First results of the IGEX dark matter experiment at the Canfranc Underground Laboratory

Abstract The enriched 76 Ge double-beta decay detectors from the International Germanium EXperiment (IGEX), operating in the Canfranc Underground Laboratory with an overbuden of 2450 m.w.e., were recently upgraded to use them also in a search for WIMPs. This paper presents a description of the experiment and the data analysis as well as a new exclusion plot, σ( m ), derived from the IGEX data for WIMP-nucleon spin-independent interaction. To obtain this result, 30 days of data from one 2-kg IGEX detector, with an energy threshold E thr ∼ 4 keV, have been considered. These results improve the exclusion limits derived from other conventional ionization germanium experiments in the ∼ 50 GeV DAMA region.