Ionizing and Non-Ionizing Radiation Awareness CHEM 605 Fall 2006

1. Ionizing and Non-Ionizing Radiation AwarenessCHEM 605Fall 2006 Mary J. Handy Health Physicist, Laser Safety Officer Dept. of Radiological and Environmental Management

2. 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. • Non-Ionizing Radiation • Radiation without sufficient energy to strip electrons from the orbit of an atom (unlike ionizing radiation), yet enough energy to excite orbital electrons. • 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

3. Ionizing Radiation Examples • 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

4. Non-Ionizing Radiation Examples • Laser • Magnet • MRIs (magnetic resonance imaging) – formally known as NMRs (nuclear magnetic resonance) • Cathode ray tubes • Charged particle beams • Mass spectrometers • Solenoid valves • Magnetic levitation trains • Radiofrequency • Cell phones • Antennas • Microwave ovens • Power stations

5. Exposure • There are two ways that an individual can be exposed to radiation • Internal exposure (ionizing only) • 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. Rules to Reduce Radiation Exposure • Time • Reduce time in areas of radiation exposure. • Distance • Keep your distance from sources of radiation exposure- exposure drops very quickly. • Shielding • Use proper shielding to reduce exposure if shielding is necessary. • Contamination Control (ionizing only) • PPE • Surveys

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

8. Biological Effects - Ionizing • 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

9. Biological Effects - Ionizing • 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%.

10. 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.

11. Exposure Limits – Ionizing Radiation • 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

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

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

14. 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)

15. 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

16. LASER Light Amplification by Stimulated Emission of Radiation Optical Cavity Lasing Medium Emitted Wavelength Fully Reflecting Mirror Pumping System Partially Reflecting Mirror

17. Laser Hazard Classification Scheme • Class 1: normally cannot produce a hazard. • Class 2: may present some potential for hazard if viewed directly for extended periods of time. • Class 3a: normally would not produce a hazard if viewed for only momentary periods with the unaided eye. • Class 3b *: can produce a hazard if viewed directly or specular (i.e. mirror-like) reflection. • Class 4 *: can produce a hazard not only from direct or specular reflections, but also from a diffuse reflection. In addition, such lasers may produce fire hazards and skin hazards. * Class 3b and 4 lasers are required to register with laser safety program.

18. Can I be in a room with a Class IIIb or IV laser if I haven’t had Laser Safety Training? Yes, as long as: • The laser is not in operation, OR • The laser system is totally enclosed (where the Nominal Hazard Zone (NHZ) is the laser system, OR • The laser system is surrounded by barriers (which would be the NHZ) and you are on the outside of the NHZ, OR • You are authorized to be in the NHZ, are wearing the appropriate laser safety equipment, AND are NOT operating the laser.

19. Biological Effects – Non-ionizing: Laser: Beam Hazards • Eye Damage • Thermal • Photochemical • Photoacoustic • Skin Damage • range from mild reddening (erythema) to blistering • depend upon exposure dose rate, exposure dose, and conduction of heat away from the site of absorption • possible carcinogenic effects

20. Biological Effects – Non-ionizing: Laser: Non-Beam Hazards • Inhalation hazards • Cryogenic Effects • Toxic/Carcinogenic Effects • Possible hearing loss • Ionizing Radiation Exposure • Lacerations • Electrocution • Burns

21. Postings - Laser

22. Biological Effects – Non-ionizing: Radiofrequency • Heating of the body • Cataracts • Developing fetus is at no greater risk than mother • Two areas of the body, the eyes and the testes, are particularly vulnerable to RF heating because of the relative lack of available blood flow to dissipate the excessive heat load. • Cancer? Conflicting studies.

23. Postings – RF/EME

24. Biological Effects – Non-Ionizing: Magnets • Could effect electromagnetic devices (e.g. cardiac pacemakers) • Attracts ferrous objects, both inside and outside body (i.e. flying metal objects!) • Occurring at 2 T or greater (static magnets): • Nauseousness, vertigo, magnetophosphenes (i.e. flickering light in eyes) • Induction of electrical potential within blood

25. Postings - Magnet

26. 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.

27. 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).

28. 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