277 results on '"IMBRIANI, GIANLUCA"'
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252. First measurement of the 14N(p,gamma)15O cross section down to 70 keV
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Carlo Broggini, Gianluca Imbriani, R. Bonetti, C. Rossi Alvarez, F. Confortola, Oscar Straniero, A. Guglielmetti, Filippo Terrasi, Daniel Bemmerer, Vincenzo Roca, João Cruz, B. Limata, Frank Strieder, Paolo Prati, G. Gervino, H. Costantini, P. Corvisiero, A. Formicola, A. P. Jesus, Zs. Fülöp, E. Somorjai, Gy. Gyürky, C. Rolfs, Detlef Rogalla, F. Schümann, C. Gustavino, Roberto Menegazzo, H. P. Trautvetter, M. Junker, Mario R. Romano, A. Lemut, A., Lemut, D., Bemmerer, F., Confortola, R., Bonetti, C., Broggini, Corvisiero, _. P., H., Costantini, J., Cruz, A., Formicola, Fulop, Z. s., G., Gervino, A., Guglielmetti, C., Gustavino, Gyurky, G. y., Imbriani, Gianluca, A. P., Jesu, M., Junker, B., Limata, R., Menegazzo, P., Prati, Roca, Vincenzo, D., Rogalla, C., Rolf, Romano, Mario, C., Rossi Alvarez, F., Shumann, E., Somorjai, O., Straniero, F., Strieder, and F., Terrasi
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Nuclear and High Energy Physics ,CNO cycle ,Explosive material ,Hydrogen ,Cross section measurement ,14N(p, γ)15O ,AGB stars ,Hydrogen shell burning ,Radiative capture ,Underground nuclear astrophysics ,Thermonuclear reaction ,chemistry.chemical_element ,FOS: Physical sciences ,Astrophysics ,Resonance (particle physics) ,γ)15O ,Nuclear physics ,Cross section (physics) ,14N(p ,Nuclear Experiment (nucl-ex) ,Nuclear Experiment ,Physics ,Detector ,Astrophysics (astro-ph) ,Stars ,chemistry ,Atomic physics - Abstract
In stars with temperatures above 20 × 10 6 K , hydrogen burning is dominated by the CNO cycle. Its rate is determined by the slowest process, the 14N(p, γ)15O reaction. Deep underground in Italy's Gran Sasso laboratory, at the LUNA 400 kV accelerator, the cross section of this reaction has been measured at energies much lower than ever achieved before. Using a windowless gas target and a 4π BGO summing detector, direct cross section data has been obtained down to 70 keV, reaching a value of 0.24 picobarn. The Gamow peak has been covered by experimental data for several scenarios of stable and explosive hydrogen burning. In addition, the strength of the 259 keV resonance has been remeasured. The thermonuclear reaction rate has been calculated for temperatures 90 – 300 × 10 6 K , for the first time with negligible impact from extrapolations.
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- 2006
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253. Study of beam heating effect in a gas target through Rutherford scattering
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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
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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.
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- 2006
254. Measurement of 3He(α, γ)7Be with ERNA Recoil Separator
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A. Ordine, Gianluca Imbriani, Mario R. Romano, L. Gialanella, Antonio D'Onofrio, Frank Strieder, Vincenzo Roca, M. De Cesare, Zsolt Fülöp, N. De Cesare, F. Schümann, C. Rolfs, A. Di Leva, Filippo Terrasi, Carmine Lubritto, D. Rogalla, R. Kunz, H.‐P. Trauttvetter, E. Somorjai, Gyuri Gyürky, D. Schürmann, DI LEVA, Antonino, L., Gialanella, D., Schürmann, F., Strieder, D., Rogalla, M., de Cesare, N., De Cesare, A., D'Onofrio, Z., Fülöp, G., Gyürky, Imbriani, Gianluca, R., Kunz, C., Lubritto, A., Ordine, Roca, Vincenzo, C., Rolf, Romano, Mario, F., Schümann, E., Somorjai, F., Terrasi, H. P., Trauttvetter, DI LEVA, A, Gialanella, L, Schrmann, D, Strieder, F, Rogalla, D, DE CESARE, M, DE CESARE, N, D'Onofrio, Antonio, Flp, Z, Gyrky, G, Imbriani, G, Kunz, R, Lubritto, Carmine, Ordine, A, Roca, V, Rolfs, C, Romano, M, Schmann, F, Somorjai, E, Terrasi, Filippo, and Trauttvetter, H. P.
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Physics ,solar neutrino ,S-factor ,Solar neutrino ,windowless gas target ,Abundance of the chemical elements ,Nuclear physics ,Big Bang nucleosynthesis ,Recoil separator ,Nucleosynthesis ,Helium-3 ,Nuclear astrophysics ,gamma-ray detection ,Radioactive decay ,big bang nucleosyntesi - Abstract
The 3He(α, γ)7Be reaction plays an important role in the interpretation of the results of the solar neutrino experiments, since the estimate of the oscillation parameters relies on the solar neutrino spectrum, calculated by solar models. The high energy component in this spectrum is mainly produced by the decay of 7Be and 8B. The uncertainty in the 3He(α, γ) 7Be cross section is also one of the largest contributions to the uncertainty on the predicted primordial 7Li abundance in Big Bang Nucleosynthesis calculations. Previous measurements of the 3He(α, γ)7Be cross section have been performed detecting the capture γ-rays or, alternatively, measuring the activity of the synthesized 7Be. While the results of the two different approaches agree on the energy dependence of the astrophysical S factor, they disagree in the extrapolated S34(0) value at a 3σ level. A novel approach uses the European Recoil separator for Nuclear Astrophysics (ERNA) to detect directly the 7Be ions produced in the reaction and, additionally, the coincident detection of the capture γ-rays. © 2006 American Institute of Physics.
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- 2006
255. Decay of 7Be in metallic environment
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Lucio Gialanella, Gianluca Imbriani, Frank Strieder, Zs. Fülöp, Mario R. Romano, C. Rolfs, D. Schürmann, Gy. Gyürky, Filippo Terrasi, B. Limata, Antonio D'Onofrio, F. Raiola, E. Somorjai, Detlef Rogalla, N. De Cesare, Vincenzo Roca, Fülöp, Z. s., Gyürky, G. y., E., Somorjai, D., Schürmann, F., Raiola, F., Strieder, C., Rolf, B. N., Limata, L., Gialanella, Imbriani, Gianluca, Roca, Vincenzo, Romano, Mario, N., De Cesare, A., D'Onofrio, D., Rogalla, and F., Terrasi
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Systematic error ,Metal ,Physics ,Nuclear and High Energy Physics ,Electron capture ,visual_art ,visual_art.visual_art_medium ,Half-life ,Electron configuration ,Atomic physics ,Experimental Nuclear Physics - Abstract
The electron capture half life of 7 Be implanted into different metals has been measured with high precision in order to search for a possible dependence of the decay rate on the electron configuration around the 7 Be atoms. In order to reduce systematic errors, the half life in different metals is measured by three laboratories simultaneously using different experimental setups. The measurements and data analysis are in progress, preliminary results are presented.
