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Littérature scientifique sur le sujet « Experimental nuclear astrophysic »

Auteur : Grafiati

Publié le 9 mars 2023

Mis à jour le 10 mars 2023

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Articles de revues sur le sujet "Experimental nuclear astrophysic"

RAUSCHER, THOMAS. « THE PATH TO IMPROVED REACTION RATES FOR ASTROPHYSICS ». International Journal of Modern Physics E 20, n^o 05 (mai 2011) : 1071–169. http://dx.doi.org/10.1142/s021830131101840x.

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This review focuses on nuclear reactions in astrophysics and, more specifically, on reactions with light ions (nucleons and α particles) proceeding via the strong interaction. It is intended to present the basic definitions essential for studies in nuclear astrophysics, to point out the differences between nuclear reactions taking place in stars and in a terrestrial laboratory, and to illustrate some of the challenges to be faced in theoretical and experimental studies of those reactions. The discussion revolves around the relevant quantities for astrophysics, which are the astrophysical reaction rates. The sensitivity of the reaction rates to the uncertainties in the prediction of various nuclear properties is explored and some guidelines for experimentalists are also provided.

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CHAMPAGNE, A. E., et C. ILIADIS. « FIRST RESULTS FROM LENA ». Modern Physics Letters A 22, n^o 04 (10 février 2007) : 243–57. http://dx.doi.org/10.1142/s0217732307022724.

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We review the first results from the Laboratory for Experimental Nuclear Astrophysics (LENA), which is a dedicated accelerator facility for measuring reactions of astrophysical interest. We also briefly describe the facility itself and the detector system. The reactions that have been measured have relevance for both stellar evolution and for classical nova explosions.

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Shotter, A. C. « Experimental Nuclear Physics for Astrophysics ». EAS Publications Series 11 (2004) : 191–97. http://dx.doi.org/10.1051/eas:2004013.

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Wiescher, M. « Experimental Challenges in Nuclear Astrophysics ». Nuclear Physics A 751 (avril 2005) : 285–300. http://dx.doi.org/10.1016/j.nuclphysa.2005.02.110.

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Prati, Paolo. « Underground Nuclear Astrophysics : pushing direct measurements toward the Gamow window ». EPJ Web of Conferences 227 (2020) : 01015. http://dx.doi.org/10.1051/epjconf/202022701015.

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The aim of experimental nuclear astrophysics is to provide information on the nuclear processes involved in astrophysical scenarios at the relevant energy range. However, the measurement of the cross section of nuclear reactions at low energies present formidable difficulties due to the very low reaction rates often overwhelmed by the background. Several approaches have been proposed and exploited to overcome such severe obstacles: in such frame, the idea to install a low energy - high intensity ion accelerator deep underground, to gain high luminosity while reducing the cosmic ray background, brought more than 25 years ago, to the pilot LUNA experiment. LUNA stands for Laboratory for Underground Nuclear Astrophysics: in the cave under the Gran Sasso mountain (in Italy) first a 50 kV and then a 400 kV single-ended accelerator for protons and alphas were deployed and produced plenty of data mainly on reactions of the H-burning phase in stars. Recently, similar facilities have been installed and/or proposed in other underground laboratories in US and China. LUNA as well is going to make a big step forward, with a new machine in the MV range which will be able to provide intense beams of protons, alphas and carbon ions. The rationale of underground nuclear astrophysics will be presented together with the last updates on the ongoing research programs.

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Rolfs, Claus. « Data needs in experimental nuclear astrophysics ». Nuclear Physics News 4, n^o 1 (janvier 1994) : 17–20. http://dx.doi.org/10.1080/10506899408210217.

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Bardayan, D. W. « Recent Experimental Progress in Nuclear Astrophysics ». Physics Procedia 66 (2015) : 457–64. http://dx.doi.org/10.1016/j.phpro.2015.05.058.

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Aliotta, Marialuisa. « Experimental Nuclear Astrophysics in Underground Laboratories ». Nuclear Physics News 22, n^o 2 (31 mai 2012) : 13–17. http://dx.doi.org/10.1080/10619127.2012.683715.

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Cavanna, Francesca, et Paolo Prati. « Direct measurement of nuclear cross-section of astrophysical interest : Results and perspectives ». International Journal of Modern Physics A 33, n^o 09 (30 mars 2018) : 1843010. http://dx.doi.org/10.1142/s0217751x18430108.

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Stellar evolution and nucleosynthesis are interconnected by a wide network of nuclear reactions: the study of such connection is usually known as nuclear astrophysics. The main task of this discipline is the determination of nuclear cross-section and hence of the reaction rate in different scenarios, i.e. from the synthesis of a few very light isotopes just after the Big Bang to the heavy element production in the violent explosive end of massive stars. The experimental determination of reaction cross-section at the astrophysical relevant energies is extremely difficult, sometime impossible, due to the Coulomb repulsion between the interacting nuclei which turns out in cross-section values down to the fbar level. To overcome these obstacles, several experimental approaches have been developed and the adopted techniques can be roughly divided into two categories, i.e. direct and indirect methods. In this review paper, the general problem of nuclear astrophysics is introduced and discussed from the point of view of experimental approach. We focus on direct methods and in particular on the features of low-background experiments performed at underground laboratory facilities. The present knowledge of reactions involved in the Big Bang and stellar hydrogen-burning scenarios is discussed as well as the ongoing projects aiming to investigate mainly the helium- and carbon-burning phases. Worldwide, a new generation of experiment in the MeV range is in the design phase or at the very first steps and decisive progresses are expected to come in the next years.

