The46Ti(d,τ)45Sc reaction

The⁴⁶Ti(d, τ)⁴⁵Sc reaction has been investigated at an incident energy of 52 MeV. Angular distributions have been taken for 14 τ-groups corresponding to excitation energies below 4 MeV in⁴⁵Sc. Spectroscopic factors were extracted through DWBA calculations. Spins and parities of 5/2⁺ are proposed for states at 1.30, 1.80, 2.91, 3.48, and 3.72 MeV. The hole state spectrum of⁴⁵Sc closely resembles that of⁴⁷Sc. A strong fractionation of the 1d _3/2 strength was not observed in contrast to other recent work. The data provide evidence for (1f _7/2 · 1f _5/2 ¹) components in the ground state wave function of⁴⁶Ti, which demonstrates that such configurations are not restricted to neutron excitations.     

Energy distribution of the <Emphasis Type="Italic">E</Emphasis>1-transition strengths in the <Superscript>46</Superscript>Ti nucleus

The structure of levels of the ⁴⁶Ti nucleus is studied by means of the nonselective reaction ⁴⁵Sc(p, γ) at proton energies ranging between 1.2 and 3.1 MeV. Spin-parity assignments for ⁴⁶Ti states of excitation energies up to 5.5 MeV are obtained by using the method of averaged resonances. Radiative strength functions for E1 transitions populating these states are determined. The resulting data are compared with predictions of various models.     

Gammaübergänge und Energieniveaus im49V aus der Reaktion48Ti(p, γ)49V

Deexcitation gamma rays of⁴⁹V from the⁴⁸Ti (p, γ)⁴⁹V reaction have been investigated at the resonancesE _p=1007, 1209, 1362 and 1374 keV corresponding to excited states in⁴⁹V at 7742, 7940, 8090, 8102 keV. A 4 cm²× 0.35 cm lithium-drifted germanium detector was used. The target was TiO₂ enriched in⁴⁸Ti to 99.4%. 71 gamma transitions have been observed. A level scheme of⁴⁹V is proposed involving 8 new levels in the energy range from 0 to 5.2 MeV excitation energy.     

Gross structure in excitation functions for207Pb(p,p′)207Pb in the region of overlapping isobaric analogue resonances

Prominent resonances in the reaction²⁰⁷Pb(p, p′)²⁰⁷Pb leading to the low-lying states in²⁰⁷Pb(1/2^? g.s., 5/2^? 0.57 MeV, 3/2^? 0.89 MeV, 7/2^? 2.33 MeV) are observed betweenE _p =16 and 18 MeV. The structures in the excitation functions are interpreted as being due to analogues of states in²⁰⁸Pb which are mixtures of neutron particle-hole configurations.     

Hermitian operator method calculation in thepf-shell

Excitations inpf-shell nuclei that may be described by a one-body Hermitian operator are calculated. For the ground states highly correlated wave functions are used, which were obtained by means of the Generator Coordinate Method (GCM). It is found that the results of the Hermitian Operator Method (HOM) for the excited states are sometimes superior to those of the GCM, especially for the two-quasiparticle states in the N=28 nuclei⁵⁰Ti,⁵²Cr,⁵⁴Fe. Typically vibrational or quasi-rotational 4⁺ and 6⁺ states in^{46, 48}Ti,⁵⁰Cr are not well reproduced by the HOM, as expected. A good account for theB(E2) values of transitions to the ground state can be given for all nuclei. It is concluded that the HOM is quite useful as a supplementary calculation and as a check for complicated calculations like the GCM.     

