Rob Hewitt, Robyn Reist, Jason SadowskiEngineering 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 238U spectrum and decay chain• How to determine abundance of 238U

• Apparatus• Simplified calculations• Software

• Simulated demonstration• Wrap-up/future goals

Overview of ProjectUranium ore analysis system for ArevaCurrently only measure total radiationSystem is needed to determine percentage of

uranium in an ore sampleTo be used by technicians on-site or in the labDefined project according to given constraints:

Determine abundance of 238U in a sample using the most accurate, user friendly, and cost

effective system.

Uranium Decay and Spectrum 101Radioactive isotopes decay into other elements by

alpha and beta decay and give off gamma ray photonsLooking for 238U

Separate out 235U or create 239Pu (239U -> 239Np -> 239Pu)Need to look further down chainMeasure the gamma energy given off by these

isotopes

238U Decay Chain and Spectrum

-100

0

100

200

300

400

500

600

700

50 150 250 350 450 550 650

295 keV

352 keV

Energy, keV

609 keV

Stable

Junk

What to expect from 1g Uranium?Described by 14 equations

4.468x109 Yrs

24 days

234Th

238U

• Each decay has probability of gamma ray emission

What to expect from 1g Uranium?

214Bi (609 keV)5.8x103 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?

gsgphotons

sphotons724.1

/108.5

/10103

3

Correct for detector efficiency and sample geometryExample (using one peak):

We know 1g natural U emits 5.8x103 photons/s at 609 keVWe have a 20 g sample and measure 10x103 photons/s in the 609 keV

line

This peak indicates 8.62% Uranium

Software

Graphical User Interface – QT

Program Demonstration

Wrap-UpGoals:

AccurateCost-effectiveUser friendly (automated and portable)

Next step: detailed documentation

SummaryProject overview238U introduction/Detecting gamma raysDetector types and testing apparatusCalculating percentage 238USoftwareDemonstrationMet goals, now documenting

Questions?

Choosing a DetectorNaI LaBr HPGe

Price ~$10k ~$30k ~$30-100k

Resolution at 662 keV 9.07% 3.42% 0.29%

Stabilization Time 1 hour 30 seconds 24 hours cooling