18008677
Results from the ARGO-YBJ test experiment
Abstract An RPC carpet covering ∼ 104 m2 (ARGO-YBJ experiment) will be installed in the YangBaJing Laboratory (Tibet, P.R. China) at an altitude of 4300 m a.s.l.. A test-module of ∼ 50 m2 has been put in operation in this laboratory and about 106 air shower events have been collected. The carpet capability of reconstructing the shower features is presented.
121510906
Results from the ARGO-YBJ test experiment
Abstract A resistive plate counters (RPCs) carpet of ∼50 m 2 has been put in operation in the Yangbajing Laboratory (Tibet, P.R. China) at 4300 m a.s.l., in order to study the RPCs performance at high altitude and the detector capability of imaging the EAS disc. This test has been performed in view of an enlarged use of RPCs for the ARGO-YBJ experiment. This experiment will be devoted to a wide range of fundamental issues in cosmic rays and astroparticle physics, including in particular γ-ray astronomy and γ-ray bursts physics at energies ⩾100 GeV. In this paper we present and discuss the procedures adopted to calibrate the detector and reconstruct the shower direction. Results concerning many shower features as the angular distribution, the density spectrum, the time profile of the shower front, are found well consistent with the expectation.
53692455
Technical aspects and dark matter searches
A variety of detectors has been proposed for dark matter direct detection, but most of them -- by the fact -- are still at R&D stage. In many cases, it is claimed that the lack of an adequate detectors' radio-purity might be compensated through heavy uses of MonteCarlo simulations, subtractions and handlings of the measured counting rates, in order to claim higher sensitivity (just for a particular scenario). The relevance of a correct evaluation of systematic effects in the use of MonteCarlo simulations at very low energy (which has always been safely discouraged in the field so far) and of multiple subtractions and handling procedures applied to the measured counting rate is shortly addressed here at some extent. Many other aspects would also deserve suitably deep investigations.
123403021
Direct detection of dark-matter particles
In this conference the model-independent result on the presence of dark-matter paticles in the galactic halo obtained over seven annual cycles by the 100kg highly radiopure NaI(T1) DAMA/NaI has been presented and several corollary investigations have also been discussed. More recently the model-independent result obtaind over the first four annual cycles by the second generation 250kg highly radiopure NaI(T1) DAMA/LIBRA set-up at the Gran Sasso National Laboratory of the INFN has also been released. Both the experiments have the unique feature to effectively investigate the presence of dark-matter particles in the galactic halo by exploiting the model-independent annual modulation signature. The data collected by the two experiments over elevn annual cycles for a total exposure of 0.82ton x y have pointed out at 8.2 sigma CL a positive result; several corollary model-dependent quests for the candidate particle(s) and related astrophysical, nuclear and particle physics scenarios are under updating. The future experimental activity can give rise to many new interesting results.
121671681
Particle dark matter signal in DAMA/LIBRA
The DAMA/LIBRA experiment, running at LNGS, has a sensitive mass of about 250 kg highly radiopure NaI(TI) and it is mainly devoted to the investigation of Dark Matter (DM) particles in the Galactic halo by exploiting the model independent DM annual modulation signature. The present DAMA/LIBRA experiment and the former DAMA/NaI one have released so far results corresponding to a total exposure of 1.17 ton x yr over 13 annual cycles. They provide a model independent evidence of the presence of DM particles in the galactic halo at 8.9 sigma C.L. (C) 2011 Elsevier B.V. All rights reserved.
53679369
Particle Dark Matter in DAMA/LIBRA
The present DAMA/LIBRA experiment and the former DAMA/NaI have cumulatively released so far the results obtained with the data collected over 13 annual cycles (total exposure: 1.17 ton $\times$ yr). They give a model independent evidence of the presence of DM particles in the galactic halo on the basis of the DM annual modulation signature at 8.9 $\sigma$ C.L. for the cumulative exposure.
120411476
Measurement of the ratio of C3+ and O4+ ions produced by ECRIS to prepare a laser cooling experiment at storage rings
Abstract To prepare the upcoming laser cooling of relativistic C 3+ ion beams at the experimental Cooler Storage Ring (CSRe), a novel experiment was performed using a reaction microscope to determine the ratio of C 3+ ions in mixed ion beams of C 3+ and O 4+ that are produced by an Electron Cyclotron Resonance Ion Source (ECRIS). The mixed ion beams at an energy of 4 keV/u were directed to collide on a supersonic helium gas target. Using the single-electron capture channel and the coincidence technique, the fractions of C 3+ and O 4+ ions in the primary beam were obtained. Using different injection gases for ECRIS, including O 2 , CO, CO 2 , and CH 4 , at a fixed radio-frequency power of 300 W, the measured results showed that the fraction of C 3+ ions was greater than 70% for the injection gases of CO and CO 2 . These measured results are very important and helpful for the upcoming laser cooling experiments.