GAMMA RAYS
O3
1
IO
L
jl
~
R/WEEK
100
~~
i
1OO0
A
100
MEAN SURVIVAL TIME (PER CENT OF CONTROL)
100
'
7
O71
qT
I
1O
FAST NEUTRONS
-
T
iOO
RAD/WEEK
Figure XIV.
Mean survival time expressed as percentage of the control survival,
as a funetton of the weekly dose or exposure to fast neutrons or gamma rays.
The ganna and neutron seales are in the ratio of 1:13.
The symbols refer to different sets of data obtatned on mice, rats and
guinea-pigs by vartous authors, as plotted by Mole [M13]
and tneluded in the UNSCEAR 1958 report [U1].
sponse the neutron data were intermediate between the effects of these two in«
tensities of gamma rays and nearer to those of the 110 R/week.
The RBE was
therefore estimated to be between 13 and 7, but nearer to the latter figure.
196,
In a subsequent paper by the same group [N8] the RBE value was dis-
cussed for CBA mice irradiated chronically with fast neutrons with the neutron
facilities described in [N3].
rad/day or 0.3 rad/day.
The dose-rates of the 0.7 MeV neutrons were 2.2
Gamma irradiations were run at 15.8 or 2.3 rad/day.
Complete life-table data and cumulative survival curves were obtained in repli-