Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1971 Simultaneous Determination of Gold, Mercury, Silver, Tellurium and Uranium by Instrumental Neutron and Photon Activation Analysis. Frank Thomas Campbell II Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Campbell, Frank Thomas II, "Simultaneous Determination of Gold, Mercury, Silver, Tellurium and Uranium by Instrumental Neutron and Photon Activation Analysis." (1971). LSU Historical Dissertations and Theses. 1968. https://digitalcommons.lsu.edu/gradschool_disstheses/1968 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 71-2 9 ,31*9 CAMPBELL II, Frank Thomas, 1939- SIMULTANEOUS DETERMINATION OF GOLD, MERCURY, SILVER, TELLURIUM AND URANIUM BY INSTRUMENTAL NEUTRON AND PHOTON ACTIVATION ANALYSIS. The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1971 Chemistry, analytical University Microfilms, A XEROX Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED SIMULTANEOUS DETERMINATION OF GOLD, MERCURY, SILVER, TELLURIUM AND URANIUM BY INSTRUMENTAL NEUTRON AND PHOTON ACTIVATION ANALYSIS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Chemistry Frank Thomas Campbell II B.S., Fresno State College, 1963 M.S., San Diego State College, 1967 to my parents and my sister who helped to make me the way 1 am to my friends who believed in me even when I did not and especially to Linda, my unwitting inspiration 11.... there are no easy victories...." John W. Gardner Acknowledgment The author wishes to acknowledge the contributions to his betterment made by Professors James W. Robinson, Norman S. Bhacca, and Edgar L. Steele. Special thanks go to Dr. Edward F. Zganjar, Dr. David A. Copeland, Dr. J. Tracy Broussard, Mrs. Patricia A. Kelly and Dr. Edgar L. Steele for the assistance, of a personal nature, which they so graciously conferred to the author. This grateful acknowledgment is the only means of compensation which the author is able to offer to them for their most generous efforts on his behalf. The author wishes to express a general thanks to all of those persons who have contributed directly, or indirectly, to his work and to his life. He also wishes to thank those persons who have not been a hindrance. The author gratefully acknowledges the financial assistance in preparation of this dissertation which was provided by the Charles E. Coates Memorial Fund of the Louisiana State University Foundation. Most of all, and far above any other, the author wishes to express his gratitude to Professor Edgar L. Steele who has been, not only a research director, but also a personal friend and an example as well. He took a two-time loser to the pot of gold. ii Table of Contents Page Acknowledgment................................................. ii List of Tables................................................. iv List of Figures ............................................... v Abstract......................................................... vii Chapter I. Introduction................................... 1 Chapter II. Review of the Literature...................... 4 Chapter III. Experimental..................................... 17 Chapter IV. Experimental Procedures, Data and Results . 24 Chapter V. Discussion and Conclusions...................... 73 Appendix 1 ...................................................... 85 Appendix I I ....................................................91 References.....................................................107 Vita........................................................... 115 iii List of Tables Table Page 1. Energy Resolution of Gamma Ray Spectrometer ......... 22 2. Experimentally Determined Values of Relative Efficiency of the Full-Energy Peak 22 3. Nuclear Data for Selected Isotopes...................... 48 4. Potential Sources of Interference .................... 49 5. Data for Go l d ........................................... 58 6. Data for Mercury......................................... 61 7. Data for Si l v e r ......................................... 64 8. Data for Tellurium....................................... 67 9. Data for Uranium......................................... 70 10. Calculated Accuracies and Sensitivities .............. 74 11. Data for Mercury......................................... 98 12. Data for Si l v e r ........................................ 101 13. Data for Tellurium...................................... 104 iv List of Figures Figure Page 1. Aluminum Disk for Linac Irradiation. ..............19 2. Gamma Ray Spectrum 6f Gold 5 Days After Irradiation with Photons .............................................. 27 3. Gamma Ray Spectrum of Mercury 5 Days After Irradiation with Photons .............................................. 28 4. Gamma Ray Spectrum of Silver 5 Days After Irradiation with Photons .............................................. 29 5. Gamma Ray Spectrum of Tellurium 5 Days After Irradiation with Photons .............................................. 30 6. Gamma Ray Spectrum of Uranium 5 Days After Irradiation with Photons .............................................. 31 7. Gamma Ray Spectrum of Gold 10 Days After Irradiation with Neutrons.............................................. 32 8. Gamma Ray Spectrum of Mercury 10 Days After Irradiation with Neutrons.............................................. 33 9. Gamma Ray Spectrum of Silver 10 Days After Irradiation with Neutrons.............................................. 34 10. Gamma Ray Spectrum of Tellurium 10 Days After Irradia­ tion with Neutrons ........................................ 35 11. Gamma Ray Spectrum of Uranium 10 Days After Irradia­ tion with Neutrons...................................... 3 6 12. Calibration Curve - Gold LINAC ........................... 37 13. Calibration Curve - Mercury LINAC......................... 38 v Figure Page 14. Calibration Curve - Silver LINAC ........................ 39 15. Calibration Curve - Tellurium LINAC....................... 40 16. Calibration Curve - Uranium LINAC..........................41 17. Calibration Curve - Gold Reactor ..........................42 18. Calibration Curve - Mercury Reactor....................... 43 19. Calibration Curve - Silver Reactor ...................... 44 20. Calibration Curve - Tellurium Reactor..................... 45 21. Calibration Curve - Uranium Reactor....................... 46 140 140 22. Growth Decay Curve for Ba- La Couple................ 81 23. Photofission Spectrum of Uranium 2 Days after Irra­ diation.....................................................82 24. Photofission Spectrum of Thorium 2 Days after Irra­ diation..................................................... 83 25. Gamma Ray Spectrum of Mercury 2 Days after Irradiation with Photons .............................................. 93 26. Calibration Curve - Mercury (197m) LINAC ................ 94 27. Calibration Curve - Mercury (203) LINAC (Later Count). 95 28. Calibration Curve - Silver LINAC (Later Count) ........... 96 29. Calibration Curve - Tellurium LINAC (Later Count). 97 vi Abstract A rapid, inexpensive method for the determination of gold, mercury, silver, tellurium and uranium was developed. The method utilized non-destructive activation analysis by means of gamma ray spectrometry. Both neutrons and photons were used as sources of activation. Irradiation of a stable nucleus with neutrons results in the formation of an unstable nucleus of mass number one greater than the target nucleus while bombardment with photons causes a loss of one mass number. The different radio­ isotopes yield different gamma ray spectra thus enhancing the likelihood of obtaining an interference-free peak. Computer reduction of the data reduces the time required for analysis to two hours per sample, only slightly more than the counting time. Minimal laboratory skill is required to obtain sensi­ tivities as follows: Au 3.4 PPM Hg 74.6 PPM Ag 198.1 PPM Te 120.0 PPM U 16.6 PPM The precision obtained was 20% or better. An exhaustive survey of potential interferences was conducted and means of elimination are discussed. Several modifi­ cations and extensions of the method are included indicating its flexibility and response to the particular needs of the analyst. vii Chapter I Introduction A rapid, inexpensive method for the determination of gold, mercury, silver, tellurium and uranium in soil and rocks was developed. The purpose of this research was to demonstrate the feasibility of determining these elements by a fully instrumental, nuclear activation analysis procedure. Eliminating chemical separations minimizes sample handling and reduces the requirements of time and technical skill on the part of the analyst. Thus, rapid analysis of multitudinous samples becomes possible. Activation analysis is based upon the production of unstable nuclei from stable nuclei and the measurement of radi­ ations emitted when these nuclei subsequently decay to stable states.