the Cryogenic Dark Matter search is
exciting to me because it's discovery of
something new. We know a lot about the
universe from what we see but there's a
very large amount that we don't know
that we don't that we can give a name to
but we really don't know what it is and
that's exciting to be able to understand.
Dark matter is something that we know
exists in the universe because we see
its effects on normal matter, so when we
point telescopes out into the universe,
we see normal matter moving in a way
that it shouldn't unless there was a lot
more matter that is not emitting or
absorbing light, so we we know it exists
in the universe, now we would like to
find out is it around us and what does
it consist of.  It's much more matter than
what we can see when we look through our
telescopes and it's non luminous and
presumably does it interact very often
with normal matter and so this is what
we call dark matter and we don't know
what it is. 
CDMS or the Cryogenic Dark Matter
Search experiment, it's an astro
particle physics experiment located deep
underground in northern Minnesota in the
Sudan underground laboratory, which is an
old iron mine. So the idea of this
experiment is to detect a new form of
radiation, and the way we do this is with
hockey-puck sized germanium and silicon
crystals cooled to very cold
temperatures, that's what makes it
cryogenic and shielded as best we can
from normal types of radiation that
could mimic a Dark Matter signal, and so
we placed these things in this well
shielded underground installation and
search for a signature of some new form
of radiation interaction that we cannot
identify as normal a normal type of
interaction.  The best hypothesis for what
dark matter is made of is called a
weakly interacting massive particle or
WIMP.
So dark matter could be made of these
particles and dark matter is around us.
We believe the Milky Way galaxy has an
enormous halo of dark matter that we're
moving through. If it's made of these
WIMPS, since they don't interact with
normal matter very often, they're passing
through us all the time even as we sit
here they're passing through us very
occasionally one of them will bump into
the nucleus of an atom if you have one
of these detectors chilled-out to that
to the level where you can see that then
you could potentially detect that dark
matter particle. We attempt to create the
deepest darkest quietest coldest
environment that we can and we put
special radiation detectors in that
environment and we wait, we wait for some
new type of radiation that we've not
seen before to ping our detectors and
cause them to vibrate and hopefully that
is the dark matter. We had a few events,
candidate dark matter events that were
unable to positively say this is some
kind of normal radiation or background
that we know about, however only a couple
events is is not enough to provide a
convincing detection of the dark matter
and we've also learned things to suggest
how we should further improve our
detectors and towards a next-generation
experiment and hopefully detect the dark
matter eventually. There's an enormous
amount of matter in the universe that we
can't see and that we know nothing about.
As scientists our mission is to
understand the universe and what's in it
and so we really want to understand what
is this matter made of is it made of
particles like these WIMPS, is it made of
something else?  It's really a driving
force for us an exciting thing for us to
try to understand what a large part of
the universe is made out of.
