<s>
The	O
Big	O
European	O
Bubble	B-Algorithm
Chamber	I-Algorithm
(	O
BEBC	B-Algorithm
)	O
is	O
a	O
large	O
detector	O
formerly	O
used	O
to	O
study	O
particle	O
physics	O
at	O
CERN	O
.	O
</s>
<s>
The	O
chamber	O
body	O
,	O
a	O
stainless-steel	O
vessel	O
,	O
was	O
filled	O
with	O
35	O
cubic	O
metres	O
of	O
superheated	O
liquid	O
hydrogen	O
,	O
liquid	O
deuterium	O
,	O
or	O
a	O
neon-hydrogen	O
mixture	O
,	O
whose	O
sensitivity	O
was	O
regulated	O
by	O
means	O
of	O
a	O
movable	O
piston	O
weighing	O
2	O
tons	O
.	O
</s>
<s>
The	O
bubble	B-Algorithm
chamber	I-Algorithm
was	O
then	O
ready	O
again	O
for	O
a	O
new	O
cycle	O
of	O
beam	O
exposure	O
.	O
</s>
<s>
The	O
conception	O
and	O
construction	O
of	O
giant	O
bubble	B-Algorithm
chambers	I-Algorithm
such	O
as	O
Gargamelle	O
and	O
BEBC	B-Algorithm
was	O
based	O
on	O
know-how	O
acquired	O
through	O
the	O
construction	O
and	O
operation	O
of	O
smaller	O
bubble	B-Algorithm
chambers	I-Algorithm
such	O
as	O
the	O
30	O
cm	O
hydrogen	O
chamber	O
,	O
which	O
came	O
into	O
operation	O
at	O
CERN	O
in	O
1960	O
,	O
and	O
the	O
2	O
m	O
hydrogen	O
chamber	O
four	O
years	O
later	O
.	O
</s>
<s>
The	O
BEBC	B-Algorithm
project	O
was	O
launched	O
in	O
1966	O
by	O
CERN	O
,	O
France	O
(	O
Saclay	O
)	O
,	O
and	O
Germany	O
(	O
DESY	O
)	O
and	O
installed	O
at	O
CERN	O
in	O
the	O
early	O
1970s	O
.	O
</s>
<s>
The	O
chamber	O
body	O
was	O
surrounded	O
by	O
the	O
then-largest	O
superconducting	O
solenoid	B-Algorithm
magnet	I-Algorithm
of	O
two	O
coils	O
in	O
a	O
Helmholtz	O
arrangement	O
.	O
</s>
<s>
The	O
BEBC	B-Algorithm
coils	O
created	O
a	O
strong	O
magnetic	O
field	O
of	O
3.5	O
T	O
over	O
the	O
sensitive	O
volume	O
of	O
the	O
chamber	O
.	O
</s>
<s>
The	O
first	O
images	O
were	O
recorded	O
in	O
1973	O
when	O
BEBC	B-Algorithm
first	O
received	O
a	O
beam	O
from	O
the	O
Proton	O
Synchrotron	O
(	O
PS	O
)	O
.	O
</s>
<s>
During	O
1978	O
,	O
a	O
Track-Sensitive	O
Target	O
(	O
TST	O
)	O
was	O
installed	O
to	O
combine	O
the	O
advantages	O
of	O
hydrogen	O
and	O
heavy	O
liquid	O
bubble	B-Algorithm
chambers	I-Algorithm
.	O
</s>
<s>
An	O
External	O
Muon	O
Identifier	O
(	O
EMI	O
)	O
and	O
an	O
External	O
Particle	O
Identifier	O
(	O
EPI	O
)	O
were	O
added	O
to	O
the	O
BEBC	B-Algorithm
in	O
1979	O
to	O
respectively	O
identify	O
muons	O
and	O
charged	O
hadrons	O
leaving	O
the	O
chamber	O
.	O
</s>
<s>
Furthermore	O
,	O
an	O
Internal	O
Picket	O
Fence	O
(	O
IPF	O
)	O
was	O
used	O
to	O
obtain	O
timing	O
signals	O
for	O
events	O
occurring	O
in	O
the	O
bubble	B-Algorithm
chamber	I-Algorithm
,	O
helping	O
to	O
suppress	O
the	O
background	O
.	O
</s>
<s>
These	O
changes	O
transformed	O
BEBC	B-Algorithm
into	O
a	O
hybrid	O
detector	O
.	O
</s>
<s>
The	O
BEBC	B-Algorithm
experiments	O
were	O
:	O
T225/231	O
,	O
T243	O
,	O
WA17	O
,	O
WA19	O
,	O
WA20	O
,	O
WA21	O
,	O
WA22	O
,	O
W24	O
,	O
WA25	O
,	O
WA26	O
,	O
WA27	O
,	O
WA28	O
,	O
WA30	O
,	O
WA31	O
,	O
WA32	O
,	O
WA47	O
,	O
WA51	O
,	O
WA52	O
,	O
WA59	O
,	O
WA66	O
,	O
WA73	O
,	O
and	O
PS180	O
.	O
</s>
<s>
By	O
the	O
end	O
of	O
its	O
active	O
life	O
in	O
1984	O
,	O
BEBC	B-Algorithm
had	O
delivered	O
a	O
total	O
of	O
6.3	O
million	O
photographs	O
to	O
22	O
experiments	O
.	O
</s>
<s>
BEBC	B-Algorithm
enabled	O
the	O
discovery	O
of	O
D-mesons	O
and	O
promoted	O
the	O
developments	O
of	O
neutrino	O
and	O
hadron	O
physics	O
,	O
carrying	O
out	O
one	O
of	O
the	O
richest	O
physics	O
programs	O
.	O
</s>
