The 1h92 proton orbit size in 209Bi

Angular distributions of α-particles from the reaction ²⁰⁹Bi(t, α)²⁰⁸Pb (ground state) have been measured at bombarding energies E_t = 8.5 MeV and E_t = 9.0 MeV. Zero-range (ZR) DWBA analyses of the data are used to determine the radial extent of the wave function of the $\text{lh}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ orbit in which the transferred proton is bound in ²⁰⁹Bi. The applicability of the sub-Coulomb ZR DWBA treatment is investigated by comparison of ZR and exact finite-range DWBA calculations. A value of the (t, α) normalization constant of (20.8 ± 3.1) × 10⁴ MeV² · fm³, based on forward dispersion relations, has been obtained from this comparison. The asymptotic amplitude of the wave function is measured directly and the rms radius is extracted via a Woods-Saxon model. A value of √〈r²〉 = 6.10_?0.08^+0.12 fm, corresponding to a point proton and to a local Woods-Saxon potential, is obtained. The rms radius and radial wave function of the $\text{1}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ proton are compared with the results of electron scattering and muonic atom data on targets of ²⁰⁹Bi and ²⁰⁸Pb and with the results of Hartree-Fock calculations.     

Proton 1h112 excitations in odd-mass N = 82 nuclei

The structure of negative-parity states in odd-mass N= 82 isotones (135 ≦ A ≦ 145) is investigated in the framework of a model which is based on coupling one $\text{1h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ proton to π = + 1 states of the appropriate doubly-even isotonic core. It is shown that an effective model-space truncation can be achieved if only core states in the vicinity of the yrast line are taken into account. These have been selected from the several hundreds or even thousands of states obtained from shell-model calculations, where the $\text{1g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$, $\text{2d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$, $\text{2d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{3s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ single- are assumed to be occupied. Spectroscopic data are calculated and predictions on the structure of low-lying π = ? 1 states are discussed and compared as far as possible to experimental findings. Thereby, the particle-core coupling approach is shown to be capable of describing essential properties of negative-parity levels in the N = 82 nuclei considered.     

The d52 analog strength in 59Cu

Isobaric analog states of the strongest $\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ parent states in ⁵⁹Ni were investigated in the reaction ⁵⁸Ni + p. Proton spectroscopic factors were derived whose sum was found to be in good agreement with the sum of the parent strengths. The absolute transition probability of the E1 γ-decay populating the ⁵⁹Cu ground state was estimated and compared with single-particle predictions.     

On the question of fine structure in νp and EK for 233U and 235U

The question of fine structure in the variation of the average number of prompt neutrons, $\text{ν}{}_{\mathrm{<mtext>p</mtext>}}$, emitted per fission with energy in the neutron fission of ²³³U and ²³⁵U has been examined. Consistent structure has been found in measurements of both $\text{ν}{}_{\mathrm{<mtext>p</mtext>}}\text{and}\text{E}{}_{\mathrm{<mtext>K</mtext>}}$ (the average total fission fragment kinetic energy) for ²³³U. Channel analysis of the neutron fission cross section of ²³³U allows the structure to be calculated quantitatively provided the collective energy at the second hump in the fission barrier is weakly coupled to the nuclear degrees of freedom at scission. A similar calculation for neutron fission of ²³⁵U supports the case for the absence of fine structure in $\text{ν}{}_{\mathrm{<mtext>p</mtext>}}\text{and}\text{E}{}_{\mathrm{<mtext>K</mtext>}}$ for this nucleus.     

Hyperfine interaction in the 4D32 and the 4D52 levels of sodium

We have excited the $\text{4D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{4D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ levels of sodium using Doppler-free two-photon excitation. By measuring the polarization rate in zero magnetic field of the fluorescence lines, we have deduced the following values for the hyperfine interaction $\text{|A(}\text{4D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{) | =}\text{0.23 ± 0.12 MHz}$ and $\text{|A(}\text{4D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)| <}\text{0.28 MHz}$. The value of $\text{A(}\text{4D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{)}$ is in disagreement with the one reported by Schenk and Pillof.     

