1. General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 4.3 Radiation Measurement Chapter 4 Nuclear Chemistry © 2013 Pearson Education, Inc. Lectures

2. © 2013 Pearson Education, Inc. Chapter 4, Section 3 2 Radiation Measurement A Geiger counter  detects beta and gamma radiation.  uses ions produced by radiation to create an electrical current.

3. © 2013 Pearson Education, Inc. Chapter 4, Section 3 3 Radiation Units Units of radiation include  curie (Ci), which measures activity as the number of atoms that decay in one second for one gram of radium,  rad (radiation absorbed dose), which measures the radiation absorbed by the tissues of the body,  rem (radiation equivalent), which measures the biological damage caused by different types of radiation,

4. © 2013 Pearson Education, Inc. Chapter 4, Section 3 4 Radiation Units (continued)  becquerel (Bq), which is 1 disintegration per second and the SI unit for radioactivity,  gray (Gy), which is defined as the joules of energy absorbed by 1 kilogram of body tissue and is equal to 100 rad, and  sievert (Sv), which is the SI unit for rem, and is equal to 100 rem.

5. © 2013 Pearson Education, Inc. Chapter 4, Section 3 5 Units of Radiation Measurement

6. © 2013 Pearson Education, Inc. Chapter 4, Section 3 6 Exposure to Radiation Exposure to radiation occurs from  naturally occurring radioisotopes, including potassium-40.  medical and dental procedures.  air travel, radon, and smoking cigarettes.

7. © 2013 Pearson Education, Inc. Chapter 4, Section 3 7 Radiation Sickness  Exposure to radiation of less than 25 rem is usually not detected.  Whole-body exposure of 1 Sv produces a temporary decrease in the number of white blood cells.  Exposure to radiation greater than 1 Sv may cause radiation sickness.

8. © 2013 Pearson Education, Inc. Chapter 4, Section 3 8 Radiation Sickness  This amount of radiation to the whole body is called the lethal dose for one-half the population, or the LD 50.  LD 50 varies for different life forms.  For people, whole body radiation of 6 Sv or greater would be fatal within a few weeks.

9. © 2013 Pearson Education, Inc. Chapter 4, Section 3 9 Learning Check Which unit of radiation measurement measures biological damage? A. rad B. Bq C. rem D. activity

10. © 2013 Pearson Education, Inc. Chapter 4, Section 3 10 Solution Which unit of radiation measurement measures biological damage? C. rem