共查询到20条相似文献,搜索用时 15 毫秒
1.
J. Wrzesiński K.H. Maier R. Broda B. Fornal W. Królas T. Pawłat D. Bazzacco S. Lunardi C. Rossi Alvarez G. de Angelis A. Gadea J. Gerl M. Rejmund 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):259-265
High-spin states in 208Pb have been studied by γ-ray-spectroscopy methods in deep inelastic reactions induced by beams of 208Pb, 136Xe and 76Ge beams on a thick 208Pb target. The 11+
2 state and new γ-transitions between the one-particle one-hole states of highest spin have been found and electromagnetic
matrix elements verified. High-spin states of two-particle two-hole structure have been detected for the first time. The results
are compared to shell model calculations with realistic interactions in the complete Kuo-Herling space.
Received: 31 October 2000 / Accepted: 26 March 2001 相似文献
2.
An effective residual interaction between particles and holes for shell model calculations around 208Pb, derived from the interaction between free nucleons, is compared with the measured properties of proton-hole neutron states
in 208Tl and the interaction between proton holes is adjusted to newly measured level energies in 206Hg. These interaction elements are particularly relevant for neutron-rich nuclei. The adjustment of two mixing elements reproduces
the known γ-decay data in 208Tl.
Received: 2 April 2002 / Accepted: 2 May 2002 相似文献
3.
M. Rejmund K. H. Maier R. Broda B. Fornal M. Lach J. Wrzesiński J. Blomqvist A. Gadea J. Gerl M. Górska H. Grawe M. Kaspar H. Schaffner Ch. Schlegel R. Schubart H. J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2000,8(2):161-164
High-spin states in 202Pb and 203Pb have been investigated by in-beam γ-ray spectroscopy following the reaction 198Pt(9Be,xn). A search for magnetic rotational bands in these isotopes confirmed one of the two bands previously assigned to 202Pb and revealed a new band in this isotope. No evidence for magnetic rotation has been found in 203Pb.
Received: 24 July 2000 / Accepted: 28 September 2000 相似文献
4.
V.K.B. Kota U. Datta Pramanik 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):243-253
The SUBFF(3) dynamical symmetry limits of interacting boson – fermion – fermion model are identified and they are appropriate for heavy
deformed odd – odd nuclei for configurations with both the odd proton and odd neutron occupying all the natural parity orbits
in the corresponding valence shells. There are three symmetry limits and their correspondence with two quasi-particle (proton-neutron)
Nilsson configurations is established; one of the limits mixes both Nilsson nz's and Λ's and other two limits mix only Nilsson Λ's. The 191Ir (d,t) 190Ir single nucleon transfer spectroscopic strengths are well described by one of the symmetry limits that mixes only Nilsson
Λ's.
Received: 22 June 1998 相似文献
5.
G. Kemper A. Dewald I. Wiedenhöver R. Peusquens S. Kasemann K.O. Zell P. von Brentano H. Hübel S. Chmel A. Görgen D. Bazzacco R. Venturelli S. Lunardi D.R. Napoli F. Hannachi A. Lopez-Martens R. Krücken J.R. Cooper R.M. Clark M.A. Deleplanque I.Y. Lee A.O. Machiavelli F.S. Stephens 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):121-124
Lifetimes for low-lying members of the irregular ΔI = 1 band in 196Pb have been measured by means of the EUROBALL spectrometer using the coincidence recoil distance technique. The 164Dy(36S,4n)196Pb reaction at a beam energy of 168 MeV was used. The data were analyzed with the differential decay-curve method (DDCM).
A characteristic drop in the reduced transition probabilities with increasing angular momentum was observed in agreement with
predictions by the semiclassical model for the shears mechanism.
Received: 3 May 2001 / Accepted: 20 June 2001 相似文献
6.
A. Prévost N. Buforn A. Astier R. Duffait M. Meyer S. Perriès N. Redon O. Stézowski A. Bauchet I. Deloncle M.G. Porquet A. Görgen H. Hübel E. Mergel S. Neumann D. Roßbach N. Nenoff G. Schönwaßer A.N. Wilson R. Lucas F.A. Beck D. Curien G. Duchêne B.J.P. Gall N. Kintz J.P. Vivien D.M. Cullen 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):13-19
We report the identification of six new superdeformed (SD) bands in 197,198Pb observed with the EUROBALL IV spectrometer. The results are interpreted in the framework of cranked Hartree-Fock calculations
with approximate projection on the particle number by means of the Lipkin-Nogami method. A mixing between quasi-particle excitations
and an octupole vibration is suggested in the two SD isotopes. We have estimated the ordering of the neutron valence orbitals
and confirm indirectly a N = 118 SD gap.
Received: 20 December 2000 / Accepted: 24 January 2001 相似文献
7.
