共查询到20条相似文献,搜索用时 15 毫秒
1.
M. Adachi T. Kohno A. Makishima S. Fukuda M. Fukuda M. Taya H. Taketani 《Nuclear Physics A》1985,442(2):361-368
The g-factors of two isomeric states at Ex = 3763 and 5170 keV in 216Ra have been measured to be 0.51 ± 0.03 and 0.63 ± 0.06, respectively, with a TDPAD method. Spin and parity assignments of 19? for the 3763 keV state and 25? or 24+ for the 5170 keV state are consistent with the measured g-factors. Proposed configurations for the 19? and 25? assignments are of the same type as those predicted by a deformed independent-particle model for 214Rn, which is an isotone of 216Ra. 相似文献
2.
D. Ward H.R. Andrews A.J. Ferguson O. Häusser N. Rud P. Skensved J. Keinonen P. Taras 《Nuclear Physics A》1981,365(1):173-188
Inverse reactions of 63, 65Cu beams on 18, 16O targets have been used to populate states of 78Kr by fusion-evaporation reactions. The excited nuclei recoiled at high velocity v/c ≈ 7 % through a polarized iron (54Fe) layer and were stopped in a copper layer. During the period in iron, 0.05–0.65 ps, the nuclei were subjected to the intense transient magnetic field (initially ~ 3500 T). The resulting precession of the high-spin nuclear states populated during this time was determined by measuring the time integral rotation angle of the discrete γ-ray transitions at low spin.The average g-factor at low spin 2 ≦ J ≦ 8 compared to that at higher spin 8 ≦ J ≦ 12 in 78Kr was found to be identical within the experimental uncertainties of ~ 15 %. This result implies that either there are no rotational alignment effects at the backbend in 78Kr or more plausibly, proton (g ≈ 1) and neutron (g ≈ 0) aligned bands are equally competitive and both populated in the reaction. It is then likely that the resulting g-factor represents an average over many populated proton and neutron aligned bands. 相似文献
3.
R.H. Spear M.T. Esat M.P. Fewell D.C. Kean T.H. Zabel A.M. Baxter S. Hinds 《Nuclear Physics A》1980,345(1):252-262
The static quadrupole moments Q2+ and B(E2; 0+ → 2+) values of the 2+ first excited states of 200Hg and 202Hg have been determined using the reorientation effect in Coulomb excitation. An annular silicon surface-barrier detector was used to detect backscattered 4He, 12C and 16O projectiles. It is found that for 200Hg, Q2+ = +1.07 ± 0.19 e · b(+0.98 ± 0.19 e · b) for destructive (constructive) interference from the 2+′ state, and B(E2; 0+ → 2+) = 0.853 ± 0.007 e2 · b2. For 202Hg, we find Q2+ = +1.01 ± 0.13 e · b (+0.87 ± 0.13 e · b) and B(E2; 0+ → 2+) = 0.605 ± 0.005 e2 · b2. The Q2+ value obtained for 200Hg is in agreement with previous work, but that for 202Hg is not. The results obtained are compared with the predictions of various nuclear models, and the mass dependence of Q2+ in the region 182 ≦ A ≦ 206 is examined. 相似文献
4.
C. Roulet G. Albouy G. Auger J.M. Lagrange M. Pautrat K.G. Rensfelt H. Richel H. Sergolle J. Vanhorenbeeck 《Nuclear Physics A》1977,285(1):156-166
The g-factor of the 12+ isomeric state in lead isotopes with A = 194, 196, 198 was measured using the time-differential perturbed angular distribution method (TDPAD). The values obtained are respectively g(194) = ?0.158(6); g(196) = ?0.157(7); g(198) = ?0.144(11). A more precise determination of the 12+ level half-life is also made. The g-factprs of these nuclear states, which are described with v(i)?2 as the main configuration, are surprisingly constant over a large mass range (between A = 206 and 194). A core polarization analysis explains this trend: the polarization induced on neutrons in i orbit decreases with the mass number A (blocking effect), but a compensation is provided by the other spin-orbit partners f-f and P-P. 相似文献
5.
A double resonance experiment is used to detect the collisional transfer of orientation from an optically oriented 198Hg (63P1) atom to the hyperfine levels of a 199Hg atom. The reaction of transfer is assumed to be 198Hg (63P1) + 199Hg (61S0) → 198Hg (61S0) + 199Hg (63P1).The theory of such a process is summarized, the experimental set-up described and the double resonance signals compared with those predicted by the theory. 相似文献
6.
