<s>
A	O
gamma	B-Algorithm
counter	I-Algorithm
is	O
an	O
instrument	O
to	O
measure	O
gamma	O
radiation	O
emitted	O
by	O
a	O
radionuclide	O
.	O
</s>
<s>
Unlike	O
survey	O
meters	O
,	O
gamma	B-Algorithm
counters	I-Algorithm
are	O
designed	O
to	O
measure	O
small	O
samples	O
of	O
radioactive	O
material	O
,	O
typically	O
with	O
automated	O
measurement	O
and	O
movement	O
of	O
multiple	O
samples	O
.	O
</s>
<s>
Gamma	B-Algorithm
counters	I-Algorithm
are	O
usually	O
scintillation	O
counters	O
.	O
</s>
<s>
A	O
detector	O
,	O
such	O
as	O
a	O
photomultiplier	B-Algorithm
tube	I-Algorithm
converts	O
the	O
visible	O
light	O
to	O
an	O
electrical	O
signal	O
.	O
</s>
<s>
Depending	O
on	O
the	O
half-life	B-Application
and	O
concentration	O
of	O
the	O
sample	O
,	O
measurement	O
times	O
may	O
vary	O
from	O
0.02	O
minutes	O
to	O
several	O
hours	O
.	O
</s>
<s>
If	O
the	O
photon	B-Application
has	O
too	O
low	O
of	O
an	O
energy	O
level	O
it	O
will	O
be	O
absorbed	O
into	O
the	O
scintillation	O
crystal	O
and	O
never	O
be	O
detected	O
.	O
</s>
<s>
If	O
the	O
photon	B-Application
has	O
too	O
high	O
of	O
an	O
energy	O
level	O
the	O
photons	B-Application
may	O
just	O
pass	O
right	O
through	O
the	O
crystal	O
without	O
any	O
interaction	O
.	O
</s>
<s>
Thus	O
the	O
thickness	O
of	O
the	O
crystal	O
is	O
very	O
important	O
when	O
sampling	O
radioactive	O
materials	O
using	O
the	O
Gamma	B-Algorithm
Counter	I-Algorithm
.	O
</s>
<s>
Gamma	B-Algorithm
counters	I-Algorithm
are	O
standard	O
tools	O
used	O
in	O
the	O
research	O
and	O
development	O
of	O
new	O
radioactive	O
compounds	O
used	O
for	O
diagnosing	O
(	O
and	O
treating	O
disease	O
)	O
as	O
in	O
PET	B-Application
scanning	O
.	O
</s>
<s>
Gamma	B-Algorithm
counters	I-Algorithm
are	O
used	O
in	O
radiobinding	O
assays	O
,	O
radioimmunoassays	O
(	O
RIA	O
)	O
and	O
nuclear	O
medicine	O
measurements	O
such	O
as	O
GFR	O
and	O
hematocrit	O
.	O
</s>
<s>
Some	O
gamma	B-Algorithm
counters	I-Algorithm
can	O
be	O
used	O
for	O
gamma	O
spectroscopy	O
to	O
identify	O
radioactive	O
materials	O
based	O
on	O
their	O
output	O
energy	O
spectrum	O
,	O
e.g.	O
</s>
<s>
as	O
a	O
wipe	B-Algorithm
test	I-Algorithm
counter	I-Algorithm
.	O
</s>
