Working Correctly & Safely with Radiation. Talia Tzahor Radiation safety officer Tel:

Transcription

1 Working Correctly & Safely with Radiation Talia Tzahor Radiation safety officer Tel:

2 Environmental Exposure The typical human body contains: Potassium-40 ( 40 K) & Carbon-14 ( 14 C) with an activity of ~2 0.1 μci Ionizing Radiation from natural sources in Israel 3 msv/y (~300mR)

3 So. Radiation? Radiation - energy given by an unstable atoms. Ionizing radiation - has the ability to change the physical state of atoms it interacts with, causing them to become electrically charged or IONIZED. There are 4 main types of ionizing radiation: Alpha particles, Beta particles, Photons (gamma or X-rays) & Neutrons.

4 Ionizing Radiation types Alpha Particles (α): 2 neutrons & 2 protons, heavy mass. Beta Particles (β): Electrons or positrons with a small mass and variable energy Gamma (γ) and X-rays: forms of electromagnetic radiations or photons have no mass

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6 Radiation unites Curie (Ci) - The unit of radioactivity 1 Ci = decays per second. 1 mci= 37 MBq (10 6 ) Becquerel (Bq) - equates to 1 decay per second

7 Half Life Time The time taken for half the radionuclide's atoms to decay Activity 100% P-32 T 1/2 = 14.2 days 50% 25% 12.5% days

8 Commonly used Radioisotopes at WIS Radionuclide Type decay Half life (T 1/2 ) Energy (electron volt) Critical organ ALI Annual limit intake H-3 β 12.3y mev All body 13 mci C-14 β 5600y 0.16 mev Fat tissue 0.9 mci S-35 β 87.5d 0.17 mev Lungs 0.6 mci P-32 β 14.2d 1.7 mev Bone mci P-33 β 25.3d 0.25 mev =/= 6-8 mci Cr d 0.32 mev Colon mci I d mev Thyroid 30 uci

9 Ionizing Radiation damages Causes breaks in one or both DNA strands or; Causes Free Radical For radiation

10 Radiation Protection Time- Keep your time of exposure to a minimum Short time low exposure Distance- Radiation intensity falls off quickly with distance (inverse square law) double distance ¼ exposure Shielding- Use appropriate screen type: Lead / Poly shielding

11 Alpha Paper Plastic Lead Concrete Beta 0 0 Gamma and X-rays 1 0 n Neutron

12 Screens / Shielding Lead - for radiation Perspex - for radiation

13 Distance & Shielding

14 Radioactive station

15 Radioactive waste For all radioactive waste use the yellow barrel

16 UV radiation not an ionizing radiation

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18 UV radiation UV radiation is an electromagnetic radiation between nm wavelength. UV-A: long wavelength range nm UV-B: in range of nm UV-C: short wavelength range nm. UV-B and UV-C making more damages

19 UV light damages UV-C UV-A UV-B immediately damages: skin burn, edema, eye inflammation. Future damages: melanoma, skin inflammation, cataract, cornea damage.

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21 device with UVA light UV table UV lamp

22 Biological hood UVC light It is forbidden to use a hood without a safety switch

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24 Safely work with UV nitrile gloves face or eye shield Long sleeves lab robe

25 X-ray tube An x-ray tube requires a source of electrons, a means to accelerate the electrons, and a target to stop the high-speed electrons. Cathode (-) Anode (+)

26 Two main uses: Diffraction [XRD] X-ray scattering from crystalline materials. fingerprint of crystalline atomic structure. Check known library vs. unknown sample. Fluorescence [XRF] Analytical method for determining the elemental composition of a substance.

27 Causes of Exposure Using ANALYTICAL X-ray Putting fingers in X-ray beam to change sample Aligning X-ray beam visually Modification of shielding Failure to read & follow manufacturers X-ray operating instructions Any of these actions could cause an unnecessary exposure and a potential negative effect.

28 X-Ray effects The effects of x-ray exposure depends upon: TIME - How long is the Exposure. ENERGY - How much energy was in the x-ray Low Energy (<50 KeV) - damage only to skin or outer part of body High Energy - damage to internal organs TOTAL DOSE- The quantity of the dose

29 Radiation Protection Time- Keep your time of exposure to a minimum Short time low exposure Distance- Radiation intensity falls off quickly with distance (inverse square law) double distance ¼ exposure Shielding- Use appropriate screen type as Lead Is a practical shielding material, as it is very dense and has a high atomic number.

30 shielding X-Ray Diffractometer

31 warning light X-Ray Machine

32 Thanks for your attention Talia Tzahor Radiation safety officer Tel: