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Search Publications by: Joel Ullom (Fed)

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Displaying 126 - 150 of 173

Two-Body Models for Analyzing Complex Impedance

July 24, 2009
Author(s)
Douglas A. Bennett, Robert D. Horansky, Joel N. Ullom
Complex impedance is an important and widely used technique for characterizing microbolometers and microcalorimeters. Often, complex impedance data from actual devices does not fit the simple one-body model of a TES microcalorimeter. In this paper we will

Anomalous thermal behavior in microcalorimeter gamma-ray detectors

July 20, 2009
Author(s)
Robert D. Horansky, James A. Beall, Kent D. Irwin, Joel N. Ullom
Improving the resolution of gamma-ray detectors is important for many fields, including determinations of the Lamb shift in atoms with high atomic numbers , nuclear treaty verification , and environmental monitoring. High-purity germanium detectors are

Improved Isotopic Analysis With a Large Array of Gamma-Ray Microcalorimeters

June 30, 2009
Author(s)
Nikhil Jethava, Joel N. Ullom, Douglas A. Bennett, William B. Doriese, James A. Beall, Gene C. Hilton, Robert D. Horansky, Kent D. Irwin, Eric Sassi, Leila R. Vale, Minesh K. Bacrania, Andrew Hoover, P. J. Karpius, Michael W. Rabin, Clifford R. Rudy, Duc T. Vo
We present results from the largest array of gamma-ray microcalorimeters operated to date. The microcalorimeters consist of Mo/Cu transition-edge sensors with attached Sn absorbers. The detector array contains 66 pixels each with an active area 2.25 mm 2

Improved Isotopic Analysis with a Large Array of Gamma-ray Microcalorimeters

June 30, 2009
Author(s)
Nikhil Jethava, Joel N. Ullom, Douglas A. Bennett, William B. Doriese, James A. Beall, Gene C. Hilton, Robert D. Horansky, Kent D. Irwin, Eric Sassi
We present results from the largest array of gamma-ray microcalorimeters operated to date. The microcalorimeters consist of Mo/Cu transition-edge sensors with attached Sn absorbers. The detector array contains 66 pixels each with an active area 2.25 mm2

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

Ultra-high resolution alpha particle spectroscopy using calorimetry

September 23, 2008
Author(s)
Robert D. Horansky, Joel N. Ullom, James A. Beall, Gene C. Hilton, Kent D. Irwin, Don Dry, Beth Hastings, Stephen Lamont, Clifford R. Rudy, Michael W. Rabin
Calorimetry has been used since the late 1700?s to measure the heat output of physical processes ranging from chemical reactions to the respiration of organisms . Calorimetry is performed by measuring the temperature change caused by heat release into a

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

Analysis of Nuclear Material by Alpha Spectroscopy with a Transition-Edge Microcalorimeter

January 26, 2008
Author(s)
Rob Horansky, Joel Ullom, James A. Beall, Gene C. Hilton, Kent D. Irwin, Leila R. Vale, Don Dry, Stephen Lamont, Clifford R. Rudy, Michael W. Rabin
We present measurements from a cryogenic microcalorimeter designed to detect alpha particles. The enhanced resolution of microcalorimeter alpha detectors will provide new capabilities for actinide analysis. We demonstrate a spectral resolution of 2.4 keV

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

Materials Analysis with Cryogenic Sensors

January 24, 2008
Author(s)
Joel N. Ullom
Low temperature photon detectors are increasingly attractive tools for materials analysis. Their range of applications has broadened from early work on x-ray fluorescence and now spans the electromagnetic spectrum from terahertz to gamma-ray energies. In

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

A 14-pixel, multiplexed array of gamma-ray microcalorimeters with 47 eV energy resolution at 103 keV

May 9, 2007
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, Leila R. Vale, Yizi Xu, Barry L. Zink, Andrew Hoover, Michael W. Rabin, Clifford R. Rudy, Duc Vo
We present a prototype for a high-energy-resolution, high-count-rate, gamma-ray spectrometer intended for nuclear forensics and international nuclear safeguards. The prototype spectrometer is an array of 14 transition-edge-sensor microcalorimeters with an

Demonstration and modeling of an array-compatible TES microcalorimeter gamma-ray detector with 42 eV energy resolution at 103 keV

September 20, 2006
Author(s)
Barry L. Zink, Joel Ullom, James A. Beall, Kent D. Irwin, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Rob Horansky, Carl D. Reintsema, Leila R. Vale
We describe a microcalorimeter gamma-ray detector with measured energy resolution of 42 eV full width at half maximum for 103 keV photons. This detector consists of a thermally isolated superconducting transition-edge thermometer and a superconducting bulk

Erbium-doped Gold Sensor Films for Magnetic Microcalorimeter X-ray Detectors*

April 17, 2006
Author(s)
Barry L. Zink, Kent D. Irwin, Gene C. Hilton, Joel Ullom, David P. Pappas
We briefly review the principles of a magnetic microcalorimeter x-ray detector and the requirements for fabricating an array of these sensors, which include a paramagnetic sensor fabricated with thin-film techniques. We discuss two methods for depositing

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

Optimization of Transition-Edge Calorimeter Performance

April 15, 2006
Author(s)
Joel N. Ullom, James A. Beall, William B. Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Galen C. O'Neil, Carl D. Reintsema, Leila R. Vale, Barry L. Zink
Calorimeters that exploit the superconducting-to-normal transition are used to detect individual photons from near-infrared to γ-ray wavelengths. Across this wide range, absorption efficiency, speed, and energy resolution are key performance parameters

Microwave SQUID multiplexers for low-temperature detectors

January 10, 2006
Author(s)
Kent D. Irwin, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, Gene C. Hilton, John Mates, Carl D. Reintsema, Dan Schmidt, Joel Ullom, Leila R. Vale, Barry L. Zink, Konrad Lehnert
We report on the development of a SQUID multiplexer operated at microwave frequencies. This multiplexer can accommodate any detector that can be read out with SQUIDs, including transition-edge sensors, magnetic calorimeters, and superconductor-insulator

Toward kilopixel arrays: 3.8 eV microcalorimeter resolution in 8-channel SQUIDmultiplexer

January 10, 2006
Author(s)
W.Bertrand (Randy) Doriese, James A. Beall, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Carl D. Reintsema, Joel Ullom, Leila R. Vale, Yizi Xu
Over the past several years, NIST has developed a SQUID time-division multiplexer (TDM) to read out large arrays of transition-edge sensors (TESs). The NIST TDM architecture has been successful in a number of submillimeterand millimeter-wave applications

Development of a solid-state 100 mK refrigerator for user-supplied microelectronics

January 4, 2006
Author(s)
Nathan A. Tomlin, William Duncan, James A. Beall, Gene C. Hilton, Kent D. Irwin, Dan Schmidt, Joel Ullom
Solid-state refrigerators based on normal metal/insulator/superconductor tunnel junctions are now a practical means of cooling from pumped 3He bath temperatures to near 100 mK. While integration of NIS refrigerators with transition-edge sensors is underway

Fabrication of Prototype Imaging Arrays for SCUBA-2

January 4, 2006
Author(s)
Gene C. Hilton, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Kent D. Irwin, Carl D. Reintsema, Joel Ullom, Leila R. Vale, Yizi Xu, Barry L. Zink, William Parkes, Andrew S. Bunting, Camilla Dunare, Alan Gundlach, T. Stevenson, Anthony Walton, Eric Schulte, Elizabeth Corrales, Joseph P. Sienicki, Dan Bintley, Peter Ade, Rashmi Sudiwala, Adam L. Woodcraft, Mark Halpern, Wayne Holland, Damian Audley, Michael MacIntosh
Prototype imaging sub-arrays for SCUBA-2 (the Sub-millimeter Common-User Bolometer Array) have been fabricated and tested. The pixel count (1280) of these wafer-scale imagers are significantly larger than any other low-temperature detectors produced to

Optimized Transition-Edge X-ray Microcalorimeter with 2.4 eV Energy Resolution at 5.9 keV

November 1, 2005
Author(s)
Joel Ullom, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Carl D. Reintsema, Leila R. Vale
We present measurements from a series of transition- edge x-ray microcalorimeters designed for optimal energy resolution. We used the geometry of the sensors to control their heat capacity and employed additional normal metal features and a perpendicular

Dilute Al-Mn Alloys for Superconductor Tunneling and Other Devices

June 13, 2005
Author(s)
Steve T. Ruggiero, G. B. Arnold, A Williams, Anna Clark, Nathan A. Tomlin, Joel Ullom
We present tunneling results for junctions comprising Mn doped Al films produced by sputter deposition, with Mn oncentrations in the range of 5000 ppm. Our results for SIS, IS, and NIS junctions demonstrate that Al-Mn alloys can serve as both