|
Professor
Snowden-Ifft is performing a search for dark matter in our galaxy. Since
arriving here, Professor Snowden-Ifft has actively
involved several Oxy undergraduates in his research. The following is the
project summary from his NSF proposal submitted in the Fall of 1998.
The dark matter problem is one of
the great puzzles in modern cosmology. Simply put there is much more dark
mass than light-emitting mass in the universe. Though the existence of
dark matter is no longer in doubt its nature has remained elusive. Decades
of research by theorists and experimentalists have whittled down the number
of viable dark matter candidates to a few, among them the Weakly Interacting
Massive Particle (WIMP). The goal of this project is to detect WIMPs.
Hundreds of experimental physicists
have spent the last 20 years attempting to detect this attractive dark
matter candidate. The direct approach is to detect atoms elastically recoiling
from galactic bound WIMPs. The problem is that the recoil energies and
rates are predicted to be very small. Building on prior experience in dark
matter searches and detector techniques the present PIs D. Snowden-Ifft,
Occidental College; C. J. Martoff, Temple University, and collaborators
in Great Britain, are proposing to build a 1 m^3 TPC operating in a new
mode, discovered by the PIs, and use it to search for WIMP dark matter.
This new mode drifts negative ions, instead of electrons, and has many
advantages. Several years of intense study and experimentation have validated
the technique. The Directional Recoil Identification From Tracks (DRIFT)
detector, despite using gas as a target, has a sensitivity better than
current limits. The detector design is scalable in size and is compatible
with operation deep underground. Its ability to measure components of the
range of the recoils allows DRIFT to have exceptional background rejection
and most important a strong signature for identifying a WIMP signal should
one appear.
The proposal is a for a three year
effort to build and run the DRIFT detector. In year one (starting May 1999)
the PIs will complete tests, some already in progress, on improving the
DRIFT concept. In addition the final design of the detector will be set.
In year two the detector will be assembled and tested. In year three the
detector will be moved to a low background site and data taken for a year.
Analysis will proceed simultaneously with data taking.
DRIFT has the reach and capability
to detect WIMP dark matter by the end of year three of this proposal, especially
if a signal is present at levels suggested by recent reports. If not, useful
constraints and knowledge gained from such a novel detector will inform
the field. A follow-on search with a 10-20 m^3 scaled-up detector is already
being planned with our UKDMC collaborators. As an extremely low background
detector concept DRIFT will certainly have uses beyond cosmology. |
