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Ionizing Radiation CHEM 605 Fall 2005

Ionizing Radiation CHEM 605 Fall 2005. Mary J. Handy Health Physicist, Laser Safety Officer Dept. of Radiological and Environmental Management. Overview. Radiation 101 Background Radiation Biological Effects of Radiation Radiation Safety Guidelines Use of Geiger counter

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Ionizing Radiation CHEM 605 Fall 2005

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  1. Ionizing RadiationCHEM 605Fall 2005 Mary J. Handy Health Physicist, Laser Safety Officer Dept. of Radiological and Environmental Management

  2. Overview • Radiation 101 • Background Radiation • Biological Effects of Radiation • Radiation Safety Guidelines • Use of Geiger counter • Campus Emergency Procedures • Contact Us

  3. Radiation 101: Definitions • Radioactivity • Spontaneous emission of particles and/or electromagnetic radiation from an unstable nucleus. • Ionizing Radiation • Radiation of sufficient energy to strip electrons from the orbit of an atom. • Contamination • Radioactive material in an unwanted location. • Half-Life • The time required for any given radioisotope to decrease to one-half it’s original quantity • After 10 half-lives, the radioactivity is 99.9% gone

  4. Radiation 101: Radiation Types • There are 4 main types of radioactive emissions, each of which has different shielding requirements • Alpha • Shielded by air, skin, paper • Beta • Shielded by skin, aluminum, wood, Plexiglas • Gamma/x-rays • Shielded by lead • Neutrons • Shielded by hydrogen-containing materials, water, paraffin

  5. Radiation 101: Exposure • There are two ways that an individual can be exposed to radiation • Internal exposure • By mouth, nose, eyes, skin absorption, or any open cut • Main concern with alpha and low energy beta • External exposure • Energy is passed through the body and/or absorbed by tissues • Main concern with high energy beta, gamma, and neutron radiation

  6. Radiation 101: Rules to Reduce Exposure • Time • Reduce time in areas containing radioactive materials. • Distance • Keep your distance from radioactive materials- exposure drops very quickly. • Shielding • Use proper shielding to reduce exposure if shielding is necessary. • Contamination Control • PPE • Surveys

  7. Background Radiation • Average Annual Background Radiation Exposure in the US is approximately 360 mrem

  8. Zone 1 (>4pCi/l) Zone 2 (2-4 pCi/l) Zone 3 (<2 pCi/l) Radon (198 mrem) Average Annual Background Radiation Exposure in the US (360 mrem)

  9. Internal Emitters (40 mrem) Average Annual Background Radiation Exposure in the US (360 mrem)

  10. Average Annual Background Radiation Exposure in the US (360 mrem) Cosmic (29 mrem)

  11. Average Annual Background Radiation Exposure in the US (360 mrem) Terrestrial (29 mrem)

  12. Average Annual Background Radiation Exposure in the US (360 mrem)

  13. Biological Effects Risk of cancer and/or geneticeffects ? Radiation dose 100 rem

  14. Biological Effects • Effects depend on dose • Can range from no effect (low dose) to death (high dose) with acute doses • Damage to DNA considered most significant • Single strand break- repaired easily • Double strand break- rare but not repaired easily • DNA strands break thousands of times an hour under normal situations and the body repairs it. Increased risk of cancer with radiation can occur when there is an increase of occurrence causing a higher probability that strands do not get fixed • This is only one of several steps required to induce tumors

  15. Biological Effects • Acute (one-time) high level dose • Can cause radiation damage and symptoms quickly • Not likely with any sources on campus • Chronic (long-term) low level dose • Effects, if any, appear after 20-30 years • Risk of cancer with 1 rem of radiation increases from the normal rate of 20% to 20.03%.

  16. Ionizing Radiation Regulations • Radioactive material users must be licensed by the Nuclear Regulatory Commission or state agency • Radiation Safety Officer (RSO) makes procedures manual which must be followed because it is enforceable by law • Must assure compliance with the Nuclear Regulatory Commission, Department of Transportation, Indiana State Department of Health, and Indiana Department of Environmental Management Regulations.

  17. Exposure Limits • Radiation workers can receive a whole body dose of 5000 mrem/yr • Pregnant radiation workers can receive 500 mrem/9 month gestation period • Minors are limited to 10% of adult doses • Public is limited to 100 mrem/year • Average dose the public receives is 360 mrem/yr • Average dental x-ray- 10 mrem • Head/neck x-ray- 20 mrem • Cross-country airline flight- 5 mrem

  18. Radiation Safety Guidelines • Warn everyone about presence of radionuclides • Label all radioactive materials • Lock up radionuclides • Wear PPE • Conduct surveys • Keep records/inventory of radioactive materials (RAM) • Contact RSO before moving any materials to a different location

  19. Radiation Safety Guidelines • Make sure special equipment is ordered ahead of time • Develop a contingency plan in case of accident • Be sure to have proper personnel dosimetry (film badges, finger badges) if applicable

  20. Radiation Safety Guidelines • Proper monitoring equipment in working condition • Proper shielding design (consult RSO) • Make sure Principal Investigator is approved for specific nuclide and quantity

  21. Geiger- Mueller Counters • For contamination and exposure determination • Good audible response • Can saturate at high count rates - use audio • Cannot detect low energy betas very efficiently (S-35, C-14, H-3)

  22. Security-NRC Main Area of Emphasis • Secure laboratories when unoccupied • Secure RAM if laboratory security is not feasible • Challenge visitors or unauthorized individuals • Account for RAM through inventory records

  23. Emergency Procedures: Injury • Assist injured personnel first, call 911 if serious injury (Medical problems take priority over radiological concerns). • Monitor personnel, check for contamination. • Control area - inform other workers and keep people out of the area. • Notify radiation safety office at REM- 46371.

  24. Emergency Procedures: Fire • Sound fire alarm. • Contact fire department. Inform them of the incident. • Turn power off to system if using x-ray or other radiation-producing device, if possible. • Evacuate area or use fire extinguisher. • Contact REM (49-46371).

  25. REM Contact List • REM Main Number- 46371 • Jim Schweitzer- 42350 • Radiation Safety Officer and Director, REM • Mary Handy- 42721 • Laser Safety Officer / Health Physicist • Mark Pflug- 42693 • Health Physicist • Deb Smith- 40205 • Health Physicist

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