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1. Cross-section measurements at astrophysically relevant energies: The LUNA experiment

Author

C. G. Bruno, Gianluca Imbriani, Davide Trezzi, C. Gustavino, Carlo Broggini, Gy. Gyürky, G. Gervino, Daniel Bemmerer, A. Di Leva, M. Junker, Tamás Szücs, Paolo Prati, R. Menegazzo, Antonio Caciolli, E. Somorjai, A. Formicola, M. Anders, F. Cavanna, Z. Elekes, Douglas Scott, P. Corvisiero, Rosanna Depalo, Frank Strieder, Oscar Straniero, Marialuisa Aliotta, Zs. Fülöp, A. Guglielmetti, A., Formicola, C. G., Bruno, A., Caciolli, F., Cavanna, R., Depalo, DI LEVA, Antonino, D. A., Scott, D., Trezzi, M., Aliotta, M., Ander, D., Bemmerer, C., Broggini, P., Corvisiero, Z., Eleke, F?l?p, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gy?rky, G. y., Imbriani, Gianluca, M., Junker, R., Menegazzo, P., Prati, E., Somorjai, O., Straniero, F., Strieder, and T., Sz?cs

Subjects
Nuclear and High Energy Physics, S-factor, Underground accelerator, Astrophysics::High Energy Astrophysical Phenomena, Measure (physics), Astrophysics::Cosmology and Extragalactic Astrophysics, Luminosity, Nuclear physics, Nucleosynthesis, Nuclear astrophysics, Astrophysics::Solar and Stellar Astrophysics, underground measurements, Nuclear Astrophysic, Nuclear Experiment, Instrumentation, Astrophysics::Galaxy Astrophysics, Experimental Nuclear Physic, Physics, COSMIC cancer database, Solar fusion, LUNA, Stars, Neutrino, Big Bang nucleosynthesis, Direct cross-section
Abstract

Accurate knowledge of thermonuclear reaction rates is important in understanding the generation of energy, the luminosity of neutrinos, and the synthesis of elements in stars. Cross-section measurements for quiescent stellar H-burning are mainly hampered by extremely low counting rate and cosmic background. The LUNA Collaboration has shown that, by going underground and by using the typical techniques of low background physics, it is possible to measure nuclear cross-sections down to the energy of the nucleosynthesis inside stars. This paper reports an overview of the experimental techniques adopted in underground nuclear astrophysics through a summary of the main recent results and achievements. The future developments of the LUNA experiment are also given. © 2013 Elsevier B.V. All rights reserved.

Published
2014
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2. Underground study of the O17(p,g)F18 reaction relevant for explosive hydrogen burning

Author

DI LEVA, ANTONINO, D. A. Scott, A. Caciolli, A. Formicola, F. Strieder, M. Aliotta, M. Anders, D. Bemmerer, C. Broggini, P. Corvisiero, Z. Elekes, Z.s. F?l?p, G. Gervino, A. Guglielmetti, C. Gustavino, G.y. Gy?rky, IMBRIANI, GIANLUCA, J. Jos?, M. Junker, M. Laubenstein, R. Menegazzo, E. Napolitani, P. Prati, V. Rigato, ROCA, VINCENZO, E. Somorjai, C. Salvo, O. Straniero, T. Sz?cs, F. Terrasi, D. Trezzi, DI LEVA, Antonino, D. A., Scott, A., Caciolli, A., Formicola, F., Strieder, M., Aliotta, M., Ander, D., Bemmerer, C., Broggini, P., Corvisiero, Z., Eleke, F?l?p, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gy?rky, G. y., Imbriani, Gianluca, J., Jos?, M., Junker, M., Laubenstein, R., Menegazzo, E., Napolitani, P., Prati, V., Rigato, Roca, Vincenzo, E., Somorjai, C., Salvo, O., Straniero, T., Sz?c, F., Terrasi, and D., Trezzi

Subjects
Nuclear Astrophysic, underground measurement, Experimental Nuclear Physics
Abstract

Background: The O17(p,γ)F18 reaction affects the production of key isotopes (e.g., F18 and O18) in the explosive hydrogen burning that powers classical novae. Under these explosive conditions, the reaction rate is dominated by contributions from a narrow resonance at Ec.m.=183keV and by the combined contributions of direct capture and low-energy tails of broad resonances. At present, the astrophysical reaction rate is not well constrained because of the lack of data in the energy region appropriate to classical novae. Purpose: This study aims at the measurement of the O17(p,γ)F18 reaction cross section in order to determine its reaction rate in the temperature region appropriate to explosive hydrogen burning in novae. Method: The O17(p,γ)F18 reaction cross section was measured using both the prompt detection of the emitted γ rays and an activation technique. Measurements were carried out at the Laboratory for Underground Nuclear Astrophysics (Gran Sasso, Italy) where the strongly reduced cosmic-ray-induced background allows for improved sensitivity compared to previous studies. Results: The O17(p,γ)F18 reaction cross section was measured in the range Ec.m.=160 to 370keV. The strength of the Ec.m.=183keV resonance, ωγ=1. 67±0.12μeV, was determined with unprecedented precision. The total S factor was obtained through a combined fit of prompt γ-ray and activation results. An overall global fit including other existing data sets was also carried out and a recommended astrophysical reaction rate is presented. Conclusions: The reaction rate uncertainty attained in this work is now below the required precision for nova models. We verified, following a full set of hydrodynamic nova models, that the abundances of oxygen and fluorine isotopes obtained with the present reaction rate are determined with 10% precision and put firmer constraints on observational signatures of novae events.

Published
2014

3. Impact of a revised $^{25}$Mg(p,$\gamma$)$^{26}$Al reaction rate on the operation of the Mg-Al cycle

Author

Daniel Bemmerer, H. P. Trautvetter, Michele Marta, Gianluca Imbriani, Carlo Broggini, A. Lemut, Luciano Piersanti, H. Costantini, Oscar Straniero, Filippo Terrasi, Vincenzo Roca, Gyuri Gyürky, Frank Strieder, Paolo Prati, C. Mazzocchi, A. Guglielmetti, B. Limata, C. Gustavino, M. Junker, A. Formicola, Roberto Menegazzo, G. Gervino, C. Rolfs, C. Rossi Alvarez, Sergio Cristallo, Antonio Caciolli, E. Somorjai, Z. Elekes, P. Corvisiero, Zsolt Fülöp, A. DiLeva, O., Straniero, Imbriani, Gianluca, F., Strieder, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, S., Cristallo, DI LEVA, Antonino, A., Formicola, Z., Eleke, Fülöp, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyürky, G. y., M., Junker, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, L., Piersanti, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, F., Terrasi, and H. P., Trautvetter