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- 2005
256. Recent results from the LUNA facility at Gran Sasso
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R. Menegazzo, Carlo Broggini, Gyuri Gyürky, C. Rolfs, G. Gervino, Daniel Bemmerer, Frank Strieder, Gianluca Imbriani, Zsolt Fülöp, A. Guglielmetti, R. Bonetti, C. Rossi Alvarez, A. P. Jesus, F. Confortola, M. Junker, Mario R. Romano, A. Lemut, F. Schümann, H. P. Trautvetter, E. Somorjai, H. Costantini, A. Formicola, Vincenzo Roca, P. Corvisiero, Paolo Prati, Oscar Straniero, Filippo Terrasi, João Cruz, C. Gustavino, P., Prati, D., Bemmerer, R., Bonetti, G., Broggini, F., Confortola, P., Corvisiero, H., Costantini, J., Cruz, A., Formicola, Z., Fulop, G., Gervino, A., Guglielmetti, C., Gustavino, C., Gyurky, Imbriani, Gianluca, A. P., Jesu, M., Junker, A., Lemut, R., Menegazzo, Roca, Vincenzo, C., Rolf, M., Romano, C., ROSSI ALVAREZ, F., Shumann, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, and H. P., Trautvetter
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Nuclear physics ,Crystal ,Physics ,Nuclear and High Energy Physics ,Detector ,Phase (waves) ,Measure (physics) ,Hpge detector ,National laboratory - Abstract
The 14N(p,γ)15O reaction has been investigated by the LUNA experiment at the National Laboratory of Gran Sasso (LNGS). This study has been performed with two different setups. The first one, suitable for the detection of γ-rays produced by single transitions, has been based on an HPGe detector and a solid target. In a second phase, we used a BGO summing crystal as a detector and a windowless gas target. The BGO high detection efficiency and the target purity allowed us to measure the total S factor down to Ecm = 70 keV.
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- 2005
257. First direct measurement of the total cross-section of 12C(α,γ)16O
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D. Schürmann, A. Di Leva, L. Gialanella, D. Rogalla, F. Strieder, N. De Cesare, A. D'Onofrio, G. Imbriani, R. Kunz, C. Lubritto, A. Ordine, V. Roca, C. Rolfs, M. Romano, F. Schümann, F. Terrasi, H. -P. Trautvetter, D., Schürmann, DI LEVA, Antonino, L., Gialanella, D., Rogalla, F., Strieder, N., De Cesare, A., D'Onofrio, Imbriani, Gianluca, R., Kunz, C., Lubritto, A., Ordine, Roca, Vincenzo, C., Rolf, Romano, Mario, F., Schümann, F., Terrasi, and H. P., Trautvetter
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Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Inverse kinematics ,Separator (oil production) ,Alpha (navigation) ,Stellar helium burnung ,Nuclear physics ,Cross section (physics) ,Recoil ,Nuclear Experiment ,Experimental nuclear physic ,Experimental Nuclear Astrophysic ,Energy (signal processing) - Abstract
The total cross section of 12C(alpha,gamma)16O was measured for the first time by a direct and ungated detection of the 16O recoils. This measurement in inverse kinematics using the recoil mass separator ERNA in combination with a windowless He gas target allowed to collect data with high precision in the energy range E=1.9 to 4.9 MeV. The data represent new information for the determination of the astrophysical S(E) factor.
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- 2005
258. Feasibility of low energy radiative capture experiments at the LUNA underground accelerator facility
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Gianluca Imbriani, Mario R. Romano, Daniel Bemmerer, Matthias Junker, Gy. Gyürky, Roberto Menegazzo, F. Confortola, A. P. Jesus, C. Rossi Alvarez, E. Somorjai, Oscar Straniero, C. Gustavino, C. Rolfs, H. P. Trautvetter, Filippo Terrasi, P. Corvisiero, João Cruz, F. Schümann, A. Guglielmetti, Paolo Prati, A. Lemut, G. Gervino, Detlef Rogalla, A. Formicola, B. Limata, Zs. Fülöp, R. Bonetti, Alberto Vomiero, H. Costantini, C. Broggini, Vincenzo Roca, F. Strieder, D., Bemmerer, F., Confortola, A., Lemut, R., Bonetti, C., Broggini, P., Corvisiero, H., Costantini, J., Cruz, A., Formicola, Flp, Z. S., G., Gervino, A., Guglielmetti, C., Gustavino, Gyrky, G. Y., G., Imbriani, A. P., Jesu, M., Junker, B., Limata, R., Menegazzo, P., Prati, V., Roca, D., Rogalla, C., Rolf, M., Romano, C., ROSSI ALVAREZ, F., Schmann, E., Somorjai, O., Straniero, F., Strieder, Terrasi, Filippo, H. P., Trautvetter, A., Vomiero, Fülöp, Z. s., Gyürky, G. y., Imbriani, Gianluca, Roca, Vincenzo, Romano, Mario, C., Rossi Alvarez, F., Schümann, F., Terrasi, Fulop, Z. S., Gyurky, G. Y., F., Schumann, and AND A., Vomiero
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Nuclear reaction ,Physics ,Experimental Nuclear Physic ,Nuclear and High Energy Physics ,Proton ,Gamma ray ,chemistry.chemical_element ,FOS: Physical sciences ,Germanium ,Bismuth germanate ,underground laboratory ,Nuclear physics ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,symbols ,Nuclear astrophysics ,Nuclear Experiment (nucl-ex) ,Nuclear Astrophysic ,Doppler effect ,Nuclear Experiment ,Beam (structure) - Abstract
The LUNA (Laboratory Underground for Nuclear Astrophysics) facility has been designed to study nuclear reactions of astrophysical interest. It is located deep underground in the Gran Sasso National Laboratory, Italy. Two electrostatic accelerators, with 50 and 400 kV maximum voltage, in combination with solid and gas target setups allowed to measure the total cross sections of the radiative capture reactions $^2$H(p,$\gamma$)3He and $^{14}$N(p,$\gamma$)$^{15}$O within their relevant Gamow peaks. We report on the gamma background in the Gran Sasso laboratory measured by germanium and bismuth germanate detectors, with and without an incident proton beam. A method to localize the sources of beam induced background using the Doppler shift of emitted gamma rays is presented. The feasibility of radiative capture studies at energies of astrophysical interest is discussed for several experimental scenarios., Comment: Submitted to Eur. Phys. J. A
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- 2005
259. Recoil separator ERNA: charge state distribution, target density, beam heating, and longitudinal acceptance
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Vincenzo Roca, Lucio Gialanella, Gianluca Imbriani, D. Schürmann, Antonio D'Onofrio, Carmine Lubritto, J. N. Klug, A. Di Leva, H. Röcken, N. De Cesare, A. Ordine, Filippo Terrasi, H. P. Trautvetter, C. Rolfs, F. Schümann, Detlef Rogalla, Frank Strieder, Mario R. Romano, Schürmann, D., Strieder, F., DI LEVA, A., Gialanella, L., DE CESARE, N., D'Onofrio, Antonio, Imbriani, G., Klug, J., Lubritto, Carmine, Ordine, A., Roca, V., Röcken, H., Rolfs, C., Rogalla, D., Romano, M., Schümann, F., Terrasi, Filippo, Trautvetter, H. P., Schuermann, D., DI LEVA, Antonino, De Cesare, N., D'Onofrio, A., Imbriani, Gianluca, Lubritto, C., Roca, Vincenzo, Rocken, H., Romano, Mario, Schuemann, F., and Terrasi, F.
