found by taking the square root of the total number of counts
contained in a rectangular area whose width is determined by
the width of the Gaussian at the point where it ceases to
coincide with the machine-drawn peak.
to be the actual area compared.

This area is presumed

The statistical error found

in this way varies widely (because of the great range in

count rate), but for the peaks tested it varles betweon 2 and
6 percent.
A hindrance to accurate superimposition of the Gaussian
curves on the total absorption peaks, contributing further
=

to the error, may be the slight non-Gaussian character of the
total absorption peak caused by the lack of perfect homoseneity

--

4

of the crystal's light production.

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To get some idea of how much of each spectrum occurred
in analyzable peaks,the total areas of several spectra were

measured with the planimeter and compared with the sums of
tne total areas associated with each listed energy (found by

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dividing

ratio).
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each peak area by the appropriate peak-to-total

It was found by this method that from 70 to 90 per-

cent of a spectrum was accounted for in the peak-by-peak

analysis.
The errors associated with the photon intensities shown
in Table 2 are the result of estimates of the cumulative
errors discussed above.

They range from 3 percent for peaks

with good resolution, good count rate,and good fit with the
23

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