Transcript Final Presentation

Uranium Ore Analysis
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)
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 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 238U 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 238U
 Separate out 235U or create 239Pu (239U -> 239Np -> 239Pu)
 Need to look further down chain
 Measure the gamma energy given off by these
isotopes
238U
234Th
238U
234Pa
Decay Chain and Spectrum
234U
700
230Th
600
226Ra
222Rn
500
295 keV
218Po
214Pb
214Bi
609 keV
352 keV
400
300
200
214Po
100
Junk
210Pb
210Bi
0
210Po
-100
206Pb
Stable
50
150
250
350
Energy, keV
450
550
650
What to expect from 1g Uranium?
 Described by 14 equations
• Each decay has probability of
gamma ray emission
238U
4.468x109 Yrs
234Th
24 days
What to expect from 1g Uranium?
214Bi
(609 keV)
5.8x103 photons/s
Recommendation: LaBr Detector
Testing Apparatus
Built for Specific
Detector
Fixed Geometry
Adjustable
Ruler
Bulky
Specific
Rock Sizes
Sealed Sample
Holders
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 5.8x103 photons/s at 609 keV
 We have a 20 g sample and measure 10x103 photons/s in the 609 keV
line
10103 photons/ s
 1.724g
3
5.8 10 photons/ g  s
 This peak indicates 8.62% Uranium
Calibrate
Software
Analyze
Load Spectrum
Load Known
Spectrum
Enter Mass,
Geometry
Find Detector
Efficiency
Load Calibration File
Find Energy
Locations
Calculate Activity
Graphical User Interface – QT
Program Demonstration
Wrap-Up
 Goals:
Accurate
Cost-effective
User friendly (automated and portable)
 Next step: detailed documentation
Summary
 Project overview
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238U
introduction/Detecting gamma rays
Detector types and testing apparatus
Calculating percentage 238U
Software
Demonstration
Met goals, now documenting
Questions?
Choosing a Detector
NaI
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