| Records |
| Author |
n_TOF Collaboration (Mosconi, M. et al); Domingo-Pardo, C.; Tain, J.L. |
| Title |
Neutron physics of the Re/Os clock. I. Measurement of the (n, gamma) cross sections of Os-186,Os-187,Os-188 at the CERN n_TOF facility |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
82 |
Issue |
1 |
Pages |
015802 - 10pp |
Keywords  |
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| Abstract |
The precise determination of the neutron capture cross sections of Os-186 and Os-187 is important to define the s-process abundance of Os-187 at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of Os-187 due to the decay of the unstable Re-187 (t(1/2) = 41.2 Gyr) and from this to infer the time duration of the nucleosynthesis in our galaxy (Re/Os cosmochronometer). The neutron capture cross sections of Os-186, Os-187, and Os-188 have been measured at the CERN n_TOF facility from 1 eV to 1 MeV, covering the entire energy range of astrophysical interest. The measurement has been performed by time-of-flight technique using isotopically enriched samples and two C6D6 scintillation detectors for recording the prompt. rays emitted in the capture events. Maxwellian averaged capture cross sections have been determined for thermal energies between kT = 5 and 100 keV corresponding to all possible s-process scenarios. The estimated uncertainties for the values at 30 keV are 4.1, 3.3, and 4.7% for Os-186, Os-187, and Os-188, respectively. |
| Address |
[Mosconi, M.; Domingo-Pardo, C.; Kaeppeler, F.; Audouin, L.; Bisterzo, S.; Dillmann, I.; Heil, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K.] KIT, Inst Kernphys, D-76021 Karlsruhe, Germany, Email: Marita.Mosconi@ptb.de |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000279940200007 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
409 |
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| Author |
n_TOF Collaboration (Fujii, K. et al); Domingo-Pardo, C.; Tain, J.L. |
| Title |
Neutron physics of the Re/Os clock. III. Resonance analyses and stellar (n, gamma) cross sections of Os-186,Os-187,Os-188 |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
82 |
Issue |
1 |
Pages |
015804 - 18pp |
| Keywords |
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| Abstract |
Neutron resonance analyses have been performed for the capture cross sections of Os-186, Os-187, and Os-188 measured at the n_TOF facility at CERN. Resonance parameters have been extracted up to 5, 3, and 8 keV, respectively, using the SAMMY code for a full R-matrix fit of the capture yields. From these results average resonance parameters were derived by a statistical analysis to provide a comprehensive experimental basis for modeling of the stellar neutron capture rates of these isotopes in terms of the Hauser-Feshbach statistical model. Consistent calculations for the capture and inelastic reaction channels are crucial for the evaluation of stellar enhancement factors to correct the Maxwellian averaged cross sections obtained from experimental data for the effect of thermally populated excited states. These factors have been calculated for the full temperature range of current scenarios of s-process nucleosynthesis using the combined information of the experimental data in the region of resolved resonances and in the continuum. The consequences of this analysis for the s-process component of the Os-187 abundance and the related impact on the evaluation of the time duration of galactic nucleosynthesis via the Re/Os cosmochronometer are discussed. |
| Address |
[Fujii, K.; Abbondanno, U.; Belloni, F.; Milazzo, P. M.; Moreau, C.] Ist Nazl Fis Nucl, I-34149 Trieste, Italy, Email: Kaori.Fujii@ts.infn.it |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000279940200009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
410 |
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| Author |
Rodriguez, D. et al; Algora, A.; Rubio, B.; Tain, J.L. |
| Title |
MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR |
Type |
Journal Article |
| Year |
2010 |
Publication |
European Physical Journal-Special Topics |
Abbreviated Journal |
Eur. Phys. J.-Spec. Top. |
| Volume |
183 |
Issue |
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Pages |
1-123 |
| Keywords |
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| Abstract |
Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10(-5) to below 10(-8) for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10(-9) can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e. g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with beta-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively. |
| Address |
[Rodriguez, D.; Lallena, A. M.] Univ Granada, Dept Fis Atom Mol & Nucl, E-18071 Granada, Spain, Email: danielrodriguez@ugr.es |
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Thesis |
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| Publisher |
Springer Heidelberg |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1951-6355 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000280061400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
412 |
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| Author |
BABAR Collaboration (del Amo Sanchez, P. et al); Lopez-March, N.; Martinez-Vidal, F.; Milanes, D.A.; Oyanguren, A. |
| Title |
Evidence for the decay X(3872) -> J/psi omega |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
82 |
Issue |
1 |
Pages |
011101 - 8pp |
| Keywords |
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| Abstract |
We present a study of the decays B-0,B-+ -> J/psi pi(+)pi(-)pi K-0(0,+), using 467 x 106 B (B) over bar pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) -> J/psi omega, with product branching fractions B(B+ -> X(3872K(+)) x B(X(3872) -> J/psi omega) = [0.6 +/- 0.2(stat) +/- 0.1(syst)] x 10(-5), and B(B-0 -> X(3872)K-0) x B(X(3872) -> J/psi omega) = [0.6 +/- 0.3(stat) +/- 0.1(syst)] x 10(-5). A detailed study of the pi(+) pi(-) pi(0) mass distribution from X(3872) decay favors a negative-parity assignment. |
| Address |
[del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.] Univ Savoie, Lab Annecy Le Vieux Phys Particules LAAP, CNRS, IN2P3, F-74941 Annecy Le Vieux, France |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1550-7998 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000279691200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
414 |
| Permanent link to this record |
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| Author |
Cheng, Y.; Csernai, L.P.; Magas, V.K.; Schlei, B.R.; Strottman, D. |
| Title |
Matching stages of heavy-ion collision models |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
81 |
Issue |
6 |
Pages |
064910 - 8pp |
| Keywords |
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| Abstract |
Heavy-ion reactions and other collective dynamical processes are frequently described by different theoretical approaches for the different stages of the process, like initial equilibration stage, intermediate locally equilibrated fluid dynamical stage, and final freeze-out stage. For the last stage, the best known is the Cooper-Frye description used to generate the phase space distribution of emitted, noninteracting particles from a fluid dynamical expansion or explosion, assuming a final ideal gas distribution, or (less frequently) an out-of-equilibrium distribution. In this work we do not want to replace the Cooper-Frye description, but rather clarify the ways of using it and how to choose the parameters of the distribution and, eventually, how to choose the form of the phase space distribution used in the Cooper-Frye formula. Moreover, the Cooper-Frye formula is used in connection with the freeze-out problem, while the discussion of transition between different stages of the collision is applicable to other transitions also. More recently, hadronization and molecular dynamics models have been matched to the end of a fluid dynamical stage to describe hadronization and freeze-out. The stages of the model description can be matched to each other on space-time hypersurfaces (just like through the frequently used freeze-out hypersurface). This work presents a generalized description of how to match the stages of the description of a reaction to each other, extending the methodology used at freeze-out, in simple covariant form which is easily applicable in its simplest version for most applications. |
| Address |
[Cheng, Yun; Csernai, L. P.] Univ Bergen, Inst Phys & Technol, N-5007 Bergen, Norway, Email: yun.cheng@uib.no |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000279267600002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
417 |
| Permanent link to this record |
