A tool for calculation of <sup>7</sup>Li(p,n)<sup>7</sup>Be neutron source spectra below the three-body break-up reaction threshold

Pachuau, Rebecca; Lalremruata, B.; Otuka, Naohiko; Hlondo, L. R.; Punte, L. R. M.; Thanga, H. H.

doi:10.1051/epjconf/201714612016

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…This became especially noticable for the second neutron production channel, which seems to be implemented incorrectly in the PINO code. This was already noticed by Pachuau et al [53]. Since the data for this reaction channel is scarce, a designated measurement campaign for the second neutron production channel could be helpful.…”

Section: Investigation Of the 7 Li(pn) 7 Be Neutron Fieldsmentioning

confidence: 71%

“…For the bin per bin comparison heat maps of the measurement, simulation and the difference ratio are shown in Figure 3. 53. The difference ratio shows each measured spectrum covers a narrower energy range than predicted.…”

Section: Comparison Of the 7 Li(pn) 7 Be Neutron Fieldsmentioning

confidence: 87%

“…Simulations utilizing the PINO code [57] suggest a possible recreation of quasi-stellar neutron spectra at different energies relying on a linear combination of neutron spectra, obtained at different proton energies. While previous studies by Ratinsky et al, Feinberg et al and Lederer et al show a good agreement of the simulations at proton energies of E p = 1912 keV [56,31,44], recent studies by Pachuau et al show large deviations between measurement and simulations using the PINO code at energies E p = 3500 keV [53]. These deviations implicate a possible incorrect simulation at proton energies higher than E p = 1912 keV.…”

Section: Aim Of the Thesismentioning

confidence: 92%

“…However, recent studies by Pachuau et al, who compared the PINO code with measurements at proton energies of E p = 3500 keV, show large differences between measurement and simulations [53]. In order to validate the PINO simulations at different proton energies the code needed to be tested between E p = 1880 and 2800 keV.…”

Section: Be Neutron Fieldsmentioning

confidence: 99%

“…For proton energies, where the center of mass velocity of the compound nucleus 8 Be * exceeds the velocity of the emitted neutron, neutrons are emitted in a well defined cone of a specific opening angle θ. For proton energies above approximately 1940 keV, the cone opening half angle becomes θ/2 = 180 • [56,31,44,53]. For the determination of the angle-integrated neutron spectra covering the entire solid angle, neutron spectra would have to be measured between 0 • and 180 • , which leads to several difficulties.…”

Section: Neutron Fieldsmentioning

confidence: 99%

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7Li(p,n)7Be neutron fields and their application for astrophysics

Brückner¹

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Most elements heavier than iron are synthesized in stars during neutron capture reactions in the r- and s-process. The s-process nucleosynthesis is composed of the main and weak component. While the s-process is considered to be well understood, further investigations using nucleosynthesis simulations rely on measured neutron capture cross sections as crucial input parameters. Neutron capture cross sections relevant for the s-process can be measured using various experimental methods. A prominent example is the activation method relying on the 7Li(p,n)7Be reaction as a neutron source, which has the advantage of high neutron intensities and is able to create a quasi-stellar neutron spectrum at kBT = 25 keV. Other neutron sources able to provide quasi-stellar spectra at different energies suffer from lower neutron intensities. Simulations using the PINO tool suggest the neutron activation of samples with different neutron spectra, provided by the 7Li(p,n)7Be reaction, and a subsequent linear combination of the obtained spectrum-averaged cross sections to determine the Maxwellian-averaged cross section (MACS) at various energies of astrophysical relevance. To investigate the accuracy of the PINO tool at proton energies between the neutron emission threshold at Ep = 1880.4 keV and 2800 keV, measurements of the 7Li(p,n)7Be neutron fields are presented, which were carried out at the PTB Ion Accelerator Facility at the Physikalisch-Technische Bundesanstalt in Braunschweig. The neutron fields of ten different proton energies were measured. The presented neutron fields show a good agreement at proton energies Ep = 1887, 1897, 1907, 1912 and 2100 keV. For the other proton energies, E p = 2000, 2200, 2300, 2500, and 2800 keV, differences between measurement and simulation were found and discussed. The obtained results can be used to benchmark and adapt the PINO tool and provide crucial information for further improvement of the neutron activation method for astrophysics. An application for the 7Li(p,n)7Be neutron fields is presented as an activation experiment campaign of gallium, an element that is mostly produced during the weak s-process in massive stars. The available cross section data for the 69,71Ga(n,γ) reactions, mostly determined by activation measurements, show differences up toa factor of three. To improve the data situation, activation measurements were carried out using the 7Li(p,n)7Be reaction. The neutron capture cross sections for a quasi-stellar neutron spectrum at kBT = 25 keV were determined for 69Ga and 71Ga.

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Section: Investigation Of the 7 Li(pn) 7 Be Neutron Fieldsmentioning

confidence: 71%

Section: Comparison Of the 7 Li(pn) 7 Be Neutron Fieldsmentioning

confidence: 87%