1. Basics of Radiation

2. 2 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

3. 3 Two Types of Radiation Radiation can be non-ionizing or ionizing Non-ionizing radiation is generally a low energy electromagnetic wave –Sunlight –Radio waves –Microwaves –Infrared waves Mostly harmless

4. 4 Ionizing (Nuclear) Radiation Has enough energy to ionize (alter) atoms and molecules Because it can ionize, it can cause biological damage

5. 5 Ionizing Radiation Ionizing radiation is all around us Outer space, the earth, and medical treatments Low levels of naturally occurring radioactive material are in our environment, the food we eat, and in many consumer products Some consumer products also contain small amounts of man-made radioactive material Most of your annual dose of radiation comes from Radon gas in your house

6. 6 Types of Ionizing Radiation

7. 7 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

8. 8 What is a Dose of Radiation? When radiation hits your body, and its energy is transferred to your tissue, you have received a dose of radiation. The more energy deposited, the higher your dose. Measured in rem (R).

9. 9 What is the Dose Rate of Radiation? The amount of radiation given off by a source over time Measured in rem per hour (R/h)

10. 10 Gatling Gun Analogy The number of bullets released per hour is the dose rate The number of bullets that hit you is the dose

11. 11 Irradiated or Contaminated? Irradiated You are irradiated when radiation hits you You do not become radioactive when you are irradiated Many foods are irradiated to kill molds and bacteria

12. 12 Irradiated or Contaminated? Contaminated Contamination is radioactive dirt You can become contaminated by touching radioactive dirt Contamination can be washed off like any dirt

13. 13 Radioactive Contamination Radiation cannot make you radioactive* * Understanding Radiation: Bjorn Wahlstrom (overrides copyright below)

14. 14 Radioactive Contamination Radioactive contamination can stick to clothes and skin. It can be washed away like any dirt*. * Understanding Radiation: Bjorn Wahlstrom

15. 15 Common Doses in Everyday Life 1R = 1,000,000 μR

16. 16 Acute Radiation Doses

17. 17 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

18. 18 Radiation Safety The fundamental principle of radiation safety is that radiation exposure should be As Low As Reasonably Achievable (ALARA). The three factors influencing radiation dose are: –Time –Distance –Shielding

19. 19 ALARA - Time The less time you’re exposed, the less exposure you get Dose = Dose Rate x Time Limit your time near the radiation source!

20. 20 ALARA - Distance The farther away from the source you are, the weaker the source is to you Exposure levels are based upon the inverse square law Increase the distance between you and the source!

21. 21 ALARA - Shielding Shielding can reduce or stop radiation from hitting you –α can be absorbed by a piece of paper –β can be absorbed by 1” of aluminum or glass –γ can be absorbed by thick lead shields –n can be absorbed by paraffin, water, polyethylene Increase the amount of shielding material between you and the source!

22. 22 Shielding/Attenuating Radiation  Paper Glass, thin metal Lead, Concrete   Water, Polyethylene 

23. 23 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

24. 24 Radiological Terrorism Radiological Terrorism is a real and possible threat High psychological/emotional impact High economic impact Many devices are easy to build Al Qaeda has threatened radiological terrorism It’s already being done

25. 25 Threat Comparison Severity of incident Probability of incident Stolen nuclear weapon Improvised nuclear device RDD

26. 26 Radiological Terrorism Nuclear warheads use special nuclear materials –Plutonium –Uranium Medical and industrial radioactive materials cannot produce a nuclear warhead – they can only be used to contaminate

27. 27 Radiological Dispersion Devices RDDs take two main forms A dirty bomb –Radiological material wrapped in conventional explosives A simple radioactive source left discretely in a public place

28. 28 Making an RDD All you need is radiological material Orphan sources –Radiological materials are used everyday in a variety of applications –Some sources are lost, forgotten, or disposed of improperly – orphan sources –Over 200,000 available today

29. 29 Example of an RDD 1 pound of HE, two patient doses of liquid Technetium- 99m (Tc-99m) near the HE Weather: 30 degrees F, sunny, light winds with gusts of 20 mph

30. 30 Example of an RDD Contamination measured at 4 times background

31. 31 Commonly Available Isotopes Suitable For RDDs *Can be detected with a gamma sensor because daughter isotope emits gamma.

32. 32 Innocent Sources Radioactive sources seen in typical day to day operations –Cause innocent alarms –Could be used to disguise a real source Containers of tile & bricks containing uranium & thorium Containers of bananas & fertilizer containing potassium Patients who have received nuclear medicine treatments

33. 33 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

34. 34 Summary Dose is measured in R –Cumulative effect on the body Dose rate is measured R/h –Amount of radiation in your vicinity Contamination is radioactive particles in or on the body Irradiation is exposure to a radioactive source

35. 35 Summary Time Distance Shielding Three factors influence radiation dose

36. 36 Questions? RAE Systems 3775 North First Street San Jose, CA 5134 Voice: 408-952-8200 Fax: 408-952-8480 www.raesystems.com

37. 37 Topics Types of Radiation How Radiation Interacts With You Radiation Safety Why Measure Radiation Today Summary Radiation Equivalents

38. 38 Radiation Equivalents RemMillirem (mrem) Microrem (µrem) 11,0001,000,000 0.1100100,000 0.011010,000 0.00111,000 0.00010.1100 0.000010.0110 0.0000010.0011

39. 39 Radiation Equivalents UnitMeasured Quantity Rad, Grey (Gy)Absorbed Dose Rem, Sievert (Sv)Biologically Equivalent Dose Unit Equivalents 100 Rem1 Sv 1 Rem10 mSv (millisievert) 1 mrem (millirem) 10  Sv (microsievert) 1  rem (microrem)0.01  Sv