exotic nuclei structure and reaction noyaux exotiques ... - IPN - IN2P3

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Lifetime measurement of first 2 + state in 74 Zn IPNO Participation: B. Mouginot, M. Niikura, M. Assié, F. Azaiez, S. Franchoo, F. Ibrahim, J. A. Scarpaci, I. Stefan D. Verney, I. Matea Collaboration : Institut fur Kernphysik, Darmstald (Germany), Universitaet zu Koeln, Cologne (Germany), CSNSM (France), GANIL (France), Laboratori Nazionali di Legnaro (Italy), NIPNE Bucarest (Romania), Institute of Nuclear Research Debrecen (Hungary), University of Sofia (Bulgaria), Flerov Laboratory Dubna (Russia) Les noyaux riches en neutrons autour de 78 Ni sont actuellement intensément étudiés par des équipes de physique et astrophysique nucléaire de part le monde. Nous rapportons ici la mesure du temps de vie des états excités dans les isotopes de 72, 73, 74 Zn par la technique du PLUNGER différentiel. Ces mesures nous permettront de contraindre les modèles nucléaires et de répondre aux questions liées au caractère magique du 78 Ni. Introduction The neutron-rich isotopes in the vicinity of 78 Ni are in the focus of modern nuclear physics and astrophysics studies [1-7]. This is a report on the lifetime measurement of exited states in neutronrich Zn isotopes using differential PLUNGER technique with the aim of constraining models that tend to predict the degree of magicity of 78 Ni. Experiment description The experiment was performed at the GANIL facility. The primary beam used was 76 Ge at 60 A.MeV. Maximum intensity used was 2 eµA. The secondary 74 Zn beam at 30 MeV was produced in the CLIM target and selected using LISE spectrometer [11] and delivered on the PLUNGER device placed in the first image focal point of the spectrometer – D4. The beam impinging on the target contained 75% 74 Zn, 20% 73 Zn and 5% 72 Cu. PLUNGER device consisted in 30 mg/cm 2 CD 2 target and 55 mg/cm 2 Be degrader. two rings around the target, first at 45° and second at 135° compared with the beam direction. The reaction products were transmitted to the end of the spectrometer, D6, were the products impinge on a (dE,E) system. For a precise time of flight (ToF) measurement, two MCP (Multichannel plate) were used, one placed in front of the PLUNGER device, second in front of the (dE,E) system. The ToF measurement allows an accurate velocity measurement for the nuclei traveling between the PLUNGER degrader and and the (dE,E) system. The velocity of the reaction products is necessary for Doppler correction of the measured gamma decay in EXOGAM detectors. For PLUNGER calibration purposes the 30+ charge state of the primary beam was selected The distance between the target and the degrader Fig. 2: Background subtracted gamma spectra measured at 45° (upper image) and 135° compared with beam direction. We see gamma lines from 72,73,74 Zn. Fig. 1: The Cologne PLUNGER device could be changed between 0 – 40 mm with a 10 um precision. The target was surrounded by eight EXOGAM clovers. The detectors were placed in with the LISE spectrometer and sent on the target. This allowed for the lifetime measurement of the first 2+ state in 76 Ge. The center-of-mass gamma spectra corrected for the velocity of 74 Zn are shown in Fig. 2. The spectra were obtained when the target and degrader were touching eachother. We clearly see 17
the 605.9 keV line of the 74 Zn 2+ to gs transition, the 449.6 keV line from 73 Zn 3/2- to gs transition and a 653. keV line identified as 72 Zn 2+ to gs transition. In order to obtain these spectra a background subtraction was necessary. The background in this experiment can be divided in two type: prompt and random. The random background originate from room background, and beta decay of the secondary beam stopped on the collimator slits placed at 2 m in front of the PLUNGER target. The prompt background is mainly composed of 511 keV line and gamma originating from (n,n' gamma) reactions in the germanium detectors. The neutrons who interact with the germanium detectors are produced from the breakup of the deuterium found in the target and from the fusion-evaporation reactions induced by secondary beam impinging the target and degrader. Using the data obtained for 562,93 keV line from 76 Ge in this experiment the lifetime extracted for 76 Ge 2+ state is consistent with the tabulated value of 26.27(29) ps [12]. The distance between the target and degrader used are 1.2, 1.5, 3.0 and 20 mm. The data for 74 Zn are under analysis. In the literature the values extracted from Coulomb excitation measurements supposing an quadrupole moment equal with 0 are 24.8(20) ps [13] and 24.5 (17) ps [14]. References [1] R. Broda et al., Phys. Rev. Lett. 74, 868 (1995) [2] R. Grzywacz et al., Phys. Rev. Lett. 81, 766 (1998) [3] H. Grawe, Nucl. Phys. A704, 211c (2002) [4] M. Sawicka et al., Phys. Rev. C 68, 044304 (2003) [5] T. Ishii et al., Phys. Rev. Lett. 84, 39 (2000) [6] O. Sorlin et al., Phys. Rev. Lett. 88, 092501 (2002) [7] K. Langanke et al., Phys. Rev. C67, 044314 (2003) [8] T. Otsuka et al., Phys. Rev. Lett. 87, 082502 (2001) [9] T. Otsuka et al., Phys. Rev. Lett. 95, 232502 (2005) [10] H. Grawe, Springer Lect. Notes in Phys. 651, 33 (2004) [11] J.P. Dufour et al., NIM A 248, 267 (1986) [12] R. Lecomte Phys. Rev. C 22, 1530–1533 (1980) [13] J. Van de Walle et al. Phys. Rev. C 79, 014309 (2009) [14] O. Perru et al. Phys. Rev. Lett. 96, 232501 (2006) 18
