<s>
A	O
flood	B-General_Concept
gun	I-General_Concept
is	O
an	O
electromechanical	O
device	O
that	O
provides	O
a	O
steady	O
flow	O
of	O
low-energy	O
electrons	O
to	O
a	O
desired	O
target	O
or	O
"	O
flood	O
area.	O
"	O
</s>
<s>
If	O
the	O
energy	O
of	O
a	O
flood	B-General_Concept
gun	I-General_Concept
's	O
electrons	O
is	O
properly	O
balanced	O
,	O
each	O
impinging	O
flood	B-General_Concept
gun	I-General_Concept
electron	O
knocks	O
out	O
one	O
secondary	O
electron	O
from	O
the	O
target	O
,	O
thus	O
preserving	O
the	O
net	O
charge	O
in	O
the	O
target	O
area	O
.	O
</s>
<s>
Flood	B-General_Concept
guns	I-General_Concept
are	O
typically	O
used	O
in	O
photoelectron	O
spectroscopy	O
,	O
oscilloscopes	O
and	O
ion	O
beam	O
implanters	O
as	O
their	O
secondary	O
electron	O
gun	O
.	O
</s>
