Radiation Laboratory Activity:
Part I: Penetrating Ability
(Sr-90  Source @ 3 cm)
Shielding material (@ 1cm) Counts Per Minute (cpm)
None
Manila - 1 sheet
- 2 sheets
Aluminum - 1 sheet
- 2 sheets
Lead - 1 sheet
- 2 sheets
Questions:
1. Of the shielding materials tested, which
a. Is the most effective in blocking radiation?
b. Is the least effective?
2. How effective was doubling the shield thickness in
blocking radiation intensity
a. for manila?
b. for aluminum?
c. for iron?
3. What properties of a material do you think
determine its radiation shielding ability?
Part II: Effect of Distance on Intensity
(Co-60  Source)
Distance
Counts Per Minute (cpm)
3 cm
6 cm
12 cm
18 cm
24 cm
30 cm
Sketch the Graph:
Questions:
4. By what whole-number factor did the intensity of
radiation decrease when the initial distance was
doubled?
5. Did this same whole-number factor apply when the
distance was doubled again?
6. Try stating the mathematical relationship
between distance and intensity.