The excited states of 27Al

The γ-decay of 60 and the strengths of 51 ²⁶Mg(p, γ)²⁷Al resonances were studied for E_p < 2.20 MeV. The energies of 32 and the γ-decay of 54 bound levels were determined. Spin and parity assignments $\text{J}{}^{\mathrm{\pi }}\text{=}\text{5}\text{2}{}^{\mathrm{+}}\text{,}\text{5}\text{2}{}^{\mathrm{?}}\text{,}\text{3}\text{2}{}^{\mathrm{?}}\text{,}\text{3}\text{2}{}^{\mathrm{+}}\text{,}\text{3}\text{2}{}^{\mathrm{+}}\text{and}\text{3}\text{2}{}^{\mathrm{+}}$ were made to the bound states at E_x = 4.81, 5.44, 6.61, 6.78, 7.68 and 7.86 MeV, respectively. Spin assignments $\text{J =}\text{5}\text{2}$and $\text{3}\text{2}$ were made to the bound levels at Einx = 5.55 and 6.08 MeV, respectively. For other levels spin and parity limitations were set. Lifetimes or lifetime upper limits of 19 bound levels were measured by means of the DSA technique. The spins and/or parities of 15 resonances were unambiguously determined from γ-ray angular distributions and strengths.     

Lifetimes and branching ratios of excited states of 24Na

The decay of ²⁴Na levels below 4.3 MeV excitation was studied by means of the ²³Na(d, pγ)²⁴Na reaction at E_d = 2.45 MeV. Gamma-ray spectra were measured at three angles, in coincidence with proton groups detected around 180°. Excitation energies, branching ratios and Doppler shifts were determined. Mean lives were obtained for the levels at 1341 keV (62±15 fs), and 1846 keV (200±50 fs). The 1347 keV level has τ >3 ps. For other levels above 1 MeV upper limits of ≈ 60 fs are set. In some cases spin restrictions follow. In particular J = 2 is assigned to the 1341 keV level.     

The 116Sn(d,t)115Sn reaction at 23 MeV

The levels of ¹¹⁵Sn up to 4 MeV excitation energy have been studied with 15–18 keV energy resolution, and many previously unreported levels have been observed. Angular momentum transfers and spectroscopic factors have been determined for most of the levels up to 3 MeV. The main features of the observed fragmentation of the strength are rather well reproduced by means of a weak coupling calculation.     

High-spin states in 155Ho

High-spin states in ¹⁵⁵Ho have been populated in the ¹⁴⁵Nd(¹⁴N, 4n)¹⁵⁵Ho reaction. Excitation functions, lifetimes, angular distributions and γ-γ coincidences were measured. An $\text{11}\text{2}{}^{\mathrm{?}}$ isomeric state with $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 0.88}\text{ms}$ has been found at very low energy. The rotational band built on this state is developed up to spin $\text{35}\text{2}$. The behaviour of its moment of inertia is compared with that of the doubly even neighbouring nuclei.     

Low-lying 134Cs excited states from the (n, γ) reaction

Low-energy γ-ray and conversion electron spectra from the ¹³³Cs(n,γ)¹³⁴Cs reaction have been investigated with a bent cyrstal spectrometer, β-speetrometer, Ge(Li) and Si(Li) detectors. Gamma-gamma coincidence measurements were made with the Ge(Li)-Ge(Li) arrangement. Gamma-gamma delayed coincidences have been studied with the use of the Ge(Li)-NaI(Tl) coincidence set-up. The decay of 2.9 h ^134mCs has been investigated with the prism β-spectrometer and Ge(Li) detector. The half-lives of the 176.403 and 257.112 keV levels have been measured to be 49.7 ± 0.8ns and 12.3 ± 1.1 ns respectively. The neutron binding energy B_n have been calculated to be 6891.4 ± 1.3 keV. Spin and parity assignments have been made for almost all the levels. The possible structure of the levels deduced is discussed.     

