Rob Hewitt, Robyn Reist, Jason Sadowski Engineering Physics College of Engineering Student Paper Presentation Competition March 26, 2009 Supervisors: Mike Bradley, Chary Rangacharyulu Client: Tyson Pederson (Areva) Uranium Ore Analysis

Outline Overview/definition of project Introduction to 238 U spectrum and decay chain How to determine abundance of 238 U Apparatus Simplified calculations Software Simulated demonstration Wrap-up/future goals

Overview of Project Uranium ore analysis system for Areva Currently only measure total radiation System is needed to determine percentage of uranium in an ore sample To be used by technicians on-site or in the lab Defined project according to given constraints: Determine abundance of 238 U in a sample using the most accurate, user friendly, and cost effective system.

Uranium Decay and Spectrum 101 Radioactive isotopes decay into other elements by alpha and beta decay and give off gamma ray photons Looking for 238 U Separate out 235 U or create 239 Pu ( 239 U -> 239 Np -> 239 Pu) Need to look further down chain Measure the gamma energy given off by these isotopes

238 U Decay Chain and Spectrum 238 U 234 Th 234 Pa 234 U 230 Th 226 Ra 222 Rn 218 Po 214 Pb 214 Bi 214 Po 210 Pb 210 Bi 210 Po 206 Pb 295 keV 352 keV Energy, keV 609 keV Stable Junk

What to expect from 1g Uranium? Described by 14 equations 4.468x10 9 Yrs 24 days 234 Th 238 U Each decay has probability of gamma ray emission

What to expect from 1g Uranium? 214 Bi (609 keV) 5.8x10 3 photons/s

Recommendation: LaBr Detector

Adjustable Ruler Fixed Geometry Sealed Sample Holders Built for Specific Detector Bulky Specific Rock Sizes Testing Apparatus

How do we convert a spectrum to useful information? Correct for detector efficiency and sample geometry Example (using one peak): We know 1g natural U emits 5.8x10 3 photons/s at 609 keV We have a 20 g sample and measure 10x10 3 photons/s in the 609 keV line This peak indicates 8.62% Uranium

Software Analyze Load Spectrum Enter Mass, Geometry Load Calibration FileCalculate Activity Calibrate Load Known Spectrum Find Detector Efficiency Find Energy Locations

Graphical User Interface – QT

Program Demonstration

Wrap-Up Goals:  Accurate  Cost-effective  User friendly (automated and portable) Next step: detailed documentation

Summary Project overview 238 U introduction/Detecting gamma rays Detector types and testing apparatus Calculating percentage 238 U Software Demonstration Met goals, now documenting

Questions?

Choosing a Detector NaILaBrHPGe Price~$10k~$30k~$30-100k Resolution at 662 keV9.07%3.42%0.29% Stabilization Time1 hour30 seconds24 hours cooling