123784951
Beta decay of highly charged ions
Ion storage rings and ion traps provide the very first opportunity to address nuclear beta decay under conditions prevailing in hot stellar plasmas during nucleosynthesis, i.e. at high atomic charge states. Experiments are summarized that were performed in this field during the last decade at the ion storage-cooler ring ESR in Darmstadt. Special emphasis is given to the first observation of bound-state beta decay, where the created electron remains bound in an inner orbital of the daughter atom. The impact of this specific ‘stellar’ decay mode for s-process nucleosynthesis as well as for nuclear ‘eon clocks’ is outlined. Finally, a new technique, single-ion decay spectroscopy, is presented, where one observes two-body beta decay characteristics (i.e. orbital electron capture or bound-state beta decay) of highly charged, single ions for well-defined nuclear and atomic quantum states of both the mother – and the daughter – ion.
120649134
YAP:Ce and CsI(Tl) detectors for dielectronic recombination experiment at the CSRm
Abstract The storage ring CSRm in Lanzhou provides good possibilities for electron-ion collision studies with cooled ion beams. To carry on the recombination experiment at the CSRm, a scintillation detector CsI(Tl) to detect the recombined ions was developed and tested. In addition, a YAP:Ce detector has been developed and installed at CSRm and capability of handling a high count rate of ∼107 s−1 has been obtained which is sufficient for the future dielectronic recombination experiment at the CSRm. The comparison of the characteristics of these two detectors is presented.
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.
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.