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Frebel, Anna. « From Nuclei to the Cosmos : Tracing Heavy-Element Production with the Oldest Stars ». Annual Review of Nuclear and Particle Science 68, n^o 1 (19 octobre 2018) : 237–69. http://dx.doi.org/10.1146/annurev-nucl-101917-021141.

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Understanding the origin of the elements has been a decades-long pursuit, with many open questions remaining. Old stars found in the Milky Way and its dwarf satellite galaxies can provide answers because they preserve clean element abundance patterns of the nucleosynthesis processes that operated some 13 billion years ago, enabling reconstruction of the chemical evolution of the elements. This review focuses on the astrophysical signatures of heavy neutron-capture elements made in the s-, i-, and r-processes found in old stars. A highlight is the recently discovered r-process galaxy Reticulum II, which was enriched by a neutron star merger. These results show that old stars in dwarf galaxies provide a novel means to constrain the astrophysical site of the r-process, ushering in much-needed progress on this major outstanding question. This nuclear astrophysics research complements the many experimental and theoretical nuclear physics efforts into heavy-element formation, and also aligns with results on the gravitational-wave signature of neutron star mergers.

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Thèses sur le sujet "Experimental nuclear astrophysic"

MASHA, ELIANA. « ASTROPHYSICAL NUCLEAR REACTIONS ON NEON ISOTOPES AT LUNA ». Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/899089.

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This thesis reports the direct measurements of the 22Ne(α,γ)26Mg and 20Ne(p,γ)21Na reactions at astrophysical energies of interest. The 22Ne(α,γ)26Mg reaction competes with the 22Ne(α,n)25Mg reaction which is the main source of neutrons for the s-process in low-mass Asymptotic Giant Branch and massive stars. At temperatures T < 300 MK where the (α,γ) channel becomes dominant, the rate of the 22Ne(α,γ)26Mg reaction is influenced by several resonances studied only indirectly. The first part of this thesis concerns the direct measurement of one of these resonances, Er = 334 keV, which so far was studied only indirectly leading to six orders of magnitude range of possible values for its resonance strength. The experiment has been performed at LUNA (Laboratory for Underground Nuclear Astrophysics) using the intense alpha beam of the LUNA 400 kV accelerator and a windowless gas target combined with a high-efficiency BGO detector. In the present study, an upper limit of 4.0·10−11 eV has been determined for the resonance strength. Taking into account these results, an up-dated 22Ne(α,γ)26Mg thermonuclear reaction rate was obtained and its role on the predicted 25Mg/26Mg ratio of a 5M⊙ AGBs was investigated. The data show a decrease by a factor of 15 of the intershell 25Mg/26Mg ratio. The 20Ne(p,γ)21Na is the slowest reaction of the NeNa cycle. It determines the velocity of the cycle and defines the final abundances of the isotopes synthesized in this cycle. The uncertainties on the NeNa cycle are affected by the 20Ne(p,γ)21Na reaction rate. The main goal of the second part of this thesis was the direct measurement of the Ecm = 366 keV resonance which dominates the total rate in the temperature range between 0.2 GK and 1 GK. The measurement has been performed at LUNA using the windowless gas target and two high-purity germanium detectors placed at different positions. This measurement allowed to reduce the uncertainty on the strengths of the 366 keV resonance from 18% to 7%. These results were used to update the 20Ne(p,γ)21Na reaction rate.

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Doherty, Daniel Thomas. « Experimental studies for explosive nuclear astrophysics ». Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/18022.

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In the ejecta from ONe novae outbursts nuclei up to A~40 are observed. The 30P(p,γ)31S reaction is thought to be the bottleneck for the production of all elements heavier than sulphur. However, due to uncertainties in the properties of key proton-unbound resonances the reaction rate is not well determined. In this thesis work, excited states in 31S were populated via the 28Si(4He,n) light-ion fusion-evaporation reaction and the prompt electromagnetic radiation was then detected with the GAMMASPHERE detector array. This γ-ray spectroscopy study, and comparisons with the stable mirror nucleus 31P, allowed the determination of the 31S level structure below the proton-emission threshold and also of the key proton-unbound states for the 30P(p,γ)31S reaction. In particular, transitions from key, low-spin states were observed for the first time. This new information was then used for the re-evaluation of the 30P(p,γ)31S reaction in the temperature range relevant for ONe novae. The newly calculated rate is higher than previous estimates implying a greater flux of material processed to high-Z elements in novae. Astrophysical X-ray bursts are thought to be a result of thermonuclear explosions on the atmosphere of an accreting neutron star. Between these bursts, energy is thought to be generated by the hot CNO cycles. The 15O(α,γ)19Ne reaction is one reaction that allows breakout from these CNO cycle and into the rp-process to fuel outbursts. The reaction is expected to be dominated by a single 3/2+ resonance at 4.033 MeV in 19Ne, however, limited information is available on this key state. This thesis work reports on a pioneering study of the 20Ne(p,d)19Ne reaction in inverse kinematics performed at the Experimental Storage Ring (ESR) as a means of accessing the 4.033-MeV state in 19Ne. The unique background free, high luminosity conditions of the ESR were utilised for this, the first transfer reaction performed at the ESR. The results of this pioneering test experiment are presented along with suggestions for future measurements at storage ring facilities.

