1. RADIATION LAB TIME - DISTANCE - SHIELDING Health Physics Society - Power Reactor Section Radiation Science Education

2. Radiation Measurements #1 - Take a background measurement. Use the lower scale - counts per minute (c/m). #2 - Measure the radiation level on contact with the plate or mantle using the open window detector. #3 - Place a medium thick piece of material (wood) over the object and repeat the measurement. #4 - Place a very thick piece of material over the object and repeat the measurement. ______ c/m

3. Shielding

4. The first measurement included beta and gamma radiation from the plate/ mantle plus background radiation (alpha radiation was too weak to pass through the detector wall). All the beta radiation was shielded by the medium thick material so #3 measured gamma only. Nearly all of the gamma radiation was shielded by the very thick piece of material. + = #2 = #3 = #2 - #3 background #4

5. Shielding If you increase the shielding around a radiation source, it will decrease your exposure. If you stand out in the rain without an umbrella, you will get wet. But, if you use an umbrella to shield you from the rain, you will remain dry and protected.

6. Distance Measure the radiation level at the surface of the plate or mantle. Move 2 inches away and repeat the measurement. Move 12 inches away, repeat the measurement. Move 3 feet far away, repeat the measurement. ______ c/m

7. Distance The farther away you are from a radiation source, the less exposure you will receive. Compare this to sitting in front of a fireplace. You can sit directly in front or across the room. If you are far from the source, your exposure would be much lower.

8. Time Place the lantern mantle in your pocket and take a open window measurement. If you leave it there for 4 hours, how many counts does your leg see? If you leave it there for 24 hours, how many counts does your leg see? _________ c/m c/m * 4 hours * 60 min/hr = _____ counts c/m * 24 hours * 60 min/hr = _____ counts

9. Time Decrease the amount of time you spend near the source of radiation, and decrease the amount of radiation exposure you receive. If you spend a lot of time on the beach, ultimately you get a sunburn. But, if you spend less time in the sun, you wont.