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Search Publications by: Joel Ullom (Fed)

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Displaying 176 - 200 of 350

Microcalorimeter Spectroscopy at High Pulse Rates: a Multi-Pulse Fitting Technique

August 24, 2015
Author(s)
Joseph W. Fowler, Bradley K. Alpert, William B. Doriese, Young Il Joe, Galen C. O'Neil, Cherno Jaye, Joel N. Ullom, Daniel A. Fischer, Daniel S. Swetz
Transition edge sensor microcalorimeters can measure x-ray and gamma-ray energies with very high energy resolution and high photon-collection efficiency. For this technology to reach its full potential in future x-ray observatories, each sensor must be

Macroscopic Subkelvin Refrigerator Employing Superconducting Tunnel Junctions

August 10, 2015
Author(s)
Xiaohang NMN Zhang, Peter J. Lowell, Brandon L. Wilson, Galen C. O'Neil, Joel N. Ullom
In this paper, we demonstrate a general-purpose macroscopic refrigerator based on the transport of hot electrons through superconducting tunnel junctions. Our refrigerator is intended to provide access to temperatures below those accessible using pumped

Thermal Conductance Engineering for High-Speed TES Microcalorimeters

July 22, 2015
Author(s)
James P. Hays-Wehle, Daniel R. Schmidt, Joel N. Ullom, Daniel S. Swetz
Many current and future applications for superconducting transition-edge sensor (TESmicrocalorimeters require significantly faster pulse-response than is currently available. X-ray spectroscopy experiments at next-generation synchrotron light sources need

High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

May 1, 2015
Author(s)
W.Bertrand (Randy) Doriese, Joseph Fowler, Daniel Swetz, Cherno Jaye, Daniel A. Fischer, Carl D. Reintsema, Douglas Bennett, Leila R. Vale, Gene C. Hilton, Dan Schmidt, Joel Ullom, Jens Uhlig, Ujjwal Mandal, Galen O'Neil, Luis Miaja Avila, Young I. Joe, wilfrid fullagar, Fredrick P. Gustafsson, Dharma Kurunthu, Villy Sundstrom
X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low

Measurement of the 240Pu/239Pu Mass Ratio Using a Transition-Edge-Sensor Microcalorimeter for Total Decay Energy Spectroscopy

February 27, 2015
Author(s)
Daniel R. Schmidt, Douglas A. Bennett, James P. Hays-Wehle, Daniel S. Swetz, Joel N. Ullom, Andrew Hoover, Mark Croce, Michael W. Rabin, Evelyn Bond, Terry Holesinger, Gerd Kunde, Laura Wolfsbereg
We have developed a new category of sensor for measurement of the 240Pu/239Pu mass ratio from aqueous solution samples with advantages over existing methods. Aqueous solution plutonium samples were evaporated and encapsulated inside of a gold foil absorber

Integration of TES microcalorimeters with microwave SQUID multiplexed readout.

December 22, 2014
Author(s)
Douglas A. Bennett, John A. Mates, Johnathon D. Gard, Andrew Hoover, Micheal Rabin, Carl D. Reintsema, Daniel R. Schmidt, Leila R. Vale, Joel N. Ullom
The demonstration of a microwave SQUID multiplexed readout of transition-edge sensor (TES) microcalorimeters has the potential to dramatically expand the scale of arrays of TESs. In this manuscript we discuss recent work to develop an instrument for high

Phase-slip lines as a resistance mechanism in transition-edge sensors

January 27, 2014
Author(s)
Douglas A. Bennett, Daniel R. Schmidt, Daniel S. Swetz, Joel N. Ullom
The fundamental mechanism of resistance in voltage-biased superconducting films is poorly understood despite its importance as the basis of transition-edge sensors (TESs). TESs are utilized in state-of- the-art microbolometers and microcalorimeters

Sub-100 mK cooling using normal-metal?insulator?superconductor tunnel junctions

December 15, 2013
Author(s)
Peter J. Lowell, Galen C. O'Neil, Jason M. Underwood, Xiaohang NMN Zhang, Joel N. Ullom
Normal-metal∖insulator∖superconductor (NIS) junctions can be used as solid-state refrigerators since the hottest electrons preferentially tunnel from the normal metal into the superconductor. In this paper, we present NIS junctions optimized to cool

Identification and elimination of anomalous thermal decay in gamma-ray microcalorimeters

November 18, 2013
Author(s)
Robert D. Horansky, Douglas A. Bennett, Daniel R. Schmidt, Barry L. Zink, Joel N. Ullom
Microcalorimeter detectors rely on superconducting components and cryogenic temperatures to provide over an order-of-magnitude improvement in energy resolution compared to semiconducting sensors. Resolution improvements impact fields from gamma-ray

High resolution gamma-ray spectroscopy with a microwave-multiplexed TES array

November 11, 2013
Author(s)
Omid Noroozian, John A. Mates, Douglas A. Bennett, Justus A. Brevik, Joseph W. Fowler, Jiansong Gao, Robert D. Horansky, Kent D. Irwin, Daniel R. Schmidt, Joel N. Ullom, Zhao Kang
We demonstrate the first gamma-ray spectroscopy with a microwave-multiplexed two-pixel TES(transition-edge sensor) array. We measured a $^{153}$Gd photon source and achieved an energy resolution of 63 eV full-width-at-half-maximum (FWHM) at 97 keV and an

Lattice damage in superconducting microcalorimeter detectors

June 3, 2013
Author(s)
Robert D. Horansky, Joel N. Ullom, Michael W. Rabin
There is currently significant interest in using superconducting detectors for measurement of ion kinetic energies. Unprecedented resolution is possible with an order of magnitude improvement over semiconductors. Superconducting detectors are now able to