furnish a fairly smootii curve.
Tne peak-to-total
curve characteristic of the machine used in tne present
experiment is Snown in Fig. 6.
(3)
Counts per second per square inch in the
total absorption peak,
C.
This number is a constant
of the machine and is found by dividing the number of
counts per second per inch of deflection in the Y direction by the channel width in chart inches.
The channel
width used throughout the experiment corresponds to
O.1 inch on the chart paper and the total Y deflection
is 10 inches.
=o. ew
Ss
(4)
Then for the 200 c/s scale, C is 200.
Source reductidén factor, h.
This factor is
the fraction of photons leaving the source which enter
the crystal and takes into account effects of collimator
penetration, finite extension of source, and solid angle
subtended by the crystal from the source, assuming a
point source and an opaque collimator.
|
These effects
are discussed in some detail in a theoretical paper by
“R, L. Mather of this laboratory.”
Derived from informa-
tion contained in this paper is Fig. 7, showing K, the
source reduction factor for a point source, versus r,
the distance of the source from the collimator axis.
To find the average source reduction factor, K, to account
15