High-spin states in48Ti

The⁴⁵Sc(α, p γ) reaction has been investigated atE ^α=11, 12 and 13MeV. Theγ-decay of 198 levels in⁴⁸Ti up to 8,323 keV excitation energy has been observed. High-spin states were investigated by proton-γ ray angular correlation measurements atE=11 and 13MeV and by DSAM lifetime measurements atE=11 MeV. From the combined evidence spin (-parity) assignments were obtained for the levels atE _x =8,323 keV (J= 10,8,6), 8,091(12, 10, 8, 6), 7,668(10, 8), 7,427(9, 7), 7,374(11, 9, 7), 6,906(10, 8, 6), 6,172(8⁺,6⁺), 6,102(10⁺,8⁺), 6,039(6), 6,034(9⁺, 7⁺), 5,630(7), 5,197(8⁺), 5,169(7⁺), 5,155(5), 4,404(5), 4,398(6⁺) and 4,046keV (5). Most of the ambiguous spin assignments become unique if the 8,091 keV level hasJ=12, an assumption which is favoured by its excitation function. The level spectrum thus obtained is well reproduced by shell model calculations in the pure (f _7/2)⁸ configuration space. Discrepancies exist in the reproduction ofγ-decay modes. The reason is found in low-lying high-spin intruder states which include the 7,427 and 8,323 keV levels. The spectrum of negative-parity states is understood qualitatively by a comparison with⁴⁶Ti and⁴²Ca.     

Measurement of the stopping power for μ− and μ+ at energies between 3 keV and 100 keV

Spin polarization of⁴³Ti produced through the projectile fragmentation process in⁴⁶Ti on C collisions at 116 MeV/nucleon has been observed as a function of fragment momentum by means of beta-decay asymmetry. From the momentum dependence of the fragment polarization, it was concluded that negative angle deflection of the⁴³Ti fragment due to the nuclear attractive potential is the main reaction path in the case of light targets.     

Observation of deuteron D-state and compound nucleus effects in (d,p) reactions on 46Ti and 52Cr with a polarized deuteron beam

The cross section and the vector and tensor analyzing powers have been measured for ⁴⁶Ti(d, p)⁴⁷Ti at deuteron energies of 6 and 10 MeV and ⁵²Cr(d, p)⁵³Cr at 6 MeV. Transitions were observed to the states at E_x=0.159, 1.549 and 1.793 MeV in ⁴⁷Ti and the states at E_x=0.0, 0.564, 1.006 and 2.321 MeV in ⁵³Cr. In addition, the cross sections and vector analyzing powers for deuteron elastic scattering were measured for the same targets and deuteron energies and compared to optical model calculations. The choice of optical parameters for the DWBA analysis of the (d, p) reactions is discussed. Calculations made with the DWBA method show that the deuteron D-state must be included to reproduce even qualitatively the (d, p) tensor analyzing power measurements. The j-dependence of the tensor analyzing power T₂₂ is discussed. The validity of the local energy approximation (which was used to incorporate the deuteron D-state into the DWBA calculations) is evaluated by comparison to finite range calculations. The contribution of compound nucleus reactions to the measured cross sections and analyzing powers was investigated. In order to determine the compound cross section, the Ericson fluctuations in excitation functions of cross section and vector analyzing power were measured from 5 to 7 MeV on each target. The formulas used to calculate the polarization observables from the Hauser-Feshbach theory are presented.     

Investigation of high spin states in23Na and23Mg and the12C+12C resonance atE c.m.=19.3 MeV

The resonance in the¹²C+¹²C system atE _c.m.=19.3 MeV has been studied in the neutron and proton decay channels. From(p, γ), (n, p) and (n, γ) coincidence measurements high spin states could be localized inA=23 nuclei, in²³Mg up to possibly 21/2⁺. These states were resonantly populated. The present data favorJ ^π=17/2⁺ for the 9.61 MeV state in²³Mg and therefore also for the probable parent state at 9.81 MeV in²³Na. AJ ^π=12⁺ assignment to the resonance is supported and evidence was found that the resonant excitation of the lowest 15/2⁺ and 17/2⁺ states in mass 23 nuclei is caused by a change of the intrinsic structure of the Yrast levels aroundJ ^π=15/2⁺ towards larger deformation.     

Neutron polarizations from the9Be(d,n)10B and11B(d,n)12C reactions

Neutron polarization angular distributions were measured for the⁹Be(d,n)¹⁰B and¹¹B(d,n)¹²C reactions for deuteron energies of 5.47 and 5.34 MeV, respectively. Using neutron time-of-flight techniques, polarizations to eight states in¹⁰B and to six states in¹²C have been measured. Neutron polarization energy excitation functions for both reactions were measured for deuteron energies from 3.0 to 5.5 MeV in 0.25 MeV steps at 30° (lab). Distorted wave method calculations carried out to compare theoretical calculations against experimental results were not in good agreement with the data.     

