•Determination of the differential cross-sections for the measured 3He+3H nuclear reaction, which has three decaying channels.•First cross-section measurements with 3He beam energy up to 3.3 MeV for ...two decay channels 3H(3He,d)4He and 3H(3He,p)5He.•Measured angular dependence for the two decay channels.•Utilization of special ΔE–E telescope detector to distinguish between the different decay channels.•Establishment of 3He nuclear reaction ion beam technique for non-destructive tritium depth profiling in solids.
The differential cross-section for the 3He+3H nuclear reaction was measured in a thin tritiated PdTi film that was deposited on a Si wafer. The sample was loaded with 3H2 gas at a temperature of 300 °C and at a pressure of 1.8 bar. The total activity of the sample, measured by the liquid scintillation technique, was found to be 395 MBq. Two peaks were observed in the spectrum of the thick Si detector, corresponding to the 3H(3He,d)4He and 3H(3He,p)5He reaction channels. The differential cross-section was determined for the energy range of the 3He beam from 0.6 to 3.4 MeV, at three scattering angles of 125, 135 and 155°. The differential cross-section for the first channel remained almost constant within the measured energy range, while the cross-section for the second channel increased with energy. In both cases, the cross-sections reached their maximum value at the lowest scattering angle measured. The differential cross-sections were verified using a thick solid tritiated tungsten target. For assessing the tritium depth profile, only the reaction channel 3H(3He,d)4He can be utilized.
The observation of neutrinos emitted in the p − p chain and in the CNO cycle can be employed to test the Standard Solar Model. The 3He(α,γ)7Be reaction is the first reaction of the 2nd and 3rd branch ...of the p − p chain, so the indetermination of its cross section significantly affects the predicted 7Be and 8B neutrino fluxes. Notwithstanding its relevance and the great deal of experimental and theoretical papers, information of the reaction cross section at energies of the core of the Sun (15 keV - 30 keV) is sparse and additional experimental work is necessary to attain the target (~ 3%) accuracy. The precise understanding of the external capture component to the 3He(α,γ)7Be reaction cross section is pivotal for the theoretical assessment of the reaction mechanism. In this work, the indirect measurement of this external capture component using the Asymptotic Normalization Coefficient (ANC) technique is discussed. To extract the ANC, the angular distributions of deuterons yielded in the 6Li(3He,d)7Be α-transfer reaction were detected with high precision at E3He=3.0 MeV and 5.0 MeV. The ANCs were then deduced from the juxtaposition of DWBA and CC calculations with the experimental angular distributions and the zero energy astrophysical S-factor for 3He(α,γ)7Be reaction was calculated to equal 0.534 ± 0.025 keVb. Both our experimental and theoretical approaches were tested through the analysis of the 6Li(p,γ)7Be astrophysical factor, with further interesting astrophysical implications.
The detection of the neutrinos produced in the p−p chain and in the CNO cycle can be used to test the Standard Solar Model. The 3He(α,γ)7Be reaction is the first reaction of the 2nd and 3rd branch of ...the p−p chain, therefore, the uncertainty of its cross section sensitively influences the prediction of the 7Be and 8B neutrino fluxes. Despite its importance and the large number of experimental and theoretical works devoted to this reaction, the knowledge on the reaction cross section at energies characterizing the core of the Sun (15 keV - 30 keV) is limited and further experimental efforts are needed to reach the desired (≈ 3%) accuracy. The precise knowledge on the external capture contribution to the 3He(α,γ)7Be reaction cross section is crucial for the theoretical description of the reaction mechanism. In the present work the indirect measurement of this external capture contribution using the Asymptotic Normalization Coefficient (ANC) technique is reported. To extract the ANC, the angular distributions of deuterons emitted in the 6Li(3He,d)7Be α-transfer reaction were measured with high precision at EH3e = 3.0 MeV and EH3e = 5.0 MeV. The ANCs were then extracted from comparison of DWBA calculations to the measured data and the zero energy astrophysical S-factor for 3He(α,γ)7Be reaction was found to be 0.534 ± 0.025 keVb.
For the first time in an application to nuclear astrophysics, a process induced by the unstable
5
He = (
4
He-n) nucleus, the
3
He+
5
He
→
2
α
reaction, has been studied through the Trojan Horse ...Method (THM). For that purpose, the quasi-free (QF) contribution of the
9
Be(
3
He,
α
α
)
4
He reaction was selected at
E
3
He
=
4
MeV incident energy. The reaction was studied in a kinematically complete experiment following a recent publication (Spitaleri et al. in Eur Phys J A 56:18, 2020), where for the quasi free contribution the momentum distribution between
α
and
5
He particle cluster in the
9
Be nucleus in the ground state have been extracted. The angular distribution of the QF
3
He+
5
He
→
2
α
reaction was measured at
θ
cm
= 78
∘
–115
∘
. The energy dependence of the differential cross section of the
3
He+
5
He
→
2
α
virtual reaction was extracted in the energy range
E
cm
= 0–650 keV. The total cross section obtained from the Trojan-horse method was normalized to absolute cross sections from a theoretical calculation in the energy range
E
cm
=300–620 keV.
•Production of stable tritiated sample.•Detection of reaction products from nuclear reaction between tritium and 3-helium.•Establishment of a new nuclear reaction analyzing method for tritium ...detection via 3-helium beam.•Review of the existing literature on the nuclear reaction between 3He and 3H.
A solid thick tritiated W sample was produced in order to probe the efficiency of detecting tritium via 3He ion beam using nuclear reactions analysis (NRA). Extensive literature search showed that there were only a few measurements done more than sixty years ago using the reaction with 3He. Their aim was mainly to measure the absolute cross section of the reaction. In order to use this reaction as an analysing tool for low level radioactive waste we need the differential cross section at certain angles. Using a thick tritiated W sample we measured the NRA signal in the 3He energy range from 0.7 MeV to 5.1 MeV and we have detected reaction products with energies between 6.5 MeV and 9.75 MeV that were not present on a deuterated W sample prepared in the same manner. This NRA signal proved to be due to deuterium and protons coming from the nuclear reaction between tritium and 3He. The detection signal increased with 3He energy up to 3.4 MeV and decreased with energy at the highest beam energies. At higher energies particles from W and target impurities start to disturb the measurement. Their origin might be due to other nuclear reactions, for example between 3He and W or 3He with 13C or 14N.
A new study of the quasi-free contribution to the
3
He
+
9
Be
→
3
α
reaction (
Q
value = 19.004 MeV) at low
E
3
He
energy is presented. The reaction was studied in a kinematically complete experiment ...at beam energy of 4 MeV. To clarify the presence of the quasi-free mechanism, the
4
He
–
5
He
momentum distribution of the
9
Be
ground state was extracted. Standard tests were also carried out to confirm the presence of the quasi-free contribution and are reported in this work. The full width at half maximum of the
4
He
–
5
He
inter-cluster momentum distribution inside
9
Be
was measured with improved accuracy, by adopting several different approaches that all led to consistent results. These preliminary investigations on the reaction mechanism are fundamental for future studies employing the Trojan Horse Method, with the
5
He
unbound nucleus as a virtual projectile.
.
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.
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