共查询到20条相似文献,搜索用时 62 毫秒
1.
A. Korgul W. Urban T. Rząca-Urban M. Rejmund J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley N. Schulz M. Bentaleb E. Lubkiewicz I. Ahmad L.R. Morss 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):167-176
Excited states in the neutron-rich, N=84 nuclei 134Sn, 136Te and 138Xe, populated in the spontaneous fission of 248Cm, were studied to medium spins using the EUROGAM2 array. OXBASH code calculations support the experimental identification
of maximum aligned configurations in these isotopes. Empirical shell model calculations agree with the proposed excitation
energy of the neutron h9/2 excitation in the 132Sn region. A discrepancy between the observed and calculated excitation energy of the Iπ= 12+ level in 136Te indicates possible admixtures of collective excitations in this nucleus. Clear signs of collective excitations are observed
in 138Xe.
Received: 10 November 1999 / Revised version: 22 December 1999 相似文献
2.
D. Sohler J. Cederkäll Z. Dombrádi J. Persson B. Cederwall A. Johnson L.-O. Norlin M. Weiszflog A. Atac J. Blomquist R.A. Bark A. Kerek W. Klamra J. Kownacki M. Lipoglavšek S. Mitarai J. Nyberg H.A. Roth G. Sletten 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):209-211
The neutron deficient nucleus 108Te was studied in the 54Fe(58Ni,2p2n) reaction. A detector system consisting of 4 Euroball cluster detectors, a charged-particle detector ball and a 16
element neutron multiplicity filter was used to detect the emitted particles and γ rays. A new, significantly extended level
scheme was constructed on the basis of γγ-coincidence relations. Spin values for the states were determined from angular distribution
ratios. The experimental results are discussed in terms of the shell model.
Received: 7 September 1998 相似文献
3.
P. Bhattacharyya C.T. Zhang P.J. Daly B. Fornal Z.W. Grabowski I. Ahmad T. Lauritsen L.R. Morss W. Urban A. Nowak W.R. Phillips J.L. Durell M.J. Leddy A.G. Smith B.J. Varley N. Schulz E. Lubkiewicz M. Bentaleb J. Blomqvist 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):109-110
By analysis of fission product γ-ray data measured at Eurogam II using a 248Cm source, yrast levels up to about 2 MeV in the N=84 three-particle nucleus 135Sb have been identified. These levels are interpreted as π g7/2ν f7/2
2 and π g7/2ν f7/2h9/2 states with the help of shell model calculations using empirical nucleon-nucleon interactions.
Received: 30 July 1998 相似文献
4.
T. Bäck B. Cederwall R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):391-397
High-spin states in 88Mo were studied using the Gammasphere germanium detector array in conjunction with the Microball CsI(Tl) charged-particle
detector system. Three γ-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational
bands observed in the neighbouring A= 80 region have been identified and assigned to the nucleus 88Mo. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole
deformation of β2≈ 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total
routhian surface calculations. All three bands are assigned to two-quasi-particle proton configurations at superdeformed shape.
Received: 20 May 1999 / Revised version: 25 August 1999 相似文献
5.
R.P. Singh R.K. Bhowmik S.S. Ghugre S.B. Patel 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):35-40
High spins states in 99Rh were populated via the 66Zn(37Cl, 2p2n)99Rh reaction at an incident beam energy of 130 MeV. Seventeen new transitions have been observed in the present study and the
level scheme has now been extended up to a spin of J∼ 25ħ and an excitation energy of about E
x∼ 10 MeV. The observation of a positive parity E2 cascade based on the 9/2+ isomeric level is suggestive of collective behaviour in this nucleus up to high spins. Spherical shell model (within restricted
model space) and Cranked shell model calculations were performed to obtain an insight into the observed level structure. The
new collective band observed up to a spin of J∼ 25ħ is suggested to be based on (πg
9/2
3) ⊗ (νg
7/2
2) quasi-particle excitations.
Received: 12 July 1999 / Revised version: 14 September 1999 相似文献
6.
