similar to that used in time-division multiple-access (TDMA) mobile phones. The hybrid basis set uses bandwidth more efficiently

Large array of multiplexed gamma-ray microcalorimeters for nuclear-materials analysis

January 24, 2008
Author(s)
W.Bertrand (Randy) Doriese, Joel Ullom, James A. Beall, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, Kent D. Irwin, John Mates, Carl D. Reintsema, Dan Schmidt, Leila R. Vale, Yizi Xu, Barry L. Zink, Michael W. Rabin, Minesh K. Bacrania, Stephen Lamont, Andrew Hoover, Clifford R. Rudy, Duc Vo, C. K. Stahle, Kevin R. Boyce, Larry E. Brown, Jonathan M. King, F. S. Porter
We are developing a gamma-ray spectrometer for the analysis of nuclear materials based on an array of superconducting transition-edge-sensor microcalorimeters. The instrument includes eight columns of time-division-SQUID multiplexing circuitry capable of

Operation of an X-ray transition-edge sensor cooled by tunnel junction refrigerators

January 19, 2008
Author(s)
Nathan A. Tomlin, James A. Beall, Gene C. Hilton, Kent D. Irwin, Galen O'Neil, Dan Schmidt, Leila R. Vale, Joel Ullom
We demonstrate successful cooling of an X-ray transition-edge sensor (TES) using solid-state refrigerators based on normal-metal/insulator/superconductor (NIS) tunnel junctions. Above the TES transition temperature (Tc), we use Johnson noise thermometry to

Multiplexed microcalorimeter arrays for precision measurements from microwave to gamma-ray wavelengths

August 21, 2007
Author(s)
Joel Ullom, W.Bertrand (Randy) Doriese, James A. Beall, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, Kent D. Irwin, Terrence J. Jach, John Mates, Nathan A. Tomlin, Galen O'Neil, Carl D. Reintsema, Nicholas Ritchie, Dan Schmidt, Leila R. Vale, Yizi Xu, Barry L. Zink, Andrew Hoover, Clifford R. Rudy, Derek Tournear, Duc Vo, Michael W. Rabin
Cryogenic microcalorimeters are a promising technology for ultrasensitive measurements of electromagnetic radiation from microwave to gamma-ray wavelengths. Cryogenic microcalorimeters derive their exquisite sensitivity from the minimal thermal noise at

Normal Metal-insulator-superconductor Junction Technology for Bolometers

April 15, 2006
Author(s)
Dan Schmidt, William Duncan, Kent D. Irwin, Konrad Lehnert, Nathan A. Tomlin, Joel Ullom
Normal metal-insulator-superconductor tunnel junctions are candidates for large-format arrays of ultra-low noise equivalent power bolometers. Using a wafer scale process we have fabricated devices with required the sub $\mu}$m$^3}$ volumes and ohmic