共查询到20条相似文献,搜索用时 62 毫秒
1.
S. Cochavi S. Gilad M.A. Moinester J. Alster M. Buenerd P. Martin 《Nuclear Physics A》1974,233(1):73-80
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 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 multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the sextet to be unambiguously observed in this study, most probably the 5? or 4? member. The members of the sextet were populated weakly (less than 100 μb/sr) in this reaction. 相似文献
2.
D. Cline M.J.A. De Voigt P.B. Vold Ole Hansen O. Nathan D. Sinclair 《Nuclear Physics A》1974,233(1):91-104
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 particle-hole levels is compared to the lp = 3 strength distribution from pr stripping data. 相似文献
3.
Angular distributions of γ-rays from the 2H(d, γ)4He reaction have been measured at the deuteron energies Ed = 6.05, 8.96 and 11.67 MeV with a 12.7 cm × 15.2 cm NaI(Tl) crystal enclosed in a Cerenkov anticoincidence shield. A least-square fit of the angular distributions indicates that the differential cross section is proportional to sin2θ cos2θ and that the process proceeds through an E2 transition of the type . 相似文献
4.
Energy levels of the even-mass odd nucleus 96Tc have been populated with the 95Mo(3He, d)96Tc reaction at a bombarding energy of 33.6 MeV and with 28 keV resolution (FWHM). Thirty levels were observed below 2.10 MeV excitation. Comparison of experimental angular distributions with DWBA calculations allowed l-value assignments and the extraction of spectroscopic factors for most levels. Over eighty-five percent of the observed spectroscopic strength is located in the lowlying configuration multiplet. A simple residual interaction shell model calculation reproduces the observed low-lying positive parity multiplet relatively well although the experimental spectrum indicates much configuration mixing is present. 相似文献
5.
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
6.
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
7.
Energy and angular distributions of neutrons from the reaction 14C(d, n)15N have been measured at 6.5 MeV deuteron energy. The DWBA analysis yielded l-values and absolute spectroscopic factors for fifteen states in 15N below 10 MeV excitation energy. For the 9.23 MeV level Jπ is determined to be + or +, for the 9.93 MeV level the data suggest . The spectroscopic factors are in qualitative agreement with pure jj coupling and in semi-quantitative agreement with shell-model calculations. 相似文献
8.
The nucleus 11B has been studied over the excitation energy range from 8.5 MeV to 21.5 MeV with the 9Be(3He, p)11B / reaction at / E3He = 38 MeV. The analogs of the parent states in 11Be have been located at 12.56, 12.92, 14.40, 16.44, 17.69, 18.0, 19.15 and 21.27 MeV. A complementary measurement with the 9Be(α, d)11B reaction at Eα = 48 MeV demonstrates that the 16.44, 17.69, 18.0 and 19.15 MeV resonances have rather pure isospin . The 14.40 MeV state is a strongly isospin-mixed analog of the state in 11Be. It is argued that spin S = 1 transfer is involved in the excitation of the 16.44 MeV state and its 3.887 MeV parent in 11Be in a two-step stripping process. The states and the lowest three states are compared with the predictions of DWBA utilizing shell-model form factors. It is concluded that the strength is more strongly fragmented than is implied by the calculations of Teeters and Kurath. 相似文献
9.
S. Gilad S. Cochavi M.A. Moinester J. Alster M. Buenerd P. Martin 《Nuclear Physics A》1974,233(1):81-90
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 doublet. The 1.17 state is suggested to be a member of the 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
10.
The cross section, vector analyzing power, and proton polarization have been measured for the ln = 0 reaction 116Sn(d, p)117Sn(g.s.) at 8.22 MeV. In addition, cross section and analyzing power data have been obtained at 8.22 MeV for and for 116Sn(d, p)117Sn leading to excited states of 117Sn at 0.159, 0.317, 1.020, 1.179, 1.308 and 1.497 MeV. The cross section and analyzing power for and for leading to the 1.294 MeV state of 116Sn have also been measured at 12.91 MeV. The data for 116Sn(d, p)117Sn(g.s.) have been used to separate the contributions to the analyzing power arising from spin-dependent forces in the proton and deuteron channels. A similar analysis is presented for an transition at 11 MeV. Optical-model analyses have been performed for the elastic scattering data. The reaction data have been compared with distorted-wave calculations in order to investigate the validity of various deuteron potentials, as well as to extract spectroscopic information. 相似文献
11.
S.I. Hayakawa S.K. Mark J.K. Lee J.E. Kitching G.C. Ball W.G. Davies 《Nuclear Physics A》1973,199(3):560-570
States in 92Tc have been studied by means of the 92Mo(3He, t) reaction at 27.5 MeV. The Q-value for this reaction and the excitation energy of the isobaric ground state analogue of 92Mo were determined to be ?7.882 ± 0.030 MeV and 3.813 ± 0.030 MeV respectively. Strongly populated levels in 92Tc appear to belong to configurations arising from the multiplet. 相似文献
12.
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
13.