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Álvarez, Pastor José Manuel. « Focal plane detectors of a Laue lens telescope for Nuclear Astrophysics ». Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/83940.

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centenares de keV hasta unos pocos MeV), presenta un extraordinario potencial para comprender los procesos más extremos que tienen lugar en el Universo, como las explosiones estelares o los aceleradores de partículas. No obstante, a pesar de los enormes esfuerzos realizados por los observatorios de rayos gamma (en el pasado y en la actualidad), se requiere una mejora en la sensibilidad instrumental para aprovechar el enorme potencial científico contenido en este rango energético. Durante las dos últimas décadas se han buscado formas de mejorar la sensibilidad de los instrumentos, incrementando la eficiencia de los detectores y reduciendo el ruido instrumental (mediante sofisticados mecanismos de blindaje y técnicas de análisis). Con este objetivo, un enorme esfuerzo en innovación instrumental (construcción de prototipos y estudios numéricos) está siendo realizado por una comunidad creciente de científicos que se enfrentan al reto de preparar la próxima generación de telescopios de rayos gamma. En particular, son especialmente notables los avances logrados en los últimos años en el campo de la focalización de rayos gamma mediante lentes de difracción. Conceptualmente, una lente de rayos gamma reduciría drásticamente el ruido instrumental ya que concentra los fotones en un detector de pequeñas dimensiones (el ruido es proporcional al volumen del instrumento). Una lente de difracción, para observaciones en astrofísica nuclear, no es sólo un concepto teórico, sino una realidad, gracias principalmente al proyecto CLAIRE. Asimismo, el desarrollo de la tecnología para la focalización de rayos gamma ha incentivado el desarrollo de las diferentes tecnologías de detección. Un detector apropiado para el plano focal de una lente gamma, debe disponer de capacidad de imagen, proporcionar espectroscopia de alta resolución y medir la polarización de los fotones incidentes. El trabajo presentado en esta tesis comprende tanto la óptica de focalización como el detector del plano focal. Con respecto a la óptica, se presenta el ensayo realizado con el prototipo CLAIRE, mediante el cual se ha confirmado los principios de una lente de difracción. En cuanto al plano focal, esta investigación se ha desarrollado principalmente en el marco de estudio de las misiones espaciales GRI (2007) y DUAL (2010), propuestas a la ESA dentro del programa “Cosmic Vision 2015-2025”. En el marco de la misión GRI, se presenta una configuración para el detector del plano focal basado en detectores pixelados de Cd(Zn)Te, al tiempo que se investiga y desarrolla un primer prototipo de detector pixelado de CdTe. Cabe destacar que el sistema de detección propuesto fue registrado con éxito mediante una patente europea, y está siendo desarrollado para su aplicación en medicina nuclear. En relación a la propuesta DUAL, se presenta un estudio del ruido instrumental obtenido mediante simulaciones numéricas con el fin de precisar la sensibilidad del instrumento (basado en detectores de Germanio) propuesto en esta misión. Más allá de las tecnología consideradas en GRI y DUAL, una amplia variedad de detectores pueden ser explorados, bien para el plano focal de una lente de difracción o bien como sistemas de detección por sí mismos. En este sentido, se ha ampliado el espectro de tecnologías y se ha incluido un estudio sobre detectores basados en xenón líquido. En esta tesis se ha realizado un trabajo de investigación y desarrollo con tecnologías vanguardistas propuestas para la próxima generación de telescopios de rayos gamma. Esta instrumentación debe enfrentarse al reto de alcanzar la sensibilidad requerida para dar respuesta a las cuestiones aun no resultas por la astrofísica de rayos gamma en el rango de energía de las transiciones nucleares.
few MeV) has an extraordinary potential for understanding the evolving and violent Universe. In spite of the strong efforts accomplished by past and current instruments, in order to perform observations in this energy range, an improvement in sensitivity over present technologies is needed to take full advantage of the scientific potential contained in this energy range. In order to achieve higher sensitivities, γ-ray astronomy has been looking over the last decades for new ways to increase the efficiency of its instruments while reducing the background noise. With the objective of reducing or avoiding as much background as possible (through shielding mechanisms and data analysis techniques), a strong effort in innovation and design (build-up of prototypes and numerical simulations studies) is being conducted by a community facing the challenge of preparing the next generation of γ-ray telescopes. In particular, the progress achieved during the last decade on focusing optics based on Laue lenses is especially remarkable. Conceptually, a focusing telescope will reduce drastically the background noise by concentrating γ-rays onto a small size detector. Focusing γ-rays with a Laue lens is not just a theoretical concept, but a reality, mainly thanks to the development of a first prototype of Laue lens for nuclear astrophysics accomplished as part of the CLAIRE project. Moreover, the development of focusing optics during these years has also encouraged the development of new detector technologies. The focal plane detector of a focusing telescope should provide imaging capabilities, perform high-resolution spectroscopy and measure the polarization of the incident photons in order to achieve the ambitious scientific goals. The research presented in this thesis covers both main areas of a γ-rays telescope: focusing optics and focal plane detector. As far as the optics is concerned, a test of the lens CLAIRE was performed in order to confirm the principles of a Laue diffraction lens. Concerning the focal plane detector, theoretical and experimental studies with new detector technologies have been carried out. Our main research has evolved in the framework of two mission concept studies -GRI (2007) and DUAL (2010)- submitted to the ESA Calls for a Medium-size mission opportunity within the Cosmic Vision 2015-2025 program. As far as the GRI mission is concerned, a focal plane detector configuration based on Cd(Zn)Te pixelated detectors is proposed, whilst development and testing of a detector prototype is accomplished. It is noteworthy that the detector configuration was successfully registered under a European Patent and is being considered for applications in the field of nuclear medicine. Regarding the DUAL mission, simulations of the expected space radiation environment and the resulting detector activation were carried out in order to estimate the performances of the all-sky Compton telescope of DUAL (based on Germanium-strip detectors). The results show that DUAL could achieve, after two years of operation, a continuum sensitivity one order of magnitude better than any past and current observatory in the MeV energy range and up to a factor 30 of improvement with its Laue lens. Beyond the detector technology proposed for GRI and DUAL, a wide variety of technologies could be explored for the focal plane of a γ-ray lens mission as well as for a stand-alone detector. In this thesis a focal plane detector based on liquid xenon is also considered. This work faces the challenges of the next generation of γ-ray telescopes, where high performance γ-ray detectors are necessary to achieve the required sensitivity in order to answer several hot scientific topics of Gamma-ray astrophysics in the energy range of nuclear transitions.