The g-factors of the first excited states in 78Br and 80Br

Low-lying states of the doubly odd Br isotopes were populated by means of the nuclear reactions ^{78, 80, 82}Se(p, n)^{78, 80, 82}Br. The g-factors of the first excited 2^? states in ⁷⁸Br and ⁸⁰Br were measured with the pulsed beam DPAD method and were found to be $\text{g(}{}^{78}\text{Br}\text{) = ? 0.56 ± 0.02}$ and $\text{g(}{}^{80}\text{Br}\text{) = ? 0.83 ± 0.06}$.     

Photodisintegration of 28Si to excited residual states

Integrated cross sections up to 28 MeV have been measured to excited residual states in ²¹Si, ²⁷Al and ²⁴Mg, following the photodisintegration of ²⁸Si. From comparisons with spectroscopic factors of nucleon pickup reactions on ²⁸Si, leading to the same residual states, it is concluded that the photonucleon emission process is predominantly single particle in nature. Estimates of isospin mixing in the ²⁸Si giant dipole resonance are also given.     

Spin-parity assignments of excited states in 12C

The reaction ¹²C(α, α')¹²C¹(3α) is observed by using 90 MeV a-particles in ionographic matter. The energies of the three α-particles from the break-up of ¹²C¹ are plotted in Dalitz diagrams. The density distributions for the three α-particles in the diagrams are calculated by assuming the spins and parities for the states in ¹²C¹(3α). The spin-parities for the states are assigned by comparing the observed density distributions with those calculated.     

New highly excited 4He levels found by the 2H(d,p)3H reaction

The differential cross section, the vector- and the tensor-analyzing powers of the reaction ²H($\text{d}$, p)³H have been measured. The polarization data were obtained at 11 energies between 1.0 and 13 MeV at lab angles between 5° and 160°. The data were fitted with Legendre polynomials and the resulting coefficients analyzed for resonances in ⁴He. Overwhelming evidence for a 1^? level at 24.1 MeV and a strong indication of a 4⁺ level at 24.6 MeV excitation energy have been found.     

Lifetimes of low-lying states in 19F

Lifetimes of low-lying states in ¹⁹F were measured using the Doppler-shift attenuation method through the ¹⁵N(α, γ)¹⁹F reaction. Values of τ_m = 3700 ± 700 fs (1.35 MeV), 140 ± 15 (1.46), 19 ± 7 (4.00) and 63 ± 19 (4.03) were obtained for the lowest $\text{5}\text{2}{}^{\mathrm{?}}$, $\text{3}\text{2}{}^{\mathrm{?}}$, $\text{7}\text{2}{}^{\mathrm{?}}$ and $\text{9}\text{2}{}^{\mathrm{?}}$ members, respectively, of the $\text{K}{}^{\mathrm{\pi }}\text{=}\text{1}\text{2}{}^{\mathrm{?}}$ rotational band and 5 ± 3 fs (1.55 MeV) and 370 ± 25 (2.78) for the $\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{9}\text{2}{}^{\mathrm{+}}$ members of the $\text{K}{}^{\mathrm{\pi }}\text{=}\text{1}\text{2}{}^{\mathrm{+}}$ ground-state band. For the Doppler-shift attenuation analysis correction factors of the nuclear and electronic stopping powers were determined by measuring the Doppler-shift attenuation and γ-ray line shape of the 2.78 → 0.20 MeV transition and range values of 100, 200. 300 and 370 keV ¹⁹F nuclei in tantalum. All calculations were done with Monte Carlo methods. The transition strengths are discussed in terms of different theoretical predictions.     

The separation of proton and deuteron spin-dependent effects in the 116Sn(d,p)117Sn reaction

The cross section, vector analyzing power, and proton polarization have been measured for the l_n = 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 ${}^{116}\text{Sn}\text{(}\text{d}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ 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 ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{p}\text{)}\text{Sn}$ and for ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ 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 $\text{l}{}_{\mathrm{n}}\text{= 0}{}^{90}\text{Zr}\text{(}\text{d, p}\text{)}{}^{91}\text{Zr}$ 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.     

