共查询到20条相似文献,搜索用时 15 毫秒
1.
The nuclear structure of 5125Mn was studied by γ-ray spectroscopy in the 54Fe(p, α)51 Mn reaction (Ep = 9.0–13.2 MeV) and the 14N+39K, 16O+40Ca and 14N+40Ca fusion-evaporation reactions (Ebeam = 36 MeV). In the 54Fe(p, αγ)51Mn reaction γ-rays were detected in coincidence with α-particles emitted near 180°; mean lifetimes and γ-ray mixing and branching ratios were deduced from Doppler shift attenuation and α-γ angular correlation measurements, respectively. Definite spin assignments are: 237 and 2416 keV, ; 1140 keV, ?; 1488 keV, ?; 1825 and 2140 keV, ?. The results for other states below 3 MeV are consistent with the existence of rotational bands (/kh2/2/OI/t~ 95 keV) built on the (+) 1817 keV and + 2276 keV hole states. The various measurements together with an earlier value for the lifetime of the first-excited state determine unambiguously the B(M1) and B(E2) values for all of the decay branches of the ?, ? and ? lowest three excited states. From the γ-singles and γ-γ coincidence observations with fusion-evaporation reactions, the yrast cascade proceeds through these three states and higher states at 2957, 3250,3680 and 4139 keV which are suggested to have , ?,? and ?, respectively. The various experimental results for the ? → (?) yrast states are in good overall agreement with shell-model calculations in the (f1 space. 相似文献
2.
Differential cross sections were measured for 50Ti(p, p) at four angles for Ep = 1.83 to 2.97 MeV, with an overall energy resolution of about 350 eV. Spins, parities and total widths were extracted for 212 levels. An energy region near Ep = 1.37 MeV was also examined in order to study the analogue of the ground state of 5Ti. Coulomb energies and spectroscopic factors were determined for the analogues of the ground and first excited states of 51Ti. The latter analogue was highly fragmented. The s-wave spacing and width distributions were analyzed and the number of missing levels estimated. The and proton strength functions were determined. 相似文献
3.
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
4.
The reaction 48Ti(t, d)49Ti leading to the ground and first excited states of 49Ti has been studied at triton energies of 2.75 and 3.0 MeV. The cross section to the ground state of 49Ti has been analysed using the DWBA with a previously determined bound-state well geometry to obtain a value for the (t, d) normalization factor of D2 = (3.29 ± 0.40) × 104 MeV2 · fm3. This value is in agreement with that obtained from a comparison of the (d, t) reaction with heavy-ion single-neutron transfer reactions. Using this value of the normalization factor the rms radius of the component in the first excited state of 49Ti is found to be 4.42 ± 0.07 fm (point neutron), corresponding to the use of a local bound-state potential well. 相似文献
5.
Elastic scattering and evaporation residues have been measured for the system 32S + 27Al at Ec.m. = 66.4, 73.2 MeV and 32S + 48Ti at Ec.m. = 96.0 MeV. Reaction cross sections have been obtained by use of the optical theorem and are found to be about 60 % larger than the fusion cross sections. 相似文献
6.
H. Dumont B. Delaunay J. Delaunay D.M. De Castro Rizzo A. Brondi P. Cuzzocrea A. Donofrio R. Moro M. Romano F. Terrasi 《Nuclear Physics A》1985,435(1):301-316
Excitation functions of the reactions 12, 13C+48Ti and 30Si+30Si were measured by in-beam γ-ray spectrometry in the energy ranges 20–60 MeV for the 12, 13C induced reactions and 55–126 MeV for the 30Si+30Si reaction. Light-particle angular distributions were measured at 46 MeV and 47.5 MeV for the 13C and 12C induced reactions. Measurements of elastic scattering angular distribution and particle-γ coincidences were carried out for the system 13C+48Ti at 46 MeV. The limitation to complete fusion detected for the system 30Si+30Si appears to be related to entrance channel effects and is well reproduced by a barrier penetration calculation using the KNS potential. The angular distribution measurements carried out for the 12C+48Ti and 13C+48Ti systems allowed to identify an incomplete fusion mechanism with emission of direct α-particles before the formation of a fully equilibrated system. 相似文献
7.
Measurements of the 50Ti(γ, n) and 50Ti(γ, n0) cross sections have been made in the energy range of the giant dipole resonance (GDR). Assuming the GDR is split into two isospin components, approximated as Lorentzians, a calculation based on statistical decay of the GDR states is consistent with the experimental results. 相似文献
8.