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Depalo, Rosanna. « The neon-sodium cycle : Study of the 22Ne(p,gamma)23Na reaction at astrophysical energies ». Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424304.

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The 22Ne(p,gamma)23Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle plays a crucial role for the synthesis of the elements with mass A = 20-25 in asymptotic giant branch stars, classical novae explosions and type Ia supernovae, where hydrogen burning occurs at high temperatures. The 22Ne(p,gamma)23Na thermonuclear reaction rate is highly uncertain because of a large number of poorly known resonances lying at astrophysical energies. This thesis reports on a new experimental study of the 22Ne(p,gamma)23Na reaction. In particular, two experiments have been performed to pin down the cross section of the proton capture on 22Ne: a measurement of the resonances at proton energies below 400 keV has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Gran Sasso (Italy), while a high-precision study of the resonances between 400 and 660 keV has been performed at the Helmoltz-Zentrum Dresden-Rossendorf (Germany). For the LUNA measurement, a windowless gas target filled with enriched 22Ne was used and the gamma rays emitted in the 23Na decay were detected by two high-purity germanium detectors. The experiment performed at LUNA led to the first detection of three previously unobserved resonances. Moreover, the decay schemes of the corresponding excited states of 23Na have been extended with the observation of new transitions. The LUNA measurement also allowed to reduce the upper limits on three unobserved resonances that represent the main source of uncertainty for the reaction rate. The HZDR experiment was performed with a 22Ne solid target and two high-purity germanium detectors surrounded by BGO anti-Compton shields. The target were prepared implanting 22Ne on a tantalum backing. The implantation was performed at the 200 kV high-current implanter of Legnaro National Laboratories (Italy). To improve the precision on the strengths of the resonances between 400 and 660 keV, the well known 22Ne(p,gamma)23Na resonances at 1279 keV and 478 keV were used for normalization. This measurement allowed to reduce the uncertainty on the strengths of the 436 keV and 638.5 keV resonances up to a factor of three. Moreover, the strength of the 661 keV resonance has been revised downward by one order of magnitude. Taking into account the new results, an updated thermonuclear reaction rate has been calculated. At the temperatures of classical novae explosions, the uncertainty on the reaction rate has been reduced by about one order of magnitude compared to the literature.
La reazione 22Ne(p,gamma)23Na fa parte del ciclo neon-sodio per il bruciamento dell' idrogeno. Il ciclo neon-sodio gioca un ruolo fondamentale per la sintesi degli elementi con massa A = 20-25 nelle stelle in fase di asymptotic giant branch, nelle esplosioni di novae di tipo classico e nelle esplosioni di supernovae di tipo Ia, dove il bruciamento di idrogeno avviene ad alte temperature. In particolare, la reazione 22Ne(p,gamma)23Na è la più incerta del ciclo neon-sodio. L'incertezza sulla sezione d'urto è dovuta al contributo, alle energie di interesse astrofisico, di un gran numero di risonanze. Alcune di queste risonanze non sono mai state osservate, per altre, invece, l'intensità è conosciuta con grande incertezza. Per misurare la sezione d'urto della 22Ne(p,gamma)23Na alle energie di interesse astrofisico, due esperimenti sono stati condotti nell'ambito di questa tesi: il primo, svolto con l'apparato sperimentale di LUNA, ha permesso di esplorare le risonanze di energia inferiore a 400 keV. Il secondo, invece, è stato svolto all'Helmoltz-Zentrum Dresden-Rossendorf (HZDR), in Germania, ed ha permesso di miglirare la precisione sulle intensità delle risonanze tra 400 e 660 keV. Per la misura svolta al Gran Sasso è stato usato un bersaglio di tipo gassoso senza finestre di ingresso e i fotoni emessi nel decadimento del 23Na sono stati osservati con due rivelatori al germanio. L'esperimento svolto a LUNA ha permesso di rivelare per la prima volta tre risonanze. Per queste risonanze sono stati osservati anche nuovi modi di decadimento gamma. Questo ha permesso di ampliare gli schemi di decadimento di letteratura. Questa misura ha permesso, inoltre, di ridurre di due ordini di grandezza i limiti superiori sulle intensità di tre risonanze la cui esistenza è tuttora dubbia. Per l'esperimento svolto all'HZDR è stato utilizzato un bersaglio solido di 22Ne e due rivelatori al germanio circondati da schermi anti Compton. I target sono stati realizzati all'impiantatore da 200 kV dei Laboratori Nazionali di Legnaro impiantando il 22Ne su una targhetta di tantalio. L'intensità delle risonanze tra 400 e 660 keV è stata misurata usando come riferimento le risonanze a 1279 keV e 478 keV, che sono intense e ben note. Questo esperimento ha permesso di ridurre l'incertezza sull'intensità della risonanza a 436 keV di un fattore tre, mentre, per la risonanza a 661 keV, è stata determinata un'intensità un ordine di grandezza inferiore rispetto alla letteratura. Il rate di reazione astrofisico è stato aggiornato tenendo conto dei nuovi risultati descritti sopra. Alle temperature caratteristiche delle esplosioni di novae di tipo classico, l'incertezza sul nuovo rate è un ordine di grandezza inferiore rispetto alla letteratura.

