<s>
GEANT	B-Application
is	O
the	O
name	O
of	O
a	O
series	O
of	O
simulation	O
software	O
designed	O
to	O
describe	O
the	O
passage	O
of	O
elementary	O
particles	O
through	O
matter	O
,	O
using	O
Monte	B-Algorithm
Carlo	I-Algorithm
methods	I-Algorithm
.	O
</s>
<s>
Originally	O
developed	O
at	O
CERN	O
for	O
high	O
energy	O
physics	O
experiments	O
,	O
GEANT-3	B-Application
has	O
been	O
used	O
in	O
many	O
other	O
fields	O
.	O
</s>
<s>
The	O
very	O
first	O
version	O
of	O
GEANT	B-Application
dates	O
back	O
to	O
1974	O
,	O
while	O
the	O
first	O
version	O
of	O
GEANT-3	B-Application
dates	O
back	O
to	O
1982	O
.	O
</s>
<s>
Versions	O
of	O
GEANT	B-Application
through	O
3.21	O
were	O
written	O
in	O
FORTRAN	B-Application
and	O
eventually	O
maintained	O
as	O
part	O
of	O
CERNLIB	B-Application
.	O
</s>
<s>
Since	O
about	O
2000	O
,	O
the	O
last	O
FORTRAN	B-Application
release	O
has	O
been	O
essentially	O
in	O
stasis	O
and	O
receives	O
only	O
occasional	O
bug	O
fixes	O
.	O
</s>
<s>
Most	O
of	O
GEANT-3	B-Application
is	O
available	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
with	O
the	O
exception	O
of	O
some	O
hadronic	O
interaction	O
code	O
contributed	O
by	O
the	O
FLUKA	B-Application
collaboration	O
.	O
</s>
<s>
GEANT-3	B-Application
was	O
used	O
by	O
a	O
majority	O
of	O
high	O
energy	O
physics	O
experiments	O
from	O
the	O
late	O
1980s	O
to	O
the	O
early	O
2000s	O
.	O
</s>
<s>
GEANT-3.21	O
based	O
programs	O
remained	O
main	O
simulation	O
engine	O
of	O
ATLAS	O
,	O
CMS	O
and	O
LHCb	O
at	O
LHC	O
until	O
2004	O
,	O
when	O
these	O
experiments	O
moved	O
to	O
Geant4-based	O
simulations	O
.	O
</s>
<s>
A	O
related	O
(	O
but	O
separate	O
)	O
product	O
is	O
Geant4	B-Application
(	O
when	O
referring	O
to	O
this	O
version	O
,	O
the	O
name	O
is	O
typically	O
no	O
longer	O
capitalized	O
)	O
.	O
</s>
<s>
It	O
is	O
a	O
complete	O
rewrite	O
in	O
C++	B-Language
with	O
a	O
modern	O
object-oriented	B-Language
design	O
.	O
</s>
<s>
Geant4	B-Application
was	O
developed	O
by	O
the	O
RD44	O
collaboration	O
in	O
1994	O
–	O
1998	O
and	O
is	O
being	O
maintained	O
and	O
improved	O
now	O
by	O
the	O
Geant4	B-Application
international	O
collaboration	O
.	O
</s>
<s>
For	O
quite	O
some	O
time	O
Geant4	B-Application
did	O
not	O
have	O
a	O
clearly	O
defined	O
software	O
license	O
.	O
</s>
<s>
Geant4	B-Application
is	O
now	O
available	O
under	O
the	O
.	O
</s>
