14—16.
EFFECTIVE-“CROSS—SECTION
325
From the integral—range curVes, two helium particles of ranges
0.82 and 1.2 centimeters have also been observed. TheSe are from
the reaction
.
‘
_
3L16 + 1H1 ——>
2H63.
(14—18)
14—16.
Eective—Cross—Section
(a).—The ' yield (Y), see
'
gure 14—11, may be converted into the effective—cross—section (5).
for a given transmutation in the following manner. Let AN out of
N incident particles accomplish transmutations, with the ejection
of one particle each, from a target containing ?? atoms per cubic
centimeter.
Then
‘
.
Y ="
%V
=
71
« Ax,
where Ax is the thickness of the target material. This equation
may be used directly to calculate q provided
target is sùi_
“
‘
ciently thin; i.e., the particles sûffèr only a .negligible
energylossinit.
-
Most experiments are carried- put; With
The
procedure to allow for the
of_the
incident particles is
as follows:
_
'
Ï
[
'
_
..
.
:
£’=nêî_—=n/Aë “» (14—20)
-
.
AE
AE;
_.
‘
_
AE is an 1ncrement1ntheenergyof the inCident partiCles
corrœpondmgtoanmcrem€ntAÿmtheeld PAY/AE
is the
“
‘
-
‘
TheeîectwcecmssS€C*ü®n18Prolmlmal‘“°th€ Yleld _andïÿfls
AnumencalvaluefaranefîeetwecmssetnPP1t
…
'