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Physics ,Nuclear and High Energy Physics ,Physics::Instrumentation and Detectors ,Projectile ,Separator (oil production) ,Charge (physics) ,Recoil separator ,Nuclear physics ,Cross section (physics) ,Nuclear Astrophysics ,Nuclear Experiment ,State distribution ,Dynamitron ,Experimental nuclear physic ,Instrumentation ,Beam (structure) - Abstract
For improved cross section measurements of the reaction 12 C ( α , γ ) 16 O in inverted kinematics, a recoil separator ERNA is developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with high efficiency. The 16O recoils are produced by the 12C projectiles in a windowless 4He gas target. We report on the charge state distribution of the 16O recoils, the gas target density, the beam heating of the gas target, and the acceptance of the separator along the extended gas target.
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- 2004
260. Evolution and nucleosynthesis of primordial low-mass stars
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Gianluca Imbriani, Gianpiero Mangano, Ofelia Pisanti, Ilenia Picardi, Marco Limongi, Gennaro Miele, Alessandro Chieffi, Oscar Straniero, Picardi, I., Chieffi, A., Limongi, M., Pisanti, Ofelia, Miele, Gennaro, Mangano, G., Straniero, O., and Imbriani, Gianluca
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Physics ,Convection ,Metallicity ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Mantle (geology) ,Stars: interior ,Stars ,Stars: evolution ,Stars: low ,Space and Planetary Science ,Nucleosynthesis ,Mass, brown dwarf ,Asymptotic giant branch ,Nuclear reactions, nucleosynthesis, abundance ,Low Mass ,Chemical composition - Abstract
We discuss in detail the evolutionary properties of low-mass stars (M ≤ 1 M⊙) having metallicity lower than Z = 10-6 from the pre-main sequence up to (almost) the end of the early asymptotic giant branch phase. We also discuss the possibility that the large [C/Fe], [N/Fe] observed on the surface of the most iron-poor star currently known, HE 0107-5240, could be attributed to the autopollution induced by the penetration of the He convective shell into the H-rich mantle during the He core flash of a low-mass, very low metallicity star. On the basis of a quite detailed analysis, we conclude that the autopollution scenario cannot be responsible for the observed chemical composition of HE 0107-5240.
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- 2004
261. Recoil separator ERNA: Gas target and beam suppression
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Lucio Gialanella, Gianluca Imbriani, N. De Cesare, Carmine Lubritto, D. Schürmann, Filippo Terrasi, Vincenzo Roca, A. Ordine, Mario R. Romano, F. Schümann, Frank Strieder, A. Di Leva, H. P. Trautvetter, Detlef Rogalla, C. Rolfs, H. Röcken, Antonio D'Onofrio, J. N. Klug, Gialanella, Lucio, Schurmann, D, Strieder, F, Di Leva, A, De Cesare, N, D'Onofrio, Antonio, Imbriani, G, Klug, J, Lubritto, Carmine, Ordine, A, Roca, V, Rocken, H, Rolfs, C, Rogalla, D, Romano, M, Schumann, F, Terrasi, Filippo, Trauttvetter, H. P., L., Gialanella, D., Schürmann, F., Strieder, DI LEVA, Antonino, N., De Cesare, A., D’Onofrio, Imbriani, Gianluca, J., Klug, C., Lubritto, A., Ordine, Roca, Vincenzo, H., Röcken, C., Rolf, D., Rogalla, Romano, Mario, F., Schümann, F., Terrasi, and H. P., Trautvetter
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Physics ,Nuclear reaction ,Nuclear and High Energy Physics ,Physics::Instrumentation and Detectors ,Projectile ,Separator (oil production) ,Electromagnetic radiation ,Recoil separator ,Nuclear physics ,Nuclear Astrophysics ,Experimental nuclear physic ,Nuclear Experiment ,Dynamitron ,Instrumentation ,Beam (structure) ,Oxygen-16 - Abstract
For improved cross-section measurements of the reaction 12C(α,γ)16O in inverted kinematics, a recoil separator ERNA is developed at the 4MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with high efficiency. The 16O recoils are produced by the 12C projectiles in a windowless 4He gas target. We report on the pressure profile of the gas target, the beam suppression by the separator, and the first observation of the 16O recoils at selected energies. © 2003 Elsevier B.V. All rights reserved.
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- 2004
262. Astrophysical S-factor of 14N(p,)15O
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Gianluca Imbriani, F. Schümann, H. Costantini, R. Menegazzo, Gy. Gyürky, Vincenzo Roca, Pierre Descouvemont, Daniel Bemmerer, C. Rolfs, A. Guglielmetti, G. Gervino, R. Bonetti, Frank Strieder, Alberto Vomiero, P. Corvisiero, Zs. Fülöp, A. P. Jesus, A. Formicola, C. Broggini, Carmen Angulo, C. Rossi Alvarez, E. Somorjai, Sandra Zavatarelli, C. Gustavino, M. Junker, Mario R. Romano, A. Lemut, H. P. Trautvetter, Oscar Straniero, Filippo Terrasi, João Cruz, Paolo Prati, Formicola, A., Imbriani, G., Costantini, H., Angulo, C., Bemmerer, D., Bonetti, R., Broggini, C., Corvisiero, P., Cruz, J., Descouvemont, P., Fulop, Z., Gervino, G., Guglielmetti, A., Gustavino, C., Gyurky, G., Jesus, A., Junker, M., Lemut, A., Menegazzo, R., Prati, P., Roca, V., Rolfs, C., Romano, M., ROSSI ALVAREZ, C., Schumann, F., Somorjai, E., Straniero, O., Strieder, F., Terrasi, Filippo, Trautvetter, H., Vomiero, A., Zavatarelli, S., Imbriani, Gianluca, Jesus, A. P., Roca, Vincenzo, Romano, Mario, Rossi Alvarez, C., Schuemann, F., Terrasi, F., and Trautvetter, H. P.
