6533b823fe1ef96bd127f953

RESEARCH PRODUCT

Mass measurements for explosive nucleosynthesis in stars

subject

description

Atomic masses of almost 50 neutron-deficient isotopes in the region of tin and below were measured with the high-precision mass spectrometer JYFLTRAP Penning trap setup at the IGISOL facility in Jyv¨askyl¨a. The masses have a direct impact on the nucleosynthesis modelling of neutron-deficient isotopes and were used for rp- and p-process model calculations. For example, the abundance of stable molybdenum and ruthenium isotopes can not be explained with present knowledge. The rp process has been predicted to end in the SnSbTecycle. The new mass measurements do not allow a strong SnSbTe-cycle to be formed. A carbon-cluster ion source based on laser ablation has been constructed. The source was used for investigating systematic effects of the JYFLTRAP setup. The mass-dependent effect and a residual uncertainty of the system were quantified. The obtained values were m(r)=r = (7:8 0:3 10��10=u) m for mass dependence and res(r)=r = 1:2 10��8 for the residual uncertainty. If the mass difference range between the reference ion and ion of interest is restricted to 24, the values are m;lim(r)=r = (7:5 0:4 10��10=u) m and res;lim(r)=r = 7:9 10��9, respectively. The JYFLTRAP setup was used to survey the production of neutron-deficient nuclides with proton- and 3He-induced fusion evaporation reactions. The measured proton-induced relative yields were compared to a statistical model calculation. The survey will help to plan future mass and spectroscopy measurements in the region.Atomic masses of almost 50 neutron-deficient isotopes in the region of tin and below were measured with the high-precision mass spectrometer JYFLTRAP Penning trap setup at the IGISOL facility in Jyv¨askyl¨a. The masses have a direct impact on the nucleosynthesis modelling of neutron-deficient isotopes and were used for rp- and p-process model calculations. For example, the abundance of stable molybdenum and ruthenium isotopes can not be explained with present knowledge. The rp process has been predicted to end in the SnSbTecycle. The new mass measurements do not allow a strong SnSbTe-cycle to be formed. A carbon-cluster ion source based on laser ablation has been constructed. The source was used for investigating systematic effects of the JYFLTRAP setup. The mass-dependent effect and a residual uncertainty of the system were quantified. The obtained values were m(r)=r = (7:8 0:3 10��10=u) m for mass dependence and res(r)=r = 1:2 10��8 for the residual uncertainty. If the mass difference range between the reference ion and ion of interest is restricted to 24, the values are m;lim(r)=r = (7:5 0:4 10��10=u) m and res;lim(r)=r = 7:9 10��9, respectively. The JYFLTRAP setup was used to survey the production of neutron-deficient nuclides with proton- and 3He-induced fusion evaporation reactions. The measured proton-induced relative yields were compared to a statistical model calculation. The survey will help to plan future mass and spectroscopy measurements in the region.