Subjects
Nuclear reaction, Proton, globular clusters: general, nuclear reactions, nucleosynthesis, abundances, stars: AGB and post-AGB, stars: WolfRayet, Astronomy and Astrophysics, Space and Planetary Science, astrofisica nucleare, Astrophysics, Evoluzione stellare, Chemical kinetics, Reaction rate, Nucleosynthesis, Nuclear astrophysics, Asymptotic giant branch, Nuclear Experiment, Physics, abundances, Presolar grains, Nuclear reactions, nucleosynthesis, abundances — Stars: AGB and post-AGB — Stars: Wolf-Rayet — globular clusters: general, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the $^{25}$Mg(p,$\gamma$)$^{26}$Al reaction affect the production of radioactive $^{26}$Al$^{gs}$ as well as the resulting Mg/Al abundance ratio. Reliable estimations of these quantities require precise measurements of the strengths of low-energy resonances. Based on a new experimental study performed at LUNA, we provide revised rates of the $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{gs}$ and the $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{m}$ reactions with corresponding uncertainties. In the temperature range 50 to 150 MK, the new recommended rate of the $^{26}$Al$^{m}$ production is up to 5 times higher than previously assumed. In addition, at T$=100$ MK, the revised total reaction rate is a factor of 2 higher. Note that this is the range of temperature at which the Mg-Al cycle operates in an H-burning zone. The effects of this revision are discussed. Due to the significantly larger $^{25}$Mg(p,$\gamma$)$^{26}$Al$^{m}$ rate, the estimated production of $^{26}$Al$^{gs}$ in H-burning regions is less efficient than previously obtained. As a result, the new rates should imply a smaller contribution from Wolf-Rayet stars to the galactic $^{26}$Al budget. Similarly, we show that the AGB extra-mixing scenario does not appear able to explain the most extreme values of $^{26}$Al/$^{27}$Al, i.e. $>10^{-2}$, found in some O-rich presolar grains. Finally, the substantial increase of the total reaction rate makes the hypothesis of a self-pollution by massive AGBs a more robust explanation for the Mg-Al anticorrelation observed in Globular-Cluster stars.

Published
2012

4. First Direct Measurement of the ^{17}O(p,\gamma)^{18}F Reaction Cross-Section at Gamow Energies for Classical Novae

Author

D. A. Scott, A. Caciolli, A. Formicola, M. Aliotta, M. Anders, D. Bemmerer, C. Broggini, M. Campeggio, P. Corvisiero, Z. Elekes, Z.s. Fulop, G. Gervino, A. Guglielmetti, C. Gustavino, G.y. Gyurky, M. Junker, M. Laubenstein, R. Menegazzo, M. Marta, E. Napolitani, P. Prati, V. Rigato, E. Somorjai, C. Salvo, O. Straniero, F. Strieder, T. Szus, F. Terrasi, D. Trezzi, DI LEVA, ANTONINO, IMBRIANI, GIANLUCA, ROCA, VINCENZO, D. A., Scott, A., Caciolli, DI LEVA, Antonino, A., Formicola, M., Aliotta, M., Ander, D., Bemmerer, C., Broggini, M., Campeggio, P., Corvisiero, Z., Eleke, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyurky, G. y., Imbriani, Gianluca, M., Junker, M., Laubenstein, R., Menegazzo, M., Marta, E., Napolitani, P., Prati, V., Rigato, Roca, Vincenzo, E., Somorjai, C., Salvo, O., Straniero, F., Strieder, T., Szu, F., Terrasi, and D., Trezzi

Subjects
Nuclear astrophysic, Proton-capture reaction, Astrophysics - Solar and Stellar Astrophysics, Reaction rate, CNO cycle, Nuclear Experiment
Abstract

Classical novae are important contributors to the abundances of key isotopes, such as the radioactive ^{18}F, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The ^{17}O(p,\gamma)^{18}F reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range Ecm = 200 - 370 keV appropriate to hydrogen burning in classical novae. In addition, the E=183 keV resonance strength, \omega \gamma=1.67\pm0.12 \mueV, has been measured with the highest precision to date. The uncertainty on the ^{17}O(p,\gamma)^{18}F reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis., Comment: accepted by Phys. Rev. Lett

Published
2012

5. The25Mg(p, γ)26Al reaction at low astrophysical energies

Author

A. Best, M. Junker, Antonio Caciolli, E. Somorjai, C. Rolfs, A. Lemut, Z. Elekes, P. Corvisiero, C. Gustavino, Oscar Straniero, Frank Strieder, Gianluca Imbriani, Michele Marta, Filippo Terrasi, A. Formicola, C. Rossi Alvarez, Daniel Bemmerer, H. P. Trautvetter, Vincenzo Roca, A. DiLeva, Paolo Prati, Zsolt Fülöp, B. Limata, Roberto Menegazzo, Gyuri Gyürky, G. Gervino, A. Guglielmetti, H. Costantini, Carlo Broggini, C. Mazzocchi, F., Strieder, Limata, BENEDICTA NORMANNA, A., Formicola, Imbriani, Gianluca, M., Junker, D., Bemmerer, Best, Andrea, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, DI LEVA, Antonino, Z., Eleke, Fülöp, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyürky, G. y., A., Lemut, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Terrasi, and H. P., Trautvetter

Subjects
Physics, Nuclear and High Energy Physics, Nuclear astrophysic, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Resolution (electron density), Resonance, Mg-Al cycle, Nuclear astrophysics, Proton-capture reaction, Reaction rate, Resonance strength, Crystal, Nuclear physics, Underground laboratory, High Energy Physics::Experiment, Atomic physics, Hpge detector, Nuclear Experiment
Abstract

In the present work we report on a new measurement of resonance strengths in the reaction 25Mg(p,gamma)26Al at E_cm= 92 and 189 keV. This study was performed at the LUNA facility in the Gran Sasso underground laboratory using a 4pi BGO summing crystal. For the first time the 92 keV resonance was directly observed and a resonance strength omega-gamma=(2.9+/-0.6)x10E-10 eV was determined. Additionally, the gamma-ray branchings and strength of the 189 keV resonance were studied with a high resolution HPGe detector yielding an omega-gamma value in agreement with the BGO measurement, but 20% larger compared to previous works.

