Abstract / Description of output
The detection of long-lived radionuclides through ultra-sensitive single
atom counting via accelerator mass spectrometry (AMS) offers
opportunities for precise measurements of neutron capture cross
sections, e.g. for nuclear astrophysics. The technique represents a
truly complementary approach, completely independent of previous
experimental methods. The potential of this technique is highlighted at
the example of the $^{54}$Fe($n, \gamma$)$^{55}$Fe reaction. Following a
series of irradiations with neutrons from cold and thermal to keV
energies, the produced long-lived $^{55}$Fe nuclei ($t_{1/2}=2.744(9)$
yr) were analyzed at the Vienna Environmental Research Accelerator
(VERA). A reproducibility of about 1% could be achieved for the
detection of $^{55}$Fe, yielding cross section uncertainties of less
than 3%. Thus, the new data can serve as anchor points to time-of-flight
experiments. We report significantly improved neutron capture cross
sections at thermal energy ($\sigma_{th}=2.30\pm0.07$ b) as well as for
a quasi-Maxwellian spectrum of $kT=25$ keV ($\sigma=30.3\pm1.2$ mb) and
for $E_n=481\pm53$ keV ($\sigma= 6.01\pm0.23$ mb). The new experimental
cross sections have been used to deduce improved Maxwellian average
cross sections in the temperature regime of the common $s$-process
scenarios. The astrophysical impact is discussed using stellar models
for low-mass AGB stars.
Original language | English |
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Pages (from-to) | 25808 |
Journal | Physical Review C |
Volume | 96 |
Issue number | 2 |
DOIs | |
Publication status | Published - 28 Aug 2017 |
Keywords / Materials (for Non-textual outputs)
- Nuclear Experiment
- Astrophysics - Solar and Stellar Astrophysics