M. Rejmund K.H. Maier R. Broda B. Fornal M. Lach J. Wrzesiński J. Blomqvist A. Gadea J. Gerl M. Górska H. Grawe M. Kaspar H. Schaffner C. Schlegel R. Schubart H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):261-266
High spin states in nuclei around 208Pb were populated in deep inelastic collisions of 76Ge, 136Xe, and 208Pb projectiles with 208Pb targets at beam energies about 12% above the Coulomb barrier. New states in 209Pb were found by measuring γ-γ-coincidences. They are interpreted as the yrast states that originate from the coupling of
one neutron to the lowest excitations of the 208Pb core. The results are discussed in the frame of the shell model.
Received: 22 November 1997 相似文献
8.
M. Bender T. Cornelius G.A. Lalazissis J.A. Maruhn W. Nazarewicz P.-G. Reinhard 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):23-28
Recent mass measurements show a substantial weakening of the binding-energy difference δ2p(Z, N) = E(Z - 2, N) - 2E(Z, N) + E(Z + 2, N) in the neutron-deficient Pb isotopes. As δ2p is often attributed to the size of the proton magic gap, it might be speculated that reduction in δ2p is related to a weakening of the spherical Z = 82 shell. We demonstrate that the observed trend is described quantitatively by self-consistent mean-field models in terms
of deformed ground states of Hg and Po isotopes.
Received: 25 October 2001 / Accepted: 28 February 2002 相似文献
9.
T. Grahn A. Dewald O. Möller R. Julin C. W. Beausang S. Christen I. G. Darby S. Eeckhaudt P. T. Greenlees A. Görgen K. Helariutta J. Jolie H. Kettunen T. Kröll R. Krücken P. Jones S. Juutinen Y. Le Coz M. Leino A.-P. Leppänen P. Maierbeck B. Melon D. A. Meyer P. Nieminen M. Nyman R. Page J. Pakarinen P. Petkov P. Rahkila B. Saha M. Sandzelius J. Sarén C. Scholey J. Uusitalo 《The European physical journal. Special topics》2007,150(1):121-122
Lifetimes of low-lying yrast states in 186Pb and
194Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift
lifetime measurements. In addition, lifetime measurements of prolate states in 188Pb up to the 8+ state were carried out using the recoil gating method. The deformation parameters
and
for the prolate (186,188Pb) and the oblate (194Po) bands,
respectively, have been extracted from the measured lifetimes.
27.70.+q– 相似文献
10.
We show that the spin-orbit potential of the nuclear mean field destroys isoscalar superfluid correlations in self-conjugate
nuclei. Using group theory and boson mapping techniques on a Hamiltonian including single particle splittings and a SO
ST(8) pairing interaction, we give analytical expressions for the spin-orbit dependence of some N = Z properties such as the relative position of T = 0 and T = 1 states in odd-odd systems or double binding-energy differences of even-even nuclei.
Received: 12 April 2000 / Accepted: 25 May 2000 相似文献
11.
O. N. Malyshev A. V. Belozerov M. L. Chelnokov V. I. Chepigin V. A. Gorshkov A. P. Kabachenko A. G. Popeko J. Rohach R. N. Sagaidak A. V. Yeremin S. I. Mulgin S. V. Zhdanov 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):295-297
The new neutron deficient isotope 217U was produced in the bombardment of the 182W target with 40Ar ions and identified using a recoil-- correlation method. The -decay energy and the half-life of 217U were determined to be 8005 ± 20 keV and 15.6 +21.3
-5.7 ms, respectively.
Received: 18 May 2000 / Accepted: 21 June 2000 相似文献
12.
C.A. Gagliardi A. Azhari V. Burjan F. Carstoiu V. Kroha A.M. Mukhamedzhanov A. Sattarov X. Tang L. Trache R.E. Tribble 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):227-232
Peripheral transfer reactions can be used to determine asymptotic normalization coefficients (ANCs). These coefficients, which
specify the normalization of the tail of the nuclear overlap function, determine S-factors for direct capture reactions at astrophysical energies. A variety of proton transfer reactions involving both stable
and radioactive beams have been used to measure ANCs. Tests have demonstrated that ANCs determined from proton transfer reactions
can be used to calculate astrophysical direct capture rates to within 9%. The 10B(7Be, 8B)9Be and 14N(7Be, 8B)13C reactions have been used to measure the ANC appropriate for determining the 7Be(p,γ)8B rate, and the 14N(11C, 12N)13C reaction has been used to measure the ANC required to calculate the 11C(p,γ)12N rate.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
13.
M. Lach P. Bednarczyk P.T. Greenlees K. Helariutta P. Jones R. Julin S. Juutinen H. Kankaanpää H. Kettunen P. Kuusiniemi M. Leino W. Meczyński M. Muikku P. Nieminen P. Rahkila J. Styczeń J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):307-308
The 13/2+ isomeric state in the 199At nucleus has been identified at an excitation energy of 573 keV and its half-life measured to be 580(130) ns using the recoil-decay
tagging technique.
Received: 19 September 2000 / Accepted: 1 November 2000 相似文献
14.
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
15.
