J.R. Lien

The 128Te(d, p) 129Te reaction at 7.5 MeV bombarding energy

Abstract The reaction 128 Te(d, p) 129 Te has been studied at 7.5 MeV bombarding energy by using the MIT broad-range, multiple-gap magnetic spectrograph. A total of 87 levels of 129 Te has been identified below an excitation energy of 4.7 MeV. The angular distributions of the protons were analysed in terms of zero-range, distorted-wave Born approximation calculations, and the orbital angular momentum of the transferred neutron was determined for 27 levels. Transition strengths were extracted and compared with pairing theory predictions. The ground-state wave function of 128 Te was found to be more complicated than expected from the simple shell model.

Nuclear reaction studies in the nickel isotopes: The 62Ni(d, p)63Ni and 64Ni(d, p)65Ni reactions

Abstract The reactions 62 Ni(d, p) 63 Ni and 64 Ni(d, p) 65 Ni have been studied at a bombarding energy of 7.5 MeV. With an energy resolution of approximately 13 keV, 78 levels in 63 Ni and 57 levels in 65 Ni were observed below 5.2 MeV and 4.7 MeV respectively. The angular distributions of the proton groups were measured for the majority of the levels and analyzed in terms of zero-range distorted-wave Born approximation calculations. Thus, information about the orbital angular momentum of the transferred neutrons and the spectroscopic strengths of the stripping levels were obtained. A sum-rule analysis was made for the 2 p 3 2 , 1 f 5 2 , 2p 1 2 and 1 g 9 2 single-particle states and the results compared with both shell-model predictions and recent pairing theory calculations. Levels whose angular distributions do not resemble any theoretical stripping curves are also discussed briefly, and some systematic trends in the level scheme of the odd Ni isotopes are mentioned.

Studies of single neutron holes in the transitional nuclei N = 83–89:: The 150, 148Nd(d, t) and 150, 148, 146Nd(3He, α) pick-up reactions

Abstract The level structures of the 145, 147, 149 Nd nuclei up to about 5 MeV excitation energy have been investigated with the ( 3 He, α) reaction at 24 MeV. Additional 17 MeV (d, t) data have been obtained for 147, 149 Nd. The angular distributions have been analyzed with standard DWBA calculations, and spectroscopic factors have been deduced. Two groups of states carrying h 11 2 single-particle strength may be associated with the 9 2 − [514] and 11 2 − [505] Nilsson orbitals. A considerable amount of high- l single-particle strength may be found in the continuum observed in the ( 3 He, α) spectra above 3 MeV in all the nuclei.

A study of the 32S levels and the analogue levels of 32P by the 31P(3He, d)32S reaction

The 31P(3He, d)32S reaction has been studied with high resolution at 12 MeV bombarding energy. A detailed level scheme for 32S has been determined up to an excitation energy of 9.5 MeV revealing several previously unobserved states. The lp values and absolute spectroscopic factors extracted from a DWBA analysis of the experimental deuteron angular distributions have provided information on the wave functions for the T = 0 states as well as for the T = 1 isobaric analogue states of 32P. A comparison between the present data and those of previous experiments is made, and the results are discussed in terms of existing theoretical work in this mass region. Information on Coulomb displacement and symmetry energies is also extracted.

Energy-level structure of 131Te from the 130Te(d, p)131Te reaction

Abstract The 130 Te(d, p) 131 Te reaction induced by 7.5 MeV deuterons has been studied using the MIT broad-range multiple-gap spectrograph. More than 100 levels of 131 Te have been identified up to 5.8 MeV excitation energy. Angular distributions have been analysed using DWBA calculations. The number of holes in the neutron shell observed were 1.0 in 2 d 3 2 , 2.0 in 1 h 11 2 , 0.32 in 3 s 1 2 , and 0.12 in 2 d 5 2 , respectively. These results are in fairly good agreement with pairing theory predictions.

Studies of single-neutron holes in the transitional nuclei N = 83–89: The 142Ce(d, t)141Ce and 142Ce(3He, α)141Ce pick-up reactions

Abstract The level structure of 141 Ce up to 3.7 MeV excitation energy has been investigated by the (d, t) and ( 3 He, α) reactions using 17 MeV deuteron and 24 MeV 3 He beams respectively. The angular distributions have been analyzed with standard DWBA calculations and spectroscopic factors are deduced. The experimental information is compared to unified model calculations involving both one-particle and two-particle one-hole configurations with quadrupole and octupole vibrations of the underlying N = 82 and N = 84 core.

The 153Sm nucleus: An experimental and theoretical study

Abstract The level structure of 153Sm has been studied by means of the 150Nd(α, n)153Sm reaction. The experiment included measurements of the γ-γ coincidences and γ-ray yield as a function of projectile energy. The rotational band built on the 11 2 − [505] Nilsson orbital was observed up to spin 19 2 , and two ΔI = 2 bands of positive parity were identified with spins up to 19 2 and 21 2 , respectively. These bands are associated with the i 13 2 single-particle structure. The data obtained in the present work together with data available in the literature are compared to the result of a particle-rotor coupling calculation. The 153Sm nucleus is found to be a wellbehaved rotor. An appropriate single-particle level scheme for 153Sm is established.

A study of the 35Cl levels by means of the 34S(3He, d)35Cl reaction

Abstract The 34S(34He, d)35Cl reaction has been studied with high resolution at 11 MeV bombarding energy. A detailed level scheme for 35Cl has been determined up to an excitation energy of 5.8 MeV revealing several previously unobserved states. The lp values and absolute spectroscopic factors extracted from a DWBA analysis of the experimental deuteron angular distributions have provided information on the single proton character of the wave functions for the T = 1 2 states as well as for the lowest T = 3 3 isobaric analogue of the 35S ground state. A comparison between the present data and those of previous experiments is made and the results are discussed in terms of the existing shell-model and unified model calculations of this nucleus. Information on Coulomb displacement and symmetry energies is also extracted.

Nuclear structure studies in the tellurium isotopes: the 126Te(d, p)127Te reaction

Abstract The reaction 124Te(d, p)125Te has been studied at a bombarding energy of 7.5 MeV in order to get information about the 125Te nuclear level scheme. The protons were recorded simultaneously at 23 angles in a multiple-gap magnetic spectrograph. One hundred and fifty two levels were observed below an excitation energy of 6.2 MeV, and the proton angular distribution for 55 of these transitions were compared to DWBA calculations in order to determine the transferred orbital angular momentum, ln, and to measure spectroscopic factors. The lower part of the level scheme was compared to the results from studies of 125Sb decay, and to theoretical pairing-theory calculations. A sum-rule analysis of the holes in the 50–82 neutron shell gave 7.95 vacancies while the expected value is 10. Single-quasiparticle energies for 125Te, 127Te, 129Te and 131Te are listed. A comparison is made with the isobaric analogue states in 125I observed elsewhere in the 124Te(p, p) reaction.

Studies of single-neutron holes in the transitional nuclei N = 83–89: The 148, 150, 152Sm(3He, α) pick-up reactions

Abstract The level structures of the 147, 149, 151 Sm nuclei up to about 5 MeV excitation energy have been investigated by means of the ( 3 He, α) reaction with a 24 MeV 3 He beam. The angular distributions have been analyzed with standard DWBA calculations and spectroscopic factors have been deduced. Two groups of states carrying h 11 2 single-particle strength are associated with the 11 2 − (505) and 9 2 − (514) Nilsson orbitals. A considerable high- l single-particle strength is found in the continuum spectra observed above 3 MeV excitation in all the nuclei.