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Physics ,Nuclear and High Energy Physics ,24.30.-v ,Solar spectra ,S-factor ,Physique ,Solar neutrino ,Direct reaction ,Resonance reaction ,CNO cycle ,Hydrostatic stellar nucleosynthesis ,Experimental physics ,Nuclear physics ,Cross section (physics) ,Globular cluster ,26.20.+f ,24.50.+g ,nuclear astrophysic ,Matrix method ,R-matrix - Abstract
We report on a new measurement of the 14N(p,γ) 15O capture cross section at Ep=140 to 400 keV using the 400 kV LUNA accelerator facility at the Laboratori Nazionali del Gran Sasso (LNGS). The uncertainties have been reduced with respect to previous measurements and their analysis. We have analyzed the data using the R-matrix method and we find that the ground state transition accounts for about 15% of the total S-factor. The main contribution to the S-factor is given by the transition to the 6.79 MeV state. We find a total S(0)=1.7±0.2 keVb, in agreement with recent extrapolations. The result has important consequences for the solar neutrino spectrum as well as for the age of globular clusters. © 2004 Elsevier B.V. All rights reserved., info:eu-repo/semantics/published
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- 2004
263. The LUNA II accelerator
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C. Gustavino, Gianluca Imbriani, D. Schürmann, A. Formicola, R. Bonetti, G. Gervino, C. Casella, H. Costantini, Sandra Zavatarelli, Vincenzo Roca, Paolo Prati, Filippo Terrasi, F. Strieder, C. Rolfs, P. Corvisiero, Carlo Broggini, Daniel Bemmerer, H. P. Trautvetter, M. Junker, Mario R. Romano, A. Lemut, A., Formicola, Imbriani, Gianluca, M., Junker, D., Bemmerer, R., Bonetti, C., Broggini, C., Casella, P., Corvisiero, H., Costantini, G., Gervino, C., Gustavino, A., Lemut, P., Prati, Roca, Vincenzo, C., Rolf, Romano, Mario, D., Schürmann, F., Strieder, F., Terrasi, H. P., Trautvetter, and S., Zavatarelli
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Nuclear reaction ,Physics ,Nuclear and High Energy Physics ,Proton ,Carbon-12 ,Resonance ,Isotopes of sodium ,Nuclear physics ,Nuclear astrophysics ,Nuclear Reactions ,Atomic physics ,Experimental nuclear physic ,Experimental Nuclear Astrophysic ,Instrumentation ,Isotopes of magnesium ,Beam (structure) - Abstract
A second high current accelerator of 400 kV has been installed at the underground laboratory of Gran Sasso, called LUNA II. We describe this new facility as well as measurements of the proton beam characteristics: absolute energy, energy spread, and long-term energy stability. The absolute energy was determined to a precision of +/-300 eV at E-p = 130-400 keV using the energy of the capture gamma-ray transition of C-12(p,gamma)N-13 as well as resonance energies at E-p = 309-389 keV of Na-23(p, gamma)Mg-24, Mg-26(p, gamma)Al-27, and Mg-25(p, gamma)Al-26. The resonance studies led to a proton energy spread of better than 100 eV and a long-term energy stability of 5 eV per hour.
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- 2003
264. The Chemical Composition of White Dwarfs as a Test of Convective Efficiency during Core Helium Burning
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Luciano Piersanti, Oscar Straniero, Gianluca Imbriani, Inma Dominguez, Straniero, O., Domínguez, I., Imbriani, Gianluca, and Piersanti, L.
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Physics ,Nuclear reaction ,Convection ,Abundance (chemistry) ,Astrophysics (astro-ph) ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Astrophysics ,Reaction rate ,Helium buring in stars ,Stars ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Stellar Evolution ,Chemical composition ,Schwarzschild radius - Abstract
Pulsating white dwarfs provide constraints to the evolution of progenitor stars. We revise He-burning stellar models, with particular attention to core convection and to its connection with the nuclear reactions powering energy generation and chemical evolution Theoretical results are compared to the available measurements for the variable white dwarf GD 358, which indicate a rather large abundance of central oxygen. We show that the attempt to constrain the relevant nuclear reaction rate by means of the white dwarf composition is faced with a large degree of uncertainty related to evaluating the efficiency of convection-induced mixing.By combining the uncertainty of the convection theory with the error on the relevant reaction rate we derive that the present theoretical prediction for the central oxygen mass fraction in white dwarfs varies between 0.3 and 0.9. Unlike previous claims, we find that models taking into account semiconvection and a moderate C12(alpha,gamma)O16 reaction rate are able to account for a high central oxygen abundance. The rate of the C12(alpha,gamma)O16 used in these models agrees with the one recently obtained in laboratory experiments (Kunz et al. 2002). On the other hand, when semiconvection is inhibited, as in the case of classical models (bare Schwarzschild criterion) or in models with mechanical overshoot, an extremely high rate of the C12(\alpha,\gamma)O16 reaction is needed to account for a large oxygen production. Finally, we show that the apparent discrepancy between our result and those reported in previous studies depends on the method used to avoid the convective runaways (the so called breathing pulses), which are usually encountered in modeling late stage of core He-burning phase., Comment: 19 pages, 4 figures, accepted for publication in The Astrophysical Journal
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- 2003
265. WEAR MEASUREMENTS BY MEANS OF RADIOACTIVE ION IMPLANTATION
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A. Stephan, Hans Werner Becker, D. Daliento, Vincenzo Roca, Gyuri Gyürky, Detlef Rogalla, Gianluca Imbriani, Lucio Gialanella, Zsolt Fülöp, N. Sanseverino, F. Strieder, Antonio D'Onofrio, Filippo Terrasi, Mario R. Romano, Michele Russo, N. De Cesare, E. Somorjai, Daliento, Santolo, Sanseverino, Annunziata, L., Gialanella, Imbriani, Gianluca, Roca, Vincenzo, M., Romano, N., Decesare, A. D., Onofrio, F., Terrasi, H. W., Becker, D., Rogalla, A., Stephan, F., Strieder, Z., Fulop, G., Gyurky, E., Somorjai, Russo, Michele, Gialanella, L., Imbriani, G., Roca, V., Romano, M., De Cesare, N., D'Onofrio, A., Terrasi, F., Becker, H. W., Rogalla, D., Stephan, A., Strieder, F., Fulop, Z., Gyurky, G., Somorjai, E., Russo, M., Daliento, D., Sanseverino, N., N., DE CESARE, A., Donofrio, D., Daiento, and A., Sanseverino
- Subjects
Materials science ,Ion beam ,business.industry ,chemistry.chemical_element ,Focused ion beam ,Ion ,Physics and Astronomy (all) ,Ion implantation ,Ion beam deposition ,chemistry ,Sputtering ,Radiation damage ,Optoelectronics ,Atomic physics ,Beryllium ,business - Abstract
Radioactive ion implantation allows non‐contacting, online wear measurements with sub micrometric sensitivity to be performed, by monitoring the removed and/or residual activity on parts subject to wear. Comparative studies of different materials, including those who exhibit a low resistance to radiation damage, can be easily performed by means of this technique. A project has started at the TTT3 tandem of the University “Federico II” in Naples, Italy, in order to exploit such technique using a 7Be ion beam, that was developed to study the astrophysical important reaction 7Be(p,γ)8B. The 7Be ion beam is produced using a ion sputter source and accelerated to an energy up to 8.0 MeV. A novel setup allows control of the implanted ion depth distribution, and is a crucial point for the application of this technique. The 7Be ion beam production and implantation procedures are discussed. Finally, the results of some test measurements are presented.