F.G. Kondev M.A. Riley T.B. Brown R.M. Clark M. Devlin P. Fallon D.J. Hartley I.M. Hibbert D.T. Joss D.R. LaFosse R.W. Laird F. Lerma M. Lively P.J. Nolan N.J. O'Brien E.S. Paul J. Pfohl D.G. Sarantites R.K. Sheline S.L. Shepherd J. Simpson R. Wadsworth 《The European Physical Journal A - Hadrons and Nuclei》1998,2(3):249-251
The quadrupole moment for the πg
9/2⊗νh
11/2 band in the 130>Pr nucleus has been measured using the Doppler-shift attenuation method. A centroid shift analysis was carried out and a value
of Q0=6.1±0.4 eb, corresponding to an axial prolate deformation of β2=0.35(3), has been determined. This is the first direct experimental confirmation of the deformation-driving character of
the πg
9/2 orbital in an odd-odd nucleus in the A≃135 superdeformed region.
Received: 23 April 1998 相似文献
7.
J. Ekman D. Rudolph C. Fahlander R.J. Charity W. Reviol D.G. Sarantites V. Tomov R.M. Clark M. Cromaz P. Fallon A.O. Macchiavelli M. Carpenter D. Seweryniak 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):13-17
Eighteen previously unknown γ-ray transitions were identified in the T
z = - 1/2 nucleus 51Fe following the fusion-evaporation reaction 32S(28Si,2α1n)51Fe. The level scheme reaches the fully aligned I
π = 27/2- terminating state of the five holes in the f
7/2 shell. The 17/2- state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of 51Fe and 51Mn is discussed, and the level scheme of 51Fe is compared to shell-model calculations.
Received: 20 July 2000 / Accepted: 1 August 2000 相似文献
8.
A.A. Pasternak J. Srebrny A.D. Efimov V.M. Mikhajlov E.O. Podsvirova Ch. Droste T. Morek S. Juutinen G.B. Hagemann M. Piiparinen S. Törmänen A. Virtanen 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):435-448
Lifetimes of excited states in 118Te have been measured using the Doppler Shift Attenuation (DSA) and Recoil Distance (RD) methods in the 109Ag(13C, p3n) reaction at a beam energy of 54 MeV. Lifetime values of the ground-state band levels with spins I
π = 2+-16+ have been obtained. The excitation energies and B(E2) values are interpreted in the framework of a version of IBFM ( IBM + 2qp) with the maximum boson number exceeding its standard
value. A satisfactory agreement with experimental level scheme and B(E2) values for the ground-state band is achieved.
Received: 7 June 2001 / Accepted: 7 February 2002 相似文献
9.
D.Q. Fang W.Q. Shen J. Feng X.Z. Cai H.Y. Zhang Y.G. Ma C. Zhong Z.Y. Zhu W.Z. Jiang W.L. Zhan Z.Y. Guo G.Q. Xiao J.S. Wang J.Q. Wang J.X. Li M. Wang J.F. Wang Z.J. Ning Q.J. Wang Z.Q. Chen 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):335-339
Measurements of reaction cross-sections ( σR's) for some proton-rich nuclei ( N = 11–15 isotones) on carbon target at intermediate energies have been performed on RIBLL of HIRFL. A larger enhancement of
the σR for 27P has been observed than for its neighboring nuclei. A large difference between the proton and neutron density distributions
(proton halo) is necessary to explain the enhanced cross-section for 27P within the framework of the Glauber model. Density distributions with HO-type core plus Yukawa-square tail and rms radii
for 27P have been deduced from the measured σR data for the first time, which conform the long tail in its densities as predicted by RMF calculations.
Received: 23 May 2001 / Accepted: 7 November 2001 相似文献
10.
P. Mohr 《The European Physical Journal A - Hadrons and Nuclei》2007,34(1):23-28
α-decay half-lives for 104, 105, 106Te and 108, 109, 110Xe close above the doubly-magic 100Sn are calculated from systematic double-folding potentials. The derived α preformation factors are compared to results for
212, 213, 214Po and 216, 217, 218Rn above the doubly-magic 208Pb. α-decay energies of Q
α = 5.42±0.07MeV and 4.65±0.15MeV are predicted for 104Te and 108Xe; the corresponding half-lives are T
1/2 ≈ 5ns for 104Te and of the order of 60μs for 108Xe. Additionally, the properties of rotational bands in 104Te are analyzed, and the first excited 2+ state in 104Te is predicted at E
x = 650±40keV; it decays preferentially by γ emission with a reduced transition strength of 10 Weisskopf units to the ground
state of 104Te and with a minor branch by α emission to the ground state of 100Sn. 相似文献
11.