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Kamil, Mohamed. « Spectroscopy of proton unbound states in 32Cl ». University of the Western Cape, 2019. http://hdl.handle.net/11394/6615.

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>Magister Scientiae - MSc
This project aimed to investigate proton unbound states in 32Cl using the 32S(3He; t) charge-exchange reaction. This research is relevant both in the context of nuclear structure and astrophysics. Excited states in 32Cl up to Ex 6 MeV were produced using a 50 MeV 3He++ beam from the K200 separated sector cyclotron at iThemba LABS. The triton ejectiles were mass analysed and detected at the focal plane of the K600 magnetic spectrometer. An additional segmented silicon detector array called CAKE was used to detect the unbound protons from states in 32Cl in conjunction with the tritons. In this work we looked for potential sources of isospin admixture that could explain the apparent violation of the Isobaric Multiplet Mass Equation (IMME) for the A = 32, T = 2 quintet. We also investigated the possibility of determining the 31S(p; ) reaction rate indirectly, via measurements of the partial proton widths of unbound states in 32Cl.

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Singh, Bhivek. « The design and simulation of a new experimental set up to measure nuclear level lifetimes ». University of the Western Cape, 2016. http://hdl.handle.net/11394/5659.

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>Magister Scientiae - MSc
Measurements of nuclear level lifetimes are an important aspect of experimental nuclear physics. Such measurements determine transition matrix elements for nuclear structure research and also provide the widths of relevant excited states in nuclei that are of astrophysical interest. In the latter, the measured widths are used to obtain reaction rates in main sequence stars such as the Sun and in binary-star systems where the accretion of material from one star to another provides an opportunity to study extreme stellar environments such as novae and x-ray bursts. This thesis work describes the design and simulation of a new experimental set up at iThemba LABS that will allow for highprecision femtosecond-level lifetime measurements of nuclear states using the Doppler Shift Attenuation Method (DSAM). We use the Solid Edge computer-aided design (CAD) software to design a new scattering chamber with a cooled target ladder specifically for such measurements using inverse-kinematic transfer reactions with ion implanted targets. The light charged ejectiles from the reaction will be detected with a ΔE - E silicon telescope, while Doppler shifted rays will be registered using a high-purity and 100% efficient germanium (HPGe) detector. We also describe preliminary Monte Carlo simulation codes that are being developed in a relativistically invariant framework to optimize the experimental set up and to obtain predicted lineshapes of γ rays from several astrophysically relevant states in nuclei using this experimental set up.
National Research Foundation (NRF)

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Schmidt, Konrad. « Experimente zur Entstehung von Titan-44 in Supernovae ». Forschungszentrum Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-93636.

