Radiation Shielding A Practical Approach to an Engineering Physics Problem in Engineer 1P03.
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Transcript of Radiation Shielding A Practical Approach to an Engineering Physics Problem in Engineer 1P03.
Radiation ShieldingA Practical Approach to an Engineering
Physics Problem in Engineer 1P03.
Introduction• Geoff Gudgeon
• Tony Machado
• Aliraza Murji
• Evie Sararas
Outline• Problem & Constraints
• Background
• Lab Results
• Material Selection
• Proposed Design
• Recommendations
• Conclusion
Problem & Constraints• Design an object that will shield the gamma
rays given off by a radioactive source.
• Maximum radiation emitted after shield limited to 50 mSv per year.
• Design must be economically and practically feasible.
Background• Types of Radiation
Alpha (α)
Beta (β)
Gamma (γ)
Neutron
Background• Nuclear Decay
– Atoms with greater than 83 Protons are unstable and will break down (known as Radioactivity).
• Gamma Ray Absorption– Photoelectric Absorption– Compton Scattering– Pair Production
• Absorbing Powers of Materials– Gamma radiation is attenuated exponentially when passing
through a shielding material.
Lab ResultsLab #1• Verify 1/r2 law
experimentally using Cesium source.
• Determine background radiation (0.2 µSv).
A graph of radius against activity
0
2
4
6
8
10
12
14
16
0 10 20 30 40 50 60
Radius (mm)
Act
ivit
y N
(u
Sv)
Lab ResultsLab #2• Experimentally
calculate Gamma Attenuation of Plastic, Lead, Aluminum, and Copper.
Plastic 0.00697 mm-1
Aluminum 0.0115 mm-1
Copper 0.0386 mm-1
Lead 0.119 mm-1
Attenuation Coefficients
Material Selection (CES)
Proposed Design
Three Assumptions:– Source emits 1mSv/s.– Density of lead is
11,340 kg/m3. – Price of lead is $1.50/kg.
Proposed Design
Three Unknowns– Thickness of lead.– Volume of lead.– Price of lead.
Solution ???
– Create C++ Program!
Why ???– Allows us to vary
parameters to maximize design attenuation and minimize cost!
Proposed Design
• Final Design:– Distance from source to inner wall of lead is 5cm.– Thickness of lead is 13.7cm.– Amount of lead used would total 111.055 kg.– Total cost of lead would be $172.58
Recommendation
• Design can be easily altered using the C++ program to accommodate changes in input variables.
• If not used on bottom floor, a lead plate with equal thickness to radius of dome should be implemented to protect people below.
• Cover lead with plastic to prevent handling of toxic lead.
Conclusion
• Our design offers the best choice of material to provide highest attenuation.
• Low-cost due to small volume of design.
• By using a dome, our design becomes geometrically efficient by absorbing radiation evenly.
• Health and Safety regulation limiting 50mSv/year of radiation is met.
Conclusion
• Thank you for your attention.
• At this time, we would invite questions from the audience.