D. Rudolph C. Baktash M.J. Brinkman M. Devlin H.-Q. Jin D.R. LaFosse L.L. Riedinger D.G. Sarantites C.-H. Yu 《The European Physical Journal A - Hadrons and Nuclei》1999,4(2):115-145
High-spin states of nuclei near doubly magic 56Ni were studied with the reaction 28Si(36Ar,xpynzα) at 136 MeV beam energy. The Gammasphere array in conjunction with the 4π charged-particle detector array Microball and
neutron detectors were used to detect γ rays in coincidence with evaporated light particles. The resulting extensive decay
schemes of 54Fe, 54,55Co, 56,57Ni, and 58Cu are compared to shell model calculations in the fp shell.
Received: 19 September 1998 / Revised version: 27 November 1998 相似文献
12.
W. Męczyński P. Bednarczyk R. Chapman S. Courtin J. Grębosz F. Hannachi P. Jones J. Kownacki M. Lach A. Lopez-Martens K.H. Maier J.C. Merdinger D. Middleton M. Palacz M.B. Smith K.M. Spohr N. Schulz M. Ziębliński J. Styczeń 《The European Physical Journal A - Hadrons and Nuclei》1998,3(4):311-312
The neutron deficient 199At nucleus has been studied in the 175Lu+28Si reaction at Eb= 141 MeV. In order to select events of interest in the presence of the very strong background caused by fission, γ-rays have
been detected in coincidence with recoiling evaporation residues. The excited states of 199At observed for the first time may indicate that this nucleus is deformed.
Received: 17 September 1998 / Revised version: 14 October 1998 相似文献
13.
L. Käubler H. Schnare R. Schwengner P. von Brentano F. Dönau J. Eberth J. Enders A. Fitzler C. Fransen M. Grinberg E. Grosse R.-D. Herzberg H. Kaiser P. von Neumann-Cosel N. Pietralla H. Prade A. Richter S. Skoda Ch. Stoyanov H.-G. Thomas H. Tiesler D. Weisshaar I. Wiedenhöver 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):15-18
A nuclear resonance fluorescence experiment on 88Sr has been performed with bremsstrahlung of 6.7 MeV endpoint energy. The γ-ray linear polarisation has been measured with
a EUROBALL CLUSTER detector used as a Compton polarimeter. The results indicate positive parity for the J= 1 state at 4.742
MeV in 88Sr, in contrast to the previous interpretation as a 1− two-phonon (2+
1⊗ 3−
1) state and in conflict with the predictions of the quasiparticle-phonon model. On the basis of such calculations the 1+ state at 3.486 MeV may be considered as the 1+
1 one-phonon state and the very strong 1+
1→ 0+
1 deexcitation as proton spin-flip 2p1/2→ 2p3/2 transition.
Received: 3 November 1999 相似文献
14.
C. Foin F. Farget A. Gizon D. Santos D. Barnéoud J. Genevey J. Gizon P. Paris M. Ashgar A. Płochocki 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):149-153
The high-spin level structure of the 153Er nucleus has been reinvestigated by in-beam γ-ray and electron spectroscopy with (14N,pxn) reaction. Excitation energies, spin and parity assignments are unambiguously established for the two lowest isomers
T
1/2≃ 380 ns and T1/2\simeq 10 ns. The characteristics of the third one (T
1/2≃ 250 ns) at 5.2 MeV are still questionable but its main decay modes are better known. An extension of the level scheme is
proposed up to 8.4 MeV.Experimental results have been discussed in terms of shell model multiplets and compared with the other
structures observed in N=85 neighbouring nuclei.
Received: 8 November 1999 / Revised version: 13 December 1999 相似文献
15.
J. Genevey J.A. Pinston H. Faust C. Foin S. Oberstedt B. Weiss 《The European Physical Journal A - Hadrons and Nuclei》2000,7(4):463-465
The decay of the 17 μs isomer of 133Sb was re-investigated experimentally. It was produced by thermal neutron induced fission of 241Pu. Its detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer at ILL (Grenoble),
and the γ-rays, and conversion electrons from the isomer. The interpretation of the level scheme is based on shell model calculations,
where empirical two-body matrix elements were employed. The good agreement between theory and experiment suggests that the
isomer is the 21/2+ member of the 2p-1h πg
7/2ν(f
7/2
h
11/2
−1) configuration.
