.
The
10
B(p,
α
1
)
7
Be reaction has been studied for the first time via the Trojan Horse Method (THM) applied to the
2
H(
10
B,
α
7
Be)n quasi-free three-body process. The present experiment ...allowed for a clear separation between
α
0
and
α
1
channels thanks to the improved energy resolution with respect to previous THM studies of the
2
H(
10
B,
α
7
Be)n reaction. The extracted half-off-energy-shell cross section was found to be characterized by several structures attributable to the population of
11
C. In particular, six resonances have been observed at 10.086, 10.352, 10.525, 10.686, 10.841 and 10.976 MeV
11
C excitation energy.
Electron screening in palladium Cvetinović, A.; Đeorđić, D.; Guardo, G.L. ...
Physics letters. B,
03/2023, Letnik:
838
Journal Article
Recenzirano
Odprti dostop
The electron screening effect was studied in the 1H(7Li,α)4He, 1H(19F,αγ)16O and 2H(19F,p)20F nuclear reactions on two different hydrogen-containing palladium foils. In one of the targets we did not ...detect a large enhancement of the cross section due to electron screening, and in the second one we measured a high electron screening potential for all three reactions, up to an order of magnitude above the theoretical models. Contrary to the predictions given by the available theories, the data suggest that the reason behind this difference is linked to a dependence of the electron screening potential on the host's crystal lattice structure and the location of the target nuclei in the metallic lattice.
Abstract
The
$$^{27}\hbox {Al}(\hbox {p},\alpha )^{24}\hbox {Mg}$$
27
Al
(
p
,
α
)
24
Mg
reaction, which drives the destruction of
$$^{27}$$
27
Al and the production of
$$^{24}\hbox {Mg}$$
24
Mg
in ...stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM), by measuring the
$$^2\hbox {H}(^{27}\hbox {Al},\alpha ^{24}\hbox {Mg})\hbox {n}$$
2
H
(
27
Al
,
α
24
Mg
)
n
three-body reaction. The experiment covered a broad energy range (
$$E_\mathrm{c.m.}\le \,1.5\,\hbox {MeV}$$
E
c
.
m
.
≤
1.5
MeV
), aiming to investigate those of interest for astrophysics. The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydrogen burning (70–120 keV), with potential impact on astrophysics. To estimate such an impact a second run of the experiment is needed, since the background due the three-body reaction hampered to collect enough data to resolve the resonant structures and extract the reaction rate.
Proper selection of the quasi-free (QF) break-up channel in a three-body reaction is a key aspect for the applicability of the Trojan Horse Method (THM). The Treiman-Yang (TY) Criterion is a ...model-independent experimental test for the dominance of the QF mechanism, and hence constitutes one of the strongest validity tests of the THM. An experiment was performed at LNS to apply the test to the d(
10
B,
7
Be α)n reaction. Here, the criterion is described and some preliminary data from the experiment are shown.
Electron screening in metals Gajevi, J; Lipoglavšek, M; Likar, A ...
Journal of physics. Conference series,
01/2016, Letnik:
665, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In order to further investigate electron screening effect we studied proton induced nuclear reactions over an energy range from 0.8 to 2.6 MeV for different environments: Mn and Cd metals and MnO and ...CdO insulators. Shifts in resonance energy for metallic relative to insulator targets were not observed. No large electron screening could be deduced for (p,γ) and (p,n) reactions in Mn. Moreover, no large electron screening can be deduced with certainty for the (p,n) reaction in Cd.
The
27
Al
(
p
,
α
)
24
Mg
reaction, which drives the destruction of
27
Al and the production of
24
Mg
in stellar hydrogen burning, has been investigated via the Trojan Horse Method (THM), by ...measuring the
2
H
(
27
Al
,
α
24
Mg
)
n
three-body reaction. The experiment covered a broad energy range (
E
c
.
m
.
≤
1.5
MeV
), aiming to investigate those of interest for astrophysics. The results confirm the THM as a valuable technique for the experimental study of fusion reactions at very low energies and suggest the presence of a rich pattern of resonances in the energy region close to the Gamow window of stellar hydrogen burning (70–120 keV), with potential impact on astrophysics. To estimate such an impact a second run of the experiment is needed, since the background due the three-body reaction hampered to collect enough data to resolve the resonant structures and extract the reaction rate.
The dependence of electron screening potential on the position of the target nucleus in host-material lattice was investigated by measuring the rate of the 2H(19F,p)20F reaction in zirconium, ...titanium and palladium targets containing deuterium. Very different values of the screening potential were measured, thus showing the link with the valence electron densities around deuterium nuclei.
The 10B(p,α0)7Be reaction has been studied by applying the Trojan Horse method to the 2H(10B,α0 7Be)n reaction. The bare-nucleus astrophysical S(E)-factor in absolute units was extracted in a wide ...energy range, from 2.2 MeV to 3 keV and normalized to the direct experimental data, thus allowing determination of the electron screening potential for which a value of Ue=391±74 eV was obtained.
The 10B(p,α0)7Be reaction cross section has been measured in an wide energy range from 2.2 MeV down to 3 keV in a single experiment applying THM. Optimized experimental set-up ensured good energy ...resolution leading to a good separation of α0 and α1 contributions to the cross section coming from the 7Be ground and first excited state, respectively.
Abstract
The dependence of electron screening potential on the position of the target nucleus in host-material lattice was investigated by measuring the rate of the
2
H(
19
F,p)
20
F reaction in ...zirconium, titanium and palladium targets containing deuterium. Very different values of the screening potential were measured, thus showing the link with the valence electron densities around deuterium nuclei.
PDF
