The Los Alamos 
Human Counter 
Take 140 gallons of liquid scintillator, 
scan it with 108 photomultipliers, 
shield it with 20 tons of lead . . . 
then you've got the essentials of a counter 
that will determine the gamma activity _ 
of body potassium to 5% in 100 secon 
By ERNEST C. ANDERSON, ROBERT L. 
SCHUCH, JAMES D. PERRINGS, and 
WRIGHT H. LANGHAM 
Los Alamos Scientific Laboratory 
University of California 
Los Alamos, New Mexico 
FIG. 1. Counter outside of lead shield 
FIG. 2. General view of counter showing lead shield, loading trough, and subject 
about to lie down in sling that will carry him into counter 
