Radiation Shielding A Practical Approach to an Engineering

Radiation Shielding A Practical Approach to an Engineering Physics Problem in Engineer 1 P 03.

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 m. Sv 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 1 m. Sv/s. – Density of lead is 11, 340 kg/m 3. – Price of lead is $1. 50/kg.

Proposed Design Three Unknowns – Thickness of lead. – Create C++ Program! – Volume of lead. – Price of lead. Why ? ? ? Solution ? ? ? – 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 5 cm. – Thickness of lead is 13. 7 cm. – 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 50 m. Sv/year of radiation is met.

Conclusion • Thank you for your attention. • At this time, we would invite questions from the audience.