Sep 4 – 9, 2022
Europe/Zurich timezone

Investigation of the $^7$Li(p,n)$^7$Be neutron fields at high energies

Sep 6, 2022, 6:00 PM
61/1-201 - Pas perdus - Not a meeting room - (CERN)

61/1-201 - Pas perdus - Not a meeting room -


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Benjamin Brueckner (Goethe University Frankfurt)


The neutron activation method is well-suited to investigate neutron-capture
cross sections relevant for the main s-process component. Neutrons can be pro-
duced via the $^7$Li(p,n) reaction with proton energies of 1912 keV at e.g. Van de
Graaf accelerators, which results in a Maxwellian spectrum of neutrons corre-
sponding to a temperature of k$_\text{B}$T = 25 keV. This mimicks the s-process scenario
in low-mass asymptotic giant branch (AGB) stars. However, the weak s-process
takes place in massive stars at temperatures between 25 and 90 keV. Neutron
spectra corresponding to a Maxwell-Boltzmann distribution with k$_\text{B}$T > 25 keV
cannot be produced by the $^7$Li(p,n) reaction. Simulations using the PINO [1]
code suggest that a Maxwellian spectrum for higher energies can be produced
by a linear combination of different neutron spectra. The resulting spectrum
averaged cross sections can be combined to e.g. k$_\text{B}$T = 90 keV Maxwellian Av-
eraged Cross Section (MACS). To validate the PINO code at proton energies
E$_{\text{p}}$ $\neq$ 1912 keV, measurements were carried out at the PTB Ion Accelerator
Facility (PIAF) at the Physikalisch-Technische Bundesanstalt in Braunschweig,
Germany. The neutron fields were measured using a pulsed proton beam and
three 6Li-glass scintillation detectors mounted at different angles. The neutron
energy was determined by time-of-flight (TOF).

[1] R. Reifarth et. al., Nuclear Instruments and Methods in Physics Research
A 608, 139 (2009)

Primary authors

Benjamin Brueckner (Goethe University Frankfurt) Cem Deniz Kurtulgil (Goethe University Frankfurt (DE)) Christoph Langer (FH Aachen, GSI) Kafa Al-Khasawneh (Goethe University Frankfurt) Kathrin Goebel (Goethe University Frankfurt (DE), FAIR) Mario Weigand (Goethe University Frankfurt) Markus Reich (Goethe University Frankfurt) Meiko Volknandt (Goethe University Frankfurt) Michael Wiescher (University of Notre Dame) Philipp Erbacher (Goethe University Frankfurt) Ralf Heinrich Nolte (Physikalisch-Technische Bundesanstalt (DE)) Rene Reifarth (Goethe University Frankfurt (DE)) Tanja Heftrich (Johann-Wolfgang-Goethe Univ. (DE))

Presentation materials