H.H. Eggenhuisen L.P. Ekström G.A.P. Engelbertink H.J.M. Aarts 《Nuclear Physics A》1978,305(1):245-261
High-spin states of 39K and 42Ca have been investigated with the 28Si(16O, αpγ)39K and 28Si(16O, 2pγ)42Ca reactions at a beam energy of 45 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. High-spin states of 39K at Ex = 7.14,7.78and8.03 and of 42Ca at Ex = 7.75MeV are established. Unambiguous spin-parity assignments of to the 39K levels at Ex = 5.35, 5.72, 6.48, 7.14, 7.78 and 8.03 MeV and of 6?, 7?, 8?, 9? and(8, 10)? to the 42Ca levels at Ex = 5.49, 6.15, 6.41, 6.55 and 7.37 MeV, respectively, have been obtained. Further spin-parity restrictions, lifetime limits, excitation energies, branching ratios and multipole mixing ratios are reported. Discrepancies with previous Jπ assignments are discussed in detail. 相似文献
9.
The Q-value of the 40Ca(α, γ)44Ti reaction has been measured by comparing resonance α-particle and γ-ray energies to those of the prominent resonance in the 15N(α, γ)19F reaction, for which the Q-value is known with an accuracy of 0.12 keV. The result for the 40Ca(α, γ)44Ti reaction is Q = 5127.1 ± 0.7 keV. It follows that the mass excess of 44Ti is ?37549 ± 1 keV. 相似文献
10.
M. Pautrat J.M. Lagrange J.S. Dionisio Ch. Vieu J. Vanhorenbeeck 《Nuclear Physics A》1985,443(1):172-188
The 198Pb and 197Pb isotopes are produced through the 186W(16O, 4n, 5n) reactions. Conversion-electron, γ- and X-ray spectra are measured using the compound-nucleus recoil method. Conversion coefficients and multipolarities are deduced for a large number of transitions. Together with angular distribution measurements and the results of γγt multidimensional coincidences they lead to decay schemes for the two isotopes. Microscopic calculations, performed in the two- or three-quasiparticle approximation with a surface delta interaction, fail to reproduce completely the observed properties, showing similar defects for the odd and even isotope. 相似文献
11.
Gamma-ray angular distributions, nγ angular correlations, γγ coincidences and Doppler-shift attenuations have been measured in the 42Ca(α, nγ)45Ti reaction. In addition to the known positive-parity levels forming the band members are identified in 45Ti. They are the levels at 1565 keV, 1958 keV, 2258 Reduced transition probabilities are obtained for the γ-decays of these levels as well as for those of the band members. The excitation energies and transition probabilities are well reproduced by a rotation-particle-coupling model calculation with deformation parameter β = 0.30–0.35. 相似文献
12.
Delayed γ-rays from 98Tc have been observed following pulsed proton beam bombardment of an enriched 98Mo target. The energies of the delayed γ-rays are 43.5 ± 0.5 keV and 21.8 ± 0.1 keV. Also seen are delayed Tc X-rays. These radiations all have the same half-life which has been measured to be 14.6 ± 0.7 μs. The 21.8 keV γ-ray is identified as the first excited state to ground state transition. An estimate of the internal conversion coefficients of the 21.8 and 43 keV decays suggests that both transitions are M1. 相似文献
13.
Excited levels of 55Mn were produced by the reaction 52Cr(α, p) at 10.5 and 11.1 MeV beam energy. A series of γ-ray measurements was made, all in coincidence with protons detected near 180°. A Ge(Li) γ-ray detector was used at 4 angles, and extensive angular-correlation measurements were made with an array of NaI(Tl) detectors. Excitation energies of 25 levels up to 3161 keV were determined, including a new level at 2215 keV. Only the level at 2285 keV and the state near 1290 keV were not observed in this range. From Doppler-shift attenuations, the mean lifetimes of 14 levels up to 2565 keV were deduced. Branching ratios and multipole mixing ratios were obtained for most of these levels. The following spin assignments were determined: 1530 keV, ; 1885 keV, or ; 2565 keV, . Reduced transition probabilities, B (M1) and B (E2), of many transitions were calculated from these experimental results and are compared with the available theoretical values. 相似文献
14.
A. Donofrio H. Dumont M.-G.Saint Laurent B. Delaunay F. Terrasi J. Delaunay 《Nuclear Physics A》1982,378(1):111-129
Absolute cross sections for nuclei produced in the reactions 46–50Ti + 13C at 36, 46 and 56 MeV (lab) were measured. Complete identification in mass and atomic number for the evaporation residues was obtained by means of in-beam γ-ray spectroscopy techniques. In the entire energy range, an overall satisfactory account of the observed product nuclei is given by the predictions of the fusion-evaporation model. Direct channels like inelastic scattering and n-transfer appear to be noticeable and contribute ~ 15 % to the total cross section. 相似文献
15.