The γ-decay of the g92 analogue state in 59Cu

An investigation of the γ-decay of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ analogue state in ⁵⁹Cu has been performed using the ⁵⁸Ni(p, γ)⁵⁹Cu reaction. The (p, γ) excitation function has been taken in the range E_p = 3450–3650 keV. The decay schemes of the (p, γ) resonances at E_p = 3483, 3532 and 3547 keV, measured with Ge(Li) detectors, lead to eight new levels in ⁵⁹Cu with excitation energies between 1.8 and 4.7 MeV and to spin assignments of several states. The spins of the first two resonances are found to be ($\text{1}\text{2}$, $\text{3}\text{2}$) and ($\text{5}\text{2}$). The spin of the E_p = 3547 keV resonan is, from angular distributions, uniquely determined to be $\text{J}{}^{\mathrm{\pi }}\text{=}\text{9}\text{2}{}^{\mathrm{+}}$ and this state is found to be the unfragmented analogue state of the $\text{E}{}^1\text{= 3.062}\text{MeV}$, $\text{J}{}^{\mathrm{\pi }}\text{=}\text{9}\text{2}{}^{\mathrm{+}}$ parent state in ⁵⁹Ni. The measured complete decay scheme of this resonance shows that its isovector M1 decay is in disagreement with all existing theoretical predictions.     

The distribution of 3p12 strength in 209Bi

An optimized Woods-Saxon potential, which gives excellent fits to the observed proton states in ²⁰⁹Bi and ²⁰⁷Tl, is used to calculate the excitation energy of the unbound $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ proton state in ²⁰⁹Bi. Using the wave functions given by the above potential, the strength of the core-particle interaction is calculated. The effect of the vibration of the core on the fragmentation of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state is estimated. It is found that the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 5.123 MeV loses more than 80% of its strength to five $\text{1}\text{2}{}^{\mathrm{?}}$ collective states in ²⁰⁹Bi and the observed $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 3.64 MeV is actually an almost equal mixture of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ single-proton state and the ($\text{4}{}^{\mathrm{+}}\text{, 1}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$) collective state.     

The E2 transition probability and effective charge for the neutron i132 subshell in lead isotopes

In (heavy ion, xn) reactions, X-rays and low energy γ-rays emitted by the compound nuclei are investigated using a catcher system for recoiling nuclei within the 10–100 keV energy range. The nucleide ¹⁹⁸Pb is studied by means of this technique. A 90 keV E2 (or E2 + M1) transition is identified together with information related to the 12⁺ → 10⁺E2 transition energy. The B(E2; 12⁺ → 10⁺) value is deduced. The effective charge extracted from the analysis of the reduced transition probability between two members of the ($\text{vi}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?2}}$ multiplet is compared to the corresponding values for other lead isotopes.     

The l-forbidden 3p32 → 2f52M1 transition in 207Pb

The branching ratio for the transition from the 0.90 MeV second excited to the 0.57 MeV first excited state in ²⁰⁷Pb has been measured to be (0.59 ± 0.09)%. The corresponding B(M1) exceeds recent theoretical predictions.     

Gamma-ray spectroscopy of 64Zn and 65Zn and the role of the g92 orbital

Measurements of γ-ray excitation functions, γ-γ coincidence spectra and γ-ray angular distributions have been made. following the reactions ⁶¹Ni(α, n)⁶⁴Zn, ⁶²Ni(α, n)⁶⁵Zn, ⁵⁶Fe(¹⁴N, αnp)⁶⁴Zn, ⁵⁶Fe(¹²C, 2pn)⁶⁵Zn, and ⁵⁴Fe(¹²C, 2p)⁶⁴Zn. Among the new levels observed in ⁶⁴Zn are those at 5624 keV, 6765 keV, 6940 keV, and 6124 keV, the last one with a suggested assignment of (9^?). In ⁶⁵Zn. ten new levels probably in the positive-parity chain, with spin up to ($\text{21}\text{2}$), and a few others, have been found. Comparison of the ⁶⁵Zn positive-parity levels with the ⁶⁴Zn ground-state band supports the concept of a single neutron in the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ orbital weakly coupled to a core essentially identical to ⁶⁴Zn. Many high-spin states in ⁶⁴Zn itself can be aggregated into bands whose band heads are suggestive of two-quasiparticle states involving one $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ excitation.     

Magnetic moment and half-life of the isomeric 112− state in 107Cd

An isomeric level in ¹⁰⁷Cd at 845 keV populated by the reactions ¹⁰⁷Ag(p, n), ¹⁰⁶Cd(d, p) and ¹⁰⁴Pd(α, n) has been observed. The half-life of this state is $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 77(7)}\text{ns}$, and the spin and parity are $\text{I}{}^{\mathrm{\pi }}\text{=}\text{11}\text{2}{}^{\mathrm{?}}$. The magnetic moment has been determined by the pulsed beam time-differential perturbed angular distribution method (DPAD) to be μ = ?1.012(12) n.m.     

