Ionizing and Non-Ionizing Radiation CHEM 605 Fall 2009

1. Ionizing and Non-Ionizing Radiation CHEM 605Fall 2009 Contents: This information is intended to contribute to a level of understanding for which any person with an advanced degree in a physical science should be held responsible. (i.e. it’s pretty basic.)

2. Definitions • Radiation • Electromagnetic energy. Some is essential to life as we know it. Some is hazardous. • Radioactivity • Spontaneous emission of particles and/or electromagnetic radiation from an unstable nucleus.

3. Definitions • Ionizing Radiation • EM radiation of sufficient energy to strip (dislodge) orbital electrons. • Non-Ionizing Radiation • EM radiation which does NOT have enough energy to dislodge orbital electrons.

4. Spectrum from OSHA

5. Spectrum from W.H.O.

6. Definitions • Contamination • Radioactive material in an unwanted location. • Half-Life (“t1/2”) • The time required for the activity to become half of what it was. (at t0)

7. Occ Safety links. • www.osha.gov/SLTC/radiation/index.html • www.osha.gov/SLTC/radiationionizing/index.html • www.osha.gov/SLTC/radiation_nonionizing/index.html

8. Ionizing Radiation Examples FOUR • There are 4 main types of radioactive emissions, each of which has different shielding requirements Alpha -- blocked (shielded) by air, skin, paper Beta -- blocked by skin, Al, wood, Plexiglas Gamma/x-rays -- shielded by lead (Pb) Neutrons – blocked by H- containing materials, water, paraffin…. .

9. Non-Ionizing Radiation and sources • Lasers • Radiofrequency • Cell phones • Antennas • Microwaves • Power stations • Magnets • MRI/NMR • Cathode ray tubes • Charged particle beams • Mass spectrometers • Solenoid valves • Magnetic trains

10. IONIZING -- Exposure • TWO exposure possibilities • Internal (ionizing only) • Inhalation, ingestion, absorption, injection. • Main concern is αalpha and low energy β • External • Energy absorbed • higher energy β, γ, and n radiation

11. IONIZING Radiation Reducing Exposure • Time – short time is better time of exposure. • Distance – farther away is better • Shielding – shielding is better • Contamination Control (ionizing only) • PPE • Surveys

12. BACKGROUND IONIZING Radiation • Average Annual Background Radiation Exposure in the US is approximately 360 mrem • rem == “röntgenequivalent in man, a unit of dose .

13. Ionizing radiation the Biological Effects • Effects depend on the dose • From NONE to DEATH. Pretty wide range. • Damage to DNA can be significant • Single strand break- body repairs easily • Double strand break- rare but not repaired easily

14. IONIZING radiation Regulatory issues • Radioactive material users must be licensed, trained. • Purdue works hard to maintain its NRC license. • RSO == Radiation Safety Officer.

15. Ionizing radiation regulated Exposure limits • Annual occupational limit. (5K mrem) • Lower for pregnant workers (500 mrem/9 mo) • It’s different for minors (10% adult dose) BTW the average dose of “the public” is 360 mrem/yr Average dental x-ray = 10 mrem Head/neck x-ray = 20 mrem Cross-country airline flight = 5 mrem

16. IONIZING radiation Your SOP. • Comprehensive guidelines required. Warnings, training, labeling, security, PPE, dosimetry, surveys, records, shielding, licensing, contingency plan, storage, use, transportation.

17. IONIZING radiation a note on GM Counters • Geiger- Mueller. (Geiger was the professor. Meuller was the grad student.) • GM counters DO NOT detect low energy betas efficiently (S-35, C-14, H-3)

18. NONIONIZING radiation LASERs Light Amplification by Stimulated Emission of Radiation

19. Laser Hazard Classification Scheme • Class 1: normally cannot produce a hazard. • Class 2: maybe, if extended exposure. • Class 3a: not if viewed for short periods. • *Class 3b: hazardous if viewed directly or reflected • *Class 4: very hazardous if viewed directly or reflected, and also by diffuse reflection. ALSO may produce fire hazards and skin hazards. * 3b and 4 Required to be registered with the REM laser safety program.

20. 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.

21. Non-ionizing -- Biological Effects: Laser: Beam Hazards • Eye Damage • Skin Damage

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

23. Postings - Laser

24. Non-ionizing -- Biological Effects: Radiofrequency (not lasers anymore) • 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.

25. Postings – RF/EME

26. Non-Ionizing -- Biological Effects Magnets • Can effect electromagnetic devices (e.g. pacemakers, insulin pumps) • Attract ferrous objects, both inside and outside body (i.e. flying metal objects!) • At 2 T or greater (static magnets): • Nauseousness, vertigo, magnetophosphenes (i.e. flickering light in eyes) • Induction of electrical potential within blood

27. Postings - Magnet

28. That was it. • NOTE -- you are responsible to check your record and make sure all grades are there, all attendance is correct. There will not be more reminders, and the consequences of continued neglect of this detail could be very unpleasant.