G.S. Foote D. Branford D.C. Weisser N. Shikazono R.A.I. Bell F.C.P. Huang 《Nuclear Physics A》1976,263(2):349-364
Differential cross sections for the reactions were measured at 90° to the beam direction in 50 or 100 keV steps over the bombarding energy ranges 6.0–15.0 MeV, 5.5–11.1 MeV and 6.0–12.0 MeV respectively. Gamma-ray angular distributions were measured at forty bombarding energies. These show that the (α, γ0) reaction proceeds through 1? levels and to a lesser extent 2+ levels, whereas the (α, γ1) reaction most probably proceeds through 1? and 3? levels. It is deduced that 〈Γ〉/〈D〉 ≦ 1 for the 40Ar(α, γ)44Ca. reaction whereas the fine structure observed in the 48Ti(α, γ)52Cr reaction is probably due to fluctuations. From a comparison with other data it is shown that the (α, γ) reaction is most probably statistical in nature. Using Hauser-Feshbach theory it is deduced that the 36Ar(α, γ)40Ca. reaction is inhibited by isospin selection rules and an estimate is made of isospin mixing in the 40Ca giant dipole resonance. The data are considered with respect to theories of isosopin splitting of the giant dipole resonance. 相似文献
16.
Energy levels in 42Ca up to 7.8 MeV have been studied in the neutron capture reaction 41Ca(d, p)42Ca with 12 MeV bombarding energy. Ninety-four excited states have been identified and angular distributions have been measured in the interval from 5° to 110° by means of a broad-range magnetic spectrograph. The angular distributions together with DW calculations have been used to determine In values and spectroscopic factors. The strength sum agrees with shell-model expectations if the f spectroscopic factors are renormalized by , in line with other . transfer experiments on 40Ca and 41Ca. A similar renormalization of the ln = 1 spectroscopic factors brings this strength sum in accordance with the shell-model calculations. The effective () matrix elements for 42Ca are compared with the corresponding matrix elements of 42Sc and 48Sc. The differences between the three sets of matrix elements are of the order of a few hundred keV or less. The monopole centroid energy of the ( multiplet is shifted downwards in the mass-42 nuclei compared to 48Sc, possibly indicating the importance of the monopole pairing force near 40Ca. 相似文献
17.
The 42Ca(α, 3He)43Ca reaction has been studied at 36 MeV incident energy. Angular distributions have been measured from 4° to 42° using a split-pole spectrometer and position sensitive Si detectors, for about 40 levels located up to 6 MeV excitation energy. A local zero-range DWBA analysis has been carried out; l = 3 and 4 assignments are tentatively proposed for levels located above 4 MeV excitation energy, indicating a strong fragmentation of the strength between 4 and 6 MeV and the location of the main component of the strength above 6 MeV. A number of weakly excited levels cannot be reproduced by DWBA analysis. Their angular distributions have been compared with the results of coupled-reaction-channel calculations assuming two-step excitation of weak coupling states with a [42Ca1 ? structure. A reasonable agreement has been obtained, confirming that the two-step process cannot be neglected in the analysis of the (α, 3he) reaction. 相似文献
18.
Differential cross sections were measured for 42Ca(p, p) at four angles between Ep = 1.2 and 3.0 MeV, with an overall energy resolution of 325 eV. Spins, parities and proton widths were extracted for 170 resonances. Two analogue states were identified and spectroscopic factors determined. The nearest neighbor spacing distributions were analyzed. Proton strength functions were determined for +, ? and ? resonances. 相似文献
19.
The 46, 48, 50Ti(p, α) 43, 45, 47Sc reactions have been studied at a proton energy of 40.35 MeV with an overall energy resolution of about 80 keV FWHM. Angular distributions for states with excitation energies up to about 7 MeV in 43Sc and 45Sc and up to 8.4 MeV in 47Sc are presented. Both positive- and negative-parity states were observed. A microscopic form factor formalism for the three-nucleon transfer reaction was applied to extract quantitative information. Zeroth order calculations have been performed assuming the simplest possible configuration for the transferred nucleons. Subsequently, the ( shell-model wave functions of Kutschera et al. have been used in a more detailed test, considering the components with different neutron angular momentum couplings. Reasonable agreement was obtained for most of the states considered. The effect on the calculated analyzing power of including different configurations for the g.s. transition in 47Sc was found to be small. 相似文献
20.
S. Raman P.H. Stelson G.G. Slaughter J.A. Harvey T.A. Walkiewicz G.J. Lutz L.G. Multhauf K.G. Tirsell 《Nuclear Physics A》1973,206(2):343-352
We have carried out measurements on the decay of 119In isomers and the 118Sn(n, γ) reaction to supplement Coulomb excitation measurements on 119Sn. In addition to the 311.39 keV isomeric transition in 119In, we observed 13 γ-rays in 119Sn from the decay of the 2 min and 18 min 119In isomers. These γ-rays have been incorporated into a level scheme of 119Sn with levels at 0, 23.867, 89.54, 787.01, 920.5, 921.4, 1089.5, 1187.76, 1249.67, 1304.44 and 1354 keV. Conclusive evidence for the existence of a 920.5–921.4 keV, level doublet was obtained from capture γ-ray measurements of resonance energy neutrons. 相似文献