Published
2012

6. Preparation and characterisation of isotopically enriched Ta2O5 targets for nuclear astrophysics studies

Author

Gianluca Imbriani, Tamás Szücs, H. P. Trautvetter, Oscar Straniero, Marialuisa Aliotta, Filippo Terrasi, M. Marta, G. Gervino, C. Rolfs, A. Formicola, A. Guglielmetti, Zs. Fülöp, Carlo Broggini, M. Campeggio, Gy. Gyürky, Enrico Napolitani, C. Salvo, Frank Strieder, C. Gustavino, R. Menegazzo, V. Rigato, Vincenzo Roca, Paolo Prati, Daniel Bemmerer, M. Anders, C. Rossi Alvarez, Rosanna Depalo, Antonio Caciolli, E. Somorjai, Z. Elekes, P. Corvisiero, Davide Trezzi, Douglas Scott, A. Bellini, A. Di Leva, M. Junker, A., Caciolli, D. A., Scott, A., Di Leva, A., Formicola, M., Aliotta, M., Ander, A., Bellini, D., Bemmerer, C., Broggini, M., Campeggio, P., Corvisiero, R., Depalo, Z., Eleke, Z., Fülöp, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyürky, G., Imbriani, M., Junker, M., Marta, R., Menegazzo, E., Napolitani, P., Prati, V., Rigato, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, C., Salvo, O., Straniero, F., Strieder, T., Szüc, Terrasi, Filippo, H. P., Trautvetter, D., Trezzi, DI LEVA, Antonino, Fülöp, Z. s., Gyürky, G. y., Imbriani, Gianluca, Roca, Vincenzo, and F., Terrasi

Subjects
Physics, Nuclear and High Energy Physics, stellar evolution, Proton, nuclear astrophysics, Radiochemistry, Tantalum, FOS: Physical sciences, chemistry.chemical_element, Isotopic composition, chemistry, nuclear physics, Nuclear astrophysics, Special care, Nuclear Experiment (nucl-ex), Nuclear Experiment, Stoichiometry, Beam (structure)
Abstract

The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn., accepted to EPJA

Published
2012
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7. The 25Mg(p, γ) 26Al reaction at low astrophysical energies.Physics Letters B707(2012)60

Author

F. Strieder, B. Limata, A. Formicola, G. Imbriani, M. Junker, D. Bemmerer, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, A. DiLeva, Z. Elekes, Z. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, G. Gyürky, A. Lemut, M. Marta, C. Mazzocchi, R. Menegazzo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, H. P. Trautvetter, TERRASI, Filippo, F., Strieder, B., Limata, A., Formicola, G., Imbriani, M., Junker, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, A., Dileva, Z., Eleke, Z., Fülöp, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyürky, A., Lemut, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, Terrasi, Filippo, and H. P., Trautvetter

Published
2012

8. The 14N( p,γ )15O reaction studied with a composite germanium detector

Author

M. Marta, A. Formicola, D. Bemmerer, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, Z. Elekes, Z.s. Fulop, G. Gervino, A. Guglielmetti, C. Gustavino, G.y. Gyurky, M. Junker, A. Lemut, B. Limata, C. Mazzocchi, R. Menegazzo, P. Prati, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H. P. Trautvetter, A. Vomiero, IMBRIANI, GIANLUCA, ROCA, VINCENZO, M., Marta, A., Formicola, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, Z., Eleke, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyurky, G. y., Imbriani, Gianluca, M., Junker, A., Lemut, B., Limata, C., Mazzocchi, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, and A., Vomiero

Subjects
Fisica Nucleare Sperimentale, Spettroscopia Gamma, Astrofisica Nucleare
Abstract

The rate of the carbon-nitrogen-oxygen (CNO) cycle of hydrogen burning is controlled by the 14N(p,γ )15O reaction. The reaction proceeds by capture to the ground states and several excited states in 15O. In order to obtain a reliable extrapolation of the excitation curve to astrophysical energy, fits in the R-matrix framework are needed. In an energy range that sensitively tests such fits, new cross-section data are reported here for the four major transitions in the 14N(p,γ )15O reaction. The experiment has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400-kV accelerator placed deep underground in the Gran Sasso facility in Italy. Using a composite germanium detector, summing corrections have been considerably reduced with respect to previous studies. The cross sections for capture to the ground state and to the 5181, 6172, and 6792 keV excited states in 15O have been determined at 359, 380, and 399 keV beam energy. In addition, the branching ratios for the decay of the 278-keV resonance have been remeasured.

Published
2011

9. Revision of the 15N(p, γ)16O reaction rate and oxygen abundance in H-burning zones Astronomy & Astrophysics 533(2011)

Author

A. Caciolli, C. Mazzocchi, V. Capogrosso, D. Bemmerer, C. Broggini, P. Corvisiero, H. Costantini, Z. Elekes, A. Formicola, Z.s. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, G.y. Gyürky, G. Imbriani, M. Junker, A. Lemut, M. Marta, R. Menegazzo, S. Palmerini, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, H. P. Trautvetter, A. Vomiero, TERRASI, Filippo, A., Caciolli, C., Mazzocchi, V., Capogrosso, D., Bemmerer, C., Broggini, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Fülöp, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyürky, G. y., G., Imbriani, M., Junker, A., Lemut, M., Marta, R., Menegazzo, S., Palmerini, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, and A., Vomiero

Subjects
stars: AGB and post-AGB – nuclear reactions, nucleosynthesis, abundances – novae – cataclysmic variables
Abstract

Context. The NO cycle takes place in the deepest layer of a H-burning core or shell, when the temperature exceeds T 30 × 106 K. The O depletion observed in some globular cluster giant stars, always associated with a Na enhancement, may be due to either a deep mixing during the red giant branch (RGB) phase of the star or to the pollution of the primordial gas by an early population of massive asymptotic giant branch (AGB) stars, whose chemical composition was modified by the hot bottom burning. In both cases, the NO cycle is responsible for the O depletion. Aims. The activation of this cycle depends on the rate of the 15N(p, γ)16O reaction. A precise evaluation of this reaction rate at temperatures as low as experienced in H-burning zones in stellar interiors is mandatory to understand the observed O abundances. Methods. We present a new measurement of the 15N(p, γ)16O reaction performed at LUNA covering for the first time the center of mass energy range 70−370 keV, which corresponds to stellar temperatures between 65 × 106 K and 780 × 106 K. This range includes the 15N(p, γ)16O Gamow-peak energy of explosive H-burning taking place in the external layer of a nova and the one of the hot bottom burning (HBB) nucleosynthesis occurring in massive AGB stars. Results. With the present data, we are also able to confirm the result of the previous R-matrix extrapolation. In particular, in the temperature range of astrophysical interest, the new rate is about a factor of 2 smaller than reported in the widely adopted compilation of reaction rates (NACRE or CF88) and the uncertainty is now reduced down to the 10% level.

