15 3x10 3 TT TT tT 7 4 10° 137 Cs SPIKE 4 » 10° 3S § 3s 3 Qo » : 12 Sb’ SPIKE S 10+ S o > re a SOIL 9-10" 10" Fig. 6. L 0.5 l 10 MEV 15 Gamma-ray spectrum of a 9 to 10-inch-depth increment from old soil compared with the gamma spectra of sb!25 and cs}37.