Alpha-particle unstable states in12C

Alpha particle unstable states in¹²C have been investigated using the three reactions¹⁴N(d, α′)¹²C,¹⁴N(d, α′α)⁸Be and¹²C(α, α′)¹²C. Excitation cross sections and angular distributions have been measured for the reactions¹⁴N(d, α′) at 52 MeV and¹²C(α, α′) at 90 MeV. For a few angle pairs the α-decay of excited states in¹²C have been observed in a¹⁴N(d, α′α) correlation measurement. The reactions selectively excite onlyT=0 states. A previously undetected level with a large α-decay width (Γ=1.2 MeV) has been observed at 15.62 MeV excitation. This level shows up clearly in both reactions and is further distinguished from the nearby 14.08 state in the correlation measurement because of the distinctly different energy distributions of the decay products. On the basis of a particle angular distributions the 15.62 MeV level was assigned spin and parity 4⁺ and the level at 14.08 was assigned 3^?. The latter differs from the value suggest by earlier work. Comparison with DWBA calculations indicates that angular distributions of all other prominent levels are in agreement with their earlier assignments. Two levels at 19.20 and 20.30 MeV (both Γ?0.4 MeV) and three further levels at 21.81, 22.7 and 24.24 MeV also decay predominantly by α-emission.     

Spin and orbital contributions to collective M1 transitions in 46,48Ti

Low- and high-lying K^π = 1⁺ states and M1 transitions in ^46,48Ti are studied. The model hamiltonian is treated in the quasi-particle particle random phase approximation (QRPA) with an exact restoration of its rotational invariance. A considerable spin contribution to the transition matrix elements is found for the low-energy (about 4 MeV) strong M1 transition (the orbital contribution being 30–70% of the spin one), although the microscopic structure of this state in ⁴⁶Ti is typical for an orbital isovector excitation. The calculated energies and B(M1) values are in good agreement with the experimental data. The results are compared to the estimates of the isovector scissor model.     

Core-excited α-cluster structure in44Ti

With the use of a schematic⁴⁰Ca^*+α model, the low-lying positiveK=O2+ and 2⁺ bands in⁴⁴Ti, which start from the band-head energyE _x =1.90 MeV and 2.88 MeV, respectively, are shown to be well interpreted by an α-cluster structure with an excited⁴⁰Ca core, i.e.,³⁶Ar+α+α structure.     

Spectroscopy of highly excited states in29Si

Particleγ-ray coincidences have been measured in the²⁸Si (d,pγ) reaction at 6.5 and 7 MeV bombarding energy, in the²⁶Mg (α,nγ) reaction at 12, 14 and 15 MeV, and in the²⁷A1 (τ,pγ) reaction at 9 MeV. Theγ-decay has been observed for all bound states of²⁹Si and for 56 unbound states up to 12,960 KeV excitation energy. Particleγ-ray angular correlations were measured in the²⁸Si (d,pγ) reaction at 6.5 MeV and in the²⁶Mg (α,nγ) reaction at 12 MeV. Spin (-parity) assignments or restrictions were obtained for nearly all bound states and some high-spin states above the binding energy. The assignment of mirror levels in²⁹Si and²⁹P has been extended to 8.2 MeV excitation energy. The excitation energies of 41 positive-parity states are reproduced by shell model calculations. The possible existence of aK ^π=5/2⁺ band with prolate deformation is discussed.     

Spins and parities of hole states in25Na and25Mg

Angular distributions of differential cross sections and vector analyzing powers were measured forl=0, 1 and 2 transitions induced by the \(^{26} Mg\left( {\overrightarrow d ,\tau } \right)^{25} Na\) reaction at 52 MeV. The following spins and parities of final states in²⁵Na were deduced:J ^π =1/2⁺ (1.069 MeV), 3/2⁺ (2.202 MeV), 5/2⁺ (2.914 MeV), 1/2^? (3.995 MeV) and 3/2^? (5.190, 5.690, 6.549 and 7.603 MeV). The DWBA analysis of proton and neutron pick-up spectra obtained from a parallel measurement of the²⁶Mg(d, τ)²⁵Na and²⁶Mg(d, t)²⁵Mg reactions allows the identification ofT=3/2 analog states in²⁵Mg. Interpretation in terms of the Nilsson model of energies and spectroscopic factors of the first 1/2^? and 3/2^? hole states observed in proton pick-up reactions from even 1d _5/2- shell nuclei indicates a close correspondence of the final state deformations with those of the first excited 2⁺ states in the target nuclei.     

