Search results for "p-process"
showing 10 items of 35 documents
Isomeric state of $^{80}$Y and its role in the astrophysical rp-process
2001
5 pages, 7 figures.-- PACS nrs: 21.10.Tg; 23.20.Nx; 27.50.+e.
Structure of distributions generated by the scenery flow
2015
We expand the ergodic theory developed by Furstenberg and Hochman on dynamical systems that are obtained from magnifications of measures. We prove that any fractal distribution in the sense of Hochman is generated by a uniformly scaling measure, which provides a converse to a regularity theorem on the structure of distributions generated by the scenery flow. We further show that the collection of fractal distributions is closed under the weak topology and, moreover, is a Poulsen simplex, that is, extremal points are dense. We apply these to show that a Baire generic measure is as far as possible from being uniformly scaling: at almost all points, it has all fractal distributions as tangent …
Experimental study of the 15O(2p, γ)17Ne cross section by Coulomb Dissociation for the rp process
2016
6th Nuclear Physics in Astrophysics Conference (NPA), Lisbon, Portugal, 19 May 2013 - 24 May 2013; Journal of physics / Conference Series 665, 012046 (2016). doi:10.1088/1742-6596/665/1/012046
Mass Measurements with the CSS2 and CIME cyclotrons at GANIL
2005
Commune avec ACEN; This paper presents two original direct mass-measurement techniques developed at GANIL using the CSS2 and CIME cyclotrons as high-resolution mass spectrometers. The mass measurement with the CSS2 cyclotron is based on a time-of-flight method along the spiral trajectory of the ions inside the cyclotron. The atomic mass excesses of 68Se and 80Y recently measured with this technique are -53.958(246) MeV and -60.971(180) MeV, respectively. The new mass-measurement technique with the CIME cyclotron is based on the sweep of the acceleration radio-frequency of the cyclotron. Tests with stable beams have been performed in order to study the accuracy of this new mass-measurement m…
Isomeric state of 80Y and its role in the rp-process
2003
The HIGISOL facility has been used to investigate carefully the isomeric transition 228.5 keV in 80Y. We have measured the electron internal conversion coefficient for this transition αK = 0.50 ± 0.07 which gives the value for half-life of “bare” isomeric state T 1/2 = 6.8 ± 0.5 s. The isomeric state should play an important role in the rp-process calculations.
Phytolith analyses from Khil and Kaf Taht el-Ghar (Western Maghreb): Plant use trajectories in a long-term perspective
2021
In this paper we present the results of phytolith investigations at two archaeological sites in northwestern Morocco: Khil (Tangier) and Kaf Taht el-Ghar (Tétouan). The two sites located in Western Maghreb, one on the Atlantic and one on the Mediterranean coast, were investigated in the framework of the AGRIWESTMED project. Phytolith analysis complemented archaeobotanical, geoarchaeological and archaeological investigations to better identify plant use during the entire occupation sequence. At Khil 16 samples have been studied, coming from two profiles excavated in two different caves of the same system – grotte B and grotte C – that span a chronology comprised between the early Neolithic a…
Proton decay of 108I and its significance for the termination of the astrophysical rp-process
2019
Abstract Employing the Argonne Fragment Mass Analyzer and the implantation-decay-decay correlation technique, a weak 0.50(21)% proton decay branch was identified in 108I for the first time. The 108I proton-decay width is consistent with a hindered l = 2 emission, suggesting a d 5 2 origin. Using the extracted 108I proton-decay Q value of 597(13) keV, and the Q α values of the 108I and 107Te isotopes, a proton-decay Q value of 510(20) keV for 104Sb was deduced. Similarly to the 112,113Cs proton-emitter pair, the Q p ( I 108 ) value is lower than that for the less-exotic neighbor 109I, possibly due to enhanced proton-neutron interactions in N ≈ Z nuclei. In contrast, the present Q p ( Sb 104 …
Nuclear structure theory for the astrophysical rp-process and r-process
2003
Abstract The astrophysical processes of rapid-proton capture and rapid-neutron capture require the knowledge of many nuclear properties which are not known from experiment. I will describe two examples of how theoretical models are used to provide this input. The first of these uses the Hartree-Fock method for displacement energies to obtain the masses of proton-rich nuclei needed for the rp-process. The second uses a model for configuration mixing near 132 Sn to provide Q values and beta-decay lifetimes for the r-process.
Systematic measurements of proton- and alpha-capture cross sections relevant to the modelling of the p process
2005
Several in-beam cross section measurements of proton- as well as α -capture reactions in the Se-Sb region have been carried out to obtain global input parameters for Hauser-Feshbach (HF) calculations. In total, 20 (p, γ ) and 7 ( α , γ ) reactions were measured. We compare some of these results with Hauser-Feshbach calculations using various optical model potentials and nuclear level densities.
New experimental efforts along the rp-process path
2007
The level structure just above the proton threshold of the nucleus 30S has been studied using the neutron removal process on fast radioactive beams at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. In this work we provide a description of the experimental setup. The present status of the analysis is also discussed.