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Search Publications by: Leticia Pibida (Fed)

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Displaying 26 - 50 of 84

Standardization of 64Cu activity

May 25, 2018
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Leticia S. Pibida, Brian E. Zimmerman
The complex decay scheme that makes 64Cu promising as both an imaging and therapeutic agent in medicine also makes the absolute measurement of its activity challenging. The National Institute of Standards and Technology (NIST) has completed a primary

Activity measurements of the radionuclides 18F and 64Cu for the NIST, USA in the ongoing comparisons BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64

January 1, 2018
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Leticia S. Pibida, Brian E. Zimmerman, Carine Michotte, Manuel Nonis, Andrew Fenwick, Kelly Ferreira, John Keightley
In 2016, comparisons of activity measurements of 18F and 64Cu using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST, USA). This is the first SIRTI comparison for

Natural Uranium Radioactivity Solution Standard: SRM 4321d

December 27, 2017
Author(s)
Ronald Colle, Lizbeth Laureano-Perez, Svetlana Nour, Jerome J. LaRosa, Brian E. Zimmerman, Leticia S. Pibida, Denis E. Bergeron
A new natural uranium solution standard has been produced and will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material 4321d. The standard is certified for the massic activities of 234U, 235U, and

Evidence against solar influence on nuclear decay constants

August 24, 2016
Author(s)
Denis E. Bergeron, Ryan P. Fitzgerald, Leticia S. Pibida, Stefaan Pomme
The exponential decay of radionuclides as a function of time is a cornerstone of nuclear physics and radionuclide metrology. Decay constants for spontaneous radioactive decay are considered invariable in time and space. This convenient trait allows

Revision of the NIST Standard for 223Ra: New Measurements and Review of 2008 Data

July 1, 2015
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Leticia S. Pibida
After discovering a discrepancy in the transfer standard currently being disseminated by the National Institute of Standards and Technology (NIST), we have performed a new primary standardization of the alpha-emitter 223Ra using Live-timed Anticoincidence

Determination of photon emission probabilities for the main gamma-rays of 223Ra in equilibrium with its progeny

March 11, 2015
Author(s)
Leticia S. Pibida, Brian E. Zimmerman, Ryan P. Fitzgerald, Lynne E. King, Jeffrey T. Cessna, Denis E. Bergeron
The currently published 223Ra gamma-ray emission probabilities display a wide variation in the values depending on the source of the data. The National Institute of Standards and Technology performed activity measurements on a 223Ra solution that was used

Scaling of Testing Speed for Different Source-to-Detector Distances

February 13, 2015
Author(s)
Bruce R. Norman, Anne L. Sallaska, Leticia Pibida
Several American National Standard Institute/Institute of Electrical and Electronics Engineers (ANSI/IEEE) and International Electrotechnical Commission (IEC) standards were developed for radiation detection systems used for homeland security applications

A New NIST Primary Standardization of 18F

February 1, 2014
Author(s)
Ryan P. Fitzgerald, Brian E. Zimmerman, Denis E. Bergeron, Jeffrey T. Cessna, Leticia S. Pibida, Denise S. Moreira
A new primary standardization of 18F by NIST is reported. The standard is based on live-timed beta- gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST 3H efficiency

ITRAP+10 Spectroscopic Radiation Portal Monitor Testing

November 14, 2013
Author(s)
Anne L. Sallaska, Leticia S. Pibida, Huaiyu H. Chen-Mayer, Luc Murphy, Christina Ward
The Illicit Trafficking Radiation Assessment Program (ITRAP+10) is an international effort of the Department of Homeland Security’s Domestic Nuclear Detection Office (DHS/DNDO), the European Commission’s Joint Research Center (EC-JRC), and the

Justification of Shielding Requirements for Plutonium Sources

September 12, 2012
Author(s)
Leticia S. Pibida, Michael P. Unterweger
This report provides a justification for shielding plutonium sources when testing radiation detection instruments against standard performance requirements and test methods. The use of copper as a shielding material is proposed to provide comparable test

NIST Handbook 150-23, 2010 ed., National Voluntary Laboratory Accreditation Program (NVLAP) Homeland Security Applications: Radiation Detection Instruments

April 13, 2010
Author(s)
Betty A. Sandoval, Leticia S. Pibida, Gordon Gillerman, Michael P. Unterweger
NIST Handbook 150-23, NVLAP Homeland Security Applications: Radiation Detection Instruments, presents the technical requirements and guidance for the accreditation of laboratories that test radiation detection instruments used in homeland security

A New Primary Standardization of Th-229

January 7, 2010
Author(s)
Ryan P. Fitzgerald, Lizbeth Laureano-Perez, Michelle M. Hammond, Leticia S. Pibida, Svetlana Nour, Brian E. Zimmerman
The National Institute of Standards and Technology (NIST) has certified a high-purity Th-229 Standard Reference Material as SRM 4328C, based on live-timed 4-pi alpha,beta-gamma anticoincidence counting (LTAC) of the equilibrium solution. The LTAC system

Half-life Measurements of Sr82

January 30, 2009
Author(s)
Leticia S. Pibida, Ryan P. Fitzgerald, Michael P. Unterweger, Michelle M. Hammond, Daniel B. Golas
Half-life measurements of 82Sr were performed at the National Institute of Standards and Technology (NIST) using gamma-ray spectrometry and a 4 pressurized ionization chamber. The 82Sr half-life was determined to be 25.36 ± 0.03 days (k=1) using the