The energy, multipolarity and multiplicity spectra of the continuum gamma radiation feeding high-spin isomers in 148, 149, 151, 152Dy and 147Gd have been measured at several bombarding energies. The final nuclei were selected via a delayed coincidence technique while the use of a NaI(Tl) Compton shielded crystal allowed the primary gamma-ray spectra to be generated reliably from the observed spectra.It was found that: (i) the energy of both the gamma-ray statistical cascade and the neutron cascade increases with increasing excitation energy, the latter much more rapidly than expected; (ii) the multiplicity of gamma-ray cascades, in which a statistical transition was detected, is generally lower than that of the average cascade; (iii) stretched E2 spin-correlated transitions occur above and above , indicating the onset of collectivity at these spins — in addition, a region of predominantly dipole emitting states is located below ; (iv) effective moments of inertia derived from the bump edge are 50–100% larger than those deduced from the density of stretched E2 transitions in the bump; (v) in 149,151Dy the bump edge is very sharp but no multiplicity features are observed; (vi) although the four Dy isotopes were populated at approximately the same excitation energy, they display considerable differences in their continuum properties.Probable interpretations of these observations are discussed, in particular we have suggested that several of the observed effects are consistent with the possible presence of high-K collective bands above the yrast line. 相似文献
7.
The question of bubble configurations for 36Ar and 200Hg is studied by Hartree Fock calculations using the density dependent force G-0. By imposing a constraint the solutions can be studied as a function of bubble deformation. Pairing is included in a self consistent manner via a B.C.S. calculation. Factors leading to bubble versus uniform distribution are discussed. 相似文献
8.
E.M. Szanto A.Szanto De Toledo H.V. Klapdor G. Rosner M. Schrader 《Nuclear Physics A》1983,404(1):142-166
High-spin states in 22Ne have been investigated by the reactions 11B(13C, d)22Ne and 13(11B, d)22Ne up to . Yrast states were observed at 11.02 MeV (8+) and 15.46 MeV (10+) excitation energy. A backbending in 22Ne is observed around spin 8+. The location of high-spin states I ≦ 10 is discussed in terms of the rotational band structure, Strutinsky-type calculations, and pure shell-model predictions. 相似文献
9.
R.F. Davie A.R. Poletti G.D. Dracoulis A.P. Byrne C. Fahlander 《Nuclear Physics A》1984,430(2):454-484
The properties of high-spin states in 205At have been investigated to and an excitation energy of > 4.0 MeV. The properties of the + isomer at 2340 keV have been established and those of the + isomer at 2063 keV have been further investigated. In the present study the mean lives of these isomers have been determined as 11.2±0.2μs and 98±2 ns respectively. The M2 branch of the + state at 970 keV to the + ground state has been measured. This decay is attributed to a proton single-particle transition. The trend of excitation energies of a number of proton excitations in the odd-mass nuclei from 211At to 201At has been compared to the corepolarization model and the average interaction energy has been deduced. Comments are made upon probable configurations for many of the levels. 相似文献
10.
Yu.N. Rakivnenko A.P. Klyucharev V.A. Lutsik E.A. Skakun I.A. Romaniy K.-H. Kaun W. Neubert W. Schulze F. Stary L.K. Peker E.I. Volmyanski 《Physics letters. [Part B]》1973,44(5):462-464
By making use of heavy-ion and α-particle induced reactions an isomeric state has been found in 204Bi, with a half-life of and the quantum characteristics Iπ = 16+. The four-quasiparticle configuration has been ascribed to this state. 相似文献
11.
A.R. Poletti G.D. Dracoulis S.J. Poletti A.P. Byrne A.E. Stuchbery J. Gerl 《Nuclear Physics A》1985,442(1):153-162
The following mean lives of excited states in 211Rn and 210Rn have been measured: 211Rn: 8169 + Δ' keV, (τ = 3.3(3) ns), 7400 + Δ' keV (2,1(5) ns), 6101 + Δ' (41(2) ns), 5247 + Δ keV (5(2) ns), 3244 + Δ keV (3.9(8) ns), 2651 + Δ keV (9.6(4) ns); 210Rn: 8555 + Δ keV (2.6(3) ns), 4994 + Δ keV (19(1) ns), 1665 keV (15.0(15) ns). Some theoretical implications of these measurements for the structure of 211Rn and 210Rn are discussed. 相似文献
12.
Selected cascades in the level scheme of the 194Pt nucleus have been studied by the γ-γ directional correlation method and the spins of the 924, 1513, 1623, 1672 and 1798 keV levels determined to be 3, 2, 2, 2 and 1 respectively. The multipole mixing ratios of the 301, 594, 1184 and 1295 keV γ-transitions have been determined and a number of B(E2) ratios are compared with theory. 相似文献
13.
