Proton-hole states in 115In observed in the 116Sn(d, 3He) reaction

The ¹¹⁶Sn(d, ³He)¹¹⁵In reaction has been investigated at E_d = 50 MeV. Thirteen transitions to states up to 3 MeV excitation energy were studied. The measured angular distributions were compared with DWBA calculations and transferred angular momenta and spectroscopic factors were deduced. Levels at 1.04, 2.23 and 2.52 MeV were found to be excited most likely by l = 3 angular momentum transfer in contrast to previous investigations at lower incident energies in which no l = 3 transitions have been observed.     

Study of the 58Ni(τ, α)57Ni reaction at 25 MeV

The ⁵⁸Ni(τ, α)⁵⁷Ni reaction has been studied at 25 MeV incident energy. Angular distributions have been measured from 5° to 50° with a split-pole spectrometer up to 13.5 MeV excitation energy. A local zero-range DWBA analysis has been carried out, allowing l-assignments for about eighty levels, most of them previously unknown. An isospin-dependent potential has been used in the calculation of the neutron form factor for both T_<and T_> states, and the C²S values deduced using this procedure are compared to those obtained with the usual separation energy method. Analog states of eleven ⁵⁷Co levels have been identified and the eventuality for isospin mixing in ⁵⁷Ni has been discussed. A sum rule analysis has been carried out and energy centroids of hole states have been determined. About 60% of the $\text{1}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{and}\text{2}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{T}{}_{\mathrm{<}}$ strengths and the full $\text{1}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ hole strengths are observed. It is shown that the two excess neutrons in the ⁵⁸Ni ground state mainly populate the $\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{, 1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ orbitals, whereas the occupancy number of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ subshell is found to be smaller than 0.1%. Some non-pickup angular distributions have also been observed and a CRC analysis assuming two-step processes in the (τ, α) reaction and weak-coupling wave functions for final states has been attempted. Assignments of J^π values are proposed for four ⁵⁷Ni levels, based on this analysis.     

Study of low-lying states in 92Tc with the 92Mo(3He,t) reaction

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 $\text{(1g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{\pi }}\text{(1g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{\nu }}{}^{\mathrm{?1}}$ multiplet.     

The 59Co (d, 3He)58Fe reaction and 58Fe levels in the particle-vibration coupling model

The ⁵⁹Co(d, ³He)⁵⁸Fe reaction at a deuteron energy of 33.3 MeV was used to populate proton hole states in ⁵⁸Fe. Angular distributions were measured for the states up to 6 MeV excitation. From DWBA analysis, l-values and spectroscopic factors were extracted. The particle-vibration coupling model was used to interpret the positive-parity states observed in the present experiment as well as the related properties of ⁵⁸Fe established so far. The model calculation has reproduced rather well the level properties of ⁵⁸Fe.     

The reaction 3He + p → p + p + d studied with BOL at 69 MeV 3He incoming energy

The proton-induced ³He breakup into p and d has been studied in a kinematically complete way at 69 MeV ³He-incoming (23 MeV p-incoming) lab energy, using the spherical multi-detector array BOL.The four-dimensional cross-section data cover most of the three-body final-state phase space. By slicing and integrating the data, they have been brought into suitable one- and two-dimensional representations to reveal different aspects of the reaction process. Based on these, this paper presents information on the interplay between the different reaction modes occurring in the p³He breakup process. In particular, pp final-state interaction, pp and pd quasi-free scattering and nucléon transfer have been studied here.Anomalous effects, probably due to interference between these processes, show up in the data.     

High-spin particle states in 151Sm studied with the (α, 3He) reaction

High-spin states have been located in ¹⁵¹Sm by means of the (α, ³He) reaction with 40 MeV α-particles. The scattered particles were momentum analyzed in a QMG/2 magnetic spectrometer and recorded in a position sensitive detector. Several high-spin states were observed in the energy range below 1.7 MeV excitation. The previously unknown strongly populated levels at 867 and 1480 keV can most likely be interpreted as $\text{13}\text{2}{}^{\mathrm{+}}$ states. Both the deduced nuclear structure factors and the energy location of these levels are in excellent agreement with a simple Coriolis coupling calculation.     

A study of the 59Co(n,n′γ)59Co reaction

The ⁵⁹Co(n, n'γ)⁵⁹Co reaction has been studied for incident neutron energies ranging from 1.3 to 3.9 MeV. The pulsed-beam time-of-flight technique was employed to discriminate between the inelastically scattered neutrons and the de-excitation γ-rays, which were detected by means of a true-coaxial Ge(Li) detector. Thirty-five levels were identified in this way, and their excitation functions have been extensively compared with the predictions of the statistical theory of the compound nucleus. Possible spin assignements to the levels of ⁵⁹Co are discussed and compared with the results available from previous works.     

The (3He,d) reaction on 24Mg and 28Si at 38.5 MeV

The (³He, d) reaction at a sufficiently high energy is considered to be a reliable single-proton stripping direct reaction. The data for the low-lying states produced by this reaction on ²⁴Mg and ²⁸Si are compared to the predictions of the strong-coupling rotational model. The agreement with the model predictions for ²⁵Al is quite good, both for the single-proton spectroscopic factors in that nucleus and most particularly for the excitation of $\text{7}\text{2}{}^{\mathrm{+}}$ states in ²⁵Al and ²⁹P by two-step processes.     

