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SEPTEMBER
OCTOBER
DATE
Fig. 7—Bismuth-214 effective surface amounts as a function of time,
L963,
ent in September and October 1963. The similar period for 1964 is
shown in Fig. 8. The modulation of some of the measured radionuclides
by an 8-in. snow cover in January 1964 is seen in Fig. 9. Initially, '°Sb
and “Mn were not observed to be in the gamma-ray spectrum, but as
the amount of *Zr—**Nb diminished, these nuclides were observed in
the residual amounts left after the attempt to account for all the gamma
Spectrum. If it is assumed that all gamma-ray inputs have been aceounted for and that proper calibrations for each source in the field
geometry are available, then, by multiplication of each calibration
Spectrum by the amounts of each determined to exist and addition of
all these amounts channel by channel, the original field spectrum should
be obtained. How well the reduction technique accounted for the initial
field spectrum is determined by subtracting the created spectrum from
the original field spectrum. The residual spectrum should be zero. A
residual spectrum for current data is shown in Fig. 10. The nuclides
2087] M4py CMRI M07 9 0K MM, %zr—%Np, %Cs, 1%sb, and '41, and
the 0.5 Mev radiation have been accounted for. However, neither “°La
nor '!] existed. The reduction should provide '*°La and ‘*"I to be zero
if the accounting is proper, Near-zero residual spectral amounts remain when an 11 by 11 inverted matrixis used for reduction. If only the
amounts of all gamma emitters creating energy lines, including the
'Cs, are removed, the residue of Fig, 11 exists. Here the 0.48- and