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Information about Tritium_Presentation_MASTER_backup

Published on April 21, 2008

Author: wizaplite1


Slide 1: Preston Gudmunson, Sara Rowley, & Travis Andelin Tritium Scientific Background : Scientific Background Outline : Outline Introduction to tritium Scientific background Why we care Case studies How tritium data is gathered at BYU Collection Enrichment Analysis Scientific Background : Scientific Background Image from: Scientific Background : Scientific Background What is Tritium? Tritium half-life: 12.43 years Slide 6: Natural Tritium Formation How is Tritium Formed? Slide 7: Image from: How is Tritium Formed? Artificial Tritium Formation n + 6Li  3H + 4He n + 7Li  3H + 4He + n Information from: Scientific Background : Scientific Background Tritium Concentrations in Precipitation for Salt Lake City, Utah during 1962 and 1963 (Data from Stewart and Hoffman, 1966) Scientific Background : Scientific Background Where is tritium found? Atmosphere Water Scientific Background : Scientific Background Why Do We Care? Uses of Tritium Watches Nuclear fusion Power plants Bombs Hollywood pizzazz Groundwater testing Scientific Background : Scientific Background Conclusion Characteristics Formation Locations Bomb history Uses of Tritium Slide 12: Outline The groundwater problem Case studies Whom groundwater effects How tritium can help Why Use Tritium? : Why Use Tritium? Slide 14: Reasons groundwater is needed Low precipitation/semi-arid regions Contaminated surface water Dangers Run out of water Salt water intrusion Geologic hazards associated with over-pumping Only mine “fossil water” in emergencies Case Study : Case Study Africa: arid climate & contamination Deep boreholes run dry/turn saline Flow models show: Contaminant/salt migration Recharge rates Case Study : Case Study China: drought & over pumping 1-2 m below surface in 1960’s Now = 25-27 m below surface Dropping 0.72 m/year Recharging 0.113 m/year Taihang Mountains Slide 17: Utah Utah owns all water rights Must prove source of “new” aquifers 14C gives “age” (residence time) (Mayo, A., Morris, T., et al. 2003, p. 14) Slide 18: Conclusion Help communities plan better Find viable water sources Settle legal disputes Save lives Case Study : Case Study Conclusion Help communities plan better Find viable water sources Gathering Tritium Data : Gathering Tritium Data Gathering Tritium Data : Gathering Tritium Data Water Sample Collection Common Scenarios BYU Research Paying customers Information about sample is logged to computer Gathering Tritium Data : Gathering Tritium Data Distillation 250mL of sample is distilled Removes minerals and impurities Water is boiled and cooled, collected in a flask Gathering Tritium Data : Gathering Tritium Data Enrichment Gathering Tritium Data : Gathering Tritium Data Enrichment Tritium levels are dropping (short half life) Electrolysis used to enrich the sample Increases the tritium concentration Gathering Tritium Data : Gathering Tritium Data Enrichment Electrolysis Electrolysis separates water into H2 and O2 Leaves behind Tritium and Deuterium, enriching sample Slow process; sodium peroxide used New tritium concentration is 15-25 times the original concentration Gathering Tritium Data : Gathering Tritium Data Vacuum Distillation Gathering Tritium Data : Gathering Tritium Data Vacuum distillation Water is distilled again Removes sodium peroxide from enriched sample Done in a vacuum to avoid fractionation Gathering Tritium Data : Gathering Tritium Data Liquid Scintillation Counting Scintillant added to the sample Counted using the Liquid Scintillation Counter When tritium decays, it releases energy Scintillant causes energy to be emitted as a photon LSC counts number of light emissions Determines amount of tritium Gathering Tritium Data : Gathering Tritium Data Conclusion High demand – Lots of application in geology Precision and detail are important Uses physics and chemistry to determine otherwise obscure data Slide 30: Thank you Slide 31: Faure, G. (1986). Principles of isotope geology (2nd ed.). New York, NY: John Wiley & Sons. Stewart, G. L., & Hoffman, C. M. (1966). Tritium rainout over the united states in 1962 and 1963. Geological Survey Circular 520, (520), 1-11. References

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