Published
2011

10. The N14(p,γ)O15 reaction studied with a composite germanium detector Physical Review C83(2011)045804

Author

M. Marta, A. Formicola, D. Bemmerer, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, Z. Elekes, Z. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, G. Gyürky, G. Imbriani, M. Junker, A. Lemut, B. Limata, C. Mazzocchi, R. Menegazzo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, H. P. Trautvetter, A. Vomiero, TERRASI, Filippo, M., Marta, A., Formicola, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, Z., Eleke, Z., Fülöp, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyürky, G., Imbriani, M., Junker, A., Lemut, B., Limata, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, and A., Vomiero

Published
2011

11. Constraining the S factor of N15(p,γ)O16 at astrophysical energies

Author

P. J. Leblanc, G. Imbriani, J. Görres, M. Junker, R. Azuma, M. Beard, D. Bemmerer, A. Best, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, M. Couder, R. Deboer, Z. Elekes, S. Falahat, A. Formicola, Z. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, G. Gyürky, F. Käppeler, A. Kontos, R. Kuntz, H. Leiste, A. Lemut, Q. Li, B. Limata, M. Marta, C. Mazzocchi, R. Menegazzo, S. O'Brien, A. Palumbo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, E. Stech, O. Straniero, F. Strieder, W. Tan, H. P. Trautvetter, E. Uberseder, M. Wiescher, TERRASI, Filippo, P. J., Leblanc, G., Imbriani, J., Görre, M., Junker, R., Azuma, M., Beard, D., Bemmerer, A., Best, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, M., Couder, R., Deboer, Z., Eleke, S., Falahat, A., Formicola, Z., Fülöp, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyürky, F., Käppeler, A., Konto, R., Kuntz, H., Leiste, A., Lemut, Q., Li, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, S., O'Brien, A., Palumbo, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, E., Stech, O., Straniero, F., Strieder, W., Tan, Terrasi, Filippo, H. P., Trautvetter, E., Uberseder, and M., Wiescher

Published
2010

12. An actively vetoed Clover gamma-detector for nuclear astrophysics at LUNA. Eur. Phys. J. A44(2010)513-519

Author

T. SZUCS, D. BEMMERER, C. BROGGINI, A. CACIOLLI, F. CONFORTOLA, P. CORVISIERO, Z. ELEKES, A. FORMICOLA, Z.S. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G.Y. GYURKY, G. IMBRIANI, M. JUNKER, A. LEMUT, M. MARTA, C. MAZZOCCHI, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, H. P. TRAUTVETTER, TERRASI, Filippo, T., Szuc, D., Bemmerer, C., Broggini, A., Caciolli, F., Confortola, P., Corvisiero, Z., Eleke, A., Formicola, Fulop, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, Gyurky, G. Y., G., Imbriani, M., Junker, A., Lemut, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2010

13. An actively vetoed Clover γ-detector for nuclear astrophysicsat LUNA

Author

Luna, Collaboration, Szucs, T., Bemmerer, D., Broggini, C., Caciolli, A., Confortola, F., Corvisiero, P., Elekes, Z., Formicola, A., Fulop, Zs, Gervino, G., Guglielmetti, A., Gustavino, C., Gyurky, Gy, Imbriani, G., Junker, M., Lemut, A., Marta, M., Mazzocchi, C., Menegazzo, R., Prati, P., Roca, V., Rolfs, C., Rossi Alvarez, C., Somorjai, E., Oscar Straniero, Strieder, F., Terrasi, F., Trautvetter, H. P., T., Szuc, D., Bemmerer, C., Broggini, A., Caciolli, F., Confortola, P., Corvisiero, Z., Eleke, A., Formicola, F¨ul¨op, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gy¨urky, G. y., Imbriani, Gianluca, M., Junker, A., Lemut, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Subjects
Physics, Nuclear and High Energy Physics, Clover type HP Germaniun detector, Physics::Instrumentation and Detectors, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Underground Laboratories, Semiconductor detector, Nuclear physics, Nuclear astrophysics, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, Nuclear Astrophysic
Abstract

An escape-suppressed, composite high-purity germanium detector of the Clover type has been installed at the Laboratory for Underground Nuclear Astrophysics (LUNA) facility, deep underground in the Gran Sasso Laboratory, Italy. The laboratory gamma-ray background of the Clover detector has been studied underground at LUNA and, for comparison, also in an overground laboratory. Spectra have been recorded both for the single segments and for the virtual detector formed by online addition of all four segments. The effect of the escape-suppression shield has been studied as well. Despite their generally higher intrinsic background, escape-suppressed detectors are found to be well suited for underground nuclear astrophysics studies. As an example for the advantage of using a composite detector deep underground, the weak ground state branching of the Ep = 223 keV resonance in the 24Mg(p,gamma)25Al reaction is determined with improved precision., 8 pages, 6 figures, 3 tables; as accepted by Eur. Phys. J. A

Published
2010

14. New experimental study of low-energy (p,γ) resonances in magnesium isotopes. Phys. Rev. C82(2010)015801

Author

B. LIMATA, F. STRIEDER, A. FORMICOLA, G. IMBRIANI, M. JUNKER, H. W. BECKER, D. BEMMERER, A. BEST, R. BONETTI, C. BROGGINI, A. CACIOLLI, P. CORVISIERO, H. COSTANTINI, A. DILEVA, Z. ELEKES, Z.S. FÜLÖP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G.Y. GYÜRKY, A. LEMUT, M. MARTA, C. MAZZOCCHI, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, C. SALVO, E. SOMORJAI, O. STRANIERO, AND H. P. TRAUTVETTER, TERRASI, Filippo, B., Limata, F., Strieder, A., Formicola, G., Imbriani, M., Junker, H. W., Becker, D., Bemmerer, A., Best, R., Bonetti, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, A., Dileva, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, Gyürky, G. Y., A., Lemut, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, C., Salvo, E., Somorjai, O., Straniero, Terrasi, Filippo, and AND H. P., Trautvetter

Published
2010

15. Direct measurement of the 15N(p,gamma)16O total cross section at novae energies

Author

C. Rossi Alvarez, Z. Elekes, Roberto Menegazzo, Daniel Bemmerer, G. Gervino, Carlo Broggini, Vincenzo Roca, A. Formicola, Paolo Prati, P. Corvisiero, Zs. Fülöp, Antonio Caciolli, C. Gustavino, M. Junker, E. Somorjai, Oscar Straniero, R. Bonetti, H. Costantini, F. Confortola, A. Guglielmetti, C. Rolfs, Gy. Gyürky, M. Marta, B. Limata, D., Bemmerer, A., Caciolli, R., Bonetti, C., Broggini, F., Confortola, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Zs F¨, Ul¨op, G., Gervino, A., Guglielmetti, C., Gustavino, Gy, Gy¨urky, M., Junker, Limata, BENEDICTA NORMANNA, M., Marta, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, and O., Straniero

Subjects
Nuclear and High Energy Physics, CNO cycle, Hydrogen, chemistry.chemical_element, FOS: Physical sciences, Nova burning, CNO cycle, Bismuth germanate, chemistry.chemical_compound, Cross section (physics), Nuclear Experiment (nucl-ex), Nuclear Experiment, Solar and Stellar Astrophysics (astro-ph.SR), Physics, gas target, novae astrophysics, Nova (laser), Nitrogen, Isotopic composition, LUNA, Astrophysics - Solar and Stellar Astrophysics, chemistry, nuclear astrophisic, Nuclear astrophysics, BGO detector, Center of mass, Atomic physics
Abstract

The 15N(p,gamma)16O reaction controls the passage of nucleosynthetic material from the first to the second carbon-nitrogen-oxygen (CNO) cycle. A direct measurement of the total 15N(p,gamma)16O cross section at energies corresponding to hydrogen burning in novae is presented here. Data have been taken at 90-230 keV center-of-mass energy using a windowless gas target filled with nitrogen of natural isotopic composition and a bismuth germanate summing detector. The cross section is found to be a factor two lower than previously believed., Comment: LUNA collaboration; accepted by J. Phys. G

