1. Chapter 9
Nuclear Radiation

2. Iodine-131 or I-131 uranium-235 or U-235
Definitions
Radioactive- any unstable Nucleus that spontaneously emits energy to become more stable.
Radiation- any particle or energy that is emitted by a radioactive nucleus.
Many Isotopes are radioactive and are called Radioisotopes
Elements with atomic # greater than 84 consist only of radioactive isotopes.
Radioactive isotopes are written with the mass # after the element:
Iodine-131 or I-131 uranium-235 or U-235

7. 2 x distance from source = intensity  by (1/2)2 or ¼.
Alpha particles: stopped by air, skin and clothes, travel 2-4cm in air. eg. radium-226
Beta particles: stopped by heavy clothes, gloves and face shields, travel cm in air. eg. carbon-14
Gamma rays: stopped by lead and concrete type barriers, travel 500m in air. eg. technectium-99m
With radiation you need to protect yourself. The protection depends on what type(s) of Radiation you are exposed to:
ALPHA, but if they are internal, they can cause serious damage from the large amount of Ionization.
BETA particles are lighter, but move faster and further.
GAMMA rays are like radio waves and can pass through people and clothing easily; Lead and concrete type barriers are needed to protect you from these very harmful rays.
Keep your distance.
2 x distance from source = intensity  by (1/2)2 or ¼.

26. Biological Damage Exposure to < 25 rem cannot be detected.
Exposure to 100 rem will cause temporary depletion of WBC…….higher than this produces radiation sickness (vomiting, fatigue, further  WBC)
Exposure to about 500 rem is expected to cause death in 50% of exposed persons.
Mrem = 1/1000 rem

34. “Scan” eg…………gamma rays from a radioisotope detected on a photographic plate to give a picture of tumor, blood clot formation, thyroid function (RAIU or radioactive iodine uptake) etc.
Thyroid scan

35. “PET scan”……..positron emission topography
- a positron is a particle emitted from the nucleus that has the same mass as an electron but a positive charge.
Positron emitters used to diagnose conditions involving blood flow and brain function are carbon-11, oxygen-15 and nitrogen-13.
Carbon-11 was used to detect Michael J Fox’s Parkinson’s disease!

37. RADIATION AND FOOD

39. Nuclear Fission and Fusion
Fission – the splitting of a nucleus to yield two smaller nuclei and ENERGY.
Fusion – the joining of two smaller nuclei to yield a larger one with the release of ENERGY.
E = m c2 when the two reactions occur some mass is ‘lost’ that mass difference is converted to ENERGY.

49. “The Good, the Bad and the Ugly”
Fission:
Efficient & Cheap
Fusion:
Super Cheap and CLEAN

50. “The Good, the Bad & the Ugly”
Fission:
Lots of Radioactive wastes
Will the Uranium supply last?
DANGEROUS
Fusion:
Almost as Dangerous

51. “The Good, the Bad & the Ugly”
Fission:
Chernobyl; 3 Mile Island
Fusion:
Impossible with today’s technology