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1.
The 48K, 49K and 50K nuclides have been produced in high energy fragmentation and analyzed by mass spectroscopy techniques. Their half-lives have been measured as 6 ± 1 s, 1.1 ± 0.3 s and and 0.7 ± 0.3 s, respectively. The γ-rays from their radioactive decay have been observed and the corresponding γ-intensities measured. The nuclide 50K is shown to be a delayed neutron emitter. The antianalog states in the daughter Ca nuclei with a (1d32)? neutron configuration, preferentially populated in the β-decay, have been located. The corresponding 1d32 neutron single-particle energy is found to remain approximately constant for these neutron-rich Ca isotopes.  相似文献   

2.
The doubly odd nucleus 140Pr has been investigated by means of the 141Pr(d, t)140Pr and 140Ce(p, nγ)140Pr reactions. Twenty-eight levels, up to 1300 keV excitation, were observed in the pickup study. DWBA analysis was used to determine l-values and spectroscopic factors for all but a few which are very weakly populated. Gamma-ray angular distributions, measured at Ep = 4.78 MeV for the five strongest γ-rays, show appreciable nuclear alignment and demonstrate the feasibility of such experiments in this mass region. Taken together, the two studies have permitted the identification of the 12 levels expected from the low-lying (π2d52ν2d32?1), (π2d52ν3s12?1), (π1g72ν2d32?1) and (π1g72ν3s12?1) configurations. Tenta assignments for the strong odd-parity states are suggested on the basis of their spectroscopic factors.  相似文献   

3.
The nuclear g-factor of the 2543 keV, 7+ state 40K has been measured as g = 0.59 ± 0.10. Time-integral perturbed angular distributions were measured in an external magnetic field and, after implantation, in the hyperfine field at potassium in nickel. The experimental value is discussed within the f722andd32?2f722, configurations.  相似文献   

4.
High-spin states in 38K are investigated with the 24Mg(16O, pnγ)38K reaction at E(16O) = 36–44 MeV. A recently developed Compton-suppression spectrometer with 120 msr solid angle and a pulsed beam are employed to study their γ-decay. For the E4 transition from the isomeric level at Ex = 3458 keV to the ground state a branching ratio of (0.15 ± 0.02)% is found. On the basis of angular distribution and polarization measurements, in which the delayed feeding component is eliminated, spin-parity assignments are obtained of Jπ(2646 keV) = (2, 4)?, Jπ(3420 keV) = (4, 6)? and Jπ(3458 keV) = (5, 7)+. Prompt-delayed and prompt γγ coincidence experiments are performed to locate high-spin levels above the isomer. Hitherto unobserved levels of high spin are found at Ex = 5254, 7397, 8693, 8747 and 10980 keV and assignments of Jπ = (9+), (10?), (12?), (11?) and (13?) respectively, are suggested by weak-coupling considerations. The experimental results are compared with a large-scale shell-model calculation performed in a configuration space with a 28Si core and ten active particles distributed over the (2s12, 1d32, 1f72, 2p32) shells. The high-spin states appear to have a rather simple shell-model structure.  相似文献   

5.
The 91Zr(d, 3He) reaction was studied at a deuteron energy of 28 MeV. Angular distributions were measured from 13° to 47°; lp values were extracted for the prominent lines of 90Y. The lp values and transition strengths were determined by DWBA analysis. The angular distributions for the p12)(νd52) doublet (g.s. and 0.20 MeV state) exhibit the characteristic l = 1 shape. States at 1.42, 1.57, 1.64 and 1.81 MeV were also populated strongly in the (d, 3He) reaction; the 1.42, 1.57 and 1.81 MeV levels contain l= 1 transition strength and are most likely members of the p32?1)(νd52) multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the f32?1)(νd52) sextet to be unambiguously observed in this study, most probably the 5? or 4? member. The members of the g52)(νd92) sextet were populated weakly (less than 100 μb/sr) in this reaction.  相似文献   

6.
The 41Ca(d, t)40Ca and 41Ca(d, τ)40K reactions have been investigated at a bombarding energy of 40 MeV. A distorted-wave analysis of the measured angular distributions and a sum-rule analysis of the resulting spectroscopic factors has enabled the identification of members of various particle-hole multiplets. Values obtained for the matrix elements of the 1f72?1d32?1 effective interaction are in poor agreement with values obtained from other nuclei, but are reasonably well reproduced by calculations with a simple force.  相似文献   

7.
The proton transfer on 40K has been studied with the 40K(3He, d)41Ca reaction at 13 and 21 MeV bombarding energy and with the 40K(d, n)41Ca reaction at 6.5 MeV bombarding energy. The energy and angular distribution of outgoing particles have been measured. For transitions to 62 levels in 41Ca the l-values and spectroscopic factors have been derived with DWBA. The excitation energies of levels populated with l = 3 and the qualitative distribution of transfer strength strongly suggest their interpretation as 2p-1h states of the f722d32?1 configuration with weak coupling between the particle pair and the hole. The high-spin states of this configuration (with Jπ up to 152+) are preferentially excited.  相似文献   

8.
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 Jπ = 72+, 112+, 112?, 132+, 152? and 192? to the 41K levels at Ex = 1.68, 2.53, 2.76, 2.77, 4.27 and 4.98 MeV and of 92+, 112+and152+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   

9.
The g-factors of the 10+ isomeric states in 194Hg and 196Hg have been measured using the in beam IPAD method. The results g(194Hg) = ?0.24(4) and g(196Hg) = ?0.18(9) are in agreement with the value expected for an (i132?2) neutron satructure and clearly contradict the previous assignment as (h112?2) proton configurations. Cranking model calculations show that the neutron excitation energies in the rotating frame agree satisfactorily with the experimental energies and that the proton excitations are expected ≈2 MeV above the experimental yrast line  相似文献   

10.
The non-selective nature of the (α, nγ) reaction has been used to complement information from charged-particle reactions on the level structure of 88Y and 90Y. The γ-ray spectra were recorded with a 25 cm3 Ge(Li) detector at 90° to the beam using primarily targets of 85Rb2CO3 and 87Rb2CO3 and α-particle energies of 11.8, 12.2 and 13.0 MeV. The resulting transitions were accommodated in level schemes that involved primarily the following shell model configurations: p12)1g92)?1, g92)?1g92)1, p12)1p12)?1, f52)?1g92)?1 in 88Y and p12)1d52)1, πg(92)1d52)1,p12)1s12))1 in 90Y.  相似文献   

11.
The (d, 3He) and (α, t) proton transfer reactions on 91Zr were studied at incident energies of 24.3 and 35.4 MeV, respectively. Angular distributions were measured from 6° to 50° (90Y) and 60° (92Nb). High detection efficiency and good energy resolution were obtained by using a magnetic spectrograph in connection with a multiwire proportional chamber. For the low-lying multiplet levels in both nuclei angular momentum transfers and spectroscopic factors were determined by DWBA analysis. In 92Nb the states at 0, 0.135, 0.29, 0.36 and the sum of the states at 0.48 and 0.50 MeV show typical l = 4 shapes. They belong to the (1g92π)(2d52ν) sextet. The corresponding multiplet in 90Y is weakly populated ( ≦ 20 μb/sr), and l = 4 shapes are found for the levels at 0.68, 0.78, 0.95, 1.05 and 1.30 MeV proving previous assignments. The members of the low-lying (2p12π)(2d52ν) doublets in 90Y and 92Nb exhibit a characteristic l = 1 angular shape. The levels at 1.42, 1.57, 1.64, 1.76 and 1.81 MeV in 90Y are excited both by l = 1 and l = 3 resulting from a strong mixing of the (2p32π)?1(2d52ν) and (1f52π)?1 (2d52ν) multiplets. Only the level at 2.03 MeV displays a pure l = 3 shape. From the spectroscopic information on the (2p12π)(2d52ν) and (1g92π)(2d52ν) multiplets in 90Y and 92Nb the g.s. configuration mixing in 91Zr is deduced.  相似文献   

12.
Energy levels in 40Ca up to 10.2 MeV have been studied in the neutron pickup reaction 41Ca(τ, α)40Ca with 20 MeV bombarding energy. Thirty excited states have been identified and angular distributions have been measured in the interval from 5° to 40° by means of a split-pole magnetic spectrometer. The angular distributions together with DW calculations have been used to extract ln values and spectroscopic factors. The ln = 2 strength distribution for the f72d32?1 particle-hole levels is compared to the lp = 3 strength distribution from pr stripping data.  相似文献   

13.
Using the OSIRIS on-line isotope separator facility, the decays of 130Sn and 130, 132Sb have been studied. On the basis of singles γ and γ-γ coincidence Ge(Li) spectra and conversion electron Si(Li) measurements, level schemes for 130Sb, 130Te and 132Te have been constructed. The corresponding half-lives have been measured using multiscaling technique. The 3.8 min ground state of 130Sn populates only positive parity states in the πν?3 nucleus 130Sb: the energetically lowest 5+ state with the (π1g72, ν2d32) configuration assignment; the T12 = 3.6 ± 0.3 ns 4+ state at 70.0 keV; the 2+ state at 262.5 keV; the (0, 1)+ state at 697.2 keV; the 3+ state at 813.1 keV and the 1+ state at 1042.3 keV excitation energy. A 1.7 min isomeric state in 130Sn, with the tentative spin assignment (7?), populates several odd parity levels in 130Sb. These arise from the (π1g72, ν1h112-1) and/or (π2d52, ν1h112-1) configurations and are located 84.7 keV (6?), 144.9 keV (7?), 688.5 keV and 1044.0 keV above the 40 min 8? β- decaying state. No transitions between odd and even parity states have been observed.The most important excited states in 130Te found in the β? decay of the 6.6 min 130Sb 5+ state are: 839.4 keV, 2+; 1632.8 keV, 4+; 1815.1 keV, 6+; 2100.8 keV, 5?.Levels in the π2ν?2 nucleus 132Te were observed in the β? decays of the 2.8 min 132Sb (4+) and the 4.2 min 132Sb (8?) states. Unique spin and parity assignments have been given to the following states: 973.9 keV, 2+; 1670.7 keV, 4+; 1774.1 keV, 6+; 1924.7 keV, 7?; 2053.0 keV, 5?.  相似文献   

