The composite neut
capture decay curve will then be the sum
of the decay curves of tea, es, Np239, u240 | and Np240 , 1.@.,
Be = Ago (02000416270 000431t 4 o-1..77t
(3.9)
£ 0.006520 2O1L24t 4 0.014607 00495t y+
where A, = Activity due to capture products at time t and
Acos Proportionality constant
Aug can be determined from the ratio of neutron capture to
fission activity measurerents.
TABIE 3.1 - Initial
tive Actiyities of U“27, 9239
Np239, pitt and upeee
,
,
The Shot 1 decay curve vill then be the sum of Eqe 3.4
and Eqe 3e9. The experimentally determined ratio of uranium capture
products to fission products can then be used to find the value of
Ago if it is remembered that Ay, has already been determined.
A,[250
sl
Ay, (250)
(3.10)
=n 7 O88
0468 Ay(250)-% ao Aggy (Ecye™4*)
(3.11)
The curve was then normalized (set ecual to 1) to 400 hours, at which
time the activity data were knowne
The equation for the extrapolation of fission and neutron
induced activities to sampling time is then
A = 1350 t72+26 4 2200(0,000226e70+00431¢ (3-12)
# enbe77t 40.00652e 0 Ol 2hb Yo 01 46070 0049 5t )
This composite curve is showm in Fige Bele
*
The last term includes the activity of both U
39
240
and Np*
40