Published
2009
Full Text
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16. Ultra-sensitive in-beam gamma-ray spectroscopy for nuclear astrophysics at LUNA

Author

M. Junker, R. Bonetti, A. Lemut, A. Formicola, Matthias Laubenstein, Z. Elekes, M. Marta, C. Rolfs, C. Gustavino, Gianluca Imbriani, Vincenzo Roca, P. Corvisiero, C. Rossi Alvarez, C. Mazzocchi, Paolo Prati, H. Costantini, B. Limata, Daniel Bemmerer, Carlo Broggini, Zs. Fülöp, Gy. Gyürky, G. Gervino, Antonio Caciolli, E. Somorjai, Oscar Straniero, Frank Strieder, Filippo Terrasi, A. Guglielmetti, R. Menegazzo, L. Agostino, F. Confortola, H. P. Trautvetter, A., Caciolli, L., Agostino, D., Bemmerer, R., Bonetti, C., Broggini, F., Confortola, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Fulop, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, Gyurky, G. Y., G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, Caciolli, A., Agostino, L., Bemmerer, D., Bonetti, R., Broggini, C., Confortola, F., Corvisiero, P., Costantini, H., Elekes, Z., Formicola, A., Fulop, Z. s., Gervino, G., Guglielmetti, A., Gustavino, C., Gyurky, G. y., Imbriani, Gianluca, Junker, M., Laubenstein, M., Lemut, A., Limata, B., Marta, M., Mazzocchi, C., Menegazzo, R., Prati, P., Roca, Vincenzo, Rolfs, C., Rossi Alvarez, C., Somorjai, E., Straniero, O., Strieder, F., Terrasi, F., and Trautvetter, H. P.

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, 3H, 3He, complex mixtures, and 4He-induced reactions, Nuclear physics, Nuclear physic, Nuclear astrophysics, γ-ray spectroscopy, Physics::Accelerator Physics, Gamma spectroscopy, Nuclear Experiment (nucl-ex), Spectroscopy, Nuclear Experiment, Beam (structure), Ultra sensitive
Abstract

Ultra-sensitive in-beam gamma-ray spectroscopy studies for nuclear astrophysics are performed at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator, deep underground in Italy's Gran Sasso laboratory. By virtue of a specially constructed passive shield, the laboratory gamma-ray background for E_\gamma < 3 MeV at LUNA has been reduced to levels comparable to those experienced in dedicated offline underground gamma-counting setups. The gamma-ray background induced by an incident alpha-beam has been studied. The data are used to evaluate the feasibility of sensitive in-beam experiments at LUNA and, by extension, at similar proposed facilities., Comment: accepted, Eur. Phys. J. A

Published
2009

17. Ground state capture in 14N(p,γ)15O studied above the 259 keV resonance at LUNA

Author

A. Guglielmetti, Zs. Fülöp, Daniel Bemmerer, C. Rossi Alvarez, Carlo Broggini, Antonio Caciolli, E. Somorjai, B. Limata, C. Gustavino, A. Formicola, M. Marta, R. Menegazzo, F. Confortola, G. Gervino, H. Costantini, C. Mazzocchi, Alberto Vomiero, Gianluca Imbriani, R. Bonetti, Oscar Straniero, H. P. Trautvetter, Vincenzo Roca, Paolo Prati, Filippo Terrasi, Z. Elekes, P. Corvisiero, M. Junker, A. Lemut, C. Rolfs, Frank Strieder, Gy. Gyürky, S. Vezzu, H. P., Trautvetter, D., Bemmerer, R., Bonetti, C., Broggini, A., Caciolli, F., Confortola, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Z., Fulop, G., Gervino, A., Guglielmetti, G., Gyurky, C., Gustavino, G., Imbriani, M., Junker, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, S., Vezzu, A., Vomiero, Zs, Fäuläop, Gy, Gyäurky, Imbriani, Gianluca, Limata, BENEDICTA NORMANNA, Roca, Vincenzo, C., Rossi Alvarez, F., Terrasi, and S., Vezzù

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, Detector, Resonance, CNO cycle, Clover-type gamma detector, Ground state, underground laboratory, Nuclear Experiment, Coincidence
Abstract

We report on a new measurement of $^{14}$N(p,$\gamma$)$^{15}$O for the ground state capture transition at $E_p$ = 360, 380 and 400 keV, using the 400 kV LUNA accelerator. The true coincidence summing effect --the major source of error in the ground state capture determination-- has been significantly reduced by using a Clover--type gamma detector., Comment: 6 pages, 5 figures, Accepted for publication in Journal of Physics G

Published
2008

18. Precision study of ground state capture in the 14N(p,γ)15O reaction

Author

Marta, M., Bemmerer, D., Bonetti, R., Broggini, C., Caciolli, A., Corvisiero, P., Confortola, F., Conti, E., Costantini, H., Elekes, Z., Formicola, A., Fülöp, Z., Gervino, G., Guglielmetti, A., Gyürky, G., Gustavino, C., Imbriani, G., Junker, M., Lemut, A., Limata, B., Mazzocchi, C., Menegazzo, R., Prati, P., Roca, V., Rolfs, C., Rossi Alvarez, C., Somorjai, E., Straniero, O., Strieder, F., Terrasi, F., Trautvetter, H. P., M., Marta, A., Formicola, G., Gyurky, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, Z., Eleke, Fulop, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, R., Kunz, A., Lemut, B., Limata, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, M., Romano, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, and A., Vomiero

Subjects
Astrophysics (astro-ph), FOS: Physical sciences, radiative capture, CNO cycle, Astrophysics, Gran Sasso, LUNA, R-matrix, solar neutrinos, underground, in-beam gamma-spectrometry, Clover detector, Nuclear astrophysics, Clover segmented detector, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is controlled by the slowest process, 14N(p,gamma)15O, which proceeds by capture to the ground and several excited states in 15O. Previous extrapolations for the ground state contribution disagreed by a factor 2, corresponding to 15% uncertainty in the total astrophysical S-factor. At the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground in the Gran Sasso facility in Italy, a new experiment on ground state capture has been carried out at 317.8, 334.4, and 353.3 keV center-of-mass energy. Systematic corrections have been reduced considerably with respect to previous studies by using a Clover detector and by adopting a relative analysis. The previous discrepancy has been resolved, and ground state capture no longer dominates the uncertainty of the total S-factor., Phys. Rev. C, rapid comm., accepted