14.
15.
High-spin states in 195, 197Tl have been populated with (α, xn) reactions and studied by means of in-beam γ-ray and e? spectroscopic methods. Complementary studies of the decay of 195, 197Pb to 195, 197Tl have been carried out. Several new features have been observed in these nuclei. The 92? bands of 195, 197T1. extended to 272(?) and 292(?), respectively, show a quenching of energy spacings between the 232?, 252?, 272(? and 292(? states. This has been interpreted as resulting from the coupling of a h92 proton to the (πh?2112)8+, 10+ configurations in the core nuclei 194, 196Hg. Furthermore, positive-parity bands based on 152+ states were established up to the 352(+) and 292(+) states in 195, 197Tl respectively. Probably these bands originate from the coupling of a h92 proton to a broken neutron pair. This pair consists of a rotation-aligned i132 neutron and a low-j neutron in the P12, P32 or f52 shell. It is known to constitute the 5? bands in 194, 196Hg.  相似文献   

16.
The hole-hole structure of 94Y was studied via the reaction 96Zr(d, α)94Y and compared to the particle-hole structure of 90Y, which was populated by the reaction 92Zr(d, α)90Y. The deuteron beam energy was 28 MeV. Angular distributions of both reactions were obtained for the prominent lines. New states of 94Y were observed at 0.44, 1.17, 1.39, 1.53, 1.82, 1.90, 2.17, 2.33, 2.46 and 2.77 MeV. Our data are consistent with the previously reported 2? assignment of the ground state, and we suggest Jπ = 3? for the 0.44 MeV state, these being members of the (π2p12, ν2d32?1) doublet. The 1.17 state is suggested to be a member of the (πp32?1, νd52?1) multiplet. The Q-value of the 96Zr(d, α)94Y reaction was measured to be 7.609 ± 0.020 MeV. The reaction 94Zr(d, α) was performed at two angles. Several new states of 92Y were observed at 0.31, 0.78, 1.03, 1.31, 1.49, 1.69 and 1.89 MeV.  相似文献   

17.
The structure of 92Nb has been investigated using the 33.8 MeV 92Zr(3He, t) and (3He, p2nγ) reactions. Several previously unobserved levels, including several belonging to the π(g92)ν(g92)?1 multiplet, are reported. The results are discussed in terms of the shell model.  相似文献   

18.
Line strengths and self- and nitrogen-broadened half-widths were measured for spectral lines in the ν3 and ν2 + ν4 bands of 12CH4 and 13CH4 from 2870–2883 cm?1 using a tunable diode laser spectrometer. From measurements made over a temperature range from 215 to 297 K, on samples of 12CH4 broadened with N2, we deduced that the average temperature coefficients n, defined as bL0(T) = bL0(T0)(TT0)?n, of the Lorentz broadening coefficients for the ν3 and ν2 + ν4 bands of 12CH4 were 0.97 ± 0.03 and 0.89 ± 0.04, respectively. A smaller increase is observed in line half-width with increasing pressure for E-species lines, for both self- and nitrogen-broadening, than for other symmetry species lines over the range of pressures measured, 70 to 100 Torr.  相似文献   

19.
The g-factor of the [π(2p12)1v(2d52)1]2? state in92Nb(τ = 6.2 μsec) was determined by means of perturbed angular distribution methods using the 92Zr(p, n)92Nb reaction in a liquid alloy. The extracted v(d52) magnetic moment is discussed in terms of the core-polarization effect.  相似文献   

20.
A study of the level structure of 187Os has been performed by means of (d, p), (d, t) and (d, d)? reactions. Based upon the data presented and information available from the 10.5 h decay of 187Ir, a level scheme including several new states and level assignments is proposed. The low-lying rotational bands built on the 12? [510] and the 32? [512] single-particle states have been analysed by means of Coriolis-coupling calculations including attenuations of the coupling matrix elements. The calculations involve fits to energies, to neutron transfer cross sections and to ratios of B (E2) values.  相似文献   

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