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Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2018 Correlation between delay time and measured concentration and concentration uncertainty by neutron activation analysis James Thomas Seman Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Mining Engineering Commons, Nuclear Commons, and the Nuclear Engineering Commons Department: Mining Engineering Recommended Citation Seman, James Thomas, "Correlation between delay time and measured concentration and concentration uncertainty by neutron activation analysis" (2018). Doctoral Dissertations. 2729. https://scholarsmine.mst.edu/doctoral_dissertations/2729 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. ii CORRELATION BETWEEN DELAY TIME AND MEASURED CONCENTRATION AND CONCENTRATION UNCERTAINTY BY NEUTRON ACTIVATION ANALYSIS by JAMES THOMAS SEMAN A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in EXPLOSIVES ENGINEERING 2018 Approved Dr. Catherine Johnson, Advisor Dr. Carlos H. Castano Giraldo Dr. Paul Worsey Dr. Ayodeji B. Alajo Dr. Gillian Worsey iii Ó 2018 James Thomas Seman All Rights Reserved iii ABSTRACT For the last several decades, it has been apparent that new methods of identifying explosives can help investigators trace their origins. One way to identify an explosive is through the use of taggants: materials added to a product that encodes information about the product such as when it was manufactured. This research investigates the survivability of a new identification taggant called the Nuclear Barcode that overcomes some of the downfalls that have been identified in prior taggants. The Nuclear Barcode encodes information as a unique combination of concentrations of rare earths (Ho, Eu, Sm, Lu, and Dy) and precious metals (Ir, Rh, and Re) that is then identified using Neutron Activation Analysis (NAA). The concept of “survivability” was tested through a series of experiments on aqueous solutions and post- blast residues containing three rare earths (Ho, Eu, and Sm). The tests have shown that the three candidate taggant elements can be identified by NAA in an aqueous solution at concentrations as low as 100 parts per billion (ppb) with uncertainties in the concentration measurement as low as 5 ppb. These elements can be identified in post-blast residue produced by a detonating explosive at higher concentrations of 1,000 ppb. Being able to identify the taggant elements at these concentrations is critical for the practical implementation of the Nuclear Barcode, which requires uncertainties below 50 ppb. Five parameters were identified as contributing to the uncertainty and the effect of the delay time was investigated. After a period of 2.5 half-lives, the uncertainty in the concentration was found to be higher than the uncertainty immediately afterward, suggesting that samples be measured as soon as possible and eliminating some candidates. iv ACKNOWLEDGMENTS I would like to thank my committee for their teaching, advice, and support in carrying out this research. I’d like to thank my advisor Dr. Catherine Johnson for all of her efforts in helping move this research forward as well as for putting up with my terrible first drafts. I’d also like to thank Dr. Carlos Castaño for his insights into the subtler details of neutron activation analysis that often eluded my grasp. Dr. Paul Worsey has probably forgotten five times the things our conversations have taught me over the course of this degree. I would like to thank Dr. Ayodeji Alajo for teaching me more about nuclear engineering than I ever expected to learn while pursuing this research. Finally, I’d like to thank Dr. Gillian Worsey for the broader perspective that she brought to the research. This research would not have been possible without the aid of the staff at the Missouri S&T Reactor, and especially Craig Reisner and Anthony Alchin. I greatly appreciate their support that allowed me to use the full capabilities of the MSTR. The post- blast tests that were critical to this research could not have been carried out without the support of Jeff Heniff, and my fellow graduate students Jay Schafler, Barbara Rutter, Martin Langenderfer, Jacob Brinkman, and Kelly Williams. Many thanks also to Phil Mulligan for his assistance in structuring much of the writing you see here. Finally, I would like to thank my family and friends for helping to keep me sane during the busiest times while carrying out this research. I would have been lost without them. v TABLE OF CONTENTS Page ABSTRACT .................................................................................................................. iii ACKNOWLEDGMENTS ..............................................................................................iv LIST OF ILLUSTRATIONS ..........................................................................................xi LIST OF TABLES ...................................................................................................... xiii SECTION 1. INTRODUCTION ................................................................................................... 1 1.1. RESEARCH MOTIVATION FOR AN IDENTIFICATION TAGGANT......... 2 1.2. THE NUCLEAR BARCODE: A NOVEL IDENTIFICATION TAGGANT .... 4 1.3. RESEARCH OBJECTIVES ............................................................................. 7 1.4. CONTRIBUTION TO SCIENCE..................................................................... 9 1.5. ORGANIZATION OF THIS DOCUMENT ................................................... 10 2. LITERATURE REVIEW ...................................................................................... 12 2.1. TAGGANTS LITERATURE REVIEW ......................................................... 12 2.1.1. Overview ............................................................................................. 13 2.1.2. Historic Events and Their Relation to Taggant Development................ 15 Early explosives regulations (1917-1970). ................................ 16 Initial taggants (1971-1980). .................................................... 20 Updated taggants (1981-1998). ................................................ 26 Modern taggants (2000- present). ............................................. 33 2.1.3. Summary of Taggants Literature. ......................................................... 36 vi 2.2. NEUTRON ACTIVATION ANALYSIS LITERATURE REVIEW ............... 38 2.2.1. Overview of NAA. ............................................................................... 39 2.2.2. Mathematical Analysis. ........................................................................ 41 2.2.3. Uses of NAA. ...................................................................................... 45 2.2.4. Summary of NAA. ............................................................................... 46 2.3. EXPLOSIVES LITERATURE REVIEW ....................................................... 47 2.3.1. Explosives Chemistry........................................................................... 47 2.3.2. Explosive Characterization. .................................................................. 48 2.3.3. Explosive Performance. ....................................................................... 50 2.3.4. Summary of Explosives. ...................................................................... 51 3. NUCLEAR BARCODE CONCEPT ...................................................................... 52 3.1. NUCLEAR BARCODE CONCEPT DESCRIPTION..................................... 52 3.2. NUCLEAR BARCODE CONCEPT EVALUATION..................................... 56 4. RESEARCH METHODS ...................................................................................... 59 4.1. NEUTRON ACTIVATION ANALYSIS USING MISSOURI S&T REACTOR ................................................................................................... 59 4.2. SINGLE ELEMENT STANDARD SOLUTIONS. ......................................... 61 4.2.1. Determine if the Taggant Elements can be Detected and Quantified via NAA at the Desired Concentration. ................................................ 62 4.2.2. Determine if the Different Concentration Levels of the Taggant Elements can be Distinguished and Quantified via NAA ..................... 62 4.3. MULTI-ELEMENT STANDARD SOLUTIONS ........................................... 63 4.3.1. Determine if the Taggant Elements can be Detected and Quantified via NAA at the Desired Concentration ................................................. 63 4.3.2. Determine if the Different Concentration Levels of the Taggant Elements can be Distinguished and Quantified via NAA ..................... 63 vii 4.3.3. Determine the Distinguishability of the Taggant Elements from Background Signal, such as other Taggant Elements and Common Elements in the Environment such as Sodium, Potassium, Chlorine, etc. ....................................................................................... 64 4.4. SINGLE ELEMENT BINARY POST-BLAST .............................................. 65 4.4.1. Determine the Distinguishability of the Taggant Elements

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