55 research outputs found
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
Fine structure in the α decay of 223U
Fine structure in the α decay of 223U was observed in the fusion-evaporation reaction 187Re(40Ar, p3n) by using fast digital pulse processing technique. Two α-decay branches of 223U feeding the ground state and 244 keV excited state of 219Th were identified by establishing the decay chain 223U →α1 219Th →α2 215Ra →α3 211Rn. The α-particle energy for the ground-state to ground-state transition of 223U was determined to be 8993(17) keV, 213 keV higher than the previous value, the half-life was updated to be 62−10+14 μs. Evolution of nuclear structure for N = 131 even-Z isotones from Po to U was discussed in the frameworks of nuclear mass and reduced α-decay width, a weakening octupole deformation in the ground state of 223U relative to its lighter isotones 219Ra and 221Th was suggested
THE SPIN SPECTROMETER AT THE HOLIFIELD HEAVY-ION RESEARCH FACILITY AND SOME PLANNED EXPERIMENTS
The 4π multidetector γ-ray spectrometer at the Holifield Heavy-ion Research Facility (HH IRF) is described in some detail. The following important features of this spectrometer are discussed : (a) the geometric arrangement, (b) the actual performance of the individual detector elements, (c) the associated electronics and data acquisition system, and (d) the response of the system to input γ-cascades including the effect of crystal-to-crystal scattering and the response to neutrons. The first few experiments to be performed are briefly described
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Spin spectrometer at the holified heavy-ion research facility and some planned experiments
The 4..pi.. multidetector ..gamma..-ray spectrometer at the Holified Heavy-ion Research Facility (HHIRF) is described in some detail. The following important features of this spectrometer are discussed: (a) the geometric arrangement, (b) the actual performance of the individual detector elements, (c) the associated electronics and data acquisition system, and (d) the response of the system to input ..gamma..-cascades including the effect of crystal-to-crystal scattering and the response to neutrons. The first few experiments to be performed are briefly described
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