Published
2008

19. Precision study of ground state capture in the 14N(p,g)15O reaction

Author

M. Marta, A. Formicola, Gy Gyurky, D. Bemmerer, C. Broggini, A. Caciolli, P. Corvisiero, H. Costantini, Z. Elekes, Z.s. Fulop, G. Gervino, A. Guglielmetti, C. Gustavino, M. Junker, R. Kunz, A. Lemut, C. Mazzocchi, R. Menegazzo, P. Prati, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H. P. Trautvetter, IMBRIANI, GIANLUCA, LIMATA, BENEDICTA NORMANNA, ROCA, VINCENZO, ROMANO, MARIO, M., Marta, A., Formicola, Gy, Gyurky, D., Bemmerer, C., Broggini, A., Caciolli, P., Corvisiero, H., Costantini, Z., Eleke, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, M., Junker, R., Kunz, A., Lemut, Limata, BENEDICTA NORMANNA, C., Mazzocchi, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, Romano, Mario, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Abstract

The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is controlled by the slowest process, 14N(p,γ )15O, which proceeds by capture to the ground and several excited states in 15O. Previous extrapolations for the ground state contribution disagreed by a factor 2, corresponding to 15% uncertainty in the total astrophysical S factor. At the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground in the Gran Sasso facility in Italy, a new experiment on ground state capture has been carried out at 317.8, 334.4, and 353.3 keV center-of-mass energy. Systematic corrections have been reduced considerably with respect to previous studies by using a Clover detector and by adopting a relative analysis. The previous discrepancy has been resolved, and ground state capture no longer dominates the uncertainty of the total S factor.

Published
2008

20. Measurement of 25Mg(p,γ)26Al resonance strengths via gamma spectrometry

Author

Formicola, A., Best, A., Imbriani, G., Junker, M., Bemmerer, D., Bonetti, R., Broggini, C., Caciolli, A., Confortola, F., Corvisiero, P., Costantini, H., Elekes, Z., Fülöp, Z., Gervino, G., Guglielmetti, A., Gyürky, G., Gustavino, C., Lemut, A., Limata, B., Marta, M., Mazzocchi, C., Menegazzo, R., Prati, P., Roca, V., Rolfs, C., Rossi Alvarez, C., Somorjai, E., Straniero, O., Strieder, F., Terrasi, F., Trautvetter, H. P., A., Formicola, A., Best, G., Imbriani, M., Junker, D., Bemmerer, R., Bonetti, C., Broggini, A., Caciolli, F., Confortola, P., Corvisiero, H., Costantini, Z., Eleke, Fulop, Z. S., G., Gervino, A., Guglielmetti, G., Gyurky, C., Gustavino, A., Lemut, B., Limata, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Subjects
LUNA, Experiment, Nuclear Astrophysics, Resonance strengths
Abstract

The COMPTEL instrument performed the first mapping of the 1.809 MeV photons in the Galaxy, triggering considerable interest in determing the sources of interstellar 26Al. The predicted 26Al is too low compared to the observation, for a better understanding more accurate rates for the 25Mg(p,gamma)26Al reaction are required. The 25Mg(p,gamma)26Al reaction has been investigated at the resonances at Er= 745; 418; 374; 304 keV at Ruhr-Universität Bochum using a Tandem accelerator and a 4pi NaI detector. In addition the resonance at Er = 189 keV has been measured deep underground laboratory at Laboratori Nazionali del Gran Sasso, exploiting the strong suppression of cosmic background. This low resonance has been studied with the 400 kV LUNA accelerator and a HPGe detector. The preliminary results of the resonance strengths will be reported.

Published
2008

21. The 3He(α,γ)7Be S-factor at solar energies: the prompt &gamma experiment at LUNA

Author

H. COSTANTINI, D. BEMMERER, F. CONFORTOLA, A. FORMICOLA, G.Y. GYURKY, P. BEZZON, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z.S. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, H. P. TRAUTVETTER, TERRASI, Filippo, H., Costantini, D., Bemmerer, F., Confortola, A., Formicola, Gyurky, G. Y., P., Bezzon, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fulop, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2008

22. Comparison of the LUNA 3He(α,γ)7Be activation results with earlier measurements and model calculations

Author

H. Costantini, F. Confortola, Daniel Bemmerer, A. Formicola, R. Bonetti, Z. Elekes, A. Guglielmetti, M. Laubenstein, Carlo Broggini, Oscar Straniero, Gianluca Imbriani, Filippo Terrasi, M. Junker, A. Lemut, V. Lozza, P. Corvisiero, R. Menegazzo, Frank Strieder, C. Rolfs, E. Somorjai, Gy. Gyürky, B. Limata, C. Rossi Alvarez, G. Gervino, Zs. Fülöp, C. Gustavino, M. Marta, H. P. Trautvetter, Vincenzo Roca, Paolo Prati, G., Gyurky, D., Bemmerer, F., Confortola, H., Costantini, A., Formicola, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Z., Fulop, G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, G., Gyürky, Z., Fülöp, Imbriani, Gianluca, Limata, BENEDICTA NORMANNA, Roca, Vincenzo, C., Rossi Alvarez, and F., Terrasi

Subjects
Physics, Nuclear and High Energy Physics, comparison with other data, S-factor, Theoretical models, Zero-point energy, Alpha (ethology), FOS: Physical sciences, activation measurement, nuclear reaction, Nuclear physics, Cross section (physics), Activation method, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Recently, the LUNA collaboration has carried out a high precision measurement on the 3He(alpha,gamma)7Be reaction cross section with both activation and on-line gamma-detection methods at unprecedented low energies. In this paper the results obtained with the activation method are summarized. The results are compared with previous activation experiments and the zero energy extrapolated astrophysical S factor is determined using different theoretical models., Comment: Accepted for publication in Journal of Physics G

Published
2008

23. 3He(alpha,gamma)7Be cross section at low energies

Author

G.Y. GYÜRKY, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, D. BEMMERER, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z.S. FÜLÖP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, LOZZA, VALENTINA, Gyürky, G. Y., F., Confortola, H., Costantini, A., Formicola, D., Bemmerer, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Subjects
Astrophysics (astro-ph), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Astrophysics, Nuclear Experiment
Abstract

The flux of 7Be and 8B neutrinos from the Sun and the production of 7Li via primordial nucleosynthesis depend on the rate of the 3He(alpha,gamma)7Be reaction. In extension of a previous study showing cross section data at 127 - 167 keV center of mass energy, the present work reports on a measurement of the 3He(alpha,gamma)7Be cross section at 106 keV performed at Italy's Gran Sasso underground laboratory by the activation method. This energy is closer to the solar Gamow energy than ever reached before. The result is sigma = 0.567 +- 0.029(stat) +- 0.016(syst) nbarn. The data are compared with previous activation studies at high energy, and a recommended S(0) value for all 3He(alpha,gamma)7Be activation studies, including the present work, is given., Accepted for publication in PRC

Published
2007

24. Astrophysical S factor of the 3He(alpha,gamma)7Be reaction measured at low energy via detection of prompt and delayed gamma rays

Author

F. CONFORTOLA, D. BEMMERER, H. COSTANTINI, A. FORMICOLA, G.Y. GYÜRKY, P. BEZZON, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z.S. FÜLÖP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, LOZZA, VALENTINA, F., Confortola, D., Bemmerer, H., Costantini, A., Formicola, Gyürky, G. Y., P., Bezzon, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Published
2007

