B. Indirect methods
B.1. Beta-delayed proton decay
The resonant capture of protons is a two-step process where the proton incident on a nucleus populates first a metastable state in the
compound nucleus (1st step) that then de-excites (2nd step) by gamma-ray emission. The corresponding astrophysical reaction rates are
given by the properties of the narrow, isolated resonances only: spin and parity, energy and resonant strength ωγ. To study these
resonances at astrophysical energies by direct measurements is not always easy or even possible. An alternative is to populate the
same metastable states and determine their spectroscopic properties by other means. One way is the decay spectroscopy: we chose an
exotic nucleus that will beta-decay to these same states. These are schematically illustrated in Figure 4.
We have studied β-delayed proton decay (βp) at Texas A&M University using ASTROBOX2, an improved version of and early gas detector ASTROBOX-1,
both developed with TAMU and CEA/IRFU Saclay. A clone of this new detector is being worked on at IFIN-HH, for use in European laboratories ASTROBOX2E.
B.2. The breakup of 9C
In 2001 we proposed to use nuclear breakup data to determine the ANC (Asymptotic Normalization Coefficients) for the breakup of
nuclei Y->X+p and from there to evaluate the astrophysical S-factors for radiative proton capture reactions X(p,g)Y. Important
NA reactions data like S17 [5,6] and S18  were evaluated using data from literature. Later a dedicated experiment at GANIL was
used to obtain NA data for the reactions 22Mg(p,γ)23Al  and 23Al(p,γ)24Si .
In proposal NP1412-SAMURAI29R1 approved by the PAC of RIBF at RIKEN, Wako, Japan, we use the same scheme: the breakup of 9C at
300 MeV/nucleon to evaluate the astrophysical S-factor for radiative proton capture on 8B. The experiment is part of a group of
four approved proton breakup measurements and scheduled, tentatively, in the fall of 2017.
B.3. Trojan Horse Method measurements
Trojan Horse Method was introduced and demonstrated as a valuable method for NA by the group of prof. Claudio Spitaleri from the University
of Catania and INFN LNS. They have proposed and test measurements were done in collaboration in Bucharest, at the 9 MV FN tandem accelerator
together with us to check if the reaction 12C + 12C can be studied using the Trojan Horse Method. The reaction proposed
was 12C(16O,α20Ne)α. The test was done using an 16O beam on 12C targets, but the answer was NO, the method cannot be used for this
B.4. Optical Model Potentials for nucleus-nucleus collisions
We have a long-term program to understand and describe nucleus-nucleus collisions in terms of one interaction potential, the optical model potential (OMP).
LT has worked on the problem for almost two decades with dr. F. Carstoiu. The motivation is that a good understanding of all phenomena
occurring in the elastic nucleus-nucleus scattering, which are used typically to extract OMP, and the interpretation of the origin of
different aspects, including the well know potential ambiguities, are of crucial importance for finding and justifying the procedures
used for predicting nucleus-nucleus OMP in the era of radioactive nuclear beams (RNB) (see ours based on double folding in Ref. 10).
The reliability of these potentials is crucial in the correct description of a number of reactions, from elastic to transfer, to
breakup, at energies ranging from a few to a few hundred MeV/nucleon. Of particular interest for us is to support the absolute
values of the calculated cross sections for reactions used in indirect methods for nuclear astrophysics, see references [11,12]
for the most recent results.
 Daniela Chesneanu, L. Trache, R. Margineanu, A. Pantelica, D. Ghita, M. Straticiuc, I. Burducea, A. M. Blebea-Apostu, C. M. Gomoiu, and X. Tang, AIP Conference Proceedings 1645, 311 (2015).
 I. Burducea, M. Straticiuc, D.G. Ghita, D.V. Mosu, C.I. Calinescu, N.C. Podaru, D.J.W. Mous, I. Ursu, N.V. Zamfir, Nuclear Instruments and Methods in Physics Research B 359, 1219, 2015.
 R. M. Margineanu, C. Simion, S. Bercea, O.G. Duliu, D. Gheorghiu, A. Stochioiu and M. Matei, Appl. Radiat. Isot. 66, 1501 (2008).
 D. Tudor, A.I. Chilug, M. Straticiuc, L. Trache et al., in C. Spitaleri, L. Lamia and G.R. Pizzone (eds.), Proceedings of the 8th European Summer School of Physics on Experimental Nuclear Astrophysics (Santa Tecla School), J. of Phys: Conf Series, vol. 703 (2016) 012028.
 L. Trache, F. Carstoiu, C.A. Gagliardi and R.E. Tribble, Phys. Rev. Lett. 87, 271102 (2001).
 L. Trache, F. Carstoiu, CA Gagliardi and RE Tribble, Phys. Rev. C 69, 032802 (2004).
 L. Trache, F. Carstoiu, CA Gagliardi and RE Tribble, Phys. Rev. C 66, 035801 (2002).
 A. Banu et al., Phys. Rev. C 84, 015803.
 A. Banu et al., Phys. Rev. C 86, 015806
 L. Trache et al. Phys. Rev. C 61, 024612 (2000).
 T. Al-Abdullah, F. Carstoiu, X. Chen, H. L. Clark, C. A. Gagliardi, Y.-W. Lui, A. Mukhamedzhanov, G. Tabacaru, Y. Tokimoto, L. Trache, R. E. Tribble, and Y. Zhai, Phys. Rev. C 89, 025809 (2014).
 T. Al-Abdullah, F. Carstoiu, C. A. Gagliardi, G. Tabacaru, L. Trache, and R. E. Tribble, Phys. Rev. C 89, 064602 (2014).
Carpathian Summer Schools of Physics
NAG was also instrumental in the organization of the most recent editions of the Carpathian Summer Schools of Physics, a tradition
that begun in 1964. Six out of the 7 latest editions were a series dedicated to nuclear and particle astrophysics, in relation to
nuclei and to physics of exotic nuclei in particular. The Carpathian school is part of the European Network of Nuclear Astrophysics
Schools (ENNAS), together with the European Summer School on Experimental Nuclear Astrophysics, ESSENA (Santa Tecla, Italy) and the
Russbach School on Nuclear Astrophysics, RSNA (Russbach am Pass Gschütt, Austria). In agreement with those schools’ organizers, we
created an established network of periodic events that responds to the need of preparing and educating the younger generations of
physicists in the cross disciplinary fields of nuclear physics and astrophysics.
Below are links to the latest editions of CSSP:
CSSP 2012 , CSSP 2014, CSSP 2016
|Group leader: Dr. Livius Trache
Senior Researcher 1
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|Dr. Florin Carstoiu|
Senior Researcher 1 (Department of Theoretical Physics)
The collaboration with dr. Carstoiu, which lasts for over 20 years, continued. LT and dr. Carstoiu
continued working together on subjects from NA or on related projects. Of prime and immediate concern was to finalize
by publication work which was done earlier, either at Texas A&M University or elsewhere. This resulted in 7 papers in 2013-2016.
| || || |
|PhD Student Alexandra Chilug
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|PhD Student Dana Tudor
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|Ionut Catalin Stefanescu, MS
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