Study of the (3He,d) reactions on 58, 60Ni and 56Fe near the Coulomb barrier

Using spectroscopic information gained by earlier measurements of the proton bound states populated by stripping reactions, (³He, d) reactions on ^{58, 60}Ni and ⁵⁶Fe targets are studied at energies near the Coulomb barrier and evaluation is made of the vertex function . This value is then used to determine spectroscopic factors for low-lying states in ⁵⁷Co.     

High-spin states in 58Ni

High-spin states of ⁵⁸Ni were investigated via the study of in-beam γ-ray induced by the compound reaction ⁴⁸Ti(¹²C, 2n)⁵⁸Ni between 26 and 48 MeV. The energies and decay modes of these levels were determined from the analysis of γ-γ coincidence measurements at 35 MeV. The most intense lines in the ⁵⁸Ni γ-ray spectrum correspond to a cascade to the ground state, through levels at 1.454, 2.459, 3.619 and 4.381 MeV, also fed in other reactions, and by two previously unknown levels at 5.125 and 5.662 MeV; the spin assignments based on the present study are (apart from the ground state) 2, 4, 4, 5, 6 and 7 respectively for these levels. The first three were already known and the last three are new. The mixing ratios for the transitions between these levels are also determined. We observe also the same cascade in the reaction ⁵⁶Fe(α, 2n)⁵⁸Ni at an incident energy 18–24 MeV. Comparisons with other reactions, previous studies and recent shell-model calculations are presented.     

Cross sections and analyzing powers for fast-neutron scattering to the ground and first excited states of 58Ni and 60Ni

Differential cross sections for neutron scattering from ⁵⁸Ni and ⁶⁰Ni to the ground state and first excited state have been measured at 8, 10, 12 and 14 MeV. In addition, analyzing powers were measured for scattering to the same states for ⁵⁸Ni at 10 and 14 MeV, and for ⁶⁰Ni at 10 MeV. The data were analyzed in the framework of a coupled-channel formalism in which the vibrational model was assumed with deformed central and spin-orbit potentials. A spherical-optical-model analysis of the elastic scattering data was also performed following the coupled-channel analysis. Predictions for (p, p) and (p, p') scattering observables have been made and compared with measurements previously published. This approach permits neutron and proton deformation parameters to be deduced similarly from (n, n') and (p, p') scattering measurements for ^58,60Ni. These deformation parameters are compared in the framework of the core-polarization model of Madsen, Brown and Anderson.     

Energy levels of 56Co studied by the 58Ni(d, α)56Co reaction near 0°

Tensor analyzing powers, T₂₀, of outgoing α-particles in the ⁵⁸Ni($\text{d}$, α)⁵⁶Co reaction at detection angles near 0° have been measured for excited states in ⁵⁶Co for beam energies of 6.75, 7.0, 7.5, 9.0 and 9.5 MeV. Thirty-seven spin-parity combinations for ⁵⁶Co excited states have been deduced. Previous J^π ambiguities for 11 of these states have been eliminated, and results in conflict with existing assignments for the levels at 3.235 and 3.378 MeV have been obtained. A search for 0⁺ states was carried out from angular distribution measurements at forward angles of the unpolarized (d, α) reaction. The combined results from this and previous experiments were found to be in reasonable agreement with calculated level schemes.     

The 4He(p,d)3He reaction at 770 MeV

The differential cross section of the ⁴He(p, d)³He pick-up reaction has been measured at E_p = 770 MeV. The data are analysed in the framework of the DWBA; both one-nucleon and one-N¹ transfers are considered.     

A study of the 2H(3He, 4He)1H reaction with a polarised 3He beam at 27 and 33 MeV

Angular distributions of the ³He analysing power and differential cross section were measured for the ²H(³He, ⁴He)¹H reaction at incident ³He lab energies of 27 and 33 MeV. Analysis of this and other data suggest the presence of a broad resonance, or resonances, around 28 MeV excitation in ⁵Li. The evidence for the dominant M-matrix elements involving a change in channel spin (i.e. the ΔS = ?1 rule) is examined and also the question is investigated as to whether the data can be consistently explained without requiring tensor forces in the interaction.     

3He D-state effects in (d, 3He) reactions

The tensor analysing power of the ²⁷Al(d, ³He)²⁶Mg reaction has been measured at E_d = 12.4 MeV. The results are reproduced by predictions of the DWBA including D-state components in the ³He wave function. The magnitude of the tensor analysing power provides information on the asymptotic D-state to S-state ratio in the ³He wave function. The value obtained for ³He is in agreement with the corresponding value for ³H.     

Investigation of states in 30P via the 30Si(3He,t)30P reaction at 30 MeV

The ³⁰Si(³⁰He, t)³⁰P reaction has been measured for about 100 levels in ³⁰P with E_x < 8.8 MeV. Little selectivity in the population of states has been observed. For 75 levels angular distributions have been analysed using a “fingerprint method” by determining the L-value from a comparison in shape with transitions to states with known J^π. For possible mixed L-transitions a dominance of the higher L-value is observed for almost all cases. Coulomb displacement energy calculations utilizing shell-model wave functions have been used to identify T = 1 states.     

Absolute cross sections for the 6Li(p, 3He)4He reaction at energies below 1 MeV

Total cross sections and angular distributions in the ⁶Li(p,³He)⁴He reaction have been measured over the energy range E_p = 100?700 keV. The extrapolation of the cross section to the energy region which is of interest in controlled thermonuclear reactors is given. The values of the “astrophysical S-function” are deduced from the cross sections.     

M1 states in 58Ni observed by proton inelastic scattering at 65 MeV

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 $\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}\text{and}\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$ 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 $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ 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 $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ wave function.