25. 3He(α,γ)7Be cross section at low energies

Author

G. GYURKY, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, D. BEMMERER, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. PRATI, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, IMBRIANI, GIANLUCA, ROCA, VINCENZO, G., Gyurky, F., Confortola, H., Costantini, A., Formicola, D., Bemmerer, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Z., Fulop, G., Gervino, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter

Abstract

The flux of Be-7 and B-8 neutrinos from the Sun and the production of Li-7 via primordial nucleosynthesis depend on the rate of the He-3(alpha,gamma)Be-7 reaction. In an extension of a previous study showing cross section data at 127-167 keV center-of-mass energy, the present work reports on a measurement of the He-3(alpha,gamma)Be-7 cross section at 106 keV performed at Italy's Gran Sasso underground laboratory by the activation method. This energy is closer to the solar Gamow energy than ever reached before. The result is sigma=0.567 +/- 0.029(stat)+/- 0.016(syst) nb. The data are compared with previous activation studies at high energy, and a recommended S(0) value for all He-3(alpha,gamma)Be-7 activation studies, including the present work, is given.

Published
2007

26. Astrophysical S factor of the 3He7Be reaction measured at low energy via detection of prompt and delayed gamma rays

Author

F. Confortola, D. Bemmerer, H. Costantini, A. Formicola, G.y. Gyurky, P. Bezzon, R. Bonetti, C. Broggini, P. Corvisiero, Z. Elekes, Z.s. Fulop, G. Gervino, A. Guglielmetti, C. Gustavino, G. Imbriani, M. Junker, M. Laubenstein, A. Lemut, B. Limata, V. Lozza, M. Marta, R. Menegazzo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, H. P. Trautvetter, TERRASI, Filippo, F., Confortola, D., Bemmerer, H., Costantini, A., Formicola, Gyurky, G. y., P., Bezzon, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2007

27. Astrophysical S factor of the He3(α,γ)Be7 reaction measured at low energy via detection of prompt and delayed γ rays

Author

F. Confortola, D. Bemmerer, H. Costantini, A. Formicola, G.y. Gyürky, P. Bezzon, R. Bonetti, C. Broggini, P. Corvisiero, Z. Elekes, Z.s. Fülöp, G. Gervino, A. Guglielmetti, C. Gustavino, M. Junker, M. Laubenstein, A. Lemut, B. Limata, V. Lozza, M. Marta, R. Menegazzo, P. Prati, C. Rolfs, C. Alvarez, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H. Trautvetter, IMBRIANI, GIANLUCA, ROCA, VINCENZO, F., Confortola, D., Bemmerer, H., Costantini, A., Formicola, Gyürky, G. y., P., Bezzon, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Alvarez, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H., Trautvetter

Subjects
solar neutrino, Experimental nuclear physic, nuclear astrophysic
Abstract

Solar neutrino fluxes depend both on astrophysical and on nuclear physics inputs, namely on the cross sections of the reactions responsible for neutrino production inside the Solar core. While the flux of solar 8B neutrinos has been recently measured at Superkamiokande with a 3.5% uncertainty and a precise measurement of 7Be neutrino flux is foreseen in the next future, the predicted fluxes are still affected by larger errors. The largest nuclear physics uncertainty to determine the fluxes of 8B and 7Be neutrinos comes from the 3He(alpha,gamma )7Be reaction. The uncertainty on its S-factor is due to an average discrepancy in results obtained using two different experimental approaches: the detection of the delayed γ rays from 7Be decay and the measurement of the prompt-gamma emission. Here we report on a new high precision experiment performed with both techniques at the same time. Thanks to the low background conditions of the Gran Sasso LUNA accelerator facility, the cross section has been measured at Ec.m. = 170, 106, and 93 keV, the latter being the lowest interaction energy ever reached. The S-factors from the two methods do not show any discrepancy within the experimental errors. An extrapolated S(0) = 0.560 +/- 0.017 keVbarn is obtained. Moreover, branching ratios between the two prompt-gamma transitions have been measure with 5–8% accuracy.

Published
2007

28. Measurement of 25Mg(p; gamma)26Al resonance strengths via gamma spectrometry

Author

A. Formicola, BEST, ANDREAS, M. Junker, D. Bemmerer, R. Bonetti, C. Broggini, A. Caciolli, F. Confortola, P. Corvisiero, H. Costantini, Z. Elekes, Z. Fulop, G. Gervino, A. Guglielmetti, G. Gyürky, C. Gustavino, A. Lemut, M. Marta, C. Mazzocchi, R. Menegazzo, P. Prati, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, F. Terrasi, H. P. T.r.a.u.t.v.e.t.t.e.r. In: Journal of physics G. : nuclear, particle p.h.y.s.i.c.s. ISSN 0954 3.8.9.9. 3.5.:.1. p. 014013 0.1.4.0.1.3., IMBRIANI, GIANLUCA, LIMATA, BENEDICTA NORMANNA, ROCA, VINCENZO, A., Formicola, Best, Andrea, Imbriani, Gianluca, M., Junker, D., Bemmerer, R., Bonetti, C., Broggini, A., Caciolli, F., Confortola, P., Corvisiero, H., Costantini, Z., Eleke, Z., Fulop, G., Gervino, A., Guglielmetti, G., Gyürky, C., Gustavino, A., Lemut, Limata, BENEDICTA NORMANNA, M., Marta, C., Mazzocchi, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, nuclear, H. P. T. r. a. u. t. v. e. t. t. e. r. In: Journal of physics G., and Particle, p. h. y. s. i. c. s. ISSN 0954 3. 8. 9. 9. 3. 5. :. 1. p. 014013 0. 1. 4. 0. 1. 3.

Subjects
Physics, Nuclear and High Energy Physics, COSMIC cancer database, Photon, Detector, Resonance, FOS: Physical sciences, Mass spectrometry, Galaxy, Nuclear physics, Underground laboratory, Mg abbundance, Nuclear Experiment (nucl-ex), Hpge detector, Nuclear Experiment, nuclear astrophysic
Abstract

The COMPTEL instrument performed the first mapping of the 1.809 MeV photons in the Galaxy, triggering considerable interest in determing the sources of interstellar 26Al. The predicted 26Al is too low compared to the observation, for a better understanding more accurate rates for the 25Mg(p; gamma)26Al reaction are required. The 25Mg(p;gamma)26Al reaction has been investigated at the resonances at Er= 745; 418; 374; 304 keV at Ruhr-Universitat-Bochum using a Tandem accelerator and a 4piNaI detector. In addition the resonance at Er = 189 keV has been measured deep underground laboratory at Laboratori Nazionali del Gran Sasso, exploiting the strong suppression of cosmic background. This low resonance has been studied with the 400 kV LUNA accelerator and a HPGe detector. The preliminary results of the resonance strengths will be reported., Comment: Accepted for publication in Journal of Physics G

