Development and applications of the NSF-Arizona AMS iodine-129 program

Persistent Link:
http://hdl.handle.net/10150/290106
Title:
Development and applications of the NSF-Arizona AMS iodine-129 program
Author:
Biddulph, Dana L.
Issue Date:
2004
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The use of the long-lived radioisotope ¹²⁹I as an environmental tracer is increasing in popularity. An application of nuclear physics that is known as Accelerator Mass Spectrometry (AMS) can be used to measure ¹²⁹I in various sample matrices at a level of a few parts in 10¹⁴. The system employs a 3 MV electrostatic accelerator as one component of a mass spectrometer. As accelerated ions have kinetic energies of several million electron volts, nuclear physics techniques can be used to remove interferences from the ions of interest. Techniques for the extraction of iodine from a variety of samples including calcium carbonate, seawater, plants and animals have been developed. Results from many of these samples have been submitted as part of a laboratory inter-comparison exercise. As an application of oceanographic tracer studies, ¹²⁹I has been measured in a banded coral that lived in the southern Pacific Ocean for more than 50 years. The results of this study confirm that iodine is fixed within the coral skeleton upon deposition, and that these measurements record the history of iodine levels in the surface waters of the ocean over time. ¹²⁹I may also be a good indicator of past changes in the galactic cosmic ray flux and the magnitude and orientation of Earth's magnetic field. A 40 kyr iodine record extracted from a stalagmite in the Bahama Islands shows varying ¹²⁹I concentrations that may be linked to such changes. This record is in agreement with other published records of ¹⁰Be and ³⁶Cl. As ¹²⁹I has a much longer half-life than other cosmogenically produced isotopes, there is a potential for extending these records much further back in time.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Geophysics.; Physics, General.; Environmental Sciences.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Physics
Degree Grantor:
University of Arizona
Advisor:
Donahue, Douglas J.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleDevelopment and applications of the NSF-Arizona AMS iodine-129 programen_US
dc.creatorBiddulph, Dana L.en_US
dc.contributor.authorBiddulph, Dana L.en_US
dc.date.issued2004en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe use of the long-lived radioisotope ¹²⁹I as an environmental tracer is increasing in popularity. An application of nuclear physics that is known as Accelerator Mass Spectrometry (AMS) can be used to measure ¹²⁹I in various sample matrices at a level of a few parts in 10¹⁴. The system employs a 3 MV electrostatic accelerator as one component of a mass spectrometer. As accelerated ions have kinetic energies of several million electron volts, nuclear physics techniques can be used to remove interferences from the ions of interest. Techniques for the extraction of iodine from a variety of samples including calcium carbonate, seawater, plants and animals have been developed. Results from many of these samples have been submitted as part of a laboratory inter-comparison exercise. As an application of oceanographic tracer studies, ¹²⁹I has been measured in a banded coral that lived in the southern Pacific Ocean for more than 50 years. The results of this study confirm that iodine is fixed within the coral skeleton upon deposition, and that these measurements record the history of iodine levels in the surface waters of the ocean over time. ¹²⁹I may also be a good indicator of past changes in the galactic cosmic ray flux and the magnitude and orientation of Earth's magnetic field. A 40 kyr iodine record extracted from a stalagmite in the Bahama Islands shows varying ¹²⁹I concentrations that may be linked to such changes. This record is in agreement with other published records of ¹⁰Be and ³⁶Cl. As ¹²⁹I has a much longer half-life than other cosmogenically produced isotopes, there is a potential for extending these records much further back in time.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectGeophysics.en_US
dc.subjectPhysics, General.en_US
dc.subjectEnvironmental Sciences.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorDonahue, Douglas J.en_US
dc.identifier.proquest3145045en_US
dc.identifier.bibrecord.b47209975en_US
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