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Search Publications by: Ronald Tosh (Fed)

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Displaying 1 - 17 of 17

Calorimetry in Computed Tomography Beams

March 10, 2022
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 tomography (PET) CT scanner. The calorimeter consists of two small thermistors embedded in a

MICROMETROLOGY IN PURSUIT OF QUANTUM RADIATION STANDARDS

November 9, 2021
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 standards based on quantum metrology, thereby to realize the Quantum SI. For the becquerel (Bq) and

High-Resolution Ultrasonic Thermometer for Radiation Dosimetry

October 12, 2021
Author(s)
Eugene Malyarenko, Joseph Heyman, Heather H. Chen-Mayer, Ronald Tosh
This paper describes recent developments in the area of high-precision This paper describes recent developments in the area of high-precision ultrasonic thermometry with the potential to provide on-site direct determination of radiation dose and its

On-chip Silicon Photonics Radiation Sensors

September 18, 2019
Author(s)
Nikolai N. Klimov, Zeeshan Ahmed, Lonnie T. Cumberland, Ileana M. Pazos, Ronald E. Tosh, Ryan P. Fitzgerald
We have examined the impact of cobalt-60-ray radiation up to 1 megagray (MGy) absorbed dose on silicon photonic devices. We do not find any systematic impact of radiation on passivated devices, indicating the durability of passivated silicon devices

Assessing Radiation Hardness of Silicon Photonic Sensors.

August 13, 2018
Author(s)
Zeeshan Ahmed, Lonnie T. Cumberland, Ronald E. Tosh, Nikolai N. Klimov, Ileana M. Pazos, Ryan P. Fitzgerald
In recent years silicon photonic platforms have undergone rapid maturation enabling not only optical communication but complex scientific experiments ranging from sensors applications to fundamental physics inquiries. There is con-siderable interest in

Large Area Alpha Sources with a Lip: Integral Counting and Spectral Distortions

August 31, 2017
Author(s)
Lynne E. King, Ryan P. Fitzgerald, Ronald Tosh
The detection efficiency for large area alpha sources with adjustable heights of a raised lip around the edge were measured by 2π gas-filled proportional counter. The variations in low- energy spectral shape were modeled using a Geant4 radiation and charge

Measurements and Standards for Bulk-Explosive Detection

May 31, 2012
Author(s)
Lawrence T. Hudson, Fred B. Bateman, Paul M. Bergstrom, Frank Cerra, Jack L. Glover, Ronaldo Minniti, Stephen M. Seltzer, Ronald E. Tosh
Due to the ease of assembly and leveraged disruptive effect, the improvised explosive device (IED) is the method of choice of today’s terrorist. With more than ten thousand IED incidents annually, and global expenditures for aviation and commercial

Time-resolved radiation beam profiles in water obtained by ultrasonic tomography

December 31, 2010
Author(s)
Eugene Malyarenko, Joseph Heyman, Heather H. Chen-Mayer, Ronald Tosh
This paper presents a practical ultrasonic system for near real-time imaging of spatial temperature distributions in water caused by absorption of radiation. Initial testing with radiation from a highly attenuated infrared lamp demonstrates that the system