Lifetimes of some excited states in 64Ni, 66Zn and 68Zn

Mean lives and excitation energies of the lowest levels in⁶⁴Ni,⁶⁶Zn and⁶⁸Zn were measured with the aid of the (α, α′γ) and (α, pγ) reactions. The γ-rays were detected in coincidence with the outgoing particles. The following mean lives were determined from DSA measurements: 400 ± 150 fs for the level at E_x = 1.35 MeV in ⁶⁴Ni; 270 ± 100, 210 ± 110, 330 ± 200, 80 ± 70 fs for the levels at E_x = 1.87, 2.45, 2.83, 2.94 MeV in ⁶⁶Zn, and 1300 ± 300, > 160, 600 ± 200 fs for the levels at E_x = 1.08, 1.89 and 2.76 MeV in ⁶⁸Zn, respectively.     

181Ta(n, α)178mLu, 178Lu reactions and isomeric states of 17871Lu107

The cross sections for the production of 25 min and 5 min activities due to the isomeric states of ¹⁷⁸Lu, produced by the ¹⁸¹Ta(n, α) reaction, have been measured at four neutron energies in the keV region. From a study of σ_{5 min} (n, α)/σ _{25 min}(n, α) versus E_n, an attempt has been made to assign spins to the 25 min and 5 min isomeric states of ¹⁷⁸Lu.     

Analyzing powers of valence and inner neutron-hole states in 115Sn via the 116Sn(d, t) reaction

The reaction ¹¹⁶Sn($\text{d}$, t)¹¹⁵Sn up to 7.5 MeV excitation energy has been studied at 40 MeV incident energy using a vector polarized deuteron beam. The measured analyzing power reveals strong J-dependence effects and has been used to clearly assign the spin of a number of low-lying states in the ¹¹⁵Sn nucleus. At higher excitation energy, a broad and fragmented bump is observed between 3.7 and 6.0 MeV in ¹¹⁵Sn. This work reports on one of the first attempts to determine the spin of such structure through polarization measurements. The analyzing power data indicates a mixing of spins $\text{J =}\text{9}\text{2}\text{,}\text{1}\text{2}$, in agreement with the excitation of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ inner neutron-hole strengths in the ¹¹⁵Sn nucleus. In addition, some $\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ components are observed around ~ 4.6 MeV excitation energy.     

High-resolution measurements of analogue states in 57Co

Using a proton beam with an overall resolution of 300–400 eV (FWHM) spins, parities and partial widths were determined for all resonances observed (99 s-wave, 42 p-wave, 106 d-wave and one g-wave resonances). Differential cross sections for proton elastic scattering from ⁵⁶Fe were measured at proton energies between 3.1 and 4.2 MeV. Spectroscopic factors and Coulomb displacement energies were extracted for the fragmented analogue resonances which correspond to the $\text{5}\text{2}{}^{\mathrm{+}}\text{(2.506}\text{MeV}\text{)}$, $\text{3}\text{2}{}^{\mathrm{+}}\text{(2.565}\text{MeV}\text{)}$ and $\text{1}\text{2}{}^{\mathrm{?}}\text{(2.687}\text{MeV}\text{)}$ states in ⁵⁷Fe. A value of the s-wave proton strength function was deduced.     

