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Search Publications by: Leticia Pibida (Fed)

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Displaying 26 - 50 of 88

Standardization of I-124 by three liquid scintillation-based methods

August 9, 2019
Author(s)
Denis E. Bergeron, Leticia S. Pibida, Brian E. Zimmerman, Jeffrey T. Cessna, Ryan P. Fitzgerald
A solution of 124I was standardized for activity by 4πβ(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting, with confirmatory measurements by triple-to-double coincidence ratio (TDCR) and CIEMAT-NIST efficiency tracing (CNET) liquid scintillation

Confirming a Performance Threshold with a Binary Experimental Response

July 15, 2019
Author(s)
Dennis D. Leber, Leticia S. Pibida, Alexander L. Enders
Often, experimenters wish to confirm that a test artifact meets some predefined, fixed performance criterion or claim. For example: does the newly formulated pharmaceutical reduce the disease rate by 10 %; will the composite overwrapped pressure vessel

PRIMARY STANDARDIZATION OF THE MASSIC ACTIVITY OF A PROTACTINIUM-233 SOLUTION

August 23, 2018
Author(s)
Ryan P. Fitzgerald, Leticia S. Pibida
Protactinium-233 (233Pa) is used as a tracer for radiochemical analysis and is of particular interest as an isotope dilution mass spectrometry (IDMS) spike for 231Pa/235U radio- chronometry. To this end, we present massic activity determinations by two

Measurements of scatter peaks in 137Cs and 60Co sources

June 28, 2018
Author(s)
Leticia Pibida
The results of the testing of radiation detection instruments with radionuclide identification capabilities will depended on the sources used for the tests. High resolution spectra need to be acquired to determine all the observable peaks in the source

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 LaRosa, Brian Zimmerman, Leticia Pibida, Denis 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
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