共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
3.
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
4.
M. Fujiwara Y. Fujita I. Katayama S. Morinobu T. Yamazaki H. Ikegami S.I. Hayakawa K. Katori 《Nuclear Physics A》1983,410(1):137-146
Inelastic proton scattering at 65 MeV was used to study 1+ states in 58Ni. A new 1+ state was found at an excitation of 5.166 MeV. The angular distributions for the 1+ states at 2.903 and 5.166 MeV were well reproduced by a DWBA calculation under the assumptions of pure configurations, respectively. The angular distribution for the previously suggested 1+ state at 7.721 MeV was not well discribed by the DWBA calculation with the isoscalar wave function. The shape of the angular distribution for the 10.672 MeV, 1+ state was well reproduced by the DWBA calculation with the isovector wave function. 相似文献
5.
A distorted wave analysis of the 32S(t,p) 34S reaction reveals that the 0+ state at 5.86 MeV, the 2+ state at 7.80 MeV and the 4+ state at 8.42 MeV are the principal components of the , T = 1 multiplet. 相似文献
6.
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
7.
Energy levels in 50V up to 4.3 MeV have been studied using the 49Ti(3He, d)50V and 51V(d,t)50V reactions with 3He particles of 22 MeV and deuterons of 19.5 MeV incident energy. More than eighty levels are seen, with angular distributions taken for forty-one levels in the (3He, d) reaction and for the ten lowest levels in the (d, t) reaction. The angular distributions are compared with the distorted-wave Born approximation (DWBA) to extract the l-values of the transferred nucleons and obtain the spectroscopic strengths. In the stripping reaction, a small amount of l = 0 and l = 2 strength is seen, indicating the presence of s and d proton holes in the g.s. of 49Ti. The results are compared with a recent shell-model calculation based on an configuration, and show qualitative agreement. 相似文献
8.
The characteristics of the decay sequences are discussed for the two sharp levels of 12C1 at excitation energies of 12.7 MeV (Jf = 1+, T = 0) and 16.11 MeV (Jf = 2+, T = 1), which are observed prominently in this decay process. The transition rates for these processes and the angular correlations in the final four-particle state αααπ? are discussed quantitatively, using the intermediate coupling model for both the 12ΛB and 12C1 systems, as a function of the 12ΛB spin J. Three distinct tests are proposed, which are sensitive to the spin J for ground-state 12ΛB, and which have been used by the European K? Collaboration to deduce that J = 1 for 12ΛB. The implications of this conclusion for the ΛN and ΛNN interactions are briefly discussed. 相似文献
9.
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
10.
Neutron pick-up cross sections and vector analyzing powers have been measured for the reaction 55Mn(, t)54Mn at 17 MeV. The mixture of to transfer to the low-lying ln = 1 states has been found. Evidence of the hole nature of several strong ln = 3 states above 1 MeV has been obtained. 相似文献
11.
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
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14.
H. Sakai R.K. Bhowmik S. Brandenburg J.H. Van Dijk A.G. Drentje M.N. Harakeh Y. Iwasaki R.H. Siemssen S.Y. Van Der Werf A. Van Der Woude 《Nuclear Physics A》1985,441(4):640-675
The γ-decay of deep-hole states in 101, 105, 107Pd was studied via the (3He, αγ) reaction at E3he = 70 MeV and supplemented by data from 112, 118Sn targets to investigate the deep-hole spreading mechanism. The γ-decay pattern for the deep-hole state shows a strong dependence on the spreading width: if the deep-hole state is observed as a sharp peak, it mainly decays to the low-lying state by a spin-flip M1 transition with a large M1-E2 mixing ratio; if the deep-hole state is observed as a broad bump, it decays statistically indicating the complete spreading of the hole strength over the underlying states; if the deep-hole state is observed with a structure intermediate between a sharp peak and broad bump, its γ-decay shows both decay patterns.A sharp peak at Ex = 2.396 MeV in 101Pd which carries a large fraction of the hole strength (C2S = 2.0) was found to be a single state having a width of less than 2.5 keV.For the spin-flip M1 transition the destructive interference between the component and the coupled components of the deep-hole state was found in heavily spread states.A quasiparticle-plus-rotor (QPR) model was applied to calculate the fragmentation in the doorway stage for the neutron deep-hole state in the Pd isotopes. A reasonable agreement between the calculation and the experimental results was obtained for the strength fragmentation, for the nucleus 101Pd. However, the large M1-E2 mixing ratio experimentally observed was not reproduced. 相似文献
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16.
Differential cross sections, vector and tensor analysing powers have been measured for the 61Ni(d, p) reaction at a deuteron energy of 12.3 MeV. Most of the 30 transitions observed below 8.5 MeV excitation are dominated by a single j-value, which was determined from behaviour of the analysing power data. For a number of transitions it was possible to make unambiguous j-assignment relying on the established j-dependence of the T22 tensor analysing power. The deduced spectroscopic factors indicate that the full strength of neutron transfer to the () and orbits was found and seven transitions were located above 5.3 MeV. The separated strengths of the transitions are compared with shell-model calculations for the low-lying states of 62Ni. 相似文献
17.
Masamichi Igarashi 《Physics letters. [Part B]》1978,78(4):379-383
A full finite-range second order DWBA analysis is made for 48Ca(3He, t)48Sc at 23 MeV leading to the lowest 0+ ~ 7+ states of the [] configuration taking into account both 3Heαt and 3He dt two-step processes. The effect of the finite-range of the form factors strongly reduces the contribution of 3Heαt process and the nonorthogonality corrections drastically change the contribution of 3Hedt process. Because of these effects the contributions of both processes have about the same magnitude. 相似文献
18.
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
19.
A. Cunsolo A. Foti G. Immè G. Pappalardo G. Raciti N. Saunier 《Physics letters. [Part B]》1982,112(2):121-123
Deuteron-alpha angular correlations have been measured for the reaction and θdlab=10°. Transitions involving the 11.69 MeV (6+) and the 17.6±0.2 MeV 18O states have been analyzed. Spin and parity are confirmed for the known 11.69 MeV (6+) state and assigned to be 8+ for the 17.6 MeV level. This last is suggested to be the fifth member of the positive-parity 18O rotational band built on the 3.63 MeV (0+) level. 相似文献
20.
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