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Joseph Fowler (Assoc)

Joseph Fowler is an experimental physicist in the Quantum Sensors Group at the NIST Boulder Laboratories. He joined NIST after a period working with arrays of superconducting microwave-frequency detectors in the Atacama Cosmology Telescope. His research focuses on the use of superconducting x-ray and gamma-ray sensors with very high energy resolution. He specializes in data analysis and scientific computing, including the complex software required to operate arrays of high-speed sensors and the analytic tools required for extraction of accurate energy values from them. He is involved in projects to make world-leading metrological measurements of x-ray emission and absorption processes; 3-dimensional x-ray computed tomography of objects at 100 nm spatial resolution; and many other measurements with superconducting sensors at NIST, x-ray synchrotrons, and radio-isotope analysis labs. He has written or co-authored over 200 publications in spectroscopy, observational cosmology, statistical analysis, and cosmic-ray measurements. He has contributed to work by NIST teammates that has won NIST Gold, Silver, and Bronze Medals.

Research Interests

  • Metrology of fundamental x-ray parameters such as x-ray fluorescence emission.
  • Nanometer-scale x-ray computed tomography of microelectronics.
  • Development of scientific computing software for high-precision analysis of data from superconducting microcalorimeters.
  • New applications of precision x-ray spectroscopy.

Awards

  • NIST Physical Measurement Laboratory Distinguished Associate (2015, 2017, and 2020)

Publications

A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray

Author(s)
Paul Szypryt, Nathan J. Nakamura, Dan Becker, Douglas Bennett, Amber L. Dagel, W.Bertrand (Randy) Doriese, Joseph Fowler, Johnathon Gard, J. Zachariah Harris, Gene C. Hilton, Jozsef Imrek, Edward S. Jimenez, Kurt W. Larson, Zachary H. Levine, John Mates, Daniel McArthur, Luis Miaja Avila, Kelsey Morgan, Galen O'Neil, Nathan Ortiz, Christine G. Pappas, Dan Schmidt, Kyle R. Thompson, Joel Ullom, Leila R. Vale, Michael Vissers, Christopher Walker, Joel Weber, Abigail Wessels, Jason W. Wheeler, Daniel Swetz
We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines

Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon

Author(s)
Douglas Bennett, W.Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Johnathon Gard, Gene C. Hilton, Kelsey Morgan, Galen O'Neil, Carl D. Reintsema, Dan Schmidt, Daniel Swetz, Joel Ullom, Takuma Okumura
To test the bound-state quantum electrodynamics (BSQED), we have performed high precision x- ray spectroscopy of the 5g→4f and 5f→4d transitions (BSQED

Patents (2018-Present)

X-Ray Spectrometer

X-Ray Spectrometer

NIST Inventors
Kevin L. Silverman , Carl D. Reintsema , Galen O'Neil , Luis Miaja Avila , Daniel Swetz , W.Bertrand (Randy) Doriese , Dan Schmidt , Bradley Alpert , Joseph Fowler , Joel Ullom , Ralph Jimenez and Gene C. Hilton
This invention includes: an x-ray plasma source that produces primary x-rays; an x-ray optic that transmits and focuses the primary x-ray onto a sample jet from which fluorescence x-ray are emitted; and a microcalorimeter array detector that measures the energy of the incoming fluorescence x-rays
Created June 6, 2019, Updated October 11, 2023