- Published
- 2002
266. A new setup for the underground study of capture reactions
- Author
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CASELLA C, COSTANTINI H, LEMUT A, LIMATA B, BEMMERER D, BONETTI R, BROGGINI C, CAMPAJOLAL, COCCONI P, CORVISIERO P, CRUZ J, FORMICOLA A, FULOP S, GERVINO G, GIALANELLA L, GUGLIELMETTI A, GUSTAVINO C, GYURKY G, IMBRIANI G, JESUS A. P, JUNKER M, ORDINE A, PARODI F, PAROLIN M, PINTO J. V, PRATI P, RIBEIRO J. P, ROCA V, ROGALLA D, ROLFS C, ROMANO M, ROSSI ALVAREZ C, SCHUMANN F, SOMORJAI E, STRANIERO O, STRIEDER F, TERRASI, Filippo, TRAUTVETTER H. P, ZAVATARELLI S., D'ONOFRIO, Antonio, C., Casella, H., Costantini, A., Lemut, B., Limata, D. BEMMERER R., Bonetti, C., Broggini, L., Campajola, P., Cocconi, P., Corvisiero, J., Cruz, A., Donofrio, A., Formicola, Z., Flp, G., Gervino, L., Gialanella, A., Guglielmetti, C., Gustavino, G., Gyurky, A., Loiano, Imbriani, Gianluca, A. P., Jesu, M., Junker, P., Musico, A., Ordine, F., Parodi, M., Parolin, J. V., Pinto, P., Prati, J. P., Ribeiro, Roca, Vincenzo, D., Rogalla, C., Rolf, M., Romano, C. R., Alvarez, A., Rottura, F., Schmann, E., Somorjai, F., Strieder, F., Terrasi, H. P. TRAUTVETTER A. VOMIERO AND S., Zavatarelli, Romano, Mario, Casella, C, Costantini, H, Lemut, A, Limata, B, Bemmerer, D, Bonetti, R, Broggini, C, Campajolal, Cocconi, P, Corvisiero, P, Cruz, J, D'Onofrio, Antonio, Formicola, A, Fulop, S, Gervino, G, Gialanella, L, Guglielmetti, A, Gustavino, C, Gyurky, G, Imbriani, G, Jesus, A. P., Junker, M, Ordine, A, Parodi, F, Parolin, M, Pinto, J. V., Prati, P, Ribeiro, J. P., Roca, V, Rogalla, D, Rolfs, C, Romano, M, ROSSI ALVAREZ, C, Schumann, F, Somorjai, E, Straniero, O, Strieder, F, Terrasi, Filippo, Trautvetter, H. P., and Zavatarelli, S.
- Published
- 2002
267. Off-line production of a 7Be radioactive ion beam
- Author
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Gialanella L, Greife U, De Cesare N, D'ONOFRIO, Antonio, Romano M, Campajola L, Formicola A, Fulop Z, Gyurky G, Imbriani G, LUBRITTO, Carmine, Ordine A, Roca V, Rogalla D, Rolfs C, Russo M, Somorjai E, Strieder F, TERRASI, Filippo, Trautvetter HP, RI Gyurky Gyorgy/F 1078 2010 Fulop Zsolt/B 2262 2008, SABBARESE, Carlo, L., Gialanella, U., Greife, N., De Cesare, A., D’Onofrio, Romano, Mario, L., Campajola, A., Formicola, Z., Fulop, G., Gyurky, Imbriani, Gianluca, C., Lubritto, A., Ordine, Roca, Vincenzo, D., Rogalla, C., Rolf, Russo, Michele, C., Sabbarese, E., Somorjai, F., Strieder, F., Terrasi, H. P., Trautvetter, Gialanella, L, Greife, U, De Cesare, N, D'Onofrio, Antonio, Romano, M, Campajola, L, Formicola, A, Fulop, Z, Gyurky, G, Imbriani, G, Lubritto, Carmine, Ordine, A, Roca, V, Rogalla, D, Rolfs, C, Russo, M, Sabbarese, Carlo, Somorjai, E, Strieder, F, Terrasi, Filippo, Trautvetter, Hp, and RI Gyurky Gyorgy/F 1078 2010 Fulop Zsolt/B 2262, 2008
- Subjects
Nuclear and High Energy Physics ,Ion beam ,Proton ,Chemistry ,Cyclotron ,Radiochemistry ,Nuclear reaction ,Ion ,law.invention ,Ion beam analysis and implantation ,Ion beam deposition ,Sputtering ,law ,Radioactive beam production ,Nuclide ,Instrumentation ,Beam (structure) - Abstract
A 7Be ion beam of several particle pA at 8 MeV has been produced at the TTT3 tandem of the University "Federico II" in Naples. The 7Be nuclides were formed via the 7Li(p,n)7Be reaction using a metallic Li target and an 11.4 MeV proton beam of 20 μA intensity, delivered by the cyclotron in Debrecen. Methods of hot chemistry were used to extract the 7Be nuclides from the Li matrix and to prepare the 7Be cathodes for the ion sputter source of the tandem. Examples of 7Be beam applications are given. © 2002 Elsevier Science B.V. All rights reserved.
- Published
- 2002
268. Stopping power of low-energy deuterons in He-3 gas
- Author
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Vincenzo Roca, M. Junker, Paolo Prati, Mario R. Romano, Gianluca Imbriani, Detlef Rogalla, Antonio D'Onofrio, H. Costantini, R.W. Kavanagh, C. Gustavino, A. Ordine, Gyuri Gyürky, Zsolt Fülöp, E. Somorjai, R. Bonetti, G. Gervino, Oscar Straniero, P. Corvisiero, Marialuisa Aliotta, A. Formicola, Filippo Terrasi, L. Campajola, A. Guglielmetti, H. P. Trautvetter, Frank Strieder, Lucio Gialanella, Carlo Broggini, F. Raiola, C. Rolfs, Sandra Zavatarelli, F. Schümann, P. G. Prada Moroni, Raiola, F, Gyurky, G, Aliotta, M, Formicola, A, Bonetti, R, Broggini, C, Campajola, L, Corvisiero, P, Costantini, H, D'Onofrio, A, Fulop, Z, Gervino, G, Gialanella, L, Guglielmetti, A, Gustavino, C, Imbriani, Gianluca, Junker, M, Kavanagh, Rw, Moroni, Pgp, Ordine, A, Prati, P, Roca, Vincenzo, Rogalla, D, Rolfs, C, Romano, Mario, Schumann, F, Somorjai, E, Straniero, O, Strieder, F., Terrasi, F, Trautvetter, Hp, and Zavatarelli, S.
