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Ronald Tosh (Fed)

Ron Tosh is a physicist in the Radiation Physics Division working in the Dosimetry Group on standards and instrumentation for absorbed dose. He joined NIST in 2004 after several years as a sales engineer for National Instruments (now NI). Prior to that, he did experimental research in molecular-beam scattering as a postdoc in the Department of Chemistry and Biochemistry at the University of Delaware. He received both M.S. and Ph.D. in physics from the Department of Physics and Astronomy at the University of Pittsburgh, with a research emphasis in atomic physics and gaseous electronics.

Current projects at NIST include development of calorimetry standards for absorbed dose in beams of gamma rays, x-rays, electrons and protons used in medicine and industry. Research activities are focused on dosimetry in radiation fields with large spatial gradients and high dose rates, with applications in radiotherapy, irradiation of surfaces, and radiosensitivity of semiconductor microdevices and biological systems.

Highlights

Photonic Radiation Sensors Survive Huge Doses Undamaged
Calibrating Cancer Radiotherapy Beams Using Light and Sound
Using Calorimetry to Estimate Absorbed Dose from CT Scans

Projects and Research

Photonic Dosimetry
Remote Sensing Methods for Imaging Dose to Water
Electron and Proton Absorbed-Dose-to-Water Primary Standards

Awards

U.S. Department of Commerce Silver Medal – for contributions to standards for x-ray scanning systems used in transportation security screening.

Publications

Calorimetry in Computed Tomography Beams

Author(s)
Heather H. Chen-Mayer, Ronald Tosh, Fred B. Bateman, Paul Bergstrom, Brian E. Zimmerman
A portable calorimeter for direct realization of absorbed dose in medical computed tomography (CT) procedures was constructed and tested in a positron emission

MICROMETROLOGY IN PURSUIT OF QUANTUM RADIATION STANDARDS

Author(s)
Ryan P. Fitzgerald, Zeeshan Ahmed, Denis E. Bergeron, Nikolai Klimov, Dan Schmidt, Ronald Tosh
With the recent redefinition of the SI base units in terms of constants of nature, the race is on to maximize achievable precision by developing primary

Patents (2018-Present)

Graph inset shows plots of measurements obtained at NIST exhibiting linear temperature dependence for Fiber Bragg Gratings and Photonic Ring Resonators on a Chip.

Photonic Calorimeter

NIST Inventors
Ronald Tosh , Zeeshan Ahmed , Ryan P. Fitzgerald and Nikolai Klimov
The calorimeter uses embedded, nanofabricated photonic sensors to enable micro-scale spatial resolution of dose (energy) distributions and gradients. It presents an alternative to thermistors used in conventional calorimeters for radiation dosimetry, comprising photonic sensors for in-situ dose and
An array of photonic dosimeters subjected to ionizing radiation.

Photonic Dosimeter

NIST Inventors
Ronald Tosh , Zeeshan Ahmed , Ryan P. Fitzgerald and Nikolai Klimov
NIST scientists have developed a photonic device whose resonance characteristics (such as quality factor, peak position, and free spectral range) change in a predictable way in response to the interaction of radiation with the sensor and/or its surroundings. The invention consists of one or more
Created September 24, 2019, Updated December 8, 2022
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