Radiation Shielding A 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 Results Lab #1 Verify 1/r 2 law experimentally using Cesium source. Determine background radiation (0.2 µSv).

Lab Results Lab #2 Experimentally calculate Gamma Attenuation of Plastic, Lead, Aluminum, and Copper.

Material Selection (CES)

Proposed Design Three Assumptions: –Source emits 1mSv/s. –Density of lead is 11,340 kg/m 3. –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 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.