11 research outputs found
Present status of IGEX dark matter search at Canfranc Underground Laboratory
One IGEX 76Ge double-beta decay detector is currently operating in the
Canfranc Underground Laboratory in a search for dark matter WIMPs, through the
Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot
has been derived for WIMP-nucleon spin-independent interactions. To obtain this
result, 40 days of data from the IGEX detector (energy threshold 4 keV),
recently collected, have been analyzed. These data improve the exclusion limits
derived from all the other ionization germanium detectors in the mass region
from 20 GeV to 200 GeV, where a WIMP supposedly responsible for the annual
modulation effect reported by the DAMA experiment would be located. The new
IGEX exclusion contour enters, by the first time, the DAMA region by using only
raw data, with no background discrimination, and excludes its upper left part.
It is also shown that with a moderate improvement of the detector performances,
the DAMA region could be fully explored.Comment: 3 pages, 3 figures, talk delivered at the 7th International Workshop
on Topics in Astroparticle and Underground Physics (TAUP 2001), September
2001, Laboratori Nazionali del Gran Sasso, Italy (to appear in the Conference
Proceedings, Nucl. Phys. B (Proc. Suppl.)
Improved constraints on WIMPs from the International Germanium Experiment IGEX
One IGEX 76Ge double-beta decay detector is currently operating in the
Canfranc Underground Laboratory in a search for dark matter WIMPs, through the
Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion
plot, has been derived for WIMP-nucleon spin-independent interactions. To
obtain this result, 40 days of data from the IGEX detector (energy threshold E
\~ 4 keV), recently collected, have been analyzed. These data improve the
exclusion limits derived from all the other ionization germanium detectors in
the mass region from 20 GeV to 200 GeV, where a WIMP supposedly responsible for
the annual modulation effect reported by the DAMA experiment would be located.
The new IGEX exclusion contour enters, by the first time, the DAMA region by
using only raw data, with no background discrimination, and excludes its upper
left part. It is also shown that with a moderate improvement of the detector
performances, the DAMA region could be fully explored.Comment: 14 pages, 8 figures, submitted to Physics Letters B (revised version
after referee's comments, some figures added
New constraints on WIMPs from the Canfranc IGEX dark matter search
The IGEX Collaboration enriched 76Ge double-beta decay detectors are
currently operating in the Canfranc Underground Laboratory with an overburden
of 2450 m.w.e. A recent upgrade has made it possible to use them in a search
for WIMPs. A new exclusion plot has been derived for WIMP-nucleon
spin-independent interaction. To obtain this result, 30 days of data from one
IGEX detector, which has an energy threshold of ~4 keV, have been considered.
These data improve the exclusion limits derived from other germanium diode
experiments in the ~50 GeV DAMA region, and show that with a moderate
improvement of the background below 10 keV, the DAMA region may be tested with
an additional 1 kg-year of exposure.Comment: 7 pages, 2 figures, submitted to Physics Letter
Pulse Shape Discrimination in the IGEX Experiment
The IGEX experiment has been operating enriched germanium detectors in the
Canfranc Underground Laboratory (Spain) in a search for the neutrinoless double
decay of 76Ge. The implementation of Pulse Shape Discrimination techniques to
reduce the radioactive background is described in detail. This analysis has
been applied to a fraction of the IGEX data, leading to a rejection of ~60 % of
their background, in the region of interest (from 2 to 2.5 MeV), down to ~0.09
c/(keV kg y).Comment: 18 pages, 10 figure