Penning trap mass measurements of ^{99-109}Cd with the ISOLTRAP mass spectrometer, and implications for the rp process (original) (raw)
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Investigating the rp-process with the Canadian Penning trap mass spectrometer
The European Physical Journal A, 2005
The Canadian Penning trap (CPT) mass spectrometer at the Argonne National Laboratory makes precise mass measurements of nuclides with short half-lives. Since the previous ENAM conference, many significant modifications to the apparatus were implemented to improve both the precision and efficiency of measurement, and now more than 60 radioactive isotopes have been measured with half-lives as short as one second and with a precision (∆m/m) approaching 10 −8. The CPT mass measurement program has concentrated so far on nuclides of importance to astrophysics. In particular, measurements have been obtained of isotopes along the rp-process path, in which energy is released from a series of rapid proton-capture reactions. An X-ray burst is one possible site for the rp-process mechanism which involves the accretion of hydrogen and helium from one star onto the surface of its neutron star binary companion. Mass measurements are required as key inputs to network calculations used to describe the rp-process in terms of the abundances of the nuclides produced, the light-curve profile of the X-ray bursts, and the energy produced. This paper will present the precise mass measurements made along the rp-process path with particular emphasis on the "waiting-point" nuclides 68 Se and 64 Ge. PACS. 21.10.Dr Binding energies and masses-26.30.+k Nucleosynthesis in novae, supernovae, and other explosive environments-26.50.+x Nuclear physics aspects of novae, supernovae, and other explosive environments
2008
The masses of very neutron-deficient nuclides close to the astrophysical rp-and νp-process paths have been determined with the Penning trap facilities JYFLTRAP at JYFL/Jyväskylä and SHIP-TRAP at GSI/Darmstadt. Isotopes from yttrium (Z = 39) to palladium (Z = 46) have been produced in heavy-ion fusion-evaporation reactions. In total 21 nuclides were studied and almost half of the mass values were experimentally determined for the first time: 88 Tc, 90−92 Ru, 92−94 Rh, and 94,95 Pd. For the 95 Pd m , (21/2 + ) high-spin state, a first direct mass determination was performed. Relative mass uncertainties of typically δm/m = 5×10 −8 were obtained. The impact of the new mass values has been studied in νp-process nucleosynthesis calculations. The resulting reaction flow and the final abundances are compared to those obtained with the data of the Atomic Mass Evaluation 2003. PACS numbers: 07.75.+h Mass spectrometers, 21.10.Dr Binding energies and masses, 26.30.-k Nucleosynthesis in novae, supernovae, and other explosive environments, 26.50.+x Nuclear physics aspects of novae, supernovae, and other explosive environments
Approaching the N=82 shell closure with mass measurements of Ag and Cd isotopes
Physical Review C, 2010
Mass measurements of neutron-rich Cd and Ag isotopes were performed with the Penning trap mass spectrometer ISOLTRAP. The masses of 112,[114][115][116][117][118][119][120][121][122][123][124]120,[122][123][124]126,128 Cd, determined with relative uncertainties between 2 × 10 −8 and 2 × 10 −7 , resulted in significant corrections and improvements of the mass surface. In particular, the mass of 124 Ag was previously unknown. In addition, other masses that had to be inferred from Q values of nuclear decays and reactions have now been measured directly. The analysis includes various mass differences, namely the two-neutron separation energies, the applicability of the Garvey-Kelson relations, double differences of masses δV pn , which give empirical proton-neutron interaction strengths, as well as a comparison with recent microscopic calculations. The δV pn results reveal that for even-even nuclides around 132 Sn the trends are similar to those in the 208 Pb region.
Masses along the rp-process path and large scale surveys on Cu, Ni and Ga with ISOLTRAP
Nuclear Physics A, 2004
Mass measurements with exceptionally low uncertainty can be performed with the Penning trap mass spectrometer ISOLTRAP. Out of the large number of recent measurements two regions of the chart of nuclei have been selected for this article. The astrophysically interesting N = Z nuclei above Z = 32 and neutron-rich copper, nickel and gallium isotopes have been investigated. The relative mass uncertainty obtained is generally ≤ 1 • 10 −7 .