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In dieser Diplomarbeit wurde das astrophysikalisch interessante Resonanztriplett der Reaktion 40Ca(α,γ)44Ti bei 4,5MeV untersucht. Am 3-MV-Tandetron des Helmholtz-Zentrums Dresden-Rossendorf wurden dafür die Energien von Protonen- und -Strahlen kalibriert, Anregungsfunktionen im Energiebereich der drei Resonanzen aufgenommen, vier CaOTargets aktiviert und deren Struktur mittels der Reaktion 40Ca(p,γ)41Sc überprüft. Im Felsenkeller-Niederniveaumesslabor wurde anschließend die Aktivität der Proben gemessen. Schließlich konnte die Summe der Resonanzstärken bei 4497 und 4510 keV -Energie im Laborsystem zu (12;8 2;3) eV und die Summe der Resonanzstärken des gesamten Tripletts, d.h. zusätzlich bei 4523 keV, zu (12;0 2;0) eV bestimmt werden. Bei der ersten Resonanzstärke konnte die Unsicherheit im Vergleich zur Literatur von 19% auf 18% verbessert werden. Außerdem bieten die Daten der vorliegenden Arbeit die Grundlage, zukünftig die Unsicherheiten noch erheblich weiter zu reduzieren
In this thesis the astrophysically interesting resonance triplet of the 40Ca(α ,γ)44Ti reaction at 4.5MeV has been studied. For this purpose energies of proton and beams provided by 3MVTandetron at Helmholtz-Zentrum Dresden-Rossendorf have been calibrated. Excitation functions of energy regions near the resonances and in-beam spectra of four different targets have been measured. The 40Ca(p,γ)41Sc reaction has been used to scan the structure of the activated targets. Afterwards their activity has been measured in the underground laboratory Felsenkeller Dresden. Hence the sum of resonance strengths at laboratory energies of 4497 and 4510 keV of (12:8 2:3) eV has been determined as well as the sum of the total triplet strength, including 4523 keV, of (12:0 2:0) eV. In the case of the first resonance, the uncertainty was decreased from 19% to 18 %. Furthermore the results of this work establish a basis for reaching much lower uncertainties in the future

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Howard, Meredith E. « The Joy of CEX : Sharpening the (t,³He) probe at 345 MeV for the charge-exchange knife drawer ». Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1222168015.

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Chabert, Laurent. « Etude du bruit de fond neutron induit par les muons dans l'expérience EDELWEISS-II ». Phd thesis, Université Claude Bernard - Lyon I, 2004. http://tel.archives-ouvertes.fr/tel-00007093.

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Plusieurs observations astronomiques indiquent que la densité de matière dans notre Univers est dominée par sa composante invisible. Parmi les particules pouvant constituer cette matière, le neutralino est un candidat supersymétrique favorisé. Cette thèse s'est faite dans le cadre de la collaboration EDELWEISS. Cette expérience tente de mettre en évidence l'interaction d'un neutralino avec un noyau cible. Les bolomètres utilisés par EDELWEISS associent à la détection des phonons celle des charges créées par le dépôt d'énergie. Cette double détection permet de rejeter une partie importante du bruit de fond associé aux interactions électroniques. Actuellement, les expériences utilisant des bolomètres double composante permettant une discrimination du bruit de fond sont les plus sensibles. Les sensibilités diminuent en augmentant la masse de détecteurs et bientôt ces expériences commenceront à être limitées par le bruit de fond neutron induit par les muons cosmiques résiduels. Ce travail de thèse présente une étude détaillée des interactions inélastiques des muons (d'énergie moyenne 300 GeV au Laboratoire Souterrain de Modane) et de la production de neutrons engendrés par les muons dans différents matériaux à l'aide de simulation GEANT. Cette étude s'inscrit dans le développement des simulations de l'expérience EDELWEISS-II qui prévoit à terme l'installation de 120 détecteurs germanium. Pour rendre ces simulations les plus réalistes possibles, nous intégrons les distributions caractéristiques des muons au LSM obtenues à l'aide des données du détecteur Fréjus. Les flux de neutrons produits par les muons atteignent un tel niveau que la collaboration a décidé de mettre en place un veto muon afin de signer leur passage à l'intérieur de l'expérience EDELWEISS-II. Nous développons aussi un étude expérimentale d'un scintillateur plastique qui sera le constituant principal du veto muon. L'expérience M3 (Mesure Muon Modane) permet l'identification des muons au LSM et donne accès au spectre expérimental des pertes d'énergie des muons par ionisation. Enfin, les résultats obtenus par simulation sur l'efficacité de détection du veto muon seront présentés.Plusieurs observations astronomiques indiquent que la densité de matière dans notre Univers est dominée par sa composante invisible. Parmi les particules pouvant constituer cette matière, le neutralino est un candidat supersymétrique favorisé. Cette thèse s'est faite dans le cadre de la collaboration EDELWEISS. Cette expérience tente de mettre en évidence l'interaction d'un neutralino avec un noyau cible. Les bolomètres utilisés par EDELWEISS associent à la détection des phonons celle des charges créées par le dépôt d'énergie. Cette double détection permet de rejeter une partie importante du bruit de fond associé aux interactions électroniques. Actuellement, les expériences utilisant des bolomètres double composante permettant une discrimination du bruit de fond sont les plus sensibles. Les sensibilités diminuent en augmentant la masse de détecteurs et bientôt ces expériences commenceront à être limitées par le bruit de fond neutron induit par les muons cosmiques résiduels. Ce travail de thèse présente une étude détaillée des interactions inélastiques des muons (d'énergie moyenne 300 GeV au Laboratoire Souterrain de Modane) et de la production de neutrons engendrés par les muons dans différents matériaux à l'aide de simulation GEANT. Cette étude s'inscrit dans le développement des simulations de l'expérience EDELWEISS-II qui prévoit à terme l'installation de 120 détecteurs germanium. Pour rendre ces simulations les plus réalistes possibles, nous intégrons les distributions caractéristiques des muons au LSM obtenues à l'aide des données du détecteur Fréjus. Les flux de neutrons produits par les muons atteignent un tel niveau que la collaboration a décidé de mettre en place un veto muon afin de signer leur passage à l'intérieur de l'expérience EDELWEISS-II. Nous développons aussi un étude expérimentale d'un scintillateur plastique qui sera le constituant principal du veto muon. L'expérience M3 (Mesure Muon Modane) permet l'identification des muons au LSM et donne accès au spectre expérimental des pertes d'énergie des muons par ionisation. Enfin, les résultats obtenus par simulation sur l'efficacité de détection du veto muon seront présentés.