Received: 20 January 2000 / Revised version: 28 February 2000 相似文献
16.
J. Timár A. Gizon P. Paris J. Genevey J. Gizon F. Hannachi C.F. Liang A. Lopez-Martens J.C. Merdinger B.M. Nyakó B. Weiss L. Zolnai 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):7-10
High spin states of 126La have been populated using the reaction 116Sn+14N at 68 MeV. γ-rays and conversion electrons were detected with the GAREL array. Multipolarities of the lowest-lying in-band
dipole transitions have been determined from the deduced internal conversion coefficients. Experimental B(M1)/B(E2) ratios
have been derived for the bands and compared with calculated values using the D?nau-Frauendorf geometrical model. Configurations
are proposed for the bands comparing them with cranked shell model calculations and on the basis of the measured B(M1)/B(E2)
ratios. The β-decay of 126La has also been revisited. The population of the 126Ba levels gives a probable spin value of five for the decaying high-spin 126La state with T
1/2≈ 64 s which may indicate a signature inversion in the πh11/2νh11/2 band.
Received: 12 October 1999 相似文献
17.
J. Timár J. Gizon A. Gizon L. Zolnai B.M. Nyakó G. Căta-Danil D. Bucurescu A.J. Boston D.T. Joss E.S. Paul A.T. Semple N.J. O'Brien C.M. Parry A.V. Afanasjev I. Ragnarsson 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):11-15
High spin states of 101Rh have been populated using the reaction 70Zn+36S at 130 MeV. γ-rays were detected with the EUROGAM2 array. New high-spin bands have been observed in this nucleus up to 45/2−, 57/2− and 65/2+ states. They have been interpreted using the Nilsson-Strutinsky cranking formalism as terminating configurations. Two of
the bands were observed up to the predicted terminating states which are built up from g9/2 protons as well as d5/2, g7/2 and h11/2 neutrons relative to a 90Zr core.
Received: 30 October 1998 相似文献
18.
C. Wheldon P.M. Walker R. D'Alarcao P. Chowdhury C.J. Pearson E.H. Seabury I. Ahmad M.P. Carpenter D.M. Cullen G. Hackman R.V.F. Janssens T.L. Khoo D. Nisius P. Reiter 《The European Physical Journal A - Hadrons and Nuclei》1999,5(4):353-355
A t
1/2 > 1 ms, high-K isomeric state feeding a strongly coupled rotational band has been identified following the deep inelastic
reaction 238
92U +186
74W at 1600 MeV. Examination of γ-ray and X-ray data combined with a g-factor analysis derived from in-band branching ratios
suggests the assignment of the new states to the neutron-rich nucleus 185
73Ta.
Received: 11 May 1999 相似文献
19.
Yu.N. Lobach A.D. Efimov A.A. Pasternak 《The European Physical Journal A - Hadrons and Nuclei》1999,6(2):131-140
Lifetimes of excited states in 110Cd have been measured by the Doppler shift attenuation method in the reaction (α,2nγ) at E
α= 25 MeV. Lifetime values for 8 states and lifetime limits for 3 states were obtained. The band structures of 110Cd have been interpreted in terms of a modified version of the interacting boson model (IBM + 2 q.p.). The calculations explain
well the excitation energies and electromagnetic transition probabilities up to J
π= 16+, except for the 10+
1 state. The structural features are discussed in terms of collective and two quasiparticle excitations.
Received: 20 March 1999 / Revised version: 28 May 1999 相似文献
20.
J. Genevey J.A. Pinston H. Faust C. Foin S. Oberstedt M. Rejmund 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):191-195
In this work we have identified and studied the decay of two new microsecond isomers 19/2- and 23/2+ in 131Sb. This neutron-rich nucleus was produced by thermal neutron-induced fission of 241Pu. The detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer at ILL (Grenoble)
and the γ-rays or conversion electrons from isomers. These new data on high-spin states complete the level scheme previously
obtained from β-decay. A large fraction of the members of the πg
7/2ν(h
11/2
-1
d
3/2
-1) and πg
7/2νh
11/2
-2 multiplets are now known and were compared with a multi-particle shell model calculation.
Received: 7 June 2000 / Accepted: 19 September 2000 相似文献