Nuclear Clocks
The Understanding the Atom Series
Nuclear Energy is playing a vital role in the life of every man, woman, and child in the United States today. In the years ahead it will affect increasingly all the peoples of the earth. It is essential that all Americans gain an understanding of this vital force if they are to discharge thoughtfully their responsibilities as citizens and if they are to realize fully the myriad benefits that nuclear energy offers them.
The United States Atomic Energy Commission provides this booklet to help you achieve such understanding.
Edward J. Brunenkant, Director Division of Technical Information
UNITED STATES ATOMIC ENERGY COMMISSION
Dr. Glenn T. Seaborg, Chairman
James T. Ramey
Wilfrid E. Johnson
Francesco Costagliola
by Henry Faul
CONTENTS
[INTRODUCTION] 1 [THEORY OF NUCLEAR AGE DETERMINATION] 5 [THE CARBON-14 CLOCK] 9 [Carbon-14 Counting] 12 [Carbon-14 Results] 15 [THE LONG-LIVED CLOCKS] 19 [The Rubidium-Strontium Clock] 20 [The Uranium Fission Clock] 24 [Plumbology] 27 [THE AGE OF THE EARTH] 27 [Analytical Techniques] 31 [Minerals That Can Be Dated] 34 [SOME INTERESTING RESULTS] 40 [The Old Man From Olduvai] 40 [The Geologic Time Scale] 41 [Precambrian Stratigraphy] 47 [AND WHERE DO WE GO FROM HERE?] 48 [GLOSSARY] 49 [APPENDIX] 52 [SUGGESTED REFERENCES] 58
United States Atomic Energy Commission
Division of Technical Information
Library of Congress Catalog Card Number: 67-60195
1966; 1968(Rev.)
A 14,000-year-old burial site being uncovered in the area of the Aswan Reservoir in Sudan. To determine the age of such ancient remains, archaeologists search for every scrap of associated wood or charcoal that could be used for age measurement of carbon-14, one of the “nuclear clocks” described in this booklet.
By HENRY FAUL