Published
2007
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29. 3He)7Be cross section at low energies

Author

G.y. Gyurky, F. Confortola, H. Costantini, A. Formicola, D. Bemmerer, R. Bonetti, C. Broggini, P. Corvisiero, Z. Elekes, Z.s. Fulop, G. Gervino, A. Guglielmetti, C. Gustavino, G. Imbriani, M. Junker, M. Laubenstein, A. Lemut, B. Limata, V. Lozza, M. Marta, R. Menegazzo, P. Prati, V. Roca, C. Rolfs, C. Rossi Alvarez, E. Somorjai, O. Straniero, F. Strieder, H. P. Trautvetter, TERRASI, Filippo, Gyurky, G. y., F., Confortola, H., Costantini, A., Formicola, D., Bemmerer, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., Rossi Alvarez, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2007

30. Activation Measurement of the 3He(alpha,gamma)7Be Cross Section at Low Energy

Author

D. BEMMERER, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, G. GYURKY, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. . PRATI, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, F. TERRASI, H. P. TRAUTVETTER, IMBRIANI, GIANLUCA, ROCA, VINCENZO, D., Bemmerer, F., Confortola, H., Costantini, A., Formicola, Gyürky, G. Y., R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Fülöp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, Lozza, Valentina, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, G., Gyurky, Z., Fulop, Imbriani, Gianluca, V., Lozza, Prati, P., and Roca, Vincenzo

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Nuclear Experiment (nucl-ex), Astrophysics, Nuclear Experiment
Abstract

The nuclear physics input from the 3He(alpha,gamma)7Be cross section is a major uncertainty in the fluxes of 7Be and 8B neutrinos from the Sun predicted by solar models and in the 7Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-gamma technique and with inferior precision. Using a windowless gas target, high beam intensity, and low background gamma-counting facilities, the 3He(alpha,gamma)7Be cross section has been determined at 127, 148, and 169 keV center-of-mass energy with a total uncertainty of 4%. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3He(alpha,gamma)7Be astrophysical S factor to solar energies.

Published
2006

31. Activation measurement of the 3He(a,g)7Be cross section at low energy

Author

D. BEMMERER, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, G. GYU, RKY, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z. FU, LOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, H. P. TRAUTVETTER, TERRASI, Filippo, D., Bemmerer, F., Confortola, H., Costantini, A., Formicola, G., Gyu, Rky, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Z., Fu, Lop, G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2006

32. Study of beam heating effect in a gas target through Rutherford scattering

Author

Z. Elekes, P. Corvisiero, E. Somorjai, R. Menegazzo, Filippo Terrasi, Gyuri Gyürky, M. Marta, Gianluca Imbriani, C. Gustavino, B. Limata, A. Guglielmetti, M. Junker, Frank Strieder, Mario R. Romano, A. Lemut, H. P. Trautvetter, C. Rolfs, Daniel Bemmerer, Vincenzo Roca, Paolo Prati, Carlo Broggini, C. Boiano, M. L. Casanova, C. Rossi Alvarez, A. Formicola, F. Confortola, G. Gervino, Zsolt Fülöp, R. Bonetti, H. Costantini, M., Marta, F., Confortola, D., Bemmerer, C., Boiano, R., Bonetti, C., Broggini, M., Casanova, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Z., Fulop, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyurky, Imbriani, Gianluca, M., Junker, A., Lemut, Limata, BENEDICTA NORMANNA, R., Menegazzo, P., Prati, Roca, Vincenzo, C., Rolf, Romano, Mario, C., Rossi Alvarez, E., Somorjai, F., Strieder, F., Terrasi, and H. P., Trautvetter

Subjects
Physics, Experimental Nuclear Physic, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Preamplifier, Density reduction, underground laboratory, Ion, Nuclear physics, symbols.namesake, Cross section (physics), symbols, Silicon detector, Rutherford scattering, Instrumentation, Beam (structure), Heating effect, beam eathing gas target
Abstract

A systematic study of α -beam heating effect on a windowless gas target through Rutherford scattering is described. For such measurements, an ion implanted commercial silicon detector to reveal 100–250 keV alphas is used coupled with a low-noise home-made preamplifier. The results on density reduction of the gas in the target due to beam heating are discussed and their importance for high precision cross section measurements at very low energies are underlined.

Published
2006

33. Low energy measurement of the 14N(p,γ)15O total cross section at the LUNA underground facility

Author

D. BEMMERER, F. CONFORTOLA, H. COSTANTINI, A. FORMICOLA, G. GYU, RKY, R. BONETTI, C. BROGGINI, P. CORVISIERO, Z. ELEKES, Z. FU, LOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. IMBRIANI, M. JUNKER, M. LAUBENSTEIN, A. LEMUT, B. LIMATA, V. LOZZA, M. MARTA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, C. ROSSI ALVAREZ, E. SOMORJAI, O. STRANIERO, F. STRIEDER, H. P. TRAUTVETTER, TERRASI, Filippo, D., Bemmerer, F., Confortola, H., Costantini, A., Formicola, G., Gyu, Rky, R., Bonetti, C., Broggini, P., Corvisiero, Z., Eleke, Z., Fu, Lop, G., Gervino, A., Guglielmetti, C., Gustavino, G., Imbriani, M., Junker, M., Laubenstein, A., Lemut, B., Limata, V., Lozza, M., Marta, R., Menegazzo, P., Prati, V., Roca, C., Rolf, C., ROSSI ALVAREZ, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2006

34. Study of beam heating effects in a gas target through Rutherford scattering

Author

M. MARTA, F. CONFORTOLA, D. BEMMERER, C. BOIANO, R. BONETTI, C. BROGGINI, M. CASANOVA, P. CORVISIERO, H. COSTANTINI, Z. ELEKES, A. FORMICOLA, Z. FULOP, G. GERVINO, A. GUGLIELMETTI, C. GUSTAVINO, G. GYURKY, G. IMBRIANI, M. JUNKER, A. LEMUT, B. LIMATA, R. MENEGAZZO, P. PRATI, V. ROCA, C. ROLFS, M. ROMANO, C. ROSSI ALVAREZ, E. SOMORJAI, F. STRIEDER, H. P. TRAUTVETTER, TERRASI, Filippo, M., Marta, F., Confortola, D., Bemmerer, C., Boiano, R., Bonetti, C., Broggini, M., Casanova, P., Corvisiero, H., Costantini, Z., Eleke, A., Formicola, Z., Fulop, G., Gervino, A., Guglielmetti, C., Gustavino, G., Gyurky, G., Imbriani, M., Junker, A., Lemut, B., Limata, R., Menegazzo, P., Prati, V., Roca, C., Rolf, M., Romano, C., ROSSI ALVAREZ, E., Somorjai, F., Strieder, Terrasi, Filippo, and H. P., Trautvetter

Published
2006

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