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Search Publications by: Lizbeth Laureano-Perez (Fed)

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Displaying 1 - 22 of 22

Liquid scintillation efficiencies, gamma-ray emission intensities, and half-life for Gd-153

November 9, 2023
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Gulakhshan Hamad, Lizbeth Laureano-Perez, Leticia Pibida, Brian E. Zimmerman
Gadolinium-153 was standardized for activity by live-timed anticoincidence counting and an ampoule was submitted to the international reference system (SIR). Absolute emission intensities for the main γ rays were determined with calibrated high-purity

Preparation and Standardization of 229Th SRM 4328d

February 24, 2023
Author(s)
Ronald Colle, Lizbeth Laureano-Perez, Morgan DiGiorgio
The certified massic activity for 229Th in SRM 4328d was obtained by 4παβ liquid scintillation (LS) counting by comparative measurements in 2022 against SRM 4328c. Both SRMs were prepared from the identical 2007 229Th stock solution. SRM 4328c was

Primary standardization of 212Pb activity by liquid scintillation counting

September 22, 2022
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Lizbeth Laureano-Perez, Leticia Pibida, Brian E. Zimmerman
An activity standard for 212Pb in equilibrium with its progeny was realized, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. A Monte Carlo-based approach to estimating uncertainties due to nuclear decay data

BIPM comparison BIPM.RI(II)-K1.Gd-153 of activity measurements of the radionuclide 153Gd to include the 2020 result of the NIST (United States)

November 25, 2021
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Lizbeth Laureano-Perez, Leticia Pibida, Carine Michotte, S Courte, M Nonis, R Coulon, S Judge
Since 1988, 3 laboratories have submitted 5 samples of 153Gd to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Gd-153. Recently, the NIST

Primary standardization of Ra-224 activity by liquid scintillation counting

October 11, 2019
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Lizbeth Laureano-Perez, Ronald Colle, Leticia S. Pibida, Elisa Napoli
A standard for 224Ra activity has been developed, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. The standard was confirmed by efficiency tracing and 4παβ(LS)-γ(NaI(Tl)) anticoincidence counting, as well as by 4πγ

Preparation and calibration of a Protactinium-231 reference material

August 22, 2019
Author(s)
Richard Essex, Ross W. Williams, Kerri C. Treinen, Ronald Colle, Ryan P. Fitzgerald, Raphael Galea, John Keightley, Jerome LaRosa, Lizbeth Laureano-Perez, Svetlana Nour, Leticia Pibida
A 231Pa reference material has been characterized for amount of Pa. This reference material is primarily intended for calibration of 233Pa tracers produced for 231Pa - 235U model age measurements associated with nuclear forensics and nuclear safeguards

New determination of the 229Th half-life

July 23, 2018
Author(s)
Richard Essex, Jacqueline L. Mann, Ronald Colle, Lizbeth Laureano-Perez, Megan E. Bennett, Heather Dion, Ryan P. Fitzgerald, Amy M. Gaffney, Amelie Hubert, Robert E. Steiner, Ross W. Williams, Alkiviadis Gourgiotis, William S. Kinman
A new determination of the 229Th half-life was made based on measurements of the 229Th massic activity of a high-purity solution for which the 229Th molality had previously been measured. The 229Th massic activity was measured by direct comparison with SRM

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

Results of an International Comparison of Activity Measurements of 68Ge

November 7, 2017
Author(s)
Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Lizbeth Laureano-Perez, Denis E. Bergeron
An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68Ge/68Ga solution. Results for the activity

Comparison of C-14 liquid scintillation counting at NIST and NRC Canada

March 1, 2016
Author(s)
Denis E. Bergeron, Raphael Galea, Lizbeth Laureano-Perez, Brian E. Zimmerman
An informal bilateral comparison of 14C liquid scintillation (LS) counting at the National Research Council of Canada (NRC) and the National Institute of Standards and Technology (NIST) has been completed. Two solutions, one containing 14C-labeled sodium

Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

July 23, 2015
Author(s)
Ronald Colle, Ryan P. Fitzgerald, Lizbeth Laureano-Perez
Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard

The Half-Life of 209Po : Revisited

August 13, 2014
Author(s)
Ronald Colle, Ryan P. Fitzgerald, Lizbeth Laureano-Perez
A substantial 25 % error in the then known and accepted (102  5) year half-life of 209Po was reported on in 2007. This error was detected from decay data from two separate primary standardizations of a 209Po solution standard, which were performed

Standardization of 237Np

December 4, 2013
Author(s)
Lizbeth Laureano-Perez, Ryan P. Fitzgerald, Ronald Colle
The standardization of 237Np was investigated. The certified massic activity for 237Np was obtained by 4 liquid scintillation (LS) counting with correction for the 233Pa daughter using the CIEMAT/NIST efficiency tracing method using a 3H standard

Micelle size effect on Fe-55 Liquid Scintillation Efficiency

December 1, 2013
Author(s)
Denis E. Bergeron, Lizbeth Laureano-Perez
We used efficiency tracing techniques to study the micelle size effect on liquid scintillation counting of the low-energy Auger electron emitter, 55Fe. We determined micelle hydrodynamic diameters for specific LS cocktails via dynamic light scattering, and

Investigation into the Standardization of Tc-99

July 30, 2010
Author(s)
Lizbeth Laureano-Perez, Ronald Colle, Ryan P. Fitzgerald, Brian E. Zimmerman, Lonnie T. Cumberland
The standardization of 99Tc by several primary methods was investigated. This was performed to support a new 99Tc transfer standard that has been developed and will be disseminated by the National Institute of Standards and Technology (NIST) as Standard

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