Lecture Notes 9-28 - prof Paul Bureau PDF

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prof Paul Bureau...

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AH3275 - 9/28/2017 Midterm 10/05 – open note, open book, open laptop!!! Multiple choice, true/false, short answer

Radiation Immediate concern is whether there’s radiation on site – use monitoring equipment Radioactive=unstable It has too much energy & wants to release radioactive atoms to become stable Released as electromagnetic energy or particulates energy Can take days to billions of years to reach ground state Biological tissue in exposure can absorb the radioactive energy This is bad because it can cause cancer, genetic mutations & damage in DNA Power lines, TV, cell phones, microwaves, infrared devices, & light bulbs all have radiation but are at such low frequencies that they don’t have the potential to harm DNA Radioactive materials have very high energy and frequency- this is our main concern in EHS Once inside our body, still releases high energy but in a small space (potentially in organs) - high density Different types of radiation: alpha, gamma, beta, x 

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Alpha- Positively charged, comes from heaviest radioactive elements (like uranium & radium), heavier than air – quickly fall to surfaces, skin exposure is usually fine, inhalation is the biggest issue because of target organs Beta- smaller, negatively charged, lighter – stay in the atmosphere for longer, less damaging because their ionizations are more spaced out (like tritium & hydrogen-3) Gamma- weightless photons, high intensity, big hazard throughout the entire body X-rays- Similar to gamma but lower in energy & less penetrating

Health effects can be either: Acute- high concentration, high intensity, short period of time Chronic- continuous radiation exposure, less intensity, long period of time Maximum Exposure Standards: 5 Rem/year (or 5,000 millirem/year) 3 rem/quarter (every 3 months) 500 millirem during pregnancy Ex.) In a space with 100 mrem/hour radiation, you could spend 10 hours in a quarter ( *10 hrs = 1 Rem)

Common Radioactive Elements: 

Radon – gas emits alpha particle

Precautionary Measures:   

Reduce exposure time Increase distance from source [Lead] shielding apron – usually over the reproductive organs bc most vulnerable to radiation Half value layer – thickness of material that will reduce the radiation level in half...