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T H Is D Is S E R Ta Tio N Has Been G1—5072 M Ic R O F Ilm E D E X Actly As This dissertation has been G1—5072 microfilmed exactly as received BOWMAN, Jr., George Br'ice, 1932- DECON TAMIN ATION OF SOME SE EEC TED BABE EARTH ISOTOPES AND T1IE GAMMA RADIATIONS OF HAFNIUM-172 AND -173. The Ohio State University, Ph.D., 1961 Physics, nuclear University Microfilms, Inc., Ann Arbor, Michigan IECQNTAMINATICffi OF SOME SELECTED RARE EARTH ISOTOPES AMD THE GAMMA RADIATIONS OP HAIOTUM-172 AND -175 DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By George Price Bovaan, Jr., B. S., A. K. Capt&in, United States Air Force The Ohio State University 1961 Approved hy J / / A .......* / -it. i ..-'.v Adviser Department of Chemistry ■ ■ IV. .1 1 . ^ ^ .i.i A dviser Department of Physics ACXNCWIEDGMEHT The author wishes to express his appreciation to Professor M. H. Kurbatov and Professor J. D. Kurbatov for their guidance in this research, to Hr. H. J. Sathoff and Mr. P. J. Bradley for their assistance in collecting- the data, and to the United States Air Force for providing the opportunity for him to pursue this course of study. ii CONTENTS CHAPTER Page I CHEMICAL PURIFICATION OF SEIECTED RARE EARTH ISOTOPES . 1 Description of Cation-Exchange Columns ................................. 3 General Chemical Procedure for Decontamination of the Enriched Isotope Samples .................................................... 8 Chemical Procedure Flow Sheet .................................................... 11 P u rific a tio n of Neodymium-144 S a m p l e ................................. 12 P u rific a tio n of I>yspro3iui[h*156 S a m p l e ........................................14 Purification of Erbiunwl62 Sample ....... 18 P u rific a tio n of Neodymiun*-146 S a m p l e ........................................21 Determinate on of Samarium Decontamination Factors . 23 I I CARRIER-FREE SEPARATION OF HAFNIUM AND LUT3TIUM FROM YTTERBIUM OXIDE CYCLOTRON TARGETS ........................................ 33 Carrier-Free Hafnium Procedure Flow Diagram .... 41 Carrier-Free Lutetium Procedure Flow Diagram .... 42 I I I INSTRUMENTATION AND DATA A N A L Y SIS......................................................43 Counting Equipm ent .............................................................................. 43 Determination of the True Coincidence Spectrum . 45 IV GAMMA RAYS EMITTED IN THE DECAY OF HAFNIUM-172 AND THEIR COINCIDENCES .....................................................49 Method of Mounting Hafnium-172 Sample for Counting . 54 Measurement of Hafnium-172 Gamma Singles Spectrum with Continuous Lutetium-172 R em oval ........................................57 Determination of the Relative Abundances of Gamma Rays. 58 iii CONTENTS (Continued) CHAPTER Page IV (Continued) Measurement of Hafnium-172 Coincidence Spectra and Corrections for Lutetiun^l72 Daughter Groirth .... 65 The Energy Level Schem e ........................................................................89 Estimation of the Quantity of Hafnium-175 Present . 100 Assignments of Relative Gamma Ray Abundances .... 104 Estimated Corrections for Internal Conversion . 109 Estimated Log-ft Values for Electron Capture .... 115 V GAMMA RAYS EMITTED IN THE DECAY OF HAFNIUM-173 .... 118 The H alf-L ife of H a fn iu m -1 7 3 ......................................................... 120 Gamma-Gamma Coincidences Observed in the Decay of Hafnium-173 ............................................................................ 125 VI SUMMARY AMD DISCUSSION OF RESULTS ...................................................126 Chemical Purification of Rare Earth Samples .... 126 Measurement of Gamma Radiation in the Decay of Hafhium-172 ................................................................ 126 Energy Levels in Lutetium-172 from the Decay of Hafnium-172 ............................................................................ 128 The Decay of Hafnium-1 7 5 ............................................................... 133 BIBLIOGRAPHY................................................................................................................... 134 AUTOBIOGRAPHY.............................................................................................................136 i v ILHJ5TRATIQN5 Figure Title Page 1 D e ta il of Heated Cation-Exchange Column ...................................... 4 2 Heated Cation-Exchange Column A p p a ra tu s ...................................... 5 3 S ep aratio n of Neodymium Samples from Samarium and Other Hare E arths.............................. .................................................13 4 S ep aratio n of Dysprosium Samples from Holmium, Terbium, and Other Rare Earths .......... 