Gyromagnetic ratios of excited states in 107, 109Ag

The gyromagnetic ratios of the lowest excited $\text{3}\text{2}{}^{\mathrm{?}}\text{and}\text{5}\text{2}{}^{\mathrm{?}}$ states in ^{107, 109}Ag were simultaneously measured relative to that of the 2₁⁺ level in ¹⁰⁸Pd. The thin-foil, perturbed γ-ray angular distribution technique was employed utilizing the transient hyperfine magnetic field present at the nuclei of these ions as they swiftly recoiled through a thin magnetized Co foil. The states of interest were Coulomb-excited using beams of 100 MeV ³²S ions. The present measurements yielded $\text{g(}\text{3}\text{2}{}^{\mathrm{?}}\text{;}{}^{107}\text{Ag}\text{) = +0.63 ± 0.09, g(}\text{5}\text{2}{}^{\mathrm{?}}\text{;}{}^{107}\text{Ag}\text{) = + 0.37±0.06, g(}\text{3}\text{2}{}^{\mathrm{?}}\text{;}{}^{109}\text{Ag}\text{) = +0.77 ± 0.10,}\text{and}\text{g(}\text{5}\text{2}{}^{\mathrm{?}}\text{;}{}^{109}\text{Ag}\text{) = +0.36 ± 0.05}$. These findings are compared with weak-coupling and other appropriate model calculations.     

Low-lying states in 95Tc studied with the 93Nb(α, 2nγ)95Tc reaction

Low-lying states in ⁹⁵Tc were studied with the ⁹³Nb(α, 2nγ)⁹⁵Tc reaction. The level scheme was obtained from the γ-γ coincidence measurement. The spin assignment was made on the basis of the observed γ-ray angular distributions and the excitation functions. The $\text{337}\text{keV}\text{7}\text{2}{}^{\mathrm{+}}\text{, 627}\text{keV}\text{(}\text{5}\text{2}{}^{\mathrm{+}}\text{), 882}\text{keV}\text{13}\text{2}{}^{\mathrm{+}}\text{and}\text{957}\text{keV}\text{11}\text{2}{}^{\mathrm{+}}$ states, and possibly state, are found to be strong candidates for the core multiplet states $\text{[(1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{<mtext>p</mtext>}}\text{?2}{}^{\mathrm{+}}\text{]}{}_{\mathrm{J}}$. These states are discussed in term of a weak coupling model and the dressed three-quasiparticle model. The observed γ-ray angular distributions are compared with expectations based on a simple deexcitation model of the (α, 2nγ) reaction.     

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.     

High-spin states and two-quasiparticle structure in 172Hf

Five rotational bands in ¹⁷²Hf have been observed to high spin following the ¹⁶⁰Gd(¹⁶O, 4n)¹⁷²Hf reaction, using γ-γ coincidence techniques. The ground-state band is extended to spin 20⁺ without backbending, in contrast to the neighbouring even-even isotones. The most strongly populated side-band, consisting of separated odd-spin and even-spin sequences, appears to result from the partial decoupling of an i_{$\text{13}\text{2}$} neutron. Three other bands are identified with the following band-heads: an 8^? state at 2006 keV with 163 ns half-life; a 6⁺ state at 1685 keV with a half-life < 16 ns; and a level at 1857 keV with spin 4, 5, 6 or 7 and a half-life < 16 ns. The differences between the bands are discussed in terms of the influence of Coriolis forces and the two-quasiparticle level structure.     

Determination of the static quadrupole moment of the first 2+ states of 122Te, 124Te,and 130Te by heavy-ion coulomb excitation

A Coulomb excitation experiment has been performed on the first 2⁺ states of ¹²²Te, ¹²⁴Te and ¹³⁰Te. The relative excitation probabilities of the first 2⁺ states were measured at backward and forward projectile scattering angles. Particle-γ coincidences were used to identify the inelastic events. The data were analyzed with the aid of the Winther-deBoer multiple Coulomb excitation program. Separate γ-ray angular distribution measurements were made as a function of target recoil velocity to determine the influence of the deorientation effect. The projectile and bombarding energy were chosen to minimize the effect on the experiment of higher state interference due to Coulomb excitation of the first 2⁺ state via the second 2⁺ state. For positive higher state interference the extracted quadrupole moments of the first 2⁺ states are Q₂₊ = ?0.43 ± 0.08 b, ?0.49 ± 0.08 b and ?0.08 ± 0.08 b for ¹²²Te, ¹²⁴Te and ¹³⁰Te respectively. These results and other measurements of Q_2⁺ for the doubly even Te isotopes are used to discuss the model dependent calculations of Q_2⁺.