Magnetic moment measurements in64Zn and66Zn

The ratios of the ∥g∥-factors of the 7^?, 4.635 MeV level in⁶⁴Zn and 6^?, 4.074 MeV and 7^?, 4.250 MeV levels in⁶⁶Zn has been found to be (1±0.18)∶(0.64±0.14)∶(0.60±0.12) by means of the recoil-into-gas (helium) integral perturbed angular correlation technique. The studied states were populated by the reactions⁵¹V(¹⁶O,p2n)⁶⁴Zn atE ₀=51 MeV and⁵⁵Mn(¹⁴ N,2pn)⁶⁶Zn atE _N =54 MeV.     

Structure of excited states in100Mo and102Mo from spectroscopy using18O induced reactions

The lifetimes have been determined for the 2⁺, 0^+～ and 4⁺ states in¹⁰⁰Mo and¹⁰²Mo using the recoil-distance Doppler-shift method. The states have been excited in¹⁰⁰Mo by Coulomb excitation and in¹⁰²Mo by the two-neutron transfer reaction induced by¹⁸O ions on a¹⁰⁰Mo target. The study of the excitation function for the elastic and inelastic scattering on the ground and first excited 2⁺ state in¹⁰⁰Mo at beam energies between 20 and 61 MeV shows that 40 MeV is the highest incident energy for pure Coulomb excitation. Above this energy nuclear absorption sets in and nuclear scattering contributes to the excitation of the 2⁺ state of¹⁰⁰Mo. From the lifetimes of the 2⁺ and 4⁺ states deformation parameters of ¦β¦= 0.21 and ¦β¦=0.31 for¹⁰⁰Mo and¹⁰²Mo respectively were deduced. The 0^+′ levels are not shape isomeric states, as suggested earlier, but they decay by enhancedE2 transitions to the first 2⁺ states. From a comparison with similar states in other transitional nuclei it is suggested that they are band heads forβ vibrational bands.     

Coulomb interaction forJ=3/2− levels in9Be and9B

The Coulomb interaction is used to calculate energy shifts and mixing amplitudes ofJ=3/2^?,T=1/2 and 3/2 states in⁹B and⁹Be. For the 14.39 MeV level in⁹Be, a neutron width of 0.15 keV is calculated from theT=1/2 admixtures in the wave function.     

Level structure of 47Ti from the (d,p) reaction in 46Ti

The reaction ⁴⁶Ti(d, p) is studied at 10 MeV using the Aldermaston tandem Van de Graaff accelerator and a multichannel magnetic spectrograph. A total of 180 levels are observed up to an excitation of ≈ 7.2 MeV and the stripping angular distributions are analysed in terms of the DWBA theory of direct reactions using the NL/FR optical model potential. Spins, parities and spectroscopic factors are deduced for various levels. Summed spectroscopic factors and quasiparticle energies are obtained for shell model states. Properties of low-lying levels in ⁴⁷Ti are compared with the MBZ and Coriolis coupling models and also with those of the isotonic nuclei ⁴⁵Ca and ⁴⁶Sc.     

High spin states in153Er

High spin states in¹⁵³Er have been populated in the¹⁴⁴Sm(¹²C, 3n)¹³³Er reaction. Excitation functions, lifetimes, angular distributions,γ-γ coincidences and internal conversion coefficients were measured. Three isomeric states at 2.75 MeV (T _1/2=400 ns), 2.95 MeV (T _1/2～10 ns) and 5.2 MeV (T _1/2=200 ns) have been observed. A fourth isomer seems to be weakly excited above 6.8 MeV. The level scheme proposed is discussed in term of the nuclear shell model.