H. Bertschat U. Leithäuser W. Leitz F. Pleiter E. Recknagel B. Spellmeyer 《Nuclear Physics A》1974,229(1):72-78
Short-lived isomeric states in 108Ag and 110Ag were populated by means of (p, n) and (d, p) reactions. The nuclear g-factors of these states were determined with the pulsed beam DPAD method to be . The results indicate a spin and parity Iπ = 2+ for 108Ag and Iπ = 3+ for 110Ag. 相似文献
14.
15.
Transient field precession measurements have been performed on the first excited Jπ = 2+ states of 28Si and 30Si with the IMPAC technique on recoil in magnetized iron. The results were analyzed with empirically adjusted Lindhard-Winther predictions. This yields g-factors of , respectively. In the present cases the influence of static hyperfine fields is negligible due to the very short mean lives for 28Si and 30Si of 0.68 and 0.35 ps, respectively. The results are compared with theoretical calculations. Previous results for 26Mg(21+) were reanalyzed with the more recent lifetime of τm = 0.72 ± 0.03 ps. The value of the g-factor becomes g = +0.82 ± 0.16. 相似文献
16.
E. Bożek B. Haas B. Ingarden-Dutkiewicz K. Królas J.C. Merdinger J. Styczeń J.P. Vivien 《Nuclear Physics A》1976,266(2):457-460
The rotation of the angular distribution pattern of the 524 keV γ-radiation from the 6+, 3200 keV state in 50Ti was measured in an external magnetic field using the 48Ca(α, 2n) reaction. The IPAD method was applied. From the experimental precession angle, the value of the g-factor, g = 1.57 ± 0.17, has been derived. 相似文献
17.
H. Prade L. Käubler U. Hagemann H.U. Jäger M. Kirchbach L. Schneider F. Stary Z. Roller V. Paar 《Nuclear Physics A》1980,333(1):33-66
High-spin states of 143Pm have been studied in the reactions 141Pr(α, 2n)143Pm and 143Nd(d, 2n)143Pm by means of in-beam spectroscopy. The level scheme, spin and parity assignments are based on results obtained from singles γ-ray spectra, conversion electron spectra, prompt and delayed γ-γ coincidences, γ-ray angular distribution and linear polarization measurements. Positive- and negative-parity states with energies up to 4580 keV and spins up to have been established including 22 new levels. For two nanosecond isomeric states the nuclear spin precession in an external magnetic field was observed providing the following g-factors: The experimental results are well understood by calculations which have been performed in the framework of the shell model (for positive-parity states of 11 valence protons above a Z = 50, N = 82 core) and of the cluster-vibration model (for 3 holes in a Z = 64, N = 82 core). In the case of positive-parity states no evidence for particle-core coupling could be found, while the negative-parity states could qualitatively be understood within the particle-core coupling picture. 相似文献
18.
H.H. Eggenhuisen L.P. Ekström G.A.P. Engelbertink H.J.M. Aarts W.G.J. Langeveld 《Nuclear Physics A》1978,299(1):175-188
Yrast states of 41K and 41Ca have been investigated with the 26Mg(18O, p2nγ)41K and 26Mg(18O, 3nγ)41Ca reactions at a beam energy of 34 MeV. Gamma-gamma coincidence, γ-ray angular distribution and linear polarization measurements were performed with a Ge(Li)-NaI(Tl) Compton suppression spectrometer and a three-crystal Ge(Li) Compton polarimeter. Unambiguous spin-parity assignments of , , , , and to the 41K levels at Ex = 1.68, 2.53, 2.76, 2.77, 4.27 and 4.98 MeV and of to the 41Ca levels at Ex = 3.20, 3.37 and 3.83 MeV, respectively, have been obtained. Excitation energies, branching ratios, multipole mixing ratios and transition strengths are reported. The main features of the 41K and 41Ca level and decay schemes are reproduced in a 2p-1h and 3p-2h shell-model calculation. 相似文献
19.
Hsi-chen Chang 《Physics letters. [Part B]》1977,69(3):272-274
The effects of nuclear field r2(Y2σ1)1υ on magnetic properties of single-particle states in odd-A nuclei (208±1Pb) are considered. The coupling constant associated with this type of field is estimated by an argument that realtes it to the coupling constant for the field (γ0σ1)1υ. The effects of including the r2(Y2σ1)1υ field on the M1 moments and transitions are estimated. 相似文献
20.
The spectrum of 28Si is investigated within the cranked Nilsson-Strutinsky model with all kinds of many-particle-many-hole excitations accounted for. Calculated excitation energies and quadropole moments are compared with experimental data. The recently observed backbend from 8+ to 10+ is suggested to be caused by the crossing of the oblate ground band with a prolate or slightly triaxial band having one proton and one neutron excited to the fp shell. 相似文献