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Anders, Michael. « S-factor measurement of the 2H(α,γ)6Li reaction at energies relevant for Big-Bang nucleosynthesis ». Forschungszentrum Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-141091.

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For about 20 years now, observations of 6Li in several old metal-poor stars inside the halo of our galaxy have been reported, which are largely independent of the stars’ metallicity, and which point to a possible primordial origin. The observations exceed the predictions of the Standard Big-Bang Nucleosynthesis model by a factor of 500. In the relevant energy range, no directly measured S-factors were available yet for the main production reaction 2H(α,γ)6Li, while different theoretical estimations have an uncertainty of up to two orders of magnitude. The very small cross section in the picobarn range has been measured with a deuterium gas target at the LUNA acceler- ator (Laboratory for Underground Nuclear Astrophysics), located deep underground inside Laboratori Nazionali del Gran Sasso in Italy. A beam-induced, neutron-caused background in the γ-detector occurred which had to be analyzed carefully and sub- tracted in an appropriate way, to finally infer the weak signal of the reaction. For this purpose, a method to parameterize the Compton background has been developed. The results are a contribution to the discussion about the accuracy of the recent 6Li observations, and to the question if it is necessary to include new physics into the Standard Big-Bang Nucleosynthesis model.

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Livres sur le sujet "Experimental nuclear astrophysic"

Particle astrophysics. Bristol, UK : Institute of Physics Pub., 2000.

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Klapdor-Kleingrothaus, H. V. Particle astrophysics. Bristol, UK : Institute of Physics Publ., 1997.

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M, Kuster, Beltrán B, Raffelt Georg G et European Organization for Nuclear Research., dir. Axions : Theory, cosmology, and experimental searches. Berlin : Springer, 2008.

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Kyrala, George A. High energy density laboratory astrophysics. Dordrecht : Springer, 2005.

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(Claudio), Spitaleri C., Rolfs Claus E et Pizzone Rosario Gianluca, dir. Fifth European Summer School on Experimental Nuclear Astrophysics, Santa Tecla, Sicily, Italy, 20-27 September 2009. Melville, N.Y : American Institute of Physics, 2010.

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Topical Seminar on Experimental Apparatus for High Energy Particle Physics and Astrophysics (6th 1996 San Miniato, Italy). Experimental apparatus for particle physics and astrophysics : Proceedings of the 6th Topical Seminar on Experimental Apparatus for Particle Physics and Astrophysics, Centro Studi 'I Cappucini' della Cassa di Risparmo di San Miniato, San Miniato al Todesco, Italy, 20-24 May 1996. Amsterdam : North-Holland, 1997.

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1941-, Chaichian M., Huitu Katri et Orava R. 1951-, dir. The First Arctic Workshop on Future Physics and Accelerators : Saariselkä, Finland, 21-26 August 1994. Singapore : World Scientific, 1995.

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Klapdor-Kleingrothaus, H. V. Non-accelerator particle physics. Bristol : Institute of Physics Pub., 1998.

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Non-accelerator particle physics. Bristol : Institute of Physics Pub., 1995.

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Chapitres de livres sur le sujet "Experimental nuclear astrophysic"

Angulo, C. « Experimental Tools for Nuclear Astrophysics ». Dans The Euroschool Lectures on Physics with Exotic Beams, Vol. III, 253–82. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-85839-3_7.

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Leleux, Pierre. « Nuclear Astrophysics Experiments with Radioactive Beams ». Dans Nuclei Far from Stability and Astrophysics, 283–93. Dordrecht : Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0708-5_24.

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Kankainen, Anu, et Stephane Goriely. « Nuclear Data and Experiments for Astrophysics ». Dans The Euroschool on Exotic Beams, Vol. VI, 141–79. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-10751-1_4.

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Wiedeking, Mathis. « Experimental Facilities at iThemba LABS and Measurements to Constrain Astrophysical Processes ». Dans Compound-Nuclear Reactions, 315–21. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-58082-7_40.

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Halloin, Hubert. « Laue diffraction lenses for astrophysics : From theory to experiments ». Dans Focusing Telescopes in Nuclear Astrophysics, 171–84. Dordrecht : Springer Netherlands, 2006. http://dx.doi.org/10.1007/978-1-4020-5304-7_18.

