Gamma-ray spectrometry is a widely used technique to quantify the presence of numerous radionuclides in environmental samples. In this work, we describe a methodology for efficiency calibration of four well-type germanium detectors and their use for the determination of low-level activities of gamma emitters in sediment samples. An experimental efficiency calibration for each detector was built with three materials for 17 energies, ranging from 46.5 keV to 1460 keV. For efficiency transfer to different geometries and sample types, we used the effective solid angle approach (ET-Ω method). Final calibrations were calculated for all detectors, several counting geometries, and elemental composition of selected sample types. Calibrations were validated with six reference materials. This methodology allowed to reliably analyze nine gamma emitters (Pb, Am, Th, Ac, Pb, Tl, Cs, Cs and K) in sediment samples. Using these calibrations, gamma emitter profiles of sediment cores from contrasting aquatic systems (lake, intertidal, marine and deep-sea areas) provided reliable profiles of Pb and artificial radionuclides useful for dating and stratigraphic interpretation. A protocol to implement this methodology is also presented.
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http://dx.doi.org/10.1016/j.jenvrad.2020.106385 | DOI Listing |
Indian J Nucl Med
November 2024
Center for Research and Production of Radioisotopes, Dalat Nuclear Research Institute, Vietnam Atomic Energy Institute (VINATOM), Da Lat City, Lam Dong Province, Vietnam.
Aims: This study aimed to evaluate the principal technical characteristics of a well-type gas-filled ionization chamber dose calibrator used in measuring radiopharmaceutical activity, namely accuracy, repeatability, and linearity. Furthermore, this work also explored the correlation between the device's response and the position and volume of the radiopharmaceutical I-131.
Materials And Methods: Experimental measurements were conducted on the ATOMLAB 500 dose calibrator using NIST traceable Cs-137 source to determine the accuracy and repeatability.
J Appl Clin Med Phys
August 2024
Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Purpose: For the custom-built construction of eye plaques, the iodine (I-125) seeds of different source strengths are recycled in our eye plaque program. To return I-125 seeds to the correct lot, we developed a novel 3D-printed conical plaque QA holder for relative assay for eye plaques.
Materials And Methods: A universal 3D-printed conical plaque holder was designed to accommodate six plaque sizes and fit reproducibly in a well-type dose calibrator.
Appl Radiat Isot
July 2024
Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Appl Radiat Isot
March 2024
National Institute of Standards and Technology, 100 Bureau Dr, MS 8462, Gaithersburg, MD, 20899-8462, USA. Electronic address:
Absolute gamma-ray emission intensities for 36 characteristic gamma rays from the decay of Ra, Pb, and their progeny were determined by measuring sources calibrated for activity by means of primary methods based on well-defined high-purity germanium (HPGe) detectors at both NIST and NPL. Results from the two laboratories agree with recent data evaluations, except for gamma rays with low emission intensities. The decay schemes have been re-balanced based on the new results.
View Article and Find Full Text PDFAppl Radiat Isot
March 2024
Vinca Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Mike Petrovica Alasa 12-14, 11351 Vinča, Belgrade, Serbia; Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia.
Source strength measurements are of critical importance for brachytherapy and are often performed in hospitals using well-type chambers. Quality assurance and quality control procedures should be implemented, but that may prove difficult in some hospitals due to the lack of equipment or metrological support. A study was conducted to investigate the status of the measurement equipment in Serbian hospitals and to organize an intercomparison campaign using a hospital Ir source.
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