- Subjects
Physics ,Experimental Nuclear Physic ,Nuclear and High Energy Physics ,Hadron ,chemistry.chemical_element ,Energy loss and stopping power ,DISSOCIATION ,HYDROGEN ,Charged particle ,Ion ,H2+ IONS ,Nuclear physics ,chemistry ,Deuterium ,Helium-3 ,VELOCITY PROPORTIONALITY ,Nuclear fusion ,Atomic physics ,HELIUM ,Isotopes of helium ,Helium - Abstract
The stopping power of atomic and molecular deuterons in 3 He gas was measured over the range Ed = 10 to 100 keV using the 3 He pressure dependence of the 3 He(d,p) 4 He reactionyield. At en ergies above 30 keV, the observed stopping power values are in good agreement with a standard compilation. However, near 18 keV the experimental values drop by a factor 50 below the extrapolated values of the compilation. In a simple model, the behavior is due to the minimum 1s → 2s electronexcitationof the He target atoms (= 19.8 eV, corresponding to Ed = 18.2 keV), i.e. it is a quantum effect, by which the atoms become nearly transparent for the ions.
- Published
- 2001
269. Direct measurement of the absolute cross section of p(7Be,γ)8B
- Author
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Vincenzo Roca, Antonio D'Onofrio, Frank Strieder, E. Somorjai, Gianluca Imbriani, C. Rolfs, Filippo Terrasi, Carmine Lubritto, Carlo Sabbarese, H. P. Trautvetter, A. Ordine, Mario R. Romano, L. Gialanella, Detlef Rogalla, L. Campajola, Uwe Greife, Gyuri Gyürky, Terrasi, F., Gialanella, L., Imbriani, G., Strieder, F., Campajola, L., D'Onofrio, A., Greife, U., Gyurky, G., Lubritto, C., Ordine, A., Roca, V., Rolfs, C., Romano, M., Rogalla, D., Sabbarese, C., Somorjai, E., Trautvetter, H. P., F., Terrasi, L., Gialanella, Imbriani, Gianluca, F., Strieder, L., Campajola, A., D'Onofrio, U., Greife, G., Gyurky, C., Lubritto, A., Ordine, Roca, Vincenzo, C., Rolf, Romano, Mario, D., Rogalla, C., Sabbarese, E., Somorjai, and H. P., Trautvetter
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,Cross section (physics) ,Solar Hydrogen Burining ,Absolute (philosophy) ,Experimantal nuclear physic ,Nuclear Astrophysic - Abstract
A new direct measurement of the absolute cross section of the 1H(7Be,γ)8B reaction has been performed in inverse kinematics at Ecm = 990 keV. A radioactive 7Be beam (Elab, = 8 MeV) and a windowless H2 gas target were used; 8B recoils were identified and counted by a recoil mass separator. The reaction cross section was derived by normalization to the elastic scattering cross section, measured in a separate run. The resulting value σr = 0.40 ± 0.12 μb yielded an astrophysical S-factor at zero energy So = 15.3 ± 4.5 eV b, in fair agreement with recommended values. © 2001 Elsevier Science B.V. All rights reserved.
- Published
- 2001
270. Electron screening effect in the reactions 3He(d,p)4He and d(3He,p)4He
- Author
-
R. Bonetti, Lucio Gialanella, C. Rolfs, Vincenzo Roca, Paolo Prati, M. Junker, Zs. Fülöp, A. Formicola, Mario R. Romano, A. Ordine, Gy. Gyürky, Gianluca Imbriani, Sandra Zavatarelli, H. P. Trautvetter, H. Costantini, P. Corvisiero, G. Gervino, Oscar Straniero, C. Gustavino, Marialuisa Aliotta, P.G. Moroni, Filippo Terrasi, A. Guglielmetti, E. Somorjai, Detlef Rogalla, Antonio D'Onofrio, Frank Strieder, L. Campajola, F. Schümann, Carlo Broggini, F. Raiola, M., Aliotta, F., Raiola, G., Gyurky, A., Formicola, R., Bonetti, C., Broggini, L., Campajola, P., Corvisiero, H., Costantini, A., D'Onofrio, Z., Fulop, G., Gervino, L., Gialanella, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, M., Junker, R. W., Kavanagh, P. G., Moroni, A., Ordine, P., Prati, Roca, Vincenzo, D., Rogalla, C., Rolf, Romano, Mario, F., Schumann, E., Somorijai, O., Straniero, F., Strieder, F., Terrasi, H. P. TRAUTVETTER AND S. Z. A. V. A. T. A. R. E. L. L., I., G., Gyürky, Z., Fülöp, F., Schümann, E., Somorjai, H. P., Trautvetter, and S., Zavatarelli
- Subjects
Experimental Nuclear Physic ,Physics ,Nuclear physics ,Nuclear and High Energy Physics ,Electron screening ,Screening effect ,Nuclear Reactions ,Nuclear astrophysics ,Electron ,Atomic physics ,Potential energy ,Dissociation (chemistry) - Abstract
The cross section of the reactions 3He(d, p) 4 He and d(3He, p)4He has been measured at the center-of-mass energies E=5 to 60 keV and 10 to 40 keV, respectively. The experiments were performed to determine the magnitude of the electron screening effect leading to the respective electron-screening potential energy U e =219±7 and 109±9 eV, which are both significantly higher than the respective values from atomic physics models, U e =120 and 65 eV.
