1. Section 19.2 Application of Radioactivity To learn about some uses of radioactivity in our lives Objectives

2. Section 19.2 Application of Radioactivity Some Uses Of Radioactivity Food Sterilization Medical Applications and Radiotracers Smoke detectors Radiocarbon Dating (Energy Production) (Weapons)

3. Section 19.2 Application of Radioactivity Food Sterilization Gamma irradiation of foods often from 60 Co source Spices, herbs and dehydrated vegetables. Also pork and poultry FDA approved

4. Section 19.2 Application of Radioactivity Medical Applications of Radioactivity Radioactive nuclides can be introduced into laboratory reactions or organisms and traced for diagnostic purposes. Radiotracers

5. Section 19.2 Application of Radioactivity Medical Applications of Radioactivity - Scanners Medical Scanners utilize many types of radiations XX-Rays – Bone structures opaque to rays XX-ray computed tomography (CT Scan – X-rays) XMagnetic Resonance Imaging (MRI – Nuclear magnetism) XUltrasound (high frequency sound waves) Positron Emission Tomography (PET Scan) Positron emitting tracer into body, concentrates in organ of interest Positrons annihilate with electron giving off pairs of gamma rays Detector maps pair to show image of organ

6. Section 19.2 Application of Radioactivity Smoke Detectors Americium-241 emits alpha particles and ionizes air in a space in the detector Ions allow a current to flow Smoke absorbs alpha particles, interferes with ion formation and electric current. An alarm sounds

7. Section 19.2 Application of Radioactivity Dating by Radioactivity Originated in 1940s by Willard Libby –Based on the radioactivity of carbon-14 Radiocarbon dating Used to date wood and artifacts up to about 50,000 years old Radiocarbon dating activity