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.     

Cross sections for 197Au(n, γ)198Au and 115In(n, γ)116mIn in the neutron energy region 2.0–7.7 MeV

The cross sections for the reactions ¹⁹⁷Au(n, γ)¹⁹⁸Au and ¹¹⁵In(n, γ)^116mIn have been measured with the activation method in the neutron energy region 2.0–7.7 MeV. The influence of background neutrons on the results was studied in considerable detail. The main problems are caused by low-energy neutrons produced by charged-particle reactions in the target material and secondary neutrons from nonelastic reactions in the sample and surrounding materials.The measured capture cross sections are generally lower than previous results and the deviation tends to increase with increasing neutron energy. The data are also compared with calculations based on the compound-nucleus model and quite good agreement is obtained.     

The 114In level scheme studied by the (n, γ) reaction

The level scheme of the nucleus ¹¹⁴In has been studied using capture of thermal neutrons. The experimental information is taken from γ singles spectra and γ-γ coincidence spectra and from delayed coincidence measurements. Levels up to 1.4 MeV excitation energy are proposed. Several short lifetimes of excited states in ¹¹⁴In and ¹¹⁶In could be measured. The binding energy of the last neutron in ¹¹⁴In, B_n = 7273.9 ± 1.2 keV, determined in this work is in strong disagreement with previously accepted values. Additional experimental information on the ¹¹⁶In level scheme is given. Six states of the ($\text{π(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{, ν}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$) multiplet (3^? to 8^?) in ¹¹⁴In. The expected close similarity between many low-lying states in ¹¹⁴In and ¹¹⁶In could be confirmed. In particular, it was found that the anomalous high isomeric cross-section ratio of the second isomeric state results from very selective reorientation transitions within the negative-parity multiplet. The coupling constant of the quadrupole part of the residual neutron-proton interaction obtained from a theoretical calculation of the ¹¹⁴In level scheme is similar in size to that of ¹¹⁶In, thus giving credit to the explanation given in our previous ¹¹⁶In work. The splitting of multiplets in doubly odd In nuclei gives additional information for an interpretation of the so-called $\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?}}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ anomaly in stripping studies near A = 110. Transition probability ratios B(M1)/B(E2) and E1 hindrance factors are discussed for both ¹¹⁴In and ¹¹⁶In. No sign of states exhibiting stable deformation similar to those in odd-A In nuclei has been found up to now in the doubly odd In nuclei studied. There is some evidence that these doubly odd In nuclei behave more like Cd than like single closed shell Sn nuclei.     

A neutron decoupled from a rotating odd core in 114Sb and 116Sb

The ^{113, 115}In(α, 3nγ)^{114, 116}Sb reactions have been studied using γ-ray spectroscopic techniques. The experiments included γ-ray excitation function, γ-γ coincidence, lifetime, γ-ray angular distribution and conversion electron measurements. A ΔJ = 1 rotational band has been observed in either of the ^{114, 116}Sb final nuclei. Energy spacings and electromagnetic properties of the band show strong resemblances with those of rotational bands in the adjacent odd-mass Sb nuclei. In addition two-quasiparticle and two-quasiparticle core coupled states have been observed in these nuclei. One isomer was identified in ¹¹⁶Sb, i.e. a J^π = 11⁺ state at 1889 keV ($\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext><mtext>\; =\; 4.0\pm 0.1\; </mtext><mtext>ns</mtext>}}$). A simple model is proposed which explains the ΔJ = 1 band in terms of rotational alignment of the $\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ neutron with the deformed rotating odd-A core.     

Hole-vibration states in 115In

The hole-vibration coupling in the Z = 50 region is investigated by calculating the level structure of ¹¹⁵In. Four proton-hole states are coupled with quadrupole and octupole core vibrations. The phonon energies and the amplitudes of the vibrational motions are taken from experiment, while the single-hole energies are treated as free parameters. Most of the observed features of a quintet of states with $\text{I}{}^{\mathrm{\pi }}\text{=}\text{5}\text{2}{}^{\mathrm{+}}\text{,}\text{7}\text{2}{}^{\mathrm{+}}\text{,}\text{9}\text{2}{}^{\mathrm{+}}\text{,}\text{11}\text{2}{}^{\mathrm{+}}\text{,}\text{13}\text{2}{}^{\mathrm{+}}$, which have enhanced E2 transition strengths to the ground state, are well reproduced by the theory. The hole-vibration coupling produces a strong fragmentation of the single-hole strengths. This is quite in agreement with the results of (d, ³He) experiments on ¹¹⁶Sn.     