15 5 Separation of Erbium Samples from Thulium, Holmium, and O ther Hare E a r t h s ..................................................................19 6 Studies of Samarium Decontamination Achieved in the Erbium, Dysprosium, and Neodymium Procedures Using Radioactive Samarium-153 T ra c e r .....................................................................................24 7 Shape of an Elution Band from Heated Cation-Exchange Column Run Number 4 7 .....................................................................................>2 8 Separation of Lutetium, Ytterbium, and Thulium Samples in 10 Milligram Q u a n titie s .....................................................39 9 Sketch of Apparatus Used for Mounting the Hafnium-172 Sample Permitting Chemical Removal of Lutetium Either During or Between Counting Measurements ..............................................56 10 Gamma Spectrum in the Decay of Hafnium-172 ...................................... 59 11 Example of the Subtraction of a Lutetium Coincidence Spectrum from an Observed Hafnium Coincidence Spectrum to Obtain the True Hafnium Spectrum Coincident with 396—418 kev R a d i a t i o n ..................................................................................................69 12 Gamma Spectrum Coincident with the Lutetium K X-ray in the Decay of Hafnium-172 .................................................... 72 13 Gamma Spectrum Coincident with 00 kev (79-87) Radiation in the Decay of Hafnium -172 ..............................................73 14 Gamma Spectrum Coincident with 88 kev (88-96) Radiation in the Decay of Hafnium -172 ..............................................74 15 Gamma Spectrum Coincident with 103 kev (96-106) Radiation in the Decay of Hafnium -172 ..............................................75 v ILLUSTRATIONS (Continued) Figure Title Page 16 Gamma Spectrum Coincident with 115 kev (109-115) Radiation in the Decay of Hafnium-1 7 2 .............................................. 76 17 Gamma Spectrum Coincident with 124 kev (122-130) Radiation in the Decay of Hafnium -172 .............................................. 77 18 Gamma Spectrum Coincident with 153 kev (148-158) Radiation in the Decay of H afnium -172 .............................................. 78 19 Gamma Spectrum Coincident with 188 kev (180-198) Radiation in the Decay of Hafniura-172 .............................................. 79 20 Gamma Spectrum Coincident with 202-225 kev Radiation in the Decay of Hafnium-172 . 80 21 Gamma Spectrum Coincident with 235-267 kev Radiation in the Decay of Hafnium -172 .............................................. 81 22 Gamma Spectrum Coincident with 275-303 kev Radiation in the Decay of Hafnium -172 .............................................. 82 23 Gamma Spectrum Coincident with 308-327 kev Radiation in the Decay of Hafnium -172 .............................................. 83 24 Gamma Spectrum Coincident with 345 kev (356-353) Radiation in the Decay of Hafnium -172 .............................................. 84 25 Gamma Spectrum Coincident with 557-372 kev Radiation in the Decay of Hafnium -172 .............................................. 85 26 Gamma Spectrum Coincident with 372-391 kev Radiation in the Decay of Hafnium -172 .............................................. 86 27 Gamma Spectrum Coincident with 396-418 kev Radiation in the Decay of Hafnium -172 .............................................. 87 28 Partial Level Schemes in Lutetium-172. Part 1 .... 90 29 Partial Level Schemes in Lutetium-172. Part 2 .... 95 30 Energy Levels in Lutetium-172 from the Decay of Hafnium-172. 114 31 Decay of the 124 kev Photopeak of Hafnium-173 .............122 vi TABIES Number Titlm Page 1 Samarium-153 Activities in Sandies from Run Numbers 47 and 4 8 ............................................................................................................ 28 2 A c tiv itie s Observed in S elected Tubes of Run Number 47 . 31 3 Photopeak-to—Total Detection Efficiency Ratio for Various Gamma Ray Standards ............................................................ 63 4 Resolved Hafnium-172 R elative Gemma Ray Abundances . 64 5 Observed Hafnium-172 Gamma-Gamma Coincidences ................................ 88 6 Assigned and Resolved Hafnium-172 Relative Gamma Ray A b u n d a n c e s ................................................................................. 106 7 Number of Gamma T ran sitio n s To and Prom Each Level . U 0 8 Estimates of the Total Number of T ransitions .............................. 112 9 Estimated Amount of E-Electron Capture to Various Siergy Levels ........................................................112 10 Estimated Log-ft Values for Electron Capture in Hafhiuiiwl72 ..............................................................................................117
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