University of Notre Dame

1. University of Notre Dame Department of Risk Management and Safety

2. Machine ProducedRadiation SafetyTraining University of Notre Dame Risk Management and Safety

3. Radiation Safety • Overview • Ionizing Radiation • Sources • Effects • Dosage • Risks of Exposure • Minimizing Risk • Safety in Radiation Producing Machine Use

4. Ionizing Radiation • Radiation • Energy in the form of a Particle or Electromagnetic Wave • Emitted from atoms or via effects applied to charged particles • Ionizing Radiation • Radiation with sufficient Energy to eject an electron from an atom

5. Sources Extraterrestrial Cosmic Radiation Solar Radiation Terrestrial Atomic Decay Radiation Producing Machines Particle Accelerators Nuclear Reactors Internal Atomic Decay Types of Ionizing Radiation Alpha particles Radioactive decay He nucleus Beta particles Radioactive decay / particle accelerators “free” electron Neutrons Radioactive decay / nuclear reactors Particle X-rays/Gamma Rays Radioactive decay Radiation Producing Machines Electromagnetic Wave Ionizing Radiation - Sources

6. X-ray Radiation Primary radiation source for diffraction experiments Penetrates matter Dose depends on several factors “Hardness” of X-rays Exposure time Distance Effects of Ionizing Radiation Energy from radiation can eject an electron Radical formation Radicals react strongly with other molecules Scission of atomic bonds Fragmentation of molecules Ionizing Radiation - Effects

7. Effects: Most of the damage is rapidly repaired If repair is faulty, burns (erythema) and mutations can occur Erythema most common side-effect Mutations include: Alteration of local DNA Cancer Cell Death Exposure Units are measured in Röntgen (Roentgen) (R) 1 Röntgen is 2.58 x 10-4 Coulomb (C) of charge yielded by energy given to 1 kg of air. Usually measured in milliRöntgen (mR) Doses measured in mR/h Ionizing Radiation - Effects

8. Radiation Absorbed Dose (RAD) Quantifies amount of energy released to matter from any radiation source 1 RAD = 100 erg/g of matter Measured in Gray (Gy) 1 Gy = 1 J/kg = 100 RAD Radiation Equivalent Man (REM) Quantifies biological impact of a radiation dose rem = RAD x weighting factor Weighting factor accounts for radiation type X-rays = 1 Alpha particle = 20 Measured in Sieverts (Sv) 100 mrem = 1 Sv Ionizing Radiation - Dosage

9. Radiation Limits Set by the World Health Organization (WHO) via Nuclear Regulatory Committee (NRC) 500 mrem/yr - General Public Exposure is chronic Sources Contributing to Count Background ~300 mrem/yr Radon Ingested Food Terrestrial Cosmic Radiation Indirect Medical X-rays ~50 mrem/yr Direct Medical X-rays Ionizing Radiation - Dosage

10. Ionizing Radiation • There is thought to be no lower limit to potential detrimental effects occurring from an exposure • Small increase in birth defects and cancers due to acute exposure. • Cancer risk increase is 0.04% per rem of exposure

11. Radiation Notices • Radiation Producing Machines are required to display a notification when energized • Clear notification of an open port/open shutter must be apparent (visual notification)

12. Length of time “Fleeting” exposure? Prolonged exposure? Long period of time allows more radiation to be absorbed, higher risk of deleterious effects Minimize amount of time near a potential radiation source Shielding Appropriate for Radiation? Appropriate for Instrument? Distance Radiation “suffers” from a 1/r2 decay from source Radiation is absorbed by matter; air is matter Energy dependant Exposure Prevention

13. Radiation Notices • International Standards for Radiological Work • Magenta-on-Yellow or Black-on-Yellow Trefoil • Notices must be apparent and external to the work area

14. Radiation Producing Machines (RPM) RPM X-rays are “soft” Nearly all of energy is deposited in matter Primary Beam Acute exposure High dose (100’s – 1000’s of R/min) Less likely due to beam-stop Secondary Scatter Lower count rate (~0.2 mR/h) More likely since is scattered radiation from sample Extremity rather than whole body Easily detected with a radiation counter Exposure Risks

15. Distance Decay I2 = I1 . (x1/x2)2 I2 = Dose at x2 I1 = Dose at x1 x1 = Distance 1 x2 = Distance 2 Sample is measured at 25 mR/h at 0.1 m from source, what is the dose at 0.3 m from the source 25 mR/h x (0.1/0.5)2 25 mR/h x 0.04 = 1mR/h Exposure Prevention Nota Bene: On Radiation Producing Machines the counter should read no more than 0.2 mR/h at 5 cm from the sample (back scatter)

16. Shielding Primary prevention/protection Appropriate Shielding is required Radiation sources and appropriate shielding Alpha particle: Paper Beta particle: Plastic/thin metal X-rays: metal sheeting/leaded glass Gamma Rays: lead-lined metal sheeting Neutrons: water, paraffin, plexiglass Do NOT remove radiation shielding Contact a supervisor or Radiation Safety Officer if you need to do so Do NOT override safety interlocks Exposure Prevention

17. Pregnancy – A Right to Declare • A pregnant co-worker has the right to declare the pregnancy • Declaration must be in writing, dated and signed • If a pregnancy is declared, the dose limit to the fetus is 500 mrem over the entire pregnancy (<45 mrem/month) • The declaration may be revoked • If a pregnancy is not declared, no special safety considerations are implemented

18. Safety Guidelines • First and foremost: Safety is Common Sense • All of the commentary leads to: ALARA As Low As Reasonably Achievable Consider what you are doing Consider what the risks are Minimize those risks Be Mindful

19. Pregnancy – A Right to Declare • A pregnant co-worker has the right to declare the pregnancy • Declaration must be in writing, dated and signed • If a pregnancy is declared, the dose limit to the foetus is 500 mrem over the entire pregnancy (<45 mrem/month) • The declaration may be revoked • If a pregnancy is not declared, no special safety considerations are implemented

20. Safety Guidelines • The campus Radiation Safety Manual is available in the Laboratory • At any time you may utilize the Geiger counter if you are unsure about the radiation safety of an instrument • If you have a concern you may: contact a supervisor, the Radiation Safety Specialist (Notre Dame: Andy Welding, RM&S, ext. 1-5037), the Nuclear Regulatory Commission (NRC, 1-800-695-7403)(radioactive materials), or the Indiana State Department of Health (ISDH, 1-317233-7564)(machines.) Please contact a supervisor first if possible. • If there is an accident call 911 or 1-5555 from a campus phone

21. General Laboratory Safety • The X-ray Facility is considered a Laboratory • Please exercise the same precautions you would in any Laboratory: • Long pants/dress (below knee length) • Close-toed shoes • No Food in the Facility • No Drink in the Facility • Be mindful of your actions