High-spin states in 107Sn and 107In isotopes

The isotopes ¹⁰⁷Sn and ¹⁰⁷In were produced through the ¹⁰⁶Cd(³He, 2n)¹⁰⁷Sn and ¹⁰⁶Cd(³He, pn)¹⁰⁷In reactions. They were studied by means of γ-spectroscopy, excitation functions, γγ coincidences and angular distributions of γ-rays. A level scheme is proposed for the newly discovered ¹⁰⁷Sn, and new states belonging to ¹⁰⁷In are given. Microscopic calculations have been performed in a three-quasiparticle approximation for a large number of tin isotopes in order to get a wide view of the systematic evolution of the various states.     

Level properties of the light even Sb nuclei 112, 114, 116Sb

The level properties of ^{112, 114, 116}Sb have been investigated with the reactions ^112,114,116Sn(p, nγ)^112,114,116Sb and ¹¹⁵In(³He, xnγ)^112,114Sb (x = 6, 4). Singles γ and electron spectra, neutron-γ coincidences, γ-γ coincidences, excitation functions and half-lives were measured. Hauser-Feshbach calculations were performed for spin assignments. A number of new levels were found, including two 8^? isomeric states. The results are compared with recently performed 2qp calculations.     

The decays of 121g,mCd to 121In

The decay of isotope-separated activities of ¹²¹Cd produced in fission have been studied by γ-ray and conversion-electron spectroscopy. A level scheme of ¹²¹In has been constructed. Transition probabilities between some levels have been deduced from a lifetime measurement. The experimental results are compared to a recent theoretical study of ¹²¹In.     

A 69Ga, 115In NQR study of polytypes of GaS,GaSe and InSe

Pulsed Fourier transform NQR spectroscopy has been used to study polytypism in the monochalcogenides GaS, GaSe and InSe at 77 K. The spectrum of GaS was consistent with a major contribution from the β phase but showed evidence of higher polytypes, possibly due to ? or γ type faulting. The GaSe spectrum is simply interpreted as an equal mixture of ? and γ types. The four InSe spectra ($\text{I}\text{=}\text{9}\text{2}$¹¹⁵In), showed a multiplicity of lines. The sharpness of the NQR lines of all spectra suggests the existence of regions with a hitherto overlooked high degree of order.     

Fluorescence nucléaire de 115In

Continuous radiation (bremsstrahlung) from a 2 MeV electron accelerator has been used to excite seven nuclear levels in ¹¹⁵In, at 1133, 1291, 1449, 1464, 1487, 1498 and 1610 keV. Mean-life values were calculated for the first five levels and the δ² ratio was also determined for those at 1133 and 1464 keV.     

(γ, γ′) reactions in 89Y, 115In and 197Au at intermediate energies

The yields of isomeric states in ⁸⁹Y, ¹¹⁵In and ¹⁹⁷Au produced by the (γ, γ') reaction have been measured in the energy range 100–800 MeV by the activation method. From the yields the cross sections have been deduced. Large cross sections around the first pion resonance are found. The experimental results are compared to calculations based on the impulse approximation.     

Static quadrupole moment of the 8− state of 112In

The quadrupole coupling constant $\text{(}\text{eQV}{}_{\mathrm{zz}}\text{h}\text{)}$ of the 8^? 606 keV level of ¹¹²In has been measured by the DPAD method in the hexagonal lattice of metallic cadmium. The quadrupole moment of the level is deduced to be |Q| = 0.093(6) in agreement with the theoretical value for the configuration $\text{[π(}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{ν(}\text{h}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}{}^{\mathrm{n}}\text{]}{}_{\mathrm{8?}}$.     

Angular distributions for target residues in reactions of 14N and 12C with 115In

Mechanisms of the reactions of ¹²C and ¹⁴N with ¹¹⁵In have been investigated by measuring the angular distributions of the target residues. Various possible transfer mechanisms are discussed with the help of kinematic analysis and a semiclassical transfer model. Interesting secondary (or tertiary) peaks are seen near 90 in the angular distributions for most target residues.     

Gamma rays from resonance neutron capture in 115In

Gamma rays in the range 5.4–6.7 MeV have been studied for 31 s-wave neutron resonances of ¹¹⁵In, selected by time of flight in the range 3–430 eV. In a subsidiary experiment, spin J = 5 has been assigned to 17 and J = 4 to 14 resonances by measuring intensity variations of some strong low-energy transitions. The reduced widths averaged over all initial states of the same spin have been estimated for 41 primary transitions: these values have provided information on the spin and parity of the corresponding ¹¹⁶In final states. Overall mean values of E1 and M1 radiative strength have been calculated. The width distribution has been fitted with a χ² function with ν = 1.10^+0.27_?0.09 degrees of freedom for M1 and ν = 1.42 ^{+ 0.014}_?0.08 for E1 radiation. An estimate of the spin cut-off parameter σ = 3.6_?0.4^{+ 0.8} has been derived. A non-statistical effect already evidenced in previous measurements has been confirmed, consisting of a strong modulation of the radiative strength against resonance energy, correlated also with the local neutron strength function. In addition, it has now been shown that this structure is due to E1 radiation only.     