Page 1 and 2: EXOTIC NUCLEI STRUCTURE AND REACTIO
Page 3 and 4: in the spectra by analyzing their t
Page 5 and 6: were taken from ref. [5]. Concernin
Page 7: keV -ray with the particles and the
Page 11 and 12: Figure 2 a n d analysis. Figure 2 s
Page 13 and 14: ing particles was thus obtained by
Page 15 and 16: First p-p p collisions in the ALICE
Page 17 and 18: Quarkonia physics with ALICE IPNO P
Page 19 and 20: NA50 updated puzzle IPNO Participat
Page 21 and 22: Status of the HADES experiment (I):
Page 23 and 24: Status of the HADES experiments (II
Page 25 and 26: Status of the HADES experiment (III
Page 27 and 28: Hadron physics in pbar-p p annihila
Page 29 and 30: Hadron Electrodynamics IPNO Partici
Page 31 and 32: G0 experiment at Jefferson Lab. IPN
Page 33 and 34: GEp-III and GEp-2 at Jefferson Lab
Page 35 and 36: Exotic low mass narrow baryons from
Page 37 and 38: The PVA4 parity violation experimen
Page 39 and 40: Etude des Distributions de Partons
Page 41 and 42: Latest Results from GRAAL IPNO Part
Page 43 and 44: Persistence of the Polarization in
Page 45 and 46: The northern site of the Pierre Aug
Page 47 and 48: The Pierre Auger southern Observato
Page 49 and 50: In figure 4 we plot the differentia
Page 51 and 52: THEORETICAL PHYSICS Research in the
Page 53 and 54: transfer reaction, the 34 Si(d, 3 H
Page 55 and 56: Collective excitations with SKYRME
Page 57 and 58: Pairing and nuclear incompressibili
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Pairing properties in nuclei and in
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Evaporation-residue residue cross s
Page 63 and 64:
Extending the VMI model: normal and
Page 65 and 66:
Alpha particle condensation in nucl
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Collective Modes in Ultracold Trapp
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Exploring key unknown neutrino prop
Page 71 and 72:
Relic astrophysical and cosmologica
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After a term by term Borel resummat
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Chiral expansions of the π 0 lifet
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IPNO Participation: H. Sazdjian Eff
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fer is used to extract f + (0). We
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cleon. The spectrum becomes strongl
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A pseudo Coulombian potential in D=
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The many-body problem with an energ
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The rotational spectrum and the att
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Z-identification of very heavy nucl
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The Pegase project, a new solid sur
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But at 80 keV total energy ( 200 eV
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Isospin effects on fragment and par
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Radial collective energy and fragme
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Latent heat of the phase transition
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Alpha-particle particle condensatio
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Fluo X: Deexcitation time measureme
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ENERGY AND ENVIRONMENT The increasi
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toe/cap/y which energy access inequ
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nides. A global comparison can be p
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3D coupling of Monte-Carlo neutroni
Page 113 and 114:
Fission cross sections of actinides
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Studies and synthesis of specific m
Page 117 and 118:
Chemistry and Electrochemistry of T
Page 119 and 120:
function of temperature. The recent
Page 121 and 122:
global electron number of the redox
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(D 0 /D)-1 ln complexes of Pa(V). I
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exotic nuclei structure and reaction noyaux exotiques ... - IPN - IN2P3

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