<s>
An	O
optoelectric	B-Algorithm
nuclear	I-Algorithm
battery	I-Algorithm
(	O
also	O
radiophotovoltaic	O
device	O
,	O
radioluminescent	O
nuclear	B-Application
battery	I-Application
or	O
radioisotope	O
photovoltaic	O
generator	O
)	O
is	O
a	O
type	O
of	O
nuclear	B-Application
battery	I-Application
in	O
which	O
nuclear	O
energy	O
is	O
converted	O
into	O
light	O
,	O
which	O
is	O
then	O
used	O
to	O
generate	O
electrical	O
energy	O
.	O
</s>
<s>
This	O
is	O
accomplished	O
by	O
letting	O
the	O
ionizing	O
radiation	O
emitted	O
by	O
the	O
radioactive	O
isotopes	O
hit	O
a	O
luminescent	O
material	O
(	O
scintillator	O
or	O
phosphor	O
)	O
,	O
which	O
in	O
turn	O
emits	O
photons	B-Application
that	O
generate	O
electricity	O
upon	O
striking	O
a	O
photovoltaic	O
cell	O
.	O
</s>
<s>
A	O
beta	O
emitter	O
such	O
as	O
technetium-99	B-Algorithm
or	O
strontium-90	O
is	O
suspended	O
in	O
a	O
gas	O
or	O
liquid	O
containing	O
luminescent	O
gas	O
molecules	O
of	O
the	O
excimer	O
type	O
,	O
constituting	O
a	O
"	O
dust	O
plasma	O
"	O
.	O
</s>
<s>
The	O
surrounding	O
weakly	O
ionized	O
plasma	O
consists	O
of	O
gases	O
or	O
gas	O
mixtures	O
(	O
such	O
as	O
krypton	B-Language
,	O
argon	O
,	O
and	O
xenon	B-Protocol
)	O
with	O
excimer	O
lines	O
such	O
that	O
a	O
considerable	O
amount	O
of	O
the	O
energy	O
of	O
the	O
beta	O
electrons	O
is	O
converted	O
into	O
this	O
light	O
.	O
</s>
<s>
A	O
German	O
patent	O
provides	O
a	O
description	O
of	O
an	O
optoelectric	B-Algorithm
nuclear	I-Algorithm
battery	I-Algorithm
,	O
which	O
would	O
consist	O
of	O
an	O
excimer	O
of	O
argon	O
,	O
xenon	B-Protocol
,	O
or	O
krypton	B-Language
(	O
or	O
a	O
mixture	O
of	O
two	O
or	O
three	O
of	O
them	O
)	O
in	O
a	O
pressure	O
vessel	O
with	O
an	O
internal	O
mirrored	O
surface	O
,	O
finely-ground	O
radioisotope	O
,	O
and	O
an	O
intermittent	O
ultrasonic	B-Application
stirrer	O
,	O
illuminating	O
a	O
photocell	O
with	O
a	O
bandgap	O
tuned	O
for	O
the	O
excimer	O
.	O
</s>
<s>
When	O
the	O
beta-emitting	O
nuclides	O
(	O
e.g.	O
,	O
krypton-85	O
or	O
argon-39	O
)	O
emit	O
beta	O
particles	O
,	O
they	O
excite	O
their	O
own	O
electrons	O
in	O
the	O
narrow	O
excimer	O
band	O
at	O
a	O
minimum	O
of	O
thermal	O
losses	O
,	O
so	O
that	O
this	O
radiation	O
is	O
converted	O
in	O
a	O
high-bandgap	O
photovoltaic	O
layer	O
(	O
e.g.	O
,	O
in	O
p-n	O
diamond	O
)	O
very	O
efficiently	O
into	O
electricity	O
.	O
</s>
<s>
A	O
failure	O
of	O
containment	O
would	O
release	O
high-pressure	O
jets	O
of	O
finely-divided	O
radioisotopes	O
,	O
forming	O
an	O
effective	O
dirty	B-Application
bomb	I-Application
.	O
</s>
<s>
A	O
simple	O
betaphotovoltaic	O
nuclear	B-Application
battery	I-Application
can	O
be	O
constructed	O
from	O
readily-available	O
tritium	O
vials	O
(	O
tritium-filled	O
glass	O
tubes	O
coated	O
with	O
a	O
radioluminescent	O
phosphor	O
)	O
and	O
solar	O
cells	O
.	O
</s>