R. Krücken Z. Wang S.J. Asztalos J.A. Becker L.A. Bernstein R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon N. Fotiades K. Hauschild I.Y. Lee A.O. Macchiavelli G.J. Schmid F.S. Stephens K. Vetter 《The European Physical Journal A - Hadrons and Nuclei》1999,5(4):367-370
Lifetimes of states in the two strongest superdeformed (SD) bands in 193Tl were measured using the Doppler-shift attenuation method. The reaction 176Yb(23Na,6n)193Tl at a beam energy of 129 MeV was used and γ-rays were detected by the Gammasphere array. Quadrupole moments of 18.3(10)
eb and 17.4(10) eb were extracted for SD bands 1 and 2, respectively, using the fractional Doppler-shifts of the SD transitions.
The previously reported linking transitions of these SD bands to normal deformed near yrast levels could not be confirmed.
No other candidates for linking transitions could be established.
Received: 27 April 1999 相似文献
16.
A. Nowak W. Urban M. Rejmund J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley I. Ahmad L.R. Morss M. Bentaleb E. Lubkiewicz N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):111-113
Neutron-rich, N=84 nuclei from the 132Sn region, populated in spontaneous fission of 248Cm, have been studied with EUROGAM 2. Excited states and their spins and parities in the 136Te nucleus were established up to 17ħ. OXBASH code calculations support the experimental identification of maximum aligned
configurations in 136Te. Empirical shell model calculations for the Iπ= 14+ level in 136Te indicate that the adopted mass of the 134Te nucleus should be lowered by 200(80) keV.
Received: 3 August 1998 相似文献
17.
V.I. Isakov K.I. Erokhina H. Mach M. Sanchez-Vega B. Fogelberg 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):29-36
The latest experimental data on nuclei at 132Sn permit us for the first time to determine the spin-orbit splittings of neutrons and protons in identical orbits in this
neutron-rich doubly magic region and compare the case to that of 208Pb. Using the new results, which are now consistent for the two neutron-rich doubly magic regions, a theoretical analysis
defines the isotopic dependence of the mean-field spin-orbit potential and leads to a simple explicit expression for the difference
between the spin-orbit splittings of neutrons and protons. The isotopic dependence is explained in the framework of different
theoretical approaches.
Received: 13 February 2002 / Accepted: 20 February 2002 相似文献
18.
B. Fornal R. Broda W. Królas T. Pawłat J. Wrzesiński P.J. Daly P. Bhattacharyya Z.W. Grabowski C.T. Zhang D. Bazzacco S. Lunardi C. Rossi Alvarez G. de Angelis D.R. Napoli 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):355-357
Prompt and delayed γ-rays in nuclei of the 208Pb region produced in 450 MeV 76Ge +208Pb collisions have been studied at GASP. Yrast states above the α-decaying isomer in 211Po have been located including a 0.25 μs 31/2− isomer at 2135 keV and a 2 μs isomer at 4874 keV.
Received: 22 September 1997 相似文献
19.
J. Benlliure P. Armbruster M. Bernas C. Böckstiegel S. Czajkowski C. Donzaud H. Geissel A. Heinz C. Kozhuharov P. Dessagne G. Münzenberg M. Pfützner C. Stéphan K.-H. Schmidt K. Sümmerer W. Schwab L. Tassan-Got B. Voss 《The European Physical Journal A - Hadrons and Nuclei》1998,2(2):193-198
Projectile fragmentation of 238U in a lead target was investigated at a bombarding energy of 750 A MeV. Isotopic production cross sections of about 250 different projectile fragments in the element range Z= 30–53 were measured with the FRagment Separator (FRS). The magnetic selection and the kinematical analysis of the measured
isotopes allowed to disentangle fission and fragmentation residues. The mass loss of these residues indicates a violent collision
where a large amount of energy is dissipated. The position of the fragmentation corridor defined by the measured residues
was used to determine an effective proton-evaporation barrier.
Received: 3 October 1997 / Revised version: 27 February 1998 相似文献
20.
Z.G. Gan Z. Qin H.M. Fan X.G. Lei Y.B. Xu J.J. He H.Y. Liu X.L. Wu J.S. Guo X.H. Zhou S.G. Yuan G.M. Jin 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):21-25
An isotope of the element 105 with mass number 259 has been produced via the reaction 241Am(22Ne, 4n)259Db at E
lab = 118 MeV. The reaction products were transported and collected using the helium-jet technique and the rotating wheel apparatus.
The α-decays of the products and their daughter nuclides were detected by a set of Si(Au) detectors arranged ingeniously.
The Z and A of the nuclide have been unambiguously identified by the genetic relationship between the new activity and the known nuclide
255Lr established by α-recoiled milking measurement. The new nuclide 259Db has a half-life of 0.51±0.16 s and decays by alpha-particle emission of E
α = 9.47 MeV. Furthermore, the nuclide 258Db and its daughter 254Lr have also been clearly observed using the same projectile-target combination. Their half-lives and α-particle energies
determined in this work are in agreement with previous known data, thus also proving the reliability of our assignment of
259Db.
Received: 7 December 2000 / Accepted: 6 February 2001 相似文献