Gamma-ray spectroscopy of 66Zn and 67Zn and the role of the g92 orbital

Measurements of γ-ray yield functions, γ-γ coincidence spectra and y-ray angular distributions following the ⁶⁴Ni(α, n) and (α, 2n) reactions have been made. Beam energies of 17 to 25 MeV were used. Among the new levels observed, with their proposed spin-parity assignments, are: in ⁶⁶Zn, 3708 keV, (5)⁺; 3896 keV, 5^?; 4812 keV, (7^?); 5110 keV, (8^?); 6417 keV; (10^?); 7516 keV, (12⁺); and in ⁶⁷Zn, 2937 keV, $\text{13}\text{2}{}^{\mathrm{+}}$; 3491 keV, $\text{17}\text{2}$ or $\text{19}\text{2}$; 3492 keV, ($\text{13}\text{2}$(si+)); 4221 keV, ($\text{19}\text{2}$^?); 4631 keV, ($\text{21}\text{2}{}^{\mathrm{+}}$); 4685 keV, ($\text{21}\text{2}$^?). Comparison between the ground-state sequence, 0⁺ to 6⁺, in ⁶⁶Zn and the first $\text{9}\text{2}$⁺ to $\text{21}\text{2}$⁺ levels in ⁶⁷Zn strongly suggests that the latter be described as a g_{$\text{9}\text{1}$} neutron orbital weakly coupled to the ⁶⁶Zn core. Other sequences of high-spin ⁶⁶Zn states are proposed to be formed from two-quasiparticle states containing the g_{$\text{9}\text{2}$} excitation, coupled to the same ground-state sequence.     

f72 neutron occupancies in the Ca isotopes

Methods of obtaining nucleon occupancies from total energy-weighted sum rules for spectroscopic factors are described and applied to $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ neutron transfer data for Ca isotopes. The $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ neutron occupancies obtained are consistent with shell model expectations and, for ⁴¹Ca and ⁴³Ca, with values previously obtained from an analysis using non-energy-weighted sum rules.     

The radial distribution of the 1f72 neutron in 41Ca from the 40Ca(13C, 12C)41Ca reaction

The reaction ⁴⁰Ca(¹³C, ¹²C)⁴¹Ca leading to the ground and low-lying $\text{3}\text{2}$^? levels has been studied at bombarding energies of 18.5 and 19.0 MeV, close to the Coulomb barrier. The cross sections have been analysed using the DWBA with previously measured calibrations to obtain the rms radii of 1f_{$\text{7}\text{2}$} and 2p_{$\text{3}\text{2}$} orbits in the ⁴¹Ca levels. The rms radius of the 1f_{$\text{7}\text{2}$} point neutron orbit in the ground state relative to the ⁴⁰Ca core was determined to be 3.89 ± 0.12 fm. This is compared with various theoretical predictions based on Hartree-Fock theory. The 1f_{$\text{7}\text{2}$} orbit radius gives the point neutron excess size to a good approximation for comparison with the value of 3.45 fm deduced from Coulomb energy differences. The consistency of the results with ⁴⁰Ca(t, d)⁴¹Ca experiments using a (t/d), zero-range normalization of 3.26 × 10⁴ MeV² · fm³ is demonstrated, and trends in neutron size parameters through the Ca isotopes are discussed.     

Polarization transfer in the 2H(d,n)3He reaction at θ = 0°

The vector polarization transfer coefficient K_y^y′ and the tensor analyzing power A_zz have been measured for the ²H($\text{d}$$\text{n}$)³He reaction at θ = 0° over an incident deuteron energy range from 1 to 15 MeV in 0.5 MeV steps. The results agree with the previous ²H($\text{d}$$\text{n}$)³He measurements of Simmons et al. and are nearly identical to the ²H($\text{d}$$\text{n}$)³H measurements of Clegg et al. in the region of overlap. The present results provide an accurate and complete set of the observables necessary to use the ²H($\text{d}$,$\text{n}$)³He reaction as a source of polarized neutrons.     

Effective interactions and the 1f72 sub-shell closure in the 2p-1f shell

It is estimated that the ground state of ⁵⁶Ni as given by the Kuo-Brown effective interaction modified to satisfy the restrictions imposed by the BE2 systematics contains about 13 particles in the $\text{1f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ shell.     

Configurational mixing and the magnetic moment of f72-Nucleons

It is shown that, after the corrections due to deformed components in the wave functions have been removed, the new measurement of the magnetic moment of the 6⁺ state in ⁴²Ca together with the corresponding results from ⁴¹Ca, ⁴¹Sc as well as the β-decay results ⁴¹Sc → ⁴¹Ca, fit a picture in which the correction to the Schmidt magnetic moment of the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ nucleons is pure isovector and consists of a 10 percent reduction of the 〈Σσ₂τ₃〉 and δg_l = 0.15 τ.