CHAPTER XVII 



RADIOACTIVE TRACERS 



Adolf F. ^'^OIGT, Inst Hide for Atomic Researcti and Iowa Slate College 



A . Introduction 599 



B . Terminology of Radioactivity 601 



1 . Types of Radiation and Decay Processes 601 



2 . Radioactive Decay Law 604 



3. Units 605 



C . Availability of Isotopes 606 



1 . Radioisotopes Producible by Slow Neutron Activation . . . 606 



2 . Other Important Radioisotopes 607 



D. Detection and Measurement of Radioactivity 610 



1 . Ionization Chambers 610 



2 . Electroscopes 611 



3 . Counters 615 



4 . Special Measuring Techniques 621 



E. Errors and Corrections in Measurements of Radioactivity. .. . 623 



1 . Statistics of Counting 623 



2. Errors in Sample Mounting 626 



3. Self-Absorption Error 627 



4. Radioactivity Standards 630 



F. Unique Problems and Techniques in Handling Radioactive 



Tracers 630 



1 . Radiochemical Problems 630 



2. Special Problems in Using C'< 634 



3 . Isotope Dilution Method 635 



4 . Radioautographs 636 



G. Monitoring Radiation for Health and Safety 638 



1 . Calculations 638 



2 . Instruments and Methods 640 



H . Planning a Radiochemical Laboratory 643 



I . Biological Applications of Radioactive Tracers 648 



References 650 



A. INTRODUCTION 



The use of radioactive tracers in biological research was begun a 

 quarter of a century ago in the research of Hevesy (//), who studied 



599 