Differential cross sections for 87Sr(d, t)86Sr transitions to the states of 86Sr were obtained with the Pittsburgh 18 MeV deuteron beam and the Enge split-pole spectrograph. States of 86Sr up to 3.82 MeV in excitation were studied with a total resolution of 12 keV. Successful distorted-wave Born approximation (DWBA) predictions for 87Sr(d, t) 86Sr angular distributions permitted the extraction of l-values and spectroscopic strengths. The sum-rule value agrees with the observed value for the configuration. The observed strength is spread over 13 states. Contrary to an earlier interpretation, the 0+ ground state is found to contain only 65% of the strength. Similarly, the full 4+ strength is not located in a single state. The new data change the interpretation of the spectrum of 86Sr. They significantly alter the deduced low-spin matrix elements and bring them into much closer agreement with those derived from 88Y. Several new negative-parity states dominated by l = 1 orbital angular momentum transfer have also been identified. 相似文献
14.
S. Fortier J.M. Maison P. Picot S. Galès E. Hourani J.P. Schapira 《Nuclear Physics A》1981,370(2):189-204
The 40Ca(α, 3He) reaction has been studied at 36 MeV incident energy. About fifty levels have been observed up to 7.1 MeV excitation energy and angular distributions were measured from 6–60° using a split-pole spectrometer. A local zero-range DWBA analysis has been carried out, and the deduced l-assignments and spectroscopic factors are compared with those obtained from previous neutron stripping experiments. Core-excited states in 41Ca with a [3? ? f7,2], [2+ ? f7,2] and [5? ? f7,2] component previously observed in inelastic scattering experiments, are selectively excited by the (α, 3He) reaction. Their angular distributions are compared with coupled-reaction-channel calculations, assuming a pure two-step reaction mechanism. The agreement between theory and experiment may be considered as rather satisfactory for a number of levels. In particular the levels and the high-spin states with are successfully described within the framework of the weak-coupling model. 相似文献
15.
C. Gaarde J.S. Larsen A.G. Drentje M.N. Harakeh S.Y. Van Der Werf A. Müller-Arnke 《Nuclear Physics A》1980,346(3):497-509
The 54Fe(3He, t)54Co reaction has been studied at 70 MeV with an energy resolution around 70 keV (FWHM). The triton spectra are characterized by sharp peaks up to 10 MeV excitation energy superimposed on a continuum. Most of the sharp peaks have a forward-peaked angular distribution and 38 peaks or groups of peaks are found to have an angular distribution corresponding to an angular momentum transfer of 2. Model considerations lead to the conclusion that most of these states are 1+ states. A shell-model calculation with parameters that account for the Gamow-Teller strength distribution in 48Ca-48Sc divides the β-strength in 54Co in a ratio 5.7:6.8:1.3 for the T = 0, 1 and 2 states. A comparison is made with the 1+ spectrum in 54Mn (T = 2 states) and a tentative assignment of T = 2 states in 54Co is reached. The cross section has been calculated for the 0+, 1+ and 3+ states in 54Co assuming a pure () configuration finite-range DWBA is used and the conclusions are that the (3He, α, t) and (3He, d, t) processes give significant contributions to the cross sections. 相似文献
16.
A high-accuracy investigation of the level scheme of 47V has been performed using the 46Ti(p, γ)47V reaction. The γ-decay schemes of the strong (p, γ) resonances at Ep = 1546, 1549, 1565 and 1572 keV lead to 17 new energy levels in 47V with excitation energies between 2.7 and 5.1 MeV. From the (p,γ) angular distributions mixing ratios of the primary γ-transitions and Jπ values of the resonances and of many states populated in the γ-decay have been determined. The total width of the Ep = 1549, 1565 and 1572 keV resonances for γ-decay are found to be Γγ = 0.12, 0.15 and 0.03 eV, respectively. The Q-value of the 46Ti(p,γ)47V reaction is found to be 5168.6 keV. The two resonances at Ep = 1549 and 1565 keV, which have , are interpreted as fine structure components of the analogue state of the level in 47Ti while the () resonance at Ep = 1546 keV might correspond to the parent state in 47Ti. The analogue-antianalogue M1 transition strength of the split analogue state is 0.01 single-particle units and fits well into our systematics of IAS → AIAS transitions in fp-shell nuclei. 相似文献
17.
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
18.
In the 48Ca (τ,α)47Ca reaction at 25 MeV, some angular distributions are well reproduced by CCBA calculations, assumping double-step excitation of states. Unambigous Jπ assignments are extracted from the analysis. 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.
The 54Fe(τ, d)55Co reaction has been studied at 25 MeV incident energy with a split-pole spectrometer. About one hundred levels have been observed in 55Co up to 10 MeV excitation energy. Angular distributions have been measured and analyzed with DWBA and Gamow functions as form factors for unbound levels. The 54Fe(τ,dp?)54 reaction has been investigated at 24 MeV incident energy. The angular distributions of the emitted protons were measured in coincidence using method 2 of Litherland and Ferguson, with 0 detection of deuteron groups. Spins, population parameters, branching ratios and proton partial widths for the transitions to the ground and excited states of 54Fe were determined from the analysis of the angular correlation data. The results of these two experiments provide a large number ofspectroscopic properties of unbound proton states and in particular of analog states of 55Fe low-lying levels. The IAS of the ground state of 55Fe is observed to be split between two individual levels. The amplitude of neutron coupling to the first 2+ excited state of 54Fe is obtained for the and low-lying parent statfes in 55Fe. summed spectroscopic factors and the centroid energies of the proton states in 55Co are obtained. A comparison is made with previous (τ, d), (d, p) and (p, p) results. 相似文献