Differential cross sections for radiative capture of energetic protons by 110Cd and 115In

Spectra of high-energy photons following the radiative capture of 8–22 MeV protons in ¹¹⁰Cd and ¹¹¹In are measured. The (p, γ) differential cross sections at 90° with respect to the beam axis is deduced from the integration of measured spectra. The photon angular distribution is measured for the ${}^{110}\text{Cd}\text{(}\text{p}\text{, γ}{}_0\text{)}$ reaction, too, at 13 MeV incident energy. Satisfactory agreement between theory and experiment is obtained by using the direct-semidirect model for dipole and quadrupole fast nucleon radiative capture.     

The quadrupole moments of the 5− states in 116Sn, 118Sn and 120Sn

The quadrupole interaction frequencies $\text{ω}{}_0\text{=}\text{3eQ}{}_1\text{V}{}_{\mathrm{zz}}\text{41(21-1)}\text{h}\text{?}$ in the 5^? state of ¹¹⁸Sn have been measured by time differential perturbed angular correlation technique in Sn, Sb and (95% Sn+5% Sb) environments. The ω₀ for ¹¹⁶Sn was determined in Sn environment only. With the help of the known electric field gradient ¹) of Sn in a Sn lattice the quadrupole moments have been deduced as $\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{118}\text{Sn}\text{) = ±0.10(4) b}\text{and}\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{116}\text{Sn}\text{) = ±0.165(60)}\text{b}$. These values together with the known²) quadrupole moment of the analogous 5^? state in ¹²⁰Sn are interpreted in terms of the pure single-particle model. The data exhibit the expected strong systematic variation of Q_I with the number of particles in the h_{$\text{11}\text{2}$}. subshell which is being filled with 1, 3 and 5 neutrons in ¹¹⁶Sn, ¹¹⁸Sn, and ¹²⁰Sn, respectively.     

缺中子核素101In低位同核异能态的首次观测

在兰州重离子加速器冷却储存环（HIRFL-CSR）上,用初级束流112Sn35+轰击了靶厚约10 mm的Be靶,产生了101In的基态和低位同核异能态。这些实验产生的碎片每25 s经过放射性束流线RIBLL2的筛选后注入到实验环CSRe中,利用飞行时间探测器测量离子在CSRe中的回旋周期。在此次实验中,磁场晃动会导致离子在环内的循环周期发生改变,传统的离子鉴别方法难以完成大部分离子的鉴别。通过发展和运用单次注入离子鉴别这一新的离子鉴别方法,有效地消除了磁场晃动对于离子鉴别的影响,并清楚地将101In基态和低位同核异能态鉴别出来,从而首次在实验中观测到101In的低位同核异能态。实验得到的激发能与理论外推值在112 keV的误差范围内一致,其低位同核异能态的寿命大于200 μs。Isochronous mass spectrometry has been applied to 112Sn projectile fragments at the HIRFL-CSR facility in Lanzhou. To produce short-lived nuclei of interest, we used projectile fragmentation of 112Sn35+ primary beams in a~10 mm thick 9Be production target. The fragments were selected and analyzed by RIBLL2 and injected into the experimental storage ring(CSRe) every 25 s. To measure revolution times of stored ions,we used a Time-Of-Flight detector installed in CSRe. A new particle identification method was developed to distinguish ions on the measured revolution time spectrum for each injection. Based on this method, the shifts of the revolution time due to instable dipole magnet fields can be corrected and the ground and isomeric states of 101In have been well-resolved. The measured excitation energy is consistent with the theoretical value in the error range of 112 keV. The lifetime of the isomeric states of 101In is more than 200 μs.     

Levels and transition probabilities in 124In as observed in the decay of 124Cd

The levels of ¹²⁴In, which are populated in the decay of ¹²⁴Cd, have been investigated at the OSIRIS on-line facility by means of conversion electron and γ-ray spectroscopy. A γ-γ coincidence measurement combined with the deduced transition intensities permitted construction of a unique level scheme. The half-life of the 243 keV level of ¹²⁴In has been determined to be 50 ± 6 ns by the method of delayed coincidences.     

A microscopic description of inelastic 12C scattering from 208Pb

Heavy-ion inelastic scattering is described microscopically by using an effective nucleon-nucleon interaction and RPA hole-particle wave functions. The relative cross sections for different multipoles can be sensitive to the range of the interaction. The strength is determined by fitting elastic scattering. The model is used to analyze 98 MeV ¹²C ions exciting ²⁰⁸Pb. The range required is shorter than that for the bare interaction between nucleons. Collective model fits are also presented for comparison.     

Trapping of defects at 111In impurities In e−-irradiated Al

The trapping and detrapping of interstitials and vacancies at ¹¹¹In impurities in aluminium after low-temperature electron irradiation was observed. Using perturbed angular correlation of ¹¹¹Cd the electric field gradients caused by nearby lattice defects were determined and used to monitor the formation and dissociation of impurity-defect complexes.