- Published
- 2001
271. The D(He-3, p)He-4 fusion reaction: electron screening effect and astrophysical S(E) factor at low energies
- Author
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C. Rolfs, R. Bonetti, F. Strieder, Antonio D'Onofrio, P. G. Prada Moroni, Gianluca Imbriani, F. Schümann, Sandra Zavatarelli, A. Ordine, H. Costantini, M. Junker, G. Gervino, Filippo Terrasi, Mario R. Romano, Detlef Rogalla, H. P. Trautvetter, L. Campajola, Vincenzo Roca, C. Gustavino, Paolo Prati, P. Corvisiero, A. Formicola, Lucio Gialanella, Carlo Broggini, A. Guglielmetti, S., Zavatarelli, P., Corvisiero, H., Costantini, P. G., Prada Moroni, P., Prati, R., Bonetti, A., Guglielmetti, C., Broggini, L., Campajola, A., Formicola, L., Gialanella, Imbriani, Gianluca, A., Ordine, Roca, Vincenzo, Romano, Mario, A., D'Onofrio, F., Terrasi, G., Gervino, C., Gustavino, M., Junker, D., Rogalla, C., Rolf, F., Schumann, F., Strieder, and H. P., Trautvetter
- Subjects
Nuclear physics ,Physics ,Experimental Nuclear Physic ,Nuclear and High Energy Physics ,Screening effect ,Nuclear Astrophysics ,Nuclear fusion ,Electron ,Atomic physics ,E factor ,Nuclear Astrophysic ,underground laboratory - Abstract
The D(He-3,p)He-4 cross section has been measured at E = 4.2 to 13.8 keV using the LUNA accelerator facility installed in the Gran Sasso National Laboratory (LNGS). The experimental setup and the interpretation of results in terms of electron screening potential are described. In the same experiment an estimate of the observed stopping power of the He-3 ions in D-2 target has been obtained and it turned out to be in good agreement with the standard compilation.
- Published
- 2001
272. Stopping power, electron screening and the astrophysical S(E) factor of d(3He,p)4He'
- Author
-
Costantini, Heide, Formicola, A., Junker, M., Bonetti, R., Broggini, C., Campajola, L., Corvisiero, Pietro, D'Onofrio, A., Gervino, G., Gialanella, L., Greife, U., Guglielmetti, A., Gustavino, C., Imbriani, G., Ordine, A., Prati, Paolo, Roca, V., Rogalla, D., Rolfs, C., Romano, M., Schmann, F., Strieder, F., Terrasi, F., Trautvetter, H. P., Zavatarelli, Sandra, H., Costantini, A. FORMICOLA M., Junker, R., Bonetti, C., Broggini, L., Campajola, P., Corvisiero, A., D'Onofrio, G., Gervino, L., Gialanella, U., Greife, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, A., Ordine, P., Prati, Roca, Vincenzo, D., Rogalla, C., Rolf, Romano, Mario, F., Schueman, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, and S., Zavatarelli
- Published
- 2000
273. Stopping power, electron screening and the astrophysical S(E) factor of d(He-3,p)He-4
- Author
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L. Gialanella, Carlo Broggini, C. Gustavino, Gianluca Imbriani, Vincenzo Roca, Uwe Greife, A. Guglielmetti, Paolo Prati, A. Formicola, A. Fubini, F. Schumann, C. Rolfs, Detlef Rogalla, P. G. Prada Moroni, G. Gervino, A. Ordine, Oscar Straniero, Filippo Terrasi, Antonio D'Onofrio, Sandra Zavatarelli, Frank Strieder, L. Campajola, R. Bonetti, H. Costantini, P. Corvisiero, M. Junker, Mario R. Romano, H. P. Trautvetter, Costantini, H, Formicola, A, Junker, M, Bonetti, R, Broggini, C, Campajola, L, Corvisiero, P, D'Onofrio, Antonio, Fubini, A, Gervino, G, Gialanella, Lucio, Greife, U, Guglielmetti, A, Gustavino, C, Imbriani, G, Ordine, A, Moroni, Pgp, Prati, P, Roca, V, Rogalla, D, Rolfs, C, Romano, M, Schumann, F, Straniero, O, Strieder, F, Terrasi, Filippo, Trautvetter, Hp, Zavatarelli, S., H., Costantini, A., Formicola, M., Junker, R., Bonetti, C., Broggini, L., Campajola, P., Corvisiero, A., D'Onofrio, A., Fubini, G., Gervino, L., Gialanella, U., Greife, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, A., Ordine, P. G., Prada Moroni, P., Prati, Roca, Vincenzo, D., Rogalla, C., Rolf, Romano, Mario, F., Schümann, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, and S., Zavatarelli
- Subjects
Physics ,electron screening ,Nuclear and High Energy Physics ,Screening effect ,Experimental Nuclear physic ,Electron ,E factor ,Potential energy ,Ion ,Nuclear physics ,Cross section (physics) ,stopping power ,Nuclear Astrophysics ,Stopping power (particle radiation) ,Atomic physics ,Data reduction - Abstract
The d( 3 He,p) 4 He cross section has been measured at E =4.2 to 13.8 keV using the LUNA underground accelerator facility. The experiment was performed to determine the magnitude of the atomic screening effect and to establish values for the energy loss used in data reduction. The observed stopping power of the 3 He ions in the D 2 target is in good agreement with the standard compilation. Using these stopping power values the data lead to an electron-screening potential energy U e = 132±9 eV, which is significantly higher than the estimated value of 65 eV from an atomic-physics model.
- Published
- 2000
274. Energy loss of deuterons in He-3 gas: a threshold effect
- Author
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A. Guglielmetti, F. Schümann, Detlef Rogalla, Vincenzo Roca, Gianluca Imbriani, Paolo Prati, Oscar Straniero, C. Rolfs, Marialuisa Aliotta, Filippo Terrasi, Lucio Gialanella, Sandra Zavatarelli, P. Corvisiero, Gyuri Gyürky, L. Campajola, E. Somorjai, H. Costantini, Antonio D'Onofrio, A. Formicola, R. Bonetti, C. Gustavino, Carlo Broggini, F. Raiola, Frank Strieder, G. Gervino, M. Junker, Mario R. Romano, H. P. Trautvetter, A. Ordine, Zsolt Fülöp, Formicola, A., Aliotta, M., Gyürky, G., Raiola, F., Bonetti, R., Broggini, C., Campajola, L., Corvisiero, P., Costantini, H., D'Onofrio, A., Fülöp, Z., Gervino, G., Gialanella, L., Guglielmetti, A., Gustavino, C., Imbriani, Gianluca, Junker, M., Ordine, A., Prati, P., Roca, Vincenzo, Rogalla, D., Rolfs, C., Romano, Mario, Schümann, F., Somorjai, E., Straniero, O., Strieder, F., Terrasi, F., Trautvetter, H. P., Zavatarelli, S., A., Formicola, M., Aliotta, G., Gyurky, F., Raiola, R., Bonetti, C., Broggini, L., Campajola, P., Corvisiero, H., Costantini, A., D'Onofrio, Z., Fulop, G., Gervino, L., Gialanella, A., Guglielmetti, C., Gustavino, M., Junker, A., Ordine, P., Prati, D., Rogalla, C., Rolf, F., Schuemann, E., Somorjai, O., Straniero, F., Strieder, F., Terrasi, H. P., Trautvetter, and AND S., Zavatarelli
- Subjects
Physics ,NUCLEAR ASTROPHYSICS ,Experimental Nuclear Physic ,Nuclear and High Energy Physics ,Drop (liquid) ,Experimental nuclear astrophysics ,chemistry.chemical_element ,Energy loss and stopping power ,CROSS-SECTION ,Quantum Hall effect ,chemistry ,Deuterium ,Electron excitation ,Helium-3 ,Nuclear fusion ,Atomic physics ,Isotopes of helium ,Helium - Abstract
The energy loss of deuterons in 3He gas was measured at E d = 15 to 100 keV using the 3He pressure dependence of the 3He(d,p)4He cross-section at a given incident energy. At the highest energies, the observed energy loss is in good agreement with a standard compilation. However, with decreasing energy the experimental values drop steadily below the theoretical values and near E d = 18 keV they drop sharply (within 1 keV) reaching the domain of nuclear stopping power. This threshold behavior is due to the minimum 1s → 2s electron excitation of the He target atoms, i.e. it is a quantum effect. Some consequences are discussed.
