31 and BEYOND*Transmutation is the changing of one element to another by nuclear reaction.*See example 31-1 p944

31-2 Nuclear Fission*Nuclear fission is the splitting of a large nucleus into 2 or more smaller nuclei.See diagram page 948*A chain reaction is a sustainable nuclear reaction… the amount of fissionable material required for a sustained reaction is called the critical mass.•A substance known as the moderator must be used, in a reactor, to slow down the neutrons… hydrogen or heavy hydrogen are used as part of water.•The core, of a reactor contains the enriched fuel and the moderator. (fuel usually 2-4% Uranium 235)

31-3 Fusion

• Nuclear fusion is the fusing together of 2 smaller nuclei to obtain one larger nucleus.

• See Example 31-5

31-4 Passage of Radiation Through Matter: Radiation Damage

• a, B, g, and x-rays are types of radiation.• They are referred to as ionizing radiation.• DNA damage is the worst type of damage for

biological organisms.

31-5 Measurement of Radiation--Dosimetry

• Source activity is measured as disintegrations per second … the traditional unit is the Curie or Ci 1 Ci= 3.70x1010 disintegrations /sec

• 1Bq = 1 disintegrations /sec• The SI unit for dose the the gray (Gy)• 1Gy = 1J/kg= 100 rad