Abstract
With the much-anticipated multi-petawatt (PW) laser facilities that are coming online, neutron sources with extreme fluxes could soon be in reach. Such sources would rely on spallation by protons accelerated by the high-intensity lasers. These high neutron fluxes would make possible not only direct measurements of neutron capture and β-decay rates related to the r-process of nucleosynthesis of heavy elements, but also such nuclear measurements in a hot plasma environment, which would be beneficial for s-process investigations in astrophysically relevant conditions. This could, in turn, finally allow possible reconciliation of the observed element abundances in stars and those derived from simulations, which at present show large discrepancies. Here, we review a possible pathway to reach unprecedented neutron fluxes using multi-PW lasers, as well as strategies to perform measurements to investigate the r- and s-processes of nucleosynthesis of heavy elements in cold matter, as well as in a hot plasma environment.
Highlights
STATEMENT OF THE PROBLEMThe overall picture of the production of the hadronic elements around us, starting with primordial hydrogen, is quite clear:1 fusion of light elements up to and including iron, and various nucleosynthesis processes to form heavier elements
These high neutron fluxes would make possible direct measurements of neutron capture and β-decay rates related to the r-process of nucleosynthesis of heavy elements, and such nuclear measurements in a hot plasma environment, which would be beneficial for s-process investigations in astrophysically relevant conditions
We have here outlined a strategy that would open a pathway, using upcoming multi-PW laser facilities, for laboratory investigations of the s- and r-processes, including direct measurements of doubleneutron capture events and measurements in hot plasmas in order to go toward astrophysically relevant measurements
Summary
The overall picture of the production of the hadronic elements around us, starting with primordial hydrogen, is quite clear: fusion of light elements up to and including iron, and various nucleosynthesis processes to form heavier elements. The s-process takes place in stars over millions of years (Fig. 2) and has been repeatedly tested in the laboratory using accelerators and reactors.2–4 This type of nucleosynthesis ceases to be effective at the quasi-stable element 209Bi, because following a further neutron capture and a β decay, 210Po is subject to α decay, reducing the mass number A and limiting further growth of the nucleus. Compared with the existing facilities described above, new players are emerging, namely ultra-high-power (multi-petawatt, PW) lasers, which could provide a sharp increase in the neutron fluxes available This would allow direct measurements of the rprocess, as well as the s-process, in heavy elements. It is the aim of the present paper to describe these new developments
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