- Published
- 2000
275. First measurement of the 3He(3He,2p)4He cross section down to the lower edge of the Solar Gamow peak
- Author
-
Bonetti, R., Broggini, C., Campajola, L., Corvisiero, P., D Alessandro, A., Dessalvi, M., D Onofrio, A., Fubini, A., Gervino, G., Gialanella, L., Greife, U., Guglielmetti, A., Gustavino, C., Imbriani, G., Junker, M., Prati, P., Roca, V., Rolfs, C., Romano, M., Schuemann, F., Strieder, F., Filippo Terrasi, Trautvetter, H. P., Zavatarelli, S., Bonetti, R., Broggini, C., Campajola, L., Corvisiero, P., Dalessandro, A., Dessalvi, M., D'Onofrio, Antonio, Fubini, A., Gervino, G., Gialanella, L., Greife, U., Guglielmetti, A., Gustavino, C., Imbriani, G., Junker, M., Prati, P., Roca, V., Rolfs, C., Romano, M., Schuemann, F., Strieder, F., Terrasi, Filippo, Trautvetter, H. P., Zavatarelli, S., R., Bonetti, C., Broggini, Campajola, Luigi, P., Corvisiero, A., D’Alessandro, M., Dessalvi, A., D'Onofrio, A., Fubini, G., Gervino, L., Gialanella, U., Greife, A., Guglielmetti, C., Gustavino, Imbriani, Gianluca, M., Junker, P., Prati, Roca, Vincenzo, C., Rolf, Romano, Mario, F., Schuemann, F., Strieder, F., Terrasi, H. P., Trautvetter, and S., Zavatarelli
- Subjects
Experimental Nuclear Physic ,Nuclear Astrophysic ,underground laboratory - Abstract
We give the LUNA results on the sigma(E) cross section measurement of a key reaction of the proton-proton chain strongly affecting the calculated neutrino luminosity from the Sun: He-3(He-3, 2p)He-4. Because of the cosmic ray suppression provided by the Gran Sasso underground laboratory, it has been possible to measure sigma(E) throughout the energy range in which this reaction occurs in the Sun, i.e., down to 16.5 keV center of mass energy. The data clearly show the cross section increase due to the electron screening effect but they do not exhibit any evidence for a narrow resonance suggested to explain the B-8 and Be-7 solar neutrino flux reduction.
- Published
- 1999
276. Recoil separator ERNA: Ion Beam purification'
- Author
-
C. Rolfs, H. P. Trautvetter, A. Ordine, Gianluca Imbriani, Mario R. Romano, Uwe Greife, L. Campajola, S. Theis, Frank Strieder, Vincenzo Roca, Detlef Rogalla, F. Schümann, Carlo Sabbarese, Filippo Terrasi, Antonio D'Onofrio, L. Gialanella, D., Rogalla, S., Thei, L., Campajola, A., D'Onofrio, L., Gialanella, U., Greife, Imbriani, Gianluca, A., Ordine, Roca, Vincenzo, C., Rolf, Romano, Mario, C., Sabbarese, F., Schumann, F., Strieder, F., Terrasi, H. P., Trautvetter, F., Schümann, Rogalla, D, Theis, S, Campajola, L, D'Onofrio, Antonio, Gialanella, Lucio, Greife, U, Imbriani, G, Ordine, A, Roca, V, Rolfs, C, Romano, M, Sabbarese, Carlo, Schumann, F, Strieder, F, Terrasi, Filippo, and Trautvetter, Hp
- Subjects
Nuclear reaction ,Physics ,Nuclear and High Energy Physics ,Ion beam ,Particle detector ,Semiconductor detector ,Momentum ,Nuclear physics ,Nuclear Astrophysics ,Measuring instrument ,Nuclear astrophysics ,Physics::Accelerator Physics ,Atomic physics ,Experimental nuclear physic ,Instrumentation ,Beam (structure) - Abstract
For improved measurements of the key astrophysical reaction View the MathML source in inverse kinematics, a recoil separator ERNA is developed to detect directly the View the MathML source recoils with nearly 100% efficiency. Since the View the MathML source projectiles and the View the MathML source recoils have essentially the same momentum and since the View the MathML source ion beam emerging from an accelerator usually passes through a momentum filter, a sufficient absence of an View the MathML source beam contaminant in the View the MathML source ion beam is of utmost importance for ERNA. In the present work, a Wien filter together with a ΔE−E telescope are used to investigate the beam contaminants accompanying a momentum-filtered View the MathML source ion beam and to measure the level of ion beam purification achievable with the Wien filter.
- Published
- 1999
277. LUNA: a laboratory for underground nuclear astrophysics
- Author
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F. Strieder, A. Formicola, Gianluca Imbriani, H. Costantini, M. Junker, C. Rolfs, Costantini, H., Formicola, A., Imbriani, Gianluca, Junker, M., Rolfs, C., and Strieder, F.
- Subjects
Experimental Nuclear Physic ,Physics ,Luminosity (scattering theory) ,FOS: Physical sciences ,General Physics and Astronomy ,Astronomy ,Nucleosynthesis ,Nuclear astrophysics ,Nuclear fusion ,Nuclear Experiment (nucl-ex) ,Neutrino ,Nuclear Astrophysic ,Stellar Evolution ,Nuclear Experiment ,Stellar evolution - Abstract
It is in the nature of astrophysics that many of the processes and objects one tries to understand are physically inaccessible. Thus, it is important that those aspects that can be studied in the laboratory be rather well understood. One such aspect are the nuclear fusion reactions, which are at the heart of nuclear astrophysics. They influence sensitively the nucleosynthesis of the elements in the earliest stages of the universe and in all the objects formed thereafter, and control the associated energy generation, neutrino luminosity, and evolution of stars. We review an experimental approach for the study of nuclear fusion reactions based on an underground accelerator laboratory, named LUNA., Invited Review; accepted for publication in Reports on Progress in Physics; 26 pages; 27 figures
- Published
- 2009
- Full Text
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