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Montagnani, Giovanni Ludovico. « Development of a 3” LaBr3 SiPM-Based Detection Module for High Resolution Gamma Ray Spectroscopy and Imaging ». Dans Special Topics in Information Technology, 77–82. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-62476-7_7.

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AbstractGamma radiation detection finds many applications in different fields, including astrophysics, nuclear physics and medical diagnostics. Nowadays large Lanthanum Bromide crystals coupled to Photomultiplier Tubes (PMTs) represent the state of the art for gamma detection modules, in particular for spectroscopic measurements. Nevertheless, there is an interest in substituting photomultiplier tubes with solid state photodetectors like Silicon Photomultipliers (SiPMs), owing to the latter’s significant advantages. These include insensitivity to magnetic fields, low bias voltage, compactness, fast response and mechanical robustness. The aim of this thesis work, which was carried out within the context of the GAMMA project supported by IstitutoNazionale di FisicaNucleare (INFN), is the design, development and experimental characterization of a -ray spectrometer based on large Lanthanum Bromide scintillator crystals coupled with Silicon Photomultipliers. This detector specifications are compliant with nuclear physics experiments with energies ranging from 100 keV to 20 MeV, characterized by state-of-the-art energy resolution and imaging capability, in a compact, modular and robust structure. In order to perform the readout of large scintillator crystals, a matrix of 144 Silicon Photomultipliers was designed using NUV-HD SiPMs from Fondazione Bruno Kessler (FBK). These were chosen due to their high Photon Detection Efficiency in correspondence with the peak emission wavelength of the crystal, the high cell density and low Dark Count Rate.

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Takahashi, Tadayuki. « A Si/CdTe Compton Camera for gamma-ray lens experiment ». Dans Focusing Telescopes in Nuclear Astrophysics, 317–31. Dordrecht : Springer Netherlands, 2006. http://dx.doi.org/10.1007/978-1-4020-5304-7_32.

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Liu, WeiPing. « Progress of Underground Nuclear Astrophysics Experiment JUNA in China ». Dans Springer Proceedings in Physics, 235–39. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13876-9_39.

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Guardo, G. L., D. Balabanski, S. Chesneyskaya, M. La Cognata, D. Lattuada, C. Matei, T. Petruse et al. « Nuclear AstroPhysics at ELI-NP : Preliminary Experiments with ELISSA Detector ». Dans Springer Proceedings in Physics, 219–23. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13876-9_36.

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Rebel, H. « Various Problems of Nuclear Astrophysics Approached by Coulomb Dissociation Experiments ». Dans NATO ASI Series, 359–67. Boston, MA : Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2568-4_48.

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Actes de conférences sur le sujet "Experimental nuclear astrophysic"

Iliadis, Christian, Claudi Spitaleri, Claus Rolfs et Rosario G. Pizzone. « Introduction to Nuclear Astrophysics ». Dans FIFTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS. AIP, 2010. http://dx.doi.org/10.1063/1.3362604.

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Kubono, Shigeru. « Nuclear Clusters in Astrophysics ». Dans VI European Summer School on Experimental Nuclear Astrophysics. Trieste, Italy : Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.148.0036.

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Kubono, Shigeru, Claudi Spitaleri, Claus Rolfs et Rosario G. Pizzone. « Nuclear Cluster Aspects in Astrophysics ». Dans FIFTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS. AIP, 2010. http://dx.doi.org/10.1063/1.3362557.

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Fujita, Yoshitaka. « Weak interaction in nuclear astrophysics ». Dans VI European Summer School on Experimental Nuclear Astrophysics. Trieste, Italy : Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.148.0031.

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Trache, Livius. « Decay spectroscopic for nuclear astrophysics ». Dans VI European Summer School on Experimental Nuclear Astrophysics. Trieste, Italy : Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.148.0033.

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Trache, Livius, Claudi Spitaleri, Claus Rolfs et Rosario G. Pizzone. « Indirect Methods For Nuclear Astrophysics With Radioactive Nuclear Beams ». Dans FIFTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS. AIP, 2010. http://dx.doi.org/10.1063/1.3362561.

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Trache, Livius. « The ANC method in nuclear astrophysics ». Dans VI European Summer School on Experimental Nuclear Astrophysics. Trieste, Italy : Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.148.0030.

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Guglielmetti, Alessandra. « Nuclear astrophysics at LUNA : recent results ». Dans VI European Summer School on Experimental Nuclear Astrophysics. Trieste, Italy : Sissa Medialab, 2013. http://dx.doi.org/10.22323/1.148.0057.

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Utsunomiya, Hiroaki. « Laser-Compton backscattering for nuclear astrophysics ». Dans SEVENTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS : Proceedings of the 7th European Summer School on Experimental Nuclear Astrophysics. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4875298.

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Barbui, M., W. Bang, A. Bonasera, K. Hagel, K. Schmidt, H. Zheng, R. Burch et al. « A laser application to nuclear astrophysics ». Dans SEVENTH EUROPEAN SUMMER SCHOOL ON EXPERIMENTAL NUCLEAR ASTROPHYSICS : Proceedings of the 7th European Summer School on Experimental Nuclear Astrophysics. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4875305.

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